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Sample records for mediates induced indirect

  1. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants.

    PubMed

    Mutyambai, Daniel M; Bruce, Toby J A; van den Berg, Johnnie; Midega, Charles A O; Pickett, John A; Khan, Zeyaur R

    2016-01-01

    Attack of plants by herbivorous arthropods may result in considerable changes to the plant's chemical phenotype with respect to emission of herbivore-induced plant volatiles (HIPVs). These HIPVs have been shown to act as repellents to the attacking insects as well as attractants for the insects antagonistic to these herbivores. Plants can also respond to HIPV signals from other plants that warn them of impending attack. Recent investigations have shown that certain maize varieties are able to emit volatiles following stemborer egg deposition. These volatiles attract the herbivore's parasitoids and directly deter further oviposition. However, it was not known whether these oviposition-induced maize (Zea mays, L.) volatiles can mediate chemical phenotypic changes in neighbouring unattacked maize plants. Therefore, this study sought to investigate the effect of oviposition-induced maize volatiles on intact neighbouring maize plants in 'Nyamula', a landrace known to respond to oviposition, and a standard commercial hybrid, HB515, that did not. Headspace volatile samples were collected from maize plants exposed to Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) egg deposition and unoviposited neighbouring plants as well as from control plants kept away from the volatile emitting ones. Behavioural bioassays were carried out in a four-arm olfactometer using egg (Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)) and larval (Cotesia sesamiae Cameron (Hymenoptera: Braconidae)) parasitoids. Coupled Gas Chromatography-Mass Spectrometry (GC-MS) was used for volatile analysis. For the 'Nyamula' landrace, GC-MS analysis revealed HIPV production not only in the oviposited plants but also in neighbouring plants not exposed to insect eggs. Higher amounts of EAG-active biogenic volatiles such as (E)-4,8-dimethyl-1,3,7-nonatriene were emitted from these plants compared to control plants. Subsequent behavioural assays with female T. bournieri and C

  2. An Indirect Defence Trait Mediated through Egg-Induced Maize Volatiles from Neighbouring Plants

    PubMed Central

    Mutyambai, Daniel M.; Bruce, Toby J. A.; van den Berg, Johnnie; Midega, Charles A. O.; Pickett, John A.; Khan, Zeyaur R.

    2016-01-01

    Attack of plants by herbivorous arthropods may result in considerable changes to the plant’s chemical phenotype with respect to emission of herbivore-induced plant volatiles (HIPVs). These HIPVs have been shown to act as repellents to the attacking insects as well as attractants for the insects antagonistic to these herbivores. Plants can also respond to HIPV signals from other plants that warn them of impending attack. Recent investigations have shown that certain maize varieties are able to emit volatiles following stemborer egg deposition. These volatiles attract the herbivore’s parasitoids and directly deter further oviposition. However, it was not known whether these oviposition-induced maize (Zea mays, L.) volatiles can mediate chemical phenotypic changes in neighbouring unattacked maize plants. Therefore, this study sought to investigate the effect of oviposition-induced maize volatiles on intact neighbouring maize plants in ‘Nyamula’, a landrace known to respond to oviposition, and a standard commercial hybrid, HB515, that did not. Headspace volatile samples were collected from maize plants exposed to Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) egg deposition and unoviposited neighbouring plants as well as from control plants kept away from the volatile emitting ones. Behavioural bioassays were carried out in a four-arm olfactometer using egg (Trichogramma bournieri Pintureau & Babault (Hymenoptera: Trichogrammatidae)) and larval (Cotesia sesamiae Cameron (Hymenoptera: Braconidae)) parasitoids. Coupled Gas Chromatography-Mass Spectrometry (GC-MS) was used for volatile analysis. For the ‘Nyamula’ landrace, GC-MS analysis revealed HIPV production not only in the oviposited plants but also in neighbouring plants not exposed to insect eggs. Higher amounts of EAG-active biogenic volatiles such as (E)-4,8-dimethyl-1,3,7-nonatriene were emitted from these plants compared to control plants. Subsequent behavioural assays with female T. bournieri

  3. Sensitivity analysis for direct and indirect effects in the presence of exposure-induced mediator-outcome confounders

    PubMed Central

    Chiba, Yasutaka

    2014-01-01

    Questions of mediation are often of interest in reasoning about mechanisms, and methods have been developed to address these questions. However, these methods make strong assumptions about the absence of confounding. Even if exposure is randomized, there may be mediator-outcome confounding variables. Inference about direct and indirect effects is particularly challenging if these mediator-outcome confounders are affected by the exposure because in this case these effects are not identified irrespective of whether data is available on these exposure-induced mediator-outcome confounders. In this paper, we provide a sensitivity analysis technique for natural direct and indirect effects that is applicable even if there are mediator-outcome confounders affected by the exposure. We give techniques for both the difference and risk ratio scales and compare the technique to other possible approaches. PMID:25580387

  4. Assessing Mediational Models: Testing and Interval Estimation for Indirect Effects

    ERIC Educational Resources Information Center

    Biesanz, Jeremy C.; Falk, Carl F.; Savalei, Victoria

    2010-01-01

    Theoretical models specifying indirect or mediated effects are common in the social sciences. An indirect effect exists when an independent variable's influence on the dependent variable is mediated through an intervening variable. Classic approaches to assessing such mediational hypotheses (Baron & Kenny, 1986; Sobel, 1982) have in recent years…

  5. Sclerostin inhibition of Wnt-3a-induced C3H10T1/2 cell differentiation is indirect and mediated by bone morphogenetic proteins.

    PubMed

    Winkler, David G; Sutherland, May S Kung; Ojala, Ethan; Turcott, Eileen; Geoghegan, James C; Shpektor, Diana; Skonier, John E; Yu, Changpu; Latham, John A

    2005-01-28

    High bone mass diseases are caused both by activating mutations in the Wnt pathway and by loss of SOST, a bone morphogenetic protein (BMP) antagonist, leading to the activation of BMP signaling. Given the phenotypic similarity between mutations that activate these signaling pathways, it seems likely that BMPs and Wnts operate in parallel or represent components of the same pathway, modulating osteoblast differentiation. In this study, we show that in C3H10T1/2 cells, Wnt-3A and BMP-6 proteins were inducers of osteoblast differentiation, as measured by alkaline phosphatase (ALP) induction. Surprisingly, sclerostin, noggin, and human BMP receptor 1A (BMPR1A)-FC fusion proteins blocked Wnt-3A-induced ALP as well as BMP-6-induced ALP activity. Dkk-1, a Wnt inhibitor, blocked Wnt-induced ALP activity but not BMP-induced ALP activity. Early Wnt-3A signaling as measured by beta-catenin accumulation was not affected by the BMP antagonists but was blocked by Dkk-1. Wnt-3A induced the appearance of BMP-4 mRNA 12 h prior to that of ALP in C3H10T1/2 cells. We propose that sclerostin and other BMP antagonists do not block Wnt signaling directly. Sclerostin blocks Wnt-induced ALP activity by blocking the activity of BMP proteins produced by Wnt treatment. The expression of BMP proteins in this autocrine loop is essential for Wnt-3A-induced osteoblast differentiation. PMID:15545262

  6. In vitro particulate matter exposure causes direct and lung-mediated indirect effects on cardiomyocyte function.

    PubMed

    Gorr, Matthew W; Youtz, Dane J; Eichenseer, Clayton M; Smith, Korbin E; Nelin, Timothy D; Cormet-Boyaka, Estelle; Wold, Loren E

    2015-07-01

    Particulate matter (PM) exposure induces a pathological response from both the lungs and the cardiovascular system. PM is capable of both manifestation into the lung epithelium and entrance into the bloodstream. Therefore, PM has the capacity for both direct and lung-mediated indirect effects on the heart. In the present studies, we exposed isolated rat cardiomyocytes to ultrafine particulate matter (diesel exhaust particles, DEP) and examined their contractile function and calcium handling ability. In another set of experiments, lung epithelial cells (16HBE14o- or Calu-3) were cultured on permeable supports that allowed access to both the basal (serosal) and apical (mucosal) media; the basal media was used to culture cardiomyocytes to model the indirect, lung-mediated effects of PM on the heart. Both the direct and indirect treatments caused a reduction in contractility as evidenced by reduced percent sarcomere shortening and reduced calcium handling ability measured in field-stimulated cardiomyocytes. Treatment of cardiomyocytes with various anti-oxidants before culture with DEP was able to partially prevent the contractile dysfunction. The basal media from lung epithelial cells treated with PM contained several inflammatory cytokines, and we found that monocyte chemotactic protein-1 was a key trigger for cardiomyocyte dysfunction. These results indicate the presence of both direct and indirect effects of PM on cardiomyocyte function in vitro. Future work will focus on elucidating the mechanisms involved in these separate pathways using in vivo models of air pollution exposure. PMID:25957217

  7. Indirect radiative forcing by ion-mediated nucleation of aerosol

    SciTech Connect

    Yu, Fangqun; Luo, Gan; Liu, Xiaohong; Easter, Richard C.; Ma, Xiaoyan; Ghan, Steven J.

    2012-12-03

    A clear understanding of particle formation mechanisms is critical for assessing aerosol indirect radiative forcing and associated climate feedback processes. Recent studies reveal the importance of ion-mediated nucleation (IMN) in generating new particles and cloud condensation nuclei (CCN) in the atmosphere. Here we implement for the first time a physically based treatment of IMN into the Community Atmosphere Model version 5. Our simulations show that, compared to globally averaged results based on binary homogeneous nucleation (BHN), the presence of ionization (i.e., IMN) halves H2SO4 column burden, but increases the column integrated nucleation rate by around one order of magnitude, total particle number burden by a factor of ~ 3, CCN burden by ~ 10% (at 0.2% supersaturation) to 65% (at 1.0% supersaturation), and cloud droplet number burden by ~ 18%. Compared to BHN, IMN increases cloud liquid water path by 7.5%, decreases precipitation by 1.1%, and increases total cloud cover by 1.9%. This leads to an increase of total shortwave cloud radiative forcing by 3.67 W/m2 (more negative) and longwave cloud forcing by 1.78 W/m2 (more positive), resulting in a -1.9 W/m2 net change in cloud radiative forcing associated with IMN. The significant impacts of ionization on global aerosol formation, CCN abundance, and cloud radiative forcing may provide an important physical mechanism linking the global energy balance to various processes affecting atmospheric ionization, which should be properly represented in climate models.

  8. Biphasic effects of direct, but not indirect, GABA mimetics and antagonists on haloperidol-induced catalepsy.

    PubMed

    Worms, P; Lloyd, K G

    1980-03-01

    At very low doses the GABA agonists SL 76002 and muscimol diminish haloperidol-induced catalepsy. At somewhat higher doses these compounds potentiate catalepsy. Biphasic effects on DA-receptor mediated functions have previously been noted with bicuculline and picrotoxinin. In contrast, manipulation of GABA levels by enzyme inhibition induced only a monophasic effect on dopamine-mediated behaviour. The potentiation of GABA levels by enzyme inhibition induced only a monophasic effect on dopamine-mediated behaviour. The potentiation of haloperidol-induced catalepsy by GABA mimetics is also observed with dipropylacetate, delta-aminovaleric acid and gamma-acetylenic GABA. This GABA-mimetic potentiation of catakepsy was blocked by the coadministration of bicuculline. These results confirm and extend the hypothesis that GABA-neurons influence DA neuron function. Furthermore they suggest that more than one group of GABA receptors influence directly and/or indirectly DA neuronal function, with different resultant effects. PMID:7189827

  9. Quantifying and Testing Indirect Effects in Simple Mediation Models when the Constituent Paths Are Nonlinear

    ERIC Educational Resources Information Center

    Hayes, Andrew F.; Preacher, Kristopher J.

    2010-01-01

    Most treatments of indirect effects and mediation in the statistical methods literature and the corresponding methods used by behavioral scientists have assumed linear relationships between variables in the causal system. Here we describe and extend a method first introduced by Stolzenberg (1980) for estimating indirect effects in models of…

  10. Hidden risks and benefits of natural enemy-mediated indirect effects.

    PubMed

    Kaser, Joe M; Ode, Paul J

    2016-04-01

    Polyphagous natural enemies can mediate a variety of indirect interactions between resource populations. Such indirect interactions are often reciprocally negative (i.e. apparent competition), but the sign of effects between resource populations can be any combination of positive (+), negative (-), or neutral (0). In this article we focus on parasitoids to illustrate the importance of natural enemy-mediated indirect interactions in predicting risk and efficacy in biological control. We review recent findings to illustrate how an improved understanding of parasitoid behavioral ecology may increase model accuracy. PMID:27436655

  11. Proton-induced direct and indirect damage of plasmid DNA.

    PubMed

    Vyšín, Luděk; Pachnerová Brabcová, Kateřina; Štěpán, Václav; Moretto-Capelle, Patrick; Bugler, Beatrix; Legube, Gaelle; Cafarelli, Pierre; Casta, Romain; Champeaux, Jean Philippe; Sence, Martine; Vlk, Martin; Wagner, Richard; Štursa, Jan; Zach, Václav; Incerti, Sebastien; Juha, Libor; Davídková, Marie

    2015-08-01

    Clustered DNA damage induced by 10, 20 and 30 MeV protons in pBR322 plasmid DNA was investigated. Besides determination of strand breaks, additional lesions were detected using base excision repair enzymes. The plasmid was irradiated in dry form, where indirect radiation effects were almost fully suppressed, and in water solution containing only minimal residual radical scavenger. Simultaneous irradiation of the plasmid DNA in the dry form and in the solution demonstrated the contribution of the indirect effect as prevalent. The damage composition slightly differed when comparing the results for liquid and dry samples. The obtained data were also subjected to analysis concerning different methodological approaches, particularly the influence of irradiation geometry, models used for calculation of strand break yields and interpretation of the strand breaks detected with the enzymes. It was shown that these parameters strongly affect the results. PMID:26007308

  12. Habitat effects on the relative importance of trait- and density-mediated indirect interactions.

    PubMed

    Trussell, Geoffrey C; Ewanchuk, Patrick J; Matassa, Catherine M

    2006-11-01

    Classical views of trophic cascades emphasize the primacy of consumptive predator effects on prey populations to the transmission of indirect effects [density-mediated indirect interactions (DMIIs)]. However, trophic cascades can also emerge without changes in the density of interacting species because of non-consumptive predator effects on prey traits such as foraging behaviour [trait-mediated indirect interactions (TMIIs)]. Although ecologists appreciate this point, measurements of the relative importance of each indirect predator effect are rare. Experiments with a three-level, rocky shore food chain containing an invasive predatory crab (Carcinus maenas), an intermediate consumer (the snail, Nucella lapillus) and a basal resource (the barnacle, Semibalanus balanoides) revealed that the strength of TMIIs is comparable with, or exceeds, that of DMIIs. Moreover, the sign and strength of each indirect predator effect depends on whether it is measured in risky or refuge habitats. Because habitat shifts are often responsible for the emergence of TMIIs, attention to the sign and strength of these interactions in both habitats will improve our understanding of the link between individual behaviour and community dynamics. PMID:17040327

  13. Dimethyl Sulfoxide Induces Both Direct and Indirect Tau Hyperphosphorylation

    PubMed Central

    Julien, Carl; Marcouiller, François; Bretteville, Alexis; El Khoury, Noura B.; Baillargeon, Joanie; Hébert, Sébastien S.; Planel, Emmanuel

    2012-01-01

    Dimethyl sulfoxide (DMSO) is widely used as a solvent or vehicle for biological studies, and for treatment of specific disorders, including traumatic brain injury and several forms of amyloidosis. As Alzheimer’s disease (AD) brains are characterized by deposits of β-amyloid peptides, it has been suggested that DMSO could be used as a treatment for this devastating disease. AD brains are also characterized by aggregates of hyperphosphorylated tau protein, but the effect of DMSO on tau phosphorylation is unknown. We thus investigated the impact of DMSO on tau phosphorylation in vitro and in vivo. One hour following intraperitoneal administration of 1 or 2 ml/kg DMSO in mice, no change was observed in tau phosphorylation. However, at 4 ml/kg, tau was hyperphosphorylated at AT8 (Ser202/Thr205), PHF-1 (Ser396/Ser404) and AT180 (Thr231) epitopes. At this dose, we also noticed that the animals were hypothermic. When the mice were maintained normothermic, the effect of 4 ml/kg DMSO on tau hyperphosphorylation was prevented. On the other hand, in SH-SY5Y cells, 0.1% DMSO induced tau hyperphosphorylation at AT8 and AT180 phosphoepitopes in normothermic conditions. Globally, these findings demonstrate that DMSO can induce tau hyperphosphorylation indirectly via hypothermia in vivo, and directly in vitro. These data should caution researchers working with DMSO as it can induce artifactual results both in vivo and in vitro. PMID:22768202

  14. Asymmetric competition via induced resistance: specialist herbivores indirectly suppress generalist preference and populations.

    PubMed

    Long, Jeremy D; Hamilton, Rebecca S; Mitchell, Jocelyn L

    2007-05-01

    Species may compete indirectly by altering the traits of a shared resource. For example, herbivore-induced responses in plants may make plants more resistant or susceptible to additional herbivorous insect species. Herbivore-induced plant responses can significantly affect interspecific competition and herbivore population dynamics. These herbivore-herbivore indirect interactions have been overlooked in aquatic ecosystems where previous studies used the same herbivore species to induce changes and to assess the effects of these changes. We asked whether seaweed grazing by one of two herbivorous, congeneric snail species (Littorina obtusata or Littorina littorea) with different feeding strategies and preferences would affect subsequent feeding preferences of three herbivore species (both snails and the isopod Idotea baltica) and population densities of three herbivore species (both snails and a third periwinkle snail, Lacuna vincta). In addition, we measured phlorotannin concentrations to test the hypothesis that these metabolites function as induced defenses in the Phaeophyceae. Snail herbivory induced cue-specific responses in apical tissues of the seaweed Fucus vesiculosus that affected the three herbivore species similarly. When compared to ungrazed controls, direct grazing by Littorina obtusata reduced seaweed palatability by at least 52% for both snail species and the isopod species. In contrast, direct grazing by L. littorea did not decrease seaweed palatability for any herbivore, indicating herbivore-specific responses. Previous grazing by L. obtusata reduced populations of L. littorea on outplanted seaweeds by 46% but had no effect on L. obtusata populations. Phlorotannins, a potential class of inducible chemicals in brown algae, were not more concentrated in grazed seaweed tissues, suggesting that some other trait was responsible for the induced resistance. Our results indicate that marine herbivores may compete via inducible responses in shared seaweeds

  15. Aptamer-mediated indirect quantum dot labeling and fluorescent imaging of target proteins in living cells

    NASA Astrophysics Data System (ADS)

    Liu, Jianbo; Zhang, Pengfei; Yang, Xiaohai; Wang, Kemin; Guo, Qiuping; Huang, Jin; Li, Wei

    2014-12-01

    Protein labeling for dynamic living cell imaging plays a significant role in basic biological research, as well as in clinical diagnostics and therapeutics. We have developed a novel strategy in which the dynamic visualization of proteins within living cells is achieved by using aptamers as mediators for indirect protein labeling of quantum dots (QDs). With this strategy, the target protein angiogenin was successfully labeled with fluorescent QDs in a minor intactness model, which was mediated by the aptamer AL6-B. Subsequent living cell imaging analyses indicated that the QDs nanoprobes were selectively bound to human umbilical vein endothelial cells, gradually internalized into the cytoplasm, and mostly localized in the lysosome organelle, indicating that the labeled protein retained high activity. Compared with traditional direct protein labeling methods, the proposed aptamer-mediated strategy is simple, inexpensive, and provides a highly selective, stable, and intact labeling platform that has shown great promise for future biomedical labeling and intracellular protein dynamic analyses.

  16. Epibiotic mutualists alter coral susceptibility and response to biotic disturbance through cascading trait-mediated indirect interactions

    NASA Astrophysics Data System (ADS)

    Bergsma, G. S.

    2012-06-01

    Biotic disturbances are important drivers of community structure, but interactions among community members can determine trajectories of response and recovery. On coral reefs in French Polynesia, epibiotic amphipods induce the formation of branch-like "fingers" on flat colonies of encrusting Montipora coral. The fingers form as coral encrusts the amphipods' tubes and lead to significant changes in colony morphology. I tested whether the induced morphological changes affect Montipora's susceptibility to predation by pincushion ( Culcita novaeguineae) and crown-of-thorns sea stars ( Acanthaster planci). Montipora with fingers were less likely to be attacked and more likely to survive attack than colonies without fingers. Furthermore, the presence of fingers altered A. planci prey preference. Sea stars preferred Montipora without fingers over other common coral genera, but preferred other genera when Montipora had fingers. Amphipods indirectly affected Montipora's resistance and resilience to predation, and the susceptibility of other coral genera to predation, through induced morphological changes. Such trait-mediated indirect interactions likely play an important role in determining how species respond to periodic sea star outbreaks.

  17. 27 CFR 6.42 - Indirect inducement through third party arrangements.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Indirect inducement through third party arrangements. 6.42 Section 6.42 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Furnishing Things of Value § 6.42 Indirect...

  18. 27 CFR 6.42 - Indirect inducement through third party arrangements.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Indirect inducement through third party arrangements. 6.42 Section 6.42 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Furnishing Things of Value § 6.42 Indirect...

  19. 27 CFR 6.42 - Indirect inducement through third party arrangements.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Indirect inducement through third party arrangements. 6.42 Section 6.42 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Furnishing Things of Value § 6.42 Indirect...

  20. Direct Arylation of Pyrroles via Indirect Electroreductive C-H Functionalization Using Perylene Bisimide as an Electron-Transfer Mediator.

    PubMed

    Sun, Guoquan; Ren, Shuya; Zhu, Xinhai; Huang, Manna; Wan, Yiqian

    2016-02-01

    The indirect electroreductive coupling of aryl halides and pyrroles was successfully conducted using a catalytic amount of perylene bisimide as a mediator in 1-ethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([EMIM]NTf2)/DMSO. PMID:26800089

  1. Estimation of Indirect Effects in the Presence of Unmeasured Confounding for the Mediator-Outcome Relationship in a Multilevel 2-1-1 Mediation Model

    ERIC Educational Resources Information Center

    Talloen, Wouter; Moerkerke, Beatrijs; Loeys, Tom; De Naeghel, Jessie; Van Keer, Hilde; Vansteelandt, Stijn

    2016-01-01

    To assess the direct and indirect effect of an intervention, multilevel 2-1-1 studies with intervention randomized at the upper (class) level and mediator and outcome measured at the lower (student) level are frequently used in educational research. In such studies, the mediation process may flow through the student-level mediator (the within…

  2. Plant genetic variation mediates an indirect ecological effect between belowground earthworms and aboveground aphids

    PubMed Central

    2014-01-01

    Background Interactions between aboveground and belowground terrestrial communities are often mediated by plants, with soil organisms interacting via the roots and aboveground organisms via the shoots and leaves. Many studies now show that plant genetics can drive changes in the structure of both above and belowground communities; however, the role of plant genetic variation in mediating aboveground-belowground interactions is still unclear. We used an earthworm-plant-aphid model system with two aphid species (Aphis fabae and Acyrthosiphon pisum) to test the effect of host-plant (Vicia faba) genetic variation on the indirect interaction between the belowground earthworms (Eisenia veneta) on the aboveground aphid populations. Results Our data shows that host-plant variety mediated an indirect ecological effect of earthworms on generalist black bean aphids (A. fabae), with earthworms increasing aphid growth rate in three plant varieties but decreasing it in another variety. We found no effect of earthworms on the second aphid species, the pea aphid (A. pisum), and no effect of competition between the aphid species. Plant biomass was increased when earthworms were present, and decreased when A. pisum was feeding on the plant (mediated by plant variety). Although A. fabae aphids were influenced by the plants and worms, they did not, in turn, alter plant biomass. Conclusions Previous work has shown inconsistent effects of earthworms on aphids, but we suggest these differences could be explained by plant genetic variation and variation among aphid species. This study demonstrates that the outcome of belowground-aboveground interactions can be mediated by genetic variation in the host-plant, but depends on the identity of the species involved. PMID:25331082

  3. Salinity and disturbance mediate direct and indirect plant-plant interactions in an assembled marsh community.

    PubMed

    Wang, Cheng-Huan; Li, Bo

    2016-09-01

    Direct and indirect plant-plant interactions play important roles in structuring plant communities, but the relative importance of physical stress and biological disturbance in mediating competitive outcomes remains debated. We conducted two common garden experiments to examine the influence of salinity and disturbance (sediment accretion and clipping) on competitive interactions among three native sedges (Scirpus mariqueter, Scirpus triqueter, and Carex scabrifolia) in the Yangtze estuary. In both experiments, the relative competitive abilities of these plants shifted among different treatments. Competition importance rather than intensity significantly decreased with increasing stress. At the community level, competition importance showed reduced variation along the stress gradient in the disturbance experiment. Notably, the performance of these sedges in three-species mixtures could not be predicted by their competitive relationships in two-species mixtures, which was an indication of indirect interactions. Salinity, disturbance and indirect interactions all affected the competitive dynamics of these sedges, which could explain their different performances and natural distributions in the Yangtze estuary. Our findings of the complex effects of physical factors and multi-species interactions, as well as the different patterns of competition importance along stress gradients at the species level and the community level can improve our understanding of plant community organization in salt marshes and other ecosystems with sharp environmental gradients. PMID:27164913

  4. Susceptibility to predation affects trait-mediated indirect interactions by reversing interspecific competition.

    PubMed

    Mowles, Sophie L; Rundle, Simon D; Cotton, Peter A

    2011-01-01

    Numerous studies indicate that the behavioral responses of prey to the presence of predators can have an important role in structuring assemblages through trait-mediated indirect interactions. Few studies, however, have addressed how relative susceptibility to predation influences such interactions. Here we examine the effect of chemical cues from the common shore crab Carcinus maenas on the foraging behavior of two common intertidal gastropod molluscs. Of the two model consumers studied, Littorina littorea is morphologically more vulnerable to crab predation than Gibbula umbilicalis, and it exhibited greater competitive ability in the absence of predation threat. However, Littorina demonstrated a greater anti-predator response when experimentally exposed to predation cues, resulting in a lower level of foraging. This reversed the competitive interaction, allowing Gibbula substantially increased access to shared resources. Our results demonstrate that the susceptibility of consumers to predation can influence species interactions, and suggest that inter-specific differences in trait-mediated indirect interactions are another mechanism through which non-consumptive predator effects may influence trophic interactions. PMID:21857993

  5. Susceptibility to Predation Affects Trait-Mediated Indirect Interactions by Reversing Interspecific Competition

    PubMed Central

    Mowles, Sophie L.; Rundle, Simon D.; Cotton, Peter A.

    2011-01-01

    Numerous studies indicate that the behavioral responses of prey to the presence of predators can have an important role in structuring assemblages through trait-mediated indirect interactions. Few studies, however, have addressed how relative susceptibility to predation influences such interactions. Here we examine the effect of chemical cues from the common shore crab Carcinus maenas on the foraging behavior of two common intertidal gastropod molluscs. Of the two model consumers studied, Littorina littorea is morphologically more vulnerable to crab predation than Gibbula umbilicalis, and it exhibited greater competitive ability in the absence of predation threat. However, Littorina demonstrated a greater anti-predator response when experimentally exposed to predation cues, resulting in a lower level of foraging. This reversed the competitive interaction, allowing Gibbula substantially increased access to shared resources. Our results demonstrate that the susceptibility of consumers to predation can influence species interactions, and suggest that inter-specific differences in trait-mediated indirect interactions are another mechanism through which non-consumptive predator effects may influence trophic interactions. PMID:21857993

  6. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edwards; Kuhr, Werner G.

    1991-04-09

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  7. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOEpatents

    Yeung, Edward S.; Kuhr, Werner G.

    1996-02-20

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  8. Resource-Mediated Indirect Effects of Grassland Management on Arthropod Diversity

    PubMed Central

    Simons, Nadja K.; Gossner, Martin M.; Lewinsohn, Thomas M.; Boch, Steffen; Lange, Markus; Müller, Jörg; Pašalić, Esther; Socher, Stephanie A.; Türke, Manfred; Fischer, Markus; Weisser, Wolfgang W.

    2014-01-01

    Intensive land use is a driving force for biodiversity decline in many ecosystems. In semi-natural grasslands, land-use activities such as mowing, grazing and fertilization affect the diversity of plants and arthropods, but the combined effects of different drivers and the chain of effects are largely unknown. In this study we used structural equation modelling to analyse how the arthropod communities in managed grasslands respond to land use and whether these responses are mediated through changes in resource diversity or resource quantity (biomass). Plants were considered resources for herbivores which themselves were considered resources for predators. Plant and arthropod (herbivores and predators) communities were sampled on 141 meadows, pastures and mown pastures within three regions in Germany in 2008 and 2009. Increasing land-use intensity generally increased plant biomass and decreased plant diversity, mainly through increasing fertilization. Herbivore diversity decreased together with plant diversity but showed no response to changes in plant biomass. Hence, land-use effects on herbivore diversity were mediated through resource diversity rather than quantity. Land-use effects on predator diversity were mediated by both herbivore diversity (resource diversity) and herbivore quantity (herbivore biomass), but indirect effects through resource quantity were stronger. Our findings highlight the importance of assessing both direct and indirect effects of land-use intensity and mode on different trophic levels. In addition to the overall effects, there were subtle differences between the different regions, pointing to the importance of regional land-use specificities. Our study underlines the commonly observed strong effect of grassland land use on biodiversity. It also highlights that mechanistic approaches help us to understand how different land-use modes affect biodiversity. PMID:25188423

  9. Bottom-up and top-down mechanisms indirectly mediate interactions between benthic biotic ecosystem components

    NASA Astrophysics Data System (ADS)

    Van Colen, Carl; Thrush, Simon F.; Parkes, Samantha; Harris, Rachel; Woodin, Sally A.; Wethey, David S.; Pilditch, Conrad A.; Hewitt, Judi E.; Lohrer, Andrew M.; Vincx, Magda

    2015-04-01

    The loss or decline in population size of key species can instigate a cascade of effects that have implications for interacting species, therewith impacting biodiversity and ecosystem functioning. We examined how top-down and bottom-up interactions may mediate knock-on effects of a coastal deposit-feeding clam, Macomona liliana (hereafter Macomona), on sandflat meiobenthos densities. Therefore we manipulated densities of Macomona in combination with predator exclusion and experimental shading that was expected to alter microphytobenthos biomass. We show that Macomona regulated densities of meiobenthic (38-500 μm) nematodes, copepods, polychaetes, turbellarians, and ostracodes during the three months of incubation via indirect mechanisms. Predator pressure on Macomona by eagle rays (Myliobatis tenuicaudatus) was found to have a negative effect on densities of some meiobenthic taxa. Furthermore, experimental shading resulted in the loss of a positive relation between Macomona and microphytobenthos biomass, while concurrently increasing the density of some meiobenthic taxa. We suggest that this observation can be explained by the release from bioturbation interference effects of the cockle Austrovenus stutchburyi that was found to thrive in the presence of Macomona under non-shaded conditions. Our results highlight the importance of interactions between macrofaunal bioturbation, microphyte biomass, sediment stability, and predation pressure for the structuring of benthic communities. This experiment illustrates that manipulative field experiments may be particularly suitable to study such multiple indirect mechanisms that regulate ecosystem diversity and related functioning because such approaches may best capture the complex feedbacks and processes that determine ecosystem dynamics.

  10. Notch signaling enhances FcεRI-mediated cytokine production by mast cells through direct and indirect mechanisms.

    PubMed

    Nakano, Nobuhiro; Nishiyama, Chiharu; Yagita, Hideo; Hara, Mutsuko; Motomura, Yasutaka; Kubo, Masato; Okumura, Ko; Ogawa, Hideoki

    2015-05-01

    Th2-type cytokines and TNF-α secreted by activated mast cells upon cross-linking of FcεRI contribute to the development and maintenance of Th2 immunity to parasites and allergens. We have previously shown that cytokine secretion by mouse mast cells is enhanced by signaling through Notch receptors. In this study, we investigated the molecular mechanisms by which Notch signaling enhances mast cell cytokine production induced by FcεRI cross-linking. FcεRI-mediated production of cytokines, particularly IL-4, was significantly enhanced in mouse bone marrow-derived mast cells by priming with Notch ligands. Western blot analysis showed that Notch signaling augmented and prolonged FcεRI-mediated phosphorylation of MAPKs, mainly JNK and p38 MAPK, through suppression of the expression of SHIP-1, a master negative regulator of FcεRI signaling, resulting in the enhanced production of multiple cytokines. The enhancing effect of Notch ligand priming on multiple cytokine production was abolished by knockdown of Notch2, but not Notch1, and FcεRI-mediated production of multiple cytokines was enhanced by retroviral transduction with the intracellular domain of Notch2. However, only IL-4 production was enhanced by both Notch1 and Notch2. The enhancing effect of Notch signaling on IL-4 production was lost in bone marrow-derived mast cells from mice lacking conserved noncoding sequence 2, which is located at the distal 3' element of the Il4 gene locus and contains Notch effector RBP-J binding sites. These results indicate that Notch2 signaling indirectly enhances the FcεRI-mediated production of multiple cytokines, and both Notch1 and Notch2 signaling directly enhances IL-4 production through the noncoding sequence 2 enhancer of the Il4 gene. PMID:25821223

  11. Predator crypsis enhances behaviourally mediated indirect effects on plants by altering bumblebee foraging preferences

    PubMed Central

    Ings, Thomas C.; Chittka, Lars

    2009-01-01

    Predators of pollinators can influence pollination services and plant fitness via both consumptive (reducing pollinator density) and non-consumptive (altering pollinator behaviour) effects. However, a better knowledge of the mechanisms underlying behaviourally mediated indirect effects of predators is necessary to properly understand their role in community dynamics. We used the tripartite relationship between bumblebees, predatory crab spiders and flowers to ask whether behaviourally mediated effects are localized to flowers harbouring predators, or whether bees extend their avoidance to entire plant species. In a tightly controlled laboratory environment, bumblebees (Bombus terrestris) were exposed to a random mixture of equally rewarding yellow and white artificial flowers, but foraging on yellow flowers was very risky: bees had a 25 per cent chance of receiving a simulated predation attempt by ‘robotic’ crab spiders. As bees learnt to avoid ‘dangerous’ flowers, their foraging preferences changed and they began to visit fewer yellow flowers than expected by chance. Bees avoided spider-free yellow flowers as well as dangerous yellow flowers when spiders were more difficult to detect (the colour of yellow spiders was indistinguishable from that of yellow flowers). Therefore, this interaction between bee learning and predator crypsis could lead flower species harbouring cryptic predators to suffer from reduced reproductive success. PMID:19324797

  12. Epichloë Endophytes Alter Inducible Indirect Defences in Host Grasses

    PubMed Central

    Li, Tao; Blande, James D.; Gundel, Pedro E.; Helander, Marjo; Saikkonen, Kari

    2014-01-01

    Epichloë endophytes are common symbionts living asymptomatically in pooid grasses and may provide chemical defences against herbivorous insects. While the mechanisms underlying these fungal defences have been well studied, it remains unknown whether endophyte presence affects the host's own defences. We addressed this issue by examining variation in the impact of Epichloë on constitutive and herbivore-induced emissions of volatile organic compounds (VOC), a well-known indirect plant defence, between two grass species, Schedonorus phoenix (ex. Festuca arundinacea; tall fescue) and Festuca pratensis (meadow fescue). We found that feeding by a generalist aphid species, Rhopalosiphum padi, induced VOC emissions by uninfected plants of both grass species but to varying extents, while mechanical wounding failed to do so in both species after one day of damage. Interestingly, regardless of damage treatment, Epichloë uncinata-infected F. pratensis emitted significantly lower quantities of VOCs than their uninfected counterparts. In contrast, Epichloë coenophiala-infected S. phoenix did not differ from their uninfected counterparts in constitutive VOC emissions but tended to increase VOC emissions under intense aphid feeding. A multivariate analysis showed that endophyte status imposed stronger differences in VOC profiles of F. pratensis than damage treatment, while the reverse was true for S. phoenix. Additionally, both endophytes inhibited R. padi population growth as measured by aphid dry biomass, with the inhibition appearing greater in E. uncinata-infected F. pratensis. Our results suggest, not only that Epichloë endophytes may play important roles in mediating host VOC responses to herbivory, but also that the magnitude and direction of such responses may vary with the identity of the Epichloë–grass symbiosis. Whether Epichloë-mediated host VOC responses will eventually translate into effects on higher trophic levels merits future investigation. PMID:24978701

  13. Conceptualizing and Testing Random Indirect Effects and Moderated Mediation in Multilevel Models: New Procedures and Recommendations

    ERIC Educational Resources Information Center

    Bauer, Daniel J.; Preacher, Kristopher J.; Gil, Karen M.

    2006-01-01

    The authors propose new procedures for evaluating direct, indirect, and total effects in multilevel models when all relevant variables are measured at Level 1 and all effects are random. Formulas are provided for the mean and variance of the indirect and total effects and for the sampling variances of the average indirect and total effects.…

  14. Photobiomodulation Mitigates Diabetes-Induced Retinopathy by Direct and Indirect Mechanisms: Evidence from Intervention Studies in Pigmented Mice

    PubMed Central

    Liu, Haitao; Patel, Shyam; Roberts, Robin; Berkowitz, Bruce A.; Kern, Timothy S.

    2015-01-01

    Objective Daily application of far-red light from the onset of diabetes mitigated diabetes-induced abnormalities in retinas of albino rats. Here, we test the hypothesis that photobiomodulation (PBM) is effective in diabetic, pigmented mice, even when delayed until weeks after onset of diabetes. Direct and indirect effects of PBM on the retina also were studied. Methods Diabetes was induced in C57Bl/6J mice using streptozotocin. Some diabetics were exposed to PBM therapy (4 min/day; 670 nm) daily. In one study, mice were diabetic for 4 weeks before initiation of PBM for an additional 10 weeks. Retinal oxidative stress, inflammation, and retinal function were measured. In some mice, heads were covered with a lead shield during PBM to prevent direct illumination of the eye, or animals were treated with an inhibitor of heme oxygenase-1. In a second study, PBM was initiated immediately after onset of diabetes, and administered daily for 2 months. These mice were examined using manganese-enhanced MRI to assess effects of PBM on transretinal calcium channel function in vivo. Results PBM intervention improved diabetes-induced changes in superoxide generation, leukostasis, expression of ICAM-1, and visual performance. PBM acted in part remotely from the retina because the beneficial effects were achieved even with the head shielded from the light therapy, and because leukocyte-mediated cytotoxicity of retinal endothelial cells was less in diabetics treated with PBM. SnPP+PBM significantly reduced iNOS expression compared to PBM alone, but significantly exacerbated leukostasis. In study 2, PBM largely mitigated diabetes-induced retinal calcium channel dysfunction in all retinal layers. Conclusions PBM induces retinal protection against abnormalities induced by diabetes in pigmented animals, and even as an intervention. Beneficial effects on the retina likely are mediated by both direct and indirect mechanisms. PBM is a novel non-pharmacologic treatment strategy to inhibit

  15. Indirect plant-parasitoid interactions mediated by changes in herbivore physiology.

    PubMed

    Kaplan, Ian; Carrillo, Juli; Garvey, Michael; Ode, Paul J

    2016-04-01

    In occupying an intermediate trophic position, herbivorous insects serve a vital link between plants at the base of the food chain and parasitoids at the top. Although these herbivore-mediated indirect plant-parasitoid interactions are well-documented, new studies have uncovered previously undescribed mechanisms that are fundamentally changing how we view tri-trophic relationships. In this review we highlight recent advances in this field focusing on both plant-driven and parasitoid-driven outcomes that flow up and down the trophic web, respectively. From the bottom-up, plant metabolites can impact parasitoid success by altering host immune function; however, few have considered the potential effects of other plant defense strategies such as tolerance on parasitoid ecology and behavior. From the top-down, parasitoids have long been considered plant bodyguards, but in reality the consequences of parasitism for herbivory rates and induction of plant defensive chemistry are far more complicated with cascading effects on community-level interactions. PMID:27436656

  16. MP-4 Contributes to Snake Venom Neutralization by Mucuna pruriens Seeds through an Indirect Antibody-mediated Mechanism.

    PubMed

    Kumar, Ashish; Gupta, Chitra; Nair, Deepak T; Salunke, Dinakar M

    2016-05-20

    Mortality due to snakebite is a serious public health problem, and available therapeutics are known to induce debilitating side effects. Traditional medicine suggests that seeds of Mucuna pruriens can provide protection against the effects of snakebite. Our aim is to identify the protein(s) that may be important for snake venom neutralization and elucidate its mechanism of action. To this end, we have identified and purified a protein from M. pruriens, which we have named MP-4. The full-length polypeptide sequence of MP-4 was obtained through N-terminal sequencing of peptide fragments. Sequence analysis suggested that the protein may belong to the Kunitz-type protease inhibitor family and therefore may potentially neutralize the proteases present in snake venom. Using various structural and biochemical tools coupled with in vivo assays, we are able to show that MP-4 does not afford direct protection against snake venom because it is actually a poor inhibitor of serine proteases. Further experiments showed that antibodies generated against MP-4 cross-react with the whole venom and provide protection to mice against Echis carinatus snake venom. This study shows that the MP-4 contributes significantly to the snake venom neutralization activity of M. pruriens seeds through an indirect antibody-mediated mechanism. PMID:26987900

  17. Photoheat-induced Schottky nanojunction and indirect Mott transition in VO2: photocurrent analysis

    NASA Astrophysics Data System (ADS)

    Kim, Hyun-Tak; Kim, Minjung; Sohn, Ahrum; Slusar, Tetiana; Seo, Giwan; Cheong, Hyeonsik; Kim, Dong-Wook

    2016-03-01

    In order to elucidate a mechanism of the insulator-to-metal transition (IMT) for a Mott insulator VO2 (3d 1), we present Schottky nanojunctions and the structural phase transition (SPT) by simultaneous nanolevel measurements of photocurrent and Raman scattering in microlevel devices. The Schottky nanojunction with the monoclinic metallic phase between the monoclinic insulating phases is formed by the photoheat-induced IMT not accompanied with the SPT. The temperature dependence of the Schottky junction reveals that the Mott insulator has an electronic structure of an indirect subband between the main Hubbard d bands. The IMT as reverse process of the Mott transition occurs by temperature-induced excitation of bound charges in the indirect semiconductor band, most likely formed by impurities such as oxygen deficiency. The metal band (3d 1) for the Mott insulator is screened (trapped) by the indirect band (impurities).

  18. 27 CFR 6.42 - Indirect inducement through third party arrangements.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... payments for advertising to a retailer association or a display company where the resulting benefits flow... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Indirect inducement through third party arrangements. 6.42 Section 6.42 Alcohol, Tobacco Products and Firearms ALCOHOL...

  19. Mediation analysis to estimate direct and indirect milk losses associated with bacterial load in bovine subclinical mammary infections.

    PubMed

    Detilleux, J; Theron, L; Duprez, J-N; Reding, E; Moula, N; Detilleux, M; Bertozzi, C; Hanzen, C; Mainil, J

    2016-08-01

    Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e. direct losses) or to effects of the immune response triggered by the presence of mammary pathogens (i.e. indirect losses). Test-day milk somatic cell counts (SCC) and number of bacterial colony forming units (CFU) found in milk samples are putative measures of the level of immune response and of the bacterial load, respectively. Mediation models, in which one independent variable affects a second variable which, in turn, affects a third one, are conceivable models to estimate direct and indirect losses. Here, we evaluated the feasibility of a mediation model in which test-day SCC and milk were regressed toward bacterial CFU measured at three selected sampling dates, 1 week apart. We applied this method on cows free of clinical signs and with records on up to 3 test-days before and after the date of the first bacteriological samples. Most bacteriological cultures were negative (52.38%), others contained either staphylococci (23.08%), streptococci (9.16%), mixed bacteria (8.79%) or were contaminated (6.59%). Only losses mediated by an increase in SCC were significantly different from null. In cows with three consecutive bacteriological positive results, we estimated a decreased milk yield of 0.28 kg per day for each unit increase in log2-transformed CFU that elicited one unit increase in log2-transformed SCC. In cows with one or two bacteriological positive results, indirect milk loss was not significantly different from null although test-day milk decreased by 0.74 kg per day for each unit increase of log2-transformed SCC. These results highlight the importance of milk losses that are mediated by an increase in SCC during mammary infection and the feasibility of decomposing total milk loss into its direct and indirect components. PMID:26923826

  20. Direct and Indirect Effects of Five Factor Personality and Gender on Depressive Symptoms Mediated by Perceived Stress

    PubMed Central

    Kim, Song E.; Cho, Juhee; Kwon, Min-Jung; Chang, Yoosoo; Ryu, Seungho; Shin, Hocheol

    2016-01-01

    This study was designed to investigate associations among five factor personality traits, perceived stress, and depressive symptoms and to examine the roles of personality and perceived stress in the relationship between gender and depressive symptoms. The participants (N = 3,950) were part of a cohort study for health screening and examination at the Kangbuk Samsung Hospital. Personality was measured with the Revised NEO Personality Inventory (NEO-PI-R). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Perceived stress level was evaluated with a self-reported stress questionnaire developed for the Korea National Health and Nutrition Examination Survey. A higher degree of neuroticism and lower degrees of extraversion, agreeableness, and conscientiousness were significantly associated with greater perceived stress and depressive symptoms. Neuroticism and extraversion had significant direct and indirect effects (via stress as a mediator) on depressive symptoms in both genders. Agreeableness and conscientiousness had indirect effects on depression symptoms in both genders. Multiple mediation models were used to examine the mediational roles of each personality factor and perceived stress in the link between gender and depressive symptoms. Four of the personality factors (except openness) were significant mediators, along with stress, on the relationship between gender and depressive symptoms. Our findings suggest that the links between personality factors and depressive symptoms are mediated by perceived stress. As such, personality is an important factor to consider when examining the link between gender and depression. PMID:27120051

  1. Direct and Indirect Effects of Five Factor Personality and Gender on Depressive Symptoms Mediated by Perceived Stress.

    PubMed

    Kim, Song E; Kim, Han-Na; Cho, Juhee; Kwon, Min-Jung; Chang, Yoosoo; Ryu, Seungho; Shin, Hocheol; Kim, Hyung-Lae

    2016-01-01

    This study was designed to investigate associations among five factor personality traits, perceived stress, and depressive symptoms and to examine the roles of personality and perceived stress in the relationship between gender and depressive symptoms. The participants (N = 3,950) were part of a cohort study for health screening and examination at the Kangbuk Samsung Hospital. Personality was measured with the Revised NEO Personality Inventory (NEO-PI-R). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression Scale (CES-D). Perceived stress level was evaluated with a self-reported stress questionnaire developed for the Korea National Health and Nutrition Examination Survey. A higher degree of neuroticism and lower degrees of extraversion, agreeableness, and conscientiousness were significantly associated with greater perceived stress and depressive symptoms. Neuroticism and extraversion had significant direct and indirect effects (via stress as a mediator) on depressive symptoms in both genders. Agreeableness and conscientiousness had indirect effects on depression symptoms in both genders. Multiple mediation models were used to examine the mediational roles of each personality factor and perceived stress in the link between gender and depressive symptoms. Four of the personality factors (except openness) were significant mediators, along with stress, on the relationship between gender and depressive symptoms. Our findings suggest that the links between personality factors and depressive symptoms are mediated by perceived stress. As such, personality is an important factor to consider when examining the link between gender and depression. PMID:27120051

  2. Indirect interband transition induced by optical near fields with large wave numbers

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Maiku; Nobusada, Katsuyuki

    2016-05-01

    Optical near fields (ONFs) have Fourier components with large wave numbers that are two or three orders of magnitude larger than those of far-field propagating light owing to their nonuniformity in space. By utilizing these large wave numbers, the ONF is expected to induce an indirect interband transition between Bloch states having different wave numbers and directly generate an electron-hole pair without electron-phonon coupling. We perform time-dependent dynamics calculations of a one-dimensional periodic potential with an indirect band-gap structure and demonstrate that the ONF definitely induces an indirect interband transition. Instead of using the general Bloch boundary condition, which is usually imposed in conventional band structure calculations, we adopt an alternative boundary condition, the Born-von Kármán boundary condition, to appropriately treat indirect interband transitions. The calculated absorption spectra for the far-field and ONF excitations show different absorption edges and spectral patterns. We argue that this difference can be experimentally measured as evidence of the effects of the large wave numbers of the ONF.

  3. Estrogen protects against dopamine neuron toxicity in primary mesencephalic cultures through an indirect P13K/Akt mediated astrocyte pathway.

    PubMed

    Bains, Mona; Roberts, James L

    2016-01-01

    Astrocytes regulate neuronal homeostasis and have been implicated in affecting the viability and functioning of surrounding neurons under stressed and injured conditions. Previous data from our lab suggests indirect actions of estrogen through ERα in neighboring astroglia to protect dopamine neurons against 1-methyl-4-phenylpyridinium (MPP(+)) toxicity in mouse mesencephalic cultures. We further evaluate estrogen signaling in astrocytes and the mechanism of estrogen's indirect neuroprotective effects on dopamine neurons. Primary mesencephalic cultures pre-treated with 17β-estradiol and the membrane impermeable estrogen, E2-BSA, were both neuroprotective against MPP(+) -induced dopamine neuron toxicity, suggesting membrane-initiated neuroprotection. ERα was found in the plasma membrane of astrocyte cultures and colocalized with the lipid raft marker, flotillin-1. A 17β-estradiol time course revealed a significant increase in Akt, which was inhibited by the PI3 kinase inhibitor, LY294004. Estrogen conditioned media collected from pure astrocyte cultures rescued glial deficient mesencephalic cultures from MPP(+). This indirect estrogen-mediated neuroprotective effect in mesencephalic cultures was significantly reduced when PI3 kinase signaling in astrocytes was blocked prior to collecting estrogen-conditioned media using the irreversible PI3 kinase inhibitor, Wortmannin. Estrogen signaling via astrocytes is rapidly initiated at the membrane level and requires PI3 kinase signaling in order to protect primary mesencephalic dopamine neurons from MPP(+) neurotoxicity. PMID:26520464

  4. Nrf2-Mediated HO-1 Induction Coupled with the ERK Signaling Pathway Contributes to Indirect Antioxidant Capacity of Caffeic Acid Phenethyl Ester in HepG2 Cells

    PubMed Central

    Kim, Jin-Kyoung; Jang, Hae-Dong

    2014-01-01

    The objective of this study is to investigate the contributing effect of the nuclear transcription factor-erythroid 2-related factor 2 (Nrf2)-mediated signaling pathway on the indirect antioxidant capacity of caffeic acid phenethyl ester (CAPE) against oxidative stress in HepG2 cells. The result of an antioxidant response element (ARE)-luciferase assay showed that CAPE stimulated ARE promoter activity resulting in increased transcriptional and translational activities of heme oxygenase-1 (HO-1). In addition, CAPE treatment enhanced Nrf2 accumulation in the nucleus and the post-translational phosphorylation level of extracellular signal-regulated kinase (ERK) among several protein kinases tested. Treatment with ERK inhibitor U126 completely suppressed CAPE-induced ERK phosphorylation and HO-1 expression, but it only partly inhibited CAPE-induced Nrf2 accumulation and ARE promoter. Using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) method, the cellular antioxidant capacity of CAPE against 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)- or H2O2-induced oxidative stress also was shown to be partially suppressed by the ERK inhibitor. From the overall results it is proposed that the indirect antioxidant activity of CAPE against oxidative stress in HepG2 cells is partially attributed to induction of HO-1, which is regulated by Kelch-like erythroid-cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1)-independent Nrf2 activation relying on post-translational phosphorylation of ERK. PMID:25007817

  5. Contrasting patterns of short-term indirect seed-seed interactions mediated by scatter-hoarding rodents.

    PubMed

    Xiao, Zhishu; Zhang, Zhibin

    2016-09-01

    It is well known that direct effects of seed predators or dispersers can have strong effects on seedling establishment. However, we have limited knowledge about the indirect species interactions between seeds of different species that are mediated by shared seed predators and/or dispersers and their consequences for plant demography and diversity. Because scatter-hoarding rodents as seed dispersers may leave some hoarded seeds uneaten, scatter hoarding may serve to increase seed survival and dispersal. Consequently, the presence of heterospecific seeds could alter whether the indirect interactions mediated by scatter-hoarding rodents have a net positive effect, creating apparent mutualism between seed species, or a net negative effect, creating apparent competition between seed species. We present a testable framework to measure short-term indirect effects between co-occurring plant species mediated by seed scatter-hoarding rodents. We tested this framework in a subtropical forest in south-west China using a replacement design and tracked the fate of individually tagged seeds in experimental patches. We manipulated the benefits to rodents by using low-tannin dormant chestnuts as palatable food and high-tannin non-dormant acorns as unpalatable food. We found that seed palatability changed the amount of scatter hoarding that occurred when seeds co-occurred either among or within patches. Consistent with our predictions, scatter-hoarding rodents created apparent mutualism through increasing seed removal and seed caching, and enhancing survival, of both plant species in mixed patches compared with monospecific patches. However, if we ignore scatter hoarding and treat all seed harvest as seed predation (and not dispersal), then apparent competition between palatable chestnuts and unpalatable acorns was also observed. This study is the first to demonstrate that foraging decisions by scatter-hoarding animals to scatter hoard seeds for later consumption (or loss) or

  6. Evidence for the indirect effects of perceived public stigma on psychosocial outcomes: The mediating role of self-stigma.

    PubMed

    Kao, Yu-Chen; Lien, Yin-Ju; Chang, Hsin-An; Wang, Sheng-Chiang; Tzeng, Nian-Sheng; Loh, Ching-Hui

    2016-06-30

    This study examined the possible mediating role of self-stigma in the relationship between perceived public stigma and psychosocial outcomes and how this mechanism may be contingent on illness severity in a non-Western (Chinese) sample. A total of 251 participants, namely 151 psychiatric outpatients with psychotic disorders and 100 psychiatric outpatients without psychotic disorders, completed a questionnaire on stigma and psychosocial outcomes that covered topics such as self-esteem, depressive symptoms, and subjective quality of life (QoL). Using a cross-sectional design, ordinary least squares regression and bootstrapping mediation analyses were used to test whether self-stigma mediated the relationship between perceived public stigma and psychosocial outcomes and whether this mediating process was moderated by diagnostic status. The results indicated that self-stigma mediated the effect of perceived public stigma on psychosocial outcomes such as self-esteem, depressive symptoms, and subjective QoL among both patients with psychotic disorders and those without psychotic disorders after controlling for demographic and clinical characteristics. Further, moderated mediation analyses revealed that the indirect effect of perceived public stigma on psychosocial outcomes were not moderated by the status of psychotic diagnoses. Self-stigma might be an essential and tractable target for interventions aimed at breaking the vicious cycle of discrimination and stigmatization toward people with mental illness regardless of their diagnoses. PMID:27111212

  7. Effect Size Measures for Mediation Models: Quantitative Strategies for Communicating Indirect Effects

    ERIC Educational Resources Information Center

    Preacher, Kristopher J.; Kelley, Ken

    2011-01-01

    The statistical analysis of mediation effects has become an indispensable tool for helping scientists investigate processes thought to be causal. Yet, in spite of many recent advances in the estimation and testing of mediation effects, little attention has been given to methods for communicating effect size and the practical importance of those…

  8. Magnetic field induced indirect gap in a modulation doped quantum well

    NASA Astrophysics Data System (ADS)

    Whittaker, D. M.; Fisher, T. A.; Simmonds, P. E.; Skolnick, M. S.; Smith, R. S.; Taylor, L. L.; Bass, S. J.

    1992-02-01

    We report the first experimental evidence for the indirect fundamental band-gap developed when an in-plane magnetic field is applied to a wide, modulation-doped quantum well. In such structures, band bending may cause the lowest energy electron and hole states to be spatially separated, which leads to an induced indirect gap proportional to the field. The corresponding photoluminescence peak undergoes a large, roughly quadratic shift with field, a consequence of the behaviour of the allowed transitions involving thermalised holes and electrons with finite k. This characteristic strong diamagnetic shift is observed in spectra from both asymmetric AlGaAs/InGaAs/GaAs strained layer structures and a very wide symmetric InGaAs/InP lattice matched well. The experimental results are shown to be in good agreement with realistic self consistent calculations of the band-structure.

  9. Soil-mediated indirect impacts of an invasive predator on plant growth

    PubMed Central

    Wardle, David A.; Bellingham, Peter J.; Fukami, Tadashi; Bonner, Karen I.

    2012-01-01

    While several studies have shown that invasive plant effects on soil biota influence subsequent plant performance, corresponding studies on how invasive animals affect plants through influencing soil biota are lacking. This is despite the fact that invasive animals often indirectly alter the below-ground subsystem. We studied 18 offshore islands in northern New Zealand, half of which have been invaded by rats that are predators of seabirds and severely reduce their densities, and half of which remain non-invaded; invasion of rats thwarts seabird transfer of resources from ocean to land. We used soil from each island in a glasshouse experiment involving soil sterilization treatments to determine whether rat invasion indirectly influences plant growth through the abiotic pathway (by impairing seabird-driven inputs to soil) or the biotic pathway (by altering the soil community). Rat invasion greatly impaired plant growth but entirely through the abiotic pathway. Plant growth was unaffected by the soil community or its response to invasion, meaning that the responses of plants and soil biota to invasion are decoupled. Our results provide experimental evidence for the powerful indirect effects that predator-instigated cascades can exert on plant and ecosystem productivity, with implications for the restoration of island ecosystems by predator removal. PMID:22496079

  10. Acrolein Causes TRPA1-Mediated Sensory Irritation and Indirect Potentiation of TRPV1-Mediated Pulmonary Chemoreflex Response

    EPA Science Inventory

    We previously demonstrated that acute exposure to acrolein causes immediate sensory irritation, with rapid decrease in heart rate (HR) and increase in inspiratory time (Ti), and potentiation of pulmonary chemoreflex response 24hrs later; of these effects only the latter is mediat...

  11. Indirect laser-induced breakdown of transparent thin gel layer for sensitive trace element detection

    NASA Astrophysics Data System (ADS)

    Xiu, Junshan; Bai, Xueshi; Negre, Erwan; Motto-Ros, Vincent; Yu, Jin

    2013-06-01

    Optical emissions from major and trace elements embodied in a transparent gel prepared from cooking oil were detected when the gel was spread in thin film on a metallic substrate and a plasma was induced on the substrate surface using nanosecond infrared pulsed laser. Such emissions are due to indirect breakdown of the coating layer. The generated plasma, a mixture of substances from the substrate, the layer, and the ambient gas, was characterized using emission spectroscopy. Temperature higher than 15 000 K determined in the plasma allows considering sensitive detection of trace elements in liquids, gels, biological samples, or thin films.

  12. Evaluation of fluorescent dye degradation indirectly induced by x-ray ionizing radiation.

    PubMed

    Benevides, Clayton Augusto; Duarte de Menezes, Frederico; de Araujo, Renato E

    2015-08-01

    This work evaluated the fluorescent dye degradation indirectly induced by ionizing radiation with high energy photons (50 keV). Aqueous gels of agarose with low concentrations of Rhodamine 6G and Fluorescein were submitted to doses of x-ray radiation up to 200 Gy. The dye degradation was analyzed by fluorescence spectroscopy, using an excitation light-emitting diode with a peak wavelength of 462 nm. A rate equation model of fluorophores and radicals' species populations was developed to describe the degradation time behavior of the fluorescent solutions. The model suggests fluorescent dyes should be used in dosimetry. PMID:26368112

  13. Interleukin-19 induces angiogenesis in the absence of hypoxia by direct and indirect immune mechanisms.

    PubMed

    Kako, Farah; Gabunia, Khatuna; Ray, Mitali; Kelemen, Sheri E; England, Ross N; Kako, Bashar; Scalia, Rosario G; Autieri, Michael V

    2016-06-01

    Neovascularization and inflammation are independent biological processes but are linked in response to injury. The role of inflammation-dampening cytokines in the regulation of angiogenesis remains to be clarified. The purpose of this work was to test the hypothesis that IL-19 can induce angiogenesis in the absence of tissue hypoxia and to identify potential mechanisms. Using the aortic ring model of angiogenesis, we found significantly reduced sprouting capacity in aortic rings from IL-19(-/-) compared with wild-type mice. Using an in vivo assay, we found that IL-19(-/-) mice respond to vascular endothelial growth factor (VEGF) significantly less than wild-type mice and demonstrate decreased capillary formation in Matrigel plugs. IL-19 signals through the IL-20 receptor complex, and IL-19 induces IL-20 receptor subunit expression in aortic rings and cultured human vascular smooth muscle cells, but not endothelial cells, in a peroxisome proliferator-activated receptor-γ-dependent mechanism. IL-19 activates STAT3, and IL-19 angiogenic activity in aortic rings is STAT3-dependent. Using a quantitative RT-PCR screening assay, we determined that IL-19 has direct proangiogenic effects on aortic rings by inducing angiogenic gene expression. M2 macrophages participate in angiogenesis, and IL-19 has indirect angiogenic effects, as IL-19-stimulated bone marrow-derived macrophages secrete proangiogenic factors that induce greater sprouting of aortic rings than unstimulated controls. Using a quantitative RT-PCR screen, we determined that IL-19 induces expression of angiogenic cytokines in bone marrow-derived macrophages. Together, these data suggest that IL-19 can promote angiogenesis in the absence of hypoxia by at least two distinct mechanisms: 1) direct effects on vascular cells and 2) indirect effects by stimulation of macrophages. PMID:27053520

  14. Trait-mediated indirect interactions of ant shape on the attack of caterpillars and fruits.

    PubMed

    Dáttilo, Wesley; Aguirre, Armando; De la Torre, Pedro Luna; Kaminski, Lucas A; García-Chávez, Juan; Rico-Gray, Víctor

    2016-08-01

    Mainly owing to their high diversity and abundance, ants are formidable as predators and defenders of foliage. Consequently, ants can exclude both invertebrate and vertebrate activity on plants via direct and indirect interactions as already shown in many previous studies. Here we present empirical evidence that objects resembling ant shape on dummy caterpillars were able to repel visually oriented predators. Moreover, we also show that rubber ants on dummy fruits can repel potential fruit dispersers. Our results have direct implications on the ecological and evolutionary dynamics of interactions in ant-based systems, as ant presence could affect the fitness of its partners. In short, our study highlights the importance of visual cues in interspecific interactions and opens a new way to study the effects of ant presence to test ecological and evolutionary hypotheses. PMID:27484648

  15. Direct and indirect mechanisms mediating apoptosis during HIV infection: contribution to in vivo CD4 T cell depletion.

    PubMed

    Gougeon, M L; Laurent-Crawford, A G; Hovanessian, A G; Montagnier, L

    1993-06-01

    The gradual depletion of CD4+ T lymphocytes during the development of AIDS may be due, at least in part, to a process referred to as apoptosis. This process involves a Ca2+ dependent nuclear endonuclease that cleaves the chromatin at internucleosomal junctions. In addition, we have recently provided evidence that apoptosis may be responsible not only for the progressive loss of CD4+ T lymphocytes but may be operative in CD8+ T lymphocytes as well. Here, we describe mechanisms which by direct and indirect pathways may induce apoptosis during HIV infection and thus leading to elimination of T cells. PMID:8102263

  16. Parasites of Trinidadian guppies: evidence for sex- and age-specific trait-mediated indirect effects of predators.

    PubMed

    Stephenson, Jessica F; van Oosterhout, Cock; Mohammed, Ryan S; Cable, Joanne

    2015-02-01

    Predation pressure can alter the morphology, physiology, life history, and behavior of prey; each of these in turn can change how surviving prey interact with parasites. These trait-mediated indirect effects may change in direction or intensity during growth or, in sexually dimorphic species, between the sexes. The Trinidadian guppy, Poecilia reticulata presents a unique opportunity to examine these interactions; its behavioral ecology has been intensively studied in wild populations with well-characterized predator faunas. Predation pressure is known to have driven the evolution of many guppy traits; for example, in high-predation sites, females (but not males) tend to shoal, and this anti-predator behavior facilitates parasite transmission. To test for evidence of predator-driven differences in infection in natural populations, we collected 4715 guppies from 62 sites across Trinidad between 2003 and 2009 and screened them for ectosymbionts, including Gyrodactylus. A novel model-averaging analysis revealed that females were more likely to be infected with Gyrodactylus parasites than males, but only in populations with both high predation pressure and high infection prevalence. We propose that the difference in shoaling tendency between the sexes could explain the observed difference in infection prevalence between males and females in high-predation sites. The infection rate of juveniles did not vary with predation regime, probably because juveniles face constant predation pressure from conspecific adults and therefore tend to shoal in both high- and low-predation sites. This represents the first evidence for age- and sex-specific trait-mediated indirect effects of predators on the probability of infection in their prey. PMID:26240870

  17. Probability of failure in BWR reactor coolant piping: Guillotine break indirectly induced by earthquakes

    SciTech Connect

    Hardy, G.S.; Campbell, R.D.; Ravindra, M.K.

    1986-12-01

    The requirements to design nuclear power plants for the effects of an instantaneous double-ended guillotine break (DEGB) of the reactor coolant piping have led to excessive design costs, interference with normal plant operation and maintenance, and unnecessary radiation exposure of plant maintenance personnel. This report describes an aspect of the NRC/Lawrence Livermore National laboratory-sponsored research program aimed at investigating whether the probability of DEGB in Reactor Coolant Loop Piping of nuclear power plants is acceptably small such that the requirements to design for the DEGB effects (e.g., provision of pipe whip restraints) may be removed. This study estimates the probability of indirect DEGB in Reactor Coolant piping as a consequence of seismic-induced structural failures within the containment of the GE supplied boiling water reactor at the Brunswick nuclear power plant. The median probability of indirect DEGB was estimated to be 2 x 10/sup -8/ per year. Using conservation assumptions, the 90% subjective probability value (confidence) of P/sub DEGB/ was found to be less than 5 x 10/sup -7/ per year.

  18. Long noncoding RNA hotair mediated angiogenesis in nasopharyngeal carcinoma by direct and indirect signaling pathways

    PubMed Central

    Hu, Bao-guang; Liang, Wei-cheng; Zhu, Xiao; Yang, Hai-di; Li, Gang; Zhang, Jin-fang

    2016-01-01

    Nasopharyngeal carcinoma (NPC), as a unique head and neck cancer type, is particularly prevalent in certain geographic areas such as eastern Asia. Until now, the therapeutic options have been restricted mainly to radiotherapy or chemotherapy. However, the clinical treatment effect remains unsatisfactory even if the combined radio-chemotherapies. Therefore, it is urgently needed to develop effective novel therapies against NPC. In this study, we discovered that lncRNA Hotair was extremely abundant in NPC cells and clinical NPC samples. Further studies showed that Hotair knockdown significantly attenuated both in vitro and in vivo tumor cell growth and angiogenesis. Our study also demonstrated that Hotair promoted angiogenesis through directly activating the transcription of angiogenic factor VEGFA as well as through GRP78-mediated upregulation of VEGFA and Ang2 expression. Therefore, Hotair may serve as a promising diagnostic marker and therapeutic target for NPC patients. PMID:26717040

  19. Tunable indirect magnetic interaction mediated by spin-orbit coupled electrons in quantum well

    NASA Astrophysics Data System (ADS)

    Sun, Yi-Qian; Lyu, Pin

    2015-01-01

    By taking into account the quantum confinement, we calculated the Ruderman-Kittel-Kasuya-Yosida (RKKY) magnetic interaction between two magnetic impurities mediated by electrons with Rashba and Dresselhaus spin-orbit couplings in a quantum well. The RKKY magnetic interaction of the present system consists of conventional RKKY magnetic coupling, anisotropic magnetic couplings and Dzyaloshinsky-Moriya magnetic interaction. The above magnetic interactions strongly depend not only on the spin-orbit coupling strength, but also on the confined width and the absolute positions of two localized spins in the direction perpendicular to the plane of the layered structure due to the quantum size effect. It provides a potential way to control the RKKY magnetic interaction and its components in the quantum well with Rashba spin-orbit coupling by both the applied gate voltage and the nanostructure geometry.

  20. Optically and thermally controlled terahertz metamaterial via transition between direct and indirect electromagnetically induced transparency

    SciTech Connect

    Sui, Jiawei Feng, Ls

    2014-12-15

    This passage presents a design of tunable terahertz metamaterials via transition between indirect and direct electromagnetically induced transparency (EIT) effects by changing semiconductor InSb’s properties to terahertz wave under optical and thermal stimuli. Mechanical model and its electrical circuit model are utilized in analytically calculating maximum transmission of transparency window. Simulated results show consistency with the analytical expressions. The results show that the metamaterials hold 98.4% modulation depth at 189 GHz between 300 K, σ{sub InSb} =256000 S/m, and 80 K, σ{sub InSb} =0.0162 S/m conditions , 1360 ps recovery time of the excited electrons in InSb under optical stimulus at 300 K mainly considering the direct EIT effect, and minimum bandwidth 1 GHz.

  1. Extracorporeal shock waves stimulate frog sciatic nerves indirectly via a cavitation-mediated mechanism.

    PubMed Central

    Schelling, G.; Delius, M.; Gschwender, M.; Grafe, P.; Gambihler, S.

    1994-01-01

    Shock waves (SWs) are single pressure pulses with amplitudes up to over 100 MPa, a rise time of only a few nanoseconds, and a short duration of approximately 2 microseconds. Their clinical application for stone destruction causes pain, indicating nerve stimulation by SWs. To examine this phenomenon, sciatic nerves of frogs were exposed to SWs in an organ bath. The SWs were generated with an experimental Dornier lithotripter model XL1 at an operating voltage of 15 kV. The nerves were mounted in a chamber which allowed electrical nerve stimulation and the registration of electrically and SW-induced compound action potentials (SWCAPs). The chamber was filled with frog Ringer's solution. In a standardized protocol. The first experiment established that 95.0 +/- 4.7% of administered SWs induced action potentials which were lower in amplitude (1.45 +/- 1.14 versus 1.95 +/- 0.95 mV, p = 0.004) but similar in shape to electrically induced compound action potentials. In a second experiment, it was shown that the site of origin of the SWCAPs could be correctly determined by simultaneous recording of action potentials at both ends of the nerve. The mechanism of shock wave stimulation was examined by experiments 3 and 4. In experiment 3, in contrast to the previous experiments, SW exposure of the nerves was performed 6 cm outside the shock wave focus. This resulted in a mean probability of inducing a SWCAP of only 4%. After gas bubble administration, this probability increased to 86% for the first SW released immediately after bubble application and declined to 56% for the second, 21% for the third, to 0 for the 10th SW after fluid injection. This indicates that cavitation, the interaction between shock waves and gas bubbles in fluid or tissues, was involved in SWCAP generation. In experiment 4, nerves were again exposed in the focus, however, the Ringer's solution surrounding the nerve was replaced by polyvinyl alcohol (PVA). PVA is a solution with low cavitation activity

  2. An Apparent Trade-Off between Direct and Signal-Based Induced Indirect Defence against Herbivores in Willow Trees

    PubMed Central

    Yoneya, Kinuyo; Uefune, Masayoshi; Takabayashi, Junji

    2012-01-01

    Signal-based induced indirect defence refers to herbivore-induced production of plant volatiles that attract carnivorous natural enemies of herbivores. Relationships between direct and indirect defence strategies were studied using tritrophic systems consisting of six sympatric willow species, willow leaf beetles (Plagiodera versicolora), and their natural predators, ladybeetles (Aiolocaria hexaspilota). Relative preferences of ladybeetles for prey-infested willow plant volatiles, indicating levels of signal-based induced indirect defence, were positively correlated with the vulnerability of willow species to leaf beetles, assigned as relative levels of direct defence. This correlation suggested a possible trade-off among the species, in terms of resource limitation between direct defence and signal-based induced indirect defence. However, analyses of volatiles from infested and uninfested plants showed that the specificity of infested volatile blends (an important factor determining the costs of signal-based induced indirect defence) did not affect the attractiveness of infested plant volatiles. Thus, the suggested trade-off in resource limitation was unlikely. Rather, principal coordinates analysis showed that this ‘apparent trade-off’ between direct and signal-based induced indirect defence was partially explained by differential preferences of ladybeetles to infested plant volatiles of the six willow species. We also showed that relative preferences of ladybeetles for prey-infested willow plant volatiles were positively correlated with oviposition preferences of leaf beetles and with the distributions of leaf beetles in the field. These correlations suggest that ladybeetles use the specificity of infested willow plant volatiles to find suitable prey patches. PMID:23251559

  3. Cascading trait-mediated interactions induced by ant pheromones.

    PubMed

    Hsieh, Hsun-Yi; Liere, Heidi; Soto, Estelí J; Perfecto, Ivette

    2012-09-01

    Trait-mediated indirect interactions (TMII) can be as important as density-mediated indirect interactions. Here, we provide evidence for a novel trait-mediated cascade (where one TMII affects another TMII) and demonstrate that the mechanism consists of a predator eavesdropping on chemical signaling. Ants protect scale insects from predation by adult coccinellid beetles - the first TMII. However, parasitic phorid flies reduce ant foraging activity by 50% - the second TMII, providing a window of opportunity for female beetles to oviposit in high-quality microsites. Beetle larvae are protected from ant predation and benefit from living in patches with high scale densities. We demonstrate that female beetles can detect pheromones released by the ant when attacked by phorids, and that only females, and especially gravid females, are attracted to the ant pheromone. As ants reduce their movement when under attack by phorids, we conclude that phorids facilitate beetle oviposition, thus producing the TMII cascade. PMID:23139877

  4. Cascading trait-mediated interactions induced by ant pheromones

    PubMed Central

    Hsieh, Hsun-Yi; Liere, Heidi; Soto, Estelí J; Perfecto, Ivette

    2012-01-01

    Trait-mediated indirect interactions (TMII) can be as important as density-mediated indirect interactions. Here, we provide evidence for a novel trait-mediated cascade (where one TMII affects another TMII) and demonstrate that the mechanism consists of a predator eavesdropping on chemical signaling. Ants protect scale insects from predation by adult coccinellid beetles – the first TMII. However, parasitic phorid flies reduce ant foraging activity by 50% – the second TMII, providing a window of opportunity for female beetles to oviposit in high-quality microsites. Beetle larvae are protected from ant predation and benefit from living in patches with high scale densities. We demonstrate that female beetles can detect pheromones released by the ant when attacked by phorids, and that only females, and especially gravid females, are attracted to the ant pheromone. As ants reduce their movement when under attack by phorids, we conclude that phorids facilitate beetle oviposition, thus producing the TMII cascade. PMID:23139877

  5. The indirect NMDAR inhibitor flupirtine induces sustained post-ischemic recovery, neuroprotection and angioneurogenesis.

    PubMed

    Jaeger, Hanna M; Pehlke, Jens R; Kaltwasser, Britta; Kilic, Ertugrul; Bähr, Mathias; Hermann, Dirk M; Doeppner, Thorsten R

    2015-06-10

    N-methyl-D-aspartate receptor (NMDAR) activation induces excitotoxicity, contributing to post-stroke brain injury. Hitherto, NMDAR deactivation failed in clinical trials due to insufficient pre-clinical study designs and drug toxicity. Flupirtine is an indirect NMDAR antagonist being used as analgesic in patients. Taking into account its tolerability profile, we evaluated effects of flupirtine on post-stroke tissue survival, neurological recovery and brain remodeling.Mice were exposed to stroke and intraperitoneally treated with saline (control) or flupirtine at various doses (1-10 mg/kg) and time-points (0-12 hours). Tissue survival and cell signaling were studied on day 2, whereas neurological recovery and tissue remodeling were analyzed until day 84.Flupirtine induced sustained neuroprotection, when delivered up to 9 hours. The latter yielded enhanced neurological recovery that persisted over three months and which was accompanied by enhanced angioneurogenesis. On the molecular level, inhibition of calpain activation was noted, which was associated with increased signal-transducer-and-activator-of-transcription-6 (STAT6) abundance, reduced N-terminal-Jun-kinase and NF-κB activation, as well as reduced proteasomal activity. Consequently, blood-brain-barrier integrity was stabilized, oxidative stress was reduced and brain leukocyte infiltration was diminished.In view of its excellent tolerability, considering its sustained effects on neurological recovery, brain tissue survival and remodeling, flupirtine is an attractive candidate for stroke therapy. PMID:26050199

  6. The indirect NMDAR inhibitor flupirtine induces sustained post-ischemic recovery, neuroprotection and angioneurogenesis

    PubMed Central

    Jaeger, Hanna M.; Pehlke, Jens R.; Kaltwasser, Britta; Kilic, Ertugrul; Bähr, Mathias; Hermann, Dirk M.; Doeppner, Thorsten R.

    2015-01-01

    N-methyl-D-aspartate receptor (NMDAR) activation induces excitotoxicity, contributing to post-stroke brain injury. Hitherto, NMDAR deactivation failed in clinical trials due to insufficient pre-clinical study designs and drug toxicity. Flupirtine is an indirect NMDAR antagonist being used as analgesic in patients. Taking into account its tolerability profile, we evaluated effects of flupirtine on post-stroke tissue survival, neurological recovery and brain remodeling. Mice were exposed to stroke and intraperitoneally treated with saline (control) or flupirtine at various doses (1-10 mg/kg) and time-points (0-12 hours). Tissue survival and cell signaling were studied on day 2, whereas neurological recovery and tissue remodeling were analyzed until day 84. Flupirtine induced sustained neuroprotection, when delivered up to 9 hours. The latter yielded enhanced neurological recovery that persisted over three months and which was accompanied by enhanced angioneurogenesis. On the molecular level, inhibition of calpain activation was noted, which was associated with increased signal-transducer-and-activator-of-transcription-6 (STAT6) abundance, reduced N-terminal-Jun-kinase and NF-κB activation, as well as reduced proteasomal activity. Consequently, blood-brain-barrier integrity was stabilized, oxidative stress was reduced and brain leukocyte infiltration was diminished. In view of its excellent tolerability, considering its sustained effects on neurological recovery, brain tissue survival and remodeling, flupirtine is an attractive candidate for stroke therapy. PMID:26050199

  7. Systems Biology Reveals Cigarette Smoke-Induced Concentration-Dependent Direct and Indirect Mechanisms That Promote Monocyte-Endothelial Cell Adhesion.

    PubMed

    Poussin, Carine; Laurent, Alexandra; Peitsch, Manuel C; Hoeng, Julia; De Leon, Hector

    2015-10-01

    Cigarette smoke (CS) affects the adhesion of monocytes to endothelial cells, a critical step in atherogenesis. Using an in vitro adhesion assay together with innovative computational systems biology approaches to analyze omics data, our study aimed at investigating CS-induced mechanisms by which monocyte-endothelial cell adhesion is promoted. Primary human coronary artery endothelial cells (HCAECs) were treated for 4 h with (1) conditioned media of human monocytic Mono Mac-6 (MM6) cells preincubated with low or high concentrations of aqueous CS extract (sbPBS) from reference cigarette 3R4F for 2 h (indirect treatment, I), (2) unconditioned media similarly prepared without MM6 cells (direct treatment, D), or (3) freshly generated sbPBS (fresh direct treatment, FD). sbPBS promoted MM6 cells-HCAECs adhesion following I and FD, but not D. In I, the effect was mediated at a low concentration through activation of vascular inflammation processes promoted in HCAECs by a paracrine effect of the soluble mediators secreted by sbPBS-treated MM6 cells. Tumor necrosis factor α (TNFα), a major inducer, was actually shed by unstable CS compound-activated TNFα-converting enzyme. In FD, the effect was triggered at a high concentration that also induced some toxicity. This effect was mediated through an yet unknown mechanism associated with a stress damage response promoted in HCAECs by unstable CS compounds present in freshly generated sbPBS, which had decayed in D unconditioned media. Aqueous CS extract directly and indirectly promotes monocytic cell-endothelial cell adhesion in vitro via distinct concentration-dependent mechanisms. PMID:26141392

  8. Reactor Materials Program probability of indirectly--induced failure of L and P reactor process water piping

    SciTech Connect

    Daugherty, W.L.

    1988-03-11

    The design basis accident for the Savannah River Production Reactors is the abrupt double-ended guillotine break (DEGB) of a large process water pipe. This accident is not considered credible in light of the low applied stresses and the inherent ductility of the piping material. The Reactor Materials Program was initiated to provide the technical basis for an alternate credible design basis accident. One aspect of this work is to determine the probability of the DEGB; to show that in addition to being incredible, it is also highly improbable. The probability of a DEGB is broken into two parts: failure by direct means, and indirectly-induced failure. Failure of the piping by direct means can only be postulated to occur if an undetected crack grows to the point of instability, causing a large pipe break. While this accident is not as severe as a DEGB, it provides a conservative upper bound on the probability of a direct DEGB of the piping. The second part of this evaluation calculates the probability of piping failure by indirect causes. Indirect failure of the piping can be triggered by an earthquake which causes other reactor components or the reactor building to fall on the piping or pull it from its supports. Since indirectly-induced failure of the piping will not always produce consequences as severe as a DEGB, this gives a conservative estimate of the probability of an indirectly- induced DEGB. This second part, indirectly-induced pipe failure, is the subject of this report. Failure by seismic loads in the piping itself will be covered in a separate report on failure by direct causes. This report provides a detailed evaluation of L reactor. A walkdown of P reactor and an analysis of the P reactor building provide the basis for extending the L reactor results to P reactor.

  9. An indirect electric field-induced control in directional migration of rat mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Park, Hyoun-Hyang; Jo, Sungkwon; Hoon Seo, Cheong; Jeong, Je Hoon; Yoo, Yeong-Eun; Lee, Dae Hoon

    2014-12-01

    We present the efficacy of an indirect E-field on the directional migration of rat mesenchymal stem cell (MSC). To avoid current flow through culture media and cell, E-fields were generated without exposing electrodes directly to the cell media. MSC migration was observed during wound closure in presence of indirect E-field. MSC migration depended on the E-field strength and occurs predominantly in the anodal direction. Indirect E-field therapy proved as tentative tool for controlled cell movement and healing.

  10. A case of oxaliplatin-induced immune-mediated thrombocytopenia

    PubMed Central

    Suh, Seong Eun; Jang, Moon Ju; Chong, So Young; Aster, Richard H.; Curtis, Brian R.

