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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 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

  2. 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

  3. OH radicals from the indirect actions of X-rays induce cell lethality and mediate the majority of the oxygen enhancement effect.

    PubMed

    Hirayama, Ryoichi; Ito, Atsushi; Noguchi, Miho; Matsumoto, Yoshitaka; Uzawa, Akiko; Kobashi, Gen; Okayasu, Ryuichi; Furusawa, Yoshiya

    2013-11-01

    We examined OH radical-mediated indirect actions from X irradiation on cell killing in wild-type Chinese hamster ovary cell lines (CHO and AA8) under oxic and hypoxic conditions, and compared the contribution of direct and indirect actions under both conditions. The contribution of indirect action on cell killing can be estimated from the maximum degree of protection by dimethylsulfoxide, which suppresses indirect action by quenching OH radicals without affecting the direct action of X rays on cell killing. The contributions of indirect action on cell killing of CHO cells were 76% and 50% under oxic and hypoxic conditions, respectively, and those for AA8 cells were 85% and 47%, respectively. Therefore, the indirect action on cell killing was enhanced by oxygen during X irradiation in both cell lines tested. Oxygen enhancement ratios (OERs) at the 10% survival level (D10 or LD90) for CHO and AA8 cells were 2.68 ± 0.15 and 2.76 ± 0.08, respectively. OERs were evaluated separately for indirect and direct actions, which gave the values of 3.75 and 2.01 for CHO, and 4.11 and 1.32 for AA8 cells, respectively. Thus the generally accepted OER value of ∼3 is best understood as the average of the OER values for both indirect and direct actions. These results imply that both indirect and direct actions on cell killing require oxygen for the majority of lethal DNA damage, however, oxygen plays a larger role in indirect than for direct effects. Conversely, the lethal damage induced by the direct action of X rays are less affected by oxygen concentration.

  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. GABAergic mediation of indirect transsynaptic control over basal and spatial memory testing-induced activation of septo-hippocampal cholinergic activity in mice.

    PubMed

    Durkin, T P

    1992-09-28

    A neurochemical study of the transsynaptic interactions established between septal GABAergic interneurones and cholinergic septo-hippocampal neurones was conducted using mice. The effects of acute in vivo injections of either muscimol (20-500 ng/0.2 microliter), bicuculline (100 ng-1 micrograms/0.2 microliter) or saline vehicle (0.2 microliter) into the medial septum on septo-hippocampal cholinergic activity were evaluated using measures of hippocampal high affinity choline uptake at 30 min post-injection in two main groups of mice. The first (quiet control) remained in their home cages during the post-injection period whereas the second (active) were submitted, 10 min following injection to a 20-min period of spatial working memory testing in an 8-arm radial maze. Intraseptal injections of either muscimol or bicuculline produced significant (25-50%) inhibition of hippocampal cholinergic activity in quiet conditions (basal) as compared to intact or saline-injected mice. In the active groups, whereas memory testing induced significant cholinergic activation (+15-20%) in intact and saline injected mice at 30 s post-test no significant memory testing-induced activation was observed in either muscimol or bicuculline-injected mice at any dose. The role of septal GABAergic interneurones in the indirect transsynaptic control over the basal and activated states of septo-hippocampal cholinergic activity is discussed with respect to the concept that these complex neuronal interactions contribute to the physiological mechanisms involved in the modulation of working memory performance.

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

    NASA Astrophysics Data System (ADS)

    Yu, F.; Luo, G.; Liu, X.; Easter, R. C.; Ma, X.; Ghan, S. J.

    2012-12-01

    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 the IMN scheme into the Community Atmosphere Model version 5 (CAM5). Our simulations show that, compared to globally averaged results based on H2SO4-H2O 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 (SWCF) by 3.67 W m-2 (more negative) and longwave cloud forcing by 1.78 W m-2 (more positive), with large spatial variations. The effect of ionization on SWCF derived from this study (3.67 W m-2) is a factor of ~3 higher that of a previous study (1.15 W m-2) based on a different ion nucleation scheme and climate model. Based on the present CAM5 simulation, the 5-yr mean impacts of solar cycle induced changes in ionization rates on CCN and cloud forcing are small (~-0.02 W m-2) but have larger inter-annual (from -0.18 to 0.17 W m-2) and spatial variations.

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

    PubMed Central

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

    2015-01-01

    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

  8. 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.

  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. Natural enemy-mediated indirect interactions among prey species: potential for enhancing biocontrol services in agroecosystems.

    PubMed

    Chailleux, Anaïs; Mohl, Emily K; Teixeira Alves, Mickaël; Messelink, Gerben J; Desneux, Nicolas

    2014-12-01

    Understanding how arthropod pests and their natural enemies interact in complex agroecosystems is essential for pest management programmes. Theory predicts that prey sharing a predator, such as a biological control agent, can indirectly reduce each other's density at equilibrium (apparent competition). From this premise, we (i) discuss the complexity of indirect interactions among pests in agroecosystems and highlight the importance of natural enemy-mediated indirect interactions other than apparent competition, (ii) outline factors that affect the nature of enemy-mediated indirect interactions in the field and (iii) identify the way to manipulate enemy-mediated interactions for biological control. We argue that there is a need to increase the link between community ecology theory and biological control to develop better agroecological methods of crop protection via conservation biological control. In conclusion, we identify (i) interventions to be chosen depending on agroecosystem characteristics and (ii) several lines of research that will improve the potential for enemy-mediated indirect interactions to be applied to biological control.

  12. Placental abruption and perinatal mortality with preterm delivery as a mediator: disentangling direct and indirect effects.

    PubMed

    Ananth, Cande V; VanderWeele, Tyler J

    2011-07-01

    The authors use recent methodology in causal inference to disentangle the direct and indirect effects that operate through a mediator in an exposure-response association paradigm. They demonstrate how total effects can be partitioned into direct and indirect effects even when the exposure and mediator interact. The impact of bias due to unmeasured confounding on the exposure-response association is assessed through a series of sensitivity analyses. These methods are applied to a problem in perinatal epidemiology to examine the extent to which the effect of abruption on perinatal mortality is mediated through preterm delivery. Data on over 26 million US singleton births (1995-2002) were utilized. Risks of mortality among abruption and nonabruption births were 102.7 and 6.2 per 1,000 births, respectively. Risk ratios of the natural direct and indirect (preterm delivery-mediated) effects of abruption on mortality were 10.18 (95% confidence interval: 9.80, 10.58) and 1.35 (95% confidence interval: 1.33, 1.38), respectively. The proportion of increased mortality risk mediated through preterm delivery was 28.1%, with even higher proportions associated with deliveries at earlier gestational ages. Sensitivity analyses underscore that the qualitative conclusions of some mediated effects and substantial direct effects are reasonably robust to unmeasured confounding of a fairly considerable magnitude.

  13. Mediation analysis to estimate direct and indirect milk losses due to clinical mastitis in dairy cattle.

    PubMed

    Detilleux, J; Kastelic, J P; Barkema, H W

    2015-03-01

    Milk losses associated with mastitis can be attributed to either effects of pathogens per se (i.e., direct losses) or effects of the immune response triggered by intramammary infection (indirect losses). The distinction is important in terms of mastitis prevention and treatment. Regardless, the number of pathogens is often unknown (particularly in field studies), making it difficult to estimate direct losses, whereas indirect losses can be approximated by measuring the association between increased somatic cell count (SCC) and milk production. An alternative is to perform a mediation analysis in which changes in milk yield are allocated into their direct and indirect components. We applied this method on data for clinical mastitis, milk and SCC test-day recordings, results of bacteriological cultures (Escherichia coli, Staphylococcus aureus, Streptococcus uberis, coagulase-negative staphylococci, Streptococcus dysgalactiae, and streptococci other than Strep. dysgalactiae and Strep. uberis), and cow characteristics. Following a diagnosis of clinical mastitis, the cow was treated and changes (increase or decrease) in milk production before and after a diagnosis were interpreted counterfactually. On a daily basis, indirect changes, mediated by SCC increase, were significantly different from zero for all bacterial species, with a milk yield decrease (ranging among species from 4 to 33g and mediated by an increase of 1000 SCC/mL/day) before and a daily milk increase (ranging among species from 2 to 12g and mediated by a decrease of 1000 SCC/mL/day) after detection. Direct changes, not mediated by SCC, were only different from zero for coagulase-negative staphylococci before diagnosis (72g per day). We concluded that mixed structural equation models were useful to estimate direct and indirect effects of the presence of clinical mastitis on milk yield.

  14. 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.

  15. 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

  16. 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

  17. The Role of Mediators in the Indirect Effects of Religiosity on Therapeutic Compliance in African Migrant HIV-Positive Patients.

    PubMed

    Mambet Doue, Constance; Roussiau, Nicolas

    2016-12-01

    This research investigates the indirect effects of religiosity (practice and belief) on therapeutic compliance in 81 HIV-positive patients who are migrants from sub-Saharan Africa (23 men and 58 women). Using analyses of mediation and standard multiple regression, including a resampling procedure by bootstrapping, the role of these mediators (magical-religious beliefs and nonuse of toxic substances) was tested. The results show that, through magical-religious beliefs, religiosity has a negative indirect effect, while with the nonuse of toxic substances, religious practice has a positive indirect effect. Beyond religiosity, the role of mediators is highlighted in the interaction with therapeutic compliance. PMID:26531838

  18. 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.

  19. 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.

  20. 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...

  1. 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...

  2. 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...

  3. 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…

  4. 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

  5. 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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

  11. Direct and Indirect Effects of Cytomegalovirus-Induced γδ T Cells after Kidney Transplantation

    PubMed Central

    Couzi, Lionel; Pitard, Vincent; Moreau, Jean-François; Merville, Pierre; Déchanet-Merville, Julie

    2015-01-01

    Despite effective anti-viral therapies, cytomegalovirus (CMV) is still associated with direct (CMV disease) and indirect effects (rejection and poor graft survival) in kidney transplant recipients. Recently, an unconventional T cell population (collectively designated as Vδ2neg γδ T cells) has been characterized during the anti-CMV immune response in all solid-organ and bone-marrow transplant recipients, neonates, and healthy people. These CMV-induced Vδ2neg γδ T cells undergo a dramatic and stable expansion after CMV infection, in a conventional “adaptive” manner. Similarly, as CMV-specific CD8+ αβ T cells, they exhibit an effector/memory TEMRA phenotype and cytotoxic effector functions. Activation of Vδ2neg γδ T cells by CMV-infected cells involves the γδ T cell receptor (TCR) and still ill-defined co-stimulatory molecules such as LFA-1. A multiple of Vδ2neg γδ TCR ligands are apparently recognized on CMV-infected cells, the first one identified being the major histocompatibility complex-related molecule endothelial protein C receptor. A singularity of CMV-induced Vδ2neg γδ T cells is to acquire CD16 expression and to exert an antibody-dependent cell-mediated inhibition on CMV replication, which is controlled by a specific cytokine microenvironment. Beyond the well-demonstrated direct anti-CMV effect of Vδ2neg γδ T cells, unexpected indirect effects of these cells have been also observed in the context of kidney transplantation. CMV-induced Vδ2neg γδ T cells have been involved in surveillance of malignancy subsequent to long-term immunosuppression. Moreover, CMV-induced CD16+ γδ T cells are cell effectors of antibody-mediated rejection of kidney transplants, and represent a new physiopathological contribution to the well-known association between CMV infection and poor graft survival. All these basic and clinical studies paved the road to the development of a future γδ T cell-based immunotherapy. In the meantime, γδ T cell

  12. 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.

  13. Mutualistic cleaner fish initiate trait-mediated indirect interactions by influencing the behaviour of coral predators.

