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Sample records for cells stress oxydant

  1. Les effets de l'exercice physique sur le stress oxydant et l'inflammation dans les maladies vasculaires

    OpenAIRE

    Chirico, Erica

    2012-01-01

    Sickle cell disease (SCD) and atherosclerosis are two very different and distinct diseases thatshare similar underlying characteristics. Sickle cell disease is a hemoglobinopathycharacterized by a genetic mutation which causes the normal blood cells to become rigid andweak. The resulting pathophysiological effects, including sickling, vaso-occlusion, andadhesion, involve the production of oxidative stress and inflammation. Atherosclerosis is achronic inflammatory disease that is characterized...

  2. The results of the lipids peroxidation products on the DNA bases as biological markers of the oxidative stress; Les adduits des produits de la peroxydation lipidique sur les bases de l'ADN comme biomarqueurs du stress oxydant

    Energy Technology Data Exchange (ETDEWEB)

    Falletti, O

    2007-10-15

    Different ways of DNA damages have been studied, among these ones the direct way of DNA damages formation by the reactive oxygen species (R.O.S.). This way leads to the formation of oxidative DNA damages. In 1990, works have suggested an indirect way of DNA damages formation, the lipids peroxidation. Instead of oxidizing directly DNA, the R.O.S. oxide the lipids present in the cells and their membranes; The products coming from this degradation are able to provoke DNA damages. This way has not been studied very much. The work of this thesis is axed on this DNA theme and lipids peroxidation. In the first chapter, we begin by presenting DNA and the direct way of oxidative damages formation by the R.O.S.Then, we speak about the cell lipids suffering oxidation reactions and the different ways of lipids oxidation. Then, we present how the lipid peroxidation is a source of damages for DNA. (N.C.)

  3. Stress Transmission within the Cell

    OpenAIRE

    Stamenović, Dimitrije; Wang, Ning

    2011-01-01

    An outstanding problem in cell biology is how cells sense mechanical forces and how those forces affect cellular functions. During past decades, it has become evident that the deformable cytoskeleton (CSK), an intracellular network of various filamentous biopolymers, provides a physical basis for transducing mechanical signals into biochemical responses. To understand how mechanical forces regulate cellular functions, it is necessary to first understand how the CSK develops mechanical stresse...

  4. OXYDATION DU CYCLOHEXANE PAR COMPLEXE DE RUTHÉNIUM

    OpenAIRE

    HAMOUDI, Badreddine

    2008-01-01

    Le complexe RuCl2(PPh3)3 a été préparé dans le but de son application sur la réaction d’oxydation du cyclohexane en cyclhexanol et cyclohexanone. Les analyses par chromatographie en phase gaz sur la phase organique montrent la production de l’alcool et la cétone dans le cas du t-BuOOH comme oxydant, ce qui n’est le cas avec l’eau oxygénée et l’oxygène moléculaire. La réaction a été effectuée dans différents solvants, où l’eau a apportée une meilleure conversion par rapport a...

  5. Mechanisms of cell propulsion by active stresses

    Energy Technology Data Exchange (ETDEWEB)

    Carlsson, A E, E-mail: aec@wustl.edu [Department of Physics, Washington University, Campus Box 1105, One Brookings Drive, St. Louis, MO 63130 (United States)

    2011-07-15

    The mechanisms by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored by using a simplified model of the cytoskeleton as a viscous gel containing active stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of active stress and cell-substrate friction. It is found that (i) the cell velocity is given by a function that quantifies the asymmetry of the active-stress distribution, (ii) gradients in cell-substrate friction can induce motion even when the active stresses are symmetrically distributed, (iii) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell and (iv) the cell velocity depends biphasically on the cell-substrate adhesion strength if active stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed.

  6. Activité physique et produits dérivés du soja : intérêts dans la prise en charge du stress oxydant associé au diabète de type 1

    OpenAIRE

    Malardé, Ludivine

    2012-01-01

    Oxidant stress (OS) is well known to contribute to the onset and the development of diabetic complications. OS mainly result from marked rises in blood glucose level. Insulin treatment is required to keep patients alive, but fails to prevent long term complications progression, which result from hyperglycemic induced OS.In healthy people, diet and/or physical activity succeed to significantly reduce OS. Physical activity exhibit moreover glucoregulatory properties.Consequently, the aim of thi...

  7. Dendritic cells are stressed out in tumor.

    Science.gov (United States)

    Maj, Tomasz; Zou, Weiping

    2015-09-01

    A recently paper published in Cell reports that dendritic cells (DCs) are dysfunctional in the tumor environment. Tumor impairs DC function through induction of endoplasmic reticulum stress response and subsequent disruption of lipid metabolic homeostasis.

  8. Oxidation films morphology; Sur la morphologie des pellicules d'oxydation

    Energy Technology Data Exchange (ETDEWEB)

    Paidassi, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    After studying the oxidation of several pure polyvalent metals (Fe, Cu, Mn, Ni, U) and of their oxides at high temperature and atmospheric pressure, the author suggests how to modify the usual representation of the oxide film (a piling of different oxide layers, homogeneous on a micrographic scale with a equi-axial crystallisation, free of mechanical tensions, with flat boundary surfaces) to have it nearer to reality. In this first part, the author exposes the study of the real micrographic structure of the oxidation film and gives examples of precipitation in the oxides during the cooling of the oxidised sample. (author) [French] En se basant sur les etudes qu'il a faites sur l'oxydation aux temperatures elevees et a la pression atmospherique de quelques metaux purs a valences multiples (Fe, Cu, Mn, Ni, U), et de leurs oxydes, l'auteur suggere comment le schema qui representerait la pellicule comme etant une superposition de diverses couches d'oxydes, homogenes micrographiquement, a cristallisations equiaxes, depourvues de tensions mecaniques et separees par des interfaces plans, doit etre modifie pour s'ajuster a la realite. Dans cette premiere partie, l'auteur etudie la structure micrographique reelle des pellicules d'oxydation et donne des exemples de precipitation dans les oxydes au cours du refroidissement des echantillons oxydes. (auteur)

  9. Méthodes générales de synthèse des catalyseurs à base d'oxydes General Synthesis Methods for Mixed Oxide Catalysts

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    Courty Ph.

    2006-11-01

    Full Text Available De nombreux procédés industriels (industrie céramique, électronique, nucléaire catalyse hétérogène utilisent des matériaux constitués d'oxydes mixtes. Les études fondamentales réalisées en catalyse et leurs applications industrielles montrent qu'au-delà des diverses interprétations fines de l'activité catalytique des oxydes mixtes, une notion plus générale se dégage, celle de l'homogénéité de la phase active, donc du premier intermédiaire de fabrication du catalyseur (le précurseur. Les différentes méthodes de synthèse des oxydes mixtes, puis des catalyseurs, sont alors exposées. Pour chacune d'entre elles, il est montré comment l'obtention d'un précurseur homogène peut être favorisée et maintenue. Un exemple illustre le cas de l'oxyde mixte déposé sur support. Finalement, l'étape de mise en forme de l'oxyde mixte est évoquée, l'aspect économique de la fabrication du catalyseur conclut ce texte. A great mony industrial processes (ceramics, electronics, nuclear energy, hererogeneous catalysis use materials made up of mixed oxides. Fundamental research on catalysis and its industrial applications has shown that, over and beyond the various subtle interpretations of the catalytic activity of mixed oxides, a more general concept emerges, i. e. that of the homogeneity of the active phase, hence of the first catalyst-manufacturing intermediate (the precursor. Different synthesis methods for mixed oxides, and then for cotalysts, are described. The demonstration is made for each of them how the production of a homogeneous precursor con be enhanced and maintained. An example illustrotes the case of a mixed oxide deposited on a carrier. To conclude, the shaping of the mixed oxide is described, followed by the economic aspect of catalyst manufacturing.

  10. Cell wall remodeling under abiotic stress

    OpenAIRE

    Tenhaken, Raimund

    2015-01-01

    Plants exposed to abiotic stress respond to unfavorable conditions on multiple levels. One challenge under drought stress is to reduce shoot growth while maintaining root growth, a process requiring differential cell wall synthesis and remodeling. Key players in this process are the formation of reactive oxygen species (ROS) and peroxidases, which initially cross-link phenolic compounds and glycoproteins of the cell walls causing stiffening. The function of ROS shifts after having converted a...

  11. Study and fabrication of solid oxide fuel cells through tape casting and co-sintering; Etude et realisation par coulage en bande et co-frittage de cellules de pile a combustible a oxydes solides

    Energy Technology Data Exchange (ETDEWEB)

    Grosjean, A

    2004-11-15

    This work is dedicated to the devising of a low-cost fabrication process of solid oxide fuel cells (SOFC). Technical requirements impose the shaping method: stripe casting as well as the materials used: Yttria-stabilized zirconia (YSZ), nickel and lanthanum manganite doped with strontium (LSM). In order to comply with environmental requirements the developed process uses an aqueous barbotine solvent. We get electrodes and the electrolyte separately, the use of an absorbent drying process has enabled us to join 3 layers to form an elementary cell with great interfacial homogeneity. The resistance of the cell to sintering has been improved through the symmetrization of the deformations of the cell. In order to interpret the low electrical properties of the cell and its quick damaging, transmission microscopy studies have been performed. These studies have shown 2 facts. First, 2 isolating phases appear at the cathode (at the LSM/YSZ interface) because of a too high sintering temperature and secondly, a quick clustering of nickel grains appears during cell operation that leads to a local loss of the nickel grid percolation. This problem has been solved by increasing the size of nickel oxide grains from 0.5 {mu}m to 3 {mu}m) to stabilize the microstructure. The issue of the reactivity at the LSM/YSZ interfaces was tackled in 2 different ways, we have tried to lower the sintering temperature by using a zirconia nano-powder first and then by replacing zirconia in the electrolyte by gadolinium-doped ceria. The use of zirconia nano-powder has failed to decrease sintering temperature while preserving the electrolyte density and the use of ceria has triggered instabilities that have not yet been solved. Despite all these drawbacks, this process allows the fabrication of an excellent anode/electrolyte interface. (A.C.)

  12. Réduction de l'oxyde d'azote par la suie dans les produits de combustion Reduction of Nitric Oxyde by Soot in Combustion Products

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    De Soete G.

    2006-11-01

    Full Text Available On a étudié dans un réacteur à lit fixe la réduction du NO par de la suie formée dans des flammes riches de mélanges éthane/oxygène/argon. Le mélange gazeux traversant le réacteur est de l'argon dopé avec du NO; dans certains cas ce mélange est enrichi d'hydrogène ou d'oxyde de carbone. En présence d'hydrogène ou d'oxyde de carbone, ces vitesses sont nettement plus grandes qu'avec la suie seule. La comparaison avec des vitesses réactionnelles obtenues sur des lits fixes composés d'autres matériaux solides, tels que l'alumine, montre que la réduction de l'oxyde d'azote se fait principalement par une réaction hétérogène avec l'hydrogène et l'oxyde de carbone catalysée par la suie. D'autres matériaux solides,tels que des oxydes réfractaires présentent une activité catalylique aussi importante que la suie. Cette observation fournit une nouvelle explication de l'effet connu de certains additifs sur la réduction de NO dans les flammes. Dans la seconde partie de l'étude, on mesure la réduction des oxydes d'azote dans les flammes fuligineuses de prémélange. De l'argon dopé par de l'oxyde d'azote est injecté dans les produits de combustion de ces flammes chargés de suie; l'introduction du NO est faite à différentes distances derrière le brûleur, correspondant à différents niveaux de température des produits de combustion. La réduction fractionnelle des oxydes d'azote est mesurée en fonction de la concentration en suie, en hydrogène et en oxyde de carbone, en faisant varier la composition du mélange inflammable. Les résultats expérimentaux sont en bon accord avec la réduction calculée en se basant sur les informations cinétiques obtenues en lit fixe. The kinetics of nitric oxide réduction by soot collected from hydrocarbon flames is studied in a fixed-bed reactor. The gas flow traversing thé reactor is either argon with NO, or argon with hydrogen and NO, or argon with carbon monoxide and NO. In th

  13. Sensing the Heat Stress by Mammalian Cells

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    Cates Jordan

    2011-08-01

    Full Text Available Abstract Background The heat-shock response network controls the adaptation and survival of the cell against environmental stress. This network is highly conserved and is connected with many other signaling pathways. A key element of the heat-shock network is the heat-shock transcription factor-1 (HSF, which is transiently activated by elevated temperatures. HSF translocates to the nucleus upon elevated temperatures, forming homotrimeric complexes. The HSF homotrimers bind to the heat shock element on the DNA and control the expression of the hsp70 gene. The Hsp70 proteins protect cells from thermal stress. Thermal stress causes the unfolding of proteins, perturbing thus the pathways under their control. By binding to these proteins, Hsp70 allows them to refold and prevents their aggregation. The modulation of the activity of the hsp70-promoter by the intensity of the input stress is thus critical for cell's survival. The promoter activity starts from a basal level and rapidly increases once the stress is applied, reaches a maximum level and attenuates slowely back to the basal level. This phenomenon is the hallmark of many experimental studies and of all computational network analysis. Results The molecular construct used as a measure of the response to thermal stress is a Hsp70-GFP fusion gene transfected in Chinese hamster ovary (CHO cells. The time profile of the GFP protein depends on the transient activity, Transient(t, of the heat shock system. The function Transient(t depends on hsp70 promoter activity, transcriptional regulation and the translation initiation effects elicited by the heat stress. The GFP time profile is recorded using flow cytometry measurements, a technique that allows a quantitative measurement of the fluorescence of a large number of cells (104. The GFP responses to one and two heat shocks were measured for 261 conditions of different temperatures and durations. We found that: (i the response of the cell to two

  14. Pulmonary mitochondrial alterations and oxidative stress in response to ozone exposure: Effects of age and an omega-3 enriched diet; Alterations mitochondriales et stress oxydant pulmonaire en reponse a l'ozone: effets de l'age et d'une supplementation en omega-3

    Energy Technology Data Exchange (ETDEWEB)

    Servais, St.

    2004-04-15

    Ozone (O{sub 3}) is one of the molecular species most reactive to which are exposed living species. O{sub 3} acts primarily on the pulmonary system by inducing oxidative stress. Because susceptibility to oxidative stress varies with age, we studied alterations of pulmonary balance between production of reactive oxygen species (ROS) and their elimination, in immature (21 days), adult (6 months) and old rats (20 months) during O{sub 3} exposure (0,5 ppm, 12 h/day for 7 days). For this purpose we have specifically studied pulmonary mitochondria as ROS source, main antioxidant enzyme activities, contents in stress protein (HSP72), 8-oxodGuo and DNA adducts resulting from lipid peroxidation. These works have shown that our protocol of O{sub 3} exposure did not induce lung oxidative stress in adult rats. We confirmed that immature and old rats were more sensitive during O{sub 3} challenge than adults. Indeed, O{sub 3} generates oxidative stress which leads to modification of ventilatory function and pulmonary DNA oxidation in these two populations. Parameters which take part in greatest susceptibility to O{sub 3} differ according to the age. We concluded that the mitochondria is not a major source of pulmonary ROS in our model of O{sub 3} exposure. Secondly, with the sights of anti-inflammatory properties of polyunsaturated fatty acids {omega}3, we studied the effect of a {omega}3 supplementation in immature and old rats exposed to O{sub 3}. The supplementation in {omega}3 limits the pulmonary DNA oxidation in immature and old rats. Paradoxically, in old rats this supplementation provokes an increase in lipid peroxidation susceptibility. (author)

  15. Les oxydes d'azote dans l'environnement Nitrogen Oxides in the Environment

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    Oppeneau J. C.

    2006-11-01

    Full Text Available Le présent article expose les concentrations en oxydes d'azote rencontrées dans l'environnement et fait la part des origines naturelles et anthropogéniques. II présente une des manifestations les plus connues des interactions entre les oxydes d'azote, les molécules organiques, la vapeur d'eau et le rayonnement solaire le brouillard photochimique. Un certain nombre de données sur les effets d'oxydes d'azote sur l'homme et le milieu sont cités et il est mentionné que de nombreuses recherches sont à effectuer pour préciser les connaissances actuelles. Enfin, les réglementations présentes et futures sont décrites. This article describes concentrations of nitrogen oxides found in the environment and explains their natural and anthropogenic origins. It describes one of the best known examples of interactions between nitrogen oxides, organic molecules, water vaporand solorradiation, i. e. photochemical smog. Various data are brought outconcerning the effects of nitrogen oxides on man and the environment, and mention is mode of the many research projects being carried out ta specify current knowledge. Present and future regulations are also described.

  16. Peroxiredoxins, oxidative stress, and cell proliferation.

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    Immenschuh, Stephan; Baumgart-Vogt, Eveline

    2005-01-01

    Peroxiredoxins (Prxs) are a family of multifunctional antioxidant thioredoxin-dependent peroxidases that have been identified in a large variety of organisms. The major functions of Prxs comprise cellular protection against oxidative stress, modulation of intracellular signaling cascades that apply hydrogen peroxide as a second messenger molecule, and regulation of cell proliferation. In the present review, we discuss pertinent findings on the protein structure, the cell- and tissue-specific distribution, as well as the subcellular localization of Prxs. A particular emphasis is put on Prx I, which is the most abundant and ubiquitously distributed member of the mammalian Prxs. Major transcriptional and posttranslational regulatory mechanisms and signaling pathways that control Prx gene expression and activity are summarized. The interaction of Prx I with the oncogene products c-Abl and c-Myc and the regulatory role of Prx I for cell proliferation and apoptosis are highlighted. Recent findings on phenotypical alterations of mouse models with targeted disruptions of Prx genes are discussed, confirming the physiological functions of Prxs for antioxidant cell and tissue protection along with an important role as tumor suppressors.

  17. Cell Wall Metabolism in Response to Abiotic Stress

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    Hyacinthe Le Gall

    2015-02-01

    Full Text Available This review focuses on the responses of the plant cell wall to several abiotic stresses including drought, flooding, heat, cold, salt, heavy metals, light, and air pollutants. The effects of stress on cell wall metabolism are discussed at the physiological (morphogenic, transcriptomic, proteomic and biochemical levels. The analysis of a large set of data shows that the plant response is highly complex. The overall effects of most abiotic stress are often dependent on the plant species, the genotype, the age of the plant, the timing of the stress application, and the intensity of this stress. This shows the difficulty of identifying a common pattern of stress response in cell wall architecture that could enable adaptation and/or resistance to abiotic stress. However, in most cases, two main mechanisms can be highlighted: (i an increased level in xyloglucan endotransglucosylase/hydrolase (XTH and expansin proteins, associated with an increase in the degree of rhamnogalacturonan I branching that maintains cell wall plasticity and (ii an increased cell wall thickening by reinforcement of the secondary wall with hemicellulose and lignin deposition. Taken together, these results show the need to undertake large-scale analyses, using multidisciplinary approaches, to unravel the consequences of stress on the cell wall. This will help identify the key components that could be targeted to improve biomass production under stress conditions.

  18. Bridges between mitochondrial oxidative stress, ER stress and mTOR signaling in pancreatic β cells.

    Science.gov (United States)

    Wang, Jing; Yang, Xin; Zhang, Jingjing

    2016-08-01

    Pancreatic β cell dysfunction, i.e., failure to provide insulin in concentrations sufficient to control blood sugar, is central to the etiology of all types of diabetes. Current evidence implicates mitochondrial oxidative stress and endoplasmic reticulum (ER) stress in pancreatic β cell loss and impaired insulin secretion. Oxidative and ER stress are interconnected so that misfolded proteins induce reactive oxygen species (ROS) production; likewise, oxidative stress disturbs the ER redox state thereby disrupting correct disulfide bond formation and proper protein folding. mTOR signaling regulates many metabolic processes including protein synthesis, cell growth, survival and proliferation. Oxidative stress inhibits mTORC1, which is considered an important suppressor of mitochondrial oxidative stress in β cells, and ultimately, controls cell survival. The interplay between ER stress and mTORC1 is complicated, since the unfolded protein response (UPR) activation can occur upstream or downstream of mTORC1. Persistent activation of mTORC1 initiates protein synthesis and UPR activation, while in the later phase induces ER stress. Chronic activation of ER stress inhibits Akt/mTORC1 pathway, while under particular settings, acute activation of UPR activates Akt-mTOR signaling. Thus, modulating mitochondrial oxidative stress and ER stress via mTOR signaling may be an approach that will effectively suppress obesity- or glucolipotoxicity-induced metabolic disorders such as insulin resistance and type 2 diabetes mellitus (T2DM). In this review, we focus on the regulations between mTOR signaling and mitochondrial oxidative or ER stress in pancreatic β cells. PMID:27185188

  19. Optimal matrix rigidity for stress fiber polarization in stem cells

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    Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.

    2010-01-01

    The shape and differentiation of human mesenchymal stem cells is especially sensitive to the rigidity of their environment; the physical mechanisms involved are unknown. A theoretical model and experiments demonstrate here that the polarization/alignment of stress-fibers within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix whose polarizability, unlike dead matter, depends on the feedback of cellular forces that develop in response to matrix stresses. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress-fibers parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress-fibers in stem cells. These findings offer a first physical insight for the dependence of stem cell differentiation on tissue elasticity. PMID:20563235

  20. Cell cycle control, checkpoint mechanisms, and genotoxic stress.

    OpenAIRE

    R.E. Shackelford; Kaufmann, W K; Paules, R S

    1999-01-01

    The ability of cells to maintain genomic integrity is vital for cell survival and proliferation. Lack of fidelity in DNA replication and maintenance can result in deleterious mutations leading to cell death or, in multicellular organisms, cancer. The purpose of this review is to discuss the known signal transduction pathways that regulate cell cycle progression and the mechanisms cells employ to insure DNA stability in the face of genotoxic stress. In particular, we focus on mammalian cell cy...

  1. Oxidative stress induces mitochondrial fragmentation in frataxin-deficient cells

    International Nuclear Information System (INIS)

    Highlights: ► Yeast frataxin-deficiency leads to increased proportion of fragmented mitochondria. ► Oxidative stress induces complete mitochondrial fragmentation in Δyfh1 cells. ► Oxidative stress increases mitochondrial fragmentation in patient fibroblasts. ► Inhibition of mitochondrial fission in Δyfh1 induces oxidative stress resistance. -- Abstract: Friedreich ataxia (FA) is the most common recessive neurodegenerative disease. It is caused by deficiency in mitochondrial frataxin, which participates in iron–sulfur cluster assembly. Yeast cells lacking frataxin (Δyfh1 mutant) showed an increased proportion of fragmented mitochondria compared to wild-type. In addition, oxidative stress induced complete fragmentation of mitochondria in Δyfh1 cells. Genetically controlled inhibition of mitochondrial fission in these cells led to increased resistance to oxidative stress. Here we present evidence that in yeast frataxin-deficiency interferes with mitochondrial dynamics, which might therefore be relevant for the pathophysiology of FA.

  2. Effects of Fluid Shear Stress on Cancer Stem Cell Viability

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    Sunday, Brittney; Triantafillu, Ursula; Domier, Ria; Kim, Yonghyun

    2014-11-01

    Cancer stem cells (CSCs), which are believed to be the source of tumor formation, are exposed to fluid shear stress as a result of blood flow within the blood vessels. It was theorized that CSCs would be less susceptible to cell death than non-CSCs after both types of cell were exposed to a fluid shear stress, and that higher levels of fluid shear stress would result in lower levels of cell viability for both cell types. To test this hypothesis, U87 glioblastoma cells were cultured adherently (containing smaller populations of CSCs) and spherically (containing larger populations of CSCs). They were exposed to fluid shear stress in a simulated blood flow through a 125-micrometer diameter polyetheretherketone (PEEK) tubing using a syringe pump. After exposure, cell viability data was collected using a BioRad TC20 Automated Cell Counter. Each cell type was tested at three physiological shear stress values: 5, 20, and 60 dynes per centimeter squared. In general, it was found that the CSC-enriched U87 sphere cells had higher cell viability than the CSC-depleted U87 adherent cancer cells. Interestingly, it was also observed that the cell viability was not negatively affected by the higher fluid shear stress values in the tested range. In future follow-up studies, higher shear stresses will be tested. Furthermore, CSCs from different tumor origins (e.g. breast tumor, prostate tumor) will be tested to determine cell-specific shear sensitivity. National Science Foundation Grant #1358991 supported the first author as an REU student.

  3. Mechanical Stress Promotes Cisplatin-Induced Hepatocellular Carcinoma Cell Death

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    Laila Ziko

    2015-01-01

    Full Text Available Cisplatin (CisPt is a commonly used platinum-based chemotherapeutic agent. Its efficacy is limited due to drug resistance and multiple side effects, thereby warranting a new approach to improving the pharmacological effect of CisPt. A newly developed mathematical hypothesis suggested that mechanical loading, when coupled with a chemotherapeutic drug such as CisPt and immune cells, would boost tumor cell death. The current study investigated the aforementioned mathematical hypothesis by exposing human hepatocellular liver carcinoma (HepG2 cells to CisPt, peripheral blood mononuclear cells, and mechanical stress individually and in combination. HepG2 cells were also treated with a mixture of CisPt and carnosine with and without mechanical stress to examine one possible mechanism employed by mechanical stress to enhance CisPt effects. Carnosine is a dipeptide that reportedly sequesters platinum-based drugs away from their pharmacological target-site. Mechanical stress was achieved using an orbital shaker that produced 300 rpm with a horizontal circular motion. Our results demonstrated that mechanical stress promoted CisPt-induced death of HepG2 cells (~35% more cell death. Moreover, results showed that CisPt-induced death was compromised when CisPt was left to mix with carnosine 24 hours preceding treatment. Mechanical stress, however, ameliorated cell death (20% more cell death.

  4. Mechanistic insights into aging, cell cycle progression, and stress response

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    Troy Anthony Alan Harkness

    2012-06-01

    Full Text Available The longevity of an organism depends on the health of its cells. Throughout life cells are exposed to numerous intrinsic and extrinsic stresses, such as free radicals, generated through mitochondrial electron transport, and ultraviolet irradiation. The cell has evolved numerous mechanisms to scavenge free radicals and repair damage induced by these insults. One mechanism employed by the yeast Saccharomyces cerevisiae to combat stress utilizes the Anaphase Promoting Complex (APC, an essential multi-subunit ubiquitin-protein ligase structurally and functionally conserved from yeast to humans that controls progression through mitosis and G1. We have observed that yeast cells expressing compromised APC subunits are sensitive to multiple stresses and have shorter replicative and chronological lifespans. In a pathway that runs parallel to that regulated by the APC, members of the Forkhead box (Fox transcription factor family also regulate stress responses. The yeast Fox orthologues Fkh1 and Fkh2 appear to drive the transcription of stress response factors and slow early G1 progression, while the APC seems to regulate chromatin structure, chromosome segregation, and resetting of the transcriptome in early G1. In contrast, under non-stress conditions, the Fkhs play a complex role in cell cycle progression, partially through activation of the APC. Direct and indirect interactions between the APC and the yeast Fkhs appear to be pivotal for lifespan determination. Here we explore the potential for these interactions to be evolutionarily conserved as a mechanism to balance cell cycle regulation with stress responses.

  5. Time to Relax: Mechanical Stress Release Guides Stem Cell Responses.

    Science.gov (United States)

    Sommerfeld, Sven D; Elisseeff, Jennifer H

    2016-02-01

    Stem cells integrate spatiotemporal cues, including the mechanical properties of their microenvironment, into their fate decisions. Chaudhuri et al. (2015) show that the ability of the extracellular matrix to dissipate cell-induced forces, referred to as stress-relaxation, is a key mechanical signal influencing stem cell fate and function. PMID:26849301

  6. Insulinorésistance et stress oxydant dans le syndrome métabolique : étude expérimentale des effets protecteurs de microconstituants nutritionnels (Polyphénols du thé, de la cannelle et chrome III)

    OpenAIRE

    Benaraba, Rachida

    2007-01-01

    The incidence of the metabolic syndrome is increasing in Western countries, leading to high risks of diabetes and cardiovascular diseases. Considering the relationship between insulin resistance and oxidative stress, which are present in the metabolic syndrome, we hypothesized that microconstituants, potentially antioxidant and insulin sensitizers, could be of interest in nutritional prevention of the metabolic syndrome. We focused on green tea extracts, cinnamon extracts, and Chromium III. I...

  7. Oxidative Stress Induces Senescence in Cultured RPE Cells.

    Science.gov (United States)

    Aryan, Nona; Betts-Obregon, Brandi S; Perry, George; Tsin, Andrew T

    2016-01-01

    The aim of this research is to determine whether oxidative stress induces cellular senescence in human retinal pigment epithelial cells. Cultured ARPE19 cells were subjected to different concentrations of hydrogen peroxide to induce oxidative stress. Cells were seeded into 24-well plates with hydrogen peroxide added to cell medium and incubated at 37°C + 5% CO2 for a 90-minute period [at 0, 300, 400 and 800 micromolar (MCM) hydrogen peroxide]. The number of viable ARPE19 cells were recorded using the Trypan Blue Dye Exclusion Method and cell senescence was measured by positive staining for senescence-associated beta-galactosidase (SA-beta-Gal) protein. Without hydrogen peroxide treatment, the number of viable ARPE19 cells increased significantly from 50,000 cells/well to 197,000 within 72 hours. Treatment with hydrogen peroxide reduced this level of cell proliferation significantly (to 52,167 cells at 400 MCM; to 49,263 cells at 800 MCM). Meanwhile, cells with a high level of positive senescence-indicator SA-Beta-Gal-positive staining was induced by hydrogen peroxide treatment (from a baseline level of 12% to 80% at 400 MCM and at 800 MCM). Our data suggests that oxidative stress from hydrogen peroxide treatment inhibited ARPE19 cell proliferation and induced cellular senescence. PMID:27651846

  8. Effects of Oxidative Stress on Mesenchymal Stem Cell Biology

    Science.gov (United States)

    2016-01-01

    Mesenchymal stromal/stem cells (MSCs) are multipotent stem cells present in most fetal and adult tissues. Ex vivo culture-expanded MSCs are being investigated for tissue repair and immune modulation, but their full clinical potential is far from realization. Here we review the role of oxidative stress in MSC biology, as their longevity and functions are affected by oxidative stress. In general, increased reactive oxygen species (ROS) inhibit MSC proliferation, increase senescence, enhance adipogenic but reduce osteogenic differentiation, and inhibit MSC immunomodulation. Furthermore, aging, senescence, and oxidative stress reduce their ex vivo expansion, which is critical for their clinical applications. Modulation of sirtuin expression and activity may represent a method to reduce oxidative stress in MSCs. These findings have important implications in the clinical utility of MSCs for degenerative and immunological based conditions. Further study of oxidative stress in MSCs is imperative in order to enhance MSC ex vivo expansion and in vivo engraftment, function, and longevity. PMID:27413419

  9. Oxidative stress induces senescence in human mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, Anita [Department of Anesthesiology, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Meyer, Matthias; Bechmann, Volker [Department of Trauma Surgery, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Nerlich, Michael [Department of Anesthesiology, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany); Angele, Peter, E-mail: Peter.Angele@klinik.uni-regensburg.de [Department of Trauma Surgery, University Medical Center Regensburg, Franz-Josef-Strauss-Allee 11, 93042 Regensburg (Germany)

    2011-07-01

    Mesenchymal stem cells (MSCs) contribute to tissue repair in vivo and form an attractive cell source for tissue engineering. Their regenerative potential is impaired by cellular senescence. The effects of oxidative stress on MSCs are still unknown. Our studies were to investigate into the proliferation potential, cytological features and the telomere linked stress response system of MSCs, subject to acute or prolonged oxidant challenge with hydrogen peroxide. Telomere length was measured using the telomere restriction fragment assay, gene expression was determined by rtPCR. Sub-lethal doses of oxidative stress reduced proliferation rates and induced senescent-morphological features and senescence-associated {beta}-galactosidase positivity. Prolonged low dose treatment with hydrogen peroxide had no effects on cell proliferation or morphology. Sub-lethal and prolonged low doses of oxidative stress considerably accelerated telomere attrition. Following acute oxidant insult p21 was up-regulated prior to returning to initial levels. TRF1 was significantly reduced, TRF2 showed a slight up-regulation. SIRT1 and XRCC5 were up-regulated after oxidant insult and expression levels increased in aging cells. Compared to fibroblasts and chondrocytes, MSCs showed an increased tolerance to oxidative stress regarding proliferation, telomere biology and gene expression with an impaired stress tolerance in aged cells.

  10. Stressful Presentations: Mild Chronic Cold Stress in Mice Influences Baseline Properties of Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Kathleen Marie Kokolus

    2014-02-01

    Full Text Available The ability of dendritic cells to stimulate and regulate T cells is critical to effective anti-tumor immunity. Therefore, it is important to fully recognize any inherent factors which may influence DC function under experimental conditions, especially in laboratory mice since they are used so heavily to study immune responses. Physiological stress is well recognized to impair several arms of immune protection. The goals of this report are to briefly summarize previous work revealing how DCs respond to various forms of physiologically relevant stress and to present new data highlighting the potential for chronic mild cold stress inherent in mice housed at standard ambient temperatures required for laboratory mice to influence baseline DCs properties. Since recent data from our group shows that CD8+ T cell function is altered by mild chronic cold stress and since DC function is crucial for CD8+ T cell activation, we wondered whether mild cold stress may also be influencing DC properties. We found increased numbers of splenic DCs (CD11c+ in cold stressed mice compared to mice housed at a thermoneutral temperature, which significantly reduces cold stress. However, many of the DCs which are expanded in cold stressed mice express an immature phenotype. We also found that antigen presentation and ability of splenocytes to activate T cells were impaired compared to that seen in DCs isolated from mice at thermoneutrality. The new data presented here strongly suggest that the housing temperature of mice can affect fundamental properties of DC function which in turn could be influencing the response of DCs to added experimental stressors or other treatments.

  11. Fluid shear stress modulation of hepatocyte-like cell function.

    Science.gov (United States)

    Rashidi, Hassan; Alhaque, Sharmin; Szkolnicka, Dagmara; Flint, Oliver; Hay, David C

    2016-07-01

    Freshly isolated human adult hepatocytes are considered to be the gold standard tool for in vitro studies. However, primary hepatocyte scarcity, cell cycle arrest and the rapid loss of cell phenotype limit their widespread deployment. Human embryonic stem cells and induced pluripotent stem cells provide renewable sources of hepatocyte-like cells (HLCs). Despite the use of various differentiation methodologies, HLCs like primary human hepatocytes exhibit unstable phenotype in culture. It has been shown that the functional capacity can be improved by adding back elements of human physiology, such as cell co-culture or through the use of natural and/or synthetic surfaces. In this study, the effect of fluid shear stress on HLC performance was investigated. We studied two important liver functions, cytochrome P450 drug metabolism and serum protein secretion, in static cultures and those exposed to fluid shear stress. Our study demonstrates that fluid shear stress improved Cyp1A2 activity by approximately fivefold. This was paralleled by an approximate ninefold increase in sensitivity to a drug, primarily metabolised by Cyp2D6. In addition to metabolic capacity, fluid shear stress also improved hepatocyte phenotype with an approximate fourfold reduction in the secretion of a foetal marker, alpha-fetoprotein. We believe these studies highlight the importance of introducing physiologic cues in cell-based models to improve somatic cell phenotype. PMID:26979076

  12. Epidermal stem cells response to radiative genotoxic stress

    International Nuclear Information System (INIS)

    Human skin is the first organ exposed to various environmental stresses, which requires the development by skin stem cells of specific mechanisms to protect themselves and to ensure tissue homeostasis. As stem cells are responsible for the maintenance of epidermis during individual lifetime, the preservation of genomic integrity in these cells is essential. My PhD aimed at exploring the mechanisms set up by epidermal stem cells in order to protect themselves from two genotoxic stresses, ionizing radiation (Gamma Rays) and ultraviolet radiation (UVB). To begin my PhD, I have taken part of the demonstration of protective mechanisms used by keratinocyte stem cells after ionizing radiation. It has been shown that these cells are able to rapidly repair most types of radiation-induced DNA damage. Furthermore, we demonstrated that this repair is activated by the fibroblast growth factor 2 (FGF2). In order to know if this protective mechanism is also operating in cutaneous carcinoma stem cells, we investigated the response to gamma Rays of carcinoma stem cells isolated from a human carcinoma cell line. As in normal keratinocyte stem cells, we demonstrated that cancer stem cells could rapidly repair radio-induced DNA damage. Furthermore, fibroblast growth factor 2 also mediates this repair, notably thanks to its nuclear isoforms. The second project of my PhD was to study human epidermal stem cells and progenitors responses to UVB radiation. Once cytometry and irradiation conditions were set up, the toxicity of UVB radiation has been evaluate in the primary cell model. We then characterized UVB photons effects on cell viability, proliferation and repair of DNA damage. This study allowed us to bring out that responses of stem cells and their progeny to UVB are different, notably at the level of part of their repair activity of DNA damage. Moreover, progenitors and stem cells transcriptomic responses after UVB irradiation have been study in order to analyze the global

  13. Salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA

    OpenAIRE

    Qiuqiang Gao; Liang-Chun Liou; Qun Ren; Xiaoming Bao; Zhaojie Zhang

    2015-01-01

    The yeast cell wall plays an important role in maintaining cell morphology, cell integrity and response to environmental stresses. Here, we report that salt stress causes cell wall damage in yeast cells lacking mitochondrial DNA (ρ0). Upon salt treatment, the cell wall is thickened, broken and becomes more sensitive to the cell wall-perturbing agent sodium dodecyl sulfate (SDS). Also, SCW11 mRNA levels are elevated in ρ0 cells. Deletion of SCW11 significantly decreases the sensitivity of ρ0 c...

  14. Effect of salt hyperosmotic stress on yeast cell viability

    Directory of Open Access Journals (Sweden)

    Logothetis Stelios

    2007-01-01

    Full Text Available During fermentation for ethanol production, yeasts are subjected to different kinds of physico-chemical stresses such as: initially high sugar concentration and low temperature; and later, increased ethanol concentrations. Such conditions trigger a series of biological responses in an effort to maintain cell cycle progress and yeast cell viability. Regarding osmostress, many studies have been focused on transcriptional activation and gene expression in laboratory strains of Saccharomyces cerevisiae. The overall aim of this present work was to further our understanding of wine yeast performance during fermentations under osmotic stress conditions. Specifically, the research work focused on the evaluation of NaCl-induced stress responses of an industrial wine yeast strain S. cerevisiae (VIN 13, particularly with regard to yeast cell growth and viability. The hypothesis was that osmostress conditions energized specific genes to enable yeast cells to survive under stressful conditions. Experiments were designed by pretreating cells with different sodium chloride concentrations (NaCl: 4%, 6% and 10% w/v growing in defined media containing D-glucose and evaluating the impact of this on yeast growth and viability. Subsequent fermentation cycles took place with increasing concentrations of D-glucose (20%, 30%, 40% w/v using salt-adapted cells as inocula. We present evidence that osmostress induced by mild salt pre-treatments resulted in beneficial influences on both cell viability and fermentation performance of an industrial wine yeast strain.

  15. Orientational Polarizability and Stress Response of Biological Cells

    Science.gov (United States)

    Safran, S. A.; de, R.; Zemel, A.

    We present a theoretical treatment of the orientational response to external stress of active, contractile cells embedded in a gel-like elastic medium. The theory includes random forces as well as forces that arise from the deformation of the matrix and those due to the internal regulation of the stress fibers and focal adhesions of the cell. We calculate both the static and high frequency limits of the orientational response in terms of the cellular polarizability. For systems in which the forces due to regulation and activity dominate the mechanical forces, we show that there is a non-linear dynamical response which, in the high frequency limit, causes the cell to orient nearly perpendicular to the direction of the applied stress.

  16. Oxidative stress induces mitochondrial fragmentation in frataxin-deficient cells

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, Sophie [Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod, CNRS-Universite Paris-Diderot, Sorbonne Paris Cite, 15 rue Helene Brion, 75205 Paris cedex 13 (France); ED515 UPMC, 4 place Jussieu 75005 Paris (France); Sliwa, Dominika [Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod, CNRS-Universite Paris-Diderot, Sorbonne Paris Cite, 15 rue Helene Brion, 75205 Paris cedex 13 (France); Rustin, Pierre [Inserm, U676, Physiopathology and Therapy of Mitochondrial Disease Laboratory, 75019 Paris (France); Universite Paris-Diderot, Faculte de Medecine Denis Diderot, IFR02 Paris (France); Camadro, Jean-Michel [Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod, CNRS-Universite Paris-Diderot, Sorbonne Paris Cite, 15 rue Helene Brion, 75205 Paris cedex 13 (France); Santos, Renata, E-mail: santos.renata@ijm.univ-paris-diderot.fr [Mitochondria, Metals and Oxidative Stress Laboratory, Institut Jacques Monod, CNRS-Universite Paris-Diderot, Sorbonne Paris Cite, 15 rue Helene Brion, 75205 Paris cedex 13 (France)

    2012-02-10

    Highlights: Black-Right-Pointing-Pointer Yeast frataxin-deficiency leads to increased proportion of fragmented mitochondria. Black-Right-Pointing-Pointer Oxidative stress induces complete mitochondrial fragmentation in {Delta}yfh1 cells. Black-Right-Pointing-Pointer Oxidative stress increases mitochondrial fragmentation in patient fibroblasts. Black-Right-Pointing-Pointer Inhibition of mitochondrial fission in {Delta}yfh1 induces oxidative stress resistance. -- Abstract: Friedreich ataxia (FA) is the most common recessive neurodegenerative disease. It is caused by deficiency in mitochondrial frataxin, which participates in iron-sulfur cluster assembly. Yeast cells lacking frataxin ({Delta}yfh1 mutant) showed an increased proportion of fragmented mitochondria compared to wild-type. In addition, oxidative stress induced complete fragmentation of mitochondria in {Delta}yfh1 cells. Genetically controlled inhibition of mitochondrial fission in these cells led to increased resistance to oxidative stress. Here we present evidence that in yeast frataxin-deficiency interferes with mitochondrial dynamics, which might therefore be relevant for the pathophysiology of FA.

  17. Cocoa Phenolic Extract Protects Pancreatic Beta Cells against Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Laura Bravo

    2013-07-01

    Full Text Available Diabetes mellitus is associated with reductions in glutathione, supporting the critical role of oxidative stress in its pathogenesis. Antioxidant food components such as flavonoids have a protective role against oxidative stress-induced degenerative and age-related diseases. Flavonoids constitute an important part of the human diet; they can be found in most plant foods, including green tea, grapes or cocoa and possess multiple biological activities. This study investigates the chemo-protective effect of a cocoa phenolic extract (CPE containing mainly flavonoids against oxidative stress induced by tert-butylhydroperoxide (t-BOOH on Ins-1E pancreatic beta cells. Cell viability and oxidative status were evaluated. Ins-1E cells treatment with 5–20 μg/mL CPE for 20 h evoked no cell damage and did not alter ROS production. Addition of 50 μM t-BOOH for 2 h increased ROS and carbonyl groups content and decreased reduced glutathione level. Pre-treatment of cells with CPE significantly prevented the t-BOOH-induced ROS and carbonyl groups and returned antioxidant defences to adequate levels. Thus, Ins-1E cells treated with CPE showed a remarkable recovery of cell viability damaged by t-BOOH, indicating that integrity of surviving machineries in the CPE-treated cells was notably protected against the oxidative insult.

  18. Cell proliferation alterations in Chlorella cells under stress conditions

    International Nuclear Information System (INIS)

    Very little is known about growth and proliferation in relation to the cell cycle regulation of algae. The lack of knowledge is even greater when referring to the potential toxic effects of pollutants on microalgal cell division. To assess the effect of terbutryn, a triazine herbicide, on the proliferation of the freshwater microalga Chlorella vulgaris three flow cytometric approaches were used: (1) in vivo cell division using 5-,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) staining was measured, (2) the growth kinetics were determined by cytometric cell counting and (3) cell viability was evaluated with the membrane-impermeable double-stranded nucleic acid stain propidium iodide (PI). The results obtained in the growth kinetics study using CFSE to identify the microalgal cell progeny were consistent with those determined by cytometric cell counting. In all C. vulgaris cultures, each mother cell had undergone only one round of division through the 96 h of assay and the cell division occurred during the dark period. Cell division of the cultures exposed to the herbicide was asynchronous. Terbutryn altered the normal number of daughter cells (4 autospores) obtained from each mother cell. The number was only two in the cultures treated with 250 nM. The duration of the lag phase after the exposure to terbutryn could be dependent on the existence of a critical cell size to activate cytoplasmic division. Cell size, complexity and fluorescence of chlorophyll a of the microalgal cells presented a marked light/dark (day/night) cycle, except in the non-dividing 500 nM cultures, where terbutryn arrested cell division at the beginning of the cycle. Viability results showed that terbutryn has an algastatic effect in C. vulgaris cells at this concentration. The rapid and precise determination of cell proliferation by CFSE staining has allowed us to develop a model for assessing both the cell cycle of C. vulgaris and the in vivo effects of pollutants on growth and

  19. Cell proliferation alterations in Chlorella cells under stress conditions

    Energy Technology Data Exchange (ETDEWEB)

    Rioboo, Carmen [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n, 15008 A Coruna (Spain); O' Connor, Jose Enrique [Laboratorio de Citomica, Unidad Mixta de Investigacion CIPF-UVEG, Centro de Investigacion Principe Felipe, Avda. Autopista del Saler, 16, 46013 Valencia (Spain); Prado, Raquel; Herrero, Concepcion [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n, 15008 A Coruna (Spain); Cid, Angeles, E-mail: cid@udc.es [Laboratorio de Microbiologia, Facultad de Ciencias, Universidad de A Coruna, Campus da Zapateira s/n, 15008 A Coruna (Spain)

    2009-09-14

    Very little is known about growth and proliferation in relation to the cell cycle regulation of algae. The lack of knowledge is even greater when referring to the potential toxic effects of pollutants on microalgal cell division. To assess the effect of terbutryn, a triazine herbicide, on the proliferation of the freshwater microalga Chlorella vulgaris three flow cytometric approaches were used: (1) in vivo cell division using 5-,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) staining was measured, (2) the growth kinetics were determined by cytometric cell counting and (3) cell viability was evaluated with the membrane-impermeable double-stranded nucleic acid stain propidium iodide (PI). The results obtained in the growth kinetics study using CFSE to identify the microalgal cell progeny were consistent with those determined by cytometric cell counting. In all C. vulgaris cultures, each mother cell had undergone only one round of division through the 96 h of assay and the cell division occurred during the dark period. Cell division of the cultures exposed to the herbicide was asynchronous. Terbutryn altered the normal number of daughter cells (4 autospores) obtained from each mother cell. The number was only two in the cultures treated with 250 nM. The duration of the lag phase after the exposure to terbutryn could be dependent on the existence of a critical cell size to activate cytoplasmic division. Cell size, complexity and fluorescence of chlorophyll a of the microalgal cells presented a marked light/dark (day/night) cycle, except in the non-dividing 500 nM cultures, where terbutryn arrested cell division at the beginning of the cycle. Viability results showed that terbutryn has an algastatic effect in C. vulgaris cells at this concentration. The rapid and precise determination of cell proliferation by CFSE staining has allowed us to develop a model for assessing both the cell cycle of C. vulgaris and the in vivo effects of pollutants on growth and

  20. Film stresses and electrode buckling in organic solar cells

    KAUST Repository

    Brand, Vitali

    2012-08-01

    We investigate the film stresses that develop in the polymer films and metal electrodes of poly(3-hexyl thiophene) (P3HT) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) bulk heterojunction (BHJ) organic solar cells. A compressive biaxial stress of ∼-36 MPa was measured in PEDOT:PSS while a tensile stress of ∼6 MPa was measured in the BHJ layer. We then analyze the effect of electrode deposition rate on the film stresses in the Al electrode. Compressive stresses of ∼-100 to -145 MPa in the Al electrode lead to a buckling instability resulting in undulating electrode surface topography. The BHJ layer was found to have the lowest cohesion (∼1.5-1.8 J/m 2) among the layers of the solar cell and dependent on the Al electrode deposition rate. The cohesive failure path in the BHJ layer exhibited the same periodicity and orientation of the Al electrode buckling topography. We discuss the implications of the film stresses on damage processes during device fabrication and operation. © 2012 Elsevier B.V. All rights reserved.

  1. Nutritional stress enhances cell viability of odontoblast-like cells subjected to low level laser irradiation

    International Nuclear Information System (INIS)

    In spite of knowing that cells under stress are biostimulated by low level laser (LLL) irradiation, the ideal condition of stress to different cell lines has not yet been established. Consequently, the aim of the present in vitro study was to evaluate the effects of a defined parameter of LLL irradiation applied on stressed odontoblast-like pulp cells (MDPC-23). The cells were seeded (12500 cells/cm2) in wells of 24-well plates using complete culture medium (DMEM) and incubated for 24 hours. Then, the DMEM was replaced by a new medium with low concentrations (nutritional stress condition) of fetal bovine serum (FBS) giving rise to the following experimental groups: G1: 2% FBS; G2: 5% FBS; and G3: 10% FBS. The cells were irradiated three times with LLL in specific parameters (808±3 nm, 100 mW, 1.5 J/cm2) every 24 hours. No irradiation was carried out in groups G4 (2% FBS-Control), G5 (5% FBS-Control), and G6 (10% FBS-Control). For all groups, the cell metabolism (MTT assay) and morphology (SEM) was evaluated. The experimental groups showed enhanced cell metabolism and normal cell morphology regardless of FBS concentration. A slight increase in the cell metabolism was observed only in group G2. It was concluded that cell nutritional stress caused by reducing the concentration of FBS to 5% is the most suitable method to assess the biostimulation of LLL irradiated MDPC-23 cells

  2. Cell wall remodelling enzymes modulate fungal cell wall elasticity and osmotic stress resistance

    OpenAIRE

    Ene, Iuliana; Walker, Louise; Schiavone, Marion; Lee, Keunsook K.; Dague, Etienne; Gow, Neil A.R.; Munro, Carol A

    2015-01-01

    The fungal cell wall confers cell morphology and protection against environmental insults. For fungal pathogens, the cell wall is a key immunological modulator and an ideal therapeutic target. Yeast cell walls possess an inner matrix of interlinked β-glucan and chitin that is thought to provide tensile strength and rigidity. Yeast cells remodel their walls over time in response to environmental change, a process controlled by evolutionarily conserved stress (Hog1) and cell integrity (Mkc1, Ce...

  3. Shear stress-induced improvement of red blood cell deformability

    OpenAIRE

    Meram, Ece; Yılmaz, Bahar D.; Bas, Ceren; Atac, Nazlı; Yalçın, Ö.; Başkurt, Oguz K.; Meiselman, Herbert J.

    2013-01-01

    Classically, it is known that red blood cell (RBC) deformability is determined by the geometric and material properties of these cells. Experimental evidence accumulated during the last decade has introduced the concept of active regulation of RBC deformability. This regulation is mainly related to altered associations between membrane skeletal proteins and integral proteins, with the latter serving to anchor the skeleton to the lipid matrix. It has been hypothesized that shear stress induces...

  4. Magnetite induces oxidative stress and apoptosis in lung epithelial cells.

    Science.gov (United States)

    Ramesh, Vani; Ravichandran, Prabakaran; Copeland, Clinton L; Gopikrishnan, Ramya; Biradar, Santhoshkumar; Goornavar, Virupaxi; Ramesh, Govindarajan T; Hall, Joseph C

    2012-04-01

    There is an ongoing concern regarding the biocompatibility of nanoparticles with sizes less than 100 nm as compared to larger particles of the same nominal substance. In this study, we investigated the toxic properties of magnetite stabilized with polyacrylate sodium. The magnetite was characterized by X-ray powder diffraction analysis, and the mean particle diameter was calculated using the Scherrer formula and was found to be 9.3 nm. In this study, we treated lung epithelial cells with different concentrations of magnetite and investigated their effects on oxidative stress and cell proliferation. Our data showed an inhibition of cell proliferation in magnetite-treated cells with a significant dose-dependent activation and induction of reactive oxygen species. Also, we observed a depletion of antioxidants, glutathione, and superoxide dismutase, respectively, as compared with control cells. In addition, apoptotic-related protease/enzyme such as caspase-3 and -8 activities, were increased in a dose-dependent manner with corresponding increased levels of DNA fragmentation in magnetite-treated cells compared to than control cells. Together, the present study reveals that magnetite exposure induces oxidative stress and depletes antioxidant levels in the cells to stimulate apoptotic pathway for cell death. PMID:22147200

  5. Stress-induced adaptive islet cell identity changes.

    Science.gov (United States)

    Cigliola, V; Thorel, F; Chera, S; Herrera, P L

    2016-09-01

    The different forms of diabetes mellitus differ in their pathogenesis but, ultimately, they are all characterized by progressive islet β-cell loss. Restoring the β-cell mass is therefore a major goal for future therapeutic approaches. The number of β-cells found at birth is determined by proliferation and differentiation of pancreatic progenitor cells, and it has been considered to remain mostly unchanged throughout adult life. Recent studies in mice have revealed an unexpected plasticity in islet endocrine cells in response to stress; under certain conditions, islet non-β-cells have the potential to reprogram into insulin producers, thus contributing to restore the β-cell mass. Here, we discuss the latest findings on pancreas and islet cell plasticity upon physiological, pathological and experimental conditions of stress. Understanding the mechanisms involved in cell reprogramming in these models will allow the development of new strategies for the treatment of diabetes, by exploiting the intrinsic regeneration capacity of the pancreas. PMID:27615136

  6. Stress-mediated p38 activation promotes somatic cell reprogramming

    Institute of Scientific and Technical Information of China (English)

    Xinxiu Xu; Quan Wang; Yuan Long; Ru Zhang; Xiaoyuan Wei; Mingzhe Xing; Haifeng Gu

    2013-01-01

    Environmental stress-mediated adaptation plays essential roles in the evolution of life.Cellular adaptation mechanisms usually involve the regulation of chromatin structure,transcription,mRNA stability and translation,which eventually lead to efficient changes in gene expression.Global epigenetic change is also involved in the reprogramming of somatic cells into induced pluripotent stem (iPS) cells by defined factors.Here we report that environmental stress such as hyperosmosis not only facilitates four factor-mediated reprogramming,but also enhances two or one factor-induced iPS cell generation.Hyperosmosis-induced p38 activation plays a critical role in this process.Constitutive active p38 mimics the positive effect of hyperosmosis,while dominant negative p38 and p38 inhibitor block the effect of hyperosmosis.Further study indicates stress-mediated p38 activation may promote reprogramming by reducing the global DNA methylation level and enhancing the expression of pluripotency genes.Our results demonstrate how simple environmental stress like hyperosmosis helps to alter the fate of cells via intracellular signaling and epigenetic modulation.

  7. High glucose augments stress-induced apoptosis in endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Wenwen Zhong; Yang Liu; Hui Tian

    2009-01-01

    Hyperglycemia has been identified as one of the important factors involved in the microvascular complications of diabetes, and has been related to increased cardiovascular mortality. Endothelial damage and dysfunction result from diabetes; therefore, the aim of this study was to determine the response of endothelial cells to stressful stimuli, modelled in normal and high glucose concentrations in vitro. Eahy 926 endothelial cells were cultured in 5 mmol/L or 30 mmol/L glucose conditions for a 24 hour period and oxidative stress was induced by exposure to hydrogen peroxide (H2O2) or tumour necrosis factor- α (TNF- α ), following which the protective effect of the glucocorticoid dexamethasone was assessed. Apoptosis, necrosis and cell viability were determined using an ELISA for DNA fragmentation, an enzymatic lactate dehydrogenase assay and an MTT assay, respectively. High glucose significantly increased the susceptibility of Eahy 926 cells to apoptosis in the presence of 500 μmol/L H2O2, above that induced in normal glucose (P<0.02). A reduction of H2O2- and TNF- α -induced apoptosis occurred in both high and low glucose after treatment with dexametha-sone (P<0.05). Conclusion high glucose is effective in significantly augmenting stress caused by H2O2, but not in causing stress alone. These findings suggest a mechanism by which short term hyperglycemia may facilitate and augment endothelial damage.

  8. Kinetic study of the alkaline metals oxidation by dry oxygen; Etude cinetique de l'oxydation des metaux alcalins par l'oxygene sec

    Energy Technology Data Exchange (ETDEWEB)

    Touzain, Ph. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-06-15

    The oxidation of lithium, sodium, potassium, rubidium, cesium and sodium-potassium alloys by dry oxygen is studied at several temperatures and in the oxygen pressure range 40 to 400 mmHg. One distinguishes three different oxidation behaviours (inflammation, ignition and slow combustion) whose zones are precised in function of the temperature. The slow oxidation kinetic laws, the composition of oxides and the motive of oxides colorations are determined. At least, the experimental data are construed theoretically. (author) [French] L'oxydation du lithium, du sodium, du potassium, du rubidium, du cesium et des alliages sodium-potassium par l'oxygene sec est etudiee a diverses temperatures et a des pressions comprises entre 40 et 400 mmHg d'oxygene. On distingue trois processus d'oxydation differents (l'inflammation, l'ignition et la combustion lente) dont les domaines en fonction de la temperature sont precises. Les lois cinetiques d'oxydation lente, la nature des oxydes formes ainsi que les causes des colorations de ces oxydes sont determinees. Enfin les resultats obtenus sont interpretes theoriquement. (auteur)

  9. Effet du stress oxydant sur les cavéoles dans les cellules musculaires squelettiques

    OpenAIRE

    Mougeolle, Alexis

    2014-01-01

    La sarcopénie est une maladie dégénérative liée à l’âge qui se caractérise par une perte progressive et involontaire de la masse et de la force musculaire. Elle s’accompagne d’une atteinte de la régénération musculaire et d’une accumulation des espèces réactives de l’oxygène. Les cavéoles sont des invaginations de la membrane plasmique. Dans le muscle, elles jouent un rôle dans la différenciation des cellules satellites et dans le maintien de l’unité contractile dans le muscle différencié. Ce...

  10. Effects of constant voltage and constant current stress in PCBM:P3HT solar cells

    DEFF Research Database (Denmark)

    Cester, Andrea; Rizzo, Aldo; Bazzega, A.;

    2015-01-01

    The aimof this work is the investigation of forward and reverse bias stress effects, cell self-heating and annealing in roll coated organic solar cells with PCBM:P3HT active layer. In reverse bias stress cells show a constant degradation over time. In forward current stress cells alternate degrad...

  11. Accelerated stress testing of amorphous silicon solar cells

    Science.gov (United States)

    Stoddard, W. G.; Davis, C. W.; Lathrop, J. W.

    1985-01-01

    A technique for performing accelerated stress tests of large-area thin a-Si solar cells is presented. A computer-controlled short-interval test system employing low-cost ac-powered ELH illumination and a simulated a-Si reference cell (seven individually bandpass-filtered zero-biased crystalline PIN photodiodes) calibrated to the response of an a-Si control cell is described and illustrated with flow diagrams, drawings, and graphs. Preliminary results indicate that while most tests of a program developed for c-Si cells are applicable to a-Si cells, spurious degradation may appear in a-Si cells tested at temperatures above 130 C.

  12. Resistance of oxidative stress in biofilm and planktonic cells

    Directory of Open Access Journals (Sweden)

    Witold Jakubowski

    2015-04-01

    Full Text Available This work studied the susceptibility of biofilm produced by E. coli to oxidative stress, and compared the components of free radicals defences: level of glutathione, catalase and dismutase activities in planktonic and biofilm located cells. Results showed the diversity of responses to oxidative stress in bacterial cells in log or stationary phases in both planktonic and biofilm forms. The bacteria were exposed to free-radical donors (H2O2, tBOOH, menadione, SIN-1 or peroxynitrite in a wide range of final concentrations, from 0.5 to 10mM. Different level of toxicity of individual donors, independence of cell type (planktonic forms or biofilm and phases of growth were observed. The highest oxidative stress resistance was observed for the cells in logarithmic phase of growth treated with H2O2, both in planktonic and biofilm forms, whereas for the cells in stationary phase, the highest resistance was observed for menadione. These results showed higher efficiency of agents based on superoxide anion donors in combating bacteria colonizing abiotic surfaces stainless steel (AISI 316L.

  13. Nuclear lamins and oxidative stress in cell proliferation and longevity.

    Science.gov (United States)

    Shimi, Takeshi; Goldman, Robert D

    2014-01-01

    In mammalian cells, the nuclear lamina is composed of a complex fibrillar network associated with the inner membrane of the nuclear envelope. The lamina provides mechanical support for the nucleus and functions as the major determinant of its size and shape. At its innermost aspect it associates with peripheral components of chromatin and thereby contributes to the organization of interphase chromosomes. The A- and B-type lamins are the major structural components of the lamina, and numerous mutations in the A-type lamin gene have been shown to cause many types of human diseases collectively known as the laminopathies. These mutations have also been shown to cause a disruption in the normal interactions between the A and B lamin networks. The impact of these mutations on nuclear functions is related to the roles of lamins in regulating various essential processes including DNA synthesis and damage repair, transcription and the regulation of genes involved in the response to oxidative stress. The major cause of oxidative stress is the production of reactive oxygen species (ROS), which is critically important for cell proliferation and longevity. Moderate increases in ROS act to initiate signaling pathways involved in cell proliferation and differentiation, whereas excessive increases in ROS cause oxidative stress, which in turn induces cell death and/or senescence. In this review, we cover current findings about the role of lamins in regulating cell proliferation and longevity through oxidative stress responses and ROS signaling pathways. We also speculate on the involvement of lamins in tumor cell proliferation through the control of ROS metabolism.

  14. Mitofusin-2 protects against cold stress-induced cell injury in HEK293 cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenbin; Chen, Yaomin; Yang, Qun; Che, Honglei; Chen, Xiangjun; Yao, Ting; Zhao, Fang; Liu, Mingchao; Ke, Tao [Department of Occupational and Environmental Health, School of Public Health, Fourth Military Medical University, Xi' an 710032 (China); Chen, Jingyuan, E-mail: jy_chen@fmmu.edu.cn [Department of Occupational and Environmental Health, School of Public Health, Fourth Military Medical University, Xi' an 710032 (China); Luo, Wenjing, E-mail: luowenj@fmmu.edu.cn [Department of Occupational and Environmental Health, School of Public Health, Fourth Military Medical University, Xi' an 710032 (China)

    2010-06-25

    Mitochondrial impairment is hypothesized to contribute to cell injury during cold stress. Mitochondria fission and fusion are closely related in the function of the mitochondria, but the precise mechanisms whereby these processes regulate cell injury during cold stress remain to be determined. HEK293 cells were cultured in a cold environment (4.0 {+-} 0.1 {sup o}C) for 2, 4, 8, or 12 h. Western blot analyses showed that these cells expressed decreased fission-related protein Drp1 and increased fusion-related protein Mfn2 at 4 h; meanwhile, electron microscopy analysis revealed large and long mitochondrial morphology within these cells, indicating increased mitochondrial fusion. With silencing of Mfn2 but not of Mfn1 by siRNA promoted cold-stress-induced cell death with decreased ATP production in HEK293 cells. Our results show that increased expression of Mfn2 and mitochondrial fusion are important for mitochondrial function as well as cell survival during cold stress. These findings have important implications for understanding the mechanisms of mitochondrial fusion and fission in cold-stress-induced cell injury.

  15. Uranium induces oxidative stress in lung epithelial cells

    International Nuclear Information System (INIS)

    Uranium compounds are widely used in the nuclear fuel cycle, antitank weapons, tank armor, and also as a pigment to color ceramics and glass. Effective management of waste uranium compounds is necessary to prevent exposure to avoid adverse health effects on the population. Health risks associated with uranium exposure includes kidney disease and respiratory disorders. In addition, several published results have shown uranium or depleted uranium causes DNA damage, mutagenicity, cancer and neurological defects. In the current study, uranium toxicity was evaluated in rat lung epithelial cells. The study shows uranium induces significant oxidative stress in rat lung epithelial cells followed by concomitant decrease in the antioxidant potential of the cells. Treatment with uranium to rat lung epithelial cells also decreased cell proliferation after 72 h in culture. The decrease in cell proliferation was attributed to loss of total glutathione and superoxide dismutase in the presence of uranium. Thus the results indicate the ineffectiveness of antioxidant system's response to the oxidative stress induced by uranium in the cells. (orig.)

  16. Effect of Zinc and Nitric Oxide on Monocyte Adhesion to Endothelial Cells under Shear Stress

    OpenAIRE

    Lee, Sungmun; Eskin, Suzanne G.; Shah, Ankit K.; Schildmeyer, Lisa A.; McIntire, Larry V.

    2011-01-01

    This study describes the effect of zinc on monocyte adhesion to endothelial cells under different shear stress regimens, which may trigger atherogenesis. Human umbilical vein endothelial cells were exposed to steady shear stress (15 dynes/cm2 or 1 dyne/cm2) or reversing shear stress (time average 1 dyne/cm2) for 24 hours. In all shear stress regimes, zinc deficiency enhanced THP-1 cell adhesion, while heparinase III reduced monocyte adhesion following reversing shear stress exposure. Unlike o...

  17. Hybridoma cell behaviour in continuous culture under hyperosmotic stress.

    Science.gov (United States)

    Cherlet, M; Marc, A

    1999-01-01

    In this paper, we propose an alternative strategy to the ones proposed before (Oh et al., 1993; Øyaas et al., 1994a) to get real increases of global final antibody titer and production at hyperosmotic stress, by reducing the detrimental effect of such a stress on cell growth, and conserving the stimulating effect on antibody production. It consists of cultivating the cells in continuous culture and increasing the osmolality stepwise. In this way, the cells could progressively adapt to the higher osmolality at each step and antibody titers could be nearly doubled at 370 and 400 mOsm kg-1, compared to the standard osmolality of 335 mOsm kg-1. Surprisingly, the stimulation of antibody production was not confirmed for higher osmolalities, 425 and 450 mOsm kg- 1, despite the minor negative effect on cell growth. Intracellular IgG analysis by flow cytometry revealed at these osmolalities a significant population of non-producing cells. However, even when taking into account this non-producing population, a stimulating effect on antibody production could not be shown at these highest osmolalities. It seems to us that osmolality has a significant effect on the appearance of these non-producing cells, since they were not observed in continuous cultures at standard osmolality, of comparable duration and at an even higher dilution rate. The appearance of the non-producing cells coincides furthermore with modifications of the synthesised antibody, as shown by electrophoretic techniques. It is however not really clear if these two observations reflect actually the same phenomenon. Hyperosmolality affects the cell behaviour in continuous culture in multiple ways, independently of the growth rate, counting all at least partially for the observed stimulation of antibody production: acceleration of the amino acid, and in particular the glutamine metabolism, increase of the cell volume, increase of the intracellular pH and accumulation of cells in the G1 cell cycle phase. PMID

  18. Limiting replication stress during somatic cell reprogramming reduces genomic instability in induced pluripotent stem cells

    OpenAIRE

    Ruiz, Sergio; Lopez Contreras, Andres J.; Gabut, Mathieu; Marion, Rosa M.; Guti??rrez Mart??nez, Paula; Bua, Sabela; Ram??rez, Oscar; Olalde, I??igo; Rodrigo Perez, Sara; Li, Han; Marqu??s i Bonet, Tom??s, 1975-; Serrano, Manuel; Blasco, Maria A; Batada, Nizar N; Fern??ndez Capetillo, Oscar

    2015-01-01

    The generation of induced pluripotent stem cells (iPSC) from adult somatic cells is one of the most remarkable discoveries in recent decades. However, several works have reported evidence of genomic instability in iPSC, raising concerns on their biomedical use. The reasons behind the genomic instability observed in iPSC remain mostly unknown. Here we show that, similar to the phenomenon of oncogene-induced replication stress, the expression of reprogramming factors induces replication stress....

  19. Ignition et oxydation des particules de combustible solide pulvérisé Ignition and Oxidation of Pulverized Solid Fuel

    Directory of Open Access Journals (Sweden)

    De Soete G. G.

    2006-11-01

    Full Text Available On présente dans cet article, en utilisant la méthode du ruban chauffé, une étude de la compétition entre (1 la dévolatilisation et l'oxydation consécutive des produits de pyrolyse et (2 l'ignition de la matrice solide et sa combustion rapide. La comparaison entre le moment de l'ignition et le début de la pyrolyse permet de déterminer en fonction de la température, de la taille des particules et de la concentration en oxygène, le domaine dans lequel l'ignition d'un combustible solide pyrolysable est du type whole coal ignition (c'est-à-dire lorsque l'ignition intervient avant que la pyrolyse devienne mesurable. Les résultats suggèrent que ce type d'ignition doit s'effectuer en règle générale dans les conditions de mise en oeuvre des combustibles solides pulvérisés dans les flammes industrielles. Dans le cas de l'ignition whole coal , la vitesse de combustion de la matrice solide est inhibée dans la période qui suit l'ignition. Cette inhibition est due d'une part à la difficulté pour l'oxygène de diffuser dans les pores pendant la sortie des produits de pyrolyse, et d'autre part à la consommation préférentielle de l'oxygène dans l'oxydation des produits de pyrolyse, principalement dans le cas où cette oxydation se développe sous forme de flamme. Ce n'est que lorsque la pyrolyse s'achève que la vitesse de combustion hétérogène peut atteindre sa valeur stationnaire normale, qui est alors pratiquement identique à celle du coke. Aux températures situées entre la température d'ignition du combustible solide et la température d'extinction du coke résiduel, la combustion est incomplète, une extinction intervenant à un degré de dévolatilisation d'autant plus grande que la température est élevée. Ce phénomène s'explique qualitativement par la théorie classique d'ignition thermique lorsqu'on l'applique au cas particulier des combustibles solides pyrolysables. Les températures d'ignition ainsi que les d

  20. Cell stiffness, contractile stress and the role of extracellular matrix

    Science.gov (United States)

    An, Steven S.; Kim, Jina; Ahn, Kwangmi; Trepat, Xavier; Drake, Kenneth J.; Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne; Fredberg, Jeffrey J.; Biswal, Shyam

    2010-01-01

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses. PMID:19327344

  1. Cell stiffness, contractile stress and the role of extracellular matrix

    Energy Technology Data Exchange (ETDEWEB)

    An, Steven S., E-mail: san@jhsph.edu [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Kim, Jina [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Ahn, Kwangmi [Division of Biostatistics, Penn State College of Medicine, Hershey, PA 17033 (United States); Trepat, Xavier [CIBER, Enfermedades Respiratorias, 07110 Bunyola (Spain); Drake, Kenneth J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Kumar, Sarvesh; Ling, Guoyu; Purington, Carolyn; Rangasamy, Tirumalai; Kensler, Thomas W.; Mitzner, Wayne [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Fredberg, Jeffrey J. [Division of Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115 (United States); Biswal, Shyam [Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Room E-7616, Baltimore, MD 21205 (United States); Division of Pulmonary and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD 21205 (United States)

    2009-05-15

    Here we have assessed the effects of extracellular matrix (ECM) composition and rigidity on mechanical properties of the human airway smooth muscle (ASM) cell. Cell stiffness and contractile stress showed appreciable changes from the most relaxed state to the most contracted state: we refer to the maximal range of these changes as the cell contractile scope. The contractile scope was least when the cell was adherent upon collagen V, followed by collagen IV, laminin, and collagen I, and greatest for fibronectin. Regardless of ECM composition, upon adherence to increasingly rigid substrates, the ASM cell positively regulated expression of antioxidant genes in the glutathione pathway and heme oxygenase, and disruption of a redox-sensitive transcription factor, nuclear erythroid 2 p45-related factor (Nrf2), culminated in greater contractile scope. These findings provide biophysical evidence that ECM differentially modulates muscle contractility and, for the first time, demonstrate a link between muscle contractility and Nrf2-directed responses.

  2. Oxidative stress in retinal pigment epithelium cells increases exosome secretion and promotes angiogenesis in endothelial cells.