    2014-01-01

    Oxaliplatin is a platinum compound used in patients with gastrointestinal malignancies. It is known to evoke a drug-induced immune-mediated thrombocytopenia, which has not been reported in Korea. We describe a 53-year-old man who developed oxaliplatin-induced immune-mediated thrombocytopenia during chemotherapy for colon cancer. Oxaliplatin-dependent IgG platelet antibodies were detected in his serum on flow cytometry. He was treated with immunoglobulin and corticosteroids without any complications. Physicians should consider oxaliplatin-induced immune-mediated thrombocytopenia, when a sudden, isolated thrombocytopenia develops during chemotherapy with oxaliplatin. PMID:24724069

  11. Can We Improve Structured Sequence Processing? Exploring the Direct and Indirect Effects of Computerized Training Using a Mediational Model

    PubMed Central

    Smith, Gretchen N. L.; Conway, Christopher M.; Bauernschmidt, Althea; Pisoni, David B.

    2015-01-01

    Recent research suggests that language acquisition may rely on domain-general learning abilities, such as structured sequence processing, which is the ability to extract, encode, and represent structured patterns in a temporal sequence. If structured sequence processing supports language, then it may be possible to improve language function by enhancing this foundational learning ability. The goal of the present study was to use a novel computerized training task as a means to better understand the relationship between structured sequence processing and language function. Participants first were assessed on pre-training tasks to provide baseline behavioral measures of structured sequence processing and language abilities. Participants were then quasi-randomly assigned to either a treatment group involving adaptive structured visuospatial sequence training, a treatment group involving adaptive non-structured visuospatial sequence training, or a control group. Following four days of sequence training, all participants were assessed with the same pre-training measures. Overall comparison of the post-training means revealed no group differences. However, in order to examine the potential relations between sequence training, structured sequence processing, and language ability, we used a mediation analysis that showed two competing effects. In the indirect effect, adaptive sequence training with structural regularities had a positive impact on structured sequence processing performance, which in turn had a positive impact on language processing. This finding not only identifies a potential novel intervention to treat language impairments but also may be the first demonstration that structured sequence processing can be improved and that this, in turn, has an impact on language processing. However, in the direct effect, adaptive sequence training with structural regularities had a direct negative impact on language processing. This unexpected finding suggests that

  12. The respective effects of direct and indirect couplings on the plasmon-induced transparency in waveguide systems

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Li, Guanhai; Wang, Lin; Li, Hongjian; Chen, Xiaoshuang

    2016-04-01

    We investigate respectively the effects of direct and indirect couplings on electromagnetically induced transparency (EIT)-like in a Metal-Insulator-Metal (MIM) bus waveguide coupled to two aperture-resonators (ARS). Adjusting the intensity of direct and indirect couplings, we can intentionally realize, modulate and eliminate the EIT-like transmission in the proposed plasmonic structures. The consistency between theoretical results and finite-difference time-domain (FDTD) simulations indicates that the direct coupling can give rise to EIT-like phenomenon in symmetrical structure. Moreover, the EIT-like transmission dips can be shifted back to the original resonant frequency when the two couplings offset each other. These results may provide a helpful guideline for the control of light in highly integrated optical circuits.

  13. Time-scale dependency of host plant biomass- and trait-mediated indirect effects of deer herbivory on a swallowtail butterfly.

    PubMed

    Takagi, Shun; Miyashita, Tadashi

    2015-11-01

    Despite recent attempts to quantify the relative strength of density- and trait-mediated indirect effects, rarely has the issue been properly addressed at the population level. Most research is based on short-term small-scale experiments in which behavioural and/or physiological responses prevail. Here, we estimated the time-scales during which density- and trait-mediated effects manifest, as well as the strength of these effects, using an interaction chain with three organisms (deer-plant-butterfly). A hierarchical Bayesian model was performed by using a long-term data set of deer density in the Boso Peninsula, central Japan (where local densities differ spatially and temporally) as well as densities of the swallowtail butterfly Byasa alcinous and its host plant Aristolochia kaempferi. The time-scale effect of deer on plant quantity and quality was estimated according to the degree of carry-over effects. The negative influence on leaf density showed a temporal saturation pattern over the long term, while the positive influence on leaf quality due to resprouting of leaves after deer browsing showed no clear temporal trend. The net indirect effect changed from positive to negative with time, with the negative density-mediated effect becoming prominent in the long term. Our novel approach is widely applicable in assessing the dynamic impacts of wildlife if the spatio-temporal variability of expansion and/or invasion history is known. PMID:26114858

  14. The Indirect Effect of Alcohol Use on GPA in First-Semester College Students: The Mediating Role of Academic Effort

    ERIC Educational Resources Information Center

    Conway, James M.; DiPlacido, Joanne

    2015-01-01

    This study focused on first-semester college students, investigating (a) indirect effects of aggregate alcohol use on grade point average (GPA) through academic effort (skipping class and time on schoolwork) and (b) daily effects of alcohol use on reduced effort. Eighty students reported daily alcohol use and academic effort (skipping class and…

  15. Optically Induced Indirect Photonic Transitions in a Slow Light Photonic Crystal Waveguide

    NASA Astrophysics Data System (ADS)

    Castellanos Muñoz, Michel; Petrov, Alexander Yu.; O'Faolain, Liam; Li, Juntao; Krauss, Thomas F.; Eich, Manfred

    2014-02-01

    We demonstrate indirect photonic transitions in a silicon slow light photonic crystal waveguide. The transitions are driven by an optically generated refractive index front that moves along the waveguide and interacts with a signal pulse copropagating in the structure. We experimentally confirm a theoretical model which indicates that the ratio of the frequency and wave vector shifts associated with the indirect photonic transition is identical to the propagation velocity of the refractive index front. The physical origin of the transitions achieved here is fundamentally different than in previously proposed refractive index modulation concepts with fixed temporal and spatial modulation frequencies; as here, the interaction with the refractive index front results in a Doppler-like signal frequency and wave vector shift. Consequently, the bandwidth over which perfect mode frequency and wave vector matching is achieved is not intrinsically limited by the shape of the photonic bands, and tuning of the indirect photonic transitions is possible without any need for geometrical modifications of the structure. Our device is genuinely nonreciprocal, as it provides different frequency shifts for co- and counterpropagating signal and index fronts.

  16. Astroglial U87 Cells Protect Neuronal SH-SY5Y Cells from Indirect Effect of Radiation by Reducing DNA Damage and Inhibiting Fas Mediated Apoptotic Pathway in Coculture System.

    PubMed

    Saeed, Yasmeen; Rehman, Abdul; Xie, Bingjie; Xu, Jin; Hong, Ma; Hong, Qing; Deng, Yulin

    2015-08-01

    Recent studies provide the evidence that indirect effects of radiation could lead to neuronal cells death but underlying mechanism is not completely understood. On the other hand astroglial cells are known to protect neuronal cells against stress conditions in vivo and invitro. Yet, the fate of neuronal cells and the neuroprotective effect of coculture system (with glial cells) in response to indirect radiation exposure remain rarely discussed. Here, we purpose that the indirect effect of radiation may induce DNA damage by cell cycle arrest and receptor mediated apoptotic cascade which lead to apoptotic death of neuronal SH-SY5Y cells. We also hypothesized that coculture (with glial U87) may relieved the neuronal SH-SY5Y cells from toxicity of indirect effects radiation by reducing DNA damage and expression of apoptotic proteins in vitro. In the present study irradiated cell conditioned medium (ICCM) was used as source of indirect effect of radiation. Neuronal SH-SY5Y cells were exposed to ICCM with and without coculture with (glial U87) in transwell coculture system respectively. Various endpoints such as, cell survival number assay, Annexin V/PI assay, cell cycle analysis by flow cytometer, mRNA level of Fas receptor by q RT-PCR, expression of key apoptotic proteins by western blot and estimation of neurotrophic factors by ELISA method were analyzed into neuronal SH-SY5Y cells with and without co culture after ICCM exposure respectively. We found that ICCM induced DNA damage in neuronal SH-SY5Y cells by significant increase in cell cycle arrest at S-phase (***P < 0.001) which was further supported by over expression of P53 protein (**P < 0.01). While coculture (with glial U87), significantly reduced the ICCM induced cell cycle arrest and expression of P53 ((###) P < 0.001) neuronal SH-SY5Y cells. Further investigation of the underlying apoptotic mechanism revealed that in coculture system; ICCM induced elevated level of FAS mRNA level was significantly reduced

  17. Levodopa-Induced Dyskinesia Is Related to Indirect Pathway Medium Spiny Neuron Excitotoxicity: A Hypothesis Based on an Unexpected Finding

    PubMed Central

    Ivanova, Svetlana A.

    2016-01-01

    A serendipitous pharmacogenetic finding links the vulnerability to developing levodopa-induced dyskinesia to the age of onset of Huntington's disease. Huntington's disease is caused by a polyglutamate expansion of the protein huntingtin. Aberrant huntingtin is less capable of binding to a member of membrane-associated guanylate kinase family (MAGUKs): postsynaptic density- (PSD-) 95. This leaves more PSD-95 available to stabilize NR2B subunit carrying NMDA receptors in the synaptic membrane. This results in increased excitotoxicity for which particularly striatal medium spiny neurons from the indirect extrapyramidal pathway are sensitive. In Parkinson's disease the sensitivity for excitotoxicity is related to increased oxidative stress due to genetically determined abnormal metabolism of dopamine or related products. This probably also increases the sensitivity of medium spiny neurons for exogenous levodopa. Particularly the combination of increased oxidative stress due to aberrant dopamine metabolism, increased vulnerability to NMDA induced excitotoxicity, and the particular sensitivity of indirect pathway medium spiny neurons for this excitotoxicity may explain the observed increased prevalence of levodopa-induced dyskinesia. PMID:27144051

  18. Indirect global warming effects of ozone and stratospheric water vapor induced by surface methane emission

    SciTech Connect

    Wuebbles, D.J.; Grossman, A.S.; Tamaresis, J.S.; Patten, K.O. Jr.; Jain, A.; Grant, K.A.

    1994-07-01

    Methane has indirect effects on climate due to chemical interactions as well as direct radiative forcing effects as a greenhouse gas. We have calculated the indirect, time-varying tropospheric radiative forcing and GWP of O{sub 3} and stratospheric H{sub 2}O due to an impulse of CH{sub 4}. This impulse, applied to the lowest layer of the atmosphere, is the increase of the atmospheric mass of CH{sub 4} resulting from a 25 percent steady state increase in the current emissions as a function of latitude. The direct CH{sub 4} radiative forcing and GWP are also calculated. The LLNL 2-D radiative-chemistry-transport model is used to evaluate the resulting changes in the O{sub 3}, H{sub 2}O and CH{sub 4} atmospheric profiles as a function of time. A correlated k-distribution radiative transfer model is used to calculate the radiative forcing at the tropopause of the globally-averaged atmosphere profiles. The O{sub 3} indirect GWPs vary from {approximately}27 after a 20 yr integration to {approximately}4 after 500 years, agreeing with the previous estimates to within about 10 percent. The H{sub 2}O indirect GWPs vary from {approximately}2 after a 20 yr integration to {approximately}0.3 after 500 years, and are in close agreement with other estimates. The CH{sub 4} GWPs vary from {approximately}53 at 20 yrs to {approximately}7 at 500 yrs. The 20 year CH{sub 4} GWP is {approximately}20% larger than previous estimates of the direct CH{sub 4} GWP due to a CH{sub 4} response time ({approximately}17 yrs) that is much longer than the overall lifetime (10 yrs). The increased CH{sub 4} response time results from changes in the OH abundances caused by the CH{sub 4} impulse. The CH{sub 4} radiative forcing results are consistent with IPCC values. Estimates are made of latitude effects in the radiative forcing calculations, and UV effects on the O{sub 3} radiative forcing calculations (10%).

  19. Physiological mechanisms mediating aspartame-induced satiety.

    PubMed

    Hall, W L; Millward, D J; Rogers, P J; Morgan, L M

    2003-04-01

    Aspartame has been previously shown to increase satiety. This study aimed to investigate a possible role for the satiety hormones cholecystokinin (CCK) and glucagon-like peptide-1 (GLP-1) in this effect. The effects of the constituents of aspartame, phenylalanine and aspartic acid, were also examined. Six subjects consumed an encapsulated preload consisting of either 400 mg aspartame, 176 mg aspartic acid+224 mg phenylalanine, or 400 mg corn flour (control), with 1.5 g paracetamol dissolved in 450 ml water to measure gastric emptying. A 1983-kJ liquid meal was consumed 60 min later. Plasma CCK, GLP-1, glucose-dependent insulinotropic polypeptide (GIP), glucose, and insulin were measured over 0-120 min. Gastric emptying was measured from 0 to 60 min. Plasma GLP-1 concentrations decreased following the liquid meal (60-120 min) after both the aspartame and amino acids preloads (control, 2096.9 pmol/l min; aspartame, 536.6 pmol/l min; amino acids, 861.8 pmol/l min; incremental area under the curve [AUC] 60-120 min, P<.05). Desire to eat was reduced from 60 to 120 min following the amino acids preload (control, -337.1 mm min; aspartame, -505.4 mm min; amino acids, -1497.1 mm min; incremental AUC 60-120 min, P<.05). However, gastric emptying rates, plasma CCK, GIP, insulin, and glucose concentrations were unaffected. There was a correlation between the increase in plasma phenylalanine and decrease in desire to eat after the liquid meal following the constituent amino acids (r=-.9774, P=.004). In conclusion, it is unlikely that aspartame increases satiety via CCK- or GLP-1-mediated mechanisms, but small changes in circulating phenylalanine concentrations may influence appetite. PMID:12782208

  20. Prostacyclin-induced hyperthermia - Implication of a protein mediator

    NASA Technical Reports Server (NTRS)

    Kandasamy, S. B.; Williams, B. A.

    1982-01-01

    The mechanism of the prostacyclin-linked hyperthermia is studied in rabbits. Results show that intracerebroventricular administration of prostacyclin (PGI2) induces dose-related hyperthermia at room temperature (21 C), as well as at low (4 C) and high (30 C) ambient temperatures. It is found that this PGI2-induced hyperthermia is not mediated by its stable metabolite 6-keto prostaglandin F-1(alpha). Only one of the three anion transport systems, the liver transport system, appears to be important to the central inactivation of pyrogen, prostaglandin E2, and PGI2. Phenoxybenzamine and pimozide have no thermolytic effect on PGI2-induced hyperthermia, while PGI2 still induces hyperthermia after norepinephrine (NE) and dopamine levels are depleted by 6-hydroxydopamine. Indomethacin and SC-19220 (a PG antagonist) do not antagonize PGI2 induced hyperthermia, while theophylline does not accentuate the PGI2-induced hyperthermia. However, the hyperthermic response to PGI2 is attenuated by central administration of the protein synthesis inhibitor, anisomycin. It is concluded that PGI2-induced hyperthermia is not induced by NE, dopamine, or cyclic AMP, but rather that a protein mediator is implicated in the induction of fever by PG12.

  1. A principal stratification approach for evaluating natural direct and indirect effects in the presence of treatment-induced intermediate confounding.

    PubMed

    Taguri, Masataka; Chiba, Yasutaka

    2015-01-15

    Recently, several authors have shown that natural direct and indirect effects (NDEs and NIEs) can be identified under the sequential ignorability assumptions, as long as there is no mediator-outcome confounder that is affected by the treatment. However, if such a confounder exists, NDEs and NIEs will generally not be identified without making additional identifying assumptions. In this article, we propose novel identification assumptions and estimators for evaluating NDEs and NIEs under the usual sequential ignorability assumptions, using the principal stratification framework. It is assumed that the treatment and the mediator are dichotomous. We must impose strong assumptions for identification. However, even if these assumptions were violated, the bias of our estimator would be small under typical conditions, which can be easily evaluated from the observed data. This conjecture is confirmed for binary outcomes by deriving the bounds of the bias terms. In addition, the advantage of our estimator is illustrated through a simulation study. We also propose a method of sensitivity analysis that examines what happens when our assumptions are violated. We apply the proposed method to data from the National Center for Health Statistics. PMID:25312003

  2. Drug-Induced Glomerular Disease: Immune-Mediated Injury

    PubMed Central

    Markowitz, Glen S.; Radhakrishnan, Jai

    2015-01-01

    Drug-induced autoimmune disease was initially described decades ago, with reports of vasculitis and a lupus-like syndrome in patients taking hydralazine, procainamide, and sulfadiazine. Over the years, multiple other agents have been linked to immune-mediated glomerular disease, often with associated autoantibody formation. Certain clinical and laboratory features may distinguish these entities from their idiopathic counterparts, and making this distinction is important in the diagnosis and management of these patients. Here, drug-induced, ANCA-associated vasculitis, drug-induced lupus, and drug-associated membranous nephropathy are reviewed. PMID:26092827

  3. Fasciola hepatica tegumental antigens indirectly induce an M2 macrophage-like phenotype in vivo.

    PubMed

    Adams, P N; Aldridge, A; Vukman, K V; Donnelly, S; O'Neill, S M

    2014-10-01

    The M2 subset of macrophages has a critical role to play in host tissue repair, tissue fibrosis and modulation of adaptive immunity during helminth infection. Infection with the helminth, Fasciola hepatica, is associated with M2 macrophages in its mammalian host, and this response is mimicked by its excretory-secretory products (FhES). The tegumental coat of F. hepatica (FhTeg) is another major source of immune-modulatory molecules; we have previously shown that FhTeg can modulate the activity of both dendritic cells and mast cells inhibiting their ability to prime a Th1 immune response. Here, we report that FhTeg does not induce Th2 immune responses but can induce M2-like phenotype in vivo that modulates cytokine production from CD4(+) cells in response to anti-CD3 stimulation. FhTeg induces a RELMα expressing macrophage population in vitro, while in vivo, the expression of Arg1 and Ym-1/2 but not RELMα in FhTeg-stimulated macrophages was STAT6 dependent. To support this finding, FhTeg induces RELMα expression in vivo prior to the induction of IL-13. FhTeg can induce IL-13-producing peritoneal macrophages following intraperitoneal injection This study highlights the important role of FhTeg as an immune-modulatory source during F. hepatica infection and sheds further light on helminth-macrophage interactions. PMID:25039932

  4. The direct and indirect effects of initial job status on midlife psychological distress in Japan: evidence from a mediation analysis

    PubMed Central

    OSHIO, Takashi; INAGAKI, Seiichi

    2015-01-01

    In the current study, we investigated how initial job status at graduation from school is associated with midlife psychological distress, using microdata from a nationwide Internet survey of 3,117 men and 2,818 women aged 30–60 yr. We measured psychological distress using the Kessler 6 (K6) score (range: 0–24) and the binary variable of K6 score ≥5. We found that unstable initial job status substantially raised midlife K6 scores and the probability of a K6 score ≥5 for both men and women. Furthermore, our mediation analysis showed that for men, slightly less than 60% of the effect was mediated by current job status, household income, and marital status. For women, the effect of initial job status was somewhat lesser than that for men, and only 20–30% of it was mediated. Despite these gender asymmetries, the results indicated that initial job status was a key predictor of midlife mental health. The association between job status and mental health should be further investigated with special reference to the institutional attributes of the labor market and their socio-economic/demographic outcomes. PMID:25752251

  5. Experimental Validation of Lightning-Induced Electromagnetic (Indirect) Coupling to Short Monopole Antennas

    SciTech Connect

    Crull, E W; Brown Jr., C G; Perkins, M P; Ong, M M

    2008-07-30

    For short monopoles in this low-power case, it has been shown that a simple circuit model is capable of accurate predictions for the shape and magnitude of the antenna response to lightning-generated electric field coupling effects, provided that the elements of the circuit model have accurate values. Numerical EM simulation can be used to provide more accurate values for the circuit elements than the simple analytical formulas, since the analytical formulas are used outside of their region of validity. However, even with the approximate analytical formulas the simple circuit model produces reasonable results, which would improve if more accurate analytical models were used. This report discusses the coupling analysis approaches taken to understand the interaction between a time-varying EM field and a short monopole antenna, within the context of lightning safety for nuclear weapons at DOE facilities. It describes the validation of a simple circuit model using laboratory study in order to understand the indirect coupling of energy into a part, and the resulting voltage. Results show that in this low-power case, the circuit model predicts peak voltages within approximately 32% using circuit component values obtained from analytical formulas and about 13% using circuit component values obtained from numerical EM simulation. We note that the analytical formulas are used outside of their region of validity. First, the antenna is insulated and not a bare wire and there are perhaps fringing field effects near the termination of the outer conductor that the formula does not take into account. Also, the effective height formula is for a monopole directly over a ground plane, while in the time-domain measurement setup the monopole is elevated above the ground plane by about 1.5-inch (refer to Figure 5).

  6. High plant species diversity indirectly mitigates CO 2- and N-induced effects on grasshopper growth

    NASA Astrophysics Data System (ADS)

    Strengbom, Joachim; Reich, Peter B.; Ritchie, Mark E.

    2008-09-01

    We examined how elevated atmospheric [CO 2] and higher rate of nitrogen (N) input may influence grasshopper growth by changing food plant quality and how such effects may be modified by species diversity of the plant community. We reared grasshopper nymphs ( Melanoplus femurrubrum) on Poa pratensis from field-grown monocultures or polycultures (16 species) that were subjected to either ambient or elevated levels of CO 2 and N. Grasshopper growth rate was higher on P. pratensis leaves grown in monocultures than in polycultures, higher on P. pratensis grown under elevated than under ambient [CO 2], and higher on P. pratensis grown under elevated than under ambient [N]. The higher growth rate observed on P. pratensis exposed to elevated [CO 2] was, however, less pronounced for polyculture- than monoculture-grown P. pratensis. Growth rate of the grasshoppers was positively correlated with leaf [N], [C], and concentration of soluble carbohydrates + lipids. Concentration of non-structural carbohydrates + lipids was higher in leaves grown under elevated than under ambient [CO 2], and the difference between P. pratensis grown under ambient and elevated [CO 2] was greater for monoculture- than polyculture-grown P. pratensis. In addition, leaf N concentration was higher in P. pratensis grown in monocultures than in polycultures, suggesting that plant species richness, indirectly, may influence insect performance by changed nutritional value of the plants. Because we found interactive effects between all factors included ([CO 2], [N], and plant species diversity), our results suggest that these parameters may influence plant-insect interactions in a complex way that is not predictable from the sum of single factor manipulations.

  7. Nitrogen Supply Influences Herbivore-Induced Direct and Indirect Defenses and Transcriptional Responses in Nicotiana attenuata[w

    PubMed Central

    Lou, Yonggen; Baldwin, Ian T.

    2004-01-01

    Although nitrogen (N) availability is known to alter constitutive resistance against herbivores, its influence on herbivore-induced responses, including signaling pathways, transcriptional signatures, and the subsequently elicited chemical defenses is poorly understood. We used the native tobacco, Nicotiana attenuata, which germinates in the postfire environment and copes with large changes in soil N during postfire succession, to compare a suite of Manduca sexta- and elicitor-induced responses in plants grown under high- and low-N (LN) supply rates. LN supply decreased relative growth rates and biomass by 35% at 40 d compared to high-N plants; furthermore, it also attenuated (by 39 and 60%) the elicitor-induced jasmonate and salicylate bursts, two N-intensive direct defenses (nicotine and trypsin proteinase inhibitors, albeit by different mechanisms), and carbon-containing nonvolatile defenses (rutin, chlorogenic acid, and diterpene glycosides), but did not affect the induced release of volatiles (cis-α-bergamotene and germacrene A), which function as indirect defenses. M. sexta and methyl jasmonate-induced transcriptional responses measured with a microarray enriched in herbivore-induced genes were also substantially reduced in plants grown under LN supply rates. In M. sexta-attacked LN plants, only 36 (45%) up-regulated and 46 (58%) down-regulated genes showed the same regulation as those in attacked high-N plants. However, transcriptional responses frequently directly countered the observed metabolic changes. Changes in a leaf's sensitivity to elicitation, an attacked leaf's waning ability to export oxylipin wound signals, and/or resource limitations in LN plants can account for the observed results, underscoring the conclusion that defense activation is a resource-intensive response. PMID:15133153

  8. PRMT6 mediates CSE induced inflammation and apoptosis.

    PubMed

    Kang, Naixing; Chen, Ping; Chen, Yan; Zeng, Huihui; He, Xue; Zhu, Yingqun

    2015-01-01

    Cigarette smoke extract (CSE) induces apoptosis and inflammation, but the mechanism is unknown. Arginine methyltransferase (PRMT6) catalyzes the asymmetric di-methylation of histone H3 arginine 2 (H3R2me2a) to control global level transcription. We hypothesized that PRMT6 mediates CSE induced apoptosis and inflammation through H3R2me2a. The apoptosis after CSE treatment in human umbilical vein endothelial cells (HUVECs) was fully measured with real-time reverse transcription PCR, western blotting and Annexin-V staining. Meanwhile, the inflammation in HUVECs after CSE exposure was detected with real-time reverse transcription PCR, western blotting and ELISA. CSE treatment promoted apoptosis and inflammation in HUVECs, coinciding with the decreased protein abundance of PRMT6. Meanwhile, HUVECs transfected with PRMT6 expressing plasmid inhibited the CSE-induced apoptosis and inflammation. Also, the inhibition of PRMT6 promoted the apoptosis and inflammation in HUVECs induced by CSE. Notably, H3R2me2a was associated with the modulation of PRMT6 in CSE induced apoptosis and inflammation in HUVECs. In conclusion, PRMT6 mediates CSE induced apoptosis and inflammation through H3R2me2a in HUVECs. PMID:25481537

  9. Biomolecular Damage Induced by Ionizing Radiation: The Direct and Indirect Effects of Low-Energy Electrons on DNA

    NASA Astrophysics Data System (ADS)

    Alizadeh, Elahe; Orlando, Thomas M.; Sanche, Léon

    2015-04-01

    Many experimental and theoretical advances have recently allowed the study of direct and indirect effects of low-energy electrons (LEEs) on DNA damage. In an effort to explain how LEEs damage the human genome, researchers have focused efforts on LEE interactions with bacterial plasmids, DNA bases, sugar analogs, phosphate groups, and longer DNA moieties. Here, we summarize the current understanding of the fundamental mechanisms involved in LEE-induced damage of DNA and complex biomolecule films. Results obtained by several laboratories on films prepared and analyzed by different methods and irradiated with different electron-beam current densities and fluencies are presented. Despite varied conditions (e.g., film thicknesses and morphologies, intrinsic water content, substrate interactions, and extrinsic atmospheric compositions), comparisons show a striking resemblance in the types of damage produced and their yield functions. The potential of controlling this damage using molecular and nanoparticle targets with high LEE yields in targeted radiation-based cancer therapies is also discussed.

  10. Plant microtubules reorganization under the indirect UV-B exposure and during UV-B-induced programmed cell death

    PubMed Central

    Krasylenko, Yuliya A.; Yemets, Alla I.; Blume, Yaroslav B.

    2013-01-01

    The role of microtubules in cellular pathways of UV-B signaling in plants as well as in related structural cell response become into focus of few last publications. As microtubules in plant cell reorient/reorganize (become randomized, fragmented or depolymerized) in a response to direct UV-B exposure, these cytoskeletal components could be involved into UV-B signaling pathways as highly responsive players. In the current addendum, indirect UV-B-induced microtubules reorganization in cells of shielded Arabidopsis thaliana (GFP-MAP4) primary roots and the correspondence of microtubules depolymerization with the typical hallmarks of the programmed cell death in Nicotiana tabacum BY-2 (GFP-MBD) cells are discussed. PMID:23438586

  11. Direct and indirect effects of sociocultural influences on disordered eating among Malaysian male and female university students. A mediation analysis of psychological distress.

    PubMed

    Gan, Wan Ying; Mohd Nasir, Mohd Taib; Zalilah, Mohd Shariff; Hazizi, Abu Saad

    2011-06-01

    This study aimed to examine the role of psychological distress in the relationships between sociocultural influences (social pressure to be thin and weight teasing) and disordered eating. Data were collected from 584 university students (59.4% females and 40.6% males), aged 18-24 years old (M=20.6, SD=1.4), selected from four universities in the Klang Valley, Malaysia. Participants completed four standardized questionnaires which measured social pressure to be thin, weight-related teasing, psychological distress and disordered eating. A good fit structural equation modeling (SEM) model was developed for both sexes. For males, the SEM model revealed that sociocultural influences showed an indirect effect on disordered eating through psychological distress. For females, the model showed an indirect effect of sociocultural influences on disordered eating through psychological distress, as well as a direct effect of sociocultural influences on disordered eating. In conclusion, psychological distress mediated the relationships between sociocultural influences and disordered eating in both males and females. Our results suggest that disordered eating intervention programs on reducing psychological distress in university students may be beneficial. PMID:21435366

  12. Agrobacterium tumefaciens-mediated transgenic plant and somaclone production through direct and indirect regeneration from leaves in Stevia rebaudiana with their glycoside profile.

    PubMed

    Khan, Shamshad Ahmad; Ur Rahman, Laiq; Shanker, Karuna; Singh, Manju

    2014-05-01

    Agrobacterium tumefaciens (EHA-105 harboring pCAMBIA 1304)-mediated transgenic plant production via direct regeneration from leaf and elite somaclones generation through indirect regeneration in Stevia rebaudiana is reported. Optimum direct regeneration frequency along with highest transformation frequency was found on MS + 1 mg/l BAP + 1 mg/l NAA, while indirect regeneration from callus was obtained on MS + 1 mg/l BAP + 2 mg/l NAA. Successful transfer of GUS-positive (GUS assay and PCR-based confirmation) transgenic as well as four somaclones up to glasshouse acclimatization has been achieved. Inter-simple sequence repeat (ISSR) profiling of transgenic and somaclonal plants showed a total of 113 bands, out of which 49 were monomorphic (43.36 %) and 64 were polymorphic (56.64 %). Transgenic plant was found to be closer to mother plant, while on the basis of steviol, stevioside, and rebaudioside A profile, somaclone S2 was found to be the best and showed maximum variability in ISSR profiling. PMID:24154495

  13. Intracellular calcium affects prestin's voltage operating point indirectly via turgor-induced membrane tension

    NASA Astrophysics Data System (ADS)

    Song, Lei; Santos-Sacchi, Joseph

    2015-12-01

    Recent identification of a calmodulin binding site within prestin's C-terminus indicates that calcium can significantly alter prestin's operating voltage range as gauged by the Boltzmann parameter Vh (Keller et al., J. Neuroscience, 2014). We reasoned that those experiments may have identified the molecular substrate for the protein's tension sensitivity. In an effort to understand how this may happen, we evaluated the effects of turgor pressure on such shifts produced by calcium. We find that the shifts are induced by calcium's ability to reduce turgor pressure during whole cell voltage clamp recording. Clamping turgor pressure to 1kPa, the cell's normal intracellular pressure, completely counters the calcium effect. Furthermore, following unrestrained shifts, collapsing the cells abolishes induced shifts. We conclude that calcium does not work by direct action on prestin's conformational state. The possibility remains that calcium interaction with prestin alters water movements within the cell, possibly via its anion transport function.

  14. UVA-induced damage to DNA and proteins: direct versus indirect photochemical processes

    NASA Astrophysics Data System (ADS)

    Girard, P. M.; Francesconi, S.; Pozzebon, M.; Graindorge, D.; Rochette, P.; Drouin, R.; Sage, E.

    2011-01-01

    UVA has long been known for generating an oxidative stress in cells. In this paper we review the different types of DNA damage induced by UVA, i.e. strand breaks, bipyrimidine photoproducts, and oxidatively damaged bases. Emphasis is given to the mechanism of formation that is further illustrated by the presentation of new in vitro data. Examples of oxidation of proteins involved in DNA metabolism are also given.

  15. Characteristics of indirect laser-induced plasma from a thin film of oil on a metallic substrate

    NASA Astrophysics Data System (ADS)

    Xiu, Jun-Shan; Bai, Xue-Shi; Motto-Ros, Vincent; Yu, Jin

    2015-04-01

    Optical emissions from the major and trace elements embodied in a transparent gel prepared from cooking oil were detected after the gel was spread in a thin film on a metallic substrate. Such emissions are due to the indirect breakdown of the coating layer. The generated plasma, a mixture of substances from the substrate, the layer, and the ambient gas, was characterized using emission spectroscopy. The characteristics of the plasma formed on the metal with and without the coating layer were investigated. The results showed that Al emission induced from the aluminum substrates coated with oil films extends away from the target surface to ablate the oil film. This finally formed a bifurcating circulation of aluminum vapor against a spherical confinement wall in the front of the plume, which differed from the evolution of the plasma induced from the uncoated aluminum target. The strongest emissions of elements from the oil films can be observed at 2 mm above the target after a detection delay of 1.0 μs. A high temperature zone has been observed in the plasma after the delay of 1.0 μs for the plasma induced from the coated metal. This higher temperature determined in the plasma allows the consideration of the sensitive detection of trace elements in liquids, gels, biological samples, or thin films.

  16. Ammonia Mediates Methamphetamine-Induced Increases in Glutamate and Excitotoxicity

    PubMed Central

    Halpin, Laura E; Northrop, Nicole A; Yamamoto, Bryan K

    2014-01-01

    Ammonia has been identified to have a significant role in the long-term damage to dopamine and serotonin terminals produced by methamphetamine (METH), but how ammonia contributes to this damage is unknown. Experiments were conducted to identify whether increases in brain ammonia affect METH-induced increases in glutamate and subsequent excitotoxicity. Increases in striatal glutamate were measured using in vivo microdialysis. To examine the role of ammonia in mediating changes in extracellular glutamate after METH exposure, lactulose was used to decrease plasma and brain ammonia. Lactulose is a non-absorbable disaccharide, which alters the intestinal lumen through multiple mechanisms that lead to the increased peripheral excretion of ammonia. METH caused a significant increase in extracellular glutamate that was prevented by lactulose. Lactulose had no effect on METH-induced hyperthermia. To determine if ammonia contributed to excitotoxicity, the effect of METH and lactulose treatment on calpain-mediated spectrin proteolysis was measured. METH significantly increased calpain-specific spectrin breakdown products, and this increase was prevented with lactulose treatment. To examine if ammonia-induced increases in extracellular glutamate were mediated by excitatory amino-acid transporters, the reverse dialysis of ammonia, the glutamate transporter inhibitor, DL-threo-β-benzyloxyaspartic acid (TBOA), or the combination of the two directly into the striatum of awake, freely moving rats was conducted. TBOA blocked the increases in extracellular glutamate produced by the reverse dialysis of ammonia. These findings demonstrate that ammonia mediates METH-induced increases in extracellular glutamate through an excitatory amino-acid transporter to cause excitotoxicity. PMID:24165886

  17. Moduli mediation without moduli-induced gravitino problem

    NASA Astrophysics Data System (ADS)

    Akita, Kensuke; Kobayashi, Tatsuo; Oikawa, Akane; Otsuka, Hajime

    2016-05-01

    We study the moduli-induced gravitino problem within the framework of the phenomenologically attractive mirage mediations. The huge amount of gravitino generated by the moduli decay can be successfully diluted by introducing an extra light modulus field which does not induce the supersymmetry breaking. Since the lifetime of extra modulus field becomes longer than usually considered modulus field, our proposed mechanism is applied to both the low- and high-scale supersymmetry breaking scenarios. We also point out that such an extra modulus field appears in the flux compactification of type II string theory.

  18. Sodium selenite-induced hypothermia in mice: indirect evidence for a neural effect.

    PubMed

    Watanabe, C; Suzuki, T

    1986-12-01

    The effect of sodium selenite (SS) on the body temperature of adult male ICR mice was examined. SS (10-60 mumol/kg) administered subcutaneously resulted in a transient and dose-dependent hypothermia at ambient temperatures (Ta) of 20 and 30 degrees C. Reduced oxygen consumption accompanied the changes in body temperature. In addition, SS-treated mice exhibited transient cold-seeking behavior in the thermogradient. This SS-induced hypothermia was very similar to those induced by ethanol, tetrahydrocannabinol, triethyltin, sulfolane, and chlordimeform in that these all were transient, dependent on Ta, and not counteracted by behavioral thermoregulation. From these results, involvement of neural afferent or integral pathways is suggested. Further, acute mortality of SS-injected mice was enhanced with the elevation of Ta, as in the case of the chemicals mentioned above. Considering the diverse chemical and pharmacological properties of these chemicals, these results may suggest a possible interrelation between the hypothermic response and the modification of toxicity. PMID:3787631

  19. Nanoparticle-Mediated, Light-Induced Phase Separations.

    PubMed

    Neumann, Oara; Neumann, Albert D; Silva, Edgar; Ayala-Orozco, Ciceron; Tian, Shu; Nordlander, Peter; Halas, Naomi J

    2015-12-01

    Nanoparticles that both absorb and scatter light, when dispersed in a liquid, absorb optical energy and heat a reduced fluid volume due to the combination of multiple scattering and optical absorption. This can induce a localized liquid-vapor phase change within the reduced volume without the requirement of heating the entire fluid. For binary liquid mixtures, this process results in vaporization of the more volatile component of the mixture. When subsequently condensed, these two steps of vaporization and condensation constitute a distillation process mediated by nanoparticles and driven by optical illumination. Because it does not require the heating of a large volume of fluid, this process requires substantially less energy than traditional distillation using thermal sources. We investigated nanoparticle-mediated, light-induced distillation of ethanol-H2O and 1-propanol-H2O mixtures, using Au-SiO2 nanoshells as the absorber-scatterer nanoparticle and nanoparticle-resonant laser irradiation to drive the process. For ethanol-H2O mixtures, the mole fraction of ethanol obtained in the light-induced process is substantially higher than that obtained by conventional thermal distillation, essentially removing the ethanol-H2O azeotrope that limits conventional distillation. In contrast, for 1-propanol-H2O mixtures the distillate properties resulting from light-induced distillation were very similar to those obtained by thermal distillation. In the 1-propanol-H2O system, a nanoparticle-mediated, light-induced liquid-liquid phase separation was also observed. PMID:26535465

  20. Indirect determination of the electric field in plasma discharges using laser-induced fluorescence spectroscopy

    SciTech Connect

    Vaudolon, J. Mazouffre, S.

    2014-09-15

    The evaluation of electric fields is of prime interest for the description of plasma characteristics. In this work, different methods for determining the electric field profile in low-pressure discharges using one- and two-dimensional Laser-Induced Fluorescence (LIF) measurements are presented and discussed. The energy conservation, fluid, and kinetic approaches appear to be well-suited for the electric field evaluation in this region of the plasma flow. However, the numerical complexity of a two-dimensional kinetic model is penalizing due to the limited signal-to-noise ratio that can be achieved, making the computation of the electric field subject to large error bars. The ionization contribution which appears in the fluid model makes it unattractive on an experimental viewpoint. The energy conservation and 1D1V kinetic approaches should therefore be preferred for the determination of the electric field when LIF data are used.

  1. Multiple direct and indirect mechanisms drive estrogen-induced tumor growth in high grade serous ovarian cancers

    PubMed Central

    Ciucci, Alessandra; Zannoni, Gian Franco; Buttarelli, Marianna; Lisi, Lucia; Travaglia, Daniele; Martinelli, Enrica; Scambia, Giovanni; Gallo, Daniela

    2016-01-01

    The notion that menopausal estrogen replacement therapy increases ovarian cancer risk, but only for the two more common types (i.e. serous and endometrioid), while possibly decreasing risk for clear cell tumors, is strongly suggestive of causality. However, whether estradiol (E2) is tumorigenic or promotes development of occult preexisting disease is unknown. The present study investigated molecular and cellular mechanisms by which E2 modulates the growth of high grade serous ovarian cancer (HGSOC). Results showed that ERα expression was necessary and sufficient to induce the growth of HGSOC cells in in vitro models. Conversely, in vivo experimental studies demonstrated that increasing the levels of circulating estrogens resulted in a significant growth acceleration of ERα-negative HGSOC xenografts, as well. Tumors from E2-treated mice had significantly higher proliferation rate, angiogenesis, and density of tumor-associated macrophage (TAM) compared to ovariectomized females. Accordingly, immunohistochemical analysis of ERα-negative tissue specimens from HGSOC patients showed a significantly greater TAM infiltration in premenopausal compared to postmenopausal women. This study describes novel insights into the impact of E2 on tumor microenvironment, independently of its direct effect on tumor cell growth, thus supporting the idea that multiple direct and indirect mechanisms drive estrogen-induced tumor growth in HGSOC. PMID:26797759

  2. Structural insights into triglyceride storage mediated by fat storage-inducing transmembrane (FIT) protein 2.

    PubMed

    Gross, David A; Snapp, Erik L; Silver, David L

    2010-01-01

    Fat storage-Inducing Transmembrane proteins 1 & 2 (FIT1/FITM1 and FIT2/FITM2) belong to a unique family of evolutionarily conserved proteins localized to the endoplasmic reticulum that are involved in triglyceride lipid droplet formation. FIT proteins have been shown to mediate the partitioning of cellular triglyceride into lipid droplets, but not triglyceride biosynthesis. FIT proteins do not share primary sequence homology with known proteins and no structural information is available to inform on the mechanism by which FIT proteins function. Here, we present the experimentally-solved topological models for FIT1 and FIT2 using N-glycosylation site mapping and indirect immunofluorescence techniques. These methods indicate that both proteins have six-transmembrane-domains with both N- and C-termini localized to the cytosol. Utilizing this model for structure-function analysis, we identified and characterized a gain-of-function mutant of FIT2 (FLL(157-9)AAA) in transmembrane domain 4 that markedly augmented the total number and mean size of lipid droplets. Using limited-trypsin proteolysis we determined that the FLL(157-9)AAA mutant has enhanced trypsin cleavage at K86 relative to wild-type FIT2, indicating a conformational change. Taken together, these studies indicate that FIT2 is a 6 transmembrane domain-containing protein whose conformation likely regulates its activity in mediating lipid droplet formation. PMID:20520733

  3. IL-4 mediates dicloxacillin-induced liver injury in mice.

    PubMed

    Higuchi, Satonori; Kobayashi, Masanori; Yoshikawa, Yukitaka; Tsuneyama, Koichi; Fukami, Tatsuki; Nakajima, Miki; Yokoi, Tsuyoshi

    2011-02-01

    Drug-induced liver injury (DILI) is a major problem in drug development and clinical drug therapy. In most cases, the mechanisms are still unknown. It is difficult to predict DILI in humans due to the lack of experimental animal models. Dicloxacillin, penicillinase-sensitive penicillin, rarely causes cholestatic or mixed liver injury, and there is some evidence for immunoallergic idiosyncratic reaction in human. In this study, we investigated the mechanisms of dicloxacillin-induced liver injury. Plasma ALT and total-bilirubin (T-Bil) levels were significantly increased in dicloxacillin-administered (600 mg/kg, i.p.) mice. Dicloxacillin administration induced Th2 (helper T cells)-mediated factors and increased the plasma interleukin (IL)-4 level. Neutralization of IL-4 suppressed the hepatotoxicity of dicloxacillin, and recombinant mouse IL-4 administration (0.5 or 2.0 μg/mouse, i.p.) exacerbated it. Chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTh2) is a cognate receptor for prostaglandin (PG) D(2), and is suggested to be involved in Th2-dependent allergic inflammation. We investigated the effect of 13,14-Dihydro-15-keto-PGD(2) (DK-PGD(2); 10 μg/mouse, i.p.) administration on dicloxacillin-induced liver injury. DK-PGD(2)/dicloxacillin coadministration resulted in a significant increase of alanine aminotransferases and a remarkable increase of macrophage inflammatory protein 2 expression. In conclusion, to the best of our knowledge, this is the first report to demonstrate that dicloxacillin-induced liver injury is mediated by a Th2-type immune reaction and exacerbated by DK-PGD(2). PMID:21094227

  4. Akt and MAPK signaling mediate pregnancy-induced cardiac adaptation.

    PubMed

    Chung, Eunhee; Yeung, Fan; Leinwand, Leslie A

    2012-05-01

    Although the signaling pathways underlying exercise-induced cardiac adaptation have been extensively studied, little is known about the molecular mechanisms that result in the response of the heart to pregnancy. The objective of this study was to define the morphological, functional, and gene expression patterns that define the hearts of pregnant mice, and to identify the signaling pathways that mediate this response. Mice were divided into three groups: nonpregnant diestrus control, midpregnancy, and late pregnancy. Both time points of pregnancy were associated with significant cardiac hypertrophy. The prosurvival signaling cascades of Akt and ERK1/2 were activated in the hearts of pregnant mice, while the stress kinase, p38, was decreased. Given the activation of Akt in pregnancy and its known role in cardiac hypertrophy, the hypertrophic response to pregnancy was tested in mice expressing a cardiac-specific activated (myristoylated) form of Akt (myrAkt) or a cardiac-specific constitutively active (antipathologic hypertrophic) form of its downstream target, glycogen synthase kinase 3β (caGSK3β). The pregnancy-induced hypertrophic responses of hearts from these mice were significantly attenuated. Finally, we tested whether pregnancy-associated sex hormones could induce hypertrophy and alter signaling pathways in isolated neonatal rat ventricular myocytes (NRVMs). In fact, progesterone, but not estradiol treatment increased NRVM cell size via phosphorylation of ERK1/2. Inhibition of MEK1 effectively blocked progesterone-induced cellular hypertrophy. Taken together, our study demonstrates that pregnancy-induced cardiac hypertrophy is mediated by activation of Akt and ERK1/2 pathways. PMID:22345431

  5. Plant systemic induced responses mediate interactions between root parasitic nematodes and aboveground herbivorous insects

    PubMed Central

    Wondafrash, Mesfin; Van Dam, Nicole M.; Tytgat, Tom O. G.

    2013-01-01

    Insects and nematodes are the most diverse and abundant groups of multicellular animals feeding on plants on either side of the soil–air interface. Several herbivore-induced responses are systemic, and hence can influence the preference and performance of organisms in other plant organs. Recent studies show that plants mediate interactions between belowground plant parasitic nematodes (PPNs) and aboveground herbivorous insects. Based on the knowledge of plant responses to pathogens, we review the emerging insights on plant systemic responses against root-feeding nematodes and shoot-feeding insects. We discuss the potential mechanisms of plant-mediated indirect interactions between both groups of organisms and point to gaps in our knowledge. Root-feeding nematodes can positively or negatively affect shoot herbivorous insects, and vice versa. The outcomes of the interactions between these spatially separated herbivore communities appear to be influenced by the feeding strategy of the nematodes and the insects, as well as by host plant susceptibility to both herbivores. The potential mechanisms for these interactions include systemic induced plant defense, interference with the translocation and dynamics of locally induced secondary metabolites, and reallocation of plant nutritional reserves. During evolution, PPNs as well as herbivorous insects have acquired effectors that modify plant defense responses and resource allocation patterns to their advantage. However, it is also known that plants under herbivore attack change the allocation of their resources, e.g., for compensatory growth responses, which may affect the performance of other organisms feeding on the plant. Studying the chemical and molecular basis of these interactions will reveal the molecular mechanisms that are involved. Moreover, it will lead to a better understanding of the ecological relevance of aboveground–belowground interactions, as well as support the development of sustainable pest

  6. Plant systemic induced responses mediate interactions between root parasitic nematodes and aboveground herbivorous insects.

    PubMed

    Wondafrash, Mesfin; Van Dam, Nicole M; Tytgat, Tom O G

    2013-01-01

    Insects and nematodes are the most diverse and abundant groups of multicellular animals feeding on plants on either side of the soil-air interface. Several herbivore-induced responses are systemic, and hence can influence the preference and performance of organisms in other plant organs. Recent studies show that plants mediate interactions between belowground plant parasitic nematodes (PPNs) and aboveground herbivorous insects. Based on the knowledge of plant responses to pathogens, we review the emerging insights on plant systemic responses against root-feeding nematodes and shoot-feeding insects. We discuss the potential mechanisms of plant-mediated indirect interactions between both groups of organisms and point to gaps in our knowledge. Root-feeding nematodes can positively or negatively affect shoot herbivorous insects, and vice versa. The outcomes of the interactions between these spatially separated herbivore communities appear to be influenced by the feeding strategy of the nematodes and the insects, as well as by host plant susceptibility to both herbivores. The potential mechanisms for these interactions include systemic induced plant defense, interference with the translocation and dynamics of locally induced secondary metabolites, and reallocation of plant nutritional reserves. During evolution, PPNs as well as herbivorous insects have acquired effectors that modify plant defense responses and resource allocation patterns to their advantage. However, it is also known that plants under herbivore attack change the allocation of their resources, e.g., for compensatory growth responses, which may affect the performance of other organisms feeding on the plant. Studying the chemical and molecular basis of these interactions will reveal the molecular mechanisms that are involved. Moreover, it will lead to a better understanding of the ecological relevance of aboveground-belowground interactions, as well as support the development of sustainable pest management

  7. Defect-mediated discrete solitons in optically induced photorefractive lattices

    SciTech Connect

    Li Yongyao; Pang Wei; Chen Yongzhu; Yu Zhiqiang; Zhou Jianying; Zhang Huarong

    2009-10-15

    Theoretical analysis to the defect mediated discrete solitons in one- and two-dimensional periodical waveguide lattices is presented. The waveguide arrays with these functional defects are assumed to respond to the light field as an optically induced photorefraction and they are patterned by a holographic technique. It is found that the spatial energy distributions of the solitary waves can be controlled by the defects in the waveguide arrays, and this gives rise to an additional freedom to externally shaping the light field distribution to a special shape.

  8. Cystamine induces AIF-mediated apoptosis through glutathione depletion.

    PubMed

    Cho, Sung-Yup; Lee, Jin-Haeng; Ju, Mi-kyeong; Jeong, Eui Man; Kim, Hyo-Jun; Lim, Jisun; Lee, Seungun; Cho, Nam-Hyuk; Park, Hyun Ho; Choi, Kihang; Jeon, Ju-Hong; Kim, In-Gyu

    2015-03-01

    Cystamine and its reduced form cysteamine showed protective effects in various models of neurodegenerative disease, including Huntington's disease and Parkinson's disease. Other lines of evidence demonstrated the cytotoxic effect of cysteamine on duodenal mucosa leading to ulcer development. However, the mechanism for cystamine cytotoxicity remains poorly understood. Here, we report a new pathway in which cystamine induces apoptosis by targeting apoptosis-inducing factor (AIF). By screening of various cell lines, we observed that cystamine and cysteamine induce cell death in a cell type-specific manner. Comparison between cystamine-sensitive and cystamine-resistant cell lines revealed that cystamine cytotoxicity is not associated with unfolded protein response, reactive oxygen species generation and transglutaminase or caspase activity; rather, it is associated with the ability of cystamine to trigger AIF nuclear translocation. In cystamine-sensitive cells, cystamine suppresses the levels of intracellular glutathione by inhibiting γ-glutamylcysteine synthetase expression that triggers AIF translocation. Conversely, glutathione supplementation completely prevents cystamine-induced AIF translocation and apoptosis. In rats, cysteamine administration induces glutathione depletion and AIF translocation leading to apoptosis of duodenal epithelium. These results indicate that AIF translocation through glutathione depletion is the molecular mechanism of cystamine toxicity, and provide important implications for cystamine in the neurodegenerative disease therapeutics as well as in the regulation of AIF-mediated cell death. PMID:25549939

  9. Sphingosine kinase-1 mediates androgen-induced osteoblast cell growth.

    PubMed

    Martin, Claire; Lafosse, Jean-Michel; Malavaud, Bernard; Cuvillier, Olivier

    2010-01-01

    Herein we report that the lipid kinase sphingosine kinase-1 (SphK1) is instrumental in mediating androgen-induced cell proliferation in osteoblasts. Dihydrotestosterone (DHT) triggered cell growth in steroid-deprived MC3T3 cells, which was associated with a rapid stimulation of SphK1 and activation of both Akt and ERK signaling pathways. This mechanism relied on functional androgen receptor/PI3K/Akt nongenotropic signaling as pharmacological antagonists could block SphK1 stimulation by DHT and its consequences. Finally, SphK1 inhibition not only abrogated DHT-induced ERK activation but also blocked cell proliferation, while ERK inhibition had no impact, suggesting that SphK1 was critical for DHT signaling yet independently of the ERK. PMID:19932089

  10. Sphingosine kinase-1 mediates androgen-induced osteoblast cell growth

    SciTech Connect

    Martin, Claire; Lafosse, Jean-Michel; Malavaud, Bernard; Cuvillier, Olivier

    2010-01-01

    Herein we report that the lipid kinase sphingosine kinase-1 (SphK1) is instrumental in mediating androgen-induced cell proliferation in osteoblasts. Dihydrotestosterone (DHT) triggered cell growth in steroid-deprived MC3T3 cells, which was associated with a rapid stimulation of SphK1 and activation of both Akt and ERK signaling pathways. This mechanism relied on functional androgen receptor/PI3K/Akt nongenotropic signaling as pharmacological antagonists could block SphK1 stimulation by DHT and its consequences. Finally, SphK1 inhibition not only abrogated DHT-induced ERK activation but also blocked cell proliferation, while ERK inhibition had no impact, suggesting that SphK1 was critical for DHT signaling yet independently of the ERK.

  11. Tumors Escape CD4+ T-cell-Mediated Immunosurveillance by Impairing the Ability of Infiltrating Macrophages to Indirectly Present Tumor Antigens.

    PubMed

    Tveita, Anders Aune; Schjesvold, Fredrik; Haabeth, Ole Audun; Fauskanger, Marte; Bogen, Bjarne

    2015-08-15

    Tumors cells can escape cytotoxic CD8+ T cells by preventing MHC I display of tumor antigens. It is unknown how tumors evade CD4+ T-cell responses, but because many tumor cells lack MHC II expression, novel mechanisms would be required. We have investigated this issue in a model in which MHC II(NEG) myeloma cells secrete a monoclonal Ig containing a V region L chain (VL) epitope recognized by CD4+ T cells. Infiltrating macrophages process and present the secreted tumor antigen to Th1 cells, resulting in induction of macrophage cytotoxicity and apparent rejection of the tumor. Despite long-term tumor protection in VL-specific T-cell receptor transgenic mice, we here describe that some myeloma cells persisted in a dormant state and, eventually, formed expanding tumors. Escape tumor cells maintained their secretion of complete (H+L) monoclonal Ig with unchanged sequence, while secretion of surplus free L chain was severely diminished. Although free L chains were efficiently processed and presented by tumor-infiltrating macrophages to CD4+ T cells, complete (H+L) monoclonal Ig was not. Forced overexpression of free L chain secretion reinstated tumor rejection. These results show that tumors can escape CD4+ T-cell-mediated rejection by impairing indirect presentation of tumor antigen by infiltrating macrophages. This occurs through a novel mechanism of immunoediting, in which modulation of the quaternary structure of the secreted tumor-specific antigen reduces its immunogenicity. PMID:26038231

  12. Granzyme B mediates both direct and indirect cleavage of extracellular matrix in skin after chronic low-dose ultraviolet light irradiation

    PubMed Central

    Parkinson, Leigh G; Toro, Ana; Zhao, Hongyan; Brown, Keddie; Tebbutt, Scott J; Granville, David J

    2015-01-01

    Extracellular matrix (ECM) degradation is a hallmark of many chronic inflammatory diseases that can lead to a loss of function, aging, and disease progression. Ultraviolet light (UV) irradiation from the sun is widely considered as the major cause of visible human skin aging, causing increased inflammation and enhanced ECM degradation. Granzyme B (GzmB), a serine protease that is expressed by a variety of cells, accumulates in the extracellular milieu during chronic inflammation and cleaves a number of ECM proteins. We hypothesized that GzmB contributes to ECM degradation in the skin after UV irradiation through both direct cleavage of ECM proteins and indirectly through the induction of other proteinases. Wild-type and GzmB-knockout mice were repeatedly exposed to minimal erythemal doses of solar-simulated UV irradiation for 20 weeks. GzmB expression was significantly increased in wild-type treated skin compared to nonirradiated controls, colocalizing to keratinocytes and to an increased mast cell population. GzmB deficiency significantly protected against the formation of wrinkles and the loss of dermal collagen density, which was related to the cleavage of decorin, an abundant proteoglycan involved in collagen fibrillogenesis and integrity. GzmB also cleaved fibronectin, and GzmB-mediated fibronectin fragments increased the expression of collagen-degrading matrix metalloproteinase-1 (MMP-1) in fibroblasts. Collectively, these findings indicate a significant role for GzmB in ECM degradation that may have implications in many age-related chronic inflammatory diseases. PMID:25495009

  13. Immune-mediated drug-induced liver disease.

    PubMed

    Liu, Zhang-Xu; Kaplowitz, Neil

    2002-08-01

    Drug-induced immune-mediated hepatic injury is an adverse immune response against the liver that results in a disease with hepatitic, cholestatic, or mixed clinical features. Drugs such as halothane, tienilic acid, dihydralazine, and anticonvulsants trigger a hepatitic reaction, and drugs such as chlorpromazine, erythromycins, amoxicillin-calvulanic acid, sulfonamides and sulindac trigger a cholestatic or mixed reaction. Unstable metabolites derived from the metabolism of the drug may bind to cellular proteins or macromolecules, leading to a direct toxic effect on hepatocytes. Protein adducts formed in the metabolism of the drug may be recognized by the immune system as neoantigens. Immunocyte activation may then generate autoantibodies and cell-mediated immune responses, which in turn damage the hepatocytes. Cytochromes 450 are the major oxidative catalysts in drug metabolism, and they can form a neoantigen by covalently binding with the drug metabolite that they produce. Autoantibodies that develop are selectively directed against the particular cytochrome isoenzyme that metabolized the parent drug. The hapten hypothesis proposes that the drug metabolite can act as a hapten and can modify the self of the individual by covalently binding to proteins. The danger hypothesis proposes that the immune system only responds to a foreign antigen if the antigen is associated with a danger signal, such as cell stress or cell death. Most clinically overt adverse hepatic events associated with drugs are unpredictable, and they have intermediate (1 to 8 weeks) or long latency (up to 12 months) periods characteristic of hypersensitivity reactions. Immune-mediated drug-induced liver disease nearly always disappears or becomes quiescent when the drug is removed. Methyldopa, minocycline, and nitrofurantoin can produce a chronic hepatitis resembling AIH if the drug is continued. PMID:12362579

  14. Evidence for an indirect effect of radiation on mammalian chromosomes. III. UV- and x-ray-induced sister chromatid exchanges in heterokaryons

    SciTech Connect

    Graves, J.A.; Kellow, G.N.

    1983-04-01

    The hypothesis that chromosomes may be damaged indirectly by radiation was examined by assaying sister chromatid exchange, (SCE) frequency in heterokaryons between irradiated and unirradiated mouse and Chinese hamster cells. One cell line was UV or x irradiated, then fused to unirradiated BrdU-labeled cells of the other line; SCEs in the unirradiated set were scored in heterokaryons. A dose-dependent increase was consistently observed; the magnitude of which suggested that 25% of UV-induced and up to 60% of x-ray-induced SCEs are indirectly induced. Medium transfer experiments, cell mixing, and fusion with irradiated chick erythrocyte ghosts suggested that unirradiated chromosomes in heterokaryons are damaged by a stable, nondiffusible cytoplasmic component contributed by the irradiated cell.

  15. Atrial natriuretic peptide mediates oxytocin secretion induced by osmotic stimulus.

    PubMed

    Chriguer, Rosengela S; Antunes-Rodrigues, José; Franci, Celso R

    2003-02-15

    Atrial natriuretic peptide (ANP), first discovered in the heart, has been also detected in various brain regions involved in the control of cardiovascular function and water and sodium balance. The anteroventral region of the third ventricle (AV3V) and the subfornical organ (SFO) have ANP-immunoreactive projections towards the paraventricular (PVN) and supraoptic (SON) nuclei of the hypothalamus. Extracellular fluid (ECF) hyperosmolality stimulates the secretion of oxytocin (OT) which induces ANP release by the atrium. On the other hand, passive immunoneutralization of ANP reduces OT secretion in response to ECF hypertonicity. Previous studies have shown the co-localization of ANP and OT in PVN and SON neurons and in the periventricular region, as well as the presence of ANPergic and oxytocinergic neurons in the median eminence. The aim of the present study was to investigate the OT and ANP content in the SON and PVN of the hypothalamus and in the posterior pituitary (PP) after an osmotic stimulus that induces OT secretion. The results showed that intracerebroventricular microinjection of normal rabbit serum (NRS) or of ANP antiserum followed or not by an intraperitoneal injection of isotonic saline did not alter OT secretion or OT content in the PVN, SON, and PP; passive ANP immunoneutralization reduced the basal content of ANP in the PVN, SON, and PP of animals in a situation of isotonicity; the ANP antiserum inhibited the increase of OT secretion and content of OT and ANP in the PVN, SON and PP induced by the osmotic stimulus. Thus, the increase in plasma OT and oxytocinergic neurons of the hypothalamus-posterior pituitary system in response to hypertonicity depends on the action of endogenous ANP, i.e., ECF hypertonicity must activate ANPergic neurons which directly or indirectly stimulate OT release. PMID:12576148

  16. FOXO1 Mediates RANKL Induced Osteoclast Formation and Activity

    PubMed Central

    Wang, Yu; Dong, Guangyu; Jeon, Hyeran Helen; Elazizi, Mohamad; La, Lan B.; Hameedaldeen, Alhassan; Xiao, E; Tian, Chen; Alsadun, Sarah; Choi, Yongwon; Graves, Dana T.

    2015-01-01

    We have previously shown that the transcription factor FOXO1 is elevated in conditions with high levels of bone resorption. To investigate the role of FOXO1 in the formation of osteoclasts we examined mice with lineage specific deletion of FOXO1 in osteoclast precursors and by knockdown of FOXO1 with siRNA. The receptor activator of NF-kappa B ligand (RANKL), a principal bone resorbing factor, induced FOXO1 expression and nuclear localization two days after stimulation in bone marrow macrophages (BMMs) and RAW264.7 osteoclast precursors. RANKL- induced osteoclast formation and osteoclast activity was reduced in half in vivo and in vitro with lineage specific FOXO1 deletion (LyzM.Cre+FOXO1L/L) compared to matched controls (LyzM.Cre−FOXO1L/L). Similar results were obtained by knockdown of FOXO1 in RAW264.7 cells. Moreover, FOXO1-mediated osteoclast formation was linked to regulation of NFATc1 nuclear localization and expression as well as a number of downstream factors including dendritic cell-specific transmembrane protein (DC-STAMP), ATP6vod2, cathepsin K and integrin αν Lastly, FOXO1 deletion reduced M-CSF induced RANK expression and migration of osteoclast precursors. Studies presented here provide the evidence that FOXO1 plays a direct role in osteoclast formation by mediating the effect of RANKL on NFATc1 and several downstream effectors. This is likely to be significant since FOXO1 and RANKL are elevated in osteolytic conditions. PMID:25694609

  17. Disorder-induced enhancement of indirect absorption in a GeSn photodetector grown by molecular beam epitaxy

    NASA Astrophysics Data System (ADS)

    Li, H.; Chang, C.; Cheng, H. H.; Sun, G.; Soref, R. A.

    2016-05-01

    We report an investigation on the absorption mechanism of a GeSn photodetector with 2.4% Sn composition in the active region. Responsivity is measured and absorption coefficient is calculated. Square root of absorption coefficient linearly depends on photon energy indicating an indirect transition. However, the absorption coefficient is found to be at least one order of magnitude higher than that of most other indirect materials, suggesting that the indirect optical absorption transition cannot be assisted only by phonon. Our analysis of absorption measurements by other groups on the same material system showed the values of absorption coefficient on the same order of magnitude. Our study reveals that the strong enhancement of absorption for the indirect optical transition is the result of alloy disorder from the incorporation of the much larger Sn atoms into the Ge lattice that are randomly distributed.

  18. Protein disulfide isomerase mediates glutathione depletion-induced cytotoxicity.

    PubMed

    Okada, Kazushi; Fukui, Masayuki; Zhu, Bao-Ting

    2016-08-26

    Glutathione depletion is a distinct cause underlying many forms of pathogenesis associated with oxidative stress and cytotoxicity. Earlier studies showed that glutamate-induced glutathione depletion in immortalized murine HT22 hippocampal neuronal cells leads to accumulation of reactive oxygen species (ROS) and ultimately cell death, but the precise mechanism underlying these processes is not clear. Here we show that during the induction of glutathione depletion, nitric oxide (NO) accumulation precedes ROS accumulation. While neuronal NO synthase (nNOS) in untreated HT22 cells exists mostly as a monomer, glutathione depletion results in increased formation of the dimer nNOS, accompanied by increases in the catalytic activity. We identified that nNOS dimerization is catalyzed by protein disulfide isomerase (PDI). Inhibition of PDI's isomerase activity effectively abrogates glutathione depletion-induced conversion of monomer nNOS into dimer nNOS, accumulation of NO and ROS, and cytotoxicity. Furthermore, we found that PDI is present in untreated cells in an inactive S-nitrosylated form, which becomes activated following glutathione depletion via S-denitrosylation. These results reveal a novel role for PDI in mediating glutathione depletion-induced oxidative cytotoxicity, as well as its role as a valuable therapeutic target for protection against oxidative cytotoxicity. PMID:27317486

  19. Indirect Imaging

    NASA Astrophysics Data System (ADS)

    Kundu, Mukul R.

    This book is the Proceedings of an International Symposium held in Sydney, Australia, August 30-September 2, 1983. The meeting was sponsored by the International Union of Radio Science and the International Astronomical Union.Indirect imaging is based upon the principle of determining the actual form of brightness distribution in a complex case by Fourier synthesis, using information derived from a large number of Fourier components. The main topic of the symposium was how to get the best images from data obtained from telescopes and other similar imaging instruments. Although the meeting was dominated by radio astronomers, with the consequent dominance of discussion of indirect imaging in the radio domain, there were quite a few participants from other disciplines. Thus there were some excellent discussions on optical imaging and medical imaging.

  20. Extracellular Mutant SOD1 Induces Microglial-Mediated Motoneuron Injury

    PubMed Central

    Zhao, Weihua; Beers, David R.; Henkel, Jenny S.; Zhang, Wei; Urushitani, Makoto; Julien, Jean-Pierre; Appel, Stanley H.

    2009-01-01

    Through undefined mechanisms, dominant mutations in (Cu/Zn) superoxide dismutase-1 (mSOD1) cause the non-cell-autonomous death of motoneurons in inherited amyotrophic lateral sclerosis (ALS). Microgliosis at sites of motoneuron injury is a neuropathological hallmark of ALS. Extracellular mSOD1 causes motoneuron injury and triggers microgliosis in spinal cord cultures, but it is unclear whether the injury results from extracellular mSOD1 directly interacting with motoneurons or is mediated through mSOD1-activated microglia. To dissociate these potential mSOD1-mediated neurotoxic mechanisms, the effects of extracellular human mSOD1G93A or mSOD1G85R were assayed using primary cultures of motoneurons and microglia. The data demonstrate that exogenous mSOD1G93A did not cause detectable direct killing of motoneurons. In contrast, mSOD1G93A or mSOD1G85R did induce the morphological and functional activation of microglia, increasing their release of pro-inflammatory cytokines and free radicals. Furthermore, only when microglia were co-cultured with motoneurons did extracellular mSOD1G93A injure motoneurons. The microglial activation mediated by mSOD1G93A was attenuated using toll-like receptors (TLR) 2, TLR4 and CD14 blocking antibodies, or when microglia lacked CD14 expression. These data suggest that extracellular mSOD1G93A is not directly toxic to motoneurons but requires microglial activation for toxicity, utilizing CD14 and TLR pathways. This link between mSOD1 and innate immunity may offer novel therapeutic targets in ALS. PMID:19672969

  1. CFTR mediates noradrenaline-induced ATP efflux from DRG neurons

    PubMed Central

    2011-01-01

    In our earlier study, noradrenaline (NA) stimulated ATP release from dorsal root ganglion (DRG) neurons as mediated via β3 adrenoceptors linked to Gs protein involving protein kinase A (PKA) activation, to cause allodynia. The present study was conducted to understand how ATP is released from DRG neurons. In an outside-out patch-clamp configuration from acutely dissociated rat DRG neurons, single-channel currents, sensitive to the P2X receptor inhibitor PPADS, were evoked by approaching the patch-electrode tip close to a neuron, indicating that ATP is released from DRG neurons, to activate P2X receptor. NA increased the frequency of the single-channel events, but such NA effect was not found for DRG neurons transfected with the siRNA to silence the cystic fibrosis transmembrane conductance regulator (CFTR) gene. In the immunocytochemical study using acutely dissociated rat DRG cells, CFTR was expressed in neurons alone, but not satellite cells, fibroblasts, or Schwann cells. It is concluded from these results that CFTR mediates NA-induced ATP efflux from DRG neurons as an ATP channel. PMID:21943397

  2. TRPV3 channels mediate strontium-induced mouse egg activation

    PubMed Central

    Carvacho, Ingrid; Lee, Hoi Chang; Fissore, Rafael A.; Clapham, David E.

    2014-01-01

    SUMMARY In mammals, calcium influx is required for oocyte maturation and egg activation. The molecular identities of the calcium-permeant channels that underlie the initiation of embryonic development are not established. Here, we describe a Transient Receptor Potential (TRP) ion channel current activated by TRP agonists that is absent in TrpV3−/− eggs. TRPV3 current is differentially expressed during oocyte maturation, reaching a peak of maximum density and activity at metaphase of meiosis II (MII), the stage of fertilization. Selective activation of TRPV3 channels provokes egg activation by mediating massive calcium entry. Widely used to activate eggs, strontium application is known to yield normal offspring in combination with somatic cell nuclear transfer. We show that TRPV3 is required for strontium influx, as TrpV3−/− eggs failed to permeate Sr2+ or undergo strontium-induced activation. We propose that TRPV3 is the major mediator of calcium influx in mouse eggs and is a putative target for artificial egg activation. PMID:24316078

  3. Snail1 Mediates Hypoxia-Induced Melanoma Progression

    PubMed Central

    Liu, Shujing; Kumar, Suresh M.; Martin, James S.; Yang, Ruifeng; Xu, Xiaowei

    2011-01-01

    Tumor hypoxia is a known adverse prognostic factor, and the hypoxic dermal microenvironment participates in melanomagenesis. High levels of hypoxia inducible factor (HIF) expression in melanoma cells, particularly HIF-2α, is associated with poor prognosis. The mechanism underlying the effect of hypoxia on melanoma progression, however, is not fully understood. We report evidence that the effects of hypoxia on melanoma cells are mediated through activation of Snail1. Hypoxia increased melanoma cell migration and drug resistance, and these changes were accompanied by increased Snail1 and decreased E-cadherin expression. Snail1 expression was regulated by HIF-2α in melanoma. Snail1 overexpression led to more aggressive tumor phenotypes and features associated with stem-like melanoma cells in vitro and increased metastatic capacity in vivo. In addition, we found that knockdown of endogenous Snail1 reduced melanoma proliferation and migratory capacity. Snail1 knockdown also prevented melanoma metastasis in vivo. In summary, hypoxia up-regulates Snail1 expression and leads to increased metastatic capacity and drug resistance in melanoma cells. Our findings support that the effects of hypoxia on melanoma are mediated through Snail1 gene activation and suggest that Snail1 is a potential therapeutic target for the treatment of melanoma. PMID:21996677

  4. Tip60 HAT Action Mediates Environmental Enrichment Induced Cognitive Restoration.

    PubMed

    Xu, Songjun; Panikker, Priyalakshmi; Iqbal, Sahira; Elefant, Felice

    2016-01-01

    Environmental enrichment (EE) conditions have beneficial effects for reinstating cognitive ability in neuropathological disorders like Alzheimer's disease (AD). While EE benefits involve epigenetic gene control mechanisms that comprise histone acetylation, the histone acetyltransferases (HATs) involved remain largely unknown. Here, we examine a role for Tip60 HAT action in mediating activity- dependent beneficial neuroadaptations to EE using the Drosophila CNS mushroom body (MB) as a well-characterized cognition model. We show that flies raised under EE conditions display enhanced MB axonal outgrowth, synaptic marker protein production, histone acetylation induction and transcriptional activation of cognition linked genes when compared to their genotypically identical siblings raised under isolated conditions. Further, these beneficial changes are impaired in both Tip60 HAT mutant flies and APP neurodegenerative flies. While EE conditions provide some beneficial neuroadaptive changes in the APP neurodegenerative fly MB, such positive changes are significantly enhanced by increasing MB Tip60 HAT levels. Our results implicate Tip60 as a critical mediator of EE-induced benefits, and provide broad insights into synergistic behavioral and epigenetic based therapeutic approaches for treatment of cognitive disorder. PMID:27454757

  5. Tip60 HAT Action Mediates Environmental Enrichment Induced Cognitive Restoration

    PubMed Central

    Xu, Songjun; Panikker, Priyalakshmi; Iqbal, Sahira; Elefant, Felice

    2016-01-01

    Environmental enrichment (EE) conditions have beneficial effects for reinstating cognitive ability in neuropathological disorders like Alzheimer’s disease (AD). While EE benefits involve epigenetic gene control mechanisms that comprise histone acetylation, the histone acetyltransferases (HATs) involved remain largely unknown. Here, we examine a role for Tip60 HAT action in mediating activity- dependent beneficial neuroadaptations to EE using the Drosophila CNS mushroom body (MB) as a well-characterized cognition model. We show that flies raised under EE conditions display enhanced MB axonal outgrowth, synaptic marker protein production, histone acetylation induction and transcriptional activation of cognition linked genes when compared to their genotypically identical siblings raised under isolated conditions. Further, these beneficial changes are impaired in both Tip60 HAT mutant flies and APP neurodegenerative flies. While EE conditions provide some beneficial neuroadaptive changes in the APP neurodegenerative fly MB, such positive changes are significantly enhanced by increasing MB Tip60 HAT levels. Our results implicate Tip60 as a critical mediator of EE-induced benefits, and provide broad insights into synergistic behavioral and epigenetic based therapeutic approaches for treatment of cognitive disorder. PMID:27454757

  6. Nitric oxide mediates glial-induced neurodegeneration in Alexander disease.

    PubMed

    Wang, Liqun; Hagemann, Tracy L; Kalwa, Hermann; Michel, Thomas; Messing, Albee; Feany, Mel B

    2015-01-01

    Glia play critical roles in maintaining the structure and function of the nervous system; however, the specific contribution that astroglia make to neurodegeneration in human disease states remains largely undefined. Here we use Alexander disease, a serious degenerative neurological disorder caused by astrocyte dysfunction, to identify glial-derived NO as a signalling molecule triggering astrocyte-mediated neuronal degeneration. We further find that NO acts through cGMP signalling in neurons to promote cell death. Glial cells themselves also degenerate, via the DNA damage response and p53. Our findings thus define a specific mechanism for glial-induced non-cell autonomous neuronal cell death, and identify a potential therapeutic target for reducing cellular toxicity in Alexander disease, and possibly other neurodegenerative disorders with glial dysfunction. PMID:26608817

  7. Nitric oxide mediates glial-induced neurodegeneration in Alexander disease

    PubMed Central

    Wang, Liqun; Hagemann, Tracy L.; Kalwa, Hermann; Michel, Thomas; Messing, Albee; Feany, Mel B.

    2015-01-01

    Glia play critical roles in maintaining the structure and function of the nervous system; however, the specific contribution that astroglia make to neurodegeneration in human disease states remains largely undefined. Here we use Alexander disease, a serious degenerative neurological disorder caused by astrocyte dysfunction, to identify glial-derived NO as a signalling molecule triggering astrocyte-mediated neuronal degeneration. We further find that NO acts through cGMP signalling in neurons to promote cell death. Glial cells themselves also degenerate, via the DNA damage response and p53. Our findings thus define a specific mechanism for glial-induced non-cell autonomous neuronal cell death, and identify a potential therapeutic target for reducing cellular toxicity in Alexander disease, and possibly other neurodegenerative disorders with glial dysfunction. PMID:26608817

  8. [Cerebrovascular complications of immunologically mediated heparin-induced thrombocytopenia].

    PubMed

    Macha, K; Kloska, S; Dörfler, A; Raaz-Schrauder, D; Schwab, S; Köhrmann, M; Seifert, F

    2014-03-01

    Immunologically mediated heparin-induced thrombocytopenia (HIT) is a thrombotic disease caused by antibodies occurring after heparin exposure. Thrombocytopenia occurs within a few days after heparin exposure, about half of HIT-patients develop venous or arterial thrombotic complications. Neurological complications of HIT are mainly ischaemic stroke and sinus vein thrombosis. To ensure the primary clinical diagnosis functional and immunological assays for antibody detection are available. The probability for the occurrence of HIT depends on the nature of heparin employed (LMWH vs. UFH) and individual patient characteristics such as gender and primary disease (medical vs. surgical patients). In the case of suspected HIT heparin administration should be discontinued immediately and replaced by an alternative anticoagulation to prevent the expansion or development of further thrombotic complications. Herein we report a case of a patient suffering from HIT-associated embolic cerebral ischaemic stroke. PMID:24615586

  9. Peroxynitrite mediates testosterone-induced vasodilation of microvascular resistance vessels.

    PubMed

    Puttabyatappa, Yashoda; Stallone, John N; Ergul, Adviye; El-Remessy, Azza B; Kumar, Sanjiv; Black, Stephen; Johnson, Maribeth; Owen, Mary P; White, Richard E

    2013-04-01

    Our knowledge of how androgens influence the cardiovascular system is far from complete, and this lack of understanding is especially true of how androgens affect resistance vessels. Our aim was to identify the signaling mechanisms stimulated by testosterone (TES) in microvascular arteries and to understand how these mechanisms mediate TES-induced vasodilation. Mesenteric microvessels were isolated from male Sprague-Dawley rats. Tension studies demonstrated a rapid, concentration-dependent, vasodilatory response to TES that did not involve protein synthesis or aromatization to 17β-estradiol. Dichlorofluorescein fluorescence and nitrotyrosine immunoblot experiments indicated that TES stimulated peroxynitrite formation in microvessels, and functional studies demonstrated that TES-induced vasodilation was inhibited by scavenging peroxynitrite. As predicted, TES enhanced the production of both peroxynitrite precursors (i.e., superoxide and nitic oxide), and xanthine oxidase was identified as the likely source of TES-stimulated superoxide production. Functional and biochemical studies indicated that TES signaling involved activity of the phosphoinositide 3 (PI3) kinase-protein kinase B (Akt) cascade initiated by activation of the androgen receptor and culminated in enhanced production of cGMP and microvascular vasodilation. These findings, derived from a variety of analytical and functional approaches, provide evidence for a novel nongenomic signaling mechanism for androgen action in the microvasculature: TES-stimulated vasodilation mediated primarily by peroxynitrite formed from xanthine oxidase-generated superoxide and NO. This response was associated with activation of the PI3 kinase-Akt signaling cascade initiated by activation of the androgen receptor. We propose this mechanism could account for TES-stimulated cGMP production in microvessels and, ultimately, vasodilation. PMID:23318471

  10. Peroxynitrite Mediates Testosterone-Induced Vasodilation of Microvascular Resistance Vessels

    PubMed Central

    Puttabyatappa, Yashoda; Stallone, John N.; Ergul, Adviye; El-Remessy, Azza B.; Kumar, Sanjiv; Black, Stephen; Johnson, Maribeth; Owen, Mary P.