    PubMed

    Adam, Thomas C

    2012-05-01

    1. Indirect interactions resulting from changes in organismal traits such as behaviour [i.e. trait-mediated indirect interactions (TMIIs)] are widespread in biological communities, yet few studies have explored the potential for mutualisms to initiate TMIIs. 2. This study used a combination of behavioural observations and manipulative field experiments to investigate potential TMIIs resulting from a mutualism between specialized cleaner fish and the 'clients' that visit cleaners for the removal of ectoparasites. 3. Behavioural observations indicate that the bluestreak cleaner wrasse, Labroides dimidiatus, increases local predation pressure on corals at cleaner stations by attracting corallivorous butterflyfish to their territories. 4. Observations of the ornate butterflyfish, Chaetodon ornatissimus, suggest a trade-off between seeking cleaning and foraging; individuals decreased their foraging rate at cleaner stations and shifted their diet to include a greater proportion of less preferred prey items. Nonetheless, predation pressure on corals was higher at cleaner stations because the spatial response of butterflyfish to cleaners more than compensated for their lower foraging rates. 5. The results of a field experiment suggest that the greater predation pressure observed at cleaner stations may be sufficient to reduce the growth rate of the unpreferred coral Porites rus. 6. Together, these results emphasize the need to consider mutualists as potential initiators of TMIIs and highlight the importance of integrating individual movement into conceptual analyses of TMIIs.

  14. 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

  15. Indirect localization of a magnetic domain wall mediated by quasi walls

    PubMed Central

    Lacour, D.; Montaigne, F.; Rougemaille, N.; Belkhou, R.; Raabe, J.; Hehn, M.

    2015-01-01

    The manipulation of magnetic domain walls in thin films and nanostructures opens new opportunities for fundamental and applied research. But controlling reliably the position of a moving domain wall still remains challenging. So far, most of the studies aimed at understanding the physics of pinning and depinning processes in the magnetic layer in which the wall moves (active layer). In these studies, the role of other magnetic layers in the stack has been often ignored. Here, we report an indirect localization process of 180° domain walls that occurs in magnetic tunnel junctions, commonly used in spintronics. Combining Scanning Transmission X-Ray Microscopy and micromagnetic simulations, magnetic configurations in both layers are resolved. When nucleating a 180° domain wall in the active layer, a quasi wall is created in the reference layer, atop the wall. The wall and its quasi wall must then be moved or positioned together, as a unique object. As a mutual effect, a localized change of the magnetic properties in the reference layer induces a localized quasi wall in the active layer. The two types of quasi walls are shown to be responsible for an indirect localization process of the 180° domain wall in the active layer. PMID:26011004

  16. 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.…

  17. 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

  18. 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

  19. 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).

  20. Indirect food web interactions mediated by predator-rodent dynamics: relative roles of lemmings and voles.

    PubMed

    Ims, Rolf A; Henden, John-André; Thingnes, Anders V; Killengreen, Siw T

    2013-01-01

    Production cycles in birds are proposed as prime cases of indirect interactions in food webs. They are thought to be driven by predators switching from rodents to bird nests in the crash phase of rodent population cycles. Although rodent cycles are geographically widespread and found in different rodent taxa, bird production cycles appear to be most profound in the high Arctic where lemmings dominate. We hypothesized that this may be due to arctic lemmings inducing stronger predator responses than boreal voles. We tested this hypothesis by estimating predation rates in dummy bird nests during a rodent cycle in low-Arctic tundra. Here, the rodent community consists of a spatially variable mix of one lemming (Lemmus lemmus) and two vole species (Myodes rufocanus and Microtus oeconomus) with similar abundances. In consistence with our hypothesis, lemming peak abundances predicted well crash-phase nest predation rates, whereas the vole abundances had no predictive ability. Corvids were found to be the most important nest predators. Lemmings appear to be accessible to the whole predator community which makes them particularly powerful drivers of food web dynamics.

  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. 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

  3. Testing the indirect effect of trait mindfulness on adolescent cigarette smoking through negative affect and perceived stress mediators.

    PubMed

    Black, David S; Milam, Joel; Sussman, Steve; Johnson, C Anderson

    2012-01-01

    Mindfulness refers to an enhanced attention to and awareness of present moment experience. This study examined how trait mindfulness, as measured with six items from Mindfulness Attention Awareness Scale, might influence adolescent cigarette smoking frequency through its impact on depressive affect, anger affect and perceived stress mediators. Self-reported data from Chinese adolescents (N = 5287, mean age = 16.2 years, SD = 0.7; 48.8% females) were collected within 24 schools. The product of coefficients test was used to determine significant mediation paths. Results from baseline cross-sectional data indicated that trait mindfulness had a significant indirect effect on past 30-day smoking frequency through depressive affect, anger affect and perceived stress mediators. Results from 13-month longitudinal data indicated that these indirect effects remained significant for depressive affect and perceived stress but not for anger affect. Findings from this study may suggest that heightening mindfulness among adolescents may indirectly reduce cigarette smoking perhaps by improving affect regulation competencies.

  4. 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.

  5. 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

  6. 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

  7. Indirect and direct associations between personality and psychological distress mediated by dispositional coping.

    PubMed

    Panayiotou, Georgia; Kokkinos, Constantinos M; Kapsou, Margarita

    2014-01-01

    The present study examines the association between coping and personality, by testing the hypothesis that dispositional coping mediates the relationship between personality and psychological distress. Canonical correlations evaluated the degree of the association among personality and coping dimensions in a community sample (N = 489) from Cyprus. Results partially support the hypothesized mediation model with Agreeableness predicting distress through the full mediation of avoidant coping, expression of negative feelings and active-positive coping. Partial mediation was found for Neuroticism and Openness. Canonical correlations deciphered how coping relates to the Big Five dimensions. Neuroticism was mostly associated with maladaptive coping, whereas Conscientiousness and Extraversion with adaptive coping.

  8. 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…

  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. Benzene on Cu(111): II. Molecular assembly due to Lateral van der Waals and Surface-State-Mediated Indirect Interactions

    NASA Astrophysics Data System (ADS)

    Hyldgaard, Per; Berland, Kristian; Einstein, T. L.

    2010-03-01

    Experiments show that benzene condenses into two different structural phases: a compact and a sparse phase, both of approximately hexagonal symmetry. The vdW-DF calculations demonstrate that the denser benzene-overlayer phase, with lattice constant 6.74 ,s due to direct benzene-benzene vdW attraction. The structure of the second, sparser phase, with lattice spacing 10.24 ,s attributed to the indirect electronic interactions mediated by the well-known metallic surface state on Cu(111). To support this claim, we use a formal Harris-functional approach to evaluate nonperturbatively the asymptotic form of this indirect interaction. Our extended vdW-DF scheme---which combines calculations of molecular physisorption, of direct intermolecular vdW coupling, and of indirect electronic interactions between the molecular adsorbates---accounts well for the structural phases of benzene on Cu(111). Our preliminary vdW-DF study of acene and quinone interactions provides building blocks for modeling of anthraquinone assembly on Cu(111).footnotetextG. Pawin, , L. Bartels, Science 313 (2006) 961

  11. 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...

  12. 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

  13. Assessing the mechanism of DNA damage induced by lead through direct and indirect interactions.

    PubMed

    Zhang, Hao; Wei, Kai; Zhang, Mengyu; Liu, Rutao; Chen, Yadong

    2014-07-01

    Lead still possesses great threats to human health owing to its widespread distribution in the environment caused by human activities, although various actions have been taken to cut down the use and distribution of lead. In this work, mechanisms of DNA damage caused by lead through indirect and direct interactions were investigated. Results from comet assay showed lead at 1-10 μM induced DNA strand breaks in mice liver cells according to olive tail moment analysis. Signals of DNA-protein crosslinks (DPC) were not significantly detected until exposed at 100 μM Pb(2+). Further more, direct interactions between Pb(2+) and DNA were explored to determine the binding mode between them using spectra analysis, isothermal titration calorimetry studies and molecular docking investigations, which indicated that Pb(2+) could bind to DNA with four binding sites to form Pb(2)(+)-DNA complex by minor groove binding effects and electrostatic forces, resulting in damage to the structure of DNA double helix. Combined studies of lead genotoxicity in indirect (comet assay and DPC assay) and direct (binding mode investigations) interactions can be applied to study the potential damages to DNA induced by heavy metal pollutants.

  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.

  15. 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

  16. The thymoprotective function of leptin is indirectly mediated via suppression of obesity.

    PubMed

    Sreenivasan, Jayasree; Schlenner, Susan; Franckaert, Dean; Dooley, James; Liston, Adrian

    2015-09-01

    Leptin is an adipokine that regulates metabolism and plays an important role as a neuroendocrine hormone. Leptin mediates these functions via the leptin receptor, and deficiency in either leptin or its receptor leads to obesity in humans and mice. Leptin has far reaching effects on the immune system, as observed in obese mice, which display decreased thymic function and increased inflammatory responses. With expression of the leptin receptor on T cells and supporting thymic epithelium, aberrant signalling through the leptin receptor has been thought to be the direct cause of thymic involution in obese mice. Here, we demonstrate that the absence of leptin receptor on either thymic epithelial cells or T cells does not lead to the loss of thymic function, demonstrating that the thymoprotective effect of leptin is mediated by obesity suppression rather than direct signalling to the cellular components of the thymus.

  17. Evolutionary change from induced to constitutive expression of an indirect plant resistance.

    PubMed

    Heil, Martin; Greiner, Sabine; Meimberg, Harald; Krüger, Ralf; Noyer, Jean-Louis; Heubl, Günther; Linsenmair, K Eduard; Boland, Wilhelm

    2004-07-01

    Induced plant resistance traits are expressed in response to attack and occur throughout the plant kingdom. Despite their general occurrence, the evolution of such resistances has rarely been investigated. Here we report that extrafloral nectar, a usually inducible trait, is constitutively secreted by Central American Acacia species that are obligately inhabited by ants. Extrafloral nectar is secreted as an indirect resistance, attracting ants that defend plants against herbivores. Leaf damage induces extrafloral nectar secretion in several plant species; among these are various Acacia species and other Fabaceae investigated here. In contrast, Acacia species obligately inhabited by symbiotic ants nourish these ants by secreting extrafloral nectar constitutively at high rates that are not affected by leaf damage. The phylogeny of the genus Acacia and closely related genera indicate that the inducibility of extrafloral nectar is the plesiomorphic or 'original' state, whereas the constitutive extrafloral nectar flow is derived within Acacia. A constitutive resistance trait has evolved from an inducible one, obviously in response to particular functional demands.

  18. A Novel Small Molecule Inhibitor of Influenza A Viruses that Targets Polymerase Function and Indirectly Induces Interferon

    PubMed Central

    Ortigoza, Mila Brum; Dibben, Oliver; Maamary, Jad; Martinez-Gil, Luis; Leyva-Grado, Victor H.; Abreu, Pablo; Ayllon, Juan; Palese, Peter; Shaw, Megan L.

    2012-01-01

    Influenza viruses continue to pose a major public health threat worldwide and options for antiviral therapy are limited by the emergence of drug-resistant virus strains. The antiviral cytokine, interferon (IFN) is an essential mediator of the innate immune response and influenza viruses, like many viruses, have evolved strategies to evade this response, resulting in increased replication and enhanced pathogenicity. A cell-based assay that monitors IFN production was developed and applied in a high-throughput compound screen to identify molecules that restore the IFN response to influenza virus infected cells. We report the identification of compound ASN2, which induces IFN only in the presence of influenza virus infection. ASN2 preferentially inhibits the growth of influenza A viruses, including the 1918 H1N1, 1968 H3N2 and 2009 H1N1 pandemic strains and avian H5N1 virus. In vivo, ASN2 partially protects mice challenged with a lethal dose of influenza A virus. Surprisingly, we found that the antiviral activity of ASN2 is not dependent on IFN production and signaling. Rather, its IFN-inducing property appears to be an indirect effect resulting from ASN2-mediated inhibition of viral polymerase function, and subsequent loss of the expression of the viral IFN antagonist, NS1. Moreover, we identified a single amino acid mutation at position 499 of the influenza virus PB1 protein that confers resistance to ASN2, suggesting that PB1 is the direct target. This two-pronged antiviral mechanism, consisting of direct inhibition of virus replication and simultaneous activation of the host innate immune response, is a unique property not previously described for any single antiviral molecule. PMID:22577360

  19. Redox-Mediated Indirect Fluorescence Immunoassay for the Detection of Disease Biomarkers Using Dopamine-Functionalized Quantum Dots.