    Science.gov (United States)

    Atienzar-Aroca, Sandra; Flores-Bellver, Miguel; Serrano-Heras, Gemma; Martinez-Gil, Natalia; Barcia, Jorge M; Aparicio, Silvia; Perez-Cremades, Daniel; Garcia-Verdugo, Jose M; Diaz-Llopis, Manuel; Romero, Francisco J; Sancho-Pelluz, Javier

    2016-08-01

    The retinal pigment epithelium (RPE), a monolayer located between the photoreceptors and the choroid, is constantly damaged by oxidative stress, particularly because of reactive oxygen species (ROS). As the RPE, because of its physiological functions, is essential for the survival of the retina, any sustained damage may consequently lead to loss of vision. Exosomes are small membranous vesicles released into the extracellular medium by numerous cell types, including RPE cells. Their cargo includes genetic material and proteins, making these vesicles essential for cell-to-cell communication. Exosomes may fuse with neighbouring cells influencing their fate. It has been observed that RPE cells release higher amounts of exosomes when they are under oxidative stress. Exosomes derived from cultured RPE cells were isolated by ultracentrifugation and quantified by flow cytometry. VEGF receptors (VEGFR) were analysed by both flow cytometry and Western blot. RT-PCR and qPCR were conducted to assess mRNA content of VEGFRs in exosomes. Neovascularization assays were performed after applying RPE exosomes into endothelial cell cultures. Our results showed that stressed RPE cells released a higher amount of exosomes than controls, with a higher expression of VEGFR in the membrane, and enclosed an extra cargo of VEGFR mRNA. Angiogenesis assays confirmed that endothelial cells increased their tube formation capacity when exposed to stressed RPE exosomes. PMID:26999719

  3. Oriented cell division affects the global stress and cell packing geometry of a monolayer under stretch.

    Science.gov (United States)

    Xu, Guang-Kui; Liu, Yang; Zheng, Zhaoliang

    2016-02-01

    Cell division plays a vital role in tissue morphogenesis and homeostasis, and the division plane is crucial for cell fate. For isolated cells, extensive studies show that the orientation of divisions is sensitive to cell shape and the direction of extrinsic mechanical forces. However, it is poorly understood that how the cell divides within a cell monolayer and how the local stress change, due to the division, affects the global stress of epithelial monolayers. Here, we use the vertex dynamics models to investigate the effects of division orientation on the configurations and mechanics of a cell monolayer under stretch. We examine three scenarios of the divisions: dividing along the stretch axis, dividing along the geometric long axis of cells, and dividing at a random angle. It is found that the division along the long cell axis can induce the minimal energy difference, and the global stress of the monolayer after stretch releases more rapidly in this case. Moreover, the long-axis division can result in more random cell orientations and more isotropic cell shapes within the monolayer, comparing with other two cases. This study helps understand the division orientation of cells within a monolayer under mechanical stimuli, and may shed light on linking individual cell's behaviors to the global mechanics and patterns of tissues.

  4. Endoplasmic Reticulum Stress Links Oxidative Stress to Impaired Pancreatic Beta-Cell Function Caused by Human Oxidized LDL

    Science.gov (United States)

    Favre, Dimitri; Ezanno, Hélène; Bonnefond, Amélie; Bonner, Caroline; Gmyr, Valéry; Kerr-Conte, Julie; Gauthier, Benoit R.; Widmann, Christian; Waeber, Gérard; Pattou, François; Froguel, Philippe; Abderrahmani, Amar

    2016-01-01

    Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment. PMID:27636901

  5. Endoplasmic Reticulum Stress Links Oxidative Stress to Impaired Pancreatic Beta-Cell Function Caused by Human Oxidized LDL.

    Science.gov (United States)

    Plaisance, Valérie; Brajkovic, Saška; Tenenbaum, Mathie; Favre, Dimitri; Ezanno, Hélène; Bonnefond, Amélie; Bonner, Caroline; Gmyr, Valéry; Kerr-Conte, Julie; Gauthier, Benoit R; Widmann, Christian; Waeber, Gérard; Pattou, François; Froguel, Philippe; Abderrahmani, Amar

    2016-01-01

    Elevated plasma concentration of the pro-atherogenic oxidized low density lipoprotein cholesterol (LDL) triggers adverse effects in pancreatic beta-cells and is associated with type 2 diabetes. Here, we investigated whether the endoplasmic reticulum (ER) stress is a key player coupling oxidative stress to beta-cell dysfunction and death elicited by human oxidized LDL. We found that human oxidized LDL activates ER stress as evidenced by the activation of the inositol requiring 1α, and the elevated expression of both DDIT3 (also called CHOP) and DNAJC3 (also called P58IPK) ER stress markers in isolated human islets and the mouse insulin secreting MIN6 cells. Silencing of Chop and inhibition of ER stress markers by the chemical chaperone phenyl butyric acid (PBA) prevented cell death caused by oxidized LDL. Finally, we found that oxidative stress accounts for activation of ER stress markers induced by oxidized LDL. Induction of Chop/CHOP and p58IPK/P58IPK by oxidized LDL was mimicked by hydrogen peroxide and was blocked by co-treatment with the N-acetylcystein antioxidant. As a conclusion, the harmful effects of oxidized LDL in beta-cells requires ER stress activation in a manner that involves oxidative stress. This mechanism may account for impaired beta-cell function in diabetes and can be reversed by antioxidant treatment. PMID:27636901

  6. Oxidative stress and cell adhesion in skin cancer

    OpenAIRE

    Hintsala, H.-R. (Hanna-Riikka)

    2016-01-01

    Abstract Skin is the largest organ in our body protecting us from ultraviolet radiation and xenobiotics. UV-radiation is a common cause of squamocellular carcinoma and melanoma of the skin that cause morbidity and mortality world wide. Reactive oxygen species are constantly formed by, for example, cellular respiration and UV-radiation, and they can readily react with virtually any macromolecule within cell structures causing damage to DNA, proteins and lipids. Oxidative stress (OS) is a h...

  7. From Global Stresses to Local Cell Packing During Development

    Science.gov (United States)

    Lubensky, David

    2011-03-01

    To perform their functions, cells in epithelial tissues must often adopt highly regular packings. It is still not fully understood how these ordered arrangements of cells arise from disordered, proliferative epithelia during development. I will use experimental and theoretical studies on an attractive model system, the cone cell mosaic in fish retina, to illustrate some ways that mechanical forces and cell signaling can interact to produce this transformation. Experiments examining the response to surgical lesions suggest that the correct mechanical environment at the tissue scale is essential to induce cone cells to rearrange into a rectangular lattice. Starting from this observation, I will argue that large-scale mechanical stresses naturally couple to and orient cell polarization and that this coupling can lead cells to line up in regular rows, as observed in the fish retina. This model predicts that cells in the rows will adopt characteristic trapezoidal shapes and that fragments of rows will persist even in tissue where the mosaic pattern is disrupted by lesions; these predictions are borne out by an analysis of cell packings at the level of the zonula occludens in wildtype and lesioned retinas. Supported by NSF grant IOS-0952873.

  8. Cell cycle controls stress response and longevity in C. elegans

    Science.gov (United States)

    Dottermusch, Matthias; Lakner, Theresa; Peyman, Tobias; Klein, Marinella; Walz, Gerd; Neumann-Haefelin, Elke

    2016-01-01

    Recent studies have revealed a variety of genes and mechanisms that influence the rate of aging progression. In this study, we identified cell cycle factors as potent regulators of health and longevity in C. elegans. Focusing on the cyclin-dependent kinase 2 (cdk-2) and cyclin E (cye-1), we show that inhibition of cell cycle genes leads to tolerance towards environmental stress and longevity. The reproductive system is known as a key regulator of longevity in C. elegans. We uncovered the gonad as the central organ mediating the effects of cell cycle inhibition on lifespan. In particular, the proliferating germ cells were essential for conferring longevity. Steroid hormone signaling and the FOXO transcription factor DAF-16 were required for longevity associated with cell cycle inhibition. Furthermore, we discovered that SKN-1 (ortholog of mammalian Nrf proteins) activates protective gene expression and induces longevity when cell cycle genes are inactivated. We conclude that both, germline absence and inhibition through impairment of cell cycle machinery results in longevity through similar pathways. In addition, our studies suggest further roles of cell cycle genes beyond cell cycle progression and support the recently described connection of SKN-1/Nrf to signals deriving from the germline. PMID:27668945

  9. Stress analysis for wall structure in mobile hot cell design

    Energy Technology Data Exchange (ETDEWEB)

    Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  10. Effect of microculture on cell metabolism and biochemistry: do cells get stressed in microchannels?

    Science.gov (United States)

    Su, Xiaojing; Theberge, Ashleigh B; January, Craig T; Beebe, David J

    2013-02-01

    Microfluidics is emerging as a promising platform for cell culture, enabling increased microenvironment control and potential for integrated analysis compared to conventional macroculture systems such as well plates and Petri dishes. To advance the use of microfluidic devices for cell culture, it is necessary to better understand how miniaturization affects cell behavior. In particular, microfluidic devices have significantly higher surface-area-to-volume ratios than conventional platforms, resulting in lower volumes of media per cell, which can lead to cell stress. We investigated cell stress under a variety of culture conditions using three cell lines: parental HEK (human embryonic kidney) cells and transfected HEK cells that stably express wild-type (WT) and mutant (G601S) human ether-a-go-go related gene (hERG) potassium channel protein. These three cell lines provide a unique model system through which to study cell-type-specific responses in microculture because mutant hERG is known to be sensitive to environmental conditions, making its expression a particularly sensitive readout through which to compare macro- and microculture. While expression of WT-hERG was similar in microchannel and well culture, the expression of mutant G601S-hERG was reduced in microchannels. Expression of the endoplasmic reticulum (ER) stress marker immunoglobulin binding protein (BiP) was upregulated in all three cell lines in microculture. Using BiP expression, glucose consumption, and lactate accumulation as readouts we developed methods for reducing ER stress including properly increasing the frequency of media replacement, reducing cell seeding density, and adjusting the serum concentration and buffering capacity of culture medium. Indeed, increasing the buffering capacity of culture medium or frequency of media replacement partially restored the expression of the G601S-hERG in microculture. This work illuminates how biochemical properties of cells differ in macro- and

  11. Etude paramétrique des effets de la stratification de la flamme sur les émissions d'oxydes d'azote (première partie Parametric Study of Statification Effects on Nitric Oxyde Emissions from Flam (Part One

    Directory of Open Access Journals (Sweden)

    De Soete G.

    2006-11-01

    Full Text Available On a étudié les effets de la stratification de flammes de prémélange laminaires, stationnaires et non stationnaires, sur les émissions d'oxydes d'azote formés par le mécanisme thermique et par le mécanisme du fuel-NO. Deux modalités de stratification ont été considérées, l'une juxtaposant sur le même plan les zones de combustion primaires correspond aux fractions individuelles du mélange stratifié (stratification en juxtaposition, l'autre disposant ces zones de combustion primaires sur des plans successifs (stratification en succession. Les émissions d'oxydes d'azote mesurées sur les flammes stratifiées ont été comparées à celles provenant de flammes non stratifiées de même composition globale et brûlant dans des conditions identiques. L'étude montre qu'il y a lieu de distinguer deux types d'effets de stratification. II existe un effet primaire -qui est la simple conséquence du morcellement de la flamme en un certain nombre de zones de combustion primaires (caractérisées par des compositions différentes et qui se traduit par l'additivité des émissions individuelles provenant des fractions respectives du mélange. L'effet total de la stratification se réduit à ce seul effet primaire au cas où les vitesses de formation des oxydes d'azote deviennent nulles après re-mélange des produits de combustion provenant des différentes fractions du mélange stratifié. Il en est ainsi par exemple dans le cas des flammes non stationnaires stratifiées en succession ; il en résulte alors soit une augmentation soit une diminution des émissions d'oxydes d'azote par rapport à celles des flammes non stratifiées, suivant la valeur de la richesse globale et du degré de stratification. Des effets secondaires de stratification se manifestent chaque fois que des produits de combustion, provenant d'une zone de combustion primaire donnée, sont introduits totalement ou partiellement dans un autre front de flamme créé par la

  12. Collective cancer cell invasion induced by coordinated contractile stresses.

    Science.gov (United States)

    Jimenez Valencia, Angela M; Wu, Pei-Hsun; Yogurtcu, Osman N; Rao, Pranay; DiGiacomo, Josh; Godet, Inês; He, Lijuan; Lee, Meng-Horng; Gilkes, Daniele; Sun, Sean X; Wirtz, Denis

    2015-12-22

    The physical underpinnings of fibrosarcoma cell dissemination from a tumor in a surrounding collagen-rich matrix are poorly understood. Here we show that a tumor spheroid embedded in a 3D collagen matrix exerts large contractile forces on the matrix before invasion. Cell invasion is accompanied by complex spatially and temporally dependent patterns of cell migration within and at the surface of the spheroids that are fundamentally different from migratory patterns of individual fibrosarcoma cells homogeneously distributed in the same type of matrix. Cells display a continuous transition from a round morphology at the spheroid core, to highly aligned elongated morphology at the spheroid periphery, which depends on both β1-integrin-based cell-matrix adhesion and myosin II/ROCK-based cell contractility. This isotropic-to-anisotropic transition corresponds to a shift in migration, from a slow and unpolarized movement at the core, to a fast, polarized and persistent one at the periphery. Our results also show that the ensuing collective invasion of fibrosarcoma cells is induced by anisotropic contractile stresses exerted on the surrounding matrix.

  13. Plasmodesmal-mediated cell-to-cell transport in wheat roots is modulated by anaerobic stress

    Science.gov (United States)

    Cleland, R. E.; Fujiwara, T.; Lucas, W. J.

    1994-01-01

    Cell-to-cell transport of small molecules and ions occurs in plants through plasmodesmata. Plant roots are frequently subjected to localized anaerobic stress, with a resultant decrease in ATP. In order to determine the effect of this stress on plasmodesmal transport, fluorescent dyes of increasing molecular weight (0.46 to 1OkDa) were injected into epidermal and cortical cells of 3-day-old wheat roots, and their movement into neighboring cells was determined by fluorescence microscopy. Anaerobiosis was generated by N2 gas or simulated by the presence of sodium azide, both of which reduced the ATP levels in the tissue by over 80%. In the absence of such stress, the upper limit for movement, or size exclusion limit (SEL), of cortical plasmodesmata was roots, indicating that plasmodesmata may be conduits for nucleotide (ATP and ADP) exchange between cells. Upon imposition of stress, the SEL rose to between 5 and 10 kDa. This response of plasmodesmata to a decrease in the level of ATP suggests that they are constricted by an ATP-dependent process so as to maintain a restricted SEL. When roots are subjected to anaerobic stress, an increase in SEL may permit enhanced delivery of sugars to the affected cells of the root where anaerobic respiration could regenerate the needed ATP.

  14. Furan fatty acids efficiently rescue brain cells from cell death induced by oxidative stress

    NARCIS (Netherlands)

    Teixeira, A.; Cox, R.C.; Egmond, M.R.

    2013-01-01

    Treatment of rat brain C6 astroglioma cells with furan fatty acid F6 prior to exposure to hydrogen peroxide shows a strong protective effect of F6 against cell death resulting from oxidative stress. This protective effect is obtained only for F6 administered as a free fatty acid and with an intact f

  15. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  16. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia.

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  17. Prodigiosin activates endoplasmic reticulum stress cell death pathway in human breast carcinoma cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Mu-Yun [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Shen, Yuh-Chiang [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); National Research Institute of Chinese Medicine, Taipei, Taiwan (China); Lu, Chien-Hsing [Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Obstetrics and Gynecology, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yang, Shu-Yi [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Ho, Tsing-Fen [Department of Medical Laboratory Science and Biotechnology, Central Taiwan University of Science and Technology, Taichung, Taiwan (China); Peng, Yu-Ta [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Chang, Chia-Che, E-mail: chia_che@dragon.nchu.edu.tw [Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan (China); Agricultural Biotechnology Center, National Chung Hsing University, Taichung, Taiwan (China); Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China)

    2012-12-15

    Prodigiosin is a bacterial tripyrrole pigment with potent cytotoxicity against diverse human cancer cell lines. Endoplasmic reticulum (ER) stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable. In this study, the role of ER stress in prodigiosin-induced cytotoxicity was elucidated for the first time. Comparable to the ER stress inducer thapsigargin, prodigiosin up-regulated signature ER stress markers GRP78 and CHOP in addition to activating the IRE1, PERK and ATF6 branches of the unfolded protein response (UPR) in multiple human breast carcinoma cell lines, confirming prodigiosin as an ER stress inducer. Prodigiosin transcriptionally up-regulated CHOP, as evidenced by its promoting effect on the CHOP promoter activity. Of note, knockdown of CHOP effectively lowered prodigiosin's capacity to evoke PARP cleavage, reduce cell viability and suppress colony formation, highlighting an essential role of CHOP in prodigiosin-induced cytotoxic ER stress response. In addition, prodigiosin down-regulated BCL2 in a CHOP-dependent manner. Importantly, restoration of BCL2 expression blocked prodigiosin-induced PARP cleavage and greatly enhanced the survival of prodigiosin-treated cells, suggesting that CHOP-dependent BCL2 suppression mediates prodigiosin-elicited cell death. Moreover, pharmacological inhibition of JNK by SP600125 or dominant-negative blockade of PERK-mediated eIF2α phosphorylation impaired prodigiosin-induced CHOP up-regulation and PARP cleavage. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Mechanistically, prodigiosin engages the IRE1–JNK and PERK–eIF2α branches of the UPR signaling to up-regulate CHOP, which in turn mediates BCL2 suppression to induce cell death. Highlights: ► Prodigiosin is a bacterial tripyrrole pigment with potent anticancer effect. ► Prodigiosin is herein identified

  18. Cocaine-induced oxidative stress precedes cell death in human neuronal progenitor cells.

    Science.gov (United States)

    Poon, H Fai; Abdullah, Laila; Mullan, Myles A; Mullan, Michael J; Crawford, Fiona C

    2007-01-01

    By 2003, an estimated 34 million Americans had used cocaine according to the National Survey on Drug Use & Health. About 5.9 million of those had used in the past 12 months. Chronic cocaine users often develop addiction, dependency and tolerance to the drug. The psychological and physical effects of cocaine are due to the disruption of the limbic system in the central nervous system (CNS). Increased oxidative stress reported in the frontal cortex and the striatum of rats exposed to cocaine suggests that oxidative damage plays a significant role in cocaine-induced disruption of the CNS. Although it is evident that cocaine induces oxidative stress in the CNS, little has been learned about whether such increased oxidative stress is also relevant to apoptosis in cocaine-exposed models. To gain insight into the role of cocaine-induced oxidative stress in apoptosis, we hypothesized that oxidative stress precedes cell death when cocaine is administrated. To test this hypothesis, we have monitored the oxidative stress and apoptotic effects of acute cocaine exposure in human neuronal progenitor cells (HNPC). We found that oxidative stress was significantly increased at 48h after a 30min cocaine exposure compared to control cells, and that this was followed by cell death at 72h. Using the same experimental paradigm we have previously shown that pro-inflammatory genes are up-regulated in cocaine-exposed HNPC at 24h. Therefore, we suggest that the increased oxidative stress (possibly mediated by inflammatory responses) precedes cell death in cocaine-exposed HNPC. This may have implications for the consequences of cocaine abuse in situations where antioxidant capacity is compromised, as in the aging brain. PMID:16956698

  19. Metabolic Adaptations of Azospirillum brasilense to Oxygen Stress by Cell-to-Cell Clumping and Flocculation

    Science.gov (United States)

    Bible, Amber N.; Khalsa-Moyers, Gurusahai K.; Mukherjee, Tanmoy; Green, Calvin S.; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Hurst, Gregory B.

    2015-01-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists. PMID:26407887

  20. Low zinc environment induces stress signaling, senescence and mixed cell death modalities in colon cancer cells.

    Science.gov (United States)

    Rudolf, Emil; Rudolf, Kamil

    2015-12-01

    Currently it is not clear what type of the final cellular response (i.e. cell death modality or senescence) is induced upon chronic intracellular zinc depletion in colon cancer cells. To address this question, isogenic colon cancer lines SW480 and SW620 exposed to low zinc environment were studied over the period of 6 weeks. Low zinc environment reduced total as well as free intracellular zinc content in both cell lines. Decreased intracellular zinc content resulted in changes in cellular proliferation, cell cycle distribution and activation of stress signaling. In addition, colonocytes with low zinc content displayed increased levels of oxidative stress, changes in mitochondrial activity but in the absence of significant DNA damage. Towards the end of treatment (4th-6th week), exposed cells started to change morphologically, and typical markers of senescence as well as cell death appeared. Of two examined colon cancer cell lines, SW480 cells proved to activate predominantly senescent phenotype, with frequent form of demise being necrosis and mixed cell death modality but not apoptosis. Conversely, SW620 cells activated mostly cell death, with relatively equal distribution of apoptosis and mixed types, while senescent phenotypes and necrosis were present only in a small fraction of cell populations. Addition of zinc at the beginning of 4th week of treatment significantly suppressed cell death phenotypes in both cell lines but had no significant effect on senescence. In conclusion, presented results demonstrate variability of responses to chronic zinc depletion in colon cancer as modeled in vitro.

  1. Metabolic adaptations of Azospirillum brasilense to oxygen stress by cell-to-cell clumping and flocculation.

    Science.gov (United States)

    Bible, Amber N; Khalsa-Moyers, Gurusahai K; Mukherjee, Tanmoy; Green, Calvin S; Mishra, Priyanka; Purcell, Alicia; Aksenova, Anastasia; Hurst, Gregory B; Alexandre, Gladys

    2015-12-01

    The ability of bacteria to monitor their metabolism and adjust their behavior accordingly is critical to maintain competitiveness in the environment. The motile microaerophilic bacterium Azospirillum brasilense navigates oxygen gradients by aerotaxis in order to locate low oxygen concentrations that can support metabolism. When cells are exposed to elevated levels of oxygen in their surroundings, motile A. brasilense cells implement an alternative response to aerotaxis and form transient clumps by cell-to-cell interactions. Clumping was suggested to represent a behavior protecting motile cells from transiently elevated levels of aeration. Using the proteomics of wild-type and mutant strains affected in the extent of their clumping abilities, we show that cell-to-cell clumping represents a metabolic scavenging strategy that likely prepares the cells for further metabolic stresses. Analysis of mutants affected in carbon or nitrogen metabolism confirmed this assumption. The metabolic changes experienced as clumping progresses prime cells for flocculation, a morphological and metabolic shift of cells triggered under elevated-aeration conditions and nitrogen limitation. The analysis of various mutants during clumping and flocculation characterized an ordered set of changes in cell envelope properties accompanying the metabolic changes. These data also identify clumping and early flocculation to be behaviors compatible with the expression of nitrogen fixation genes, despite the elevated-aeration conditions. Cell-to-cell clumping may thus license diazotrophy to microaerophilic A. brasilense cells under elevated oxygen conditions and prime them for long-term survival via flocculation if metabolic stress persists.

  2. Residual stresses in a co-sintered SOC half-cell during post-sintering cooling

    DEFF Research Database (Denmark)

    Charlas, Benoit; Chatzichristodoulou, Christodoulos; Brodersen, Karen;

    2014-01-01

    Due to the thermal expansion mismatch between the layers of a Solid Oxide Cell, residual stresses (thermal stresses) develop during the cooling after sintering. Residual stresses can induce cell curvature for asymmetric cells but more importantly they also result in more fragile cells. Depending...... on the loading conditions, the additional stress needed to break the cells can indeed be smaller due to the initial thermo-mechanical stress state. The residual stresses can for a bilayer cell be approximated by estimating the temperature at which elastic stresses start to build up during the cooling, i.......e. the reference temperature (Tref) or the strain difference based on the curvature. This approximation gives good results for bilayers with a defined cooling temperature profile, where the curvature of the bilayer defines a unique balance between the two unknown residual stress states in the two layers...

  3. Material properties of the cell dictate stress-induced spreading and differentiation in embryonic stem cells

    Science.gov (United States)

    Chowdhury, Farhan; Na, Sungsoo; Li, Dong; Poh, Yeh-Chuin; Tanaka, Tetsuya S.; Wang, Fei; Wang, Ning

    2010-01-01

    Growing evidence suggests that physical microenvironments and mechanical stresses, in addition to soluble factors, help direct mesenchymal-stem-cell fate. However, biological responses to a local force in embryonic stem cells remain elusive. Here we show that a local cyclic stress through focal adhesions induced spreading in mouse embryonic stem cells but not in mouse embryonic stem-cell-differentiated cells, which were ten times stiffer. This response was dictated by the cell material property (cell softness), suggesting that a threshold cell deformation is the key setpoint for triggering spreading responses. Traction quantification and pharmacological or shRNA intervention revealed that myosin II contractility, F-actin, Src or cdc42 were essential in the spreading response. The applied stress led to oct3/4 gene downregulation in mES cells. Our findings demonstrate that cell softness dictates cellular sensitivity to force, suggesting that local small forces might have far more important roles in early development of soft embryos than previously appreciated.

  4. High glucose-mediated oxidative stress impairs cell migration.

    Directory of Open Access Journals (Sweden)

    Marcelo L Lamers

    Full Text Available Deficient wound healing in diabetic patients is very frequent, but the cellular and molecular causes are poorly defined. In this study, we evaluate the hypothesis that high glucose concentrations inhibit cell migration. Using CHO.K1 cells, NIH-3T3 fibroblasts, mouse embryonic fibroblasts and primary skin fibroblasts from control and diabetic rats cultured in 5 mM D-glucose (low glucose, LG, 25 mM D-glucose (high glucose, HG or 25 mM L-glucose medium (osmotic control--OC, we analyzed the migration speed, protrusion stability, cell polarity, adhesion maturation and the activity of the small Rho GTPase Rac1. We also analyzed the effects of reactive oxygen species by incubating cells with the antioxidant N-Acetyl-Cysteine (NAC. We observed that HG conditions inhibited cell migration when compared to LG or OC. This inhibition resulted from impaired cell polarity, protrusion destabilization and inhibition of adhesion maturation. Conversely, Rac1 activity, which promotes protrusion and blocks adhesion maturation, was increased in HG conditions, thus providing a mechanistic basis for the HG phenotype. Most of the HG effects were partially or completely rescued by treatment with NAC. These findings demonstrate that HG impairs cell migration due to an increase in oxidative stress that causes polarity loss, deficient adhesion and protrusion. These alterations arise, in large part, from increased Rac1 activity and may contribute to the poor wound healing observed in diabetic patients.

  5. Direct measurement of cell wall stress-stiffening and turgor pressure in live bacterial cells

    CERN Document Server

    Deng, Yi; Shaevitz, Joshua W

    2011-01-01

    The mechanical properties of gram-negative bacteria are governed by a rigid peptidoglycan (PG) cell wall and the turgor pressure generated by the large concentration of solutes in the cytoplasm. The elasticity of the PG has been measured in bulk and in isolated sacculi and shown to be compliant compared to the overall stiffness of the cell itself. However, the stiffness of the cell wall in live cells has not been measured. In particular, the effects that pressure-induced stress might have on the stiffness of the mesh-like PG network have not been addressed even though polymeric materials often exhibit large amounts of stress-stiffening. We study bulging Escherichia coli cells using atomic force microscopy to separate the contributions of the cell wall and turgor pressure to the overall cell stiffness. We find strong evidence of power-law stress-stiffening in the E. coli cell wall, with an exponent of $1.07 \\pm 0.25$, such that the wall is significantly stiffer in live cells ($E\\sim32\\pm10$ MPa) than in unpres...

  6. Inhibition of telomerase causes vulnerability to endoplasmic reticulum stress-induced neuronal cell death.

    Science.gov (United States)

    Hosoi, Toru; Nakatsu, Kanako; Shimamoto, Akira; Tahara, Hidetoshi; Ozawa, Koichiro

    2016-08-26

    Endoplasmic reticulum (ER) stress is implicated in several diseases, such as cancer and neurodegenerative diseases. In the present study, we investigated the possible involvement of telomerase in ER stress-induced cell death. ER stress-induced cell death was ameliorated in telomerase reverse transcriptase (TERT) over-expressing MCF7 cells (MCF7-TERT cell). Telomerase specific inhibitor, BIBR1532, reversed the inhibitory effect of TERT on ER stress-induced cell death in MCF7-TERT cells. These findings suggest that BIBR1532 may specifically inhibit telomerase activity, thereby inducing cell death in ER stress-exposed cells. TERT was expressed in the SH-SY5Y neuroblastoma cell line. To analyze the possible involvement of telomerase in ER stress-induced neuronal cell death, we treated SH-SY5Y neuroblastoma cells with BIBR1532 and analyzed ER stress-induced cell death. We found that BIBR1532 significantly enhanced the ER stress-induced neuronal cell death. These findings suggest that inhibition of telomerase activity may enhance vulnerability to neuronal cell death caused by ER stress. PMID:27443785

  7. Sea urchin immune cells as sentinels of environmental stress.

    Science.gov (United States)

    Pinsino, Annalisa; Matranga, Valeria

    2015-03-01

    Echinoderms, an ancient and very successful phylum of marine invertebrates, play a central role in the maintenance of ecosystem integrity and are constantly exposed to environmental pressure, including: predation, changes in temperature and pH, hypoxia, pathogens, UV radiation, metals, toxicants, and emerging pollutants like nanomaterials. The annotation of the sea urchin genome, so closely related to humans and other vertebrate genomes, revealed an unusually complex immune system, which may be the basis for why sea urchins can adapt to different marine environments and survive even in hazardous conditions. In this review, we give a brief overview of the morphological features and recognized functions of echinoderm immune cells with a focus on studies correlating stress and immunity in the sea urchin. Immune cells from adult Paracentrotus lividus, which have been introduced in the last fifteen years as sentinels of environmental stress, are valid tools to uncover basic molecular and regulatory mechanisms of immune responses, supporting their use in immunological research. Here we summarize laboratory and field studies that reveal the amenability of sea urchin immune cells for toxicological testing. PMID:25463510

  8. UVC-induced stress granules in mammalian cells.

    Directory of Open Access Journals (Sweden)

    Mohamed Taha Moutaoufik

    Full Text Available Stress granules (SGs are well characterized cytoplasmic RNA bodies that form under various stress conditions. We have observed that exposure of mammalian cells in culture to low doses of UVC induces the formation of discrete cytoplasmic RNA granules that were detected by immunofluorescence staining using antibodies to RNA-binding proteins. UVC-induced cytoplasmic granules are not Processing Bodies (P-bodies and are bone fide SGs as they contain TIA-1, TIA-1/R, Caprin1, FMRP, G3BP1, PABP1, well known markers, and mRNA. Concomitant with the accumulation of the granules in the cytoplasm, cells enter a quiescent state, as they are arrested in G1 phase of the cell cycle in order to repair DNA damages induced by UVC irradiation. This blockage persists as long as the granules are present. A tight correlation between their decay and re-entry into S-phase was observed. However the kinetics of their formation, their low number per cell, their absence of fusion into larger granules, their persistence over 48 hours and their slow decay, all differ from classical SGs induced by arsenite or heat treatment. The induction of these SGs does not correlate with major translation inhibition nor with phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α. We propose that a restricted subset of mRNAs coding for proteins implicated in cell cycling are removed from the translational apparatus and are sequestered in a repressed form in SGs.

  9. Protection by 6-aminonicotinamide against oxidative stress in cardiac cells

    DEFF Research Database (Denmark)

    Hofgaard, Johannes P; Sigurdardottir, Kristin Sigridur; Treiman, Marek

    2006-01-01

    necrosis following global ischemia in an isolated rat heart, apparently by limiting the oxidative injury component. We therefore explored the antioxidative potential of 6AN in a model using H9C2(2-1) rat cardiac myoblasts exposed to H2O2 stress. Dependent on the specific protocol, 6AN pretreatment for 6....... The protective effect of 6AN was associated with a decrease in total cell content of the reduced glutathione (GSH) by 15-44%, indicative of an oxidative shift in the GSH/GSSG system redox potential. We propose that this redox shift caused an increased Ca2+ leak through ryanodine receptors, reflecting their known...

  10. Oxidative Stress, Cell Death, and Other Damage to Alveolar Epithelial Cells Induced by Cigarette Smoke

    Directory of Open Access Journals (Sweden)

    Nagai A

    2003-09-01

    Full Text Available Abstract Cigarette smoking is a major risk factor in the development of various lung diseases, including pulmonary emphysema, pulmonary fibrosis, and lung cancer. The mechanisms of these diseases include alterations in alveolar epithelial cells, which are essential in the maintenance of normal alveolar architecture and function. Following cigarette smoking, alterations in alveolar epithelial cells induce an increase in epithelial permeability, a decrease in surfactant production, the inappropriate production of inflammatory cytokines and growth factors, and an increased risk of lung cancer. However, the most deleterious effect of cigarette smoke on alveolar epithelial cells is cell death, i.e., either apoptosis or necrosis depending on the magnitude of cigarette smoke exposure. Cell death induced by cigarette smoke exposure can largely be accounted for by an enhancement in oxidative stress. In fact, cigarette smoke contains and generates many reactive oxygen species that damage alveolar epithelial cells. Whether apoptosis and/or necrosis in alveolar epithelial cells is enhanced in healthy cigarette smokers is presently unclear. However, recent evidence indicates that the apoptosis of alveolar epithelial cells and alveolar endothelial cells is involved in the pathogenesis of pulmonary emphysema, an important cigarette smoke-induced lung disease characterized by the loss of alveolar structures. This review will discuss oxidative stress, cell death, and other damage to alveolar epithelial cells induced by cigarette smoke.

  11. Prune melanoidins protect against oxidative stress and endothelial cell death.

    Science.gov (United States)

    Posadino, Anna Maria; Cossu, Annalisa; Piga, Antonio; Madrau, Monica Assunta; Del Caro, Alessandra; Colombino, Maria; Paglietti, Bianca; Rubino, Salvatore; Iaccarino, Ciro; Crosio, Claudia; Sanna, Bastiano; Pintus, Gianfranco

    2011-06-01

    The health-promoting effects of fruit and vegetable consumption are thought to be due to phytochemicals contained in fresh plant material. Whether processed plant foods provide the same benefits as unprocessed ones is an open question. Melanoidins from heat-processed plums (prunes) were isolated and their presence confirmed by hydroxymethylfurfural content and browning index. Oxidative-induced endothelial cell (EC) damage is the trigger for the development of cardiovascular diseases (CVD); therefore the potential protective effect of prune melanoidins on hydrogen peroxide-induced oxidative cell damage was investigated on human endothelial ECV304 cells. Cytoplasmic and mitochondrial redox status was assessed by using the novel, redox-sensitive, ratiometric fluorescent protein sensor (roGFP), while mitochondrial membrane potential (MMP) was investigated with the fluorescent dye, JC-1. Treatment of ECV304 cells with hydrogen peroxide dose-dependently induced both mitochondrial and cytoplasmic oxidation, in addition to MMP dissipation, with ensuing cell death. Pretreatment of ECV304 with prune melanoidins, significantly counteracted and ultimately abolished hydrogen peroxide elicited phenomena, clearly indicating that these polymers protect human EC against oxidative stress.

  12. Trichodermin induces cell apoptosis through mitochondrial dysfunction and endoplasmic reticulum stress in human chondrosarcoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Su, Chen-Ming [Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China); Wang, Shih-Wei [Department of Medicine, Mackay Medical College, New Taipei City, Taiwan (China); Lee, Tzong-Huei [Graduate Institute of Pharmacognosy, Taipei Medical University, Taipei, Taiwan (China); Tzeng, Wen-Pei [Graduate Institute of Sports and Health, National Changhua University of Education, Changhua, Taiwan (China); Hsiao, Che-Jen [School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan (China); Liu, Shih-Chia [Department of Orthopaedics, Mackay Memorial Hospital, Taipei, Taiwan (China); Tang, Chih-Hsin, E-mail: chtang@mail.cmu.edu.tw [Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan (China); Department of Pharmacology, School of Medicine, China Medical University, Taichung, Taiwan (China); Department of Biotechnology, College of Health Science, Asia University, Taichung, Taiwan (China)

    2013-10-15

    Chondrosarcoma is the second most common primary bone tumor, and it responds poorly to both chemotherapy and radiation treatment. Nalanthamala psidii was described originally as Myxosporium in 1926. This is the first study to investigate the anti-tumor activity of trichodermin (trichothec-9-en-4-ol, 12,13-epoxy-, acetate), an endophytic fungal metabolite from N. psidii against human chondrosarcoma cells. We demonstrated that trichodermin induced cell apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353 cells) instead of primary chondrocytes. In addition, trichodermin triggered endoplasmic reticulum (ER) stress protein levels of IRE1, p-PERK, GRP78, and GRP94, which were characterized by changes in cytosolic calcium levels. Furthermore, trichodermin induced the upregulation of Bax and Bid, the downregulation of Bcl-2, and the dysfunction of mitochondria, which released cytochrome c and activated caspase-3 in human chondrosarcoma. In addition, animal experiments illustrated reduced tumor volume, which led to an increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and an increased level of cleaved PARP protein following trichodermin treatment. Together, this study demonstrates that trichodermin is a novel anti-tumor agent against human chondrosarcoma cells both in vitro and in vivo via mitochondrial dysfunction and ER stress. - Highlights: • Trichodermin induces chondrosarcoma apoptosis. • ER stress is involved in trichodermin-induced cell death. • Trichodermin induces chondrosarcoma death in vivo.

  13. Application de la diffraction des rayons X in situ à haute température pour l'identification d'une nouvelle phase lors de l'oxydation à 900circC de l'acier 304

    Science.gov (United States)

    Riffard, F.; Buscail, H.; Caudron, E.; Cueff, R.; Issartel, C.; El Messki, S.; Perrier, S.

    2004-11-01

    Une nouvelle interprétation du comportement atypique couramment appelé "breakaway" observé lors de l'oxydation à haute température d'alliages chromino-formeurs est proposée grâce à l'utilisation de la diffraction des rayons X in situ à haute température. L'acier chromino-formeur AISI 304 doit établir une couche d'oxyde superficielle généralement dense et majoritairement, constituée de chromine, dont la vitesse de croissance est lente, afin d'assurer sa protection contre la corrosion à haute température. Cette faible vitesse de croissance de la couche d'oxyde est effectivement observée à 1000circC. Elle serait favorisée par l'établissement d'une couche de chromine induite par la présence d'une sous-couche continue de silice à l'interface interne. Cette dernière limiterait la diffusion du fer. Le phénomène du "breakaway" est observé à la température de 900circC après 40 heures d'oxydation. Ce phénomène serait lié à la croissance initiale d'oxydes contenant du fer. L'oxyde Fe{7}SiO{10, }a été identifié{ }pour la première fois grâce à la technique de diffraction des rayons X in situ à haute température. Cet oxyde semble piéger le silicium dans la couche d'oxyde, empêchant son accumulation à l'interface interne et la formation d'une couche continue de silice.

  14. Oxidative stress in NSC-741909-induced apoptosis of cancer cells

    Directory of Open Access Journals (Sweden)

    Huang Peng

    2010-04-01

    Full Text Available Abstract Background NSC-741909 is a novel anticancer agent that can effectively suppress the growth of several cell lines derived from lung, colon, breast, ovarian, and kidney cancers. We recently showed that NSC-741909-induced antitumor activity is associated with sustained Jun N-terminal kinase (JNK activation, resulting from suppression of JNK dephosphorylation associated with decreased protein levels of MAPK phosphatase-1. However, the mechanisms of NSC-741909-induced antitumor activity remain unclear. Because JNK is frequently activated by oxidative stress in cells, we hypothesized that reactive oxygen species (ROS may be involved in the suppression of JNK dephosphorylation and the cytotoxicity of NSC-741909. Methods The generation of ROS was measured by using the cell-permeable nonfluorescent compound H2DCF-DA and flow cytometry analysis. Cell viability was determined by sulforhodamine B assay. Western blot analysis, immunofluorescent staining and flow cytometry assays were used to determine apoptosis and molecular changes induced by NSC-741909. Results Treatment with NSC-741909 induced robust ROS generation and marked MAPK phosphatase-1 and -7 clustering in NSC-741909-sensitive, but not resistant cell lines, in a dose- and time-dependent manner. The generation of ROS was detectable as early as 30 min and ROS levels were as high as 6- to 8-fold above basal levels after treatment. Moreover, the NSC-741909-induced ROS generation could be blocked by pretreatment with antioxidants, such as nordihydroguaiaretic acid, aesculetin, baicalein, and caffeic acid, which in turn, inhibited the NSC-741909-induced JNK activation and apoptosis. Conclusion Our results demonstrate that the increased ROS production was associated with NSC-741909-induced antitumor activity and that ROS generation and subsequent JNK activation is one of the primary mechanisms of NSC-741909-mediated antitumor cell activity.

  15. Mechanical stress is communicated between different cell types to elicit matrix remodeling

    OpenAIRE

    Swartz, M. A.; Tschumperlin, D. J.; Kamm, R.D.; Drazen, J M

    2001-01-01

    Tissue remodeling often reflects alterations in local mechanical conditions and manifests as an integrated response among the different cell types that share, and thus cooperatively manage, an extracellular matrix. Here we examine how two different cell types, one that undergoes the stress and the other that primarily remodels the matrix, might communicate a mechanical stress by using airway cells as a representative in vitro system. Normal stress is imposed on bro...

  16. Cell membrane stability in two barley genotypes under water stress conditions

    OpenAIRE

    Hanna Bandurska; Halina Gniazdowska-Skoczek

    2014-01-01

    The effect of water stress induced in vitro by polyethylene glycol 6000 (PEG) and under drought stress on cell membrane stability was examined in two barley genotypes, the cultivar Aramir and line R567. The injury of cell membranes was markely influenced by leaf age, leaf position on the stem, and the degree of drought stress. The differences in percentage of injury to cell membrane between these genotypes were also found. The cv. Aramir exhibited a lower percentage injury value as compared t...

  17. A shift to organismal stress resistance in programmed cell death mutants.

    Directory of Open Access Journals (Sweden)

    Meredith E Judy

    Full Text Available Animals have many ways of protecting themselves against stress; for example, they can induce animal-wide, stress-protective pathways and they can kill damaged cells via apoptosis. We have discovered an unexpected regulatory relationship between these two types of stress responses. We find that C. elegans mutations blocking the normal course of programmed cell death and clearance confer animal-wide resistance to a specific set of environmental stressors; namely, ER, heat and osmotic stress. Remarkably, this pattern of stress resistance is induced by mutations that affect cell death in different ways, including ced-3 (cell death defective mutations, which block programmed cell death, ced-1 and ced-2 mutations, which prevent the engulfment of dying cells, and progranulin (pgrn-1 mutations, which accelerate the clearance of apoptotic cells. Stress resistance conferred by ced and pgrn-1 mutations is not additive and these mutants share altered patterns of gene expression, suggesting that they may act within the same pathway to achieve stress resistance. Together, our findings demonstrate that programmed cell death effectors influence the degree to which C. elegans tolerates environmental stress. While the mechanism is not entirely clear, it is intriguing that animals lacking the ability to efficiently and correctly remove dying cells should switch to a more global animal-wide system of stress resistance.

  18. Geometric effects in microfluidics on heterogeneous cell stress using an Eulerian-Lagrangian approach.

    Science.gov (United States)

    Warren, K M; Mpagazehe, J N; LeDuc, P R; Higgs, C F

    2016-02-01

    The response of individual cells at the micro-scale in cell mechanics is important in understanding how they are affected by changing environments. To control cell stresses, microfluidics can be implemented since there is tremendous control over the geometry of the devices. Designing microfluidic devices to induce and manipulate stress levels on biological cells can be aided by computational modeling approaches. Such approaches serve as an efficient precursor to fabricating various microfluidic geometries that induce predictable levels of stress on biological cells, based on their mechanical properties. Here, a three-dimensional, multiphase computational fluid dynamics (CFD) modeling approach was implemented for soft biological materials. The computational model incorporates the physics of the particle dynamics, fluid dynamics and solid mechanics, which allows us to study how stresses affect the cells. By using an Eulerian-Lagrangian approach to treat the fluid domain as a continuum in the microfluidics, we are conducting studies of the cells' movement and the stresses applied to the cell. As a result of our studies, we were able to determine that a channel with periodically alternating columns of obstacles was capable of stressing cells at the highest rate, and that microfluidic systems can be engineered to impose heterogenous cell stresses through geometric configuring. We found that when using controlled geometries of the microfluidics channels with staggered obstructions, we could increase the maximum cell stress by nearly 200 times over cells flowing through microfluidic channels with no obstructions. Incorporating computational modeling in the design of microfluidic configurations for controllable cell stressing could help in the design of microfludic devices for stressing cells such as cell homogenizers. PMID:26753780

  19. Shear Stress Inhibits Apoptosis of Ischemic Brain Microvascular Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Xiafeng Shen

    2013-01-01

    Full Text Available As a therapeutic strategy for ischemic stroke, to restore or increase cerebral blood flow (CBF is the most fundamental option. Laminar shear stress (LS, as an important force generated by CBF, mainly acts on brain microvascular endothelial cells (BMECs. In order to study whether LS was a protective factor in stroke, we investigated LS-intervented ischemic apoptosis of rat BMECs (rBMECs through PE Annexin V/7-AAD, JC-1 and Hoechst 33258 staining to observe the membranous, mitochondrial and nuclear dysfunction. Real-time PCR and western blot were also used to test the gene and protein expressions of Tie-2, Bcl-2 and Akt, which were respectively related to maintain membranous, mitochondrial and nuclear norm. The results showed that LS could be a helpful stimulus for ischemic rBMECs survival. Simultaneously, membranous, mitochondrial and nuclear regulation played an important role in this process.

  20. Inherent ER stress in pancreatic islet β cells causes self-recognition by autoreactive T cells in type 1 diabetes.

    Science.gov (United States)

    Marré, Meghan L; Profozich, Jennifer L; Coneybeer, Jorge T; Geng, Xuehui; Bertera, Suzanne; Ford, Michael J; Trucco, Massimo; Piganelli, Jon D

    2016-08-01

    Type 1 diabetes (T1D) is an autoimmune disease characterized by pancreatic β cell destruction induced by islet reactive T cells that have escaped central tolerance. Many physiological and environmental triggers associated with T1D result in β cell endoplasmic reticulum (ER) stress and dysfunction, increasing the potential for abnormal post-translational modification (PTM) of proteins. We hypothesized that β cell ER stress induced by environmental and physiological conditions generates abnormally-modified proteins for the T1D autoimmune response. To test this hypothesis we exposed the murine CD4(+) diabetogenic BDC2.5 T cell clone to murine islets in which ER stress had been induced chemically (Thapsigargin). The BDC2.5 T cell IFNγ response to these cells was significantly increased compared to non-treated islets. This β cell ER stress increased activity of the calcium (Ca(2+))-dependent PTM enzyme tissue transglutaminase 2 (Tgase2), which was necessary for full stress-dependent immunogenicity. Indeed, BDC2.5 T cells responded more strongly to their antigen after its modification by Tgase2. Finally, exposure of non-antigenic murine insulinomas to chemical ER stress in vitro or physiological ER stress in vivo caused increased ER stress and Tgase2 activity, culminating in higher BDC2.5 responses. Thus, β cell ER stress induced by chemical and physiological triggers leads to β cell immunogenicity through Ca(2+)-dependent PTM. These findings elucidate a mechanism of how β cell proteins are modified and become immunogenic, and reveal a novel opportunity for preventing β cell recognition by autoreactive T cells. PMID:27173406

  1. Molecular biology of the stress response in the early embryo and its stem cells.

    Science.gov (United States)

    Puscheck, Elizabeth E; Awonuga, Awoniyi O; Yang, Yu; Jiang, Zhongliang; Rappolee, Daniel A

    2015-01-01

    Stress is normal during early embryogenesis and transient, elevated stress is commonplace. Stress in the milieu of the peri-implantation embryo is a summation of maternal hormones, and other elements of the maternal milieu, that signal preparedness for development and implantation. Examples discussed here are leptin, adrenaline, cortisol, and progesterone. These hormones signal maternal nutritional status and provide energy, but also signal stress that diverts maternal and embryonic energy from an optimal embryonic developmental trajectory. These hormones communicate endocrine maternal effects and local embryonic effects although signaling mechanisms are not well understood. Other in vivo stresses affect the embryo such as local infection and inflammation, hypoxia, environmental toxins such as benzopyrene, dioxin, or metals, heat shock, and hyperosmotic stress due to dehydration or diabetes. In vitro, stresses include shear during handling, improper culture media and oxygen levels, cryopreservation, and manipulations of the embryo to introduce sperm or mitochondria. We define stress as any stimulus that slows stem cell accumulation or diminishes the ability of cells to produce normal and sufficient parenchymal products upon differentiation. Thus stress deflects downwards the normal trajectories of development, growth and differentiation. Typically stress is inversely proportional to embryonic developmental and proliferative rates, but can be proportional to induction of differentiation of stem cells in the peri-implantation embryo. When modeling stress it is most interesting to produce a 'runting model' where stress exposures slow accumulation but do not create excessive apoptosis or morbidity. Windows of stress sensitivity may occur when major new embryonic developmental programs require large amounts of energy and are exacerbated if nutritional flow decreases and removes energy from the normal developmental programs and stress responses. These windows correspond

  2. Cell shape, spreading symmetry, and the polarization of stress-fibers in cells

    Science.gov (United States)

    Zemel, A.; Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.

    2010-05-01

    The active regulation of cellular forces during cell adhesion plays an important role in the determination of cell size, shape, and internal structure. While on flat, homogeneous and isotropic substrates some cells spread isotropically, others spread anisotropically and assume elongated structures. In addition, in their native environment as well as in vitro experiments, the cell shape and spreading asymmetry can be modulated by the local distribution of adhesive molecules and topography of the environment. We present a simple elastic model and experiments on stem cells to explain the variation of cell size with the matrix rigidity. In addition, we predict the experimental consequences of two mechanisms of acto-myosin polarization and focus here on the effect of the cell spreading asymmetry on the regulation of the stress-fiber alignment in the cytoskeleton. We show that when cell spreading is sufficiently asymmetric the alignment of acto-myosin forces in the cell increases monotonically with the matrix rigidity; however, in general this alignment is non-monotonic, as shown previously. These results highlight the importance of the symmetry characteristics of cell spreading in the regulation of cytoskeleton structure and suggest a mechanism by which different cell types may acquire different morphologies and internal structures in different mechanical environments.

  3. Cell shape, spreading symmetry, and the polarization of stress-fibers in cells

    Energy Technology Data Exchange (ETDEWEB)

    Zemel, A [Institute of Dental Sciences, Faculty of Dental Medicine, and the Fritz Haber Center for Molecular Dynamics, Hebrew University-Hadassah Medical Center, Jerusalem, 91120 (Israel); Rehfeldt, F [III. Physikalisches Institut, Georg-August-Universitaet, 37077 Goettingen (Germany); Brown, A E X [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Discher, D E [Graduate Group of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Safran, S A [Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100 (Israel)

    2010-05-19

    The active regulation of cellular forces during cell adhesion plays an important role in the determination of cell size, shape, and internal structure. While on flat, homogeneous and isotropic substrates some cells spread isotropically, others spread anisotropically and assume elongated structures. In addition, in their native environment as well as in vitro experiments, the cell shape and spreading asymmetry can be modulated by the local distribution of adhesive molecules and topography of the environment. We present a simple elastic model and experiments on stem cells to explain the variation of cell size with the matrix rigidity. In addition, we predict the experimental consequences of two mechanisms of acto-myosin polarization and focus here on the effect of the cell spreading asymmetry on the regulation of the stress-fiber alignment in the cytoskeleton. We show that when cell spreading is sufficiently asymmetric the alignment of acto-myosin forces in the cell increases monotonically with the matrix rigidity; however, in general this alignment is non-monotonic, as shown previously. These results highlight the importance of the symmetry characteristics of cell spreading in the regulation of cytoskeleton structure and suggest a mechanism by which different cell types may acquire different morphologies and internal structures in different mechanical environments.

  4. Light scattering and cell volumes in osmotically stressed and frozen-thawed cells.

    Science.gov (United States)

    McGann, L E; Walterson, M L; Hogg, L M

    1988-01-01

    Recent reports, indicating that under some conditions the intensity of light scattering from cells is a nonlinear function of cell volume, have led to the widespread generalization that intensity of low-angle light scattering indicates cell size. This study was performed to measure the relationships between light scattering and cell volumes in an-isotonic solutions and after a freeze-thaw stress. Cell volumes in isolated human lymphocytes, human granulocytes, and hamster fibroblasts were deliberately altered by exposure to anisotonic solutions. Boyle-vant Hoff plots of cell volume as a function of inverse osmotic pressure showed that the cells behaved as osmometers. Similar plots of right-angle and low-angle light scattering showed that the intensity of light scattering varied inversely with cell volume. In other experiments where cells were frozen without cryoprotectant at various sub zero temperatures to -25 degrees C and then thawed rapidly, cell viability decreased progressively with decreasing temperature, as did the intensity of both low-angle and right-angle light scattering, although cell volumes remained relatively constant. The intensity of both low- and high-angle light scattering varied inversely with cell volumes in hypertonic and hypotonic solutions, but cell damage induced by freezing and thawing resulted in significant reductions in the intensity of low-angle light scattering with little change in cell volume. These observations show that light scattering and cell volumes can vary independently, and they underline the need for a better understanding of the phenomenon of light scattering from living cells. PMID:3409784

  5. Epithelial-mesenchymal transition induces endoplasmic-reticulum-stress response in human colorectal tumor cells.

    Directory of Open Access Journals (Sweden)

    Evelyn Zeindl-Eberhart

    Full Text Available Tumor cells are stressed by unfavorable environmental conditions like hypoxia or starvation. Driven by the resulting cellular stress tumor cells undergo epithelial-mesenchymal transition. Additionally, cellular stress is accompanied by endoplasmic reticulum-stress which induces an unfolded protein response. It is unknown if epithelial-mesenchymal transition and endoplasmic reticulum-stress are occurring as independent parallel events or if an interrelationship exists between both of them. Here, we show that in colorectal cancer cells endoplasmic reticulum-stress depends on the induction of ZEB-1, which is a main factor of epithelial-mesenchymal transition. In the absence of ZEB-1 colorectal cancer cells cannot mount endoplasmic reticulum-stress as a reaction on cellular stress situations like hypoxia or starvation. Thus, our data suggest that there is a hierarchy in the development of cellular stress which starts with the presence of environmental stress that induces epithelial-mesenchymal transition which allows finally endoplasmic reticulum-stress. This finding highlights the central role of epithelial-mesenchymal transition during the process of tumorigenesis as epithelial-mesenchymal transition is also associated with chemoresistance and cancer stemness. Consequently, endoplasmic reticulum-stress might be a well suited target for chemotherapy of colorectal cancers.

  6. Amnion-Epithelial-Cell-Derived Exosomes Demonstrate Physiologic State of Cell under Oxidative Stress.

    Science.gov (United States)

    Sheller, Samantha; Papaconstantinou, John; Urrabaz-Garza, Rheanna; Richardson, Lauren; Saade, George; Salomon, Carlos; Menon, Ramkumar

    2016-01-01

    At term, the signals of fetal maturity and feto-placental tissue aging prompt uterine readiness for delivery by transitioning quiescent myometrium to an active stage. It is still unclear how the signals reach the distant myometrium. Exosomes are a specific type of extracellular vesicle (EVs) that transport molecular signals between cells, and are released from a wide range of cells, including the maternal and fetal cells. In this study, we hypothesize that i) exosomes act as carriers of signals in utero-placental compartments and ii) exosomes reflect the physiologic status of the origin cells. The primary aims of this study were to determine exosomal contents in exosomes derived from primary amnion epithelial cells (AEC). We also determined the effect of oxidative stress on AEC derived exosomal cargo contents. AEC were isolated from amniotic membrane obtained from normal, term, not in labor placentae at delivery, and culture under standard conditions. Oxidative stress was induced using cigarette smoke extract for 48 hours. AEC-conditioned media were collected and exosomes isolated by differential centrifugations. Both growth conditions (normal and oxidative stress induced) produced cup shaped exosomes of around 50 nm, expressed exosomes enriched markers, such as CD9, CD63, CD81 and HSC70, embryonic stem cell marker Nanog, and contained similar amounts of cell free AEC DNA. Using confocal microscopy, the colocalization of histone (H) 3, heat shock protein (HSP) 70 and activated form of pro-senescence and term parturition associated marker p38 mitogen activated protein kinase (MAPK) (P-p38 MAPK) co-localized with exosome enrich marker CD9. HSP70 and P-p38 MAPK were significantly higher in exosomes from AEC grown under oxidative stress conditions than standard conditions (pmass spectrometry and bioinformatics analysis identified 221 different proteins involved in immunomodulatory response and cell-to-cell communication. This study determined AEC exosome

  7. Transcriptome Analysis of Piperlongumine-Treated Human Pancreatic Cancer Cells Reveals Involvement of Oxidative Stress and Endoplasmic Reticulum Stress Pathways.

    Science.gov (United States)

    Dhillon, Harsharan; Mamidi, Sujan; McClean, Phillip; Reindl, Katie M

    2016-06-01

    Piperlongumine (PL), an alkaloid obtained from long peppers, displays antitumorigenic properties for a variety of human cell- and animal-based models. The aim of this study was to identify the underlying molecular mechanisms for PL anticancer effects on human pancreatic cancer cells. RNA sequencing (RNA-seq) was used to identify the effects of PL on the transcriptome of MIA PaCa-2 human pancreatic cancer cells. PL treatment of pancreatic cancer cells resulted in differential expression of 683 mRNA transcripts with known protein functions, 351 of which were upregulated and 332 of which were downregulated compared to control-treated cells. Transcripts associated with oxidative stress, endoplasmic reticulum (ER) stress, and unfolded protein response pathways were significantly overexpressed with PL treatment. Reverse transcription-quantitative polymerase chain reaction and western blotting were used to validate the RNA-seq results, which included upregulation of HO-1, IRE1α, cytochrome c, and ASNS. The results provide key insight into the mechanisms by which PL alters cancer cell physiology and identify that activation of oxidative stress and ER stress pathways is a critical avenue for PL anticancer effects. PMID:27119744

  8. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    OpenAIRE

    Márcia de Mello Luvielmo; Caroline Dellinghausen Borges; Daniela de Oliveira Toyama; Claire Tondo Vendruscolo; Adilma Regina Pippa Scamparini

    2016-01-01

    Abstract The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on g...

  9. A model for cell density effect on stress fiber alignment and collective directional migration.

    Science.gov (United States)

    Abeddoust, Mohammad; Shamloo, Amir

    2015-12-01

    In this study, numerical simulation of collective cell migration is presented in order to mimic the group migration of endothelial cells subjected to the concentration gradients of a biochemical factor. The developed 2D model incorporates basic elements of the cell, including both the cell membrane and the cell cytoskeleton, based on a viscoelastic cell mechanic model. Various cell processes--including cell random walk, cell-cell interactions, cell chemotaxis, and cellular cytoskeleton rearrangements--are considered and analyzed in our developed model. After validating the model by using available experimental data, the model is used to investigate various important parameters during collective cell chemotaxis, such as cell density, cytoskeleton organization, stress fiber reorientations, and intracellular forces. The results suggest that increasing the cell density causes the cell-cell interactions to affect the orientation of stress fibers throughout the cytoskeleton and makes the stress fibers more aligned in the direction of the imposed concentration gradient. This improved alignment of the stress fibers correlates with the intensification of the intracellular forces transferred in the gradient direction; this improves the cell group migration. Comparison of the obtained results with available experimental observations of collective chemotaxis of endothelial cells shows an interesting agreement. PMID:26717999

  10. Adaptive and Pathogenic Responses to Stress by Stem Cells during Development

    Directory of Open Access Journals (Sweden)

    Daniel A. Rappolee

    2012-12-01

    Full Text Available Cellular stress is the basis of a dose-dependent continuum of responses leading to adaptive health or pathogenesis. For all cells, stress leads to reduction in macromolecular synthesis by shared pathways and tissue and stress-specific homeostatic mechanisms. For stem cells during embryonic, fetal, and placental development, higher exposures of stress lead to decreased anabolism, macromolecular synthesis and cell proliferation. Coupled with diminished stem cell proliferation is a stress-induced differentiation which generates minimal necessary function by producing more differentiated product/cell. This compensatory differentiation is accompanied by a second strategy to insure organismal survival as multipotent and pluripotent stem cells differentiate into the lineages in their repertoire. During stressed differentiation, the first lineage in the repertoire is increased and later lineages are suppressed, thus prioritized differentiation occurs. Compensatory and prioritized differentiation is regulated by at least two types of stress enzymes. AMP-activated protein kinase (AMPK which mediates loss of nuclear potency factors and stress-activated protein kinase (SAPK that does not. SAPK mediates an increase in the first essential lineage and decreases in later lineages in placental stem cells. The clinical significance of compensatory and prioritized differentiation is that stem cell pools are depleted and imbalanced differentiation leads to gestational diseases and long term postnatal pathologies.

  11. Adaptive and Pathogenic Responses to Stress by Stem Cells during Development.

    Science.gov (United States)

    Mansouri, Ladan; Xie, Yufen; Rappolee, Daniel A

    2012-01-01

    Cellular stress is the basis of a dose-dependent continuum of responses leading to adaptive health or pathogenesis. For all cells, stress leads to reduction in macromolecular synthesis by shared pathways and tissue and stress-specific homeostatic mechanisms. For stem cells during embryonic, fetal, and placental development, higher exposures of stress lead to decreased anabolism, macromolecular synthesis and cell proliferation. Coupled with diminished stem cell proliferation is a stress-induced differentiation which generates minimal necessary function by producing more differentiated product/cell. This compensatory differentiation is accompanied by a second strategy to insure organismal survival as multipotent and pluripotent stem cells differentiate into the lineages in their repertoire. During stressed differentiation, the first lineage in the repertoire is increased and later lineages are suppressed, thus prioritized differentiation occurs. Compensatory and prioritized differentiation is regulated by at least two types of stress enzymes. AMP-activated protein kinase (AMPK) which mediates loss of nuclear potency factors and stress-activated protein kinase (SAPK) that does not. SAPK mediates an increase in the first essential lineage and decreases in later lineages in placental stem cells. The clinical significance of compensatory and prioritized differentiation is that stem cell pools are depleted and imbalanced differentiation leads to gestational diseases and long term postnatal pathologies.

  12. Salt stress-induced cell death in the unicellular green alga Micrasterias denticulata.

    Science.gov (United States)

    Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lütz, Cornelius; Lütz-Meindl, Ursula

    2009-01-01

    Programmed cell death (PCD) is a key element in normal plant growth and development which may also be induced by various abiotic and biotic stress factors including salt stress. In the present study, morphological, biochemical, and physiological responses of the theoretically immortal unicellular freshwater green alga Micrasterias denticulata were examined after salt (200 mM NaCl or 200 mM KCl) and osmotic stress induced by iso-osmotic sorbitol. KCl caused morphological changes such as cytoplasmic vacuolization, extreme deformation of mitochondria, and ultrastructural changes of Golgi and ER. However, prolonged salt stress (24 h) led to the degradation of organelles by autophagy, a special form of PCD, both in NaCl- and KCl-treated cells. This was indicated by the enclosure of organelles by ER-derived double membranes. DNA of NaCl- and KCl-stressed cells but not of sorbitol-treated cells showed a ladder-like pattern on agarose gel, which means that the ionic rather than the osmotic component of salt stress leads to the activation of the responsible endonuclease. DNA laddering during salt stress could be abrogated by addition of Zn(2+). Neither cytochrome c release from mitochondria nor increase in caspase-3-like activity occurred after salt stress. Reactive oxygen species could be detected within 5 min after the onset of salt and osmotic stress. Respiration, photosynthetic activity, and pigment composition indicated an active metabolism which supports programmed rather than necrotic cell death in Micrasterias after salt stress. PMID:19213813

  13. Salt stress-induced cell death in the unicellular green alga Micrasterias denticulata

    Science.gov (United States)

    Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lütz, Cornelius; Lütz-Meindl, Ursula

    2009-01-01

    Programmed cell death (PCD) is a key element in normal plant growth and development which may also be induced by various abiotic and biotic stress factors including salt stress. In the present study, morphological, biochemical, and physiological responses of the theoretically immortal unicellular freshwater green alga Micrasterias denticulata were examined after salt (200 mM NaCl or 200 mM KCl) and osmotic stress induced by iso-osmotic sorbitol. KCl caused morphological changes such as cytoplasmic vacuolization, extreme deformation of mitochondria, and ultrastructural changes of Golgi and ER. However, prolonged salt stress (24 h) led to the degradation of organelles by autophagy, a special form of PCD, both in NaCl- and KCl-treated cells. This was indicated by the enclosure of organelles by ER-derived double membranes. DNA of NaCl- and KCl-stressed cells but not of sorbitol-treated cells showed a ladder-like pattern on agarose gel, which means that the ionic rather than the osmotic component of salt stress leads to the activation of the responsible endonuclease. DNA laddering during salt stress could be abrogated by addition of Zn2+. Neither cytochrome c release from mitochondria nor increase in caspase-3-like activity occurred after salt stress. Reactive oxygen species could be detected within 5 min after the onset of salt and osmotic stress. Respiration, photosynthetic activity, and pigment composition indicated an active metabolism which supports programmed rather than necrotic cell death in Micrasterias after salt stress. PMID:19213813

  14. Salt Stress-induced Programmed Cell Death in Rice Root Tip Cells

    Institute of Scientific and Technical Information of China (English)

    Jian-You Li; Ai-Liang Jiang; Wei Zhang

    2007-01-01

    Salt stressed rice root tips were used to investigate the changes of reactive oxygen species (ROS) and antioxidant enzymes at the early stages of programmed cell death (PCD). The results indicated that 500 mmol/L NaCl treatment could lead to specific features of PCD in root tips, such as DNA ladder, nuclear condense and deformation, and transferase mediated dUTP nick end labeling positive reaction, which were initiated at 4 h of treatment and progressed thereafter. Cytochrome c release from mitochondria into cytoplasm was also observed, which occurred at 2 h and was earlier than the above nuclear events. In the very early phase of PCD, an immediate burst in hydrogen peroxide and superoxide anion production rate was accompanied by two-phase changes of superoxide dismutases and ascorbate peroxidase. A short period of increase in the activity was followed by prolonged impairment. Thus,we conclude that salt can induce PCD in rice root tip cells, and propose that in the early phase of rice root tip cell PCD, salt stress-induced oxidative burst increased the antioxidant enzyme activity, which, In turn, scavenged the ROS and abrogated PCD. Also, when the stress is prolonged, the antioxidant system is damaged and accumulated ROS induces the PCD process, which leads to cytochrome c release and nuclear change.

  15. Amnion-Epithelial-Cell-Derived Exosomes Demonstrate Physiologic State of Cell under Oxidative Stress

    Science.gov (United States)

    Sheller, Samantha; Papaconstantinou, John; Urrabaz-Garza, Rheanna; Richardson, Lauren; Saade, George; Salomon, Carlos; Menon, Ramkumar

    2016-01-01

    At term, the signals of fetal maturity and feto-placental tissue aging prompt uterine readiness for delivery by transitioning quiescent myometrium to an active stage. It is still unclear how the signals reach the distant myometrium. Exosomes are a specific type of extracellular vesicle (EVs) that transport molecular signals between cells, and are released from a wide range of cells, including the maternal and fetal cells. In this study, we hypothesize that i) exosomes act as carriers of signals in utero-placental compartments and ii) exosomes reflect the physiologic status of the origin cells. The primary aims of this study were to determine exosomal contents in exosomes derived from primary amnion epithelial cells (AEC). We also determined the effect of oxidative stress on AEC derived exosomal cargo contents. AEC were isolated from amniotic membrane obtained from normal, term, not in labor placentae at delivery, and culture under standard conditions. Oxidative stress was induced using cigarette smoke extract for 48 hours. AEC-conditioned media were collected and exosomes isolated by differential centrifugations. Both growth conditions (normal and oxidative stress induced) produced cup shaped exosomes of around 50 nm, expressed exosomes enriched markers, such as CD9, CD63, CD81 and HSC70, embryonic stem cell marker Nanog, and contained similar amounts of cell free AEC DNA. Using confocal microscopy, the colocalization of histone (H) 3, heat shock protein (HSP) 70 and activated form of pro-senescence and term parturition associated marker p38 mitogen activated protein kinase (MAPK) (P-p38 MAPK) co-localized with exosome enrich marker CD9. HSP70 and P-p38 MAPK were significantly higher in exosomes from AEC grown under oxidative stress conditions than standard conditions (pexosome characteristics and their cargo reflected the physiologic status of the cell of origin and suggests that AEC-derived exosomal p38 MAPK plays a major role in determining the fate of pregnancy

  16. Endoplasmic reticulum stress-induced autophagy determines the susceptibility of melanoma cells to dabrafenib

    Science.gov (United States)

    Ji, Chao; Zhang, Ziping; Chen, Lihong; Zhou, Kunli; Li, Dongjun; Wang, Ping; Huang, Shuying; Gong, Ting; Cheng, Bo

    2016-01-01

    Melanoma is one of the deadliest skin cancers and accounts for most skin-related deaths due to strong resistance to chemotherapy drugs. In the present study, we investigated the mechanisms of dabrafenib-induced drug resistance in human melanoma cell lines A375 and MEL624. Our studies support that both endoplasmic reticulum (ER) stress and autophagy were induced in the melanoma cells after the treatment with dabrafenib. In addition, ER stress-induced autophagy protects melanoma cells from the toxicity of dabrafenib. Moreover, inhibition of both ER stress and autophagy promote the sensitivity of melanoma cells to dabrafenib. Taken together, the data suggest that ER stress-induced autophagy determines the sensitivity of melanoma cells to dabrafenib. These results provide us with promising evidence that the inhibition of autophagy and ER stress could serve a therapeutic effect for the conventional dabrafenib chemotherapy. PMID:27536070

  17. Necdin modulates proliferative cell survival of human cells in response to radiation-induced genotoxic stress

    Directory of Open Access Journals (Sweden)

    Lafontaine Julie

    2012-06-01

    Full Text Available Abstract Background The finite replicative lifespan of cells, termed cellular senescence, has been proposed as a protective mechanism against the proliferation of oncogenically damaged cells, that fuel cancer. This concept is further supported by the induction of premature senescence, a process which is activated when an oncogene is expressed in normal primary cells as well as following intense genotoxic stresses. Thus, deregulation of genes that control this process, like the tumor suppressor p53, may contribute to promoting cancer by allowing cells to bypass senescence. A better understanding of the genes that contribute to the establishment of senescence is therefore warranted. Necdin interacts with p53 and is also a p53 target gene, although the importance of Necdin in the p53 response is not clearly understood. Methods In this study, we first investigated Necdin protein expression during replicative senescence and premature senescence induced by gamma irradiation and by the overexpression of oncogenic RasV12. Gain and loss of function experiments were used to evaluate the contribution of Necdin during the senescence process. Results Necdin expression declined during replicative aging of IMR90 primary human fibroblasts or following induction of premature senescence. Decrease in Necdin expression seemed to be a consequence of the establishment of senescence since the depletion of Necdin in human cells did not induce a senescence-like growth arrest nor a flat morphology or SA-β-galactosidase activity normally associated with senescence. Similarly, overexpression of Necdin did not affect the life span of IMR90 cells. However, we demonstrate that in normal human cells, Necdin expression mimicked the effect of p53 inactivation by increasing radioresistance. Conclusion This result suggests that Necdin potentially attenuate p53 signaling in response to genotoxic stress in human cells and supports similar results describing an inhibitory function

  18. A thermo-mechanical stress prediction model for contemporary planar sodium sulfur (NaS) cells

    Science.gov (United States)

    Jung, Keeyoung; Colker, Jeffrey P.; Cao, Yuzhe; Kim, Goun; Park, Yoon-Cheol; Kim, Chang-Soo

    2016-08-01

    We introduce a comprehensive finite-element analysis (FEA) computational model to accurately predict the thermo-mechanical stresses at heterogeneous joints and components of large-size sodium sulfur (NaS) cells during thermal cycling. Quantification of the thermo-mechanical stress is important because the accumulation of stress during cell assembly and/or operation is one of the critical issues in developing practical planar NaS cells. The computational model is developed based on relevant experimental assembly and operation conditions to predict the detailed stress field of a state-of-the-art planar NaS cell. Prior to the freeze-and-thaw thermal cycle simulation, residual stresses generated from the actual high temperature cell assembly procedures are calculated and implemented into the subsequent model. The calculation results show that large stresses are developed on the outer surface of the insulating header and the solid electrolyte, where component fracture is frequently observed in the experimental cell fabrication process. The impacts of the coefficients of thermal expansion (CTE) of glass materials and the thicknesses of cell container on the stress accumulation are also evaluated to improve the cell manufacturing procedure and to guide the material choices for enhanced thermo-mechanical stability of large-size NaS cells.

  19. Multilineage-differentiating stress-enduring (Muse) cells are a primary source of induced pluripotent stem cells in human fibroblasts

    OpenAIRE

    Wakao, Shohei; Kitada, Masaaki; Kuroda, Yasumasa; Shigemoto, Taeko; Matsuse, Dai; Akashi, Hideo; Tanimura, Yukihiro; Tsuchiyama, Kenichiro; Kikuchi, Tomohiko; Goda, Makoto; Nakahata, Tatsutoshi; Fujiyoshi, Yoshinori; Dezawa, Mari

    2011-01-01

    The stochastic and elite models have been proposed for the mechanism of induced pluripotent stem (iPS) cell generation. In this study we report a system that supports the elite model. We previously identified multilineage-differentiating stress-enduring (Muse) cells in human dermal fibroblasts that are characterized by stress tolerance, expression of pluripotency markers, self-renewal, and the ability to differentiate into endodermal-, mesodermal-, and ectodermal-lineage cells from a single c...