    2013-01-01

    Our knowledge of how androgens influence the cardiovascular system is far from complete, and this lack of understanding is especially true of how androgens affect resistance vessels. Our aim was to identify the signaling mechanisms stimulated by testosterone (TES) in microvascular arteries and to understand how these mechanisms mediate TES-induced vasodilation. Mesenteric microvessels were isolated from male Sprague-Dawley rats. Tension studies demonstrated a rapid, concentration-dependent, vasodilatory response to TES that did not involve protein synthesis or aromatization to 17β-estradiol. Dichlorofluorescein fluorescence and nitrotyrosine immunoblot experiments indicated that TES stimulated peroxynitrite formation in microvessels, and functional studies demonstrated that TES-induced vasodilation was inhibited by scavenging peroxynitrite. As predicted, TES enhanced the production of both peroxynitrite precursors (i.e., superoxide and nitic oxide), and xanthine oxidase was identified as the likely source of TES-stimulated superoxide production. Functional and biochemical studies indicated that TES signaling involved activity of the phosphoinositide 3 (PI3) kinase-protein kinase B (Akt) cascade initiated by activation of the androgen receptor and culminated in enhanced production of cGMP and microvascular vasodilation. These findings, derived from a variety of analytical and functional approaches, provide evidence for a novel nongenomic signaling mechanism for androgen action in the microvasculature: TES-stimulated vasodilation mediated primarily by peroxynitrite formed from xanthine oxidase-generated superoxide and NO. This response was associated with activation of the PI3 kinase-Akt signaling cascade initiated by activation of the androgen receptor. We propose this mechanism could account for TES-stimulated cGMP production in microvessels and, ultimately, vasodilation. PMID:23318471

  11. TET2-mediated 5-hydroxymethylcytosine induces genetic instability and mutagenesis.

    PubMed

    Mahfoudhi, Emna; Talhaoui, Ibtissam; Cabagnols, Xenia; Della Valle, Véronique; Secardin, Lise; Rameau, Philippe; Bernard, Olivier A; Ishchenko, Alexander A; Abbes, Salem; Vainchenker, William; Saparbaev, Murat; Plo, Isabelle

    2016-07-01

    The family of Ten-Eleven Translocation (TET) proteins is implicated in the process of active DNA demethylation and thus in epigenetic regulation. TET 1, 2 and 3 proteins are oxygenases that can hydroxylate 5-methylcytosine (5-mC) into 5-hydroxymethylcytosine (5-hmC) and further oxidize 5-hmC into 5-formylcytosine (5-fC) and 5-carboxylcytosine (5-caC). The base excision repair (BER) pathway removes the resulting 5-fC and 5-caC bases paired with a guanine and replaces them with regular cytosine. The question arises whether active modification of 5-mC residues and their subsequent elimination could affect the genomic DNA stability. Here, we generated two inducible cell lines (Ba/F3-EPOR, and UT7) overexpressing wild-type or catalytically inactive human TET2 proteins. Wild-type TET2 induction resulted in an increased level of 5-hmC and a cell cycle defect in S phase associated with higher level of phosphorylated P53, chromosomal and centrosomal abnormalities. Furthermore, in a thymine-DNA glycosylase (Tdg) deficient context, the TET2-mediated increase of 5-hmC induces mutagenesis characterized by GC>AT transitions in CpG context suggesting a mutagenic potential of 5-hmC metabolites. Altogether, these data suggest that TET2 activity and the levels of 5-hmC and its derivatives should be tightly controlled to avoid genetic and chromosomal instabilities. Moreover, TET2-mediated active demethylation might be a very dangerous process if used to entirely demethylate the genome and might rather be used only at specific loci. PMID:27289557

  12. Indirect electroanalytical detection of phenols.

    PubMed

    Kolliopoulos, Athanasios V; Kampouris, Dimitrios K; Banks, Craig E

    2015-05-01

    A novel indirect electrochemical protocol for the electroanalytical detection of phenols is presented for the first time. This methodology is demonstrated with the indirect determination of the target analytes phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol through an electrochemically adapted optical protocol. This electrochemical adaptation allows the determination of the above mentioned phenols without the use of any oxidising agents, as is the case in the optical method, where pyrazoline compounds (mediators) chemically react with the target phenols forming a quinoneimine product which is electrochemically active providing an indirect analytical signal to measure the target phenol(s). A range of commercially available pyrazoline substitution products, namely 4-dimethylaminoantipyrine, antipyrine, 3-methyl-1-(2-phenylethyl)-2-pyrazolin-5-one, 3-amino-1-(1-naphthylmethyl)-2-Pyrazolin-5-one, 4-amino-1,2-dimethyl-3-pentadecyl-3-pyrazolin-5-one hydrochloride, 3-amino-1-(2-amino-4-methylsulfonylphenyl)-2-pyrazolin-5-one hydrochloride and 4-aminoantipyrine are evaluated as mediators for the indirect detection of phenols. The indirect electrochemical detection of phenol, 2-chlorophenol, 4-chlorophenol and 2,4-dichlorophenol through the use of 4-aminoantipyrine as a mediator are successfully determined in drinking water samples at analytically useful levels. Finally, the comparison of the direct (no mediator) and the proposed indirect determination (with 4-aminoantipyrine) towards the analytical detection of the target phenols in drinking water is presented. The limitation of the proposed electroanalytical protocol is quantified for all the four target phenols. PMID:25771897

  13. Nanoparticle-Mediated Mitochondrial Damage Induces Apoptosis in Cancer.

    PubMed

    Mallick, Abhik; More, Piyush; Syed, Muhammed Muazzam Kamil; Basu, Sudipta

    2016-06-01

    Detouring of conventional DNA damaging anticancer drugs into mitochondria to damage mitochondrial DNA is evolving as a promising strategy in chemotherapy. Inhibiting single target in mitochondria would eventually lead to the emergence of drug resistance. Moreover, targeting mitochondria selectively in cancer cells, keeping them intact in healthy cells, remains a major challenge. Herein, triphenylphosphine (TPP)-coated positively charged 131.6 nm spherical nanoparticles (NPs) comprised of α-tocopheryl succinate (TOS, inhibitor of complex II in electron transport chain) and obatoclax (Obt, inhibitor of Bcl-2) were engineered. The TOS-TPP-Obt-NPs entered into acidic lysosomes via macropinocytosis, followed by lysosomal escape and finally homed into mitochondria over a period of 24 h. Subsequently, these TOS-TPP-Obt-NPs triggered mitochondrial outer membrane permeabilization (MOMP) by inhibiting antiapoptotic Bcl-2, leading to Cytochrome C release. These TOS-TPP-Obt-NPs mediated mitochondrial damage induced cellular apoptosis through caspase-9 and caspase-3 cleavage to show improved efficacy in HeLa cells. Moreover, TOS-TPP-Obt-NPs induced MOMP in drug-resistant triple negative breast cancer cells (MDA-MB-231), leading to remarkable efficacy, compared to the combination of free drugs in higher drug concentrations. Results presented here clearly stimulate the usage of multiple drugs to perturb simultaneously diverse targets, selectively in mitochondria, as next-generation cancer therapeutics. PMID:27160664

  14. LIG4 mediates Wnt signalling-induced radioresistance.

    PubMed

    Jun, Sohee; Jung, Youn-Sang; Suh, Han Na; Wang, Wenqi; Kim, Moon Jong; Oh, Young Sun; Lien, Esther M; Shen, Xi; Matsumoto, Yoshihisa; McCrea, Pierre D; Li, Lei; Chen, Junjie; Park, Jae-Il

    2016-01-01

    Despite the implication of Wnt signalling in radioresistance, the underlying mechanisms are unknown. Here we find that high Wnt signalling is associated with radioresistance in colorectal cancer (CRC) cells and intestinal stem cells (ISCs). We find that LIG4, a DNA ligase in DNA double-strand break repair, is a direct target of β-catenin. Wnt signalling enhances non-homologous end-joining repair in CRC, which is mediated by LIG4 transactivated by β-catenin. During radiation-induced intestinal regeneration, LIG4 mainly expressed in the crypts is conditionally upregulated in ISCs, accompanied by Wnt/β-catenin signalling activation. Importantly, among the DNA repair genes, LIG4 is highly upregulated in human CRC cells, in correlation with β-catenin hyperactivation. Furthermore, blocking LIG4 sensitizes CRC cells to radiation. Our results reveal the molecular mechanism of Wnt signalling-induced radioresistance in CRC and ISCs, and further unveils the unexpected convergence between Wnt signalling and DNA repair pathways in tumorigenesis and tissue regeneration. PMID:27009971

  15. Signals mediating Klotho-induced neuroprotection in hippocampal neuronal cells.

    PubMed

    Cheng, Meng-Fu; Chen, Li-Jen; Niu, Ho-Shan; Yang, Ting-Ting; Lin, Kao-Chang; Cheng, Juei-Tang

    2015-01-01

    The erythropoietin (Epo) receptor (EpoR) is expressed in the brain and was shown to have neuroprotective effects against brain damage in animal models. A recent study indicated that EpoR and its activity are the downstream effectors of Klotho for cytoprotection in the kidney. Thus, we propose that Klotho can stimulate the expression of EpoR in neuronal cells to enhance Epo-mediated protection. H19-7 hippocampal neuronal cells were treated with recombinant Klotho. In H19-7 cells, Klotho increased the expression of both the EpoR protein and mRNA. Klotho also enhanced the transcription activity of the EpoR promoter in H19-7 cells. Moreover, Klotho augmented the Epo-triggered phosphorylation of Jak2 and Stat5 and protected H19-7 cells from hydrogen peroxide cytotoxicity. The silencing of EpoR abolished the protective effect of Klotho against peroxide-induced cytotoxicity. Finally, the silencing of GATA1 diminished the Klotho-induced increase in EpoR protein and mRNA expression as well as its promoter activity. In conclusion, Klotho increased EpoR expression in neuronal cells through GATA1, thereby enabling EpoR to function as a cytoprotective protein against oxidative injury. PMID:25856523

  16. LIG4 mediates Wnt signalling-induced radioresistance

    PubMed Central

    Jun, Sohee; Jung, Youn-Sang; Suh, Han Na; Wang, Wenqi; Kim, Moon Jong; Oh, Young Sun; Lien, Esther M.; Shen, Xi; Matsumoto, Yoshihisa; McCrea, Pierre D.; Li, Lei; Chen, Junjie; Park, Jae-Il

    2016-01-01

    Despite the implication of Wnt signalling in radioresistance, the underlying mechanisms are unknown. Here we find that high Wnt signalling is associated with radioresistance in colorectal cancer (CRC) cells and intestinal stem cells (ISCs). We find that LIG4, a DNA ligase in DNA double-strand break repair, is a direct target of β-catenin. Wnt signalling enhances non-homologous end-joining repair in CRC, which is mediated by LIG4 transactivated by β-catenin. During radiation-induced intestinal regeneration, LIG4 mainly expressed in the crypts is conditionally upregulated in ISCs, accompanied by Wnt/β-catenin signalling activation. Importantly, among the DNA repair genes, LIG4 is highly upregulated in human CRC cells, in correlation with β-catenin hyperactivation. Furthermore, blocking LIG4 sensitizes CRC cells to radiation. Our results reveal the molecular mechanism of Wnt signalling-induced radioresistance in CRC and ISCs, and further unveils the unexpected convergence between Wnt signalling and DNA repair pathways in tumorigenesis and tissue regeneration. PMID:27009971

  17. Oxytocin mediates copulation-induced hypoalgesia of male rats.

    PubMed

    Futagami, Hiroko; Sakuma, Yasuo; Kondo, Yasuhiko

    2016-04-01

    Copulatory behavior has been reported to raise the pain threshold in male rats. In this study, we examined the effect of copulatory behavior with or without ejaculation on pain threshold measured by electrical shock via an electrode attached to the tail. It was demonstrated that ejaculation is not necessary to raise the pain threshold in male rats. In addition, we examined whether oxytocin, a hypothalamic neuropeptide, was involved in copulation-induced hypoalgesia. Sexually experienced males were subjected to stereotaxic implantation of a guide cannula targeting the lateral ventricle. After the recovery period, half of the males were intracerebroventricularly treated with an oxytocin antagonist (OTA, 100ng d(CH2)51,Tyr(Me)2,Thr4, Orn8,Tyr-NH29]-vasotocin/1μL saline) and the remaining half were administered saline without anesthesia. Fifteen minutes later, half of each group were given sexual behavior with receptive females. We found no effect of OTA on sexual activity. Immediately after ejaculation, pain threshold was measured. While raised pain threshold was observed after sexual behavior in saline-treated males, no change in pain threshold was found in OTA-treated males even after copulation. The results suggest that central oxytocin mediates copulation-induced hypoalgesia in male rats. PMID:26960009

  18. Phytochemicals Mediated Remediation of Neurotoxicity Induced by Heavy Metals

    PubMed Central

    Gupta, Vivek Kumar; Singh, Shweta; Agrawal, Anju; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavy metals continuously released from various sources. Different heavy metals have been reported to generate adverse effects in many ways. Heavy metals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavy metals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavy metals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity. PMID:26618004

  19. Phytochemicals Mediated Remediation of Neurotoxicity Induced by Heavy Metals.

    PubMed

    Gupta, Vivek Kumar; Singh, Shweta; Agrawal, Anju; Siddiqi, Nikhat Jamal; Sharma, Bechan

    2015-01-01

    Almost all the environmental components including both the abiotic and biotic factors have been consistently threatened by excessive contamination of heavy metals continuously released from various sources. Different heavy metals have been reported to generate adverse effects in many ways. Heavy metals induced neurotoxicity and impairment in signalling cascade leading to cell death (apoptosis) has been indicated by several workers. On one hand, these metals are required by the cellular systems to regulate various biological functions of normal cells, while on the other their biomagnification in the cellular systems produces adverse effects. The mechanism by which the heavy metals induce neurotoxicity follows free radicals production pathway(s) specially the generation of reactive oxygen species and reactive nitrogen species. These free radicals produced in excess have been shown to create an imbalance between the oxidative and antioxidative systems leading to emergence of oxidative stress, which may cause necrosis, DNA damage, and many neurodegenerative disorders. This mini review summarizes the current knowledge available on the protective role of varied natural products isolated from different herbs/plants in imparting protection against heavy metals (cadmium, lead, arsenic, and mercury) mediated neurotoxicity. PMID:26618004

  20. TRPA1 receptors mediate environmental irritant-induced meningeal vasodilatation

    PubMed Central

    Kunkler, Phillip Edward; Ballard, Carrie Jo; Oxford, Gerry Stephen; Hurley, Joyce Harts

    2010-01-01

    The TRPA1 receptor is a member of the transient receptor potential (TRP) family of ion channels expressed in nociceptive neurons. TRPA1 receptors are targeted by pungent compounds from mustard and garlic and environmental irritants such as formaldehyde and acrolein. Ingestion or inhalation of these chemical agents causes irritation and burning in the nasal and oral mucosa and respiratory lining. Headaches have been widely reported to be induced by inhalation of environmental irritants, but it is unclear how these agents produce headache. Stimulation of trigeminal neurons releases CGRP and substance P and induces neurogenic inflammation associated with the pain of migraine. Here we test the hypothesis that activation of TRPA1 receptors are the mechanistic link between environmental irritants and peptide mediated neurogenic inflammation. Known TRPA1 agonists and environmental irritants stimulate CGRP release from dissociated rat trigeminal ganglia neurons and this release is blocked by a selective TRPA1 antagonist, HC-030031. Further, TRPA1 agonists and environmental irritants increase meningeal blood flow following intranasal administration. Prior dural application of the CGRP antagonist, CGRP8–37, or intranasal or dural administration of HC-030031, blocks the increases in blood flow elicited by environmental irritants. Together these results demonstrate that TRPA1 receptor activation by environmental irritants stimulates CGRP release and increases cerebral blood flow. We suggest that these events contribute to headache associated with environmental irritants. PMID:21075522

  1. Indirect detection of superoxide in RAW 264.7 macrophage cells using microchip electrophoresis coupled to laser-induced fluorescence.

    PubMed

    de Campos, Richard P S; Siegel, Joseph M; Fresta, Claudia G; Caruso, Giuseppe; da Silva, José A F; Lunte, Susan M

    2015-09-01

    Superoxide, a naturally produced reactive oxygen species (ROS) in the human body, is involved in many pathological and physiological signaling processes. However, if superoxide formation is left unregulated, overproduction can lead to oxidative damage to important biomolecules, such as DNA, lipids, and proteins. Superoxide can also lead to the formation of peroxynitrite, an extremely hazardous substance, through its reaction with endogenously produced nitric oxide. Despite its importance, quantitative information regarding superoxide production is difficult to obtain due to its high reactivity and low concentrations in vivo. MitoHE, a fluorescent probe that specifically reacts with superoxide, was used in conjunction with microchip electrophoresis (ME) and laser-induced fluorescence (LIF) detection to investigate changes in superoxide production by RAW 264.7 macrophage cells following stimulation with phorbol 12-myristate 13-acetate (PMA). Stimulation was performed in the presence and absence of the superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC) and 2-metoxyestradiol (2-ME). The addition of these inhibitors resulted in an increase in the amount of superoxide specific product (2-OH-MitoE(+)) from 0.08 ± 0.01 fmol (0.17 ± 0.03 mM) in native cells to 1.26 ± 0.06 fmol (2.5 ± 0.1 mM) after PMA treatment. This corresponds to an approximately 15-fold increase in intracellular concentration per cell. Furthermore, the addition of 3-morpholino-sydnonimine (SIN-1) to the cells during incubation resulted in the production of 0.061 ± 0.006 fmol (0.12 ± 0.01 mM) of 2-OH-MitoE(+) per cell on average. These results demonstrate that indirect superoxide detection coupled with the use of SOD inhibitors and a separation method is a viable method to discriminate the 2-OH-MitoE(+) signal from possible interferences. PMID:26159570

  2. Research resource: estrogen-driven prolactin-mediated gene-expression networks in hormone-induced prostatic intraepithelial neoplasia.

    PubMed

    Tam, Neville N C; Szeto, Carol Y Y; Freudenberg, Johannes M; Fullenkamp, Amy N; Medvedovic, Mario; Ho, Shuk-Mei

    2010-11-01

    Cotreatment with testosterone (T) and 17β-estradiol (E2) is an established regimen for inducing of prostatic intraepithelial neoplasia (PIN) and prostate cancer in rodent models. We previously used the pure antiestrogen ICI 182,780 (ICI) and bromocriptine, a dopamine receptor agonist, to inhibit PIN induction and systemic hyperprolactinemia in Noble rats and found that the carcinogenic action of T+E2 is mediated directly by the effects of E2 on the prostate and/or indirectly via E2-induced hyperprolactinemia. In this study, we delineate the specific action(s) of E2 and prolactin (PRL) in early prostate carcinogenesis by an integrated approach combining global transcription profiling, gene ontology, and gene-network mapping. We identified 2504 differentially expressed genes in the T+E2-treated lateral prostate. The changes in expression of a subset of 1990 genes (∼80%) were blocked upon cotreatment with ICI and bromocriptine, respectively, whereas those of 262 genes (∼10%) were blocked only by treatment with ICI, suggesting that E2-induced pituitary PRL is the primary mediator of the prostatic transcriptional response to the altered hormone milieu. Bioinformatics analyses identified hormone-responsive gene networks involved in immune responses, stromal tissue remodeling, and the ERK pathway. In particular, our data suggest that IL-1β may mediate, at least in part, hormone-induced changes in gene expression during PIN formation. Together, these data highlight the importance of pituitary PRL in estrogen-induced prostate tumorigenesis. The identification of both E2- and pituitary PRL-responsive genes provides a comprehensive resource for future investigations of the complex mechanisms by which changes in the endocrine milieu contribute to prostate carcinogenesis in vivo. PMID:20861223

  3. Vigabatrin-induced retinal toxicity is partially mediated by signaling in rod and cone photoreceptors.

    PubMed

    Yang, Jin; Naumann, Matthew C; Tsai, Yi-Ting; Tosi, Joaquin; Erol, Deniz; Lin, Chyuan-Sheng; Davis, Richard J; Tsang, Stephen H

    2012-01-01

    Vigabatrin (VGB) is a commonly prescribed antiepileptic drug designed to inhibit GABA-transaminase, effectively halting seizures. Unfortunately, VGB treatment is also associated with the highest frequencies of peripheral visual field constriction of any of the antiepileptic drugs and the mechanisms that lead to these visual field defects are uncertain. Recent studies have demonstrated light exposure exacerbates vigabatrin-induced retinal toxicity. We further assessed this relationship by examining the effects of vigabatrin treatment on the retinal structures of mice with genetically altered photoreception. In keeping with previous studies, we detected increased toxicity in mice exposed to continuous light. To study whether cone or rod photoreceptor function was involved in the pathway to toxicity, we tested mice with mutations in the cone-specific Gnat2 or rod-specific Pde6g genes, and found the mutations significantly reduced VGB toxicity. Our results confirm light is a significant enhancer of vigabatrin toxicity and that a portion of this is mediated, directly or indirectly, by phototransduction signaling in rod and cone photoreceptors. PMID:22970106

  4. TRPM2 channels mediate acetaminophen-induced liver damage.

    PubMed

    Kheradpezhouh, Ehsan; Ma, Linlin; Morphett, Arthur; Barritt, Greg J; Rychkov, Grigori Y

    2014-02-25

    Acetaminophen (paracetamol) is the most frequently used analgesic and antipyretic drug available over the counter. At the same time, acetaminophen overdose is the most common cause of acute liver failure and the leading cause of chronic liver damage requiring liver transplantation in developed countries. Acetaminophen overdose causes a multitude of interrelated biochemical reactions in hepatocytes including the formation of reactive oxygen species, deregulation of Ca(2+) homeostasis, covalent modification and oxidation of proteins, lipid peroxidation, and DNA fragmentation. Although an increase in intracellular Ca(2+) concentration in hepatocytes is a known consequence of acetaminophen overdose, its importance in acetaminophen-induced liver toxicity is not well understood, primarily due to lack of knowledge about the source of the Ca(2+) rise. Here we report that the channel responsible for Ca(2+) entry in hepatocytes in acetaminophen overdose is the Transient Receptor Potential Melanostatine 2 (TRPM2) cation channel. We show by whole-cell patch clamping that treatment of hepatocytes with acetaminophen results in activation of a cation current similar to that activated by H2O2 or the intracellular application of ADP ribose. siRNA-mediated knockdown of TRPM2 in hepatocytes inhibits activation of the current by either acetaminophen or H2O2. In TRPM2 knockout mice, acetaminophen-induced liver damage, assessed by the blood concentration of liver enzymes and liver histology, is significantly diminished compared with wild-type mice. The presented data strongly suggest that TRPM2 channels are essential in the mechanism of acetaminophen-induced hepatocellular death. PMID:24569808

  5. Hyperglycemia-induced diaphragm weakness is mediated by oxidative stress

    PubMed Central

    2014-01-01

    Introduction A major consequence of ICU-acquired weakness (ICUAW) is diaphragm weakness, which prolongs the duration of mechanical ventilation. Hyperglycemia (HG) is a risk factor for ICUAW. However, the mechanisms underlying HG-induced respiratory muscle weakness are not known. Excessive reactive oxygen species (ROS) injure multiple tissues during HG, but only one study suggests that excessive ROS generation may be linked to HG-induced diaphragm weakness. We hypothesized that HG-induced diaphragm dysfunction is mediated by excessive superoxide generation and that administration of a specific superoxide scavenger, polyethylene glycol superoxide dismutase (PEG-SOD), would ameliorate these effects. Methods HG was induced in rats using streptozotocin (60 mg/kg intravenously) and the following groups assessed at two weeks: controls, HG, HG + PEG-SOD (2,000U/kg/d intraperitoneally for seven days), and HG + denatured (dn)PEG-SOD (2000U/kg/d intraperitoneally for seven days). PEG-SOD and dnPEG-SOD were administered on day 8, we measured diaphragm specific force generation in muscle strips, force-pCa relationships in single permeabilized fibers, contractile protein content and indices of oxidative stress. Results HG reduced diaphragm specific force generation, altered single fiber force-pCa relationships, depleted troponin T, and increased oxidative stress. PEG-SOD prevented HG-induced reductions in diaphragm specific force generation (for example 80 Hz force was 26.4 ± 0.9, 15.4 ± 0.9, 24.0 ± 1.5 and 14.9 ± 0.9 N/cm2 for control, HG, HG + PEG-SOD, and HG + dnPEG-SOD groups, respectively, P <0.001). PEG-SOD also restored HG-induced reductions in diaphragm single fiber force generation (for example, Fmax was 182.9 ± 1.8, 85.7 ± 2.0, 148.6 ± 2.4 and 90.9 ± 1.5 kPa in control, HG, HG + PEG-SOD, and HG + dnPEG-SOD groups, respectively, P <0.001). HG-induced troponin T depletion, protein nitrotyrosine formation

  6. IL-17-induced Act1-mediated signaling is critical for cuprizone-induced demyelination

    PubMed Central

    Kang, Zizhen; Liu, Liping; Spangler, Roo; Spear, Charles; Wang, Chenhui; Gulen, Muhammet Fatih; Veenstra, Mike; Ouyang, Wenjun; Ransohoff, Richard M.; Li, Xiaoxia

    2012-01-01

    Cuprizone inhibits mitochondrial function and induces demyelination in the corpus callosum which resembles pattern III lesions in multiple sclerosis (MS) patients. However, the molecular and cellular mechanism by which cuprizone induces demyelination remains unclear. Interleukin-17 (IL-17) secreted by T helper 17 (Th17) cells and γδT cells are essential in the development of experimental autoimmune encephalomyelitis (EAE). In this study, we examined the importance of IL-17 signaling in cuprizone-induced demyelination. We found that mice deficient in IL-17A, IL-17RC and adaptor protein Act1 (of IL-17R) all had reduced demyelination accompanied by lessened microglial and polydendrocyte cellular reactivity compared to that in wild-type mice in response to cuprizone feeding, demonstrating the essential role of IL-17-induced Act1-mediated signaling in cuprizone-induced demyelination. Importantly, specific deletion of Act1 in astrocytes reduced the severity of tissue injury in this model, indicating the critical role of CNS resident cells in the pathogenesis of cuprizone-induced demyelination. In cuprizone-fed mice IL-17 was produced by CNS CD3+ T cells suggesting a source of IL-17 in CNS upon cuprizone treatment. PMID:22699909

  7. IL-17-induced Act1-mediated signaling is critical for cuprizone-induced demyelination.

    PubMed

    Kang, Zizhen; Liu, Liping; Spangler, Roo; Spear, Charles; Wang, Chenhui; Gulen, Muhammet Fatih; Veenstra, Mike; Ouyang, Wenjun; Ransohoff, Richard M; Li, Xiaoxia

    2012-06-13

    Cuprizone inhibits mitochondrial function and induces demyelination in the corpus callosum, which resembles pattern III lesions in multiple sclerosis patients. However, the molecular and cellular mechanism by which cuprizone induces demyelination remains unclear. Interleukin-17 (IL-17) secreted by T helper 17 cells and γδT cells are essential in the development of experimental autoimmune encephalomyelitis. In this study, we examined the importance of IL-17 signaling in cuprizone-induced demyelination. We found that mice deficient in IL-17A, IL-17 receptor C (IL-17RC), and adaptor protein Act1 (of IL-17R) all had reduced demyelination accompanied by lessened microglial and polydendrocyte cellular reactivity compared with that in wild-type mice in response to cuprizone feeding, demonstrating the essential role of IL-17-induced Act1-mediated signaling in cuprizone-induced demyelination. Importantly, specific deletion of Act1 in astrocytes reduced the severity of tissue injury in this model, indicating the critical role of CNS resident cells in the pathogenesis of cuprizone-induced demyelination. In cuprizone-fed mice, IL-17 was produced by CNS CD3(+) T cells, suggesting a source of IL-17 in CNS upon cuprizone treatment. PMID:22699909

  8. High quality reduced graphene oxide flakes by fast kinetically controlled and clean indirect UV-induced radical reduction

    NASA Astrophysics Data System (ADS)

    Flyunt, Roman; Knolle, Wolfgang; Kahnt, Axel; Halbig, Christian E.; Lotnyk, Andriy; Häupl, Tilmann; Prager, Andrea; Eigler, Siegfried; Abel, Bernd

    2016-03-01

    This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the GO is not excited directly. While the direct photoexcitation of aqueous GO (when GO is the only light-absorbing component) takes several hours of reaction time at ambient temperature (4 h) leading only to a partial GO reduction, the addition of small amounts of isopropanol and acetone (2% and 1%) leads to a dramatically shortened reaction time by more than two orders of magnitude (2 min) and a very efficient and soft reduction of graphene oxide. This method avoids the formation of non-volatile species and in turn contamination of the produced rGO and it is based on the highly efficient generation of reducing carbon centered isopropanol radicals via the reaction of triplet acetone with isopropanol. While the direct photolysis of GO dispersions easily leads to degradation of the carbon lattice of GO and thus to a relatively low electric conductivity of the films of flakes, our indirect photoreduction of GO instead largely avoids the formation of defects, keeping the carbon lattice intact. Mechanisms of the direct and indirect photoreduction of GO have been elucidated and compared. Raman spectroscopy, XPS and conductivity measurements prove the efficiency of the indirect photoreduction in comparison with the state-of-the-art reduction method for GO (hydriodic acid/trifluoroacetic acid). The rapid reduction times and water solvent containing only small amounts of isopropanol and acetone may allow easy process up-scaling for technical applications and low-energy consumption.This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the

  9. High quality reduced graphene oxide flakes by fast kinetically controlled and clean indirect UV-induced radical reduction.

    PubMed

    Flyunt, Roman; Knolle, Wolfgang; Kahnt, Axel; Halbig, Christian E; Lotnyk, Andriy; Häupl, Tilmann; Prager, Andrea; Eigler, Siegfried; Abel, Bernd

    2016-04-14

    This work highlights a surprisingly simple and kinetically controlled highly efficient indirect method for the production of high quality reduced graphene oxide (rGO) flakes via UV irradiation of aqueous dispersions of graphene oxide (GO), in which the GO is not excited directly. While the direct photoexcitation of aqueous GO (when GO is the only light-absorbing component) takes several hours of reaction time at ambient temperature (4 h) leading only to a partial GO reduction, the addition of small amounts of isopropanol and acetone (2% and 1%) leads to a dramatically shortened reaction time by more than two orders of magnitude (2 min) and a very efficient and soft reduction of graphene oxide. This method avoids the formation of non-volatile species and in turn contamination of the produced rGO and it is based on the highly efficient generation of reducing carbon centered isopropanol radicals via the reaction of triplet acetone with isopropanol. While the direct photolysis of GO dispersions easily leads to degradation of the carbon lattice of GO and thus to a relatively low electric conductivity of the films of flakes, our indirect photoreduction of GO instead largely avoids the formation of defects, keeping the carbon lattice intact. Mechanisms of the direct and indirect photoreduction of GO have been elucidated and compared. Raman spectroscopy, XPS and conductivity measurements prove the efficiency of the indirect photoreduction in comparison with the state-of-the-art reduction method for GO (hydriodic acid/trifluoroacetic acid). The rapid reduction times and water solvent containing only small amounts of isopropanol and acetone may allow easy process up-scaling for technical applications and low-energy consumption. PMID:26984451

  10. Reduced platelet-mediated and enhanced leukocyte-mediated fibrinolysis in experimentally induced diabetes in rats

    SciTech Connect

    Winocour, P.D.; Colwell, J.A.

    1985-05-01

    Studies of fibrinolytic activity in diabetes mellitus have produced conflicting results. This may be a result of methodologic insensitivity or of variable contributions of the different blood components to whole blood fibrinolysis. To explore these two possibilities, the authors used a sensitive solid-phase radiometric assay to examine the fibrinolytic activity of whole blood, platelet-rich plasma, leukocytes, and platelet- and leukocyte-poor plasma prepared from control rats and rats with streptozocin-induced diabetes at various times after induction of diabetes. Fibrinolytic activity of whole blood from diabetic rats after 7 days was significantly reduced, and remained reduced after longer durations of diabetes up to 28 days. Platelet-rich plasma from diabetic rats had decreased fibrinolytic activity, which followed the same time course of changes as in whole blood. The platelet contribution to whole blood fibrinolysis was further reduced in vivo after 14 days of diabetes by a reduced whole blood platelet count. In contrast, fibrinolytic activity of leukocytes from diabetic rats became enhanced after 7 days of diabetes. After 49 days of diabetes, the whole blood leukocyte count was reduced, and in vivo would offset the enhanced activity. Plasma fibrinolytic activity was small compared with that of whole blood and was unaltered in diabetic rats. The authors conclude that altered platelet function contributes to decreased fibrinolytic activity of whole blood in diabetic rats, and that this may be partially offset by enhanced leukocyte-mediated fibrinolysis.

  11. Indirect inversions

    NASA Astrophysics Data System (ADS)

    Sergienko, Olga

    2013-04-01

    Since Doug MacAyeal's pioneering studies of the ice-stream basal traction optimizations by control methods, inversions for unknown parameters (e.g., basal traction, accumulation patterns, etc) have become a hallmark of the present-day ice-sheet modeling. The common feature of such inversion exercises is a direct relationship between optimized parameters and observations used in the optimization procedure. For instance, in the standard optimization for basal traction by the control method, ice-stream surface velocities constitute the control data. The optimized basal traction parameters explicitly appear in the momentum equations for the ice-stream velocities (compared to the control data). The inversion for basal traction is carried out by minimization of the cost (or objective, misfit) function that includes the momentum equations facilitated by the Lagrange multipliers. Here, we build upon this idea, and demonstrate how to optimize for parameters indirectly related to observed data using a suite of nested constraints (like Russian dolls) with additional sets of Lagrange multipliers in the cost function. This method opens the opportunity to use data from a variety of sources and types (e.g., velocities, radar layers, surface elevation changes, etc.) in the same optimization process.

  12. Lactobacillus rhamnosus GG and Streptococcus thermophilus induce suppressor of cytokine signalling 3 (SOCS3) gene expression directly and indirectly via interleukin-10 in human primary macrophages

    PubMed Central

    Latvala, S; Miettinen, M; Kekkonen, R A; Korpela, R; Julkunen, I

    2011-01-01

    In the present study we have characterized T helper type 2 (Th2) [interleukin (IL)-10]/Th1 (IL-12) cytokine expression balance in human primary macrophages stimulated with multiple non-pathogenic Gram-positive bacteria used in the food industry and as probiotic substances. Bacteria representing Lactobacillus, Bifidobacterium, Lactococcus, Leuconostoc, Propionibacterium and Streptococcus species induced anti-inflammatory IL-10 production, although quantitative differences between the bacteria were observed. S. thermophilus was able to induce IL-12 production, while the production of IL-12 induced by other bacteria remained at a low level. The highest anti-inflammatory potential was seen with bifidobacteria, as evidenced by high IL-10/IL-12 induction ratios. All studied non-pathogenic bacteria were able to stimulate the expression of suppressor of cytokine signalling (SOCS) 3 that controls the expression of proinflammatory cytokine genes. Lactobacillus and Streptococcus species induced SOCS3 mRNA expression directly in the absence of protein synthesis and indirectly via bacteria-induced IL-10 production, as demonstrated by experiments with cycloheximide (CHX) and anti-IL-10 antibodies, respectively. The mitogen-activated protein kinase (MAPK) p38 signalling pathway played a key role in bacteria-induced SOCS3 gene expression. Enhanced IL-10 production and SOCS3 gene expression induced by live non-pathogenic Lactobacillus and Streptococcus is also likely to contribute to their immunoregulatory effects in vivo. PMID:21545585

  13. Adenovirus-mediated siRNA targeting CXCR2 attenuates titanium particle-induced osteolysis by suppressing osteoclast formation.

    PubMed

    Wang, Chen; Liu, Yang; Wang, Yang; Li, Hao; Zhang, Ran-Xi; He, Mi-Si; Chen, Liang; Wu, Ning-Ning; Liao, Yong; Deng, Zhong-Liang

    2016-01-01

    BACKGROUND Wear particle-induced peri-implant loosening is the most common complication affecting long-term outcomes in patients who undergo total joint arthroplasty. Wear particles and by-products from joint replacements may cause chronic local inflammation and foreign body reactions, which can in turn lead to osteolysis. Thus, inhibiting the formation and activity of osteoclasts may improve the functionality and long-term success of total joint arthroplasty. The aim of this study was to interfere with CXC chemokine receptor type 2 (CXCR2) to explore its role in wear particle-induced osteolysis. MATERIAL AND METHODS Morphological and biochemical assays were used to assess osteoclastogenesis in vivo and in vitro. CXCR2 was upregulated in osteoclast formation. RESULTS Local injection with adenovirus-mediated siRNA targeting CXCR2 inhibited titanium-induced osteolysis in a mouse calvarial model in vivo. Furthermore, siCXCR2 suppressed osteoclast formation both directly by acting on osteoclasts themselves and indirectly by altering RANKL and OPG expression in osteoblasts in vitro. CONCLUSIONS CXCR2 plays a critical role in particle-induced osteolysis, and siCXCR2 may be a novel treatment for aseptic loosening. PMID:26939934

  14. Adenovirus-Mediated siRNA Targeting CXCR2 Attenuates Titanium Particle-Induced Osteolysis by Suppressing Osteoclast Formation

    PubMed Central

    Wang, Chen; Liu, Yang; Wang, Yang; Li, Hao; Zhang, Ran-Xi; He, Mi-Si; Chen, Liang; Wu, Ning-Ning; Liao, Yong; Deng, Zhong-Liang

    2016-01-01

    Background Wear particle-induced peri-implant loosening is the most common complication affecting long-term outcomes in patients who undergo total joint arthroplasty. Wear particles and by-products from joint replacements may cause chronic local inflammation and foreign body reactions, which can in turn lead to osteolysis. Thus, inhibiting the formation and activity of osteoclasts may improve the functionality and long-term success of total joint arthroplasty. The aim of this study was to interfere with CXC chemokine receptor type 2 (CXCR2) to explore its role in wear particle-induced osteolysis. Material/Methods Morphological and biochemical assays were used to assess osteoclastogenesis in vivo and in vitro. CXCR2 was upregulated in osteoclast formation. Results Local injection with adenovirus-mediated siRNA targeting CXCR2 inhibited titanium-induced osteolysis in a mouse calvarial model in vivo. Furthermore, siCXCR2 suppressed osteoclast formation both directly by acting on osteoclasts themselves and indirectly by altering RANKL and OPG expression in osteoblasts in vitro. Conclusions CXCR2 plays a critical role in particle-induced osteolysis, and siCXCR2 may be a novel treatment for aseptic loosening. PMID:26939934

  15. HDAC3 mediates smoking-induced pancreatic cancer

    PubMed Central

    Edderkaoui, Mouad; Xu, Shiping; Chheda, Chintan; Morvaridi, Susan; Hu, Robert W.; Grippo, Paul J.; Mascariñas, Emman; Principe, Daniel R.; Knudsen, Beatrice; Xue, Jing; Habtezion, Aida; Uyeminami, Dale; Pinkerton, Kent E.; Pandol, Stephen J.

    2016-01-01

    Smoking is a major risk factor for developing pancreatic adenocarcinoma (PDAC); however, little is known about the mechanisms involved. Here we employed a genetic animal model of early stages of PDAC that overexpresses oncogenic Kras in the pancreas to investigate the mechanisms of smoking-induced promotion of the disease in vivo. We confirmed the regulation of the interactions between the tumor microenvironment cells using in vitro cellular systems. Aerial exposure to cigarette smoke stimulated development of pancreatic intraepithelial neaoplasia (PanIN) lesions associated with a tumor microenvironment-containing features of human PDAC including fibrosis, activated stellate cells, M2-macrophages and markers of epithelial-mesenchymal transition (EMT). The pro-cancer effects of smoking were prevented by Histone Deacetylase HDAC I/II inhibitor Saha. Smoking decreased histone acetylation associated with recruitment of and phenotypic changes in macrophages; which in turn, stimulated survival and induction of EMT of the pre-cancer and cancer cells. The interaction between the cancer cells and macrophages is mediated by IL-6 produced under the regulation of HDAC3 translocation to the nucleus in the cancer cells. Pharmacological and molecular inhibitions of HDAC3 decreased IL-6 levels in cancer cells. IL-6 stimulated the macrophage phenotype change through regulation of the IL-4 receptor level of the macrophage. This study demonstrates a novel pathway of interaction between cancer cells and tumor promoting macrophages involving HDAC3 and IL-6. It further demonstrates that targeting HDAC3 prevents progression of the disease and could provide a strategy for treating the disease considering that the HDAC inhibitor we used is FDA approved for a different disease. PMID:26745602

  16. A serum component mediates food restriction-induced growth attenuation.

    PubMed

    Pando, Rakefet; Shtaif, Biana; Phillip, Moshe; Gat-Yablonski, Galia

    2014-03-01

    Proper nutrition in terms of calories and essential food components is required to maximize longitudinal growth in children. Our previous study showed that prepubertal male rats subjected to 10 days of 40% food restriction (RES) exhibited a dramatic reduction in weight and epiphyseal growth plate height, as well as changes in gene expression and microRNAs (miRNAs) in the epiphyseal growth plate. These findings reversed rapidly after renewal of the regular food supply (catch-up [CU]). To further elucidate the mechanisms underlying the nutrition-growth association, serum collected from the RES and CU rats and control rats fed ad libitum (AL) was added to the culture medium of the chondrocyte cell line ATDC5 (instead of fetal calf serum). Serum from the RES group induced a reduction in cell viability (25%, P < .05) concomitant with an increase in cell differentiation compared with that for the AL group serum. The most interesting observation, in our opinion, was the significant reduction in the expression of specific miRNAs, including the chondro-specific miR-140. These effects were not observed for serum from refed (CU) rats. Serum levels of IGF-I, leptin, and fibroblast growth factor 21 were reduced by food restriction. The addition of IGF-I and leptin to the culture increased cell viability, whereas fibroblast growth factor 21 reduced it, suggesting the involvement of IGF-I, leptin, and possibly other still unidentified serum factors in chondrocyte cell growth. In conclusion, specific miRNAs respond to nutritional cues, and these effects are mediated by serum-borne factors. These results may promote the development of superior interventions for children with malnutrition and growth abnormalities. PMID:24456162

  17. Unusual shift from IgE-mediated milk allergy to food protein-induced enterocolitis syndrome.

    PubMed

    Banzato, C; Piacentini, G L; Comberiati, P; Mazzei, F; Boner, A L; Peroni, D G

    2013-12-01

    Food protein-induced enterocolitis syndrome (FPIES) is a potentially severe non-IgE-mediated food allergy usually caused by cow's milk or soy, and more rarely by solid foods such as rice, oats, barley, chicken, turkey, egg white, green peas and peanuts. In children with FPIES, the presence of specific IgE antibodies to the causative food, either at presentation or during follow-up, defines an "atypical form" of FPIES characterized by a lesser probability of developing tolerance and a potential progression to typical IgE-mediated hypersensitivity. Although it is uncommon, the shift from non-IgE-mediated milk-protein induced enterocolitis syndrome to IgE-mediated milk allergy has recently been described. We report the first case, to our knowledge, of a shift from IgE-mediated cow's milk allergy to pure non-IgE-mediated FPIES, in a 4-month-old male infant. PMID:24619083

  18. GR SUMOylation and formation of an SUMO-SMRT/NCoR1-HDAC3 repressing complex is mandatory for GC-induced IR nGRE-mediated transrepression.

    PubMed

    Hua, Guoqiang; Paulen, Laetitia; Chambon, Pierre

    2016-02-01

    Unique among the nuclear receptor superfamily, the glucocorticoid (GC) receptor (GR) can exert three distinct transcriptional regulatory functions on binding of a single natural (cortisol in human and corticosterone in mice) and synthetic [e.g., dexamethasone (Dex)] hormone. The molecular mechanisms underlying GC-induced positive GC response element [(+)GRE]-mediated activation of transcription are partially understood. In contrast, these mechanisms remain elusive for GC-induced evolutionary conserved inverted repeated negative GC response element (IR nGRE)-mediated direct transrepression and for tethered indirect transrepression that is mediated by DNA-bound NF-κB/activator protein 1 (AP1)/STAT3 activators and instrumental in GC-induced anti-inflammatory activity. We demonstrate here that SUMOylation of lysine K293 (mouse K310) located within an evolutionary conserved sequence in the human GR N-terminal domain allows the formation of a GR-small ubiquitin-related modifiers (SUMOs)-NCoR1/SMRT-HDAC3 repressing complex mandatory for GC-induced IR nGRE-mediated direct repression in vitro, but does not affect transactivation. Importantly, these results were validated in vivo: in K310R mutant mice and in mice ablated selectively for nuclear receptor corepressor 1 (NCoR1)/silencing mediator for retinoid or thyroid-hormone receptors (SMRT) corepressors in skin keratinocytes, Dex-induced direct repression and the formation of repressing complexes on IR nGREs were impaired, whereas transactivation was unaffected. In mice selectively ablated for histone deacetylase 3 (HDAC3) in skin keratinocytes, GC-induced direct repression, but not bindings of GR and of corepressors NCoR1/SMRT, was abolished, indicating that HDAC3 is instrumental in IR nGRE-mediated repression. Moreover, we demonstrate that the binding of HDAC3 to IR nGREs in vivo is mediated through interaction with SMRT/NCoR1. We also show that the GR ligand binding domain (LBD) is not required for SMRT-mediated

  19. Separation and detection of VX and its methylphosphonic acid degradation products on a microchip using indirect laser-induced fluorescence.

    PubMed

    Heleg-Shabtai, Vered; Gratziany, Natzach; Liron, Zvi

    2006-05-01

    The application of indirect LIF (IDLIF) technique for on-chip electrophoretic separation and detection of the nerve agent O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothiolate (VX) and its major phosphonic degradation products, ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA) was demonstrated. Separation and detection of MPA degradation products of VX and the nerve agent isopropyl methylphosphonofluoridate (GB) are presented. The negatively charged dye eosin was found to be a good fluorescent marker for both the negatively charged phosphonic acids and the positively charged VX, and was chosen as the IDLIF visualization fluorescent dye. Separation and detection of VX, EMPA, and MPA in a simple-cross microchip were completed within less than a minute, and consumed only a 50 pL sample volume. A characteristic system peak that appeared in all IDLIF electropherograms served as an internal standard that increased the reliability of peak identification. The negative peak of both VX and the MPAs is in agreement with indirect detection theory and with previous reports in the literature. The LOD of VX and EMPA by IDLIF was 30 and 37 microM, respectively. Despite the fact that the detection sensitivity is relatively low, the rapid simultaneous on-chip analysis of both VX and its degradation products as well as the separation and detection of the MPA degradation products of both VX and GB, increases detection reliability and may present a choice when sensitivity is not critical compared with speed and simplicity of the assay. PMID:16703628

  20. Collider study on the loop-induced dark matter mediation

    NASA Astrophysics Data System (ADS)

    Tsai, Yuhsin

    2016-06-01

    Collider experiments are one of the most promising ways to constrain Dark Matter (DM) interactions. For DM couplings involving light mediators, especially for the loop-mediated interactions, a meaningful interpretation of the results requires to go beyond effective field theory. In this note we discuss the study of the magnetic dipole interacting DM, focusing on a model with anarchic dark flavor structure. By including the momentum-dependent form factors that mediate the coupling - given by the Dark Penguin - in collider processes, we study bounds from monophoton, diphoton, and non-pointing photon searches at the LHC. We also compare our results to constraints from the direct detection experiments.

  1. Direct and indirect influences of fate control belief, gambling expectancy bias, and self-efficacy on problem gambling and negative mood among Chinese college students: a multiple mediation analysis.

    PubMed

    Tang, Catherine So-Kum; Wu, Anise M S

    2010-12-01

    A multiple mediation model was proposed to integrate core concepts of the social axioms framework and the social cognitive theory in order to understand gambling behavior. It was hypothesized that the influence of general fate control belief on problem gambling and negative mood would be mediated by gambling-specific beliefs. Data from 773 Chinese college recreational gamblers were collected. The bootstrapping procedure was used to test the multiple mediation hypotheses. Significant indirect effects of fate control belief on problem gambling and negative mood through two gambling-specific mediators were found. Gambling expectancy bias was a more salient mediator than gambling self-efficacy. Fate control belief was also found to have a significant direct effect on negative mood. In general, a high level of general fate control belief was related to greater gambling expectancy bias and lower self-efficacy in resisting gambling, which were in turn related to problem gambling and negative mood. Limitations and implications of the study were discussed. PMID:20143258

  2. Apoptotic cells induce dendritic cell-mediated suppression via interferon-γ-induced IDO

    PubMed Central

    Williams, Charlotte A; Harry, Rachel A; McLeod, Julie D

    2008-01-01

    Dendritic cells (DC) are sensitive to their local environment and are affected by proximal cell death. This study investigated the modulatory effect of cell death on DC function. Monocyte-derived DC exposed to apoptotic Jurkat or primary T cells failed to induce phenotypic maturation of the DC and were unable to support CD4+ allogeneic T-cell proliferation compared with DC exposed to lipopolysaccharide (LPS) or necrotic cells. Apoptotic cells coincubated with LPS- or necrotic cell-induced mature DC significantly suppressed CD80, CD86 and CD83 and attenuated LPS-induced CD4+ T-cell proliferation. Reduced levels of interleukin-12 (IL-12), IL-10, IL-6, tumour necrosis factor-α and interferon-γ (IFN-γ) were found to be concomitant with the suppressive activity of apoptotic cells upon DC. Furthermore, intracellular staining confirmed IFN-γ expression by DC in association with apoptotic environments. The specific generation of IFN-γ by DC within apoptotic environments is suggestive of an anti-inflammatory role by the induction of indoleamine 2,3-dioxygenase (IDO). Both neutralization of IFN-γ and IDO blockade demonstrated a role for IFN-γ and IDO in the suppression of CD4+ T cells. Moreover, we demonstrate that IDO expression within the DC was found to be IFN-γ-dependent. Blocking transforming growth factor-β (TGF-β) also produced a partial release in T-cell proliferation. Our study strongly suggests that apoptosis-induced DC suppression is not an immunological null event and two prime mediators underpinning these functional effects are IFN-γ-induced IDO and TGF-β. PMID:18067553

  3. Wheel running alters patterns of uncontrollable stress-induced cfos mRNA expression in rat dorsal striatum direct and indirect pathways: a possible role for plasticity in adenosine receptors

    PubMed Central

    Clark, Peter J.; Ghasem, Parsa R.; Mika, Agnieszka; Day, Heidi E.; Herrera, Jonathan J.; Greenwood, Benjamin N.; Fleshner, Monika

    2014-01-01

    Emerging evidence indicates that adenosine is a major regulator of striatum activity, in part, through the antagonistic modulation of dopaminergic function. Exercise can influence adenosine and dopamine activity, which may subsequently promote plasticity in striatum adenosine and dopamine systems. Such changes could alter activity of medium spiny neurons and impact striatum function. The purpose of this study was two-fold. The first was to characterize the effect of long-term wheel running on adenosine 1 (A1R), adenosine 2A (A2AR), dopamine 1 (D1R), and dopamine 2 (D2R) receptor mRNA expression in adult rat dorsal and ventral striatum structures using in situ hybridization. The second was to determine if changes to adenosine and dopamine receptor mRNA from running are associated with altered cfos mRNA induction in dynorphin- (direct pathway) and enkephalin- (indirect pathway) expressing neurons of the dorsal striatum following stress exposure. We report that chronic running, as well as acute uncontrollable stress, reduced A1R and A2AR mRNA levels in the dorsal and ventral striatum. Running also modestly elevated D2R mRNA levels in striatum regions. Finally, stress-induced cfos was potentiated in dynorphin and attenuated in enkephalin expressing neurons of running rats. These data suggest striatum adenosine and dopamine systems are targets for neuroplasticity from exercise, which may contribute to changes in direct and indirect pathway activity. These findings may have implications for striatum mediated motor and cognitive processes, as well as exercise facilitated stress-resistance. PMID:25017571

  4. Quantum-size-induced phase transitions in quantum dots: Indirect-band gap GaAs nanostructures

    NASA Astrophysics Data System (ADS)

    Zunger, Alex; Luo, Jun-Wei; Franceschetti, Alberto

    2008-03-01

    Quantum nanostructures are often advertised as having stronger absorption than the bulk material from which they are made, to the potential benefit of nanotechnology. However, nanostructures made of direct gap materials such as GaAs can convert to indirect-gap, weakly-aborbing systems when the quantum size becomes small. This is the case for spherical GaAs dots of radius 15 å or less (about 1000 atoms) embedded in a wide-gap matrix. The nature of the transition: γ-to-X or γ-to-L is however, controversial. The distinction can not be made on the basis of electronic structure techniques that misrepresent the magnitude of the various competing effective mass tensors (e.g, LDA or GGA) or wavefunction coupling (e.g, tight-binding). Using a carefully fit screened pseudopotential method we show that the transition occurs from γ to X, and, more importantly, that the transition involves a finite V (γ-X) interband coupling, manifested as an ``anti-crossing'' between the confined electron states of GaAs as the dot size crosses 15 å. The physics of this reciprocal-space γ-X transition, as well as the real-space (type II) transition in GaAs/AlGaAs will be briefly discussed.

  5. Determination of nicotinyl pesticide residues in vegetables by micellar electrokinetic capillary chromatography with quantum dot indirect laser-induced fluorescence.

    PubMed

    Chen, Guan-Hua; Sun, Juan; Dai, Yong-Jia; Dong, Min

    2012-07-01

    A new assay was developed by use of micellar electrokinetic capillary chromatography with indirect LIF fluorescence for the determination of thiamethoxam, acetamiprid, and imidacloprid residues in vegetables, in which the cadmium telluride quantum dots (QDs) synthesized in aqueous phase were used as fluorescent background substance and their excitation and emission wavelengths matched with LIF detector by engineering their size. The factors that affected the peak height and the resolution were optimized. The running buffer was composed of 4.4 μM cadmium telluride QDs as fluorescent background substance, 40 mM borate and 60 mM SDS, and its pH was adjusted to 8.0. The separation voltage was 25 kV. Under the optimum conditions, the detection limits were 0.05, 0.01, and 0.009 mg/kg; the linear dynamic ranges were 0.5-30, 0.1-30, and 0.1-30 mg/L; and the average recoveries of spiked samples were 72.0-101.2, 74.0-106.7, and 77.8-105.1% for thiamethoxam, acetamiprid, and imidacloprid, respectively. The assay can meet the requirement of maximum residue limits to these three pesticides in the regulations of European Union and Japan, and has been applied for determining their residues in vegetables. PMID:22821497

  6. Probability of pipe failure in the reactor coolant loops of Combustion Engineering PWR Plants. Volume 3. Double-ended guillotine break indirectly induced by earthquakes

    SciTech Connect

    Ravindra, M.K.; Campbell, R.D.; Kennedy, R.P.; Banon, H.

    1985-01-01

    The requirements to design nuclear power plants for the effects of an instantaneous double-ended guillotine break (DEGB) of reactor coolant loop (RCL) piping have led to excessive design costs, interference of normal plant operation and maintenance, and unnecessary radiation exposure of plant maintenance personnel. This report describes an aspect of the NRC/Lawrence Livermore National Laboratory sponsored research program aimed at investigating whether the probability of DEGB in RCL Piping of nuclear power plants is acceptably small and the requirements to design for the DEGB effects (e.g., provision of pipe whip restraints) may be removed. This study estimated the probability of indirect DEGB in RCL piping as a consequence of seismic-induced structural failures within the containment of Combustion Engineering supplied pressurized water reactor nuclear power plants in the United States. The median probability of indirect DEGB was estimated to be in the range of 10/sup -6/ per year for older plants, and less than 10/sup -8/ per year for modern plants; using very conservative assumptions, the 90% subjective probability value (confidence) of P/sub DEGB/ was found to be less than 5 x 10/sup -5/ per year for older plants and less than 3 x 10/sup -7/ per year for modern plants.

  7. Probability of pipe failure in the reactor coolant loops of Babcock and Wilcox PWR plants. Volume 2. Guillotine break indirectly induced by earthquakes

    SciTech Connect

    Ravindra, M.K.; Campbell, R.D.; Kipp, T.R.; Sues, R.H.

    1985-07-01

    The requirements to design nuclear power plants for the effects of an instantaneous double-ended guillotine break (DEGB) of the reactor coolant loop (RCL) piping have led to excessive design costs, interference with normal plant operation and maintenance, and unnecessary radiation exposure of plant maintenance personnel. This report describes an aspect of the NRC/Lawrence Livermore National Laboratory sponsored research program aimed at exploring whether the probability of DEGB in RCL Piping of nuclear power plants is acceptably small and the requirements to design for the DEGB effects (e.g., provision of pipe whip restraints) may be removed. This study estimates the probability of indirect DEGB in RCL piping as a consequence of seismic-induced structural failures within the containment of Babcock and Wilcox supplied pressurized water reactor nuclear power plants in the United States. The median probability of indirect DEGB was estimated to range between 6 x 10/sup -11/ and 1 x 10/sup -7/ per year. Using very conservative assumptions, the 90% subjective probability value (confidence) of P/sub DEGB/ was found to be less than 1 x 10/sup -5/ per year. 19 refs., 19 figs., 11 tabs.

  8. Probability of pipe failure in the reactor coolant loop of Westinghouse PWR plants. Volume 3. Guillotine break indirectly induced by earthquakes

    SciTech Connect

    Ravindra, M.K.; Campbell, R.D.; Kennedy, R.P.; Banon, H.

    1985-02-01

    The requirements to design nuclear power plants for the effects of an instantaneous double-ended guillotine break (DEGB) of reactor coolant loop (RCL) piping have led to excessive design costs, interference of normal plant operation and maintenance, and unnecessary radiation exposure of plant maintenance personnel. This report describes an aspect of the NRC/Lawrence Livermore National Laboratory sponsored research program aimed at investigating whether the probability of DEGB in RCL piping of nuclear power plants is acceptably small and the requirements to design for the DEGB effects (e.g., provision of pipe whip restraints) may be removed. This study estimated the probability of indirect DEGB in RCL piping as a consequence of seismic-induced structural failures within the containment of Westinghouse supplied pressurized water reactor nuclear power plants in the United States. The median probability of indirect DEGB was estimated to be about 3x10/sup -6/ per year with a 10% to 90% subjective probability range approximately from 1x10/sup -7/ per year to 5x10/sup -5/ per year.

  9. Effects of indirect actions and oxygen on relative biological effectiveness: estimate of DSB induction and conversion induced by gamma rays and helium ions.

    PubMed

    Tsai, Ju-Ying; Chen, Fang-Hsin; Hsieh, Tsung-Yu; Hsiao, Ya-Yun

    2015-07-01

    Clustered DNA damage other than double-strand breaks (DSBs) can be detrimental to cells and can lead to mutagenesis or cell death. In addition to DSBs induced by ionizing radiation, misrepair of non-DSB clustered damage contributes extra DSBs converted from DNA misrepair via pathways for base excision repair and nucleotide excision repair. This study aimed to quantify the relative biological effectiveness (RBE) when DSB induction and conversion from non-DSB clustered damage misrepair were used as biological endpoints. The results showed that both linear energy transfer (LET) and indirect action had a strong impact on the yields for DSB induction and conversion. RBE values for DSB induction and maximum DSB conversion of helium ions (LET = 120 keV/μm) to (60)Co gamma rays were 3.0 and 3.2, respectively. These RBE values increased to 5.8 and 5.6 in the absence of interference of indirect action initiated by addition of 2-M dimethylsulfoxide. DSB conversion was ∼1-4% of the total non-DSB damage due to gamma rays, which was lower than the 10% estimate by experimental measurement. Five to twenty percent of total non-DSB damage due to helium ions was converted into DSBs. Hence, it may be possible to increase the yields of DSBs in cancerous cells through DNA repair pathways, ultimately enhancing cell killing. PMID:25902742

  10. Effects of indirect actions and oxygen on relative biological effectiveness: estimate of DSB induction and conversion induced by gamma rays and helium ions

    PubMed Central

    Tsai, Ju-Ying; Chen, Fang-Hsin; Hsieh, Tsung-Yu; Hsiao, Ya-Yun

    2015-01-01

    Clustered DNA damage other than double-strand breaks (DSBs) can be detrimental to cells and can lead to mutagenesis or cell death. In addition to DSBs induced by ionizing radiation, misrepair of non-DSB clustered damage contributes extra DSBs converted from DNA misrepair via pathways for base excision repair and nucleotide excision repair. This study aimed to quantify the relative biological effectiveness (RBE) when DSB induction and conversion from non-DSB clustered damage misrepair were used as biological endpoints. The results showed that both linear energy transfer (LET) and indirect action had a strong impact on the yields for DSB induction and conversion. RBE values for DSB induction and maximum DSB conversion of helium ions (LET = 120 keV/μm) to 60Co gamma rays were 3.0 and 3.2, respectively. These RBE values increased to 5.8 and 5.6 in the absence of interference of indirect action initiated by addition of 2-M dimethylsulfoxide. DSB conversion was ∼1–4% of the total non-DSB damage due to gamma rays, which was lower than the 10% estimate by experimental measurement. Five to twenty percent of total non-DSB damage due to helium ions was converted into DSBs. Hence, it may be possible to increase the yields of DSBs in cancerous cells through DNA repair pathways, ultimately enhancing cell killing. PMID:25902742

  11. p53-induced Gene 3 Mediates Cell Death Induced by Glutathione Peroxidase 3*

    PubMed Central

    Wang, Hui; Luo, Katherine; Tan, Lang-Zhu; Ren, Bao-Guo; Gu, Li-Qun; Michalopoulos, George; Luo, Jian-Hua; Yu, Yan P.

    2012-01-01

    Expression of glutathione peroxidase 3 (GPx3) is down-regulated in a variety of human malignancies. Both methylation and deletion of GPx3 gene underlie the alterations of GPx3 expression in prostate cancer. A strong correlation between the down-regulation of GPx3 expression and progression of prostate cancer and the suppression of prostate cancer xenografts in SCID mice by forced expression of GPx3 suggests a tumor suppression role of GPx3 in prostate cancer. However, the mechanism of GPx3-mediated tumor suppression remains unclear. In this report, GPx3 was found to interact directly with p53-induced gene 3 (PIG3). Forced overexpression of GPx3 in prostate cancer cell lines DU145 and PC3 as well as immortalized prostate epithelial cells RWPE-1 increased apoptotic cell death. Expression of GPx3x73c, a peroxidase-negative OPAL codon mutant, in DU145 and PC3 cells also increased cell death. The induced expression of GPx3 in DU145 and PC3 cells resulted in an increase in reactive oxygen species and caspase-3 activity. These activities were abrogated by either knocking down PIG3 or mutating the PIG3 binding motif in GPx3 or binding interference from a peptide corresponding to PIG3 binding motif in GPx3. In addition, UV-treated RWPE-1 cells underwent apoptotic death, which was partially prevented by knocking down GPx3 or PIG3, suggesting that GPx3-PIG3 signaling is critical for UV-induced apoptosis. Taken together, these results reveal a novel signaling pathway of GPx3-PIG3 in the regulation of cell death in prostate cancer. PMID:22461624

  12. Associational refuges among corals mediate impacts of a crown-of-thorns starfish Acanthaster planci outbreak. Indirect positive interactions in communities

    NASA Astrophysics Data System (ADS)

    Kayal, Mohsen; Lenihan, Hunter S.; Pau, Cédric; Penin, Lucie; Adjeroud, Mehdi

    2011-09-01

    Interactions among coral populations can moderate the impact of coral predator outbreaks, enhancing community resilience and recovery. This study used predator-exclusion cages and neighbour removals in a field experiment to test how indirect interactions between populations of three coral taxa, Acropora, Pocillopora, and Porites, influenced their survival during an outbreak of the crown-of-thorns starfish, Acanthaster planci, in Moorea, French Polynesia. High densities of corals enhanced survival by generating associational refuges: physical structures that impeded Acanthaster and protected corals, and by simple density-dependent prey dilution that reduced predation rates. Acanthaster showed feeding preferences, resulting in varying intensities of predation on corals, which (1) influenced the type and strength of the associational refuge among corals and (2) resulted in significant loss of the competitive dominants to the benefit of the competitive inferiors. The result was a set of indirect positive interactions (IPIs) that prevented Acanthaster from eradicating Acropora and may have enhanced Porites, a relatively weak competitor among corals. IPIs probably play a key role in many ecosystems, especially in coral reefs in which corals act as engineer species, to reduce impacts of perturbations and enhance community resilience. This study illustrates the importance of IPIs in community regulation with a new conceptual model.

  13. Tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge

    SciTech Connect

    Inaoka, Takeshi Furukawa, Takuro; Toma, Ryo; Yanagisawa, Susumu

    2015-09-14

    By means of a hybrid density-functional method, we investigate the tensile-strain effect of inducing the indirect-to-direct band-gap transition and reducing the band-gap energy of Ge. We consider [001], [111], and [110] uniaxial tensility and (001), (111), and (110) biaxial tensility. Under the condition of no normal stress, we determine both normal compression and internal strain, namely, relative displacement of two atoms in the primitive unit cell, by minimizing the total energy. We identify those strain types which can induce the band-gap transition, and evaluate the critical strain coefficient where the gap transition occurs. Either normal compression or internal strain operates unfavorably to induce the gap transition, which raises the critical strain coefficient or even blocks the transition. We also examine how each type of tensile strain decreases the band-gap energy, depending on its orientation. Our analysis clearly shows that synergistic operation of strain orientation and band anisotropy has a great influence on the gap transition and the gap energy.

  14. TRPV1 receptors mediate particulate matter-induced apoptosis.

    PubMed

    Agopyan, N; Head, J; Yu, S; Simon, S A

    2004-03-01

    Exposure to airborne particulate matter (PM) is a world-wide health problem mainly because it produces adverse cardiovascular and respiratory effects that frequently result in morbidity. Despite many years of epidemiological and basic research, the mechanisms underlying PM toxicity remain largely unknown. To understand some of these mechanisms, we measured PM-induced apoptosis and necrosis in normal human airway epithelial cells and sensory neurons from both wild-type mice and mice lacking TRPV1 receptors using Alexa Fluor 488-conjugated annexin V and propidium iodide labeling, respectively. Exposure of environmental PMs containing residual oil fly ash and ash from Mount St. Helens was found to induce apoptosis, but not necrosis, as a consequence of sustained calcium influx through TRPV1 receptors. Apoptosis was completely prevented by inhibiting TRPV1 receptors with capsazepine or by removing extracellular calcium or in sensory neurons from TRPV1(-/-) mice. Binding of either one of the PMs to the cell membrane induced a capsazepine-sensitive increase in cAMP. PM-induced apoptosis was augmented upon the inhibition of PKA. PKA inhibition on its own also induced apoptosis, thereby suggesting that this pathway may be endogenously protective against apoptosis. In summary, it was found that inhibiting TRPV1 receptors prevents PM-induced apoptosis, thereby providing a potential mechanism to reduce their toxicity. PMID:14633515

  15. Nitric oxide mediates bleomycin-induced angiogenesis and pulmonary fibrosis via regulation of VEGF.

    PubMed

    Iyer, Anand Krishnan V; Ramesh, Vani; Castro, Carlos A; Kaushik, Vivek; Kulkarni, Yogesh M; Wright, Clayton A; Venkatadri, Rajkumar; Rojanasakul, Yon; Azad, Neelam

    2015-11-01

    Pulmonary fibrosis is a progressive lung disease hallmarked by increased fibroblast proliferation, amplified levels of extracellular matrix deposition and increased angiogenesis. Although dysregulation of angiogenic mediators has been implicated in pulmonary fibrosis, the specific rate-limiting angiogenic markers involved and their role in the progression of pulmonary fibrosis remains unclear. We demonstrate that bleomycin treatment induces angiogenesis, and inhibition of the central angiogenic mediator VEGF using anti-VEGF antibody CBO-P11 significantly attenuates bleomycin-induced pulmonary fibrosis in vivo. Bleomycin-induced nitric oxide (NO) was observed to be the key upstream regulator of VEGF via the PI3k/Akt pathway. VEGF regulated other important angiogenic proteins including PAI-1 and IL-8 in response to bleomycin exposure. Inhibition of NO and VEGF activity significantly mitigated bleomycin-induced angiogenic and fibrogenic responses. NO and VEGF are key mediators of bleomycin-induced pulmonary fibrosis, and could serve as important targets against this debilitating disease. Overall, our data suggests an important role for angiogenic mediators in the pathogenesis of bleomycin-induced pulmonary fibrosis. PMID:25919965

  16. JAK2-STAT3 signaling pathway mediates thrombin-induced proinflammatory actions of microglia in vitro.

    PubMed

    Huang, Chengfang; Ma, Rong; Sun, Shenggang; Wei, Guirong; Fang, Yuan; Liu, Rengang; Li, Gang

    2008-11-15

    The present study shows that JAK2-STAT3 inflammatory signaling mediates thrombin-stimulated microglia activation. In rat primary microglia, thrombin rapidly activated JAK2 and induced phosphorylation of STAT3. In addition, thrombin increased transcription of the inflammation-associated genes tumor necrosis factor (TNF)-alpha, inducible nitric oxide synthase (iNOS), production of TNF-alpha, NO and induced neurodegeneration of dopaminergic neurons in mesencephalic cultures. AG490, a JAK inhibitor, markedly reduced activation of JAK2 and STAT3 in thrombin-treated microglia. AG490 also inhibited thrombin-induced transcription and expression of TNF-alpha, iNOS and/or NO release, moreover rescued dopaminergic neurons. These results suggest that JAK2-STAT3 signaling pathway plays a critical role in mediating thrombin-induced activation of microglia and degeneration of dopaminergic neurons. PMID:18710787

  17. The endothelial glycocalyx mediates shear-induced changes in hydraulic conductivity

    PubMed Central

    Lopez-Quintero, Sandra V.; Amaya, Ronny; Pahakis, Manolis; Tarbell, John M.

    2009-01-01

    Recent in vitro and in vivo studies have reported fluid shear stress-induced increases in endothelial layer hydraulic conductivity (Lp) that are mediated by an increased production of nitric oxide (NO). Other recent studies have shown that NO induction by shear stress is mediated by the glycocalyx that decorates the surface of endothelial cells. Here we find that a selective depletion of the major components of the glycocalyx with enzymes can block the shear stress-induced response of Lp. Heparinase and hyaluronidase block shear-induced increases in Lp, which is consistent with their effects on NO production. But chondroitinase, which does not suppress shear-induced NO production, also inhibits shear-induced Lp. A further surprise is that treatment with the general proteolytic enzyme pronase does not suppress the shear Lp response. We also find that heparinase does not alter baseline Lp significantly, whereas chondroitinase, hyaluronidase, and pronase increase it significantly. PMID:19286951

  18. Chorioamnionitis-induced fetal gut injury is mediated by direct gut exposure of inflammatory mediators or by lung inflammation

    PubMed Central

    Wolfs, Tim G. A. M.; Kramer, Boris W.; Thuijls, Geertje; Kemp, Matthew W.; Saito, Masatoshi; Willems, Monique G. M.; Senthamarai-Kannan, Paranthaman; Newnham, John P.; Jobe, Alan H.

    2014-01-01

    Intra-amniotic exposure to proinflammatory agonists causes chorioamnionitis and fetal gut inflammation. Fetal gut inflammation is associated with mucosal injury and impaired gut development. We tested whether this detrimental inflammatory response of the fetal gut results from a direct local (gut derived) or an indirect inflammatory response mediated by the chorioamnion/skin or lung, since these organs are also in direct contact with the amniotic fluid. The gastrointestinal tract was isolated from the respiratory tract and the amnion/skin epithelia by fetal surgery in time-mated ewes. Lipopolysaccharide (LPS) or saline (controls) was selectively infused in the gastrointestinal tract, trachea, or amniotic compartment at 2 or 6 days before preterm delivery at 124 days gestation (term 150 days). Gastrointestinal and intratracheal LPS exposure caused distinct inflammatory responses in the fetal gut. Inflammatory responses could be distinguished by the influx of leukocytes (MPO+, CD3+, and FoxP3+ cells), tumor necrosis factor-α, and interferon-γ expression and differential upregulation of mRNA levels for Toll-like receptor 1, 2, 4, and 6. Fetal gut inflammation after direct intestinal LPS exposure resulted in severe loss of the tight junctional protein zonula occludens protein 1 (ZO-1) and increased mitosis of intestinal epithelial cells. Inflammation of the fetal gut after selective LPS instillation in the lungs caused only mild disruption of ZO-1, loss in epithelial cell integrity, and impaired epithelial differentiation. LPS exposure of the amnion/skin epithelia did not result in gut inflammation or morphological, structural, and functional changes. Our results indicate that the detrimental consequences of chorioamnionitis on fetal gut development are the combined result of local gut and lung-mediated inflammatory responses. PMID:24458021

  19. Chorioamnionitis-induced fetal gut injury is mediated by direct gut exposure of inflammatory mediators or by lung inflammation.

    PubMed

    Wolfs, Tim G A M; Kramer, Boris W; Thuijls, Geertje; Kemp, Matthew W; Saito, Masatoshi; Willems, Monique G M; Senthamarai-Kannan, Paranthaman; Newnham, John P; Jobe, Alan H; Kallapur, Suhas G

    2014-03-01

    Intra-amniotic exposure to proinflammatory agonists causes chorioamnionitis and fetal gut inflammation. Fetal gut inflammation is associated with mucosal injury and impaired gut development. We tested whether this detrimental inflammatory response of the fetal gut results from a direct local (gut derived) or an indirect inflammatory response mediated by the chorioamnion/skin or lung, since these organs are also in direct contact with the amniotic fluid. The gastrointestinal tract was isolated from the respiratory tract and the amnion/skin epithelia by fetal surgery in time-mated ewes. Lipopolysaccharide (LPS) or saline (controls) was selectively infused in the gastrointestinal tract, trachea, or amniotic compartment at 2 or 6 days before preterm delivery at 124 days gestation (term 150 days). Gastrointestinal and intratracheal LPS exposure caused distinct inflammatory responses in the fetal gut. Inflammatory responses could be distinguished by the influx of leukocytes (MPO(+), CD3(+), and FoxP3(+) cells), tumor necrosis factor-α, and interferon-γ expression and differential upregulation of mRNA levels for Toll-like receptor 1, 2, 4, and 6. Fetal gut inflammation after direct intestinal LPS exposure resulted in severe loss of the tight junctional protein zonula occludens protein 1 (ZO-1) and increased mitosis of intestinal epithelial cells. Inflammation of the fetal gut after selective LPS instillation in the lungs caused only mild disruption of ZO-1, loss in epithelial cell integrity, and impaired epithelial differentiation. LPS exposure of the amnion/skin epithelia did not result in gut inflammation or morphological, structural, and functional changes. Our results indicate that the detrimental consequences of chorioamnionitis on fetal gut development are the combined result of local gut and lung-mediated inflammatory responses. PMID:24458021

  20. Mitochondrion-mediated apoptosis induced by photofrin-PDT

    NASA Astrophysics Data System (ADS)

    Wu, Yunxia; Xing, Da

    2007-05-01

    Apoptosis is an important cellular event that plays a key role in pathogeny and therapy of many diseases. The mechanisms of the initiation and regulation of PDT-induced apoptosis are complex. Some PDT-associated apoptosis pathways involved plasma membrane death receptors, mitochondria, lysosomes and endoplasmic reticulum (ER). In order to determine the apoptosis pathway induced by Photofrin-PDT, we used fluorescence resonance energy transfer (FRET) technique and probe SCAT3 to monitor the dynamics of caspase-3 activation after PDT treatment and also measured caspase-8 activity. With laser scanning confocal microscopy, we found that Photofrin were localized primarily in mitochondria, the primary targets of Photofrin-PDT. Formation of mitochondrial reactive oxygen species (ROS) was detected within minutes after PDT treatment. This was followed by mitochondrial membrane potential (ΔΨm), cytochrome c release, caspase-9 activity, caspase-3 activity and apoptosis. After PDT treatment, caspase-3 was activated rapidly while caspase-8 remained inactivated. Our results indicated that PDT-induced apoptosis was initiated from mitochondria pathway and independent of caspase-8 activation. The activation of caspase-3 by PDT started 20 minutes after treatment and completed in about 15 minutes. PDT-induced apoptosis is directly initiated from mitochondria pathway and not involved in the death receptors-dependent pathway. Our results demonstrated that FRET could be an effective tool to determine PDT-induced apoptosis and other cell death mechanism.

  1. Dendritic cells and alveolar macrophages mediate IL-13–induced airway inflammation and chemokine production

    PubMed Central

    Crapster-Pregont, Margaret; Yeo, Janice; Sanchez, Raquel L.; Kuperman, Douglas A.

    2013-01-01

    Background IL-13 in the airway induces pathologies that are highly characteristic of asthma, including mucus metaplasia, airway hyperreactivity (AHR), and airway inflammation. As such, it is important to identify the IL-13–responding cell types that mediate each of the above pathologies. For example, IL-13’s effects on epithelium contribute to mucus metaplasia and AHR. IL-13’s effects on smooth muscle also contribute to AHR. However, it has been difficult to identify the cell types that mediate IL-13–induced airway inflammation. Objective We sought to determine which cell types mediate IL-13–induced airway inflammation. Methods We treated the airways of mice with IL-13 alone or in combination with IFN-γ. We associated the inhibitory effect of IFN-γ on IL-13–induced airway inflammation and chemokine production with cell types in the lung that coexpress IL-13 and IFN-γ receptors. We then evaluated IL-13–induced responses in CD11c promoter–directed diphtheria toxin receptor–expressing mice that were depleted of both dendritic cells and alveolar macrophages and in CD11b promoter–directed diphtheria toxin receptor– expressing mice that were depleted of dendritic cells. Results Dendritic cell and alveolar macrophage depletion protected mice from IL-13–induced airway inflammation and CCL11, CCL24, CCL22, and CCL17 chemokine production. Preferential depletion of dendritic cells protected mice from IL-13–induced airway inflammation and CCL22 and CCL17 chemokine production but not from IL-13–induced CCL11 and CCL24 chemokine production. In either case mice were not protected from IL-13–induced AHR and mucus metaplasia. Conclusions Pulmonary dendritic cells and alveolar macrophages mediate IL-13–induced airway inflammation and chemokine production. (J Allergy Clin Immunol 2012;129:1621-7.) PMID:22365581

  2. Application of the solid polymer electrolyte method to organic electrochemistry; 17: Indirect electrochemical debromination using viologens as microscopic phase-transfer mediators

    SciTech Connect

    Inaba, Minoru; Ogumi, Zempachi; Takehara, Zenichiro . Division of Energy and Hydrocarbon Chemistry)

    1994-10-01

    Solid polymer electrolyte composite electrodes have been extensively studied for use in water electrolyzers, brine electrolyzers, and fuel cells. Solid polymer electrolyte (SPE[reg sign]) composite electrodes using a perfluorinated ion-exchange membrane (Nafion[reg sign]), which is known to be microscopically separated into hydrophilic and hydrophobic domains, were prepared. Various N,N[prime]-dialkyl-4-4[prime]-bipyridinium salts (viologens) were incorporated in the SPE composite electrodes as phase transfer mediators. Electrochemical debromination of meso-1,2-dibromo-1,2-diphenylethane was carried out on the SPE composite electrodes. The results were compared with those obtained in an emulsion system consisting of water and dichloromethane. Of the viologen compounds tested, propyl viologen was the most effective mediator for the SPE composite electrode, while octyl viologen dibromide was the most effective mediator in the emulsion system. The active species for the debromination in the emulsion system was shown to be a doubly reduced neutral form of viologen that was generated by the disproportionation of cation radicals. The disproportionation constant, K[sub d], of octyl viologen cation radical in a two-phase system consisting of water and dichloromethane was estimated to be 809. The reaction mechanism on the SPE composite electrode was discussed, and it was considered that the active species was generated by disproportionation at the microscopically heterogeneous interface between the hydrophilic and hydrophobic domains of the Nafion.

  3. Hep-2 cell based indirect immunofluorescence assay for antinuclear antibodies as a potential diagnosis of drug-induced autoimmunity in nonclinical toxicity testing.

    PubMed

    Hong, Min; Ma, Ben; Lin, Zhi; Zhou, Xiaobing; Geng, Xingchao; Shen, Lianzhong; Li, Bo

    2015-03-01

    Antinuclear antibodies (ANAs) are important biomarkers in the diagnosis of autoimmune diseases in humans; however, the diagnostic performance of ANA in nonclinical safety studies are not well understood. Here, we studied the use of ANAs as potential nonclinical biomarkers for drug-induced autoimmunity (DIA) using a Hep-2 based indirect immunofluorescence assay (IFA). Initially, MRL-fas(lpr)/J mice and HgCl₂-treated rats were used as SLE-positive models. Serum samples obtained from 94 normal mice or 204 normal rats aged one to four months served as the negative control. The IFA effectively distinguished ANAs-positive samples in both species with a cut-off titer of 1:100. Brown Norway rats were treated with 450 mg/kg D-penicillamine for 30 consecutive days. ANAs were generated and corresponded with DIA development. Human Hep-2 cells, mice Neuro 2A cells, and Chinese Hamster Lung cells served as antigen from different species, which were found cross-reactive with ANA-positive serum samples from mice, rats, and humans without any differences in diagnosis. This methodology showed no species-specificity for ANA detection. Furthermore, we found approximately 20 percentage of the mice aged seven to eight months demonstrated age-related ANAs, which was consistent with humans. Overall, our findings demonstrated the use of ANA detection using IFA in the nonclinical diagnosis of murine drug-induced autoimmunity, and age-related ANAs should be considered when aged animals are used. PMID:25455225

  4. Octopamine mediates starvation-induced hyperactivity in adult Drosophila

    PubMed Central

    Yang, Zhe; Yu, Yue; Zhang, Vivian; Tian, Yinjun; Qi, Wei; Wang, Liming

    2015-01-01

    Starved animals often exhibit elevated locomotion, which has been speculated to partly resemble foraging behavior and facilitate food acquisition and energy intake. Despite its importance, the neural mechanism underlying this behavior remains unknown in any species. In this study we confirmed and extended previous findings that starvation induced locomotor activity in adult fruit flies Drosophila melanogaster. We also showed that starvation-induced hyperactivity was directed toward the localization and acquisition of food sources, because it could be suppressed upon the detection of food cues via both central nutrient-sensing and peripheral sweet-sensing mechanisms, via induction of food ingestion. We further found that octopamine, the insect counterpart of vertebrate norepinephrine, as well as the neurons expressing octopamine, were both necessary and sufficient for starvation-induced hyperactivity. Octopamine was not required for starvation-induced changes in feeding behaviors, suggesting independent regulations of energy intake behaviors upon starvation. Taken together, our results establish a quantitative behavioral paradigm to investigate the regulation of energy homeostasis by the CNS and identify a conserved neural substrate that links organismal metabolic state to a specific behavioral output. PMID:25848004

  5. Ceramide Production Mediates Aldosterone-Induced Human Umbilical Vein Endothelial Cell (HUVEC) Damages

    PubMed Central

    Zhang, Yumei; Pan, Yu; Bian, Zhixiang; Chen, Peihua; Zhu, Shijian; Gu, Huiyi; Guo, Liping; Hu, Chun

    2016-01-01

    Here, we studied the underlying mechanism of aldosterone (Aldo)-induced vascular endothelial cell damages by focusing on ceramide. We confirmed that Aldo (at nmol/L) inhibited human umbilical vein endothelial cells (HUVEC) survival, and induced considerable cell apoptosis. We propose that ceramide (mainly C18) production might be responsible for Aldo-mediated damages in HUVECs. Sphingosine-1-phosphate (S1P), an anti-ceramide lipid, attenuated Aldo-induced ceramide production and following HUVEC damages. On the other hand, the glucosylceramide synthase (GCS) inhibitor PDMP or the ceramide (C6) potentiated Aldo-induced HUVEC apoptosis. Eplerenone, a mineralocorticoid receptor (MR) antagonist, almost completely blocked Aldo-induced C18 ceramide production and HUVEC damages. Molecularly, ceramide synthase 1 (CerS-1) is required for C18 ceramide production by Aldo. Knockdown of CerS-1 by targeted-shRNA inhibited Aldo-induced C18 ceramide production, and protected HUVECs from Aldo. Reversely, CerS-1 overexpression facilitated Aldo-induced C18 ceramide production, and potentiated HUVEC damages. Together, these results suggest that C18 ceramide production mediates Aldo-mediated HUVEC damages. MR and CerS-1 could be the two signaling molecule regulating C18 ceramide production by Aldo. PMID:26788916

  6. Interleukin-17 mediated inflammatory responses are required for ultraviolet radiation-induced immune suppression.

    PubMed

    Li, Hui; Prasad, Ram; Katiyar, Santosh K; Yusuf, Nabiha; Elmets, Craig A; Xu, Hui

    2015-01-01

    Ultraviolet radiation (UVR) induces immunosuppression and is a major factor for development of skin cancer. Numerous efforts have been made to determine mechanisms for UVR-induced immunosuppression and to develop strategies for prevention and treatment of UVR-induced cancers. In the current study, we use IL-17 receptor (IL-17R) deficient mice to examine whether IL-17 mediated responses have a role in UVB (290-320)-induced immunosuppression of contact hypersensitivity responses. Results demonstrate that IL-17 mediated responses are required for UVB-induced immunosuppression of contact hypersensitivity responses. The systemic immune suppression and development of regulatory T cells are inhibited in UVB-treated IL-17R deficient mice compared to wild-type animals. The deficiency in IL-17R inhibits the infiltration and development of a tolerogenic myeloid cell population in UVB-treated skin, which expresses CD11b and Gr-1 and produces reactive oxygen species. We speculate that the development of the tolerogenic myeloid cells is dependent on IL-17-induced chemokines and inflammatory mediators in UVB-treated skin. The inhibition of the tolerogenic myeloid cells may be attributed to the suppression of regulatory T cells in UVR-treated IL-17R(-/-) mice. The findings may be exploited to new strategies for prevention and treatment of UVR-induced skin diseases and cancers. PMID:25250896

  7. Cocaine induces astrocytosis through ER stress-mediated activation of autophagy.

    PubMed

    Periyasamy, Palsamy; Guo, Ming-Lei; Buch, Shilpa

    2016-08-01

    Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation. PMID:27337297

  8. Heptachlor induced mitochondria-mediated cell death via impairing electron transport chain complex III

    SciTech Connect

    Hong, Seokheon; Kim, Joo Yeon; Hwang, Joohyun; Shin, Ki Soon; Kang, Shin Jung

    2013-08-09

    Highlights: •Heptachlor inhibited mitochondrial electron transport chain complex III activity. •Heptachlor promoted generation of reactive oxygen species. •Heptachlor induced Bax activation. •Heptachlor induced mitochondria-mediated and caspase-dependent apoptosis. -- Abstract: Environmental toxins like pesticides have been implicated in the pathogenesis of Parkinson’s disease (PD). Epidemiological studies suggested that exposures to organochlorine pesticides have an association with an increased PD risk. In the present study, we examined the mechanism of toxicity induced by an organochlorine pesticide heptachlor. In a human dopaminergic neuroblastoma SH-SY5Y cells, heptachlor induced both morphological and functional damages in mitochondria. Interestingly, the compound inhibited mitochondrial electron transport chain complex III activity. Rapid generation of reactive oxygen species and the activation of Bax were then detected. Subsequently, mitochondria-mediated, caspase-dependent apoptosis followed. Our results raise a possibility that an organochlorine pesticide heptachlor can act as a neurotoxicant associated with PD.