    PubMed

    Zhang, Wen-Hui; Ma, Wei; Long, Yi-Tao

    2016-05-17

    Here, we report a redox-mediated indirect fluorescence immunoassay (RMFIA) for the detection of the disease biomarker α-fetoprotein (AFP) using dopamine (DA)-functionalized CdSe/ZnS quantum dots (QDs). In this immunoassay, tyrosinase was conjugated with the detection antibody and acted as a bridge connecting the fluorescence signals of the QDs with the concentration of the disease biomarkers. The tyrosinase label used for RMFIA catalyzed the enzymatic oxidation of DAs on the surface of functionalized QDs and caused fluorescence quenching in the presence of the analyte. Using this technique, we obtained a limit of detection as low as 10 pM for AFP. This assay's potential for clinical analysis was demonstrated by detecting the real sera of patients with hepatocellular carcinoma (HCC). This study makes the first use of RMFIA for the rapid detection of AFP, opening up a new pathway for the detection of disease biomarkers.

  20. Indirect airway challenges.

    PubMed

    Joos, G F; O'Connor, B; Anderson, S D; Chung, F; Cockcroft, D W; Dahlén, B; DiMaria, G; Foresi, A; Hargreave, F E; Holgate, S T; Inman, M; Lötvall, J; Magnussen, H; Polosa, R; Postma, D S; Riedler, J

    2003-06-01

    Indirect challenges act by causing the release of endogenous mediators that cause the airway smooth muscle to contract. This is in contrast to the direct challenges where agonists such as methacholine or histamine cause airflow limitation predominantly via a direct effect on airway smooth muscle. Direct airway challenges have been used widely and are well standardised. They are highly sensitive, but not specific to asthma and can be used to exclude current asthma in a clinic population. Indirect bronchial stimuli, in particular exercise, hyperventilation, hypertonic aerosols, as well as adenosine, may reflect more directly the ongoing airway inflammation and are therefore more specific to identify active asthma. They are increasingly used to evaluate the prevalence of bronchial hyperresponsiveness and to assess specific problems in patients with known asthma, e.g. exercise-induced bronchoconstriction, evaluation before scuba diving. Direct bronchial responsiveness is only slowly and to a modest extent, influenced by repeated administration of inhaled steroids. Indirect challenges may reflect more closely acute changes in airway inflammation and a change in responsiveness to an indirect stimulus may be a clinically relevant marker to assess the clinical course of asthma. Moreover, some of the indirect challenges, e.g. hypertonic saline and mannitol, can be combined with the assessment of inflammatory cells by induction of sputum.

  1. [Health risk induced by estrogens during unplanned indirect potable reuse of reclaimed water from domestic wastewater].

    PubMed

    Wu, Qian-Yuan; Shao, Yi-Ru; Wang, Chao; Sun, Yan; Hu, Hong-Ying

    2014-03-01

    The estrogenic endocrine disruptors in reclaimed water from domestic wastewater may induce health risks to human being, when reclaimed water is used for augmentation of drinking water unplannedly and indirectly. This study investigated changes in concentrations of estrone, estradiol, 17alpha-ethinyl estradiol, bisphenol A, nonylphenol and octylphenol in reclaimed water during the reuse of reclaimed water for augmentation to water source such as lakes and reservoir via river. Thereafter, health risk induced by estrogens during the resue of reclaimed water was evaluated. The concentration of estrogen in secondary effluent ranged 0.1-100 ng x L(-1). The highest concentrations of bisphenol A and nonylphenol reached up to 1-10 microg x L(-1). During the indirect reuse of reclaimed water as potable water, the dilution and degradation in river and lake, and the removal by drinking water treatment process could change the concentrations of estrogen. The non-carcinogenic risks of estrone, estradiol, bisphenol A, nonylphenol and octylphenol were lower than 1. When the hydraulic retention time of 17alpha-ethinyl estradiol (EE2) in lakes and reservoir was higher than 30 days, the non-carcinogenic risk of EE2 was lower than 1 in most cases. When the hydraulic retention time of EE2 in lakes and reservoir was less than 30 days and the percentages of reclaimed water in drinking water were higher than 50%, the non-carcinogenic risk induced by EE2 was higher than 1 in 20%-50% samples. This indicated that the risks of EE2 should be concerned.

  2. 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

  3. Stratospheric Ozone-induced Indirect Radiative Effects on Antarctic Sea Ice

    NASA Astrophysics Data System (ADS)

    Hu, Y.; Xia, Y.; LIU, J.; Huang, Y.

    2015-12-01

    Recent studies demonstrated that the Antarctic Ozone Hole has important influences on Antarctic sea ice. While all these have focused on stratospheric ozone-induced dynamic effects on sea ice, here we show results that ozone-induced indirect radiative effects have important influences on Antarctic sea ice. Our simulations demonstrate that the recovery of the Antarctic Ozone Hole causes equatorward shift of clouds over the Southern Ocean. The cloud-band shift leads to reduction of downward infrared radiation, which causes surface cooling. On the other hand, it also causes increasing solar radiation on the surface. However, the increase in solar radiation is offset by surface reflection due to increasing sea ice. As a result solar radiation absorbed by the surface is reduced, which also causes surface cooling. Therefore, the overall ozone-induced cloud radiative effect is to cool the surface and causes expansion of sea ice around the Antarctic. As shown in previous studies, the cloud-band shift is associated with the equatorward shift of the westerly jet stream around the Antarctic. Our simulations also demonstrate increasing snow rate near the sea ice edge, which also contributes to Antarctic sea-ice expansion. The ozone-induced cloud radiative effect would mitigate Antarctic sea-ice melting due to greenhouse warming in the 21st century.

  4. Transient isotachophoretic-electrophoretic separations of lanthanides with indirect laser-induced fluorescence detection.

    PubMed

    Church, M N; Spear, J D; Russo, R E; Klunder, G L; Grant, P M; Andresen, B D

    1998-07-01

    Indirect laser-induced fluorescence was used for the detection of several lanthanide species separated by capillary electrophoresis. Quinine sulfate was the fluorescent component of the background electrolyte, and α-hydroxyisobutyric acid was added as a complexing agent to enable the separation of analyte ions that have similar mobilities. The UV lines (333-364 nm) of an argon ion laser were used as the excitation source with a diode array detector for monitoring the fluorescent emission at 442 nm. Electrokinetic injections and transient isotachophoresis were implemented to stack the analyte ions into more concentrated zones. On-line preconcentration factors were determined to be ∼700 and resulted in limits of detection for La(3+), Ce(3+), Pr(3+), Nd(3+), Sm(3+), and Eu(3+) in the low-ppb range (6-11 nM).

  5. 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

  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. 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

  8. 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

  9. 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.

  10. Probabilistic evaluation of main coolant pipe break indirectly induced by earthquakes: Savannah River Project L and P Reactors

    SciTech Connect

    Short, S.A.; Wesley, D.A.; Awadalla, N.G.; Kennedy, R.P.; Westinghouse Savannah River Co., Aiken, SC; Structural Mechanics Consulting, Inc., Yorba Linda, CA )

    1989-01-01

    A probabilistic evaluation of seismically-induced indirect pipe break for the Savannah River Project (SRP) L- and P-Reactor main coolant (process water) piping has been conducted. Seismically-induced indirect pipe break can result primarily from: (1) failure of the anchorage of one or more of the components to which the pipe is anchored; or (2) failure of the pipe due to collapse of the structure. The potential for both types of seismically-induced indirect failures was identified during a seismic walkdown of the main coolant piping. This work involved: (1) identifying components or structures whose failure could result in pipe failure; (2) developing seismic capacities or fragilities of these components; (3) combining component fragilities to develop plant damage state fragilities; and (4) convolving the plant seismic fragilities with a probabilistic seismic hazard estimate for the site in order to obtain estimates of seismic risk in terms of annual probability of seismic-induced indirect pipe break. 6 refs., 5 figs., 2 tabs.

  11. Evidence for indirect effects of pain catastrophizing on clinical pain among myofascial temporomandibular disorder participants: the mediating role of sleep disturbance.

    PubMed

    Buenaver, Luis F; Quartana, Phillip J; Grace, Edward G; Sarlani, Eleni; Simango, Mpepera; Edwards, Robert R; Haythornthwaite, Jennifer A; Smith, Michael T

    2012-06-01

    Sleep disturbance and pain catastrophizing are important mediators of the chronic pain experience. To date, these factors have not been considered concurrently despite compelling theoretical rationale to do so. In the present study, we examined whether pain catastrophizing not only has direct effects on clinical pain and pain-related interference, but also indirect effects through its association with sleep disturbance. We evaluated this hypothesis using a cohort (n=214) of myofascial temporomandibular disorder participants using a statistical bootstrapping technique recommended for tests of indirect effects. Results suggested that pain catastrophizing was associated with greater sleep disturbance, and that a significant portion of variance in clinical pain severity and pain-related interference attributable to pain catastrophizing was mediated by sleep disturbance. Supplementary analyses revealed that the rumination component of catastrophizing seemed to be indirectly related to clinical outcomes through sleep disturbance. No evidence for indirect effects was observed for helplessness and magnification components. These results suggest that rumination about pain may contribute to clinical pain indirectly through alterations in sleep. Prospective studies are needed to examine lagged associations between these constructs. These findings have important theoretical and clinical implications. Critically, interventions that reduce pain catastrophizing may concurrently improve sleep and clinical pain. PMID:22417656

  12. Indirect laser-induced fluorescence detection for capillary electrophoresis using a frequency-doubled diode laser.

    PubMed

    Ragozina, Natalia; Pütz, Michael; Faubel, Werner; Pyell, Ute

    2003-01-01

    A blue (452 nm) frequency-doubled diode laser with a quasi-cw optical output power of 10 microW is used for indirect laser-induced fluorescence detection in combination with the capillary electrophoretic separation of inorganic anions. As fluorescing probe ion the anion of 8-hydroxypyrene-1,3,6-trisulfonic acid (HPTS) was selected having an absorption maximum of 454 nm in alkaline medium. Employing a capillary coated with linear acrylamide, baseline separation of eight inorganic anions was possible within 5 min. With a separation buffer containing 50 micromol.L(-1) HPTS and 10 mmol.L(-1) lysine the limits of detection for sulfate, nitrite, nitrate, azide, thiocyanate, and chlorate were between 0.9 and 4.7 micromol.L(-1). Separation of chloride and sulfate was achieved by adding 0.25 mmol.L(-1) calcium hydroxide to the separation buffer. Inorganic anions in several mineral and tap water samples have been determined with the technique developed and results are compared to data obtained by ion chromatography in combination with conductivity detection after conductivity suppression.

  13. The electronic origin of shear-induced direct to indirect gap transition and anisotropy diminution in phosphorene.

    PubMed

    Sa, Baisheng; Li, Yan-Ling; Sun, Zhimei; Qi, Jingshan; Wen, Cuilian; Wu, Bo

    2015-05-29

    Artificial monolayer black phosphorus, so-called phosphorene, has attracted global interest with its distinguished anisotropic, optoelectronic, and electronic properties. Here, we unraveled the shear-induced direct-to-indirect gap transition and anisotropy diminution in phosphorene based on first-principles calculations. Lattice dynamic analysis demonstrates that phosphorene can sustain up to 10% applied shear strain. The bandgap of phosphorene experiences a direct-to- indirect transition when 5% shear strain is applied. The electronic origin of the direct-to-indirect gap transition from 1.54 eV at ambient conditions to 1.22 eV at 10% shear strain for phosphorene is explored. In addition, the anisotropy diminution in phosphorene is discussed by calculating the maximum sound velocities, effective mass, and decomposed charge density, which signals the undesired shear-induced direct-to-indirect gap transition in applications of phosphorene for electronics and optoelectronics. On the other hand, the shear-induced electronic anisotropy properties suggest that phosphorene can be applied as the switcher in nanoelectronic applications.

  14. 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.