  20. Chemical chaperones reduce ionizing radiation-induced endoplasmic reticulum stress and cell death in IEC-6 cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Lee, Hae-June; Lee, Yoon-Jin [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Jeong, Jae-Hoon [Division of Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of); Kang, Seongman [Division of Life Sciences, Korea University, Seoul 136-701 (Korea, Republic of); Lim, Young-Bin, E-mail: yblim@kirams.re.kr [Division of Radiation Effects, Korea Institute of Radiological and Medical Sciences, Seoul 139-706 (Korea, Republic of)

    2014-07-25

    Highlights: • UPR activation precedes caspase activation in irradiated IEC-6 cells. • Chemical ER stress inducers radiosensitize IEC-6 cells. • siRNAs that targeted ER stress responses ameliorate IR-induced cell death. • Chemical chaperons prevent cell death in irradiated IEC-6 cells. - Abstract: Radiotherapy, which is one of the most effective approaches to the treatment of various cancers, plays an important role in malignant cell eradication in the pelvic area and abdomen. However, it also generates some degree of intestinal injury. Apoptosis in the intestinal epithelium is the primary pathological factor that initiates radiation-induced intestinal injury, but the mechanism by which ionizing radiation (IR) induces apoptosis in the intestinal epithelium is not clearly understood. Recently, IR has been shown to induce endoplasmic reticulum (ER) stress, thereby activating the unfolded protein response (UPR) signaling pathway in intestinal epithelial cells. However, the consequences of the IR-induced activation of the UPR signaling pathway on radiosensitivity in intestinal epithelial cells remain to be determined. In this study, we investigated the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhanced IR-induced caspase 3 activation and DNA fragmentation in intestinal epithelial cells. Knockdown of Xbp1 or Atf6 with small interfering RNA inhibited IR-induced caspase 3 activation. Treatment with chemical chaperones prevented ER stress and subsequent apoptosis in IR-exposed intestinal epithelial cells. Our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Furthermore, inhibiting ER stress may be an effective strategy to prevent IR-induced intestinal injury.

  1. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    DEFF Research Database (Denmark)

    La Rocca, Rosanna; Tallerico, Rossana; Hassan, Almosawy Talib;

    2014-01-01

    treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells......In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were...... between 700–1800 cm-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased...

  2. Do Cells Sense Stress or Strain? Measurement of Cellular Orientation Can Provide a Clue☆

    OpenAIRE

    De, Rumi; Zemel, Assaf; Safran, Samuel A.

    2008-01-01

    We predict theoretically the steady-state orientation of cells subject to dynamical stresses that vary more quickly than the cell relaxation time. We show that the orientation is a strong function of the Poisson's ratio, ν, of the matrix when cell activity is governed by the matrix strain; if cell activity is governed by the matrix stress, the orientation depends only weakly on ν. These results can be used to differentiate systems in which the strain or the stress determine the setpoint for t...

  3. Simulation of thermal and sodium expansion stress in aluminum reduction cells

    Institute of Scientific and Technical Information of China (English)

    LI Jie; WU Yu-yun; LAI Yan-qing; LIU Wei; WANG Zhi-gang; LIU Jie; LIU Ye-xiang

    2008-01-01

    Two finite element(FE) models were built up for analysis of stress field in the lining of aluminum electrolysis cells. Distribution of sodium concentration in cathode carbon blocks was calculated by one FE model of a cathode block. Thermal stress field was calculated by the other slice model of the cell at the end of the heating-up. Then stresses coupling thermal and sodium expansion were considered after 30 d start-up. The results indicate that sodium penetrates to the bottom of the cathode block after 30 d start-up. The semi-graphitic carbon block has the largest stress at the thermal stage. After 30 d start-up the anthracitic carbon has the greatest sodium expansion stress and the graphitized carbon has the lowest sodium expansion stress. Sodium penetration can cause larger deformation and stress in the cathode carbon block than thermal expansion.

  4. Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

    Energy Technology Data Exchange (ETDEWEB)

    Tang, J.; Jiang, Y. [Southern Medical University, Nanfang Hospital, Department of Anesthesia, Guangzhou, China, Department of Anesthesia, Nanfang Hospital, Southern Medical University, Guangzhou (China); Tang, Y.; Chen, B. [Guangzhou General Hospital of Guangzhou Military Command, Department of Intensive Care Unit, Guangzhou, China, Department of Intensive Care Unit, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou (China); Sun, X. [Laboratory of Traditional Chinese Medicine Syndrome, School of Traditional Chinese Medicine, Southern Medical University, Guangzhou (China); Su, L.; Liu, Z. [Guangzhou General Hospital of Guangzhou Military Command, Department of Intensive Care Unit, Guangzhou, China, Department of Intensive Care Unit, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou (China)

    2013-06-25

    Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.

  5. Targeting homeostatic mechanisms of endoplasmic reticulum stress to increase susceptibility of cancer cells to fenretinide-induced apoptosis: the role of stress proteins ERdj5 and ERp57

    OpenAIRE

    Corazzari, M.; Lovat, P E; Armstrong, J L; Fimia, G M; Hill, D S; Birch-Machin, M; Redfern, C P F; Piacentini, M

    2007-01-01

    Endoplasmic reticulum (ER) malfunction, leading to ER stress, can be a consequence of genome instability and hypoxic tissue environments. Cancer cells survive by acquiring or enhancing survival mechanisms to counter the effects of ER stress and these homeostatic responses may be new therapeutic targets. Understanding the links between ER stress and apoptosis may be approached using drugs specifically to target ER stress responses in cancer cells. The retinoid analogue fenretinide [N-(4-hydrox...

  6. Laminar shear stress delivers cell cycle arrest and anti-apoptosis to mesenchymal stem cells

    Institute of Scientific and Technical Information of China (English)

    Wei Luo; Wei Xiong; Jun Zhou; Zhong Fang; Wenjian Chen; Yubo Fan; Feng Li

    2011-01-01

    Biomechanical forces are emerging as critical regulators of cell function and fluid flow is a potent mechanical stimulus. Although the mechanisms of osteoblasts and osteocytes responding to fluid flow are being elucidated,little is known about how the osteoprogenitors, mesenchymal stem cells (MSCs), respond to fluid flow. Here, we examined the effects of laminar shear stress (LSS) on MSCs in vitro. MSCs from bone marrow of SpragueDawley rats were isolated, purified, and subjected to physiological levels of LSS. DNA synthesis and cell cycle were measured through [3H]thymidine and by flow cytometry,respectively, to detect the cellular proliferation. Annexin V immunostaining and Bcl-2/Bax mRNA expression were evaluated to determine the effect of LSS on MSCs apoptosis. Results showed that fluid shear stress caused a doserelated reduction of MSCs' proliferation rate with the majority of cells being arrested in the Go or G1 phase.Moreover, it was found that physiological levels of LSS exerted a potent suppression effect on MSC apoptosis, In summary, these data revealed a critical role of LSS in maintaining the quiescence of MSCs.

  7. Pseudorabies Virus Induces Viability Changes and Oxidative Stress in Swine Testis Cell-Line

    Directory of Open Access Journals (Sweden)

    Xiao-Zhan Zhang§1, Ye Chen§1, Hong-Liang Huang§2, Dong-Lei Xu1, Chang-Bao Ren2, Bi-Tao Liu1, Shuo Su1 and Zhao-Xin Tang1, 2*

    2013-11-01

    Full Text Available In this study, we evaluated the association between pseudorabies (PRV virus-induced viability changes and oxidative stress in vitro cultivated swine testis (ST cells. The kinetic of 2, 12, 24, 36 and 48 h during the cell culture with PRV by using a multiplicity of infection (MOI of 1 TCID50 per cell were adopted. The results suggested a complex relation between cell viability and oxidative stress during PRV infection. In the early stages of PRV infection, the cell viability was higher than the control group, and the state of cellular oxidative stress remained relatively stable. After 24 h, the cell viability began to decrease, and the amount of the cellular malondialdehyde in ST cells increased significantly, and the activities of superoxide dismutase and catalase decreased significantly (P<0.05. Meanwhile, the rising concentrations of cellular hydrogen peroxide were detected prior to the changes in cell viability and oxidative stress. In conclusion, the PRV infection of ST cells leads to oxidative stress, and this stress could play a crucial role on the cell viability as the PRV infection time progresses.

  8. Effect of Varying Fluid Shear Stress on Cancer Stem Cell Viability & Protein Expression

    Science.gov (United States)

    Domier, Ria; Kim, Yonghyun; Dozier, David; Triantafillu, Ursula

    2013-11-01

    Cancer stem cells cultured in vitro in stirred bioreactors are exposed to shear stress. By observing the effect of shear stress on cancer stem cell viability, laboratory cell growth could be optimized. In addition, metastasized cancer stem cells in vivo are naturally exposed to shear stress, a factor influencing stem cell differentiation, while circulating in the bloodstream. Changes in protein expression after exposure to shear stress could allow for identification and targeting of circulating cancer cells. In this study, blood flow through capillaries was simulated by using a syringe pump to inject suspensions of Kasumi-1 leukemia stem cells into model blood vessels composed of PEEK tubing 125 microns in diameter. The Hagen-Poisseuille equation was used to solve for operating flow rates based on specified amounts of shear stress. After exposure, cell counts and viabilities were observed using an optical microscope and proteins were analyzed using Western blotting. It was observed that at a one minute exposure to stress, cell viability increased as the amount of shear was increased from 10 to 60 dynes per square centimeter. Results from this research are applicable to optimization of large-scale stem cell growth in bioreactors as well as to the design of targeted cancer therapies. Funding from NSF REU grant #1062611 is gratefully acknowledged.

  9. Hydrogels with tunable stress relaxation regulate stem cell fate and activity

    Science.gov (United States)

    Chaudhuri, Ovijit; Gu, Luo; Klumpers, Darinka; Darnell, Max; Bencherif, Sidi A.; Weaver, James C.; Huebsch, Nathaniel; Lee, Hong-Pyo; Lippens, Evi; Duda, Georg N.; Mooney, David J.

    2016-03-01

    Natural extracellular matrices (ECMs) are viscoelastic and exhibit stress relaxation. However, hydrogels used as synthetic ECMs for three-dimensional (3D) culture are typically elastic. Here, we report a materials approach to tune the rate of stress relaxation of hydrogels for 3D culture, independently of the hydrogel's initial elastic modulus, degradation, and cell-adhesion-ligand density. We find that cell spreading, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) are all enhanced in cells cultured in gels with faster relaxation. Strikingly, MSCs form a mineralized, collagen-1-rich matrix similar to bone in rapidly relaxing hydrogels with an initial elastic modulus of 17 kPa. We also show that the effects of stress relaxation are mediated by adhesion-ligand binding, actomyosin contractility and mechanical clustering of adhesion ligands. Our findings highlight stress relaxation as a key characteristic of cell-ECM interactions and as an important design parameter of biomaterials for cell culture.

  10. Acute Stress-Induced Changes in Follicular Dermal Papilla Cells and Mobilization of Mast Cells: Implications for Hair Growth

    Science.gov (United States)

    Shin, Hyoseung; Choi, Soon-Jin; Cho, A-Ri; Kim, Dong Young; Kim, Kyu Han

    2016-01-01

    Background Stress is a known cause of hair loss in many species. Objective In this study, we investigated the role of acute stress on hair growth using a rat model. Methods Rats were immobilized for 24 hours and blood samples, and skin biopsies were taken. The effect of stress-serum on the in vitro proliferation of rat and human dermal papilla cells (hDPCs), as well as serum cortisol and corticotropin-releasing hormone levels, were measured. Mast cell staining was performed on the biopsied tissue. In addition, Western blot and quantitative real time polymerase chain reaction were used to assess mast cell tryptase and cytokine expression, respectively in rat skin biopsies. Results Stress-serum treatment reduced significantly the number of viable hDPCs and arrested the cell cycle in the G1 phase, compared to serum from unrestrained rats (phair growth via cortisol release in addition to substance P-mast cell pathway.

  11. Simulation and in situ measurement of stress distribution in a polymer electrolyte membrane fuel cell stack

    Science.gov (United States)

    de la Cruz, Javier; Cano, Ulises; Romero, Tatiana

    2016-10-01

    A critical parameter for PEM fuel cell's electric contact is the nominal clamping pressure. Predicting the mechanical behavior of all components in a fuel cell stack is a very complex task due to the diversity of materials properties. Prior to the integration of a 3 kW PEMFC power plant, a numerical simulation was performed in order to obtain the mechanical stress distribution for two of the most pressure sensitive components of the stack: the membrane, and the graphite plates. The stress distribution of the above mentioned components was numerically simulated by finite element analysis and the stress magnitude for the membrane was confirmed using pressure films. Stress values were found within the elastic zone which guarantees mechanical integrity of fuel cell components. These low stress levels particularly for the membrane will allow prolonging the life and integrity of the fuel cell stack according to its design specifications.

  12. Cell surface estrogen receptor alpha is upregulated during subchronic metabolic stress and inhibits neuronal cell degeneration.

    Directory of Open Access Journals (Sweden)

    Cristiana Barbati

    Full Text Available In addition to the classical nuclear estrogen receptor, the expression of non-nuclear estrogen receptors localized to the cell surface membrane (mER has recently been demonstrated. Estrogen and its receptors have been implicated in the development or progression of numerous neurodegenerative disorders. Furthermore, the pathogenesis of these diseases has been associated with disturbances of two key cellular programs: apoptosis and autophagy. An excess of apoptosis or a defect in autophagy has been implicated in neurodegeneration. The aim of this study was to clarify the role of ER in determining neuronal cell fate and the possible implication of these receptors in regulating either apoptosis or autophagy. The human neuronal cell line SH-SY5Y and mouse neuronal cells in primary culture were thus exposed to chronic minimal peroxide treatment (CMP, a form of subcytotoxic minimal chronic stress previously that mimics multiple aspects of long-term cell stress and represents a limited molecular proxy for neurodegenerative processes. We actually found that either E2 or E2-bovine serum albumin construct (E2BSA, i.e. a non-permeant form of E2 was capable of modulating intracellular cell signals and regulating cell survival and death. In particular, under CMP, the up-regulation of mERα, but not mERβ, was associated with functional signals (ERK phosphorylation and p38 dephosphorylation compatible with autophagic cytoprotection triggering and leading to cell survival. The mERα trafficking appeared to be independent of the microfilament system cytoskeletal network but was seemingly associated with microtubular apparatus network, i.e., to MAP2 molecular chaperone. Importantly, antioxidant treatments, administration of siRNA to ERα, or the presence of antagonist of ERα hindered these events. These results support that the surface expression of mERα plays a pivotal role in determining cell fate, and that ligand-induced activation of mER signalling exerts a

  13. Inflammatory cytokines protect retinal pigment epithelial cells from oxidative stress-induced death

    DEFF Research Database (Denmark)

    Juel, Helene B; Faber, Carsten; Svendsen, Signe Goul;

    2013-01-01

    -cultured with activated T cells, or treated with cytokines showed increased expression of anti-oxidative genes, with upregulation of superoxide dismutase 2 protein following PCM treatment. CONCLUSION: Oxidative stress-induced cell death was reduced by concomitant inflammatory stress. This is likely due to the cytokine......PURPOSE: To investigate the effects of inflammatory factors and oxidative stress on cell survival of the human retinal pigment epithelial (RPE) cell line, ARPE-19. METHODS: Confluent RPE cells were treated with peripheral blood mononuclear cells-conditioned medium (PCM), H2O2, NaIO3, interferon...... expression of anti-oxidative enzymes, and protein expression was validated by immunoblotting. RESULTS: Viability of RPE cells was reduced by exposure to inflammatory agents (PCM, IFNγ+/-TNFα) or to oxidative agents (H2O2 or NaIO3). Unexpectedly, cells treated with either H2O2 or NaIO3 were partially...

  14. Complete relaxation of residual stresses during reduction of solid oxide fuel cells

    DEFF Research Database (Denmark)

    Frandsen, Henrik Lund; Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2015-01-01

    To asses the reliability of solid oxide fuel cell (SOFC) stacks during operation, the stress field in the stack must be known. During operation the stress field will depend on time as creep processes relax stresses. This work reports further details on a newly discovered creep phenomenon...... reduce significantly over minutes. In this work the stresses are measured in-situ before and after the reduction by use of XRD. The phenomenon of accelerated creep has to be considered both in the production of stacks and in the analysis of the stress field in a stack based on anode supported SOFCs....

  15. Lanthanum Prevents Salt Stress-induced Programmed Cell Death in Rice Root Tip Cells by Controlling Early Induction Events

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In a previous study, a salt stress-induced programmed cell death (PCD) model was established in rice root tip cells. Here,by using Wuyunjing 8th rice seedlings, the effects of lanthanum on salt stress-induced PCD early events were studied. The peroxidase (APX). Imidazole (20 mmol/L), the inhibitor of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH oxidase), could alleviate the occurrence of PCD obviously, and such alleviation could be enhanced by the addition of La3+,indicating the involvement of NADPH oxidase in the salt stress-induced PCD process. Taken together, lanthanum could prevent salt stress-induced PCD occurrence in the rice root tip cells by blocking the calcium influx under stress, which was followed by inhibiting calcium-dependent NADPH oxidase activity to prevent O2·-production and, enhancing the cytosolic antioxidative enzyme activities to scavenge the reactive oxygen species.

  16. Beller Lectureship Talk: Active response of biological cells to mechanical stress

    Science.gov (United States)

    Safran, Samuel

    2009-03-01

    Forces exerted by and on adherent cells are important for many physiological processes such as wound healing and tissue formation. In addition, recent experiments have shown that stem cell differentiation is controlled, at least in part, by the elasticity of the surrounding matrix. We present a simple and generic theoretical model for the active response of biological cells to mechanical stress. The theory includes cell activity and mechanical forces as well as random forces as factors that determine the polarizability that relates cell orientation to stress. This allows us to explain the puzzling observation of parallel (or sometimes random) alignment of cells for static and quasi-static stresses and of nearly perpendicular alignment for dynamically varying stresses. In addition, we predict the response of the cellular orientation to a sinusoidally varying applied stress as a function of frequency and compare the theory with recent experiments. The dependence of the cell orientation angle on the Poisson ratio of the surrounding material distinguishes cells whose activity is controlled by stress from those controlled by strain. We have extended the theory to generalize the treatment of elastic inclusions in solids to ''living'' inclusions (cells) whose active polarizability, analogous to the polarizability of non-living matter, results in the feedback of cellular forces that develop in response to matrix stresses. We use this to explain recent observations of the non-monotonic dependence of stress-fiber polarization in stem cells on matrix rigidity. These findings provide a mechanical correlate for the existence of an optimal substrate elasticity for cell differentiation and function. [3pt] *In collaboration with R. De (Brown University), Y. Biton (Weizmann Institute), and A. Zemel (Hebrew University) and the experimental groups: Max Planck Institute, Stuttgart: S. Jungbauer, R. Kemkemer, J. Spatz; University of Pennsylvania: A. Brown, D. Discher, F. Rehfeldt.

  17. Stress

    Science.gov (United States)

    ... Some people experience digestive symptoms. Others may have headaches, sleeplessness, depressed mood, anger, and irritability. People under chronic stress get more frequent and severe viral infections, such ...

  18. Stress-stiffening-mediated stem-cell commitment switch in soft responsive hydrogels

    Science.gov (United States)

    Das, Rajat K.; Gocheva, Veronika; Hammink, Roel; Zouani, Omar F.; Rowan, Alan E.

    2016-03-01

    Bulk matrix stiffness has emerged as a key mechanical cue in stem cell differentiation. Here, we show that the commitment and differentiation of human mesenchymal stem cells encapsulated in physiologically soft (~0.2-0.4 kPa), fully synthetic polyisocyanopeptide-based three-dimensional (3D) matrices that mimic the stiffness of adult stem cell niches and show biopolymer-like stress stiffening, can be readily switched from adipogenesis to osteogenesis by changing only the onset of stress stiffening. This mechanical behaviour can be tuned by simply altering the material’s polymer length whilst maintaining stiffness and ligand density. Our findings introduce stress stiffening as an important parameter that governs stem cell fate in a 3D microenvironment, and reveal a correlation between the onset of stiffening and the expression of the microtubule-associated protein DCAMKL1, thus implicating DCAMKL1 in a stress-stiffening-mediated, mechanotransduction pathway that involves microtubule dynamics in stem cell osteogenesis.

  19. Mitochondrial calcium uniporter protein MCU is involved in oxidative stress-induced cell death.

    Science.gov (United States)

    Liao, Yajin; Hao, Yumin; Chen, Hong; He, Qing; Yuan, Zengqiang; Cheng, Jinbo

    2015-06-01

    Mitochondrial calcium uniporter (MCU) is a conserved Ca(2+) transporter at mitochondrial in eukaryotic cells. However, the role of MCU protein in oxidative stress-induced cell death remains unclear. Here, we showed that ectopically expressed MCU is mitochondrial localized in both HeLa and primary cerebellar granule neurons (CGNs). Knockdown of endogenous MCU decreases mitochondrial Ca(2+) uptake following histamine stimulation and attenuates cell death induced by oxidative stress in both HeLa cells and CGNs. We also found MCU interacts with VDAC1 and mediates VDAC1 overexpression-induced cell death in CGNs. This finding demonstrates that MCU-VDAC1 complex regulates mitochondrial Ca(2+) uptake and oxidative stress-induced apoptosis, which might represent therapeutic targets for oxidative stress related diseases.

  20. Shear stress reduces protease activated receptor-1 expression in human endothelial cells

    Science.gov (United States)

    Nguyen, K. T.; Eskin, S. G.; Patterson, C.; Runge, M. S.; McIntire, L. V.

    2001-01-01

    Shear stress has been shown to regulate several genes involved in the thrombotic and proliferative functions of endothelial cells. Thrombin receptor (protease-activated receptor-1: PAR-1) increases at sites of vascular injury, which suggests an important role for PAR-1 in vascular diseases. However, the effect of shear stress on PAR-1 expression has not been previously studied. This work investigates effects of shear stress on PAR-1 gene expression in both human umbilical vein endothelial cells (HUVECs) and microvascular endothelial cells (HMECs). Cells were exposed to different shear stresses using a parallel plate flow system. Northern blot and flow cytometry analysis showed that shear stress down-regulated PAR-1 messenger RNA (mRNA) and protein levels in both HUVECs and HMECs but with different thresholds. Furthermore, shear-reduced PAR-1 mRNA was due to a decrease of transcription rate, not increased mRNA degradation. Postshear stress release of endothelin-1 in response to thrombin was reduced in HUVECs and HMECs. Moreover, inhibitors of potential signaling pathways applied during shear stress indicated mediation of the shear-decreased PAR-1 expression by protein kinases. In conclusion, shear stress exposure reduces PAR-1 gene expression in HMECs and HUVECs through a mechanism dependent in part on protein kinases, leading to altered endothelial cell functional responses to thrombin.

  1. Le champ critique de claquage de films d'oxyde de polyphénylène réalisés par voie électrochimique

    Science.gov (United States)

    Adohi, B.; Gosse, J. P.; Gosse, B.

    1991-10-01

    The electrical breakdown of thin films of polyphenylene oxide electrochemically deposited on stainless steel plane substrates has been studied. First it was examined the dependence of the medium surrounding the dielectric and the electrodes (nature, hydrostatic pressure) on the breakdown voltage and on its statistical distribution. Between sphere and plane electrodes, it appears that even for pressurified gases, breakdown of the film is caused by the gas breakdown. We have analysed the discharges occurring at atmosphere pressure in the test cell. Breakdown of the film occurred when the electric field due to the charge deposited on its surface was about 230 V/μm. We have also studied self-healing capacitors with PPO as a dielectric, and determined the life-time of this material. On a étudié le claquage électrique de films minces d'oxyde de polyphénylène de quelques microns d'épaisseur déposés par voie électrochimique sur un plan en acier inoxydable. L'étude a d'abord été faite en rampe de tension continue dans la géométrie d'électrodes sphèreplan, en fonction du milieu ambiant liquide ou gazeux. L'influence de la pression sur la rigidité diélectrique du matériau, les distributions statistiques de Weibull et les cratères formés au moment du claquage, dans les différents milieux et dans les deux polarités de l'électrode sphérique montrent que le claquage du matériau est causé par des décharges qui se produisent dans le milieu environnant. A partir de l'analyse quantitative de ces décharges, on propose comme critère de caractérisation de la rupture d'un matériau sounmis aux décharges, le champ créé au moment de la rupture par les charges déposées à sa surface. On a réalisé ensuite des échantillons plans > par dépôt de couches minces d'aluminium (quelques milliers d'Å d'épaisseur) sur le film de PPO. On étudie dans cette configuration la durée de vie du matériau.

  2. Effects of the Curing Process on the Residual Stress in Solar Cell Module

    Directory of Open Access Journals (Sweden)

    Zidu Li

    2016-03-01

    Full Text Available Panels using solar power require high reliability, and the residual stress in the solar panel has an important effect on its reliability and lifetime. The finite element method was adopted to simulate the impacts of the rectangular solar panel encapsulation process parameters, such as the elastic modulus, the thickness of adhesive, and the curing temperature on the residual stress in the solar cell module. The results show that the residual stress in the solar cell module increases linearly with the increase in these three factors. The residual strain is consistent with that of the stress. The generation mechanism and distribution evolution of stress are discussed in detail. Both the thickness and the elastic modulus of the silicone rubber have significant impact on the residual stress. However, the influence of the curing temperature is less observable.

  3. Prolactin mediates effects of chronic psychological stress on induction of fibrofatty cells in the heart.

    Science.gov (United States)

    Song, Jiangping; Wang, Mangyuan; Chen, Xiao; Liu, Li; Chen, Liang; Song, Zhizhao; Teng, Xiao; Xing, Yong; Chen, Kai; Zhao, Kun; Hou, Jianfeng; Yang, Pingchang

    2016-01-01

    Cardiocyte apoptosis plays an important role in the pathogenesis of heart diseases. The mechanism is unclear. It is reported that prolactin (PRL) is involved in cardiac disorders. This study aims to investigate the role of PRL in mediating the psychological stress-induced fibrofatty cell differentiation in the heart. In this study, BALB/c mice were treated with a 30-day restraint stress. The heart tissue was processed by paraffin embedding and hematoxylin and eosin. The expression of Sca1 in NIH3T3 cells was assessed by cell culture, flow cytometry and Western blotting. The results showed that chronic stress induced fibrofatty cells in the mouse heart and high serum PRL levels. The induction of fibrofatty cell was mimicked by administration with recombinant PRL. The stress also induced the expression of Sca1 in the mouse heart. Exposure of NIH3T3 cells (a fibroblast cell line) to PRL in the culture enhanced the expression of stem cell antigen-1 (Sca1), phosphorylation of signal transducer and activator of transcription 3 (STAT3) and expression of adipocyte-related protein molecules, including adiponectin, fatty acid binding protein (aP2), peroxisome proliferator activated receptor-g (PPARg) and CCAAT/enhancer binding protein (C/EBP)α, in the cells. We conclude that psychological stress-derived PRL induces fibroblasts to differentiate into fibrofatty cells in the heart.

  4. Cooperative effects of matrix stiffness and fluid shear stress on endothelial cell behavior.

    Science.gov (United States)

    Kohn, Julie C; Zhou, Dennis W; Bordeleau, François; Zhou, Allen L; Mason, Brooke N; Mitchell, Michael J; King, Michael R; Reinhart-King, Cynthia A

    2015-02-01

    Arterial hemodynamic shear stress and blood vessel stiffening both significantly influence the arterial endothelial cell (EC) phenotype and atherosclerosis progression, and both have been shown to signal through cell-matrix adhesions. However, the cooperative effects of fluid shear stress and matrix stiffness on ECs remain unknown. To investigate these cooperative effects, we cultured bovine aortic ECs on hydrogels matching the elasticity of the intima of compliant, young, or stiff, aging arteries. The cells were then exposed to laminar fluid shear stress of 12 dyn/cm(2). Cells grown on more compliant matrices displayed increased elongation and tighter EC-cell junctions. Notably, cells cultured on more compliant substrates also showed decreased RhoA activation under laminar shear stress. Additionally, endothelial nitric oxide synthase and extracellular signal-regulated kinase phosphorylation in response to fluid shear stress occurred more rapidly in ECs cultured on more compliant substrates, and nitric oxide production was enhanced. Together, our results demonstrate that a signaling cross talk between stiffness and fluid shear stress exists within the vascular microenvironment, and, importantly, matrices mimicking young and healthy blood vessels can promote and augment the atheroprotective signals induced by fluid shear stress. These data suggest that targeting intimal stiffening and/or the EC response to intima stiffening clinically may improve vascular health.

  5. Salt stress-induced cell death in the unicellular green alga Micrasterias denticulata

    OpenAIRE

    Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lütz, Cornelius; LÜTZ-MEINDL, URSULA

    2009-01-01

    Programmed cell death (PCD) is a key element in normal plant growth and development which may also be induced by various abiotic and biotic stress factors including salt stress. In the present study, morphological, biochemical, and physiological responses of the theoretically immortal unicellular freshwater green alga Micrasterias denticulata were examined after salt (200 mM NaCl or 200 mM KCl) and osmotic stress induced by iso-osmotic sorbitol. KCl caused morphological changes such as cytopl...

  6. Preconditioning L6 Muscle Cells with Naringin Ameliorates Oxidative Stress and Increases Glucose Uptake

    OpenAIRE

    R. Dhanya; K B Arun; Nisha, V. M.; Syama, H. P.; Nisha, P.; Santhosh Kumar, T. R.; Jayamurthy, P.

    2015-01-01

    Enhanced oxidative stress contributes to pathological changes in diabetes and its complications. Thus, strategies to reduce oxidative stress may alleviate these pathogenic processes. Herein, we have investigated Naringin mediated regulation of glutathione (GSH) & intracellular free radical levels and modulation of glucose uptake under oxidative stress in L6 cell lines. The results from the study demonstrated a marked decrease in glutathione with a subsequent increase in free radical levels, w...

  7. ET-67SUICIDE GENE THERAPY FOR GLIOMA USING MULTILINEAGE-DEFFERENTIATING STRESS ENDURING (MUSE) CELLS

    OpenAIRE

    Yamasaki, Tomohiro; Wakao, Shohei; KAWAJI, Hiroshi; Suzuki, Tomo; Kamio, Yoshinobu; AMANO, SHINJI; Sameshima, Tetsuro; Sakai, Naoto; TOKUYAMA, TSUTOMU; Dezawa, Mari; NAMBA, HIROKI

    2014-01-01

    INTRODUCTION: We have been investigating cell-based glioma gene therapy using various kinds of stem cells transduced with the herpes simplex virus thymidine kinase gene (HSVtk). In our previous study, we used SSEA3/CD105 double-positive multilineage-differentiating stress-enduring (Muse) cells transduced with HSVtk (Muse-tk cells) as the vehicle for HSVtk/ganciclovir (GCV) gene therapy. We demonstrated a potent in vitro tumoricidal bystander effect for various glioma cells. In the present stu...

  8. Cell-matrix adhesion characterization using multiple shear stress zones in single stepwise microchannel

    Science.gov (United States)

    Kim, Min-Ji; Doh, Il; Bae, Gab-Yong; Cha, Hyuk-Jin; Cho, Young-Ho

    2014-08-01

    This paper presents a cell chip capable to characterize cell-matrix adhesion by monitoring cell detachment rate. The proposed cell chip can supply multiple levels of shear stress in single stepwise microchannel. As epithelial-mesenchymal transition (EMT), one of hallmarks of cancer metastasis is closely associated to the interaction with extracelluar matrix (ECM), we took advantage of two lung cancer cell models with different adhesion properties to ECM depending their epithelial or mesenchymal properties, including the pair of lung cancer cells with (A549sh) or without E-cadherin expression (A549sh-Ecad), which would be optimal model to examine the alteration of adhesion properties after EMT induction. The cell-matrix adhesion resisting to shear stress appeared to be remarkably differed between lung cancer cells. The detachment rate of epithelial-like H358 and mesenchymal-like H460 cells was 53%-80% and 25%-66% in the shear stress range of 34-60 dyn/cm2, respectively. A549sh-Ecad cells exhibits lower detachment rate (5%-9%) compared to A549sh cells (14%-40%). By direct comparison of adhesion between A549sh and A549sh-Ecad, we demonstrated that A549shE-cad to mimic EMT were more favorable to the ECM attachment under the various levels of shear stress. The present method can be applied to quantitative analysis of tumor cell-ECM adhesion.

  9. A Numerical Investigation of the Thermal Stresses of a Planar Solid Oxide Fuel Cell

    Directory of Open Access Journals (Sweden)

    Paulina Pianko-Oprych

    2016-09-01

    Full Text Available A typical operating temperature of a solid oxide fuel cell (SOFC is quite high above 750 °C and affects the thermomechanical behavior of the cell. Thermal stresses may cause microstructural instability and sub-critical cracking. Therefore, a joint analysis by the computational fluid dynamics (CFD and computational structural mechanics based on the finite element method (FEM was carried out to analyze thermal stresses in a planar SOFC and to predict potential failure locations in the cell. A full numerical model was based on the coupling of thermo-fluid model with the thermo-mechanical model. Based on a temperature distribution from the thermo-fluid model, stress distribution including the von Mises stress, shear stress as well as the operating principal stress were derived in the thermo-mechanical model. The FEM calculations were performed under different working conditions of the planar SOFC. The highest total stress was noticed at the lower operating voltage of 0.3 V, while the lowest total stress was determined at the voltage of 0.7 V. The obtained stress distributions allowed a better understanding of details of internal processes occurring within the SOFC and provided helpful guidance in the optimization of a new SOFC design.

  10. NRF2 Oxidative Stress Induced by Heavy Metals is Cell Type Dependent

    Science.gov (United States)

    Exposure to metallic environmental toxicants has been demonstrated to induce a variety of oxidative stress responses in mammalian cells. The transcription factor Nrf2 is activated in response to oxidative stress and coordinates the expression of antioxidant gene products. In this...

  11. THERMOTOLERANCE IN MAMMALIAN-CELLS - PROTEIN DENATURATION AND AGGREGATION, AND STRESS PROTEINS

    NARCIS (Netherlands)

    KAMPINGA, HH

    1993-01-01

    Cells that have been pre-exposed to thermal stress can acquire a transient resistance against the killing effect of a subsequent thermal stress. The cause for this phenomenon, called thermotolerance, seems to be an enhanced resistance of proteins against thermal denaturation and aggregation. This re

  12. Alveolar Type II Cells Escape Stress Failure Caused by Tonic Stretch through Transient Focal Adhesion Disassembly

    Directory of Open Access Journals (Sweden)

    Xiao-Yang Liu, Xiao-Fei Chen, Yan-Hong Ren, Qing-Yuan Zhan, Chen Wang, Chun Yang

    2011-01-01

    Full Text Available Mechanical ventilation-induced excessive stretch of alveoli is reported to induce cellular stress failure and subsequent lung injury, and is therefore an injurious factor to the lung. Avoiding cellular stress failure is crucial to ventilator-induced lung injury (VILI treatment. In the present study, primary rat alveolar type II (ATII cells were isolated to evaluate their viability and the mechanism of their survival under tonic stretch. By the annexin V/ PI staining and flow cytometry assay, we demonstrated that tonic stretch-induced cell death is an immediate injury of mechanical stress. In addition, immunofluorescence and immunoblots assay showed that the cells experienced an expansion-contraction-reexpansion process, accompanied by partial focal adhesion (FA disassembly during contraction. Manipulation of integrin adherent affinity by altering bivalent cation levels in the culture medium and applying an integrin neutralizing antibody showed that facilitated adhesion affinity promoted cell death under tonic stretch, while lower level of adhesion protected the cells from stretch-induced stress failure. Finally, a simplified numerical model was established to reveal that adequate disassembly of FAs reduced the forces transmitting throughout the cell. Taken together, these results indicate that ATII cells escape stress failure caused by tonic stretch via active cell morphological remodeling, during which cells transiently disassemble FAs to unload mechanical forces.

  13. Periplasmic Acid Stress Increases Cell Division Asymmetry (Polar Aging of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Michelle W Clark

    Full Text Available Under certain kinds of cytoplasmic stress, Escherichia coli selectively reproduce by distributing the newer cytoplasmic components to new-pole cells while sequestering older, damaged components in cells inheriting the old pole. This phenomenon is termed polar aging or cell division asymmetry. It is unknown whether cell division asymmetry can arise from a periplasmic stress, such as the stress of extracellular acid, which is mediated by the periplasm. We tested the effect of periplasmic acid stress on growth and division of adherent single cells. We tracked individual cell lineages over five or more generations, using fluorescence microscopy with ratiometric pHluorin to measure cytoplasmic pH. Adherent colonies were perfused continually with LBK medium buffered at pH 6.00 or at pH 7.50; the external pH determines periplasmic pH. In each experiment, cell lineages were mapped to correlate division time, pole age and cell generation number. In colonies perfused at pH 6.0, the cells inheriting the oldest pole divided significantly more slowly than the cells inheriting the newest pole. In colonies perfused at pH 7.50 (near or above cytoplasmic pH, no significant cell division asymmetry was observed. Under both conditions (periplasmic pH 6.0 or pH 7.5 the cells maintained cytoplasmic pH values at 7.2-7.3. No evidence of cytoplasmic protein aggregation was seen. Thus, periplasmic acid stress leads to cell division asymmetry with minimal cytoplasmic stress.

  14. Cell Wall Invertase Promotes Fruit Set under Heat Stress by Suppressing ROS-Independent Cell Death.

    Science.gov (United States)

    Liu, Yong-Hua; Offler, Christina E; Ruan, Yong-Ling

    2016-09-01

    Reduced cell wall invertase (CWIN) activity has been shown to be associated with poor seed and fruit set under abiotic stress. Here, we examined whether genetically increasing native CWIN activity would sustain fruit set under long-term moderate heat stress (LMHS), an important factor limiting crop production, by using transgenic tomato (Solanum lycopersicum) with its CWIN inhibitor gene silenced and focusing on ovaries and fruits at 2 d before and after pollination, respectively. We found that the increase of CWIN activity suppressed LMHS-induced programmed cell death in fruits. Surprisingly, measurement of the contents of H2O2 and malondialdehyde and the activities of a cohort of antioxidant enzymes revealed that the CWIN-mediated inhibition on programmed cell death is exerted in a reactive oxygen species-independent manner. Elevation of CWIN activity sustained Suc import into fruits and increased activities of hexokinase and fructokinase in the ovaries in response to LMHS Compared to the wild type, the CWIN-elevated transgenic plants exhibited higher transcript levels of heat shock protein genes Hsp90 and Hsp100 in ovaries and HspII17.6 in fruits under LMHS, which corresponded to a lower transcript level of a negative auxin responsive factor IAA9 but a higher expression of the auxin biosynthesis gene ToFZY6 in fruits at 2 d after pollination. Collectively, the data indicate that CWIN enhances fruit set under LMHS through suppression of programmed cell death in a reactive oxygen species-independent manner that could involve enhanced Suc import and catabolism, HSP expression, and auxin response and biosynthesis. PMID:27462084

  15. The influence of chronic stress on T cell immunity

    OpenAIRE

    Sommershof, Annette

    2010-01-01

    Chronic environmental and psychological stress has long been suspected to increase the susceptibility and outcome of numerous infectious and inflammatory diseases. The release of neurotransmitters (catecholamines) and adrenal hormones (glucocorticoids) has been well documented as the basis for a connection between the central nervous system and peripheral components of the immune system. Glucocorticoids, the end products of stress-induced neuroendocrine pathways and the hypothalamic-pituitary...

  16. Theory to predict shear stress on cells in turbulent blood flow.

    Science.gov (United States)

    Morshed, Khandakar Niaz; Bark, David; Forleo, Marcio; Dasi, Lakshmi Prasad

    2014-01-01

    Shear stress on blood cells and platelets transported in a turbulent flow dictates the fate and biological activity of these cells. We present a theoretical link between energy dissipation in turbulent flows to the shear stress that cells experience and show that for the case of physiological turbulent blood flow: (a) the Newtonian assumption is valid, (b) turbulent eddies are universal for the most complex of blood flow problems, and (c) shear stress distribution on turbulent blood flows is possibly universal. Further we resolve a long standing inconsistency in hemolysis between laminar and turbulent flow using the theoretical framework. This work demonstrates that energy dissipation as opposed to bulk shear stress in laminar or turbulent blood flow dictates local mechanical environment of blood cells and platelets universally.

  17. Stem cell function and stress response are controlled by protein synthesis.

    Science.gov (United States)

    Blanco, Sandra; Bandiera, Roberto; Popis, Martyna; Hussain, Shobbir; Lombard, Patrick; Aleksic, Jelena; Sajini, Abdulrahim; Tanna, Hinal; Cortés-Garrido, Rosana; Gkatza, Nikoletta; Dietmann, Sabine; Frye, Michaela

    2016-06-16

    Whether protein synthesis and cellular stress response pathways interact to control stem cell function is currently unknown. Here we show that mouse skin stem cells synthesize less protein than their immediate progenitors in vivo, even when forced to proliferate. Our analyses reveal that activation of stress response pathways drives both a global reduction of protein synthesis and altered translational programmes that together promote stem cell functions and tumorigenesis. Mechanistically, we show that inhibition of post-transcriptional cytosine-5 methylation locks tumour-initiating cells in this distinct translational inhibition programme. Paradoxically, this inhibition renders stem cells hypersensitive to cytotoxic stress, as tumour regeneration after treatment with 5-fluorouracil is blocked. Thus, stem cells must revoke translation inhibition pathways to regenerate a tissue or tumour. PMID:27306184

  18. Stem cell function and stress response are controlled by protein synthesis.

    Science.gov (United States)

    Blanco, Sandra; Bandiera, Roberto; Popis, Martyna; Hussain, Shobbir; Lombard, Patrick; Aleksic, Jelena; Sajini, Abdulrahim; Tanna, Hinal; Cortés-Garrido, Rosana; Gkatza, Nikoletta; Dietmann, Sabine; Frye, Michaela

    2016-06-15

    Whether protein synthesis and cellular stress response pathways interact to control stem cell function is currently unknown. Here we show that mouse skin stem cells synthesize less protein than their immediate progenitors in vivo, even when forced to proliferate. Our analyses reveal that activation of stress response pathways drives both a global reduction of protein synthesis and altered translational programmes that together promote stem cell functions and tumorigenesis. Mechanistically, we show that inhibition of post-transcriptional cytosine-5 methylation locks tumour-initiating cells in this distinct translational inhibition programme. Paradoxically, this inhibition renders stem cells hypersensitive to cytotoxic stress, as tumour regeneration after treatment with 5-fluorouracil is blocked. Thus, stem cells must revoke translation inhibition pathways to regenerate a tissue or tumour.

  19. Adenomatous polyposis coli mutants dominantly activate Hsf1-dependent cell stress pathways through inhibition of microtubule dynamics

    OpenAIRE

    Davies, Alexander E.; Kortright, Kaitlyn; Kaplan, Kenneth B.

    2015-01-01

    Cancer cells up-regulate cell stress pathways, including the protein chaperone Hsp90. Increases in Hsp90 are believed “buffer” mutant protein activities necessary for cancer phenotypes. Activation of the cell stress pathway also alters the transcriptional landscape of cells in ways that are critical for cancer progression. However, it is unclear when and how the cell stress pathway is de-regulated during cancer progression. Here we report that mutations in adenomatous polyposis coli (APC) fou...

  20. Chronic stress induces ageing-associated degeneration in rat Leydig cells

    Institute of Scientific and Technical Information of China (English)

    Fei-Fei Wang; Qian Wang; Yong Chen; Qiang Lin; Hui-Bao Gao; Ping Zhang

    2012-01-01

    Several studies have suggested that stress and ageing exert inhibitory effects on rat Leydig cells.In a pattern similar to the normal process of Leydig cell ageing,stress-mediated increases in glucocorticoid levels inhibit steroidogenic enzyme expression that then results in decreased testosterone secretion.We hypothesized that chronic stress accelerates the degenerative changes associated with ageing in Leydig cells.To test this hypothesis,we established a model of chronic stress to evaluate stress-induced morphological and functional alterations in Brown Norway rat Leydig cells; additionally,intracellular lipofuscin levels,reactive oxygen species (ROS)levels and DNA damage were assessed.The results showed that chronic stress accelerated ageing-related changes:ultrastructural alterations associated with ageing,cellular lipofuscin accumulation,increased ROS levels and more extensive DNA damage were observed.Additionally,testosterone levels were decreased.This study sheds new light on the idea that chronic stress contributes to the degenerative changes associated with ageing in rat Leydig cells in vivo.

  1. Modulation of oxidative stress and subsequent induction of apoptosis and endoplasmic reticulum stress allows citral to decrease cancer cell proliferation.

    Science.gov (United States)

    Kapur, Arvinder; Felder, Mildred; Fass, Lucas; Kaur, Justanjot; Czarnecki, Austin; Rathi, Kavya; Zeng, San; Osowski, Kathryn Kalady; Howell, Colin; Xiong, May P; Whelan, Rebecca J; Patankar, Manish S

    2016-01-01

    The monoterpenoid, citral, when delivered through PEG-b-PCL nanoparticles inhibits in vivo growth of 4T1 breast tumors. Here, we show that citral inhibits proliferation of multiple human cancer cell lines. In p53 expressing ECC-1 and OVCAR-3 but not in p53-deficient SKOV-3 cells, citral induces G1/S cell cycle arrest and apoptosis as determined by Annexin V staining and increased cleaved caspase3 and Bax and decreased Bcl-2. In SKOV-3 cells, citral induces the ER stress markers CHOP, GADD45, EDEM, ATF4, Hsp90, ATG5, and phospho-eIF2α. The molecular chaperone 4-phenylbutyric acid attenuates citral activity in SKOV-3 but not in ECC-1 and OVCAR-3 cells. In p53-expressing cells, citral increases phosphorylation of serine-15 of p53. Activation of p53 increases Bax, PUMA, and NOXA expression. Inhibition of p53 by pifithrin-α, attenuates citral-mediated apoptosis. Citral increases intracellular oxygen radicals and this leads to activation of p53. Inhibition of glutathione synthesis by L-buthionine sulfoxamine increases potency of citral. Pretreatment with N-acetylcysteine decreases phosphorylation of p53 in citral-treated ECC-1 and OVCAR-3. These results define a p53-dependent, and in the absence of p53, ER stress-dependent mode of action of citral. This study indicates that citral in PEG-b-PCL nanoparticle formulation should be considered for treatment of breast and other tumors. PMID:27270209

  2. The mechanisms of up-regulation of dendritic cell activity by oxidative stress.

    Science.gov (United States)

    Batal, Ibrahim; Azzi, Jamil; Mounayar, Marwan; Abdoli, Rozita; Moore, Robert; Lee, Jack Y; Rosetti, Florencia; Wang, Chang; Fiorina, Paolo; Sackstein, Robert; Ichimura, Takaharu; Abdi, Reza

    2014-08-01

    Whereas DC have increasingly been recognized for their role in activating the inflammatory cascades during IRIs, the mechanisms by which oxidative stress enhances DC activation remain to be explored. We examined the role of oxidative stress on two important features of DC: T cell activation and trafficking. Bone marrow-derived OS-DC were compared with untreated DC. DC exposed to oxidative stress augmented allogeneic T cell proliferation and showed increased migration in a chemotaxis chamber. These results were confirmed by using hypoxanthine and xanthine oxidase as another inducer of oxidative stress. We used OT-II and OT-I mice to assess the effect of oxidative stress on DC activation of OVA-specific CD4(+) and CD8(+) T cells, respectively. Oxidative stress increased DC capacity to promote OVA-specific CD4(+) T cell activity, demonstrated by an increase in their proliferation and production of IFN-γ, IL-6, and IL-2 proinflammatory cytokines. Whereas oxidative stress increased the DC ability to stimulate IFN-γ production by OVA-specific CD8(+) T cells, cellular proliferation and cytotoxicity were not affected. Compared with untreated DC, oxidative stress significantly reduced the capacity of DC to generate T(regs), which were restored by using anti-IL-6. With regard to DC trafficking, whereas oxidative stress increased DC expression of p-Akt and p-NF-κB, targeting PI3Kγ and NF-κB pathways abrogated the observed increase in DC migration. Our data propose novel insights on the activation of DC by oxidative stress and provide rationales for targeted therapies, which can potentially attenuate IRI.

  3. Conception et calibration d'un sonoreacteur pour l'oxydation de la cellulose par le systeme TEMPO/NaOCl/NaBr

    Science.gov (United States)

    Paquin, Michel

    Avec le contexte economique actuel dans le domaine des pates et papiers au Canada, l'industrie se doit de diversifier ses produits mis en marche. La fermeture de plus de 20 usines depuis 2005, une baisse du PIB de l'industrie de 1,4 milliard CAD entre 1999--2008, une baisse de la demande de 2,4 %, une diminution du prix de la pate de 20,9 % depuis juillet 2009. La delocalisation du secteur vers l'Asie et l'hemisphere sud sont autant de raisons pour laquelle l'industrie se doit d'etre a l'avant plan de nouvelle technologie a base de fibre de bois. Pour augmenter leur rentabilite, l'industrie se doit de diversifier ses produits dans d'autres secteurs que le simple fabricant de papier impression-ecriture. Sa diversification passe par l'elaboration de nouveaux papiers a valeur ajoutee (papier conducteur, papier bioactif, etc.), par l'utilisation de la biomasse forestiere pour la production d'energie, par l'utilisation de la biomasse forestiere pour l'elaboration d'une plateforme de chimie verte, par l'utilisation de la lignine pour le developpement de polymeres et par l'utilisation de la fibre cellulosique pour la fabrication de nanomateriaux. La fabrication de nanofibrille de cellulose peut devenir un des produits qui servira a diversifier la production des usines de pates et papiers. Les nanofibrilles de cellulose possedent des proprietes mecaniques et chimiques exceptionnelles. Les nanofibrilles de cellulose sont fabriquees a partir d'une oxydation selective de la pate kraft de feuillu avec le systeme TEMPO-NaOCl-NaBr. L'oxydation selective de l'alcool primaire en C6 du monomere de glucose sous forme de carboxylates engendre une modification chimique de la cellulose qui accroit l'hydrophilicite des fibrilles. Suite a cette oxydation, nous devons effectuer une desintegration mecanique de la fibre kraft de feuillu oxydee pour separer les fibrilles. Le processus d'oxydation de la fibre par le systeme TEMPO-NaOCl-NaBr et sa defibrillation par la suite engendre une

  4. Influence of Water Stress on Endogenous Hormone Contents and Cell Damage of Maize Seedlings

    Institute of Scientific and Technical Information of China (English)

    Chunrong Wang; Aifang Yang; Haiying Yin; Juren Zhang

    2008-01-01

    Phytohormones play critical roles In regulating plant responses to stress. We Investigated the effects of water stress Induced by adding 12% (w/v) polyethylene glycol to the root medium on the levels of abscisic acid (ABA), indole-3-acid (IAA), zeatin (ZT), and gibberellin3 (GA3) in maize leaves. The results suggested that water stress had significant effects on the four hormone levels. There was a transient increase in the IAA content during the initial stage of adaptation to water stress in maize leaves, but it dropped sharply thereafter in response to water stress. ABA content increased dramatically in maize leaves after 24 h of exposure to water stress, and then the high levels of ABA were maintained to the end, The contents Of ZT and GA3 rapidly declined in maize leaves subjected to water stress. The effects of water stress on chlorophyll content, electrolyte leakage and malondialdehyde levels in maize leaves were also studied. The variation of cell damage was negatively correlated with ZT and GA3 levels in maize leaves under water stress. Thus, we explored the roles of ZT and GA3 on the growth of maize seedlings under water stress by exogenous application. It is possible that both ZT and GA3 were effective in protecting maize seedlings from water stress, which would be of great importance for the improvement of drought tolerance in maize by genetic manipulation.

  5. Cell mechanics and stress: from molecular details to the 'universal cell reaction' and hormesis.

    Science.gov (United States)

    Agutter, Paul S

    2007-04-01

    The 'universal cell reaction' (UCR), a coordinated biphasic response to external (noxious and other) stimuli observed in all living cells, was described by Nasonov and his colleagues in the mid-20th century. This work has received no attention from cell biologists in the West, but the UCR merits serious consideration. Although it is non-specific, it is likely to be underpinned by precise mechanisms and, if these mechanisms were characterized and their relationship to the UCR elucidated, then our understanding of the integration of cellular function could be improved. As a step towards identifying such mechanisms, I review some recent advances in understanding cell mechanics and the stress response and I suggest potentially testable hypotheses. There is a particular need for time-course studies of cellular responses to different stimulus doses or intensities. I also suggest a correspondence with hormesis; re-investigation of the UCR using modern biophysical and molecular-biological techniques might throw light on this much-discussed phenomenon.

  6. Androgen excess produces systemic oxidative stress and predisposes to beta-cell failure in female mice.

    Directory of Open Access Journals (Sweden)

    Suhuan Liu

    Full Text Available In women, excess production of the male hormone, testosterone (T, is accompanied by insulin resistance. However, hyperandrogenemia is also associated with beta-cell dysfunction and type 2 diabetes raising the possibility that androgen receptor (AR activation predisposes to beta-cell failure. Here, we tested the hypothesis that excess AR activation produces systemic oxidative stress thereby contributing to beta-cell failure. We used normal female mice (CF and mice with androgen resistance by testicular feminization (Tfm. These mice were exposed to androgen excess and a beta-cell stress induced by streptozotocin (STZ. We find that following exposure to T, or the selective AR-agonist dehydrotestosterone (DHT, CF mice challenged with STZ, which are normally protected, are prone to beta-cell failure and insulin-deficient diabetes. Conversely, T-induced predisposition to beta-cell failure is abolished in Tfm mice. We do not observe any proapoptotic effect of DHT alone or in the presence of H(2O(2 in cultured mouse and human islets. However, we observe that exposure of CF mice to T or DHT provokes systemic oxidative stress, which is eliminated in Tfm mice. This work has significance for hyperandrogenic women; excess activation of AR by testosterone may provoke systemic oxidative stress. In the presence of a prior beta-cell stress, this may predispose to beta-cell failure.

  7. Naphthoquinone Derivative PPE8 Induces Endoplasmic Reticulum Stress in p53 Null H1299 Cells

    Directory of Open Access Journals (Sweden)

    Jin-Cherng Lien

    2015-01-01

    Full Text Available Endoplasmic reticulum (ER plays a key role in synthesizing secretory proteins and sensing signal function in eukaryotic cells. Responding to calcium disturbance, oxidation state change, or pharmacological agents, ER transmembrane protein, inositol-regulating enzyme 1 (IRE1, senses the stress and triggers downstream signals. Glucose-regulated protein 78 (GRP78 dissociates from IRE1 to assist protein folding and guard against cell death. In prolonged ER stress, IRE1 recruits and activates apoptosis signal-regulating kinase 1 (ASK1 as well as downstream JNK for cell death. Naphthoquinones are widespread natural phenolic compounds. Vitamin K3, a derivative of naphthoquinone, inhibits variant tumor cell growth via oxygen uptake and oxygen stress. We synthesized a novel naphthoquinone derivative PPE8 and evaluated capacity to induce ER stress in p53 null H1299 and p53 wild-type A549 cells. In H1299 cells, PPE8 induced ER enlargement, GRP78 expression, and transient IER1 activation. Activated IRE1 recruited ASK1 for downstream JNK phosphorylation. IRE1 knockdown by siRNA attenuated PPE8-induced JNK phosphorylation and cytotoxicity. Prolonged JNK phosphorylation may be involved in PPE8-induced cytotoxicity. Such results did not arise in A549 cells, but p53 knockdown by siRNA restored PPE8-induced GRP78 expression and JNK phosphorylation. We offer a novel compound to induce ER stress and cytotoxicity in p53-deficient cancer cells, presenting an opportunity for treatment.

  8. Romo1 expression contributes to oxidative stress-induced death of lung epithelial cells

    International Nuclear Information System (INIS)

    Highlights: •Romo1 mediates oxidative stress-induced mitochondrial ROS production. •Romo1 induction by oxidative stress plays an important role in oxidative stress-induced apoptosis. •Romo1 overexpression correlates with epithelial cell death in patients with IPF. -- Abstract: Oxidant-mediated death of lung epithelial cells due to cigarette smoking plays an important role in pathogenesis in lung diseases such as idiopathic pulmonary fibrosis (IPF). However, the exact mechanism by which oxidants induce epithelial cell death is not fully understood. Reactive oxygen species (ROS) modulator 1 (Romo1) is localized in the mitochondria and mediates mitochondrial ROS production through complex III of the mitochondrial electron transport chain. Here, we show that Romo1 mediates mitochondrial ROS production and apoptosis induced by oxidative stress in lung epithelial cells. Hydrogen peroxide (H2O2) treatment increased Romo1 expression, and Romo1 knockdown suppressed the cellular ROS levels and cell death triggered by H2O2 treatment. In immunohistochemical staining of lung tissues from patients with IPF, Romo1 was mainly localized in hyperplastic alveolar and bronchial epithelial cells. Romo1 overexpression was detected in 14 of 18 patients with IPF. TUNEL-positive alveolar epithelial cells were also detected in most patients with IPF but not in normal controls. These findings suggest that Romo1 mediates apoptosis induced by oxidative stress in lung epithelial cells

  9. Romo1 expression contributes to oxidative stress-induced death of lung epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Jung Ar [Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul 135-270 (Korea, Republic of); Chung, Jin Sil [Laboratory of Molecular Cell Biology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713 (Korea, Republic of); Cho, Sang-Ho [Department of Pathology, Pochon CHA University, College of Medicine, Gyeonggi-do (Korea, Republic of); Kim, Hyung Jung, E-mail: khj57@yuhs.ac.kr [Department of Internal Medicine, Yonsei University College of Medicine, Yonsei University Health System, Seoul 135-270 (Korea, Republic of); Yoo, Young Do, E-mail: ydy1130@korea.ac.kr [Laboratory of Molecular Cell Biology, College of Life Sciences and Biotechnology, Korea University, Seoul 136-713 (Korea, Republic of)

    2013-09-20

    Highlights: •Romo1 mediates oxidative stress-induced mitochondrial ROS production. •Romo1 induction by oxidative stress plays an important role in oxidative stress-induced apoptosis. •Romo1 overexpression correlates with epithelial cell death in patients with IPF. -- Abstract: Oxidant-mediated death of lung epithelial cells due to cigarette smoking plays an important role in pathogenesis in lung diseases such as idiopathic pulmonary fibrosis (IPF). However, the exact mechanism by which oxidants induce epithelial cell death is not fully understood. Reactive oxygen species (ROS) modulator 1 (Romo1) is localized in the mitochondria and mediates mitochondrial ROS production through complex III of the mitochondrial electron transport chain. Here, we show that Romo1 mediates mitochondrial ROS production and apoptosis induced by oxidative stress in lung epithelial cells. Hydrogen peroxide (H{sub 2}O{sub 2}) treatment increased Romo1 expression, and Romo1 knockdown suppressed the cellular ROS levels and cell death triggered by H{sub 2}O{sub 2} treatment. In immunohistochemical staining of lung tissues from patients with IPF, Romo1 was mainly localized in hyperplastic alveolar and bronchial epithelial cells. Romo1 overexpression was detected in 14 of 18 patients with IPF. TUNEL-positive alveolar epithelial cells were also detected in most patients with IPF but not in normal controls. These findings suggest that Romo1 mediates apoptosis induced by oxidative stress in lung epithelial cells.

  10. Cell division plane orientation based on tensile stress in Arabidopsis thaliana.

    Science.gov (United States)

    Louveaux, Marion; Julien, Jean-Daniel; Mirabet, Vincent; Boudaoud, Arezki; Hamant, Olivier

    2016-07-26

    Cell geometry has long been proposed to play a key role in the orientation of symmetric cell division planes. In particular, the recently proposed Besson-Dumais rule generalizes Errera's rule and predicts that cells divide along one of the local minima of plane area. However, this rule has been tested only on tissues with rather local spherical shape and homogeneous growth. Here, we tested the application of the Besson-Dumais rule to the divisions occurring in the Arabidopsis shoot apex, which contains domains with anisotropic curvature and differential growth. We found that the Besson-Dumais rule works well in the central part of the apex, but fails to account for cell division planes in the saddle-shaped boundary region. Because curvature anisotropy and differential growth prescribe directional tensile stress in that region, we tested the putative contribution of anisotropic stress fields to cell division plane orientation at the shoot apex. To do so, we compared two division rules: geometrical (new plane along the shortest path) and mechanical (new plane along maximal tension). The mechanical division rule reproduced the enrichment of long planes observed in the boundary region. Experimental perturbation of mechanical stress pattern further supported a contribution of anisotropic tensile stress in division plane orientation. Importantly, simulations of tissues growing in an isotropic stress field, and dividing along maximal tension, provided division plane distributions comparable to those obtained with the geometrical rule. We thus propose that division plane orientation by tensile stress offers a general rule for symmetric cell division in plants.

  11. Stress

    DEFF Research Database (Denmark)

    Keller, Hanne Dauer

    2015-01-01

    Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb.......Kapitlet handler om stress som følelse, og det trækker primært på de få kvalitative undersøgelser, der er lavet af stressforløb....

  12. RIPK1 regulates survival of human melanoma cells upon endoplasmic reticulum stress through autophagy.

    Science.gov (United States)

    Luan, Qi; Jin, Lei; Jiang, Chen Chen; Tay, Kwang Hong; Lai, Fritz; Liu, Xiao Ying; Liu, Yi Lun; Guo, Su Tang; Li, Chun Ying; Yan, Xu Guang; Tseng, Hsin-Yi; Zhang, Xu Dong

    2015-01-01

    Although RIPK1 (receptor [TNFRSF]-interacting protein kinase 1) is emerging as a critical determinant of cell fate in response to cellular stress resulting from activation of death receptors and DNA damage, its potential role in cell response to endoplasmic reticulum (ER) stress remains undefined. Here we report that RIPK1 functions as an important prosurvival mechanism in melanoma cells undergoing pharmacological ER stress induced by tunicamycin (TM) or thapsigargin (TG) through activation of autophagy. While treatment with TM or TG upregulated RIPK1 and triggered autophagy in melanoma cells, knockdown of RIPK1 inhibited autophagy and rendered the cells sensitive to killing by TM or TG, recapitulating the effect of inhibition of autophagy. Consistently, overexpression of RIPK1 enhanced induction of autophagy and conferred resistance of melanoma cells to TM- or TG-induced cell death. Activation of MAPK8/JNK1 or MAPK9/JNK2, which phosphorylated BCL2L11/BIM leading to its dissociation from BECN1/Beclin 1, was involved in TM- or TG-induced, RIPK1-mediated activation of autophagy; whereas, activation of the transcription factor HSF1 (heat shock factor protein 1) downstream of the ERN1/IRE1-XBP1 axis of the unfolded protein response was responsible for the increase in RIPK1 in melanoma cells undergoing pharmacological ER stress. Collectively, these results identify upregulation of RIPK1 as an important resistance mechanism of melanoma cells to TM- or TG-induced ER stress by protecting against cell death through activation of autophagy, and suggest that targeting the autophagy-activating mechanism of RIPK1 may be a useful strategy to enhance sensitivity of melanoma cells to therapeutic agents that induce ER stress.

  13. Salidroside Suppresses HUVECs Cell Injury Induced by Oxidative Stress through Activating the Nrf2 Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Yao Zhu

    2016-08-01

    Full Text Available Oxidative stress plays an important role in the pathogenesis of cardiovascular diseases. Salidroside (SAL, one of the main effective constituents of Rhodiola rosea, has been reported to suppress oxidative stress-induced cardiomyocyte injury and necrosis by promoting transcription of nuclear factor E2-related factor 2 (Nrf2-regulated genes such as heme oxygenase-1 (HO-1 and NAD(PH dehydrogenase (quinone1 (NQO1. However, it has not been indicated whether SAL might ameliorate endothelial injury induced by oxidative stress. Here, our study demonstrated that SAL might suppress HUVEC cell injury induced by oxidative stress through activating the Nrf2 signaling pathway. The results of our study indicated that SAL decreased the levels of intercellular reactive oxygen species (ROS and malondialdehyde (MDA, and improved the activities of superoxide dismutase (SOD and catalase (CAT, resulting in protective effects against oxidative stress-induced cell damage in HUVECs. It suppressed oxidative stress damage by inducing Nrf2 nuclear translocation and activating the expression of Nrf2-regulated antioxidant enzyme genes such as HO-1 and NQO1 in HUVECs. Knockdown of Nrf2 with siRNA abolished the cytoprotective effects against oxidative stress, decreased the expression of Nrf2, HO-1, and NQO1, and inhibited the nucleus translocation of Nrf2 in HUVECs. This study is the first to demonstrate that SAL suppresses HUVECs cell injury induced by oxidative stress through activating the Nrf2 signaling pathway.

  14. Advanced glycation end products inhibit testosterone secretion by rat Leydig cells by inducing oxidative stress and endoplasmic reticulum stress.

    Science.gov (United States)

    Zhao, Yun-Tao; Qi, Ya-Wei; Hu, Chuan-Yin; Chen, Shao-Hong; Liu, You

    2016-08-01

    Diabetes severely impairs male reproduction. The present study assessed the effects and mechanisms of action of advanced glycation end products (AGEs), which play an important role in the development of diabetes complications, on testosterone secretion by rat Leydig cells. Primary rat Leydig cells were cultured and treated with AGEs (25, 50, 100 and 200 µg/ml). Testosterone production induced by human chorionic gonadotropin (hCG) was determined by ELISA. The mRNA and protein expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side-chain cleavage enzyme (P450scc) and 3β-hydroxysteroid dehydrogenase (3β-HSD), which are involved in testosterone biosynthesis, were measured by reverse transcription-quantitative PCR and western blot analyssi, respectively. Reactive oxygen species (ROS) production in Leydig cells was measured using the dichlorofluorescein diacetate (DCFH-DA) probe. The expression levels of endoplasmic reticulum stress-related proteins [C/EBP homologous protein (CHOP) and glucose-regulated protein 78 (GRP78)] in the Leydig cells were measured by western blot analysis. We found that the AGEs markedly suppressed testosterone production by rat Leydig cells which was induced by hCG in a concentration-dependent manner compared with the control (PStAR, 3β-HSD and P450scc were downregulated by the AGEs in a dose-dependent manner compared with the control (P<0.01). The antioxidant agent, N-acetyl‑L‑cysteine (NAC), and the endoplasmic reticulum stress inhibitor, tauroursodeoxycholic acid (TUDCA), reversed the inhibitory effects of AGEs. In addition, the content of ROS in Leydig cells treated with AGEs increased significantly. The expression levels of CHOP and GRP78 were markedly upregulated by the AGEs in the Leydig cells. From these findings, it can be concluded that AGEs inhibit testosterone production by rat Leydig cells by inducing oxidative stress and endoplasmic reticulum stress. PMID:27315604

  15. Hsp70 as an indicator of stress in the cells after contact with nanoparticles

    Science.gov (United States)

    Hardilová, Šárka; Havrdová, Markéta; Panáček, Aleš; Kvítek, Libor; Zbořil, Radek

    2015-05-01

    In recent years, production of nanoparticles is increased and thus grows our contact with them too. Question of safety is closely related to the issue of use nanoparticles. There are a number of tests that monitor the viability, ROS production, the effect on the DNA and cell cycle, however, rarely encountered studies on stress in the cells after contact with nanoparticles. Heat shock proteins (HSP) are among the substances that can be used for monitoring stress in cells. HSP are structures with a chaperone activity. They are evolutionarily very old, conservative and they are found with a high degree of homology in prokaryotes and eukaryotes including humans. They exist at low concentrations under physiological conditions, while in the denaturing conditions e.g. high or low temperature, radiation, exposure to chemicals, heavy metals, or nanoparticles their expression is changed. HSPs are involved in maintaining homeostasis in the cell that the denatured protein conformations allow recovery to the original stage. One of the most common proteins from HSP family is Hsp70 - protein with a molecular weight of 70 kDa. The level of Hsp70 in a cell after exposure to the stress changes depending on the stress level to which the cell is exposed to and a time period during which lasted stressful conditions. Our research monitors stress levels of cells manifesting by Hsp70 production after contact with silver nanoparticles. Nanoparticles show different toxicity towards different types of target cells, which is reflected in the values of IC50 - concentration that kills 50% tested cells. Concentration of test substance toxic to one cell type may be innocuous to cells of another type. IC50 obtained from the MTT assay provides a suitable default data and if multiples of IC50 values are used, we can compare and generalize. Studies can be used to compare stress levels in cells that show different sensitivity to the tested nanoparticles compared with cells under optimal growth

  16. Downregulation of miR-205 modulates cell susceptibility to oxidative and endoplasmic reticulum stresses in renal tubular cells.

    Directory of Open Access Journals (Sweden)

    Shiyo Muratsu-Ikeda

    Full Text Available BACKGROUND: Oxidative stress and endoplasmic reticulum (ER stress play a crucial role in tubular damage in both acute kidney injury (AKI and chronic kidney disease (CKD. While the pathophysiological contribution of microRNAs (miRNA to renal damage has also been highlighted, the effect of miRNA on renal damage under oxidative and ER stresses conditions remains elusive. METHODS: We assessed changes in miRNA expression in the cultured renal tubular cell line HK-2 under hypoxia-reoxygenation-induced oxidative stress or ER stress using miRNA microarray assay and real-time RT-PCR. The pathophysiological effect of miRNA was evaluated by cell survival rate, intracellular reactive oxygen species (ROS level, and anti-oxidant enzyme expression in miRNA-inhibited HK-2 or miRNA-overexpressed HK-2 under these stress conditions. The target gene of miRNA was identified by 3'-UTR-luciferase assay. RESULTS: We identified 8 and 10 miRNAs whose expression was significantly altered by oxidative and ER stresses, respectively. Among these, expression of miR-205 was markedly decreased in both stress conditions. Functional analysis revealed that decreased miR-205 led to an increase in cell susceptibility to oxidative and ER stresses, and that this increase was associated with the induction of intracellular ROS and suppression of anti-oxidant enzymes. While increased miR-205 by itself made no change in cell growth or morphology, cell viability under oxidative or ER stress conditions was partially restored. Further, miR-205 bound to the 3'-UTR of the prolyl hydroxylase 1 (PHD1/EGLN2 gene and suppressed the transcription level of EGLN2, which modulates both intracellular ROS level and ER stress state. CONCLUSIONS: miR-205 serves a protective role against both oxidative and ER stresses via the suppression of EGLN2 and subsequent decrease in intracellular ROS. miR-205 may represent a novel therapeutic target in AKI and CKD associated with oxidative or ER stress in tubules.

  17. Structure of xanthan gum and cell ultrastructure at different times of alkali stress

    Science.gov (United States)

    de Mello Luvielmo, Márcia; Borges, Caroline Dellinghausen; de Oliveira Toyama, Daniela; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24 h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  18. Structure of xanthan gum and cell ultrastructure at different times of alkali stress.

    Science.gov (United States)

    Luvielmo, Márcia de Mello; Borges, Caroline Dellinghausen; Toyama, Daniela de Oliveira; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

    2016-01-01

    The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. PMID:26887232

  19. Using a co-culture microsystem for cell migration under fluid shear stress.

    Science.gov (United States)

    Yeh, Chia-Hsien; Tsai, Shen-Hsing; Wu, Li-Wha; Lin, Yu-Cheng

    2011-08-01

    We have successfully developed a microsystem to co-cultivate two types of cells with a minimum defined gap of 50 μm, and to quantitatively study the impact of fluid shear stress on the mutual influence of cell migration velocity and distance. We used the hydrostatic pressure to seed two different cells, endothelial cells (ECs) and smooth muscle cells (SMCs), on opposite sides of various gap sizes (500 μm, 200 μm, 100 μm, and 50 μm). After cultivating the cells for 12 h and peeling the co-culture microchip from the culture dish, we studied the impacts of gap size on the migration of either cell type in the absence or presence of fluid shear stress (7 dyne cm(-2) and 12 dyne cm(-2)) influence. We found that both gap size and shear stress have profound influence on cell migration. Smaller gap sizes (100 μm and 50 μm) significantly enhanced cell migration, suggesting a requirement of an effective concentration of released factor(s) by either cell type in the gap region. Flow-induced shear stress delayed the migration onset of either cell type in a dose-dependent manner regardless of the gap size. Moreover, shear stress-induced decrease of cell migration becomes evident when the gap size was 500 μm. We have developed a co-culture microsystem for two kinds of cells and overcome the conventional difficulties in observation and mixed culture, and it would have more application for bio-manipulation and tissue repair engineering.

  20. The cell wall and endoplasmic reticulum stress responses are coordinately regulated in Saccharomyces cerevisiae

    OpenAIRE

    Krysan, Damian J.

    2009-01-01

    The unfolded protein response (UPR) is an intracellular signaling pathway that regulates the cellular response to the accumulation of misfolded proteins in eukaryotes. Our group has demonstrated that cell wall stress activates UPR in yeast through signals transmitted by the cell wall integrity (CWI) mitogen-activated protein (MAP) kinase cascade. The UPR is required to maintain cell wall integrity; mutants lacking a functional UPR have defects in cell wall biosynthesis and are hypersensitive ...

  1. On-Chip Quantitative Measurement of Mechanical Stresses During Cell Migration with Emulsion Droplets

    OpenAIRE

    Molino, D.; S. Quignard; Gruget, C.; Pincet, F.; Y. Chen; Piel, M.; Fattaccioli, J.