  9. Dexamethasone-induced autophagy mediates muscle atrophy through mitochondrial clearance

    PubMed Central

    Troncoso, Rodrigo; Paredes, Felipe; Parra, Valentina; Gatica, Damián; Vásquez-Trincado, César; Quiroga, Clara; Bravo-Sagua, Roberto; López-Crisosto, Camila; Rodriguez, Andrea E; Oyarzún, Alejandra P; Kroemer, Guido; Lavandero, Sergio

    2014-01-01

    Glucocorticoids, such as dexamethasone, enhance protein breakdown via ubiquitin–proteasome system. However, the role of autophagy in organelle and protein turnover in the glucocorticoid-dependent atrophy program remains unknown. Here, we show that dexamethasone stimulates an early activation of autophagy in L6 myotubes depending on protein kinase, AMPK, and glucocorticoid receptor activity. Dexamethasone increases expression of several autophagy genes, including ATG5, LC3, BECN1, and SQSTM1 and triggers AMPK-dependent mitochondrial fragmentation associated with increased DNM1L protein levels. This process is required for mitophagy induced by dexamethasone. Inhibition of mitochondrial fragmentation by Mdivi-1 results in disrupted dexamethasone-induced autophagy/mitophagy. Furthermore, Mdivi-1 increases the expression of genes associated with the atrophy program, suggesting that mitophagy may serve as part of the quality control process in dexamethasone-treated L6 myotubes. Collectively, these data suggest a novel role for dexamethasone-induced autophagy/mitophagy in the regulation of the muscle atrophy program. PMID:24897381

  10. Fructokinase activity mediates dehydration-induced renal injury.

    PubMed

    Roncal Jimenez, Carlos A; Ishimoto, Takuji; Lanaspa, Miguel A; Rivard, Christopher J; Nakagawa, Takahiko; Ejaz, A Ahsan; Cicerchi, Christina; Inaba, Shinichiro; Le, MyPhuong; Miyazaki, Makoto; Glaser, Jason; Correa-Rotter, Ricardo; González, Marvin A; Aragón, Aurora; Wesseling, Catharina; Sánchez-Lozada, Laura G; Johnson, Richard J

    2014-08-01

    The epidemic of chronic kidney disease in Nicaragua (Mesoamerican nephropathy) has been linked with recurrent dehydration. Here we tested whether recurrent dehydration may cause renal injury by activation of the polyol pathway, resulting in the generation of endogenous fructose in the kidney that might subsequently induce renal injury via metabolism by fructokinase. Wild-type and fructokinase-deficient mice were subjected to recurrent heat-induced dehydration. One group of each genotype was provided water throughout the day and the other group was hydrated at night, after the dehydration. Both groups received the same total hydration in 24 h. Wild-type mice that received delayed hydration developed renal injury, with elevated serum creatinine, increased urinary NGAL, proximal tubular injury, and renal inflammation and fibrosis. This was associated with activation of the polyol pathway, with increased renal cortical sorbitol and fructose levels. Fructokinase-knockout mice with delayed hydration were protected from renal injury. Thus, recurrent dehydration can induce renal injury via a fructokinase-dependent mechanism, likely from the generation of endogenous fructose via the polyol pathway. Access to sufficient water during the dehydration period can protect mice from developing renal injury. These studies provide a potential mechanism for Mesoamerican nephropathy. PMID:24336030

  11. Cyclin C mediates stress-induced mitochondrial fission and apoptosis

    PubMed Central

    Wang, Kun; Yan, Ruilan; Cooper, Katrina F.; Strich, Randy

    2015-01-01

    Mitochondria are dynamic organelles that undergo constant fission and fusion cycles. In response to cellular damage, this balance is shifted dramatically toward fission. Cyclin C–Cdk8 kinase regulates transcription of diverse gene sets. Using knockout mouse embryonic fibroblasts (MEFs), we demonstrate that cyclin C directs the extensive mitochondrial scission induced by the anticancer drug cisplatin or oxidative stress. This activity is independent of transcriptional regulation, as Cdk8 is not required for this activity. Furthermore, adding purified cyclin C to unstressed permeabilized MEF cultures induced complete mitochondrial fragmentation that was dependent on the fission factors Drp1 and Mff. To regulate fission, a portion of cyclin C translocates from the nucleus to the cytoplasm, where it associates with Drp1 and is required for its enhanced mitochondrial activity in oxidatively stressed cells. In addition, although HeLa cells regulate cyclin C in a manner similar to MEF cells, U2OS osteosarcoma cultures display constitutively cytoplasmic cyclin C and semifragmented mitochondria. Finally, cyclin C, but not Cdk8, is required for loss of mitochondrial outer membrane permeability and apoptosis in cells treated with cisplatin. In conclusion, this study suggests that cyclin C connects stress-induced mitochondrial hyperfission and programmed cell death in mammalian cells. PMID:25609094

  12. Bioechnology of indirect liquefaction

    SciTech Connect

    Datta, R.; Jain, M.K.; Worden, R.M.; Grethlein, A.J.; Soni, B.; Zeikus, J.G.; Grethlein, H.

    1990-05-07

    The project on biotechnology of indirect liquefaction was focused on conversion of coal derived synthesis gas to liquid fuels using a two-stage, acidogenic and solventogenic, anaerobic bioconversion process. The acidogenic fermentation used a novel and versatile organism, Butyribacterium methylotrophicum, which was fully capable of using CO as the sole carbon and energy source for organic acid production. In extended batch CO fermentations the organism was induced to produce butyrate at the expense of acetate at low pH values. Long-term, steady-state operation was achieved during continuous CO fermentations with this organism, and at low pH values (a pH of 6.0 or less) minor amounts of butanol and ethanol were produced. During continuous, steady-state fermentations of CO with cell recycle, concentrations of mixed acids and alcohols were achieved (approximately 12 g/l and 2 g/l, respectively) which are high enough for efficient conversion in stage two of the indirect liquefaction process. The metabolic pathway to produce 4-carbon alcohols from CO was a novel discovery and is believed to be unique to our CO strain of B. methylotrophicum. In the solventogenic phase, the parent strain ATCC 4259 of Clostridium acetobutylicum was mutagenized using nitrosoguanidine and ethyl methane sulfonate. The E-604 mutant strain of Clostridium acetobutylicum showed improved characteristics as compared to parent strain ATCC 4259 in batch fermentation of carbohydrates.

  13. Phosphoinositide-mediated oligomerization of a defensin induces cell lysis

    PubMed Central

    Poon, Ivan KH; Baxter, Amy A; Lay, Fung T; Mills, Grant D; Adda, Christopher G; Payne, Jennifer AE; Phan, Thanh Kha; Ryan, Gemma F; White, Julie A; Veneer, Prem K; van der Weerden, Nicole L; Anderson, Marilyn A; Kvansakul, Marc; Hulett, Mark D

    2014-01-01

    Cationic antimicrobial peptides (CAPs) such as defensins are ubiquitously found innate immune molecules that often exhibit broad activity against microbial pathogens and mammalian tumor cells. Many CAPs act at the plasma membrane of cells leading to membrane destabilization and permeabilization. In this study, we describe a novel cell lysis mechanism for fungal and tumor cells by the plant defensin NaD1 that acts via direct binding to the plasma membrane phospholipid phosphatidylinositol 4,5-bisphosphate (PIP2). We determined the crystal structure of a NaD1:PIP2 complex, revealing a striking oligomeric arrangement comprising seven dimers of NaD1 that cooperatively bind the anionic headgroups of 14 PIP2 molecules through a unique ‘cationic grip’ configuration. Site-directed mutagenesis of NaD1 confirms that PIP2-mediated oligomerization is important for fungal and tumor cell permeabilization. These observations identify an innate recognition system by NaD1 for direct binding of PIP2 that permeabilizes cells via a novel membrane disrupting mechanism. DOI: http://dx.doi.org/10.7554/eLife.01808.001 PMID:24692446

  14. Lipid membrane-mediated attraction between curvature inducing objects.

    PubMed

    van der Wel, Casper; Vahid, Afshin; Šarić, Anđela; Idema, Timon; Heinrich, Doris; Kraft, Daniela J

    2016-01-01

    The interplay of membrane proteins is vital for many biological processes, such as cellular transport, cell division, and signal transduction between nerve cells. Theoretical considerations have led to the idea that the membrane itself mediates protein self-organization in these processes through minimization of membrane curvature energy. Here, we present a combined experimental and numerical study in which we quantify these interactions directly for the first time. In our experimental model system we control the deformation of a lipid membrane by adhering colloidal particles. Using confocal microscopy, we establish that these membrane deformations cause an attractive interaction force leading to reversible binding. The attraction extends over 2.5 times the particle diameter and has a strength of three times the thermal energy (-3.3 kBT). Coarse-grained Monte-Carlo simulations of the system are in excellent agreement with the experimental results and prove that the measured interaction is independent of length scale. Our combined experimental and numerical results reveal membrane curvature as a common physical origin for interactions between any membrane-deforming objects, from nanometre-sized proteins to micrometre-sized particles. PMID:27618764

  15. Inflammasomes are important mediators of cyclophosphamide-induced bladder inflammation.

    PubMed

    Hughes, Francis M; Vivar, Nivardo P; Kennis, James G; Pratt-Thomas, Jeffery D; Lowe, Danielle W; Shaner, Brooke E; Nietert, Paul J; Spruill, Laura S; Purves, J Todd

    2014-02-01

    Bladder inflammation (cystitis) underlies numerous bladder pathologies and is elicited by a plethora of agents such as urinary tract infections, bladder outlet obstruction, chemotherapies, and catheters. Pattern recognition receptors [Toll-like receptors (TLRs) and Nod-like receptors (NLRs)] that recognize pathogen- and/or damage-associated molecular patterns (PAMPs and/or DAMPs, respectively) are key components of the innate immune system that coordinates the production (TLRs) and maturation (NLRs) of proinflammatory IL-1β. Despite multiple studies of TLRs in the bladder, none have investigated NLRs beyond one small survey. We now demonstrate that NLRP3 and NLRC4, and their binding partners apoptosis-associated speck-like protein containing a COOH-terminal caspase recruitment domain (ASC) and NLR family apoptosis inhibitory protein (NAIP), are expressed in the bladder and localized predominantly to the urothelia. Activated NLRs form inflammasomes that activate caspase-1. Placement of a NLRP3- or NLRC4-activating PAMP or NLRP3-activating DAMPs into the lumen of the bladder stimulated caspase-1 activity. To investigate inflammasomes in vivo, we induced cystitis with cyclophosphamide (CP, 150 mg/kg ip) in the presence or absence of the inflammasome inhibitor glyburide. Glyburide completely blocked CP-induced activation of caspase-1 and the production of IL-1β at 4 h. At 24 h, glyburide reduced two markers of inflammation by 30-50% and reversed much of the inflammatory morphology. Furthermore, glyburide reversed changes in bladder physiology (cystometry) induced by CP. In conclusion, NLRs/inflammasomes are present in the bladder urothelia and respond to DAMPs and PAMPs, whereas NLRP3 inhibition blocks bladder dysfunction in the CP model. The coordinated response of NLRs and TLRs in the urothelia represents a first-line innate defense that may provide an important target for pharmacological intervention. PMID:24285499

  16. Biocontrol agents-mediated suppression of oxalic acid induced cell death during Sclerotinia sclerotiorum-pea interaction.

    PubMed

    Jain, Akansha; Singh, Akanksha; Singh, Surendra; Sarma, Birinchi Kumar; Singh, Harikesh Bahadur

    2015-05-01

    Oxalic acid (OA) is an important pathogenic factor during early Sclerotinia sclerotiorum-host interaction and might work by reducing hydrogen peroxide production (H2 O2 ). In the present investigation, oxalic acid-induced cell death in pea was studied. Pea plants treated with biocontrol agents (BCAs) viz., Pseudomonas aeruginosa PJHU15, Bacillus subtilis BHHU100, and Trichoderma harzianum TNHU27 either singly and/or in consortium acted on S. sclerotiorum indirectly by enabling plants to inhibit the OA-mediated suppression of oxidative burst via induction of H2 O2 . Our results showed that BCA treated plants upon treatment with culture filtrate of the pathogen, conferred the resistance via. significantly decreasing relative cell death of pea against S. sclerotiorum compared to control plants without BCA treatment but treated with the culture filtrate of the pathogen. The results obtained from the present study indicate that the microbes especially in consortia play significant role in protection against S. sclerotiorum by modulating oxidative burst and partially enhancing tolerance by increasing the H2 O2 generation, which is otherwise suppressed by OA produced by the pathogen. PMID:24920251

  17. Oxaliplatin-induced immune-mediated cytopenias: a case report and literature review.

    PubMed

    Forcello, Nicholas P; Khubchandani, Sapna; Patel, Shrina J; Brahaj, Driola

    2015-04-01

    Oxaliplatin is a third-generation platinum antineoplastic agent that commonly causes diarrhea, nausea, vomiting, myelosuppression, and peripheral neuropathy. Less common adverse effects that are increasingly being reported include acute immune-mediated thrombocytopenia, hemolytic anemia, and pancytopenia. Here, we report a patient case of suspected oxaliplatin-induced immune-mediated thrombocytopenia and a thorough literature evaluation of acute oxaliplatin-induced immune-mediated thrombocytopenia, hemolytic anemia, and pancytopenia that has yet to be reported until now. There have been 39 previously published reports of these cytopenic events with a median number of 16 treatment cycles prior to presentation. Patients experiencing unusual signs and symptoms such as chills, rigors, fever, back pain, abdominal pain, ecchymosis, hematemesis, hematuria, dark urine, hematochezia, petechiae, epistaxis, or mental status changes during or shortly after an oxaliplatin infusion should have complete blood counts ordered and evaluated promptly. PMID:24500808

  18. URBAN PARTICLE-INDUCED PULMONARY ARTERY CONSTRUCTION IS MEDIATED BY SUPEROXIDE PRODUCTION

    EPA Science Inventory

    URBAN PARTICLE-INDUCED PULMONARY ARTERY CONSTRICTION IS MEDIATED BY SUPEROXIDE PRODUCTION.Jacqueline D. Carter, Zhuowei Li, Lisa A. Dailey, Yuh-Chin T. Huang. CEMALB, University of North Carolina, and ORD, US EPA, Chapel Hill, North Carolina.

    Exposure to particulate matter...

  19. Peer-Mediated Procedures to Induce Swallowing and Food Acceptance in Young Children.

    ERIC Educational Resources Information Center

    Greer, R. Douglas; And Others

    1991-01-01

    A peer modeling procedure was shown to induce swallowing in a young child with dysphagia, and to increase food acceptance in a young child who consistently declined food. A peer-mediated procedure, consisting of rotated opportunities to consume food with a peer, increased consumption more than did modeling alone. (Author/JDD)

  20. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation.

    PubMed

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  1. Nitric oxide-mediated bystander signal transduction induced by heavy-ion microbeam irradiation

    NASA Astrophysics Data System (ADS)

    Tomita, Masanori; Matsumoto, Hideki; Funayama, Tomoo; Yokota, Yuichiro; Otsuka, Kensuke; Maeda, Munetoshi; Kobayashi, Yasuhiko

    2015-07-01

    In general, a radiation-induced bystander response is known to be a cellular response induced in non-irradiated cells after receiving bystander signaling factors released from directly irradiated cells within a cell population. Bystander responses induced by high-linear energy transfer (LET) heavy ions at low fluence are an important health problem for astronauts in space. Bystander responses are mediated via physical cell-cell contact, such as gap-junction intercellular communication (GJIC) and/or diffusive factors released into the medium in cell culture conditions. Nitric oxide (NO) is a well-known major initiator/mediator of intercellular signaling within culture medium during bystander responses. In this study, we investigated the NO-mediated bystander signal transduction induced by high-LET argon (Ar)-ion microbeam irradiation of normal human fibroblasts. Foci formation by DNA double-strand break repair proteins was induced in non-irradiated cells, which were co-cultured with those irradiated by high-LET Ar-ion microbeams in the same culture plate. Foci formation was suppressed significantly by pretreatment with an NO scavenger. Furthermore, NO-mediated reproductive cell death was also induced in bystander cells. Phosphorylation of NF-κB and Akt were induced during NO-mediated bystander signaling in the irradiated and bystander cells. However, the activation of these proteins depended on the incubation time after irradiation. The accumulation of cyclooxygenase-2 (COX-2), a downstream target of NO and NF-κB, was observed in the bystander cells 6 h after irradiation but not in the directly irradiated cells. Our findings suggest that Akt- and NF-κB-dependent signaling pathways involving COX-2 play important roles in NO-mediated high-LET heavy-ion-induced bystander responses. In addition, COX-2 may be used as a molecular marker of high-LET heavy-ion-induced bystander cells to distinguish them from directly irradiated cells, although this may depend on the time

  2. Direct and indirect effects of maltreatment typologies on suicidality in a representative Northern Irish sample: Psychopathology only partially mediates the relationship.

    PubMed

    McKenna, Áine E; Gillen, Allison M C

    2016-01-01

    There has been a rise in suicide rates among men who grew up during the 1970's in Northern Ireland (NI). Conflict exposures (CEs) have been linked with suicide ideation but not attempts. Civil conflict has also been linked with aggressive parenting which is associated with the development of aggressive drives, psychopathology and suicidality. This study investigated (1) cohort specific associations between latent classes (LCs) of maltreatment and (2) associations between LCs, CEs, psychopathology and suicidality. Data were from NI Study of Health and Stress (N = 1986). Maltreatment and suicidality were queried using validated measures. Psychiatric assessments were based on DSM-IV criteria. Logistic regression, latent class analysis, chi square tests and mediation analyses were conducted. Two at risk LCs were identified, entitled "family violence exposure" (FVE, 10.4%; Male, 55.4%) and "family violence and sexual abuse exposure" (FVSAE, 1.2%; Female, 90.5%). Both were more likely to have experienced CEs (FVE = 71%; FVSAE = 77.5%) than the low risk class. The FVE were more likely to be male; aged 35-49 and to suffer from a mental disorder. The FVSAE class all endorsed rape, were more likely to be separated and to suffer from a mental disorder. CEs uniquely predicted ideation but not enactment. Psychopathology partially mediated the relationship between LCs and suicidality. FVE and FVSAE directly increased the odds of enactment. These findings are original and highly pertinent and they should be used to inform any strategy for addressing the cohort specific and trauma related rise in suicide rates in NI. PMID:26606724

  3. A bile‐inducible membrane protein mediates bifidobacterial bile resistance

    PubMed Central

    Ruiz, Lorena; O'Connell‐Motherway, Mary; Zomer, Aldert; de los Reyes‐Gavilán, Clara G.; Margolles, Abelardo; van Sinderen, Douwe

    2012-01-01

    Summary Bbr_0838 from Bifidobacterium breve UCC2003 is predicted to encode a 683 residue membrane protein, containing both a permease domain that displays similarity to transporters belonging to the major facilitator superfamily, as well as a CBS (cystathionine beta synthase) domain. The high level of similarity to bile efflux pumps from other bifidobacteria suggests a significant and general role for Bbr_0838 in bile tolerance. Bbr_0838 transcription was shown to be monocistronic and strongly induced upon exposure to bile. Further analysis delineated the transcriptional start site and the minimal region required for promoter activity and bile regulation. Insertional inactivation of Bbr_0838 in B. breve UCC2003 resulted in a strain, UCC2003:838800, which exhibited reduced survival upon cholate exposure as compared with the parent strain, a phenotype that was reversed when a functional, plasmid‐encoded Bbr_0838 gene was introduced into UCC2003:838800. Transcriptome analysis of UCC2003:838800 grown in the presence or absence of bile demonstrated that transcription of Bbr_0832, which is predicted to encode a macrolide efflux transporter gene, was significantly increased in the presence of bile, representing a likely compensatory mechanism for bile removal in the absence of Bbr_0838. This study represents the first in‐depth analysis of a bile‐inducible locus in bifidobacteria, identifying a key gene relevant for bifidobacterial bile tolerance. PMID:22296641

  4. Endothelial microparticles mediate inflammation-induced vascular calcification.

    PubMed

    Buendía, Paula; Montes de Oca, Addy; Madueño, Juan Antonio; Merino, Ana; Martín-Malo, Alejandro; Aljama, Pedro; Ramírez, Rafael; Rodríguez, Mariano; Carracedo, Julia

    2015-01-01

    Stimulation of endothelial cells (ECs) with TNF-α causes an increase in the expression of bone morphogenetic protein-2 (BMP-2) and the production of endothelial microparticles (EMPs). BMP-2 is known to produce osteogenic differentiation of vascular smooth muscle cells (VSMCs). It was found that EMPs from TNF-α-stimulated endothelial cells (HUVECs) contained a significant amount of BMP-2 and were able to enhance VSMC osteogenesis and calcification. Calcium content was greater in VSMCs exposed to EMPs from TNF-α-treated HUVECs than EMPs from nontreated HUVECs (3.56 ± 0.57 vs. 1.48 ± 0.56 µg/mg protein; P < 0.05). The increase in calcification was accompanied by up-regulation of Cbfa1 (osteogenic transcription factor) and down-regulation of SM22α (VSMC lineage marker). Inhibition of BMP-2 by small interfering RNA reduced the VSMC calcification induced by EMPs from TNF-α-treated HUVECs. Similar osteogenic capability was observed in EMPs from both patients with chronic kidney disease and senescent cells, which also presented a high level of BMP-2 expression. Labeling of EMPs with CellTracker shows that EMPs are phagocytized by VSMCs under all conditions (with or without high phosphate, control, and EMPs from TNF-α-treated HUVECs). Our data suggest that EC damage results in the release of EMPs with a high content of calcium and BMP-2 that are able to induce calcification and osteogenic differentiation of VSMCs. PMID:25342130

  5. Connexin32: a mediator of acetaminophen-induced liver injury?

    PubMed

    Maes, Michaël; McGill, Mitchell R; da Silva, Tereza Cristina; Lebofsky, Margitta; Maria Monteiro de Araújo, Cintia; Tiburcio, Taynã; Veloso Alves Pereira, Isabel; Willebrords, Joost; Crespo Yanguas, Sara; Farhood, Anwar; Zaidan Dagli, Maria Lucia; Jaeschke, Hartmut; Cogliati, Bruno; Vinken, Mathieu

    2016-02-01

    Connexin32 is the building block of hepatocellular gap junctions, which control direct intercellular communication and thereby act as goalkeepers of liver homeostasis. This study was set up to investigate whether connexin32 is involved in hepatotoxicity induced by the analgesic and antipyretic drug acetaminophen. To this end, whole body connexin32 knock-out mice were overdosed with acetaminophen followed by sampling at different time points within a 24-h time frame. Evaluation was done based upon a series of clinically and mechanistically relevant read-outs, including protein adduct formation, histopathological examination, measurement of alanine aminotransferase activity, cytokine production, levels of reduced and oxidized glutathione and hepatic protein amounts of proliferating cell nuclear antigen. In essence, it was found that genetic ablation of connexin32 has no influence on several key events in acetaminophen-induced hepatotoxicity, including cell death, inflammation or oxidative stress, yet it does affect production of protein adducts as well as proliferating cell nuclear antigen steady-state protein levels. This outcome is not in line with previous studies, which are contradicting on their own, as both amplification and alleviation of this toxicological process by connexin32 have been described. This could question the suitability of the currently available models and tools to investigate the role of connexin32 in acetaminophen-triggered hepatotoxicity. PMID:26739117

  6. Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii.

    PubMed

    Bhaduri, Swayamdipta; Debnath, Nandini; Mitra, Sushanta; Liu, Yang; Kumar, Aloke

    2016-01-01

    The particular bacterium under investigation here (S. pasteurii) is unique in its ability, under the right conditions, to induce the hydrolysis of urea (ureolysis) in naturally occurring environments through secretion of an enzyme urease. This process of ureolysis, through a chain of chemical reactions, leads to the formation of calcium carbonate precipitates. This is known as Microbiologically Induced Calcite Precipitation (MICP). The proper culture protocols for MICP are detailed here. Finally, visualization experiments under different modes of microscopy were performed to understand various aspects of the precipitation process. Techniques like optical microscopy, Scanning Electron Microscopy (SEM) and X-Ray Photo-electron Spectroscopy (XPS) were employed to chemically characterize the end-product. Further, the ability of these precipitates to clog pores inside a natural porous medium was demonstrated through a qualitative experiment where sponge bars were used to mimic a pore-network with a range of length scales. A sponge bar dipped in the culture medium containing the bacterial cells hardens due to the clogging of its pores resulting from the continuous process of chemical precipitation. This hardened sponge bar exhibits superior strength when compared to a control sponge bar which becomes compressed and squeezed under the action of an applied external load, while the hardened bar is able to support the same weight with little deformation. PMID:27167458

  7. Partitioning Direct and Indirect Human-induced Carbon Sequestration in Managed Conifer Forests in Central Europe Using Model Simulations and Forest Inventories.

    NASA Astrophysics Data System (ADS)

    Vetter, M.; Wirth, C.; Böttcher, H.; Churkina, G.; Schulze, E. D.; Schwalbe, G.

    2003-12-01

    Forest ecosystems have long been known to be an important sink in the global carbon budget. The factors responsible for the strength of the sinks and their permanence, however, are not so clear. To distinguish between direct and indirect impact on the carbon sequestration we have to work on spatial and temporal scales where humans have a major impact on the ecosystem. In this paper we contrast the effects of indirect human induced environmental changes and forest age on carbon sequestration as well as direct human induced effects on carbon accumulation such as forest management of coniferous forests in central Europe from the end of 19-th century until present. Ecosystem process model BIOME-BGC has been used to study these effects and results have been corroborated with forest inventories. We focused on conifer forests of Thuringia as a study case, because these forests are representative of central European forests and good forest inventories were available. Grouping the forests in three different strata differing in annual average temperatures and precipitation allowed us also to study the effect of elevation on carbon sequestration. Forests in all elevational strata showed an increase in vegetation carbon accumulation in all age classes as a result of environmental changes in the last 20 years (1982-2001). Young and old trees had the highest annual changes in the vegetation carbon during this period. Under pre-industrial conditions, trees older than 80 years showed almost no annual increase in vegetation C carbon accumulation. With industrial climate scenario those trees were still carbon sinks. Trees older than 100 years in the low elevations were an atmospheric carbon source in the pre-industrial case, but carbon sinks in the industrial case. Nitrogen-deposition had the highest impact on the net ecosystem production (NEP) for the high and middle elevations, whereas CO2 fertilization was most responsible for NEP changes in the low elevations. Under current

  8. Dexamethasone-induced apoptosis of osteocytic and osteoblastic cells is mediated by TAK1 activation.

    PubMed

    Ding, Heyuan; Wang, Tao; Xu, Dongli; Cha, Bingbing; Liu, Jun; Li, Yiming

    2015-05-01

    Increased apoptosis of osteoblasts and osteocytes is the main mechanism of glucocorticoid (GC)-induced osteonecrosis. In the current study, we investigated whether dexamethasone (Dex)-induced osteoblastic and osteocytic cell apoptosis is mediated through activation of transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1), and whether TAK1 inhibition could promote survival opposing the deleterious effects of Dex. We found that TAK1 was activated by Dex in both osteocytic MLO-Y4 and osteoblastic OB-6 cells, which was prevented by two known anti-oxidants N-acetylcysteine (NAC) and ebselen. TAK1 inhibitors, including LYTAK1 and 5Z-7-oxozeaenol (57-OZ), inhibited Dex-induced apoptosis of MLO-Y4 and OB-6 cells. Meanwhile shRNA-mediated knockdown of TAK1 also suppressed Dex-induced damages to MLO-Y4 and OB-6 cells. On the other hand, exogenously over-expressing TAK1 enhanced Dex-induced MLO-Y4 and OB-6 cell apoptosis. At the molecular level, we found that TAK1 mediated Dex-induced pro-apoptotic Pyk2-JNK activation. Inhibition or silencing of TAK1 almost abolished Pyk2-JNK phosphorylations by Dex in MLO-Y4 and OB-6 cells. TAK1 over-expression, on the other hand, increased Dex's activity on Pyk2-JNK phosphorylations in above cells. We conclude that part of the pro-apoptotic actions of Dex on osteoblastic and osteocytic cells are mediated through TAK1 activation, and that inhibition of TAK1 might protect from GC-induced damages to osteoblasts and osteocytes. PMID:25753204

  9. Role of oxidative stress in methamphetamine-induced dopaminergic toxicity mediated by protein kinase Cδ

    PubMed Central

    Nguyen, Xuan-Khanh Thi; Li, Zhengyi; Bing, Guoying; Bach, Jae-Hyung; Park, Dae Hun; Nakayama, Keiichi; Ali, Syed F.; Kanthasamy, Anumantha G.; Cadet, Jean Lud; Nabeshima, Toshitaka; Kim, Hyoung-Chun

    2014-01-01

    This study examined the role of protein kinase C (PKC) isozymes in methamphetamine (MA)-induced dopaminergic toxicity. Multiple-dose administration of MA did not significantly alter PKCα, PKCβI, PKCβII, or PKCζ expression in the striatum, but did significantly increase PKCδ expression. Gö6976 (a co-inhibitor of PKCα and -β), hispidin (PKCβ inhibitor), and PKCζ pseudosubstrate inhibitor (PKCζ inhibitor) did not significantly alter MA-induced behavioral impairments. However, rottlerin (PKCδ inhibitor) significantly attenuated behavioral impairments in a dose-dependent manner. In addition, MA-induced behavioral impairments were not apparent in PKCδ knockout (–/–) mice. MA-induced oxidative stress (i.e., lipid peroxidation and protein oxidation) was significantly attenuated in rottlerin-treated mice and was not apparent in PKCδ (–/–) mice. Consistent with this, MA-induced apoptosis (i.e., terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive apoptotic cells) was significantly attenuated in rottlerin-treated mice. Furthermore, MA-induced increases in the dopamine (DA) turnover rate and decreases in tyrosine hydroxylase (TH) activity and the expression of TH, dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT2) were not significantly observed in rottlerin-treated or PKCδ (–/–) mice. Our results suggest that PKCδ gene expression is a key mediator of oxidative stress and dopaminergic damage induced by MA. Thus, inhibition of PKCδ may be a useful target for protection against MA-induced neurotoxicity. PMID:22512859

  10. Angiotensin type 1 (AT1) and type 2 (AT2) receptors mediate the increase in TGF-beta1 in thyroid hormone-induced cardiac hypertrophy.

    PubMed

    Diniz, G P; Carneiro-Ramos, M S; Barreto-Chaves, M L M

    2007-04-01

    Increased thyroid hormone (TH) levels are known to induce cardiac hypertrophy. Some studies have provided evidence for a functional link between angiotensin II (ANG II) and transforming growth factor beta1 (TGF-beta1) in the heart, both being able to also induce cardiac hypertrophy. However, the contribution of this growth factor activated directly by TH or indirectly by ANG II in cardiac hypertrophy development remains unknown. To analyze the possible role of TGF-beta1 in cardiac hypertrophy induced by TH and also to evaluate if the TGF-beta1 effect is mediated by ANG II receptors, we employed Wistar rats separated into control, hypothyroid (hypo) and hyperthyroid (T4 - 10) groups combined or not with ANG II receptor blockers (losartan or PD123319). Serum levels of T3 and T4, systolic pressure and heart rate confirmed the thyroid state of the groups. The T4 - 10 group presented a significant increase in cardiac TGF-beta1 levels; however, TGF-beta1 levels in the hypo group did not change in relation to the control. Inhibition of the increase in cardiac TGF-beta1 levels was observed in the groups treated with T4 in association with losartan or PD123319 when compared to the T4 - 10 group. These results demonstrate for the first time the TH-modulated induction of cardiac TGF-beta1 in cardiac hypertrophy, and that this effect is mediated by ANG II receptors. PMID:17206447

  11. Central Mechanisms Mediating Thrombospondin-4-induced Pain States.

    PubMed

    Park, John; Yu, Yanhui Peter; Zhou, Chun-Yi; Li, Kang-Wu; Wang, Dongqing; Chang, Eric; Kim, Doo-Sik; Vo, Benjamin; Zhang, Xia; Gong, Nian; Sharp, Kelli; Steward, Oswald; Vitko, Iuliia; Perez-Reyes, Edward; Eroglu, Cagla; Barres, Ben; Zaucke, Frank; Feng, Guoping; Luo, Z David

    2016-06-17

    Peripheral nerve injury induces increased expression of thrombospondin-4 (TSP4) in spinal cord and dorsal root ganglia that contributes to neuropathic pain states through unknown mechanisms. Here, we test the hypothesis that TSP4 activates its receptor, the voltage-gated calcium channel Cavα2δ1 subunit (Cavα2δ1), on sensory afferent terminals in dorsal spinal cord to promote excitatory synaptogenesis and central sensitization that contribute to neuropathic pain states. We show that there is a direct molecular interaction between TSP4 and Cavα2δ1 in the spinal cord in vivo and that TSP4/Cavα2δ1-dependent processes lead to increased behavioral sensitivities to stimuli. In dorsal spinal cord, TSP4/Cavα2δ1-dependent processes lead to increased frequency of miniature and amplitude of evoked excitatory post-synaptic currents in second-order neurons as well as increased VGlut2- and PSD95-positive puncta, indicative of increased excitatory synapses. Blockade of TSP4/Cavα2δ1-dependent processes with Cavα2δ1 ligand gabapentin or genetic Cavα2δ1 knockdown blocks TSP4 induced nociception and its pathological correlates. Conversely, TSP4 antibodies or genetic ablation blocks nociception and changes in synaptic transmission in mice overexpressing Cavα2δ1 Importantly, TSP4/Cavα2δ1-dependent processes also lead to similar behavioral and pathological changes in a neuropathic pain model of peripheral nerve injury. Thus, a TSP4/Cavα2δ1-dependent pathway activated by TSP4 or peripheral nerve injury promotes exaggerated presynaptic excitatory input and evoked sensory neuron hyperexcitability and excitatory synaptogenesis, which together lead to central sensitization and pain state development. PMID:27129212

  12. Nicotinic acetylcholine receptors mediate donepezil-induced oligodendrocyte differentiation.

    PubMed

    Imamura, Osamu; Arai, Masaaki; Dateki, Minori; Ogata, Toru; Uchida, Ryuji; Tomoda, Hiroshi; Takishima, Kunio

    2015-12-01

    Oligodendrocytes are the myelin-forming cells of the central nervous system (CNS). Failure of myelin development and oligodendrocyte loss results in serious human disorders, including multiple sclerosis. Here, we show that donepezil, an acetlycholinesterase inhibitor developed for the treatment of Alzheimer's disease, can stimulate oligodendrocyte differentiation and maturation of neural stem cell-derived oligodendrocyte progenitor cells without affecting proliferation or cell viability. Transcripts for essential myelin-associated genes, such as PLP, MAG, MBP, CNPase, and MOG, in addition to transcription factors that regulate oligodendrocyte differentiation and myelination, were rapidly increased after treatment with donepezil. Furthermore, luciferase assays confirmed that both MAG and MBP promoters display increased activity upon donepezil-induced oligodendrocytes differentiation, suggesting that donepezil increases myelin gene expression mainly through enhanced transcription. We also found that the increase in the number of oligodendrocytes observed following donepezil treatment was significantly inhibited by the nicotinic acetylcholine receptor (nAChR) antagonist mecamylamine, but not by the muscarinic acetylcholine receptor antagonist scopolamine. Moreover, donepezil-induced myelin-related gene expression was suppressed by mecamylamine at both the mRNA and protein level. These results suggest that donepezil stimulates oligodendrocyte differentiation and myelin-related gene expression via nAChRs in neural stem cell-derived oligodendrocyte progenitor cells. We show that donepezil, a drug for the treatment of Alzheimer disease, can stimulate oligodendrocyte differentiation and maturation of oligodendrocyte progenitor cells. Transcripts for essential myelin-associated genes, such as PLP, MAG, MBP, CNPase and MOG in addition to transcripton factors that regulate oligodendrocyte differentiation and myelination were rapidly increased after treatment with donepezil

  13. Inducer-mediated commitment of murine erythroleukemia cells to differentiation: a multistep process.

    PubMed Central

    Chen, Z; Banks, J; Rifkind, R A; Marks, P A

    1982-01-01

    There are a number of agents which, when added to cultures of murine erythroleukemia cells (MELC), markedly increase the probability of commitment to express the characteristics of terminal erythroid differentiation, including loss of proliferative capacity and increased accumulation of globin mRNA and hemoglobin. Some characteristics of inducer-mediated commitment of MELC to terminal erythroid differentiation were examined by determining the effects of dexamethasone (an inhibitor of inducer-mediated MELC differentiation) and of hemin (an inducer of globin mRNA accumulation). Previously, it was shown that exposure of MELC to hexamethylene-bisacetamide (HMBA) leads to commitment, detectable within 12 hr. MELC cultured with both HMBA and dexamethasone do not express commitment. MELC transferred from culture with HMBA and dexamethasone to cloning medium without these agents express commitment to terminal erythroid differentiation, indicating that MELC retain a "memory" for some early HMBA-mediated changes leading to commitment which occur even in the presence of the inhibitory steroid. The kinetics of commitment in experiments in which exposure to HMBA is interrupted, or dexamethasone is added to the culture in HMBA, suggest that there is a rate-limiting step early in the commitment process. The memory for this step persists for more than one cell cycle. Addition of hemin to cultures with HMBA and dexamethasone initiated accumulation of globin mRNA but does not reverse the steroid-mediated inhibition of terminal cell division (that is, the cells retain their proliferative capacity). Inducer-mediated MELC commitment is associated with accumulation of the chromatin protein IP25; dexamethasone does not inhibit this accumulation. Accumulation of IP25 may be inducer-related, but it is not sufficient to cause expression of terminal erythroid differentiation. Images PMID:6952199

  14. Indirect bonding mechanism for proximity-induced giant spin-orbit coupling in graphene-topological insulator van der Waals heterostructure

    NASA Astrophysics Data System (ADS)

    Rajput, Shivani; Li, Yaoyi; Weinert, Michael; Li, Lian

    We demonstrate proximity-induced spin-orbit coupling in graphene/topological insulator van der Waals (vdW) heterostructures fabricated by transferring chemical vapor deposited graphene onto Bi2Se3 film grown by molecular beam epitaxy. Using scanning tunneling microscopy/spectroscopy, we observe a spin-orbit splitting of the graphene Dirac states up to 80 meV, with a spatial variation of +/-20 meV due to the inherent lack of epitaxial relation in the graphene/Bi2Se3 vdW junction. Density functional theory calculations further reveal that this giant spin-orbit splitting of the graphene bands is a consequence of the orthogonalization requirement on the overlapping wave functions, rather than simple direct bonding at the interface. This revelation of an indirect bonding mechanism of the proximity effect will facilitate more effective engineering of desired properties in vdW heterostructures. This work is supported by the U.S. Department of Energy under Award DE-FG02-07ER46228.

  15. Indirect autonomic nervous system activity assessment with heart rate variability in rats with cyclophosphamide-induced hemorrhagic cystitis treated with melatonin or agomelatine

    PubMed Central

    Baranowska, Agnieszka; Thor, Piotr J.

    2015-01-01

    Aim of the study Melatonin (MLT) is reported to exert uroprotective effect due to its antioxidant/anti-inflammatory properties. It is unknown whether that effect also results from melatonin receptor activation, or it is attributed to the modulation of the autonomic nervous system (ANS) activity. Our purpose was to evaluate the effect of MLT and agomelatine (AMT) – melatonin receptor agonist on ANS activity, indirectly assessed by heart rate variability (HRV), in rats with cyclophosphamide-induced hemorrhagic cystitis (CP-HC). Material and methods CP-HC was induced in all rats by four doses of cyclophosphamide given intraperitoneally (i.p.) at the dose of 75 mg/kg/dose. Rats were divided on three experimental groups and during induction of cystitis were treated i.p. with: (1) saline (control group); (2A/2B) MTL given at the dose of 40 or 100 mg/kg/dose; (3A/3B) AMT given at the dose of 40 or 100 mg/kg/dose. HRV recordings were performed in anesthetized rats at the eight day of the study. Results Both 2A and 2B animals were characterized by an increase in all non-normalized components in HRV spectrum. Furthermore, normalized LF (nLF) increase along with normalized HF (nHF) decrease were demonstrated in 2B rats. AMT treatment resulted only in an increase in total power (TP) and very low frequency (VLF) in 3A animals. Conclusions CP-HC rats treated with MLT were characterized by global ANS activity elevation, with a marked sympathetic tone predominance in subgroup 2B. Since the AMT treatment had no effect on autonomic function, it seems that melatonin modulates autonomic activity via non-receptor mechanisms. PMID:26793020

  16. Endoplasmic reticulum stress mediates withaferin A-induced apoptosis in human renal carcinoma cells.

    PubMed

    Choi, Min Jung; Park, Eun Jung; Min, Kyoung Jin; Park, Jong-Wook; Kwon, Taeg Kyu

    2011-04-01

    The accumulation of misfolded proteins in the lumen of the endoplasmic reticulum (ER) results in cellular stress that initiates a specialized response designated as the unfolded protein response. ER stress has been implicated in a variety of common diseases, such as diabetes, ischemia and neurodegenerative disorders. Withaferin A, a major chemical constituent of Withania somnifera, has been reported to inhibit tumor cell growth. We show that withaferin A induced a dose-dependent apoptotic cell death in several types of human cancer cells, as measured by FACS analysis and PARP cleavage. Treatment of Caki cells with withaferin A induced a number of signature ER stress markers, including phosphorylation of eukaryotic initiation factor-2α (eIF-2 α), ER stress-specific XBP1 splicing, and up-regulation of glucose-regulated protein (GRP)-78. In addition, withaferin A caused up-regulation of CAAT/enhancer-binding protein-homologous protein (CHOP), suggesting the induction of ER stress. Pretreatment with N-acetyl cysteine (NAC) significantly inhibited withaferin A-mediated ER stress proteins and cell death, suggesting that reactive oxygen species (ROS) mediate withaferin A-induced ER stress. Furthermore, CHOP siRNA or inhibition of caspase-4 activity attenuated withaferin A-induced apoptosis. Taken together, the present study provides strong evidence supporting an important role of the ER stress response in mediating withaferin A-induced apoptosis. PMID:21266191

  17. 27 CFR 6.26 - Indirect interest.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Indirect interest. 6.26 Section 6.26 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in...

  18. 27 CFR 6.32 - Indirect interest.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Indirect interest. 6.32 Section 6.32 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in...

  19. 27 CFR 6.26 - Indirect interest.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Indirect interest. 6.26 Section 6.26 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in...

  20. 27 CFR 6.26 - Indirect interest.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Indirect interest. 6.26 Section 6.26 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in...

  1. 27 CFR 6.26 - Indirect interest.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Indirect interest. 6.26 Section 6.26 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in...

  2. 27 CFR 6.32 - Indirect interest.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Indirect interest. 6.32 Section 6.32 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in...

  3. 27 CFR 6.32 - Indirect interest.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Indirect interest. 6.32 Section 6.32 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in...

  4. 27 CFR 6.32 - Indirect interest.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Indirect interest. 6.32 Section 6.32 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY ALCOHOL âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in...

  5. 27 CFR 6.26 - Indirect interest.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Indirect interest. 6.26... OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail License § 6.26 Indirect interest. Industry member interest in retail licenses includes any interest acquired by corporate...

  6. 27 CFR 6.32 - Indirect interest.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Indirect interest. 6.32... OF THE TREASURY LIQUORS âTIED-HOUSEâ Unlawful Inducements Interest in Retail Property § 6.32 Indirect interest. Industry member interest in retail property includes any interest acquired by corporate...

  7. Methylanthraquinone from Hedyotis diffusa WILLD induces Ca(2+)-mediated apoptosis in human breast cancer cells.

    PubMed

    Liu, Zheng; Liu, Ming; Liu, Miao; Li, Jianchun

    2010-02-01

    Methylanthraquinone from Hedyotis diffusa WILLD exhibited potent anticancer activity in many kinds of cancer cells. However, the exact mechanism and signaling pathway involved in methylanthraquinone-induced apoptosis have not been fully elucidated. Therefore, we explored the mechanisms of methylanthraquinone-mediated apoptosis in MCF-7 human breast cancer cells. When MCF-7 cells were co-incubated with methylanthraquinone, the percentage of apoptotic cell and S phase of cell cycle was markedly increased. In addition, a rise in intracellular calcium levels, phosphorylation of JNK and activation of calpain were found in MCF-7 cells after exposure to methylanthraquinone. With the methylanthraquinone-mediated reduction of mitochondrial membrane potential, cytochrome c was released from mitochondria to cytosol. Moreover, methylanthraquinone strongly induced cleavage of caspase-4, caspase-9 and caspase-7 in MCF-7 cells. These results suggested that methylanthraquinone from Hedyotis diffusa WILLD induced MCF-7 cells apoptosis via Ca(2+)/calpain/caspase-4 pathway. PMID:19686834

  8. Zinc-induced Neurotoxicity Mediated by Transient Receptor Potential Melastatin 7 Channels*

    PubMed Central

    Inoue, Koichi; Branigan, Deborah; Xiong, Zhi-Gang

    2010-01-01

    Transient receptor potential melastatin 7 (TRPM7) channels are novel Ca2+-permeable non-selective cation channels ubiquitously expressed. Activation of TRPM7 channels has been shown to be involved in cellular Mg2+ homeostasis, diseases caused by abnormal magnesium absorption, and in Ca2+-mediated neuronal injury under ischemic conditions. Here we show strong evidence suggesting that TRPM7 channels also play an important role in cellular Zn2+ homeostasis and in Zn2+-mediated neuronal injury. Using a combination of fluorescent Zn2+ imaging, small interfering RNA, pharmacological analysis, and cell injury assays, we show that activation of TRPM7 channels augmented Zn2+-induced injury of cultured mouse cortical neurons. The Zn2+-mediated neurotoxicity was inhibited by nonspecific TRPM7 blockers Gd3+ or 2-aminoethoxydiphenyl borate, and by knockdown of TRPM7 channels with small interfering RNA. In addition, Zn2+-mediated neuronal injury under oxygen-glucose deprivation conditions was also diminished by silencing TRPM7. Furthermore, we show that overexpression of TRPM7 channels in HEK293 cells increased intracellular Zn2+ accumulation and Zn2+-induced cell injury, while silencing TRPM7 by small interfering RNA attenuated the Zn2+-mediated cell toxicity. Thus, TRPM7 channels may represent a novel target for neurological disorders where Zn2+ toxicity plays an important role. PMID:20048154

  9. Zinc-induced neurotoxicity mediated by transient receptor potential melastatin 7 channels.

    PubMed

    Inoue, Koichi; Branigan, Deborah; Xiong, Zhi-Gang

    2010-03-01

    Transient receptor potential melastatin 7 (TRPM7) channels are novel Ca(2+)-permeable non-selective cation channels ubiquitously expressed. Activation of TRPM7 channels has been shown to be involved in cellular Mg(2+) homeostasis, diseases caused by abnormal magnesium absorption, and in Ca(2+)-mediated neuronal injury under ischemic conditions. Here we show strong evidence suggesting that TRPM7 channels also play an important role in cellular Zn(2+) homeostasis and in Zn(2+)-mediated neuronal injury. Using a combination of fluorescent Zn(2+) imaging, small interfering RNA, pharmacological analysis, and cell injury assays, we show that activation of TRPM7 channels augmented Zn(2+)-induced injury of cultured mouse cortical neurons. The Zn(2+)-mediated neurotoxicity was inhibited by nonspecific TRPM7 blockers Gd(3+) or 2-aminoethoxydiphenyl borate, and by knockdown of TRPM7 channels with small interfering RNA. In addition, Zn(2+)-mediated neuronal injury under oxygen-glucose deprivation conditions was also diminished by silencing TRPM7. Furthermore, we show that overexpression of TRPM7 channels in HEK293 cells increased intracellular Zn(2+) accumulation and Zn(2+)-induced cell injury, while silencing TRPM7 by small interfering RNA attenuated the Zn(2+)-mediated cell toxicity. Thus, TRPM7 channels may represent a novel target for neurological disorders where Zn(2+) toxicity plays an important role. PMID:20048154

  10. Oxidative Stress Mediates Radiation Lung Injury by Inducing Apoptosis

    SciTech Connect

    Zhang Yu; Zhang Xiuwu; Rabbani, Zahid N.; Jackson, Isabel L.; Vujaskovic, Zeljko

    2012-06-01

    Purpose: Apoptosis in irradiated normal lung tissue has been observed several weeks after radiation. However, the signaling pathway propagating cell death after radiation remains unknown. Methods and Materials: C57BL/6J mice were irradiated with 15 Gy to the whole thorax. Pro-apoptotic signaling was evaluated 6 weeks after radiation with or without administration of AEOL10150, a potent catalytic scavenger of reactive oxygen and nitrogen species. Results: Apoptosis was observed primarily in type I and type II pneumocytes and endothelium. Apoptosis correlated with increased PTEN expression, inhibition of downstream PI3K/AKT signaling, and increased p53 and Bax protein levels. Transforming growth factor-{beta}1, Nox4, and oxidative stress were also increased 6 weeks after radiation. Therapeutic administration of AEOL10150 suppressed pro-apoptotic signaling and dramatically reduced the number of apoptotic cells. Conclusion: Increased PTEN signaling after radiation results in apoptosis of lung parenchymal cells. We hypothesize that upregulation of PTEN is influenced by Nox4-derived oxidative stress. To our knowledge, this is the first study to highlight the role of PTEN in radiation-induced pulmonary toxicity.

  11. NO-induced relaxation of labouring and non-labouring human myometrium is not mediated by cyclic GMP.

    PubMed

    Buxton, I L; Kaiser, R A; Malmquist, N A; Tichenor, S

    2001-09-01

    1. In myometrial strips from near-term non-labouring human uterus, addition of oxytocin (OT) evoked dose-dependent (10 - 3000 nM) phasic contractions that were antagonized by atosiban (1 microM) and relaxed by addition of the nitric oxide donor S-nitroso L-cysteine (Cys-NO). In near-term labouring myometrium, however, addition of OT was ineffective at raising additional tone. 2. In both labouring and non-labouring tissue, Cys-NO mediated relaxation of spontaneous or OT-induced contractions (IC(50)=1 microM) was unaffected by prior addition of the guanylyl cyclase (GC) inhibitors ODQ (1H-[1,2,4]oxadiazolo[4,3,-alpha]quinoxalin-1-one; 1 microM), or methylene blue (MB; 10 microM). 3. Elevation of intracellular cyclic GMP accompanying 30 microM Cys-NO addition in non-labouring tissue (7.5 fold) or in labouring tissues (2.5 fold) was completely blocked in tissues that had been pre-treated with ODQ or MB. 4. Charybdotoxin (ChTx), iberiotoxin (IbTx) and kaliotoxin (KalTx) all shifted the Cys-NO inhibition curve to the right and reduced the degree of relaxation produced by maximal Cys-NO treatment (100 microM in non-labouring tissue; in labouring tissue, KalTx prevented Cys-NO mediated relaxation in both stimulated and unstimulated tissue. 5. Addition of the NO-donor S-nitroso N-acetyl penicillamine (SNAP) produced a dose-dependent relaxation of pregnant myometrium while 3-morpholinosyndonimine (SIN-1) did not. The failure of SIN-1 to relax OT-induced contractions was not due to a failure of the donor to stimulate myometrial GC. 6. We demonstrate that despite the ability of NO to stimulate myometrial GC in pregnant uterine muscle, relaxations are independent of cyclic GMP action. Effects of K(+)-channel inhibitors suggests that NO-induced relaxation in human uterine smooth muscle may be subserved by direct or indirect activation of one or more calcium-activated K(+)-channels. PMID:11522613

  12. Sulforaphane protects Microcystin-LR-induced toxicity through activation of the Nrf2-mediated defensive response

    SciTech Connect

    Gan Nanqin; Mi Lixin; Sun Xiaoyun; Dai Guofei; Chung Funglung; Song Lirong

    2010-09-01

    Microcystins (MCs), a cyclic heptapeptide hepatotoxins, are mainly produced by the bloom-forming cyanobacerium Microcystis, which has become an environmental hazard worldwide. Long term consumption of MC-contaminated water may induce liver damage, liver cancer, and even human death. Therefore, in addition to removal of MCs in drinking water, novel strategies that prevent health damages are urgently needed. Sulforaphane (SFN), a natural-occurring isothiocyanate from cruciferous vegetables, has been reported to reduce and eliminate toxicities from xenobiotics and carcinogens. The purpose of the present study was to provide mechanistic insights into the SFN-induced antioxidative defense system against MC-LR-induced cytotoxicity. We performed cell viability assays, including MTS assay, colony formation assay and apoptotic cell sorting, to study MC-LR-induced cellular damage and the protective effects by SFN. The results showed that SFN protected MC-LR-induced damages at a nontoxic and physiological relevant dose in HepG2, BRL-3A and NIH 3 T3 cells. The protection was Nrf2-mediated as evident by transactivation of Nrf2 and activation of its downstream genes, including NQO1 and HO-1, and elevated intracellular GSH level. Results of our studies indicate that pretreatment of cells with 10 {mu}M SFN for 12 h significantly protected cells from MC-LR-induced damage. SFN-induced protective response was mediated through Nrf2 pathway.

  13. Vibrio cholerae porin OmpU induces LPS tolerance by attenuating TLR-mediated signaling.

    PubMed

    Sakharwade, Sanica C; Mukhopadhaya, Arunika

    2015-12-01

    Porins can act as pathogen-associated molecular patterns, can be recognized by the host immune system and modulate immune responses. Vibrio choleraeporin OmpU aids in bacterial survival in the human gut by increasing resistance against bile acids and anti-microbial peptides. V. choleraeOmpU is pro-inflammatory in nature. However, interestingly, it can also down-regulate LPS-mediated pro-inflammatory responses. In this study, we have explored how OmpU-pretreatment affects LPS-mediated responses. Our study indicates that OmpU-pretreatment followed by LPS-activation does not induce M2-polarization of macrophages/monocytes. Further, OmpU attenuates LPS-mediated TLR2/TLR6 signaling by decreasing the association of TLRs along with recruitment of MyD88 and IRAKs to the receptor complex. This results in decreased translocation of NFκB in the nucleus. Additionally, OmpU-pretreatment up-regulates expression of IRAK-M, a negative regulator of TLR signaling, in RAW 264.7 mouse macrophage cells upon LPS-stimulation. Suppressor cytokine IL-10 is partially involved in OmpU-induced down-regulation of LPS-mediated TNFα production in human PBMCs. Furthermore, OmpU-pretreatment also affects macrophage function, by enhancing phagocytosis in LPS-treated RAW 264.7 cells, and down-regulates LPS-induced cell surface expression of co-stimulatory molecules. Altogether, OmpU causes suppression of LPS-mediated responses by attenuating the LPS-mediated TLR signaling pathway. PMID:26454478

  14. Anti-inflammatory mechanism of α-viniferin regulates lipopolysaccharide-induced release of proinflammatory mediators in BV2 microglial cells.

    PubMed

    Dilshara, Matharage Gayani; Lee, Kyoung-Tae; Kim, Hee Ju; Lee, Hak-Ju; Choi, Yung Hyun; Lee, Chang-Min; Kim, Lark Kyun; Kim, Gi-Young

    2014-07-01

    α-Viniferin is an oligostilbene of trimeric resveratrol and has anticancer activity; however, the molecular mechanism underlying the anti-inflammatory effects of α-viniferin has not been completely elucidated thus far. Therefore, we determined the mechanism by which α-viniferin regulates lipopolysaccharide (LPS)-induced expression of proinflammatory mediators in BV2 microglial cells. Treatment with α-viniferin isolated from Clematis mandshurica decreased LPS-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2). α-Viniferin also downregulated the LPS-induced expression of proinflammatory genes such as iNOS and COX-2 by suppressing the activity of nuclear factor kappa B (NF-κB) via dephosphorylation of Akt/PI3K. Treatment with a specific NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), indirectly showed that NF-κB is a crucial transcription factor for expression of these genes in the early stage of inflammation. Additionally, our results indicated that α-viniferin suppresses NO and PGE2 production in the late stage of inflammation through induction of heme oxygenase-1 (HO-1) regulated by nuclear factor erythroid 2-related factor (Nrf2). Taken together, our data indicate that α-viniferin suppresses the expression of proinflammatory genes iNOS and COX-2 in the early stage of inflammation by inhibiting the Akt/PI3K-dependent NF-κB activation and inhibits the production of proinflammatory mediators NO and PGE2 in the late stage by stimulating Nrf2-mediated HO-1 signaling pathway in LPS-stimulated BV2 microglial cells. These results suggest that α-viniferin may be a potential candidate to regulate LPS-induced inflammation. PMID:24859013

  15. Ring Substituents on Substituted Benzamide Ligands Indirectly Mediate Interactions with Position 7.39 of Transmembrane Helix 7 of the D4 Dopamine Receptor

    PubMed Central

    Ericksen, Spencer S.; Cummings, David F.; Teer, Michael E.; Amdani, Shahnawaz

    2012-01-01

    In an effort to delineate how specific molecular interactions of dopamine receptor ligand classes vary between D2-like dopamine receptor subtypes, a conserved threonine in transmembrane (TM) helix 7 (Thr7.39), implicated as a key ligand interaction site with biogenic amine G protein-coupled receptors, was substituted with alanine in D2 and D4 receptors. Interrogation of different ligand chemotypes for sensitivity to this substitution revealed enhanced affinity in the D4, but not the D2 receptor, specifically for substituted benzamides (SBAs) having polar 4- (para) and/or 5- (meta) benzamide ring substituents. D4-T7.39A was fully functional, and the mutation did not alter the sodium-mediated positive and negative allostery observed with SBAs and agonists, respectively. With the exception of the non-SBA ligand (+)-butaclamol, which, in contrast to certain SBAs, had decreased affinity for the D4-T7.39A mutant, the interactions of numerous other ligands were unaffected by this mutation. SBAs were docked into D4 models in the same mode as observed for eticlopride in the D3 crystal structure. In this mode, interactions with TM5 and TM6 residues constrain the SBA ring position that produces distal steric crowding between pyrrolidinyl/diethylamine moieties and D4-Thr7.39. Ligand-residue interaction energy profiles suggest this crowding is mitigated by substitution with a smaller alanine. The profiles indicate sites that contribute to the SBA binding interaction and site-specific energy changes imparted by the D4-T7.39A mutation. Substantial interaction energy changes are observed at only a few positions, some of which are not conserved among the dopamine receptor subtypes and thus seem to account for this D4 subtype-specific structure-activity relationship. PMID:22588261

  16. Two stage indirect evaporative cooling system

    DOEpatents

    Bourne, Richard C.; Lee, Brian E.; Callaway, Duncan

    2005-08-23

    A two stage indirect evaporative cooler that moves air from a blower mounted above the unit, vertically downward into dry air passages in an indirect stage and turns the air flow horizontally before leaving the indirect stage. After leaving the dry passages, a major air portion travels into the direct stage and the remainder of the air is induced by a pressure drop in the direct stage to turn 180.degree. and returns horizontally through wet passages in the indirect stage and out of the unit as exhaust air.

  17. Cell mediated immunity to corn starch in starch-induced granulomatous peritonitis.

    PubMed

    Goodacre, R L; Clancy, R L; Davidson, R A; Mullens, J E

    1976-03-01

    Two patients with histologically diagnosed starch induced granulomatous peritonitis (SGP) have been shown to have cell mediated immunity to corn starch using the techniques of macrophage migration inhibition and lymphocyte DNA synthesis. Control groups of normal subjects, patients with uncomplicated laparotomy, and patients with Crohn's disease were negative in both tests. Lymphocytes from two patients with band adhesions, one of whom had biopsy evidence of a granulomatous reaction to starch, were sensitized to starch. Cell mediated immunity to starch may contribute to the pathogenesis of SGP, and some band adhesions may be a chronic low grade manifestation of this disorder. PMID:1269987

  18. CHOP Contributes to, But Is Not the Only Mediator of, IAPP Induced β-Cell Apoptosis.

    PubMed

    Gurlo, T; Rivera, J F; Butler, A E; Cory, M; Hoang, J; Costes, S; Butler, Peter C

    2016-04-01

    The islet in type 2 diabetes is characterized by β-cell loss, increased β-cell apoptosis, and islet amyloid derived from islet amyloid polypeptide (IAPP). When protein misfolding protective mechanisms are overcome, human IAPP (h-IAPP) forms membrane permeant toxic oligomers that induce β-cell dysfunction and apoptosis. In humans with type 2 diabetes (T2D) and mice transgenic for h-IAPP, endoplasmic reticulum (ER) stress has been inferred from nuclear translocation of CCAAT/enhancer-binding protein homologous protein (CHOP), an established mediator of ER stress. To establish whether h-IAPP toxicity is mediated by ER stress, we evaluated diabetes onset and β-cell mass in h-IAPP transgenic (h-TG) mice with and without deletion of CHOP in comparison with wild-type controls. Diabetes was delayed in h-TG CHOP(-/-) mice, with relatively preserved β-cell mass and decreased β-cell apoptosis. Deletion of CHOP attenuates dysfunction of the autophagy/lysosomal pathway in β-cells of h-TG mice, uncovering a role for CHOP in mediating h-IAPP-induced dysfunction of autophagy. As deletion of CHOP delayed but did not prevent h-IAPP-induced β-cell loss and diabetes, we examined CHOP-independent stress pathways. JNK, a target of the IRE-1pTRAF2 complex, and the Bcl-2 family proapoptotic mediator BIM, a target of ATF4, were comparably activated by h-IAPP expression in the presence and absence of CHOP. Therefore, although these studies affirm that CHOP is a mediator of h-IAPP-induced ER stress, it is not the only one. Therefore, suppression of CHOP alone is unlikely to be a durable therapeutic strategy to protect against h-IAPP toxicity because multiple stress pathways are activated. PMID:26900721

  19. Polyphosphate induces matrix metalloproteinase-3-mediated proliferation of odontoblast-like cells derived from induced pluripotent stem cells

    SciTech Connect

    Ozeki, Nobuaki; Hase, Naoko; Yamaguchi, Hideyuki; Hiyama, Taiki; Kawai, Rie; Kondo, Ayami; Nakata, Kazuhiko; Mogi, Makio

    2015-05-01

    Inorganic polyphosphate [Poly(P)] may represent a physiological source of phosphate and has the ability to induce bone differentiation in osteoblasts. We previously reported that cytokine-induced matrix metalloproteinase (MMP)-3 accelerates the proliferation of purified odontoblast-like cells. In this study, MMP-3 small interfering RNA (siRNA) was transfected into odontoblast-like cells derived from induced pluripotent stem cells to investigate whether MMP-3 activity is induced by Poly(P) and/or is associated with cell proliferation and differentiation into odontoblast-like cells. Treatment with Poly(P) led to an increase in both cell proliferation and additional odontoblastic differentiation. Poly(P)-treated cells showed a small but significant increase in dentin sialophosphoprotein (DSPP) and dentin matrix protein-1 (DMP-1) mRNA expression, which are markers of mature odontoblasts. The cells also acquired additional odontoblast-specific properties including adoption of an odontoblastic phenotype typified by high alkaline phosphatase (ALP) activity and a calcification capacity. In addition, Poly(P) induced expression of MMP-3 mRNA and protein, and increased MMP-3 activity. MMP-3 siRNA-mediated disruption of the expression of these effectors potently suppressed the expression of odontoblastic biomarkers ALP, DSPP, and DMP-1, and blocked calcification. Interestingly, upon siRNA-mediated silencing of MMP-3, we noted a potent and significant decrease in cell proliferation. Using specific siRNAs, we revealed that a unique signaling cascade, Poly(P)→MMP-3→DSPP and/or DMP-1, was intimately involved in the proliferation of odontoblast-like cells. - Highlights: • Polyphosphate increases proliferation of iPS cell-derived odontoblast-like cells. • Polyphosphate-induced MMP-3 results in an increase of cell proliferation. • Induced cell proliferation involves MMP-3, DSPP, and/or DMP-1 sequentially. • Induced MMP-3 also results in an increase of odontoblastic

  20. Type I interferons induced by radiation therapy mediate recruitment and effector function of CD8(+) T cells.

    PubMed

    Lim, Joanne Y H; Gerber, Scott A; Murphy, Shawn P; Lord, Edith M

    2014-03-01

    The need for an intact immune system for cancer radiation therapy to be effective suggests that radiation not only acts directly on the tumor but also indirectly, through the activation of host immune components. Recent studies demonstrated that endogenous type I interferons (type I IFNs) play a role in radiation-mediated anti-tumor immunity by enhancing the ability of dendritic cells to cross-prime CD8(+) T cells. However, it is still unclear to what extent endogenous type I IFNs contribute to the recruitment and function of CD8(+) T cells. Little is also known about the effects of type I IFNs on myeloid cells. In the current study, we demonstrate that type I and type II IFNs (IFN-γ) are both required for the increased production of CXCL10 (IP-10) chemokine by myeloid cells within the tumor after radiation treatment. Radiation-induced intratumoral IP-10 levels in turn correlate with tumor-infiltrating CD8(+) T cell numbers. Moreover, type I IFNs promote potent tumor-reactive CD8(+) T cells by directly affecting the phenotype, effector molecule production, and enhancing cytolytic activity. Using a unique inducible expression system to increase local levels of IFN-α exogenously, we show here that the capacity of radiation therapy to result in tumor control can be enhanced. Our preclinical approach to study the effects of local increase in IFN-α levels can be used to further optimize the combination therapy strategy in terms of dosing and scheduling, which may lead to better clinical outcome. PMID:24357146

  1. Modeling Indirect Tunneling in Silicon

    NASA Astrophysics Data System (ADS)

    Chen, Edward

    Indirect tunneling in silicon p-n junctions catches people's attention again in recent years. First, the phenomenon induces a serious leakage problem, so called gate-induced drain leakage (GIDL) effect, in modern metal-oxide-semiconductor field-effect transistors (MOSFETs). Second, it is utilized to develop a novel tunneling transistor with the sharp turn-on ability for continuing ITRS roadmap. Although the indirect tunneling is important for the state-of-the-art transistor-technology, the accuracy of the present tunneling models in technology computer-aided design (TCAD) tools is still vague. In the research work, the theory of indirect tunneling in silicon has been thoroughly studied. The phonon-assisted tunneling model has been developed and compared with the existing ones in the Sentaurus-Synopsys, Medici-Synopsys, and Atlas-Silvaco TCAD tools. Beyond these existing models, ours successfully predicts the indirect tunneling current under the different field direction in silicon. In addition, bandgap narrowing in heavily-doped p-n junctions under the reverse-biased condition is also studied during the model development. At the end of the research work, the application to low standby power (LSTP) transistors is demonstrated to show the capability of our tunneling model in the device level.

  2. DNA methyltransferase I is a mediator of doxorubicin-induced genotoxicity in human cancer cells

    SciTech Connect

    Tan, Hwee Hong; Porter, Alan George

    2009-05-01

    Doxorubicin can induce the formation of extra-nuclear bodies during mitosis termed micronuclei but the underlying causes remain unknown. Here, we show that sub-lethal exposure to doxorubicin-induced micronuclei formation in human cancer cells but not in non-tumorigenic cells. Occurrence of micronuclei coincided with stability of DNMT1 upon doxorubicin assault, and DNMT1 was localized to the micronuclei structures. Furthermore, 5-aza-2'-deoxycytidine-mediated DNMT1 depletion or siDNMT1 knock-down attenuated the frequency of doxorubicin-induced micronucleated cells. Human DNMT1{sup -/-} cells displayed significantly fewer micronuclei compared to DNMT1{sup +/+} cells when challenged with doxorubicin, providing additional evidence for the involvement of DNMT1 in mediating such chromosomal aberrations. Collectively, our results demonstrate a role for DNMT1 in promoting DNA damage-induced genotoxicity in human cancer cells. DNMT1, recently identified as a candidate for doxorubicin-mediated cytotoxicity, is over-expressed in various cancer cell types. We propose that DNMT1 levels in tumor cells may determine the effectiveness of doxorubicin in chemotherapy.

  3. Nitric oxide: Mediator of nonadrenergic noncholinergic nerve-induced responses of opossum esophageal muscle

    SciTech Connect

    Murray, J.; Du, C.; Conklin, J.L.; Ledlow, A.; Bates, J.N. )

    1991-03-15

    Nonadrenergic noncholinergic (NANC) nerves of the opossum esophagus mediate relaxation of circular muscle from the lower esophageal sphincter (LES) and the off contraction of circular esophageal muscle. The latencies between the end of the stimulus and the off contraction describe a gradient such that the latency is longest in muscle from the caudad esophagus. N{sup G}-nitro-L-arginine (L-NNA), an inhibitor of nitric oxide synthase, and nitric oxide were used to test the hypothesis that NO is a mediator of these nerve-induced responses. Both electrical field stimulation (EFS) of intrinsic esophageal nerves and exogenous NO relaxed LES muscle. Only EFS-induced relaxation was inhibited by L-NNA. L-arginine, the substrate for NO synthase, antagonized the inhibitory effect of L-NNA. Exogenous NO neither relaxed nor contracted circular esophageal muscle. Both the amplitude and the latency of the off contraction were diminished by L-NNA. L-arginine antagonized the action of L-NNA. N{sup G}-nitro-L-arginine also attenuated the gradient in the latency of the off response by shortening latencies in muscle form the caudad esophagus. It had no effect on cholinergic nerve-induced contraction of longitudinal esophageal muscle. These data support the hypothesis that NO or an NO-containing compound mediates NANC nerve-induced responses of the esophagus and LES.

  4. Proteomic analysis of mismatch repair-mediated alkylating agent-induced DNA damage response

    PubMed Central

    2013-01-01

    Background Mediating DNA damage-induced apoptosis is an important genome-maintenance function of the mismatch repair (MMR) system. Defects in MMR not only cause carcinogenesis, but also render cancer cells highly resistant to chemotherapeutics, including alkylating agents. To understand the mechanisms of MMR-mediated apoptosis and MMR-deficiency-caused drug resistance, we analyze a model alkylating agent (N-methyl-N’-nitro-N-nitrosoguanidine, MNNG)-induced changes in protein phosphorylation and abundance in two cell lines, the MMR-proficient TK6 and its derivative MMR-deficient MT1. Results Under an experimental condition that MNNG-induced apoptosis was only observed in MutSα-proficient (TK6), but not in MutSα-deficient (MT1) cells, quantitative analysis of the proteomic data revealed differential expression and phosphorylation of numerous individual proteins and clusters of protein kinase substrates, as well differential activation of response pathways/networks in MNNG-treated TK6 and MT1 cells. Many alterations in TK6 cells are in favor of turning on the apoptotic machinery, while many of those in MT1 cells are to promote cell proliferation and anti-apoptosis. Conclusions Our work provides novel molecular insights into the mechanism of MMR-mediated DNA damage-induced apoptosis. PMID:24330662

  5. Desferrioxamine modulates chemically induced T helper 2-mediated autoimmunity in the rat

    PubMed Central

    WU, Z; HOLWILL, S D J; OLIVEIRA, D B G

    2004-01-01

    A rise in interleukin (IL) 4-dependent immunoglobulin E (IgE) is a hallmark of the mercuric chloride (HgCl2)-induced Th2-mediated autoimmune syndrome in the Brown Norway (BN) rat, and one of the mediators in allergic asthma in human. Oxidative stress, a potential factor related to the pathogenesis of allergy and asthma, has been shown to up-regulate IL-4 in mast cells and predispose to degranulation in vitro. However, it remains unknown whether oxidative/antioxidative imbalance plays a role in this Th2-driven model of autoimmunity in the rat. Here we show that administration of the non-sulphydryl-containing antioxidant desferrioxamine i.p. and s.c. to BN rats reduces HgCl2-enhanced IL-4 gene expression and inhibits HgCl2-induced Th2-mediated autoimmunity. Desferrioxamine treatment suppresses significantly IgE production and lymphoproliferation, and reduces tissue injury in the form of caecal vasculitis in the HgCl2-induced autoimmune syndrome. These results support a role for oxidative stress in the pathogenesis of the HgCl2-induced Th2-dominated autoimmune syndrome. This finding might have implications for understanding the mechanisms involved in Th2 cell responses as seen in allergy and asthma and thereby aid the development of new therapeutic strategies for these diseases. PMID:14738445

  6. Mechanisms mediating nitroglycerin-induced delayed-onset hyperalgesia in the rat.

    PubMed

    Ferrari, L F; Levine, J D; Green, P G

    2016-03-11

    Nitroglycerin (glycerol trinitrate, GTN) induces headache in migraineurs, an effect that has been used both diagnostically and in the study of the pathophysiology of this neurovascular pain syndrome. An important feature of this headache is a delay from the administration of GTN to headache onset that, because of GTN's very rapid metabolism, cannot be due to its pharmacokinetic profile. It has recently been suggested that activation of perivascular mast cells, which has been implicated in the pathophysiology of migraine, may contribute to this delay. We reported that hyperalgesia induced by intradermal GTN has a delay to onset of ∼ 30 min in male and ∼ 45 min in female rats. This hyperalgesia was greater in females, was prevented by pretreatment with the anti-migraine drug, sumatriptan, as well as by chronic pretreatment with the mast cell degranulator, compound 48/80. The acute administration of GTN and compound 48/80 both induced hyperalgesia that was prevented by pretreatment with octoxynol-9, which attenuates endothelial function, suggesting that GTN and mast cell-mediated hyperalgesia are endothelial cell-dependent. Furthermore, A-317491, a P2X3 antagonist, which inhibits endothelial cell-dependent hyperalgesia, also prevents GTN and mast cell-mediated hyperalgesia. We conclude that delayed-onset mechanical hyperalgesia induced by GTN is mediated by activation of mast cells, which in turn release mediators that stimulate endothelial cells to release ATP, to act on P2X3, a ligand-gated ion channel, in perivascular nociceptors. A role of the mast and endothelial cell in GTN-induced hyperalgesia suggests potential novel risk factors and targets for the treatment of migraine. PMID:26779834

  7. Mediation Analysis with Multiple Mediators

    PubMed Central

    VanderWeele, T.J.; Vansteelandt, S.

    2014-01-01

    Recent advances in the causal inference literature on mediation have extended traditional approaches to direct and indirect effects to settings that allow for interactions and non-linearities. In this paper, these approaches from causal inference are further extended to settings in which multiple mediators may be of interest. Two analytic approaches, one based on regression and one based on weighting are proposed to estimate the effect mediated through multiple mediators and the effects through other pathways. The approaches proposed here accommodate exposure-mediator interactions and, to a certain extent, mediator-mediator interactions as well. The methods handle binary or continuous mediators and binary, continuous or count outcomes. When the mediators affect one another, the strategy of trying to assess direct and indirect effects one mediator at a time will in general fail; the approach given in this paper can still be used. A characterization is moreover given as to when the sum of the mediated effects for multiple mediators considered separately will be equal to the mediated effect of all of the mediators considered jointly. The approach proposed in this paper is robust to unmeasured common causes of two or more mediators. PMID:25580377

  8. Activation of G proteins mediates flow-induced prostaglandin E2 production in osteoblasts

    NASA Technical Reports Server (NTRS)

    Reich, K. M.; McAllister, T. N.; Gudi, S.; Frangos, J. A.

    1997-01-01

    Interstitial fluid flow may play a role in load-induced bone remodeling. Previously, we have shown that fluid flow stimulates osteoblast production of cAMP inositol trisphosphate (IP3), and PGE2. Flow-induced increases in cAMP and IP3 were shown to be a result of PG production. Thus, PGE2 production appears to be an important component in fluid flow induced signal transduction. In the present study, we investigated the mechanism of flow-induced PGE2 synthesis. Flow-induced a 20-fold increase in PGE2 production in osteoblasts. Increases were also observed with ALF4-(10mM) (98-fold), an activator of guanidine nucleotide-binding proteins (G proteins), and calcium ionophore A23187 (2 microM) (100-fold) in stationary cells. We then investigated whether flow stimulation is mediated by G proteins and increases in intracellular calcium. Flow-induced PGE2 production was inhibited by the G protein inhibitors GDP beta S (100 microM) and pertussis toxin (1 microgram/ml) by 83% and 72%, respectively. Chelation of extracellular calcium by EGTA (2 mM) and intracellular calcium by quin-2/AM (30 microM) blocked flow stimulation by 87% and 67%, respectively. These results suggest that G proteins and calcium play an important role in mediating mechanochemical signal transduction in osteoblasts.

  9. Inducible and Reversible Lentiviral and Recombination Mediated Cassette Exchange (RMCE) Systems for Controlling Gene Expression

    PubMed Central

    Bersten, David C.; Sullivan, Adrienne E.; Li, Dian; Bhakti, Veronica; Bent, Stephen J.; Whitelaw, Murray L.

    2015-01-01

    Manipulation of gene expression to invoke loss of function (LoF) or gain of function (GoF) phenotypes is important for interrogating complex biological questions both in vitro and in vivo. Doxycycline (Dox)-inducible gene expression systems are commonly used although success is often limited by high background and insufficient sensitivity to Dox. Here we develop broadly applicable platforms for reliable, tightly controlled and reversible Dox-inducible systems for lentiviral mediated generation of cell lines or FLP Recombination-Mediated Cassette Exchange (RMCE) into the Collagen 1a1 (Col1a1) locus (FLP-In Col1a1) in mouse embryonic stem cells. We significantly improve the flexibility, usefulness and robustness of the Dox-inducible system by using Tetracycline (Tet) activator (Tet-On) variants which are more sensitive to Dox, have no background activity and are expressed from single Gateway-compatible constructs. We demonstrate the usefulness of these platforms in ectopic gene expression or gene knockdown in multiple cell lines, primary neurons and in FLP-In Col1a1 mouse embryonic stem cells. We also improve the flexibility of RMCE Dox-inducible systems by generating constructs that allow for tissue or cell type-specific Dox-inducible expression and generate a shRNA selection algorithm that can effectively predict potent shRNA sequences able to knockdown gene expression from single integrant constructs. These platforms provide flexible, reliable and broadly applicable inducible expression systems for studying gene function. PMID:25768837

  10. Complexity of lectin-mediated reactions in bacteria-induced histamine release.

    PubMed

    Jensen, C; Stahl Skov, P; Norn, S; Espersen, F; Bøg-Hansen, T C; Lihme, A

    1984-08-01

    We have earlier suggested that bacteria-induced histamine release is caused by different mechanisms, including allergic and non-immunological mechanisms, and that the latter probably depends on lectin-mediated reactions. Two possibilities of lectin-mediated reactions were examined in this study, bacterial surface lectins bind to sugars on the basophil cell membrane leading to histamine release, and the reverse reaction where bacterial aminosugars react with lectins on the basophil cell surface. In the bacterial histamine release caused by the Staph. aureus strain Wood 46 it was possible to demonstrate a reverse reaction, but not a bacterial lectin-mediated reaction. The reaction seems to be complex, as lower concentrations of sugars might potentiate the release of histamine by binding to the target cell or bacteria, while the release is inhibited by higher concentrations. PMID:6208803

  11. Tiam1 mediates neurite outgrowth induced by ephrin-B1 and EphA2

    PubMed Central

    Tanaka, Masamitsu; Ohashi, Riuko; Nakamura, Ritsuko; Shinmura, Kazuya; Kamo, Takaharu; Sakai, Ryuichi; Sugimura, Haruhiko

    2004-01-01

    Bidirectional signals mediated by Eph receptor tyrosine kinases and their membrane-bound ligands, ephrins, play pivotal roles in the formation of neural networks by induction of both collapse and elongation of neurites. However, the downstream molecular modules to deliver these cues are largely unknown. We report here that the interaction of a Rac1-specific guanine nucleotide-exchanging factor, Tiam1, with ephrin-B1 and EphA2 mediates neurite outgrowth. In cells coexpressing Tiam1 and ephrin-B1, Rac1 is activated by the extracellular stimulation of clustered soluble EphB2 receptors. Similarly, soluble ephrin-A1 activates Rac1 in cells coexpressing Tiam1 and EphA2. Cortical neurons from the E14 mouse embryos and neuroblastoma cells significantly extend neurites when placed on surfaces coated with the extracellular domain of EphB2 or ephrin-A1, which were abolished by the forced expression of the dominant-negative mutant of ephrin-B1 or EphA2. Furthermore, the introduction of a dominant-negative form of Tiam1 also inhibits neurite outgrowth induced by the ephrin-B1 and EphA2 signals. These results indicate that Tiam1 is required for neurite outgrowth induced by both ephrin-B1-mediated reverse signaling and EphA2-mediated forward signaling. PMID:14988728

  12. Astaxanthin Inhibits Expression of Retinal Oxidative Stress and Inflammatory Mediators in Streptozotocin-Induced Diabetic Rats

    PubMed Central

    Yeh, Po-Ting; Huang, Hsin-Wei; Yang, Chung-May; Yang, Wei-Shiung; Yang, Chang-Hao

    2016-01-01

    Purpose We evaluated whether orally administered astaxanthin (AST) protects against oxidative damage in the ocular tissues of streptozotocin (STZ)-induced diabetic rats. Methods and Results Fifty 6-week-old female Wistar rats were randomly assigned to receive an injection of STZ to induce diabetes (n = 40) or to remain uninduced (n = 10). The diabetic rats were randomly selected into four groups and they were separately administered normal saline, 0.6 mg/kg AST, 3 mg/kg AST, or 0.5 mg/kg lutein daily for eight weeks. Retinal functions of each group were evaluated by electroretinography. The expression of oxidative stress and inflammatory mediators in the ocular tissues was then assessed by immunohistochemistry, western blot analysis, ELISA, RT-PCR, and electrophoretic mobility shift assay (EMSA). Retinal functions were preserved by AST and lutein in different levels. Ocular tissues from AST- and lutein-treated rats had significantly reduced levels of oxidative stress mediators (8-hydroxy-2'-deoxyguanosine, nitrotyrosine, and acrolein) and inflammatory mediators (intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and fractalkine), increased levels of antioxidant enzymes (heme oxygenase-1 and peroxiredoxin), and reduced activity of the transcription factor nuclear factor-kappaB (NF-κB). Conclusion The xanthophyll carotenoids AST and lutein have neuroprotective effects and reduce ocular oxidative stress, and inflammation in the STZ diabetic rat model, which may be mediated by downregulation of NF-κB activity. PMID:26765843

  13. High avidity autoreactive CD4+ T cells induce host CTL, overcome Tregs and mediate tumor destruction

    PubMed Central

    Brandmaier, Andrew G.; Leitner, Wolfgang W.; Ha, Sung P.; Sidney, John; Restifo, Nicholas P.; Touloukian, Christopher E.