  15. Tobacco overexpressing β-ocimene induces direct and indirect responses against aphids in receiver tomato plants.

    PubMed

    Cascone, Pasquale; Iodice, Luigi; Maffei, Massimo E; Bossi, Simone; Arimura, Gen-Ichiro; Guerrieri, Emilio

    2015-01-15

    In the last decade plant-to-plant communication has received an increasing attention, particularly for the role of Volatile Organic Compounds as possible elicitors of plant defense. The role of β-ocimene as an interspecific elicitor of plant defense has been recently assessed in multitrophic systems including different plant species (Solanaceae, Poaceae, legumes) and different pest species including chewer insects and phytophagous mites. Both chewer insects and phytophagous mites are known to elicit specific plant defensive pathways which are different (at least in part) from those elicited by sap feeders. The aim of this research was to fill this gap of knowledge and to assess the role of β-ocimene as an elicitor of plant defense against aphid pests, which are sap feeders. For this purpose we used as transgenic tobacco plant releasing an odour plume enriched in this compound as emitter and a tomato plant as receiver. We selected the aphid Macrosiphum euphorbiae and its natural enemy, the parasitoid Aphidius ervi, as the targets of plant induced defense. Tomato plant defense induced by β-ocimene was assessed by characterizing the aphid performance in terms of fixing behaviour, development and reproduction (direct plant defense) and the parasitoid performance in terms of attraction towards tomato plants (indirect plant defense). The characterization of tomato response to β-ocimene was completed by the identification of Volatile Organic Compounds as released by conditioned tomato plants. Tomato plants that were exposed to the volatiles of transgenic tobacco enriched in β-ocimene resulted in less suitable for the aphids in respect to control ones (direct defense). On tomato plants "elicited" by β-ocimene we recorded: a significant lower number of aphids settled; a significant lower number newborn nymphs; a significant lower weight of aphids feeding. In addition, tomato plants "elicited" by β-ocimene resulted became more attractive towards the parasitoid A. ervi

  16. Can we improve structured sequence processing? Exploring the direct and indirect effects of computerized training using a mediational model.

    PubMed

    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

  17. 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.

  18. 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…

  19. 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.

  20. 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

  1. 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

  2. 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%).

  3. Opioid-induced immunosuppression: is it centrally mediated or peripherally mediated?

    PubMed

    Wei, Gang; Moss, Jonathan; Yuan, Chun Su

    2003-06-01

    Opioid compounds are commonly used pain medications. However, their administration is associated with a number of side-effects. Among them, opioid-induced immunosuppression is a significant medical problem, which is evidenced by a strong association between the use of opioids and exacerbated infections, including AIDS. Research data have demonstrated the effects of opioids to be suppressive on phagocytic, natural killer (NK), B and T cells. However, these immunosuppressive effects may be mediated by mechanisms different from those for antinociceptive actions. This article reviews possible central and peripheral mechanisms of opioid-induced immunosuppression. To the extent that peripherally mediated immunosuppressive effects play a significant role in opioid-induced immunosuppression, novel peripheral opioid antagonists may have a therapeutic role in attenuating opioid-induced immunosuppression without affecting analgesia.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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).

  10. T-cell mediated immunity and the role of TRAIL in sepsis-induced immunosuppression

    PubMed Central

    Condotta, Stephanie A.; Cabrera-Perez, Javier; Badovinac, Vladimir P.; Griffith, Thomas S.

    2013-01-01

    Sepsis is the leading cause of death in most intensive care units, and the death of septic patients usually does not result from the initial septic event but rather from subsequent nosocomial infections. Patients who survive severe sepsis often display severely compromised immune function. Not only is there significant apoptosis of lymphoid and myeloid cells that depletes critical components of the immune system during sepsis, there is also decreased function of the remaining immune cells. Studies in animals and humans suggest the immune defects that occur during sepsis may be critical to the pathogenesis and subsequent mortality. This review is focused on sepsis-induced alterations with the CD8 T-cell compartment that can affect the control of secondary heterologous infections. Understanding how a septic event directly influences CD8 T-cell populations through apoptotic death and homeostatic proliferation and indirectly by immune-mediated suppression will provide valuable starting points for developing new treatment options. PMID:23510024

  11. 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

  12. Biomolecular damage induced by ionizing radiation: the direct and indirect effects of low-energy electrons on DNA.

    PubMed

    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.

  13. 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.

  14. Caspase-9 mediates Puma activation in UCN-01-induced apoptosis.

    PubMed

    Nie, C; Luo, Y; Zhao, X; Luo, N; Tong, A; Liu, X; Yuan, Z; Wang, C; Wei, Y

    2014-10-30

    The protein kinase inhibitor 7-hydroxystaurosporine (UCN-01) is one of the most potent and frequently used proapoptotic stimuli. The BH3-only molecule of Bcl-2 family proteins has been reported to contribute to UCN-01-induced apoptosis. Here we have found that UCN-01 triggers Puma-induced mitochondrial apoptosis pathway. Our data confirmed that Akt-FoxO3a pathway mediated Puma activation. Importantly, we elucidate the detailed mechanisms of Puma-induced apoptosis. Our data have also demonstrated that caspase-9 is a decisive molecule of Puma induction after UCN-01 treatment. Caspase-9 mediates apoptosis through two kinds of feedback loops. On the one hand, caspase-9 enhances Puma activation by cleaving Bcl-2 and Bcl-xL independent of caspase-3. On the other hand, caspase-9 directly activated caspase-3 in the presence of caspase-3. Caspase-3 could cleave XIAP in an another positive feedback loop to further sensitize cancer cells to UCN-01-induced apoptosis. Therefore, caspase-9 mediates Puma activation to determine the threshold for overcoming chemoresistance in cancer cells.

  15. The chloroplast-localized phospholipases D α4 and α5 regulate herbivore-induced direct and indirect defenses in rice.

    PubMed

    Qi, Jinfeng; Zhou, Guoxin; Yang, Lijuan; Erb, Matthias; Lu, Yanhua; Sun, Xiaoling; Cheng, Jiaan; Lou, Yonggen

    2011-12-01

    The oxylipin pathway is of central importance for plant defensive responses. Yet, the first step of the pathway, the liberation of linolenic acid following induction, is poorly understood. Phospholipases D (PLDs) have been hypothesized to mediate this process, but data from Arabidopsis (Arabidopsis thaliana) regarding the role of PLDs in plant resistance have remained controversial. Here, we cloned two chloroplast-localized PLD genes from rice (Oryza sativa), OsPLDα4 and OsPLDα5, both of which were up-regulated in response to feeding by the rice striped stem borer (SSB) Chilo suppressalis, mechanical wounding, and treatment with jasmonic acid (JA). Antisense expression of OsPLDα4 and -α5 (as-pld), which resulted in a 50% reduction of the expression of the two genes, reduced elicited levels of linolenic acid, JA, green leaf volatiles, and ethylene and attenuated the SSB-induced expression of a mitogen-activated protein kinase (OsMPK3), a lipoxygenase (OsHI-LOX), a hydroperoxide lyase (OsHPL3), as well as a 1-aminocyclopropane-1-carboxylic acid synthase (OsACS2). The impaired oxylipin and ethylene signaling in as-pld plants decreased the levels of herbivore-induced trypsin protease inhibitors and volatiles, improved the performance of SSB and the rice brown planthopper Nilaparvata lugens, and reduced the attractiveness of plants to a larval parasitoid of SSB, Apanteles chilonis. The production of trypsin protease inhibitors in as-pld plants could be partially restored by JA, while the resistance to rice brown planthopper and SSB was restored by green leaf volatile application. Our results show that phospholipases function as important components of herbivore-induced direct and indirect defenses in rice.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Nrf2 regulates curcumin-induced aldose reductase expression indirectly via nuclear factor-kappaB.

    PubMed

    Kang, Eun Sil; Kim, Gil Hyeong; Kim, Hyo Jung; Woo, Im Sun; Ham, Sun Ah; Jin, Hana; Kim, Min Young; Kim, Hye Jung; Lee, Jae Heun; Chang, Ki Churl; Seo, Han Geuk; Hwang, Jin-Yong

    2008-07-01

    The osmotic response element (ORE) differs from the nuclear factor-kappaB (NF-kappaB) binding sequence by a single base pair; therefore, we investigated the involvement of NF-kappaB in the induction of aldose reductase (AR) by curcumin. Curcumin, an herb-derived polyphenolic compound, elicited an increase in the expression and promoter activity of the AR gene in a nuclear factor-erythroid 2-related factor 2 (Nrf2)-dependent manner. Small interfering RNA (siRNA) against p65 or BAY11-7082, an inhibitor of NF-kappaB, significantly suppressed the curcumin and/or Nrf2-induced increase in expression levels and promoter activity of the AR gene. BAY11-7082 or siRNA against p65 also attenuated the curcumin-induced increase in the promoter activity of the wild type AR-ORE(wt) gene, but not that of the mutated AR-ORE(mt), indicating that the ORE is essential for the response to NF-kappaB. The expression of p65, the promoter activity and DNA binding activity of NF-kappaB were enhanced in the presence of curcumin in cells that were transfected with Nrf2 compared to those treated with curcumin alone. Cells that had been preincubated with curcumin demonstrated resistance to reactive oxygen species-induced cell damage through the suppressive effects in the generation of reactive aldehydes. These effects were significantly attenuated in the presence of BAY11-7082, indicating the involvement of NF-kappaB in the cellular response of AR to oxidative stress and toxic aldehydes.

  1. IP3-mediated octopamine-induced synaptic enhancement of crayfish LG neurons.

    PubMed

    Araki, Makoto; Nagayama, Toshiki

    2012-08-01

    The biogenic amines, octopamine and serotonin, modulate the synaptic activity of the lateral giant interneuron (LG) circuitry of the crayfish escape behavior. Bath application of both octopamine and serotonin enhances the synaptic responses of LG to sensory stimulation. We have shown previously (Araki et al. J Neurophysiol 94:2644-2652, 2005) that a serotonin-induced enhancement of the LG response was mediated by an increase in cAMP levels following activation of adenylate cyclase; however, octopamine acts independently. Here, we clarify how octopamine enhances the LG response during sensory stimulation using physiological and pharmacological analyses. When phospholipase C inhibitor U-73122 was directly injected into the LG before biogenic amine application, it abolished the enhancing effect of octopamine on direct sensory input to the LG, but did not block indirect input via sensory interneurons or the effect of serotonin. Direct injection of IP(3), and its analogue adenophostin A, into the LG increased the synaptic response of the LG to sensory stimulation. Thus, IP(3) mediates octopamine-induced synaptic enhancement of the LG, but serotonin acts independently. These results indicate that both octopamine and serotonin enhance the synaptic responses of the LG to sensory stimulation, but that they activate two different signaling cascades in the LG.

  2. 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.

  3. 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.

  4. 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

  5. Tom70 Mediates Sendai Virus-Induced Apoptosis on Mitochondria

    PubMed Central

    Wei, Bo; Cui, Ye; Huang, Yuefeng; Liu, Heng; Li, Lin; Li, Mi; Ruan, Kang-Cheng

    2015-01-01

    ABSTRACT Virus infection triggers immediate innate immune responses. Apoptosis represents another effective means to restrict virus invasion, besides robust expression of host cytokines and chemokines. IRF3 was recently demonstrated to be indispensable for Sendai virus (SeV)-induced apoptosis, but the underlying mechanism is not fully understood. Here we report that a dynamic protein complex, Tom70/Hsp90/IRF3/Bax, mediates SeV-induced apoptosis. The cytosolic proapoptotic protein Bax interacts specifically with IRF3 upon virus infection. The mitochondrial outer membrane protein Tom70 recruits IRF3 to mitochondria via Hsp90. Consequently, the relocation of Bax onto mitochondria induces the leakage of cytochrome c into the cytosol and initiates the corresponding apoptosis. Interestingly, IKK-i is essential for this apoptosis, whereas TBK1 is dispensable. Collectively, our study characterizes a novel protein complex that is important for SeV-induced apoptosis. IMPORTANCE Apoptosis is an effective means of sacrificing virus-infected cells and restraining the spread of virus. In this study, we demonstrate that IRF3 associates with Bax upon virus infection. Tom70 recruits this protein complex to the mitochondrial outer membrane through Hsp90, which thus induces the release of cytochrome c into the cytosol, initiating virus-induced apoptosis. Interestingly, IKK-i plays an essential role in this activation. This study uncovers a novel mechanism of SeV-induced apoptosis. PMID:25609812

  6. Ectomycorrhizal fungi mediate indirect effects of a bark beetle outbreak on secondary chemistry and establishment of pine seedlings.