    2016-01-01

    The ability of immune cells to migrate within narrow and crowded spaces is a critical feature involved in various physiological processes from immune response to metastasis. Several in-vitro techniques have been developed so far to study the behaviour of migrating cells, the most recent being based on the fabrication of microchannels within which cells move. To address the question of the mechanical stress a cell is able to produce during the encounter of an obstacle while migrating, we devel...

  2. Membrane regulation of the stress response from prokaryotic models to mammalian cells.

    Science.gov (United States)

    Vigh, Laszlo; Nakamoto, Hitoshi; Landry, Jacques; Gomez-Munoz, Antonio; Harwood, John L; Horvath, Ibolya

    2007-10-01

    "Membrane regulation" of stress responses in various systems is widely studied. In poikilotherms, membrane rigidification could be the first reaction to cold perception: reducing membrane fluidity of membranes at physiological temperatures is coupled with enhanced cold inducibility of a number of genes, including desaturases (see J.L. Harwood's article in this Proceedings volume). A similar role of changes in membrane physical state in heat (oxidative stress, etc.) sensing- and signaling gained support recently from prokaryotes to mammalian cells. Stress-induced remodeling of membrane lipids could influence generation, transduction, and deactivation of stress signals, either through global effects on the fluidity of the membrane matrix, or by specific interactions of boundary (or raft) lipids with receptor proteins, lipases, ion channels, etc. Our data point to membranes not only as targets of stress, but also as sensors in activating a stress response. PMID:17656573

  3. Single cell mechanics: stress stiffening and kinematic hardening

    CERN Document Server

    Fernández, Pablo

    2007-01-01

    Cell mechanical properties are fundamental to the organism but remain poorly understood. We report a comprehensive phenomenological framework for the nonlinear rheology of single fibroblast cells: a superposition of elastic stiffening and viscoplastic kinematic hardening. Our results show, that in spite of cell complexity its mechanical properties can be cast into simple, well-defined rules, which provide mechanical cell strength and robustness via control of crosslink slippage.

  4. Single cell mechanics: stress stiffening and kinematic hardening.

    Science.gov (United States)

    Fernández, Pablo; Ott, Albrecht

    2008-06-13

    Cell mechanical properties are fundamental to the organism but remain poorly understood. We report a comprehensive phenomenological framework for the complex rheology of single fibroblast cells: a superposition of elastic stiffening and viscoplastic kinematic hardening. Despite the complexity of the living cell, its mechanical properties can be cast into simple, well-defined rules. Our results reveal the key role of crosslink slippage in determining mechanical cell strength and robustness. PMID:18643547

  5. Mechanical stress downregulates MHC class I expression on human cancer cell membrane.

    Directory of Open Access Journals (Sweden)

    Rosanna La Rocca

    Full Text Available In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal, depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700-1800 cm(-1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK cells cytotoxic recognition.

  6. Mechanical stress downregulates MHC class I expression on human cancer cell membrane.

    Science.gov (United States)

    La Rocca, Rosanna; Tallerico, Rossana; Talib Hassan, Almosawy; Das, Gobind; Lakshmikanth, Tadepally; Tadepally, Lakshmikanth; Matteucci, Marco; Liberale, Carlo; Mesuraca, Maria; Scumaci, Domenica; Gentile, Francesco; Cojoc, Gheorghe; Perozziello, Gerardo; Ammendolia, Antonio; Gallo, Adriana; Kärre, Klas; Cuda, Giovanni; Candeloro, Patrizio; Di Fabrizio, Enzo; Carbone, Ennio

    2014-01-01

    In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells) was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal), depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700-1800 cm(-1), indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK) cells cytotoxic recognition.

  7. Mechanical Stress Downregulates MHC Class I Expression on Human Cancer Cell Membrane

    KAUST Repository

    La Rocca, Rosanna

    2014-12-26

    In our body, cells are continuously exposed to physical forces that can regulate different cell functions such as cell proliferation, differentiation and death. In this work, we employed two different strategies to mechanically stress cancer cells. The cancer and healthy cell populations were treated either with mechanical stress delivered by a micropump (fabricated by deep X-ray nanolithography) or by ultrasound wave stimuli. A specific down-regulation of Major Histocompatibility Complex (MHC) class I molecules expression on cancer cell membrane compared to different kinds of healthy cells (fibroblasts, macrophages, dendritic and lymphocyte cells) was observed, stimulating the cells with forces in the range of nano-newton, and pressures between 1 and 10 bar (1 bar = 100.000 Pascal), depending on the devices used. Moreover, Raman spectroscopy analysis, after mechanical treatment, in the range between 700–1800 cm−1, indicated a relative concentration variation of MHC class I. PCA analysis was also performed to distinguish control and stressed cells within different cell lines. These mechanical induced phenotypic changes increase the tumor immunogenicity, as revealed by the related increased susceptibility to Natural Killer (NK) cells cytotoxic recognition.

  8. Toxicity and oxidative stress of canine mesenchymal stromal cells from adipose tissue in different culture passages

    Directory of Open Access Journals (Sweden)

    Arícia Gomes Sprada

    2015-12-01

    Full Text Available Abstract: Stem cells in regenerative therapy have received attention from researchers in recent decades. The culture of these cells allows studies about their behavior and metabolism. Thus, cell culture is the basis for cell therapy and tissue engineering researches. A major concern regarding the use of cultivated stem cell in human or veterinary clinical routine is the risk of carcinogenesis. Cellular activities require a balanced redox state. However, when there is an imbalance in this state, oxidative stress occurs. Oxidative stress contributes to cytotoxicity, which may result in cell death or genomic alterations, favoring the development of cancer cells. The aim of this study was to determine whether there are differences in the behavior of cultured mesenchymal stem cells from canine adipose tissue according to its site of collection (omentum and subcutaneous evaluating the rate of proliferation, viability, level of oxidative stress and cytotoxicity over six passages. For this experiment, two samples of adipose tissue from subcutaneous and omentum where taken from a female dog corpse, 13 years old, Pitbull. The results showed greater levels of oxidative stress in the first and last passages of both groups, favoring cytotoxicity and cell death.

  9. Accelerated fat cell aging links oxidative stress and insulin resistance in adipocytes

    Indian Academy of Sciences (India)

    Finny Monickaraj; Sankaramoorthy Aravind; Pichamoorthy Nandhini; Paramasivam Prabu; Chandrakumar Sathishkumar; Viswanathan Mohan; Muthuswamy Balasubramanyam

    2013-03-01

    Telomere shortening is emerging as a biological indicator of accelerated aging and aging-related diseases including type 2 diabetes. While telomere length measurements were largely done in white blood cells, there is lack of studies on telomere length in relation to oxidative stress in target tissues affected in diabetes. Therefore, the aim of this study is to induct oxidative stress in adipocytes and to test whether these adipocytes exhibit shortened telomeres, senescence and functional impairment. 3T3-L1 adipocytes were subjected to oxidative stress and senescence induction by a variety of means for 2 weeks (exogenous application of H2O2, glucose oxidase, asymmetric dimethylarginine (ADMA) and glucose oscillations). Cells were probed for reactive oxygen species generation (ROS), DNA damage, mRNA and protein expression of senescent and pro-inflammatory markers, telomere length and glucose uptake. Compared to untreated cells, both ROS generation and DNA damage were significantly higher in cells subjected to oxidative stress and senescence. Adipocytes subjected to oxidative stress also showed shortened telomeres and increased mRNA and protein expression of p53, p21, TNF and IL-6. Senescent cells were also characterized by decreased levels of adiponectin and impaired glucose uptake. Briefly, adipocytes under oxidative stress exhibited increased ROS generation, DNA damage, shortened telomeres and switched to senescent/pro-inflammatory phenotype with impaired glucose uptake.

  10. Angiogenin Mediates Cell-Autonomous Translational Control under Endoplasmic Reticulum Stress and Attenuates Kidney Injury.

    Science.gov (United States)

    Mami, Iadh; Bouvier, Nicolas; El Karoui, Khalil; Gallazzini, Morgan; Rabant, Marion; Laurent-Puig, Pierre; Li, Shuping; Tharaux, Pierre-Louis; Beaune, Philippe; Thervet, Eric; Chevet, Eric; Hu, Guo-Fu; Pallet, Nicolas

    2016-03-01

    Endoplasmic reticulum (ER) stress is involved in the pathophysiology of kidney disease and aging, but the molecular bases underlying the biologic outcomes on the evolution of renal disease remain mostly unknown. Angiogenin (ANG) is a ribonuclease that promotes cellular adaptation under stress but its contribution to ER stress signaling remains elusive. In this study, we investigated the ANG-mediated contribution to the signaling and biologic outcomes of ER stress in kidney injury. ANG expression was significantly higher in samples from injured human kidneys than in samples from normal human kidneys, and in mouse and rat kidneys, ANG expression was specifically induced under ER stress. In human renal epithelial cells, ER stress induced ANG expression in a manner dependent on the activity of transcription factor XBP1, and ANG promoted cellular adaptation to ER stress through induction of stress granules and inhibition of translation. Moreover, the severity of renal lesions induced by ER stress was dramatically greater in ANG knockout mice (Ang(-/-)) mice than in wild-type mice. These results indicate that ANG is a critical mediator of tissue adaptation to kidney injury and reveal a physiologically relevant ER stress-mediated adaptive translational control mechanism.

  11. The transcription factor NFAT5 is required for cyclin expression and cell cycle progression in cells exposed to hypertonic stress.

    Directory of Open Access Journals (Sweden)

    Katherine Drews-Elger

    Full Text Available BACKGROUND: Hypertonicity can perturb cellular functions, induce DNA damage-like responses and inhibit proliferation. The transcription factor NFAT5 induces osmoprotective gene products that allow cells to adapt to sustained hypertonic conditions. Although it is known that NFAT5-deficient lymphocytes and renal medullary cells have reduced proliferative capacity and viability under hypertonic stress, less is understood about the contribution of this factor to DNA damage responses and cell cycle regulation. METHODOLOGY/PRINCIPAL FINDINGS: We have generated conditional knockout mice to obtain NFAT5(-/- T lymphocytes, which we used as a model of proliferating cells to study NFAT5-dependent responses. We show that hypertonicity triggered an early, NFAT5-independent, genotoxic stress-like response with induction of p53, p21 and GADD45, downregulation of cyclins, and cell cycle arrest. This was followed by an NFAT5-dependent adaptive phase in wild-type cells, which induced an osmoprotective gene expression program, downregulated stress markers, resumed cyclin expression and proliferation, and displayed enhanced NFAT5 transcriptional activity in S and G2/M. In contrast, NFAT5(-/- cells failed to induce osmoprotective genes and exhibited poorer viability. Although surviving NFAT5(-/- cells downregulated genotoxic stress markers, they underwent cell cycle arrest in G1/S and G2/M, which was associated with reduced expression of cyclins E1, A2 and B1. We also show that pathologic hypertonicity levels, as occurring in plasma of patients and animal models of osmoregulatory disorders, inhibited the induction of cyclins and aurora B kinase in response to T cell receptor stimulation in fresh NFAT5(-/- lymphocytes. CONCLUSIONS/SIGNIFICANCE: We conclude that NFAT5 facilitates cell proliferation under hypertonic conditions by inducing an osmoadaptive response that enables cells to express fundamental regulators needed for cell cycle progression.

  12. Osmotic stress affects functional properties of human melanoma cell lines

    CERN Document Server

    La Porta, Caterina A M; Pasini, Maria; Laurson, Lasse; Alava, Mikko J; Zapperi, Stefano; Amar, Martine Ben

    2015-01-01

    Understanding the role of microenvironment in cancer growth and metastasis is a key issue for cancer research. Here, we study the effect of osmotic pressure on the functional properties of primary and metastatic melanoma cell lines. In particular, we experimentally quantify individual cell motility and transmigration capability. We then perform a circular scratch assay to study how a cancer cell front invades an empty space. Our results show that primary melanoma cells are sensitive to a low osmotic pressure, while metastatic cells are less. To better understand the experimental results, we introduce and study a continuous model for the dynamics of a cell layer and a stochastic discrete model for cell proliferation and diffusion. The two models capture essential features of the experimental results and allow to make predictions for a wide range of experimentally measurable parameters.

  13. Stress factor – dependent differences in molecular mechanisms of premature cell senescence

    Directory of Open Access Journals (Sweden)

    Petrova N. V.

    2015-10-01

    Full Text Available Cell senescence is an established cell stress response in the form of a permanent proliferation arrest accompanied by a complex phenotype. Senescent cells share several crucial features, such as lack of DNA synthesis, increased senescence-associated β-galactosidase activity and upregulation of cyclin-dependent kinase inhibitors. Most of these universal senescence markers are indicative not only for cell senescence but for other types of growth arrest as well. Along with ubiquitous markers, cell senescence has accessory characteristics, which mostly depend on senescence-inducing stimulus and/or cell type. Here, we review main markers and mechanisms involved in the induction of cell senescence with a focus on stress factor-dependent differences in signaling pathways activated in senescence.

  14. Diffusible Factors Secreted by Glioblastoma and Medulloblastoma Cells Induce Oxidative Stress in Bystander Neural Stem Progenitors.

    Science.gov (United States)

    Sharma, Neha; Colangelo, Nicholas W; de Toledo, Sonia M; Azzam, Edouard I

    2016-08-01

    Harmful effects that alter the homeostasis of neural stem or progenitor cells (NSPs) can affect regenerative processes in the central nervous system. We investigated the effect of soluble factors secreted by control or (137)Cs-γ-irradiated glioblastoma or medulloblastoma cells on redox-modulated endpoints in recipient human NSPs. Growth medium harvested from the nonirradiated brain tumor cells, following 24 h of growth, induced prominent oxidative stress in recipient NSPs as judged by overall increases in mitochondrial superoxide radical levels (p medulloblastoma cells that was more potent at inducing apoptosis in the NSPs than medium from nonirradiated cells (p < .001). The elucidation of such stressful bystander effects provides avenues to understand the biochemical events underlying the development or exacerbation of degenerative outcomes associated with brain cancers. It is also relevant to tissue culture protocols whereby growth medium conditioned by tumor cells is often used to support the growth of stem cells. PMID:27511909

  15. ATM regulation of IL-8 links oxidative stress to cancer cell migration and invasion.

    Science.gov (United States)

    Chen, Wei-Ta; Ebelt, Nancy D; Stracker, Travis H; Xhemalce, Blerta; Van Den Berg, Carla L; Miller, Kyle M

    2015-06-01

    Ataxia-telangiectasia mutated (ATM) protein kinase regulates the DNA damage response (DDR) and is associated with cancer suppression. Here we report a cancer-promoting role for ATM. ATM depletion in metastatic cancer cells reduced cell migration and invasion. Transcription analyses identified a gene network, including the chemokine IL-8, regulated by ATM. IL-8 expression required ATM and was regulated by oxidative stress. IL-8 was validated as an ATM target by its ability to rescue cell migration and invasion defects in ATM-depleted cells. Finally, ATM-depletion in human breast cancer cells reduced lung tumors in a mouse xenograft model and clinical data validated IL-8 in lung metastasis. These findings provide insights into how ATM activation by oxidative stress regulates IL-8 to sustain cell migration and invasion in cancer cells to promote metastatic potential. Thus, in addition to well-established roles in tumor suppression, these findings identify a role for ATM in tumor progression.

  16. Oxidation of uranium monocarbide in dry or moist oxygen; Cinetique d'oxydation du monocarbure d'uranium par l'oxygene sec ou humide

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, B.; Herrmann, F.J. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1968-07-01

    The kinetics of oxidation of uranium monocarbide either in dry or moist air or in oxygen-argon mixtures, has been studied thermogravimetrically, between 500 and 800 C in a circulating atmosphere. In all cases the oxidation leads to the formation of U{sub 3}O{sub 8}. Between 500 and 700 C, the activation energy is about 21 +3 kcal/mole. It seems to decrease between 700 and 800 C, but the reaction follows always a linear rate law. In moist air, the oxidation proceeds more swiftly, due to an increase in the reactional interface. An evaluation of the over-temperature has been made at 800 C. (author) [French] Nous avons etudie la cinetique d'oxydation du monocarbure d'uranium: soit par l'air sec ou humide, soit par un melange O{sub 2}/Ar (1:5) sous pression atmospherique. L'etude a effectuee par thermogravimetrie en regime dynamique dans l'intervalle de temperature: 500 - 800 C. Le comportement de UC est identique dans l'air sec et le melange O{sub 2}/Ar precedemment cites. L'oxydation conduit a la formation d'U{sub 3}O{sub 8}. Entre 500 et 700 C, l' energie d'activation est de 21 {+-}3kcal/mole: elle semble s'abaisser entre 700 et 800 C bien que dans tout le domaine de temperature (500-800 C) la reaction suive une loi cinetique lineaire. L'oxydation de UC par l'air humide semble etre plus rapide surtout aux basses temperatures. Cette acceleration n'est due, en fait, qu'a une augmentation de la surface reactionnelle. Une estimation et une mesure de la surtemperature ont ete effectuees pour une temperature de 800 C. (auteur)

  17. Analysis of phosphorylation of human heat shock factor 1 in cells experiencing a stress

    Directory of Open Access Journals (Sweden)

    Lane William S

    2005-03-01

    Full Text Available Abstract Background Heat shock factor (HSF/HSF1 not only is the transcription factor primarily responsible for the transcriptional response of cells to physical and chemical stress but also coregulates other important signaling pathways. The factor mediates the stress-induced expression of heat shock or stress proteins (HSPs. HSF/HSF1 is inactive in unstressed cells and is activated during stress. Activation is accompanied by hyperphosphorylation of the factor. The regulatory importance of this phosphorylation has remained incompletely understood. Several previous studies on human HSF1 were concerned with phosphorylation on Ser303, Ser307 and Ser363, which phosphorylation appears to be related to factor deactivation subsequent to stress, and one study reported stress-induced phosphorylation of Ser230 contributing to factor activation. However, no previous study attempted to fully describe the phosphorylation status of an HSF/HSF1 in stressed cells and to systematically identify phosphoresidues involved in factor activation. The present study reports such an analysis for human HSF1 in heat-stressed cells. Results An alanine scan of all Ser, Thr and Tyr residues of human HSF1 was carried out using a validated transactivation assay, and residues phosphorylated in HSF1 were identified by mass spectrometry and sequencing. HSF1 activated by heat treatment was phosphorylated on Ser121, Ser230, Ser292, Ser303, Ser307, Ser314, Ser319, Ser326, Ser344, Ser363, Ser419, and Ser444. Phosphorylation of Ser326 but none of the other Ser residues was found to contribute significantly to activation of the factor by heat stress. Phosphorylation on Ser326 increased rapidly during heat stress as shown by experiments using a pSer326 phosphopeptide antibody. Heat stress-induced DNA binding and nuclear translocation of a S326A substitution mutant was not impaired in HSF1-negative cells, but the mutant stimulated HSP70 expression several times less well than wild type

  18. The anaphase-promoting complex or cyclosome supports cell survival in response to endoplasmic reticulum stress.

    Directory of Open Access Journals (Sweden)

    Meifan Chen

    Full Text Available The anaphase-promoting complex or cyclosome (APC/C is a multi-subunit ubiquitin ligase that regulates exit from mitosis and G1 phase of the cell cycle. Although the regulation and function of APC/C(Cdh1 in the unperturbed cell cycle is well studied, little is known of its role in non-genotoxic stress responses. Here, we demonstrate the role of APC/C(Cdh1 (APC/C activated by Cdh1 protein in cellular protection from endoplasmic reticulum (ER stress. Activation of APC/C(Cdh1 under ER stress conditions is evidenced by Cdh1-dependent degradation of its substrates. Importantly, the activity of APC/C(Cdh1 maintains the ER stress checkpoint, as depletion of Cdh1 by RNAi impairs cell cycle arrest and accelerates cell death following ER stress. Our findings identify APC/C(Cdh1 as a regulator of cell cycle checkpoint and cell survival in response to proteotoxic insults.

  19. Response of mesenchymal stem cells to shear stress in tissue-engineered vascular grafts

    Institute of Scientific and Technical Information of China (English)

    Jian-de DONG; Yong-quan GU; Chun-min LI; Chun-ren WANG; Zeng-guo FENG; Rong-xin QIU; Bing CHEN; Jian-xin LI; Shu-wen ZHANG; Zhong-gao WANG; Jian ZHANG

    2009-01-01

    Aim: Recent studies have demonstrated that mesenchymal stem cells (MSCs) can differentiate into endothelial cells. The effect of shear stress on MSC differentiation is incompletely understood, and most studies have been based on two-dimen-sional systems. We used a model of tissue-engineered vascular grafts (TEVGs) to investigate the effects of shear stress on MSC differentiation.Methods: MSCs were isolated from canine bone marrow. The TEVG was constructed by seeding MSCs onto poly-ε-caprolactone and lactic acid (PCLA) scaffolds and subjecting them to shear stress provided by a pulsatile bioreactor for four days (two days at 1 dyne/cm2 to 15 dyne/cm2 and two days at 15 dyne/cm2).Results: Shear stress significantly increased the expression of endothelial cell markers, such as platelet-endothelial cell adhesion molecule-1 (PECAM-1), VE-cadherin, and CD34, at both the mRNA and protein levels as compared with static control cells. Protein levels of alpha-smooth muscle actin (α-SMA) and calponin were substantially reduced in shear stress-cultured cells. There was no significant change in the expression of α-SMA, smooth muscle myosin heavy chain (SMMHC)or calponin at the mRNA level.Conclusion: Shear stress upregulated the expression of endothelial cell-related markers and downregulated smooth muscle-related markers in canine MSCs. This study may serve as a basis for further investigation of the effects of shear stress on MSC differentiation in TEVGs.

  20. Matrix metalloproteinase gene expressions might be oxidative stress targets in gastric cancer cell lines

    Institute of Scientific and Technical Information of China (English)

    Salih Gencer; Anil Cebeci; Meliha Burcu Irmak-Yazicioglu

    2013-01-01

    Objective:Oxidative stress is linked to increased risk of gastric cancer and matrix metalloproteinases (MMPs) are important in the invasion and metastasis of gastric cancer.We aimed to analyze the effect of the accumulation of oxidative stress in the gastric cancer MKN-45 and 23132/87 cells following hydrogen peroxide (H2O2) exposure on the expression patterns of MMP-1,MMP-3,MMP-7,MMP-9,MMP-10,MMP-11,MMP-12,MMP-14,MMP-15,MMP-17,MMP-23,MMP-28,and β-catenin genes.Methods:The mRNA transcripts in the cells were determined by RT-PCR.Following H2O2 exposure,oxidative stress in the viable cells was analyzed by 2',7'-dichlorofluorescein diacetate (DCFH-DA).Caffeic acid phenethyl ester (CAPE) was used to eliminate oxidative stress and the consequence of H2O2 exposure and its removal on the expressions of the genes were evaluated by quantitative real-time PCR.Results:The expressions of MMP-1,MMP-7,MMP-14,MMP-15,MMP-17 and β-catenin in MKN-45 cells and only the expression of MMP-15 in 23132/87 cells were increased.Removal of the oxidative stress resulted in decrease in the expressions of MMP genes of which the expressions were increased after H2O2 exposure.β-catenin,a transcription factor for many genes including MMPs,also displayed decreased levels of expression in both of the cell lines following CAPE treatment.Conclusions:Our data suggest that there is a remarkable link between the accumulation of oxidative stress and the increased expressions of MMP genes in the gastric cancer cells and MMPs should be considered as potential targets of therapy in gastric cancers due to its continuous exposure to oxidative stress.

  1. Optimal matrix rigidity for stress-fibre polarization in stem cells

    Science.gov (United States)

    Zemel, A.; Rehfeldt, F.; Brown, A. E. X.; Discher, D. E.; Safran, S. A.

    2010-06-01

    The shape and differentiated state of many cell types are highly sensitive to the rigidity of the microenvironment. The physical mechanisms involved, however, are unknown. Here, we present a theoretical model and experiments demonstrating that the alignment of stress fibres within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix, allowing the actomyosin forces to polarize in response to elastic stresses developed in the cell. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress fibres parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress fibres in stem cells. These findings offer physical insight into the sensitivity of stem-cell differentiation to tissue elasticity and, more generally, introduce a cell-type-specific parameter for actomyosin polarizability.

  2. The Contribution of Cell Surface Components to the Neutrophil Mechanosensitivity to Shear Stresses

    Directory of Open Access Journals (Sweden)

    Michael L. Akenhead

    2015-08-01

    Full Text Available This review discusses the regulation of neutrophils by fluid shear stress in the context of factors that may govern cell mechanosensitivity and its influence on cell functions. There is substantial evidence that mechanoreceptors located on the peripheral membrane contribute to the ability of shear stress to regulate cell activity. In the case of neutrophils, the formyl peptide receptor (FPR and the CD18 integrins on the cell membrane have been shown to provide neutrophils with the ability to sense shear stresses in their local environment and alter their physiological state, accordingly. This configuration is also found for other types of cells, although they involve different cell-specific mechanoreceptors. Moreover, from an examination of the neutrophil mechanotransducing capacity, it is apparent that cellular mechanosensitivity depends on a number of factors that, if altered, contribute to dysregulation and ultimately pathophysiology. To exemplify this, we first describe the neutrophil responses to shear exposure. We then review two neutrophil mechanoreceptors, specifically FPR and CD18 integrins, which participate in controlling cell activity levels under physiological conditions. Next, we discuss the various factors that may alter neutrophil mechanosensitivity to shear stress and how these may underlie the circulatory pathobiology of two cardiovascular disease states: hypertension and hypercholesterolemia. Based on the material presented, it is conceivable that cell mechanosensitivity is a powerful global metric that permits a more efficient approach to understanding the contribution of mechanobiology to physiology and to disease processes.

  3. QUANTIFICATIVE ANALYSIS OF VIABLE, STRESSED AND DEAD CELLS OF CAMPYLOBACTER JEJUNI STRAIN 81-176

    Science.gov (United States)

    Campylobacter jejuni is an important foodborne gastrointestinal pathogen. Research has shown that changes in culturability, cell morphology, and viability occur when C. jejuni cells are subjected to stresses such as low nutrient availability, entry into stationary phase, or low CO2/high O2 condition...

  4. The clinical relevance of cell-based therapy for the treatment of stress urinary incontinence

    DEFF Research Database (Denmark)

    Gräs, Søren; Lose, Gunnar

    2011-01-01

    Stress urinary incontinence is a common disorder affecting the quality of life for millions of women worldwide. Effective surgical procedures involving synthetic permanent meshes exist, but significant short- and long-term complications occur. Cell-based therapy using autologous stem cells...

  5. Oxidative Stress Type Influences the Properties of Antioxidants Containing Polyphenols in RINm5F Beta Cells

    Directory of Open Access Journals (Sweden)

    Nathalie Auberval

    2015-01-01

    Full Text Available The in vitro methods currently used to screen bioactive compounds focus on the use of a single model of oxidative stress. However, this simplistic view may lead to conflicting results. The aim of this study was to evaluate the antioxidant properties of two natural extracts (a mix of red wine polyphenols (RWPs and epigallocatechin gallate (EGCG with three models of oxidative stress induced with hydrogen peroxide (H2O2, a mixture of hypoxanthine and xanthine oxidase (HX/XO, or streptozotocin (STZ in RINm5F beta cells. We employed multiple approaches to validate their potential as therapeutic treatment options, including cell viability, reactive oxygen species production, and antioxidant enzymes expression. All three oxidative stresses induced a decrease in cell viability and an increase in apoptosis, whereas the level of ROS production was variable depending on the type of stress. The highest level of ROS was found for the HX/XO-induced stress, an increase that was reflected by higher expression antioxidant enzymes. Further, both antioxidant compounds presented beneficial effects during oxidative stress, but EGCG appeared to be a more efficient antioxidant. These data indicate that the efficiency of natural antioxidants is dependent on both the nature of the compound and the type of oxidative stress generated.

  6. Research of the Effect of the Shear Stress on Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionCellular mechanism is one of the foundations of regenerating medicine and tissue engineering, which is also an advanced subject in cell mechanism in recent years~([1]). The form and function of a cell, and the growing, reproducing and death, even canceration are related to the characteristics of cell mechanism. While the research of the shear stress on endothelial cells is an important field in cell mechanism. The main bio-functions of endothelial cells are as follows: anti-cruor, regulating t...

  7. Role of Oxidative Stress in Stem, Cancer, and Cancer Stem Cells

    OpenAIRE

    Ahmed Abdal Dayem; Hye-Yeon Choi; Jung-Hyun Kim; Ssang-Goo Cho

    2010-01-01

    The term ‘‘oxidative stress” refers to a cell’s state characterized by excessive production of reactive oxygen species (ROS) and oxidative stress is one of the most important regulatory mechanisms for stem, cancer, and cancer stem cells. The concept of cancer stem cells arose from observations of similarities between the self-renewal mechanism of stem cells and that of cancer stem cells, but compared to normal stem cells, they are believed to have no control over the cell number. ROS have bee...

  8. Growing Out of Stress: The Role of Cell- and Organ-Scale Growth Control in Plant Water-Stress Responses.

    Science.gov (United States)

    Feng, Wei; Lindner, Heike; Robbins, Neil E; Dinneny, José R

    2016-08-01

    Water is the most limiting resource on land for plant growth, and its uptake by plants is affected by many abiotic stresses, such as salinity, cold, heat, and drought. While much research has focused on exploring the molecular mechanisms underlying the cellular signaling events governing water-stress responses, it is also important to consider the role organismal structure plays as a context for such responses. The regulation of growth in plants occurs at two spatial scales: the cell and the organ. In this review, we focus on how the regulation of growth at these different spatial scales enables plants to acclimate to water-deficit stress. The cell wall is discussed with respect to how the physical properties of this structure affect water loss and how regulatory mechanisms that affect wall extensibility maintain growth under water deficit. At a higher spatial scale, the architecture of the root system represents a highly dynamic physical network that facilitates access of the plant to a heterogeneous distribution of water in soil. We discuss the role differential growth plays in shaping the structure of this system and the physiological implications of such changes. PMID:27503468

  9. Stress relaxation microscopy (STREM): Imaging mechanical force decay in cells

    CERN Document Server

    Moreno-Flores, Susana; Vivanco, Maria dM; Toca-Herrera, Jose Luis

    2009-01-01

    We have developed a novel scanning probe-based methodology to study cell biomechanics. The time dependence of the force exerted by the cell surface on a scanning probe at constant local deformation has been used to extract local relaxational responses. The generalized Maxwell viscoelastic model that accounts for multi relaxations fully describes the mechanical behaviour of the cell surface that exhibits a bimodal relaxation. Within the range of tested forces (0.1-4 nN) a slow and a fast relaxation with characteristic times of 0.1 and 1s have been detected and assigned to rearrangements in the cell membrane and cytoskeleton cortex, respectively. Relaxation time mapping allows to simultaneously detect non-uniformities in membrane and cytoskeletal mechanical behaviour and can be used as both identifying and diagnosing tools for cell type and cell disease.

  10. Endoplasmic Reticulum Stress in the β-Cell Pathogenesis of Type 2 Diabetes

    Directory of Open Access Journals (Sweden)

    Sung Hoon Back

    2012-01-01

    Full Text Available Type 2 diabetes is a complex metabolic disorder characterized by high blood glucose in the context of insulin resistance and relative insulin deficiency by β-cell failure. Even if the mechanisms underlying the pathogenesis of β-cell failure are still under investigation, recent increasing genetic, experimental, and clinical evidence indicate that hyperactivation of the unfolded protein response (UPR to counteract metabolic stresses is closely related to β-cell dysfunction and apoptosis. Signaling pathways of the UPR are “a double-edged sword” that can promote adaptation or apoptosis depending on the nature of the ER stress condition. In this paper, we summarized our current understanding of the mechanisms and components related to ER stress in the β-cell pathogenesis of type 2 diabetes.

  11. Temperature propagation in prismatic lithium-ion-cells after short term thermal stress

    Science.gov (United States)

    Bohn, Pamina; Liebig, Gerd; Komsiyska, Lidiya; Wittstock, Gunther

    2016-05-01

    In this paper a 3D model based on the thermal material characteristics of an automotive prismatic Li-NiMnCoO2 (NMC) cell was created in COMSOL Multiphysics® in order to simulate the temperature propagation in the cell during short term thermal stress. The thermal characteristics of the battery components were experimentally determined via laser flash analysis (LFA) and differential scanning calorimetry (DSC) and used as an input parameter for the models. In order to validate the modelling approach, an experimental setup was built to measure the temperature propagation during thermal stresses within a dummy cell, equipped with temperature sensors. After validating, the model is used to describe the temperature propagation after a short-term temperature stress on automotive prismatic lithium-ion cells, simulating welding of the contact leads.

  12. The role of ER stress response on ionizing radiation-induced apoptosis in intestinal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Sang; Kim, Kwang Seok; Woo, Sang Keun; Lee, Yong Jin; Jeong, Jae Hoon; Lee, Yoon Jin; Kang, Seong Man; Lim, Young Bin [Laboratory of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2014-04-15

    Apoptosis in the intestinal epithelium is the primary pathologic factor that initiates radiation-induced intestinal injury. However, mechanism involved in ionizing radiation (IR)-induced apoptosis in the intestinal epithelium is not clearly understood. The endoplasmic reticulum (ER) stress is triggered by perturbation of the ER functions, leading to the activation of the unfolded protein response (UPR), an adaptive signaling cascade aimed at restoring ER homeostasis by facilitating the degradation of misfolded proteins and expanding the protein folding capacity of the cell. Recently, IR has also been shown to induce ER stress, thereby activating the UPR signaling pathway in intestinal epithelial cells. In this study, we report the role of ER stress responses in IR-induced intestinal epithelial cell death. We show that chemical ER stress inducers, such as tunicamycin or thapsigargin, enhance IR-induced caspase3 activation. Knockdown of xbp1 or atf6 with siRNA leads to inhibition of IR-induced caspase3 activation. Taken together, our results suggest a pro-apoptotic role of ER stress in IR-exposed intestinal epithelial cells. Our findings could contribute to the development of new strategies based on modulating ER stress responses to prevent IR-induced intestinal injury.

  13. Mediterranean diet reduces senescence-associated stress in endothelial cells

    OpenAIRE

    Marin, Carmen; Delgado-Lista, Javier; Ramirez, Rafael; Carracedo, Julia; Caballero, Javier; Perez-Martinez, Pablo; Gutierrez-Mariscal, Francisco Miguel; Garcia-Rios, Antonio; Delgado-Casado, Nieves; Cruz-Teno, Cristina; Yubero-Serrano, Elena Maria; Tinahones, Francisco; Malagon, Maria del Mar; Perez-Jimenez, Francisco; Lopez-Miranda, Jose

    2011-01-01

    This paper aims to study the effects of the oxidative stress induced by quality and quantity of dietary fat on cellular senescence. Twenty elderly subjects consumed three diets, each for 4 weeks: a saturated fatty acid diet (SFA), a low-fat and high-carbohydrate diet (CHO-ALA), and a Mediterranean diet (MedDiet) enriched in monounsaturated fatty acid following a randomized crossover design. For each diet, we investigated intracellular reactive oxidative species (ROS), cellular apoptosis and t...

  14. Membrane fluidity adjustments in ethanol-stressed Oenococcus oeni cells

    NARCIS (Netherlands)

    Silveira, da M.G.; Golovina, E.A.; Hoekstra, F.A.; Rombouts, F.M.; Abee, T.

    2003-01-01

    The effect of ethanol on the cytoplasmic membrane of Oenococcus oeni cells and the role of membrane changes in the acquired tolerance to ethanol were investigated. Membrane tolerance to ethanol was defined as the resistance to ethanol-induced leakage of preloaded carboxyfluorescein (cF) from cells.

  15. Repurposing a Prokaryotic Toxin-Antitoxin System for the Selective Killing of Oncogenically Stressed Human Cells.

    Science.gov (United States)

    Preston, Mark A; Pimentel, Belén; Bermejo-Rodríguez, Camino; Dionne, Isabelle; Turnbull, Alice; de la Cueva-Méndez, Guillermo

    2016-07-15

    Prokaryotes express intracellular toxins that pass unnoticed to carrying cells until coexpressed antitoxin partners are degraded in response to stress. Although not evolved to function in eukaryotes, one of these toxins, Kid, induces apoptosis in mammalian cells, an effect that is neutralized by its cognate antitoxin, Kis. Here we engineered this toxin-antitoxin pair to create a synthetic system that becomes active in human cells suffering a specific oncogenic stress. Inspired by the way Kid becomes active in bacterial cells, we produced a Kis variant that is selectively degraded in human cells expressing oncoprotein E6. The resulting toxin-antitoxin system functions autonomously in human cells, distinguishing those that suffer the oncogenic insult, which are killed by Kid, from those that do not, which remain protected by Kis. Our results provide a framework for developing personalized anticancer strategies avoiding off-target effects, a challenge that has been hardly tractable by other means thus far. PMID:26230535

  16. Repurposing a Prokaryotic Toxin-Antitoxin System for the Selective Killing of Oncogenically Stressed Human Cells.

    Science.gov (United States)

    Preston, Mark A; Pimentel, Belén; Bermejo-Rodríguez, Camino; Dionne, Isabelle; Turnbull, Alice; de la Cueva-Méndez, Guillermo

    2016-07-15

    Prokaryotes express intracellular toxins that pass unnoticed to carrying cells until coexpressed antitoxin partners are degraded in response to stress. Although not evolved to function in eukaryotes, one of these toxins, Kid, induces apoptosis in mammalian cells, an effect that is neutralized by its cognate antitoxin, Kis. Here we engineered this toxin-antitoxin pair to create a synthetic system that becomes active in human cells suffering a specific oncogenic stress. Inspired by the way Kid becomes active in bacterial cells, we produced a Kis variant that is selectively degraded in human cells expressing oncoprotein E6. The resulting toxin-antitoxin system functions autonomously in human cells, distinguishing those that suffer the oncogenic insult, which are killed by Kid, from those that do not, which remain protected by Kis. Our results provide a framework for developing personalized anticancer strategies avoiding off-target effects, a challenge that has been hardly tractable by other means thus far.

  17. Stress Granules Modulate SYK to Cause Microglial Cell Dysfunction in Alzheimer's Disease

    Directory of Open Access Journals (Sweden)

    Soumitra Ghosh

    2015-11-01

    Full Text Available Microglial cells in the brains of Alzheimer's patients are known to be recruited to amyloid-beta (Aβ plaques where they exhibit an activated phenotype, but are defective for plaque removal by phagocytosis. In this study, we show that microglia stressed by exposure to sodium arsenite or Aβ(1–42 peptides or fibrils form extensive stress granules (SGs to which the tyrosine kinase, SYK, is recruited. SYK enhances the formation of SGs, is active within the resulting SGs and stimulates the production of reactive oxygen and nitrogen species that are toxic to neuronal cells. This sequestration of SYK inhibits the ability of microglial cells to phagocytose Escherichia coli or Aβ fibrils. We find that aged microglial cells are more susceptible to the formation of SGs; and SGs containing SYK and phosphotyrosine are prevalent in the brains of patients with severe Alzheimer's disease. Phagocytic activity can be restored to stressed microglial cells by treatment with IgG, suggesting a mechanism to explain the therapeutic efficacy of intravenous IgG. These studies describe a mechanism by which stress, including exposure to Aβ, compromises the function of microglial cells in Alzheimer's disease and suggest approaches to restore activity to dysfunctional microglial cells.

  18. Helicobacter pylori Infection Induces Oxidative Stress and Programmed Cell Death in Human Gastric Epithelial Cells▿

    OpenAIRE

    Ding, Song-Ze; Minohara, Yutaka; Fan, Xue Jun; Wang, Jide; Reyes, Victor E; Patel, Janak; Dirden-Kramer, Bernadette; Boldogh, Istvan; Ernst, Peter B.; Crowe, Sheila E.

    2007-01-01

    Helicobacter pylori infection is associated with altered gastric epithelial cell turnover. To evaluate the role of oxidative stress in cell death, gastric epithelial cells were exposed to various strains of H. pylori, inflammatory cytokines, and hydrogen peroxide in the absence or presence of antioxidant agents. Increased intracellular reactive oxygen species (ROS) were detected using a redox-sensitive fluorescent dye, a cytochrome c reduction assay, and measurements of glutathione. Apoptosis...

  19. A Simple Force-Motion Relation for Migrating Cells Revealed by Multipole Analysis of Traction Stress

    OpenAIRE

    Tanimoto, Hirokazu; Sano, Masaki

    2014-01-01

    For biophysical understanding of cell motility, the relationship between mechanical force and cell migration must be uncovered, but it remains elusive. Since cells migrate at small scale in dissipative circumstances, the inertia force is negligible and all forces should cancel out. This implies that one must quantify the spatial pattern of the force instead of just the summation to elucidate the force-motion relation. Here, we introduced multipole analysis to quantify the traction stress dyna...

  20. AtHSPR may function in salt-induced cell death and ER stress in Arabidopsis.

    Science.gov (United States)

    Yang, Tao; Zhang, Peng; Wang, Chongying

    2016-07-01

    Salt stress is a harmful and global abiotic stress to plants and has an adverse effect on all physiological processes of plants. Recently, we cloned and identified a novel AtHSPR (Arabidopsis thaliana Heat Shock Protein Related), which encodes a nuclear-localized protein with ATPase activity, participates in salt and drought tolerance in Arabidopsis. Transcript profiling analysis revealed a differential expression of genes involved in accumulation of reactive oxygen species (ROS), abscisic acid (ABA) signaling, stress response and photosynthesis between athspr mutant and WT under salt stress. Here, we provide further analysis of the data showing the regulation of salt-induced cell death and endoplasmic reticulum (ER) stress response in Arabidopsis and propose a hypothetical model for the role of AtHSPR in the regulation of the salt tolerance in Arabidopsis. PMID:27302034

  1. ER stress transcription factor Xbp1 suppresses intestinal tumorigenesis and directs intestinal stem cells

    OpenAIRE

    Niederreiter, L.; Fritz, T. M. J.; Adolph, T. E.; Krismer, A.-M.; Offner, F. A.; Tschurtschenthaler, M.; Flak, M. B.; Hosomi, S.; Tomczak, M. F.; Kaneider, N. C.; Sarcevic, E.; Kempster, S. L.; Raine, T; Esser, D.; Rosenstiel, P.

    2013-01-01

    Unresolved endoplasmic reticulum (ER) stress in the epithelium can provoke intestinal inflammation. Hypomorphic variants of ER stress response mediators, such as X-box–binding protein 1 (XBP1), confer genetic risk for inflammatory bowel disease. We report here that hypomorphic Xbp1 function instructs a multilayered regenerative response in the intestinal epithelium. This is characterized by intestinal stem cell (ISC) expansion as shown by an inositol-requiring enzyme 1α (Ire1α)–mediated incre...

  2. Oxidative Stress Induces Endothelial Cell Senescence via Downregulation of Sirt6

    OpenAIRE

    Rong Liu; Hua Liu; Yonju Ha; Tilton, Ronald G.; Wenbo Zhang

    2014-01-01

    Accumulating evidence has shown that diabetes accelerates aging and endothelial cell senescence is involved in the pathogenesis of diabetic vascular complications, including diabetic retinopathy. Oxidative stress is recognized as a key factor in the induction of endothelial senescence and diabetic retinopathy. However, specific mechanisms involved in oxidative stress-induced endothelial senescence have not been elucidated. We hypothesized that Sirt6, which is a nuclear, chromatin-bound protei...

  3. 506 Basal T Cell Subpopulations of Normal Humans Vary by Stress Hormone Receptor Polymorphisms

    OpenAIRE

    Rehm, Kristina; Xiang, Lianbin; Marshall, Gailen

    2012-01-01

    Background Psychological stress has been correlated with allergy and asthma activity although there are clearly individual differences in the responses to the same stressor. These individual differences could be influenced by stress hormone receptor binding affinity, which could be altered by single nucleotide polymorphisms (SNPs). Methods We categorized differences in immunoregulatory profiles from peripheral blood mononuclear cells (PBMC) of 207 normal volunteers according to various glucoc...

  4. Angiogenin enhances cell migration by regulating stress fiber assembly and focal adhesion dynamics.

    Directory of Open Access Journals (Sweden)

    Saisai Wei

    Full Text Available Angiogenin (ANG acts on both vascular endothelial cells and cancer cells, but the underlying mechanism remains elusive. In this study, we carried out a co-immunoprecipitation assay in HeLa cells and identified 14 potential ANG-interacting proteins. Among these proteins, β-actin, α-actinin 4, and non-muscle myosin heavy chain 9 are stress fiber components and involved in cytoskeleton organization and movement, which prompted us to investigate the mechanism of action of ANG in cell migration. Upon confirmation of the interactions between ANG and the three proteins, further studies revealed that ANG co-localized with β-actin and α-actinin 4 at the leading edge of migrating cells. Down-regulation of ANG resulted in fewer but thicker stress fibers with less dynamics, which was associated with the enlargements of focal adhesions. The focal adhesion kinase activity and cell migration capacity were significantly decreased in ANG-deficient cells. Taken together, our data demonstrated that the existence of ANG in the cytoplasm optimizes stress fiber assembly and focal adhesion formation to accommodate cell migration. The finding that ANG promoted cancer cell migration might provide new clues for tumor metastasis research.

  5. The role of DJ-1 in the oxidative stress cell death cascade after stroke

    Institute of Scientific and Technical Information of China (English)

    Paolina Pantcheva; Maya Elias; Kelsey Duncan; Cesar V.Borlongan; Naoki Tajiri; Yuji Kaneko

    2014-01-01

    Oxidative stress is closely associated with secondary cell death in many disorders of the central nervous system including stroke, Parkinson’s disease, Alzheimer’s disease. Among many aber-rant oxidative stress-associated proteins, DJ-1 has been associated with the oxidative stress cell death cascade primarily in Parkinson’s disease. Although principally expressed in the cytoplasm and nucleus, DJ-1 can be secreted into the serum under pathological condition. Recently, a close pathological association between DJ-1 and oxidative stress in stroke has been implicated. To this end, we and others have demonstrated the important role of mitochondria in neuroprotection for stroke by demonstrating that the translocation of DJ-1 in the mitochondria could potentially mitigate mitochondrial injury. Here, we discuss our recent ifndings testing the hypothesis that DJ-1 not only functions as a form of intracellular protection from oxidative stress, but that it also utilizes paracrine and/or autocrine cues in order to accomplish extracellular signaling between neighboring neuronal cells, resulting in neuroprotection. This article highlights recent evidence supporting the status of DJ-1 as key anti-oxidative stress therapeutic target for stroke.

  6. Laparotomy in mice induces blood cell expression of inflammatory and stress genes.

    Science.gov (United States)

    Ko, Fred; Isoda, Fumiko; Mobbs, Charles

    2015-04-01

    Surgical trauma induces immune and stress responses although its effects on postsurgical inflammatory and stress gene expression remain poorly characterized. This study sought to improve current scientific knowledge by investigating the effects of laparotomy on mouse blood cell inflammatory and stress gene expression. Three-month-old male C57BL/6J mice were subjected to 2% isoflurane or 2% isoflurane with laparotomy and sacrificed 4 h postintervention. Blood was collected and blood cell expression of 158 genes central to inflammatory and stress responses was assayed using quantitative polymerase chain reaction arrays. Mice subjected to isoflurane with laparotomy, compared with mice receiving isoflurane alone, had >2-fold upregulation of genes in inflammation (Osm, IL1rn, IL1b, and Csf1), oxidative stress (Hmox1), heat shock (Hspa1b), growth arrest (Cdkn1a), and DNA repair (Ugt1a2). These genes demonstrated similar expression patterns by Pearson correlation and cluster analysis. Thus, laparotomy induces coordinated, postsurgical blood cell expression of unique inflammatory and stress genes whose roles in influencing surgical outcomes need further investigation.

  7. Diffusible Factors Secreted by Glioblastoma and Medulloblastoma Cells Induce Oxidative Stress in Bystander Neural Stem Progenitors.

    Science.gov (United States)

    Sharma, Neha; Colangelo, Nicholas W; de Toledo, Sonia M; Azzam, Edouard I

    2016-08-01

    Harmful effects that alter the homeostasis of neural stem or progenitor cells (NSPs) can affect regenerative processes in the central nervous system. We investigated the effect of soluble factors secreted by control or (137)Cs-γ-irradiated glioblastoma or medulloblastoma cells on redox-modulated endpoints in recipient human NSPs. Growth medium harvested from the nonirradiated brain tumor cells, following 24 h of growth, induced prominent oxidative stress in recipient NSPs as judged by overall increases in mitochondrial superoxide radical levels (p p21(Waf1) and p27(Kip1), and perturbations in cell cycle progression (p cells to radiation only slightly altered the induced oxidative changes in the bystander NSPs, except for medium from irradiated medulloblastoma cells that was more potent at inducing apoptosis in the NSPs than medium from nonirradiated cells (p cells is often used to support the growth of stem cells.

  8. Lithium induces ER stress and N-glycan modification in galactose-grown Jurkat cells.

    Directory of Open Access Journals (Sweden)

    Tamás Nagy

    Full Text Available We previously reported that lithium had a significant impact on Ca(2+ regulation and induced unfolded protein response (UPR in yeast cells grown on galactose due to inhibition of phosphoglucomutase (PGM, however the exact mechanism has not been established yet. In this study, we analysed lithium's effect in galactose-fed cells to clarify whether these ER-related changes are the result of a relative hypoglycemic state. Furthermore, we investigated whether the alterations in galactose metabolism impact protein post-translational modifications. Thus, Jurkat cells were incubated in glucose or galactose containing media with or without lithium treatment. We found that galactose-fed and lithium treated cells showed better survivability than fasting cells. We also found higher UDP-Hexose and glycogen levels in these cells compared to fasting cells. On the other hand, the UPR (X-box binding protein 1 mRNA levels of galactose-fed and lithium treated cells was even greater than in fasting cells. We also found increased amount of proteins that contained N-linked N-acetyl-glucosamine, similar to what was reported in fasting cells by a recent study. Our results demonstrate that lithium treatment of galactose-fed cells can induce stress responses similar to hypoglycemia, however cell survival is still secured by alternative pathways. We propose that clarifying this process might be an important addition toward the better understanding of the molecular mechanisms that regulate ER-associated stress response.

  9. The Stress Granule RNA-Binding Protein TIAR-1 Protects Female Germ Cells from Heat Shock in Caenorhabditis elegans

    OpenAIRE

    Gabriela Huelgas-Morales; Carlos Giovanni Silva-García; Laura S. Salinas; David Greenstein; Navarro, Rosa E.

    2016-01-01

    In response to stressful conditions, eukaryotic cells launch an arsenal of regulatory programs to protect the proteome. One major protective response involves the arrest of protein translation and the formation of stress granules, cytoplasmic ribonucleoprotein complexes containing the conserved RNA-binding proteins TIA-1 and TIAR. The stress granule response is thought to preserve mRNA for translation when conditions improve. For cells of the germline—the immortal cell lineage required for se...

  10. Ethylene is involved in stress responses induced by fusicoccin in sycamore cultured cells.

    Science.gov (United States)

    Malerba, Massimo; Crosti, Paolo; Cerana, Raffaella

    2010-11-15

    The phytohormone ethylene is involved in many physiological and developmental processes of plants, as well as in stress responses and in the development of disease resistance. Fusicoccin (FC) is a well-known phytotoxin, that in sycamore (Acer pseudoplatanus L.) cultured cells, induces a set of stress responses, including synthesis of ethylene. In this study, we investigated the possible involvement of ethylene in the FC-induced stress responses of sycamore cells by means of Co(2+), a well-known specific inhibitor of ethylene biosynthesis. Co(2+) inhibited the accumulation of dead cells in the culture, the production of nitric oxide (NO) and of the molecular chaperone Binding Protein (BiP) in the endoplasmic reticulum induced by FC. By contrast, Co(2+) was ineffective on the FC-induced accumulation of cells with fragmented DNA, production of H(2)O(2) and release of cytochrome c from the mitochondrion, and only partially reduced the accumulation of regulative 14-3-3 proteins in the cytosol. In addition, we compared the effect of FC on the above parameters with that of the ethylene-releasing compound ethephon (2-chloroethane phosphonic acid). The results suggest that ethylene is involved in several stress responses induced by FC in sycamore cells, including a form of cell death that does not show apoptotic features and possibly involves NO as a signaling molecule.

  11. Endoplasmic reticulum stress activation mediates Ginseng Rg3-induced anti-gallbladder cancer cell activity.

    Science.gov (United States)

    Wu, Keren; Li, Ning; Sun, Huaqin; Xu, Tao; Jin, Fa; Nie, Jifeng

    2015-10-23

    In the current study, we examined the potential effect of Ginsenoside Rg3 against gallbladder cancer cells, the underlying signaling mechanisms were also studied. We demonstrated that Rg3 exerted potent cytotoxic and pro-apoptotic activity against established and primary human gallbladder cancer cells. Yet it was safe to non-cancerous gallbladder epithelial cells. At the molecular level, we showed that Rg3 induced endoplasmic reticulum (ER) stress activation, the latter was evidenced by C/EBP homologous protein (CHOP) upregulation, inositol-requiring enzyme 1 (IRE1)/PKR-like endoplasmic reticulum kinase (PERK) phosphorylations, and caspase-12 activation in gallbladder cancer cells. Reversely, the ER stress inhibitor salubrinal, the caspase-12 inhibitor z-ATAD-fmk as well as CHOP shRNA knockdown significantly attenuated Rg3-induced cytotoxicity against gallbladder cancer cells. In vivo, we showed that Rg3 oral administration significantly inhibited GBC-SD gallbladder cancer xenograft growth in nude mice, its activity was, however, compromised with co-administration of the ER stress inhibitor salubrinal. Thus, we suggest that ER stress activation mediates Ginseng Rg3-induced anti-gallbladder cancer cell activity in vitro and in vivo. PMID:26361144

  12. Astaxanthin Protects Steroidogenesis from Hydrogen Peroxide-Induced Oxidative Stress in Mouse Leydig Cells

    Directory of Open Access Journals (Sweden)

    Jyun-Yuan Wang

    2015-03-01

    Full Text Available Androgens, especially testosterone produced in Leydig cells, play an essential role in development of the male reproductive phenotype and fertility. However, testicular oxidative stress may cause a decline in testosterone production. Many antioxidants have been used as reactive oxygen species (ROS scavengers to eliminate oxidative stress to protect steroidogenesis. Astaxanthin (AST, a natural extract from algae and plants ubiquitous in the marine environment, has been shown to have antioxidant activity in many previous studies. In this study, we treated primary mouse Leydig cells or MA-10 cells with hydrogen peroxide (H2O2 to cause oxidative stress. Testosterone and progesterone production was suppressed and the expression of the mature (30 kDa form of StAR protein was down-regulated in MA-10 cells by H2O2 and cAMP co-treatment. However, progesterone production and expression of mature StAR protein were restored in MA-10 cells by a one-hour pretreatment with AST. AST also reduced ROS levels in cells so that they were lower than the levels in untreated controls. These results provide additional evidence of the potential health benefits of AST as a potential food additive to ease oxidative stress.

  13. When supply does not meet demand-ER stress and plant programmed cell death

    Science.gov (United States)

    Williams, Brett; Verchot, Jeanmarie; Dickman, Martin B.

    2014-01-01

    The endoplasmic reticulum (ER) is the central organelle in the eukaryotic secretory pathway. The ER functions in protein synthesis and maturation and is crucial for proper maintenance of cellular homeostasis and adaptation to adverse environments. Acting as a cellular sentinel, the ER is exquisitely sensitive to changing environments principally via the ER quality control machinery. When perturbed, ER-stress triggers a tightly regulated and highly conserved, signal transduction pathway known as the unfolded protein response (UPR) that prevents the dangerous accumulation of unfolded/misfolded proteins. In situations where excessive UPR activity surpasses threshold levels, cells deteriorate and eventually trigger programmed cell death (PCD) as a way for the organism to cope with dysfunctional or toxic signals. The programmed cell death that results from excessive ER stress in mammalian systems contributes to several important diseases including hypoxia, neurodegeneration, and diabetes. Importantly, hallmark features and markers of cell death that are associated with ER stress in mammals are also found in plants. In particular, there is a common, conserved set of chaperones that modulate ER cell death signaling. Here we review the elements of plant cell death responses to ER stress and note that an increasing number of plant-pathogen interactions are being identified in which the host ER is targeted by plant pathogens to establish compatibility. PMID:24926295

  14. The Role of Plant Cell Wall Proteins in Response to Salt Stress

    Directory of Open Access Journals (Sweden)

    Lyuben Zagorchev

    2014-01-01

    Full Text Available Contemporary agriculture is facing new challenges with the increasing population and demand for food on Earth and the decrease in crop productivity due to abiotic stresses such as water deficit, high salinity, and extreme fluctuations of temperatures. The knowledge of plant stress responses, though widely extended in recent years, is still unable to provide efficient strategies for improvement of agriculture. The focus of study has been shifted to the plant cell wall as a dynamic and crucial component of the plant cell that could immediately respond to changes in the environment. The investigation of plant cell wall proteins, especially in commercially important monocot crops revealed the high involvement of this compartment in plants stress responses, but there is still much more to be comprehended. The aim of this review is to summarize the available data on this issue and to point out the future areas of interest that should be studied in detail.

  15. Dichloroacetate Decreases Cell Health and Activates Oxidative Stress Defense Pathways in Rat Alveolar Type II Pneumocytes

    Directory of Open Access Journals (Sweden)

    Alexis Valauri-Orton

    2015-01-01

    Full Text Available Dichloroacetate (DCA is a water purification byproduct that is known to be hepatotoxic and hepatocarcinogenic and to induce peripheral neuropathy and damage macrophages. This study characterizes the effects of the haloacetate on lung cells by exposing rat alveolar type II (L2 cells to 0–24 mM DCA for 6–24 hours. Increasing DCA concentration and the combination of increasing DCA concentration plus longer exposures decrease measures of cellular health. Length of exposure has no effect on oxidative stress biomarkers, glutathione, SOD, or CAT. Increasing DCA concentration alone does not affect total glutathione or its redox ratio but does increase activity in the SOD/CAT oxidative stress defense pathway. These data suggest that alveolar type II cells rely on SOD and CAT more than glutathione to combat DCA-induced stress.

  16. Chronic stress in adulthood followed by intermittent stress impairs spatial memory and the survival of newborn hippocampal cells in aging animals: prevention by FGL, a peptide mimetic of neural cell adhesion molecule

    DEFF Research Database (Denmark)

    Borcel, Erika; Pérez-Alvarez, Laura; Herrero, Ana Isabel;

    2008-01-01

    In this study, we examined whether chronic stress in adulthood can exert long-term effects on spatial-cognitive abilities and on the survival of newborn hippocampal cells in aging animals. Male Wistar rats were subjected to chronic unpredictable stress at midlife (12 months old) and then reexposed...... each week to a stress stimulus. When evaluated in the water maze at the early stages of aging (18 months old), chronic unpredictable stress accelerated spatial-cognitive decline, an effect that was accompanied by a reduction in the survival of newborn cells and in the number of adult granular cells......, a peptide mimetic of neural cell adhesion molecule, during the 4 weeks of continuous stress not only prevented the deleterious effects of chronic stress on spatial memory, but also reduced the survival of the newly generated hippocampal cells in aging animals. FGL treatment did not, however, prevent...

  17. Molecular mechanisms of Saccharomyces cerevisiae stress adaptation and programmed cell death in response to acetic acid

    Directory of Open Access Journals (Sweden)

    Sergio eGiannattasio

    2013-02-01

    Full Text Available Beyond its classical biotechnological applications such as food and beverage production or as a cell factory, the yeast Saccharomyces cerevisiae is a valuable model organism to study fundamental mechanisms of cell response to stressful environmental changes. Acetic acid is a physiological product of yeast fermentation and it is a well-known food preservative due to its antimicrobial action. Acetic acid has recently been shown to cause yeast cell death and aging. Here we shall focus on the molecular mechanisms of S. cerevisiae stress adaptation and programmed cell death in response to acetic acid. We shall elaborate on the intracellular signaling pathways involved in the cross-talk of pro-survival and pro-death pathways underlying the importance of understanding fundamental aspects of yeast cell homeostasis to improve the performance of a given yeast strain in biotechnological applications.

  18. IL-13 Augments Compressive Stress-Induced Tissue Factor Expression in Human Airway Epithelial Cells.

    Science.gov (United States)

    Mitchel, Jennifer A; Antoniak, Silvio; Lee, Joo-Hyeon; Kim, Sae-Hoon; McGill, Maureen; Kasahara, David I; Randell, Scott H; Israel, Elliot; Shore, Stephanie A; Mackman, Nigel; Park, Jin-Ah

    2016-04-01

    Tissue factor (TF) is best known as a cellular initiator of coagulation, but it is also a multifunctional protein that has been implicated in multiple pathophysiologic conditions, including asthma. In the lung, airway epithelial cells express TF, but it is unknown how TF expression is regulated by asthma-associated mediators. We investigated the role of IL-13, a type 2 cytokine, alone and in combination with compressive stress, which mimics asthmatic bronchoconstriction, on TF expression and release of TF-positive extracellular vesicles from primary normal human bronchial epithelial cells. Well-differentiated normal human bronchial epithelial cells were treated with IL-13 and compressive stress, alone and in combination. TF mRNA, protein and activity were measured in the cells and conditioned media. TF was also measured in the bronchoalveolar lavage (BAL) fluid of allergen-challenged mice and patients with asthma. IL-13 and compressive stress increased TF expression, but only compressive stress induced TF-positive extracellular vesicle release. Pretreatment with IL-13 augmented compressive stress-induced TF expression and release. TF protein and activity in BAL fluid were increased in allergen-sensitized and -challenged mice. TF was elevated in the BAL fluid of patients with mild asthma after an allergen challenge. Our in vitro and in vivo data indicate close cooperation between mechanical and inflammatory stimuli on TF expression and release of TF-positive extracellular vesicles in the lungs, which may contribute to pathophysiology of asthma. PMID:26407210

  19. From microgravity to osmotic conditions: mechanical integration of plant cells in response to stress

    Science.gov (United States)

    Wojtaszek, Przemyslaw; Kasprowicz, Anna; Michalak, Michal; Janczara, Renata; Volkmann, Dieter; Baluska, Frantisek

    Chemical reactions and interactions between molecules are commonly thought of as being at the basis of Life. Research of recent years, however, is more and more evidently indicating that physical forces are profoundly affecting the functioning of life at all levels of its organiza-tion. To detect and to respond to such forces, plant cells need to be integrated mechanically. Cell walls are the outermost functional zone of plant cells. They surround the individual cells, and also form a part of the apoplast. In cell suspensions, cell walls are embedded in the cul-ture medium which can be considered as a superapoplast. Through physical and chemical interactions they provide a basis for the structural and functional cell wall-plasma membrane-cytoskeleton (WMC) continuum spanning the whole cell. Here, the working of WMC contin-uum, and the participation of signalling molecules, like NO, would be presented in the context of plant responses to stress. In addition, the effects of the changing composition of WMC continuum will be considered, with particular attention paid to the modifications of the WMC components. Plant cells are normally adapted to changing osmotic conditions, resulting from variable wa-ter availability. The appearance of the osmotic stress activates adaptory mechanisms. If the strength of osmotic stress grows relatively slowly over longer period of time, the cells are able to adapt to conditions that are lethal to non-adapted cells. During stepwise adaptation of tobacco BY-2 suspension cells to the presence of various osmotically active agents, cells diverged into independent, osmoticum type-specific lines. In response to ionic agents (NaCl, KCl), the adhe-sive properties were increased and randomly dividing cells formed clumps, while cells adapted to nonionic osmotica (mannitol, sorbitol, PEG) revealed ordered pattern of precisely positioned cell divisions, resulting in the formation of long cell files. Changes in the growth patterns were accompanied by

  20. Cell division plane orientation based on tensile stress in Arabidopsis thaliana

    Science.gov (United States)

    Louveaux, Marion; Julien, Jean-Daniel; Mirabet, Vincent; Boudaoud, Arezki; Hamant, Olivier

    2016-01-01

    Cell geometry has long been proposed to play a key role in the orientation of symmetric cell division planes. In particular, the recently proposed Besson–Dumais rule generalizes Errera’s rule and predicts that cells divide along one of the local minima of plane area. However, this rule has been tested only on tissues with rather local spherical shape and homogeneous growth. Here, we tested the application of the Besson–Dumais rule to the divisions occurring in the Arabidopsis shoot apex, which contains domains with anisotropic curvature and differential growth. We found that the Besson–Dumais rule works well in the central part of the apex, but fails to account for cell division planes in the saddle-shaped boundary region. Because curvature anisotropy and differential growth prescribe directional tensile stress in that region, we tested the putative contribution of anisotropic stress fields to cell division plane orientation at the shoot apex. To do so, we compared two division rules: geometrical (new plane along the shortest path) and mechanical (new plane along maximal tension). The mechanical division rule reproduced the enrichment of long planes observed in the boundary region. Experimental perturbation of mechanical stress pattern further supported a contribution of anisotropic tensile stress in division plane orientation. Importantly, simulations of tissues growing in an isotropic stress field, and dividing along maximal tension, provided division plane distributions comparable to those obtained with the geometrical rule. We thus propose that division plane orientation by tensile stress offers a general rule for symmetric cell division in plants. PMID:27436908

  1. Cerium fluoride nanoparticles protect cells against oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Shcherbakov, Alexander B.; Zholobak, Nadezhda M. [Zabolotny Institute of Microbiology and Virology, National Academy of Sciences of Ukraine, Kyiv D0368 (Ukraine); Baranchikov, Alexander E. [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); Ryabova, Anastasia V. [Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow 115409 (Russian Federation); Ivanov, Vladimir K., E-mail: van@igic.ras.ru [Kurnakov Institute of General and Inorganic Chemistry of the Russian Academy of Sciences, Moscow 119991 (Russian Federation); National Research Tomsk State University, Tomsk 634050 (Russian Federation)

    2015-05-01

    A novel facile method of non-doped and fluorescent terbium-doped cerium fluoride stable aqueous sols synthesis is proposed. Intense green luminescence of CeF{sub 3}:Tb nanoparticles can be used to visualize these nanoparticles' accumulation in cells using confocal laser scanning microscopy. Cerium fluoride nanoparticles are shown for the first time to protect both organic molecules and living cells from the oxidative action of hydrogen peroxide. Both non-doped and terbium-doped CeF{sub 3} nanoparticles are shown to provide noteworthy protection to cells against the vesicular stomatitis virus. - Highlights: • Facile method of CeF{sub 3} and CeF{sub 3}:Tb stable aqueous sols synthesis is proposed. • Naked CeF{sub 3} nanoparticles are shown to be non-toxic and to protect cells from the action of H{sub 2}O{sub 2}. • CeF{sub 3} and CeF{sub 3}:Tb nanoparticles are shown to protect living cells against the vesicular stomatitis virus.

  2. Beta-cell mitochondrial carriers and the diabetogenic stress response.

    Science.gov (United States)

    Brun, Thierry; Maechler, Pierre

    2016-10-01

    Mitochondria play a central role in pancreatic beta-cells by coupling metabolism of the secretagogue glucose to distal events of regulated insulin exocytosis. This process requires transports of both metabolites and nucleotides in and out of the mitochondria. The molecular identification of mitochondrial carriers and their respective contribution to beta-cell function have been uncovered only recently. In type 2 diabetes, mitochondrial dysfunction is an early event and may precipitate beta-cell loss. Under diabetogenic conditions, characterized by glucotoxicity and lipotoxicity, the expression profile of mitochondrial carriers is selectively modified. This review describes the role of mitochondrial carriers in beta-cells and the selective changes in response to glucolipotoxicity. In particular, we discuss the importance of the transfer of metabolites (pyruvate, citrate, malate, and glutamate) and nucleotides (ATP, NADH, NADPH) for beta-cell function and dysfunction. This article is part of a Special Issue entitled: Mitochondrial Channels edited by Pierre Sonveaux, Pierre Maechler and Jean-Claude Martinou. PMID:26979549

  3. [Carbonyl stress and oxidatively modified proteins in chronic renal failure].

    Science.gov (United States)

    Bargnoux, A-S; Morena, M; Badiou, S; Dupuy, A-M; Canaud, B; Cristol, J-P

    2009-01-01

    Oxidative stress is commonly observed in chronic renal failure patients resulting from an unbalance between overproduction of reactive oxygen species and impairement of defense mechanisms. Proteins appear as potential targets of uremia-induced oxidative stress and may undergo qualitative modifications. Proteins could be directly modified by reactive oxygen species which leads to amino acid oxydation and cross-linking. Proteins could be indirectly modified by reactive carbonyl compounds produced by glycoxidation and lipo-peroxidation. The resulting post-traductional modifications are known as carbonyl stress. In addition, thiols could be oxidized or could react with homocystein leading to homocysteinylation. Finally, tyrosin could be oxidized by myeloperoxidase leading to advanced oxidative protein products (AOPP). Oxidatively modified proteins are increased in chronic renal failure patients and may contribute to exacerbate the oxidative stress/inflammation syndrome. They have been involved in long term complications of uremia such as amyloidosis and accelerated atherosclerosis. PMID:19297289

  4. Optical studies of oxidative stress in pulmonary artery endothelial cells

    Science.gov (United States)

    Ghanian, Zahra; Sepehr, Reyhaneh; Eis, Annie; Kondouri, Ganesh; Ranji, Mahsa

    2015-03-01

    Reactive oxygen species (ROS) play an essential role in facilitating signal transduction processes within the cell and modulating the injuries. However, the generation of ROS is tightly controlled both spatially and temporally within the cell, making the study of ROS dynamics particularly difficult. This study present a novel protocol to quantify the dynamic of the mitochondrial superoxide as a precursor of reactive oxygen species. To regulate the mitochondrial superoxide level, metabolic perturbation was induced by administration of potassium cyanide (KCN). The presented method was able to monitor and measure the superoxide production rate over time. Our results demonstrated that the metabolic inhibitor, potassium cyanide (KCN) induced a significant increase in the rate of superoxide production in mitochondria of fetal pulmonary artery endothelial cells (FPAEC). Presented method sets the stage to study different ROS mediated injuries in vitro.

  5. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    Science.gov (United States)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  6. Investigation of reliability attributes and accelerated stress factors of terrestrial solar cells. Second annual report

    Energy Technology Data Exchange (ETDEWEB)

    Lathrop, J.W.; Prince, J.L.

    1980-04-01

    The work covered in this report represents the second year's effort of a continuing program to determine the reliability attributes of terrestrial solar cells. Three main tasks were undertaken during the reporting period: (1) a study of the electrical behavior of cells in the second (reverse) quadrant, (2) the accelerated stress testing of three new state of the art cells and (3) the continued bias-temperature testing of four Block II type silicon cells at 78/sup 0/C and 135/sup 0/C. Electrical characteristics measured in the second quadrant were determined to be a function of the cell's thermal behavior with breakdown depending on the initiation of localized heating. This implied that high breakdown cells may be more fault tolerant when forced to operate in the second quadrant - a result contrary to conventional thinking. The accelerated stress tests used in the first (power) quadrant were bias-temperature, bias-temperature-humidity, temperature-humidity, thermal shock, and thermal cycle. The new type cells measured included an EFG cell, a polycrystalline cell, and a Czochralski cell. Electrical parameters measured included I/sub SC/, V/sub OC/, P/sub M/, and I/sub M/. Incorporated in the report are the distributions of prestress electrical data for all cell types. Significant differences in the response to the various stress tests were observed between cell types. A microprocessed controlled, short interval solar cell tester was designed and construction initiated on a prototype for use in the program.

  7. The influence of calreticulin on oxidative stress i n MCF-7 cells

    Directory of Open Access Journals (Sweden)

    Sree Jaya S

    2014-09-01

    Full Text Available Calreticulin (CRT, a multifunctional protein that regulates varied important cell functions, in addition CRT recently drawn notice that the function of oxidative stress induced apoptosis. At this point, the role of CRT through oxidative stress mediated apoptotic cell death is focused. Herein, we used mammary gland adenocarcinoma cell cells (MCF-7 in vitroto investigate the role CRT overexpression in cell death by promoting ROS induced apoptosis. Human CRT gene was isolated from blood, cDNA was synthesized, CRT was cloned to the XhoI/EcoRI restriction sites of a mammalian expression vector pcDNA 3.1 and plasmid was transfected in to MCF-7 cell line to promote apoptosis. After 24 h and 48 h transfection, cell proliferation, LDH leakage, lipid peroxidation, total protein, and glutathione concentrations were measured. CRT transfected cells expressed higher concentrations of lipid peroxidation and LDHleakage than control MCF -7 cells. There was a significant negative correlation between lipid peroxidation and cell proliferation. Glutathione did not appear to be a significant factor. Therefore, stimulation of CRT may modulate the growth inhibitory effects in human breast cancer cells. One mechanism of growth inhibition may be through increased lipid peroxidation.