    2009-01-01

    Despite progress made over the past 25 years, existing immunotherapies have limited clinical effectiveness in patients with cancer. Immune tolerance consistently blunts the generated immune response, and the largely solitary focus on CD8+ T cell immunity has proven ineffective in the absence of CD4+ T cell help. To address these twin-tier deficiencies, we developed a translational model of melanoma immunotherapy focused on the exploitation of high avidity CD4+ T cells that become generated in germline antigen deficient mice. We had previously identified a TRP-1 specific HLA-DRB1*0401-restricted epitope. Using this epitope in conjunction with a newly described TRP-1 germline-knockout, we demonstrate that endogenous TRP-1 expression alters the functionality of the auto-reactive T cell repertoire. More importantly, we show, by using MHC-mismatched combinations, that CD4+ T cells derived from the self-antigen deficient host indirectly triggers the eradication of established B16 lung metastases. We demonstrate that the treatment effect is mediated entirely by endogenous CD8+ T cells and is not affected by the depletion of host Tregs. These findings suggest that high avidity CD4+ T cells can overcome endogenous conditions and mediate their anti-tumor effects exclusively through the elicitation of CD8+ T cell immunity. PMID:19561540

  14. TRPV4 channels mediate cyclic strain-induced endothelial cell reorientation through integrin to integrin signaling

    PubMed Central

    Thodeti, Charles K.; Matthews, Benjamin; Ravi, Arvind; Mammoto, Akiko; Ghosh, Kaustabh; Bracha, Abigail L.; Ingber, Donald E.

    2009-01-01

    Cyclic mechanical strain produced by pulsatile blood flow regulates the orientation of endothelial cells lining blood vessels, and influences critical processes such as angiogenesis. Mechanical stimulation of stretch-activated calcium channels is known to mediate this reorientation response, however, the molecular basis remains unknown. Here we show that cyclically stretching capillary endothelial cells adherent to flexible extracellular matrix substrates activates mechanosensitive TRPV4 ion channels that, in turn, stimulate phosphatidyl inositol-3-kinase-dependent activation and binding of additional ·1 integrin receptors, which promotes cytoskeletal remodeling and cell reorientation. Inhibition of integrin activation using blocking antibodies and knockdown of TRPV4 channels using specific siRNA suppress strain-induced capillary cell reorientation. Thus, mechanical forces that physically deform extracellular matrix may guide capillary cell reorientation through a strain-dependent ‘integrin to integrin’ signaling mechanism mediated by force-induced activation of mechanically-gated TRPV4 ion channels on the cell surface. PMID:19359599

  15. Indirection and computer security.

    SciTech Connect

    Berg, Michael J.

    2011-09-01

    The discipline of computer science is built on indirection. David Wheeler famously said, 'All problems in computer science can be solved by another layer of indirection. But that usually will create another problem'. We propose that every computer security vulnerability is yet another problem created by the indirections in system designs and that focusing on the indirections involved is a better way to design, evaluate, and compare security solutions. We are not proposing that indirection be avoided when solving problems, but that understanding the relationships between indirections and vulnerabilities is key to securing computer systems. Using this perspective, we analyze common vulnerabilities that plague our computer systems, consider the effectiveness of currently available security solutions, and propose several new security solutions.

  16. Lactacystin requires reactive oxygen species and Bax redistribution to induce mitochondria-mediated cell death

    PubMed Central

    Perez-Alvarez, Sergio; Solesio, Maria E; Manzanares, Jorge; Jordán, Joaquín; Galindo, María F

    2009-01-01

    Background and purpose: The proteasome inhibitor model of Parkinson's disease (PD) appears to reproduce many of the important behavioural, imaging, pathological and biochemical features of the human disease. However, the mechanisms involved in the lactacystin-induced, mitochondria-mediated apoptotic pathway remain poorly defined. Experimental approach: We have used lactacystin as a specific inhibitor of the 20S proteasome in the dopaminergic neuroblastoma cell line SH-SY5Y. We over-expressed a green fluorescent protein (GFP)–Bax fusion protein in these cells to study localization of Bax. Free radical scavengers were used to assess the role of reactive oxygen species (ROS) in these pathways. Key results: Lactacystin triggered a concentration-dependent increase in cell death mediated by the mitochondrial apoptotic pathway, and induced a change in mitochondrial membrane permeability accompanied by cytochrome c release. The participation of Bax protein was more critical than the formation of the permeability transition pore in mitochondria. GFP–Bax over-expression demonstrated Bax redistribution from the cytosol to mitochondria after the addition of lactacystin. ROS, but not p38 mitogen-activated protein kinase, participated in lactacystin-induced mitochondrial Bax translocation. Lactacystin disrupted the intracellular redox state by increasing ROS production and depleting endogenous antioxidant systems such as glutathione (GSH). Pharmacological depletion of GSH, using l-buthionine sulphoxide, potentiated lactacystin-induced cell death. Lactacystin sensitized neuroblastoma cells to oxidative damage, induced by subtoxic concentrations of 6-hydroxydopamine. Conclusions and implications: The lactacystin-induced, mitochondrial-mediated apoptotic pathway involved interactions between ROS, GSH and Bax. Lactacystin could constitute a potential factor in the development of sporadic PD. PMID:19785649

  17. Surface Grafting via Photo-Induced Copper-Mediated Radical Polymerization at Extremely Low Catalyst Concentrations.

    PubMed

    Laun, Joachim; Vorobii, Mariia; de los Santos Pereira, Andres; Pop-Georgievski, Ognen; Trouillet, Vanessa; Welle, Alexander; Barner-Kowollik, Christopher; Rodriguez-Emmenegger, Cesar; Junkers, Thomas

    2015-09-01

    Surface-initiated photo-induced copper-mediated radical polymerization is employed to graft a wide range of polyacrylate brushes from silicon substrates at extremely low catalyst concentrations. This is the first time that the controlled nature of the reported process is demonstrated via block copolymer formation and re-initiation experiments. In addition to unmatched copper catalyst concentrations in the range of few ppb, film thicknesses up to almost 1 μm are achieved within only 1 h. PMID:26149622

  18. Toll-like receptor 9 mediates CpG oligonucleotide-induced cellular invasion.

    PubMed

    Ilvesaro, Joanna M; Merrell, Melinda A; Li, Li; Wakchoure, Savita; Graves, David; Brooks, Sonja; Rahko, Eeva; Jukkola-Vuorinen, Arja; Vuopala, Katri S; Harris, Kevin W; Selander, Katri S

    2008-10-01

    Toll-like receptor 9 (TLR9) belongs to the innate immune system and recognizes microbial and vertebrate DNA. We showed previously that treatment with the TLR9-agonistic ODN M362 (a CpG sequence containing oligonucleotide) induces matrix metalloproteinase-13-mediated invasion in TLR9-expressing human cancer cell lines. Here, we further characterized the role of the TLR9 pathway in this process. We show that CpG oligonucleotides induce invasion in macrophages from wild-type C57/B6 and MyD88 knockout mice and in human MDA-MB-231 breast cancer cells lacking MyD88 expression. This effect was significantly inhibited in macrophages from TLR9 knockout mice and in human MDA-MB-231 breast cancer cells stably expressing TLR9 small interfering RNA or dominant-negative tumor necrosis factor receptor-associated factor 6 (TRAF6). Sequence modifications to the CpG oligonucleotides that targeted the stem loop and other secondary structures were shown to influence the invasion-inducing effect in MDA-MB-231 cells. In contrast, methylation of the cytosine residues of the parent CpG oligonucleotide did not affect the TLR9-mediated invasion compared with the unmethylated parent CpG oligonucleotide. Finally, expression of TLR9 was studied in clinical breast cancer samples and normal breast epithelium with immunohistochemistry. TLR9 staining localized in epithelial cells in both cancer and normal samples. The mean TLR9 staining intensity was significantly increased in the breast cancer cells compared with normal breast epithelial cells. In conclusion, our results suggest that TLR9 expression is increased in breast cancer and CpG oligonucleotide-induced cellular invasion is mediated via TLR9 and TRAF6, independent of MyD88. Further, our findings suggest that the structure and/or stability of DNA may influence the induction of TLR9-mediated invasion in breast cancer. PMID:18922969

  19. A plant vacuolar protease, VPE, mediates virus-induced hypersensitive cell death.

    PubMed

    Hatsugai, Noriyuki; Kuroyanagi, Miwa; Yamada, Kenji; Meshi, Tetsuo; Tsuda, Shinya; Kondo, Maki; Nishimura, Mikio; Hara-Nishimura, Ikuko

    2004-08-01

    Programmed cell death (PCD) in animals depends on caspase protease activity. Plants also exhibit PCD, for example as a response to pathogens, although a plant caspase remains elusive. Here we show that vacuolar processing enzyme (VPE) is a protease essential for a virus-induced hypersensitive response that involves PCD. VPE deficiency prevented virus-induced hypersensitive cell death in tobacco plants. VPE is structurally unrelated to caspases, although VPE has a caspase-1 activity. Thus, plants have evolved a regulated cellular suicide strategy that, unlike PCD of animals, is mediated by VPE and the cellular vacuole. PMID:15297671

  20. Bim mediates mitochondria-regulated particulate matter-induced apoptosis in alveolar epithelial cells

    PubMed Central

    Zhang, J.; Ghio, A.J.; Chang, W.; Kamdar, O.; Rosen, G.D.; Upadhyay, D.

    2007-01-01

    We studied the role of Bim, a pro-apoptotic BCL-2 family member in Airborne particulate matter (PM 2.5 μm)-induced apoptosis in alveolar epithelial cells (AEC). PM induced AEC apoptosis by causing significant reduction of mitochondrial membrane potential and increase in caspase-9, caspase-3 and PARP-1 activation. PM upregulated pro-apoptotic protein Bim and enhanced translocation of Bim to the mitochondria. ShRNABim blocked PM-induced apoptosis by preventing activation of the mitochondrial death pathway suggesting a role of Bim in the regulation of mitochondrial pathway in AEC. Accordingly, we provide the evidence that Bim mediates PM-induced apoptosis via mitochondrial pathway. PMID:17716672

  1. FAAH-mediated modulation of TLR3-induced neuroinflammation in the rat hippocampus.

    PubMed

    Henry, Rebecca J; Kerr, Daniel M; Finn, David P; Roche, Michelle

    2014-11-15

    The present study examined the effect of enhancing fatty acid amide hydrolase (FAAH) substrate levels in vivo on Toll-like receptor (TLR)3-induced neuroinflammation. Systemic and central (i.c.v.) administration of the FAAH inhibitor URB597 increased hippocampal levels of the N-acylethanolamines palmitoylethanolamide and oleoylethanolamide, but not anandamide. Systemic URB597 increased IFNα, IFNγ and IL-6 expression following TLR3 activation and attenuated TLR3-induced IL-1β and TNFα expression. In comparison, central URB597 administration attenuated the TLR3-induced increase in TNFα and IFNγ expression (and associated downstream genes IP-10 and SOCS1), while concurrently increasing IL-10 expression. These data support an important role for FAAH-mediated regulation of TLR3-induced neuroinflammatory responses. PMID:25245162

  2. GPR109A (PUMA-G/HM74A) mediates nicotinic acid-induced flushing.

    PubMed

    Benyó, Zoltán; Gille, Andreas; Kero, Jukka; Csiky, Marion; Suchánková, Marie Catherine; Nüsing, Rolf M; Moers, Alexandra; Pfeffer, Klaus; Offermanns, Stefan

    2005-12-01

    Nicotinic acid (niacin) has long been used as an antidyslipidemic drug. Its special profile of actions, especially the rise in HDL-cholesterol levels induced by nicotinic acid, is unique among the currently available pharmacological tools to treat lipid disorders. Recently, a G-protein-coupled receptor, termed GPR109A (HM74A in humans, PUMA-G in mice), was described and shown to mediate the nicotinic acid-induced antilipolytic effects in adipocytes. One of the major problems of the pharmacotherapeutical use of nicotinic acid is a strong flushing response. This side effect, although harmless, strongly affects patient compliance. In the present study, we show that mice lacking PUMA-G did not show nicotinic acid-induced flushing. In addition, flushing in response to nicotinic acid was also abrogated in the absence of cyclooxygenase type 1, and mice lacking prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) receptors had reduced flushing responses. The mouse orthologue of GPR109A, PUMA-G, is highly expressed in macrophages and other immune cells, and transplantation of wild-type bone marrow into irradiated PUMA-G-deficient mice restored the nicotinic acid-induced flushing response. Our data clearly indicate that GPR109A mediates nicotinic acid-induced flushing and that this effect involves release of PGE(2) and PGD(2), most likely from immune cells of the skin. PMID:16322797

  3. Inflammatory cytokine-mediated evasion of virus-induced tumors from NK cell control

    PubMed Central

    Mishra, Rabinarayan; Polic, Bojan; Welsh, Raymond M.; Szomolanyi-Tsuda, Eva

    2013-01-01

    Infections with DNA tumor viruses, including members of the polyomavirus family, often result in tumor formation in immune-deficient hosts. The complex control involved in antiviral and antitumor immune responses during these infections can be studied in murine polyomavirus (PyV)-infected mice as a model. We found that NK cells efficiently kill cells derived from PyV-induced salivary gland tumors in vitro in an NKG2D (effector cell) -RAE-1 (target cell) - dependent manner, but in T cell-deficient mice NK cells only delay but do not prevent the development of PyV-induced tumors. Here we show that the PyV-induced tumors have infiltrating functional NK cells. The freshly removed tumors, however, lack surface RAE-1 expression, and the tumor tissues produce soluble factors that down-regulate RAE-1. These factors include the pro-inflammatory cytokines IL-1α, IL-1β, IL-33, and TNF. Each of these cytokines down-regulate RAE-1 expression and susceptibility to NK cell mediated cytotoxicity. CD11b+F4/80+ macrophages infiltrating the PyV-induced tumors produce high amounts of IL-1β and TNF. Thus, our data suggest a new mechanism whereby inflammatory cytokines generated in the tumor environment lead to evasion of NK cell-mediated control of virus-induced tumors. PMID:23772039

  4. Guard cell hydrogen peroxide and nitric oxide mediate elevated CO2 -induced stomatal movement in tomato.

    PubMed

    Shi, Kai; Li, Xin; Zhang, Huan; Zhang, Guanqun; Liu, Yaru; Zhou, Yanhong; Xia, Xiaojian; Chen, Zhixiang; Yu, Jingquan

    2015-10-01

    Climate change as a consequence of increasing atmospheric CO2 influences plant photosynthesis and transpiration. Although the involvement of stomata in plant responses to elevated CO2 has been well established, the underlying mechanism of elevated CO2 -induced stomatal movement remains largely unknown. We used diverse techniques, including laser scanning confocal microscopy, transmission electron microscopy, biochemical methodologies and gene silencing to investigate the signaling pathway for elevated CO2 -induced stomatal movement in tomato (Solanum lycopersicum). Elevated CO2 -induced stomatal closure was dependent on the production of RESPIRATORY BURST OXIDASE 1 (RBOH1)-mediated hydrogen peroxide (H2 O2 ) and NITRATE REDUCTASE (NR)-mediated nitric oxide (NO) in guard cells in an abscisic acid (ABA)-independent manner. Silencing of OPEN STOMATA 1 (OST1) compromised the elevated CO2 -induced accumulation of H2 O2 and NO, upregulation of SLOW ANION CHANNEL ASSOCIATED 1 (SLAC1) gene expression and reduction of stomatal aperture, whereas silencing of RBOH1 or NR had no effects on the expression of OST1. Our results demonstrate that as critical signaling molecules, RBOH1-dependent H2 O2 and NR-dependent NO act downstream of OST1 that regulate SLAC1 expression and elevated CO2 -induced stomatal movement. This information is crucial to deepen the understanding of CO2 signaling pathway in guard cells. PMID:26308648

  5. GPR109A (PUMA-G/HM74A) mediates nicotinic acid–induced flushing

    PubMed Central

    Benyó, Zoltán; Gille, Andreas; Kero, Jukka; Csiky, Marion; Suchánková, Marie Catherine; Nüsing, Rolf M.; Moers, Alexandra; Pfeffer, Klaus; Offermanns, Stefan

    2005-01-01

    Nicotinic acid (niacin) has long been used as an antidyslipidemic drug. Its special profile of actions, especially the rise in HDL-cholesterol levels induced by nicotinic acid, is unique among the currently available pharmacological tools to treat lipid disorders. Recently, a G-protein–coupled receptor, termed GPR109A (HM74A in humans, PUMA-G in mice), was described and shown to mediate the nicotinic acid–induced antilipolytic effects in adipocytes. One of the major problems of the pharmacotherapeutical use of nicotinic acid is a strong flushing response. This side effect, although harmless, strongly affects patient compliance. In the present study, we show that mice lacking PUMA-G did not show nicotinic acid–induced flushing. In addition, flushing in response to nicotinic acid was also abrogated in the absence of cyclooxygenase type 1, and mice lacking prostaglandin D2 (PGD2) and prostaglandin E2 (PGE2) receptors had reduced flushing responses. The mouse orthologue of GPR109A, PUMA-G, is highly expressed in macrophages and other immune cells, and transplantation of wild-type bone marrow into irradiated PUMA-G–deficient mice restored the nicotinic acid–induced flushing response. Our data clearly indicate that GPR109A mediates nicotinic acid–induced flushing and that this effect involves release of PGE2 and PGD2, most likely from immune cells of the skin. PMID:16322797

  6. Hindbrain GLP-1 receptor mediation of cisplatin-induced anorexia and nausea.

    PubMed

    De Jonghe, Bart C; Holland, Ruby A; Olivos, Diana R; Rupprecht, Laura E; Kanoski, Scott E; Hayes, Matthew R

    2016-01-01

    While chemotherapy-induced nausea and vomiting are clinically controlled in the acute (<24 h) phase following treatment, the anorexia, nausea, fatigue, and other illness-type behaviors during the delayed phase (>24 h) of chemotherapy are largely uncontrolled. As the hindbrain glucagon-like peptide-1 (GLP-1) system contributes to energy balance and mediates aversive and stressful stimuli, here we examine the hypothesis that hindbrain GLP-1 signaling mediates aspects of chemotherapy-induced nausea and reductions in feeding behavior in rats. Specifically, hindbrain GLP-1 receptor (GLP-1R) blockade, via 4th intracerebroventricular (ICV) exendin-(9-39) injections, attenuates the anorexia, body weight reduction, and pica (nausea-induced ingestion of kaolin clay) elicited by cisplatin chemotherapy during the delayed phase (48 h) of chemotherapy-induced nausea. Additionally, the present data provide evidence that the central GLP-1-producing preproglucagon neurons in the nucleus tractus solitarius (NTS) of the caudal brainstem are activated by cisplatin during the delayed phase of chemotherapy-induced nausea, as cisplatin led to a significant increase in c-Fos immunoreactivity in NTS GLP-1-immunoreactive neurons. These data support a growing body of literature suggesting that the central GLP-1 system may be a potential pharmaceutical target for adjunct anti-emetics used to treat the delayed-phase of nausea and emesis, anorexia, and body weight loss that accompany chemotherapy treatments. PMID:26522737

  7. Xanthine Oxidase Mediates Hypoxia-Inducible Factor-2α Degradation by Intermittent Hypoxia

    PubMed Central

    Nanduri, Jayasri; Vaddi, Damodara Reddy; Khan, Shakil A.; Wang, Ning; Makerenko, Vladislav; Prabhakar, Nanduri R.

    2013-01-01

    Sleep-disordered breathing with recurrent apnea produces chronic intermittent hypoxia (IH). We previously reported that IH leads to down-regulation of HIF-2α protein via a calpain-dependent signaling pathway resulting in oxidative stress. In the present study, we delineated the signaling pathways associated with calpain-dependent HIF-2α degradation in cell cultures and rats subjected to chronic IH. Reactive oxygen species (ROS) scavengers prevented HIF-2α degradation by IH and ROS mimetic decreased HIF-2α protein levels in rat pheochromocytoma PC12 cell cultures, suggesting that ROS mediate IH-induced HIF-2α degradation. IH activated xanthine oxidase (XO) by increased proteolytic conversion of xanthine dehydrogenase to XO. ROS generated by XO activated calpains, which contributed to HIF-2α degradation by IH. Calpain-induced HIF-2α degradation involves C-terminus but not the N-terminus of the HIF-2α protein. Pharmacological blockade as well as genetic knock down of XO prevented IH induced calpain activation and HIF-2α degradation in PC12 cells. Systemic administration of allopurinol to rats prevented IH-induced hypertension, oxidative stress and XO activation in adrenal medulla. These results demonstrate that ROS generated by XO activation mediates IH-induced HIF-2α degradation via activation of calpains. PMID:24124516

  8. Inhibition of Propionibacterium acnes-induced mediators of inflammation by Indian herbs.

    PubMed

    Jain, A; Basal, E

    2003-01-01

    Propionibacterium acnes, an anaerobic pathogen, plays an important role in the pathogenesis of acne by inducing certain inflammatory mediators. These mediators include reactive oxygen species (ROS) and pro-inflammatory cytokines. In the present study, ROS, interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) were used as the major criteria for the evaluation of anti-inflammatory activity. To prove the anti-inflammatory effects of herbs, polymorphonuclear leukocytes (PMNL) and monocytes were treated with culture supernatant of P. acnes in the presence or absence of herbs. It was found that Rubia cordifolia, Curcuma longa, Hemidesmus indicus, and Azadirachta indica caused a statistically significant suppression of ROS from PMNL. Sphaeranthus indicus caused a smaller, still significant suppression of ROS. Aloe vera had no effect on ROS production. In the case of proinflammatory cytokine-induced monocytes, maximum suppression was shown by Azadirachta indica and Sphaeranthus indicus, followed by Hemidesmus indicus, Rubia cordifolia, and Curcuma longa. Aloe vera showed insignificant inhibitory activity. Thus, these herbs shows anti-inflammatory activity by suppressing the capacity of P. acnes-induced ROS and pro-inflammatory cytokines, the two important inflammatory mediators in acne pathogenesis. PMID:12622461

  9. Vitamin K2 covalently binds to Bak and induces Bak-mediated apoptosis.

    PubMed

    Karasawa, Satoki; Azuma, Motoki; Kasama, Takeshi; Sakamoto, Satoshi; Kabe, Yasuaki; Imai, Takeshi; Yamaguchi, Yuki; Miyazawa, Keisuke; Handa, Hiroshi

    2013-03-01

    Vitamin K2 (VK2, menaquinone) is known to have anticancer activity in vitro and in vivo. Although its effect is thought to be mediated, at least in part, by the induction of apoptosis, the underlying molecular mechanism remains elusive. Here, we identified Bcl-2 antagonist killer 1 (Bak) as a molecular target of VK2-induced apoptosis. VK2 directly interacts with Bak and induces mitochondrial-mediated apoptosis. Although Bak and Bcl-2-associated X protein (Bax), another member of the Bcl-2 family, are generally thought to be functionally redundant, only Bak is necessary and sufficient for VK2-induced cytochrome c (cyt c) release and cell death. Moreover, VK2-2,3 epoxide, an intracellular metabolite of VK2, was shown to covalently bind to the cysteine-166 residue of Bak. Several lines of evidence suggested that the covalent attachment of VK2 is critical for apoptosis induction. Thus this study reveals a specific role for Bak in mitochondria-mediated apoptosis. This study also provides insight into the anticancer effects of VK2 and suggests that Bak may be a potential target of cancer therapy. PMID:23229512

  10. IL-33 mediates antigen-induced cutaneous and articular hypernociception in mice

    PubMed Central

    Verri, Waldiceu A.; Guerrero, Ana T. G.; Fukada, Sandra Y.; Valerio, Daniel A.; Cunha, Thiago M.; Xu, Damo; Ferreira, Sérgio H.; Liew, Foo Y.; Cunha, Fernando Q.

    2008-01-01

    IL-33, a new member of the IL-1 family, signals through its receptor ST2 and induces T helper 2 (Th2) cytokine synthesis and mediates inflammatory response. We have investigated the role of IL-33 in antigen-induced hypernociception. Recombinant IL-33 induced cutaneous and articular mechanical hypernociception in a time- and dose-dependent manner. The hypernociception was inhibited by soluble (s) ST2 (a decoy receptor of IL-33), IL-1 receptor antagonist (IL-1ra), bosentan [a dual endothelin (ET)A/ETB receptor antagonist], clazosentan (an ETA receptor antagonist), or indomethacin (a cyclooxygenase inhibitor). IL-33 induced hypernociception in IL-18−/− mice but not in TNFR1−/− or IFNγ−/− mice. The IL-33-induced hypernociception was not affected by blocking IL-15 or sympathetic amines (guanethidine). Furthermore, methylated BSA (mBSA)-induced cutaneous and articular mechanical hypernociception depended on TNFR1 and IFNγ and was blocked by sST2, IL-1ra, bosentan, clazosentan, and indomethacin. mBSA also induced significant IL-33 and ST2 mRNA expression. Importantly, we showed that mBSA induced hypernociception via the IL-33 → TNFα → IL-1β → IFNγ → ET-1 → PGE2 signaling cascade. These results therefore demonstrate that IL-33 is a key mediator of immune inflammatory hypernociception normally associated with a Th1 type of response, revealing a hitherto unrecognized function of IL-33 in a key immune pharmacological pathway that may be amenable to therapeutic intervention. PMID:18250323

  11. Peripheral NMDA Receptors Mediate Antidromic Nerve Stimulation-Induced Tactile Hypersensitivity in the Rat

    PubMed Central

    Jang, Jun Ho; Nam, Taick Sang; Jun, Jaebeom; Jung, Se Jung; Kim, Dong-Wook; Leem, Joong Woo

    2015-01-01

    We investigated the role of peripheral NMDA receptors (NMDARs) in antidromic nerve stimulation-induced tactile hypersensitivity outside the skin area innervated by stimulated nerve. Tetanic electrical stimulation (ES) of the decentralized L5 spinal nerve, which induced enlargement of plasma extravasation, resulted in tactile hypersensitivity in the L4 plantar dermatome of the hind-paw. When intraplantar (i.pl.) injection was administered into the L4 dermatome before ES, NMDAR and group-I metabotropic Glu receptor (mGluR) antagonists and group-II mGluR agonist but not AMPA/kainate receptor antagonist prevented ES-induced hypersensitivity. I.pl. injection of PKA or PKC inhibitors also prevented ES-induced hypersensitivity. When the same injections were administered after establishment of ES-induced hypersensitivity, hypersensitivity was partially reduced by NMDAR antagonist only. In naïve animals, i.pl. Glu injection into the L4 dermatome induced tactile hypersensitivity, which was blocked by NMDAR antagonist and PKA and PKC inhibitors. These results suggest that the peripheral release of Glu, induced by antidromic nerve stimulation, leads to the expansion of tactile hypersensitive skin probably via nociceptor sensitization spread due to the diffusion of Glu into the skin near the release site. In addition, intracellular PKA- and PKC-dependent mechanisms mediated mainly by NMDAR activation are involved in Glu-induced nociceptor sensitization and subsequent hypersensitivity. PMID:26770021

  12. NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression

    SciTech Connect

    Li, Ruizhao; Zhang, Li; Shi, Wei; Zhang, Bin; Liang, Xinling; Liu, Shuangxin; Wang, Wenjian

    2013-04-15

    Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca{sup 2+} was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca{sup 2+}]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway

  13. Lysophosphatidic acid induces vasodilation mediated by LPA1 receptors, phospholipase C, and endothelial nitric oxide synthase

    PubMed Central

    Ruisanchez, Éva; Dancs, Péter; Kerék, Margit; Németh, Tamás; Faragó, Bernadett; Balogh, Andrea; Patil, Renukadevi; Jennings, Brett L.; Liliom, Károly; Malik, Kafait U.; Smrcka, Alan V.; Tigyi, Gabor; Benyó, Zoltán

    2014-01-01

    Lysophosphatidic acid (LPA) has been implicated as a mediator of several cardiovascular functions, but its potential involvement in the control of vascular tone is obscure. Here, we show that both LPA (18:1) and VPC31143 (a synthetic agonist of LPA1–3 receptors) relax intact mouse thoracic aorta with similar Emax values (53.9 and 51.9% of phenylephrine-induced precontraction), although the EC50 of LPA- and VPC31143-induced vasorelaxations were different (400 vs. 15 nM, respectively). Mechanical removal of the endothelium or genetic deletion of endothelial nitric oxide synthase (eNOS) not only diminished vasorelaxation by LPA or VPC31143 but converted it to vasoconstriction. Freshly isolated mouse aortic endothelial cells expressed LPA1, LPA2, LPA4 and LPA5 transcripts. The LPA1,3 antagonist Ki16425, the LPA1 antagonist AM095, and the genetic deletion of LPA1, but not that of LPA2, abolished LPA-induced vasorelaxation. Inhibition of the phosphoinositide 3 kinase–protein kinase B/Akt pathway by wortmannin or MK-2206 failed to influence the effect of LPA. However, pharmacological inhibition of phospholipase C (PLC) by U73122 or edelfosine, but not genetic deletion of PLCε, abolished LPA-induced vasorelaxation and indicated that a PLC enzyme, other than PLCε, mediates the response. In summary, the present study identifies LPA as an endothelium-dependent vasodilator substance acting via LPA1, PLC, and eNOS.—Ruisanchez, É., Dancs, P., Kerék, M., Németh, T., Faragó, B., Balogh, A., Patil, R., Jennings, B. L., Liliom, K., Malik, K. U., Smrcka, A. V., Tigyi, G., Benyó, Z. Lysophosphatidic acid induces vasodilation mediated by LPA1 receptors, phospholipase C, and endothelial nitric oxide synthase. PMID:24249637

  14. Mast cells mediate the immune suppression induced by dermal exposure to JP-8 jet fuel.

    PubMed

    Limón-Flores, Alberto Y; Chacón-Salinas, Rommel; Ramos, Gerardo; Ullrich, Stephen E

    2009-11-01

    Applying jet propulsion-8 (JP-8) jet fuel to the skin of mice induces immune suppression. Applying JP-8 to the skin of mice suppresses T-cell-mediated immune reactions including, contact hypersensitivity (CHS) delayed-type hypersensitivity and T-cell proliferation. Because dermal mast cells play an important immune regulatory role in vivo, we tested the hypothesis that mast cells mediate jet fuel-induced immune suppression. When we applied JP-8 to the skin of mast cell deficient mice CHS was not suppressed. Reconstituting mast cell deficient mice with wild-type bone marrow derived mast cells (mast cell "knock-in mice") restored JP-8-induced immune suppression. When, however, mast cells from prostaglandin E(2) (PGE(2))-deficient mice were used, the ability of JP-8 to suppress CHS was not restored, indicating that mast cell-derived PGE(2) was activating immune suppression. Examining the density of mast cells in the skin and lymph nodes of JP-8-treated mice indicated that jet fuel treatment caused an initial increase in mast cell density in the skin, followed by increased numbers of mast cells in the subcutaneous space and then in draining lymph nodes. Applying JP-8 to the skin increased mast cell expression of CXCR4, and increased the expression of CXCL12 by draining lymph node cells. Because CXCL12 is a chemoattractant for CXCR4+ mast cells, we treated JP-8-treated mice with AMD3100, a CXCR4 antagonist. AMD3100 blocked the mobilization of mast cells to the draining lymph node and inhibited JP-8-induced immune suppression. Our findings demonstrate the importance of mast cells in mediating jet fuel-induced immune suppression. PMID:19726579

  15. The silent and selective 5-HT1A antagonist, WAY 100635, produces via an indirect mechanism, a 5-HT2A receptor-mediated behaviour in mice during the day but not at night. Short communication.

    PubMed

    Darmani, N A

    1998-01-01

    The head-twitch response (HTR) in rodents is considered to be a functional index for the activation of 5-HT2A receptors. Intraperitoneal administration of the silent and selective 5-HT1A receptor antagonist, WAY 100635, produced the HTR in mice in a dose-dependent bell-shaped manner. The induced behaviour followed a diurnal pattern in that WAY 100635 only produced a robust HTR frequency during the light period of the 24h daily cycle. Pretreatment with the selective 5-HT2A/C receptor antagonist, SR 46349B, potently, and in a dose-dependent manner attenuated the induced behaviour. It appears that WAY 100635 produces the HTR indirectly via disinhibition of endogenous serotonergic inhibitory tone operating on the somatodenritic pulse-modulating 5-HT1A autoreceptors. The latter antagonism seems to potentiate endogenous 5-HT release in serotonergic terminal field synapses which subsequently stimulates postsynaptic 5-HT2A receptors to produce the head-twitch behaviour. PMID:9826108

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

    SciTech Connect

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

    2012-03-01

    The placenta is essential for sustaining the growth of the fetus. An increased endoplasmic reticulum (ER) stress has been associated with the impaired placental and fetal development. Cadmium (Cd) is a potent teratogen that caused fetal malformation and growth restriction. The present study investigated the effects of maternal Cd exposure on placental and fetal development. The pregnant mice were intraperitoneally injected with CdCl{sub 2} (4.5 mg/kg) on gestational day 9. As expected, maternal Cd exposure during early limb development significantly increased the incidences of forelimb ectrodactyly in fetuses. An obvious impairment in the labyrinth, a highly developed tissue of blood vessels, was observed in placenta of mice treated with CdCl{sub 2}. In addition, maternal Cd exposure markedly repressed cell proliferation and increased apoptosis in placenta. An additional experiment showed that maternal Cd exposure significantly upregulated the expression of GRP78, an ER chaperone. Moreover, maternal Cd exposure induced the phosphorylation of placental eIF2α, a downstream molecule of PERK signaling. In addition, maternal Cd exposure significantly increased the level of placental CHOP, another target of PERK signaling, indicating that the unfolded protein response (UPR) signaling was activated in placenta of mice treated with CdCl{sub 2}. Interestingly, alpha-phenyl-N-t-butylnitrone, a free radical spin-trapping agent, significantly alleviated Cd-induced placental ER stress and UPR. Taken together, these results suggest that reactive oxygen species (ROS)-mediated ER stress might be involved in Cd-induced impairment on placental and fetal development. Antioxidants may be used as pharmacological agents to protect against Cd-induced fetal malformation and growth restriction. -- Highlights: ► Cd induces fetal malformation and growth restriction. ► Cd induced placental ER stress and UPR. ► PBN alleviates Cd-induced ER stress and UPR in placenta. ► ROS-mediated ER

  17. Induced resistance to periwinkle grazing in the brown seaweed Fucus vesiculosus (Phaeophyceae): molecular insights and seaweed-mediated effects on herbivore interactions.

    PubMed

    Flöthe, Carla R; Molis, Markus; John, Uwe

    2014-06-01

    Herbivory is a key factor for controlling seaweed biomass and community structure. To cope with grazers, constitutive and inducible defenses have evolved in macroalgae. Inducible chemical defenses show grazer-specificity and, at the same time, have the potential to mediate interactions among different herbivores. Furthermore, temporal variations in defense patterns, which may adjust antiherbivory responses to grazing pressure, were reported in two brown seaweeds. However, underlying cellular processes are only rudimentarily characterized. To investigate the response of Fucus vesiculosus (L.) to periwinkle (Littorina obtusata) grazing, feeding assays were conducted at several times during a 33 d induction experiment. Underlying cellular processes were analyzed through gene expression profiling. Furthermore, direct processes driving the antiherbivory response to periwinkle grazing and indirect effects on another herbivore, the isopod Idotea baltica, were elucidated. F. vesiculosus showed multiple defense pulses in response to periwinkle grazing, suggesting a high level of temporal variability in antiherbivory traits. Defense induction was accompanied by extensive transcriptome changes. Approximately 400 genes were significantly up-/down-regulated relative to controls, including genes relevant for translation and the cytoskeleton. Genes involved in photosynthesis were mostly down-regulated, while genes related to the respiratory chain were up-regulated, indicating alterations in resource allocation. The comparison of genes regulated in response to isopod (previous study) and periwinkle grazing suggests specific induction of several genes by each herbivore. However, grazing by both herbivores induced similar metabolic processes in F. vesiculosus. These common defense-related processes reflected in strong indirect effects as isopods were also repelled after previous grazing by L. obtusata. PMID:26988328

  18. Posterodorsal Medial Amygdala Mediates Tail-Pinch Induced Food Intake in Female Rats.

    PubMed

    Hu, M H; Bashir, Z; Li, X F; O'Byrne, K T

    2016-05-01

    Comfort eating during periods of stress is a common phenomenon observed in both animals and humans. However, the underlying mechanisms of stress-induced food intake remain elusive. The amygdala plays a central role in higher-order emotional processing and the posterodorsal subnucleus of the medial amygdala (MePD), in particular, is involved in food intake. Extra-hypothalamic corticotrophin-releasing factor (CRF) is well recognised for mediating behavioural responses to stress. To explore the possible role of amygdala CRF receptor activation in stress-induced food intake, we evaluated whether a stressor such as tail-pinch, which reliably induces food intake, would fail to do so in animals bearing bilateral neurotoxic lesions of the MePD. Our results showed that ibotenic acid induced lesions of the MePD markedly reduced tail-pinch induced food intake in ovariectomised, 17β-oestradiol replaced rats. In addition, intra-MePD (right side only) administration of CRF (0.002 or 0.02 ng) via chronically implanted cannulae resulted in a dose-dependent increase in food intake, although higher doses of 0.2 and 2 ng CRF had less effect, producing a bell shaped curve. Furthermore, intra-MePD (bilateral) administration of the CRF receptor antagonist, astressin (0.3 μg per side) effectively blocked tail-pinch induced food intake. These data suggest that the MePD is involved in stress-induced food intake and that the amygdala CRF system may be a mediator of comfort eating. PMID:27028781

  19. Analysis of methods and models for assessing the direct and indirect economic impacts of CO/sub 2/-induced environmental changes in the agricultural sector of the US economy

    SciTech Connect

    Callaway, J.M.

    1982-08-01

    Alternative methods for quantifying the economic impacts associated with future increases in the ambient concentration of CO/sub 2/ were examined. A literature search was undertaken, both to gain a better understanding of the ways in which CO/sub 2/ buildup could affect crop growth and to identify the different methods available for assessing the impacts of CO/sub 2/-induced environmental changes on crop yields. The second task involved identifying the scope of both the direct and indirect economic impacts that could occur as a result of CO/sub 2/-induced changes in crop yields. The third task then consisted of a comprehensive literature search to identify what types of economic models could be used effectively to assess the kinds of direct and indirect economic impacts that could conceivably occur as a result of CO/sub 2/ buildup. Specific attention was focused upon national and multi-regional agricultural sector models, multi-country agricultural trade models, and macroeconomic models of the US economy. The fourth and final task of this research involved synthesizing the information gathered in the previous tasks into a systematic framework for assessing the direct and indirect economic impacts of CO/sub 2/-induced environmental changes related to agricultural production.

  20. Hypoxia-induced autophagy mediates cisplatin resistance in lung cancer cells

    PubMed Central

    Wu, Hui-Mei; Jiang, Zi-Feng; Ding, Pei-Shan; Shao, Li-Jie; Liu, Rong-Yu

    2015-01-01

    Hypoxia which commonly exists in solid tumors, leads to cancer cells chemoresistance via provoking adaptive responses including autophagy. Therefore, we sought to evaluate the role of autophagy and hypoxia as well as the underlying mechanism in the cisplatin resistance of lung cancer cells. Our study demonstrated that hypoxia significantly protected A549 and SPC-A1 cells from cisplatin-induced cell death in a Hif-1α- and Hif-2α- dependent manner. Moreover, compared with normoxia, cisplatin-induced apoptosis under hypoxia was markedly reduced. However, when autophagy was inhibited by 3-MA or siRNA targeted ATG5, this reduction was effectively attenuated, which means autophagy mediates cisplatin resisitance under hypoxia. In parallel, we showed that hypoxia robustly augmented cisplatin-induced autophagy activation, accompanying by suppressing cisplatin-induced BNIP3 death pathways, which was due to the more efficient autophagic process under hypoxia. Consequently, we proposed that autophagy was a protective mechanism after cisplatin incubation under both normoxia and hypoxia. However, under normoxia, autophagy activation ‘was unable to counteract the stress induced by cisplatin, therefore resulting in cell death, whereas under hypoxia, autophagy induction was augmented that solved the cisplatin-induced stress, allowing the cells to survival. In conclusion, augmented induction of autophagy by hypoxia decreased lung cancer cells susceptibility to cisplatin-induced apoptosis. PMID:26201611

  1. ROS and Sympathetically Mediated Mitochondria Activation in Brown Adipose Tissue Contribute to Methamphetamine-Induced Hyperthermia

    PubMed Central

    Sanchez-Alavez, Manuel; Conti, Bruno; Wood, Malcolm R.; Bortell, Nikki; Bustamante, Eduardo; Saez, Enrique; Fox, Howard S.; Marcondes, Maria Cecilia Garibaldi

    2013-01-01

    Methamphetamine (Meth) abuse has been shown to induce alterations in mitochondrial function in the brain as well as to induce hyperthermia, which contributes to neurotoxicity and Meth-associated mortality. Brown adipose tissue (BAT), a thermogenic site known to be important in neonates, has recently regained importance since being identified in significant amounts and in correlation with metabolic balance in human adults. Given the high mitochondrial content of BAT and its role in thermogenesis, we aimed to investigate whether BAT plays any role in the development of Meth-induced hyperthermia. By ablating or denervating BAT, we identified a partial contribution of this organ to Meth-induced hyperthermia. BAT ablation decreased temperature by 0.5°C and reduced the length of hyperthermia by 1 h, compared to sham-operated controls. BAT denervation also affected the development of hyperthermia in correlation with decreased the expression of electron transport chain molecules, and increase on PCG1a levels, but without affecting Meth-induced uncoupling protein 1 upregulation. Furthermore, in isolated BAT cells in culture, Meth, but not Norepinephrine, induced H2O2 upregulation. In addition, we found that in vivo Reactive Oxygen Species (ROS) play a role in Meth hyperthermia. Thus, sympathetically mediated mitochondrial activation in the BAT and Meth-induced ROS are key components to the development of hyperthermia in Meth abuse. PMID:23630518

  2. Saturated phosphatidic acids mediate saturated fatty acid–induced vascular calcification and lipotoxicity

    PubMed Central

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L.; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M.; Kuro-o, Makoto; Miyazaki, Makoto

    2015-01-01

    Recent evidence indicates that saturated fatty acid–induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification. PMID:26517697

  3. Saturated phosphatidic acids mediate saturated fatty acid-induced vascular calcification and lipotoxicity.

    PubMed

    Masuda, Masashi; Miyazaki-Anzai, Shinobu; Keenan, Audrey L; Okamura, Kayo; Kendrick, Jessica; Chonchol, Michel; Offermanns, Stefan; Ntambi, James M; Kuro-O, Makoto; Miyazaki, Makoto

    2015-12-01

    Recent evidence indicates that saturated fatty acid-induced (SFA-induced) lipotoxicity contributes to the pathogenesis of cardiovascular and metabolic diseases; however, the molecular mechanisms that underlie SFA-induced lipotoxicity remain unclear. Here, we have shown that repression of stearoyl-CoA desaturase (SCD) enzymes, which regulate the intracellular balance of SFAs and unsaturated FAs, and the subsequent accumulation of SFAs in vascular smooth muscle cells (VSMCs), are characteristic events in the development of vascular calcification. We evaluated whether SMC-specific inhibition of SCD and the resulting SFA accumulation plays a causative role in the pathogenesis of vascular calcification and generated mice with SMC-specific deletion of both Scd1 and Scd2. Mice lacking both SCD1 and SCD2 in SMCs displayed severe vascular calcification with increased ER stress. Moreover, we employed shRNA library screening and radiolabeling approaches, as well as in vitro and in vivo lipidomic analysis, and determined that fully saturated phosphatidic acids such as 1,2-distearoyl-PA (18:0/18:0-PA) mediate SFA-induced lipotoxicity and vascular calcification. Together, these results identify a key lipogenic pathway in SMCs that mediates vascular calcification. PMID:26517697

  4. Ghrelin mediates stress-induced food-reward behavior in mice.

    PubMed

    Chuang, Jen-Chieh; Perello, Mario; Sakata, Ichiro; Osborne-Lawrence, Sherri; Savitt, Joseph M; Lutter, Michael; Zigman, Jeffrey M

    2011-07-01

    The popular media and personal anecdotes are rich with examples of stress-induced eating of calorically dense "comfort foods." Such behavioral reactions likely contribute to the increased prevalence of obesity in humans experiencing chronic stress or atypical depression. However, the molecular substrates and neurocircuits controlling the complex behaviors responsible for stress-based eating remain mostly unknown, and few animal models have been described for probing the mechanisms orchestrating this response. Here, we describe a system in which food-reward behavior, assessed using a conditioned place preference (CPP) task, is monitored in mice after exposure to chronic social defeat stress (CSDS), a model of prolonged psychosocial stress, featuring aspects of major depression and posttraumatic stress disorder. Under this regime, CSDS increased both CPP for and intake of high-fat diet, and stress-induced food-reward behavior was dependent on signaling by the peptide hormone ghrelin. Also, signaling specifically in catecholaminergic neurons mediated not only ghrelin's orexigenic, antidepressant-like, and food-reward behavioral effects, but also was sufficient to mediate stress-induced food-reward behavior. Thus, this mouse model has allowed us to ascribe a role for ghrelin-engaged catecholaminergic neurons in stress-induced eating. PMID:21701068

  5. Maresin 1, a Proresolving Lipid Mediator, Mitigates Carbon Tetrachloride-Induced Liver Injury in Mice

    PubMed Central

    Li, Ruidong; Wang, Yaxin; Zhao, Ende; Wu, Ke; Li, Wei; Shi, Liang; Wang, Di; Xie, Gengchen; Yin, Yuping; Deng, Meizhou; Zhang, Peng; Tao, Kaixiong

    2016-01-01

    Maresin 1 (MaR 1) was recently reported to have protective properties in several different animal models of acute inflammation by inhibiting inflammatory response. However, its function in acute liver injury is still unknown. To address this question, we induced liver injury in BALB/c mice with intraperitoneal injection of carbon tetrachloride with or without treatment of MaR 1. Our data showed that MaR 1 attenuated hepatic injury, oxidative stress, and lipid peroxidation induced by carbon tetrachloride, as evidenced by increased thiobarbituric acid reactive substances and reactive oxygen species levels were inhibited by treatment of MaR 1. Furthermore, MaR 1 increased activities of antioxidative mediators in carbon tetrachloride-treated mice liver. MaR 1 decreased indices of inflammatory mediators such as tumor necrosis factor-α, interleukin-6, interleukin-1β, monocyte chemotactic protein 1, myeloperoxidase, cyclooxygenase-2, and inducible nitric oxide synthase. Administration of MaR 1 inhibited activation of nuclear factor kappa B (NF-κb) and mitogen-activated protein kinases (MAPKs) in the liver of CCl4 treated mice. In conclusion, these results suggested the antioxidative, anti-inflammatory properties of MaR 1 in CCl4 induced liver injury. The possible mechanism is partly implicated in its abilities to inhibit ROS generation and activation of NF-κb and MAPK pathway. PMID:26881046

  6. Unconjugated bilirubin mediates heme oxygenase-1-induced vascular benefits in diabetic mice.

    PubMed

    Liu, Jian; Wang, Li; Tian, Xiao Yu; Liu, Limei; Wong, Wing Tak; Zhang, Yang; Han, Quan-Bin; Ho, Hing-Man; Wang, Nanping; Wong, Siu Ling; Chen, Zhen-Yu; Yu, Jun; Ng, Chi-Fai; Yao, Xiaoqiang; Huang, Yu

    2015-05-01

    Heme oxygenase-1 (HO-1) exerts vasoprotective effects. Such benefit in diabetic vasculopathy, however, remains unclear. We hypothesize that bilirubin mediates HO-1-induced vascular benefits in diabetes. Diabetic db/db mice were treated with hemin (HO-1 inducer) for 2 weeks, and aortas were isolated for functional and molecular assays. Nitric oxide (NO) production was measured in cultured endothelial cells. Hemin treatment augmented endothelium-dependent relaxations (EDRs) and elevated Akt and endothelial NO synthase (eNOS) phosphorylation in db/db mouse aortas, which were reversed by the HO-1 inhibitor SnMP or HO-1 silencing virus. Hemin treatment increased serum bilirubin, and ex vivo bilirubin treatment improved relaxations in diabetic mouse aortas, which was reversed by the Akt inhibitor. Biliverdin reductase silencing virus attenuated the effect of hemin. Chronic bilirubin treatment improved EDRs in db/db mouse aortas. Hemin and bilirubin reversed high glucose-induced reductions in Akt and eNOS phosphorylation and NO production. The effect of hemin but not bilirubin was inhibited by biliverdin reductase silencing virus. Furthermore, bilirubin augmented EDRs in renal arteries from diabetic patients. In summary, HO-1-induced restoration of endothelial function in diabetic mice is most likely mediated by bilirubin, which preserves NO bioavailability through the Akt/eNOS/NO cascade, suggesting bilirubin as a potential therapeutic target for clinical intervention of diabetic vasculopathy. PMID:25475440

  7. Sodium hydrogen exchanger as a mediator of hydrostatic edema induced intestinal contractile dysfunction

    PubMed Central

    Uray, Karen S.; Shah, Shinil K.; Radhakrishnan, Ravi S.; Jimenez, Fernando; Walker, Peter A.; Stewart, Randolph H.; Laine, Glen A.; Cox, Charles S.

    2010-01-01

    Background Resuscitation-induced intestinal edema is associated with early and profound mechanical changes in intestinal tissue. We hypothesize that the sodium hydrogen exchanger (NHE), a mechano-responsive ion channel, is a mediator of edema-induced intestinal contractile dysfunction. Methods An animal model of hydrostatic intestinal edema was utilized for all experiments. NHE isoforms 1-3 mRNA and protein were evaluated. Subsequently, the effects of NHE inhibition (with 5-(N-ethyl-N-isopropyl) amiloride (EIPA)) on wet to dry ratios, signal transduction and activator of transcription (STAT)-3, intestinal smooth muscle myosin light chain (MLC) phosphorylation, intestinal contractile activity, and intestinal transit were measured. Results NHE1-3 mRNA and protein levels were significantly increased in the small intestinal mucosa with the induction of intestinal edema. Administration of EIPA, an NHE inhibitor, attenuated validated markers of intestinal contractile dysfunction induced by edema as measured by decreased STAT-3 activation, increased MLC phosphorylation, improved intestinal contractile activity, and enhanced intestinal transit. Conclusion The mechano-responsive ion channel NHE may mediate edema-induced intestinal contractile dysfunction, possibly via a STAT-3 related mechanism. PMID:20553904

  8. Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation

    SciTech Connect

    Nagata, Yosuke Ohashi, Kazuya; Wada, Eiji; Yuasa, Yuki; Shiozuka, Masataka; Nonomura, Yoshiaki; Matsuda, Ryoichi

    2014-08-01

    Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor. - Highlights: • EGF in combination with insulin induces proliferation of quiescent C2C12 cells. • Sphingosine kinase activity increases when reserve cells are stimulated with EGF. • EGF-induced activation of reserve cells is dependent on sphingosine kinase and ERK. • The S1P receptor S1P2 is involved in EGF-induced reserve cell activation. • EGF-induced reserve cell activation is mediated by S1P and its

  9. Epigallocatechin gallate (EGCG) attenuates infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation.

    PubMed

    Cai, Jing; Jing, Da; Shi, Ming; Liu, Yang; Lin, Tian; Xie, Zhen; Zhu, Yi; Zhao, Haibo; Shi, Xiaodan; Du, Fang; Zhao, Gang

    2014-07-01

    Infrasound, a kind of common environmental noise and a major contributor of vibroacoustic disease, can induce the central nervous system (CNS) damage. However, no relevant anti-infrasound drugs have been reported yet. Our recent studies have shown that infrasound resulted in excessive microglial activation rapidly and sequential inflammation, revealing a potential role of microglia in infrasound-induced CNS damage. Epigallocatechin gallate (EGCG), a major bioactive component in green tea, has the capacity of protecting against various neurodegenerative diseases via an anti-inflammatory mechanism. However, it is still unknown to date whether EGCG acts on infrasound-induced microglial activation and neuronal damage. We showed that, after 1-, 2- or 5-day exposure of rats to 16 Hz, 130 dB infrasound (2 h/day), EGCG significantly inhibited infrasound-induced microglial activation in rat hippocampal region, evidenced by reduced expressions of Iba-1 (a marker for microglia) and proinflammatory cytokines (IL-1β, IL-6, IL-18 and TNF-α). Moreover, infrasound-induced neuronal apoptosis in rat hippocampi was significantly suppressed by EGCG. EGCG also inhibited infrasound-induced activation of primary microglia in vitro and decreased the levels of proinflammatory cytokines in the supernatants of microglial culture, which were toxic to cultured neurons. Furthermore, EGCG attenuated infrasound-induced increases in nuclear NF-κB p65 and phosphorylated IκBα, and ameliorated infrasound-induced decrease in IκB in microglia. Therefore, our study provides the first evidence that EGCG acts against infrasound-induced neuronal impairment by inhibiting microglia-mediated inflammation through a potential NF-κB pathway-related mechanism, suggesting that EGCG can be used as a promising drug for the treatment of infrasound-induced CNS damage. PMID:24746834

  10. A simple method to prevent hard X-ray-induced preheating effects inside the cone tip in indirect-drive fast ignition implosions

    NASA Astrophysics Data System (ADS)

    Liu, Dongxiao; Shan, Lianqiang; Zhou, Weimin; Wu, Yuchi; Zhu, Bin; Peng, Xiaoshi; Xu, Tao; Wang, Feng; Zhang, Feng; Bi, Bi; Zhang, Bo; Zhang, Zhimeng; Shui, Min; He, Yingling; Yang, Zhiwen; Chen, Tao; Chen, Li; Chen, Ming; Yang, Yimeng; Yuan, Yongteng; Wang, Peng; Gu, Yuqiu; Zhang, Baohan

    2016-06-01

    During fast-ignition implosions, preheating of inside the cone tip caused by hard X-rays can strongly affect the generation and transport of hot electrons in the cone. Although indirect-drive implosions have a higher implosion symmetry, they cause stronger preheating effects than direct-drive implosions. To control the preheating of the cone tip, we propose the use of indirect-drive fast-ignition targets with thicker tips. Experiments carried out at the ShenGuang-III prototype laser facility confirmed that thicker tips are effective for controlling preheating. Moreover, these results were consistent with those of 1D radiation hydrodynamic simulations.

  11. Nicotine-Mediated Ca(2+)-Influx Induces IL-8 Secretion in Oral Squamous Cell Carcinoma Cell.

    PubMed

    Tsunoda, Kou; Tsujino, Ichiro; Koshi, Ryosuke; Sugano, Naoyuki; Sato, Shuichi; Asano, Masatake

    2016-04-01

    Cigarette smoking is one of the most important risk factors for the development of various diseases. Nicotine is the most extensively investigated component of cigarette smoke, and a comprehensive analysis of the genes induced by nicotine stimulation revealed that interleukin-8 (IL-8) was induced in oral squamous cell carcinoma cell (OSCC). Based on this background, the signaling mechanisms of nicotine-mediated IL-8 induction in OSCC was investigated. Augmented IL-8 secretion by Ca9-22 cells was blocked by the NF-κB inhibitor L-1-4'-tosylamino-phenylethyl-chloromethyl ketone (TPCK) and the nicotinic acetylcholine receptor (nAChR)-specific inhibitor α-bungarotoxin (αBtx). The downstream signaling pathway was further examined by pre-incubating the cells with inhibitors against mitogen-activated protein kinase (MEK), protein kinase C (PKC), and Ca(2+)/calmodulin-dependent kinase II (CaMK II). Only the CaMK II inhibitor was found to exert an inhibitory effect on nicotine-mediated IL-8 secretion. Pre-treatment of the Ca9-22 cells with the Ca(2+) chelator BAPTA-AM drastically inhibited IL-8 secretion. Although nicotine stimulation induced the phosphorylation of the NF-κB p65 subunit, pre-treatment with BAPTA-AM was found to inhibit this activity significantly. CaMK II-dependent p65 phosphorylation was confirmed by pre-incubation of the cells with CaMK II inhibitor. The results from this study indicate that the binding of nicotine to nAChR induces Ca(2+) influx, which results in the activation and phosphorylation of CaMK II and NF-κB p65, respectively. Nicotine-mediated IL-8 induction should be a trigger for the initiation of various diseases. PMID:26418512

  12. Kupffer cell-mediated exacerbation of methimazole-induced acute liver injury in rats.

    PubMed

    Akai, Sho; Uematsu, Yasuaki; Tsuneyama, Koichi; Oda, Shingo; Yokoi, Tsuyoshi

    2016-05-01

    Methimazole (MTZ), an anti-thyroid drug, is known to cause liver injury in humans. It has been demonstrated that MTZ-induced liver injury in Balb/c mice is accompanied by T helper (Th) 2 cytokine-mediated immune responses; however, there is little evidence for immune responses associated with MTZ-induced liver injury in rats. To investigate species differences in MTZ-induced liver injury, we administered MTZ with a glutathione biosynthesis inhibitor, L-buthionine-S,R-sulfoximine (BSO), to F344 rats and subsequently observed an increase in plasma alanine aminotransferase (ALT) and high-mobility group box 1 (HMGB1), which are associated with hepatic lesions. The hepatic mRNA expression of innate immune-related genes significantly increased in BSO- and MTZ-treated rats, but the change in Th2-related genes was not much greater than the change observed in the previous mouse study. Moreover, an increase in Kupffer cells and an induction of the phosphorylation of extracellular signal-regulated kinase (ERK)/c-Jun N-terminal kinase (JNK) proteins were accompanied by an increase in Toll-like receptor 4 (TLR4) expression, indicating that Kupffer cell activation occurs through HMGB1-TLR4 signaling. To elucidate the mechanism of liver injury in rats, gadolinium chloride, which inactivates the function of Kupffer cells, was administered before BSO and MTZ administration. The gadolinium chloride treatment significantly suppressed the increased ALT, which was accompanied by decreased hepatic mRNA expression related to innate immune responses and ERK/JNK phosphorylation. In conclusion, Kupffer cell-mediated immune responses are crucial factors for the exacerbation of MTZ-induced liver injury in rats, indicating apparent species differences in the immune-mediated exacerbation of liver injury between mice and rats. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26177832

  13. SCO2 Mediates Oxidative Stress-Induced Glycolysis to Oxidative Phosphorylation Switch in Hematopoietic Stem Cells.

    PubMed

    Du, Wei; Amarachintha, Surya; Wilson, Andrew F; Pang, Qishen

    2016-04-01

    Fanconi anemia (FA) is an inherited bone marrow (BM) failure syndrome, presumably resulting from defects in hematopoietic stem cells (HSCs). Normal HSCs depend more on glycolysis than on oxidative phosphorylation (OXPHOS) for energy production. Here, we show that FA HSCs are more sensitive to the respiration inhibitor NaN3 treatment than to glycolytic inhibitor 2-deoxy-d-glucose (2-DG), indicating more dependence on OXPHOS. FA HSCs undergo glycolysis-to-OXPHOS switch in response to oxidative stress through a p53-dependent mechanism. Metabolic stresses induce upregulation of p53 metabolic targets in FA HSCs. Inactivation of p53 in FA HSCs prevents glycolysis-to-OXPHOS switch. Furthermore, p53-deficient FA HSCs are more sensitive to 2-DG-mediated metabolic stress. Finally, oxidative stress-induced glycolysis-to-OXPHOS switch is mediated by synthesis of cytochrome c oxidase 2 (SCO2). These findings demonstrate p53-mediated OXPHOS function as a compensatory alteration in FA HSCs to ensure a functional but mildly impaired energy metabolism and suggest a cautious approach to manipulating p53 signaling in FA. Stem Cells 2016;34:960-971. PMID:26676373

  14. Silver Nanoparticles Induce HePG-2 Cells Apoptosis Through ROS-Mediated Signaling Pathways.

    PubMed

    Zhu, Bing; Li, Yinghua; Lin, Zhengfang; Zhao, Mingqi; Xu, Tiantian; Wang, Changbing; Deng, Ning

    2016-12-01

    Recently, silver nanoparticles (AgNPs) have been shown to provide a novel approach to overcome tumors, especially those of hepatocarcinoma. However, the anticancer mechanism of silver nanoparticles is unclear. Thus, the purpose of this study was to estimate the effect of AgNPs on proliferation and activation of ROS-mediated signaling pathway on human hepatocellular carcinoma HePG-2 cells. A simple chemical method for preparing AgNPs with superior anticancer activity has been showed in this study. AgNPs were detected by transmission electronic microscopy (TEM) and energy dispersive X-ray (EDX). The size distribution and zeta potential of silver nanoparticles were detected by Zetasizer Nano. The average size of AgNPs (2 nm) observably increased the cellular uptake by endocytosis. AgNPs markedly inhibited the proliferation of HePG-2 cells through induction of apoptosis with caspase-3 activation and PARP cleavage. AgNPs with dose-dependent manner significantly increased the apoptotic cell population (sub-G1). Furthermore, AgNP-induced apoptosis was found dependent on the overproduction of reactive oxygen species (ROS) and affecting of MAPKs and AKT signaling and DNA damage-mediated p53 phosphorylation to advance HePG-2 cells apoptosis. Therefore, our results show that the mechanism of ROS-mediated signaling pathways may provide useful information in AgNP-induced HePG-2 cell apoptosis. PMID:27075340

  15. RNA-induced silencing attenuates G protein-mediated calcium signals.

    PubMed

    Philip, Finly; Sahu, Shriya; Golebiewska, Urszula; Scarlata, Suzanne

    2016-05-01

    Phospholipase Cβ (PLCβ) is activated by G protein subunits in response to environmental stimuli to increase intracellular calcium. In cells, a significant portion of PLCβ is cytosolic, where it binds a protein complex required for efficient RNA-induced silencing called C3PO (component 3 promoter of RISC). Binding between C3PO and PLCβ raises the possibility that RNA silencing activity can affect the ability of PLCβ to mediate calcium signals. By use of human and rat neuronal cell lines (SK-N-SH and PC12), we show that overexpression of one of the main components of C3PO diminishes Ca(2+) release in response to Gαq/PLCβ stimulation by 30 to 40%. In untransfected SK-N-SH or PC12 cells, the introduction of siRNA(GAPDH) [small interfering RNA(glyceraldehyde 3-phosphate dehydrogenase)] reduces PLCβ-mediated calcium signals by ∼30%, but addition of siRNA(Hsp90) (heat shock protein 90) had little effect. Fluorescence imaging studies suggest an increase in PLCβ-C3PO association in cells treated with siRNA(GAPDH) but not siRNA(Hsp90). Taken together, our studies raise the possibility that Ca(2+) responses to extracellular stimuli can be modulated by components of the RNA silencing machinery.-Philip, F., Sahu, S., Golebiewska, U., Scarlata, S. RNA-induced silencing attenuates G protein-mediated calcium signals. PMID:26862135

  16. MCM2 mediates progesterone-induced endometrial stromal cell proliferation and differentiation in mice.

    PubMed

    Kong, Shuangbo; Han, Xue; Cui, Tongtong; Zhou, Chan; Jiang, Yufei; Zhang, Hangxiao; Wang, Bingyan; Wang, Haibin; Zhang, Shuang

    2016-08-01

    Uterine decidualization characterized by stromal cell proliferation and differentiation is critical to the establishment of pregnancy in many species. Progesterone is a key factor in regulating endometrial cell decidualization, however, the molecular basis involved in mediating the effects of progesterone during decidualization remains largely unknown. We report here that the DNA replication licensing factor MCM2, one of the conserved set of six-related proteins (MCM complex: MCM2-7) essential for eukaryotic DNA replication, is dynamically expressed in both proliferative and differentiated stromal cells during mouse periimplantation uterus. Applying PR-knockout mouse model and pharmacological strategy, we further found that the expression of Mcm2 is induced by progesterone action in the mouse uterine stroma. Employing a primary cell culture system, we further demonstrated that siRNA-mediated silencing of MCM2 arrests the cell cycle at G1-S transition during stromal cell proliferation. Moreover, the downregulation of Mcm2 could also compromise stromal cell differentiation. Collectively, our studies uncovered the role of a unique DNA replication licensing molecule MCM2 in mediating Progesterone-induced stromal cell decidualization in mouse uterus. PMID:26910396

  17. DNA From Dead Cancer Cells Induces TLR9-Mediated Invasion and Inflammation In Living Cancer Cells

    PubMed Central

    Tuomela, Johanna; Sandholm, Jouko; Kaakinen, Mika; Patel, Ankita; Kauppila, Joonas H.; Ilvesaro, Joanna; Chen, Dongquan; Harris, Kevin W.; Graves, David; Selander, Katri S.

    2014-01-01

    TLR9 is a cellular DNA-receptor, which is widely expressed in breast and other cancers. Although synthetic TLR9-ligands induce cancer cell invasion in vitro, the role of TLR9 in cancer pathophysiology has remained unclear. We show here that living cancer cells uptake DNA from chemotherapy-killed cancer cells. We discovered that such DNA induces TLR9- and cathepsin-mediated invasion in living cancer cells. To study whether this phenomenon contributes to treatment responses, triple negative, human MDA-MB-231 breast cancer cells stably expressing control or TLR9 siRNA were inoculated orthotopically into nude mice. The mice were treated with vehicle or doxorubicin. The tumor groups exhibited equal decreases in size in response to doxorubicin. However, while the weights of vehicle-treated mice were similar, mice bearing control siRNA tumors became significantly more cachectic in response to doxorubicin, as compared with similarly treated mice bearing TLR9 siRNA tumors, suggesting a TLR9-mediated inflammation at the site of the tumor. In conclusion, our findings propose that DNA released from chemotherapy-killed cancer cells has significant influence on TLR9-mediated biological effects in living cancer cells. Through these mechanisms, tumor TLR9 expression may affect treatment responses to chemotherapy. PMID:24212717

  18. Silver Nanoparticles Induce HePG-2 Cells Apoptosis Through ROS-Mediated Signaling Pathways

    NASA Astrophysics Data System (ADS)

    Zhu, Bing; Li, Yinghua; Lin, Zhengfang; Zhao, Mingqi; Xu, Tiantian; Wang, Changbing; Deng, Ning

    2016-04-01

    Recently, silver nanoparticles (AgNPs) have been shown to provide a novel approach to overcome tumors, especially those of hepatocarcinoma. However, the anticancer mechanism of silver nanoparticles is unclear. Thus, the purpose of this study was to estimate the effect of AgNPs on proliferation and activation of ROS-mediated signaling pathway on human hepatocellular carcinoma HePG-2 cells. A simple chemical method for preparing AgNPs with superior anticancer activity has been showed in this study. AgNPs were detected by transmission electronic microscopy (TEM) and energy dispersive X-ray (EDX). The size distribution and zeta potential of silver nanoparticles were detected by Zetasizer Nano. The average size of AgNPs (2 nm) observably increased the cellular uptake by endocytosis. AgNPs markedly inhibited the proliferation of HePG-2 cells through induction of apoptosis with caspase-3 activation and PARP cleavage. AgNPs with dose-dependent manner significantly increased the apoptotic cell population (sub-G1). Furthermore, AgNP-induced apoptosis was found dependent on the overproduction of reactive oxygen species (ROS) and affecting of MAPKs and AKT signaling and DNA damage-mediated p53 phosphorylation to advance HePG-2 cells apoptosis. Therefore, our results show that the mechanism of ROS-mediated signaling pathways may provide useful information in AgNP-induced HePG-2 cell apoptosis.

  19. The orphan nuclear receptor small heterodimer partner mediates male infertility induced by diethylstilbestrol in mice

    PubMed Central

    Volle, David H.; Decourteix, Mélanie; Garo, Erwan; McNeilly, Judy; Fenichel, Patrick; Auwerx, Johan; McNeilly, Alan S.; Schoonjans, Kristina; Benahmed, Mohamed

    2009-01-01

    Studies in rodents have shown that male sexual function can be disrupted by fetal or neonatal administration of compounds that alter endocrine homeostasis, such as the synthetic nonsteroidal estrogen diethylstilbestrol (DES). Although the molecular basis for this effect remains unknown, estrogen receptors likely play a critical role in mediating DES-induced infertility. Recently, we showed that the orphan nuclear receptor small heterodimer partner (Nr0b2), which is both a target gene and a transcriptional repressor of estrogen receptors, controls testicular function by regulating germ cell entry into meiosis and testosterone synthesis. We therefore hypothesized that some of the harmful effects of DES on testes could be mediated through Nr0b2. Here, we present data demonstrating that Nr0b2 deficiency protected mice against the negative effects of DES on testis development and function. During postnatal development, Nr0b2-null mice were resistant to DES-mediated inhibition of germ cell differentiation, which may be the result of interference by Nr0b2 with retinoid signals that control meiosis. Adult Nr0b2-null male mice were also protected against the effects of DES; however, we suggest that this phenomenon was due to the removal of the repressive effects of Nr0b2 on steroidogenesis. Together, these data demonstrate that Nr0b2 plays a critical role in the pathophysiological changes induced by DES in the mouse testis. PMID:19884658

  20. Cathepsin-B-mediated cleavage of Disabled-2 regulates TGF-β-induced autophagy.

    PubMed

    Jiang, Yong; Woosley, Alec N; Sivalingam, Nageswaran; Natarajan, Sneha; Howe, Philip H

    2016-08-01

    Transforming growth factor-β (TGF-β) induces the expression of Disabled-2 (Dab2), an endocytic adaptor and tumour suppressor, concomitant with the induction of an epithelial-mesenchymal transition (EMT) in mammary epithelial cells. Here we show that following TGF-β-mediated EMT, sustained TGF-β treatment leads to proteolytic degradation of Dab2 by cathepsin B (CTSB), loss of the mesenchymal phenotype and induction of autophagy. CTSB inhibition or expression of a CTSB-resistant Dab2 mutant maintains Dab2 expression and shifts long-term TGF-β-treated cells from autophagy to apoptosis. We further show that Dab2 interacts with Beclin-1 to promote casein-kinase-2-mediated phosphorylation of Beclin-1, preventing Beclin-1-Vps34 interaction and subsequent autophagosome assembly. Thus, CTSB-mediated degradation of Dab2 allows Beclin-1-Vps34 induction of autophagy, whereas sustained Dab2 expression prevents autophagy and promotes apoptosis by stabilizing the pro-apoptotic Bim protein. In vivo studies suggest that Dab2-mediated regulation of autophagy modulates chemotherapeutic resistance and tumour metastasis. PMID:27398911

  1. Apoptosis of THP-1 macrophages induced by protoporphyrin IX-mediated sonodynamic therapy

    PubMed Central

    Guo, Shuyuan; Sun, Xin; Cheng, Jiali; Xu, Haobo; Dan, Juhua; Shen, Jing; Zhou, Qi; Zhang, Yun; Meng, Lingli; Cao, Wenwu; Tian, Ye

    2013-01-01

    Background Sonodynamic therapy (SDT) was developed as a localized ultrasound-activated cytotoxic therapy for cancer. The ability of SDT to destroy target tissues selectively is especially appealing for atherosclerotic plaque, in which selective accumulation of the sonosensitizer, protoporphyrin IX (PpIX), had been demonstrated. Here we investigate the effects of PpIX-mediated SDT on macrophages, which are the main culprit in progression of atherosclerosis. Methods and results Cultured THP-1 derived macrophages were incubated with PpIX. Fluorescence microscopy showed that the intracellular PpIX concentration increased with the concentration of PpIX in the incubation medium. MTT assay demonstrated that SDT with PpIX significantly decreased cell viability, and this effect increased with duration of ultrasound exposure and PpIX concentration. PpIX-mediated SDT induced both apoptosis and necrosis, and the maximum apoptosis to necrosis ratio was obtained after SDT with 20 μg/mL PpIX and five minutes of sonication. Production of intracellular singlet oxygen and secondary disruption of the cytoskeleton were also observed after SDT with PpIX. Conclusion PpIX-mediated SDT had apoptotic effects on THP-1 macrophages via generation of intracellular singlet oxygen and disruption of the cytoskeleton. PpIX-mediated SDT may be a potential treatment to attenuate progression of atherosclerotic plaque. PMID:23818780

  2. Ret finger protein mediates Pax7-induced ubiquitination of MyoD in skeletal muscle atrophy.

    PubMed

    Joung, Hosouk; Eom, Gwang Hyeon; Choe, Nakwon; Lee, Hye Mi; Ko, Jeong-Hyeon; Kwon, Duk-Hwa; Nam, Yoon Seok; Min, Hyunki; Shin, Sera; Kook, Jeewon; Cho, Young Kuk; Kim, Jeong Chul; Seo, Sang Beom; Baik, Yung Hong; Nam, Kwang-Il; Kook, Hyun

    2014-10-01

    Skeletal muscle atrophy results from the net loss of muscular proteins and organelles and is caused by pathologic conditions such as nerve injury, immobilization, cancer, and other metabolic diseases. Recently, ubiquitination-mediated degradation of skeletal-muscle-specific transcription factors was shown to be involved in muscle atrophy, although the mechanisms have yet to be defined. Here we report that ret finger protein (RFP), also known as TRIM27, works as an E3 ligase in Pax7-induced degradation of MyoD. Muscle injury induced by sciatic nerve transection up-regulated RFP and RFP physically interacted with both Pax7 and MyoD. RFP and Pax7 synergistically reduced the protein amounts of MyoD but not the mRNA. RFP-induced reduction of MyoD protein was blocked by proteasome inhibitors. The Pax7-induced reduction MyoD was attenuated by RFP siRNA and by MG132, a proteasome inhibitor. RFPΔR, an RFP construct that lacks the RING domain, failed to reduce MyoD amounts. RFP ubiquitinated MyoD, but RFPΔR failed to do so. Forced expression of RFP, but not RFPΔR, enhanced Pax7-induced ubiquitination of MyoD, whereas RFP siRNA blocked the ubiquitination. Sciatic nerve injury-induced muscle atrophy as well the reduction in MyoD was attenuated in RFP knockout mice. Taken together, our results show that RFP works as a novel E3 ligase in the Pax7-mediated degradation of MyoD in response to skeletal muscle atrophy. PMID:25025573

  3. MCPIP1 mediates silica-induced cell migration in human pulmonary fibroblasts.

    PubMed

    Liu, Haijun; Dai, Xiaoniu; Cheng, Yusi; Fang, Shencun; Zhang, Yingming; Wang, Xingang; Zhang, Wei; Liao, Hong; Yao, Honghong; Chao, Jie

    2016-01-15

    Silicosis is a systemic disease caused by inhaling silicon dioxide (SiO2). Phagocytosis of SiO2 in the lungs initiates an inflammatory cascade that results in fibroblast proliferation and migration followed by fibrosis. According to previous data from our laboratory, monocyte chemotactic protein-1 (MCP-1) plays a critical role in fibroblast proliferation and migration in conventional two-dimensional (2D) monolayer cultures. The present study aimed to explore the downstream cascade of MCP-1 in both 2D and three-dimensional (3D) cell culture models of silicosis. Experiments using primary cultured adult human pulmonary fibroblasts (HPF-a) demonstrated the following: 1) SiO2 treatment induces expression of MCP-1-induced protein (MCPIP1) in a time- and dose-dependent manner in both 2D and 3D cultures; 2) the MAPK and phosphatidylinositol-3-kinase (PI3K)/Akt pathways are involved in SiO2-induced MCPIP1 expression; and 3) MCPIP1 induction mediates the SiO2-induced increase in cell migration in both 2D and 3D cultures. The effect of MCP-1 in silicosis occurs mainly through MCPIP1, which, in turn, mediates the observed SiO2-induced increase in pulmonary fibroblast migration. However, the time frame for MCPIP1 induction differed between 2D and 3D cultures, indicating that, compared with conventional 2D cell culture systems, 3D culture may be useful for analyses of fibroblast physiology under conditions that more closely resemble in vivo environments. Our study determined the link between fibroblast-derived MCPIP1 and SiO2-induced cell migration, and this finding provides novel evidence of the potential of MCPIP1 in the development of novel therapeutic strategies for silicosis. PMID:26608530

  4. Marijuana smoke condensate induces p53-mediated apoptosis in human lung epithelial cells.

    PubMed

    Kim, Ha Ryong; Jung, Mi Hyun; Lee, Soo Yeun; Oh, Seung Min; Chung, Kyu Hyuck

    2013-01-01

    Since the largely abused worldwide used of marijuana, there have been many ongoing debates regarding the adverse health effects of marijuana smoking. Marijuana smoking was recently proved to cause pulmonary toxicity by inducing genotoxic effects or generating reactive oxygen species. Because p53, a tumor suppressor gene, has an important pathophysiologic role in the regulation of lung epithelial cell DNA damage responses, we hypothesized that p53 may be involved in the oxidative stress-mediated apoptosis induced by marijuana smoking. First, we confirmed that marijuana smoke condensate (MSC) induces oxidative stress in BEAS-2B cells. We observed that reactive oxygen species (ROS) generation was increased by MSC in the DCFH-DA assay. Also, antioxidant enzyme (superoxide dismutase, catalase) activity and their mRNA expressions were up-regulated by MSC. Second, we investigated p53 involvement in the MSC-induced apoptotic pathway in BEAS-2B cells. The results showed that MSC increased caspase-3 activation and DNA fragmentation as markers of apoptosis. In addition, the mRNA levels of apoptosis-related genes (p53 and Bax) were increased by MSC and phospho-p53, along with the increase of Bax protein expression by MSC. Apoptosis and apoptosis-related gene expression were partially blocked by an inhibitor of p53-dependent transcriptional activation (pifithrin-α). The results indicate that p53 plays a role in MSC-induced apoptosis. Taken together, the findings of the present study suggest that MSC partially induces p53-mediated apoptosis through ROS generation in human lung epithelial cells and this may have broader implications for our understanding of pulmonary diseases. PMID:23665932

  5. SOD2-mediated Adaptive Responses Induced by Low Dose Ionizing Radiation via TNF Signaling and Amifostine

    PubMed Central

    Murley, J.S.; Baker, K.L.; Miller, R.C.; Darga, T.E.; Weichselbaum, R.R.; Grdina, D.J.

    2011-01-01

    Manganese superoxide dismutase (SOD2)-mediated adaptive processes that protect against radiation-induced micronuclei formation can be induced in cells following a 2 Gy exposure by previously exposing them to either low dose ionizing radiation (10 cGy) or WR1065 (40 µM), the active thiol form of amifostine. While both adaptive processes culminate with elevated levels of SOD2 enzymatic activities, the underlying pathways differ in complexity, with the tumor necrosis factor α (TNFα) signaling pathway implicated in the low dose radiation-induced response, but not in the thiol-induced pathway. The goal of this study was the characterization of the effects of TNFα receptors1 and 2 (TNFR1, 2) on the adaptive responses induced by low dose irradiation or thiol exposures using micronuclei formation as an endpoint. BFS-1 wild type (WT) cells with functional TNFR1 and 2 were exposed 24 h prior to a 2 Gy dose of ionizing radiation to either 10 cGy or a 40 µM dose of WR1065. BFS2C-SH02 cells defective in TNFR1 and BFS2C-SH22 cells defective in both TNFR1 and 2, generated from BFS2C-SH02 cells by transfection with a murine TNFR2 targeting vector and confirmed to be TNFR2 defective by quantitative PCR, were also exposed under similar conditions for comparison. A 10 cGy dose of radiation induced a significant elevation of SOD2 activity in BFS-1 (P < 0.001) and BFS2C-SH02 (P = 0.005) but not BFS2C-SH22 cells (P = 0.433) as compared to their respective untreated controls. In contrast, WR1065 significantly induced elevations in SOD2 activity in all three cell lines (P = 0.001; P = 0.007; P = 0.020; respectively). A significant reduction in the frequency of radiation-induced micronuclei was observed in each cell line when exposure to a 2 Gy challenge dose of radiation occurred during the period of maximal elevation in SOD2 activity. However, this adaptive effect was completely inhibited if the cells were transfected 24 h prior to low dose radiation or thiol exposure with SOD2 si

  6. Hydrogen sulfide mitigates homocysteine mediated pathological remodeling by inducing miR-133a in cardiomyocytes

    PubMed Central

    Kesherwani, Varun; Nandi, Shyam S.; Sharawat, Surender K.; Shahshahan, Hamid R.; Mishra, Paras K.