    PubMed

    Karst, Justine; Erbilgin, Nadir; Pec, Gregory J; Cigan, Paul W; Najar, Ahmed; Simard, Suzanne W; Cahill, James F

    2015-11-01

    Dendroctonus ponderosae has killed millions of Pinus contorta in western North America with subsequent effects on stand conditions, including changes in light intensity, needle deposition, and the composition of fungal community mutualists, namely ectomycorrhizal fungi. It is unknown whether these changes in stand conditions will have cascading consequences for the next generation of pine seedlings. To test for transgenerational cascades on pine seedlings, we tested the effects of fungal inoculum origin (beetle-killed or undisturbed stands), light intensity and litter (origin and presence) on seedling secondary chemistry and growth in a glasshouse. We also tracked survival of seedlings over two growing seasons in the same stands from which fungi and litter were collected. Fungal communities differed by inoculum origin. Seedlings grown with fungi collected from beetle-killed stands had lower monoterpene concentrations and fewer monoterpene compounds present compared with seedlings grown with fungi collected from undisturbed stands. Litter affected neither monoterpenes nor seedling growth. Seedling survival in the field was lower in beetle-killed than in undisturbed stands. We demonstrate that stand mortality caused by prior beetle attacks of mature pines have cascading effects on seedling secondary chemistry, growth and survival, probably mediated through effects on below-ground mutualisms. PMID:26033270

  7. Ectomycorrhizal fungi mediate indirect effects of a bark beetle outbreak on secondary chemistry and establishment of pine seedlings.

    PubMed

    Karst, Justine; Erbilgin, Nadir; Pec, Gregory J; Cigan, Paul W; Najar, Ahmed; Simard, Suzanne W; Cahill, James F

    2015-11-01

    Dendroctonus ponderosae has killed millions of Pinus contorta in western North America with subsequent effects on stand conditions, including changes in light intensity, needle deposition, and the composition of fungal community mutualists, namely ectomycorrhizal fungi. It is unknown whether these changes in stand conditions will have cascading consequences for the next generation of pine seedlings. To test for transgenerational cascades on pine seedlings, we tested the effects of fungal inoculum origin (beetle-killed or undisturbed stands), light intensity and litter (origin and presence) on seedling secondary chemistry and growth in a glasshouse. We also tracked survival of seedlings over two growing seasons in the same stands from which fungi and litter were collected. Fungal communities differed by inoculum origin. Seedlings grown with fungi collected from beetle-killed stands had lower monoterpene concentrations and fewer monoterpene compounds present compared with seedlings grown with fungi collected from undisturbed stands. Litter affected neither monoterpenes nor seedling growth. Seedling survival in the field was lower in beetle-killed than in undisturbed stands. We demonstrate that stand mortality caused by prior beetle attacks of mature pines have cascading effects on seedling secondary chemistry, growth and survival, probably mediated through effects on below-ground mutualisms.

  8. Arginase Activity Mediates Retinal Inflammation in Endotoxin-Induced Uveitis

    PubMed Central

    Zhang, Wenbo; Baban, Babak; Rojas, Modesto; Tofigh, Sohrab; Virmani, Suvika K.; Patel, Chintan; Behzadian, M. Ali; Romero, Maritza J.; Caldwell, Robert W.; Caldwell, Ruth B.

    2009-01-01

    Arginase has been reported to reduce nitric oxide bioavailability in cardiovascular disease. However, its specific role in retinopathy has not been studied. In this study, we assessed the role of arginase in a mouse model of endotoxin-induced uveitis induced by lipopolysaccharide (LPS) treatment. Measurement of arginase expression and activity in the retina revealed a significant increase in arginase activity that was associated with increases in both mRNA and protein levels of arginase (Arg)1 but not Arg2. Immunofluorescence and flow cytometry confirmed this increase in Arg1, which was localized to glia and microglia. Arg1 expression and activity were also increased in cultured Muller cells and microglia treated with LPS. To test whether arginase has a role in the development of retinal inflammation, experiments were performed in mice deficient in one copy of the Arg1 gene and both copies of the Arg2 gene or in mice treated with a selective arginase inhibitor. These studies showed that LPS-induced increases in inflammatory protein production, leukostasis, retinal damage, signs of anterior uveitis, and uncoupling of nitric oxide synthase were blocked by either knockdown or inhibition of arginase. Furthermore, the LPS-induced increase in Arg1 expression was abrogated by blocking NADPH oxidase. In conclusion, these studies suggest that LPS-induced retinal inflammation in endotoxin-induced uveitis is mediated by NADPH oxidase-dependent increases in arginase activity. PMID:19590038

  9. Auditory-Induced Emotion Mediates Perceptual Categorization of Everyday Sounds

    PubMed Central

    Bergman, Penny; Västfjäll, Daniel; Tajadura-Jiménez, Ana; Asutay, Erkin

    2016-01-01

    Research has shown that emotion categorization plays an important role in perception and categorization in the visual domain. In the present paper, we investigated the role of auditory-induced emotions for auditory perception. We further investigated whether the emotional responses mediate other perceptual judgments of sounds. In an experiment, participants either rated general dissimilarities between sounds or dissimilarities of specific aspects of sounds. The results showed that the general perceptual salience map could be explained by both the emotional responses to, and perceptual aspects of, the sounds. Importantly, the perceptual aspects were mediated by emotional responses. Together these results show that emotions are an integral part of auditory perception that is used as the intuitive basis for categorizing everyday sounds. PMID:27790172

  10. Crystal structure of pseudouridine synthase RluA: indirect sequence readout through protein-induced RNA structure.

    PubMed

    Hoang, Charmaine; Chen, Junjun; Vizthum, Caroline A; Kandel, Jason M; Hamilton, Christopher S; Mueller, Eugene G; Ferré-D'Amaré, Adrian R

    2006-11-17

    RluA is a dual-specificity enzyme responsible for pseudouridylating 23S rRNA and several tRNAs. The 2.05 A resolution structure of RluA bound to a substrate RNA comprising the anticodon stem loop of tRNA(Phe) reveals that enzyme binding induces a dramatic reorganization of the RNA. Instead of adopting its canonical U turn conformation, the anticodon loop folds into a new structure with a reverse-Hoogsteen base pair and three flipped-out nucleotides. Sequence conservation, the cocrystal structure, and the results of structure-guided mutagenesis suggest that RluA recognizes its substrates indirectly by probing RNA loops for their ability to adopt the reorganized fold. The planar, cationic side chain of an arginine intercalates between the reverse-Hoogsteen base pair and the bottom pair of the anticodon stem, flipping the nucleotide to be modified into the active site of RluA. Sequence and structural comparisons suggest that pseudouridine synthases of the RluA, RsuA, and TruA families employ an equivalent arginine for base flipping.

  11. 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.

  12. 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

  13. 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.

  14. The cytotoxicity of the anticancer drug elesclomol is due to oxidative stress indirectly mediated through its complex with Cu(II).

    PubMed

    Hasinoff, Brian B; Yadav, Arun A; Patel, Daywin; Wu, Xing

    2014-08-01

    Elesclomol is an anticancer drug that is currently undergoing clinical trials. Elesclomol forms a strong 1:1 complex with Cu(II) and may exert its anticancer activity through the induction of oxidative stress and/or its ability to transport copper into the cell. A UV-vis spectrophotometric titration showed that Cu(I) also formed a 1:1 complex with elesclomol. Ascorbic acid, but not glutathione or NADH, potently reduced the Cu(II)-elesclomol complex to produce hydrogen peroxide. Even though hydrogen peroxide mediated reoxidation of the copper(I) produced by ascorbic acid reduction has the potential to lead to hydroxyl radical formation, electron paramagnetic resonance spin trapping experiments, either with or without added hydrogen peroxide, showed that the ascorbic acid-reduced Cu(II)-elesclomol complex could not directly generate damaging hydroxyl radicals. Both Cu(II)-elesclomol and elesclomol potently oxidized dichlorofluorescin in K562 cells. The highly specific copper chelators tetrathiomolybdate and triethylenetetramine were found to greatly reduce the cytotoxicity of both elesclomol and Cu(II)-elesclomol complex towards erythroleukemic K562 cells, consistent with a role for copper in the cytotoxicity of elesclomol. The superoxide dismutating activity of Cu(II)-elesclomol was much lower than that of Cu(II). Depletion of glutathione levels in K562 cells by treatment with buthionine sulfoximine sensitized cells to both elesclomol and Cu(II)-elesclomol. In conclusion, these results showed that elesclomol indirectly inhibited cancer cell growth through Cu(II)-mediated oxidative stress. PMID:24798374

  15. Defective female reproductive function in 1,25(OH)2D-deficient mice results from indirect effect mediated by extracellular calcium and/or phosphorus.

    PubMed

    Sun, Weiwei; Xie, Hui; Ji, Ji; Zhou, Xiaojie; Goltzman, David; Miao, Dengshun

    2010-12-01

    We used mice with targeted deletion of 25-hydroxyvitamin D 1α-hydroxylase [1α(OH)ase(-/-)] to investigate the effects of calcium and phosphorus on defects in the reproductive system of 1,25-dihydroxyvitamin D [1,25(OH)(2)D]-deficient female mice. The 1α(OH)ase(-/-) mice and their wild-type littermates were fed either a normal diet or a rescue diet (high calcium, phosphate, and lactose) starting from weaning until 3 mo of age. We then determined serum calcium and phosphorus levels, assessed gonadotropin and gonadal hormone production, and evaluated folliculogenesis, corpus luteum formation, ovarian angiogenesis, uterus development, and fertility. Results showed that hypocalcemic and hypophosphatemic female 1α(OH)ase(-/-) mice developed infertility accompanied by decreased estrogen and progestogen levels, elevated follicle-stimulating hormone and luteinizing hormone levels, defects in follicular development and corpus luteum formation, uterine hypoplasia, and decreased ovarian expression of angiogenic factors including vascular endothelial growth factor (VEGF), angiopoietin-1 and -2, and Tie-2. When serum calcium and phosphorus were normalized by the rescue diet, the defective reproductive phenotype in the female 1α(OH)ase(-/-) mice, including the dysfunction in the hypothalamic-pituitary-ovarian axis, and ovarian angiogenesis were reversed. These results indicate that the infertility seen in 1,25(OH)(2)D-deficient mice is not a direct effect of active vitamin D deficiency on the reproductive system but is an indirect effect mediated by extracellular calcium and phosphorus.

  16. 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

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

    PubMed

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

    2015-02-01

    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.

  18. 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.

  19. 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.

  20. FOXO1 mediates RANKL-induced osteoclast formation and activity.

    PubMed

    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

    2015-03-15

    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 small interfering RNA. The receptor activator for NF-κB ligand (RANKL), a principal bone-resorbing factor, induced FOXO1 expression and nuclear localization 2 d after stimulation in bone marrow macrophages 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(+)FOXO1(L/L)) compared with matched controls (LyzM.Cre(-)FOXO1(L/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, ATP6vod2, cathepsin K, and integrin αv. Lastly, FOXO1 deletion reduced M-CSF-induced RANK expression and migration of osteoclast precursors. In the present study, we provide 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 because FOXO1 and RANKL are elevated in osteolytic conditions.

  1. The C-terminus of the {gamma}2 chain but not of the {beta}3 chain of laminin-332 is indirectly but indispensably necessary for integrin-mediated cell reactions

    SciTech Connect

    Navdaev, Alexei; Heitmann, Vanessa; Santana Evangelista, Karla de; Moergelin, Matthias; Wegener, Joachim; Eble, Johannes A.