  8. Pycnogenol (PYC) induces apoptosis in human fibrosarcoma (HFS) cells under metal-mediated oxidative stress.

    Science.gov (United States)

    Park, Yeon Sun; Kim, Young Gon

    2011-01-01

    Pycnogenol (PYC), polyphenolic compounds with antioxidant activity, acted as a prooxidant. PYC caused oxidative stress in human fibrosarcoma cells (HFS) when administered following pretreatment with iron chloride. The generated reactive oxygen species (ROS) caused the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in DNA and resulted in more apoptosis in HFS cells than in the human fibroblastoma (HFB) cells. DNA damage and cellular viability at different PYC concentrations were closely consistent with cell growth, high performance liquid chromatography (HPLC), Enzyme Linked Immunosorbent Assay (ELISA) and assays of two major antioxidant enzymes, superoxide dismutase (SOD) and catalase. Although the presence of PYC induced total SOD and catalase activities under oxidative stress in dose dependent fashion, more apoptotic cells were induced in HFS cells with increased [8-OHdG] than in HFB cells. The results suggest that PYC selectively induced cell death in HFS cells. This further confirmed that PYC-induced apoptosis is mediated primarily through the activation of caspase-3 apoptotic marker in HFS cells but not in HFB cells. We conclude that PYC would behave as either antioxidant or prooxidant dependant upon the cellular types. PMID:22754951

  9. Multivariate analyses of salt stress and metabolite sensing in auto- and heterotroph Chenopodium cell suspensions.

    Science.gov (United States)

    Wongchai, C; Chaidee, A; Pfeiffer, W

    2012-01-01

    Global warming increases plant salt stress via evaporation after irrigation, but how plant cells sense salt stress remains unknown. Here, we searched for correlation-based targets of salt stress sensing in Chenopodium rubrum cell suspension cultures. We proposed a linkage between the sensing of salt stress and the sensing of distinct metabolites. Consequently, we analysed various extracellular pH signals in autotroph and heterotroph cell suspensions. Our search included signals after 52 treatments: salt and osmotic stress, ion channel inhibitors (amiloride, quinidine), salt-sensing modulators (proline), amino acids, carboxylic acids and regulators (salicylic acid, 2,4-dichlorphenoxyacetic acid). Multivariate analyses revealed hirarchical clusters of signals and five principal components of extracellular proton flux. The principal component correlated with salt stress was an antagonism of γ-aminobutyric and salicylic acid, confirming involvement of acid-sensing ion channels (ASICs) in salt stress sensing. Proline, short non-substituted mono-carboxylic acids (C2-C6), lactic acid and amiloride characterised the four uncorrelated principal components of proton flux. The proline-associated principal component included an antagonism of 2,4-dichlorphenoxyacetic acid and a set of amino acids (hydrophobic, polar, acidic, basic). The five principal components captured 100% of variance of extracellular proton flux. Thus, a bias-free, functional high-throughput screening was established to extract new clusters of response elements and potential signalling pathways, and to serve as a core for quantitative meta-analysis in plant biology. The eigenvectors reorient research, associating proline with development instead of salt stress, and the proof of existence of multiple components of proton flux can help to resolve controversy about the acid growth theory. PMID:21974771

  10. Control of Oxidative Stress and Generation of Induced Pluripotent Stem Cell-like Cells by Jun Dimerization Protein 2

    International Nuclear Information System (INIS)

    We report here that the Jun dimerization protein 2 (JDP2) plays a critical role as a cofactor for the transcription factors nuclear factor-erythroid 2-related factor 2 (Nrf2) and MafK in the regulation of the antioxidants and production of reactive oxygen species (ROS). JDP2 associates with Nrf2 and MafK (Nrf2-MafK) to increase the transcription of antioxidant response element-dependent genes. Oxidative-stress-inducing reagent led to an increase in the intracellular accumulation of ROS and cell proliferation in Jdp2 knock-out mouse embryonic fibroblasts. In Jdp2-Cre mice mated with reporter mice, the expression of JDP2 was restricted to granule cells in the brain cerebellum. The induced pluripotent stem cells (iPSC)-like cells were generated from DAOY medulloblastoma cell by introduction of JDP2, and the defined factor OCT4. iPSC-like cells expressed stem cell-like characteristics including alkaline phosphatase activity and some stem cell markers. However, such iPSC-like cells also proliferated rapidly, became neoplastic, and potentiated cell malignancy at a later stage in SCID mice. This study suggests that medulloblastoma cells can be reprogrammed successfully by JDP2 and OCT4 to become iPSC-like cells. These cells will be helpful for studying the generation of cancer stem cells and ROS homeostasis

  11. Control of Oxidative Stress and Generation of Induced Pluripotent Stem Cell-like Cells by Jun Dimerization Protein 2

    Directory of Open Access Journals (Sweden)

    Naoto Yamaguchi

    2013-07-01

    Full Text Available We report here that the Jun dimerization protein 2 (JDP2 plays a critical role as a cofactor for the transcription factors nuclear factor-erythroid 2-related factor 2 (Nrf2 and MafK in the regulation of the antioxidants and production of reactive oxygen species (ROS. JDP2 associates with Nrf2 and MafK (Nrf2-MafK to increase the transcription of antioxidant response element-dependent genes. Oxidative-stress-inducing reagent led to an increase in the intracellular accumulation of ROS and cell proliferation in Jdp2 knock-out mouse embryonic fibroblasts. In Jdp2-Cre mice mated with reporter mice, the expression of JDP2 was restricted to granule cells in the brain cerebellum. The induced pluripotent stem cells (iPSC-like cells were generated from DAOY medulloblastoma cell by introduction of JDP2, and the defined factor OCT4. iPSC-like cells expressed stem cell-like characteristics including alkaline phosphatase activity and some stem cell markers. However, such iPSC-like cells also proliferated rapidly, became neoplastic, and potentiated cell malignancy at a later stage in SCID mice. This study suggests that medulloblastoma cells can be reprogrammed successfully by JDP2 and OCT4 to become iPSC-like cells. These cells will be helpful for studying the generation of cancer stem cells and ROS homeostasis.

  12. Control of Oxidative Stress and Generation of Induced Pluripotent Stem Cell-like Cells by Jun Dimerization Protein 2

    Energy Technology Data Exchange (ETDEWEB)

    Chiou, Shyh-Shin, E-mail: chiouss@kmu.edu.tw [Division of Hematology-Oncology, Department of Pediatrics, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Department of Pediatrics, Faculty of Medicine, School of Medicine, Kaohsiung Medical University, 807 Kaohsiung 807, Taiwan (China); Wang, Sophie Sheng-Wen; Wu, Deng-Chyang [Department of Gastroenterology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Lin, Ying-Chu [School of Dentistry, College of Dentistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Kao, Li-Pin [Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, 807 Kaohsiung 807, Taiwan (China)

    2013-07-26

    We report here that the Jun dimerization protein 2 (JDP2) plays a critical role as a cofactor for the transcription factors nuclear factor-erythroid 2-related factor 2 (Nrf2) and MafK in the regulation of the antioxidants and production of reactive oxygen species (ROS). JDP2 associates with Nrf2 and MafK (Nrf2-MafK) to increase the transcription of antioxidant response element-dependent genes. Oxidative-stress-inducing reagent led to an increase in the intracellular accumulation of ROS and cell proliferation in Jdp2 knock-out mouse embryonic fibroblasts. In Jdp2-Cre mice mated with reporter mice, the expression of JDP2 was restricted to granule cells in the brain cerebellum. The induced pluripotent stem cells (iPSC)-like cells were generated from DAOY medulloblastoma cell by introduction of JDP2, and the defined factor OCT4. iPSC-like cells expressed stem cell-like characteristics including alkaline phosphatase activity and some stem cell markers. However, such iPSC-like cells also proliferated rapidly, became neoplastic, and potentiated cell malignancy at a later stage in SCID mice. This study suggests that medulloblastoma cells can be reprogrammed successfully by JDP2 and OCT4 to become iPSC-like cells. These cells will be helpful for studying the generation of cancer stem cells and ROS homeostasis.

  13. Toxico-genomics of uranium-induced cell stress

    Energy Technology Data Exchange (ETDEWEB)

    Prat, O.; Berenguer, F.; Malard, V.; Quemeneur, V. [CEA Centre de Marcoule (DSV/DIEP/SBTN), 30 - Bagnols-sur-Ceze (France)

    2006-07-01

    The possibility of exposure of workers or population to materials originating from nuclear fuel process is a major concern worldwide. The radiological hazards have been the matter of intensive research for decades, and are consequently well understood. However, the chemical toxicity of most compounds originating from the nuclear industry certainly requires further research. In this respect, uranium is an interesting model since, due to its very long half-life, it is not considered as a major radiological hazard. At large concentrations, it induces harmful effects on human health, at the level of the respiratory system in case of inhalation, of kidneys and bones after entering into the blood-stream (Bleise et al. 2003). The kidney functional regions most at risk to injury are the proximal tubule and, to a lesser extent, the glomerulus (Leggett 1989). However, the consequences of chronic uranium exposure at very low concentration are largely unknown. In particular, the conservation of response mechanisms and/or adaptative mechanisms at such low levels are still to be demonstrated. The use of mics methodologies in the pharmaceutical industry has demonstrated its tremendous potential and allowed great progress to be made both in the understanding of the pathogenesis and in the design of novel treatments. Today, these methods invest the field of toxicology by measuring global changes in biological samples exposed to toxic agents (Hamadeh et al. 2002). This approach pursues three goals: (i) the improvement of the knowledge of mechanisms ruling toxicity, (ii) the research of a signature of each toxicant i.e. a minimal number of genes or proteins able to distinguish between an exposed state and a normal state in a biological system, (iii) the research of proteins as early bio-markers of effect. With these goals in mind, we used transcriptomics and proteomics to analyze human cultured cells exposed to uranyl containing media. To identify robust targets, we compared several

  14. Involvement of Endoplasmic Reticulum Stress, Autophagy, and Apoptosis in Advanced Glycation End Products-Induced Glomerular Mesangial Cell Injury

    Science.gov (United States)

    Chiang, Chih-Kang; Wang, Ching-Chia; Lu, Tien-Fong; Huang, Kuo-How; Sheu, Meei-Ling; Liu, Shing-Hwa; Hung, Kuan-Yu

    2016-01-01

    Advanced glycation end-products (AGEs)-induced mesangial cell death is one of major causes of glomerulus dysfunction in diabetic nephropathy. Both endoplasmic reticulum (ER) stress and autophagy are adaptive responses in cells under environmental stress and participate in the renal diseases. The role of ER stress and autophagy in AGEs-induced mesangial cell death is still unclear. Here, we investigated the effect and mechanism of AGEs on glomerular mesangial cells. AGEs dose-dependently decreased mesangial cell viability and induced cell apoptosis. AGEs also induced ER stress signals in a time- and dose-dependent manner. Inhibition of ER stress with 4-phenylbutyric acid effectively inhibited the activation of eIF2α and CHOP signals and reversed AGEs-induced cell apoptosis. AGEs also activated LC-3 cleavage, increased Atg5 expression, and decreased p62 expression, which indicated the autophagy induction in mesangial cells. Inhibition of autophagy by Atg5 siRNAs transfection aggravated AGEs-induced mesangial cell apoptosis. Moreover, ER stress inhibition by 4-phenylbutyric acid significantly reversed AGEs-induced autophagy, but autophagy inhibition did not influence the AGEs-induced ER stress-related signals activation. These results suggest that AGEs induce mesangial cell apoptosis via an ER stress-triggered signaling pathway. Atg5-dependent autophagy plays a protective role. These findings may offer a new strategy against AGEs toxicity in the kidney. PMID:27665710

  15. Oxidative Stress Induces Endothelial Cell Senescence via Downregulation of Sirt6

    Directory of Open Access Journals (Sweden)

    Rong Liu

    2014-01-01

    Full Text Available Accumulating evidence has shown that diabetes accelerates aging and endothelial cell senescence is involved in the pathogenesis of diabetic vascular complications, including diabetic retinopathy. Oxidative stress is recognized as a key factor in the induction of endothelial senescence and diabetic retinopathy. However, specific mechanisms involved in oxidative stress-induced endothelial senescence have not been elucidated. We hypothesized that Sirt6, which is a nuclear, chromatin-bound protein critically involved in many pathophysiologic processes such as aging and inflammation, may have a role in oxidative stress-induced vascular cell senescence. Measurement of Sirt6 expression in human endothelial cells revealed that H2O2 treatment significantly reduced Sirt6 protein. The loss of Sirt6 was associated with an induction of a senescence phenotype in endothelial cells, including decreased cell growth, proliferation and angiogenic ability, and increased expression of senescence-associated β-galactosidase activity. Additionally, H2O2 treatment reduced eNOS expression, enhanced p21 expression, and dephosphorylated (activated retinoblastoma (Rb protein. All of these alternations were attenuated by overexpression of Sirt6, while partial knockdown of Sirt6 expression by siRNA mimicked the effect of H2O2. In conclusion, these results suggest that Sirt6 is a critical regulator of endothelial senescence and oxidative stress-induced downregulation of Sirt6 is likely involved in the pathogenesis of diabetic retinopathy.

  16. Role of endoplasmic reticulum (ER) stress in cocaine-induced microglial cell death.

    Science.gov (United States)

    Costa, Blaise Mathias; Yao, Honghong; Yang, Lu; Buch, Shilpa

    2013-06-01

    While it has been well-documented that drugs of abuse such as cocaine can enhance progression of human immunodeficiency virus (HIV)-associated neuropathological disorders, the underlying mechanisms mediating these effects remain poorly understood. The present study was undertaken to examine the effects of cocaine on microglial viability. Herein we demonstrate that exposure of microglial cell line-BV2 or rat primary microglia to exogenous cocaine resulted in decreased cell viability as determined by MTS and TUNEL assays. Microglial toxicity of cocaine was accompanied by an increase in the expression of cleaved caspase-3 as demonstrated by western blot assays. Furthermore, increased microglial toxicity was also associated with a concomitant increase in the production of intracellular reactive oxygen species, an effect that was ameliorated in cells pretreated with NADPH oxidase inhibitor apocynin, thus emphasizing the role of oxidative stress in this process. A novel finding of this study was the involvement of endoplasmic reticulum (ER) signaling mediators such as PERK, Elf2α, and CHOP, which were up regulated in cells exposed to cocaine. Reciprocally, blocking CHOP expression using siRNA ameliorated cocaine-mediated cell death. In conclusion these findings underscore the importance of ER stress in modulating cocaine induced microglial toxicity. Understanding the link between ER stress, oxidative stress and apoptosis could lead to the development of therapeutic strategies targeting cocaine-mediated microglial death/dysfunction. PMID:23404095

  17. Vitamin E δ-tocotrienol triggers endoplasmic reticulum stress-mediated apoptosis in human melanoma cells.

    Science.gov (United States)

    Montagnani Marelli, Marina; Marzagalli, Monica; Moretti, Roberta M; Beretta, Giangiacomo; Casati, Lavinia; Comitato, Raffaella; Gravina, Giovanni L; Festuccia, Claudio; Limonta, Patrizia

    2016-01-01

    Malignant melanoma is the leading cause of death from skin cancer. Drug toxicity and resistance represent a serious challange for melanoma treatments. Evidence demonstrates that natural compounds may play a crucial role in cancer prevention, growth and progression. Vitamin E tocotrienols (TT) were shown to possess antitumor activity. Here, we analyzed the effects of δ-TT on melanoma cell growth and the involvement of the endoplasmic reticulum (ER) stress in this activity. The experiments were performed on human melanoma cell lines, BLM and A375. δ-TT exerted a significant proapoptotic effect on both cell lines, involving the intrinsic apoptosis pathway; importantly, this compound did not affect the viability of normal human melanocytes. In melanoma cells, δ-TT exerted its antitumor effect through activation of the PERK/p-eIF2α/ATF4/CHOP, IRE1α and caspase-4 ER stress-related branches. Salubrinal, an inhibitor of the ER stress, counteracted the cytotoxic activity of δ-TT. In vivo experiments performed in nude mice bearing A375 xenografts evidenced that δ-TT reduces tumor volume and tumor mass; importantly, tumor progression was significantly delayed by δ-TT treatment. In conclusion, δ-TT exerts a proapoptotic activity on melanoma cells, through activation of the ER stress-related pathways. δ-TT might represent an effective option for novel chemopreventive/therapeutic strategies for melanoma. PMID:27461002

  18. Dexamethasone protects airway epithelial cell line NCI-H292 against lipopolysaccharide induced endoplasmic reticulum stress and apoptosis

    Institute of Scientific and Technical Information of China (English)

    SHANG Yan; WANG Fang; BAI Chong; HUANG Yi; ZHAO Li-jun; YAO Xiao-peng; LI Qiang; SUN Shu-han

    2011-01-01

    Background Endoplasmic reticulum (ER) stress and ER stress-mediated apoptosis were reported to be involved in the pathogenesis of several diseases. In a recent study, it was reported that the ER stress pathway was activated in the lungs of lipopolysaccharide (LPS)-treated mice. It was also found that the C/EBP homologous protein (CHOP), an apoptosis-related molecule, played a key role in LPS-induced lung damage. The aim of this study was to verify whether LPS could activate the ER stress response in airway epithelial cells and which molecule was involved in the pathway.This study was also aimed at finding new reagents to protect the airway epithelial cells during LPS injury.Methods ER stress markers were observed in LPS-incubated NCI-H292 cells. SiRNA-MUC5AC was transfected into NCI-H292 cells. The effects of dexamethasone and erythromycin were observed in LPS-induced NCI-H292 cells.Results LPS incubation increased the expression of ER stress markers at the protein and mRNA levels. The knockout of MUC5AC in cells attenuated the increase in ER stress markers after incubation with LPS. Dexamethasone and erythromycin decreased caspase-3 activity in LPS-induced NCI-H292 cells.Conclusions LPS may activate ER stress through the overexpression of MUC5AC. Dexamethasone may protect human airway epithelial cells against ER stress-related apoptosis by attenuating the overload of MUC5AC.

  19. FUNCTION OF MALATDEHYDROGENASE COMPLEX OF MAIZE MESOPHYLL AND BUNDLE SHEATH CELLS UNDER SALT STRESS CONDITION

    Directory of Open Access Journals (Sweden)

    Еprintsev А.Т.

    2006-12-01

    Full Text Available Salt-induced changes in malatdehydrogenase system activity make the essential contribution to cell adaptation to stress condition. The enzyme systems of C4-plants are most interesting due to their ability for adaptation to environment conditions. The role of separate components of malatdehydrogenase complex of mesophyll and bundle sheath cells of corn in formation of adaptive reaction in stressful conditions is investigated in presented work.The activation of all enzymes of malatdehydrogenase system and the subsequent decrease in their activity was observed in mesophyll durring the first stage of adaptation to salt influence. In bundle sheath cells such parameters are differed from control less essentially. Fast accumulation of piruvate in cells and malate in both investigated tissues was induced. The further salinity led to falling of concentration this intermediate. The concentration of piruvate was below control level, and it was raised by the end of an exposition.The results show that sodium chloride causes induction of Krebs-cycle in mesophyll and bundle sheath cells of corn and intensification of Hatch-Slack cycle. The described differences in function malatdehydrogenase systems of mesophyll and bundle sheath cells of leaves of corn under salinity mainly consist of the activity of enzymes of a studied complex in bundle sheath cells is subject to the minimal changes in comparison with mesophyll. Role of this enzymesystem in mechanisms of adaptive reaction of various tissues of corn to salt stress is discussed.

  20. The Lcn2-engineered HEK-293 cells show senescence under stressful condition

    Directory of Open Access Journals (Sweden)

    Bahareh Bahmani

    2015-05-01

    Full Text Available Objective(s: Lipocalin2 (Lcn2 gene is highly expressed in response to various types of cellular stresses. The precise role of Lcn2 has not been fully understood yet. However, it plays a key role in controlling vital cellular processes such as proliferation, apoptosis and metabolism. Recently it was shown that Lcn2 decreases senescence and increases proliferation of mesenchymal stem cells (MSC with finite life span under either normal or oxidative stress conditions. However, Lcn2 effects on immortal cell line with infinite proliferation are not defined completely.  Materials and Material and Methods: HEK-293 cells were transfected with recombinant pcDNA3.1 containing Lcn2 fragment (pcDNA3.1-Lcn2. Expression of lipocalin2 in transfected cells was evaluated by RT-PCR, real time RT-PCR, and ELISA. Different cell groups were treated with H2O2 and WST-1 assay was performed to determine their proliferation rate. Senescence was studied by β-galactosidase and gimsa staining methods as well as evaluation of the expression of senescence-related genes by real time RT-PCR. Results: Lcn2 increased cell proliferation under normal culture condition, while the proliferation slightly decreased under oxidative stress.  This decrease was further found to be attributed to senescence. Conclusion: Our findings indicated that under harmful conditions, Lcn2 gene is responsible for the regulation of cell survival through senescence.

  1. Mitochondrial aldehyde dehydrogenase 2 protects gastric mucosa cells against DNA damage caused by oxidative stress.

    Science.gov (United States)

    Duan, Yantao; Gao, Yaohui; Zhang, Jun; Chen, Yinan; Jiang, Yannan; Ji, Jun; Zhang, Jianian; Chen, Xuehua; Yang, Qiumeng; Su, Liping; Zhang, Jun; Liu, Bingya; Zhu, Zhenggang; Wang, Lishun; Yu, Yingyan

    2016-04-01

    Mitochondrial aldehyde dehydrogenase 2 (ALDH2) is a member of the aldehyde dehydrogenase superfamily and is involved with the metabolic processing of aldehydes. ALDH2 plays a cytoprotective role by removing aldehydes produced during normal metabolism. We examined the cytoprotective role of ALDH2 specifically in gastric mucosa cells. Overexpression of ALDH2 increased the viability of gastric mucosa cells treated with H2O2, while knockdown of ALDH2 had an opposite effect. Moreover, overexpression of ALDH2 protected gastric mucosa cells against oxidative stress-induced apoptosis as determined by flow cytometry, Hoechst 33342, and TUNEL assays. Consistently, ALDH2 knockdown had an opposite effect. Additionally, DNA damage was ameliorated in ALDH2-overexpressing gastric mucosa cells treated with H2O2. We further identified that this cytoprotective role of ALDH2 was mediated by metabolism of 4-hydroxynonenal (4-HNE). Consistently, 4-HNE mimicked the oxidative stress induced by H2O2 in gastric mucosa cells. Treatment with 4-HNE increased levels of DNA damage in ALDH2-knockdown GES-1 cells, while overexpression of ALDH2 decreased 4-HNE-induced DNA damage. These findings suggest that ALDH2 can protect gastric mucosa cells against DNA damage caused by oxidative stress by reducing levels of 4-HNE.

  2. Psychological Stress-Derived Prolactin Modulates Occludin Expression in Vaginal Epithelial Cells to Compromise Barrier Function

    Directory of Open Access Journals (Sweden)

    Xueyan Li

    2015-08-01

    Full Text Available Background/Aims: The causative factors of the vaginitis are not fully understood yet. Epithelial barrier dysfunction plays a critical role in the pathogenesis of vaginitis. This study aims to investigate the role of prolactin (PRL in the causing the vaginal epithelial barrier dysfunction. Methods: Adult rats were treated with water-avoid-stress. The serum levels of PRL were determined by ELISA. T84 cell (T84 cells; a vaginal epithelial cell line monolayers were prepared to be used assessing the epithelial barrier functions. The expression of occludin in T84 cells was assessed by Chromatin immunoprecipitation assay, methylation specifIc PCR, real time quantitative RT-PCR and Western blotting. Results: The results showed that psychological stress markedly increased the serum levels of PRL in the rat vaginal epithelia. Exposure of T84 cells to PRL in the culture markedly increased the phosphorylation of STAT3 and suppressed the expression of occludin in the cells; the transepithelial electric resistance was decreased and the permeability to a macromolecular tracer was increased in the T84 monolayers, which was mimicked by blocking STAT3, or abolished by over expression of occludin in the epithelial cells. Conclusions: Psychological stress-derived PRL induces vaginal epithelial barrier dysfunction by inhibiting the expression of occludin.

  3. Activation of sensory nerves participates in stress-induced histamine release from mast cells in rats.

    Science.gov (United States)

    Huang, Z L; Mochizuki, T; Watanabe, H; Maeyama, K

    1999-08-01

    To elucidate the mechanism by which stress induces rapid histamine release from mast cells, Wistar rats, pretreated as neonates with capsaicin, were subjected to immobilization stress for 2 h, and histamine release was measured in paws of anesthetized rats by using in vivo microdialysis after activation of sensory nerves by electrical or chemical stimulation. Immobilization stress studies indicated that in control rats stress induced a 2.7-fold increase in the level of plasma histamine compared to that in freely moving rats. Whereas pretreatment with capsaicin significantly decreased stress-induced elevation of plasma histamine. Microdialysis studies showed that electrical stimulation of the sciatic nerve resulted in a 4-fold increase of histamine release in rat paws. However, this increase was significantly inhibited in rats pretreated with capsaicin. Furthermore, injection of capsaicin into rat paw significantly increased histamine release in a dose-dependent manner. These results suggest that activation of sensory nerves participates in stress-induced histamine release from mast cells. PMID:10462124

  4. Natural resistance to ascorbic acid induced oxidative stress is mainly mediated by catalase activity in human cancer cells and catalase-silencing sensitizes to oxidative stress

    Directory of Open Access Journals (Sweden)

    Klingelhoeffer Christoph

    2012-05-01

    Full Text Available Abstract Background Ascorbic acid demonstrates a cytotoxic effect by generating hydrogen peroxide, a reactive oxygen species (ROS involved in oxidative cell stress. A panel of eleven human cancer cell lines, glioblastoma and carcinoma, were exposed to serial dilutions of ascorbic acid (5-100 mmol/L. The purpose of this study was to analyse the impact of catalase, an important hydrogen peroxide-detoxifying enzyme, on the resistance of cancer cells to ascorbic acid mediated oxidative stress. Methods Effective concentration (EC50 values, which indicate the concentration of ascorbic acid that reduced the number of viable cells by 50%, were detected with the crystal violet assay. The level of intracellular catalase protein and enzyme activity was determined. Expression of catalase was silenced by catalase-specific short hairpin RNA (sh-RNA in BT-20 breast carcinoma cells. Oxidative cell stress induced apoptosis was measured by a caspase luminescent assay. Results The tested human cancer cell lines demonstrated obvious differences in their resistance to ascorbic acid mediated oxidative cell stress. Forty-five percent of the cell lines had an EC50 > 20 mmol/L and fifty-five percent had an EC50 50 of 2.6–5.5 mmol/L, glioblastoma cells were the most susceptible cancer cell lines analysed in this study. A correlation between catalase activity and the susceptibility to ascorbic acid was observed. To study the possible protective role of catalase on the resistance of cancer cells to oxidative cell stress, the expression of catalase in the breast carcinoma cell line BT-20, which cells were highly resistant to the exposure to ascorbic acid (EC50: 94,9 mmol/L, was silenced with specific sh-RNA. The effect was that catalase-silenced BT-20 cells (BT-20 KD-CAT became more susceptible to high concentrations of ascorbic acid (50 and 100 mmol/L. Conclusions Fifty-five percent of the human cancer cell lines tested were unable to protect themselves

  5. Dexamethasone-Induced Oxidative Stress Enhances Myeloma Cell Radiosensitization While Sparing Normal Bone Marrow Hematopoiesis

    Directory of Open Access Journals (Sweden)

    Soumen Bera

    2010-12-01

    Full Text Available Dexamethasone (Dex and radiation therapy are established modalities in multiple myeloma. In this study, we propose a novel combination of Dex plus radiation that shows superior clonogenic cell killing and apoptosis of myeloma cells and selectively eliminates myeloma cells when cocultured with bone marrow stromal cells (BMSCs. Dex was found to inhibit the release of interleukin-6 from irradiated BMSCs, which is an established myeloma cell proproliferative cytokine. In 5TGM1 model, the combination of Dex with skeletal targeted radiotherapy (153-Sm-EDTMP prolonged median survival time and inhibited radiation-induced myelosuppression. A two-cycle treatment of Dex plus 153-Sm-EDTMP was well tolerated and further improved median survival time. Mechanistically, Dex increased superoxide and hydrogen peroxide production and augmented radiation-induced oxidative stress and cell death of myeloma cells. In contrast, Dex inhibited radiation-induced increase in pro-oxidant levels and enhanced the clonogenic survival in normal hematopoietic stem and progenitor cells. Treatment with either N-acetylcysteine or the combination of polyethylene glycol (PEG-conjugated copper, zinc-superoxide dismutase, and PEG-catalase significantly protected myeloma cells from Dex-induced clonogenic death. Overall, these results demonstrate that Dex in combination with radiotherapy enhances the killing of myeloma cells while protecting normal bone marrow hematopoiesis through a mechanism that involves selective increases in oxidative stress.

  6. The Arctic Alzheimer mutation enhances sensitivity to toxic stress in human neuroblastoma cells

    DEFF Research Database (Denmark)

    Sennvik, Kristina; Nilsberth, Camilla; Stenh, Charlotte;

    2002-01-01

    The E693G (Arctic) mutation of the amyloid precursor protein was recently found to lead to early-onset Alzheimer's disease in a Swedish family. In the present study, we report that the Arctic mutation decreases cell viability in human neuroblastoma cells. The cell viability, as measured by the MTT...... their secretion of beta-secretase cleaved amyloid precursor protein. The enhanced sensitivity to toxic stress in cells with the Arctic mutation most likely contributes to the pathogenic pathway leading to Alzheimer's disease....

  7. Prediction of matrix-to-cell stress transfer in heart valve tissues.

    Science.gov (United States)

    Huang, Siyao; Huang, Hsiao-Ying Shadow

    2015-01-01

    Non-linear and anisotropic heart valve leaflet tissue mechanics manifest principally from the stratification, orientation, and inhomogeneity of their collagenous microstructures. Disturbance of the native collagen fiber network has clear consequences for valve and leaflet tissue mechanics and presumably, by virtue of their intimate embedment, on the valvular interstitial cell stress-strain state and concomitant phenotype. In the current study, a set of virtual biaxial stretch experiments were conducted on porcine pulmonary valve leaflet tissue photomicrographs via an image-based finite element approach. Stress distribution evolution during diastolic valve closure was predicted at both the tissue and cellular levels. Orthotropic material properties consistent with distinct stages of diastolic loading were applied. Virtual experiments predicted tissue- and cellular-level stress fields, providing insight into how matrix-to-cell stress transfer may be influenced by the inhomogeneous collagen fiber architecture, tissue anisotropic material properties, and the cellular distribution within the leaflet tissue. To the best of the authors' knowledge, this is the first study reporting on the evolution of stress fields at both the tissue and cellular levels in valvular tissue and thus contributes toward refining our collective understanding of valvular tissue micromechanics while providing a computational tool enabling the further study of valvular cell-matrix interactions.

  8. Differential importance of trehalose in stress resistance in fermenting and nonfermenting Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Van Dijck, P; Colavizza, D; Smet, P; Thevelein, J M

    1995-01-01

    The trehalose content in laboratory and industrial baker's yeast is widely believed to be a major determinant of stress resistance. Fresh and dried baker's yeast is cultured to obtain a trehalose content of more than 10% of the dry weight. Initiation of fermentation, e.g., during dough preparation, is associated with a rapid loss of stress resistance and a rapid mobilization of trehalose. Using specific Saccharomyces cerevisiae mutants affected in trehalose metabolism, we confirm the correlation between trehalose content and stress resistance but only in the absence of fermentation. We demonstrate that both phenomena can be dissociated clearly once the cells initiate fermentation. This was accomplished both for cells with moderate trehalose levels grown under laboratory conditions and for cells with trehalose contents higher than 10% obtained under pilot-scale conditions. Retention of a high trehalose level during fermentation also does not prevent the loss of fermentation capacity during preparation of frozen doughs. Although higher trehalose levels are always correlated with higher stress resistance before the addition of fermentable sugar, our results show that the initiation of fermentation causes the disappearance of any other factor(s) required for the maintenance of stress resistance, even in the presence of a high trehalose content. PMID:7887593

  9. Hypoxic stress up-regulates Kir2.1 expression and facilitates cell proliferation in brain capillary endothelial cells.

    Science.gov (United States)

    Yamamura, Hideto; Suzuki, Yoshiaki; Yamamura, Hisao; Asai, Kiyofumi; Imaizumi, Yuji

    2016-08-01

    The blood-brain barrier (BBB) is mainly composed of brain capillary endothelial cells (BCECs), astrocytes and pericytes. Brain ischemia causes hypoxic encephalopathy and damages BBB. However, it remains still unclear how hypoxia affects BCECs. In the present study, t-BBEC117 cells, an immortalized bovine brain endothelial cell line, were cultured under hypoxic conditions at 4-5% oxygen for 72 h. This hypoxic stress caused hyperpolarization of resting membrane potential. Patch-clamp recordings revealed a marked increase in Ba(2+)-sensitive inward rectifier K(+) current in t-BBEC117 cells after hypoxic culture. Western blot and real-time PCR analyses showed that Kir2.1 expression was significantly up-regulated at protein level but not at mRNA level after the hypoxic culture. Ca(2+) imaging study revealed that the hypoxic stress enhanced store-operated Ca(2+) (SOC) entry, which was significantly reduced in the presence of 100 μM Ba(2+). On the other hand, the expression of SOC channels such as Orai1, Orai2, and transient receptor potential channels was not affected by hypoxic stress. MTT assay showed that the hypoxic stress significantly enhanced t-BBEC117 cell proliferation, which was inhibited by approximately 60% in the presence of 100 μM Ba(2+). We first show here that moderate cellular stress by cultivation under hypoxic conditions hyperpolarizes membrane potential via the up-regulation of functional Kir2.1 expression and presumably enhances Ca(2+) entry, resulting in the facilitation of BCEC proliferation. These findings suggest potential roles of Kir2.1 expression in functional changes of BCECs in BBB following ischemia. PMID:27235552

  10. Nanoparticle induced oxidative stress in cancer cells: adding new pieces to an incomplete jigsaw puzzle.

    Science.gov (United States)

    Nogueira, Daniele Rubert; Rolim, Clarice M Bueno; Farooqi, Ammad Ahmad

    2014-01-01

    Nanotechnology is an emerging field with many promising applications in drug delivery systems. Because of outstanding developments in this field, rapidly increasing research is directed to the development of nanocarriers that may enhance the availability of drugs to the target sites. Substantial fraction of information has been added into the existing scientific literature focusing on the fact that nanoparticles usually generate reactive oxygen species to a greater extent than micro-sized particles. It is worth mentioning that oxidative stress regulates an array of cell signaling cascades that resulted in cancer cell damage. Accumulating experimental evidence over the years has shown that wide-ranging biological mechanisms are triggered by these NPs in cultured cells due to the unique properties of engineered nanoparticles. In this review, we have attempted to provide an overview of the signaling cascades that are activated by oxidative stress in cancer cells in response to different kinds of nanomaterials, including quantum dots, metallic and polymeric nanoparticles.

  11. An investigation of the influence of cell topography on epithelial mechanical stresses during pulmonary airway reopening

    Science.gov (United States)

    Jacob, A. M.; Gaver, D. P.

    2005-03-01

    The goal of this study is to assess the local mechanical environment of the pulmonary epithelium in a computational model of airway reopening. To this end, the boundary element method (BEM) in conjunction with lubrication theory is implemented to assess the stationary-state behavior of a semi-infinite bubble traveling through a liquid-occluded parallel plate flow chamber lined with epithelial cells. The fluid occlusion is assumed to be Newtonian and inertia is neglected. The interactions between the microgeometry of the model airway's walls and the interfacial kinematics surrounding the bubble's tip result in a complex, spatially and temporally dependent stress distribution. The walls' nonplanar topography magnifies the normal and shear stresses and stress gradients. We find that decreasing the bubble's speed serves to increase the maximum normal stress and stress gradient but decrease the maximum shear stress and stress gradient. Our results give credence to the pressure-gradient-induced epithelial damage theory recently proposed by Bilek et al. [J. Appl. Physiol. 94, 770 (2003)] and Kay et al. [J. Appl. Physiol. 97, 269 (2004)]. We conclude that the amplified pressure gradients found in this study may be even more detrimental to the airway's cellular epithelium during airway reopening.

  12. Galectin-3 Determines Tumor Cell Adaptive Strategies in Stressed Tumor Microenvironments

    Science.gov (United States)

    Cardoso, Ana Carolina Ferreira; Andrade, Luciana Nogueira de Sousa; Bustos, Silvina Odete; Chammas, Roger

    2016-01-01

    Galectin-3 is a member of the β-galactoside-binding lectin family, whose expression is often dysregulated in cancers. While galectin-3 is usually an intracellular protein found in the nucleus and in the cytoplasm, under certain conditions, galectin-3 can be secreted by an yet unknown mechanism. Under stressing conditions (e.g., hypoxia and nutrient deprivation) galectin-3 is upregulated, through the activity of transcription factors, such as HIF-1α and NF-κB. Here, we review evidence that indicates a positive role for galectin-3 in MAPK family signal transduction, leading to cell proliferation and cell survival. Galectin-3 serves as a scaffold protein, which favors the spatial organization of signaling proteins as K-RAS. Upon secretion, extracellular galectin-3 interacts with a variety of cell surface glycoproteins, such as growth factor receptors, integrins, cadherins, and members of the Notch family, among other glycoproteins, besides different extracellular matrix molecules. Through its ability to oligomerize, galectin-3 forms lectin lattices that act as scaffolds that sustain the spatial organization of signaling receptors on the cell surface, dictating its maintenance on the plasma membrane or their endocytosis. Galectin-3 induces tumor cell, endothelial cell, and leukocyte migration, favoring either the exit of tumor cells from a stressed microenvironment or the entry of endothelial cells and leukocytes, such as monocytes/macrophages into the tumor organoid. Therefore, galectin-3 plays homeostatic roles in tumors, as (i) it favors tumor cell adaptation for survival in stressed conditions; (ii) upon secretion, galectin-3 induces tumor cell detachment and migration; and (iii) it attracts monocyte/macrophage and endothelial cells to the tumor mass, inducing both directly and indirectly the process of angiogenesis. The two latter activities are potentially targetable, and specific interventions may be designed to counteract the protumoral role of extracellular

  13. Galectin-3 Determines Tumor Cell Adaptive Strategies in Stressed Tumor Microenvironments.

    Science.gov (United States)

    Cardoso, Ana Carolina Ferreira; Andrade, Luciana Nogueira de Sousa; Bustos, Silvina Odete; Chammas, Roger

    2016-01-01

    Galectin-3 is a member of the β-galactoside-binding lectin family, whose expression is often dysregulated in cancers. While galectin-3 is usually an intracellular protein found in the nucleus and in the cytoplasm, under certain conditions, galectin-3 can be secreted by an yet unknown mechanism. Under stressing conditions (e.g., hypoxia and nutrient deprivation) galectin-3 is upregulated, through the activity of transcription factors, such as HIF-1α and NF-κB. Here, we review evidence that indicates a positive role for galectin-3 in MAPK family signal transduction, leading to cell proliferation and cell survival. Galectin-3 serves as a scaffold protein, which favors the spatial organization of signaling proteins as K-RAS. Upon secretion, extracellular galectin-3 interacts with a variety of cell surface glycoproteins, such as growth factor receptors, integrins, cadherins, and members of the Notch family, among other glycoproteins, besides different extracellular matrix molecules. Through its ability to oligomerize, galectin-3 forms lectin lattices that act as scaffolds that sustain the spatial organization of signaling receptors on the cell surface, dictating its maintenance on the plasma membrane or their endocytosis. Galectin-3 induces tumor cell, endothelial cell, and leukocyte migration, favoring either the exit of tumor cells from a stressed microenvironment or the entry of endothelial cells and leukocytes, such as monocytes/macrophages into the tumor organoid. Therefore, galectin-3 plays homeostatic roles in tumors, as (i) it favors tumor cell adaptation for survival in stressed conditions; (ii) upon secretion, galectin-3 induces tumor cell detachment and migration; and (iii) it attracts monocyte/macrophage and endothelial cells to the tumor mass, inducing both directly and indirectly the process of angiogenesis. The two latter activities are potentially targetable, and specific interventions may be designed to counteract the protumoral role of extracellular

  14. Stress-related hormone norepinephrine induces interleukin-6 expression in GES-1 cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, R.; Lin, Q.; Gao, H.B.; Zhang, P. [Department of Biochemistry and Molecular Cell Biology, School of Medicine, Shanghai Jiao Tong University, Shanghai, China, Department of Biochemistry and Molecular Cell Biology, School of Medicine, Shanghai Jiao Tong University, Shanghai (China)

    2014-02-17

    In the current literature, there is evidence that psychological factors can affect the incidence and progression of some cancers. Interleukin 6 (IL-6) is known to be elevated in individuals experiencing chronic stress and is also involved in oncogenesis and cancer progression. However, the precise mechanism of IL-6 induction by the stress-related hormone norepinephrine (NE) is not clear, and, furthermore, there are no reports about the effect of NE on IL-6 expression in gastric epithelial cells. In this study, we examined the effect of NE on IL-6 expression in immortalized human gastric epithelial cells (GES-1 cells). Using real-time PCR and enzyme-linked immunoassay, we demonstrated that NE can induce IL-6 mRNA and protein expression in GES-1 cells. The induction is through the β-adrenergic receptor-cAMP-protein kinase A pathway and mainly at the transcriptional level. Progressive 5′-deletions and site-directed mutagenesis of the parental construct show that, although activating-protein-1 (AP-1), cAMP-responsive element binding protein (CREB), CCAAT-enhancer binding protein-β (C/EBP-β), and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) binding sites are all required in the basal transcription of IL-6, only AP-1 and CREB binding sites in the IL-6 promoter are required in NE-induced IL-6 expression. The results suggest that chronic stress may increase IL-6 secretion of human gastric epithelial cells, at least in part, by the stress-associated hormone norepinephrine, and provides basic data on stress and gastric cancer progression.

  15. Stress-related hormone norepinephrine induces interleukin-6 expression in GES-1 cells

    Directory of Open Access Journals (Sweden)

    R. Yang

    2014-02-01

    Full Text Available In the current literature, there is evidence that psychological factors can affect the incidence and progression of some cancers. Interleukin 6 (IL-6 is known to be elevated in individuals experiencing chronic stress and is also involved in oncogenesis and cancer progression. However, the precise mechanism of IL-6 induction by the stress-related hormone norepinephrine (NE is not clear, and, furthermore, there are no reports about the effect of NE on IL-6 expression in gastric epithelial cells. In this study, we examined the effect of NE on IL-6 expression in immortalized human gastric epithelial cells (GES-1 cells. Using real-time PCR and enzyme-linked immunoassay, we demonstrated that NE can induce IL-6 mRNA and protein expression in GES-1 cells. The induction is through the β-adrenergic receptor-cAMP-protein kinase A pathway and mainly at the transcriptional level. Progressive 5′-deletions and site-directed mutagenesis of the parental construct show that, although activating-protein-1 (AP-1, cAMP-responsive element binding protein (CREB, CCAAT-enhancer binding protein-β (C/EBP-β, and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB binding sites are all required in the basal transcription of IL-6, only AP-1 and CREB binding sites in the IL-6 promoter are required in NE-induced IL-6 expression. The results suggest that chronic stress may increase IL-6 secretion of human gastric epithelial cells, at least in part, by the stress-associated hormone norepinephrine, and provides basic data on stress and gastric cancer progression.

  16. Genes and Gene Networks Involved in Sodium Fluoride-Elicited Cell Death Accompanying Endoplasmic Reticulum Stress in Oral Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Yoshiaki Tabuchi

    2014-05-01

    Full Text Available Here, to understand the molecular mechanisms underlying cell death induced by sodium fluoride (NaF, we analyzed gene expression patterns in rat oral epithelial ROE2 cells exposed to NaF using global-scale microarrays and bioinformatics tools. A relatively high concentration of NaF (2 mM induced cell death concomitant with decreases in mitochondrial membrane potential, chromatin condensation and caspase-3 activation. Using 980 probe sets, we identified 432 up-regulated and 548 down-regulated genes, that were differentially expressed by >2.5-fold in the cells treated with 2 mM of NaF and categorized them into 4 groups by K-means clustering. Ingenuity® pathway analysis revealed several gene networks from gene clusters. The gene networks Up-I and Up-II included many up-regulated genes that were mainly associated with the biological function of induction or prevention of cell death, respectively, such as Atf3, Ddit3 and Fos (for Up-I and Atf4 and Hspa5 (for Up-II. Interestingly, knockdown of Ddit3 and Hspa5 significantly increased and decreased the number of viable cells, respectively. Moreover, several endoplasmic reticulum (ER stress-related genes including, Ddit3, Atf4 and Hapa5, were observed in these gene networks. These findings will provide further insight into the molecular mechanisms of NaF-induced cell death accompanying ER stress in oral epithelial cells.

  17. Combination of fluid and solid mechanical stresses contribute to cell death and detachment in a microfluidic alveolar model.

    Science.gov (United States)

    Douville, Nicholas J; Zamankhan, Parsa; Tung, Yi-Chung; Li, Ran; Vaughan, Benjamin L; Tai, Cheng-Feng; White, Joshua; Christensen, Paul J; Grotberg, James B; Takayama, Shuichi

    2011-02-21

    Studies using this micro-system demonstrated significant morphological differences between alveolar epithelial cells (transformed human alveolar epithelial cell line, A549 and primary murine alveolar epithelial cells, AECs) exposed to combination of solid mechanical and surface-tension stresses (cyclic propagation of air-liquid interface and wall stretch) compared to cell populations exposed solely to cyclic stretch. We have also measured significant differences in both cell death and cell detachment rates in cell monolayers experiencing combination of stresses. This research describes new tools for studying the combined effects of fluid mechanical and solid mechanical stress on alveolar cells. It also highlights the role that surface tension forces may play in the development of clinical pathology, especially under conditions of surfactant dysfunction. The results support the need for further research and improved understanding on techniques to reduce and eliminate fluid stresses in clinical settings. PMID:21152526

  18. Emerging roles of extracellular vesicles in the adaptive response of tumour cells to microenvironmental stress

    Directory of Open Access Journals (Sweden)

    Paulina Kucharzewska

    2013-03-01

    Full Text Available Cells are constantly subjected to various types of endogenous and exogenous stressful stimuli, which can cause serious and even permanent damage. The ability of a cell to sense and adapt to environmental alterations is thus vital to maintain tissue homeostasis during development and adult life. Here, we review some of the major phenotypic characteristics of the hostile tumour microenvironment and the emerging roles of extracellular vesicles in these events.

  19. Prohibitin 1 modulates mitochondrial stress-related autophagy in human colonic epithelial cells.

    Directory of Open Access Journals (Sweden)

    Arwa S Kathiria

    Full Text Available INTRODUCTION: Autophagy is an adaptive response to extracellular and intracellular stress by which cytoplasmic components and organelles, including damaged mitochondria, are degraded to promote cell survival and restore cell homeostasis. Certain genes involved in autophagy confer susceptibility to Crohn's disease. Reactive oxygen species and pro-inflammatory cytokines such as tumor necrosis factor α (TNFα, both of which are increased during active inflammatory bowel disease, promote cellular injury and autophagy via mitochondrial damage. Prohibitin (PHB, which plays a role in maintaining normal mitochondrial respiratory function, is decreased during active inflammatory bowel disease. Restoration of colonic epithelial PHB expression protects mice from experimental colitis and combats oxidative stress. In this study, we investigated the potential role of PHB in modulating mitochondrial stress-related autophagy in intestinal epithelial cells. METHODS: We measured autophagy activation in response to knockdown of PHB expression by RNA interference in Caco2-BBE and HCT116 WT and p53 null cells. The effect of exogenous PHB expression on TNFα- and IFNγ-induced autophagy was assessed. Autophagy was inhibited using Bafilomycin A(1 or siATG16L1 during PHB knockdown and the affect on intracellular oxidative stress, mitochondrial membrane potential, and cell viability were determined. The requirement of intracellular ROS in siPHB-induced autophagy was assessed using the ROS scavenger N-acetyl-L-cysteine. RESULTS: TNFα and IFNγ-induced autophagy inversely correlated with PHB protein expression. Exogenous PHB expression reduced basal autophagy and TNFα-induced autophagy. Gene silencing of PHB in epithelial cells induces mitochondrial autophagy via increased intracellular ROS. Inhibition of autophagy during PHB knockdown exacerbates mitochondrial depolarization and reduces cell viability. CONCLUSIONS: Decreased PHB levels coupled with dysfunctional

  20. Modulation of Apoptosis Pathways by Oxidative Stress and Autophagy in β Cells

    Directory of Open Access Journals (Sweden)

    Maorong Wang

    2012-01-01

    Full Text Available Human islets isolated for transplantation are exposed to multiple stresses including oxidative stress and hypoxia resulting in significant loss of functional β cell mass. In this study we examined the modulation of apoptosis pathway genes in islets exposed to hydrogen peroxide, peroxynitrite, hypoxia, and cytokines. We observed parallel induction of pro- and antiapoptotic pathways and identified several novel genes including BFAR, CARD8, BNIP3, and CIDE-A. As BNIP3 is an inducer of autophagy, we examined this pathway in MIN6 cells, a mouse beta cell line and in human islets. Culture of MIN6 cells under low serum conditions increased the levels of several proteins in autophagy pathway, including ATG4, Beclin 1, LAMP-2, and UVRAG. Amino acid deprivation led to induction of autophagy in human islets. Preconditioning of islets with inducers of autophagy protected them from hypoxia-induced apoptosis. However, induction of autophagy during hypoxia exacerbated apoptotic cell death. ER stress led to induction of autophagy and apoptosis in β cells. Overexpression of MnSOD, an enzyme that scavenges free radicals, resulted in protection of MIN6 cells from cytokine-induced apoptosis. Ceramide, a mediator of cytokine-induced injury, reduced the active phosphorylated form of Akt and downregulated the promoter activity of the antiapoptotic gene bcl-2. Furthermore, cytokine-stimulated JNK pathway downregulated the bcl-2 promoter activity which was reversed by preincubation with SP600125, a JNK inhibitor. Our findings suggest that β cell apoptosis by multiple stresses in islets isolated for transplantation is the result of orchestrated gene expression in apoptosis pathway.

  1. Effect of stress on the membrane capacitance of the auditory outer hair cell.

    OpenAIRE

    Iwasa, K H

    1993-01-01

    The membrane capacitance of the outer hair cell, which has unique membrane potential-dependent motility, was monitored during application of membrane tension. It was found that the membrane capacitance of the cell decreased when stress was applied to the membrane. This result is the opposite of stretching the lipid bilayer in the plasma membrane. It thus indicates the importance of some other capacitance component that decreases on stretching. It has been known that charge movement across the...

  2. Aryl hydrocarbon receptor protects lung adenocarcinoma cells against cigarette sidestream smoke particulates-induced oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Ya-Hsin [Graduate Institute of Basic Medical Science, School of Medicine, China Medical University, Taichung 40402, Taiwan, ROC (China); Huang, Su-Chin; Lin, Chun-Ju; Cheng, Li-Chuan [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan, ROC (China); Li, Lih-Ann, E-mail: lihann@nhri.org.tw [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Zhunan, Miaoli 35053, Taiwan, ROC (China)

    2012-03-15

    Environmental cigarette smoke has been suggested to promote lung adenocarcinoma progression through aryl hydrocarbon receptor (AhR)-signaled metabolism. However, whether AhR facilitates metabolic activation or detoxification in exposed adenocarcinoma cells remains ambiguous. To address this question, we have modified the expression level of AhR in two human lung adenocarcinoma cell lines and examined their response to an extract of cigarette sidestream smoke particulates (CSSP). We found that overexpression of AhR in the CL1-5 cell line reduced CSSP-induced ROS production and oxidative DNA damage, whereas knockdown of AhR expression increased ROS level in CSSP-exposed H1355 cells. Oxidative stress sensor Nrf2 and its target gene NQO1 were insensitive to AhR expression level and CSSP treatment in human lung adenocarcinoma cells. In contrast, induction of AhR expression concurrently increased mRNA expression of xenobiotic-metabolizing genes CYP1B1, UGT1A8, and UGT1A10 in a ligand-independent manner. It appeared that AhR accelerated xenobiotic clearing and diminished associated oxidative stress by coordinate regulation of a set of phase I and II metabolizing genes. However, the AhR-signaled protection could not shield cells from constant oxidative stress. Prolonged exposure to high concentrations of CSSP induced G0/G1 cell cycle arrest via the p53–p21–Rb1 signaling pathway. Despite no effect on DNA repair rate, AhR facilitated the recovery of cells from growth arrest when CSSP exposure ended. AhR-overexpressing lung adenocarcinoma cells exhibited an increased anchorage-dependent and independent proliferation when recovery from exposure. In summary, our data demonstrated that AhR protected lung adenocarcinoma cells against CSSP-induced oxidative stress and promoted post-exposure clonogenicity. -- Highlights: ► AhR expression level influences cigarette sidestream smoke-induced ROS production. ► AhR reduces oxidative stress by coordinate regulation of

  3. Telomere dynamics in human mesenchymal stem cells after exposure to acute oxidative stress

    DEFF Research Database (Denmark)

    Harbo, M.; Koelvraa, S.; Serakinci, N.;

    2012-01-01

    A gradual shortening of telomeres due to replication can be measured using the standard telomere restriction fragments (TRF) assay and other methods by measuring the mean length of all the telomeres in a cell. In contrast, stress-induced telomere shortening, which is believed to be just...... due to the advantages of the newly developed Universal single telomere length assay (STELA), and we therefore believe that this method should be considered the method of choice when measuring the length of telomeres after exposure to oxidative stress. In order to test our hypothesis, cultured human...... estimated by senescence-associated beta-galactosidase staining. The exposure to acute oxidative stress resulted in an increased number of ultra-short telomeres, which correlated strongly with the percentage of senescent cells, whereas a correlation between mean telomere length and the percentage...

  4. Prenatal stress is a vulnerability factor for altered morphology and biological activity of microglia cells.

    Directory of Open Access Journals (Sweden)

    Joanna eŚlusarczyk

    2015-03-01

    Full Text Available Several lines of evidence suggest that the dysregulation of the immune system is an important factor in the development of depression. Microglia are the resident macrophages of the central nervous system and a key player in innate immunity of the brain. We hypothesized that prenatal stress (an animal model of depression as a priming factor could affect microglial cells and might lead to depressive-like disturbances in adult male rat offspring. We investigated the behavioral changes (sucrose preference test, Porsolt test, the expression of C1q and CD40 mRNA and the level of microglia (Iba1 positive in 3 month old control and prenatally stressed male offspring rats. In addition, we characterized the morphological and biochemical parameters of potentially harmful (NO, iNOS, IL-1β, IL-18, IL-6, TNF-α, CCL2, CXCL12, CCR2, CXCR4 and beneficial (IGF-1, BDNF phenotypes in cultures of microglia obtained from the cortices of 1-2 days old control and prenatally stressed pups. The adult prenatally stressed rats showed behavioral (anhedonic- and depression-like disturbances, enhanced expression of microglial activation markers and an increased number of Iba1-immunopositive cells in the hippocampus and frontal cortex. The morphology of glia was altered in cultures from prenatally stressed rats, as demonstrated by immunofluorescence microscopy. Moreover, in these cultures, we observed enhanced expression of CD40 and MHC II and release of pro-inflammatory cytokines, including IL-1β, IL-18, TNF-α and IL-6. Prenatal stress significantly up-regulated levels of the chemokines CCL2, CXCL12 and altered expression of their receptors, CCR2 and CXCR4 while IGF-1 production was suppressed in cultures of microglia from prenatally stressed rats.Our results suggest that prenatal stress may lead to excessive microglia activation and contribute to the behavioral changes observed in depression in adulthood.

  5. Cadmium induced oxidative stress in kidney epithelia cells

    DEFF Research Database (Denmark)

    Bjerregaard, Henning F.

    2007-01-01

    Cadmium (Cd) is an important industrial and environmental pollutant. In humans exposed to Cd via oral and/or pulmonary routes, the kidney is by far the primary organ affected adversely by Cd. It have been estimated that 7% of the human population may develop renal dysfunction from Cd exposure...... of generation of ROS in this pathway remains unclear.     The aim of the present study was to monitor, in real time, the rates of ROS generation to be able to directly determine their production dynamics in living cells in response to drugs. Initial studies were planed in to use 2,7-dichlorofluorescein...

  6. Suppression of natural killer cell activity by surgical stress in cancer patients and the underlying mechanisms.

    Directory of Open Access Journals (Sweden)

    Yoshihara,Hisashi

    1986-04-01

    Full Text Available The influence of surgical stress on the natural killer (NK activity of peripheral blood lymphocytes in patients with carcinoma of the lung or gastrointestinal system was studied. The peripheral blood lymphocytes of the patients showed a marked decrease in NK activity against K-562 cells as target cells 1-2 days after surgery. The activity remained lowered for 2 weeks after thoractomy and for 1 week after laparotomy. No appreciable suppression of NK activity was observed with normal human peripheral blood lymphocytes preincubated with postoperative patient sera. Peripheral blood mononuclear cells obtained postoperatively from patients lost NK activity after ultraviolet irradiation, without any detectable loss of viability. Such irradiated mononuclear cells showed inhibition of NK activity after a 24-hour preincubation with peripheral blood lymphocytes from normal subjects. Similar suppressive activity was demonstrable in a fraction of mononuclear cells with adhesiveness to plastic petri dishes, while non-adherent cells had no such activity. When added immediately to the cytotoxicity assay system without the 24-hour preincubation, patient mononuclear cells caused no inhibition of NK activity, whereas adherent cells from normal subjects enhanced NK activity. The findings seems to indicate that, following surgical stress, plastic dish-adherent peripheral blood mononuclear cells become deprived of NK helper activity and exert suppression, thus causing postoperative depression of NK activity.

  7. Oxidative stress plays a role in high glucose-induced activation of pancreatic stellate cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Gyeong Ryul; Lee, Esder; Chun, Hyun-Ji; Yoon, Kun-Ho; Ko, Seung-Hyun; Ahn, Yu-Bae; Song, Ki-Ho, E-mail: kihos@catholic.ac.kr

    2013-09-20

    Highlights: •High glucose increased production of reactive oxygen species in cultured pancreatic stellate cells. •High glucose facilitated the activation of these cells. •Antioxidant treatment attenuated high glucose-induced activation of these cells. -- Abstract: The activation of pancreatic stellate cells (PSCs) is thought to be a potential mechanism underlying islet fibrosis, which may contribute to progressive β-cell failure in type 2 diabetes. Recently, we demonstrated that antioxidants reduced islet fibrosis in an animal model of type 2 diabetes. However, there is no in vitro study demonstrating that high glucose itself can induce oxidative stress in PSCs. Thus, PSCs were isolated and cultured from Sprague Dawley rats, and treated with high glucose for 72 h. High glucose increased the production of reactive oxygen species. When treated with high glucose, freshly isolated PSCs exhibited myofibroblastic transformation. During early culture (passage 1), PSCs treated with high glucose contained an increased number of α-smooth muscle actin-positive cells. During late culture (passages 2–5), PSCs treated with high glucose exhibited increases in cell proliferation, the expression of fibronectin and connective tissue growth factor, release of interleukin-6, transforming growth factor-β and collagen, and cell migration. Finally, the treatment of PSCs with high glucose and antioxidants attenuated these changes. In conclusion, we demonstrated that high glucose increased oxidative stress in primary rat PSCs, thereby facilitating the activation of these cells, while antioxidant treatment attenuated high glucose-induced PSC activation.

  8. Oxidative stress plays a role in high glucose-induced activation of pancreatic stellate cells

    International Nuclear Information System (INIS)

    Highlights: •High glucose increased production of reactive oxygen species in cultured pancreatic stellate cells. •High glucose facilitated the activation of these cells. •Antioxidant treatment attenuated high glucose-induced activation of these cells. -- Abstract: The activation of pancreatic stellate cells (PSCs) is thought to be a potential mechanism underlying islet fibrosis, which may contribute to progressive β-cell failure in type 2 diabetes. Recently, we demonstrated that antioxidants reduced islet fibrosis in an animal model of type 2 diabetes. However, there is no in vitro study demonstrating that high glucose itself can induce oxidative stress in PSCs. Thus, PSCs were isolated and cultured from Sprague Dawley rats, and treated with high glucose for 72 h. High glucose increased the production of reactive oxygen species. When treated with high glucose, freshly isolated PSCs exhibited myofibroblastic transformation. During early culture (passage 1), PSCs treated with high glucose contained an increased number of α-smooth muscle actin-positive cells. During late culture (passages 2–5), PSCs treated with high glucose exhibited increases in cell proliferation, the expression of fibronectin and connective tissue growth factor, release of interleukin-6, transforming growth factor-β and collagen, and cell migration. Finally, the treatment of PSCs with high glucose and antioxidants attenuated these changes. In conclusion, we demonstrated that high glucose increased oxidative stress in primary rat PSCs, thereby facilitating the activation of these cells, while antioxidant treatment attenuated high glucose-induced PSC activation

  9. A multi-shear perfusion bioreactor for investigating shear stress effects in endothelial cell constructs.

    Science.gov (United States)

    Rotenberg, Menahem Y; Ruvinov, Emil; Armoza, Anna; Cohen, Smadar

    2012-08-01

    Tissue engineering research is increasingly relying on the use of advanced cultivation technologies that provide rigorously-controlled cell microenvironments. Herein, we describe the features of a micro-fabricated Multi-Shear Perfusion Bioreactor (MSPB) designed to deliver up to six different levels of physiologically-relevant shear stresses (1-13 dyne cm(-2)) to six cell constructs simultaneously, during a single run. To attain a homogeneous fluid flow within each construct, flow-distributing nets photo-etched with a set of openings for fluid flow were placed up- and down-stream from each construct. Human umbilical vein endothelial cells (HUVECs) seeded in alginate scaffolds within the MSPB and subjected to three different levels of shear stress for 24 h, responded accordingly by expressing three different levels of the membranal marker Intercellular Adhesion Molecule 1 (ICAM-1) and the phosphorylated endothelial nitric oxide synthetase (eNOS). A longer period of cultivation, 17 d, under two different levels of shear stress resulted in different lengths of cell sprouts within the constructs. Collectively, the HUVEC behaviour within the different constructs confirms the feasibility of using the MSPB system for simultaneously imposing different shear stress levels, and for validating the flow regime in the bioreactor vessel as assessed by the computational fluid dynamic (CFD) model. PMID:22622237

  10. Phenotypic and Transcriptomic Analyses of Mildly and Severely Salt-Stressed Bacillus cereus ATCC 14579 Cells

    NARCIS (Netherlands)

    Besten, den H.M.W.; Mols, J.M.; Moezelaar, R.; Zwietering, M.H.; Abee, T.

    2009-01-01

    Bacteria are able to cope with the challenges of a sudden increase in salinity by activating adaptation mechanisms. In this study, exponentially growing cells of the pathogen Bacillus cereus ATCC 14579 were exposed to both mild (2.5% [wt/vol] NaCl) and severe (5% [wt/vol] NaCl) salt stress condition

  11. Storage-induced increase in biomarkers of oxidative stress and inflammation in red blood cell components

    DEFF Research Database (Denmark)

    Kucukakin, B.; Kocak, Volkan; Lykkesfeldt, Jens;

    2011-01-01

    buffy-coat reduced red cells in SAG-M additive solution, by assessing biomarkers of oxidative and inflammatory stress during a storage period of 35 days. Study design and methods. Ten units of RBCs were stored for 35 days. Samples were collected from the units at storage days 1, 3, 7, 14, 21, 28 and 35...

  12. Calcium Homeostasis and ER Stress in Control of Autophagy in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Elżbieta Kania

    2015-01-01

    Full Text Available Autophagy is a basic catabolic process, serving as an internal engine during responses to various cellular stresses. As regards cancer, autophagy may play a tumor suppressive role by preserving cellular integrity during tumor development and by possible contribution to cell death. However, autophagy may also exert oncogenic effects by promoting tumor cell survival and preventing cell death, for example, upon anticancer treatment. The major factors influencing autophagy are Ca2+ homeostasis perturbation and starvation. Several Ca2+ channels like voltage-gated T- and L-type channels, IP3 receptors, or CRAC are involved in autophagy regulation. Glucose transporters, mainly from GLUT family, which are often upregulated in cancer, are also prominent targets for autophagy induction. Signals from both Ca2+ perturbations and glucose transport blockage might be integrated at UPR and ER stress activation. Molecular pathways such as IRE 1-JNK-Bcl-2, PERK-eIF2α-ATF4, or ATF6-XBP 1-ATG are related to autophagy induced through ER stress. Moreover ER molecular chaperones such as GRP78/BiP and transcription factors like CHOP participate in regulation of ER stress-mediated autophagy. Autophagy modulation might be promising in anticancer therapies; however, it is a context-dependent matter whether inhibition or activation of autophagy leads to tumor cell death.

  13. Paraoxonases 1, 2, and 3, oxidative stress, and macrophage foam cell formation during atherosclerosis development.

    Science.gov (United States)

    Aviram, Michael; Rosenblat, Mira

    2004-11-01

    Paraoxonases PON1 and PON3, which are both associated in serum with HDL, protect the serum lipids from oxidation, probably as a result of their ability to hydrolyze specific oxidized lipids. The activity of HDL-associated PON1 seems to involve an activity (phospholipase A2-like activity, peroxidase-like activity, lactonase activity) which produces LPC. To study the possible role of PON1 in macrophage foam cell formation and atherogenesis we used macrophages from control mice, from PON1 knockout mice, and from PON1 transgenic mice. Furthermore, we analyzed PON1-treated macrophages and PON1-transfected cells to demonstrate the contribution of PON1 to the attenuation of macrophage cholesterol and oxidized lipid accumulation and foam cell formation. PON1 was shown to inhibit cholesterol influx [by reducing the formation of oxidized LDL (Ox-LDL), increasing the breakdown of specific oxidized lipids in Ox-LDL, and decreasing macrophage uptake of Ox-LDL]. PON1 also inhibits cholesterol biosynthesis and stimulates HDL-mediated cholesterol efflux from macrophages. PON2 and PON3 protect against oxidative stress, with PON2 acting mainly at the cellular level. Whereas serum PON1 and PON3 were inactivated under oxidative stress, macrophage PON2 expression and activity were increased under oxidative stress, probably as a compensatory mechanism against oxidative stress. Intervention to increase the paraoxonases (cellular and humoral) by dietary or pharmacological means can reduce macrophage foam cell formation and attenuate atherosclerosis development. PMID:15454271

  14. Determining adaptive and adverse oxidative stress responses in human bronical epithelial cells exposed to zinc

    Science.gov (United States)

    Determining adaptive and adverse oxidative stress responses in human bronchial epithelial cells exposed to zincJenna M. Currier1,2, Wan-Yun Cheng1, Rory Conolly1, Brian N. Chorley1Zinc is a ubiquitous contaminant of ambient air that presents an oxidant challenge to the human lung...

  15. Protective Effect of Wheat Peptides against Indomethacin-Induced Oxidative Stress in IEC-6 Cells

    Directory of Open Access Journals (Sweden)

    Hong Yin

    2014-01-01

    Full Text Available Recent studies have demonstrated that wheat peptides protected rats against non-steroidal anti-inflammatory drugs-induced small intestinal epithelial cells damage, but the mechanism of action is unclear. In the present study, an indomethacin-induced oxidative stress model was used to investigate the effect of wheat peptides on the nuclear factor-κB(NF-κB-inducible nitric oxide synthase-nitric oxide signal pathway in intestinal epithelial cells-6 cells. IEC-6 cells were treated with wheat peptides (0, 125, 500 and 2000 mg/L for 24 h, followed by 90 mg/L indomethacin for 12 h. Wheat peptides significantly attenuated the indomethacin-induced decrease in superoxide dismutase and glutathione peroxidase activity. Wheat peptides at 2000 mg/L markedly decreased the expression of the NF-κB in response to indomethacin-induced oxidative stress. This study demonstrated that the addition of wheat peptides to a culture medium significantly inhibited the indomethacin-induced release of malondialdehyde and nitrogen monoxide, and increased antioxidant enzyme activity in IEC-6 cells, thereby providing a possible explanation for the protective effect proposed for wheat peptides in the prevention of indomethacin-induced oxidative stress in small intestinal epithelial cells.

  16. Baicalein Induces Apoptosis and Autophagy via Endoplasmic Reticulum Stress in Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Zhongxia Wang

    2014-01-01

    Full Text Available Background. Hepatocellular carcinoma (HCC remains a disastrous disease and the treatment for HCC is rather limited. Separation and identification of active compounds from traditionally used herbs in HCC treatment may shed light on novel therapeutic drugs for HCC. Methods. Cell viability and colony forming assay were conducted to determine anti-HCC activity. Morphology of cells and activity of caspases were analyzed. Antiapoptotic Bcl-2 family proteins and JNK were also examined. Levels of unfolded protein response (UPR markers were determined and intracellular calcium was assayed. Small interfering RNAs (siRNAs were used to investigate the role of UPR and autophagy in baicalein-induced cell death. Results. Among four studied flavonoids, only baicalein exhibited satisfactory inhibition of viability and colony formation of HCC cells within water-soluble concentration. Baicalein induced apoptosis via endoplasmic reticulum (ER stress, possibly by downregulating prosurvival Bcl-2 family, increasing intracellular calcium, and activating JNK. CHOP was the executor of cell death during baicalein-induced ER stress while eIF2α and IRE1α played protective roles. Protective autophagy was also triggered by baicalein in HCC cells. Conclusion. Baicalein exhibits prominent anti-HCC activity. This flavonoid induces apoptosis and protective autophagy via ER stress. Combination of baicalein and autophagy inhibitors may represent a promising therapy against HCC.

  17. Disruption of O-linked N-Acetylglucosamine Signaling Induces ER Stress and β Cell Failure.

    Science.gov (United States)

    Alejandro, Emilyn U; Bozadjieva, Nadejda; Kumusoglu, Doga; Abdulhamid, Sarah; Levine, Hannah; Haataja, Leena; Vadrevu, Suryakiran; Satin, Leslie S; Arvan, Peter; Bernal-Mizrachi, Ernesto

    2015-12-22

    Nutrient levels dictate the activity of O-linked N-acetylglucosamine transferase (OGT) to regulate O-GlcNAcylation, a post-translational modification mechanism to "fine-tune" intracellular signaling and metabolic status. However, the requirement of O-GlcNAcylation for maintaining glucose homeostasis by regulating pancreatic β cell mass and function is unclear. Here, we reveal that mice lacking β cell OGT (βOGT-KO) develop diabetes and β cell failure. βOGT-KO mice demonstrated increased ER stress and distended ER architecture, and these changes ultimately caused the loss of β cell mass due to ER-stress-induced apoptosis and decreased proliferation. Akt1/2 signaling was also dampened in βOGT-KO islets. The mechanistic role of these processes was demonstrated by rescuing the phenotype of βOGT-KO mice with concomitant Chop gene deletion or genetic reconstitution of Akt2. These findings identify OGT as a regulator of β cell mass and function and provide a direct link between O-GlcNAcylation and β cell survival by regulation of ER stress responses and modulation of Akt1/2 signaling. PMID:26673325

  18. Curcumin targeting the thioredoxin system elevates oxidative stress in HeLa cells

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Wenqing; Zhang, Baoxin; Duan, Dongzhu [State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000 (China); Wu, Jincai [College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000 (China); Fang, Jianguo, E-mail: fangjg@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu 730000 (China); College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, Gansu 730000 (China)

    2012-08-01

    The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH, is ubiquitous in all cells and involved in many redox-dependent signaling pathways. Curcumin, a naturally occurring pigment that gives a specific yellow color in curry food, is consumed in normal diet up to 100 mg per day. This molecule has also been used in traditional medicine for the treatment of a variety of diseases. Curcumin has numerous biological functions, and many of these functions are related to induction of oxidative stress. However, how curcumin elicits oxidative stress in cells is unclear. Our previous work has demonstrated the way by which curcumin interacts with recombinant TrxR1 and alters the antioxidant enzyme into a reactive oxygen species (ROS) generator in vitro. Herein we reported that curcumin can target the cytosolic/nuclear thioredoxin system to eventually elevate oxidative stress in HeLa cells. Curcumin-modified TrxR1 dose-dependently and quantitatively transfers electrons from NADPH to oxygen with the production of ROS. Also, curcumin can drastically down-regulate Trx1 protein level as well as its enzyme activity in HeLa cells, which in turn remarkably decreases intracellular free thiols, shifting the intracellular redox balance to a more oxidative state, and subsequently induces DNA oxidative damage. Furthermore, curcumin-pretreated HeLa cells are more sensitive to oxidative stress. Knockdown of TrxR1 sensitizes HeLa cells to curcumin cytotoxicity, highlighting the physiological significance of targeting TrxR1 by curcumin. Taken together, our data disclose a previously unrecognized prooxidant mechanism of curcumin in cells, and provide a deep insight in understanding how curcumin works in vivo. -- Highlights: ► Curcumin induces oxidative stress by targeting the thioredoxin system. ► Curcumin-modified TrxR quantitatively oxidizes NADPH to generate ROS. ► Knockdown of TrxR1 augments curcumin's cytotoxicity in HeLa cells.