    2015-01-01

    An elevated level of homocysteine called hyperhomocysteinemia (HHcy) is associated with pathological cardiac remodeling. Hydrogen sulfide (H2S) acts as a cardioprotective gas, however the mechanism by which H2S mitigates homocysteine mediated pathological remodeling in cardiomyocytes is unclear. We hypothesized that H2S ameliorates HHcy mediated hypertrophy by inducing cardioprotective miR-133a in cardiomyocytes. To test the hypothesis, HL1 cardiomyocytes were treated with: 1) plain medium (control, CT), 2) 100μM of homocysteine (Hcy), 3) Hcy with 30μM of H2S (Hcy+H2S), and 4) H2S for 24 hour. The levels of hypertrophy markers: c-fos, atrial natriuretic peptide (ANP), and beta-myosin heavy chain (β-MHC), miR-133a and its transcriptional inducer myosin enhancer factor- 2c (MEF2C) were determined by Western blotting, RT-qPCR, and immunofluorescence. The activity of MEF2C was assessed by co-immunoprecipitation of MEF2C with histone deacetylase -1(HDAC1). Our results show that H2S ameliorates homocysteine mediated up regulation of c-fos, ANP and β-MHC, and down regulation of MEF2C and miR-133a. HHcy induces the binding of MEF2C with HDAC1, whereas H2S releases MEF2C from MEF2C-HDAC1 complex causing activation of MEF2C. These findings elicit that HHcy induces cardiac hypertrophy by promoting MEF2C-HDAC1 complex formation that inactivates MEF2C causing suppression of anti-hypertrophy miR-133a in cardiomyocytes. H2S mitigates hypertrophy by inducing miR-133a through activation of MEF2C in HHcy cardiomyocytes. To our knowledge this is a novel mechanism of H2S mediated activation of MEF2C and induction of miR-133a and inhibition of hypertrophy in HHcy cardiomyocytes. PMID:25763715

  7. Nitric-oxide-induced necrosis and apoptosis in PC12 cells mediated by mitochondria.

    PubMed

    Bal-Price, A; Brown, G C

    2000-10-01

    Nitric oxide (NO) can trigger either necrotic or apoptotic cell death. We have used PC12 cells to investigate the extent to which NO-induced cell death is mediated by mitochondria. Addition of NO donors, 1 mM S-nitroso-N-acetyl-DL-penicillamine (SNAP) or 1 mM diethylenetriamine-NO adduct (NOC-18), to PC12 cells resulted in a steady-state level of 1-3 microM: NO, rapid and almost complete inhibition of cellular respiration (within 1 min), and a rapid decrease in mitochondrial membrane potential within the cells. A 24-h incubation of PC12 cells with NO donors (SNAP or NOC-18) or specific inhibitors of mitochondrial respiration (myxothiazol, rotenone, or azide), in the absence of glucose, caused total ATP depletion and resulted in 80-100% necrosis. The presence of glucose almost completely prevented the decrease in ATP level and the increase in necrosis induced by the NO donors or mitochondrial inhibitors, suggesting that the NO-induced necrosis in the absence of glucose was due to the inhibition of mitochondrial respiration and subsequent ATP depletion. However, in the presence of glucose, NO donors and mitochondrial inhibitors induced apoptosis of PC12 cells as determined by nuclear morphology. The presence of apoptotic cells was prevented completely by benzyloxycarbonyl-Val-Ala-fluoromethyl ketone (a nonspecific caspase inhibitor), indicating that apoptosis was mediated by caspase activation. Indeed, both NO donors and mitochondrial inhibitors in PC12 cells caused the activation of caspase-3- and caspase-3-processing-like proteases. Caspase-1 activity was not activated. Cyclosporin A (an inhibitor of the mitochondrial permeability transition pore) decreased the activity of caspase-3- and caspase-3-processing-like proteases after treatment with NO donors, but was not effective in the case of the mitochondrial inhibitors. The activation of caspases was accompanied by the release of cytochrome c from mitochondria into the cytosol, which was partially prevented by

  8. Proinflammatory caspase-2-mediated macrophage cell death induced by a rough attenuated Brucella suis strain.

    PubMed

    Chen, Fang; Ding, Xicheng; Ding, Ying; Xiang, Zuoshuang; Li, Xinna; Ghosh, Debashis; Schurig, Gerhardt G; Sriranganathan, Nammalwar; Boyle, Stephen M; He, Yongqun

    2011-06-01

    Brucella spp. are intracellular bacteria that cause an infectious disease called brucellosis in humans and many domestic and wildlife animals. B. suis primarily infects pigs and is pathogenic to humans. The macrophage-Brucella interaction is critical for the establishment of a chronic Brucella infection. Our studies showed that smooth virulent B. suis strain 1330 (S1330) prevented programmed cell death of infected macrophages and rough attenuated B. suis strain VTRS1 (a vaccine candidate) induced strong macrophage cell death. To further investigate the mechanism of VTRS1-induced macrophage cell death, microarrays were used to analyze temporal transcriptional responses of murine macrophage-like J774.A1 cells infected with S1330 or VTRS1. In total 17,685 probe sets were significantly regulated based on the effects of strain, time and their interactions. A miniTUBA dynamic Bayesian network analysis predicted that VTRS1-induced macrophage cell death was mediated by a proinflammatory gene (the tumor necrosis factor alpha [TNF-α] gene), an NF-κB pathway gene (the IκB-α gene), the caspase-2 gene, and several other genes. VTRS1 induced significantly higher levels of transcription of 40 proinflammatory genes than S1330. A Mann-Whitney U test confirmed the proinflammatory response in VTRS1-infected macrophages. Increased production of TNF-α and interleukin 1β (IL-1β) were also detected in the supernatants in VTRS1-infected macrophage cell culture. Hyperphosphorylation of IκB-α was observed in macrophages infected with VTRS1 but not S1330. The important roles of TNF-α and IκB-α in VTRS1-induced macrophage cell death were further confirmed by individual inhibition studies. VTRS1-induced macrophage cell death was significantly inhibited by a caspase-2 inhibitor but not a caspase-1 inhibitor. The role of caspase-2 in regulating the programmed cell death of VTRS1-infected macrophages was confirmed in another study using caspase-2-knockout mice. In summary, VTRS1

  9. Loss of serum response factor induces microRNA-mediated apoptosis in intestinal smooth muscle cells

    PubMed Central

    Park, C; Lee, M Y; Slivano, O J; Park, P J; Ha, S; Berent, R M; Fuchs, R; Collins, N C; Yu, T J; Syn, H; Park, J K; Horiguchi, K; Miano, J M; Sanders, K M; Ro, S

    2015-01-01

    Serum response factor (SRF) is a transcription factor known to mediate phenotypic plasticity in smooth muscle cells (SMCs). Despite the critical role of this protein in mediating intestinal injury response, little is known about the mechanism through which SRF alters SMC behavior. Here, we provide compelling evidence for the involvement of SRF-dependent microRNAs (miRNAs) in the regulation of SMC apoptosis. We generated SMC-restricted Srf inducible knockout (KO) mice and observed both severe degeneration of SMCs and a significant decrease in the expression of apoptosis-associated miRNAs. The absence of these miRNAs was associated with overexpression of apoptotic proteins, and we observed a high level of SMC death and myopathy in the intestinal muscle layers. These data provide a compelling new model that implicates SMC degeneration via anti-apoptotic miRNA deficiency caused by lack of SRF in gastrointestinal motility disorders. PMID:26633717

  10. Diet-induced obesity mediated by the JNK/DIO2 signal transduction pathway

    PubMed Central

    Vernia, Santiago; Cavanagh-Kyros, Julie; Barrett, Tamera; Jung, Dae Young; Kim, Jason K.; Davis, Roger J.

    2013-01-01

    The cJun N-terminal kinase (JNK) signaling pathway is a key mediator of metabolic stress responses caused by consuming a high-fat diet, including the development of obesity. To test the role of JNK, we examined diet-induced obesity in mice with targeted ablation of Jnk genes in the anterior pituitary gland. These mice exhibited an increase in the pituitary expression of thyroid-stimulating hormone (TSH), an increase in the blood concentration of thyroid hormone (T4), increased energy expenditure, and markedly reduced obesity compared with control mice. The increased amount of pituitary TSH was caused by reduced expression of type 2 iodothyronine deiodinase (Dio2), a gene that is required for T4-mediated negative feedback regulation of TSH expression. These data establish a molecular mechanism that accounts for the regulation of energy expenditure and the development of obesity by the JNK signaling pathway. PMID:24186979

  11. Hypoxia-inducible factors: mediators of cancer progression and targets for cancer therapy

    PubMed Central

    Semenza, Gregg L.

    2012-01-01

    Hypoxia-inducible factors (HIFs) mediate adaptive physiological responses to hypoxia. In human cancers that are accessible for O2 electrode measurements, intratumoral hypoxia is common and is associated with increased risk of mortality. HIF activity in regions of intratumoral hypoxia mediates angiogenesis, epithelial-mesenchymal transition, stem cell maintenance, invasion, metastasis, and resistance to radiation therapy and chemotherapy. A growing number of drugs have been identified that inhibit HIF activity by a variety of molecular mechanisms. Because many of these drugs are already FDA-approved for other indications, clinical trials can (and should) be initiated to test the hypothesis that incorporation of HIF inhibitors into current standard-of-care therapy will increase the survival of cancer patients. PMID:22398146

  12. Heat shock protein-mediated protection against Cisplatin-induced hair cell death.

    PubMed

    Baker, Tiffany G; Roy, Soumen; Brandon, Carlene S; Kramarenko, Inga K; Francis, Shimon P; Taleb, Mona; Marshall, Keely M; Schwendener, Reto; Lee, Fu-Shing; Cunningham, Lisa L

    2015-02-01

    Cisplatin is a highly successful and widely used chemotherapy for the treatment of various solid malignancies in both adult and pediatric patients. Side effects of cisplatin treatment include nephrotoxicity and ototoxicity. Cisplatin ototoxicity results from damage to and death of cells in the inner ear, including sensory hair cells. We showed previously that heat shock inhibits cisplatin-induced hair cell death in whole-organ cultures of utricles from adult mice. Since heat shock protein 70 (HSP70) is the most upregulated HSP in response to heat shock, we investigated the role of HSP70 as a potential protectant against cisplatin-induced hair cell death. Our data using utricles from HSP70 (-/-) mice indicate that HSP70 is necessary for the protective effect of heat shock against cisplatin-induced hair cell death. In addition, constitutive expression of inducible HSP70 offered modest protection against cisplatin-induced hair cell death. We also examined a second heat-inducible protein, heme oxygenase-1 (HO-1, also called HSP32). HO-1 is an enzyme responsible for the catabolism of free heme. We previously showed that induction of HO-1 using cobalt protoporphyrin IX (CoPPIX) inhibits aminoglycoside-induced hair cell death. Here, we show that HO-1 also offers significant protection against cisplatin-induced hair cell death. HO-1 induction occurred primarily in resident macrophages, with no detectable expression in hair cells or supporting cells. Depletion of macrophages from utricles abolished the protective effect of HO-1 induction. Together, our data indicate that HSP induction protects against cisplatin-induced hair cell death, and they suggest that resident macrophages mediate the protective effect of HO-1 induction. PMID:25261194

  13. The obesity-induced transcriptional regulator TRIP-Br2 mediates visceral fat endoplasmic reticulum stress-induced inflammation

    PubMed Central

    Qiang, Guifen; Kong, Hyerim Whang; Fang, Difeng; McCann, Maximilian; Yang, Xiuying; Du, Guanhua; Blüher, Matthias; Zhu, Jinfang; Liew, Chong Wee

    2016-01-01

    The intimate link between location of fat accumulation and metabolic disease risk and depot-specific differences is well established, but how these differences between depots are regulated at the molecular level remains largely unclear. Here we show that TRIP-Br2 mediates endoplasmic reticulum (ER) stress-induced inflammatory responses in visceral fat. Using in vitro, ex vivo and in vivo approaches, we demonstrate that obesity-induced circulating factors upregulate TRIP-Br2 specifically in visceral fat via the ER stress pathway. We find that ablation of TRIP-Br2 ameliorates both chemical and physiological ER stress-induced inflammatory and acute phase response in adipocytes, leading to lower circulating levels of inflammatory cytokines. Using promoter assays, as well as molecular and pharmacological experiments, we show that the transcription factor GATA3 is responsible for the ER stress-induced TRIP-Br2 expression in visceral fat. Taken together, our study identifies molecular regulators of inflammatory response in visceral fat that—given that these pathways are conserved in humans—might serve as potential therapeutic targets in obesity. PMID:27109496

  14. The obesity-induced transcriptional regulator TRIP-Br2 mediates visceral fat endoplasmic reticulum stress-induced inflammation.

    PubMed

    Qiang, Guifen; Kong, Hyerim Whang; Fang, Difeng; McCann, Maximilian; Yang, Xiuying; Du, Guanhua; Blüher, Matthias; Zhu, Jinfang; Liew, Chong Wee

    2016-01-01

    The intimate link between location of fat accumulation and metabolic disease risk and depot-specific differences is well established, but how these differences between depots are regulated at the molecular level remains largely unclear. Here we show that TRIP-Br2 mediates endoplasmic reticulum (ER) stress-induced inflammatory responses in visceral fat. Using in vitro, ex vivo and in vivo approaches, we demonstrate that obesity-induced circulating factors upregulate TRIP-Br2 specifically in visceral fat via the ER stress pathway. We find that ablation of TRIP-Br2 ameliorates both chemical and physiological ER stress-induced inflammatory and acute phase response in adipocytes, leading to lower circulating levels of inflammatory cytokines. Using promoter assays, as well as molecular and pharmacological experiments, we show that the transcription factor GATA3 is responsible for the ER stress-induced TRIP-Br2 expression in visceral fat. Taken together, our study identifies molecular regulators of inflammatory response in visceral fat that-given that these pathways are conserved in humans-might serve as potential therapeutic targets in obesity. PMID:27109496

  15. Protein Phosphatase 2A Mediates Oxidative Stress Induced Apoptosis in Osteoblasts.

    PubMed

    Huang, Chong-xin; Lv, Bo; Wang, Yue

    2015-01-01

    Osteoporosis is one of the most common bone diseases, which is characterized by a systemic impairment of bone mass and fragility fractures. Age-related oxidative stress is highly associated with impaired osteoblastic dysfunctions and subsequent osteoporosis. In osteoblasts (bone formation cells), reactive oxygen species (ROS) are continuously generated and further cause lipid peroxidation, protein damage, and DNA lesions, leading to osteoblastic dysfunctions, dysdifferentiations, and apoptosis. Although much progress has been made, the mechanism responsible for oxidative stress induced cellular alternations and osteoblastic toxicity is still not fully elucidated. Here, we demonstrate that protein phosphatase 2A (PP2A), a major protein phosphatase in mammalian cells, mediates oxidative stress induced apoptosis in osteoblasts. Our results showed that lipid peroxidation products (4-HNE) may induce dramatic oxidative stress, inflammatory reactions, and apoptosis in osteoblasts. These oxidative stress responses may ectopically activate PP2A phosphatase activity, which may be mediated by inactivation of AKT/mTOR pathway. Moreover, inhibition of PP2A activity by okadaic acid might partly prevent osteoblastic apoptosis under oxidative conditions. These findings may reveal a novel mechanism to clarify the role of oxidative stress for osteoblastic apoptosis and provide new possibilities for the treatment of related bone diseases, such as osteoporosis. PMID:26538836

  16. Maternal immunity enhances Mycoplasma hyopneumoniae vaccination induced cell-mediated immune responses in piglets

    PubMed Central

    2014-01-01

    Background Passively acquired maternal derived immunity (MDI) is a double-edged sword. Maternal derived antibody-mediated immunity (AMI) and cell-mediated immunity (CMI) are critical immediate defenses for the neonate; however, MDI may interfere with the induction of active immunity in the neonate, i.e. passive interference. The effect of antigen-specific MDI on vaccine-induced AMI and CMI responses to Mycoplasma hyopneumoniae (M. hyopneumoniae) was assessed in neonatal piglets. To determine whether CMI and AMI responses could be induced in piglets with MDI, piglets with high and low levels of maternal M. hyopneumoniae-specific immunity were vaccinated against M. hyopneumoniae at 7 d of age. Piglet M. hyopneumoniae-specific antibody, lymphoproliferation, and delayed type hypersensitivity (DTH) responses were measured 7 d and 14 d post vaccination. Results Piglets with M. hyopneumoniae-specific MDI failed to show vaccine-induced AMI responses; there was no rise in M. hyopneumoniae antibody levels following vaccination of piglets in the presence of M. hyopneumoniae-specific MDI. However, piglets with M. hyopneumoniae-specific MDI had primary (antigen-specific lymphoproliferation) and secondary (DTH) M. hyopneumoniae-specific CMI responses following vaccination. Conclusions In this study neonatal M. hyopneumoniae-specific CMI was not subject to passive interference by MDI. Further, it appears that both maternal derived and endogenous CMI contribute to M. hyopneumoniae-specific CMI responses in piglets vaccinated in the face of MDI. PMID:24903770

  17. Nature and action of the mediators inducing maturation of the starfish oocyte.

    PubMed

    Kanatani, H

    1983-01-01

    The process of oocyte maturation and ovulation in starfish is triggered by a gonad-stimulating substance (GSS) present in the granules contained in the supporting cells of the nervous system. The GSS of Asterias amurensis is a polypeptide with a relative molecular mass (Mr) of about 2100, consisting of 22 amino acid residues. This peptide hormone is secreted from the nervous system and acts on the follicular cells around the oocyte to stimulate the production of the second mediator, maturation-inducing substance (MIS). MIS has been identified as 1-methyladenine. 1-Methyladenine acts on the surface of the oocyte, probably on the oocyte-surface factor, to induce the production of a cytoplasmic factor called maturation-promoting factor (MPF) in the ooplasm. This third mediator induces germinal vesicle breakdown and the subsequent processes of oocyte maturation up to the formation of the female pronucleus. MPF appears to be a phosphoprotein and is known in other animals. MPF obtained from any source appears to bring about nuclear membrane breakdown in both meiosis and mitosis, and the nature of MPF is very similar in vertebrates and invertebrates. PMID:6357668

  18. 4-Hydroxynonenal induces p53-mediated apoptosis in retinal pigment epithelial cells

    PubMed Central

    Sharma, Abha; Sharma, Rajendra; Chaudhary, Pankaj; Vatsyayan, Rit; Pearce, Virginia; Jeyabal, Prince V.S.; Zimniak, Piotr; Awasthi, Sanjay; Awasthi, Yogesh C.

    2009-01-01

    4-Hydroxynonenal (4-HNE) has been suggested to be involved in stress-induced signaling for apoptosis. In present studies, we have examined the effects of 4-HNE on the intrinsic apoptotic pathway associated with p53 in human retinal pigment epithelial (RPE and ARPE-19) cells. Our results show that 4-HNE causes induction, phosphorylation, and nuclear accumulation of p53 which is accompanied with down regulation of MDM2, activation of the pro-apoptotic p53 target genes viz. p21 and Bax, JNK, caspase3, and onset of apoptosis in treated RPE cells. Reduced expression of p53 by an efficient silencing of the p53 gene resulted in a significant resistance of these cells to 4-HNE-induced cell death. The effects of 4-HNE on the expression and functions of p53 are blocked in GSTA4-4 over expressing cells indicating that 4-HNE-induced, p53-mediated signaling for apoptosis is regulated by GSTs. Our results also show that the induction of p53 in tissues of mGsta4 (-/-) mice correlate with elevated levels of 4-HNE due to its impaired metabolism. Together, these studies suggest that 4-HNE is involved in p53-mediated signaling in in vitro cell cultures as well as in vivo that can be regulated by GSTs. PMID:18930016

  19. Autocrine fibroblast growth factor 18 mediates dexamethasone-induced osteogenic differentiation of murine mesenchymal stem cells.

    PubMed

    Hamidouche, Zahia; Fromigué, Olivia; Nuber, Ulrike; Vaudin, Pascal; Pages, Jean-Christophe; Ebert, Regina; Jakob, Franz; Miraoui, Hichem; Marie, Pierre J

    2010-08-01

    The potential of mesenchymal stem cells (MSC) to differentiate into functional bone forming cells provides an important tool for bone regeneration. The identification of factors capable of promoting osteoblast differentiation in MSCs is therefore critical to enhance the osteogenic potential of MSCs. Using microarray analysis combined with biochemical and molecular approach, we found that FGF18, a member of the FGF family, is upregulated during osteoblast differentiation induced by dexamethasone in murine MSCs. We showed that overexpression of FGF18 by lentiviral (LV) infection, or treatment of MSCs with recombinant human (rh)FGF18 increased the expression of the osteoblast specific transcription factor Runx2, and enhanced osteoblast phenotypic marker gene expression and in vitro osteogenesis. Molecular silencing using lentiviral shRNA demonstrated that downregulation of FGFR1 or FGFR2 abrogated osteoblast gene expression induced by either LV-FGF18 or rhFGF18, indicating that FGF18 enhances osteoblast differentiation in MSCs via activation of FGFR1 or FGFR2 signaling. Biochemical and pharmacological analyses showed that the induction of phenotypic osteoblast markers by LV-FGF18 is mediated by activation of ERK1/2-MAPKs and PI3K signaling in MSCs. These results reveal that FGF18 is an essential autocrine positive regulator of the osteogenic differentiation program in murine MSCs and indicate that osteogenic differentiation induced by FGF18 in MSCs is triggered by FGFR1/FGFR2-mediated ERK1/2-MAPKs and PI3K signaling. PMID:20432451

  20. Protein Phosphatase 2A Mediates Oxidative Stress Induced Apoptosis in Osteoblasts

    PubMed Central

    Huang, Chong-xin; Lv, Bo; Wang, Yue

    2015-01-01

    Osteoporosis is one of the most common bone diseases, which is characterized by a systemic impairment of bone mass and fragility fractures. Age-related oxidative stress is highly associated with impaired osteoblastic dysfunctions and subsequent osteoporosis. In osteoblasts (bone formation cells), reactive oxygen species (ROS) are continuously generated and further cause lipid peroxidation, protein damage, and DNA lesions, leading to osteoblastic dysfunctions, dysdifferentiations, and apoptosis. Although much progress has been made, the mechanism responsible for oxidative stress induced cellular alternations and osteoblastic toxicity is still not fully elucidated. Here, we demonstrate that protein phosphatase 2A (PP2A), a major protein phosphatase in mammalian cells, mediates oxidative stress induced apoptosis in osteoblasts. Our results showed that lipid peroxidation products (4-HNE) may induce dramatic oxidative stress, inflammatory reactions, and apoptosis in osteoblasts. These oxidative stress responses may ectopically activate PP2A phosphatase activity, which may be mediated by inactivation of AKT/mTOR pathway. Moreover, inhibition of PP2A activity by okadaic acid might partly prevent osteoblastic apoptosis under oxidative conditions. These findings may reveal a novel mechanism to clarify the role of oxidative stress for osteoblastic apoptosis and provide new possibilities for the treatment of related bone diseases, such as osteoporosis. PMID:26538836

  1. The endocannabinoid system mediates aerobic exercise-induced antinociception in rats.

    PubMed

    Galdino, Giovane; Romero, Thiago R L; Silva, José Felipe P; Aguiar, Daniele C; de Paula, Ana Maria; Cruz, Jader S; Parrella, Cosimo; Piscitelli, Fabiana; Duarte, Igor D; Di Marzo, Vincenzo; Perez, Andrea C

    2014-02-01

    Exercise-induced antinociception is widely described in the literature, but the mechanisms involved in this phenomenon are poorly understood. Systemic (s.c.) and central (i.t., i.c.v.) pretreatment with CB₁ and CB₂ cannabinoid receptor antagonists (AM251 and AM630) blocked the antinociception induced by an aerobic exercise (AE) protocol in both mechanical and thermal nociceptive tests. Western blot analysis revealed an increase and activation of CB₁ receptors in the rat brain, and immunofluorescence analysis demonstrated an increase of activation and expression of CB₁ receptors in neurons of the periaqueductal gray matter (PAG) after exercise. Additionally, pretreatment (s.c., i.t. and i.c.v.) with endocannabinoid metabolizing enzyme inhibitors (MAFP and JZL184) and an anandamide reuptake inhibitor (VDM11) prolonged and intensified this antinociceptive effect. These results indicate that exercise could activate the endocannabinoid system, producing antinociception. Supporting this hypothesis, liquid-chromatography/mass-spectrometry measurements demonstrated that plasma levels of endocannabinoids (anandamide and 2-arachidonoylglycerol) and of anandamide-related mediators (palmitoylethanolamide and oleoylethanolamide) were increased after AE. Therefore, these results suggest that the endocannabinoid system mediates aerobic exercise-induced antinociception at peripheral and central levels. PMID:24148812

  2. A novel fur- and iron-regulated small RNA, NrrF, is required for indirect fur-mediated regulation of the sdhA and sdhC genes in Neisseria meningitidis.

    PubMed

    Mellin, J R; Goswami, Sulip; Grogan, Susan; Tjaden, Brian; Genco, Caroline A

    2007-05-01

    Iron is both essential for bacterial growth and toxic at higher concentrations; thus, iron homeostasis is tightly regulated. In Neisseria meningitidis the majority of iron-responsive gene regulation is mediated by the ferric uptake regulator protein (Fur), a protein classically defined as a transcriptional repressor. Recently, however, microarray studies have identified a number of genes in N. meningitidis that are iron and Fur activated, demonstrating a new role for Fur as a transcriptional activator. Since Fur has been shown to indirectly activate gene transcription through the repression of small regulatory RNA molecules in other organisms, we hypothesized that a similar mechanism could account for Fur-dependent, iron-activated gene transcription in N. meningitidis. In this study, we used a bioinformatics approach to screen for the presence of Fur-regulated small RNA molecules in N. meningitidis MC58. This screen identified one small RNA, herein named NrrF (for neisserial regulatory RNA responsive to iron [Fe]), which was demonstrated to be both iron responsive and Fur regulated and which has a well-conserved orthologue in N. gonorrhoeae. In addition, this screen identified a number of other likely, novel small RNA transcripts. Lastly, we utilized a new bioinformatics approach to predict regulatory targets of the NrrF small RNA. This analysis led to the identification of the sdhA and sdhC genes, which were subsequently demonstrated to be under NrrF regulation in an nrrF mutant. This study is the first report of small RNAs in N. meningitidis and the first to use a bioinformatics approach to identify, a priori, regulatory targets of a small RNA. PMID:17351036

  3. A Novel Fur- and Iron-Regulated Small RNA, NrrF, Is Required for Indirect Fur-Mediated Regulation of the sdhA and sdhC Genes in Neisseria meningitidis▿ †

    PubMed Central

    Mellin, J. R.; Goswami, Sulip; Grogan, Susan; Tjaden, Brian; Genco, Caroline A.

    2007-01-01

    Iron is both essential for bacterial growth and toxic at higher concentrations; thus, iron homeostasis is tightly regulated. In Neisseria meningitidis the majority of iron-responsive gene regulation is mediated by the ferric uptake regulator protein (Fur), a protein classically defined as a transcriptional repressor. Recently, however, microarray studies have identified a number of genes in N. meningitidis that are iron and Fur activated, demonstrating a new role for Fur as a transcriptional activator. Since Fur has been shown to indirectly activate gene transcription through the repression of small regulatory RNA molecules in other organisms, we hypothesized that a similar mechanism could account for Fur-dependent, iron-activated gene transcription in N. meningitidis. In this study, we used a bioinformatics approach to screen for the presence of Fur-regulated small RNA molecules in N. meningitidis MC58. This screen identified one small RNA, herein named NrrF (for neisserial regulatory RNA responsive to iron [Fe]), which was demonstrated to be both iron responsive and Fur regulated and which has a well-conserved orthologue in N. gonorrhoeae. In addition, this screen identified a number of other likely, novel small RNA transcripts. Lastly, we utilized a new bioinformatics approach to predict regulatory targets of the NrrF small RNA. This analysis led to the identification of the sdhA and sdhC genes, which were subsequently demonstrated to be under NrrF regulation in an nrrF mutant. This study is the first report of small RNAs in N. meningitidis and the first to use a bioinformatics approach to identify, a priori, regulatory targets of a small RNA. PMID:17351036

  4. The agricultural antibiotic carbadox induces phage-mediated gene transfer in Salmonella

    PubMed Central

    Bearson, Bradley L.; Allen, Heather K.; Brunelle, Brian W.; Lee, In Soo; Casjens, Sherwood R.; Stanton, Thaddeus B.

    2013-01-01

    Antibiotics are used for disease therapeutic or preventative effects in humans and animals, as well as for enhanced feed conversion efficiency in livestock. Antibiotics can also cause undesirable effects in microbial populations, including selection for antibiotic resistance, enhanced pathogen invasion, and stimulation of horizontal gene transfer. Carbadox is a veterinary antibiotic used in the US during the starter phase of swine production for improved feed efficiency and control of swine dysentery and bacterial swine enteritis. Carbadox has been shown in vitro to induce phage-encoded Shiga toxin in Shiga toxin-producing Escherichia coli (STEC) and a phage-like element transferring antibiotic resistance genes in Brachyspira hyodysenteriae, but the effect of carbadox on prophages in other bacteria is unknown. This study examined carbadox exposure on prophage induction and genetic transfer in Salmonella enterica serovar Typhimurium, a human foodborne pathogen that frequently colonizes swine without causing disease. S. Typhimurium LT2 exposed to carbadox induced prophage production, resulting in bacterial cell lysis and release of virions that were visible by electron microscopy. Carbadox induction of phage-mediated gene transfer was confirmed by monitoring the transduction of a sodCIII::neo cassette in the Fels-1 prophage from LT2 to a recipient Salmonella strain. Furthermore, carbadox frequently induced generalized transducing phages in multidrug-resistant phage type DT104 and DT120 isolates, resulting in the transfer of chromosomal and plasmid DNA that included antibiotic resistance genes. Our research indicates that exposure of Salmonella to carbadox induces prophages that can transfer virulence and antibiotic resistance genes to susceptible bacterial hosts. Carbadox-induced, phage-mediated gene transfer could serve as a contributing factor in bacterial evolution during animal production, with prophages being a reservoir for bacterial fitness genes in the

  5. Proinflammatory adipokine leptin mediates disinfection byproduct bromodichloromethane-induced early steatohepatitic injury in obesity

    SciTech Connect

    Das, Suvarthi; Kumar, Ashutosh; Seth, Ratanesh Kumar; Tokar, Erik J.; Kadiiska, Maria B.; Waalkes, Michael P.; Mason, Ronald P.; Chatterjee, Saurabh

    2013-06-15

    Today's developed world faces a major public health challenge in the rise in the obese population and the increased incidence in fatty liver disease. There is a strong association among diet induced obesity, fatty liver disease and development of nonalcoholic steatohepatitis but the environmental link to disease progression remains unclear. Here we demonstrate that in obesity, early steatohepatitic lesions induced by the water disinfection byproduct bromodichloromethane are mediated by increased oxidative stress and leptin which act in synchrony to potentiate disease progression. Low acute exposure to bromodichloromethane (BDCM), in diet-induced obesity produced oxidative stress as shown by increased lipid peroxidation, protein free radical and nitrotyrosine formation and elevated leptin levels. Exposed obese mice showed histopathological signs of early steatohepatitic injury and necrosis. Spontaneous knockout mice for leptin or systemic leptin receptor knockout mice had significantly decreased oxidative stress and TNF-α levels. Co-incubation of leptin and BDCM caused Kupffer cell activation as shown by increased MCP-1 release and NADPH oxidase membrane assembly, a phenomenon that was decreased in Kupffer cells isolated from leptin receptor knockout mice. In obese mice that were BDCM-exposed, livers showed a significant increase in Kupffer cell activation marker CD68 and, increased necrosis as assessed by levels of isocitrate dehydrogenase, events that were decreased in the absence of leptin or its receptor. In conclusion, our results show that exposure to the disinfection byproduct BDCM in diet-induced obesity augments steatohepatitic injury by potentiating the effects of leptin on oxidative stress, Kupffer cell activation and cell death in the liver. - Highlights: ► BDCM acute exposure sensitizes liver to increased free radical stress in obesity. ► BDCM-induced higher leptin contributes to early steatohepatitic lesions. ► Increased leptin mediates protein

  6. Withaferin A-Induced Apoptosis in Human Breast Cancer Cells Is Mediated by Reactive Oxygen Species

    PubMed Central

    Hahm, Eun-Ryeong; Moura, Michelle B.; Kelley, Eric E.; Van Houten, Bennett; Shiva, Sruti; Singh, Shivendra V.

    2011-01-01

    Withaferin A (WA), a promising anticancer constituent of Ayurvedic medicinal plant Withania somnifera, inhibits growth of MDA-MB-231 and MCF-7 human breast cancer cells in culture and MDA-MB-231 xenografts in vivo in association with apoptosis induction, but the mechanism of cell death is not fully understood. We now demonstrate, for the first time, that WA-induced apoptosis is mediated by reactive oxygen species (ROS) production due to inhibition of mitochondrial respiration. WA treatment caused ROS production in MDA-MB-231 and MCF-7 cells, but not in a normal human mammary epithelial cell line (HMEC). The HMEC was also resistant to WA-induced apoptosis. WA-mediated ROS production as well as apoptotic histone-associated DNA fragment release into the cytosol was significantly attenuated by ectopic expression of Cu,Zn-superoxide dismutase in both MDA-MB-231 and MCF-7 cells. ROS production resulting from WA exposure was accompanied by inhibition of oxidative phosphorylation and inhibition of complex III activity. Mitochondrial DNA-deficient Rho-0 variants of MDA-MB-231 and MCF-7 cells were resistant to WA-induced ROS production, collapse of mitochondrial membrane potential, and apoptosis compared with respective wild-type cells. WA treatment resulted in activation of Bax and Bak in MDA-MB-231 and MCF-7 cells, and SV40 immortalized embryonic fibroblasts derived from Bax and Bak double knockout mouse were significantly more resistant to WA-induced apoptosis compared with fibroblasts derived from wild-type mouse. In conclusion, the present study provides novel insight into the molecular circuitry of WA-induced apoptosis involving ROS production and activation of Bax/Bak. PMID:21853114

  7. Boswellia serrata extract attenuates inflammatory mediators and oxidative stress in collagen induced arthritis.

    PubMed

    Umar, Sadiq; Umar, Khalid; Sarwar, Abu Hasnath Md Golam; Khan, Altaf; Ahmad, Niyaz; Ahmad, Sayeed; Katiyar, Chandra Kant; Husain, Syed Akhtar; Khan, Haider A

    2014-05-15

    Rheumatoid arthritis (RA) is a chronic inflammatory disease which leads to destruction of joints. Current treatment modalities for RA either produce symptomatic relief (NSAIDs) or modify the disease process (DMARDs). Though effective, their use is also limited by their side effects. As a result, the interest in alternative, well tolerated anti-inflammatory remedies has re-emerged. Our aim was to evaluate the antioxidant and antiarthritic activity of Boswellia serrata gum resin extract (BSE) in collagen induced arthritis. Arthritis was induced in male Wistar rats by collagen induced arthritis (CIA) method. BSE was administered at doses of 100 and 200mg/kg body weight once daily for 21 days. The effects of treatment in the rats were assessed by biochemical (articular elastase, MPO, LPO, GSH, catalase, SOD and NO), inflammatory mediators (IL-1β, IL-6, TNF-α, IL-10, IFN-γ and PGE2), and histological studies in joints. BSE was effective in bringing significant changes on all the parameters (articular elastase, MPO, LPO, GSH, catalase, SOD and NO) studied. Oral administration of BSE resulted in significantly reduced levels of inflammatory mediators (IL-1β, IL-6, TNF-α, IFN-γ and PGE2), and increased level of IL-10. The protective effects of BSE against RA were also evident from the decrease in arthritis scoring and bone histology. The abilities to inhibit proinflammatory cytokines and modulation of antioxidant status suggest that the protective effect of Boswellia serrata extract on arthritis in rats might be mediated via the modulation of immune system. PMID:24667331

  8. Phytochromes A and B mediate red-light-induced positive phototropism in roots

    NASA Technical Reports Server (NTRS)

    Kiss, John Z.; Mullen, Jack L.; Correll, Melanie J.; Hangarter, Roger P.

    2003-01-01

    The interaction of tropisms is important in determining the final growth form of the plant body. In roots, gravitropism is the predominant tropistic response, but phototropism also plays a role in the oriented growth of roots in flowering plants. In blue or white light, roots exhibit negative phototropism that is mediated by the phototropin family of photoreceptors. In contrast, red light induces a positive phototropism in Arabidopsis roots. Because this red-light-induced response is weak relative to both gravitropism and negative phototropism, we used a novel device to study phototropism without the complications of a counteracting gravitational stimulus. This device is based on a computer-controlled system using real-time image analysis of root growth and a feedback-regulated rotatable stage. Our data show that this system is useful to study root phototropism in response to red light, because in wild-type roots, the maximal curvature detected with this apparatus is 30 degrees to 40 degrees, compared with 5 degrees to 10 degrees without the feedback system. In positive root phototropism, sensing of red light occurs in the root itself and is not dependent on shoot-derived signals resulting from light perception. Phytochrome (Phy)A and phyB were severely impaired in red-light-induced phototropism, whereas the phyD and phyE mutants were normal in this response. Thus, PHYA and PHYB play a key role in mediating red-light-dependent positive phototropism in roots. Although phytochrome has been shown to mediate phototropism in some lower plant groups, this is one of the few reports indicating a phytochrome-dependent phototropism in flowering plants.

  9. Glucose modulation induces reactive oxygen species and increases P-glycoprotein-mediated multidrug resistance to chemotherapeutics

    PubMed Central

    Seebacher, N A; Richardson, D R; Jansson, P J

    2015-01-01

    Background and Purpose Cancer cells develop resistance to stress induced by chemotherapy. In tumours, a considerable glucose gradient exists, resulting in stress. Notably, hypoxia-inducible factor-1 (HIF-1) is a redox-sensitive transcription factor that regulates P-glycoprotein (Pgp), a crucial drug-efflux transporter involved in multidrug resistance (MDR). Here, we investigated how glucose levels regulate Pgp-mediated drug transport and resistance. Experimental Approach Human tumour cells (KB31, KBV1, A549 and DMS-53) were incubated under glucose starvation to hyperglycaemic conditions. Flow cytometry assessed reactive oxygen species (ROS) generation and Pgp activity. HIF-1α, NF-κB and Pgp expression were assessed by reverse transcriptase-PCR and Western blotting. Fluorescence microscopy examined p65 distribution and a luciferase-reporter assay assessed HIF-1 promoter-binding activity. The effect of glucose-induced stress on Pgp-mediated drug resistance was examined after incubating cells with the chemotherapeutic and Pgp substrate, doxorubicin (DOX), and performing MTT assays validated by viable cell counts. Key Results Changes in glucose levels markedly enhanced cellular ROS and conferred Pgp-mediated drug resistance. Low and high glucose levels increased (i) ROS generation via NADPH oxidase 4 and mitochondrial membrane destabilization; (ii) HIF-1 activity; (iii) nuclear translocation of the NF-κB p65 subunit; and (iv) HIF-1α mRNA and protein levels. Increased HIF-1α could also be due to decreased prolyl hydroxylase protein under these conditions. The HIF-1α target, Pgp, was up-regulated at low and high glucose levels, which led to lower cellular accumulation of Pgp substrate, rhodamine123, and greater resistance to DOX. Conclusions and Implications As tumour cells become glucose-deprived or exposed to high glucose levels, this increases stress, leading to a more aggressive MDR phenotype via up-regulation of Pgp. PMID:25586174

  10. Endocannabinoids, through opioids and prostaglandins, contribute to fever induced by key pyrogenic mediators.

    PubMed

    Fraga, Daniel; Zanoni, Cristiane I S; Zampronio, Aleksander R; Parada, Carlos A; Rae, Giles A; Souza, Glória E P

    2016-01-01

    This study aims to explore the contribution of endocannabinoids on the cascade of mediators involved in LPS-induced fever and to verify the participation of prostaglandins and endogenous opioids in fever induced by anandamide (AEA). Body temperature (Tc) of male Wistar rats was recorded over 6h, using a thermistor probe. Cerebrospinal fluid concentration of PGE2 and β-endorphin were measured by ELISA after the administration of AEA. Intracerebroventricular administration of the CB1 receptor antagonist AM251 (5μg, i.c.v.), reduced the fever induced by IL-1β (3ng, i.c.v.), TNF-α (250ng, i.c.v.), IL-6 (300ng, i.c.v.), corticotrophin release factor (CRH; 2.5μg, i.c.v.) and endothelin (ET)-1 (1pmol, i.c.v.), but not the fever induced by PGE2 (250ng, i.c.v.) or PGF2α (250ng, i.c.v.). Systemic administration of indomethacin (2mgkg(-1), i.p.) or celecoxib (5mgkg(-1), p.o.) reduced the fever induced by AEA (1μg, i.c.v.), while naloxone (1mgkg(-1), s.c.) abolished it. The increases of PGE2 and β-endorphin concentration in the CSF induced by AEA were abolished by the pretreatment of rats with AM251. These results suggest that endocannabinoids are intrinsically involved in the pyretic activity of cytokines (IL-1β, TNF-α, IL-6), CRH and ET-1 but not the PGE2 or PGF2α induced fevers. However, anandamide via CB1 receptor activation induces fever that is dependent on the synthesis of prostaglandin and opioids. PMID:26291402

  11. Neutrophilic oxidative stress mediates organic dust-induced pulmonary inflammation and airway hyperresponsiveness.

    PubMed

    McGovern, Toby K; Chen, Michael; Allard, Benoit; Larsson, Kjell; Martin, James G; Adner, Mikael

    2016-01-15

    Airway exposure to organic dust (OD) from swine confinement facilities induces airway inflammation dominated by neutrophils and airway hyperresponsiveness (AHR). One important neutrophilic innate defense mechanism is the induction of oxidative stress. Therefore, we hypothesized that neutrophils exacerbate airway dysfunction following OD exposure by increasing oxidant burden. BALB/C mice were given intranasal challenges with OD or PBS (1/day for 3 days). Mice were untreated or treated with a neutrophil-depleting antibody, anti-Ly6G, or the antioxidant dimethylthiourea (DMTU) prior to OD exposure. Twenty-four hours after the final exposure, we measured airway responsiveness in response to methacholine (MCh) and collected bronchoalveolar lavage fluid to assess pulmonary inflammation and total antioxidant capacity. Lung tissue was harvested to examine the effect of OD-induced antioxidant gene expression and the effect of anti-Ly6G or DMTU. OD exposure induced a dose-dependent increase of airway responsiveness, a neutrophilic pulmonary inflammation, and secretion of keratinocyte cytokine. Depletion of neutrophils reduced OD-induced AHR. DMTU prevented pulmonary inflammation involving macrophages and neutrophils. Neutrophil depletion and DMTU were highly effective in preventing OD-induced AHR affecting large, conducting airways and tissue elastance. OD induced an increase in total antioxidant capacity and mRNA levels of NRF-2-dependent antioxidant genes, effects that are prevented by administration of DMTU and neutrophil depletion. We conclude that an increase in oxidative stress and neutrophilia is critical in the induction of OD-induced AHR. Prevention of oxidative stress diminishes neutrophil influx and AHR, suggesting that mechanisms driving OD-induced AHR may be dependent on neutrophil-mediated oxidant pathways. PMID:26545900

  12. Protein kinase C-ζ mediates lung injury induced by diesel exhaust particles.

    PubMed

    Caraballo, Juan C; Borcherding, Jennifer; Thorne, Peter S; Comellas, Alejandro P

    2013-03-01

    Recently, we reported that diesel exhaust particles (DEPs) disrupt tight junctions (TJs) in alveolar epithelial cells (AECs) via an increase in reactive oxygen species (ROS). In this study, we investigated the role of protein kinase C (PKC)-ζ activation in DEP-induced lung injury. C57/bl6 mice were instilled intratracheally with 50 μl of saline containing 100 μg of DEPs or titanium dioxide (TiO2). Twenty-four hours later, bronchoalveolar lavage was performed to assess neutrophil counts and protein concentrations. In addition, in vitro experiments were performed in primary rat and human AECs exposed to DEPs (50 μg/cm(2)) for 3 hours. Transepithelial electrical conductance was measured, and TJ protein association was analyzed by immunoprecipitation. To determine whether the overexpression of antioxidants prevented DEP-induced lung injury, AECs and mice were infected with adenoviruses containing catalase and manganese superoxide dismutase (MnSOD) plasmids. In vivo, the overexpression of catalase and MnSOD prevented DEP-induced neutrophil recruitment. The inhibition of PKC-ζ activation also prevented DEP-induced neutrophil recruitment in vivo. In vitro, DEPs activated PKC-ζ in AECs, but not in alveolar macrophages. Using a specific myristolated PKC-ζ pseudosubstrate pepetide (PKC-ζ ps), we showed that PKC-ζ mediated the DEP-induced dissociation of occludin and zonula occludin-1 (ZO1) in rat and human AECs. In addition, the overexpression of constitutively active PKC-ζ induced the dissociation of occludin and ZO1 in AECs. DEP-induced TJ disruption occurs via PKC-ζ. TJ disruption seems to be in part responsible for DEP-induced lung injury. PMID:23221045

  13. Macrophage TNF-α mediates parathion-induced airway hyperreactivity in guinea pigs

    PubMed Central

    Bruun, Donald A.; Jacoby, David B.; van Rooijen, Nico; Lein, Pamela J.; Fryer, Allison D.

    2013-01-01

    Organophosphorus pesticides (OPs) are implicated in human asthma. We previously demonstrated that, at concentrations that do not inhibit acetylcholinesterase activity, the OP parathion causes airway hyperreactivity in guinea pigs as a result of functional loss of inhibitory M2 muscarinic receptors on parasympathetic nerves. Because macrophages are associated with asthma, we investigated whether macrophages mediate parathion-induced M2 receptor dysfunction and airway hyperreactivity. Airway physiology was measured in guinea pigs 24 h after a subcutaneous injection of parathion. Pretreatment with liposome-encapsulated clodronate induced alveolar macrophage apoptosis and prevented parathion-induced airway hyperreactivity in response to electrical stimulation of the vagus nerves. As determined by qPCR, TNF-α and IL-1β mRNA levels were increased in alveolar macrophages isolated from parathion-treated guinea pigs. Parathion treatment of alveolar macrophages ex vivo did not significantly increase IL-1β and TNF-α mRNA but did significantly increase TNF-α protein release. Consistent with these data, pretreatment with the TNF-α inhibitor etanercept but not the IL-1β receptor inhibitor anakinra prevented parathion-induced airway hyperreactivity and protected M2 receptor function. These data suggest a novel mechanism of OP-induced airway hyperreactivity in which low-level parathion activates macrophages to release TNF-α-causing M2 receptor dysfunction and airway hyperreactivity. These observations have important implications regarding therapeutic approaches for treating respiratory disease associated with OP exposures. PMID:23377347

  14. Apoptosis signal-regulating kinase 1 mediates denbinobin-induced apoptosis in human lung adenocarcinoma cells

    PubMed Central

    Kuo, Chen-Tzu; Chen, Bing-Chang; Yu, Chung-Chi; Weng, Chih-Ming; Hsu, Ming-Jen; Chen, Chien-Chih; Chen, Mei-Chieh; Teng, Che-Ming; Pan, Shiow-Lin; Bien, Mauo-Ying; Shih, Chung-Hung; Lin, Chien-Huang

    2009-01-01

    In the present study, we explore the role of apoptosis signal-regulating kinase 1 (ASK1) in denbinobin-induced apoptosis in human lung adenocarcinoma (A549) cells. Denbinobin-induced cell apoptosis was attenuated by an ASK1 dominant-negative mutant (ASK1DN), two antioxidants (N-acetyl-L-cysteine (NAC) and glutathione (GSH)), a c-Jun N-terminal kinase (JNK) inhibitor (SP600125), and an activator protein-1 (AP-1) inhibitor (curcumin). Treatment of A549 cells with denbinobin caused increases in ASK1 activity and reactive oxygen species (ROS) production, and these effects were inhibited by NAC and GSH. Stimulation of A549 cells with denbinobin caused JNK activation; this effect was markedly inhibited by NAC, GSH, and ASK1DN. Denbinobin induced c-Jun phosphorylation, the formation of an AP-1-specific DNA-protein complex, and Bim expression. Bim knockdown using a bim short interfering RNA strategy also reduced denbinobin-induced A549 cell apoptosis. The denbinobin-mediated increases in c-Jun phosphorylation and Bim expression were inhibited by NAC, GSH, SP600125, ASK1DN, JNK1DN, and JNK2DN. These results suggest that denbinobin might activate ASK1 through ROS production to cause JNK/AP-1 activation, which in turn induces Bim expression, and ultimately results in A549 cell apoptosis. PMID:19405983

  15. Small-molecule-mediated rescue of protein function by an inducible proteolytic shunt

    PubMed Central

    Pratt, Matthew R.; Schwartz, Edmund C.; Muir, Tom W.

    2007-01-01

    Controlling protein function through posttranslational manipulations has emerged as an attractive complementary technology to existing genetic systems. Often these methods involve developing pharmacological agents to probe protein function without the need to generate a unique compound for each protein family. One common strategy uses small molecules that act as chemical inducers of dimerization by mediating the interaction of two proteins. Herein we report the use of a chemical inducer of dimerization for the development of a posttranslational technology for the manipulation of protein function. This system, split ubiquitin for the rescue of function (SURF), places the complementation of genetically split ubiquitin under the control of rapamycin-induced dimerization of FK506-binding protein and FKBP12-rapamycin-binding protein. Before complementation a “degron” dooms a protein of interest for destruction by the proteasome. Addition of rapamycin results in a proteolytic shunt away from degradation by inducing ubiquitin complementation and cleavage of the protein of interest from the degron. Importantly, the native protein is rescued. We characterized this system with firefly luciferase and went on to apply it to members of three important classes of proteins: proteases (caspase-3), kinases (v-Src), and transcription factors (Smad3). This general strategy should allow for inducible rescue of a variety of proteins in such a way that their native structure and function are maintained. PMID:17563385

  16. Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney.

    PubMed

    Sheng, Lili; Yang, Min; Ding, Wei; Zhang, Minmin; Niu, Jianying; Qiao, Zhongdong; Gu, Yong

    2016-08-01

    Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangial cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis. PMID:27317889

  17. Analysis of methods and models for assessing the direct and indirect economic impacts of CO/sub 2/-induced environmental changes in the agricultural sector of the US economy

    SciTech Connect

    Callaway, J.M.; Cronin, F.J.; Currie, J.W.; Tawil, J.

    1982-08-01

    The overall purpose of this research was to assist the US Department of Energy (DOE) in developing methods for assessing the direct and indirect economic impacts due to the effects of increases in the ambient concentration of CO/sub 2/ on agricultural production. First, a comprehensive literature search was undertaken to determine what types of models and methods have been developed, which could be effectively used to conduct assessments of the direct and indirect economic impacts of CO/sub 2/ buildup. Specific attention was focused upon models and methods for assessing the physical impacts of CO/sub 2/-induced environmental changes on crop yields; national and multi-regional agricultural sector models; and macroeconomic models of the US economy. The second task involved a thorough investigation of the research efforts being conducted by other public and private sector organizations in order to determine how more recent analytical methods being developed outside of DOE could be effectively integrated into a more comprehensive analysis of the direct economic impacts of CO/sub 2/ buildup. The third and final task involved synthesizing the information gathered in the first two tasks into a systematic framework for assessing the direct and indirect economic impacts of CO/sub 2/-induced environmental changes originating in the agricultural sector of the US economy. It is concluded that the direct economic impacts of CO/sub 2/ on the agricultural sector and the indirect economic impacts caused by spillover effects from agriculture to other sectors of the economy will be pervasive; however, the direction and magnitude of these impacts on producers and consumers cannot be determined a priori.

  18. DAPT mediates atoh1 expression to induce hair cell-like cells

    PubMed Central

    Ren, Hongmiao; Guo, Weiwei; Liu, Wei; Gao, Weiqiang; Xie, Dinghua; Yin, Tuanfang; Yang, Shiming; Ren, Jihao

    2016-01-01

    Hearing loss is currently an incurable degenerative disease characterized by a paucity of hair cells (HCs), which cannot be spontaneously replaced in mammals. Recent technological advancements in gene therapy and local drug delivery have shed new light for hearing loss. Atoh1, also known as Math1, Hath1, and Cath1, is a proneural basic helix-loop-helix (bHLH) transcription factor that is essential for HC differentiation. At various stages in development, Atoh1 activity is sufficient to drive HC differentiation in the cochlea. Thus, Atoh1 related gene therapy is the most promising option for HC induction. DAPT, an inhibitor of Notch signaling, enhances the expression of Atoh1 indirectly, which in turn promotes the induction of a HC fate. Here, we show that DAPT cooperates with Atoh1 to synergistically promote HC fate in ependymal cells in vitro and promote hair cell regeneration in the cultured basilar membrane (BM) which mimics the microenvironment in vivo. Taken together, our findings demonstrated that DAPT is sufficient to induce HC-like cells via enhancing of the expression of Atoh1 to inhibit the progression of HC apoptosis and to induce new HC formation. PMID:27158355

  19. DAPT mediates atoh1 expression to induce hair cell-like cells.

    PubMed

    Ren, Hongmiao; Guo, Weiwei; Liu, Wei; Gao, Weiqiang; Xie, Dinghua; Yin, Tuanfang; Yang, Shiming; Ren, Jihao

    2016-01-01

    Hearing loss is currently an incurable degenerative disease characterized by a paucity of hair cells (HCs), which cannot be spontaneously replaced in mammals. Recent technological advancements in gene therapy and local drug delivery have shed new light for hearing loss. Atoh1, also known as Math1, Hath1, and Cath1, is a proneural basic helix-loop-helix (bHLH) transcription factor that is essential for HC differentiation. At various stages in development, Atoh1 activity is sufficient to drive HC differentiation in the cochlea. Thus, Atoh1 related gene therapy is the most promising option for HC induction. DAPT, an inhibitor of Notch signaling, enhances the expression of Atoh1 indirectly, which in turn promotes the induction of a HC fate. Here, we show that DAPT cooperates with Atoh1 to synergistically promote HC fate in ependymal cells in vitro and promote hair cell regeneration in the cultured basilar membrane (BM) which mimics the microenvironment in vivo. Taken together, our findings demonstrated that DAPT is sufficient to induce HC-like cells via enhancing of the expression of Atoh1 to inhibit the progression of HC apoptosis and to induce new HC formation. PMID:27158355

  20. STAT5 is a key transcription factor for IL-3-mediated inhibition of RANKL-induced osteoclastogenesis

    PubMed Central

    Lee, Jongwon; Seong, Semun; Kim, Jung Ha; Kim, Kabsun; Kim, Inyoung; Jeong, Byung-chul; Nam, Kwang-Il; Kim, Kyung Keun; Hennighausen, Lothar; Kim, Nacksung

    2016-01-01

    Among the diverse cytokines involved in osteoclast differentiation, interleukin (IL)-3 inhibits RANKL-induced osteoclastogenesis. However, the mechanism underlying IL-3-mediated inhibition of osteoclast differentiation is not fully understood. Here we demonstrate that the activation of signal transducers and activators of transcription 5 (STAT5) by IL-3 inhibits RANKL-induced osteoclastogenesis through the induction of the expression of Id genes. We found that STAT5 overexpression inhibited RANKL-induced osteoclastogenesis. However, RANKL did not regulate the expression or activation of STAT5 during osteoclast differentiation. STAT5 deficiency prevented IL-3-mediated inhibition of osteoclastogenesis, suggesting a key role of STAT5 in IL-3-mediated inhibition of osteoclast differentiation. In addition, IL-3-induced STAT5 activation upregulated the expression of Id1 and Id2, which are negative regulators of osteoclastogenesis. Overexpression of ID1 or ID2 in STAT5-deficient cells reversed osteoclast development recovered from IL-3-mediated inhibition. Importantly, microcomputed tomography and histomorphometric analysis revealed that STAT5 conditional knockout mice showed reduced bone mass, with an increased number of osteoclasts. Furthermore, IL-3 inhibited RANKL-induced osteoclast differentiation less effectively in the STAT5 conditional knockout mice than in the wild-type mice after RANKL injection. Taken together, our findings indicate that STAT5 contributes to the remarkable IL-3-mediated inhibition of RANKL-induced osteoclastogenesis by activating Id genes and their associated pathways. PMID:27485735

  1. STAT5 is a key transcription factor for IL-3-mediated inhibition of RANKL-induced osteoclastogenesis.

    PubMed

    Lee, Jongwon; Seong, Semun; Kim, Jung Ha; Kim, Kabsun; Kim, Inyoung; Jeong, Byung-Chul; Nam, Kwang-Il; Kim, Kyung Keun; Hennighausen, Lothar; Kim, Nacksung

    2016-01-01

    Among the diverse cytokines involved in osteoclast differentiation, interleukin (IL)-3 inhibits RANKL-induced osteoclastogenesis. However, the mechanism underlying IL-3-mediated inhibition of osteoclast differentiation is not fully understood. Here we demonstrate that the activation of signal transducers and activators of transcription 5 (STAT5) by IL-3 inhibits RANKL-induced osteoclastogenesis through the induction of the expression of Id genes. We found that STAT5 overexpression inhibited RANKL-induced osteoclastogenesis. However, RANKL did not regulate the expression or activation of STAT5 during osteoclast differentiation. STAT5 deficiency prevented IL-3-mediated inhibition of osteoclastogenesis, suggesting a key role of STAT5 in IL-3-mediated inhibition of osteoclast differentiation. In addition, IL-3-induced STAT5 activation upregulated the expression of Id1 and Id2, which are negative regulators of osteoclastogenesis. Overexpression of ID1 or ID2 in STAT5-deficient cells reversed osteoclast development recovered from IL-3-mediated inhibition. Importantly, microcomputed tomography and histomorphometric analysis revealed that STAT5 conditional knockout mice showed reduced bone mass, with an increased number of osteoclasts. Furthermore, IL-3 inhibited RANKL-induced osteoclast differentiation less effectively in the STAT5 conditional knockout mice than in the wild-type mice after RANKL injection. Taken together, our findings indicate that STAT5 contributes to the remarkable IL-3-mediated inhibition of RANKL-induced osteoclastogenesis by activating Id genes and their associated pathways. PMID:27485735

  2. Mediation of poly(ADP-ribose) polymerase-1-dependent cell death by apoptosis-inducing factor.

    PubMed

    Yu, Seong-Woon; Wang, Hongmin; Poitras, Marc F; Coombs, Carmen; Bowers, William J; Federoff, Howard J; Poirier, Guy G; Dawson, Ted M; Dawson, Valina L

    2002-07-12

    Poly(ADP-ribose) polymerase-1 (PARP-1) protects the genome by functioning in the DNA damage surveillance network. PARP-1 is also a mediator of cell death after ischemia-reperfusion injury, glutamate excitotoxicity, and various inflammatory processes. We show that PARP-1 activation is required for translocation of apoptosis-inducing factor (AIF) from the mitochondria to the nucleus and that AIF is necessary for PARP-1-dependent cell death. N-methyl-N'-nitro-N-nitrosoguanidine, H2O2, and N-methyl-d-aspartate induce AIF translocation and cell death, which is prevented by PARP inhibitors or genetic knockout of PARP-1, but is caspase independent. Microinjection of an antibody to AIF protects against PARP-1-dependent cytotoxicity. These data support a model in which PARP-1 activation signals AIF release from mitochondria, resulting in a caspase-independent pathway of programmed cell death. PMID:12114629

  3. INDUCIBLE RNAi-MEDIATED GENE SILENCING USING NANOSTRUCTURED GENE DELIVERY ARRAYS

    SciTech Connect

    Mann, David George James; McKnight, Timothy E; Mcpherson, Jackson; Hoyt, Peter R; Melechko, Anatoli Vasilievich; Simpson, Michael L; Sayler, Gary Steven

    2008-01-01

    RNA interference has become a powerful biological tool over the last decade. In this study, a tetracycline-inducible shRNA vector system was designed for silencing CFP expression and introduced alongside the yfp marker gene into Chinese hamster ovary cells using spatially indexed vertically aligned carbon nanofiber arrays (VACNFs) in a gene delivery process termed impalefection. The VACNF architecture provided simultaneous delivery of multiple genes, subsequent adherence and proliferation of interfaced cells, and repeated monitoring of single cells over time. 24 hours after nanofiber-mediated delivery, 53.1% 10.4% of the cells that expressed the yfp marker gene were also fully silenced by the inducible CFP-silencing shRNA vector. Additionally, efficient CFP-silencing was observed in single cells among a population of cells that remained CFP-expressing. This effective transient expression system enables rapid analysis of gene silencing effects using RNAi in single cells and cell populations.

  4. Cannabinoid CB1 receptor mediates glucocorticoid effects on hormone secretion induced by volume and osmotic changes.

    PubMed

    Ruginsk, S G; Uchoa, E T; Elias, L L K; Antunes-Rodrigues, J

    2012-02-01

    The present study provides the first in vivo evidence that the cannabinoid CB(1) receptor mediates the effects of dexamethasone on hormone release induced by changes in circulating volume and osmolality. Male adult rats were administered with the CB(1) receptor antagonist rimonabant (10 mg/Kg, p.o.), followed or not in 1 hour by dexamethasone (1 mg/Kg, i.p.). Extracellular volume expansion (EVE, 2 mL/100 g of body weight, i.v.) was performed 2 hours after dexamethasone or vehicle treatment using either isotonic (I-EVE, 0.15 mol/L) or hypertonic (H-EVE, 0.30 mol/L) NaCl solution. Five minutes after EVE, animals were decapitated and trunk blood was collected for all plasma measurements. Rimonabant potentiated oxytocin (OT) secretion induced by H-EVE and completely reversed the inhibitory effects of dexamethasone in response to the same stimulus. These data suggest that glucocorticoid modulation of OT release is mediated by the CB(1) receptor. Although dexamethasone did not affect vasopressin (AVP) secretion induced by H-EVE, the administration of rimonabant potentiated AVP release in response to the same stimulus, supporting the hypothesis that the CB(1) receptor regulates AVP secretion independently of glucocorticoid-mediated signalling. Dexamethasone alone did not affect atrial natriuretic peptide (ANP) release stimulated by I-EVE or H-EVE. However, pretreatment with rimonabant potentiated ANP secretion induced by H-EVE, suggesting a possible role for the CB(1) receptor in the control of peripheral factors that modulate cardiovascular function. Rimonabant also reversed the inhibitory effects of dexamethasone on H-EVE-induced corticosterone secretion, reinforcing the hypothesis that the CB(1) receptor may be involved in the negative feedback exerted by glucocorticoids on the activity of the hypothalamic-pituitary-adrenal axis. Collectively, the results of the present study indicate that the CB(1) receptor modulates neurohypophyseal hormone secretion and

  5. Sirtuins-mediators of maternal obesity-induced complications in offspring?

    PubMed

    Nguyen, Long T; Chen, Hui; Pollock, Carol A; Saad, Sonia

    2016-04-01

    Obesity is a complex metabolic disease, attributed to diverse and interactive genetic and environmental factors. The associated health consequences of obesity are pleiotropic, with individuals being more susceptible to chronic diseases such as type 2 diabetes mellitus, hypertension, and lipotoxicity-related chronic diseases. The contribution of maternal obesity to the offspring's predisposition to both obesity and its complications is increasingly recognized. Understanding the mechanisms underlying these "transmissible" effects is critical to develop therapeutic interventions to reduce the risk for "programmed" obesity. Sirtuins (SIRTs), particularly SIRT1 and SIRT3, are NAD(+)-dependent deacetylases that regulate metabolic balance and stress responses in both central and peripheral tissues, of which dysregulation is a well-established mediator for the development and effects of obesity. Nevertheless, their implication in the transmissible effects of maternal obesity across generations remains largely elusive. In this review, we examine multiple pathways and systems that are likely to mediate such effects, with particular emphasis on the role of SIRTs.-Nguyen, L. T., Chen, H., Pollock, C. A., Saad, S. Sirtuins-mediators of maternal obesity-induced complications in offspring? PMID:26667041

  6. Rac-mediated Stimulation of Phospholipase Cγ2 Amplifies B Cell Receptor-induced Calcium Signaling.

    PubMed

    Walliser, Claudia; Tron, Kyrylo; Clauss, Karen; Gutman, Orit; Kobitski, Andrei Yu; Retlich, Michael; Schade, Anja; Röcker, Carlheinz; Henis, Yoav I; Nienhaus, G Ulrich; Gierschik, Peter

    2015-07-10

    The Rho GTPase Rac is crucially involved in controlling multiple B cell functions, including those regulated by the B cell receptor (BCR) through increased cytosolic Ca(2+). The underlying molecular mechanisms and their relevance to the functions of intact B cells have thus far remained unknown. We have previously shown that the activity of phospholipase Cγ2 (PLCγ2), a key constituent of the BCR signalosome, is stimulated by activated Rac through direct protein-protein interaction. Here, we use a Rac-resistant mutant of PLCγ2 to functionally reconstitute cultured PLCγ2-deficient DT40 B cells and to examine the effects of the Rac-PLCγ2 interaction on BCR-mediated changes of intracellular Ca(2+) and regulation of Ca(2+)-regulated and nuclear-factor-of-activated-T-cell-regulated gene transcription at the level of single, intact B cells. The results show that the functional Rac-PLCγ2 interaction causes marked increases in the following: (i) sensitivity of B cells to BCR ligation; (ii) BCR-mediated Ca(2+) release from intracellular stores; (iii) Ca(2+) entry from the extracellular compartment; and (iv) nuclear translocation of the Ca(2+)-regulated nuclear factor of activated T cells. Hence, Rac-mediated stimulation of PLCγ2 activity serves to amplify B cell receptor-induced Ca(2+) signaling. PMID:25903139

  7. TRPM2 channels in alveolar epithelial cells mediate bleomycin-induced lung inflammation.

    PubMed

    Yonezawa, Ryo; Yamamoto, Shinichiro; Takenaka, Miki; Kage, Yukiko; Negoro, Takaharu; Toda, Takahiro; Ohbayashi, Masayuki; Numata, Tomohiro; Nakano, Yasuko; Yamamoto, Toshinori; Mori, Yasuo; Ishii, Masakazu; Shimizu, Shunichi

    2016-01-01

    Lung inflammation is a major adverse effect of therapy with the antitumor drug bleomycin (BLM). Transient receptor potential melastatin 2 (TRPM2) is a Ca(2+)-permeable channel that is activated by oxidative stress through the production of ADP-ribose. We herein investigated whether TRPM2 channels contributed to BLM-induced lung inflammation. The intratracheal instillation of BLM into wild-type (WT) mice increased the number of polymorphonuclear leukocytes (PMNs) and inflammatory cytokine levels in the lung. Increases in inflammatory markers in WT mice were markedly reduced in trpm2 knockout (KO) mice, which demonstrated that the activation of TRPM2 channels was involved in BLM-induced lung inflammation. The expression of TRPM2 mRNA was observed in alveolar macrophages, alveolar epithelial cells, and lung fibroblasts. Actually, TRPM2 protein was expressed in lung tissues. Of these, TRPM2 channels in epithelial cells were activated by the addition of H2O2 following a BLM pretreatment, resulting in the secretion of macrophage inflammatory protein-2 (MIP-2). The H2O2-induced activation of TRPM2 by the BLM pretreatment was blocked by the poly(ADP-ribose) polymerase (PARP) inhibitors PJ34 and 3-aminobenzamide. The accumulation of poly(ADP-ribose) in the nucleus, a marker for ADP-ribose production, was strongly induced by H2O2 following the BLM pretreatment. Furthermore, administration of PRAP inhibitors into WT mice markedly reduced recruitment of inflammatory cells and MIP-2 secretion induced by BLM instillation. These results suggest that the induction of MIP-2 secretion through the activation of TRPM2 channels in alveolar epithelial cells is an important mechanism in BLM-induced lung inflammation, and the TRPM2 activation is likely to be mediated by ADP-ribose production via PARP pathway. TRPM2 channels may be new therapeutic target for BLM-induced lung inflammation. PMID:26600069

  8. TBT-induced imposex in marine neogastropods is mediated by an increasing androgen level

    NASA Astrophysics Data System (ADS)

    Bettin, C.; Oehlmann, J.; Stroben, E.

    1996-09-01

    Tributyltin (TBT) exposure at different concentrations (5, 60, and 100 ng TBT as Sn/l) induces a concentration- and time-dependent imposex (=pseudohermaphroditism) development in female Nucella lapillus and Hinia reticulata. In both species the average imposex stage, termed as vas deferens sequence (VDS) index, and the average female penis length increases with increasing TBT concentration and duration of TBT exposure. Testosterone added at a concentration of 500 ng/l induces a faster and more intensive imposex development compared to that induced by the TBT concentrations used in the present experiments. Radioimmunological determination of endogenous steroid content reveals increasing testosterone titres in female gastropods exposed to TBT which correlate with the TBT concentration used and the duration of the experiment. The most marked and highest increase of the endogenous testosterone level is exhibited by females, of both species exposed to testosterone. Simulataneous exposure to TBT and to the antiandrogen cyproterone acetate which suppresses imposex development completely in N. lapillus and reduces imposex development strongly in H. reticulata proves that the imposex-inducing effects of TBT are mediated by an increasing androgen level and are not caused directly by the organotin compound itself. Further-more, TBT-induced imposex development can be suppressed in both snails by adding estrogens to the aqueous medium. These observations suggest that TBT causes an inhibition of the cytochrome P-450 dependent aromatase system which catalyses the aromatization of androgens to estrogens. The increase of the androgen content or the shift of the androgen-estrogen balance in favour of androgens induces the development of pseudohermaphroditism in marine prosobranchs. Artificial inhibition of the cytochrome P-450 dependent aromatase system using SH 489 (1-methyl-1,4-androstadiene-3,17-dione) as a steroidal aromatase inhibitor and flavone as a nonsteroidal aromatase

  9. TRPM8 is the principal mediator of menthol-induced analgesia of acute and inflammatory pain.

    PubMed

    Liu, Boyi; Fan, Lu; Balakrishna, Shrilatha; Sui, Aiwei; Morris, John B; Jordt, Sven-Eric

    2013-10-01

    Menthol, the cooling natural product of peppermint, is widely used in medicinal preparations for the relief of acute and inflammatory pain in sports injuries, arthritis, and other painful conditions. Menthol induces the sensation of cooling by activating TRPM8, an ion channel in cold-sensitive peripheral sensory neurons. Recent studies identified additional targets of menthol, including the irritant receptor, TRPA1, voltage-gated ion channels and neurotransmitter receptors. It remains unclear which of these targets contribute to menthol-induced analgesia, or to the irritating side effects associated with menthol therapy. Here, we use genetic and pharmacological approaches in mice to probe the role of TRPM8 in analgesia induced by L-menthol, the predominant analgesic menthol isomer in medicinal preparations. L-menthol effectively diminished pain behavior elicited by chemical stimuli (capsaicin, acrolein, acetic acid), noxious heat, and inflammation (complete Freund's adjuvant). Genetic deletion of TRPM8 completely abolished analgesia by L-menthol in all these models, although other analgesics (acetaminophen) remained effective. Loss of L-menthol-induced analgesia was recapitulated in mice treated with a selective TRPM8 inhibitor, AMG2850. Selective activation of TRPM8 with WS-12, a menthol derivative that we characterized as a specific TRPM8 agonist in cultured sensory neurons and in vivo, also induced TRPM8-dependent analgesia of acute and inflammatory pain. L-menthol- and WS-12-induced analgesia was blocked by naloxone, suggesting activation of endogenous opioid-dependent analgesic pathways. Our data show that TRPM8 is the principal mediator of menthol-induced analgesia of acute and inflammatory pain. In contrast to menthol, selective TRPM8 agonists may produce analgesia more effectively, with diminished side effects. PMID:23820004

  10. TRPM8 is the Principal Mediator of Menthol-induced Analgesia of Acute and Inflammatory Pain

    PubMed Central

    Liu, Boyi; Fan, Lu; Balakrishna, Shrilatha; Sui, Aiwei; Morris, John B.; Jordt, Sven-Eric

    2013-01-01

    Menthol, the cooling natural product of peppermint, is widely used in medicinal preparations for the relief of acute and inflammatory pain in sports injuries, arthritis and other painful conditions. Menthol induces the sensation of cooling by activating TRPM8, an ion channel in cold-sensitive peripheral sensory neurons. Recent studies identified additional targets of menthol, including the irritant receptor, TRPA1, voltage-gated ion channels and neurotransmitter receptors. It remains unclear which of these targets contribute to menthol-induced analgesia, or to the irritating side effects associated with menthol therapy. Here, we use genetic and pharmacological approaches in mice to probe the role of TRPM8 in analgesia induced by L-menthol, the predominant analgesic menthol isomer in medicinal preparations. L-menthol effectively diminished pain behavior elicited by chemical stimuli (capsaicin, acrolein, acetic acid), noxious heat and inflammation (complete Freund's adjuvant). Genetic deletion of TRPM8 completely abolished analgesia by L-menthol in all these models, while other analgesics (acetaminophen) remained effective. Loss of L-menthol-induced analgesia was recapitulated in mice treated with a selective TRPM8 inhibitor, AMG2850. Selective activation of TRPM8 with WS-12, a menthol derivative we characterized as a specific TRPM8 agonist in cultured sensory neurons and in vivo, also induced TRPM8-dependent analgesia of acute and inflammatory pain. L-menthol and WS-12 induced analgesia was blocked by naloxone, suggesting activation of endogenous opioid-dependent analgesic pathways. Our data show that TRPM8 is the principal mediator of menthol-induced analgesia of acute and inflammatory pain. In contrast to menthol, selective TRPM8 agonists may produce analgesia more effectively with diminished side effects. PMID:23820004

  11. Toll-Like Receptor 4 Signaling Pathway Mediates Inhalant Organic Dust-Induced Bone Loss.

    PubMed

    Staab, Elizabeth; Thiele, Geoffrey M; Clarey, Dillon; Wyatt, Todd A; Romberger, Debra J; Wells, Adam D; Dusad, Anand; Wang, Dong; Klassen, Lynell W; Mikuls, Ted R; Duryee, Michael J; Poole, Jill A

    2016-01-01

    Agriculture workers have increased rates of airway and skeletal disease. Inhalant exposure to agricultural organic dust extract (ODE) induces bone deterioration in mice; yet, mechanisms underlying lung-bone crosstalk remain unclear. Because Toll-like receptor 2 (TLR2) and TLR4 are important in mediating the airway consequences of ODE, this study investigated their role in regulating bone responses. First, swine facility ODE stimulated wild-type (WT) bone marrow macrophages to form osteoclasts, and this finding was inhibited in TLR4 knock-out (KO), but not TLR2 KO cells. Next, using an established intranasal inhalation exposure model, WT, TLR2 KO and TLR4 KO mice were treated daily with ODE or saline for 3 weeks. ODE-induced airway neutrophil influx and cytokine/chemokine release were similarly reduced in TLR2 and TLR4 KO animals as compared to WT mice. Utilizing micro-computed tomography (CT), analysis of tibia showed loss of bone mineral density, volume and deterioration of bone micro-architecture and mechanical strength induced by ODE in WT mice were significantly reduced in TLR4 but not TLR2 KO animals. Bone marrow osteoclast precursor cell populations were analyzed by flow cytometry from exposed animals. In WT animals, exposure to inhalant ODE increased osteoclast precursor cell populations as compared to saline, an effect that was reduced in TLR4 but not TLR2 KO mice. These results show that TLR2 and TLR4 pathways mediate ODE-induced airway inflammation, but bone deterioration consequences following inhalant ODE treatment is strongly dependent upon TLR4. Thus, the TLR4 signaling pathway appears critical in regulating the lung-bone inflammatory axis to microbial component-enriched organic dust exposures. PMID:27479208

  12. Adenylyl cyclase 6 mediates loading-induced bone adaptation in vivo

    PubMed Central

    Lee, Kristen L.; Hoey, David A.; Spasic, Milos; Tang, Tong; Hammond, H. Kirk; Jacobs, Christopher R.

    2014-01-01

    Primary cilia are single, nonmotile, antenna-like structures extending from the apical membrane of most mammalian cells. They may mediate mechanotransduction, the conversion of external mechanical stimuli into biochemical intracellular signals. Previously we demonstrated that adenylyl cyclase 6 (AC6), a membrane-bound enzyme enriched in primary cilia of MLO-Y4 osteocyte-like cells, may play a role in a primary cilium-dependent mechanism of osteocyte mechanotransduction in vitro. In this study, we determined whether AC6 deletion impairs loading-induced bone formation in vivo. Skeletally mature mice with a global knockout of AC6 exhibited normal bone morphology and responded to osteogenic chemical stimuli similar to wild-type mice. Following ulnar loading over 3 consecutive days, bone formation parameters were assessed using dynamic histomorphometry. Mice lacking AC6 formed significantly less bone than control animals (41% lower bone formation rate). Furthermore, there was an attenuated flow-induced increase in COX-2 mRNA expression levels in primary bone cells isolated from AC6 knockout mice compared to controls (1.3±0.1- vs. 2.6±0.2-fold increase). Collectively, these data indicate that AC6 plays a role in loading-induced bone adaptation, and these findings are consistent with our previous studies implicating primary cilia and AC6 in a novel mechanism of osteocyte mechanotransduction.—Lee, K. L., Hoey, D. A., Spasic, M., Tang, T., Hammond, H. K., Jacobs, C. R. Adenylyl cyclase 6 mediates loading-induced bone adaptation in vivo. PMID:24277577

  13. Colon distention induces persistent visceral hypersensitivity by mechanotranscription of pain mediators in colonic smooth muscle cells.

    PubMed

    Lin, You-Min; Fu, Yu; Wu, Chester C; Xu, Guang-Yin; Huang, Li-Yen; Shi, Xuan-Zheng

    2015-03-01

    Abdominal pain and distention are major complaints in irritable bowel syndrome. Abdominal distention is mainly attributed to intraluminal retention of gas or solid contents, which may cause mechanical stress to the gut wall. Visceral hypersensitivity (VHS) may account for abdominal pain. We sought to determine whether tonic colon distention causes persistent VHS and if so whether mechanical stress-induced expression (mechanotranscription) of pain mediators in colonic smooth muscle cells (SMCs) plays a role in VHS. Human colonic SMCs were isolated and stretched in vitro to investigate whether mechanical stress upregulates expression of the pain mediator cyclooxygenase-2 (COX-2). Rat colon was distended with a 5-cm-long balloon, and gene expression of COX-2, visceromotor response (VMR), and sensory neuron excitability were determined. Static stretch of colonic SMCs induced marked expression of COX-2 mRNA and protein in a force- and time-dependent manner. Subnoxious tonic distention of the distal colon at ∼30-40 mmHg for 20 or 40 min induced COX-2 expression and PGE2 production in colonic smooth muscle, but not in the mucosa layer. Lumen distention also increased VMR in a force- and time-dependent manner. The increase of VMR persisted for at least 3 days. Patch-clamp experiments showed that the excitability of colon projecting sensory neurons in the dorsal root ganglia was markedly augmented, 24 h after lumen distention. Administration of COX-2 inhibitor NS-398 partially but significantly attenuated distention-induced VHS. In conclusion, tonic lumen distention upregulates expression of COX-2 in colonic SMC, and COX-2 contributes to persistent VHS. PMID:25540231

  14. Nickel nanowires induced and reactive oxygen species mediated apoptosis in human pancreatic adenocarcinoma cells

    PubMed Central

    Hossain, Md. Zakir; Kleve, Maurice G

    2011-01-01

    Background The ability to evade apoptosis is one of the key properties of cancer. The apoptogenic effect of nickel nanowires (Ni NWs) on cancer cell lines has never been adequately addressed. Due to the unique physicochemical characteristics of Ni NWs, we envision the development of a novel anticancer therapeutics specifically for pancreatic cancer. Thus, we investigated whether Ni NWs induce ROS-mediated apoptosis in human pancreatic adenocarcinoma (Panc-1) cells. Methods In this study Ni NWs were fabricated using the electrodeposition method. Synthesized Ni NWs were physically characterized by energy dispersive X-ray analysis, UV-Vis spectroscopy of NanoDrop 2000 (UV-Vis), magnetization study, scanning electron microscopy, and transmission electron microscopy. Assessment of morphological apoptotic characteristics by phase contrast microscopy (PCM), Ni-NWs-induced apoptosis staining with ethidium bromide (EB) and acridine orange (AO) followed by fluorescence microscopy (FM) was performed. For molecular biological and biochemical characterization, Panc-1 cell culture and cytotoxic effect of Ni NWs were determined by using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Quantitative apoptosis was analyzed by flow cytometry staining with propidium iodide through cell cycle arrest and generation of ROS using 2′, 7′-dichlorofluorescein diacetate fluorescence intensity. In all experiments, Panc-1 cancer cells without any treatment were used as the negative controls. Results The intracellular uptake of Ni NWs through endocytosis by Panc-1 cells was observed by PCM. EB and AO staining of FM and MTT assay qualitatively and quantitatively confirmed the extent of apoptosis. Flow cytometric cell cycle arrest and ROS generation indicated Ni NWs as inducers of apoptotic cell death. Conclusion We investigated the role of Ni NWs as inducers of ROS-mediated apoptosis in Panc-1 cells. These results suggested that Ni NWs could be an effective

  15. Toll-Like Receptor 4 Signaling Pathway Mediates Inhalant Organic Dust-Induced Bone Loss

    PubMed Central

    Staab, Elizabeth; Thiele, Geoffrey M.; Clarey, Dillon; Wyatt, Todd A.; Romberger, Debra J.; Wells, Adam D.; Dusad, Anand; Wang, Dong; Klassen, Lynell W.; Mikuls, Ted R.; Duryee, Michael J.; Poole, Jill A.