    2008-02-01

    Using a recombinant mini-laminin-332, we showed that truncation of the three C-terminal amino acids of the {gamma}2 chain, but not of the C-terminal amino acid of the {beta}3 chain, completely abolished {alpha}3{beta}1 integrin binding and its cellular functions, such as attachment and spreading. However, a synthetic peptide mimicking the {gamma}2 chain C-terminus did not interfere with {alpha}3{beta}1 integrin binding or cell adhesion and spreading on laminin-332 as measured by protein interaction assays and electric cell-substrate impedance sensing. Nor was the soluble peptide able to restore the loss of integrin-mediated cell adhesiveness to mini-laminin-332 after deletion of the {gamma}2 chain C-terminus. These findings spoke against the hypothesis that the {gamma}2 chain C-terminus of laminin-332 is a part of the {alpha}3{beta}1 integrin interaction site. In addition, structural studies with electron microscopy showed that truncation of the {gamma}2 chain C-terminus opened up the compact supradomain structure of LG1-3 domains. Thus, by inducing or stabilizing an integrin binding-competent conformation or array of the LG1-3 domains, the {gamma}2 chain C-terminus plays an indirect but essential role in laminin-332 recognition by {alpha}3{beta}1 integrin and, hence, its cellular functions.

  2. Caspase-12 mediates carbon tetrachloride-induced hepatocyte apoptosis in mice

    PubMed Central

    Liu, Hua; Wang, Zhe; Nowicki, Michael J

    2014-01-01

    AIM: To investigate the role of caspase-12 and its downstream targets in carbon tetrachloride (CCl4)-induced hepatocyte apoptosis. METHODS: The role of caspase-12 was determined by using caspase-12 knock-out (-/-) mice. CCl4 (300 μL/kg body weight) or vehicle (corn oil) was administered to caspase-12+/+ or caspase-12-/- mice as a single intraperitoneal injection. The animals were sacrificed 24 h after the CCl4 treatment. Blood was collected to evaluate liver function by the measurement of the activity of alanine aminotransferase. Liver samples were used for the measurements of reactive oxygen species using plasma malondialdehyde as biomarker, hepatocyte apoptosis was evaluated via terminal transferase-mediated dUTP nick-end labeling and controlled by morphologic study, and cytochrome C release and caspase activations were measured by Western blotting. RESULTS: Administration of a low dose of CCl4 resulted in hepatocyte apoptosis and acute liver injury in wild-type mice. CCl4 also induced the generation of reactive oxygen species and induction of endoplasmic reticulum stress in the liver followed by activations of caspase-12, -9 and -3 as well as release of small amounts of cytochrome C. However, in the CCl4-treated caspase-12-/- mice, activation of caspase-9 and -3 were significantly attenuated (P < 0.05); no effect was seen in cytochrome C release. CCl4-induced apoptosis and liver damage was markedly reduced in caspase-12-/- mice compared to caspase-12+/+ mice (P < 0.05). The active form of caspase-8 was not detected in either caspase-12+/+ or caspase-12-/- mice. There was no significant different in the formation of reactive oxygen species in the livers of caspase-12+/+ and caspase-12-/- mice treated with CCl4. CONCLUSION: Caspase-12 plays a pivotal role in CCl4-induced hepatic apoptosis through the activation of the downstream effector caspase-3 directly and/or indirectly via capase-9 activation. PMID:25561786

  3. Activated human platelets induce factor XIIa-mediated contact activation.

    PubMed

    Bäck, Jennie; Sanchez, Javier; Elgue, Graciela; Ekdahl, Kristina Nilsson; Nilsson, Bo

    2010-01-01

    Earlier studies have shown that isolated platelets in buffer systems can promote activation of FXII or amplify contact activation, in the presence of a negatively charge substance or material. Still proof is lacking that FXII is activated by platelets in a more physiological environment. In this study we investigate if activated platelets can induce FXII-mediated contact activation and whether this activation affects clot formation in human blood. Human platelets were activated with a thrombin receptor-activating peptide, SFLLRN-amide, in platelet-rich plasma or in whole blood. FXIIa and FXIa in complex with preferentially antithrombin (AT) and to some extent C1-inhibitor (C1INH) were generated in response to TRAP stimulation. This contact activation was independent of surface-mediated contact activation, tissue factor pathway or thrombin. In clotting whole blood FXIIa-AT and FXIa-AT complexes were specifically formed, demonstrating that AT is a potent inhibitor of FXIIa and FXIa generated by platelet activation. Contact activation proteins were analyzed by flow cytometry and FXII, FXI, high-molecular weight kininogen, and prekallikrein were detected on activated platelets. Using chromogenic assays, enzymatic activity of platelet-associated FXIIa, FXIa, and kallikrein were demonstrated. Inhibition of FXIIa in non-anticoagulated blood also prolonged the clotting time. We conclude that platelet activation triggers FXII-mediated contact activation on the surface and in the vicinity of activated platelets. This leads specifically to generation of FXIIa-AT and FXIa-AT complexes, and contributes to clot formation. Activated platelets may thereby constitute an intravascular locus for contact activation, which may explain the recently reported importance of FXII in thrombus formation. PMID:19878657

  4. Chondroitin sulfate-E mediates estrogen-induced osteoanabolism

    PubMed Central

    Koike, Toshiyasu; Mikami, Tadahisa; Shida, Miharu; Habuchi, Osami; Kitagawa, Hiroshi

    2015-01-01

    Osteoporosis is an age-related disorder of bone remodeling in which bone resorption outstrips bone matrix deposition. Although anticatabolic agents are frequently used as first-line therapies for osteoporosis, alternative anabolic strategies that can enhance anabolic, osteogenic potential are actively sought. Sex steroid hormones, particularly estrogens, are bidirectional regulators for bone homeostasis; therefore, estrogen-mediated events are important potential targets for such anabolic therapies. Here, we show that estrogen-induced, osteoanabolic effects were mediated via enhanced production of chondroitin sulfate-E (CS-E), which could act as an osteogenic stimulant in our cell-based system. Conversely, estrogen deficiency caused reduced expression of CS-E-synthesizing enzymes, including GalNAc4S-6ST, and led to decreased CS-E production in cultures of bone marrow cells derived from ovariectomized mice. Moreover, Galnac4s6st-deficient mice had abnormally low bone mass that resulted from impaired osteoblast differentiation. These results indicated that strategies aimed at boosting CS-E biosynthesis are promising alternative therapies for osteoporosis. PMID:25759206

  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 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

  7. 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

  8. 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

  9. Environmental Estrogens Induce Mast Cell Degranulation and Enhance IgE-Mediated Release of Allergic Mediators

    PubMed Central

    Narita, Shin-ichiro; Goldblum, Randall M.; Watson, Cheryl S.; Brooks, Edward G.; Estes, D. Mark; Curran, Edward M.; Midoro-Horiuti, Terumi

    2007-01-01

    Background Prevalence and morbidity of allergic diseases have increased over the last decades. Based on the recently recognized differences in asthma prevalence between the sexes, we have examined the effect of endogenous estrogens on a key element of the allergic response. Some lipophilic pollutants have estrogen-like activities and are termed environmental estrogens. These pollutants tend to degrade slowly in the environment and to bioaccumulate and bioconcentrate in the food chain; they also have long biological half-lives. Objectives Our goal in this study was to identify possible pathogenic roles for environmental estrogens in the development of allergic diseases. Methods We screened a number of environmental estrogens for their ability to modulate the release of allergic mediators from mast cells. We incubated a human mast cell line and primary mast cell cultures derived from bone marrow of wild type and estrogen receptor α (ER-α )–deficient mice with environmental estrogens with and without estradiol or IgE and allergens. We assessed degranulation of mast cells by quantifying the release of β -hexosaminidase. Results All of the environmental estrogens tested caused rapid, dose-related release of β -hexosaminidase from mast cells and enhanced IgE-mediated release. The combination of physiologic concentrations of 17β -estradiol and several concentrations of environmental estrogens had additive effects on mast cell degranulation. Comparison of bone marrow mast cells from ER-α –sufficient and ER-α –deficient mice indicated that much of the effect of environmental estrogens was mediated by ER-α . Conclusions Our findings suggest that estrogenic environmental pollutants might promote allergic diseases by inducing and enhancing mast cell degranulation by physiologic estrogens and exposure to allergens. PMID:17366818

  10. IGFBP-3 mediates p53-induced apoptosis during serum starvation.

    PubMed

    Grimberg, Adda; Liu, Bingrong; Bannerman, Peter; El-Deiry, Wafik S; Cohen, Pinchas

    2002-08-01

    Insulin-like growth factor binding protein (IGFBP)-3, a p53-response gene, can induce apoptosis in an IGF-independent manner. Here we demonstrate that IGFBP-3 mediates p53-induced apoptosis during serum starvation using two foil neoplastic cell models: one which introduces p53 activity and one which eliminates it. We created a doxycycline-inducible p53 model from the p53-negative PC-3 prostate cancer cell line. Doxycycline treatment increased both p53 and IGFBP-3 levels. It also augmented apoptosis, but not during insulin-like growth factor-I co-treatment. In a second model, lung carcinoma H460 cells expressing fully functional p53 were stably transfected with E6, which targets p53 for degradation. H460-E6 cells contained less p53 and IGFBP-3 than control neo-transfected cells, and proteasome blockade restored both. In serum deprivation, H460-E6 cells had enhanced growth and less apoptosis than did H460-neo cells. Reductions in H460-neo apoptosis, comparable in magnitude to H460-E6, were achieved by adding anti-IGFBP-3-antibody or IGFBP-3 antisense oligomers, but not non-specific immunoglobulin or IGFBP-3 sense oligomers. In summary, turning p53 in two foil neoplastic cell models induced IGFBP-3 expression and increased apoptosis during serum starvation, an effect inhibited by insulin-like growth factor-I treatment and specific IGFBP-3 blockade. This is the first demonstration of inhibition of p53 action by antagonizing IGFBP-3.

  11. 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

  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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  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. 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

  20. 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

  1. 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.

  2. 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

  3. Musashi mediates translational repression of the Drosophila hypoxia inducible factor.

    PubMed

    Bertolin, Agustina P; Katz, Maximiliano J; Yano, Masato; Pozzi, Berta; Acevedo, Julieta M; Blanco-Obregón, Dalmiro; Gándara, Lautaro; Sorianello, Eleonora; Kanda, Hiroshi; Okano, Hideyuki; Srebrow, Anabella; Wappner, Pablo

    2016-09-19

    Adaptation to hypoxia depends on a conserved α/β heterodimeric transcription factor called Hypoxia Inducible Factor (HIF), whose α-subunit is regulated by oxygen through different concurrent mechanisms. In this study, we have identified the RNA binding protein dMusashi, as a negative regulator of the fly HIF homologue Sima. Genetic interaction assays suggested that dMusashi participates of the HIF pathway, and molecular studies carried out in Drosophila cell cultures showed that dMusashi recognizes a Musashi Binding Element in the 3' UTR of the HIFα transcript, thereby mediating its translational repression in normoxia. In hypoxic conditions dMusashi is downregulated, lifting HIFα repression and contributing to trigger HIF-dependent gene expression. Analysis performed in mouse brains revealed that murine Msi1 protein physically interacts with HIF-1α transcript, suggesting that the regulation of HIF by Msi might be conserved in mammalian systems. Thus, Musashi is a novel regulator of HIF that inhibits responses to hypoxia specifically when oxygen is available.