  19. The oxysterol 27-hydroxycholesterol increases β-amyloid and oxidative stress in retinal pigment epithelial cells

    Directory of Open Access Journals (Sweden)

    Dasari Bhanu

    2010-09-01

    Full Text Available Abstract Background Alzheimer's disease (AD and age-related macular degeneration (AMD share several pathological features including β-amyloid (Aβ peptide accumulation, oxidative damage, and cell death. The causes of AD and AMD are not known but several studies suggest disturbances in cholesterol metabolism as a culprit of these diseases. We have recently shown that the cholesterol oxidation metabolite 27-hydroxycholesterol (27-OHC causes AD-like pathology in human neuroblastoma SH-SY5Y cells and in organotypic hippocampal slices. However, the extent to which and the mechanisms by which 27-OHC may also cause pathological hallmarks related to AMD are ill-defined. In this study, the effects of 27-OHC on AMD-related pathology were determined in ARPE-19 cells. These cells have structural and functional properties relevant to retinal pigmented epithelial cells, a target in the course of AMD. Methods ARPE-19 cells were treated with 0, 10 or 25 μM 27-OHC for 24 hours. Levels of Aβ peptide, mitochondrial and endoplasmic reticulum (ER stress markers, Ca2+ homeostasis, glutathione depletion, reactive oxygen species (ROS generation, inflammation and cell death were assessed using ELISA, Western blot, immunocytochemistry, and specific assays. Results 27-OHC dose-dependently increased Aβ peptide production, increased levels of ER stress specific markers caspase 12 and gadd153 (also called CHOP, reduced mitochondrial membrane potential, triggered Ca2+ dyshomeostasis, increased levels of the nuclear factor κB (NFκB and heme-oxygenase 1 (HO-1, two proteins activated by oxidative stress. Additionally, 27-OHC caused glutathione depletion, ROS generation, inflammation and apoptotic-mediated cell death. Conclusions The cholesterol metabolite 27-OHC is toxic to RPE cells. The deleterious effects of this oxysterol ranged from Aβ accumulation to oxidative cell damage. Our results suggest that high levels of 27-OHC may represent a common pathogenic factor for

  20. Yeast CUP1 protects HeLa cells against copper-induced stress

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.X. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China); College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou (China); Ma, Y.F.; Wang, Q.S.; Chen, Z.L.; Liao, R.R.; Pan, Y.C. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China)

    2015-06-12

    As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

  1. Cis-hydroxyproline-induced inhibition of pancreatic cancer cell growth is mediated by endoplasmic reticulum stress

    Institute of Scientific and Technical Information of China (English)

    Christoph Mueller; Joerg Emmrich; Robert Jaster; Dagmar Braun; Stefan Liebe; Gisela Sparmann

    2006-01-01

    AIM: To investigate the biological effects of cishydroxyproline (CHP) on the rat pancreatic carcinoma cell line DSL6A, and to examine the underlying molecular mechanisms.METHODS: The effect of CHP on DSL6A cell proliferation was assessed by using BrdU incorporation. The expression of focal adhesion kinase (FAK) was characterized by Western blotting and immunofluorescence.Induction of endoplasmic reticulum (ER) stress was investigated by using RT-PCR and Western blotting for the glucose-related protein-78 (GRP78) and growth arrest and DNA inducible gene (GADD153). Cell viability was determined through measuring the metabolic activity based on the reduction potential of DSL6A cells. Apoptosis was analyzed by detection of caspase-3 activation and cleavage of poly(ADP-ribose) polymerase (PARP) as well as DNA laddering.RESULTS: In addition to inhibition of proliferation,incubation with CHP induced proteolytic cleavage of FAK and a delocalisation of the enzyme from focal adhesions,followed by a loss of cell adherence. Simultaneously,we could show an increased expression of GRP78 and GADD153, indicating a CHP-mediated activation of the ER stress cascade in the DSL6A cell line. Prolonged incubation of DSL6A cells with CHP finally resulted in apoptotic cell death. Beside L-proline, the inhibition of intracellular proteolysis by addition of a broad spectrum protease inhibitor could abolish the effects of CHP on cellular functions and the molecular processes. In contrast, impeding the activity of apoptosis-executing caspases had no influence on CHP-mediated cell damage.CONCLUSION: Our data suggest that the initiation of ER stress machinery by CHP leads to an activation of intracellular proteolytic processes, including caspaseindependent FAK degradation, resulting in damaging pancreatic carcinoma cells.

  2. Curcumin targeting the thioredoxin system elevates oxidative stress in HeLa cells.

    Science.gov (United States)

    Cai, Wenqing; Zhang, Baoxin; Duan, Dongzhu; Wu, Jincai; Fang, Jianguo

    2012-08-01

    The thioredoxin system, composed of thioredoxin reductase (TrxR), thioredoxin (Trx), and NADPH, is ubiquitous in all cells and involved in many redox-dependent signaling pathways. Curcumin, a naturally occurring pigment that gives a specific yellow color in curry food, is consumed in normal diet up to 100mg per day. This molecule has also been used in traditional medicine for the treatment of a variety of diseases. Curcumin has numerous biological functions, and many of these functions are related to induction of oxidative stress. However, how curcumin elicits oxidative stress in cells is unclear. Our previous work has demonstrated the way by which curcumin interacts with recombinant TrxR1 and alters the antioxidant enzyme into a reactive oxygen species (ROS) generator in vitro. Herein we reported that curcumin can target the cytosolic/nuclear thioredoxin system to eventually elevate oxidative stress in HeLa cells. Curcumin-modified TrxR1 dose-dependently and quantitatively transfers electrons from NADPH to oxygen with the production of ROS. Also, curcumin can drastically down-regulate Trx1 protein level as well as its enzyme activity in HeLa cells, which in turn remarkably decreases intracellular free thiols, shifting the intracellular redox balance to a more oxidative state, and subsequently induces DNA oxidative damage. Furthermore, curcumin-pretreated HeLa cells are more sensitive to oxidative stress. Knockdown of TrxR1 sensitizes HeLa cells to curcumin cytotoxicity, highlighting the physiological significance of targeting TrxR1 by curcumin. Taken together, our data disclose a previously unrecognized prooxidant mechanism of curcumin in cells, and provide a deep insight in understanding how curcumin works in vivo. PMID:22634334

  3. Cell-Activation by Shear Stresses in Abdominal Aortic Aneurysms (AAA)

    Science.gov (United States)

    Salsac, Anne-Virginie; Sparks, Steven; Chomaz, Jean-Marc; Lasheras, Juan C.

    2003-11-01

    Increasing experimental evidence indicates that low and oscillatory shear stresses promote proliferative, thrombotic, adhesive and inflammatory-mediated degenerative conditions throughout the wall of the aorta. These degenerative conditions have been shown to be involved in the pathogenesis of AAAs, a permanent, localized dilatation of the abdominal aorta. The purpose of this study is to measure both the magnitude and the duration of the shear stresses acting on both the arterial walls and on the blood cells inside AAAs, and to characterize their changes as the AAA enlarges. We conducted a parametric in-vitro study of the pulsatile blood flow in elastic models of AAAs while systematically varying the blood flow parameters, and the geometry of the aneurysm's bulging. The instantaneous flow characteristic inside the AAA was measured using DPIV at a sampling rate of 15 Hertz. A "cell-activation parameter" defined as the integral of the product of the magnitude of the shear stress and the time during which the stress acts was computed along each of the blood cell pathlines. The Lagrangian tracking of the blood cells shows that a large majority of them are subjected first to very high level of shear-induced "cell-activation" while later on they are entrained in regions of stasis where their residence time can increase up to several cardiac cycles. This cell-activation followed by the entrainment in low shear regions creates the optimal cell-adhesive and inflammatory-mediated degenerative conditions that are postulated to play an important role in the etiology and progressive enlargement of AAAs.

  4. Agmatine increases proliferation of cultured hippocampal progenitor cells and hippocampal neurogenesis in chronically stressed mice

    Institute of Scientific and Technical Information of China (English)

    Yun-feng LI; Hong-xia CHEN; Ying LIU; You-zhi ZHANG; Yan-qin LIU; Jin LI

    2006-01-01

    Aim:To explore the mechanism of agmatine's antidepressant action.Methods: Male mice were subjected to a variety of unpredictable stressors on a daily basis over a 24-d period.The open-field behaviors of the mice were displayed and recorded using a Videomex-V image analytic system automatically.For bromodeoxyuridine (BrdU;thymidine analog as a marker for dividing cells) labeling,the mice were injected with BrdU (100 mg/kg,ip,twice per d for 2 d),and the hippocampal neurogenesis in stressed mice was measured by immunohistochemistry.The proliferation of cultured hippocampal progenitor cells from neonatal rats was determined by colorimetric assay (cell counting kit-8) and 3H-thymidine incorporation assay.Results:After the onset of chronic stress,the locomotor activity of the mice in the open field significantly decreased,while coadministration of agmatine 10 mg/kg (po) blocked it.Furthermore,the number of BrdU-labeled cells in the hippocampal dentate gyrus significantly decreased in chronically stressed mice, which was also blocked by chronic coadministration with agmatine 10 mg/kg (po). Four weeks after the BrdU injection, some of the new born cells matured and became neurons, as determined by double labeling for BrdU and neuron specific enolase (NSE), a marker for mature neurons.In vitro treatment with agmatine 0.1-10 μmo1/L for 3 d significantly increased the proliferation of the cultured hippocampal progenitor cells in a dose-dependent manner.Conclusion:We have found that agmatine increases proliferation of hippocampal progenitor cells in vitro and the hippocampal neurogenesis in vivo in chronically stressed mice.This may be one of the important mechanisms involved in agmatine's antidepressant action.

  5. Mono-2-ethylhexyl phthalate induces oxidative stress responses in human placental cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Tetz, Lauren M., E-mail: ltetz@umich.edu [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States); Cheng, Adrienne A.; Korte, Cassandra S. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States); Giese, Roger W.; Wang, Poguang [Department of Pharmaceutical Sciences, Northeastern University, 360 Huntingon Ave, Boston, MA 02115 (United States); Harris, Craig; Meeker, John D.; Loch-Caruso, Rita [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109-2029 (United States)

    2013-04-01

    Di-2-ethylhexyl phthalate (DEHP) is an environmental contaminant commonly used as a plasticizer in polyvinyl chloride products. Exposure to DEHP has been linked to adverse pregnancy outcomes in humans including preterm birth, low birth-weight, and pregnancy loss. Although oxidative stress is linked to the pathology of adverse pregnancy outcomes, effects of DEHP metabolites, including the active metabolite, mono-2-ethylhexyl phthalate (MEHP), on oxidative stress responses in placental cells have not been previously evaluated. The objective of the current study is to identify MEHP-stimulated oxidative stress responses in human placental cells. We treated a human placental cell line, HTR-8/SVneo, with MEHP and then measured reactive oxygen species (ROS) generation using the dichlorofluorescein assay, oxidized thymine with mass-spectrometry, redox-sensitive gene expression with qRT-PCR, and apoptosis using a luminescence assay for caspase 3/7 activity. Treatment of HTR-8 cells with 180 μM MEHP increased ROS generation, oxidative DNA damage, and caspase 3/7 activity, and resulted in differential expression of redox-sensitive genes. Notably, 90 and 180 μM MEHP significantly induced mRNA expression of prostaglandin-endoperoxide synthase 2 (PTGS2), an enzyme important for synthesis of prostaglandins implicated in initiation of labor. The results from the present study are the first to demonstrate that MEHP stimulates oxidative stress responses in placental cells. Furthermore, the MEHP concentrations used were within an order of magnitude of the highest concentrations measured previously in human umbilical cord or maternal serum. The findings from the current study warrant future mechanistic studies of oxidative stress, apoptosis, and prostaglandins as molecular mediators of DEHP/MEHP-associated adverse pregnancy outcomes. - Highlights: ► MEHP increased reactive oxygen species, oxidative DNA damage, and caspase activity. ► MEHP induced expression of PTGS2, a gene

  6. Lipocalin 2, a new GADD153 target gene, as an apoptosis inducer of endoplasmic reticulum stress in lung cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Hsin, I-Lun; Hsiao, Yueh-Chieh [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Wu, Ming-Fang [Division of Chest Medicine, Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 40201, Taiwan (China); School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Jan, Ming-Shiou [Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Tang, Sheau-Chung; Lin, Yu-Wen [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Hsu, Chung-Ping, E-mail: cliff@vghtc.com.tw [Department of Thoracic Surgery, Veterans General Hospital—Taichung, Taichung 40705, Taiwan (China); Department of Surgery, National Yang-Ming University School of Medicine and Taipei Veterans General Hospital, Taipei 11221, Taiwan (China); Ko, Jiunn-Liang, E-mail: jlko@csmu.edu.tw [Institute of Medical and Molecular Toxicology, Chung Shan Medical University, Taichung 40201, Taiwan (China); Institute of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan (China); Division of Chest Medicine, Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 40201, Taiwan (China)

    2012-09-15

    Endoplasmic reticulum (ER) stress is activated under severe cellular conditions. GADD153, a member of the C/EBP family, is an unfolded protein response (UPR) responsive transcription factor. Increased levels of lipocalin 2, an acute phase protein, have been found in several epithelial cancers. The aim of this study is to investigate the function of lipocalin 2 in lung cancer cells under ER stress. Treatment with thapsigargin, an ER stress activator, led to increases in cytotoxicity, ER stress, apoptosis, and lipocalin 2 expression in A549 cells. GADD153 silencing decreased lipocalin 2 expression in A549 cells. On chromatin immunoprecipitation assay, ER stress increased GADD153 DNA binding to lipocalin 2 promoter. Furthermore, silencing of lipocalin 2 mitigated ER stress-mediated apoptosis in A549 cells. Our findings demonstrated that lipocalin 2 is a new GADD153 target gene that mediates ER stress-induced apoptosis. Highlights: ► We demonstrate that Lipocalin 2 is a new GADD153 target gene. ► Lipocalin 2 mediates ER stress-induced apoptosis. ► ER stress-induced lipocalin 2 expression is calcium-independent in A549 cells. ► Lipocalin 2 dose not play a major role in ER stress-induced autophagy.

  7. Dissecting Regional Variations in Stress Fiber Mechanics in Living Cells with Laser Nanosurgery

    Energy Technology Data Exchange (ETDEWEB)

    Tanner, Kandice; Boudreau, Aaron; Bissell, Mina J; Kumar, Sanjay

    2010-03-02

    The ability of a cell to distribute contractile stresses across the extracellular matrix in a spatially heterogeneous fashion underlies many cellular behaviors, including motility and tissue assembly. Here we investigate the biophysical basis of this phenomenon by using femtosecond laser nanosurgery to measure the viscoelastic recoil and cell-shape contributions of contractile stress fibers (SFs) located in specific compartments of living cells. Upon photodisruption and recoil, myosin light chain kinase-dependent SFs located along the cell periphery display much lower effective elasticities and higher plateau retraction distances than Rho-associated kinase-dependent SFs located in the cell center, with severing of peripheral fibers uniquely triggering a dramatic contraction of the entire cell within minutes of fiber irradiation. Image correlation spectroscopy reveals that when one population of SFs is pharmacologically dissipated, actin density flows toward the other population. Furthermore, dissipation of peripheral fibers reduces the elasticity and increases the plateau retraction distance of central fibers, and severing central fibers under these conditions triggers cellular contraction. Together, these findings show that SFs regulated by different myosin activators exhibit different mechanical properties and cell shape contributions. They also suggest that some fibers can absorb components and assume mechanical roles of other fibers to stabilize cell shape.

  8. Effect of Nɛ-carboxymethyllysine on oxidative stress and the glutathione system in beta cells

    Directory of Open Access Journals (Sweden)

    Daniëlle M.P.H.J. Boesten

    2014-01-01

    Full Text Available One of the pathways involved in the pathogenesis of diabetic complications is the formation of excessive levels of advanced glycation end (AGE products. Nɛ-carboxymethyllysine (CML is one of the best-characterized AGEs. Because little is known about the effects of AGEs on pancreatic beta cells, we investigated the effect of CML on human pancreatic cells and determined the activity and gene expression of glutathione system components. CML at a concentration of 0.5 mM induced cell death in human pancreatic beta cells, which was accompanied by increased intracellular oxidative stress. No changes in the gene expression of the receptor for AGEs (RAGE were found, although an increase in the level of a target cytokine of RAGE after CML exposure was observed. Additionally we found that CML lowered the levels of GSH and affected the activity and expression of other components of the glutathione system. These changes indicate that the cells are even more vulnerable for oxidative stress after exposure to CML. Since beta cells are low in antioxidant enzymes and repair for oxidized DNA, CML, but most likely also other AGEs, accelerates beta cell dysfunction and increases beta cell death during chronic hyperglycemia.

  9. Dexamethasone acts as a radiosensitizer in three astrocytoma cell lines via oxidative stress.

    Science.gov (United States)

    Ortega-Martínez, Sylvia

    2015-08-01

    Glucocorticoids (GCs), which act on stress pathways, are well-established in the co-treatment of different kinds of tumors; however, the underlying mechanisms by which GCs act are not yet well elucidated. As such, this work investigates the role of glucocorticoids, specifically dexamethasone (DEXA), in the processes referred to as DNA damage and DNA damage response (DDR), establishing a new approach in three astrocytomas cell lines (CT2A, APP.PS1 L.1 and APP.PS1 L.3). The results show that DEXA administration increased the basal levels of gamma-H2AX foci, keeping them higher 4h after irradiation (IR) of the cells, compared to untreated cells. This means that DEXA might cause increased radiosensitivity in these cell lines. On the other hand, DEXA did not have an apparent effect on the formation and disappearance of the 53BP1 foci. Furthermore, it was found that DEXA administered 2h before IR led to a radical change in DNA repair kinetics, even DEXA does not affect cell cycle. It is important to highlight that DEXA produced cell death in these cell lines compared to untreated cells. Finally and most important, the high levels of gamma-H2AX could be reversed by administration of ascorbic acid, a potent blocker of reactive oxygen species, suggesting that DEXA acts by causing DNA damage via oxidative stress. These exiting findings suggest that DEXA might promote radiosensitivity in brain tumors, specifically in astrocytoma-like tumors.

  10. A Role of Fluoride on Free Radical Generation and Oxidative Stress in BV-2 Microglia Cells

    Directory of Open Access Journals (Sweden)

    Xi Shuhua

    2012-01-01

    Full Text Available The generation of ROS and lipid peroxidation has been considered to play an important role in the pathogenesis of chronic fluoride toxicity. In the present study, we observed that fluoride activated BV-2 microglia cell line by observing OX-42 expression in immunocytochemistry. Intracellular superoxide dismutase (SOD, glutathione (GSH, malondialdehyde (MDA, reactive oxygen species (ROS, superoxide anions (O2∙-, nitric oxide synthase (NOS, nitrotyrosine (NT and nitric oxide (NO, NOS in cell medium were determined for oxidative stress assessment. Our study found that NaF of concentration from 5 to 20 mg/L can stimuli BV-2 cells to change into activated microglia displaying upregulated OX-42 expression. SOD activities significantly decreased in fluoride-treated BV-2 cells as compared with control, and MDA concentrations and contents of ROS and O2∙- increased in NaF-treated cells. Activities of NOS in cells and medium significantly increased with fluoride concentrations in a dose-dependent manner. NT concentrations also increased significantly in 10 and 50 mg/L NaF-treated cells compared with the control cells. Our present study demonstrated that toxic effects of fluoride on the central nervous system possibly partly ascribed to activiting of microglia, which enhanced oxidative stress induced by ROS and reactive nitrogen species.

  11. Effect of cell size and shear stress on bacterium growth rate

    Science.gov (United States)

    Fadlallah, Hadi; Jarrahi, Mojtaba; Herbert, Éric; Peerhossaini, Hassan; PEF Team

    2015-11-01

    Effect of shear stress on the growth rate of Synechocystis and Chlamydomonas cells is studied. An experimental setup was prepared to monitor the growth rate of the microorganisms versus the shear rate inside a clean room, under atmospheric pressure and 20 °C temperature. Digital magnetic agitators are placed inside a closed chamber provided with airflow, under a continuous uniform light intensity over 4 weeks. In order to study the effect of shear stress on the growth rate, different frequencies of agitation are tested, 2 vessels filled with 150 ml of each specie were placed on different agitating system at the desired frequency. The growth rate is monitored daily by measuring the optical density and then correlate it to the cellular concentration. The PH was adjusted to 7 in order to maintain the photosynthetic activity. Furthermore, to measure the shear stress distribution, the flow velocity field was measured using PIV. Zones of high and low shear stress were identified. Results show that the growth rate is independent of the shear stress magnitude, mostly for Synechocystis, and with lower independency for Chlamydomonas depending on the cell size for each species.

  12. Puerarin prevents high glucose-induced apoptosis of Schwann cells by inhibiting oxidative stress

    Institute of Scientific and Technical Information of China (English)

    Yingying Wu; Bing Xue; Xiaojin Li; Hongchen Liu

    2012-01-01

    Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabeticperipheral neuropathy.Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective in increasing superoxide dismutase activity.This study sought to investigate the neuroprotective effect of puerarin on high glucose-induced oxidative stress and Schwann cell apoptosis in vitro.Intracellular reactive oxygen radicals and mitochondrial transmembrane potential were detected by flow cytometry analysis.Apoptosis was confirmed by TUNEL and oxidative stress was monitored using an enzyme-linked immunosorbent assay for the DNA marker 8-hydroxy-2-deoxyguanosine.The expression levels of bax and bcl-2 were analyzed by quantitative real-time reverse transcriptase-PCR,while protein expression of cleaved caspase-3 and-9 were analyzed by means of western blotting.Results suggested that puerarin treatment inhibited high glucose-induced oxidative stress,mitochondrial depolarization and apoptosis in a dose-dependent manner.Furthermore,puerarin treatment downregulated Bax expression,upregulated bcl-2 expression and attenuated the activation of caspase-3 and-9.Overall,our results indicated that puerarin antagonized high glucose-induced oxidative stress and apoptosis in Schwann cells.

  13. Downregulation of Cdc6 and pre-replication complexes in response to methionine stress in breast cancer cells.

    Science.gov (United States)

    Booher, Keith; Lin, Da-Wei; Borrego, Stacey L; Kaiser, Peter

    2012-12-01

    Methionine and homocysteine are metabolites in the transmethylation pathway leading to synthesis of the methyl-donor S-adenosylmethionine (SAM). Most cancer cells stop proliferating during methionine stress conditions, when methionine is replaced in the growth media by its immediate metabolic precursor homocysteine (Met-Hcy+). Non-transformed cells proliferate in Met-Hcy+ media, making the methionine metabolic requirement of cancer cells an attractive target for therapy, yet there is relatively little known about the molecular mechanisms governing the methionine stress response in cancer cells. To study this phenomenon in breast cancer cells, we selected methionine-independent-resistant cell lines derived from MDAMB468 breast cancer cells. Resistant cells grew normally in Met-Hcy+ media, whereas their parental MDAMB468 cells rapidly arrest in the G 1 phase. Remarkably, supplementing Met-Hcy+ growth media with S-adenosylmethionine suppressed the cell proliferation defects, indicating that methionine stress is a consequence of SAM limitation rather than low amino acid concentrations. Accordingly, mTORC1 activity, the primary effector responding to amino acid limitation, remained high. However, we found that levels of the replication factor Cdc6 decreased and pre-replication complexes were destabilized in methionine-stressed MDAMB468 but not resistant cells. Our study characterizes metabolite requirements and cell cycle responses that occur during methionine stress in breast cancer cells and helps explain the metabolic uniqueness of cancer cells.

  14. Cadmium Chloride Induces DNA Damage and Apoptosis of Human Liver Carcinoma Cells via Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Anthony Skipper

    2016-01-01

    Full Text Available Cadmium is a heavy metal that has been shown to cause its toxicity in humans and animals. Many documented studies have shown that cadmium produces various genotoxic effects such as DNA damage and chromosomal aberrations. Ailments such as bone disease, renal damage, and several forms of cancer are attributed to overexposure to cadmium.  Although there have been numerous studies examining the effects of cadmium in animal models and a few case studies involving communities where cadmium contamination has occurred, its molecular mechanisms of action are not fully elucidated. In this research, we hypothesized that oxidative stress plays a key role in cadmium chloride-induced toxicity, DNA damage, and apoptosis of human liver carcinoma (HepG2 cells. To test our hypothesis, cell viability was determined by MTT assay. Lipid hydroperoxide content stress was estimated by lipid peroxidation assay. Genotoxic damage was tested by the means of alkaline single cell gel electrophoresis (Comet assay. Cell apoptosis was measured by flow cytometry assessment (Annexin-V/PI assay. The result of MTT assay indicated that cadmium chloride induces toxicity to HepG2 cells in a concentration-dependent manner, showing a 48 hr-LD50 of 3.6 µg/mL. Data generated from lipid peroxidation assay resulted in a significant (p < 0.05 increase of hydroperoxide production, specifically at the highest concentration tested. Data obtained from the Comet assay indicated that cadmium chloride causes DNA damage in HepG2 cells in a concentration-dependent manner. A strong concentration-response relationship (p < 0.05 was recorded between annexin V positive cells and cadmium chloride exposure. In summary, these in vitro studies provide clear evidence that cadmium chloride induces oxidative stress, DNA damage, and programmed cell death in human liver carcinoma (HepG2 cells.

  15. Changes in human pluripotent stem cell gene expression after genotoxic stress exposures

    Institute of Scientific and Technical Information of China (English)

    Mykyta; V; Sokolov; Ronald; D; Neumann

    2014-01-01

    Human pluripotent stem cells(h PSCs) represent heterogeneous populations, including induced pluripotent stem cells(i PSCs), endogenous plastic somatic cells, and embryonic stem cells(ESCs). Human ESCs are derived from the inner cell mass of the blastocyst, and they are characterized by the abilities to self-renew indefinitely, and to give rise to all cell types of embryonic lineage(pluripotency) under the guidance of the appropriate chemical, mechanical and environmental cues. The combination of these critical features is unique to h ESCs, and set them apart from other human cells. The expectations are high to utilize h ESCs for treating injuries and degenerative diseases; for modeling of complex illnesses and development; for screening and testing of pharmacological products; and for examining toxicity, mutagenicity, teratogenicity, and potential carcinogenic effects of a variety of environmental factors, including ionizing radiation(IR). Exposures to genotoxic stresses, such as background IR, are unavoidable; moreover, IR is widely used in diagnostic and therapeutic procedures in medicine on a routine basis. One of the key outcomes of cell exposures to IR is the change in gene expression, which may underlie the ultimate h ESCs fate after such a stress. However, gaps in our knowledge about basic biology of h ESCs impose a serious limitation to fully realize the potential of h ESCs in practice. The purpose of this review is to examine the available evidence of alterations in gene expression in human pluripotent stem cells after genotoxic stress, and to discuss strategies for future research in this important area.

  16. Copper ions stimulate the proliferation of hepatic stellate cells via oxygen stress in vitro.

    Science.gov (United States)

    Xu, San-qing; Zhu, Hui-yun; Lin, Jian-guo; Su, Tang-feng; Liu, Yan; Luo, Xiao-ping

    2013-02-01

    This study examined the effect of copper ions on the proliferation of hepatic stellate cells (HSCs) and the role of oxidative stress in this process in order to gain insight into the mechanism of hepatic fibrosis in Wilson's disease. LX-2 cells, a cell line of human HSCs, were cultured in vitro and treated with different agents including copper sulfate, N-acetyl cysteine (NAC) and buthionine sulfoximine (BSO) for different time. The proliferation of LX-2 cells was measured by non-radioactive cell proliferation assay. Real-time PCR and Western blotting were used to detect the mRNA and protein expression of platelet-derived growth factor receptor β subunit (PDGFβR), ELISA to determine the level of glutathione (GSH) and oxidized glutathione (GSSG), dichlorofluorescein assay to measure the level of reactive oxygen species (ROS), and lipid hydroperoxide assay to quantify the level of lipid peroxide (LPO). The results showed that copper sulfate over a certain concentration range could promote the proliferation of LX-2 cells in a time- and dose-dependent manner. The effect was most manifest when LX-2 cells were treated with copper sulfate at a concentration of 100 μmol/L for 24 h. Additionally, copper sulfate could dose-dependently increase the levels of ROS and LPO, and decrease the ratio of GSH/GSSG in LX-2 cells. The copper-induced increase in mRNA and protein expression of PDGFβR was significantly inhibited in LX-2 cells pre-treated with NAC, a precursor of GSH, and this phenomenon could be reversed by the intervention of BSO, an inhibitor of NAC. It was concluded that copper ions may directly stimulate the proliferation of HSCs via oxidative stress. Anti-oxidative stress therapies may help suppress the copper-induced activation and proliferation of HSCs.

  17. Endoplasmic reticulum stress is involved in the response of human laryngeal carcinoma cells to Carboplatin but is absent in Carboplatin-resistant cells.

    Directory of Open Access Journals (Sweden)

    Anamaria Brozovic

    Full Text Available The major obstacle of successful tumor treatment with carboplatin (CBP is the development of drug resistance. In the present study, we found that following treatment with CBP the amount of platinum which enters the human laryngeal carcinoma (HEp2-derived CBP-resistant (7T cells is reduced relative to the parental HEp2. As a consequence, the formation of reactive oxidative species (ROS is reduced, the induction of endoplasmic reticulum (ER stress is diminished, the amount of inter- and intrastrand cross-links is lower, and the induction of apoptosis is depressed. In HEp2 cells, ROS scavenger tempol, inhibitor of ER stress salubrinal, as well as gene silencing of ER stress marker CCAAT/enhancer-binding protein (CHOP increases their survival and renders them as resistant to CBP as 7T cell subline but did not influence the survival of 7T cells. Our results suggest that in HEp2 cells CBP-induced ROS is a stimulus for ER stress. To the contrary, despite the ability of CBP to induce formation of ROS and activate ER stress in 7T cells, the cell death mechanism in 7T cells is independent of ROS induction and activation of ER stress. The novel signaling pathway of CBP-driven toxicity that was found in the HEp2 cell line, i.e. increased ROS formation and induction of ER stress, may be predictive for therapeutic response of epithelial cancer cells to CBP-based therapy.

  18. Physical properties of beryllium oxide - Irradiation effects; Proprietes physiques et caracteristiques mecaniques de l'oxyde de beryllium fritte - Effet de l'irradiation et guerison

    Energy Technology Data Exchange (ETDEWEB)

    Elston, J.; Caillat, R. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    This work has been carried out in view of determining several physical properties of hot-pressed beryllium oxide under various conditions and the change of these properties after irradiation. Special attention has been paid on to the measurement of the thermal conductivity coefficient and thermal diffusivity coefficient. Several designs for the measurement of the thermal conductivity coefficient have been achieved. They permit its determination between 50 and 300 deg. C, between 400 and 800 deg. C. Some measurements have been made above 1000 deg. C. In order to measure the thermal diffusivity coefficient, we heat a perfectly flat surface of a sample in such a way that the heat flux is modulated (amplitude and frequency being adjustable). The thermal diffusivity coefficient is deduced from the variations of temperature observed on several spots. Tensile strength; compressive strength; expansion coefficient; sound velocity and crystal parameters have been also measured. Some of the measurements have been carried out after neutron irradiation. Some data have been obtained on the change of the properties of beryllium oxide depending on the integrated neutron flux. (author)Fren. [French] L'objet de cette etude est la determination de plusieurs proprietes physiques de l'oxyde de beryllium fritte sous charge dans differentes conditions et l'evolution de ces proprietes apres irradiation. Une attention particuliere a ete portee sur la mesure de la conductibilite et de la diffusivite thermiques. Differents montages ont ete realises pour mesurer la conductibilite thermique. Ils permettent la determination entre 50 et 300 deg. C, entre 400 et 800 deg. C; quelques mesures ont ete faites au-dessus de 1000 deg. C. Pour la mesure du coefficient de diffusivite thermique, on realise une attaque thermique, de frequence et d'amplitude reglables d'une face parfaitement plane d'un echantillon d'oxyde de beryllium. Les variations de temperature sont

  19. Bystander effects and compartmental stress response to X-ray irradiation in L929 cells.

    Science.gov (United States)

    Temelie, Mihaela; Stroe, Daniela; Petcu, Ileana; Mustaciosu, Cosmin; Moisoi, Nicoleta; Savu, Diana

    2016-08-01

    Bystander effects are indirect consequences of radiation and many other stress factors. They occur in cells that are not directly exposed to these factors, but receive signals from affected cells either by gap junctions or by molecules released in the medium. Characterizing these effects and deciphering the underlying mechanisms involved in radiation-induced bystander effects are relevant for cancer radiotherapy and radioprotection. At doses of X-ray radiation 0.5 and 1 Gy, we detected bystander effects as increased numbers of micronuclei shortly after the treatment, through medium transfer and by co-cultures. Interestingly, bystander cells did not exhibit long-term adverse changes in viability. Evaluation of several compartmental stress markers (CHOP, BiP, mtHsp60, cytHsp70) by qRT-PCR did not reveal expression changes at transcriptional level. We investigated the involvement of ROS and NO in this process by addition of specific scavengers of these molecules, DMSO or c-PTIO in the transferred medium. This approach proved that ROS but not NO is involved in the induction of lesions in the acceptor cells. These results indicate that L929 cells are susceptible to stress effects of radiation-induced bystander signaling. PMID:27025606

  20. Stochastic modeling and experimental analysis of phenotypic switching and survival of cancer cells under stress

    Science.gov (United States)

    Zamani Dahaj, Seyed Alireza; Kumar, Niraj; Sundaram, Bala; Celli, Jonathan; Kulkarni, Rahul

    The phenotypic heterogeneity of cancer cells is critical to their survival under stress. A significant contribution to heterogeneity of cancer calls derives from the epithelial-mesenchymal transition (EMT), a conserved cellular program that is crucial for embryonic development. Several studies have investigated the role of EMT in growth of early stage tumors into invasive malignancies. Also, EMT has been closely associated with the acquisition of chemoresistance properties in cancer cells. Motivated by these studies, we analyze multi-phenotype stochastic models of the evolution of cancers cell populations under stress. We derive analytical results for time-dependent probability distributions that provide insights into the competing rates underlying phenotypic switching (e.g. during EMT) and the corresponding survival of cancer cells. Experimentally, we evaluate these model-based predictions by imaging human pancreatic cancer cell lines grown with and without cytotoxic agents and measure growth kinetics, survival, morphological changes and (terminal evaluation of) biomarkers with associated epithelial and mesenchymal phenotypes. The results derived suggest approaches for distinguishing between adaptation and selection scenarios for survival in the presence of external stresses.

  1. Bufotalin-induced apoptosis in osteoblastoma cells is associated with endoplasmic reticulum stress activation.

    Science.gov (United States)

    Zhu, Yun-Rong; Xu, Yong; Fang, Jian-Feng; Zhou, Feng; Deng, Xiong-Wei; Zhang, Yun-Qing

    2014-08-15

    The search for novel and more efficient chemo-agents against malignant osteoblastoma is important. In this study, we examined the potential anti-osteoblastoma function of bufotalin, and studied the underlying mechanisms. Our results showed that bufotalin induced osteoblastoma cell death and apoptosis in dose- and time-dependent manners. Further, bufotalin induced endoplasmic reticulum (ER) stress activation in osteoblastoma cells, the latter was detected by the induction of C/EBP homologous protein (CHOP), phosphorylation of inositol-requiring enzyme 1 (IRE1) and PKR-like endoplasmic reticulum kinase (PERK), as well as caspase-12 activation. Conversely, the ER stress inhibitor salubrinal, the caspase-12 inhibitor z-ATAD-fmk as well as CHOP depletion by shRNA significantly inhibited bufotalin-induced osteoblastoma cell death and apoptosis. Finally, by using a mice xenograft model, we demonstrated that bufotalin inhibited U2OS osteoblastoma cell growth in vivo. In summary, our results suggest that ER stress contributes to bufotalin-induced apoptosis in osteoblastoma cells. Bufotalin might be investigated as a novel anti-osteoblastoma agent. PMID:25068992

  2. Plastid osmotic stress influences cell differentiation at the plant shoot apex.

    Science.gov (United States)

    Wilson, Margaret E; Mixdorf, Matthew; Berg, R Howard; Haswell, Elizabeth S

    2016-09-15

    The balance between proliferation and differentiation in the plant shoot apical meristem is controlled by regulatory loops involving the phytohormone cytokinin and stem cell identity genes. Concurrently, cellular differentiation in the developing shoot is coordinated with the environmental and developmental status of plastids within those cells. Here, we employ an Arabidopsis thaliana mutant exhibiting constitutive plastid osmotic stress to investigate the molecular and genetic pathways connecting plastid osmotic stress with cell differentiation at the shoot apex. msl2 msl3 mutants exhibit dramatically enlarged and deformed plastids in the shoot apical meristem, and develop a mass of callus tissue at the shoot apex. Callus production in this mutant requires the cytokinin receptor AHK2 and is characterized by increased cytokinin levels, downregulation of cytokinin signaling inhibitors ARR7 and ARR15, and induction of the stem cell identity gene WUSCHEL Furthermore, plastid stress-induced apical callus production requires elevated plastidic reactive oxygen species, ABA biosynthesis, the retrograde signaling protein GUN1, and ABI4. These results are consistent with a model wherein the cytokinin/WUS pathway and retrograde signaling control cell differentiation at the shoot apex. PMID:27510974

  3. Effect of Gelam Honey on the Oxidative Stress-Induced Signaling Pathways in Pancreatic Hamster Cells

    Directory of Open Access Journals (Sweden)

    Kalaivani Batumalaie

    2013-01-01

    Full Text Available Background. Oxidative stress induced by reactive oxygen and nitrogen species is critically involved in the impairment of β-cell function during the development of diabetes. Methods. HIT-T15 cells were cultured in 5% CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 µg/mL as well as quercetin (20, 40, 60, and 80 µM, prior to stimulation by 20 and 50 mM of glucose. Cell lysate was collected to determine the effect of honey extracts and quercetin on the stress activated NF-κB, MAPK pathways, and the Akt (ser473 activated insulin signaling pathway. Results. HIT-T15 cells cultured under hyperglycemic conditions demonstrated insulin resistance with a significant increase in the levels of MAPK, NF-κB, and IRS-1 serine phosphorylation (ser307; however, Akt expression and insulin contents are significantly decreased. Pretreatment with quercetin and Gelam honey extract improved insulin resistance and insulin content by reducing the expression of MAPK, NF-κB, and IRS-1 serine phosphorylation (ser307 and increasing the expression of Akt significantly. Conclusion. Gelam honey-induced differential expression of MAPK, NF-κB, IRS-1 (ser307, and Akt in HIT-T15 cells shows that Gelam honey exerts protective effects against diabetes- and hyperglycemia-induced oxidative stress by improving insulin content and insulin resistance.

  4. Racial differences in the responses to shear stress in human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Feairheller DL

    2011-07-01

    Full Text Available Deborah L Feairheller1,4, Joon-Young Park2, Victor Rizzo3, Boa Kim2, Michael D Brown1,31Hypertension, Molecular and Applied Physiology Laboratory, 2Cardiovascular Genomics Laboratory, Department of Kinesiology, 3Cardiovascular Research Center, School of Medicine, Temple University, Philadelphia, PA, USA; 4Exercise and Metabolic Disease Research Laboratory, School of Nursing, University of California Los Angeles, Los Angeles, CA, USABackground: African American ethnicity is an independent risk factor for exaggerated oxidative stress, which is related to inflammation, hypertension, and cardiovascular disease. Recently, we reported that in vitro oxidative stress and inflammation levels differ between African American and Caucasian human umbilical vein endothelial cells (HUVECs, African American HUVECs having higher levels of both. However, it remains to be shown whether the cells would respond differently to external stimuli.Methods: We used a cone and plate viscometer to apply laminar shear stress (LSS as an aerobic exercise mimetic to compare the responses by race. HUVECs were exposed to static conditions (no LSS, low LSS (5 dyne/cm2, and moderate LSS (20 dyne/cm2.Results: It was found that African American HUVECs had higher levels of oxidative stress under static conditions, and when LSS was applied protein expression levels (NADPH oxidase NOX2, NOX4 and p47phox subunits, eNOS, SOD2, and catalase and biomarkers (NO, SOD, and total antioxidant capacity were modulated to similar levels between race.Conclusion: African American HUVECs may be more responsive to LSS stimulus indicating that aerobic exercise prescriptions may be valuable for this population since the potential exists for large in vivo improvements in oxidative stress levels along the endothelial layer in response to increased shear flow.Keywords: shear stress, African American, NADPH oxidase, HUVECs, oxidative stress

  5. Stanniocalcin 2 enhances mesenchymal stem cell survival by suppressing oxidative stress.

    Science.gov (United States)

    Kim, Pyung-Hwan; Na, Sang-Su; Lee, Bomnaerin; Kim, Joo-Hyun; Cho, Je-Yoel

    2015-12-01

    To overcome the disadvantages of stem cell-based cell therapy like low cell survival at the disease site, we used stanniocalcin 2 (STC2), a family of secreted glycoprotein hormones that function to inhibit apoptosis and oxidative damage and to induce proliferation. STC2 gene was transfected into two kinds of stem cells to prolong cell survival and protect the cells from the damage by oxidative stress. The stem cells expressing STC2 exhibited increased cell viability and improved cell survival as well as elevated expression of the pluripotency and self-renewal markers (Oct4 and Nanog) under sub-lethal oxidative conditions. Up-regulation of CDK2 and CDK4 and down-regulation of cell cycle inhibitors p16 and p21 were observed after the delivery of STC2. Furthermore, STC2 transduction activated pAKT and pERK 1/2 signal pathways. Taken together, the STC2 can be used to enhance cell survival and maintain long-term stemness in therapeutic use of stem cells.

  6. Investigation of reliability attributes and accelerated stress factors on terrestrial solar cells. Third annual report

    Energy Technology Data Exchange (ETDEWEB)

    Lathrop, J.W.; Hartman, R.A.; Saylor, C.R.

    1981-01-01

    The third year of the accelerated reliability testing program concentrated on electrical measurement instrumentation and in modeling cell behavior in the second quadrant. In addition, some preliminary work was done on correlating cell color changes with electrical degradation. Not reported are results of continuing accelerated stress tests on state of the art cells. A number of new cells were added to the program, but not in time for sufficient data to be obtained, while the older cells are undergoing extended test periods and new data are not yet available on them. The all-digital, microprocessor controlled, short interval tester, which was designed and fabricated, has replaced the manual measurement procedure formerly used. This has improved measurement accuracy and repeatability, reduced measurement time, and through coordinated data management procedures, eliminated data errors. A complete description of the tester including schematics and software is given and its operating procedures described. A computer model, based on the thermal and electrical properties of the cells and encapsulating materials, was developed to relate cell temperature to electrical characteristics in the second quadrant. This model adequately predicted the behavior of both encapsulated and unencapsulated cells, although accurate temperature measurements on encapsulated cells were difficult to obtain. In addition, only cells of one type were used for comparison and other cell types may require different parameter values for fitting. Use of the model should permit the prediction of a cell's sensitivity to degradation in the second quadrant. The computer program is listed together with a description of its operation.

  7. Stress Hyperglycemia, Insulin Treatment, and Innate Immune Cells

    Directory of Open Access Journals (Sweden)

    Fangming Xiu

    2014-01-01

    Full Text Available Hyperglycemia (HG and insulin resistance are the hallmarks of a profoundly altered metabolism in critical illness resulting from the release of cortisol, catecholamines, and cytokines, as well as glucagon and growth hormone. Recent studies have proposed a fundamental role of the immune system towards the development of insulin resistance in traumatic patients. A comprehensive review of published literatures on the effects of hyperglycemia and insulin on innate immunity in critical illness was conducted. This review explored the interaction between the innate immune system and trauma-induced hypermetabolism, while providing greater insight into unraveling the relationship between innate immune cells and hyperglycemia. Critical illness substantially disturbs glucose metabolism resulting in a state of hyperglycemia. Alterations in glucose and insulin regulation affect the immune function of cellular components comprising the innate immunity system. Innate immune system dysfunction via hyperglycemia is associated with a higher morbidity and mortality in critical illness. Along with others, we hypothesize that reduction in morbidity and mortality observed in patients receiving insulin treatment is partially due to its effect on the attenuation of the immune response. However, there still remains substantial controversy regarding moderate versus intensive insulin treatment. Future studies need to determine the integrated effects of HG and insulin on the regulation of innate immunity in order to provide more effective insulin treatment regimen for these patients.

  8. Therapeutic effect of bone marrow mesenchymal stem cells on cold stress induced changes in the hippocampus of rats

    Institute of Scientific and Technical Information of China (English)

    Saravana Kumar Sampath Kumar; Saraswathi Perumal; Vijayaraghavan Rajagopalan

    2014-01-01

    The present study aims to evaluate the effect of bone marrow mesenchymal stem cells on cold stress induced neuronal changes in hippocampal CA1 region of Wistar rats. Bone marrow mes-enchymal stem cells were isolated from a 6-week-old Wistar rat. Bone marrow from adult femora and tibia was collected and mesenchymal stem cells were cultured in minimal essential medium containing 10% heat-inactivated fetal bovine serum and were sub-cultured. Passage 3 cells were analyzed by lfow cytometry for positive expression of CD44 and CD90 and negative expression of CD45. Once CD44 and CD90 positive expression was achieved, the cells were cultured again to 90% conlfuence for later experiments. Twenty-four rats aged 8 weeks old were randomly and evenly divided into normal control, cold water swim stress (cold stress), cold stress + PBS (intra-venous infusion), and cold stress + bone marrow mesenchymal stem cells (1 × 106; intravenous infusion) groups. The total period of study was 60 days which included 1 month stress period followed by 1 month treatment. Behavioral functional test was performed during the entire study period. After treatment, rats were sacriifced for histological studies. Treatment with bone marrow mesenchymal stem cells signiifcantly increased the number of neuronal cells in hippocampal CA1 region. Adult bone marrow mesenchymal stem cells injected by intravenous administration show potential therapeutic effects in cognitive decline associated with stress-related lesions.

  9. Vascular endothelial cell membranes differentiate between stretch and shear stress through transitions in their lipid phases.

    Science.gov (United States)

    Yamamoto, Kimiko; Ando, Joji

    2015-10-01

    Vascular endothelial cells (ECs) respond to the hemodynamic forces stretch and shear stress by altering their morphology, functions, and gene expression. However, how they sense and differentiate between these two forces has remained unknown. Here we report that the plasma membrane itself differentiates between stretch and shear stress by undergoing transitions in its lipid phases. Uniaxial stretching and hypotonic swelling increased the lipid order of human pulmonary artery EC plasma membranes, thereby causing a transition from the liquid-disordered phase to the liquid-ordered phase in some areas, along with a decrease in membrane fluidity. In contrast, shear stress decreased the membrane lipid order and increased membrane fluidity. A similar increase in lipid order occurred when the artificial lipid bilayer membranes of giant unilamellar vesicles were stretched by hypotonic swelling, indicating that this is a physical phenomenon. The cholesterol content of EC plasma membranes significantly increased in response to stretch but clearly decreased in response to shear stress. Blocking these changes in the membrane lipid order by depleting membrane cholesterol with methyl-β-cyclodextrin or by adding cholesterol resulted in a marked inhibition of the EC response specific to stretch and shear stress, i.e., phosphorylation of PDGF receptors and phosphorylation of VEGF receptors, respectively. These findings indicate that EC plasma membranes differently respond to stretch and shear stress by changing their lipid order, fluidity, and cholesterol content in opposite directions and that these changes in membrane physical properties are involved in the mechanotransduction that activates membrane receptors specific to each force.

  10. Roe Protein Hydrolysates of Giant Grouper (Epinephelus lanceolatus Inhibit Cell Proliferation of Oral Cancer Cells Involving Apoptosis and Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Jing-Iong Yang

    2016-01-01

    Full Text Available Roe protein hydrolysates were reported to have antioxidant property but the anticancer effects were less addressed, especially for oral cancer. In this study, we firstly used the ultrafiltrated roe hydrolysates (URH derived from giant grouper (Epinephelus lanceolatus to evaluate the impact of URH on proliferation against oral cancer cells. We found that URH dose-responsively reduced cell viability of two oral cancer cells (Ca9-22 and CAL 27 in terms of ATP assay. Using flow cytometry, URH-induced apoptosis of Ca9-22 cells was validated by morphological features of apoptosis, sub-G1 accumulation, and annexin V staining in dose-responsive manners. URH also induced oxidative stress in Ca9-22 cells in terms of reactive oxygen species (ROS/superoxide generations and mitochondrial depolarization. Taken together, these data suggest that URH is a potential natural product for antioral cancer therapy.

  11. Cationic polystyrene nanospheres induce autophagic cell death through the induction of endoplasmic reticulum stress

    Science.gov (United States)

    Chiu, Hui-Wen; Xia, Tian; Lee, Yu-Hsuan; Chen, Chun-Wan; Tsai, Jui-Chen; Wang, Ying-Jan

    2014-12-01

    Nanoparticles (NPs) have been used to produce a wide range of products that have applications in imaging and drug delivery in medicine. Due to their chemical stability, well-controlled sizes and surface charges, polystyrene (PS) NPs have been developed as biosensors and drug delivery carriers. However, the possible adverse biological effects and underlying mechanisms are still unclear. Recently, autophagy has been implicated in the regulation of cell death. In this study, we evaluated a library of PS NPs with different surface charges. We found that NH2-labeled polystyrene (NH2-PS) nanospheres were highly toxic with enhanced uptake in macrophage (RAW 264.7) and lung epithelial (BEAS-2B) cells. Furthermore, NH2-PS could induce autophagic cell death. NH2-PS increased autophagic flux due to reactive oxygen species (ROS) generation and endoplasmic reticulum (ER) stress caused by misfolded protein aggregation. The inhibition of ER stress decreased cytotoxicity and autophagy in the NH2-PS-treated cells. In addition, the Akt/mTOR and AMPK signaling pathways were involved in the regulation of NH2-PS-triggered autophagic cell death. These results suggest an important role of autophagy in cationic NP-induced cell death and provide mechanistic insights into the inhibition of the toxicity and safe material design.Nanoparticles (NPs) have been used to produce a wide range of products that have applications in imaging and drug delivery in medicine. Due to their chemical stability, well-controlled sizes and surface charges, polystyrene (PS) NPs have been developed as biosensors and drug delivery carriers. However, the possible adverse biological effects and underlying mechanisms are still unclear. Recently, autophagy has been implicated in the regulation of cell death. In this study, we evaluated a library of PS NPs with different surface charges. We found that NH2-labeled polystyrene (NH2-PS) nanospheres were highly toxic with enhanced uptake in macrophage (RAW 264.7) and lung

  12. Optogenetically enhanced pituitary corticotroph cell activity post-stress onset causes rapid organizing effects on behaviour

    Science.gov (United States)

    De Marco, Rodrigo J.; Thiemann, Theresa; Groneberg, Antonia H.; Herget, Ulrich; Ryu, Soojin

    2016-01-01

    The anterior pituitary is the major link between nervous and hormonal systems, which allow the brain to generate adequate and flexible behaviour. Here, we address its role in mediating behavioural adjustments that aid in coping with acutely threatening environments. For this we combine optogenetic manipulation of pituitary corticotroph cells in larval zebrafish with newly developed assays for measuring goal-directed actions in very short timescales. Our results reveal modulatory actions of corticotroph cell activity on locomotion, avoidance behaviours and stimulus responsiveness directly after the onset of stress. Altogether, the findings uncover the significance of endocrine pituitary cells for rapidly optimizing behaviour in local antagonistic environments. PMID:27646867

  13. Epithelial Cell Transforming 2 and Aurora Kinase B Modulate Formation of Stress Granule-Containing Transcripts from Diverse Cellular Pathways in Astrocytoma Cells.

    Science.gov (United States)

    Weeks, Adrienne; Agnihotri, Sameer; Lymer, Jennifer; Chalil, Alan; Diaz, Roberto; Isik, Semra; Smith, Christian; Rutka, James T

    2016-06-01

    Stress granules are small RNA-protein granules that modify the translational landscape during cellular stress to promote survival. The RhoGTPase RhoA is implicated in the formation of RNA stress granules. Our data demonstrate that the cytokinetic proteins epithelial cell transforming 2 and Aurora kinase B (AurkB) are localized to stress granules in human astrocytoma cells. AurkB and its downstream target histone-3 are phosphorylated during arsenite-induced stress. Chemical (AZD1152-HQPA) and siRNA inhibition of AurkB results in fewer and smaller stress granules when analyzed using high-throughput fluorescent-based cellomics assays. RNA immunoprecipitation with the known stress granule aggregates TIAR and G3BP1 was performed on astrocytoma cells, and subsequent analysis revealed that astrocytoma stress granules harbor unique mRNAs for various cellular pathways, including cellular migration, metabolism, translation, and transcriptional regulation. Human astrocytoma cell stress granules contain mRNAs that are known to be involved in glioma signaling and the mammalian target of rapamycin pathway. These data provide evidence that RNA stress granules are a novel form of epigenetic regulation in astrocytoma cells, which may be targetable by chemical inhibitors and enhance astrocytoma susceptibility to conventional therapy, such as radiation and chemotherapy. PMID:27106762

  14. The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

  15. Sodium Butyrate Induces Endoplasmic Reticulum Stress and Autophagy in Colorectal Cells: Implications for Apoptosis.

    Directory of Open Access Journals (Sweden)

    Jintao Zhang

    Full Text Available Butyrate, a short-chain fatty acid derived from dietary fiber, inhibits proliferation and induces cell death in colorectal cancer cells. However, clinical trials have shown mixed results regarding the anti-tumor activities of butyrate. We have previously shown that sodium butyrate increases endoplasmic reticulum stress by altering intracellular calcium levels, a well-known autophagy trigger. Here, we investigated whether sodium butyrate-induced endoplasmic reticulum stress mediated autophagy, and whether there was crosstalk between autophagy and the sodium butyrate-induced apoptotic response in human colorectal cancer cells.Human colorectal cancer cell lines (HCT-116 and HT-29 were treated with sodium butyrate at concentrations ranging from 0.5-5mM. Cell proliferation was assessed using MTT tetrazolium salt formation. Autophagy induction was confirmed through a combination of Western blotting for associated proteins, acridine orange staining for acidic vesicles, detection of autolysosomes (MDC staining, and electron microscopy. Apoptosis was quantified by flow cytometry using standard annexinV/propidium iodide staining and by assessing PARP-1 cleavage by Western blot.Sodium butyrate suppressed colorectal cancer cell proliferation, induced autophagy, and resulted in apoptotic cell death. The induction of autophagy was supported by the accumulation of acidic vesicular organelles and autolysosomes, and the expression of autophagy-associated proteins, including microtubule-associated protein II light chain 3 (LC3-II, beclin-1, and autophagocytosis-associated protein (Atg3. The autophagy inhibitors 3-methyladenine (3-MA and chloroquine inhibited sodium butyrate induced autophagy. Furthermore, sodium butyrate treatment markedly enhanced the expression of endoplasmic reticulum stress-associated proteins, including BIP, CHOP, PDI, and IRE-1a. When endoplasmic reticulum stress was inhibited by pharmacological (cycloheximide and mithramycin and genetic

  16. Flow rate dependency of critical wall shear stress in a radial-flow cell

    DEFF Research Database (Denmark)

    Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.;

    2009-01-01

    In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersion...... of a water or ethanol suspension of starch granules on the surfaces. Depending on the substrate and on the suspending liquid, the aggregates differed in size and shape. Aggregate removal was studied at two flow rates. At the lower flow rate (Re-inlet = 955), the values of critical wall shear stress...

  17. Cell-free DNA in the Cerebrospinal Fluid under Emotional Stress

    OpenAIRE

    Mariia Zharova; Pavel Umriukhin; Natalia Veiko

    2016-01-01

    Background: Cell free circulating DNA (cfDNA) in blood is known to be a tumor marker however there is no information about its concentration in cerebrospinal fluid (CSF) in control and in emotional stress (ES). The aim of the study was to determine level of cfDNA in CSF of rats with different resistance to stress before and after ES. Methods: A total of 19 male Wistar rats weighing 200-220 g were included in this study. All rats were divided into 2 groups depending on the motor activity: acti...

  18. Mitochondria are targets for peroxisome-derived oxidative stress in cultured mammalian cells.

    Science.gov (United States)

    Wang, Bo; Van Veldhoven, Paul P; Brees, Chantal; Rubio, Noemí; Nordgren, Marcus; Apanasets, Oksana; Kunze, Markus; Baes, Myriam; Agostinis, Patrizia; Fransen, Marc

    2013-12-01

    Many cellular processes are driven by spatially and temporally regulated redox-dependent signaling events. Although mounting evidence indicates that organelles such as the endoplasmic reticulum and mitochondria can function as signaling platforms for oxidative stress-regulated pathways, little is known about the role of peroxisomes in these processes. In this study, we employ targeted variants of the genetically encoded photosensitizer KillerRed to gain a better insight into the interplay between peroxisomes and cellular oxidative stress. We show that the phototoxic effects of peroxisomal KillerRed induce mitochondria-mediated cell death and that this process can be counteracted by targeted overexpression of a select set of antioxidant enzymes, including peroxisomal glutathione S-transferase kappa 1, superoxide dismutase 1, and mitochondrial catalase. We also present evidence that peroxisomal disease cell lines deficient in plasmalogen biosynthesis or peroxisome assembly are more sensitive to KillerRed-induced oxidative stress than control cells. Collectively, these findings confirm and extend previous observations suggesting that disturbances in peroxisomal redox control and metabolism can sensitize cells to oxidative stress. In addition, they lend strong support to the ideas that peroxisomes and mitochondria share a redox-sensitive relationship and that the redox communication between these organelles is not only mediated by diffusion of reactive oxygen species from one compartment to the other. Finally, these findings indicate that mitochondria may act as dynamic receivers, integrators, and transmitters of peroxisome-derived mediators of oxidative stress, and this may have profound implications for our views on cellular aging and age-related diseases.

  19. The neuroprotective properties of palmitoylethanolamine against oxidative stress in a neuronal cell line

    Directory of Open Access Journals (Sweden)

    Chapman Kent D

    2009-12-01

    Full Text Available Abstract Background N-acylethanolamines (NAEs are lipids upregulated in response to cell and tissue injury and are involved in cytoprotection. Arachidonylethanolamide (AEA is a well characterized NAE that is an endogenous ligand at cannabinoid and vanilloid receptors, but it exists in small quantities relative to other NAE types. The abundance of other NAE species, such as palmitoylethanolamine (PEA, together with their largely unknown function and receptors, has prompted us to examine the neuroprotective properties and mechanism of action of PEA. We hypothesized that PEA protects HT22 cells from oxidative stress and activates neuroprotective kinase signaling pathways. Results Indeed PEA protected HT22 cells from oxidative stress in part by mediating an increase in phosphorylated Akt (pAkt and ERK1/2 immunoreactivity as well as pAkt nuclear translocation. These changes take place within a time frame consistent with neuroprotection. Furthermore, we determined that changes in pAkt immunoreactivity elicited by PEA were not mediated by activation of cannabinoid receptor type 2 (CB2, thus indicating a novel mechanism of action. These results establish a role for PEA as a neuroprotectant against oxidative stress, which occurs in a variety of neurodegenerative diseases. Conclusions The results from this study reveal that PEA protects HT22 cells from oxidative stress and alters the localization and expression levels of kinases known to be involved in neuroprotection by a novel mechanism. Overall, these results identify PEA as a neuroprotectant with potential as a possible therapeutic agent in neurodegenerative diseases involving oxidative stress.

  20. Latin America multidisciplinary research on heat shock proteins and cell stress: proceedings of the first conference of the Latin America Chapter of the Cell Stress Society International.

    Science.gov (United States)

    Bausero, María A

    2015-09-01

    The First Conference of the Latin America Chapter of the Cell Stress Society International (CSSI) organized by CSSI was held in Montevideo, Uruguay, on March 11-14, 2014. The Latin America Chapter of the CSSI (LAC-CSSI) was established at the Workshop on the Molecular Biology of the Stress Response, Porto Alegre, Brazil, May 2012. The chapter's first meeting took place in the beautiful city of Montevideo and was chaired by the first (LAC-CSSI) elected president Professor María Bausero. Forty-two invited speakers presented their work to more than 100 scientists. The first day of the conference was dedicated to an introductory program for students, young investigators, and participants new to the field of molecular chaperones and the stress response. These seminars were held in the Pasteur Institute of Montevideo and the Faculty of Sciences of the University of the Republic. These institutions were carefully selected to give foreign participants a broad view of the diversity of students and institutions doing research in Uruguay, as well as an opportunity for direct interaction with our scientists and students. Invited speakers for the seminar series were Dr. Wolfgang Schumann, Dr. Cristina Bonorino, Dr. Antonio De Maio, Dr. Ian Brown, Dr. Rafael Radi, Dr. Daniel Ciocca, and Dr. Celia Quijano. The remaining days of the conference took place at the Sheraton Hotel in Montevideo, and the scientific sessions are discussed below.

  1. Airborne Fine Particulate Matter Induces Oxidative Stress and Inflammation in Human Nasal Epithelial Cells.

    Science.gov (United States)

    Hong, Zhicong; Guo, Zhiqiang; Zhang, Ruxin; Xu, Jian; Dong, Weiyang; Zhuang, Guoshun; Deng, Congrui

    2016-01-01

    Airborne fine particulate matter with an aerodynamic diameter equal to or smaller than 2.5 μm is abbreviated as PM2.5, which is one of the main components in air pollution. Exposure to PM2.5 is associated with increased risk of many human diseases, including chronic and allergic rhinitis, but the underlying molecular mechanism for its toxicity has not been fully elucidated. We have hypothesized that PM2.5 may cause oxidative stress and enhance inflammatory responses in nasal epithelial cells. Accordingly, we used human RPMI 2650 cells, derived from squamous cell carcinoma of the nasal septum, as a model of nasal epithelial cells, and exposed them to PM2.5 that was collected at Fudan University (31.3°N, 121.5°E) in Shanghai, China. PM2.5 exposure decreased the viability of RPMI 2650 cells, suggesting that PM2.5 may impair the barrier function of nasal epithelial cells. Moreover, PM2.5 increased the levels of intracellular reactive oxygen species (ROS) and the nuclear translocation of NF-E2-related factor-2 (Nrf2). Importantly, PM2.5 also decreased the activities of superoxide dismutase, catalase and glutathione peroxidase. Pretreatment with N-Acetyl-L-cysteine (an anti-oxidant) reduced the degree of the PM2.5-induced oxidative stress in RPMI 2650 cells. In addition, PM2.5 increased the production of granulocyte-macrophage colony-stimulating factor, tumor necrosis factor-α, interleukin-13 and eotaxin (C-C motif chemokine ligand 11), each of which initiates and/or augments local inflammation. These results suggest that PM2.5 may induce oxidative stress and inflammatory responses in human nasal epithelial cells, thereby leading to nasal inflammatory diseases. The present study provides insights into cellular injury induced by PM2.5.

  2. Methylglyoxal induces cell death through endoplasmic reticulum stress-associated ROS production and mitochondrial dysfunction.

    Science.gov (United States)

    Chan, Chi-Ming; Huang, Duen-Yi; Huang, Yi-Pin; Hsu, Shu-Hao; Kang, Lan-Ya; Shen, Chung-Min; Lin, Wan-Wan

    2016-09-01

    Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are two important leading causes of acquired blindness in developed countries. As accumulation of advanced glycation end products (AGEs) in retinal pigment epithelial (RPE) cells plays an important role in both DR and AMD, and the methylglyoxal (MGO) within the AGEs exerts irreversible effects on protein structure and function, it is crucial to understand the underlying mechanism of MGO-induced RPE cell death. Using ARPE-19 as the cell model, this study revealed that MGO induces RPE cell death through a caspase-independent manner, which relying on reactive oxygen species (ROS) formation, mitochondrial membrane potential (MMP) loss, intracellular calcium elevation and endoplasmic reticulum (ER) stress response. Suppression of ROS generation can reverse the MGO-induced ROS production, MMP loss, intracellular calcium increase and cell death. Moreover, store-operated calcium channel inhibitors MRS1845 and YM-58483, but not the inositol 1,4,5-trisphosphate (IP3) receptor inhibitor xestospongin C, can block MGO-induced ROS production, MMP loss and sustained intracellular calcium increase in ARPE-19 cells. Lastly, inhibition of ER stress by salubrinal and 4-PBA can reduce the MGO-induced intracellular events and cell death. Therefore, our data indicate that MGO can decrease RPE cell viability, resulting from the ER stress-dependent intracellular ROS production, MMP loss and increased intracellular calcium increase. As MGO is one of the components of drusen in AMD and is the AGEs adduct in DR, this study could provide a valuable insight into the molecular pathogenesis and therapeutic intervention of AMD and DR. PMID:27307396

  3. In vitro toxicity of nanosized copper particles in PC12 cells induced by oxidative stress

    Energy Technology Data Exchange (ETDEWEB)

    Xu Pengjuan; Xu Jing; Liu Shichang [Nankai University, College of Medicine (China); Ren, Guogang [University of Hertfordshire, School of Aerospace Engineering (United Kingdom); Yang Zhuo, E-mail: zhuoyang@nankai.edu.cn [Nankai University, College of Medicine (China)

    2012-06-15

    Recent evidence suggests that some nanomaterials, which are widely used in many fields, have health effects. In order to investigate the cytotoxicity induced by nanosized copper particles (nano-Cu), PC12 cells, which were widely used as an in vitro model for the neuron research, were treated with different concentrations (0, 1, 10, 30, and 100 {mu}g/mL) of nano-Cu. The cell viability was determined by measurement of the reduction product of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). The oxidative stress induced by nano-Cu and its possible mechanism were studied in relation to the generation of reactive oxygen species (ROS) and the cellular activity of superoxide dismutase (SOD). Results showed that incubation of PC12 cells with increasing concentrations of nano-Cu induced a decrease of cell viability in a concentration- and time-dependent manner. In addition, flow cytometry assay using Annexin V-FITC/PI staining was used to investigate the mode of nano-Cu-induced cell death and quantified the percentage of apoptotic cells. Results showed that nano-Cu induced the significant apoptosis in PC12 cells. Meanwhile, intracellular accumulation of ROS was increased with the increased concentrations of nano-Cu and it was associated with decreased SOD activity, which was probably due to protect effects against the oxidative stress in PC12 cells. Results suggested that both excessive intracellular ROS and decreased SOD contributed to nano-Cu-induced cytotoxicity. In other words, the increasing of oxidative stress was a key mechanism in PC12 apoptosis induced by nano-Cu.

  4. Microscopic analysis of cell death by metabolic stress-induced autophagy in prostate cancer

    Science.gov (United States)

    Changou, Chun; Cheng, R. Holland; Bold, Richard; Kung, Hsing-Jien; Chuang, Frank Y. S.

    2013-02-01

    Autophagy is an intracellular recycling mechanism that helps cells to survive against environmental stress and nutritional starvation. We have recently shown that prostate cancers undergo metabolic stress and caspase-independent cell death following exposure to arginine deiminase (ADI, an enzyme that degrades arginine in tissue). The aims of our current investigation into the application of ADI as a novel cancer therapy are to identify the components mediating tumor cell death, and to determine the role of autophagy (stimulated by ADI and/or rapamycin) on cell death. Using advanced fluorescence microscopy techniques including 3D deconvolution and superresolution structured-illumination microscopy (SIM), we show that prostate tumor cells that are killed after exposure to ADI for extended periods, exhibit a morphology that is distinct from caspase-dependent apoptosis; and that autophagosomes forming as a result of ADI stimulation contain DAPI-stained nuclear material. Fluorescence imaging (as well as cryo-electron microscopy) show a breakdown of both the inner and outer nuclear membranes at the interface between the cell nucleus and aggregated autophagolysosomes. Finally, the addition of N-acetyl cysteine (or NAC, a scavenger for reactive oxygen species) effectively abolishes the appearance of autophagolysosomes containing nuclear material. We hope to continue this research to understand the processes that govern the survival or death of these tumor cells, in order to develop methods to improve the efficacy of cancer pharmacotherapy.

  5. Selective induction of oxidative stress in cancer cells via synergistic combinations of agents targeting redox homeostasis.

    Science.gov (United States)

    Akladios, Fady N; Andrew, Scott D; Parkinson, Christopher J

    2015-07-01

    Cancer cell resistance to chemotherapy is still a heavy burden that impairs the response of many cancer patients to conventional chemotherapy. Using drug combinations is one therapeutic approach to overcome the developing resistance to any one drug. Oxidative stress is now a generally regarded hallmark of cancer that can be one approach to selectively target cancer cells while sparing normal cells. With the aim of increasing oxidative stress in cancer cells to a lethal set point, we have generated and combined several series of redox active compounds that act at different points of the cellular oxidative cascade. The premise of such combinations is to deplete of endogenous antioxidant defence proteins (e.g., Glutathione) while concomitantly increasing the generation of ROS via metal redox recycling and Fenton chemistry which eventually leads to the disruption of cellular redox homeostasis and induction of cell death. Through this approach, we have identified highly synergistic combinations of two distinctive classes of compounds (Azines and Copper(II) complexes of 2-pyridyl ketone thiosemicarbazones) which are capable of eliminating cancer cells without concomitant increase in toxicity toward normal cells. In one of our most potent combinations, a combination index (CI) value of 0.056 was observed, representing a 17 fold enhancement in activity beyond additive effects. Such new combination regimen of redox active compounds can be one step closer to potentially safer low dose chemotherapy. PMID:26022081

  6. On-Chip Quantitative Measurement of Mechanical Stresses During Cell Migration with Emulsion Droplets

    Science.gov (United States)

    Molino, D.; Quignard, S.; Gruget, C.; Pincet, F.; Chen, Y.; Piel, M.; Fattaccioli, J.

    2016-07-01

    The ability of immune cells to migrate within narrow and crowded spaces is a critical feature involved in various physiological processes from immune response to metastasis. Several in-vitro techniques have been developed so far to study the behaviour of migrating cells, the most recent being based on the fabrication of microchannels within which cells move. To address the question of the mechanical stress a cell is able to produce during the encounter of an obstacle while migrating, we developed a hybrid microchip made of parallel PDMS channels in which oil droplets are sparsely distributed and serve as deformable obstacles. We thus show that cells strongly deform droplets while passing them. Then, we show that the microdevice can be used to study the influence of drugs on migration at the population level. Finally, we describe a quantitative analysis method of the droplet deformation that allows measuring in real-time the mechanical stress exerted by a single cell. The method presented herein thus constitutes a powerful analytical tool for cell migration studies under confinement.

  7. On-Chip Quantitative Measurement of Mechanical Stresses During Cell Migration with Emulsion Droplets

    Science.gov (United States)

    Molino, D.; Quignard, S.; Gruget, C.; Pincet, F.; Chen, Y.; Piel, M.; Fattaccioli, J.

    2016-01-01

    The ability of immune cells to migrate within narrow and crowded spaces is a critical feature involved in various physiological processes from immune response to metastasis. Several in-vitro techniques have been developed so far to study the behaviour of migrating cells, the most recent being based on the fabrication of microchannels within which cells move. To address the question of the mechanical stress a cell is able to produce during the encounter of an obstacle while migrating, we developed a hybrid microchip made of parallel PDMS channels in which oil droplets are sparsely distributed and serve as deformable obstacles. We thus show that cells strongly deform droplets while passing them. Then, we show that the microdevice can be used to study the influence of drugs on migration at the population level. Finally, we describe a quantitative analysis method of the droplet deformation that allows measuring in real-time the mechanical stress exerted by a single cell. The method presented herein thus constitutes a powerful analytical tool for cell migration studies under confinement. PMID:27373558

  8. IQ domain GTPase-activating protein 1 is involved in shear stress-induced progenitor-derived endothelial cell alignment.

    Directory of Open Access Journals (Sweden)

    Lila Rami

    Full Text Available Shear stress is one of mechanical constraints which are exerted by blood flow on endothelial cells (ECs. To adapt to shear stress, ECs align in the direction of flow through adherens junction (AJ remodeling. However, mechanisms regulating ECs alignment under shear stress are poorly understood. The scaffold protein IQ domain GTPase activating protein 1 (IQGAP1 is a scaffold protein which couples cell signaling to the actin and microtubule cytoskeletons and is involved in cell migration and adhesion. IQGAP1 also plays a role in AJ organization in epithelial cells. In this study, we investigated the potential IQGAP1 involvement in the endothelial cells alignment under shear stress. Progenitor-derived endothelial cells (PDECs, transfected (or not with IQGAP1 small interfering RNA, were exposed to a laminar shear stress (1.2 N/m(2 and AJ proteins (VE-cadherin and β-catenin and IQGAP1 were labeled by immunofluorescence. We show that IQGAP1 is essential for ECs alignment under shear stress. We studied the role of IQGAP1 in AJs remodeling of PDECs exposed to shear stress by studying cell localization and IQGAP1 interactions with VE-cadherin and β-catenin by immunofluorescence and Proximity Ligation Assays. In static conditions, IQGAP1 interacts with VE-cadherin but not with β-catenin at the cell membrane. Under shear stress, IQGAP1 lost its interaction from VE-cadherin to β-catenin. This "switch" was concomitant with the loss of β-catenin/VE-cadherin interaction at the cell membrane. This work shows that IQGAP1 is essential to ECs alignment under shear stress and that AJ remodeling represents one of the mechanisms involved. These results provide a new approach to understand ECs alignment under to shear stress.