    2016-01-01

    Agriculture workers have increased rates of airway and skeletal disease. Inhalant exposure to agricultural organic dust extract (ODE) induces bone deterioration in mice; yet, mechanisms underlying lung-bone crosstalk remain unclear. Because Toll-like receptor 2 (TLR2) and TLR4 are important in mediating the airway consequences of ODE, this study investigated their role in regulating bone responses. First, swine facility ODE stimulated wild-type (WT) bone marrow macrophages to form osteoclasts, and this finding was inhibited in TLR4 knock-out (KO), but not TLR2 KO cells. Next, using an established intranasal inhalation exposure model, WT, TLR2 KO and TLR4 KO mice were treated daily with ODE or saline for 3 weeks. ODE-induced airway neutrophil influx and cytokine/chemokine release were similarly reduced in TLR2 and TLR4 KO animals as compared to WT mice. Utilizing micro-computed tomography (CT), analysis of tibia showed loss of bone mineral density, volume and deterioration of bone micro-architecture and mechanical strength induced by ODE in WT mice were significantly reduced in TLR4 but not TLR2 KO animals. Bone marrow osteoclast precursor cell populations were analyzed by flow cytometry from exposed animals. In WT animals, exposure to inhalant ODE increased osteoclast precursor cell populations as compared to saline, an effect that was reduced in TLR4 but not TLR2 KO mice. These results show that TLR2 and TLR4 pathways mediate ODE-induced airway inflammation, but bone deterioration consequences following inhalant ODE treatment is strongly dependent upon TLR4. Thus, the TLR4 signaling pathway appears critical in regulating the lung-bone inflammatory axis to microbial component-enriched organic dust exposures. PMID:27479208

  16. Glial cell-expressed mechanosensitive channel TRPV4 mediates infrasound-induced neuronal impairment.

    PubMed

    Shi, Ming; Du, Fang; Liu, Yang; Li, Li; Cai, Jing; Zhang, Guo-Feng; Xu, Xiao-Fei; Lin, Tian; Cheng, Hao-Ran; Liu, Xue-Dong; Xiong, Li-Ze; Zhao, Gang

    2013-11-01

    Vibroacoustic disease, a progressive and systemic disease, mainly involving the central nervous system, is caused by excessive exposure to low-frequency but high-intensity noise generated by various heavy transportations and machineries. Infrasound is a type of low-frequency noise. Our previous studies demonstrated that infrasound at a certain intensity caused neuronal injury in rats but the underlying mechanism(s) is still largely unknown. Here, we showed that glial cell-expressed TRPV4, a Ca(2+)-permeable mechanosensitive channel, mediated infrasound-induced neuronal injury. Among different frequencies and intensities, infrasound at 16 Hz and 130 dB impaired rat learning and memory abilities most severely after 7-14 days exposure, a time during which a prominent loss of hippocampal CA1 neurons was evident. Infrasound also induced significant astrocytic and microglial activation in hippocampal regions following 1- to 7-day exposure, prior to neuronal apoptosis. Moreover, pharmacological inhibition of glial activation in vivo protected against neuronal apoptosis. In vitro, activated glial cell-released proinflammatory cytokines IL-1β and TNF-α were found to be key factors for this neuronal apoptosis. Importantly, infrasound induced an increase in the expression level of TRPV4 both in vivo and in vitro. Knockdown of TRPV4 expression by siRNA or pharmacological inhibition of TRPV4 in cultured glial cells decreased the levels of IL-1β and TNF-α, attenuated neuronal apoptosis, and reduced TRPV4-mediated Ca(2+) influx and NF-κB nuclear translocation. Finally, using various antagonists we revealed that calmodulin and protein kinase C signaling pathways were involved in TRPV4-triggered NF-κB activation. Thus, our results provide the first evidence that glial cell-expressed TRPV4 is a potential key factor responsible for infrasound-induced neuronal impairment. PMID:24002225

  17. Lipopolysaccharide-induced epithelial monoamine oxidase mediates alveolar bone loss in a rat chronic wound model.

    PubMed

    Ekuni, Daisuke; Firth, James D; Nayer, Tarun; Tomofuji, Takaaki; Sanbe, Toshihiro; Irie, Koichiro; Yamamoto, Tatsuo; Oka, Takashi; Liu, Zhenzi; Vielkind, Juergen; Putnins, Edward E

    2009-10-01

    Reactive oxygen species (ROS) production is an antimicrobial response to pathogenic challenge that may, in the case of persistent infection, have deleterious effects on the tissue of origin. A rat periodontal disease model was used to study ROS-induced chronic epithelial inflammation and bone loss. Lipopolysaccharide (LPS) was applied for 8 weeks into the gingival sulcus, and histological analysis confirmed the onset of chronic disease. Junctional epithelium was collected from healthy and diseased animals using laser-capture microdissection, and expression microarray analysis was performed. Of 19,730 genes changed in disease, 42 were up-regulated >/=4-fold. Three of the top 10 LPS-induced genes, monoamine oxidase B (MAO/B) and flavin-containing monooxygenase 1 and 2, are implicated in ROS signaling. LPS-associated induction of the ROS mediator H(2)O(2), as well as MAO/B and tumor necrosis factor (TNF)-alpha levels were validated in the rat histological sections and a porcine junctional epithelial cell culture model. Topical MAO inhibitors significantly counteracted LPS-associated elevation of H(2)O(2) production and TNF-alpha expression in vivo and in vitro, inhibited disease-associated apical migration and proliferation of junctional epithelium and inhibited induced systemic H(2)O(2) levels and alveolar bone loss in vivo. These results suggest that LPS induces chronic wounds via elevated MAO/B-mediated increases in H(2)O(2) and TNF-alpha activity by epithelial cells and is further associated with more distant effects on systemic oxidative stress and alveolar bone loss. PMID:19779138

  18. Hypothalamic CaMKKβ mediates glucagon anorectic effect and its diet-induced resistance

    PubMed Central

    Quiñones, Mar; Al-Massadi, Omar; Gallego, Rosalía; Fernø, Johan; Diéguez, Carlos; López, Miguel; Nogueiras, Ruben

    2015-01-01

    Objective Glucagon receptor antagonists and humanized glucagon antibodies are currently studied as promising therapies for obesity and type II diabetes. Among its variety of actions, glucagon reduces food intake, but the molecular mechanisms mediating this effect as well as glucagon resistance are totally unknown. Methods Glucagon and adenoviral vectors were administered in specific hypothalamic nuclei of lean and diet-induced obese rats. The expression of neuropeptides controlling food intake was performed by in situ hybridization. The regulation of factors of the glucagon signaling pathway was assessed by western blot. Results The central injection of glucagon decreased feeding through a hypothalamic pathway involving protein kinase A (PKA)/Ca2+-calmodulin-dependent protein kinase kinase β (CaMKKβ)/AMP-activated protein kinase (AMPK)-dependent mechanism. More specifically, the central injection of glucagon increases PKA activity and reduces protein levels of CaMKKβ and its downstream target phosphorylated AMPK in the hypothalamic arcuate nucleus (ARC). Consistently, central glucagon significantly decreased AgRP expression. Inhibition of PKA and genetic activation of AMPK in the ARC blocked glucagon-induced anorexia in lean rats. Genetic down-regulation of glucagon receptors in the ARC stimulates fasting-induced hyperphagia. Although glucagon was unable to decrease food intake in DIO rats, glucagon sensitivity was restored after inactivation of CaMKKβ, specifically in the ARC. Thus, glucagon decreases food intake acutely via PKA/CaMKKβ/AMPK dependent pathways in the ARC, and CaMKKβ mediates its obesity-induced hypothalamic resistance. Conclusions This work reveals the molecular underpinnings by which glucagon controls feeding that may lead to a better understanding of disease states linked to anorexia and cachexia. PMID:26909312

  19. Mast cell mediators in citric acid-induced airway constriction of guinea pigs

    SciTech Connect

    Lin, C.-H.; Lai, Y.-L. . E-mail: tiger@ha.mc.ntu.edu.tw

    2005-08-15

    We demonstrated previously that mast cells play an important role in citric acid (CA)-induced airway constriction. In this study, we further investigated the underlying mediator(s) for this type of airway constriction. At first, to examine effects caused by blocking agents, 67 young Hartley guinea pigs were divided into 7 groups: saline + CA; methysergide (serotonin receptor antagonist) + CA; MK-886 (leukotriene synthesis inhibitor) + CA; mepyramine (histamine H{sub 1} receptor antagonist) + CA; indomethacin (cyclooxygenase inhibitor) + CA; cromolyn sodium (mast cell stabilizer) + CA; and compound 48/80 (mast cell degranulating agent) + CA. Then, we tested whether leukotriene C{sub 4} (LTC{sub 4}) or histamine enhances CA-induced airway constriction in compound 48/80-pretreated guinea pigs. We measured dynamic respiratory compliance (Crs) and forced expiratory volume in 0.1 s (FEV{sub 0.1}) during either baseline or recovery period. In addition, we detected histamine level, an index of pulmonary mast cell degranulation, in bronchoalveolar lavage (BAL) samples. Citric acid aerosol inhalation caused decreases in Crs and FEV{sub 0.1}, indicating airway constriction in the control group. This airway constriction was significantly attenuated by MK-886, mepyramine, cromolyn sodium, and compound 48/80, but not by either methysergide or indomethacin. Both LTC{sub 4} and histamine infusion significantly increased the magnitude of CA-induced airway constriction in compound 48/80-pretreated guinea pigs. Citric acid inhalation caused significant increase in histamine level in the BAL sample, which was significantly suppressed by compound 48/80. These results suggest that leukotrienes and histamine originating from mast cells play an important role in CA inhalation-induced noncholinergic airway constriction.

  20. Lycopene inhibits LPS-induced proinflammatory mediator inducible nitric oxide synthase in mouse macrophage cells.

    PubMed

    Rafi, Mohamed M; Yadav, Prem Narayan; Reyes, Marynell

    2007-01-01

    Lycopene is a fat-soluble red-orange carotenoid found primarily in tomatoes and tomato-derived products, including tomato sauce, tomato paste, and ketchup, and other dietary sources, including dried apricots, guava, watermelon, papaya, and pink grapefruit. In this study, we have demonstrated the molecular mechanism underlying the anti-inflammatory properties of lycopene using a mouse macrophage cell line (RAW 264.7). Treatment with lycopene (10 microM) inhibited lipopolysaccharide (LPS)-stimulated nitric oxide (NO) production (40% compared with the control). Western blotting and reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that lycopene treatment decreased LPS-induced inducible nitric oxide synthase (iNOS) protein and mRNA expression in RAW 264.7 cells, respectively. These results suggest that lycopene has anti-inflammatory activity by inhibiting iNOS proteins and mRNA expressions in mouse macrophage cell lines. Furthermore, cyclooxygenase-2 (COX-2) protein and mRNA expression were not affected by treatment with lycopene. PMID:17995901

  1. Sequence of arrival determines plant-mediated interactions between herbivores

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Summary 1. Induced changes in plant quality are important factors mediating indirect interactions between herbivores. Although the sequence of attack has been shown to influence plant responses, little is known about how it may affect the outcome of insect-plant-insect interactions. 2. We therefore...

  2. Mast cell chymase induces smooth muscle cell apoptosis by disrupting NF-{kappa}B-mediated survival signaling

    SciTech Connect

    Leskinen, Markus J.; Heikkilae, Hanna M.; Speer, Mei Y.; Hakala, Jukka K.; Laine, Mika; Kovanen, Petri T.; Lindstedt, Ken A. . E-mail: ken.lindstedt@wri.fi

    2006-05-01

    Chymase released from activated mast cells induces apoptosis of vascular smooth muscle cells (SMCs) in vitro by degrading the pericellular matrix component fibronectin, so causing disruption of focal adhesion complexes and Akt dephosphorylation, which are necessary for cell adhesion and survival. However, the molecular mechanisms of chymase-mediated apoptosis downstream of Akt have remained elusive. Here, we show by means of RT-PCR, Western blotting, EMSA, immunocytochemistry and confocal microscopy, that chymase induces SMC apoptosis by disrupting NF-{kappa}B-mediated survival signaling. Following chymase treatment, the translocation of active NF-{kappa}B/p65 to the nucleus was partly abolished and the amount of nuclear p65 was reduced. Pretreatment of SMCs with chymase also inhibited LPS- and IL-1{beta}-induced nuclear translocation of p65. The chymase-induced degradation of p65 was mediated by active caspases. Loss of NF-{kappa}B-mediated transactivation resulted in downregulation of bcl-2 mRNA and protein expression, leading to mitochondrial swelling and release of cytochrome c. The apoptotic process involved activation of both caspase 9 and caspase 8. The results reveal that, by disrupting the NF-{kappa}B-mediated survival-signaling pathway, activated chymase-secreting mast cells can mediate apoptosis of cultured arterial SMCs. Since activated mast cells colocalize with apoptotic SMCs in vulnerable areas of human atherosclerotic plaques, they may participate in the weakening and rupture of atherosclerotic plaques.

  3. Sorafenib induces apoptosis in HL60 cells by inhibiting Src kinase-mediated STAT3 phosphorylation.

    PubMed

    Zhao, Wei; Zhang, Tao; Qu, Bingqian; Wu, Xingxin; Zhu, Xu; Meng, Fanyu; Gu, Yanhong; Shu, Yongqian; Shen, Yan; Sun, Yang; Xu, Qiang

    2011-01-01

    Signal transducer and activator of transcription 3 (STAT3) is constitutively active in approximately 50% of acute myeloid leukemia (AML) cases and mediates multiple cellular processes including cell resistance to apoptosis. Inhibition of constitutively active STAT3 has been shown to induce AML cell apoptosis. Our aim was to ascertain if sorafenib, a multikinase inhibitor, may also inhibit STAT3 signaling and, therefore, be efficacious for AML. We found that sorafenib inhibited proliferation and induced apoptosis in human AML cell line (HL60) cells. In addition, sorafenib exposure reduced constitutive STAT3 phosphorylation in HL60 cells and repressed STAT3 DNA-binding activity and Mcl-1 and Bcl-2 expression. Similar results were obtained with the Src kinase inhibitor I, suggesting that sorafenib suppresses STAT3 phosphorylation by inhibiting Src-kinase activity. Furthermore, significant inhibition of Src kinase activity by sorafenib was observed in the kinase assay. In addition, Src could be co-immunoprecipitated with STAT3, and the phosphorylation of STAT3 was significantly inhibited by sorafenib only in cell lines in which phosphorylated Src is highly expressed. Taken together, our study indicates that sorafenib blocks Src kinase-mediated STAT3 phosphorylation and decreases the expression of apoptosis regulatory proteins Mcl-1 and Bcl-2, which are associated with increased apoptosis in HL60 cells. These findings provide a rationale for the treatment of human AML. PMID:20881478

  4. Toll-like receptor 4-mediated lymphocyte influx induces neonatal necrotizing enterocolitis.

    PubMed

    Egan, Charlotte E; Sodhi, Chhinder P; Good, Misty; Lin, Joyce; Jia, Hongpeng; Yamaguchi, Yukihiro; Lu, Peng; Ma, Congrong; Branca, Maria F; Weyandt, Samantha; Fulton, William B; Niño, Diego F; Prindle, Thomas; Ozolek, John A; Hackam, David J

    2016-02-01

    The nature and role of the intestinal leukocytes in necrotizing enterocolitis (NEC), a severe disease affecting premature infants, remain unknown. We now show that the intestine in mouse and human NEC is rich in lymphocytes that are required for NEC development, as recombination activating gene 1–deficient (Rag1–/–) mice were protected from NEC and transfer of intestinal lymphocytes from NEC mice into naive mice induced intestinal inflammation. The intestinal expression of the lipopolysaccharide receptor TLR4, which is higher in the premature compared with full-term human and mouse intestine, is required for lymphocyte influx through TLR4-mediated upregulation of CCR9/CCL25 signaling. TLR4 also mediates a STAT3-dependent polarization toward increased proinflammatory CD3+CD4+IL-17+ and reduced tolerogenic Foxp3+ Treg lymphocytes (Tregs). Th17 lymphocytes were required for NEC development, as inhibition of STAT3 or IL-17 receptor signaling attenuated NEC in mice, while IL-17 release impaired enterocyte tight junctions, increased enterocyte apoptosis, and reduced enterocyte proliferation, leading to NEC. Importantly, TLR4-dependent Th17 polarization could be reversed by the enteral administration of retinoic acid, which induced Tregs and decreased NEC severity. These findings identify an important role for proinflammatory lymphocytes in NEC development via intestinal epithelial TLR4 that could be reversed through dietary modification. PMID:26690704

  5. Rosiglitazone-mediated dendritic cells ameliorate collagen-induced arthritis in mice.

    PubMed

    Byun, Sei-Hee; Lee, Jun-Ho; Jung, Nam-Chul; Choi, Hyun-Ji; Song, Jie-Young; Seo, Han Geuk; Choi, Jinjung; Jung, Sang Youn; Kang, Sangjin; Choi, Yong-Soo; Chung, Ji Hyung; Lim, Dae-Seog

    2016-09-01

    Rosiglitazone is a selective ligand for peroxisome proliferator-activated receptor-gamma (PPAR-γ), which serves diverse biological functions. A number of autoimmune disease models have been used to examine the anti-inflammatory and immunosuppressive effects of tolerogenic dendritic cells (tDCs). The aim of the present study was to investigate whether rosiglitazone-mediated DC (Rosi-DC) therapy suppressed arthritis in a collagen-induced arthritis (CIA) mouse model. Rosi-DCs were generated by treating immature DCs with TNF-α, type II collagen, and rosiglitazone. CIA mice then received subcutaneously (s.c.) two injections of Rosi-DCs. The severity of arthritis was then assessed histopathologically. The phenotypes of the DC and regulatory T (Treg) cell populations in CIA mice were determined by flow cytometry and the effect of Rosi-DCs on the secretion of autoimmunity-inducing cytokines was examined by ELISA. Rosi-DCs expressed lower levels of DC-related surface markers than mature DCs. Histopathological examination revealed that the degree of inflammation in the paws of Rosi-DC-treated mice was much lower than that in the paws of PBS-treated CIA mice. Taken together, these results clearly show that rosiglitazone-mediated DCs ameliorate CIA, most likely via the induction of antigen-specific Treg cells. PMID:27208887

  6. Superoxide anions mediate veratridine-induced cytochrome c release and caspase activity in bovine chromaffin cells

    PubMed Central

    Jordán, Joaquín; Galindo, María F; Tornero, Daniel; Benavides, Amparo; González, Constancio; Agapito, María T; González-Garcia, Carmen; Ceña, Valentín

    2002-01-01

    Mitochondrial mechanisms involved in veratridine-induced chromaffin cell death have been explored. Exposure to veratridine (30 μM, 1 h) produces cytochrome c release to the cytoplasm that seems to be mediated by superoxide anions and that is blocked by cyclosporin A (10 μM), MnTBAP (10 nM), catalase (100 IU ml−1) and vitamin E (50 μM). Following veratridine treatment, there is an increase in caspase-like activity, blocked by vitamin E (50 μM) and the mitochondrial permeability transition pore blocker cyclosporin A (10 μM). Superoxide anions open the mitochondrial permeability transition pore in isolated mitochondria, an effect that is blocked by vitamin E (50 μM) and cyclosporin A (10 μM), but not by the Ca2+ uniporter blocker ruthenium red (5 μM). These results strongly suggest that under the stress situation caused by veratridine, superoxide anions become important regulators of mitochondrial function in chromaffin cells. Exposure of isolated bovine chromaffin mitochondria to Ca2+ results in mitochondrial swelling. This effect was prevented by ruthenium red (5 μM) and cyclosporin A (10 μM), while it was not modified by vitamin E (50 μM). Veratridine (30 μM, 1 h) markedly decreased total glutathione and GSH content in bovine chromaffin cells. In conclusion, superoxide anions seem to mediate veratridine-induced cytochrome c release, decrease in total glutathione, caspase activation and cell death in bovine chromaffin cells. PMID:12429571

  7. Sophoridinol derivative 05D induces tumor cells apoptosis by topoisomerase1-mediated DNA breakage

    PubMed Central

    Zhao, Wuli; Zhang, Caixia; Bi, Chongwen; Ye, Cheng; Song, Danqing; Liu, Xiujun; Shao, Rongguang

    2016-01-01

    Sophoridine is a quinolizidine natural product of Sophora alopecuroides and has been applied for treatment of malignant trophoblastic tumors. Although characterized by low toxicity, the limited-spectrum antitumor activity hinders its further applications. 05D, a derivative of sophoridine, exhibits a better anticancer activity on diverse cancer cells, including solid tumors, and hematologic malignancy. It could inhibit topoisomerase 1 (top1) activity by stabilizing DNA–top1 complex and induce mitochondria-mediated apoptosis by promoting DNA single- and double-strand breakage mediated by top1. Also, 05D induced HCT116 cells arrest at G1 phase by inactivating CDK2/CDK4–Rb–E2F and cyclinD1–CDK4–p21 checkpoint signal pathways. 05D suppressed the ataxia telangiectasia mutated (ATM) and ATM and Rad3-related (ATR) activation and decreased 53BP level, which contributed to DNA damage repair, suggesting that the novel compound 05D might be helpful to improve the antitumor activity of DNA damaging agent by repressing ATM and ATR activation and 53BP level. In addition, the priorities in molecular traits and druggability, such as a simple structure and formulation for oral administration, further prove 05D to be a promising targeting topoisomerase agent. PMID:27274276

  8. Toll-like receptor 4–mediated lymphocyte influx induces neonatal necrotizing enterocolitis

    PubMed Central

    Egan, Charlotte E.; Sodhi, Chhinder P.; Good, Misty; Lin, Joyce; Jia, Hongpeng; Yamaguchi, Yukihiro; Lu, Peng; Ma, Congrong; Branca, Maria F.; Weyandt, Samantha; Fulton, William B.; Niño, Diego F.; Prindle, Thomas; Ozolek, John A.; Hackam, David J.

    2015-01-01

    The nature and role of the intestinal leukocytes in necrotizing enterocolitis (NEC), a severe disease affecting premature infants, remain unknown. We now show that the intestine in mouse and human NEC is rich in lymphocytes that are required for NEC development, as recombination activating gene 1–deficient (Rag1–/–) mice were protected from NEC and transfer of intestinal lymphocytes from NEC mice into naive mice induced intestinal inflammation. The intestinal expression of the lipopolysaccharide receptor TLR4, which is higher in the premature compared with full-term human and mouse intestine, is required for lymphocyte influx through TLR4-mediated upregulation of CCR9/CCL25 signaling. TLR4 also mediates a STAT3-dependent polarization toward increased proinflammatory CD3+CD4+IL-17+ and reduced tolerogenic Foxp3+ Treg lymphocytes (Tregs). Th17 lymphocytes were required for NEC development, as inhibition of STAT3 or IL-17 receptor signaling attenuated NEC in mice, while IL-17 release impaired enterocyte tight junctions, increased enterocyte apoptosis, and reduced enterocyte proliferation, leading to NEC. Importantly, TLR4-dependent Th17 polarization could be reversed by the enteral administration of retinoic acid, which induced Tregs and decreased NEC severity. These findings identify an important role for proinflammatory lymphocytes in NEC development via intestinal epithelial TLR4 that could be reversed through dietary modification. PMID:26690704

  9. Plumbagin induces apoptosis in Her2-overexpressing breast cancer cells through the mitochondrial-mediated pathway.

    PubMed

    Kawiak, Anna; Zawacka-Pankau, Joanna; Lojkowska, Ewa

    2012-04-27

    Breast cancer is the leading cause of death-related cancers in women. Approximately 30% of breast cancers overexpress the Her2 oncogene, which is associated with a poor prognosis and increased resistance to chemotherapy. Plumbagin (1), a constituent of species in the plant genera Drosera and Plumbago, displays antineoplastic activity toward various cancers. The present study was aimed at determining the anticancer potential of 1 toward Her2-overexpressing breast cancer cells and defining the mode of cell death induced in these cells. The results showed that 1 exhibited high antiproliferative activity toward the Her2-overexpressing cell lines SKBR3 and BT474. The antiproliferative activity of 1 was associated with apoptosis-mediated cell death, as revealed by caspase activation and an increase in the sub-G1 fraction of the cell cycle. Compound 1 increased the levels of the proapoptotic Bcl-2 family of proteins and decreased the level of the antiapoptotic Bcl-2 protein in SKBR3 and BT474 cells. Thus, these findings indicate that 1 induces apoptosis in Her2-overexpressing breast cancers through the mitochondrial-mediated pathway and suggest its potential for further investigation for the treatment of Her2-overexpressing breast cancer. PMID:22512718

  10. Heme-induced Trypanosoma cruzi proliferation is mediated by CaM kinase II

    SciTech Connect

    Souza, C.F.; Carneiro, A.B.; Silveira, A.B.; Laranja, G.A.T.; Silva-Neto, M.A.C.; Costa, S.C. Goncalves da; Paes, M.C.

    2009-12-18

    Trypanosoma cruzi, the etiologic agent of Chagas disease, is transmitted through triatomine vectors during their blood-meal on vertebrate hosts. These hematophagous insects usually ingest approximately 10 mM of heme bound to hemoglobin in a single meal. Blood forms of the parasite are transformed into epimastigotes in the crop which initiates a few hours after parasite ingestion. In a previous work, we investigated the role of heme in parasite cell proliferation and showed that the addition of heme significantly increased parasite proliferation in a dose-dependent manner . To investigate whether the heme effect is mediated by protein kinase signalling pathways, parasite proliferation was evaluated in the presence of several protein kinase (PK) inhibitors. We found that only KN-93, a classical inhibitor of calcium-calmodulin-dependent kinases (CaMKs), blocked heme-induced cell proliferation. KN-92, an inactive analogue of KN-93, was not able to block this effect. A T. cruzi CaMKII homologue is most likely the main enzyme involved in this process since parasite proliferation was also blocked when Myr-AIP, an inhibitory peptide for mammalian CaMKII, was included in the cell proliferation assay. Moreover, CaMK activity increased in parasite cells with the addition of heme as shown by immunological and biochemical assays. In conclusion, the present results are the first strong indications that CaMKII is involved in the heme-induced cell signalling pathway that mediates parasite proliferation.

  11. EMT phenotype is induced by increased Src kinase activity via Src-mediated caspase-8 phosphorylation.

    PubMed

    Zhao, Yang; Li, XiaoJun; Sun, XiangFei; Zhang, YunFeng; Ren, Hong

    2012-01-01

    Caspase-8 governs multiple cell responses to the microenvironmental cues. However, its integration of "death-life" signalings remains elusive. In our study, the role of caspase-8-Src is well-established as a promoter for migration or metastasis in Casp8(+)Src(+) A549/H226 cells in vivo and in vitro. In particular for nude mice models, mice implanted with Casp8(+)Src(+) A459/H226 cells remarkably increased spontaneous tumor metastatic burden with a significant survival disadvantage. Additionally, we detect that Src-mediated caspase-8 phosphorylation stimulates Src phosphorylation at Tyr-416 via the linkage of Src SH2 domain with phosph-Tyr-380 site of caspase-8. In turn, activated Src can efficiently induce epithelial-mesenchymal transition (EMT) phenotypic features to promote tumor cells metastasis. Surprisingly, RXDLL motif deletion in the DEDa of caspase-8 attenuates tumor cell migration or metastasis via impairing the recruitment of caspase-8 into the cellular periphery where activated Src is subject to caspase-8 phosphorylation. Together, a simple model is that the peripherization of caspase-8 is well-poised to facilitate Src-mediated caspase-8 phosphrylation at Tyr-380, then binding of phospho-Tyr380 of caspase-8 to Src SH2 domain may maintain Src in an active conformation to induce EMT phenotype, a key step toward cancer metastasis. PMID:22508042

  12. GLI3-dependent repression of DR4 mediates hedgehog antagonism of TRAIL-induced apoptosis.

    PubMed

    Kurita, S; Mott, J L; Almada, L L; Bronk, S F; Werneburg, N W; Sun, S-Y; Roberts, L R; Fernandez-Zapico, M E; Gores, G J

    2010-08-26

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through its cognate receptors death receptor 4 (DR4) and death receptor 5 (DR5), preferentially in malignant cells. However, many malignant cells remain resistant to TRAIL cytotoxicity by poorly characterized mechanisms. Here, using cholangiocarcinoma cells, as a model for TRAIL resistance, we identified a role for the oncogenic Hedgehog (Hh)-GLI pathway in the regulation of TRAIL cytotoxicity. Blockade of Hh using pharmacological and genetic tools sensitizes the cells to TRAIL cytotoxicity. Restoration of apoptosis sensitivity coincided with upregulation of DR4 expression, while expression of other death effector proteins remained unaltered. Knockdown of DR4 mimics Hh-mediated resistance to TRAIL cytotoxicity. Hh regulates the expression of DR4 by modulating the activity of its promoter. Luciferase, chromatin immunoprecipitation and expression assays show that the transcription factor GLI3 binds to the DR4 promoter and Hh requires an intact GLI3-repression activity to silence DR4 expression. Finally, small interfering RNA (siRNA)-targeted knockdown of GLI3, but not GLI1 or GLI2, restores DR4 expression and TRAIL sensitivity, indicating that the Hh effect is exclusively mediated by this transcription factor. In conclusion, these data provide evidence of a regulatory mechanism, which modulates TRAIL signaling in cancer cells and suggest new therapeutic approaches for TRAIL-resistant neoplasms. PMID:20562908

  13. GLI3-dependent repression of DR4 mediates hedgehog antagonism of TRAIL-induced apoptosis

    PubMed Central

    Kurita, S; Mott, JL; Almada, LL; Bronk, SF; Werneburg, NW; Sun, S-Y; Roberts, LR; Fernandez-Zapico, ME; Gores, GJ

    2010-01-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis through its cognate receptors death receptor 4 (DR4) and death receptor 5 (DR5), preferentially in malignant cells. However, many malignant cells remain resistant to TRAIL cytotoxicity by poorly characterized mechanisms. Here, using cholangiocarcinoma cells, as a model for TRAIL resistance, we identified a role for the oncogenic Hedgehog (Hh)-GLI pathway in the regulation of TRAIL cytotoxicity. Blockade of Hh using pharmacological and genetic tools sensitizes the cells to TRAIL cytotoxicity. Restoration of apoptosis sensitivity coincided with upregulation of DR4 expression, while expression of other death effector proteins remained unaltered. Knockdown of DR4 mimics Hh-mediated resistance to TRAIL cytotoxicity. Hh regulates the expression of DR4 by modulating the activity of its promoter. Luciferase, chromatin immunoprecipitation and expression assays show that the transcription factor GLI3 binds to the DR4 promoter and Hh requires an intact GLI3-repression activity to silence DR4 expression. Finally, small interfering RNA (siRNA)-targeted knockdown of GLI3, but not GLI1 or GLI2, restores DR4 expression and TRAIL sensitivity, indicating that the Hh effect is exclusively mediated by this transcription factor. In conclusion, these data provide evidence of a regulatory mechanism, which modulates TRAIL signaling in cancer cells and suggest new therapeutic approaches for TRAIL-resistant neoplasms. PMID:20562908

  14. NADPH oxidase mediates glucolipotoxicity-induced beta cell dysfunction--clinical implications.

    PubMed

    McCarty, Mark F; Barroso-Aranda, Jorge; Contreras, Francisco

    2010-03-01

    An impairment of glucose-stimulated insulin secretion--reflecting decreased glucokinase expression--and a moderate decrease in beta cell mass attributable to increased apoptosis, constitute the key features of beta cell failure in type 2 diabetes. Oxidative stress, provoked by prolonged exposure to excessive levels of glucose and/or fatty acids (glucolipotoxicity), appears to be a key mediator of these defects. Oxidant-provoked JNK activation induces nuclear export of the PDX-1 transcription factor, required for expression of glucokinase and other beta cell proteins. Conversely, increases in cAMP induced by incretin hormones promote the nuclear importation of PDX-1, counteracting the diabetogenic impact of oxidant stress; this may explain the utility of measures that slow dietary carbohydrate absorption for diabetes prevention. The ability of oxidative stress to boost apoptosis in beta cells is poorly understood, but may also entail JNK activation. Recent work establishes a phagocyte-type NADPH oxidase as the chief source of glucotoxicity-mediated oxidative stress in beta cells. Since bilirubin is now known to function physiologically as an inhibitor of NADPH oxidase, and phycocyanobilin (PCB) derived from spirulina likewise can inhibit this enzyme complex, supplemental PCB may have utility in the prevention and control of diabetes, and Gilbert syndrome, associated with chronically elevated free bilirubin, may be associated with decreased diabetes risk. PMID:19576699

  15. NMDA-induced accumulation of Shank at the postsynaptic density is mediated by CaMKII

    SciTech Connect

    Tao-Cheng, Jung-Hwa; Yang, Yijung; Bayer, K. Ulrich; Reese, Thomas S.; Dosemeci, Ayse

    2014-07-18

    Highlights: • NMDA-induces accumulation of Shank at the postsynaptic density. • Shank accumulation is preferential to the distal region of the postsynaptic density. • Shank accumulation is mediated by CaMKII. - Abstract: Shank is a specialized scaffold protein present in high abundance at the postsynaptic density (PSD). Using pre-embedding immunogold electron microscopy on cultured hippocampal neurons, we had previously demonstrated further accumulation of Shank at the PSD under excitatory conditions. Here, using the same experimental protocol, we demonstrate that a cell permeable CaMKII inhibitor, tatCN21, blocks NMDA-induced accumulation of Shank at the PSD. Furthermore we show that NMDA application changes the distribution pattern of Shank at the PSD, promoting a 7–10 nm shift in the median distance of Shank labels away from the postsynaptic membrane. Inhibition of CaMKII with tatCN21 also blocks this shift in the distribution of Shank. Altogether these results imply that upon activation of NMDA receptors, CaMKII mediates accumulation of Shank, preferentially at the distal regions of the PSD complex extending toward the cytoplasm.

  16. Lung-derived soluble mediators are pathogenic in ventilator-induced lung injury.

    PubMed

    Jaecklin, Thomas; Engelberts, Doreen; Otulakowski, Gail; O'Brodovich, Hugh; Post, Martin; Kavanagh, Brian P

    2011-04-01

    Ventilator-induced lung injury (VILI) due to high tidal volume (V(T)) is associated with increased levels of circulating factors that may contribute to, or be markers of, injury. This study investigated if exclusively lung-derived circulating factors produced during high V(T) ventilation can cause or worsen VILI. In isolated perfused mouse lungs, recirculation of perfusate worsened injury (compliance impairment, microvascular permeability, edema) induced by high V(T). Perfusate collected from lungs ventilated with high V(T) and used to perfuse lungs ventilated with low V(T) caused similar compliance impairment and permeability and caused a dose-dependent decrease in transepithelial electrical resistance (TER) across rat distal lung epithelial monolayers. Circulating soluble factors derived from the isolated lung thus contributed to VILI and had deleterious effects on the lung epithelial barrier. These data demonstrate transferability of an injury initially caused exclusively by mechanical ventilation and provides novel evidence for the biotrauma hypothesis in VILI. Mediators of the TER decrease were heat-sensitive, transferable via Folch extraction, and (following ultrafiltration, 3 kDa) comprised both smaller and larger molecules. Although several classes of candidate mediators, including protein cytokines (e.g., tumor necrosis factor-α, interleukin-6, macrophage inflammation protein-1α) and lipids (e.g., eicosanoids, ceramides, sphingolipids), have been implicated in VILI, only prostanoids accumulated in the perfusate in a pattern consistent with a pathogenic role, yet cyclooxygenase inhibition did not protect against injury. Although no single class of factor appears solely responsible for the decrease in barrier function, the current data implicate lipid-soluble protein-bound molecules as not just markers but pathogenic mediators in VILI. PMID:21239530

  17. Apoptosis induced by granzyme B-glycosaminoglycan complexes: implications for granule-mediated apoptosis in vivo.

    PubMed

    Galvin, J P; Spaeny-Dekking, L H; Wang, B; Seth, P; Hack, C E; Froelich, C J

    1999-05-01

    Lymphocyte granule-mediated apoptosis occurs by perforin-mediated intracellular delivery of granule-associated serine proteases (granzymes). A granule-associated proteoglycan, namely serglycin, that contains chondroitin 4-sulfate (CS) glycosaminoglycans is present in the granules of cytotoxic cells. Serglycin acts as scaffold for packaging the positively charged granzymes and probably chaperones the proteases secreted extracellularly. To learn how the interaction of granzyme B (GrB) with serglycin might influence the apoptotic potential of this proteases, we have evaluated a model system where desalted CS is combined with isolated human granzyme. CS-GrB complexes were very stable, remaining undissociated in salt concentrations upwards to 500 mM (pH 7.4). On the basis of a capture enzyme immunoassay that accurately detects GrB, equivalent amounts of active free and CS-GrB, delivered by perforin or adenovirus, efficiently induced apoptosis in Jurkat cells and produced a similar time-dependent increase in caspase-3-like activity. CS-GrB processed isolated caspases-3 and -7 less efficiently than free granzyme. However, when added to cytosolic extracts, rates of processing were nearly equivalent for the two forms, suggesting cationic GrB may nonspecifically bind cytosolic proteins, leading to reduce proteolytic activity. Finally, GrB was found to be exocytosed from lymphocyte-activated killer cells as a neutral, high macromolecular weight complex, which possessed apoptotic activity. Collectively, the results indicate that neutral, high m.w. GrB has the capacity to induce cell death and will be useful to study the mechanism of cytotoxic cell-mediated apoptosis in vitro. PMID:10228010

  18. Cell adhesion molecules mediate radiation-induced leukocyte adhesion to the vascular endothelium.

    PubMed

    Hallahan, D; Kuchibhotla, J; Wyble, C

    1996-11-15

    The predominant early histological changes in irradiated tissues are edema and leukocyte infiltration. Cell adhesion molecules (CAMs) are required for the extravasation of leukocytes from the circulation. To study the role of CAMs in the pathogenesis of radiation-mediated inflammation, we quantified the expression of P-selectin, E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 glycoproteins on the surface of irradiated human endothelial cells. We found that E-selectin and ICAM-1 expression increased after irradiation, whereas there was no increased expression of other cytokine-inducible adhesion molecules (P-selectin or vascular cell adhesion molecule-1). We found a dose- and time-dependent increase in radiation-induced expression of both E-selectin and ICAM-1. Furthermore, the threshold dose for E-selectin expression was 1 Gy, whereas the threshold dose for ICAM-1 synthesis was 5 Gy of X-rays. Northern blot analysis of RNA from irradiated endothelial cells demonstrated that ICAM-1 is expressed at 3-6 h following irradiation. No de novo protein synthesis was required for increased ICAM-1 mRNA expression. The 1.1-kb segment of the 5' untranslated region of the ICAM-1 gene was sufficient for X-ray induction of chloramphenicol acetyltransferase reporter gene expression. We measured whether ICAM-1 mediates adhesion of leukocyte to the irradiated endothelium and found that leukocyte adhesion occurred concurrently with ICAM-1 induction. Radiation-mediated leukocyte adhesion was prevented by anti-ICAM-1 blocking antibodies. These data indicate that ICAM-1 participates in the inflammatory response to ionizing radiation. Moreover, radiation induction of these CAMs occurs in the absence of tumor necrosis factor and interleukin 1 production. PMID:8912850

  19. Leukotriene D4-induced Caco-2 cell proliferation is mediated by prostaglandin E2 synthesis

    PubMed Central

    Cabral, Marisol; Martín-Venegas, Raquel; Moreno, Juan J

    2015-01-01

    Leukotriene D4 (LTD4) is a pro-inflammatory mediator formed from arachidonic acid through the action of 5-lipoxygenase (5-LOX). Its biological effects are mediated by at least two G-coupled plasmatic cysteinyl LT receptors (CysLT1-2R). It has been reported an upregulation of the 5-LOX pathway in tumor tissue unlike in normal colon mucosa. Colon tumors generally have an increased expression of CysLT1R and colon cancer patients with high expression levels of CysLT1R have poor prognosis. We previously observed that the cyclooxygenase pathway is involved in the control of intestinal epithelial cancer cell growth through PGE2 production. The aim of this study was therefore to assess the effect of LTD4 binding with CysLT1R on Caco-2 cell growth. We note a number of key findings from this research. We observed that at a concentration similar to that found under inflammatory conditions, LTD4 was able to induce Caco-2 cell proliferation and DNA synthesis. Moreover, with the use of a specific receptor antagonist this study has demonstrated that the effect of LTD4 is a result of its interaction with CystLT1R. We also note the possible participation of the PLC-IP3-Ca2+/DAG-PKC signaling pathways in cytosolic PLA2 and [3H]AA release induced by LTD4-CystLT1R interaction. Finally, we found that the resulting activation of the AA cascade and the production of PGE2 eicosanoid could be related to the activation of cell signaling pathways such as ERK and CREB. These findings will help facilitate our understanding of how inflammatory mediators can affect the survival and dissemination of intestinal carcinoma cells. PMID:26216432

  20. Interleukin-1β mediates macrophage-induced impairment of insulin signaling in human primary adipocytes

    PubMed Central

    Gao, Dan; Madi, Mohamed; Ding, Cherlyn; Fok, Matthew; Steele, Thomas; Ford, Christopher; Hunter, Leif

    2014-01-01

    Adipose tissue expansion during obesity is associated with increased macrophage infiltration. Macrophage-derived factors significantly alter adipocyte function, inducing inflammatory responses and decreasing insulin sensitivity. Identification of the major factors that mediate detrimental effects of macrophages on adipocytes may offer potential therapeutic targets. IL-1β, a proinflammatory cytokine, is suggested to be involved in the development of insulin resistance. This study investigated the role of IL-1β in macrophage-adipocyte cross-talk, which affects insulin signaling in human adipocytes. Using macrophage-conditioned (MC) medium and human primary adipocytes, we examined the effect of IL-1β antagonism on the insulin signaling pathway. Gene expression profile and protein abundance of insulin signaling molecules were determined, as was the production of proinflammatory cytokine/chemokines. We also examined whether IL-1β mediates MC medium-induced alteration in adipocyte lipid storage. MC medium and IL-1β significantly reduced gene expression and protein abundance of insulin signaling molecules, including insulin receptor substrate-1, phosphoinositide 3-kinase p85α, and glucose transporter 4 and phosphorylation of Akt. In contrast, the expression and release of the proinflammatory markers, including IL-6, IL-8, monocyte chemotactic protein-1, and chemokine (C-C motif) ligand 5 by adipocytes were markedly increased. These changes were significantly reduced by blocking IL-1β activity, its receptor binding, or its production by macrophages. MC medium-inhibited expression of the adipogenic factors and -stimulated lipolysis was also blunted with IL-1β neutralization. We conclude that IL-1β mediates, at least in part, the effect of macrophages on insulin signaling and proinflammatory response in human adipocytes. Blocking IL-1β could be beneficial for preventing obesity-associated insulin resistance and inflammation in human adipose tissue. PMID:24918199

  1. Hypoxia-inducible Factor-dependent Production of Profibrotic Mediators by Hypoxic Hepatocytes

    PubMed Central

    Copple, Bryan L.; Bustamante, Juan J.; Welch, Timothy P.; Kim, Nam Deuk; Moon, Jeon-OK

    2011-01-01

    Background/Aims During the development of liver fibrosis, mediators are produced that stimulate cells in the liver to differentiate into myofibroblasts and to produce collagen. Recent studies demonstrated that the transcription factor, hypoxia-inducible factor-1α (HIF-1α), is critical for upregulation of profibrotic mediators, such as platelet-derived growth factor-A (PDGF-A), PDGF-B, and plasminogen activator inhibitor-1 (PAI-1) in the liver during the development of fibrosis. What remains unknown is the cell type-specific regulation of these genes by HIF-1α in liver cell types. Accordingly, the hypothesis was tested that HIF-1α is activated in hypoxic hepatocytes and regulates production of profibrotic mediators by these cells. Methods In this study, hepatocytes were isolated from the livers of control and HIF-1α or HIF-1β-Deficient mice and exposed to hypoxia. Results Exposure of primary mouse hepatocytes to 1% oxygen stimulated nuclear accumulation of HIF-1α and upregulated PAI-1, vascular endothelial cell growth factor, and the vasoactive peptides adrenomedullin-1 (ADM-1) and ADM-2. In contrast, levels of PDGF-A and PDGF-B mRNAs were unaffected in these cells by hypoxia. Exposure of HIF-1α-Deficient hepatocytes to 1% oxygen only partially prevented upregulation of these genes, suggesting that other hypoxia-regulated transcription factors, such as HIF-2α, may also regulate these genes. In support of this, HIF-2α was activated in hypoxic hepatocytes, and exposure of HIF-1β-Deficient hepatocytes to 1% oxygen completely prevented upregulation PAI-1, VEGF, and ADM-1, suggesting that HIF-2α may also contribute to upregulation of these genes in hypoxic hepatocytes. Conclusions Collectively, our results suggest that HIFs may be important regulators of profibrotic and vasoactive mediators by hypoxic hepatocytes. PMID:19302442

  2. A novel mechanism for the pyruvate protection against zinc-induced cytotoxicity: mediation by the chelating effect of citrate and isocitrate.

    PubMed

    Sul, Jee-Won; Kim, Tae-Youn; Yoo, Hyun Ju; Kim, Jean; Suh, Young-Ah; Hwang, Jung Jin; Koh, Jae-Young

    2016-08-01

    Intracellular accumulation of free zinc contributes to neuronal death in brain injuries such as ischemia and epilepsy. Pyruvate, a glucose metabolite, has been shown to block zinc neurotoxicity. However, it is largely unknown how pyruvate shows such a selective and remarkable protective effect. In this study, we sought to find a plausible mechanism of pyruvate protection against zinc toxicity. Pyruvate almost completely blocked cortical neuronal death induced by zinc, yet showed no protective effects against death induced by calcium (ionomycin, NMDA) or ferrous iron. Of the TCA cycle intermediates, citrate, isocitrate, and to a lesser extent oxaloacetate, protected against zinc toxicity. We then noted with LC-MS/MS assay that exposure to pyruvate, and to a lesser degree oxaloacetate, increased levels of citrate and isocitrate, which are known zinc chelators. While pyruvate added only during zinc exposure did not reduce zinc toxicity, citrate and isocitrate added only during zinc exposure, as did extracellular zinc chelator CaEDTA, completely blocked it. Furthermore, addition of pyruvate after zinc exposure substantially reduced intracellular zinc levels. Our results suggest that the remarkable protective effect of pyruvate against zinc cytotoxicity may be mediated indirectly by the accumulation of intracellular citrate and isocitrate, which act as intracellular zinc chelators. PMID:27515054

  3. Chloroquine-induced scratching is mediated by NO/cGMP pathway in mice.

    PubMed

    Foroutan, Arash; Haddadi, Nazgol Sadat; Ostadhadi, Sattar; Sistany, Narges; Dehpour, Ahmad Reza

    2015-07-01

    Chloroquine (CQ), a 4-aminoquinoline drug, has long been used in the treatment and prevention of malaria. However its side effect generalized pruritus contributes to treatment failures, and consequently results in the development of chloroquine resistant strains of Plasmodium falciparum. It was proposed that the administration of CQ correlated with increase in nitric oxide (NO) production. Nitric oxide is involved in some pruritic disorders such as atopic dermatitis, psoriasis and scratching behavior evoked by pruritogens like substance P. Therefore, the aim of this study was to investigate the involvement of NO/cGMP pathway in CQ-induced scratching in mice. Scratching behaviors were recorded by a camera after intradermal (ID) injection of CQ in the shaved rostral back of the mice. The results obtained show that CQ elicited scratching in a dose-dependent manner with a peak effective dose of 400μg/site. Injection of non-specific NOS inhibitor, N-nitro-l-arginine methyl ester or neuronal NOS selective inhibitor and 7-nitroindazole, reduced CQ-induced scratching significantly. On the other hand, administration of aminoguanidine as inducible NOS inhibitor has no inhibitory effect on this behavior. Also, injection of l-arginine as a precursor of NO significantly increased this response. Conversely, accumulation of cGMP by sildenafil as a selective phosphodiesterase type 5 inhibitor, potentiated the scratching behavior by CQ. This study therefore shows that CQ-induced scratching behavior is mediated by the NO/cGMP pathway. PMID:25957523

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

    PubMed

    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

  5. P2Y6 Receptor-Mediated Microglial Phagocytosis in Radiation-Induced Brain Injury.

    PubMed

    Xu, Yongteng; Hu, Weihan; Liu, Yimin; Xu, Pengfei; Li, Zichen; Wu, Rong; Shi, Xiaolei; Tang, Yamei

    2016-08-01

    Microglia are the resident immune cells and the professional phagocytic cells of the CNS, showing a multitude of cellular responses after activation. However, how microglial phagocytosis changes and whether it is involved in radiation-induced brain injury remain unknown. In the current study, we found that microglia were activated and microglial phagocytosis was increased by radiation exposure both in cultured microglia in vitro and in mice in vivo. Radiation increased the protein expression of the purinergic receptor P2Y6 receptor (P2Y6R) located on microglia. The selective P2Y6 receptor antagonist MRS2578 suppressed microglial phagocytosis after radiation exposure. Inhibition of microglial phagocytosis increased inhibitory factor Nogo-A and exacerbated radiation-induced neuronal apoptosis and demyelination. We also found that the levels of protein expression for phosphorylated Ras-related C3 botulinum toxin substrate 1 (Rac1) and myosin light chain kinase (MLCK) were elevated, indicating that radiation exposure activated Rac1 and MLCK. The Rac1 inhibitor NSC23766 suppressed expression of MLCK, indicating that the Rac1-MLCK pathway was involved in microglial phagocytosis. Taken together, these findings suggest that the P2Y6 receptor plays a critical role in mediating microglial phagocytosis in radiation-induced brain injury, which might be a potential strategy for therapeutic intervention to alleviate radiation-induced brain injury. PMID:26099306

  6. NK Cells and γδ T Cells Mediate Resistance to Polyomavirus–Induced Tumors

    PubMed Central

    Mishra, Rabinarayan; Chen, Alex T.; Welsh, Raymond M.; Szomolanyi-Tsuda, Eva

    2010-01-01

    NK and γδ T cells can eliminate tumor cells in many experimental models, but their effect on the development of tumors caused by virus infections in vivo is not known. Polyomavirus (PyV) induces tumors in neonatally infected mice of susceptible strains and in adult mice with certain immune deficiencies, and CD8+ αβ T cells are regarded as the main effectors in anti-tumor immunity. Here we report that adult TCRβ knockout (KO) mice that lack αβ but have γδ T cells remain tumor-free after PyV infection, whereas TCRβ×δ KO mice that lack all T cells develop tumors. In addition, E26 mice, which lack NK and T cells, develop the tumors earlier than TCRβ×δ KO mice. These observations implicate γδ T and NK cells in the resistance to PyV-induced tumors. Cell lines established from PyV-induced tumors activate NK and γδ T cells both in culture and in vivo and express Rae-1, an NKG2D ligand. Moreover, these PyV tumor cells are killed by NK cells in vitro, and this cytotoxicity is prevented by treatment with NKG2D-blocking antibodies. Our findings demonstrate a protective role for NK and γδ T cells against naturally occurring virus-induced tumors and suggest the involvement of NKG2D-mediated mechanisms. PMID:20523894

  7. Diosgenin inhibits IL-1β-induced expression of inflammatory mediators in human osteoarthritis chondrocytes.

    PubMed

    Wang, Leisheng; Ma, Tian; Zheng, Yanpin; Lv, Shiqiao; Li, Yu; Liu, Shaoxian

    2015-01-01

    It is well known that the inflammatory cytokines play important roles in osteoarthritis (OA). Diosgenin is a steroidal saponin found in several plants including Solanum and Dioscorea species and possesses diverse biological activities including anti-inflammatory properties. However, the role of diosgenin in inflammatory responses in OA chondrocytes is still unclear. Therefore, in this study, we investigated the anti-inflammatory properties of diosgenin in human OA chondrocytes. We found that diosgenin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) induced by interleukin-1-beta (IL-1β). Diosgenin significantly inhibited the IL-1β-stimulated expression of metalloproteinase-3 (MMP-3), MMP-13, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in human OA chondrocytes. In addition, diosgenin suppressed the degradation of IκB-α in IL-1β-induced human OA chondrocytes. Taken together, this study showed that diosgenin can effectively inhibit the IL-1β-induced expression of inflammatory mediators, suggesting that diosgenin may be a potential agent in the treatment of OA. PMID:26191174

  8. Diosgenin inhibits IL-1β-induced expression of inflammatory mediators in human osteoarthritis chondrocytes

    PubMed Central

    Wang, Leisheng; Ma, Tian; Zheng, Yanpin; Lv, Shiqiao; Li, Yu; Liu, Shaoxian

    2015-01-01

    It is well known that the inflammatory cytokines play important roles in osteoarthritis (OA). Diosgenin is a steroidal saponin found in several plants including Solanum and Dioscorea species and possesses diverse biological activities including anti-inflammatory properties. However, the role of diosgenin in inflammatory responses in OA chondrocytes is still unclear. Therefore, in this study, we investigated the anti-inflammatory properties of diosgenin in human OA chondrocytes. We found that diosgenin inhibited the production of nitric oxide (NO) and prostaglandin E2 (PGE2) induced by interleukin-1-beta (IL-1β). Diosgenin significantly inhibited the IL-1β-stimulated expression of metalloproteinase-3 (MMP-3), MMP-13, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in human OA chondrocytes. In addition, diosgenin suppressed the degradation of IκB-α in IL-1β-induced human OA chondrocytes. Taken together, this study showed that diosgenin can effectively inhibit the IL-1β-induced expression of inflammatory mediators, suggesting that diosgenin may be a potential agent in the treatment of OA. PMID:26191174

  9. Stress-induced early flowering is mediated by miR169 in Arabidopsis thaliana.

    PubMed

    Xu, Miao Yun; Zhang, Lan; Li, Wei Wei; Hu, Xiao Long; Wang, Ming-Bo; Fan, Yun Liu; Zhang, Chun Yi; Wang, Lei

    2014-01-01

    Plants interact with their environment and they often flower earlier under stress conditions, but how such stress-induced flowering is regulated remains poorly understood. Here evidence is presented that the miR169 family plays a key role in stress-induced flowering in plants. The microRNA (miRNA) miR169 family members are up-regulated in Arabidopsis, maize, and soybean under abiotic stresses. Overexpression of miR169d in Arabidopsis results in early flowering, and overexpression of the miR169d target gene, AtNF-YA2, especially a miR169d-resistant version of AtNF-YA2, results in late flowering. The results suggest that the miR169 family regulates stress-induced flowering by repressing the AtNF-YA transcription factor, which in turn reduces the expression of FLOWERING LOCUS C (FLC), allowing for the expression of FLC target genes such as FLOWERING LOCUS T (FT) and LEAFY (LFY) to promote flowering. It was shown that the expression of genes or miRNAs involved in the other flowering pathways, namely the photoperiod (CO), ambient temperature (SVP), ageing (miR156), and gibberelin (SOC1) pathways, was not affected in miR169d-overexpressing plants, suggesting that stress-induced early flowering is a novel signalling pathway mediated by miR169. PMID:24336445

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

    NASA Astrophysics Data System (ADS)

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

    2010-02-01

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

  11. Fungal metabolic plasticity and sexual development mediate induced resistance to arthropod fungivory.

    PubMed

    Döll, Katharina; Chatterjee, Subhankar; Scheu, Stefan; Karlovsky, Petr; Rohlfs, Marko

    2013-11-22

    Prey organisms do not tolerate predator attack passively but react with a multitude of inducible defensive strategies. Although inducible defence strategies are well known in plants attacked by herbivorous insects, induced resistance of fungi against fungivorous animals is largely unknown. Resistance to fungivory is thought to be mediated by chemical properties of fungal tissue, i.e. by production of toxic secondary metabolites. However, whether fungi change their secondary metabolite composition to increase resistance against arthropod fungivory is unknown. We demonstrate that grazing by a soil arthropod, Folsomia candida, on the filamentous fungus Aspergillus nidulans induces a phenotype that repels future fungivores and retards fungivore growth. Arthropod-exposed colonies produced significantly higher amounts of toxic secondary metabolites and invested more in sexual reproduction relative to unchallenged fungi. Compared with vegetative tissue and asexual conidiospores, sexual fruiting bodies turned out to be highly resistant against fungivory in facultative sexual A. nidulans. This indicates that fungivore grazing triggers co-regulated allocation of resources to sexual reproduction and chemical defence in A. nidulans. Plastic investment in facultative sex and chemical defence may have evolved as a fungal strategy to escape from predation. PMID:24068353

  12. Reactive oxygen species mediates homocysteine-induced mitochondrial biogenesis in human endothelial cells: Modulation by antioxidants

    SciTech Connect

    Perez-de-Arce, Karen; Foncea, Rocio . E-mail: rfoncea@med.puc.cl; Leighton, Federico

    2005-12-16

    It has been proposed that homocysteine (Hcy)-induces endothelial dysfunction and atherosclerosis by generation of reactive oxygen species (ROS). A previous report has shown that Hcy promotes mitochondrial damage. Considering that oxidative stress can affect mitochondrial biogenesis, we hypothesized that Hcy-induced ROS in endothelial cells may lead to increased mitochondrial biogenesis. We found that Hcy-induced ROS (1.85-fold), leading to a NF-{kappa}B activation and increase the formation of 3-nitrotyrosine. Furthermore, expression of the mitochondrial biogenesis factors, nuclear respiratory factor-1 and mitochondrial transcription factor A, was significantly elevated in Hcy-treated cells. These changes were accompanied by increase in mitochondrial mass and higher mRNA and protein expression of the subunit III of cytochrome c oxidase. These effects were significantly prevented by pretreatment with the antioxidants, catechin and trolox. Taken together, our results suggest that ROS is an important mediator of mitochondrial biogenesis induced by Hcy, and that modulation of oxidative stress by antioxidants may protect against the adverse vascular effects of Hcy.

  13. Carotid Body Chemoreflex Mediates Intermittent Hypoxia-Induced Oxidative Stress in the Adrenal Medulla

    PubMed Central

    Kumar, Ganesh K.; Peng, Ying-Jie; Nanduri, Jayasri; Prabhakar, Nanduri R.

    2016-01-01

    Intermittent hypoxia (IH) increases reactive oxygen species generation resulting in oxidative stress in the adrenal medulla (AM), a major end-organ of the sympathetic nervous system which facilitates catecholamine secretion by hypoxia. Here, we show that carotid body chemoreflex contributes to IH-induced oxidative stress in the AM. Carotid bodies were ablated by cryocoagulation of glomus cells, the putative O2 sensing cells. Carotid body ablated (CBA) and control rats were exposed to IH and the redox state of the AM was assessed biochemically. We found that IH raised reactive oxygen species levels along with an increase in NADPH oxidase (Nox), a pro-oxidant enzyme and a decrease in superoxide dismutase-2 (SOD2), an anti-oxidant enzyme. Further, IH increased hypoxia-inducible factor (HIF)-1α, whereas decreased HIF-2α, the transcriptional regulator of Nox and SOD-2, respectively. These IH-induced changes in the AM were absent in CBA rats. Moreover, IH increased splanchnic nerve activity and facilitated hypoxia-evoked catecholamine efflux from the AM and CBA prevented these effects. These findings suggest that IH-induced oxidative stress and catecholamine efflux in the AM occurs via carotid body chemoreflex involving HIF α isoform mediated imbalance in pro-, and anti-oxidant enzymes. PMID:26303481

  14. JAK2/STAT3 pathway mediating inflammatory responses in heatstroke-induced rats.

    PubMed

    Tao, Zhen; Cheng, Ming; Wang, Shu-Cai; Lv, Wei; Hu, Huai-Qiang; Li, Chuan-Fen; Cao, Bing-Zhen

    2015-01-01

    Heatstroke not only directly induces cell injury, but also causes large amounts of inflammatory mediators release and cells with extensive biological activities to induce a systemic inflammatory response and immune dysfunction. This study aimed to observe the effects of JAK2 inhibitor AG490 on the brain injury and inflammatory responses of rats with systemic heatstroke. Under the light microscope, the hippocampus tissues of rat with heatstroke were edema and apoptotic rate was increased. Up-regulation of malondialdehyde (MDA), nitric oxide synthase (iNOS), reactive oxygen species (ROS) and down-regulation of superoxide dismutase (SOD) were also found after heatstroke in rats, which compared with that of the control group. Heatstroke induced inflammation factors secretions and up-regulated levels of matrix metallopeptidase 2 and 9 (MMP2 and MMP-9) and systemic inflammatory response molecules including intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-beta 1 (TNF-β1) and cyclooxygenase-2 (COX-2). However, the JAK2 inhibitor AG490 was significantly attenuated the brain injury and inflammatory responses induced by heatstroke in rats. The survival time of heatstroke rats showed that AG490 notably lived longer than heatstroke rats without AG490 treatment. These findings suggest that AG490 may prevent the occurrence of heatstroke via inhibiting the JAK2/STAT3 pathway and the systemic inflammatory responses. PMID:26261556

  15. NMDA-induced neuronal survival is mediated through nuclear factor I-A in mice

    PubMed Central

    Zheng, Sika; Eacker, Stephen M.; Hong, Suk Jin; Gronostajski, Richard M.; Dawson, Ted M.; Dawson, Valina L.

    2010-01-01

    Identification of the signaling pathways that mediate neuronal survival signaling could lead to new therapeutic targets for neurologic disorders and stroke. Sublethal doses of NMDA can induce robust endogenous protective mechanisms in neurons. Through differential analysis of primary library expression and microarray analyses, here we have shown that nuclear factor I, subtype A (NFI-A), a member of the NFI/CAAT-box transcription factor family, is induced in mouse neurons by NMDA receptor activation in a NOS- and ERK-dependent manner. Knockdown of NFI-A induction using siRNA substantially reduced the neuroprotective effects of sublethal doses of NMDA. Further analysis indicated that NFI-A transcriptional activity was required for the neuroprotective effects of NMDA receptor activation. Additional evidence of the neuroprotective effects of NFI-A was provided by the observations that Nfia–/– neurons were highly sensitive to NMDA-induced excitotoxicity and were more susceptible to developmental cell death than wild-type neurons and that Nfia+/– mice were more sensitive to NMDA-induced intrastriatal lesions than were wild-type animals. These results identify NFI-A as what we believe to be a novel neuroprotective transcription factor with implications in neuroprotection and neuronal plasticity following NMDA receptor activation. PMID:20516644

  16. SARM1, Not MyD88, Mediates TLR7/TLR9-Induced Apoptosis in Neurons.

    PubMed

    Mukherjee, Piyali; Winkler, Clayton W; Taylor, Katherine G; Woods, Tyson A; Nair, Vinod; Khan, Burhan A; Peterson, Karin E

    2015-11-15

    Neuronal apoptosis is a key aspect of many different neurologic diseases, but the mechanisms remain unresolved. Recent studies have suggested a mechanism of innate immune-induced neuronal apoptosis through the stimulation of endosomal TLRs in neurons. TLRs are stimulated both by pathogen-associated molecular patterns as well as by damage-associated molecular patterns, including microRNAs released by damaged neurons. In the present study, we identified the mechanism responsible for TLR7/TLR9-mediated neuronal apoptosis. TLR-induced apoptosis required endosomal localization of TLRs but was independent of MyD88 signaling. Instead, apoptosis required the TLR adaptor molecule SARM1, which localized to the mitochondria following TLR activation and was associated with mitochondrial accumulation in neurites. Deficiency in SARM1 inhibited both mitochondrial accumulation in neurites and TLR-induced apoptosis. These studies identify a non-MyD88 pathway of TLR7/ TLR9 signaling in neurons and provide a mechanism for how innate immune responses in the CNS directly induce neuronal damage. PMID:26423149

  17. Deciphering the molecular and biologic processes that mediate histone deacetylase inhibitor-induced thrombocytopenia.

    PubMed

    Bishton, Mark J; Harrison, Simon J; Martin, Benjamin P; McLaughlin, Nicole; James, Chloé; Josefsson, Emma C; Henley, Katya J; Kile, Benjamin T; Prince, H Miles; Johnstone, Ricky W

    2011-03-31

    Histone deacetylase inhibitor (HDACI)-induced thrombocytopenia (TCP) is a major dose-limiting toxicity of this new class of drugs. Using preclinical models to study the molecular and biologic events that underpin this effect of HDACI, we found that C57BL/6 mice treated with both the HDAC1/2-selective HDACI romidepsin and the pan-HDACI panobinostat developed significant TCP. HDACI-induced TCP was not due to myelosuppression or reduced platelet lifespan, but to decreased platelet release from megakaryocytes. Cultured primary murine megakaryocytes showed reductions in proplatelet extensions after HDACI exposure and a dose-dependent increase in the phosphorylation of myosin light chain 2 (MLC2). Phosphorylation of MLC to phospho-MLC (pMLC) and subsequent proplatelet formation in megakaryocytes is regulated by the Rho-GTPase proteins Rac1, CDC42, and RhoA. Primary mouse megakaryocytes and the human megakaryoblastic cell line Meg-01 showed reductions in Rac1, CDC42, and RhoA protein levels after treatment with HDACIs. We were able to overcome HDACI-induced TCP by administering the mouse-specific thrombopoietin (TPO) mimetic AMP-4, which improved platelet numbers to levels similar to untreated controls. Our report provides the first detailed account of the molecular and biologic processes involved in HDACI-mediated TCP. Moreover, our preclinical studies provide evidence that dose-limiting TCP induced by HDACIs may be circumvented using a TPO mimetic. PMID:21292776

  18. JAK2/STAT3 pathway mediating inflammatory responses in heatstroke-induced rats

    PubMed Central

    Tao, Zhen; Cheng, Ming; Wang, Shu-Cai; Lv, Wei; Hu, Huai-Qiang; Li, Chuan-Fen; Cao, Bing-Zhen

    2015-01-01

    Heatstroke not only directly induces cell injury, but also causes large amounts of inflammatory mediators release and cells with extensive biological activities to induce a systemic inflammatory response and immune dysfunction. This study aimed to observe the effects of JAK2 inhibitor AG490 on the brain injury and inflammatory responses of rats with systemic heatstroke. Under the light microscope, the hippocampus tissues of rat with heatstroke were edema and apoptotic rate was increased. Up-regulation of malondialdehyde (MDA), nitric oxide synthase (iNOS), reactive oxygen species (ROS) and down-regulation of superoxide dismutase (SOD) were also found after heatstroke in rats, which compared with that of the control group. Heatstroke induced inflammation factors secretions and up-regulated levels of matrix metallopeptidase 2 and 9 (MMP2 and MMP-9) and systemic inflammatory response molecules including intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-beta 1 (TNF-β1) and cyclooxygenase-2 (COX-2). However, the JAK2 inhibitor AG490 was significantly attenuated the brain injury and inflammatory responses induced by heatstroke in rats. The survival time of heatstroke rats showed that AG490 notably lived longer than heatstroke rats without AG490 treatment. These findings suggest that AG490 may prevent the occurrence of heatstroke via inhibiting the JAK2/STAT3 pathway and the systemic inflammatory responses. PMID:26261556

  19. Reactive oxygen species mediate angiotensin II-induced leukocyte-endothelial cell interactions in vivo.

    PubMed

    Alvarez, A; Sanz, M J

    2001-08-01

    Chronically elevated angiotensin II (Ang-II)-induced hypertension is partly mediated by superoxide production. In this study, we have investigated whether the leukocyte-endothelial cell interactions elicited by Ang-II involve reactive oxygen species (ROS) generation. Intravital microscopy within the rat mesenteric microvessels was used. Superfusion (60 min) with Ang-II (1 nM) induced significant increases in leukocyte rolling flux, adhesion, and emigration, which were inhibited by pretreatment with superoxide dismutase or catalase. Dihydrorhodamine-123 oxidation indicated that ROS are primarily produced by the vessel wall. Administration of dimethylthiourea, desferrioxamine, or N-acetylcysteine provoked significant reductions in Ang-II-induced leukocyte-endothelial cell interactions. In addition, a blockade of platelet-activating factor or leukotrienes also attenuated such responses significantly. The results presented indicate that in vivo Ang-II-induced leukocyte recruitment is dependent on the generation of intra- and extracellular ROS. Therefore, the use of anti-oxidants might constitute an alternative therapy for the control of the subendothelial leukocyte infiltration associated with hypertension and atherosclerosis. PMID:11493611

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

    SciTech Connect

    Nguyen Ngoc, Tam Dan; Son, Young-Ok; Lim, Shin-Saeng; Shi, Xianglin; Kim, Jong-Ghee; Heo, Jung Sun; Choe, Youngji; Jeon, Young-Mi; Lee, Jeong-Chae

    2012-03-15

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

  1. Indirect decentralized learning control

    NASA Technical Reports Server (NTRS)

    Longman, Richard W.; Lee, Soo C.; Phan, M.

    1992-01-01

    The new field of learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented a theory of indirect learning control based on use of indirect adaptive control concepts employing simultaneous identification and control. This paper develops improved indirect learning control algorithms, and studies the use of such controllers in decentralized systems. The original motivation of the learning control field was learning in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. The basic result of the paper is to show that stability of the indirect learning controllers for all subsystems when the coupling between subsystems is turned off, assures convergence to zero tracking error of the decentralized indirect learning control of the coupled system, provided that the sample time in the digital learning controller is sufficiently short.

  2. Atorvastatin-induced cardioprotection is mediated by increasing inducible nitric oxide synthase and consequent S-nitrosylation of cyclooxygenase-2.

    PubMed

    Atar, Shaul; Ye, Yumei; Lin, Yu; Freeberg, Sheldon Y; Nishi, Shawn P; Rosanio, Salvatore; Huang, Ming-He; Uretsky, Barry F; Perez-Polo, Jose R; Birnbaum, Yochai

    2006-05-01

    We determined the effects of cyclooxygenase-1 (COX-1; SC-560), COX-2 (SC-58125), and inducible nitric oxide synthase (iNOS; 1400W) inhibitors on atorvastatin (ATV)-induced myocardial protection and whether iNOS mediates the ATV-induced increases in COX-2. Sprague-Dawley rats received 10 mg ATV.kg(-1).day(-1) added to drinking water or water alone for 3 days and received intravenous SC-58125, SC-560, 1400W, or vehicle alone. Anesthesia was induced with ketamine and xylazine and maintained with isoflurane. Fifteen minutes after intravenous injection rats underwent 30-min myocardial ischemia followed by 4-h reperfusion [infarct size (IS) protocol], or the hearts were explanted for biochemical analysis and immunoblotting. Left ventricular weight and area at risk (AR) were comparable among groups. ATV reduced IS to 12.7% (SD 3.1) of AR, a reduction of 64% vs. 35.1% (SD 7.6) in the sham-treated group (P < 0.001). SC-58125 and 1400W attenuated the protective effect without affecting IS in the non-ATV-treated rats. ATV increased calcium-independent NOS (iNOS) [11.9 (SD 0.8) vs. 3.9 (SD 0.1) x 1,000 counts/min; P < 0.001] and COX-2 [46.7 (SD 1.1) vs. 6.5 (SD 1.4) pg/ml of 6-keto-PGF(1alpha); P < 0.001] activity. Both SC-58125 and 1400W attenuated this increase. SC-58125 did not affect iNOS activity, whereas 1400W blocked iNOS activity. COX-2 was S-nitrosylated in ATV-treated but not sham-treated rats or rats pretreated with 1400W. COX-2 immunoprecipitated with iNOS but not with endothelial nitric oxide synthase. We conclude that ATV reduced IS by increasing the activity of iNOS and COX-2, iNOS is upstream to COX-2, and iNOS activates COX-2 by S-nitrosylation. These results are consistent with the hypothesis that preconditioning effects are mediated via PG. PMID:16339820

  3. Bushen Zhuangjin decoction inhibits TM-induced chondrocyte apoptosis mediated by endoplasmic reticulum stress

    PubMed Central

    LIN, PINGDONG; WENG, XIAPING; LIU, FAYUAN; MA, YUHUAN; CHEN, HOUHUANG; SHAO, XIANG; ZHENG, WENWEI; LIU, XIANXIANG; YE, HONGZHI; LI, XIHAI

    2015-01-01

    Chondrocyte apoptosis triggered by endoplasmic reticulum (ER) stress plays a vital role in the pathogenesis of osteoarthritis (OA). Bushen Zhuangjin decoction (BZD) has been widely used in the treatment of OA. However, the cellular and molecular mechanisms responsible for the inhibitory effects of BZD on chondrocyte apoptosis remain to be elucidated. In the present study, we investigated the effects of BZD on ER stress-induced chondrocyte apoptosis using a chondrocyte in vitro model of OA. Chondrocytes obtained from the articular cartilage of the knee joints of Sprague Dawley (SD) rats were detected by immunohistochemical staining for type II collagen. The ER stress-mediated apoptosis of tunicamycin (TM)-stimulated chondrocytes was detected using 4-phenylbutyric acid (4-PBA). We found that 4-PBA inhibited TM-induced chondrocyte apoptosis, which confirmed the successful induction of chondrocyte apoptosis. BZD enhanced the viability of the TM-stimulated chondrocytes in a dose- and time-dependent manner, as shown by MTT assay. The apoptotic rate and the loss of mitochondrial membrane potential (ΔΨm) of the TM-stimulated chondrocytes treated with BZD was markedly decreased compared with those of chondrocytes not treated with BZD, as shown by 4′,6-diamidino-2-phenylindole (DAPI) staining, Annexin V-FITC binding assay and JC-1 assay. To further elucidate the mechanisms responsible for the inhibitory effects of BZD on TM-induced chondrocyte apoptosis mediated by ER stress, the mRNA and protein expression levels of binding immunoglobulin protein (Bip), X-box binding protein 1 (Xbp1), activating transcription factor 4 (Atf4), C/EBP-homologous protein (Chop), caspase-9, caspase-3, B-cell lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax) were measured by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. In the TM-stimulated chondrocytes treated with BZD, the mRNA and protein expression levels of Bip, Atf4, Chop, caspase-9, caspase-3

  4. ROLES OF OPIOID RECEPTOR SUBTYPES IN MEDIATING ALCOHOL SEEKING INDUCED BY DISCRETE CUES AND CONTEXT

    PubMed Central

    Marinelli, Peter W.; Funk, Douglas; Harding, Stephen; Li, Zhaoxia; Juzytsch, Walter; Lê, A.D.

    2009-01-01

    The aim of this study was to assess the effects of selective blockade of the delta (DOP) or mu opioid (MOP) receptors on alcohol seeking induced by discrete cues and context. In Experiment 1, rats were trained to self-administer alcohol in an environment with distinct sensory properties. After extinction in a different context with separate sensory properties, rats were tested for context-induced renewal in the original context following treatment with the DOP receptor antagonist naltrindole (0 – 15-mg/kg, IP) or the MOP receptor antagonist CTOP (0 – 3-µg/kg ICV). In a separate set of experiments, reinstatement was tested with the presentation of a discrete light+tone cue previously associated with alcohol delivery, following extinction without the cue. In Experiment 2, the effects of naltrindole (0 – 5-mg/kg, IP) or CTOP (0 – 3-µg/kg µg ICV) were assessed. For context-induced renewal, 7.5-mg/kg naltrindole reduced responding without affecting locomotor activity. Both doses of CTOP attenuated responding in the first 15 min of the renewal test session; however, total responses did not differ at the end of the session. For discrete cue-induced reinstatement, 1 and 5-mg/kg naltrindole attenuated responding, but CTOP had no effect. We conclude that while DOP receptors mediate alcohol seeking induced by discrete cues and context, MOP receptors may play a modest role only in context-induced renewal. These findings point to a differential involvement of opioid receptor subtypes in the effects of different kinds of conditioned stimuli on alcohol seeking, and support a more prominent role for DOP receptors. PMID:19686472

  5. Roles of opioid receptor subtypes in mediating alcohol-seeking induced by discrete cues and context.

    PubMed

    Marinelli, Peter W; Funk, Douglas; Harding, Stephen; Li, Zhaoxia; Juzytsch, Walter; Lê, A D

    2009-08-01

    The aim of this study was to assess the effects of selective blockade of the delta (DOP) or mu (MOP) opioid receptors on alcohol-seeking induced by discrete cues and context. In Experiment 1, rats were trained to self-administer alcohol in an environment with distinct sensory properties. After extinction in a different context with separate sensory properties, rats were tested for context-induced renewal in the original context following treatment with the DOP receptor antagonist naltrindole (0-15 mg/kg, i.p.) or the MOP receptor antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH(2) (CTOP) (0-3 microg/4 microL, i.c.v.). In Experiment 2, reinstatement was tested with the presentation of a discrete light + tone cue previously associated with alcohol delivery, following extinction without the cue. The effects of naltrindole (0-5 mg/kg, i.p.) or CTOP (0-3 microg/4 microL, i.c.v.) were assessed. For context-induced renewal, 7.5 mg/kg naltrindole reduced responding without affecting locomotor activity. Both doses of CTOP attenuated responding in the first 15 min of the renewal test session; however, total responses did not differ at the end of the session. For discrete-cue-induced reinstatement, 1 and 5 mg/kg naltrindole attenuated responding but CTOP had no effect. We conclude that whereas DOP receptors mediate alcohol-seeking induced by discrete cues and context, MOP receptors may play a modest role only in context-induced renewal. These findings point to a differential involvement of opioid receptor subtypes in the effects of different kinds of conditioned stimuli on alcohol-seeking and support a more prominent role for DOP receptors. PMID:19686472

  6. Intrarenal renin-angiotensin system mediates fatty acid-induced ER stress in the kidney.

    PubMed

    Li, Chunling; Lin, Yu; Luo, Renfei; Chen, Shaoming; Wang, Feifei; Zheng, Peili; Levi, Moshe; Yang, Tianxin; Wang, Weidong

    2016-03-01

    Obesity-related kidney disease is related to caloric excess promoting deleterious cellular responses. Accumulation of saturated free fatty acids in tubular cells produces lipotoxicity involving significant cellular dysfunction and injury. The objectives of this study were to elucidate the role of renin-angiotensin system (RAS) activation in saturated fatty acid-induced endoplasmic reticulum (ER) stress in cultured human proximal tubule epithelial cells (HK2) and in mice fed with a high-fat diet. Treatment with saturated fatty acid palmitic acid (PA; 0.8 mM) for 24 h induced ER stress in HK2, leading to an unfolded protein response as reflected by increased expressions of the ER chaperone binding immunoglobulin protein (BiP) and proapoptotic transcription factor C/EBP homologous protein (CHOP) protein as evaluated by immunoblotting. PA treatment also induced increased protein expression of inositol requiring protein 1α (IRE1α), phosphorylated eukaryotic initiation factor-α (eIF2α), and activating transcription factor 4 (ATF4) as well as activation of caspase-3. PA treatment was associated with increased angiotensin II levels in cultured medium. The angiotensin II type 1 receptor (AT1R) blocker valsartan or renin inhibitor aliskiren dramatically suppressed PA-induced upregulation of BiP, CHOP, IRE1α, p-eIF2α, and ATF4 in HK2 cells. In contrast, valsartan or aliskiren did not prevent ER stress induced by tunicamycin. C57BL/6 mice fed with a high-fat diet for 14 wk exhibited increased protein expressions of BiP and CHOP compared with control mice, which were significantly attenuated by the valsartan treatment. Increased angiotensin II levels in serum and urine were observed in mice fed with a high-fat diet when compared with controls. It is suggested that the intrarenal RAS activation may play an important role in diabetic kidney injury via mediating ER stress induced by saturated fatty acid. PMID:26672616

  7. PKA-mediated responses in females' estrous cycle affect cocaine-induced responses in dopamine-mediated intracellular cascades.

    PubMed

    Weiner, J; Sun, W Lun; Zhou, L; Kreiter, C M; Jenab, S; Quiñones-Jenab, V

    2009-07-01

    An extensive body of literature provides evidence for both sexual dimorphism and menstrual cycle effects in drug abuse patterns and behavioral responses. However, the cellular mechanisms underlying sexually dimorphic responses to and hormonal effects on cocaine use remain unclear. We hypothesized that endogenous hormonal fluctuations during the estrous cycle of rats modulate cocaine's effects on dopamine- and PKA-mediated intracellular responses. To test this hypothesis, intact female rats at different stages of their cycle received a single injection of saline or cocaine (20 mg/kg) and were sacrificed after 15 or 60 min. The nucleus accumbens (NAc) and caudate putamen (CPu) were dissected and analyzed via Western blot for total and phosphorylated (p-thr34) dopamine- and 3'-5'-cyclic AMP-regulated phosphoprotein with molecular weight 32 kDa (DARPP-32), PP1, PP2B (CNA1 and CNB1 subunits), PKA, CREB, cFOS, and Delta-FosB. Our results show that saline-treated rats had estrous cycle-related differences in protein levels of pCREB, DARPP-32, p-thr34-DARPP-32, PP1, and CNA1. Saline-treated female rats in the estrus stage had higher levels of pCREB in the NAc, but cocaine-treatment lowered pCREB levels. The estrous cycle also significantly affected the magnitude of change for p-thr34-DARPP-32 protein levels in both the NAc and CPu. Sixty minutes of cocaine administration increased p-thr34-DARPP-32 levels in the NAc of rats during estrus and proestrus and in the CPu of rats in diestrus. Furthermore, cocaine-induced changes in PP1 protein levels in the NAc were also affected by the stage of the cycle; 60 min of cocaine administration increased PP1 levels in the NAc of rats during diestrus, whereas PP-1 levels decreased in rats during estrus. Taken together, these novel findings suggest that hormonal fluctuations during the estrous cycle may contribute to the previously reported sex differences in the PKA pathway and in behavioral responses to cocaine. PMID:19348873

  8. Probability of pipe fracture in the primary coolant loop of a PWR plant. Volume 8. Pipe fracture indirectly induced by an earthquake. Load Combination Program, Project I final report

    SciTech Connect

    Streit, R.D.

    1981-06-01

    This volume considers the probability that a double-ended guillotine break in the primary coolant loop of a pressurized water reactor occurs simultaneously with (and is indirectly caused by) a seismic event. The pipe break is a consequence of a seismically initiated failure in a system other than the primary piping itself. Events studied that can lead to an indirectly induced pipe break include structural and mechanical failures, missile impact, pressure transients, jet impingement, fire, and explosion. Structural failures of the supports for the reactor pressure vessel, reactor coolant pump, and steam generator have the highest probability of causing a double-ended pipe break. Furthermore, we found that structural failure of the containment dome and failure of the reactor coolant pump flywheel have the highest potential for a missile-caused pipe break. Since structural failure proved to be a major factor, we developed a model to estimate the probability of structural failure; this model is based on the engineering factors of safety and seismic hazard. preliminary results indicate that the probability of a double-ended pipe break indirectly caused by a seismic event during the plant life is on the order of 10/sup -9/.

  9. Smad, but not MAPK, pathway mediates the expression of type I collagen in radiation induced fibrosis

    SciTech Connect

    Yano, Hiroyuki; Hamanaka, Ryoji; Nakamura, Miki; Sumiyoshi, Hideaki; Matsuo, Noritaka; Yoshioka, Hidekatsu

    2012-02-17

    Highlights: Black-Right-Pointing-Pointer We examine how radiation affects the expression level and signal pathway of collagen. Black-Right-Pointing-Pointer TGF-{beta}1 mRNA is elevated earlier than those of collagen genes after irradiation. Black-Right-Pointing-Pointer Smad pathway mediates the expression of collagen in radiation induced fibrosis. Black-Right-Pointing-Pointer MAPK pathways are not affected in the expression of collagen after irradiation. -- Abstract: Radiation induced fibrosis occurs following a therapeutic or accidental radiation exposure in normal tissues. Tissue fibrosis is the excessive accumulation of collagen and other extracellular matrix components. This study investigated how ionizing radiation affects the expression level and signal pathway of type I collagen. Real time RT-RCR showed that both {alpha}1and {alpha}2 chain of type I collagen mRNA were elevated from 48 h after irradiation with 10 Gy in NIH3T3 cells. The relative luciferase activities of both genes and type I collagen marker were elevated at 72 h. TGF-{beta}1 mRNA was elevated earlier than those of type I collagen genes. A Western blot analysis showed the elevation of Smad phosphorylation at 72 h. Conversely, treatment with TGF-{beta} receptor inhibitor inhibited the mRNA and relative luciferase activity of type I collagen. The phosphorylation of Smad was repressed with the inhibitor, and the luciferase activity was cancelled using a mutant construct of Smad binding site of {alpha}2(I) collagen gene. However, the MAPK pathways, p38, ERK1/2 and JNK, were not affected with specific inhibitors or siRNA. The data showed that the Smad pathway mediated the expression of type I collagen in radiation induced fibrosis.