  4. Musashi mediates translational repression of the Drosophila hypoxia inducible factor

    PubMed Central

    Bertolin, Agustina P.; Katz, Maximiliano J.; Yano, Masato; Pozzi, Berta; Acevedo, Julieta M.; Blanco-Obregón, Dalmiro; Gándara, Lautaro; Sorianello, Eleonora; Kanda, Hiroshi; Okano, Hideyuki; Srebrow, Anabella; Wappner, Pablo

    2016-01-01

    Adaptation to hypoxia depends on a conserved α/β heterodimeric transcription factor called Hypoxia Inducible Factor (HIF), whose α-subunit is regulated by oxygen through different concurrent mechanisms. In this study, we have identified the RNA binding protein dMusashi, as a negative regulator of the fly HIF homologue Sima. Genetic interaction assays suggested that dMusashi participates of the HIF pathway, and molecular studies carried out in Drosophila cell cultures showed that dMusashi recognizes a Musashi Binding Element in the 3′ UTR of the HIFα transcript, thereby mediating its translational repression in normoxia. In hypoxic conditions dMusashi is downregulated, lifting HIFα repression and contributing to trigger HIF-dependent gene expression. Analysis performed in mouse brains revealed that murine Msi1 protein physically interacts with HIF-1α transcript, suggesting that the regulation of HIF by Msi might be conserved in mammalian systems. Thus, Musashi is a novel regulator of HIF that inhibits responses to hypoxia specifically when oxygen is available. PMID:27141964

  5. Multiple hormone-inducible enhancers as mediators of differential transcription.

    PubMed Central

    Toohey, M G; Morley, K L; Peterson, D O

    1986-01-01

    Sets of genes under a common regulatory control in a given cell type are often differentially transcribed. The possibility that this differential transcription can be modulated by the number or strength of cis-acting regulatory sequences associated with a given gene was tested by using the glucocorticoid-responsive enhancer element associated with the mouse mammary tumor virus promoter. Results indicate that differential levels of hormone-inducible gene expression can be modulated in an additive way by the number of glucocorticoid-responsive enhancers associated with this promoter. Realization of these effects shows little preference for position of the additional elements with respect to the promoter. When sequences that bind the glucocorticoid receptor in vitro with somewhat lower affinity than the enhancer were tested, these additive effects were not detected. The results support that differential transcription of genes subject to a common regulatory control can be mediated, at least in part, by the number or strength of their associated cis-acting regulatory sequences. Images PMID:3025659

  6. Aryl hydrocarbon receptor mediates benzene-induced hematotoxicity.

    PubMed

    Yoon, Byung-Il; Hirabayashi, Yoko; Kawasaki, Yasushi; Kodama, Yukio; Kaneko, Toyozo; Kanno, Jun; Kim, Dae-Yong; Fujii-Kuriyama, Yoshiaki; Inoue, Tohru

    2002-11-01

    Benzene can induce hematotoxicity and leukemia in humans and mice. Since a review of the literature shows that the CYP2E1 knockout mouse is not known to possess any benzene toxicity, the metabolism of benzene by CYP2E1 in the liver is regarded to be prerequisite for its cytotoxicity and genotoxicity, although the mechanism is not fully understood yet. Because it was found some years ago that benzene was also a substrate for CYP1A1, we investigated the involvement of the aryl hydrocarbon receptor (AhR) in benzene hematotoxicity using AhR wild-type (AhR(+/+)), heterozygous (AhR(+/-)), and homozygous (AhR(-/-)) male mice. Interestingly, following a 2-week inhalation of 300 ppm benzene (a potent dose for leukemogenicity), no hematotoxicity was induced in AhR(-/-) mice. Further, there were no changes in cellularity of peripheral blood and bone marrow (BM), nor in levels of granulocyte-macrophage colony-forming units in BM. This lack of hematotoxicity was associated with the lack of p21 overexpression, which was regularly seen in the wild-type mice following benzene inhalation. Combined treatment with two major benzene metabolites, phenol and hydroquinone, induced hemopoietic toxicity, although it was not known whether this happened due to a surprising lack of expression of CYP2E1 by AhR knockout, or due to a lack of other AhR-mediated CYP enzymes, including 1A1 (i.e., a possible alternative pathway of benzene metabolism). The former possibility, evaluated in the present study, failed to show a significant relationship between AhR and the expression of CYP2E1. Furthermore, a subsequent evaluation of AhR expression after benzene inhalation tended to show higher but less significant expression in the liver, and none in the BM, compared with sham control. Although this study failed to identify the more likely of the above-mentioned two possibilities, the study using AhR knockout mice on benzene inhalation presents the unique possibility that the benzene toxicity may be

  7. 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.

  8. 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.

  9. Density matrix description of laser-induced hot electron mediated photodesorption of NO from Pt(111)

    NASA Astrophysics Data System (ADS)

    Saalfrank, Peter; Baer, Roi; Kosloff, Ronnie

    1994-12-01

    Based on the numerical solution of the Liouville-von Neumann equation for dissipative systems, the photodesorption dynamics of NO/Pt(111) are studied. Dissipative terms are used to describe the quenching of electronically excited states on the metal, electronic dephasing and the indirect (hot-electron mediated) excitation processes in the DIMET and DIET limits. Norm and energy flow, desorption probabilities and density time-of-flight spectra are computed.

  10. 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

  11. Neuropeptide Y and extracellular signal-regulated kinase mediate injury-induced neuroregeneration in mouse olfactory epithelium

    PubMed Central

    Jia, Cuihong; Hegg, Colleen Cosgrove

    2011-01-01

    In the olfactory epithelium (OE), injury induces ATP release, and subsequent activation of P2 purinergic receptors by ATP promotes neuroregeneration by increasing basal progenitor cell proliferation. The molecular mechanisms underlying ATP-induced increases in OE neuroregeneration have not been established. In the present study, the roles of neuroproliferative factors neuropeptide Y (NPY) and fibroblast growth factor2 (FGF2), and p44/42 extracellular signal-regulated kinase (ERK) on ATP-mediated increases of neuroregeneration in the OE were investigated. ATP increased basal progenitor cell proliferation in the OE via activation of P2 purinergic receptors in vitro and in vivo as monitored by incorporation of 5′-ethynyl-2′-deoxyuridine, a thymidine analog, into DNA, and proliferating cell nuclear antigen (PCNA) protein levels. ATP induced p44/42 ERK activation in globose basal cells (GBC) but not horizontal basal cells (HBC). ATP differentially regulated p44/42 ERK over time in the OE both in vitro and in vivo with transient inhibition (5–15 min) followed by activation (30 min – 1 hr) of p44/42 ERK. In addition, ATP indirectly activated p44/42 ERK in the OE via ATP-induced NPY release and subsequent activation of NPY Y1 receptors in the basal cells. There were no synergistic effects of ATP and NPY or FGF2 on OE neuroregeneration. These data clearly have implications for the pharmacological modulation of neuroregeneration in the olfactory epithelium. PMID:22154958

  12. 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

  13. 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

  14. Luminal leptin induces rapid inhibition of active intestinal absorption of glucose mediated by sodium-glucose cotransporter 1.

    PubMed

    Ducroc, Robert; Guilmeau, Sandra; Akasbi, Khalil; Devaud, Hélène; Buyse, Marion; Bado, André

    2005-02-01

    The effect of leptin on glucose transport was studied in rat jejunal mucosa in Ussing chambers. Leptin was added in the luminal or the serosal compartment before the tissues were challenged with 1, 10, or 50 mmol/l glucose. In response to 10 mmol/l glucose, the increase in short-circuit current (DeltaIsc) reached 26.8 +/- 2.1 microA/cm(2). Luminal addition of leptin dramatically decreased glucose-induced Isc (90.5% for 10 nmol/l leptin). Inhibition was maximal after 5 min and dose dependent (IC(50) = 0.13 nM). Western blot analysis showed that rapid inhibition of glucose-induced Isc by leptin was associated with a parallel decrease in the abundance of sodium-glucose transporter-1 in brush border membranes. Inhibition by luminal leptin of DeltaIsc was prevented by inhibitor of conventional protein kinase C isoforms. Serosal addition of leptin did not decrease glucose-induced Isc within 5 min and reached maximum after 10 min. The effect of leptin from serosal side was blocked by cholecystokinin (CCK) receptor-2 receptor antagonist YM022. Altogether, these data demonstrate that luminal leptin induces rapid inhibition of glucose entry into enterocyte. The slower action of leptin on the serosal side of mucosa seems indirect and is likely mediated by endogenous CCK. They demonstrate that gut leptin is a major regulator of rapid intestinal glucose transport.

  15. 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

  16. 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.

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

    PubMed Central

    Hua, Guoqiang; Paulen, Laetitia; Chambon, Pierre

    2016-01-01

    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

  18. 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.

  19. A suicidal DNA vaccine expressing the fusion protein of peste des petits ruminants virus induces both humoral and cell-mediated immune responses in mice.

    PubMed

    Wang, Yong; Yue, Xiaolin; Jin, Hongyan; Liu, Guangqing; Pan, Ling; Wang, Guijun; Guo, Hao; Li, Gang; Li, Yongdong

    2015-12-01

    Peste des petits ruminants (PPR), a highly contagious disease induced by PPR virus (PPRV), affects sheep and goats. PPRV fusion (F) protein is important for the induction of immune responses against PPRV. We constructed a Semliki Forest virus (SFV) replicon-vectored DNA vaccine ("suicidal DNA vaccine") and evaluated its immunogenicity in BALB/c mice. The F gene of PPRV was cloned and inserted into the SFV replicon-based vector pSCA1. The antigenicity of the resultant plasmid pSCA1/F was identified by indirect immunofluorescence and western blotting. BALB/c mice were then intramuscularly injected with pSCA1/F three times at 14-d intervals. Specific antibodies and virus-neutralizing antibodies against PPRV were quantified by indirect ELISA and microneutralization tests, respectively. Cell-mediated immune responses were examined by cytokine and lymphocyte proliferation assays. The pSCA1/F expressed F protein in vitro and induced specific and neutralizing antibody production, and lymphocyte proliferation in mice. Mice vaccinated with pSCA1/F had increased IL-2 and IL-10 levels after 24-h post first immunization. IFN-γ and TNF-α levels increased from that time point and gradually decreased thereafter. Thus, the Semliki Forest virus replicon-vectored DNA vaccine expressing the F protein of PPRV induced both humoral and cell-mediated immune responses in mice. This could be considered as a novel strategy for vaccine development against PPR. PMID:26343487

  20. A suicidal DNA vaccine expressing the fusion protein of peste des petits ruminants virus induces both humoral and cell-mediated immune responses in mice.

    PubMed

    Wang, Yong; Yue, Xiaolin; Jin, Hongyan; Liu, Guangqing; Pan, Ling; Wang, Guijun; Guo, Hao; Li, Gang; Li, Yongdong

    2015-12-01

    Peste des petits ruminants (PPR), a highly contagious disease induced by PPR virus (PPRV), affects sheep and goats. PPRV fusion (F) protein is important for the induction of immune responses against PPRV. We constructed a Semliki Forest virus (SFV) replicon-vectored DNA vaccine ("suicidal DNA vaccine") and evaluated its immunogenicity in BALB/c mice. The F gene of PPRV was cloned and inserted into the SFV replicon-based vector pSCA1. The antigenicity of the resultant plasmid pSCA1/F was identified by indirect immunofluorescence and western blotting. BALB/c mice were then intramuscularly injected with pSCA1/F three times at 14-d intervals. Specific antibodies and virus-neutralizing antibodies against PPRV were quantified by indirect ELISA and microneutralization tests, respectively. Cell-mediated immune responses were examined by cytokine and lymphocyte proliferation assays. The pSCA1/F expressed F protein in vitro and induced specific and neutralizing antibody production, and lymphocyte proliferation in mice. Mice vaccinated with pSCA1/F had increased IL-2 and IL-10 levels after 24-h post first immunization. IFN-γ and TNF-α levels increased from that time point and gradually decreased thereafter. Thus, the Semliki Forest virus replicon-vectored DNA vaccine expressing the F protein of PPRV induced both humoral and cell-mediated immune responses in mice. This could be considered as a novel strategy for vaccine development against PPR.

  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. 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.

  3. Inhibition of clathrin-mediated endocytosis prevents amyloid β-induced axonal damage.

    PubMed

    Kuboyama, Tomoharu; Lee, Young-A; Nishiko, Hiroaki; Tohda, Chihiro

    2015-05-01

    Amyloid β (Aβ)-induced axonal degeneration is a major cause of Alzheimer's disease (AD) pathology. However, the critical target to prevent Aβ-induced axonal degeneration remains unknown. Here, we analyzed growth cone collapse elicited by Aβ, a putative early Aβ-induced event in axons. Although no study has yet shown influence of Aβ on the growth cone, we first visualized Aβ-initiated growth cone collapse in cultured neurons. Furthermore, we determined that the collapse was triggered by clathrin-mediated endocytosis probably via Aβ-Ca(2+) signaling. The inhibition of clathrin-mediated endocytosis prevented Aβ-induced axonal loss both in vitro and in vivo and prevented memory impairment in an AD mouse model. Our results clarified the important role of clathrin-mediated endocytosis in Aβ-induced collapse of growth cone that leads to axonal degeneration and memory impairment.