  9. IQ Domain GTPase-Activating Protein 1 is Involved in Shear Stress-Induced Progenitor-Derived Endothelial Cell Alignment

    Science.gov (United States)

    Rami, Lila; Auguste, Patrick; Thebaud, Noélie B.; Bareille, Reine; Daculsi, Richard; Ripoche, Jean; Bordenave, Laurence

    2013-01-01

    Shear stress is one of mechanical constraints which are exerted by blood flow on endothelial cells (ECs). To adapt to shear stress, ECs align in the direction of flow through adherens junction (AJ) remodeling. However, mechanisms regulating ECs alignment under shear stress are poorly understood. The scaffold protein IQ domain GTPase activating protein 1 (IQGAP1) is a scaffold protein which couples cell signaling to the actin and microtubule cytoskeletons and is involved in cell migration and adhesion. IQGAP1 also plays a role in AJ organization in epithelial cells. In this study, we investigated the potential IQGAP1 involvement in the endothelial cells alignment under shear stress. Progenitor-derived endothelial cells (PDECs), transfected (or not) with IQGAP1 small interfering RNA, were exposed to a laminar shear stress (1.2 N/m2) and AJ proteins (VE-cadherin and β-catenin) and IQGAP1 were labeled by immunofluorescence. We show that IQGAP1 is essential for ECs alignment under shear stress. We studied the role of IQGAP1 in AJs remodeling of PDECs exposed to shear stress by studying cell localization and IQGAP1 interactions with VE-cadherin and β-catenin by immunofluorescence and Proximity Ligation Assays. In static conditions, IQGAP1 interacts with VE-cadherin but not with β-catenin at the cell membrane. Under shear stress, IQGAP1 lost its interaction from VE-cadherin to β-catenin. This “switch” was concomitant with the loss of β-catenin/VE-cadherin interaction at the cell membrane. This work shows that IQGAP1 is essential to ECs alignment under shear stress and that AJ remodeling represents one of the mechanisms involved. These results provide a new approach to understand ECs alignment under to shear stress. PMID:24278215

  10. The Plant Cell Wall: A Complex and Dynamic Structure As Revealed by the Responses of Genes under Stress Conditions.

    Science.gov (United States)

    Houston, Kelly; Tucker, Matthew R; Chowdhury, Jamil; Shirley, Neil; Little, Alan

    2016-01-01

    The plant cell wall has a diversity of functions. It provides a structural framework to support plant growth and acts as the first line of defense when the plant encounters pathogens. The cell wall must also retain some flexibility, such that when subjected to developmental, biotic, or abiotic stimuli it can be rapidly remodeled in response. Genes encoding enzymes capable of synthesizing or hydrolyzing components of the plant cell wall show differential expression when subjected to different stresses, suggesting they may facilitate stress tolerance through changes in cell wall composition. In this review we summarize recent genetic and transcriptomic data from the literature supporting a role for specific cell wall-related genes in stress responses, in both dicot and monocot systems. These studies highlight that the molecular signatures of cell wall modification are often complex and dynamic, with multiple genes appearing to respond to a given stimulus. Despite this, comparisons between publically available datasets indicate that in many instances cell wall-related genes respond similarly to different pathogens and abiotic stresses, even across the monocot-dicot boundary. We propose that the emerging picture of cell wall remodeling during stress is one that utilizes a common toolkit of cell wall-related genes, multiple modifications to cell wall structure, and a defined set of stress-responsive transcription factors that regulate them. PMID:27559336

  11. The Plant Cell Wall: A Complex and Dynamic Structure As Revealed by the Responses of Genes under Stress Conditions

    Science.gov (United States)

    Houston, Kelly; Tucker, Matthew R.; Chowdhury, Jamil; Shirley, Neil; Little, Alan

    2016-01-01

    The plant cell wall has a diversity of functions. It provides a structural framework to support plant growth and acts as the first line of defense when the plant encounters pathogens. The cell wall must also retain some flexibility, such that when subjected to developmental, biotic, or abiotic stimuli it can be rapidly remodeled in response. Genes encoding enzymes capable of synthesizing or hydrolyzing components of the plant cell wall show differential expression when subjected to different stresses, suggesting they may facilitate stress tolerance through changes in cell wall composition. In this review we summarize recent genetic and transcriptomic data from the literature supporting a role for specific cell wall-related genes in stress responses, in both dicot and monocot systems. These studies highlight that the molecular signatures of cell wall modification are often complex and dynamic, with multiple genes appearing to respond to a given stimulus. Despite this, comparisons between publically available datasets indicate that in many instances cell wall-related genes respond similarly to different pathogens and abiotic stresses, even across the monocot-dicot boundary. We propose that the emerging picture of cell wall remodeling during stress is one that utilizes a common toolkit of cell wall-related genes, multiple modifications to cell wall structure, and a defined set of stress-responsive transcription factors that regulate them. PMID:27559336

  12. Elastic hydrogel as a sensor for detection of mechanical stress generated by single cells grown in three-dimensional environment.

    Science.gov (United States)

    Huang, Jianyong; Wang, Liangli; Xiong, Chunyang; Yuan, Fan

    2016-08-01

    Cell volume growth occurs in all living tissues. The growth exerts mechanical stresses on surrounding tissues that may alter tissue microenvironment, and have significant implications in health and diseases. However, the level of growth stress generated by single cells in three-dimensional (3D) environment remains to be determined. To this end, we developed a growth force microscopy technique to determine 3D distribution of the stress. The technique was based on encapsulation of cells in elastic hydrogels, and involved 3D particle tracking and mechanical analysis of gel deformation. Data from the study demonstrated that the growth stress was dynamic, and the stress distribution at the gel-cell interface was correlated inversely to the mean surface curvature or the distance to the geometric center of the cell. The stress averaged over the cell surface increased with increasing gel stiffness, suggesting that cells could alter growth stress in response to stiffness change in microenvironment. These findings suggested that the elastic hydrogel-based microscopy technique had a potential to provide new insights into mechanisms of mechanical interactions between cell and its microenvironment. PMID:27182812

  13. Combinations of Ashwagandha leaf extracts protect brain-derived cells against oxidative stress and induce differentiation.

    Directory of Open Access Journals (Sweden)

    Navjot Shah

    Full Text Available Ashwagandha, a traditional Indian herb, has been known for its variety of therapeutic activities. We earlier demonstrated anticancer activities in the alcoholic and water extracts of the leaves that were mediated by activation of tumor suppressor functions and oxidative stress in cancer cells. Low doses of these extracts were shown to possess neuroprotective activities in vitro and in vivo assays.We used cultured glioblastoma and neuroblastoma cells to examine the effect of extracts (alcoholic and water as well as their bioactive components for neuroprotective activities against oxidative stress. Various biochemical and imaging assays on the marker proteins of glial and neuronal cells were performed along with their survival profiles in control, stressed and recovered conditions. We found that the extracts and one of the purified components, withanone, when used at a low dose, protected the glial and neuronal cells from oxidative as well as glutamate insult, and induced their differentiation per se. Furthermore, the combinations of extracts and active component were highly potent endorsing the therapeutic merit of the combinational approach.Ashwagandha leaf derived bioactive compounds have neuroprotective potential and may serve as supplement for brain health.

  14. Green tea polyphenol epigallocatechin-3-gallate differentially modulates oxidative stress in PC12 cell compartments

    International Nuclear Information System (INIS)

    Tea polyphenols have been reported to be potent antioxidants and beneficial in oxidative stress related diseases. Prooxidant effects of tea polyphenols have also been reported in cell culture systems. In the present study, we have studied oxidative stress in the subcellular compartments of PC12 cells after treatment with different concentrations of the green tea polyphenol, epigallocatechin-3-gallate (EGCG). We have demonstrated that EGCG has differentially affected the production of reactive oxygen species (ROS), glutathione (GSH) metabolism and cytochrome P450 2E1 activity in the different subcellular compartments in PC12 cells. Our results have shown that although the cell survival was not inhibited by EGCG, there was, however, an increased DNA breakdown and activation of apoptotic markers, caspase 3 and poly- (ADP-ribose) polymerase (PARP) at higher concentrations of EGCG treatment. Our results suggest that the differential effects of EGCG might be related to the alterations in oxidative stress, GSH pools and CYP2E1 activity in different cellular compartments. These results may have implications in determining the chemopreventive therapeutic use of tea polyphenols in vivo

  15. JNK and NADPH Oxidase Involved in Fluoride-Induced Oxidative Stress in BV-2 Microglia Cells

    Directory of Open Access Journals (Sweden)

    Ling Yan

    2013-01-01

    Full Text Available Excessive fluoride may cause central nervous system (CNS dysfunction, and oxidative stress is a recognized mode of action of fluoride toxicity. In CNS, activated microglial cells can release more reactive oxygen species (ROS, and NADPH oxidase (NOX is the major enzyme for the production of extracellular superoxide in microglia. ROS have been characterized as an important secondary messenger and modulator for various mammalian intracellular signaling pathways, including the MAPK pathways. In this study we examined ROS production and TNF-α, IL-1β inflammatory cytokines releasing, and the expression of MAPKs in BV-2 microglia cells treated with fluoride. We found that fluoride increased JNK phosphorylation level of BV-2 cells and pretreatment with JNK inhibitor SP600125 markedly reduced the levels of intracellular and NO. NOX inhibitor apocynin and iNOS inhibitor SMT dramatically decreased NaF-induced ROS and NO generations, respectively. Antioxidant melatonin (MEL resulted in a reduction in JNK phosphorylation in fluoride-stimulated BV-2 microglia. The results confirmed that NOX and iNOS played an important role in fluoride inducing oxidative stress and NO production and JNK took part in the oxidative stress induced by fluoride and meanwhile also could be activated by ROS in fluoride-treated BV-2 cells.

  16. Influence of doxorubicin on apoptosis and oxidative stress in breast cancer cell lines.

    Science.gov (United States)

    Pilco-Ferreto, Nesstor; Calaf, Gloria M

    2016-08-01

    Breast cancer is one of the leading causes of mortality among women worldwide due to aggressive behavior, early metastasis, resistance to existing chemotherapeutic agent and high mortality rate. Doxorubicin (Dox) is a powerful antitumoral drug. It is one of the most active agents for treatment of breast cancer. The aim of the present study was to evaluate the influence of Dox in apoptosis and oxidative stress in the breast cancer cell lines MCF-10F, MCF-7 and MDA-MB-231. These studies showed that Dox decreased anti-apoptotic Bcl-2 protein expression and affected oxidative stress by increasing hydrogen peroxide production and simultaneously decreasing NF-κB gene and protein expression in MCF-7, a tumorigenic triple-positive cell line. Results also indicated that Dox induced apoptosis by upregulating Bax, caspase-8 and caspase-3 and downregulation of Bcl-2 protein expression. On the contrary, ROS damage decreased by increasing SOD2 gene and protein expression and hydrogen peroxide production with parallel NF-κB protein expression decrease in MDA-MB-231, a tumorigenic triple-negative breast cancer cell line. It can be concluded that Dox activated apoptosis by inducing proteolytic processing of Bcl-2 family, caspases and simultaneously decreased oxidative stress by influencing ROS damage in MCF-7 and MDA-MB-231 cell lines. PMID:27278553

  17. Inhibition of stress mediated cell death by human lactate dehydrogenase B in yeast.

    Science.gov (United States)

    Sheibani, Sara; Jones, Natalie K; Eid, Rawan; Gharib, Nada; Arab, Nagla T T; Titorenko, Vladimir; Vali, Hojatollah; Young, Paul A; Greenwood, Michael T

    2015-08-01

    We report the identification of human L- lactate dehydrogenase B (LDHB) as a novel Bax suppressor. Yeast heterologously expressing LDHB is also resistant to the lethal effects of copper indicating that it is a general suppressor of stress mediated cell death. To identify potential LDHB targets, LDHB was expressed in yeast mutants defective in apoptosis, necrosis and autophagy. The absence of functional PCD regulators including MCA1, YBH3, cyclophilin (CPR3) and VMA3, as well as the absence of the pro-survival autophagic pathway (ATG1,7) did not interfere with the LDHB mediated protection against copper indicating that LDHB functions independently of known PCD regulators or by simply blocking or stimulating a common PCD promoting or inhibitory pathway. Measurements of lactate levels revealed that short-term copper stress (1.6 mM, 4 h), does not increase intracellular levels of lactate, instead a three-fold increase in extracellular lactate was observed. Thus, yeast cells resemble mammalian cells where different stresses are known to lead to increased lactate production leading to lactic acidosis. In agreement with this, we found that the addition of exogenous lactic acid to growth media was sufficient to induce cell death that could be inhibited by the expression of LDHB. Taken together our results suggest that lactate dehydrogenase is a general suppressor of PCD in yeast. PMID:26032856

  18. Influence de substrats organiques sur la cinétique bactérienne d'oxydation de l'arsenic III

    OpenAIRE

    Lescure, Tiffanie; Joulian, Catherine; Bauda, Pascale; Hénault, Catherine; Battaglia-Brunet, Fabienne

    2013-01-01

    La microflore des sols joue un rôle majeur dans le comportement des éléments métalliques et métalloïdes. Certaines bactéries sont ainsi capables d'oxyder l'AsIII en AsV, moins toxique et moins mobile. Des travaux effectués avec des bactéries AsIII-oxydantes dans le cadre de différents projets indiquent un effet très significatif de la matière organique sur l'activité de ces micro-organismes en aérobie. La matière organique apparaît comme ralentissant la transformation de l'AsIII en AsV par le...

  19. Etude des effets mitochondriaux du monoxyde d'azote :
    Régulation de l'oxydation phosphorylante et de la transition de perméabilité

    OpenAIRE

    Clerc, Pascaline

    2006-01-01

    Le monoxyde d'azote (NO) est formé à partir de L-arginine par la famille des NO synthases. La dysrégulation de la synthèse de cette molécule de signalisation cellulaire est impliquée dans le développement d'un grand nombre de pathologies. Les effets cellulaires du NO sont en partie dus à une inhibition des complexes de la chaîne respiratoire mitochondriale. Nous nous sommes intéressés aux effets du NO sur la régulation de l'oxydation phosphorylante et de le transition de perméabilité, deux pr...

  20. Induction of the major heat-stress protein in purified rat glial cells

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, R.N.; Dwyer, B.E.; Welch, W.; Cole, R.; de Vellis, J.; Liotta, K.

    1988-05-01

    Cultured purified oligodendroglia and astroglia exposed to heat stress (45 degrees C, 10 or 20 min) synthesized a 68-kDa heat-stress protein, which migrates on two-dimensional gel electrophoresis and reacts with a specific monoclonal antibody suggesting it is similar to a major 72-kDa heat-shock protein previously reported in other cell types. This protein was not detected in control glial cultures. Actinomycin D prevented synthesis of this protein demonstrating an absolute requirement for newly synthesized mRNA. The response was prolonged by increasing the period of heat stress from 10 to 20 min. In addition to the 68-kDa HSP protein, the incorporation of radioactivity into 70-, 89-, and 97-kDa proteins was also increased after heating, but in contrast to the 68 kDa protein these proteins appeared to be made in control glial cultures.

  1. The clinical relevance of cell-based therapy for the treatment of stress urinary incontinence

    DEFF Research Database (Denmark)

    Gräs, Søren; Lose, Gunnar

    2011-01-01

    Stress urinary incontinence is a common disorder affecting the quality of life for millions of women worldwide. Effective surgical procedures involving synthetic permanent meshes exist, but significant short- and long-term complications occur. Cell-based therapy using autologous stem cells or...... provided proof of concept for the idea. An initial enthusiasm caused by positive results from early clinical trials has been dampened by the recognition of scientific irregularities. At the same time, the safety issue for cell-based therapy has been highlighted by the appearance of new and comprehensive...... progenitor cells presents an alternative approach, which aims at repairing the anatomical components of the urethral continence mechanism. In vitro expanded progenitor cells isolated from muscle biopsies have been most intensely investigated, and both preclinical trials and a few clinical trials have...

  2. A review of adaptive mechanisms in cell responses towards oxidative stress caused by dental resin monomers.

    Science.gov (United States)

    Krifka, Stephanie; Spagnuolo, Gianrico; Schmalz, Gottfried; Schweikl, Helmut

    2013-06-01

    Dental composite resins are biomaterials commonly used to aesthetically restore the structure and function of teeth impaired by caries, erosion, or fracture. Residual monomers released from resin restorations as a result of incomplete polymerization processes interact with living oral tissues. Monomers like triethylene glycol dimethacrylate (TEGDMA) or 2-hydroxylethyl methacrylate (HEMA) are cytotoxic via apoptosis, induce genotoxic effects, and delay the cell cycle. Monomers also influence the response of cells of the innate immune system, inhibit specific odontoblast cell functions, or delay the odontogenic differentiation and mineralization processes in pulp-derived cells including stem cells. These observations indicate that resin monomers act as environmental stressors which inevitably disturb regulatory cellular networks through interference with signal transduction pathways. We hypothesize that an understanding of the cellular mechanisms underlying these phenomena will provide a better estimation of the consequences associated with dental therapy using composite materials, and lead to innovative therapeutic strategies and improved materials being used at tissue interfaces within the oral cavity. Current findings strongly suggest that monomers enhance the formation of reactive oxygen species (ROS), which is most likely the cause of biological reactions activated by dental composites and resin monomers. The aim of the present review manuscript is to discuss adaptive cell responses to oxidative stress caused by monomers. The particular significance of a tightly controlled network of non-enzymatic as well as enzymatic antioxidants for the regulation of cellular redox homeostasis and antioxidant defense in monomer-exposed cells will be addressed. The expression of ROS-metabolizing antioxidant enzymes like superoxide dismutase (SOD1), glutathione peroxidase (GPx1/2), and catalase in cells exposed to monomers will be discussed with particular emphasis on the role

  3. Mercury induces proliferation and reduces cell size in vascular smooth muscle cells through MAPK, oxidative stress and cyclooxygenase-2 pathways

    International Nuclear Information System (INIS)

    Mercury exposure is known to increase cardiovascular risk but the underlying cellular mechanisms remain undetermined. We analyzed whether chronic exposure to HgCl2 affects vascular structure and the functional properties of vascular smooth muscle cells (VSMC) through oxidative stress/cyclooxygenase-2 dependent pathways. Mesenteric resistance arteries and aortas from Wistar rats treated with HgCl2 (first dose 4.6 mg kg−1, subsequent doses 0.07 mg kg−1 day−1, 30 days) and cultured aortic VSMC stimulated with HgCl2 (0.05–5 μg/ml) were used. Treatment of rats with HgCl2 decreased wall thickness of the resistance and conductance vasculature, increased the number of SMC within the media and decreased SMC nucleus size. In VSMCs, exposure to HgCl2: 1) induced a proliferative response and a reduction in cell size; 2) increased superoxide anion production, NADPH oxidase activity, gene and/or protein levels of the NADPH oxidase subunit NOX-1, the EC- and Mn-superoxide dismutases and cyclooxygenase-2 (COX-2); 3) induced activation of ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized the proliferative response and the altered cell size induced by HgCl2. Blockade of ERK1/2 and p38 signaling pathways abolished the HgCl2-induced Nox1 and COX-2 expression and normalized the alterations induced by mercury in cell proliferation and size. In conclusion, long exposure of VSMC to low doses of mercury activates MAPK signaling pathways that result in activation of inflammatory proteins such as NADPH oxidase and COX-2 that in turn induce proliferation of VSMC and changes in cell size. These findings offer further evidence that mercury might be considered an environmental risk factor for cardiovascular disease. - Highlights: ► Chronic HgCl2 exposure induces vascular remodeling. ► HgCl2 induces proliferation and decreased cell size in vascular smooth muscle cells. ► HgCl2 induces MAPK activation, oxidative stress and COX-2 expression. ► Inhibition of

  4. Low-concentration uranium enters the HepG2 cell nucleus rapidly and induces cell stress response.

    Science.gov (United States)

    Guéguen, Yann; Suhard, David; Poisson, Clémentine; Manens, Line; Elie, Christelle; Landon, Géraldine; Bouvier-Capely, Céline; Rouas, Caroline; Benderitter, Marc; Tessier, Christine

    2015-12-25

    This study aimed to compare the cell stress effects of low and high uranium concentrations and relate them to its localization, precipitate formation, and exposure time. The time-course analysis shows that uranium appears in cell nuclei as a soluble form within 5 min of exposure, and quickly induces expression of antioxidant and DNA repair genes. On the other hand, precipitate formations began at the very beginning of exposure at the 300-μM concentration, but took longer to appear at lower concentrations. Adaptive response might occur at low concentrations but are overwhelmed at high concentrations, especially when uranium precipitates are abundant.

  5. Mercury induces proliferation and reduces cell size in vascular smooth muscle cells through MAPK, oxidative stress and cyclooxygenase-2 pathways

    Energy Technology Data Exchange (ETDEWEB)

    Aguado, Andrea; Galán, María; Zhenyukh, Olha; Wiggers, Giulia A.; Roque, Fernanda R. [Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), 28029, Madrid (Spain); Redondo, Santiago [Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, 28040, Madrid (Spain); Peçanha, Franck [Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), 28029, Madrid (Spain); Martín, Angela [Departamento de Bioquímica, Fisiología y Genética Molecular, Universidad Rey Juan Carlos, 28922, Alcorcón (Spain); Fortuño, Ana [Área de Ciencias Cardiovasculares, Centro de Investigación Médica Aplicada, Universidad de Navarra, 31008, Pamplona (Spain); Cachofeiro, Victoria [Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, 28040, Madrid (Spain); Tejerina, Teresa [Departamento de Farmacología, Facultad de Medicina, Universidad Complutense, 28040, Madrid (Spain); Salaices, Mercedes, E-mail: mercedes.salaices@uam.es [Departamento de Farmacología, Facultad de Medicina, Universidad Autónoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), 28029, Madrid (Spain); and others

    2013-04-15

    Mercury exposure is known to increase cardiovascular risk but the underlying cellular mechanisms remain undetermined. We analyzed whether chronic exposure to HgCl{sub 2} affects vascular structure and the functional properties of vascular smooth muscle cells (VSMC) through oxidative stress/cyclooxygenase-2 dependent pathways. Mesenteric resistance arteries and aortas from Wistar rats treated with HgCl{sub 2} (first dose 4.6 mg kg{sup −1}, subsequent doses 0.07 mg kg{sup −1} day{sup −1}, 30 days) and cultured aortic VSMC stimulated with HgCl{sub 2} (0.05–5 μg/ml) were used. Treatment of rats with HgCl{sub 2} decreased wall thickness of the resistance and conductance vasculature, increased the number of SMC within the media and decreased SMC nucleus size. In VSMCs, exposure to HgCl{sub 2}: 1) induced a proliferative response and a reduction in cell size; 2) increased superoxide anion production, NADPH oxidase activity, gene and/or protein levels of the NADPH oxidase subunit NOX-1, the EC- and Mn-superoxide dismutases and cyclooxygenase-2 (COX-2); 3) induced activation of ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized the proliferative response and the altered cell size induced by HgCl{sub 2}. Blockade of ERK1/2 and p38 signaling pathways abolished the HgCl{sub 2}-induced Nox1 and COX-2 expression and normalized the alterations induced by mercury in cell proliferation and size. In conclusion, long exposure of VSMC to low doses of mercury activates MAPK signaling pathways that result in activation of inflammatory proteins such as NADPH oxidase and COX-2 that in turn induce proliferation of VSMC and changes in cell size. These findings offer further evidence that mercury might be considered an environmental risk factor for cardiovascular disease. - Highlights: ► Chronic HgCl{sub 2} exposure induces vascular remodeling. ► HgCl{sub 2} induces proliferation and decreased cell size in vascular smooth muscle cells. ► HgCl{sub 2} induces

  6. Alterations in cancer cell mechanical properties after fluid shear stress exposure: a micropipette aspiration study

    Directory of Open Access Journals (Sweden)

    Chivukula VK

    2015-01-01

    Full Text Available Venkat Keshav Chivukula,1 Benjamin L Krog,1,2 Jones T Nauseef,2 Michael D Henry,2 Sarah C Vigmostad1 1Department of Biomedical Engineering, 2Department of Molecular Physiology and Biophysics, Holden Comprehensive Cancer Center, University of Iowa, Seamans Center for the Engineering Arts and Sciences, Iowa City, IA, USA Abstract: Over 90% of cancer deaths result not from primary tumor development, but from metastatic tumors that arise after cancer cells circulate to distal sites via the circulatory system. While it is known that metastasis is an inefficient process, the effect of hemodynamic parameters such as fluid shear stress (FSS on the viability and efficacy of metastasis is not well understood. Recent work has shown that select cancer cells may be able to survive and possibly even adapt to FSS in vitro. The current research seeks to characterize the effect of FSS on the mechanical properties of suspended cancer cells in vitro. Nontransformed prostate epithelial cells (PrEC LH and transformed prostate cancer cells (PC-3 were used in this study. The Young's modulus was determined using micropipette aspiration. We examined cells in suspension but not exposed to FSS (unsheared and immediately after exposure to high (6,400 dyn/cm2 and low (510 dyn/cm2 FSS. The PrEC LH cells were ~140% stiffer than the PC-3 cells not exposed to FSS. Post-FSS exposure, there was an increase of ~77% in Young's modulus after exposure to high FSS and a ~47% increase in Young's modulus after exposure to low FSS for the PC-3 cells. There was no significant change in the Young's modulus of PrEC LH cells post-FSS exposure. Our findings indicate that cancer cells adapt to FSS, with an increased Young's modulus being one of the adaptive responses, and that this adaptation is specific only to PC-3 cells and is not seen in PrEC LH cells. Moreover, this adaptation appears to be graded in response to the magnitude of FSS experienced by the cancer cells. This is the first study

  7. A Sensitive Sensor Cell Line for the Detection of Oxidative Stress Responses in Cultured Human Keratinocytes

    Directory of Open Access Journals (Sweden)

    Ute Hofmann

    2014-06-01

    Full Text Available In the progress of allergic and irritant contact dermatitis, chemicals that cause the generation of reactive oxygen species trigger a heat shock response in keratinocytes. In this study, an optical sensor cell line based on cultured human keratinocytes (HaCaT cells expressing green fluorescent protein (GFP under the control of the stress-inducible HSP70B’ promoter were constructed. Exposure of HaCaT sensor cells to 25 µM cadmium, a model substance for oxidative stress induction, provoked a 1.7-fold increase in total glutathione and a ~300-fold induction of transcript level of the gene coding for heat shock protein HSP70B’. An extract of Arnica montana flowers resulted in a strong induction of the HSP70B’ gene and a pronounced decrease of total glutathione in keratinocytes. The HSP70B’ promoter-based sensor cells conveniently detected cadmium-induced stress using GFP fluorescence as read-out with a limit of detection of 6 µM cadmium. In addition the sensor cells responded to exposure of cells to A. montana extract with induction of GFP fluorescence. Thus, the HaCaT sensor cells provide a means for the automated detection of the compromised redox status of keratinocytes as an early indicator of the development of human skin disorders and could be applied for the prediction of skin irritation in more complex in vitro 3D human skin models and in the development of micro-total analysis systems (µTAS that may be utilized in dermatology, toxicology, pharmacology and drug screenings.

  8. Neuroprotective Effect of Carnosine on Primary Culture of Rat Cerebellar Cells under Oxidative Stress.

    Science.gov (United States)

    Lopachev, A V; Lopacheva, O M; Abaimov, D A; Koroleva, O V; Vladychenskaya, E A; Erukhimovich, A A; Fedorova, T N

    2016-05-01

    Dipeptide carnosine (β-alanyl-L-histidine) is a natural antioxidant, but its protective effect under oxidative stress induced by neurotoxins is studied insufficiently. In this work, we show the neuroprotective effect of carnosine in primary cultures of rat cerebellar cells under oxidative stress induced by 1 mM 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), which directly generates free radicals both in the medium and in the cells, and 20 nM rotenone, which increases the amount of intracellular reactive oxygen species (ROS). In both models, adding 2 mM carnosine to the incubation medium decreased cell death calculated using fluorescence microscopy and enhanced cell viability estimated by the MTT assay. The antioxidant effect of carnosine inside cultured cells was demonstrated using the fluorescence probe dichlorofluorescein. Carnosine reduced by half the increase in the number of ROS in neurons induced by 20 nM rotenone. Using iron-induced chemiluminescence, we showed that preincubation of primary neuronal cultures with 2 mM carnosine prevents the decrease in endogenous antioxidant potential of cells induced by 1 mM AAPH and 20 nM rotenone. Using liquid chromatography-mass spectrometry, we showed that a 10-min incubation of neuronal cultures with 2 mM carnosine leads to a 14.5-fold increase in carnosine content in cell lysates. Thus, carnosine is able to penetrate neurons and exerts an antioxidant effect. Western blot analysis revealed the presence of the peptide transporter PEPT2 in rat cerebellar cells, which suggests the possibility of carnosine transport into the cells. At the same time, Western blot analysis showed no carnosine-induced changes in the level of apoptosis regulating proteins of the Bcl-2 family and in the phosphorylation of MAP kinases, which suggests that carnosine could have minimal or no side effects on proliferation and apoptosis control systems in normal cells. PMID:27297901

  9. Geometric guidance of integrin mediated traction stress during stem cell differentiation.

    Science.gov (United States)

    Lee, Junmin; Abdeen, Amr A; Tang, Xin; Saif, Taher A; Kilian, Kristopher A

    2015-11-01

    Cells sense and transduce the chemical and mechanical properties of their microenvironment through cell surface integrin receptors. Traction stress exerted by cells on the extracellular matrix mediates focal adhesion stabilization and regulation of the cytoskeleton for directing biological activity. Understanding how stem cells integrate biomaterials properties through focal adhesions during differentiation is important for the design of soft materials for regenerative medicine. In this paper we use micropatterned hydrogels containing fluorescent beads to explore force transmission through integrins from single mesenchymal stem cells (MSCs) during differentiation. When cultured on polyacrylamide gels, MSCs will express markers associated with osteogenesis and myogenesis in a stiffness dependent manner. The shape of single cells and the composition of tethered matrix protein both influence the magnitude of traction stress applied and the resultant differentiation outcome. We show how geometry guides the spatial positioning of focal adhesions to maximize interaction with the matrix, and uncover a relationship between αvβ3, α5β1 and mechanochemical regulation of osteogenesis. PMID:26285084

  10. Urate Oxidase Knockdown Decreases Oxidative Stress in a Murine Hepatic Cell Line

    Directory of Open Access Journals (Sweden)

    Beth M. Cleveland

    2009-01-01

    Full Text Available Humans, birds, and some primates do not express the uric acid degrading enzyme urate oxidase (UOX and, as a result, have plasma uric acid concentrations higher than UOX expressing animals. Although high uric acid concentrations are suggested to increase the antioxidant defense system and provide a health advantage to animals without UOX, knockout mice lacking UOX develop pathological complications including gout and kidney failure. As an alternative to the knockout model, RNA interference was used to decrease UOX expression using stable transfection in a mouse hepatic cell line (ATCC, FL83B. Urate oxidase mRNA was reduced 66% (p < 0.05 compared to wild type, as measured by real time RT-PCR. To determine if UOX knockdown resulted in enhanced protection against oxidative stress, cells were challenged with hexavalent chromium (Cr(VI or 3-morpholinosydnonimine hydrochloride (SIN-1. Compared to wild type, cells with UOX knockdown exhibited a 37.2 ± 3.5% reduction (p < 0.05 in the electron spin resonance (ESR signal after being exposed to Cr(VI and displayed less DNA fragmentation (p < 0.05 following SIN-1 treatment. Cell viability decreased in wild type cells (p < 0.05, but not cells with UOX knockdown, after treatment with SIN-1. These results are consistent with an increased intracellular uric acid concentration and an increased defense against oxidative stress.

  11. Apoptosis and telomeres shortening related to HIV-1 induced oxidative stress in an astrocytoma cell line

    Directory of Open Access Journals (Sweden)

    Mollace Vincenzo

    2009-05-01

    Full Text Available Abstract Background Oxidative stress plays a key role in the neuropathogenesis of Human Immunodeficiency Virus-1 (HIV-1 infection causing apoptosis of astroglia cells and neurons. Recent data have shown that oxidative stress is also responsible for the acceleration of human fibroblast telomere shortening in vitro. In the present study we analyzed the potential relations occurring between free radicals formation and telomere length during HIV-1 mediated astroglial death. Results To this end, U373 human astrocytoma cells have been directly exposed to X4-using HIV-1IIIB strain, for 1, 3 or 5 days and treated (where requested with N-acetylcysteine (NAC, a cysteine donor involved in the synthesis of glutathione (GSH, a cellular antioxidant and apoptosis has been evaluated by FACS analysis. Quantitative-FISH (Q-FISH has been employed for studying the telomere length while intracellular reduced/oxidized glutathione (GSH/GSSG ratio has been determined by High-Performance Liquid Chromatography (HPLC. Incubation of U373 with HIV-1IIIB led to significant induction of cellular apoptosis that was reduced in the presence of 1 mM NAC. Moreover, NAC improved the GSH/GSSG, a sensitive indicator of oxidative stress, that significantly decreased after HIV-1IIIB exposure in U373. Analysis of telomere length in HIV-1 exposed U373 showed a statistically significant telomere shortening, that was completely reverted in NAC-treated U373. Conclusion Our results support the role of HIV-1-mediated oxidative stress in astrocytic death and the importance of antioxidant compounds in preventing these cellular damages. Moreover, these data indicate that the telomere structure, target for oxidative damage, could be the key sensor of cell apoptosis induced by oxidative stress after HIV infection.

  12. Effects of Cigarette Smoke Condensate on Oxidative Stress, Apoptotic Cell Death, and HIV Replication in Human Monocytic Cells.

    Directory of Open Access Journals (Sweden)

    Pss Rao

    Full Text Available While cigarette smoking is prevalent amongst HIV-infected patients, the effects of cigarette smoke constituents in cells of myeloid lineage are poorly known. Recently, we have shown that nicotine induces oxidative stress through cytochrome P450 (CYP 2A6-mediated pathway in U937 monocytic cells. The present study was designed to examine the effect of cigarette smoke condensate (CSC, which contains majority of tobacco constituents, on oxidative stress, cytotoxicity, expression of CYP1A1, and/or HIV-1 replication in HIV-infected (U1 and uninfected U937 cells. The effects of CSC on induction of CYP1 enzymes in HIV-infected primary macrophages were also analyzed. The results showed that the CSC-mediated increase in production of reactive oxygen species (ROS in U937 cells is dose- and time-dependent. Moreover, CSC treatment was found to induce cytotoxicity in U937 cells through the apoptotic pathway via activation of caspase-3. Importantly, pretreatment with vitamin C blocked the CSC-mediated production of ROS and induction of caspase-3 activity. In U1 cells, acute treatment of CSC increased ROS production at 6H (>2-fold and both ROS (>2 fold and HIV-1 replication (>3-fold after chronic treatment. The CSC mediated effects were associated with robust induction in the expression of CYP1A1 mRNA upon acute CSC treatment of U937 and U1 cells (>20-fold, and upon chronic CSC treatment to U1 cells (>30-fold. In addition, the CYP1A1 induction in U937 cells was mediated through the aromatic hydrocarbon receptor pathway. Lastly, CSC, which is known to increase viral replication in primary macrophages, was also found to induce CYP1 enzymes in HIV-infected primary macrophages. While mRNA levels of both CYP1A1 and CYP1B1 were elevated following CSC treatment, only CYP1B1 protein levels were increased in HIV-infected primary macrophages. In conclusion, these results suggest a possible association between oxidative stress, CYP1 expression, and viral replication in

  13. Fusaric acid induces mitochondrial stress in human hepatocellular carcinoma (HepG2) cells.

    Science.gov (United States)

    Sheik Abdul, Naeem; Nagiah, Savania; Chuturgoon, Anil A

    2016-09-01

    Fusarium spp are common contaminants of maize and produce many mycotoxins, including the fusariotoxin fusaric acid (FA). FA is a niacin related compound, chelator of divalent cations, and mediates toxicity via oxidative stress and possible mitochondrial dysregulation. Sirtuin 3 (SIRT3) is a stress response deacetylase that maintains proper mitochondrial function. We investigated the effect of FA on SIRT3 and oxidative and mitochondrial stress pathways in the hepatocellular carcinoma (HepG2) cell line. We determined FA toxicity (24 h incubation; IC50 = 104 μg/ml) on mitochondrial output, cellular and mitochondrial stress responses, mitochondrial biogenesis and markers of cell death using spectrophotometry, luminometry, qPCR and western blots. FA caused a dose dependent decrease in metabolic activity along with significant depletion of intracellular ATP. FA induced a significant increase in lipid peroxidation, despite up-regulation of the antioxidant transcription factor, Nrf2. FA significantly decreased expression of SIRT3 mRNA with a concomitant decrease in protein expression. Lon protease was also significantly down-regulated. FA induced aberrant mitochondrial biogenesis as evidenced by significantly decreased protein expressions of: PGC-1α, p-CREB, NRF1 and HSP70. Finally, FA activated apoptosis as noted by the significantly increased activity of caspases 3/7 and also induced cellular necrosis. This study provides insight into the molecular mechanisms of FA (a neglected mycotoxin) induced hepatotoxicity. PMID:27390038

  14. Elevated copper and oxidative stress in cancer cells as a target for cancer treatment.

    Science.gov (United States)

    Gupte, Anshul; Mumper, Russell J

    2009-02-01

    As we gain a better understanding of the factors affecting cancer etiology, we can design improved treatment strategies. Over the past three to four decades, there have been numerous successful efforts in recognizing important cellular proteins essential in cancer growth and therefore these proteins have been targeted for cancer treatment. However, studies have shown that targeting one or two proteins in the complex cancer cascade may not be sufficient in controlling and/or inhibiting cancer growth. Therefore, there is a need to examine features which are potentially involved in multiple facets of cancer development. In this review we discuss the targeting of the elevated copper (both in serum and tumor) and oxidative stress levels in cancer with the aid of a copper chelator d-penicillamine (d-pen) for potential cancer treatment. Numerous studies in the literature have reported that both the serum and tumor copper levels are elevated in a variety of malignancies, including both solid tumor and blood cancer. Further, the elevated copper levels have been shown to be directly correlated to cancer progression. Enhanced levels of intrinsic oxidative stress has been shown in variety of tumors, possibly due to the combination of factors such as elevated active metabolism, mitochondrial mutation, cytokines, and inflammation. The cancer cells under sustained ROS stress tend to heavily utilize adaptation mechanisms and may exhaust cellular ROS-buffering capacity. Therefore, the elevated copper levels and increased oxidative stress in cancer cells provide for a prospect of selective cancer treatment.

  15. Protective effect of alpha-mangostin against oxidative stress induced-retinal cell death

    Science.gov (United States)

    Fang, Yuan; Su, Tu; Qiu, Xiaorong; Mao, Pingan; Xu, Yidan; Hu, Zizhong; Zhang, Yi; Zheng, Xinhua; Xie, Ping; Liu, Qinghuai

    2016-01-01

    It is known that oxidative stress plays a pivotal role in age-related macular degeneration (AMD) pathogenesis. Alpha-mangostin is the main xanthone purified from mangosteen known as anti-oxidative properties. The aim of the study was to test the protective effect of alpha-mangostin against oxidative stress both in retina of light-damaged mice model and in hydrogen peroxide (H2O2)-stressed RPE cells. We observed that alpha-mangostin significantly inhibited light-induced degeneration of photoreceptors and 200 μM H2O2-induced apoptosis of RPE cells. 200 μM H2O2-induced generation of reactive oxygen species (ROS) and light-induced generation of malondialdehyde (MDA) were suppressed by alpha-mangostin. Alpha-mangostin stimulation resulted in an increase of superoxide dismutase (SOD) activity, glutathione peroxidase (GPX) activity and glutathione (GSH) content both in vivo and vitro. Furthermore, the mechanism of retinal protection against oxidative stress by alpha-mangostin involves accumulation and the nuclear translocation of the NF-E2-related factor (Nrf2) along with up-regulation the expression of heme oxygenas-1 (HO-1). Meanwhile, alpha-mangostin can activate the expression of PKC-δ and down-regulate the expression of mitogen-activated protein kinases (MAPKs), including ERK1/2, JNK, P38. The results suggest that alpha-mangostin could be a new approach to suspend the onset and development of AMD. PMID:26888416

  16. Bcl-2 family members inhibit oxidative stress-induced programmed cell death in Saccharomyces cerevisiae.

    Science.gov (United States)

    Chen, Shao-Rong; Dunigan, David D; Dickman, Martin B

    2003-05-15

    Selected antiapoptotic genes were expressed in baker's yeast (Saccharomyces cerevisiae) to evaluate cytoprotective effects during oxidative stress. When exposed to treatments resulting in the generation of reactive oxygen species (ROS), including H(2)O(2), menadione, or heat shock, wild-type yeast died and exhibited apoptotic-like characteristics, consistent with previous studies. Yeast strains were generated expressing nematode ced-9, human bcl-2, or chicken bcl-xl genes. These transformants tolerated a range of oxidative stresses, did not display features associated with apoptosis, and remained viable under conditions that were lethal to wild-type yeast. Yeast strains expressing a mutant antiapoptotic gene (bcl-2 deltaalpha 5-6), known to be nonfunctional in mammalian cells, were unable to tolerate any of the ROS-generating insults. These data are the first report showing CED-9 has cytoprotective effects against oxidative stress, and add CED-9 to the list of Bcl-2 protein family members that modulate ROS-mediated programmed cell death. In addition, these data indicate that Bcl-2 family members protect wild-type yeast from physiological stresses. Taken together, these data support the concept of the broad evolutionary conservation and functional similarity of the apoptotic processes in eukaryotic organisms.

  17. Pulsatile atheroprone shear stress affects the expression of transient receptor potential channels in human endothelial cells

    DEFF Research Database (Denmark)

    Thilo, Florian; Vorderwülbecke, Bernd J; Marki, Alex;

    2012-01-01

    shear stress, producing a constant laminar flow (generating a shear stress of 6 dyne/cm(2)), laminar pulsatile atheroprotective flow (with a mean shear stress of 20 dyne/cm(2)), or laminar atheroprone bidirectional flow (with a mean shear stress of 0 dyne/cm(2)) differentially induced TRPC6 and TRPV1 m......RNA as measured by quantitative real-time RT-PCR and normalized to GAPDH expression. Thereby, TRPC6 and TRPV1 mRNA expressions were significantly increased after 24 hours of exposure to an atheroprone flow profile compared with an atheroprotective flow profile. Furthermore, the expression of transcription factors...... GATA1 and GATA4 was significantly correlated with the expression of TRPC6 mRNA. In contrast, after 24 hours of constant laminar flow, the expression of TRPC6 and TRPV1 mRNA was unchanged, whereas the expression of TRPC3 and TRPM7 was significantly higher in endothelial cells exposed to shear stress...

  18. Residual stresses and strength of multilayer tape cast solid oxide fuel and electrolysis half-cells

    DEFF Research Database (Denmark)

    Charlas, Benoit; Frandsen, Henrik Lund; Brodersen, Karen;

    2015-01-01

    coefficient (TEC) mismatch between the layers, cumulated from high temperature, induces significant residual stresses in the half-cells. Furthermore, it has been observed that MTC half-cells with 4 layers (MTC4: support, fuel electrode, electrolyte and barrier layer) are sometimes more fragile to handle than...... the electrolyte on the compressive side corresponds to the strength of the support. With the loading in the other direction (electrolyte on the tensile side), the origin of the failure is in a different layer for MTC3 (fuel electrode) and for MTC4 (barrier layer). In order to decrease the tensile...... residual stresses, especially in the outer barrier-layer, possible changes to the layer properties are discussed and some optimization guidelines proposed....

  19. Regulation of SUMO2 Target Proteins by the Proteasome in Human Cells Exposed to Replication Stress

    DEFF Research Database (Denmark)

    Bursomanno, Sara; McGouran, Joanna F; Kessler, Benedikt M;

    2015-01-01

    In human cells, SUMO2 is predominantly conjugated to target proteins in response to cellular stress. Previous studies suggested that proteins conjugated to SUMO2, but not to SUMO1, could be regulated by the ubiquitin-mediated proteasome system. Hence, we set out to understand the role of the prot......In human cells, SUMO2 is predominantly conjugated to target proteins in response to cellular stress. Previous studies suggested that proteins conjugated to SUMO2, but not to SUMO1, could be regulated by the ubiquitin-mediated proteasome system. Hence, we set out to understand the role...... of genome instability, which is suggested to drive tumorigenesis and possibly aging, our data will facilitate future functional studies in the fields of DNA metabolism and cancer biology....

  20. Mitochondria are required for ATM activation by extranuclear oxidative stress in cultured human hepatoblastoma cell line Hep G2 cells

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Akinori, E-mail: morita@tokushima-u.ac.jp [Department of Radiation Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Department of Radiological Science, Institute of Health Biosciences, The University of Tokushima Graduate School, Tokushima 770-8509 (Japan); Tanimoto, Keiji; Murakami, Tomoki; Morinaga, Takeshi [Department of Radiation Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Hosoi, Yoshio, E-mail: hosoi@med.tohoku.ac.jp [Department of Radiation Medicine, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima 734-8553 (Japan); Department of Radiation Biology, Graduate School of Medicine, Tohoku University, Sendai 980-8575 (Japan)

    2014-01-24

    Highlights: • Oxidative ATM activation can occur in the absence of nuclear DNA damage response. • The oxidized Hep G2 cells were subjected to subcellular fractionation. • The obtained results suggest that the ATM activation occurs in mitochondria. • ATM failed to respond to oxidative stress in mitochondria-depleted Hep G2 cells. • Mitochondria are required for the oxidative activation of ATM. - Abstract: Ataxia–telangiectasia mutated (ATM) is a serine/threonine protein kinase that plays a central role in DNA damage response (DDR). A recent study reported that oxidized ATM can be active in the absence of DDR. However, the issue of where ATM is activated by oxidative stress remains unclear. Regarding the localization of ATM, two possible locations, namely, mitochondria and peroxisomes are possible. We report herein that ATM can be activated when exposed to hydrogen peroxide without inducing nuclear DDR in Hep G2 cells, and the oxidized cells could be subjected to subcellular fractionation. The first detergent-based fractionation experiment revealed that active, phosphorylated ATM was located in the second fraction, which also contained both mitochondria and peroxisomes. An alternative fractionation method involving homogenization and differential centrifugation, which permits the light membrane fraction containing peroxisomes to be produced, but not mitochondria, revealed that the light membrane fraction contained only traces of ATM. In contrast, the heavy membrane fraction, which mainly contained mitochondrial components, was enriched in ATM and active ATM, suggesting that the oxidative activation of ATM occurs in mitochondria and not in peroxisomes. In Rho 0-Hep G2 cells, which lack mitochondrial DNA and functional mitochondria, ATM failed to respond to hydrogen peroxide, indicating that mitochondria are required for the oxidative activation of ATM. These findings strongly suggest that ATM can be activated in response to oxidative stress in mitochondria

  1. Mitochondria are required for ATM activation by extranuclear oxidative stress in cultured human hepatoblastoma cell line Hep G2 cells

    International Nuclear Information System (INIS)

    Highlights: • Oxidative ATM activation can occur in the absence of nuclear DNA damage response. • The oxidized Hep G2 cells were subjected to subcellular fractionation. • The obtained results suggest that the ATM activation occurs in mitochondria. • ATM failed to respond to oxidative stress in mitochondria-depleted Hep G2 cells. • Mitochondria are required for the oxidative activation of ATM. - Abstract: Ataxia–telangiectasia mutated (ATM) is a serine/threonine protein kinase that plays a central role in DNA damage response (DDR). A recent study reported that oxidized ATM can be active in the absence of DDR. However, the issue of where ATM is activated by oxidative stress remains unclear. Regarding the localization of ATM, two possible locations, namely, mitochondria and peroxisomes are possible. We report herein that ATM can be activated when exposed to hydrogen peroxide without inducing nuclear DDR in Hep G2 cells, and the oxidized cells could be subjected to subcellular fractionation. The first detergent-based fractionation experiment revealed that active, phosphorylated ATM was located in the second fraction, which also contained both mitochondria and peroxisomes. An alternative fractionation method involving homogenization and differential centrifugation, which permits the light membrane fraction containing peroxisomes to be produced, but not mitochondria, revealed that the light membrane fraction contained only traces of ATM. In contrast, the heavy membrane fraction, which mainly contained mitochondrial components, was enriched in ATM and active ATM, suggesting that the oxidative activation of ATM occurs in mitochondria and not in peroxisomes. In Rho 0-Hep G2 cells, which lack mitochondrial DNA and functional mitochondria, ATM failed to respond to hydrogen peroxide, indicating that mitochondria are required for the oxidative activation of ATM. These findings strongly suggest that ATM can be activated in response to oxidative stress in mitochondria

  2. Hydrogénation catalytique des calix[4]pyrolles pour l'obtention de nouveaux ligands: synthèses, structures, complexes de cuivre et de manganèse et leur application dans des processus d'oxydation catalytique

    OpenAIRE

    Blangy, Valeria; Neier, Reinhard

    2008-01-01

    Le but de ce travail de thèse consistait à développer un nouveau système catalytique à base de manganèse efficace pour le processus d’oxydation avec H2O2 comme oxydant. La première partie de cette thèse concerne les méso-octaalkylporphyrinogènes, les substrats de notre étude. Ces composés sont facilement accessibles par une condensation en milieu acide entre le pyrrole et diverses cétones. Dans la seconde partie de ce projet, nous avons étudié la réaction d’hydrogénation catalytique hétérogèn...

  3. Etude de l'influence du platine sur le comportement en oxydation d'un système barrière thermique comprenant une sous-couche NiCoCrAlYTa

    OpenAIRE

    Vande Put, Aurélie

    2009-01-01

    La résistance à l'écaillage d'un système barrière thermique est fonction de la composition et microstructure des matériaux constituant le système, ainsi que des procédés utilisés pour son élaboration. Cette thèse s'intéresse à l'influence d'une couche de platine déposée à la surface du dépôt NiCoCrAlYTa (sous-couche) sur le comportement en oxydation du système barrière thermique. Une étude approfondie est d'abord menée afin d'identifier les atouts et points faibles en oxydation cyclique d'un ...

  4. Effect of Sub-Lethal Environmental Stresses on the Cell Survival and Antibacterial Susceptibility of Listeria monocytogenes PTCC1297

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    Mohammad Faezi-Ghasemi

    2015-01-01

    Full Text Available Background: Listeria monocytogenes is slowly becoming drug resistant, study on resistance of this pathogen is important to ensure effective treatment of human listeriosis. The aim of this work was evaluating the changes in susceptibility to antibiotics and cell survival of L. monocytogenes PTCC1297 (serotype 4a after exposure to some stresses. Materials and Methods: In this descriptive-analytic study L. monocytogenes PTCC1297 subjected to sub-lethal environmental stresses including ethanol (5% v/v, sodium chloride (7% w/v, acid (HCl, pH=5.0, hydrogen peroxide (600 ppm and heat (45ºC. After the stress treatments, antibacterial susceptibility and cell survival were determined. Results: Exposing to hydrogen peroxide (600 ppm and heat (45ºC significantly (p<0.05 increased resistance to all selective antibiotics. But treating to stresses such as hydrochloric acid (pH=5.0, sodium chloride (7% w/v and ethanol (5% v/v decreased resistance (p<0.05 to antibiotics. L. monocytogenes PTCC1297 cell survival was decreased at 60ºC which is considered as lethal condition. Exposing to sub-lethal acid stress increased survival to high acidic conditions (pH=3.0. But upon increasing hydrogen peroxide the viability of cell decreased. Treating the cells with ethanol (14% v/v and NaCl (20% w/v increased cell survival. Conclusion: Adaptation to some stresses including hydrogen peroxide and heat increase resistance to antibiotics. Stresses such as ethanol, hydrochloric acid and sodium chloride act in adverse. Exposing to some sub-lethal stresses increased cell survival when lethal doses of the same stress such as acid, ethanol and sodium chloride were used. But, when we treating the cells to sublethal doses of H2O2 and heat the cell survival decreased.

  5. Metabolic stress responses in Drosophila are modulated by brain neurosecretory cells that produce multiple neuropeptides.

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    Lily Kahsai

    Full Text Available In Drosophila, neurosecretory cells that release peptide hormones play a prominent role in the regulation of development, growth, metabolism, and reproduction. Several types of peptidergic neurosecretory cells have been identified in the brain of Drosophila with release sites in the corpora cardiaca and anterior aorta. We show here that in adult flies the products of three neuropeptide precursors are colocalized in five pairs of large protocerebral neurosecretory cells in two clusters (designated ipc-1 and ipc-2a: Drosophila tachykinin (DTK, short neuropeptide F (sNPF and ion transport peptide (ITP. These peptides were detected by immunocytochemistry in combination with GFP expression driven by the enhancer trap Gal4 lines c929 and Kurs-6, both of which are expressed in ipc-1 and 2a cells. This mix of colocalized peptides with seemingly unrelated functions is intriguing and prompted us to initiate analysis of the function of the ten neurosecretory cells. We investigated the role of peptide signaling from large ipc-1 and 2a cells in stress responses by monitoring the effect of starvation and desiccation in flies with levels of DTK or sNPF diminished by RNA interference. Using the Gal4-UAS system we targeted the peptide knockdown specifically to ipc-1 and 2a cells with the c929 and Kurs-6 drivers. Flies with reduced DTK or sNPF levels in these cells displayed decreased survival time at desiccation and starvation, as well as increased water loss at desiccation. Our data suggest that homeostasis during metabolic stress requires intact peptide signaling by ipc-1 and 2a neurosecretory cells.

  6. Adaptation of endothelial cells to physiologically-modeled, variable shear stress.

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    Joseph S Uzarski

    Full Text Available Endothelial cell (EC function is mediated by variable hemodynamic shear stress patterns at the vascular wall, where complex shear stress profiles directly correlate with blood flow conditions that vary temporally based on metabolic demand. The interactions of these more complex and variable shear fields with EC have not been represented in hemodynamic flow models. We hypothesized that EC exposed to pulsatile shear stress that changes in magnitude and duration, modeled directly from real-time physiological variations in heart rate, would elicit phenotypic changes as relevant to their critical roles in thrombosis, hemostasis, and inflammation. Here we designed a physiological flow (PF model based on short-term temporal changes in blood flow observed in vivo and compared it to static culture and steady flow (SF at a fixed pulse frequency of 1.3 Hz. Results show significant changes in gene regulation as a function of temporally variable flow, indicating a reduced wound phenotype more representative of quiescence. EC cultured under PF exhibited significantly higher endothelial nitric oxide synthase (eNOS activity (PF: 176.0±11.9 nmol/10(5 EC; SF: 115.0±12.5 nmol/10(5 EC, p = 0.002 and lower TNF-a-induced HL-60 leukocyte adhesion (PF: 37±6 HL-60 cells/mm(2; SF: 111±18 HL-60/mm(2, p = 0.003 than cells cultured under SF which is consistent with a more quiescent anti-inflammatory and anti-thrombotic phenotype. In vitro models have become increasingly adept at mimicking natural physiology and in doing so have clarified the importance of both chemical and physical cues that drive cell function. These data illustrate that the variability in metabolic demand and subsequent changes in perfusion resulting in constantly variable shear stress plays a key role in EC function that has not previously been described.

  7. Relevance of Endoplasmic Reticulum Stress Cell Signaling in Liver Cold Ischemia Reperfusion Injury

    OpenAIRE

    Emma Folch-Puy; Arnau Panisello; Joan Oliva; Alexandre Lopez; Carlos Castro Benítez; René Adam; Joan Roselló-Catafau

    2016-01-01

    International audience The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprise...

  8. Gold Nanoparticles Impinge on Nucleoli and the Stress Response in MCF7 Breast Cancer Cells

    OpenAIRE

    Mohamed Kodiha; Hicham Mahboubi; Dusica Maysinger; Ursula Stochaj

    2016-01-01

    Cancer cells can take up gold nanoparticles of different morphologies. These particles interact with the plasma membrane and often travel to intracellular organelles. Among organelles, the nucleus is especially susceptible to the damage that is inflicted by gold nanoparticles. Located inside the nucleus, nucleoli are specialized compartments that transcribe ribosomal RNA genes, produce ribosomes and function as cellular stress sensors. Nucleoli are partic‐ ularly prone to gold nanoparticle-in...

  9. Microstructure et proprietes electriques de l'oxyde de vanadium pour les microbolometres

    Science.gov (United States)

    Cadieux, Catherine

    section contains V3O7 in addition to the multiple orientations of V2O5. Those germinations which have already been observed but not explained in literature can be attributed to the accumulation of germination centers, a stress buildup for the crystalline sections, and a substrate heating caused by the ions bombardment. This last effect is also suggested to be the cause of the amorphous phase crystallisation for the films with longer deposition times. Films deposited at different temperatures show the same microstructure transitions. Two different behavior regimes can be proposed as function of the adatoms' energy. For low temperature, increasing the adatom energy increases the diffusion which promotes the formation of the lowest surface energy stoichiometry and orientation, V2O 5(001). At higher temperature, energy is sufficient to form more energetically expensive orientation and phases. Resistivity is strongly dependant on grain boundaries density as seen by its relationship with lateral grain size. The thin film resistivity is also increased with the number of different crystallographic orientation present in it. To circumvent the high sheet resistance of the deposited single layer films, a multilayer stacking of alternating oxides and metal layers has been deposited. This approach has permitted this project's industrial collaborator to obtain a sheet resistance of 250 kO/□and a TCR of -1.59 %/K. The microstructure of the multilayer is however very heterogeneous. Not only can the metal layers be identified, it is also possible to observe the amorphous to polycrystalline transition described higher for every oxide layer. This multilayer, as well as the best single layer film produced have been annealed for 2 hours at 400°C in high vacuum. The annealed multilayer doesn't show any diffraction peaks, has very low resistance, and an almost null TCR generally attributed to metallic compounds We suggest that the diffusion of the vanadium layers into the stack created a

  10. Astaxanthin from Haematococcus pluvialis Prevents Oxidative Stress on Human Endothelial Cells without Toxicity

    Science.gov (United States)

    Régnier, Philippe; Bastias, Jorge; Rodriguez-Ruiz, Violeta; Caballero-Casero, Noelia; Caballo, Carmen; Sicilia, Dolores; Fuentes, Axelle; Maire, Murielle; Crepin, Michel; Letourneur, Didier; Gueguen, Virginie; Rubio, Soledad; Pavon-Djavid, Graciela

    2015-01-01

    Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of synthetic astaxanthin. Natural extracts were obtained either by solvent or supercritical extraction methods. UV, HPLC-DAD and (HPLC-(atmospheric pressure chemical ionization (APCI)+)/ion trap-MS) characterizations of both natural extracts showed similar compositions of carotenoids, but different percentages in free astaxanthin and its ester derivatives. The Trolox equivalent antioxidant capacity (TEAC) assay showed that natural extracts containing esters displayed stronger antioxidant activities than free astaxanthin. Their antioxidant capacities to inhibit intracellular oxidative stress were then evaluated on HUVEC cells. The intracellular antioxidant activity in natural extracts was approximately 90-times higher than synthetic astaxanthin (5 µM). No modification, neither in the morphology nor in the viability, of vascular human cells was observed by in vitro biocompatibility study up to 10 µM astaxanthin concentrations. Therefore, these results revealed the therapeutic potential of the natural extracts in vascular human cell protection against oxidative stress without toxicity, which could be exploited in prevention and/or treatment of cardiovascular diseases. PMID:25962124

  11. Astaxanthin from Haematococcus pluvialis Prevents Oxidative Stress on Human Endothelial Cells without Toxicity

    Directory of Open Access Journals (Sweden)

    Philippe Régnier

    2015-05-01

    Full Text Available Astaxanthin, a powerful antioxidant, is a good candidate for the prevention of intracellular oxidative stress. The aim of the study was to compare the antioxidant activity of astaxanthin present in two natural extracts from Haematococcus pluvialis, a microalgae strain, with that of synthetic astaxanthin. Natural extracts were obtained either by solvent or supercritical extraction methods. UV, HPLC-DAD and (HPLC-(atmospheric pressure chemical ionization (APCI+/ion trap-MS characterizations of both natural extracts showed similar compositions of carotenoids, but different percentages in free astaxanthin and its ester derivatives. The Trolox equivalent antioxidant capacity (TEAC assay showed that natural extracts containing esters displayed stronger antioxidant activities than free astaxanthin. Their antioxidant capacities to inhibit intracellular oxidative stress were then evaluated on HUVEC cells. The intracellular antioxidant activity in natural extracts was approximately 90-times higher than synthetic astaxanthin (5 µM. No modification, neither in the morphology nor in the viability, of vascular human cells was observed by in vitro biocompatibility study up to 10 µM astaxanthin concentrations. Therefore, these results revealed the therapeutic potential of the natural extracts in vascular human cell protection against oxidative stress without toxicity, which could be exploited in prevention and/or treatment of cardiovascular diseases.

  12. Chlorobenzene induces oxidative stress in human lung epithelial cells in vitro

    International Nuclear Information System (INIS)

    Chlorobenzene is a volatile organic compound (VOC) that is widely used as a solvent, degreasing agent and chemical intermediate in many industrial settings. Occupational studies have shown that acute and chronic exposure to chlorobenzene can cause irritation of the mucosa of the upper respiratory tract and eyes. Using in vitro assays, we have shown in a previous study that human bronchial epithelial cells release inflammatory mediators such as the cytokine monocyte chemoattractant protein-1 (MCP-1) in response to chlorobenzene. This response is mediated through the NF-κB signaling pathway. Here, we investigated the effects of monochlorobenzene on human lung cells, with emphasis on potential alterations of the redox equilibrium to clarify whether the chlorobenzene-induced inflammatory response in lung epithelial cells is caused via an oxidative stress-dependent mechanism. We found that expression of cellular markers for oxidative stress, such as heme oxygenase 1 (HO-1), glutathione S-transferase π1 (GSTP1), superoxide dismutase 1 (SOD1), prostaglandin-endoperoxide synthase 2 (PTGS2) and dual specificity phosphatase 1 (DUSP1), were elevated in the presence of monochlorobenzene. Likewise, intracellular reactive oxygen species (ROS) were increased in response to exposure. However, in the presence of the antioxidants N-(2-mercaptopropionyl)-glycine (MPG) or bucillamine, chlorobenzene-induced upregulation of marker proteins and release of the inflammatory mediator MCP-1 are suppressed. These results complement our previous findings and point to an oxidative stress-mediated inflammatory response following chlorobenzene exposure.

  13. Cell Wall Amine Oxidases: New Players in Root Xylem Differentiation under Stress Conditions

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    Sandip A. Ghuge

    2015-07-01

    Full Text Available Polyamines (PAs are aliphatic polycations present in all living organisms. A growing body of evidence reveals their involvement as regulators in a variety of physiological and pathological events. They are oxidatively deaminated by amine oxidases (AOs, including copper amine oxidases (CuAOs and flavin adenine dinucleotide (FAD-dependent polyamine oxidases (PAOs. The biologically-active hydrogen peroxide (H2O2 is a shared compound in all of the AO-catalyzed reactions, and it has been reported to play important roles in PA-mediated developmental and stress-induced processes. In particular, the AO-driven H2O2 biosynthesis in the cell wall is well known to be involved in plant wound healing and pathogen attack responses by both triggering peroxidase-mediated wall-stiffening events and signaling modulation of defense gene expression. Extensive investigation by a variety of methodological approaches revealed high levels of expression of cell wall-localized AOs in root xylem tissues and vascular parenchyma of different plant species. Here, the recent progresses in understanding the role of cell wall-localized AOs as mediators of root xylem differentiation during development and/or under stress conditions are reviewed. A number of experimental pieces of evidence supports the involvement of apoplastic H2O2 derived from PA oxidation in xylem tissue maturation under stress-simulated conditions.

  14. The influence of hydroxyurea on oxidative stress in sickle cell anemia

    Science.gov (United States)

    Torres, Lidiane de Souza; da Silva, Danilo Grünig Humberto; Belini Junior, Edis; de Almeida, Eduardo Alves; Lobo, Clarisse Lopes de Castro; Cançado, Rodolfo Delfini; Ruiz, Milton Artur; Bonini-Domingos, Claudia Regina

    2012-01-01

    Objective The oxidative stress in 20 sickle cell anemia patients taking hydroxyurea and 13 sickle cell anemia patients who did not take hydroxyurea was compared with a control group of 96 individuals without any hemoglobinopathy. Methods Oxidative stress was assessed by thiobarbituric acid reactive species production, the Trolox-equivalent antioxidant capacity and plasma glutathione levels. Results Thiobarbituric acid reactive species values were higher in patients without specific medication, followed by patients taking hydroxyurea and the Control Group (p < 0.0001). The antioxidant capacity was higher in patients taking hydroxyurea and lower in the Control Group (p = 0.0002 for Trolox-equivalent antioxidant capacity and p < 0.0292 for plasma glutathione). Thiobarbituric acid reactive species levels were correlated with higher hemoglobin S levels (r = 0.55; p = 0.0040) and lower hemoglobin F concentrations(r = -0.52; p = 0.0067). On the other hand, plasma glutathione levels were negatively correlated with hemoglobin S levels (r = -0.49; p = 0.0111) and positively associated with hemoglobin F values (r = 0.56; p = 0.0031). Conclusion Sickle cell anemia patients have high oxidative stress and, conversely, increased antioxidant activity. The increase in hemoglobin F levels provided by hydroxyurea and its antioxidant action may explain the reduction in lipid peroxidation and increased antioxidant defenses in these individuals. PMID:23323065

  15. The influence of hydroxyurea on oxidative stress in sickle cell anemia

    Directory of Open Access Journals (Sweden)

    Lidiane de Souza Torres

    2012-01-01

    Full Text Available OBJECTIVE: The oxidative stress in 20 sickle cell anemia patients taking hydroxyurea and 13 sickle cell anemia patients who did not take hydroxyurea was compared with a control group of 96 individuals without any hemoglobinopathy. METHODS: Oxidative stress was assessed by thiobarbituric acid reactive species production, the Trolox-equivalent antioxidant capacity and plasma glutathione levels. RESULTS: Thiobarbituric acid reactive species values were higher in patients without specific medication, followed by patients taking hydroxyurea and the Control Group (p < 0.0001. The antioxidant capacity was higher in patients taking hydroxyurea and lower in the Control Group (p = 0.0002 for Trolox-equivalent antioxidant capacity and p < 0.0292 for plasma glutathione. Thiobarbituric acid reactive species levels were correlated with higher hemoglobin S levels (r = 0.55; p = 0.0040 and lower hemoglobin F concentrations(r = -0.52; p = 0.0067. On the other hand, plasma glutathione levels were negatively correlated with hemoglobin S levels (r = -0.49; p = 0.0111 and positively associated with hemoglobin F values (r = 0.56; p = 0.0031. CONCLUSION: Sickle cell anemia patients have high oxidative stress and, conversely, increased antioxidant activity. The increase in hemoglobin F levels provided by hydroxyurea and its antioxidant action may explain the reduction in lipid peroxidation and increased antioxidant defenses in these individuals.

  16. Nuclear Factor-κB Modulates Cellular Glutathione and Prevents Oxidative Stress in Cancer Cells

    OpenAIRE

    Meng, Qinghang; Peng, Zhimin; CHEN Liang; Si, Jutong; Dong, Zhongyun; Xia, Ying

    2010-01-01

    The NF-κB is best known for its role in inflammation. Here we show that constitutive NF-κB activity in cancer cells promotes the biosynthesis of redox scavenger glutathione (GSH), which in turn confers resistance to oxidative stress. Inhibition of NF-κB significantly decreases GSH in several lines of human leukemia and prostate cancer cells possessing high or moderate NF-κB activities. Concomitantly, NF-κB inhibition by pharmacological and molecular means sensitizes “NF-κB positive” cancer ce...

  17. Connexin 43 Channels Protect Osteocytes against Oxidative Stress-Induced Cell Death

    OpenAIRE

    Kar, Rekha; Riquelme, Manuel A.; Werner, Sherry; Jiang, Jean X.

    2013-01-01

    The increased osteocyte death by oxidative stress (OS) during aging is a major cause contributing to the impairment of bone quality and bone loss. However, the underlying molecular mechanism is largely unknown. Here, we showed that H2O2 induced cell death of primary osteocytes and osteocytic MLO-Y4 cells, and also caused dose-dependent decrease expression of gap junction and hemichannel-forming connexin 43 (Cx43). The decrease of Cx43 expression was also demonstrated with the treatment of oth...

  18. Modification of cell volume and proliferative capacity of Pseudokirchneriella subcapitata cells exposed to metal stress

    International Nuclear Information System (INIS)

    Highlights: •Metals induce morphological alterations on P. subcapitata. •Algal cell cycle consists: mother cell growth; cell division, with two nucleus divisions; release of four autospores. •Cu(II) and Cr(VI) arrest cell growth before the first nuclear division. •Cd(II) arrests cell growth after the second nuclear division but before the cytokinesis. •The approach used can be useful in the elucidation of different modes of action of pollutants. -- Abstract: The impact of metals (Cd, Cr, Cu and Zn) on growth, cell volume and cell division of the freshwater alga Pseudokirchneriella subcapitata exposed over a period of 72 h was investigated. The algal cells were exposed to three nominal concentrations of each metal: low (closed to 72 h-EC10 values), intermediate (closed to 72 h-EC50 values) and high (upper than 72 h-EC90 values). The exposure to low metal concentrations resulted in a decrease of cell volume. On the contrary, for the highest metal concentrations an increase of cell volume was observed; this effect was particularly notorious for Cd and less pronounced for Zn. Two behaviours were found when algal cells were exposed to intermediate concentrations of metals: Cu(II) and Cr(VI) induced a reduction of cell volume, while Cd(II) and Zn(II) provoked an opposite effect. The simultaneous nucleus staining and cell image analysis, allowed distinguishing three phases in P. subcapitata cell cycle: growth of mother cell; cell division, which includes two divisions of the nucleus; and, release of four autospores. The exposure of P. subcapitata cells to the highest metal concentrations resulted in the arrest of cell growth before the first nucleus division [for Cr(VI) and Cu(II)] or after the second nucleus division but before the cytokinesis (release of autospores) when exposed to Cd(II). The different impact of metals on algal cell volume and cell-cycle progression, suggests that different toxicity mechanisms underlie the action of different metals studied

  19. Modification of cell volume and proliferative capacity of Pseudokirchneriella subcapitata cells exposed to metal stress

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Manuela D. [Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Soares, Eduardo V., E-mail: evs@isep.ipp.pt [Bioengineering Laboratory-CIETI, Chemical Engineering Department, ISEP-School of Engineering of Polytechnic Institute of Porto, Rua Dr António Bernardino de Almeida, 431, 4200-072 Porto (Portugal); IBB-Institute for Biotechnology and Bioengineering, Centre for Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2014-02-15

    Highlights: •Metals induce morphological alterations on P. subcapitata. •Algal cell cycle consists: mother cell growth; cell division, with two nucleus divisions; release of four autospores. •Cu(II) and Cr(VI) arrest cell growth before the first nuclear division. •Cd(II) arrests cell growth after the second nuclear division but before the cytokinesis. •The approach used can be useful in the elucidation of different modes of action of pollutants. -- Abstract: The impact of metals (Cd, Cr, Cu and Zn) on growth, cell volume and cell division of the freshwater alga Pseudokirchneriella subcapitata exposed over a period of 72 h was investigated. The algal cells were exposed to three nominal concentrations of each metal: low (closed to 72 h-EC{sub 10} values), intermediate (closed to 72 h-EC{sub 50} values) and high (upper than 72 h-EC{sub 90} values). The exposure to low metal concentrations resulted in a decrease of cell volume. On the contrary, for the highest metal concentrations an increase of cell volume was observed; this effect was particularly notorious for Cd and less pronounced for Zn. Two behaviours were found when algal cells were exposed to intermediate concentrations of metals: Cu(II) and Cr(VI) induced a reduction of cell volume, while Cd(II) and Zn(II) provoked an opposite effect. The simultaneous nucleus staining and cell image analysis, allowed distinguishing three phases in P. subcapitata cell cycle: growth of mother cell; cell division, which includes two divisions of the nucleus; and, release of four autospores. The exposure of P. subcapitata cells to the highest metal concentrations resulted in the arrest of cell growth before the first nucleus division [for Cr(VI) and Cu(II)] or after the second nucleus division but before the cytokinesis (release of autospores) when exposed to Cd(II). The different impact of metals on algal cell volume and cell-cycle progression, suggests that different toxicity mechanisms underlie the action of

  20. Safety of Desmodium adscendens extract on hepatocytes and renal cells. Protective effect against oxidative stress.

    Directory of Open Access Journals (Sweden)

    C. Francois

    2015-03-01

    RESULTS: A viability test (MTS, a cytotoxicity assay (LDH release and a study of the cell morphology revealed that pretreatment with 1 mg/ml or 10 mg/ml DA did not alter viability or LDH release in HEPG2 or LLCPK1 cells. However, DA at the dose of 100 mg/ml significantly decreased cell viability, by about 40% (P <0.05. Further, MTS studies revealed that DA 1 mg/ml or 10 mg/ml protected LLC-PK1 cells against a glucose-induced oxidative stress of 24 hours (P<0.05. CONCLUSION: Hence, the lowest concentrations of DA (1mg/ml and 10mg/ml were safe for HEPG2 and LLCPK1 and protective against an oxidative stress in LLC-PK1 cells. These data suggest that DA extracts used as a traditional herbal as food health supplements should be used at the lowest dosage. [J Intercult Ethnopharmacol 2015; 4(1.000: 1-5

  1. Oncogenic Herpesvirus Utilizes Stress-Induced Cell Cycle Checkpoints for Efficient Lytic Replication.

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    Giuseppe Balistreri

    2016-02-01

    Full Text Available Kaposi's sarcoma herpesvirus (KSHV causes Kaposi's sarcoma and certain lymphoproliferative malignancies. Latent infection is established in the majority of tumor cells, whereas lytic replication is reactivated in a small fraction of cells, which is important for both virus spread and disease progression. A siRNA screen for novel regulators of KSHV reactivation identified the E3 ubiquitin ligase MDM2 as a negative regulator of viral reactivation. Depletion of MDM2, a repressor of p53, favored efficient activation of the viral lytic transcription program and viral reactivation. During lytic replication cells activated a p53 response, accumulated DNA damage and arrested at G2-phase. Depletion of p21, a p53 target gene, restored cell cycle progression and thereby impaired the virus reactivation cascade delaying the onset of virus replication induced cytopathic effect. Herpesviruses are known to reactivate in response to different kinds of stress, and our study now highlights the molecular events in the stressed host cell that KSHV has evolved to utilize to ensure efficient viral lytic replication.