  10. Oncogenic mutations in intestinal adenomas regulate Bim-mediated apoptosis induced by TGF-β

    PubMed Central

    Wiener, Zoltán; Band, Arja M.; Kallio, Pauliina; Högström, Jenny; Hyvönen, Ville; Kaijalainen, Seppo; Ritvos, Olli; Haglund, Caj; Kruuna, Olli; Robine, Sylvie; Louvard, Daniel; Ben-Neriah, Yinon; Alitalo, Kari

    2014-01-01

    In the majority of microsatellite-stable colorectal cancers (CRCs), an initiating mutation occurs in the adenomatous polyposis coli (APC) or β-catenin gene, activating the β-catenin/TCF pathway. The progression of resulting adenomas is associated with oncogenic activation of KRas and inactivation of the p53 and TGF-β/Smad functions. Most established CRC cell lines contain mutations in the TGF-β/Smad pathway, but little is known about the function of TGF-β in the early phases of intestinal tumorigenesis. We used mouse and human ex vivo 3D intestinal organoid cultures and in vivo mouse models to study the effect of TGF-β on the Lgr5+ intestinal stem cells and their progeny in intestinal adenomas. We found that the TGF-β–induced apoptosis in Apc-mutant organoids, including the Lgr5+ stem cells, was mediated by up-regulation of the BH3-only proapoptotic protein Bcl-2–like protein 11 (Bim). BH3-mimetic compounds recapitulated the effect of Bim not only in the adenomas but also in human CRC organoids that had lost responsiveness to TGF-β–induced apoptosis. However, wild-type intestinal crypts were markedly less sensitive to TGF-β than Apc-mutant adenomas, whereas the KRas oncogene increased resistance to TGF-β via the activation of the Erk1/2 kinase pathway, leading to Bim down-regulation. Our studies identify Bim as a critical mediator of TGF-β–induced apoptosis in intestinal adenomas and show that the common progression mutations modify Bim levels and sensitivity to TGF-β during intestinal adenoma development. PMID:24825889

  11. Hypoxia-induced hypothermia mediated by GABA in the rostral parapyramidal area of the medulla oblongata.

    PubMed

    Osaka, T

    2014-05-16

    Hypoxia evokes a regulated decrease in the body core temperature (Tc) in a variety of animals. The neuronal mechanisms of this response include, at least in part, glutamatergic activation in the lateral preoptic area (LPO) of the hypothalamus. As the sympathetic premotor neurons in the medulla oblongata constitute a cardinal relay station in the descending neuronal pathway from the hypothalamus for thermoregulation, their inhibition can also be critically involved in the mechanisms of the hypoxia-induced hypothermia. Here, I examined the hypothesis that hypoxia-induced hypothermia is mediated by glutamate-responsive neurons in the LPO that activate GABAergic transmission in the rostral raphe pallidus (rRPa) and neighboring parapyramidal region (PPy) of the medulla oblongata in urethane-chloralose-anesthetized, neuromuscularly blocked, artificially ventilated rats. Unilateral microinjection of GABA (15nmol) into the rRPa and PPy regions elicited a prompt increase in tail skin temperature (Ts) and decreases in Tc, oxygen consumption rate (VO2), and heart rate. Next, when the GABAA receptor blocker bicuculline methiodide (bicuculline methiodide (BMI), 10pmol) alone was microinjected into the rRPa, it elicited unexpected contradictory responses: simultaneous increases in Ts, VO2 and heart rate and a decrease in Tc. Then, when BMI was microinjected bilaterally into the PPy, no direct effect on Ts was seen; and thermogenic and tachycardic responses were slight. However, pretreatment of the PPy with BMI, but not vehicle saline, greatly attenuated the hypothermic responses evoked by hypoxic (10%O2-90%N2, 5min) ventilation or bilateral microinjections of glutamate (5nmol, each side) into the LPO. The results suggest that hypoxia-induced hypothermia was mediated, at least in part, by the activation of GABAA receptors in the PPy. PMID:24607346

  12. Glucocorticoids mediate stress-induced impairment of retrieval of stimulus-response memory.

    PubMed

    Atsak, Piray; Guenzel, Friederike M; Kantar-Gok, Deniz; Zalachoras, Ioannis; Yargicoglu, Piraye; Meijer, Onno C; Quirarte, Gina L; Wolf, Oliver T; Schwabe, Lars; Roozendaal, Benno

    2016-05-01

    Acute stress and elevated glucocorticoid hormone levels are well known to impair the retrieval of hippocampus-dependent 'declarative' memory. Recent findings suggest that stress might also impair the retrieval of non-hippocampal memories. In particular, stress shortly before retention testing was shown to impair the retrieval of striatal stimulus-response associations in humans. However, the mechanism underlying this stress-induced retrieval impairment of non-hippocampal stimulus-response memory remains elusive. In the present study, we investigated whether an acute elevation in glucocorticoid levels mediates the impairing effects of stress on retrieval of stimulus-response memory. Male Sprague-Dawley rats were trained on a stimulus-response task in an eight-arm radial maze until they learned to associate a stimulus, i.e., cue, with a food reward in one of the arms. Twenty-four hours after successful acquisition, they received a systemic injection of vehicle, corticosterone (1mg/kg), the corticosterone-synthesis inhibitor metyrapone (35mg/kg) or were left untreated 1h before retention testing. We found that the corticosterone injection impaired the retrieval of stimulus-response memory. We further found that the systemic injection procedure per se was stressful as the vehicle administration also increased plasma corticosterone levels and impaired the retrieval of stimulus-response memory. However, memory retrieval was not impaired when rats were tested 2min after the systemic vehicle injection, before any stress-induced elevation in corticosterone levels had occurred. Moreover, metyrapone treatment blocked the effect of injection stress on both plasma corticosterone levels and memory retrieval impairment, indicating that the endogenous corticosterone response mediates the stress-induced memory retrieval impairment. None of the treatments affected rats' locomotor activity or motivation to search for the food reward within the maze. These findings show that stress

  13. Microglial activation mediates host neuronal survival induced by neural stem cells.

    PubMed

    Wu, Hui-Mei; Zhang, Li-Feng; Ding, Pei-Shang; Liu, Ya-Jing; Wu, Xu; Zhou, Jiang-Ning

    2014-07-01

    The rational of neural stem cells (NSCs) in the therapy of neurological disease is either to replace dead neurons or to improve host neuronal survival, the latter of which has got less attention and the underlying mechanism is as yet little known. Using a transwell co-culture system, we reported that, in organotypic brain slice cultures, NSCs significantly improved host neuronal viability. Interestingly, this beneficial effect of NSCs was abrogated by a microglial inhibitor minocycline, while it was mimicked by a microglial agonist, Toll-like receptor 9 (TLR9) ligand CpG-ODN, which supports the pro-vital mediation by microglia on this NSCs-improved neuronal survival. Moreover, we showed that NSCs significantly induced host microglial movement and higher expression of a microglial marker IBA-1, the latter of which was positively correlated with TLR9 or extracellular-regulated protein kinases 1/2 (ERK1/2) activation. Real-time PCR revealed that NSCs inhibited the expression of pro-inflammatory molecules, but significantly increased the expression of molecules associated with a neuroprotective phenotype such as CX3CR1, triggering receptor expressed on myeloid cells-2 (TREM2) and insulin growth factor 1 (IGF-1). Similarly, in the microglia cells, NSCs induced the same microglial response as that in the slices. Further treatment with TLR9 ligand CpG-ODN, TLR9 inhibitor chloroquine (CQ) or ERK1/2 inhibitor U0126 demonstrated that TLR9-ERK1/2 pathway was involved in the NSCs-induced microglial activation. Collectively, this study indicated that NSCs improve host neuronal survival by switching microglia from a detrimental to a neuroprotective phenotype in adult mouse brain, and the microglial TLR9-ERK1/2 pathway seems to participate in this NSCs-mediated rescue action. PMID:24725889

  14. Eosinophil resistance to glucocorticoid-induced apoptosis is mediated by the transcription factor NFIL3.

    PubMed

    Pazdrak, Konrad; Moon, Young; Straub, Christof; Stafford, Susan; Kurosky, Alexander

    2016-04-01

    The mainstay of asthma therapy, glucocorticoids (GCs) exert their therapeutic effects through the inhibition of inflammatory signaling and induction of eosinophil apoptosis. However, laboratory and clinical observations of GC-resistant asthma suggest that GCs' effects on eosinophil viability may depend on the state of eosinophil activation. In the present study we demonstrate that eosinophils stimulated with IL-5 show impaired pro-apoptotic response to GCs. We sought to determine the contribution of GC-mediated transactivating (TA) and transrepressing (TR) pathways in modulation of activated eosinophils' response to GC by comparing their response to the selective GC receptor (GR) agonist Compound A (CpdA) devoid of TA activity to that upon treatment with Dexamethasone (Dex). IL-5-activated eosinophils showed contrasting responses to CpdA and Dex, as IL-5-treated eosinophils showed no increase in apoptosis compared to cells treated with Dex alone, while CpdA elicited an apoptotic response regardless of IL-5 stimulation. Proteomic analysis revealed that both Nuclear Factor IL-3 (NFIL3) and Map Kinase Phosphatase 1 (MKP1) were inducible by IL-5 and enhanced by Dex; however, CpdA had no effect on NFIL3 and MKP1 expression. We found that inhibiting NFIL3 with specific siRNA or by blocking the IL-5-inducible Pim-1 kinase abrogated the protective effect of IL-5 on Dex-induced apoptosis, indicating crosstalk between IL-5 anti-apoptotic pathways and GR-mediated TA signaling occurring via the NFIL3 molecule. Collectively, these results indicate that (1) GCs' TA pathway may support eosinophil viability in IL-5-stimulated cells through synergistic upregulation of NFIL3; and (2) functional inhibition of IL-5 signaling (anti-Pim1) or the use of selective GR agonists that don't upregulate NFIL3 may be effective strategies for the restoring pro-apoptotic effect of GCs on IL-5-activated eosinophils. PMID:26880402

  15. Nitric oxide-induced changes in intracellular zinc homeostasis are mediated by metallothionein/thionein.

    PubMed

    St Croix, Claudette M; Wasserloos, K J; Dineley, K E; Reynolds, I J; Levitan, E S; Pitt, B R

    2002-02-01

    We hypothesized that metallothionein (MT), a cysteine-rich protein with a strong affinity for Zn(2+), plays a role in nitric oxide (NO) signaling events via sequestration or release of Zn(2+) by the unique thiolate clusters of the protein. Exposing mouse lung fibroblasts (MLF) to the NO donor S-nitrosocysteine resulted in 20-30% increases in fluorescence of the Zn(2+)-specific fluorophore Zinquin that were rapidly reversed by the Zn(2+) chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine. The absence of a NO-mediated increase in labile Zn(2+) in MLF from MT knockouts and its restoration after MT complementation by adenoviral gene transfer inferred a critical role for MT in the regulation of Zn(2+) homeostasis by NO. Additional data obtained in sheep pulmonary artery endothelial cells suggested a role for the apo form of MT, thionein (T), as a Zn(2+)-binding protein in intact cells, as overexpression of MT caused inhibition of NO-induced changes in labile Zn(2+) that were reversed by Zn(2+) supplementation. Furthermore, fluorescence-resonance energy-transfer data showed that overexpression of green fluorescent protein-modified MT prevented NO-induced conformational changes, which are indicative of Zn(2+) release from thiolate clusters. This effect was restored by Zn(2+) supplementation. Collectively, these data show that MT mediates NO-induced changes in intracellular Zn(2+) and suggest that the ratio of MT to T can regulate Zn(2+) homeostasis in response to nitrosative stress. PMID:11792622

  16. Indirect Ultraviolet-Reactivation of Phage λ

    PubMed Central

    George, Jacqueline; Devoret, Raymond; Radman, Miroslav

    1974-01-01

    When an F- recipient Escherichia coli K12 bacterium receives Hfr or F-lac+ DNA from an ultraviolet-irradiated donor, its capacity to promote DNA repair and mutagenesis of ultraviolet-damaged phage λ is substantially increased. We call this phenomenon indirect ultraviolet-reactivation, since its features are essentially the same as those of ultraviolet-reactivation; this repair process occurs in pyrimidine dimer excision-deficient strains and produces clear plaque mutations of the restored phage. Moreover, this process is similar to indirect ultraviolet-induction of prophage λ, since it is promoted by conjugation. However, contrarily to indirect induction, it is produced by Hfr donors and occurs in recipients restricting the incoming ultraviolet-damaged donor DNA. The occurrence of indirect ultraviolet-reactivation provides evidence for the existence in E. coli of an inducible error-prone mechanism for the repair of DNA. PMID:4589889

  17. TLR4-mediated NF-κB signaling pathway mediates HMGB1-induced pancreatic injury in mice with severe acute pancreatitis

    PubMed Central

    LI, GANG; WU, XUEJUN; YANG, LE; HE, YUXIANG; LIU, YANG; JIN, XING; YUAN, HAI

    2016-01-01

    Severe acute pancreatitis (SAP) is an extremely dangerous acute abdominal disorder which causes multiple complications and has a high mortality rate. Previous research has suggested that high-mobility group box 1 (HMGB1) plays an important role in the pathogenesis of SAP; however, the mechanisms underlying this strong correlation remain unclear. In this study, to further investigate whether HMGB1 acts as a stimulating factor, and whether Toll-like receptor 4 (TLR4) acts as its major mediator in the development of pancreatic injury during SAP, recombinant human HMGB1 (rhHMGB1) and TLR4-deficient mice were used. We found that HMGB1 and TLR4 were highly expressed, and nuclear factor-κB (NF-κB) was activated in our mouse model of SAP. We noted that the rhHMGB1 pancreas-targeted injection activated the TLR4-mediated NF-κB signaling pathway and induced pancreatic injury in wild-type mice. In TLR4-deficient mice, the rhHMGB1-induced activation of NF-κB and pathological changes in the pancreas were less evident than in wild-type mice. Therefore, this study provides evidence that HMGB1 promotes the pathogenesis of pancreatitis, and its downstream TLR4-mediated NF-κB signaling pathway is a potential important mediator in the development of this form of pancreatic injury. PMID:26719855

  18. Inhibition effect of cypermethrin mediated by co-regulators SRC-1 and SMRT in interleukin-6-induced androgen receptor activation.

    PubMed

    Wang, Qi; Zhou, Ji-Long; Wang, Hui; Ju, Qiang; Ding, Zhen; Zhou, Xiao-Long; Ge, Xing; Shi, Qiao-Mei; Pan, Chen; Zhang, Jin-Peng; Zhang, Mei-Rong; Yu, Hong-Min; Xu, Li-Chun

    2016-09-01

    It is hypothesized that the pesticide cypermethrin may induce androgen receptor (AR) antagonism via ligand-independent mechanisms. The Real-Time Cell Analysis (RTCA) iCELLigence system was used to investigate the inhibitory effect of cypermethrin on interleukin-6 (IL-6)-induced ligand-independent LNCaP cell growth. Then, the mammalian two-hybrid assays were applied to clarify whether the mechanism of IL-6-induced AR antagonism of cypermethrin was associated with the interactions of the AR and co-activator steroid receptor co-activator-1 (SRC-1) and co-repressor silencing mediator for retinoid and thyroid hormone receptors (SMRT). Cypermethrin inhibited the LNCaP cell growth induced by IL-6. The interactions of AR-SRC-1 and AR-SMRT mediated by IL-6 were suppressed by cypermethrin. The results indicate that the IL-6-mediated AR antagonism induced by cypermethrin is related to repress the recruitment of co-regulators SRC-1 and SMRT to the AR in a ligand-independent manner. Inhibition of the interactions of AR-SRC-1 and AR-SMRT mediated by IL-6 contributes to the AR antagonism induced by cypermethrin. PMID:27239967

  19. Lipopolysaccharide-induced cytokine expression in alveolar epithelial cells: role of PKCζ-mediated p47phox phosphorylation.

    PubMed

    Leverence, Jeremy T; Medhora, Meetha; Konduri, Girija G; Sampath, Venkatesh

    2011-01-15

    Chronic inflammation incited by bacteria in the saccular lung of premature infants contributes to the pathogenesis of bronchopulmonary dysplasia (BPD). LPS-mediated type II alveolar epithelial cell (AEC) injury induces the expression of pro-inflammatory cytokines that trigger pulmonary neutrophil influx, alveolar matrix degradation and lung remodeling. We hypothesized that NADPH oxidase (Nox)-dependent mechanisms mediate LPS-induced cytokine expression in AEC. We examined the role of p47phox in mediating LPS-dependent inflammatory cytokine expression in A549 cells (which exhibit phenotypic features characteristic of type II AEC) and elucidated the proximal signaling events by which Nox is activated by LPS. LPS-induced ICAM-1 and IL-8 expression was associated with increased superoxide formation in AEC. LPS-mediated oxidative stress and cytokine expression was inhibited by apocynin and augmented by PMA demonstrating that Nox-dependent redox signaling regulates LPS-dependent pro-inflammatory signaling in AEC. In LPS-treated cells, p47phox translocated from the cytoplasm to the perinuclear region and co-localized with gp91phox. LPS also induced a temporal increase in p47phox serine304 phosphorylation in AEC. While inhibition of classical PKC and novel PKC with calphostin and rottlerin did not inhibit ICAM-1 or IL-8 expression, the myristolyated PKCζ pseudosubstrate peptide (a specific inhibitor of PKCζ) inhibited LPS-induced cytokine expression in AEC. Inhibition of PKCζ also attenuated LPS-mediated p47phox phosphorylation and perinuclear translocation in AEC. Consistent with these data, LPS activated PKCζ in AEC as evidenced by increased threonine410 phophorylation. We conclude that PKCζ-mediated p47phox activation regulates LPS-dependent cytokine expression in AEC. Selective inhibition of PKCζ or p47phox might attenuate LPS-mediated inflammation and alveolar remodeling in BPD. PMID:20920494

  20. Artesunate induces apoptosis via a ROS-independent and Bax-mediated intrinsic pathway in HepG2 cells.

    PubMed

    Qin, Guiqi; Wu, Liping; Liu, Hongyu; Pang, Yilin; Zhao, Chubiao; Wu, Shengnan; Wang, Xiaoping; Chen, Tongsheng

    2015-08-15

    This study aims to explore the detail molecular mechanism by which artesunate (ARS), an artemisinin derivative, induces apoptosis in HepG2 cells. ARS induced a loss of mitochondrial transmemberane potential (ΔΨm), phosphatidylserine (PS) externalization, as well as activations of Bax/Bak and caspases indicative of apoptosis induction. Silencing Bax but not Bak significantly inhibited ARS-induced apoptosis, demonstrating the key role of the Bax-mediated intrinsic pathway. Although ARS increased intracellular reactive oxygen species (ROS), ARS-induced apoptosis was neither prevented by pretreatment with ROS scavengers nor potentiated by pretreatment with l-buthionine-sulfoximine (BSO) that enhanced the ARS-induced intracellular ROS generation, demonstrating that ROS was not involved in ARS-induced apoptosis. In addition, ARS did not induce Bid translocation to mitochondria, and the cytotoxicity of ARS was not prevented by silencing Bim, Puma or Mcl-1, but was significantly enhanced by HA14-1 pretreatment, demonstrating that Bcl-2/-xl instead of Bid and Bim as well as Puma may be the upstream factor to regulate the Bax-mediated intrinsic pathway. Collectively, our data demonstrate that ARS induces ROS-independent apoptosis via the Bax-mediated intrinsic pathway in HepG2 cells. PMID:26163896

  1. Nicotine exposure induces bronchial epithelial cell apoptosis and senescence via ROS mediated autophagy-impairment.

    PubMed

    Bodas, Manish; Van Westphal, Colin; Carpenter-Thompson, Rhett; K Mohanty, Dillip; Vij, Neeraj

    2016-08-01

    Waterpipe smoking and e-cigarette vaping, the non-combustible sources of inhaled nicotine exposure are increasingly becoming popular and marketed as safer alternative to cigarette smoking. Hence, this study was designed to investigate the impact of inhaled nicotine exposure on disease causing COPD-emphysema mechanisms. For in vitro studies, human bronchial epithelial cells (Beas2b) were treated with waterpipe smoke extract (WPSE, 5%), nicotine (5mM), and/or cysteamine (250μM, an autophagy inducer and anti-oxidant drug), for 6hrs. We observed significantly (p<0.05) increased ubiquitinated protein-accumulation in the insoluble protein fractions of Beas2b cells treated with WPSE or nicotine that could be rescued by cysteamine treatment, suggesting aggresome-formation and autophagy-impairment. Moreover, our data also demonstrate that both WPSE and nicotine exposure significantly (p<0.05) elevates Ub-LC3β co-localization to aggresome-bodies while inducing Ub-p62 co-expression/accumulation, verifying autophagy-impairment. We also found that WPSE and nicotine exposure impacts Beas2b cell viability by significantly (p<0.05) inducing cellular apoptosis/senescence via ROS-activation, as it could be controlled by cysteamine, which is known to have an anti-oxidant property. For murine studies, C57BL/6 mice were administered with inhaled nicotine (intranasal, 500μg/mouse/day for 5 days), as an experimental model of non-combustible nicotine exposure. The inhaled nicotine exposure mediated oxidative-stress induces autophagy-impairment in the murine lungs as seen by significant (p<0.05, n=4) increase in the expression levels of nitrotyrosine protein-adduct (oxidative-stress marker, soluble-fraction) and Ub/p62/VCP (impaired-autophagy marker, insoluble-fraction). Overall, our data shows that nicotine, a common component of WPS, e-cigarette vapor and cigarette smoke, induces bronchial epithelial cell apoptosis and senescence via ROS mediated autophagy-impairment as a potential

  2. TMEM16A mediates the hypersecretion of mucus induced by Interleukin-13

    SciTech Connect

    Lin, Jiachen; Jiang, Youfan; Li, Li; Liu, Yanan; Tang, Hui; Jiang, Depeng

    2015-06-10

    Previous studies showed that the Ca{sup 2+}-activated Cl{sup −} channel (CaCC) was involved in the pathogenesis of mucus hypersecretion induced by Interleukin-13 (IL-13). However, the mechanisms underlying the process were unknown. Recently, transmembrane protein 16A (TMEM16A) was identified as the channel underlying the CaCC current. The aim of the current study was to investigate whether the TMEM16A channel is part of the mechanism underlying IL-13-induced mucus hypersecretion. We observed that both TMEM16A mRNA and protein expression were significantly up-regulated after treatment with IL-13 in human bronchial epithelial 16 (HBE 16) cells, which correlated with an increase in mucus production. Additionally, mucus hypersecretion in rat airways was induced by intratracheal instillation of IL-13 and similar increases were observed in the expression of TMEM16A mRNA and protein in the bronchial epithelium. Niflumic acid (NA), a selective antagonist of CaCC, markedly blocked IL-13-induced mucin (MUC) 5AC mRNA and protein production in vivo and in vitro. Further investigation with HBE16 cells revealed that TMEM16A overexpression clearly promoted mucus production, IκBα phosphorylation, and p65 accumulation in the nucleus. The loss of TMEM16A resulted in inhibition of mucus production, and the TMEM16A-mediated production of MUC5AC was significantly blocked by a nuclear factor-kappa B (NF-κB) inhibitor. Therefore, the TMEM16A channel acts upstream of NF-κB in the regulation of mucus production. This is the first demonstration that the TMEM16A-NF-κB pathway is positively involved in IL-13-induced mucus production, which provides novel insight into the molecular mechanism of mucin overproduction. - Highlights: • TMEM16A acts as downstream events of IL-13 signaling pathway. • Established the link between TMEM16A and mucus hypersecretion. • NF-κB activation might be responsible for TMEM16A mediated mucus secretion.

  3. Zeaxanthin induces Nrf2-mediated phase II enzymes in protection of cell death.

    PubMed

    Zou, X; Gao, J; Zheng, Y; Wang, X; Chen, C; Cao, K; Xu, J; Li, Y; Lu, W; Liu, J; Feng, Z

    2014-01-01

    Zeaxanthin (Zea) is a major carotenoid pigment contained in human retina, and its daily supplementation associated with lower risk of age-related macular degeneration. Despite known property of Zea as an antioxidant, its underlying molecular mechanisms of action remain poorly understood. In this study, we aim to study the regulation mechanism of Zea on phase II detoxification enzymes. In normal human retinal pigment epithelium cells, Zea promoted the nuclear translocation of NF-E2-related factor 2 (Nrf2) and induced mRNA and protein expression of phase II enzymes, the induction was suppressed by specific knockdown of Nrf2. Zea also effectively protected against tert-butyl hydroperoxide-induced mitochondrial dysfunction and apoptosis. Glutathione (GSH) as the most important antioxidant was also induced by Zea through Nrf2 activation in a time- and dose-dependent manner, whereas the protective effects of Zea were decimated by inhibition of GSH synthesis. Finally, Zea activated the PI3K/Akt and MAPK/ERK pathway, whereas only PI3K/Akt activation correlated with phase II enzymes induction and Zea protection. In further in vivo analyses, Zea showed effects of inducing phase II enzymes and increased GSH content, which contributed to the reduced lipid and protein peroxidation in the retina as well as the liver, heart, and serum of the Sprague-Dawley rats. For the first time, Zea is presented as a phase II enzymes inducer instead of being an antioxidant. By activating Nrf2-mediated phase II enzymes, Zea could enhance anti-oxidative capacity and prevent cell death both in vivo and in vitro. PMID:24810054

  4. Cholangiocyte N-Ras Protein Mediates Lipopolysaccharide-induced Interleukin 6 Secretion and Proliferation*

    PubMed Central

    O'Hara, Steven P.; Splinter, Patrick L.; Trussoni, Christy E.; Gajdos, Gabriella B.; Lineswala, Pooja N.; LaRusso, Nicholas F.

    2011-01-01

    Cholangiocytes, the epithelial cells lining the bile ducts in the liver, are periodically exposed to potentially injurious microbes and/or microbial products. As a result, cholangiocytes actively participate in microbe-associated, hepatic proinflammatory responses. We previously showed that infection of cultured human cholangiocytes with the protozoan parasite, Cryptosporidium parvum, or treatment with Gram-negative bacteria-derived LPS, activates NFκB in a myeloid differentiation 88 (MyD88)-dependent manner. Here, we describe a novel signaling pathway initiated by Toll-like receptors (TLRs) involving the small GTPase, Ras, that mediates cholangiocyte proinflammatory cytokine production and induction of cholangiocyte proliferation. Using cultured human cholangiocytes and a Ras activation assay, we found that agonists of plasma membrane TLRs (TLR 1, 2, 4, 5, and 6) rapidly (<10 min) activated N-Ras, but not other p21 Ras isoforms, resulting in the rapid (<15 min) phosphorylation of the downstream Ras effector, ERK1/2. RNA interference-induced depletion of TRAF6, a downstream effector of MyD88 and known activator of MAPK signaling, had no effect on N-Ras activation. Following N-Ras activation the proinflammatory cytokine, IL6, is rapidly secreted. Using a luciferase reporter, we demonstrated that LPS treatment induced IL6 promoter-driven luciferase which was suppressed using MEK/ERK pharmacologic inhibitors (PD98059 or U0126) and RNAi-induced depletion of N-Ras. Finally, we showed that LPS increased cholangiocyte proliferation (1.5-fold), which was inhibited by depletion of N-Ras; TLR agonist-induced proliferation was also inhibited following pretreatment with an IL6 receptor-blocking antibody. Together, our results support a novel signaling axis involving microbial activation of N-Ras likely involved in the cholangiocyte pathogen-induced proinflammatory response. PMID:21757746

  5. Adrenomedullin mediates tumor necrosis factor-α-induced responses in dorsal root ganglia in rats.

    PubMed

    Chen, Yajuan; Zhang, Yan; Huo, Yuanhui; Wang, Dongmei; Hong, Yanguo

    2016-08-01

    Adrenomedullin (AM), a member of the calcitonin gene-related peptide (CGRP) family, has been demonstrated to be a pain peptide. This study investigated the possible involvement of AM in tumor necrosis factor-alpha (TNF-α)-induced responses contributing to neuronal plasticity in the dorsal root ganglia (DRG). Exposure of the DRG explant cultures to TNF-α (5nM) for 48h upregulated the expression of AM mRNA. The treatment with TNF-α also increased the level of CGRP, CCL-2 and MMP-9 mRNA in the cultured DRG. This increase was attenuated by the co-treatment with the selective AM receptor antagonist AM22-52 (2μM). The blockade of AM receptors inhibited TNF-α-induced increase of the glial fibrillary acidic protein (GFAP), interleukin-1β (IL-1β), phosphorylated cAMP response element binding protein (pCREB) and nuclear factor kappa B (pNF-κB) proteins. On the other hand, the treatment with the AM receptor agonist AM1-50 (10nM) for 96h induced an increase in the level of GFAP, IL-1β, pCREB and pNF-κB proteins. The inhibition of AM activity did not change TNF-α-induced phosphorylation of extracellular signal-related kinase (pERK) while the treatment with AM1-50 still increased the level of pERK in the cultured DRG. Immunofluorescence assay showed the colocalization of AM-like immunoreactivity (IR) with TNF-α-IR in DRG neurons. The present study suggests that the increased AM receptor signaling mediated the many, but not all, TNF-α-induced activities, contributing to peripheral sensitization in neuropathic pain. PMID:27184601

  6. Pellino1-mediated TGF-β1 synthesis contributes to mechanical stress induced cardiac fibroblast activation.

    PubMed

    Song, Juan; Zhu, Yun; Li, Jiantao; Liu, Jiahao; Gao, Yun; Ha, Tuanzhu; Que, Linli; Liu, Li; Zhu, Guoqing; Chen, Qi; Xu, Yong; Li, Chuanfu; Li, Yuehua

    2015-02-01

    Activation of cardiac fibroblasts is a key event in the progression of cardiac fibrosis that leads to heart failure. However, the molecular mechanisms underlying mechanical stress-induced cardiac fibroblast activation are complex and poorly understood. This study demonstrates that Pellino1, an E3 ubiquitin ligase, was activated in vivo in pressure overloaded rat hearts and in cultured neonatal rat cardiac fibroblasts (NRCFs) exposed to mechanical stretch in vitro. Suppression of the expression and activity of Pellino1 by adenovirus-mediated delivery of shPellino1 (adv-shpeli1) attenuated pressure overload-induced cardiac dysfunction and cardiac hypertrophy and decreased cardiac fibrosis in rat hearts. Transfection of adv-shpeli1 also significantly attenuated mechanical stress-induced proliferation, differentiation and collagen synthesis in NRCFs. Pellino1 silencing also abrogated mechanical stretch-induced polyubiquitination of tumor necrosis factor-alpha receptor association factor-6 (TRAF6) and receptor-interacting protein 1 (RIP1) and consequently decreased the DNA binding activity of nuclear factor-kappa B (NF-κB) in NRCFs. In addition, Pellino1 silencing prevented stretch-induced activation of p38 and activator protein 1 (AP-1) binding activity in NRCFs. Chromatin Immunoprecipitation (ChIP) and luciferase reporter assays showed that Pellino1 silencing prevented the binding of NF-κB and AP-1 to the promoter region of transforming growth factor-β1 (TGF-β1) thus dampening TGF-β1 transactivation. Our data reveal a previously unrecognized role of Pellino1 in extracellular matrix deposition and cardiac fibroblast activation in response to mechanical stress and provides a novel target for treatment of cardiac fibrosis and heart failure. PMID:25446187

  7. GATA2 Mediates Thyrotropin-Releasing Hormone-Induced Transcriptional Activation of the Thyrotropin β Gene

    PubMed Central

    Ohba, Kenji; Sasaki, Shigekazu; Matsushita, Akio; Iwaki, Hiroyuki; Matsunaga, Hideyuki; Suzuki, Shingo; Ishizuka, Keiko; Misawa, Hiroko; Oki, Yutaka; Nakamura, Hirotoshi

    2011-01-01

    Thyrotropin-releasing hormone (TRH) activates not only the secretion of thyrotropin (TSH) but also the transcription of TSHβ and α-glycoprotein (αGSU) subunit genes. TSHβ expression is maintained by two transcription factors, Pit1 and GATA2, and is negatively regulated by thyroid hormone (T3). Our prior studies suggest that the main activator of the TSHβ gene is GATA2, not Pit1 or unliganded T3 receptor (TR). In previous studies on the mechanism of TRH-induced activation of the TSHβ gene, the involvements of Pit1 and TR have been investigated, but the role of GATA2 has not been clarified. Using kidney-derived CV1 cells and pituitary-derived GH3 and TαT1 cells, we demonstrate here that TRH signaling enhances GATA2-dependent activation of the TSHβ promoter and that TRH-induced activity is abolished by amino acid substitution in the GATA2-Zn finger domain or mutation of GATA-responsive element in the TSHβ gene. In CV1 cells transfected with TRH receptor expression plasmid, GATA2-dependent transactivation of αGSU and endothelin-1 promoters was enhanced by TRH. In the gel shift assay, TRH signal potentiated the DNA-binding capacity of GATA2. While inhibition by T3 is dominant over TRH-induced activation, unliganded TR or the putative negative T3-responsive element are not required for TRH-induced stimulation. Studies using GH3 cells showed that TRH-induced activity of the TSHβ promoter depends on protein kinase C but not the mitogen-activated protein kinase, suggesting that the signaling pathway is different from that in the prolactin gene. These results indicate that GATA2 is the principal mediator of the TRH signaling pathway in TSHβ expression. PMID:21533184

  8. Acid aspiration-induced lung injury in rabbits is mediated by interleukin-8-dependent mechanisms.

    PubMed Central

    Folkesson, H G; Matthay, M A; Hébert, C A; Broaddus, V C

    1995-01-01

    Acid aspiration lung injury may be mediated primarily by neutrophils recruited to the lung by acid-induced cytokines. We hypothesized that a major acid-induced cytokine was IL-8 and that a neutralizing anti-rabbit-IL-8 monoclonal antibody (ARIL8.2) would attenuate acid-induced lung injury in rabbits. Hydrochloric acid (pH = 1.5 in 1/3 normal saline) or 1/3 normal saline (4 ml/kg) was instilled into the lungs of ventilated, anesthetized rabbits. The rabbits were studied for 6 or 24 h. In acid-instilled rabbits without the anti-IL-8 monoclonal antibody, severe lung injury developed in the first 6 h; in the long-term experiments, all rabbits died with lung injury between 12 and 14 h. In acid-instilled rabbits given the anti-IL-8 monoclonal antibody (2 mg/kg, intravenously) either as pretreatment (5 min before the acid) or as treatment (1 h after the acid), acid-induced abnormalities in oxygenation and extravascular lung water were prevented and extravascular protein accumulation was reduced by 70%; in the long-term experiments, anti-IL-8 treatment similarly protected lung function throughout the 24-h period. The anti-IL-8 monoclonal antibody also significantly reduced air space neutrophil counts and IL-8 concentrations. This study establishes IL-8 as a critical cytokine for the development of acid-induced lung injury. Neutralization of IL-8 may provide the first useful therapy for this clinically important form of acute lung injury. Images PMID:7615779

  9. TRAF3IP2 mediates aldosterone/salt-induced cardiac hypertrophy and fibrosis.

    PubMed

    Sakamuri, Siva S V P; Valente, Anthony J; Siddesha, Jalahalli M; Delafontaine, Patrice; Siebenlist, Ulrich; Gardner, Jason D; Bysani, Chandrasekar

    2016-07-01

    Aberrant activation of the renin-angiotensin-aldosterone system (RAAS) contributes to adverse cardiac remodeling and eventual failure. Here we investigated whether TRAF3 Interacting Protein 2 (TRAF3IP2), a redox-sensitive cytoplasmic adaptor molecule and an upstream regulator of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), mediates aldosterone-induced cardiac hypertrophy and fibrosis. Wild type (WT) and TRAF3IP2-null mice were infused with aldosterone (0.2 mg/kg/day) for 4 weeks along with 1%NaCl in drinking water. Aldosterone/salt, but not salt alone, upregulated TRAF3IP2 expression in WT mouse hearts. Further, aldosterone elevated blood pressure to a similar extent in both WT and TRAF3IP2-null groups. However, TRAF3IP2 gene deletion attenuated aldosterone/salt-induced (i) p65 and c-Jun activation, (ii) extracellular matrix (collagen Iα1 and collagen IIIα1), matrix metalloproteinase (MMP2), lysyl oxidase (LOX), inflammatory cytokine (IL-6 and IL-18), chemokine (CXCL1 and CXCL2), and adhesion molecule (ICAM1) mRNA expression in hearts, (iii) IL-6, IL-18, and MMP2 protein levels, (iv) systemic IL-6 and IL-18 levels, and (iv) cardiac hypertrophy and fibrosis. These results indicate that TRAF3IP2 is a critical signaling intermediate in aldosterone/salt-induced myocardial hypertrophy and fibrosis, and thus a potential therapeutic target in hypertensive heart disease. PMID:27040306

  10. Inflammation-mediated skin tumorigenesis induced by epidermal c-Fos

    PubMed Central

    Briso, Eva M.; Guinea-Viniegra, Juan; Bakiri, Latifa; Rogon, Zbigniew; Petzelbauer, Peter; Eils, Roland; Wolf, Ronald; Rincón, Mercedes; Angel, Peter; Wagner, Erwin F.

    2013-01-01

    Skin squamous cell carcinomas (SCCs) are the second most prevalent skin cancers. Chronic skin inflammation has been associated with the development of SCCs, but the contribution of skin inflammation to SCC development remains largely unknown. In this study, we demonstrate that inducible expression of c-fos in the epidermis of adult mice is sufficient to promote inflammation-mediated epidermal hyperplasia, leading to the development of preneoplastic lesions. Interestingly, c-Fos transcriptionally controls mmp10 and s100a7a15 expression in keratinocytes, subsequently leading to CD4 T-cell recruitment to the skin, thereby promoting epidermal hyperplasia that is likely induced by CD4 T-cell-derived IL-22. Combining inducible c-fos expression in the epidermis with a single dose of the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) leads to the development of highly invasive SCCs, which are prevented by using the anti-inflammatory drug sulindac. Moreover, human SCCs display a correlation between c-FOS expression and elevated levels of MMP10 and S100A15 proteins as well as CD4 T-cell infiltration. Our studies demonstrate a bidirectional cross-talk between premalignant keratinocytes and infiltrating CD4 T cells in SCC development. Therefore, targeting inflammation along with the newly identified targets, such as MMP10 and S100A15, represents promising therapeutic strategies to treat SCCs. PMID:24029918

  11. The unfolded protein response mediates reversible tau phosphorylation induced by metabolic stress

    PubMed Central

    van der Harg, J M; Nölle, A; Zwart, R; Boerema, A S; van Haastert, E S; Strijkstra, A M; Hoozemans, J JM; Scheper, W

    2014-01-01

    The unfolded protein response (UPR) is activated in neurodegenerative tauopathies such as Alzheimer's disease (AD) in close connection with early stages of tau pathology. Metabolic disturbances are strongly associated with increased risk for AD and are a potent inducer of the UPR. Here, we demonstrate that metabolic stress induces the phosphorylation of endogenous tau via activation of the UPR. Strikingly, upon restoration of the metabolic homeostasis, not only the levels of the UPR markers pPERK, pIRE1α and BiP, but also tau phosphorylation are reversed both in cell models as well as in torpor, a physiological hypometabolic model in vivo. Intervention in the UPR using the global UPR inhibitor TUDCA or a specific small-molecule inhibitor of the PERK signaling pathway, inhibits the metabolic stress-induced phosphorylation of tau. These data support a role for UPR-mediated tau phosphorylation as part of an adaptive response to metabolic stress. Failure to restore the metabolic homeostasis will lead to prolonged UPR activation and tau phosphorylation, and may thus contribute to AD pathogenesis. We demonstrate that the UPR is functionally involved in the early stages of tau pathology. Our data indicate that targeting of the UPR may be employed for early intervention in tau-related neurodegenerative diseases. PMID:25165879

  12. The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling

    SciTech Connect

    Munoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Diaz-Araya, Guillermo; Hidalgo, Cecilia; Lavandero, Sergio

    2009-10-09

    Myocyte enhancer factor 2C (MEF2C) plays an important role in cardiovascular development and is a key transcription factor for cardiac hypertrophy. Here, we describe MEF2C regulation by insulin-like growth factor-1 (IGF-1) and its role in IGF-1-induced cardiac hypertrophy. We found that IGF-1 addition to cultured rat cardiomyocytes activated MEF2C, as evidenced by its increased nuclear localization and DNA binding activity. IGF-1 stimulated MEF2 dependent-gene transcription in a time-dependent manner, as indicated by increased MEF2 promoter-driven reporter gene activity; IGF-1 also induced p38-MAPK phosphorylation, while an inhibitor of p38-MAPK decreased both effects. Additionally, inhibitors of phosphatidylinositol 3-kinase and calcineurin prevented IGF-1-induced MEF2 transcriptional activity. Via MEF2C-dependent signaling, IGF-1 also stimulated transcription of atrial natriuretic factor and skeletal {alpha}-actin but not of fos-lux reporter genes. These novel data suggest that MEF2C activation by IGF-1 mediates the pro-hypertrophic effects of IGF-1 on cardiac gene expression.

  13. Insulin signalling mediates the response to male-induced harm in female Drosophila melanogaster.

    PubMed

    Sepil, Irem; Carazo, Pau; Perry, Jennifer C; Wigby, Stuart

    2016-01-01

    Genetic manipulations in nutrient-sensing pathways are known to both extend lifespan and modify responses to environmental stressors (e.g., starvation, oxidative and thermal stresses), suggesting that similar mechanisms regulate lifespan and stress resistance. However, despite being a key factor reducing female lifespan and affecting female fitness, male-induced harm has rarely been considered as a stressor mediated by nutrient sensing pathways. We explored whether a lifespan-extending manipulation also modifies female resistance to male-induced harm. To do so, we used long-lived female Drosophila melanogaster that had their insulin signalling pathway downregulated by genetically ablating the median neurosecretory cells (mNSC). We varied the level of exposure to males for control and ablated females and tested for interacting effects on female lifespan and fitness. As expected, we found that lifespan significantly declined with exposure to males. However, mNSC-ablated females maintained significantly increased lifespan across all male exposure treatments. Furthermore, lifespan extension and relative fitness of mNSC-ablated females were maximized under intermediate exposure to males, and minimized under low and high exposure to males. Overall, our results suggest that wild-type levels of insulin signalling reduce female susceptibility to male-induced harm under intense sexual conflict, and may also protect females when mating opportunities are sub-optimally low. PMID:27457757

  14. Myo1c binding to submembrane actin mediates insulin-induced tethering of GLUT4 vesicles

    PubMed Central

    Boguslavsky, Shlomit; Chiu, Tim; Foley, Kevin P.; Osorio-Fuentealba, Cesar; Antonescu, Costin N.; Bayer, K. Ulrich; Bilan, Philip J.; Klip, Amira

    2012-01-01

    GLUT4-containing vesicles cycle between the plasma membrane and intracellular compartments. Insulin promotes GLUT4 exocytosis by regulating GLUT4 vesicle arrival at the cell periphery and its subsequent tethering, docking, and fusion with the plasma membrane. The molecular machinery involved in GLUT4 vesicle tethering is unknown. We show here that Myo1c, an actin-based motor protein that associates with membranes and actin filaments, is required for insulin-induced vesicle tethering in muscle cells. Myo1c was found to associate with both mobile and tethered GLUT4 vesicles and to be required for vesicle capture in the total internal reflection fluorescence (TIRF) zone beneath the plasma membrane. Myo1c knockdown or overexpression of an actin binding–deficient Myo1c mutant abolished insulin-induced vesicle immobilization, increased GLUT4 vesicle velocity in the TIRF zone, and prevented their externalization. Conversely, Myo1c overexpression immobilized GLUT4 vesicles in the TIRF zone and promoted insulin-induced GLUT4 exposure to the extracellular milieu. Myo1c also contributed to insulin-dependent actin filament remodeling. Thus we propose that interaction of vesicular Myo1c with cortical actin filaments is required for insulin-mediated tethering of GLUT4 vesicles and for efficient GLUT4 surface delivery in muscle cells. PMID:22918957

  15. Myo1c binding to submembrane actin mediates insulin-induced tethering of GLUT4 vesicles.

    PubMed

    Boguslavsky, Shlomit; Chiu, Tim; Foley, Kevin P; Osorio-Fuentealba, Cesar; Antonescu, Costin N; Bayer, K Ulrich; Bilan, Philip J; Klip, Amira

    2012-10-01

    GLUT4-containing vesicles cycle between the plasma membrane and intracellular compartments. Insulin promotes GLUT4 exocytosis by regulating GLUT4 vesicle arrival at the cell periphery and its subsequent tethering, docking, and fusion with the plasma membrane. The molecular machinery involved in GLUT4 vesicle tethering is unknown. We show here that Myo1c, an actin-based motor protein that associates with membranes and actin filaments, is required for insulin-induced vesicle tethering in muscle cells. Myo1c was found to associate with both mobile and tethered GLUT4 vesicles and to be required for vesicle capture in the total internal reflection fluorescence (TIRF) zone beneath the plasma membrane. Myo1c knockdown or overexpression of an actin binding-deficient Myo1c mutant abolished insulin-induced vesicle immobilization, increased GLUT4 vesicle velocity in the TIRF zone, and prevented their externalization. Conversely, Myo1c overexpression immobilized GLUT4 vesicles in the TIRF zone and promoted insulin-induced GLUT4 exposure to the extracellular milieu. Myo1c also contributed to insulin-dependent actin filament remodeling. Thus we propose that interaction of vesicular Myo1c with cortical actin filaments is required for insulin-mediated tethering of GLUT4 vesicles and for efficient GLUT4 surface delivery in muscle cells. PMID:22918957

  16. Hapten-Induced Contact Hypersensitivity, Autoimmune Reactions, and Tumor Regression: Plausibility of Mediating Antitumor Immunity

    PubMed Central

    Erkes, Dan A.; Selvan, Senthamil R.

    2014-01-01

    Haptens are small molecule irritants that bind to proteins and elicit an immune response. Haptens have been commonly used to study allergic contact dermatitis (ACD) using animal contact hypersensitivity (CHS) models. However, extensive research into contact hypersensitivity has offered a confusing and intriguing mechanism of allergic reactions occurring in the skin. The abilities of haptens to induce such reactions have been frequently utilized to study the mechanisms of inflammatory bowel disease (IBD) to induce autoimmune-like responses such as autoimmune hemolytic anemia and to elicit viral wart and tumor regression. Hapten-induced tumor regression has been studied since the mid-1900s and relies on four major concepts: (1) ex vivo haptenation, (2) in situ haptenation, (3) epifocal hapten application, and (4) antigen-hapten conjugate injection. Each of these approaches elicits unique responses in mice and humans. The present review attempts to provide a critical appraisal of the hapten-mediated tumor treatments and offers insights for future development of the field. PMID:24949488

  17. Hydroxyurea induces hydroxyl radical-mediated cell death in Escherichia coli

    PubMed Central

    Davies, Bryan W.; Kohanski, Michael A.; Simmons, Lyle A.; Winkler, Jonathan A.; Collins, James J.; Walker, Graham C.

    2010-01-01

    SUMMARY Hydroxyurea (HU) specifically inhibits class I ribonucleotide reductase (RNR), depleting dNTP pools and leading to replication fork arrest. While HU inhibition of RNR has been recognized for decades, the mechanism by which it leads to cell death remains unknown. To investigate the mechanism of HU-induced cell death we used a systems-level approach to determine the genomic and physiological responses of E. coli to HU treatment. Our results suggest a model by which HU treatment rapidly induces a set of protective responses to manage genomic instability in the majority of the cell population. Continued HU stress activates iron uptake as well as the toxins MazF and RelE whose activity causes the synthesis of incompletely translated proteins and stimulation of the envelope stress response system. These effects alter the properties of one of the cell’s two terminal cytochrome oxidases in the electron transport chain, causing an increase in the production of superoxide. The increased superoxide production from the respiratory chain together with the increased iron uptake fuels the formation of hydroxyl radicals that contribute to HU-induced cell death. This work significantly expands our understanding of HU-mediated cell death and more broadly suggests a pathway whereby replication fork arrest leads to cell death. PMID:20005847

  18. Adenylyl cyclase 6 mediates loading-induced bone adaptation in vivo.

    PubMed

    Lee, Kristen L; Hoey, David A; Spasic, Milos; Tang, Tong; Hammond, H Kirk; Jacobs, Christopher R

    2014-03-01

    Primary cilia are single, nonmotile, antenna-like structures extending from the apical membrane of most mammalian cells. They may mediate mechanotransduction, the conversion of external mechanical stimuli into biochemical intracellular signals. Previously we demonstrated that adenylyl cyclase 6 (AC6), a membrane-bound enzyme enriched in primary cilia of MLO-Y4 osteocyte-like cells, may play a role in a primary cilium-dependent mechanism of osteocyte mechanotransduction in vitro. In this study, we determined whether AC6 deletion impairs loading-induced bone formation in vivo. Skeletally mature mice with a global knockout of AC6 exhibited normal bone morphology and responded to osteogenic chemical stimuli similar to wild-type mice. Following ulnar loading over 3 consecutive days, bone formation parameters were assessed using dynamic histomorphometry. Mice lacking AC6 formed significantly less bone than control animals (41% lower bone formation rate). Furthermore, there was an attenuated flow-induced increase in COX-2 mRNA expression levels in primary bone cells isolated from AC6 knockout mice compared to controls (1.3±0.1- vs. 2.6±0.2-fold increase). Collectively, these data indicate that AC6 plays a role in loading-induced bone adaptation, and these findings are consistent with our previous studies implicating primary cilia and AC6 in a novel mechanism of osteocyte mechanotransduction. PMID:24277577

  19. Curcumin induces apoptosis through the mitochondria-mediated apoptotic pathway in HT-29 cells*

    PubMed Central

    Wang, Jin-bo; Qi, Li-li; Zheng, Shui-di; Wu, Tian-xing

    2009-01-01

    Objective: To investigate the effects of curcumin on release of cytochrome c and expressions of Bcl-2, Bax, Bad, Bcl-xL, caspase-3, poly ADP-ribose polymerase (PARP), and survivin of HT-29 cells. Methods: HT-29 cells were treated with curcumin (0~80 μmol/L) for 24 h. The release of cytochrome c from the mitochondria and the apoptosis-related proteins Bax, Bcl-2, Bcl-xL, Bad, caspase-3, PARP, and survivin were determined by Western blot analysis and their mRNA expressions by reverse transcriptase-polymerase chain reaction (RT-PCR). Results: Curcumin significantly induced the growth inhibition and apoptosis of HT-29 cells. A decrease in expressions of Bcl-2, Bcl-xL and survivin was observed after exposure to 10~80 μmol/L curcumin, while the levels of Bax and Bad increased in the curcumin-treated cells. Curcumin also induced the release of cytochrome c, the activation of caspase-3, and the cleavage of PARP in a dose-dependent manner. Conclusion: These data suggest that curcumin induced the HT-29 cell apoptosis possibly via the mitochondria-mediated pathway. PMID:19235267

  20. Exchange factors directly activated by cAMP mediate melanocortin 4 receptor-induced gene expression

    PubMed Central

    Glas, Evi; Mückter, Harald; Gudermann, Thomas; Breit, Andreas

    2016-01-01

    Gs protein-coupled receptors regulate many vital body functions by activation of cAMP response elements (CRE) via cAMP-dependent kinase A (PKA)-mediated phosphorylation of the CRE binding protein (CREB). Melanocortin 4 receptors (MC4R) are prototypical Gs-coupled receptors that orchestrate the hypothalamic control of food-intake and metabolism. Remarkably, the significance of PKA for MC4R-induced CRE-dependent transcription in hypothalamic cells has not been rigorously interrogated yet. In two hypothalamic cell lines, we observed that blocking PKA activity had only weak or no effects on reporter gene expression. In contrast, inhibitors of exchange factors directly activated by cAMP-1/2 (EPAC-1/2) mitigated MC4R-induced CRE reporter activation and mRNA induction of the CREB-dependent genes c-fos and thyrotropin-releasing hormone. Furthermore, we provide first evidence that extracellular-regulated kinases-1/2 (ERK-1/2) activated by EPACs and not PKA are the elusive CREB kinases responsible for MC4R-induced CREB/CRE activation in hypothalamic cells. Overall, these data emphasize the pivotal role of EPACs rather than PKA in hypothalamic gene expression elicited by a prototypical Gs-coupled receptor. PMID:27612207

  1. Sox9 mediates Notch1-induced mesenchymal features in lung adenocarcinoma

    PubMed Central

    Capaccione, Kathleen M.; Hong, Xuehui; Morgan, Katherine M.; Liu, Wenyu; Bishop, Michael J.; Liu, LianXin; Markert, Elke; Deen, Malik; Minerowicz, Christine; Bertino, Joseph R.; Allen, Thaddeus; Pine, Sharon R.

    2014-01-01

    Sox9 has gained increasing importance both functionally and as a prognostic factor in cancer. We demonstrate a functional role for Sox9 in inducing a mesenchymal phenotype in lung ADC. We show that Sox9 mRNA and protein are overexpressed in lung ADC, particularly those with KRAS mutations. Sox9 expression correlated with the Notch target gene Hes1, and numerous other Notch pathway components. We observed that Sox9 is a potent inducer of lung cancer cell motility and invasion, and a negative regulator of E-cadherin, a key protein that is lost during epithelial-mesenchymal transition (EMT). Moreover, we show that Notch1 signaling directly regulates Sox9 expression through a SOX9 promoter binding site, independently of the TGF-β pathway, and that Sox9 participates in Notch-1 induced cell motility, cell invasion, and loss of E-cadherin expression. Together, the results identify a new functional role for a Notch1-Sox9 signaling axis in lung ADC that may explain the correlation of Sox9 with tumor progression, higher tumor grade, and poor lung cancer survival. In addition to Notch and TGF-β, Sox9 also acts downstream of NF-κB and Wnt/β-catenin signaling. Thus, Sox9 could potentially act as a hub to mediate cross-talk among key oncogenic pathways in lung ADC. Targeting Sox9 expression or transcriptional activity could potentially reduce resistance to targeted therapy for lung ADC caused by pathway redundancy. PMID:25004243

  2. Inflammation-mediated skin tumorigenesis induced by epidermal c-Fos.

    PubMed

    Briso, Eva M; Guinea-Viniegra, Juan; Bakiri, Latifa; Rogon, Zbigniew; Petzelbauer, Peter; Eils, Roland; Wolf, Ronald; Rincón, Mercedes; Angel, Peter; Wagner, Erwin F

    2013-09-15

    Skin squamous cell carcinomas (SCCs) are the second most prevalent skin cancers. Chronic skin inflammation has been associated with the development of SCCs, but the contribution of skin inflammation to SCC development remains largely unknown. In this study, we demonstrate that inducible expression of c-fos in the epidermis of adult mice is sufficient to promote inflammation-mediated epidermal hyperplasia, leading to the development of preneoplastic lesions. Interestingly, c-Fos transcriptionally controls mmp10 and s100a7a15 expression in keratinocytes, subsequently leading to CD4 T-cell recruitment to the skin, thereby promoting epidermal hyperplasia that is likely induced by CD4 T-cell-derived IL-22. Combining inducible c-fos expression in the epidermis with a single dose of the carcinogen 7,12-dimethylbenz(a)anthracene (DMBA) leads to the development of highly invasive SCCs, which are prevented by using the anti-inflammatory drug sulindac. Moreover, human SCCs display a correlation between c-FOS expression and elevated levels of MMP10 and S100A15 proteins as well as CD4 T-cell infiltration. Our studies demonstrate a bidirectional cross-talk between premalignant keratinocytes and infiltrating CD4 T cells in SCC development. Therefore, targeting inflammation along with the newly identified targets, such as MMP10 and S100A15, represents promising therapeutic strategies to treat SCCs. PMID:24029918

  3. NADPH oxidase mediates radiation-induced oxidative stress in rat brain microvascular endothelial cells.

    PubMed

    Collins-Underwood, J Racquel; Zhao, Weiling; Sharpe, Jessica G; Robbins, Mike E

    2008-09-15

    The need to both understand and minimize the side effects of brain irradiation is heightened by the ever-increasing number of patients with brain metastases that require treatment with whole brain irradiation (WBI); some 200,000 cancer patients/year receive partial or WBI. At the present time, there are no successful treatments for radiation-induced brain injury, nor are there any known effective preventive strategies. Data support a role for chronic oxidative stress in radiation-induced late effects. However, the pathogenic mechanism(s) involved remains unknown. One candidate source of reactive oxygen species (ROS) is nicotinamide adenosine dinucleotide phosphate (NADPH) oxidase, which converts molecular oxygen (O(2)) to the superoxide anion (O(2)(-)) on activation. We hypothesize that brain irradiation leads to activation of NADPH oxidase. We report that irradiating rat brain microvascular endothelial cells in vitro leads to increased (i) intracellular ROS generation, (ii) activation of the transcription factor NFkappaB, (iii) expression of ICAM-1 and PAI-1, and (iv) expression of Nox4, p22(phox), and p47(phox). Pharmacologic and genetic inhibition of NADPH oxidase blocked the radiation-mediated upregulation of intracellular ROS, activation of NFkappaB, and upregulation of ICAM-1 and PAI-1. These results suggest that activation of NADPH oxidase may play a role in radiation-induced oxidative stress. PMID:18640264

  4. RhoA and ROCK mediate histamine-induced vascular leakage and anaphylactic shock

    PubMed Central

    Mikelis, Constantinos M.; Simaan, May; Ando, Koji; Fukuhara, Shigetomo; Sakurai, Atsuko; Amornphimoltham, Panomwat; Masedunskas, Andrius; Weigert, Roberto; Chavakis, Triantafyllos; Adams, Ralf; Offermanns, Stefan; Mochizuki, Naoki; Zheng, Yi; Gutkind, J. Silvio

    2015-01-01

    Histamine-induced vascular leakage is an integral component of many highly prevalent human diseases, including allergies, asthma, and anaphylaxis. Yet, how histamine induces the disruption of the endothelial barrier is not well defined. By using genetically modified animal models, pharmacologic inhibitors, and a synthetic biology approach, here we show that the small GTPase RhoA mediates histamine-induced vascular leakage. Histamine causes the rapid formation of focal adherens junctions, disrupting the endothelial barrier by acting on H1R Gαq-coupled receptors, which is blunted in endothelial Gαq/11 KO mice. Interfering with RhoA and ROCK function abolishes endothelial permeability, while phospholipase Cβ plays a limited role. Moreover, endothelial-specific RhoA gene deletion prevents vascular leakage and passive cutaneous anaphylaxis in vivo, and ROCK inhibitors protect from lethal systemic anaphylaxis. This study supports a key role for the RhoA signaling circuitry in vascular permeability, thereby identifying novel pharmacological targets for many human diseases characterized by aberrant vascular leakage. PMID:25857352

  5. Nicotine-induced acute hyperactivity is mediated by dopaminergic system in a sexually dimorphic manner.

    PubMed

    Zhang, Yunpeng; Guo, Jing; Guo, Aike; Li, Yan

    2016-09-22

    Short-term exposure to nicotine induces positive effects in mice, monkeys and humans, including mild euphoria, hyperactivity, and enhanced cognition. However, the underlying neural basis and molecular mechanisms for these effects remain poorly understood. Here, using a video recording system, we find that acute nicotine administration induces locomotor hyperactivity in Drosophila, similar to observations made in higher model organisms. Suppressing dopaminergic neurons or down-regulating dopamine 1-like receptor (DopR) abolishes this acute nicotine response, but surprisingly, does so only in male flies. Using a GFP reconstitution across synaptic partners (GRASP) approach, we show that dopaminergic neurons possess potential synaptic connections with acetylcholinergic neurons in wide regions of the brain. Furthermore, dopaminergic neurons are widely activated upon nicotine perfusion in both sexes, while the response curve differs significantly between the sexes. Moreover, knockdown of the β1 nicotine acetylcholine receptor (nAChR) in dopaminergic neurons abolishes the acute nicotine response only in male flies, while panneural knock-down occurs in both sexes. Taken together, our results reveal that in fruit flies, dopaminergic neurons mediate nicotine-induced acute locomotor hyperactivity in a sexually dimorphic manner, and Drosophila β1 nAChR subunit plays a crucial role in this nicotine response. These findings provide important insights into the molecular and neural basis of acute nicotine effects, and the underlying mechanisms may play conserved roles across species. PMID:27365175

  6. l-Cystathionine Inhibits the Mitochondria-Mediated Macrophage Apoptosis Induced by Oxidized Low Density Lipoprotein

    PubMed Central

    Zhu, Mingzhu; Du, Junbao; Chen, Siyao; Liu, Angie Dong; Holmberg, Lukas; Chen, Yonghong; Zhang, Chunyu; Tang, Chaoshu; Jin, Hongfang

    2014-01-01

    This study was designed to investigate the regulatory role of l-cystathionine in human macrophage apoptosis induced by oxidized low density lipoprotein (ox-LDL) and its possible mechanisms. THP-1 cells were induced with phorbol 12-myristate 13-acetate (PMA) and differentiated into macrophages. Macrophages were incubated with ox-LDL after pretreatment with l-cystathionine. Superoxide anion, apoptosis, mitochondrial membrane potential, and mitochondrial permeability transition pore (MPTP) opening were examined. Caspase-9 activities and expression of cleaved caspase-3 were measured. The results showed that compared with control group, ox-LDL treatment significantly promoted superoxide anion generation, release of cytochrome c (cytc) from mitochondrion into cytoplasm, caspase-9 activities, cleavage of caspase-3, and cell apoptosis, in addition to reduced mitochondrial membrane potential as well as increased MPTP opening. However, 0.3 and 1.0 mmol/L l-cystathionine significantly reduced superoxide anion generation, increased mitochondrial membrane potential, and markedly decreased MPTP opening in ox-LDL + l-cystathionine macrophages. Moreover, compared to ox-LDL treated-cells, release of cytc from mitochondrion into cytoplasm, caspase-9 activities, cleavage of caspase-3, and apoptosis levels in l-cystathionine pretreated cells were profoundly attenuated. Taken together, our results suggested that l-cystathionine could antagonize mitochondria-mediated human macrophage apoptosis induced by ox-LDL via inhibition of cytc release and caspase activation. PMID:25514411

  7. Insulin signalling mediates the response to male-induced harm in female Drosophila melanogaster

    PubMed Central

    Sepil, Irem; Carazo, Pau; Perry, Jennifer C.; Wigby, Stuart

    2016-01-01

    Genetic manipulations in nutrient-sensing pathways are known to both extend lifespan and modify responses to environmental stressors (e.g., starvation, oxidative and thermal stresses), suggesting that similar mechanisms regulate lifespan and stress resistance. However, despite being a key factor reducing female lifespan and affecting female fitness, male-induced harm has rarely been considered as a stressor mediated by nutrient sensing pathways. We explored whether a lifespan-extending manipulation also modifies female resistance to male-induced harm. To do so, we used long-lived female Drosophila melanogaster that had their insulin signalling pathway downregulated by genetically ablating the median neurosecretory cells (mNSC). We varied the level of exposure to males for control and ablated females and tested for interacting effects on female lifespan and fitness. As expected, we found that lifespan significantly declined with exposure to males. However, mNSC-ablated females maintained significantly increased lifespan across all male exposure treatments. Furthermore, lifespan extension and relative fitness of mNSC-ablated females were maximized under intermediate exposure to males, and minimized under low and high exposure to males. Overall, our results suggest that wild-type levels of insulin signalling reduce female susceptibility to male-induced harm under intense sexual conflict, and may also protect females when mating opportunities are sub-optimally low. PMID:27457757

  8. SOD2 Mediates Amifostine-Induced Protection against Glutamate in PC12 Cells

    PubMed Central

    Jia, Ji; Zhang, Lei; Shi, Xiaolei; Wu, Mingchun; Zhou, Xiang; Liu, Xiaonan; Huo, Tingting

    2016-01-01

    Background. Cytoprotectant amifostine attenuates radiation-induced oxidative injury by increasing intracellular manganese superoxide dismutase (SOD2) in peripheral tissue. However, whether amifostine could protect neuronal cells against oxidative injury has not been reported. The purpose of this study is to explore the protection of amifostine in PC12 cells. Methods. PC12 cells exposed to glutamate were used to mimic neuronal oxidative injury. SOD assay kit was taken to evaluate intracellular Cu/Zn SOD (SOD1) and SOD2 activities; western blot analysis and immunofluorescence staining were performed to investigate SOD2 protein expression; MTT, lactate dehydrogenase (LDH), release and cell morphology were used to evaluate cell injury degree, and apoptotic rate and cleaved caspase-3 expression were taken to assess apoptosis; mitochondrial superoxide production, intracellular reactive oxygen species (ROS), and glutathione (GSH) and catalase (CAT) levels were evaluated by reagent kits. Results. Amifostine increased SOD2 activity and expression, decreased cell injury and apoptosis, reduced mitochondrial superoxide production and intracellular ROS generation, and restored intracellular GSH and CAT levels in PC12 cells exposed to glutamate. SOD2-siRNA, however, significantly reversed the amifostine-induced cytoprotective and antioxidative actions. Conclusion. SOD2 mediates amifostine-induced protection in PC12 cells exposed to glutamate. PMID:26770652

  9. Mitochondrial Ca2+-induced Ca2+ Release Mediated by the Ca2+ Uniporter

    PubMed Central

    Montero, Mayte; Alonso, Maria Teresa; Albillos, Almudena; García-Sancho, Javier; Alvarez, Javier

    2001-01-01

    We have reported that a population of chromaffin cell mitochondria takes up large amounts of Ca2+ during cell stimulation. The present study focuses on the pathways for mitochondrial Ca2+ efflux. Treatment with protonophores before cell stimulation abolished mitochondrial Ca2+ uptake and increased the cytosolic [Ca2+] ([Ca2+]c) peak induced by the stimulus. Instead, when protonophores were added after cell stimulation, they did not modify [Ca2+]c kinetics and inhibited Ca2+ release from Ca2+-loaded mitochondria. This effect was due to inhibition of mitochondrial Na+/Ca2+ exchange, because blocking this system with CGP37157 produced no further effect. Increasing extramitochondrial [Ca2+]c triggered fast Ca2+ release from these depolarized Ca2+-loaded mitochondria, both in intact or permeabilized cells. These effects of protonophores were mimicked by valinomycin, but not by nigericin. The observed mitochondrial Ca2+-induced Ca2+ release response was insensitive to cyclosporin A and CGP37157 but fully blocked by ruthenium red, suggesting that it may be mediated by reversal of the Ca2+ uniporter. This novel kind of mitochondrial Ca2+-induced Ca2+ release might contribute to Ca2+ clearance from mitochondria that become depolarized during Ca2+ overload. PMID:11160823

  10. Sensory neuron-specific GPCRs Mrgprs are itch receptors mediating chloroquine-induced pruritus

    PubMed Central

    Liu, Qin; Tang, Zongxiang; Surdenikova, Lenka; Kim, Seungil; Patel, Kush N.; Kim, Andrew; Ru, Fei; Guan, Yun; Weng, Hao-Jui; Geng, Yixun; Undem, Bradley J.; Kollarik, Marian; Chen, Zhou-Feng; Anderson, David J.; Dong, Xinzhong

    2010-01-01

    SUMMARY The cellular and molecular mechanisms mediating histamine-independent itch in primary sensory neurons are largely unknown. Itch induced by chloroquine (CQ) is a common side-effect of this widely used anti-malarial drug. Here we show that Mrgprs, a family of G protein-coupled receptors expressed exclusively in peripheral sensory neurons, function as itch receptors. Mice lacking a cluster of Mrgpr genes display significant deficits in itch induced by CQ but not histamine. CQ directly excites sensory neurons in an Mrgpr-dependent manner. CQ specifically activates mouse MrgprA3 and human MrgprX1. Loss- and gain-of-function studies demonstrate that MrgprA3 is required for CQ responsiveness in mice. Furthermore, MrgprA3-expressing neurons respond to histamine and co-express Gastrin-Releasing Peptide, a peptide involved in itch sensation, and MrgprC11. Activation of these neurons with MrgprC11-specific agonist BAM8-22 induces itch in wild-type but not mutant mice. Therefore, Mrgprs may provide molecular access to itch-selective neurons and constitute novel targets for itch therapeutics. PMID:20004959

  11. Sensory neuron-specific GPCR Mrgprs are itch receptors mediating chloroquine-induced pruritus.

    PubMed

    Liu, Qin; Tang, Zongxiang; Surdenikova, Lenka; Kim, Seungil; Patel, Kush N; Kim, Andrew; Ru, Fei; Guan, Yun; Weng, Hao-Jui; Geng, Yixun; Undem, Bradley J; Kollarik, Marian; Chen, Zhou-Feng; Anderson, David J; Dong, Xinzhong

    2009-12-24

    The cellular and molecular mechanisms mediating histamine-independent itch in primary sensory neurons are largely unknown. Itch induced by chloroquine (CQ) is a common side effect of this widely used antimalarial drug. Here, we show that Mrgprs, a family of G protein-coupled receptors expressed exclusively in peripheral sensory neurons, function as itch receptors. Mice lacking a cluster of Mrgpr genes display significant deficits in itch induced by CQ but not histamine. CQ directly excites sensory neurons in an Mrgpr-dependent manner. CQ specifically activates mouse MrgprA3 and human MrgprX1. Loss- and gain-of-function studies demonstrate that MrgprA3 is required for CQ responsiveness in mice. Furthermore, MrgprA3-expressing neurons respond to histamine and coexpress gastrin-releasing peptide, a peptide involved in itch sensation, and MrgprC11. Activation of these neurons with the MrgprC11-specific agonist BAM8-22 induces itch in wild-type but not mutant mice. Therefore, Mrgprs may provide molecular access to itch-selective neurons and constitute novel targets for itch therapeutics. PMID:20004959

  12. Geldanamycin-induced degradation of Chk1 is mediated by proteasome

    SciTech Connect

    Nomura, M.; E-mail: nomura413jp@yahoo.co.jp; Nomura, N.; Yamashita, J.

    2005-09-30

    Checkpoint kinase 1 (Chk1) is a cell cycle regulator and a heat shock protein 90 (Hsp90) client. It is essential for cell proliferation and survival. In this report, we analyzed the mechanisms of Chk1 regulation in U87MG glioblastoma cells using Geldanamycin (GA), which interferes with the function of Hsp90. GA reduced Chk1 protein level but not its mRNA level in glioblastoma cells. Co-treatment with GA and cycloheximide (CHX), a protein synthesis inhibitor, induced a decrease of half-life of the Chk1 protein to 3 h and resulted in Chk1 down-regulation. CHX alone induced only 32% reduction of Chk1 protein even after 24 h. These findings indicated that reduction of Chk1 by GA was due to destabilization and degradation of the protein. In addition, GA-induced down-regulation of Chk1 was reversed by MG132, a specific proteasome inhibitor. And it was revealed that Chk1 was ubiquitinated by GA. These results have indicated that degradation of Chk1 by GA was mediated by the ubiquitin-proteasome pathway in U87MG glioblastoma cells.

  13. EF24 induces ROS-mediated apoptosis via targeting thioredoxin reductase 1 in gastric cancer cells

    PubMed Central

    Chen, Weiqian; Chen, Xi; Ying, Shilong; Feng, Zhiguo; Chen, Tongke; Ye, Qingqing; Wang, Zhe; Qiu, Chenyu; Yang, Shulin; Liang, Guang

    2016-01-01

    Gastric cancer (GC) is one of the leading causes of cancer mortality in the world, and finding novel agents for the treatment of advanced gastric cancer is of urgent need. Diphenyl difluoroketone (EF24), a molecule having structural similarity to curcumin, exhibits potent anti-tumor activities by arresting cell cycle and inducing apoptosis. Although EF24 demonstrates potent anticancer efficacy in numerous types of human cancer cells, the cellular targets of EF24 have not been fully defined. We report here that EF24 may interact with the thioredoxin reductase 1 (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme, to induce reactive oxygen species (ROS)-mediated apoptosis in human gastric cancer cells. By inhibiting TrxR1 activity and increasing intracellular ROS levels, EF24 induces a lethal endoplasmic reticulum stress in human gastric cancer cells. Importantly, knockdown of TrxR1 sensitizes cells to EF24 treatment. In vivo, EF24 treatment markedly reduces the TrxR1 activity and tumor cell burden, and displays synergistic lethality with 5-FU against gastric cancer cells. Targeting TrxR1 with EF24 thus discloses a previously unrecognized mechanism underlying the biological activity of EF24, and reveals that TrxR1 is a good target for gastric cancer therapy. PMID:26919110

  14. EF24 induces ROS-mediated apoptosis via targeting thioredoxin reductase 1 in gastric cancer cells.

    PubMed

    Zou, Peng; Xia, Yiqun; Chen, Weiqian; Chen, Xi; Ying, Shilong; Feng, Zhiguo; Chen, Tongke; Ye, Qingqing; Wang, Zhe; Qiu, Chenyu; Yang, Shulin; Liang, Guang

    2016-04-01

    Gastric cancer (GC) is one of the leading causes of cancer mortality in the world, and finding novel agents for the treatment of advanced gastric cancer is of urgent need. Diphenyl difluoroketone (EF24), a molecule having structural similarity to curcumin, exhibits potent anti-tumor activities by arresting cell cycle and inducing apoptosis. Although EF24 demonstrates potent anticancer effïcacy in numerous types of human cancer cells, the cellular targets of EF24 have not been fully defined. We report here that EF24 may interact with the thioredoxin reductase 1 (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme, to induce reactive oxygen species (ROS)-mediated apoptosis in human gastric cancer cells. By inhibiting TrxR1 activity and increasing intracellular ROS levels, EF24 induces a lethal endoplasmic reticulum stress in human gastric cancer cells. Importantly, knockdown of TrxR1 sensitizes cells to EF24 treatment. In vivo, EF24 treatment markedly reduces the TrxR1 activity and tumor cell burden, and displays synergistic lethality with 5-FU against gastric cancer cells. Targeting TrxR1 with EF24 thus discloses a previously unrecognized mechanism underlying the biological activity of EF24, and reveals that TrxR1 is a good target for gastric cancer therapy. PMID:26919110

  15. Mcl-1 protects prostate cancer cells from cell death mediated by chemotherapy-induced DNA damage.

    PubMed

    Reiner, Teresita; de Las Pozas, Alicia; Parrondo, Ricardo; Palenzuela, Deanna; Cayuso, William; Rai, Priyamvada; Perez-Stable, Carlos

    2015-01-01

    The anti-apoptotic protein Mcl-1 is highly expressed in castration-resistant prostate cancer (CRPC), resulting in resistance to apoptosis and association with poor prognosis. Although predominantly localized in the cytoplasm, there is evidence that Mcl-1 exhibits nuclear localization where it is thought to protect against DNA damage-induced cell death. The role of Mcl-1 in mediating resistance to chemotherapy-induced DNA damage in prostate cancer (PCa) is not known. We show in human PCa cell lines and in TRAMP, a transgenic mouse model of PCa, that the combination of the antimitotic agent ENMD-1198 (analog of 2-methoxyestradiol) with betulinic acid (BA, increases proteotoxic stress) targets Mcl-1 by increasing its proteasomal degradation, resulting in increased γH2AX (DNA damage) and apoptotic/necrotic cell death. Knockdown of Mcl-1 in CRPC cells leads to elevated γH2AX, DNA strand breaks, and cell death after treatment with 1198 + BA- or doxorubicin. Additional knockdowns in PC3 cells suggests that cytoplasmic Mcl-1 protects against DNA damage by blocking the mitochondrial release of apoptosis-inducing factor and thereby preventing its nuclear translocation and subsequent interaction with the cyclophilin A endonuclease. Overall, our results suggest that chemotherapeutic agents that target Mcl-1 will promote cell death in response to DNA damage, particularly in CRPC. PMID:26425662

  16. Poly (ADP-Ribose) Polymerase Mediates Diabetes-Induced Retinal Neuropathy

    PubMed Central

    Mohammad, Ghulam; Siddiquei, Mohammad Mairaj

    2013-01-01

    Retinal neuropathy is an early event in the development of diabetic retinopathy. One of the potential enzymes that are activated by oxidative stress in the diabetic retina is poly (ADP-ribose) polymerase (PARP). We investigated the effect of the PARP inhibitor 1,5-isoquinolinediol on the expression of the neurodegeneration mediators and markers in the retinas of diabetic rats. After two weeks of streptozotocin-induced diabetes, rats were treated with 1,5-isoquinolinediol (3 mg/kg/day). After 4 weeks of diabetes, the retinas were harvested and the levels of reactive oxygen species (ROS) were determined fluorometrically and the expressions of PARP, phosporylated-ERK1/2, BDNF, synaptophysin, glutamine synthetase (GS), and caspase-3 were determined by Western blot analysis. Retinal levels of ROS, PARP-1/2, phosphorylated ERK1/2, and cleaved caspase-3 were significantly increased, whereas the expressions of BDNF synaptophysin and GS were significantly decreased in the retinas of diabetic rats, compared to nondiabetic rats. Administration of 1,5-isoquinolinediol did not affect the metabolic status of the diabetic rats, but it significantly attenuated diabetes-induced upregulation of PARP, ROS, ERK1/2 phosphorylation, and cleaved caspase-3 and downregulation of BDNF, synaptophysin, and GS. These findings suggest a beneficial effect of the PARP inhibitor in increasing neurotrophic support and ameliorating early retinal neuropathy induced by diabetes. PMID:24347828

  17. Combination therapies in adjuvant with topical ALA-mediated photodynamic therapy for DMBA-induced hamster buccal pouch premalignant lesions

    NASA Astrophysics Data System (ADS)

    Yang, Deng-Fu; Hsu, Yih-Chih

    2012-03-01

    In Taiwan, oral cancer has becomes the fastest growth male cancer disease due to the betel nut chewing habit combing with smoking and alcohol-drinking lifestyle of people. In order to eliminate the systemic phototoxic effect of 5-aminolevulinic acid (ALA), this study was designed to use a topical ALA-mediated PDT for treatment of DMBA-induced hamster buccal pouch precancerous lesions. DMBA was applied to one of the buccal pouches of hamsters thrice a week for 10 to 12 weeks. Cancerous lesions were induced and proven by histological examination. These DMBA-induced cancerous lesions were used for testing the efficacy of topical ALA-mediated PDT. Before PDT, fluorescence spectroscopy was used to determine when ALA reached its peak level in the lesional epithelial cells after topical application of ALA gel. We found that ALA reached its peak level in precancerous lesions about 2.5 hrs after topical application of ALA gel. The cancerous lesions in hamsters were then treated with topical ALA -mediated PDT with light exposure dose of 150 J/cm2 using LED 635 nm fiber-guided light device. Visual examination demonstrated that adjuvant topical ALA -mediated PDT group has shown better therapeutic results in compared to those of non-adjuvant topical ALA-mediated PDT group for DMBA-induced hamster buccal pouch precancerous lesions.

  18. Intercellular Adhesion Molecule-1–Dependent Neutrophil Adhesion to Endothelial Cells Induces Caveolae-Mediated Pulmonary Vascular Hyperpermeability

    PubMed Central

    Hu, Guochang; Vogel, Stephen M.; Schwartz, David E.; Malik, Asrar B.; Minshall, Richard D.

    2009-01-01

    We investigated the role of caveolae in the mechanism of increased pulmonary vascular permeability and edema formation induced by the activation of polymorphonuclear neutrophils (PMNs). We observed that the increase in lung vascular permeability induced by the activation of PMNs required caveolin-1, the caveolae scaffold protein. The permeability increase induced by PMN activation was blocked in caveolin-1 knockout mice and by suppressing caveolin-1 expression in rats. The response was also dependent on Src phosphorylation of caveolin-1 known to activate caveolae-mediated endocytosis in endothelial cells. To address the role of PMN interaction with endothelial cells, we used an intercellular adhesion molecule (ICAM)-1 blocking monoclonal antibody. Preventing the ICAM-1–mediated PMN binding to endothelial cells abrogated Src phosphorylation of caveolin-1, as well as the increase in endothelial permeability. Direct ICAM-1 activation by crosslinking recapitulated these responses, suggesting that ICAM-1 activates caveolin-1 signaling responsible for caveolae-mediated endothelial hyperpermeability. Our results provide support for the novel concept that a large component of pulmonary vascular hyperpermeability induced by activation of PMNs adherent to the vessel wall is dependent on signaling via caveolin-1 and increased caveolae-mediated transcytosis. Thus, it is important to consider the role of the transendothelial vesicular permeability pathway that contributes to edema formation in developing therapeutic interventions against PMN-mediated inflammatory diseases such as acute lung injury. PMID:18511851

  19. Indirect decentralized repetitive control

    NASA Technical Reports Server (NTRS)

    Lee, Soo Cheol; Longman, Richard W.

    1993-01-01

    Learning control refers to controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented a theory of indirect decentralized learning control based on use of indirect adaptive control concepts employing simultaneous identification and control. This paper extends these results to apply to the indirect repetitive control problem in which a periodic (i.e., repetitive) command is given to a control system. Decentralized indirect repetitive control algorithms are presented that have guaranteed convergence to zero tracking error under very general conditions. The original motivation of the repetitive control and learning control fields was learning in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the desired trajectory. Decentralized repetitive control is natural for this application because the feedback control for link rotations is normally implemented in a decentralized manner, treating each link as if it is independent of the other links.

  20. Indirect microbial detection

    NASA Technical Reports Server (NTRS)

    Wilkins, J. R.

    1980-01-01

    Indirect method for detection of microbial growth utilizes flow of charged particles across barrier that physically separated growing cells from electrodes and measures resulting difference in potential between two platinum electrodes. Technique allows simplified noncontact monitoring of all growth in highly infectious cultures or in critical biochemical studies.