  2. Oncogenic Herpesvirus Utilizes Stress-Induced Cell Cycle Checkpoints for Efficient Lytic Replication.

    Science.gov (United States)

    Balistreri, Giuseppe; Viiliäinen, Johanna; Turunen, Mikko; Diaz, Raquel; Lyly, Lauri; Pekkonen, Pirita; Rantala, Juha; Ojala, Krista; Sarek, Grzegorz; Teesalu, Mari; Denisova, Oxana; Peltonen, Karita; Julkunen, Ilkka; Varjosalo, Markku; Kainov, Denis; Kallioniemi, Olli; Laiho, Marikki; Taipale, Jussi; Hautaniemi, Sampsa; Ojala, Päivi M

    2016-02-01

    Kaposi's sarcoma herpesvirus (KSHV) causes Kaposi's sarcoma and certain lymphoproliferative malignancies. Latent infection is established in the majority of tumor cells, whereas lytic replication is reactivated in a small fraction of cells, which is important for both virus spread and disease progression. A siRNA screen for novel regulators of KSHV reactivation identified the E3 ubiquitin ligase MDM2 as a negative regulator of viral reactivation. Depletion of MDM2, a repressor of p53, favored efficient activation of the viral lytic transcription program and viral reactivation. During lytic replication cells activated a p53 response, accumulated DNA damage and arrested at G2-phase. Depletion of p21, a p53 target gene, restored cell cycle progression and thereby impaired the virus reactivation cascade delaying the onset of virus replication induced cytopathic effect. Herpesviruses are known to reactivate in response to different kinds of stress, and our study now highlights the molecular events in the stressed host cell that KSHV has evolved to utilize to ensure efficient viral lytic replication.

  3. Protective mechanism of agmatine pretreatment on RGC-5 cells injured by oxidative stress

    Directory of Open Access Journals (Sweden)

    Y. Iizuka

    2010-04-01

    Full Text Available Agmatine has neuroprotective effects on retinal ganglion cells (RGCs as well as cortical and spinal neurons. It protects RGCs from oxidative stress even when it is not present at the time of injury. As agmatine has high affinity for various cellular receptors, we assessed protective mechanisms of agmatine using transformed RGCs (RGC-5 cell line. Differentiated RGC-5 cells were pretreated with 100 μM agmatine and consecutively exposed to 1.0 mM hydrogen peroxide (H2O2. Cell viability was determined by measuring lactate dehydrogenase (LDH, and the effects of selective alpha 2-adrenergic receptor antagonist yohimbine (0-500 nM and N-methyl-D-aspartic acid (NMDA receptor agonist NMDA (0-100 µM were evaluated. Agmatine’s protective effect was compared to a selective NMDA receptor antagonist MK-801. After a 16-h exposure to H2O2, the LDH assay showed cell loss greater than 50%, which was reduced to about 30% when agmatine was pretreated before injury. Yohimbine almost completely inhibited agmatine’s protective effect, but NMDA did not. In addition, MK-801 (0-100 µM did not significantly attenuate the H2O2-induced cytotoxicity. Our results suggest that neuroprotective effects of agmatine on RGCs under oxidative stress may be mainly attributed to the alpha 2-adrenergic receptor signaling pathway.

  4. Relevance of Endoplasmic Reticulum Stress Cell Signaling in Liver Cold Ischemia Reperfusion Injury.

    Science.gov (United States)

    Folch-Puy, Emma; Panisello, Arnau; Oliva, Joan; Lopez, Alexandre; Castro Benítez, Carlos; Adam, René; Roselló-Catafau, Joan

    2016-01-01

    The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI) of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes. PMID:27231901

  5. Relevance of Endoplasmic Reticulum Stress Cell Signaling in Liver Cold Ischemia Reperfusion Injury

    Directory of Open Access Journals (Sweden)

    Emma Folch-Puy

    2016-05-01

    Full Text Available The endoplasmic reticulum (ER is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS. This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusion injury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR, which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusion injury (IRI of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes.

  6. Enhanced stress resistance of Deinococcus radiodurans cells in the dried state

    Science.gov (United States)

    Bauermeister, Anja; Moeller, Ralf; Reitz, Guenther; Billi, Daniela; Rettberg, Petra

    Liquid water is often regarded as a pre-requisite for life as we know it. However, some organisms can survive prolonged periods in a desiccated state and seem to resist other environmental stres-sors even better when water is absent. We tested this observation in Deinococcus radiodurans, a non-sporeforming soil bacterium well-known for its outstanding resistance to DNA damaging stressors, including high doses of UV and ionizing radiation, oxidants, and desiccation. Due to its polyextremophilic characteristics it has been regarded as a model organism in astrobiological research. To determine if the cellular changes imposed by the removal of water have an effect on the stress resistance of D. radiodurans, we compared the survival capacity of dried cells with that of hydrated cells after exposure to mono-and polychromatic UV radiation, -radiation, and heat shock (85C). In all cases, resistance was enhanced in dried cells. It is suggested that these effects are mainly due to a reduced oxidative stress in dried cells, as the metabolism is shut down and radical diffusion is very limited. Hence, desiccating conditions as encountered in space vacuum or on arid planets such as Mars may be beneficial instead of detrimental to the survival of some polyextremophilic microbes. Ongoing experiments aim to evaluate damage at a subcellular level in dried and hydrated cells after exposure to irradiation or heat shock.

  7. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Science.gov (United States)

    Li, Gongbo; Petiwala, Sakina M; Pierce, Dana R; Nonn, Larisa; Johnson, Jeremy J

    2013-01-01

    The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER) machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE) was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs) procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  8. Selective modulation of endoplasmic reticulum stress markers in prostate cancer cells by a standardized mangosteen fruit extract.

    Directory of Open Access Journals (Sweden)

    Gongbo Li

    Full Text Available The increased proliferation of cancer cells is directly dependent on the increased activity of the endoplasmic reticulum (ER machinery which is responsible for protein folding, assembly, and transport. In fact, it is so critical that perturbations in the endoplasmic reticulum can lead to apoptosis. This carefully regulated organelle represents a unique target of cancer cells while sparing healthy cells. In this study, a standardized mangosteen fruit extract (MFE was evaluated for modulating ER stress proteins in prostate cancer. Two human prostate cancer cell lines, 22Rv1 and LNCaP, and prostate epithelial cells (PrECs procured from two patients undergoing radical prostatectomy were treated with MFE. Flow cytometry, MTT, BrdU and Western blot were used to evaluate cell apoptosis, viability, proliferation and ER stress. Next, we evaluated MFE for microsomal stability and anti-cancer activity in nude mice. MFE induced apoptosis, decreased viability and proliferation in prostate cancer cells. MFE increased the expression of ER stress proteins. Interestingly, MFE selectively promotes ER stress in prostate cancer cells while sparing PrECs. MFE suppressed tumor growth in a xenograft tumor model without obvious toxicity. Mangosteen fruit extract selectively promotes endoplasmic reticulum stress in cancer cells while sparing non-tumorigenic prostate epithelial cells. Furthermore, in an in vivo setting mangosteen fruit extract significantly reduces xenograft tumor formation.

  9. Revealing stiffening and brittling of chronic myelogenous leukemia hematopoietic primary cells through their temporal response to shear stress

    Science.gov (United States)

    Laperrousaz, B.; Berguiga, L.; Nicolini, F. E.; Martinez-Torres, C.; Arneodo, A.; Maguer Satta, V.; Argoul, F.

    2016-06-01

    Cancer cell transformation is often accompanied by a modification of their viscoelastic properties. When capturing the stress-to-strain response of primary chronic myelogenous leukemia (CML) cells, from two data sets of CD34+ hematopoietic cells isolated from healthy and leukemic bone marrows, we show that the mean shear relaxation modulus increases upon cancer transformation. This stiffening of the cells comes along with local rupture events, detected as reinforced sharp local maxima of this modulus, suggesting that these cancer cells respond to a local mechanical stress by a cascade of local brittle failure events.

  10. Thioredoxin Binding Protein-2 Regulates Autophagy of Human Lens Epithelial Cells under Oxidative Stress via Inhibition of Akt Phosphorylation

    Science.gov (United States)

    Yao, Ke; Zhang, Yidong; Chen, Guangdi; Lai, Kairan; Yin, Houfa

    2016-01-01

    Oxidative stress plays an essential role in the development of age-related cataract. Thioredoxin binding protein-2 (TBP-2) is a negative regulator of thioredoxin (Trx), which deteriorates cellular antioxidant system. Our study focused on the autophagy-regulating effect of TBP-2 under oxidative stress in human lens epithelial cells (LECs). Human lens epithelial cells were used for cell culture and treatment. Lentiviral-based transfection system was used for overexpression of TBP-2. Cytotoxicity assay, western blot analysis, GFP/mCherry-fused LC3 plasmid, immunofluorescence, and transmission electronic microscopy were performed. The results showed that autophagic response of LECs with increased LC3-II, p62, and GFP/mCherry-LC3 puncta (P < 0.01) was induced by oxidative stress. Overexpression of TBP-2 further strengthens this response and worsens the cell viability (P < 0.01). Knockdown of TBP-2 attenuates the autophagic response and cell viability loss induced by oxidative stress. TBP-2 mainly regulates autophagy in the initiation stage, which is mTOR-independent and probably caused by the dephosphorylation of Akt under oxidative stress. These findings suggest a novel role of TBP-2 in human LECs under oxidative stress. Oxidative stress can cause cell injury and autophagy in LECs, and TBP-2 regulates this response. Hence, this study provides evidence regarding the role of TBP-2 in lens and the possible mechanism of cataract development. PMID:27656263

  11. Cell wall pectic arabinans influence the mechanical properties of Arabidopsis thaliana inflorescence stems and their response to mechanical stress.

    Science.gov (United States)

    Verhertbruggen, Yves; Marcus, Susan E; Chen, Jianshe; Knox, J Paul

    2013-08-01

    Little is known of the dynamics of plant cell wall matrix polysaccharides in response to the impact of mechanical stress on plant organs. The capacity of the imposition of a mechanical stress (periodic brushing) to reduce the height of the inflorescence stem of Arabidopsis thaliana seedlings has been used to study the role of pectic arabinans in the mechanical properties and stress responsiveness of a plant organ. The arabinan-deficient-1 (arad1) mutation that affects arabinan structures in epidermal cell walls of inflorescence stems is demonstrated to reduce the impact on inflorescence stem heights caused by mechanical stress. The arabinan-deficient-2 (arad2) mutation, that does not have detectable impact on arabinan structures, is also shown to reduce the impact on stem heights caused by mechanical stress. The LM13 linear arabinan epitope is specifically detected in epidermal cell walls of the younger, flexible regions of inflorescence stems and increases in abundance at the base of inflorescence stems in response to an imposed mechanical stress. The strain (percentage deformation) of stem epidermal cells in the double mutant arad1 × arad2 is lower in unbrushed plants than in wild-type plants, but rises to wild-type levels in response to brushing. The study demonstrates the complexity of arabinan structures within plant cell walls and also that their contribution to cell wall mechanical properties is a factor influencing responsiveness to mechanical stress.

  12. Mécanismes de la peroxydation lipidique et des anti-oxydations

    Directory of Open Access Journals (Sweden)

    Cillard Josiane

    2006-01-01

    Full Text Available Lipid peroxidation is a general phenomenon which takes place in foods as well as in cellular membranes and lipoproteins. It leads to oxidative dammages with consequences to food preservation and to the development of various diseases. The targets of lipid oxidation are the polyunsaturated fatty acids. Owing to the fact that oxygen can exist under 2 states, a ground state (3O2 and an excited state (1O2, lipid peroxidation can proceed by 2 different reactions. One which involves (3O2, is a free-radical chain reaction with 3 steps (initiation by free radicals, propagation and terminaison, the other which involves (1O2 is a fast reaction with direct addition of oxygen to the double bonds of fatty acids. Both reactions lead to the formation of hydroperoxides as primary products. Hydroperoxides decomposed rapidly to give many secondary products such as lipid free radicals which contribute to increase the oxidation of other molecules such as proteins, nucleic acids and other lipids. Ketones, alkanes (pentane, ethane and aldehydes (MDA, 4HNE are also formed by hydroperoxide decomposition. Aldehydes are reactive compounds which bind to the amino group of proteins, nucleic acids and lipids causing dammages to these molecules. The consequences for membranes are alterations of their functions which could lead to cell death. In food hydroperoxide decomposition give rise to qualitative alterations. Lipid peroxidation is a major problem for food industry as well as for human health since it is associated to many diseases. Antioxidants can prevent or delay lipid peroxidation by different mechanisms.

  13. Adaptive responses to osmotic stress in kidney-derived cell lines from Scatophagus argus, a euryhaline fish.

    Science.gov (United States)

    Gui, Lang; Zhang, Peipei; Liang, Xuemei; Su, Maoliang; Wu, Di; Zhang, Junbin

    2016-06-01

    The euryhaline fish, the spotted scat (Scatophagus argus), is exceptional for its ability to tolerate rapid fluctuations in salinity. To better understand fish osmoregulation and enable more precise analyses of specific features of adaptive responses to the osmotic stress in fish, a S. argus kidney-derived cell line (SK) was developed and subcultured for more than 70 passages. The cells were mostly fibroblast-like, with a normal diploid karyotype (2n=48). A low-osmolarity-adapted SK cell line (SK-la) was induced by growth in a hypotonic solution (150 mOsm). Effects of different osmotic stresses (150, 300 and 450 mOsm) on cell growth, cell morphology, cell volume changes and cell damage in SK, SK-la and CIK (a kidney-derived cell line from freshwater grass carp) cells were studied. These were compared by use of microscopic observation, flow cytometry and a Na-K-ATPase (NKA) assay. SK cells became smaller and grew rapidly in response to hypotonic stress (150 mOsm), and exhibited no visible morphological changes in response to hypertonic stress (450 mOsm). SK-la grew well by moderate hypertonicity (300 mOsm) but depressed in severe hypertonicity (450 mOsm), the number of unhealthy SK-la cells rose as osmolarity increased. In contrast, CIK cells became unhealthy with anisotonic challenge. The NKA activities of SK and CIK cells were assayed after exposure to anisotonic conditions, and rapid decreases were detected immediately except SK cells which were not affected in hypotonicity. Unlike in SK and CIK, an increase following a down-regulation of NKA activity was observed in SK-la cells upon moderate hypertonic stress. These results suggested that SK and SK-la cells had stronger osmoregulatory capacity than CIK cells, and provided new insights on the osmosensing and osmotic adaption in euryhaline fish kidney. PMID:26911257

  14. ER-mediated stress induces mitochondrial-dependent caspases activation in NT2 neuron-like cells.

    Science.gov (United States)

    Arduino, Daniela M; Esteves, A Raquel; Domingues, A Filipa; Pereira, Claudia M F; Cardoso, Sandra M; Oliveira, Catarina R

    2009-11-30

    Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

  15. Dexamethasone acts as a radiosensitizer in three astrocytoma cell lines via oxidative stress

    Directory of Open Access Journals (Sweden)

    Sylvia Ortega-Martínez

    2015-08-01

    Full Text Available Glucocorticoids (GCs, which act on stress pathways, are well-established in the co-treatment of different kinds of tumors; however, the underlying mechanisms by which GCs act are not yet well elucidated. As such, this work investigates the role of glucocorticoids, specifically dexamethasone (DEXA, in the processes referred to as DNA damage and DNA damage response (DDR, establishing a new approach in three astrocytomas cell lines (CT2A, APP.PS1 L.1 and APP.PS1 L.3. The results show that DEXA administration increased the basal levels of gamma-H2AX foci, keeping them higher 4 h after irradiation (IR of the cells, compared to untreated cells. This means that DEXA might cause increased radiosensitivity in these cell lines. On the other hand, DEXA did not have an apparent effect on the formation and disappearance of the 53BP1 foci. Furthermore, it was found that DEXA administered 2 h before IR led to a radical change in DNA repair kinetics, even DEXA does not affect cell cycle. It is important to highlight that DEXA produced cell death in these cell lines compared to untreated cells. Finally and most important, the high levels of gamma-H2AX could be reversed by administration of ascorbic acid, a potent blocker of reactive oxygen species, suggesting that DEXA acts by causing DNA damage via oxidative stress. These exiting findings suggest that DEXA might promote radiosensitivity in brain tumors, specifically in astrocytoma-like tumors.

  16. Copper ferrite nanoparticle-induced cytotoxicity and oxidative stress in human breast cancer MCF-7 cells.

    Science.gov (United States)

    Ahamed, Maqusood; Akhtar, Mohd Javed; Alhadlaq, Hisham A; Alshamsan, Aws

    2016-06-01

    Copper ferrite (CuFe2O4) nanoparticles (NPs) are important magnetic materials currently under research due to their applicability in nanomedicine. However, information concerning the biological interaction of copper ferrite NPs is largely lacking. In this study, we investigated the cellular response of copper ferrite NPs in human breast cancer (MCF-7) cells. Copper ferrite NPs were prepared by co-precipitation technique with the thermal effect. Prepared NPs were characterized by X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and dynamic light scattering (DLS). Characterization data showed that copper ferrite NPs were crystalline, spherical with smooth surfaces and average diameter of 15nm. Biochemical studies showed that copper ferrite NPs induce cell viability reduction and membrane damage in MCF-7 cells and degree of induction was dose- and time-dependent. High SubG1 cell population during cell cycle progression and MMP loss with a concomitant up-regulation of caspase-3 and caspase-9 genes suggested that copper ferrite NP-induced cell death through mitochondrial pathway. Copper ferrite NP was also found to induce oxidative stress in MCF-7 cells as indicated by reactive oxygen species (ROS) generation and glutathione depletion. Cytotoxicity due to copper ferrite NPs exposure was effectively abrogated by N-acetyl-cysteine (ROS scavenger) suggesting that oxidative stress could be the plausible mechanism of copper ferrite NPs toxicity. Further studies are underway to explore the toxicity mechanisms of copper ferrite NPs in different types of human cells. This study warrants further generation of extensive biointeraction data before their application in nanomedicine.

  17. The opposite roles of glucocorticoid and α1-adrenergic receptors in stress triggered apoptosis of rat Leydig cells

    OpenAIRE

    Andric, Silvana A.; Kojic, Zvezdana; Bjelic, Maja M.; Mihajlovic, Aleksandar I.; Baburski, Aleksandar Z.; Sokanovic, Srdjan J.; Janjic, Marija M.; Stojkov, Natasa J.; Stanko S Stojilkovic; Kostic, Tatjana S.

    2012-01-01

    The stress-induced initiation of proapoptotic signaling in Leydig cells is relatively well defined, but the duration of this signaling and the mechanism(s) involved in opposing the stress responses have not been addressed. In this study, immobilization stress (IMO) was applied for 2 h daily, and animals were euthanized immediately after the first (IMO1), second (IMO2), and 10th (IMO10) sessions. In IMO1 and IMO2 rats, serum corticosterone and adrenaline were elevated, whereas serum androgens ...

  18. Oxidative stress induces caveolin 1 degradation and impairs caveolae functions in skeletal muscle cells.

    Directory of Open Access Journals (Sweden)

    Alexis Mougeolle

    Full Text Available Increased level of oxidative stress, a major actor of cellular aging, impairs the regenerative capacity of skeletal muscle and leads to the reduction in the number and size of muscle fibers causing sarcopenia. Caveolin 1 is the major component of caveolae, small membrane invaginations involved in signaling and endocytic trafficking. Their role has recently expanded to mechanosensing and to the regulation of oxidative stress-induced pathways. Here, we increased the amount of reactive oxidative species in myoblasts by addition of hydrogen peroxide (H2O2 at non-toxic concentrations. The expression level of caveolin 1 was significantly decreased as early as 10 min after 500 μM H2O2 treatment. This reduction was not observed in the presence of a proteasome inhibitor, suggesting that caveolin 1 was rapidly degraded by the proteasome. In spite of caveolin 1 decrease, caveolae were still able to assemble at the plasma membrane. Their functions however were significantly perturbed by oxidative stress. Endocytosis of a ceramide analog monitored by flow cytometry was significantly diminished after H2O2 treatment, indicating that oxidative stress impaired its selective internalization via caveolae. The contribution of caveolae to the plasma membrane reservoir has been monitored after osmotic cell swelling. H2O2 treatment increased membrane fragility revealing that treated cells were more sensitive to an acute mechanical stress. Altogether, our results indicate that H2O2 decreased caveolin 1 expression and impaired caveolae functions. These data give new insights on age-related deficiencies in skeletal muscle.

  19. Enzymatic Oxydate-Triggered Self-Illuminated Photoelectrochemical Sensing Platform for Portable Immunoassay Using Digital Multimeter.

    Science.gov (United States)

    Shu, Jian; Qiu, Zhenli; Zhou, Qian; Lin, Youxiu; Lu, Minghua; Tang, Dianping

    2016-03-01

    Herein a novel split-type photoelectrochemical (PEC) immunosensing platform was designed for sensitive detection of low-abundance biomarkers (prostate-specific antigen, PSA, used in this case) by coupling a peroxyoxalate chemiluminescence (PO-CL) self-illuminated system with digital multimeter (DMM) readout. The PEC detection device consisted of a capacitor/DMM-joined electronic circuit and a PO-CL-based self-illuminated cell. Initially, reduced graphene oxide-doped BiVO4 (BiVO4-rGO) photovoltaic materials with good photoelectric properties was integrated into the capacitor/DMM-joined circuit for photocurrent generation in the presence of hydrogen peroxide (H2O2, as the hole-trapping reagent). A sandwich-type immunoreaction with target PSA was carried out in capture antibody-coated microplates by using glucose oxidase/detection antibody-conjugating gold nanoparticle (pAb2-AuNP-GOx). Accompanying the sandwiched immunocomplex, the labeled GOx could oxidize glucose to produce H2O2. The as-generated H2O2 could act as the coreaction reagent to trigger the chemiluminescence of the peroxyoxalate system and the PEC reaction of the BiVO4-rGO. Meanwhile, the self-illuminated light could induce photovoltaic material (BiVO4-rGO) to produce a voltage that was utilized to charge an external capacitor. With the switch closed, the capacitor could discharge through the DMM and provide an instantaneous current. Different from conventional PEC immunoassays, the as-generated photoelectron was stored in the capacitor and released instantaneously to amplify the photocurrent. Under the optimal conditions, the transient current increased with the increasing target PSA concentration in the dynamic working range from 10 pg mL(-1) to 80 ng mL(-1) with a detection limit (LOD) of 3 pg mL(-1). This work demonstrated for the first time that the peroxyoxalate CL system could be used as a suitable substitute of physical light source to apply in PEC immunoassay. In addition, this methodology

  20. Enzymatic Oxydate-Triggered Self-Illuminated Photoelectrochemical Sensing Platform for Portable Immunoassay Using Digital Multimeter.

    Science.gov (United States)

    Shu, Jian; Qiu, Zhenli; Zhou, Qian; Lin, Youxiu; Lu, Minghua; Tang, Dianping

    2016-03-01

    Herein a novel split-type photoelectrochemical (PEC) immunosensing platform was designed for sensitive detection of low-abundance biomarkers (prostate-specific antigen, PSA, used in this case) by coupling a peroxyoxalate chemiluminescence (PO-CL) self-illuminated system with digital multimeter (DMM) readout. The PEC detection device consisted of a capacitor/DMM-joined electronic circuit and a PO-CL-based self-illuminated cell. Initially, reduced graphene oxide-doped BiVO4 (BiVO4-rGO) photovoltaic materials with good photoelectric properties was integrated into the capacitor/DMM-joined circuit for photocurrent generation in the presence of hydrogen peroxide (H2O2, as the hole-trapping reagent). A sandwich-type immunoreaction with target PSA was carried out in capture antibody-coated microplates by using glucose oxidase/detection antibody-conjugating gold nanoparticle (pAb2-AuNP-GOx). Accompanying the sandwiched immunocomplex, the labeled GOx could oxidize glucose to produce H2O2. The as-generated H2O2 could act as the coreaction reagent to trigger the chemiluminescence of the peroxyoxalate system and the PEC reaction of the BiVO4-rGO. Meanwhile, the self-illuminated light could induce photovoltaic material (BiVO4-rGO) to produce a voltage that was utilized to charge an external capacitor. With the switch closed, the capacitor could discharge through the DMM and provide an instantaneous current. Different from conventional PEC immunoassays, the as-generated photoelectron was stored in the capacitor and released instantaneously to amplify the photocurrent. Under the optimal conditions, the transient current increased with the increasing target PSA concentration in the dynamic working range from 10 pg mL(-1) to 80 ng mL(-1) with a detection limit (LOD) of 3 pg mL(-1). This work demonstrated for the first time that the peroxyoxalate CL system could be used as a suitable substitute of physical light source to apply in PEC immunoassay. In addition, this methodology

  1. Cytotoxicity and oxidative stress induced by different metallic nanoparticles on human kidney cells

    Directory of Open Access Journals (Sweden)

    Ohayon-Courtès Céline

    2011-03-01

    Full Text Available Abstract Background Some manufactured nanoparticles are metal-based and have a wide variety of applications in electronic, engineering and medicine. Until now, many studies have described the potential toxicity of NPs on pulmonary target, while little attention has been paid to kidney which is considered to be a secondary target organ. The objective of this study, on human renal culture cells, was to assess the toxicity profile of metallic nanoparticles (TiO2, ZnO and CdS usable in industrial production. Comparative studies were conducted, to identify whether particle properties impact cytotoxicity by altering the intracellular oxidative status. Results Nanoparticles were first characterized by size, surface charge, dispersion and solubility. Cytotoxicity of NPs was then evaluated in IP15 (glomerular mesangial and HK-2 (epithelial proximal cell lines. ZnO and CdS NPs significantly increased the cell mortality, in a dose-dependent manner. Cytotoxic effects were correlated with the physicochemical properties of NPs tested and the cell type used. Analysis of reactive oxygen species and intracellular levels of reduced and oxidized glutathione revealed that particles induced stress according to their composition, size and solubility. Protein involved in oxidative stress such as NF-κb was activated with ZnO and CdS nanoparticles. Such effects were not observed with TiO2 nanoparticles. Conclusion On glomerular and tubular human renal cells, ZnO and CdS nanoparticles exerted cytotoxic effects that were correlated with metal composition, particle scale and metal solubility. ROS production and oxidative stress induction clearly indicated their nephrotoxic potential.

  2. Dexmedetomidine Attenuates Oxidative Stress Induced Lung Alveolar Epithelial Cell Apoptosis In Vitro

    Directory of Open Access Journals (Sweden)

    Jian Cui

    2015-01-01

    Full Text Available Background. Oxidative stress plays a pivotal role in the lung injuries of critical ill patients. This study investigates the protection conferred by α2 adrenoceptor agonist dexmedetomidine (Dex from lung alveolar epithelial cell injury induced by hydrogen peroxide (H2O2 and the underlying mechanisms. Methods. The lung alveolar epithelial cell line, A549, was cultured and then treated with 500 μM H2O2 with or without Dex (1 nM or Dex in combination with atipamezole (10 nM, an antagonist of α2 receptors. Their effect on mitochondrial membrane potential (Δψm, reactive oxygen species (ROS, and the cell cycle was assessed by flow cytometry. Cleaved-caspases 3 and 9, BAX, Bcl-2, phospho-mTOR (p-mTOR, ERK1/2, and E-cadherin expression were also determined with immunocytochemistry. Results. Upregulation of cleaved-caspases 3 and 9 and BAX and downregulation of Bcl-2, p-mTOR, and E-cadherin were found following H2O2 treatment, and all of these were reversed by Dex. Dex also prevented the ROS generation, cytochrome C release, and cell cycle arrest induced by H2O2. The effects of Dex were partially reversed by atipamezole. Conclusion. Our study demonstrated that Dex protected lung alveolar epithelial cells from apoptotic injury, cell cycle arrest, and loss of cell adhesion induced by H2O2 through enhancing the cell survival and proliferation.

  3. Effect of Astragalus Polysaccharide on the Cell-mediated Immunity of Traumatic Stress Mice

    Institute of Scientific and Technical Information of China (English)

    曾广仙; 熊金蓉; 刘俊英; 廖奕华; 代丽红; 李杏娟; 沈关心

    2004-01-01

    To investigate the changes of immune functions and the effects of Astragaius polysaccharide (ASP) on the cell-mediated immunity of the traumatic stress model of mouse by amputation, 50 mice were randomly divided into 5 groups for study, in which the group A and B served as the normal control (by injecton of 0.5 ml of saline intra-peritoneally daily), and as the stress control (by intra-peritoneal injecton of 0.5 ml of normal saline into mice after amputation) respectively, to the group C, D and E of mice, 1000 mg/kg (high dose), 300 mg/kg (median dose) and 250 mg/kg (low dose). The CD4+ and CD8+ T cells as well as the expression of the c-fos protein were determined by immunohistochemical techniques, and the expressions of NF-κB mRNA and IL-10 mRNA were assayed by hybridization in situ. The experimental results showed that in comparison with the normal control group of mice (group A), the expression levels of NF-κB mRNA, IL-10 mRNA and the c-fos protein in the tissues of thymus and spleen in the stress controls were significantly elevated and the CD4+ T cells and CD4/CD8 ratio were decreased. However, in comparison with the stress control of mice (group B), the expressions of NF-κB mRNA and IL-10 mRNA were inhibited by ASP, and the CD4+ T cells and CD4/CD8 ratio were increased in groups C, D and E, but the level of c-fos protein was decreased. There was no significant difference in these parameters among group C, D and E. It is con-cluded that the functions of cell-mediated immunity of mice were disturbed under the stress condition of the traumatic injuries after amputation. And the immune functions can be effectively restored by the use of Astraga/us polysaccharide.

  4. Dynamic deformation capability of a red blood cell under a cyclically reciprocating shear stress.

    Science.gov (United States)

    Watanabe, N; Yasuda, T; Kataoka, H; Takatani, S

    2004-01-01

    Red blood cells (RBCs) in the cardiovascular devices are exposed to varying degree of the shear stress from all the directions. However the RBCs' deformability or the deformation capability under such a shear stress is not well understood. In this study, we designed and built a system that can induce a cyclically reciprocating shear stress to a RBC suspension. The arm of the cyclically reciprocating shear stress device was attached to the upper piece of the parallel glass plates between which a suspension of human RBCs (1% hematocrit whole blood diluted in a 32 weight% dextran phosphate buffer solution) was contained. The cyclic reciprocating motion of the upper glass plate of 3.0 mm stroke length was produced using a slider-crank shaft mechanism that was linked to an eccentric cam-motor system. Each rotation of the motor produced a 3.0 mm stroke each in the forward and backward direction of the slider block. The clearance between the two glass plates was adjusted to 30 micrometer. The cyclic reciprocating glass plate apparatus was attached to a light microscope stage (IX71 Olympus with x40 objective lens) for illumination with a 350 watt metal halide light source. A high speed camera (MEMREMCAM fx-K3 Nac, 5000 frames per second with shutter kept open) was attached to the microscope to capture the deformation process of the RBCs under cyclic shear stress. The preliminary result indicated that the correlation between the amplitude of the maximum shear stress and the RBCs' deformability. This indicates a potential application of the cyclic reciprocating device to evaluate the temporal response of the RBCs deformability prior to its destruction. The future study will focus on the study of the relative velocity of the erythrocytes with respect to the velocity of the reciprocating plate. PMID:17271457

  5. Introduction of Pea DNA Helicase 45 Into Sugarcane (Saccharum spp. Hybrid) Enhances Cell Membrane Thermostability And Upregulation Of Stress-responsive Genes Leads To Abiotic Stress Tolerance.

    Science.gov (United States)

    Augustine, Sruthy Maria; Ashwin Narayan, J; Syamaladevi, Divya P; Appunu, C; Chakravarthi, M; Ravichandran, V; Tuteja, Narendra; Subramonian, N

    2015-05-01

    DNA helicases are motor proteins that play an essential role in nucleic acid metabolism, by providing a duplex-unwinding function. To improve the drought and salinity tolerance of sugarcane, a DEAD-box helicase gene isolated from pea with a constitutive promoter, Port Ubi 2.3 was transformed into the commercial sugarcane variety Co 86032 through Agrobacterium-mediated transformation, and the transgenics were screened for tolerance to soil moisture stress and salinity. The transgene integration was confirmed through polymerase chain reaction, and the V 0 transgenic events showed significantly higher cell membrane thermostability under normal irrigated conditions. The V 1 transgenic events were screened for tolerance to soil moisture stress and exhibited significantly higher cell membrane thermostability, transgene expression, relative water content, gas exchange parameters, chlorophyll content, and photosynthetic efficiency under soil moisture stress compared to wild-type (WT). The overexpression of PDH45 transgenic sugarcane also led to the upregulation of DREB2-induced downstream stress-related genes. The transgenic events demonstrated higher germination ability and better chlorophyll retention than WT under salinity stress. Our results suggest the possibility for development of increased abiotic stress tolerant sugarcane cultivars through overexpression of PDH45 gene. Perhaps this is the first report, which provides evidence for increased drought and salinity tolerance in sugarcane through overexpression of PDH45.

  6. Salt stress response triggers activation of the jasmonate signaling pathway leading to inhibition of cell elongation in Arabidopsis primary root.

    Science.gov (United States)

    Valenzuela, Camilo E; Acevedo-Acevedo, Orlando; Miranda, Giovanna S; Vergara-Barros, Pablo; Holuigue, Loreto; Figueroa, Carlos R; Figueroa, Pablo M

    2016-07-01

    Salinity is a severe abiotic stress that affects irrigated croplands. Jasmonate (JA) is an essential hormone involved in plant defense against herbivory and in responses to abiotic stress. However, the relationship between the salt stress response and the JA pathway in Arabidopsis thaliana is not well understood at molecular and cellular levels. In this work we investigated the activation of JA signaling by NaCl and its effect on primary root growth. We found that JA-responsive JAZ genes were up-regulated by salt stress in a COI1-dependent manner in the roots. Using a JA-Ile sensor we demonstrated that activation of JA signaling by salt stress occurs in the meristematic zone and stele of the differentiation zone and that this activation was dependent on JAR1 and proteasome functions. Another finding is that the elongation zone (EZ) and its cortical cells were significantly longer in JA-related mutants (AOS, COI1, JAZ3 and MYC2/3/4 genes) compared with wild-type plants under salt stress, revealing the participation of the canonical JA signaling pathway. Noteworthy, osmotic stress - a component of salt stress - inhibited cell elongation in the EZ in a COI1-dependent manner. We propose that salt stress triggers activation of the JA signaling pathway followed by inhibition of cell elongation in the EZ. We have shown that salt-inhibited root growth partially involves the jasmonate signaling pathway in Arabidopsis. PMID:27217545

  7. Cell wall yield properties of growing tissue: evaluation by in vivo stress relaxation. [Pisum sativus L

    Energy Technology Data Exchange (ETDEWEB)

    Cosgrove, D.J.

    1985-06-01

    Growing pea stem tissue, when isolated from an external supply of water, undergoes stress relaxation because of continued loosening of the cell wall. A theoretical analysis is presented to show that such stress relaxation should result in an exponential decrease in turgor pressure down to the yield threshold (Y), with a rate constant given by phi epsilon where phi is the metabolically maintained irreversible extensibility of the cell wall and epsilon is the volumetric elastic modulus of the cell. Stress relaxation was measured in pea (Pisum sativus L.) stem segments using the pressure microprobe technique. From the rate of stress relaxation, phi of segments pretreated with water was calculated to be 0.08 per megapascal per hour while that of auxin-pretreated tissue was 0.24 per megapascal per hour. These values agreed closely with estimates of phi made by a steady-state technique. The yield threshold (0.29 megapascal) was not affected by auxin. A theoretical analysis is also presented to show that the tissue hydraulic conductance may be estimated from the T/sub 1/2/ of tissue swelling. Experimentally, pea stems had a swelling T/sub 1/2/ of 2.0 minutes, corresponding to a relative hydraulic conductance of about 2.0 per megapascal per hour. This value is at least 8 times larger than phi. From these data and from computer modeling, it appears that the radial gradient in water potential which sustains water uptake in growing pea segments is small (0.04 megapascal). This means that hydraulic conductance does not substantially restrict growth. The results also demonstrate that the stimulation of growth by auxin can be entirely accounted for by the change in phi.

  8. Etude paramétrique des effets de la stratification de la flamme sur les émissions d'oxydes d'azote (deuxième partie Parametric Study of Stratification Effects on Nitric Oxide Emissions from Flames (Part Two

    Directory of Open Access Journals (Sweden)

    De Soete G.

    2006-11-01

    Full Text Available On a étudié les effets de la stratification de flammes de prémélange laminaires, stationnaires et non stationnaires, sur les émissions d'oxydes d'azote formés par le mécanisme thermique et par le mécanisme du fuel-NO. Deux modalités de stratification ont été considérées, l'une juxtaposant sur le même plan les zones de combustion primaires correspond aux fractions individuelles du mélange stratifié (stratification en juxtaposition, l'autre disposant ces zones de combustion primaires sur des plans successifs (stratification en succession. Les émissions d'oxydes d'azote mesurées sur les flammes stratifiées ont été comparées à celles provenant de flammes non stratifiées de même composition globale et brûlant dans des conditions identiques. L'étude montre qu'il y a lieu de distinguer deux types d'effets de stratification. II existe un effet primaire qui est la simple conséquence du morcellement de la flamme en un certain nombre de zones de combustion primaires (caractérisées par des compositions différentes/ et qui se traduit par l'additivité des émissions individuelles provenant des fractions respectives du mélange. L'effet total de la stratification se réduit à ce seul effet primaire au cas où les vitesses de formation des oxydes d'azote deviennent nulles après re-mélange des produits de combustion provenant des différentes fractions du mélange stratifié. fi' en est ainsi par exempte dans le cas des flammes non stationnaires stratifiées en succession; il en résulte alors soit une augmentation soit une diminution des émissions d'oxydes d'azote par rapport à celles des flammes non stratifiées, suivant la valeur de la richesse globale et du degré de stratification. Des effets secondaires de stratification se manifestent chaque fois que des produits de combustion, provenant d'une zone de combustion primaire donnée, sont introduits totalement ou partiellement dans un autre front de flamme créé par la

  9. The NG2 Proteoglycan Protects Oligodendrocyte Precursor Cells against Oxidative Stress via Interaction with OMI/HtrA2.

    Directory of Open Access Journals (Sweden)

    Frank Maus

    Full Text Available The NG2 proteoglycan is characteristically expressed by oligodendrocyte progenitor cells (OPC and also by aggressive brain tumours highly resistant to chemo- and radiation therapy. Oligodendrocyte-lineage cells are particularly sensitive to stress resulting in cell death in white matter after hypoxic or ischemic insults of premature infants and destruction of OPC in some types of Multiple Sclerosis lesions. Here we show that the NG2 proteoglycan binds OMI/HtrA2, a mitochondrial serine protease which is released from damaged mitochondria into the cytosol in response to stress. In the cytosol, OMI/HtrA2 initiates apoptosis by proteolytic degradation of anti-apoptotic factors. OPC in which NG2 has been downregulated by siRNA, or OPC from the NG2-knockout mouse show an increased sensitivity to oxidative stress evidenced by increased cell death. The proapoptotic protease activity of OMI/HtrA2 in the cytosol can be reduced by the interaction with NG2. Human glioma expressing high levels of NG2 are less sensitive to oxidative stress than those with lower NG2 expression and reducing NG2 expression by siRNA increases cell death in response to oxidative stress. Binding of NG2 to OMI/HtrA2 may thus help protect cells against oxidative stress-induced cell death. This interaction is likely to contribute to the high chemo- and radioresistance of glioma.

  10. Albumin-bound fatty acids induce mitochondrial oxidant stress and impair antioxidant responses in proximal tubular cells

    NARCIS (Netherlands)

    Ishola, D. A.; Post, J. A.; van Timmeren, M. M.; Bakker, S. J. L.; Goldschmeding, R.; Koomans, H. A.; Braam, B.; Joles, J. A.

    2006-01-01

    Albumin induces oxidative stress and cytokine production in proximal tubular cells (PTECs). Albumin-bound fatty acids (FAs) enhance tubulopathic effects of albumin in vivo. We proposed that FA aggravation of albumin-induced oxidative stress in PTECs might be involved. We hypothesized that mitochondr

  11. Oxidative Stress in Retinal Muller Cells contributes to Dysfunction of Retinal Glutamate Uptake and Altered Protein Expression

    DEFF Research Database (Denmark)

    Toft-Kehler, Anne Katrine; Skytt, Dorte Marie; Kolko, Miriam

    2015-01-01

    minor, though significant, reduction of cell viability was seen after 1 and 24 hours of exposure to oxidative stress. The glutamate transporter, EAAT1, was significantly up-regulated at RNA-level after exposure to oxidative stress, whereas the alterations of superoxide dismutase 2 (SOD2) was time...

  12. Reactive oxygen species regulate leaf pulvinus abscission zone cell separation in response to water-deficit stress in cassava.

    Science.gov (United States)

    Liao, Wenbin; Wang, Gan; Li, Yayun; Wang, Bin; Zhang, Peng; Peng, Ming

    2016-01-01

    Cassava (Manihot esculenta Crantz) plant resists water-deficit stress by shedding leaves leading to adaptive water-deficit condition. Transcriptomic, physiological, cellular, molecular, metabolic, and transgenic methods were used to study the mechanism of cassava abscission zone (AZ) cell separation under water-deficit stress. Microscopic observation indicated that AZ cell separation initiated at the later stages during water-deficit stress. Transcriptome profiling of AZ suggested that differential expression genes of AZ under stress mainly participate in reactive oxygen species (ROS) pathway. The key genes involved in hydrogen peroxide biosynthesis and metabolism showed significantly higher expression levels in AZ than non-separating tissues adjacent to the AZ under stress. Significantly higher levels of hydrogen peroxide correlated with hydrogen peroxide biosynthesis related genes and AZ cell separation was detected by microscopic observation, colorimetric detection and GC-MS analyses under stress. Co-overexpression of the ROS-scavenging proteins SOD and CAT1 in cassava decreased the levels of hydrogen peroxide in AZ under water-deficit stress. The cell separation of the pulvinus AZ also delayed in co-overexpression of the ROS-scavenging proteins SOD and CAT1 plants both in vitro and at the plant level. Together, the results indicated that ROS play an important regulatory role in the process of cassava leaf abscission under water-deficit stress.

  13. Reactive oxygen species regulate leaf pulvinus abscission zone cell separation in response to water-deficit stress in cassava.

    Science.gov (United States)

    Liao, Wenbin; Wang, Gan; Li, Yayun; Wang, Bin; Zhang, Peng; Peng, Ming

    2016-01-01

    Cassava (Manihot esculenta Crantz) plant resists water-deficit stress by shedding leaves leading to adaptive water-deficit condition. Transcriptomic, physiological, cellular, molecular, metabolic, and transgenic methods were used to study the mechanism of cassava abscission zone (AZ) cell separation under water-deficit stress. Microscopic observation indicated that AZ cell separation initiated at the later stages during water-deficit stress. Transcriptome profiling of AZ suggested that differential expression genes of AZ under stress mainly participate in reactive oxygen species (ROS) pathway. The key genes involved in hydrogen peroxide biosynthesis and metabolism showed significantly higher expression levels in AZ than non-separating tissues adjacent to the AZ under stress. Significantly higher levels of hydrogen peroxide correlated with hydrogen peroxide biosynthesis related genes and AZ cell separation was detected by microscopic observation, colorimetric detection and GC-MS analyses under stress. Co-overexpression of the ROS-scavenging proteins SOD and CAT1 in cassava decreased the levels of hydrogen peroxide in AZ under water-deficit stress. The cell separation of the pulvinus AZ also delayed in co-overexpression of the ROS-scavenging proteins SOD and CAT1 plants both in vitro and at the plant level. Together, the results indicated that ROS play an important regulatory role in the process of cassava leaf abscission under water-deficit stress. PMID:26899473

  14. Localization of NG2 immunoreactive neuroglia cells in the rat locus coeruleus and their plasticity in response to stress

    NARCIS (Netherlands)

    Seifi, Mohsen; Corteen, Nicole L.; van der Want, Johannes; Metzger, Friedrich; Swinny, Jerome D.

    2014-01-01

    The locus coeruleus (LC) nucleus modulates adaptive behavioral responses to stress and dysregulation of LC neuronal activity is implicated in stress-induced mental illnesses. The LC is composed primarily of noradrenergic neurons together with various glial populations. A neuroglia cell-type largely

  15. Oxidative stress induced Interleukin-32 mRNA expression in human bronchial epithelial cells

    Directory of Open Access Journals (Sweden)

    Kudo Megumi

    2012-03-01

    Full Text Available Abstract Background Chronic obstructive pulmonary disease (COPD is characterized by airflow obstruction and persistent inflammation in the airways and lung parenchyma. Oxidative stress contributes to the pathogenesis of COPD. Interleukin (IL-32 expression has been reported to increase in the lung tissue of patients with COPD. Here, we show that IFNγ upregulated IL-32 expression and that oxidative stress augmented IFNγ-induced-IL-32 expression in airway epithelial cells. We further investigated transcriptional regulation responsible for IFNγ induced IL-32 expression in human airway epithelial cells. Methods Human bronchial epithelial (HBE cells were stimulated with H2O2 and IFNγ, and IL-32 expression was evaluated. The cell viability was confirmed by MTT assay. The intracellular signaling pathways regulating IL-32 expression were investigated by examining the regulatory effects of MAPK inhibitors and JAK inhibitor after treatment with H2O2 and IFNγ, and by using a ChIP assay to identify transcription factors (i.e. c-Jun, CREB binding to the IL-32 promoter. Promoter activity assays were conducted after mutations were introduced into binding sites of c-Jun and CREB in the IL-32 promoter. IL-32 expression was also examined in HBE cells in which the expression of either c-Jun or CREB was knocked out by siRNA of indicated transcription factors. Results There were no significant differences of cell viability among groups. After stimulation with H2O2 or IFNγ for 48 hours, IL-32 expression in HBE cells was increased by IFNγ and synergistically upregulated by the addition of H2O2. The H2O2 augmented IFNγ induced IL-32 mRNA expression was suppressed by a JNK inhibitor, but not by MEK inhibitor, p38 inhibitor, and JAK inhibitor I. Significant binding of c-Jun and CREB to the IL-32 promoter was observed in the IFNγ + H2O2 stimulated HBE cells. Introducing mutations into the c-Jun/CREB binding sites in the IL-32 promoter prominently suppressed its

  16. Oxidative stress and apoptosis in intrinsic renal cell populations - an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Gobe, G.C.; Hogg, N.; Schoch, E.; James, M.; Willgoss, D.; Endre, Z. [University of Queensland, Brisbane, QLD (Australia)

    1996-12-31

    The authors have been studying the interaction between incidence of apoptosis and expression of selected oncogenes and cytokines in an in vivo rat model of ischaemia-reperfusion injury. The ischaemia itself, and the reperfusion, induce oxidative damage to the tissues, including damage from oxygen-derived free radicals. The scenario is therefore similar to radiation-induced injury. The proximal nephron segments, especially the pars recta, are usually acutely sensitive to ischaemia-reperfusion injury, undergoing necrosis in preference to apoptosis. A hypothesis was formed that Bcl-2 protection of the distal nephron, a segment of the nephron known as a reservoir for many growth factors or cytokines, allows increased production of growth factors during oxidative stress, which then act in a paracrine manner to protect the nearby proximal tubule. To test this hypothesis, an in vitro model of oxidative stress was used on either distal (Madin Derby Canine Kidney, MDCK) or proximal (human kidney-2, HK-2) established renal cell lines. We grow the cells as `coverslip cultures` in 12-well plates in Dulbecco`s Modified Eagle`s Medium or serum free medium. The treatments used are either hydrogen peroxide (a gradation of concentrations from 1mM to 50 mM), tumour necrosis factor-alpha (TNF-alpha) or hypoxia, as inducers of oxidative stress. The parameters analysed in the present study were (i) cell death (apoptosis or necrosis, using histology, in situ end labelling, and electron microscopy) (ii) cell proliferation and (iii) Bcl-2 expression (immunohistochemistry). It was found that all treatments increase levels of apoptosis in both cell lines, and TNF-alpha also causes increased cell proliferation. At the higher concentrations of hydrogen peroxide however, the HK-2 (proximal) cells have more of a tendency to undergo necrosis than do the MDCK (distal) cells, mimicking the in vivo situation. Bcl-2 expression is low in both cell lines, and does not appear to be affected by the

  17. Oxidative stress and apoptosis in intrinsic renal cell populations - an in vitro study

    International Nuclear Information System (INIS)

    The authors have been studying the interaction between incidence of apoptosis and expression of selected oncogenes and cytokines in an in vivo rat model of ischaemia-reperfusion injury. The ischaemia itself, and the reperfusion, induce oxidative damage to the tissues, including damage from oxygen-derived free radicals. The scenario is therefore similar to radiation-induced injury. The proximal nephron segments, especially the pars recta, are usually acutely sensitive to ischaemia-reperfusion injury, undergoing necrosis in preference to apoptosis. A hypothesis was formed that Bcl-2 protection of the distal nephron, a segment of the nephron known as a reservoir for many growth factors or cytokines, allows increased production of growth factors during oxidative stress, which then act in a paracrine manner to protect the nearby proximal tubule. To test this hypothesis, an in vitro model of oxidative stress was used on either distal (Madin Derby Canine Kidney, MDCK) or proximal (human kidney-2, HK-2) established renal cell lines. We grow the cells as 'coverslip cultures' in 12-well plates in Dulbecco's Modified Eagle's Medium or serum free medium. The treatments used are either hydrogen peroxide (a gradation of concentrations from 1mM to 50 mM), tumour necrosis factor-alpha (TNF-alpha) or hypoxia, as inducers of oxidative stress. The parameters analysed in the present study were (i) cell death (apoptosis or necrosis, using histology, in situ end labelling, and electron microscopy) (ii) cell proliferation and (iii) Bcl-2 expression (immunohistochemistry). It was found that all treatments increase levels of apoptosis in both cell lines, and TNF-alpha also causes increased cell proliferation. At the higher concentrations of hydrogen peroxide however, the HK-2 (proximal) cells have more of a tendency to undergo necrosis than do the MDCK (distal) cells, mimicking the in vivo situation. Bcl-2 expression is low in both cell lines, and does not appear to be affected by the

  18. Water Stress Effect on Cell Wall Components of Maize (Zea mays Bran

    Directory of Open Access Journals (Sweden)

    Eleazar LUGO-CRUZ

    2016-03-01

    Full Text Available In México, around 82% of the total production of maize is grown under rainfed conditions leading to a water stress environment which affects physiologic and biochemical process of the plant. Maize bran is a composited plant material consisting mainly in aleurone layer, testa and pericarp; the cell walls of these tissues are composed of proteins, non-starch polysaccharides, phenolic acids and lignin which are potential bioactive substances for human nutrition. In this research it was investigated the effect of water stress on cell wall components in the bran of three genotypes of maize by applying irrigation and water stress treatments. The content of protein, lignin, arabinoxylans, total phenols and phenolic acids was performed in the bran of ʽCebúʼ, ʽDK2027ʼ and ʽDK2034ʼ genotypes. Water stress applied through grain development stage increased protein levels of ʽCebúʼ, ʽDK2027ʼ and ʽDK2034ʼ in 4.05, 16.13 and 0.40% respectively. Respecting to lignin content, water stress increased levels at 1.28, 2.26 and 4.24% for ʽCebúʼ, ʽDK2027ʼ and ʽDK2034ʼ, respectively. Arabinoxylans content also increased in water stress treatment at levels of 1.28, 2.26 and 3.66% in ʽCebúʼ, ʽDK2027ʼ and ʽDK2034ʼ. On the other hand, water stress treatment decreased the levels of total phenols and hydroxycinnamic acids in the three maize hybrids analysed. Reduction of total phenols was 35.34, 5.59 and 31.57% for ʽCebúʼ, ʽDK2027ʼ and ʽDK2034ʼ, respectively. In addition, the levels of t-ferulic, c-ferulic and p-coumaric acids decreased 17.74, 23.93, 29.83% in ʽCebúʼ, 8.92, 8.62, 24.03% in ʽDK2027ʼ and 13.66, 11.03, 10.38% in ʽDK2034ʼ respectively.

  19. Thermal stress management of a solid oxide fuel cell using neural network predictive control

    International Nuclear Information System (INIS)

    In SOFC (solid oxide fuel cell) systems operating at high temperatures, temperature fluctuation induces a thermal stress in the electrodes and electrolyte ceramics; therefore, the cell temperature distribution is recommended to be kept as constant as possible. In the present work, a mathematical model based on first principles is presented to avert such temperature fluctuations. The fuel cell running on ammonia is divided into five subsystems and factors such as mass/energy/momentum transfer, diffusion through porous media, electrochemical reactions, and polarization losses inside the subsystems are presented. Dynamic cell-tube temperature responses of the cell to step changes in conditions of the feed streams is investigated. The results of simulation indicate that the transient response of the SOFC is mainly influenced by the temperature dynamics. It is also shown that the inlet stream temperatures are associated with the highest long term start-up time (467 s) among other parameters in terms of step changes. In contrast the step change in fuel velocity has the lowest influence on the start-up time (about 190 s from initial steady state to the new steady state) among other parameters. A NNPC (neural network predictive controller) is then implemented for thermal stress management by controlling the cell tube temperature to avoid performance degradation by manipulating the temperature of the inlet air stream. The regulatory performance of the NNPC is compared with a PI (proportional–integral) controller. The performance of the control system confirms that NNPC is a non-linear-model-based strategy which can assure less oscillating control responses with shorter settling times in comparison to the PI controller. - Highlights: • Effect of the operating parameters on the fuel cell temperature is analysed. • A neural network predictive controller (NNPC) is implemented. • The performance of NNPC is compared with the PI controller. • A detailed model is used for

  20. Proteasome inhibitor MG-132 induces C6 glioma cell apoptosis via oxidative stress

    Institute of Scientific and Technical Information of China (English)

    Wen-hai FAN; Yi HOU; Fan-kai MENG; Xiao-fei WANG; Yi-nan LUO; Peng-fei GE

    2011-01-01

    Aim: Proteasome inhibitors have been found to suppress gtioma cell proliferation and induce apoptosis, but the mechanisms are not fully elucidated. In this study we investigated the mechanisms underlying the apoptosis induced by the proteasome inhibitor MG-132 in glioma cells.Methods: C6 glioma cells were used. MTF assay was used to analyze cell proliferation. Proteasome activity was assayed using Succi-nyI-LLVY-AMC, and intracellular ROS level was evaluated with the redox-sensitive dye DCFH-DA. Apoptosis was detected using fluores-cence and transmission electron microscopy as well as flow cytometry. The expression of apoptosis-related proteins was investigated using Western blot analysis.Results: MG-132 inhibited C6 glioma cell proliferation in a time- and dose-dependent manner (the IC value at 24 h was 18.5 μmol/L). MG-132 (18.5 μmol/L) suppressed the proteasome activity by about 70% at 3 h. It induced apoptosis via down-regulation of antiapop-totic proteins Bcl-2 and XlAP0 up-regulation of pro-apoptotic protein Bax and caspase-3, and production of cleaved C-terminal 85 kDa PARP). It also caused a more than 5-fold increase of reactive oxygen species. Tiron (1 mmol/L) effectively blocked oxidative stress induced by MG-132 (18.5 pmol/L), attenuated proliferation inhibition and apoptosis in C6 glioma cells, and reversed the expression pattern of apoptosis-related proteins.Conclusion: MG-132 induced apoptosis of C6 glioma cells via the oxidative stress.

  1. Growth promoting effects of prebiotic yeast cell wall products in starter broilers under an immune stress and Clostridium perfringens challenge

    Science.gov (United States)

    This study was designed to investigate the growth promoting effects of supplementing different sources and concentrations of prebiotic yeast cell wall (YCW) products containing mannanoligosaccharides in starter broilers under an immune stress and Clostridium perfringens challenge. Through a series ...

  2. Tart Cherry Extracts Reduce Inflammatory and Oxidative Stress Signaling in Microglial Cells.

    Science.gov (United States)

    Shukitt-Hale, Barbara; Kelly, Megan E; Bielinski, Donna F; Fisher, Derek R

    2016-01-01

    Tart cherries contain an array of polyphenols that can decrease inflammation and oxidative stress (OS), which contribute to cognitive declines seen in aging populations. Previous studies have shown that polyphenols from dark-colored fruits can reduce stress-mediated signaling in BV-2 mouse microglial cells, leading to decreases in nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression. Thus, the present study sought to determine if tart cherries-which improved cognitive behavior in aged rats-would be efficacious in reducing inflammatory and OS signaling in HAPI rat microglial cells. Cells were pretreated with different concentrations (0-1.0 mg/mL) of Montmorency tart cherry powder for 1-4 h, then treated with 0 or 100 ng/mL lipopolysaccharide (LPS) overnight. LPS application increased extracellular levels of NO and tumor necrosis factor-alpha (TNF-α), and intracellular levels of iNOS and cyclooxygenase-2 (COX-2). Pretreatment with tart cherry decreased levels of NO, TNF-α, and COX-2 in a dose- and time-dependent manner versus those without pretreatment; the optimal combination was between 0.125 and 0.25 mg/mL tart cherry for 2 h. Higher concentrations of tart cherry powder and longer exposure times negatively affected cell viability. Therefore, tart cherries (like other dark-colored fruits), may be effective in reducing inflammatory and OS-mediated signals. PMID:27669317

  3. Etoposide Induces Apoptosis in Activated Human Hepatic Stellate Cells via ER Stress

    Science.gov (United States)

    Wang, Chen; Zhang, Feng; Cao, Yu; Zhang, Mingming; Wang, Aixiu; Xu, Mingcui; Su, Min; Zhang, Ming; Zhuge, Yuzheng

    2016-01-01

    The activation of hepatic stellate cells (HSCs) plays a vital role in the progression of liver fibrosis, and the induction of HSCs apoptosis may attenuate or reverse fibrogenesis. The therapeutic effects of etoposide(VP-16), a widely used anticancer agent, on HSCs apoptosis and liver fibrosis resolution are still unclear. Here, we report that VP-16 reduced the proliferation of LX-2 cells and led to significantly high levels of apoptosis, as indicated by Annexin V staining and the proteolytic cleavage of the executioner caspase-3 and PARP. Additionally, the unfolded protein response regulators CHOP, BIP, caspase-12, p-eIF2α and IRE1α, which are considered endoplasmic reticulum (ER) stress markers, were upregulated by VP-16. The strong inhibitory effect of VP-16 on LX-2 cells was mainly dependent on ER stress, which activated JNK signaling pathway. Remarkably, VP-16 treatment decreased the expression of α-SMA and type I collagen and simultaneously increased the ratio of matrix metalloproteinases (MMPs) to tissue inhibitor of matrix metalloproteinases (TIMPs). In contrast, VP-16 induced significantly more apoptosis in HSCs than in normal hepatocytes. Taken together, our findings demonstrate that VP-16 exerts a proapoptotic effect on LX-2 cells and has an antifibrogenic effect on collagen deposition, suggesting a new strategy for the treatment of liver fibrosis. PMID:27680712

  4. Increased response to oxidative stress challenge of nano-copper-induced apoptosis in mesangial cells

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Pengjuan; Li, Zhigui; Zhang, Xiaochen; Yang, Zhuo, E-mail: zhuoyang@nankai.edu.cn [Nankai University, College of Medicine, State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Tumor Microenvironment and Neurovascular Regulation (China)

    2014-12-15

    Recently, many studies reported that nanosized copper particles (nano-Cu, the particle size was around 15–30 nm), one of the nanometer materials, could induce nephrotoxicity. To detect the effect of nano-Cu on mesangial cells (MCs), and investigate the underlying mechanism, MCs were treated with different concentrations of nano-Cu (1, 10, and 30 μg/mL) to determine the oxidative stress and apoptotic changes. It was revealed that nano-Cu could induce a decreased viability in MCs together with a significant increase in the number of apoptotic cells by using cell counting kit-8 assay and flow cytometry. The apoptotic morphological changes induced by nano-Cu in MCs were demonstrated by Hochest33342 staining. Results showed that nano-Cu induced the nuclear fragmentation in MCs. Meanwhile, nano-Cu significantly increased the levels of reactive oxygen species, especially increased the levels of H{sub 2}O{sub 2}. It also decreased the activity of total SOD enzyme. In addition, when pre-treated with N-(2-mercaptopropionyl)-glycine, the cell apoptosis induced by nano-Cu was significantly decreased. These results suggest that oxidative stress plays an important role in the nano-Cu toxicity in MCs, which may be the main mechanism of nano-Cu-induced nephrotoxicity.

  5. Preconditioning L6 Muscle Cells with Naringin Ameliorates Oxidative Stress and Increases Glucose Uptake.

    Directory of Open Access Journals (Sweden)

    R Dhanya

    Full Text Available Enhanced oxidative stress contributes to pathological changes in diabetes and its complications. Thus, strategies to reduce oxidative stress may alleviate these pathogenic processes. Herein, we have investigated Naringin mediated regulation of glutathione (GSH & intracellular free radical levels and modulation of glucose uptake under oxidative stress in L6 cell lines. The results from the study demonstrated a marked decrease in glutathione with a subsequent increase in free radical levels, which was reversed by the pretreatment of Naringin. We also observed that the increased malondialdehyde level, the marker of lipid peroxidation on induction of oxidative stress was retrieved on Naringin pretreatment. Addition of Naringin (100 μM showed approximately 40% reduction in protein glycation in vitro. Furthermore, we observed a twofold increase in uptake of fluorescent labeled glucose namely 2-(N-(7-Nitrobenz-2-oxa-1,3-diazol-4-ylAmino-2-Deoxyglucose (2-NBDG on Naringin treatment in differentiated L6 myoblast. The increased uptake of 2-NBDG by L6 myotubes may be attributed due to the enhanced translocation of GLUT4. Our results demonstrate that Naringin activate GSH synthesis through a novel antioxidant defense mechanism against excessive Reactive Oxygen Species (ROS production, contributing to the prevention of oxidative damage in addition to its effect on glycemic control.

  6. Deciphering early events involved in hyperosmotic stress-induced programmed cell death in tobacco BY-2 cells.

    Science.gov (United States)

    Monetti, Emanuela; Kadono, Takashi; Tran, Daniel; Azzarello, Elisa; Arbelet-Bonnin, Delphine; Biligui, Bernadette; Briand, Joël; Kawano, Tomonori; Mancuso, Stefano; Bouteau, François

    2014-03-01

    Hyperosmotic stresses represent one of the major constraints that adversely affect plants growth, development, and productivity. In this study, the focus was on early responses to hyperosmotic stress- (NaCl and sorbitol) induced reactive oxygen species (ROS) generation, cytosolic Ca(2+) concentration ([Ca(2+)]cyt) increase, ion fluxes, and mitochondrial potential variations, and on their links in pathways leading to programmed cell death (PCD). By using BY-2 tobacco cells, it was shown that both NaCl- and sorbitol-induced PCD seemed to be dependent on superoxide anion (O2·(-)) generation by NADPH-oxidase. In the case of NaCl, an early influx of sodium through non-selective cation channels participates in the development of PCD through mitochondrial dysfunction and NADPH-oxidase-dependent O2·(-) generation. This supports the hypothesis of different pathways in NaCl- and sorbitol-induced cell death. Surprisingly, other shared early responses, such as [Ca(2+)]cyt increase and singlet oxygen production, do not seem to be involved in PCD.

  7. Chaperone-Targeting Cytotoxin and Endoplasmic Reticulum Stress-Inducing Drug Synergize to Kill Cancer Cells

    Directory of Open Access Journals (Sweden)

    Joseph M. Backer

    2009-11-01

    Full Text Available Diverse physiological and therapeutic insults that increase the amount of unfolded or misfolded proteins in the endoplasmic reticulum (ER induce the unfolded protein response, an evolutionarily conserved protective mechanism that manages ER stress. Glucose-regulated protein 78/immunoglobulin heavy-chain binding protein (GRP78/BiP is an ER-resident protein that plays a central role in the ER stress response and is the only known substrate of the proteolytic A subunit (SubA of a novel bacterial AB5 toxin. Here, we report that an engineered fusion protein, epidermal growth factor (EGF-SubA, combining EGF and SubA, is highly toxic to growing and confluent epidermal growth factor receptor-expressing cancer cells, and its cytotoxicity is mediated by a remarkably rapid cleavage of GRP78/BiP. Systemic delivery of EGF-SubA results in a significant inhibition of human breast and prostate tumor xenografts in mouse models. Furthermore, EGF-SubA dramatically increases the sensitivity of cancer cells to the ER stress-inducing drug thapsigargin, and vice versa, demonstrating the first example of mechanism-based synergism in the action of a cytotoxin and an ER-targeting drug.

  8. Involvement of endoplasmic reticulum stress in albuminuria induced inflammasome activation in renal proximal tubular cells.

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    Li Fang

    Full Text Available Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E. Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria.

  9. Epoetin Delta Reduces Oxidative Stress in Primary Human Renal Tubular Cells

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    Annelies De Beuf

    2010-01-01

    Full Text Available Erythropoietin (EPO exerts (renal tissue protective effects. Since it is unclear whether this is a direct effect of EPO on the kidney or not, we investigated whether EPO is able to protect human renal tubular epithelial cells (hTECs from oxidative stress and if so which pathways are involved. EPO (epoetin delta could protect hTECs against oxidative stress by a dose-dependent inhibition of reactive oxygen species formation. This protective effect is possibly related to the membranous expression of the EPO receptor (EPOR since our data point to the membranous EPOR expression as a prerequisite for this protective effect. Oxidative stress reduction went along with the upregulation of renoprotective genes. Whilst three of these, heme oxygenase-1 (HO-1, aquaporin-1 (AQP-1, and B-cell CLL/lymphoma 2 (Bcl-2 have already been associated with EPO-induced renoprotection, this study for the first time suggests carboxypeptidase M (CPM, dipeptidyl peptidase IV (DPPIV, and cytoglobin (Cygb to play a role in this process.

  10. Origins and consequences of hyperosmolar stress in retinal pigmented epithelial cells.

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    Willermain, François; Libert, Sarah; Motulsky, Elie; Salik, Dany; Caspers, Laure; Perret, Jason; Delporte, Christine

    2014-01-01

    The retinal pigmented epithelium (RPE) is composed of retinal pigmented epithelial cells joined by tight junctions and represents the outer blood-retinal barrier (BRB). The inner BRB is made of endothelial cells joined by tight junctions and glial extensions surrounding all the retinal blood vessels. One of the functions of the RPE is to maintain an osmotic transepithelial gradient created by ionic pumps and channels, avoiding paracellular flux. Under such physiological conditions, transcellular water movement follows the osmotic gradient and flows normally from the retina to the choroid through the RPE. Several diseases, such as diabetic retinopathy, are characterized by the BRB breakdown leading to leakage of solutes, proteins, and fluid from the retina and the choroid. The prevailing hypothesis explaining macular edema formation during diabetic retinopathy incriminates the inner BRB breakdown resulting in increased osmotic pressure leading in turn to massive water accumulation that can affect vision. Under these conditions, it has been hypothesized that RPE is likely to be exposed to hyperosmolar stress at its apical side. This review summarizes the origins and consequences of osmotic stress in the RPE. Ongoing and further research advances will clarify the mechanisms, at the molecular level, involved in the response of the RPE to osmotic stress and delineate potential novel therapeutic targets and tools.

  11. Is Liver Enzyme Release Really Associated with Cell Necrosis Induced by Oxidant Stress?

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    Martha Lucinda Contreras-Zentella

    2016-01-01

    Full Text Available Hepatic diseases are a major concern worldwide. Increased specific plasma enzyme activities are considered diagnostic features for liver diseases, since enzymes are released into the blood compartment following the deterioration of the organ. Release of liver mitochondrial enzymes is considered strong evidence for hepatic necrosis, which is associated with an increased production of ROS, often leading to greater hepatic lipid peroxidation. Lipotoxic mediators and intracellular signals activated Kupffer cells, which provides evidence strongly suggesting the participation of oxidant stress in acute liver damage, inducing the progression of liver injury to chronic liver damage. Elevated transaminase activities are considered as an index marker of hepatotoxicity, linked to oxidant stress. However, a drastic increase of serum activities of liver enzyme markers ought not necessarily to reflect liver cell death. In fact, increased serum levels of cytoplasmic enzymes have readily been observed after partial hepatectomy (PH in the regenerating liver of rats. In this regard, we are now showing that in vitro modifications of the oxidant status affect differentially the release of liver enzymes, indicating that this release is a strictly controlled event and not directly related to the onset of oxidant stress of the liver.

  12. Is Liver Enzyme Release Really Associated with Cell Necrosis Induced by Oxidant Stress?

    Science.gov (United States)

    Contreras-Zentella, Martha Lucinda; Hernández-Muñoz, Rolando

    2016-01-01

    Hepatic diseases are a major concern worldwide. Increased specific plasma enzyme activities are considered diagnostic features for liver diseases, since enzymes are released into the blood compartment following the deterioration of the organ. Release of liver mitochondrial enzymes is considered strong evidence for hepatic necrosis, which is associated with an increased production of ROS, often leading to greater hepatic lipid peroxidation. Lipotoxic mediators and intracellular signals activated Kupffer cells, which provides evidence strongly suggesting the participation of oxidant stress in acute liver damage, inducing the progression of liver injury to chronic liver damage. Elevated transaminase activities are considered as an index marker of hepatotoxicity, linked to oxidant stress. However, a drastic increase of serum activities of liver enzyme markers ought not necessarily to reflect liver cell death. In fact, increased serum levels of cytoplasmic enzymes have readily been observed after partial hepatectomy (PH) in the regenerating liver of rats. In this regard, we are now showing that in vitro modifications of the oxidant status affect differentially the release of liver enzymes, indicating that this release is a strictly controlled event and not directly related to the onset of oxidant stress of the liver.

  13. Cell-specific oxidative stress and cytotoxicity after wildfire coarse particulate matter instillation into mouse lung

    International Nuclear Information System (INIS)

    Our previous work has shown that coarse particulate matter (PM10-2.5) from wildfire smoke is more toxic to lung macrophages on an equal dose (by mass) basis than coarse PM isolated from normal ambient air, as evidenced by decreased numbers of macrophages in lung lavage fluid 6 and 24 hours after PM instillation into mouse lungs in vivo and by cytotoxicity to a macrophage cell line observed directly in vitro. We hypothesized that pulmonary macrophages from mice instilled with wildfire coarse PM would undergo more cytotoxicity than macrophages from controls, and that there would be an increase in oxidative stress in their lungs. Cytotoxicity was quantified as decreased viable macrophages and increased percentages of dead macrophages in the bronchoalveolar lavage fluid (BALF) of mice instilled with wildfire coarse PM. At 1 hour after PM instillation, we observed both decreased numbers of viable macrophages and increased dead macrophage percentages as compared to controls. An increase in free isoprostanes, an indicator of oxidative stress, from control values of 28.1 ± 3.2 pg/mL to 83.9 ± 12.2 pg/mL was observed a half-hour after PM instillation. By 1 hour after PM instillation, isoprostane values had returned to 30.4 ± 7.6 pg/mL, not significantly different from control concentrations. Lung sections from mice instilled with wildfire coarse PM showed rapid Clara cell responses,