  4. 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

  5. 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.

  6. Redox-Mediated and Ionizing-Radiation-Induced Inflammatory Mediators in Prostate Cancer Development and Treatment

    PubMed Central

    Miao, Lu; Holley, Aaron K.; Zhao, Yanming; St. Clair, William H.

    2014-01-01

    Abstract Significance: Radiation therapy is widely used for treatment of prostate cancer. Radiation can directly damage biologically important molecules; however, most effects of radiation-mediated cell killing are derived from the generated free radicals that alter cellular redox status. Multiple proinflammatory mediators can also influence redox status in irradiated cells and the surrounding microenvironment, thereby affecting prostate cancer progression and radiotherapy efficiency. Recent Advances: Ionizing radiation (IR)–generated oxidative stress can regulate and be regulated by the production of proinflammatory mediators. Depending on the type and stage of the prostate cancer cells, these proinflammatory mediators may lead to different biological consequences ranging from cell death to development of radioresistance. Critical Issues: Tumors are heterogeneous and dynamic communication occurs between stromal and prostate cancer cells, and complicated redox-regulated mechanisms exist in the tumor microenvironment. Thus, antioxidant and anti-inflammatory strategies should be carefully evaluated for each patient at different stages of the disease to maximize therapeutic benefits while minimizing unintended side effects. Future Directions: Compared with normal cells, tumor cells are usually under higher oxidative stress and secrete more proinflammatory mediators. Thus, redox status is often less adaptive in tumor cells than in their normal counterparts. This difference can be exploited in a search for new cancer therapeutics and treatment regimes that selectively activate cell death pathways in tumor cells with minimal unintended consequences in terms of chemo- and radio-resistance in tumor cells and toxicity in normal tissues. Antioxid. Redox Signal. 20, 1481–1500. PMID:24093432

  7. 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.

  8. Optical band gap transition from direct to indirect induced by organic content of CH3NH3PbI3 perovskite films

    NASA Astrophysics Data System (ADS)

    Ke, Xiaohan; Yan, Jun; Zhang, Ao; Zhang, Bing; Chen, Yunlin

    2015-08-01

    Most of the systematic studies on tuning the band gap in the family of organolead halide perovskites have focused on changing the compositions of halogens. Here, the effects of varying the organic content on the band gap of CH3NH3PbI3 were studied. The methylammonium lead iodide (CH3NH3PbI3) films were fabricated with different molar ratios of CH3NH3I to PbI2. We found that the films become compact and the crystalline size decreased from 6.0 to 0.2 μm and the optical band gap of CH3NH3PbI3 could be transferred from direct to indirect with increasing CH3NH3I content in the precursor. The experimental results demonstrated that the existence of the indirect band gap in CH3NH3PbI3 film and the CH3NH3I content plays a key role in adjusting the film morphology and optical band. The investigation of the optical band transition induced by changing organic content could provide a different view on studying CH3NH3PbI3 materials.

  9. Indirect Effects and Infants' Reaction to Strangers.

    ERIC Educational Resources Information Center

    Feiring, Candice; And Others

    1984-01-01

    Examined whether an infant's reaction to a stranger would be indirectly influenced by the infant observing a stranger-third party interaction. Subjects were 45 15-month-old infants. Results suggest indirect effects influence social interactions and show that significant others can play an important role in mediating these effects. (Author/RH)

  10. Ionizing radiation and restriction enzymes induce microhomology-mediated illegitimate recombination in Saccharomyces cerevisiae.

    PubMed

    Chan, Cecilia Y; Kiechle, Markus; Manivasakam, Palaniyandi; Schiestl, Robert H

    2007-01-01

    DNA double-strand breaks can be repaired by illegitimate recombination without extended sequence homology. A distinct mechanism namely microhomology-mediated recombination occurs between a few basepairs of homology that is associated with deletions. Ionizing radiation and restriction enzymes have been shown to increase the frequency of nonhomologous integration in yeast. However, the mechanism of such enhanced recombination events is not known. Here, we report that both ionizing radiation and restriction enzymes increase the frequency of microhomology-mediated integration. Irradiated yeast cells displayed 77% microhomology-mediated integration, compared to 27% in unirradiated cells. Radiation-induced integration exhibited lack of deletions at genomic insertion sites, implying that such events are likely to occur at undamaged sites. Restriction enzymes also enhanced integration events at random non-restriction sites via microhomology-mediated recombination. Furthermore, generation of a site-specific I-SceI-mediated double-strand break induces microhomology-mediated integration randomly throughout the genome. Taken together, these results suggest that double-strand breaks induce a genome-wide microhomology-mediated illegitimate recombination pathway that facilitates integration probably in trans at non-targeted sites and might be involved in generation of large deletions and other genomic rearrangements.

  11. 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.

  12. 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.

  13. An Intergenic Regulatory Region Mediates Drosophila Myc -Induced Apoptosis and Blocks Tissue Hyperplasia

    PubMed Central

    Zhang, Can; Tintó, Sergio Casas; Li, Guangyao; Lin, Nianwei; Chung, Michelle; Moreno, Eduardo; Moberg, Kenneth H.; Zhou, Lei

    2014-01-01

    Induction of cell autonomous apoptosis following oncogene-induced overproliferation is a major tumor-suppressive mechanism in vertebrates. However the detailed mechanism mediating this process remains enigmatic. In this study we demonstrate that dMyc-induced cell-autonomous apoptosis in the fruit fly Drosophila melanogaster relies on an intergenic sequence termed the IRER (Irradiation Responsive Enhancer Region). The IRER mediates expression of surrounding pro-apoptotic genes, and we use an in vivo reporter of the IRER chromatin state to gather evidence that epigenetic control of DNA accessibility within the IRER is an important determinant of the strength of this response to excess dMyc. In prior work we showed that the IRER also mediates P53-dependent induction of pro-apoptotic genes following DNA damage, and the chromatin conformation within IRER is regulated by Polycomb group-mediated histone modifications. dMyc-induced apoptosis and the P53-mediated DNA damage response thus overlap in a requirement for the IRER. The epigenetic mechanisms controlling IRER accessibility appear to set thresholds for the P53 and dMyc-induced expression of apoptotic genes in vivo and may have a profound impact on cellular sensitivity to oncogene-induced stress. PMID:24931167

  14. 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.

  15. Influenza virus induces apoptosis via BAD-mediated mitochondrial dysregulation.

    PubMed

    Tran, Anh T; Cortens, John P; Du, Qiujiang; Wilkins, John A; Coombs, Kevin M

    2013-01-01

    Influenza virus infection results in host cell death and major tissue damage. Specific components of the apoptotic pathway, a signaling cascade that ultimately leads to cell death, are implicated in promoting influenza virus replication. BAD is a cell death regulator that constitutes a critical control point in the intrinsic apoptosis pathway, which occurs through the dysregulation of mitochondrial outer membrane permeabilization and the subsequent activation of downstream apoptogenic factors. Here we report a novel proviral role for the proapoptotic protein BAD in influenza virus replication. We show that influenza virus-induced cytopathology and cell death are considerably inhibited in BAD knockdown cells and that both virus replication and viral protein production are dramatically reduced, which suggests that virus-induced apoptosis is BAD dependent. Our data showed that influenza viruses induced phosphorylation of BAD at residues S112 and S136 in a temporal manner. Viral infection also induced BAD cleavage, late in the viral life cycle, to a truncated form that is reportedly a more potent inducer of apoptosis. We further demonstrate that knockdown of BAD resulted in reduced cytochrome c release and suppression of the intrinsic apoptotic pathway during influenza virus replication, as seen by an inhibition of caspases-3, caspase-7, and procyclic acidic repetitive protein (PARP) cleavage. Our data indicate that influenza viruses carefully modulate the activation of the apoptotic pathway that is dependent on the regulatory function of BAD and that failure of apoptosis activation resulted in unproductive viral replication.

  16. 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.

  17. 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.

  18. PUMA mediates ER stress-induced apoptosis in portal hypertensive gastropathy.

    PubMed

    Tan, S; Wei, X; Song, M; Tao, J; Yang, Y; Khatoon, S; Liu, H; Jiang, J; Wu, B

    2014-03-13

    Mucosal apoptosis has been demonstrated to be an essential pathological feature in portal hypertensive gastropathy (PHG). p53-upregulated modulator of apoptosis (PUMA) was identified as a BH3-only Bcl-2 family protein that has an essential role in apoptosis induced by a variety of stimuli, including endoplasmic reticulum (ER) stress. However, whether PUMA is involved in mucosal apoptosis in PHG remains unclear, and whether PUMA induces PHG by mediating ER stress remains unknown. The aim of the study is to investigate whether PUMA is involved in PHG by mediating ER stress apoptotic signaling. To identify whether PUMA is involved in PHG by mediating ER stress, gastric mucosal injury and apoptosis were studied in both PHG patients and PHG animal models using PUMA knockout (PUMA-KO) and PUMA wild-type (PUMA-WT) mice. The induction of PUMA expression and ER stress signaling were investigated, and the mechanisms of PUMA-mediated apoptosis were analyzed. GES-1 and SGC7901 cell lines were used to further identify whether PUMA-mediated apoptosis was induced by ER stress in vitro. Epithelial apoptosis and PUMA were markedly induced in the gastric mucosa of PHG patients and mouse PHG models. ER stress had a potent role in the induction of PUMA and apoptosis in PHG models, and the apoptosis was obviously attenuated in PUMA-KO mice. Although the targeted deletion of PUMA did not affect ER stress, mitochondrial apoptotic signaling was downregulated in mice. Meanwhile, PUMA knockdown significantly ameliorated ER stress-induced mitochondria-dependent apoptosis in vitro. These results indicate that PUMA mediates ER stress-induced mucosal epithelial apoptosis through the mitochondrial apoptotic pathway in PHG, and that PUMA is a potentially therapeutic target for PHG.

  19. Octopamine mediates starvation-induced hyperactivity in adult Drosophila.

    PubMed

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

    2015-04-21

    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.

  20. 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

  1. Epigenetic Silencing Mediates Mitochondria Stress-induced Longevity

    PubMed Central

    Schroeder, Elizabeth A.; Raimundo, Nuno; Shadel, Gerald S.

    2013-01-01

    SUMMARY Reactive oxygen species (ROS) play complex roles in aging, having both damaging effects and signaling functions. Transiently elevating mitochondrial stress, including mitochondrial ROS (mtROS), elicits beneficial responses that extend lifespan. However, these adaptive, longevity-signaling pathways remain poorly understood. We show here that Tel1p and Rad53p, homologs of the mammalian DNA-damage-response kinases ATM and Chk2, mediate a hormetic mtROS longevity signal that extends yeast chronological lifespan. This pathway senses mtROS in a manner distinct from the nuclear DNA-damage response and ultimately imparts longevity by inactivating the histone demethylase Rph1p specifically at subtelomeric heterochromatin, enhancing binding of the silencing protein Sir3p, and repressing subtelomeric transcription. These results demonstrate the existence of conserved mitochondria-to-nucleus stress-signaling pathways that regulate aging through epigenetic modulation of nuclear gene expression. PMID:23747251

  2. Significance of neuronal cytochrome P450 activity in opioid-mediated stress-induced analgesia.

    PubMed

    Hough, Lindsay B; Nalwalk, Julia W; Yang, Weizhu; Ding, Xinxin

    2014-08-26

    Stressful environmental changes can suppress nociceptive transmission, a phenomenon known as "stress-induced analgesia". Depending on the stressor and the subject, opioid or non-opioid mechanisms are activated. Brain μ opioid receptors mediate analgesia evoked either by exogenous agents (e.g. morphine), or by the release of endogenous opioids following stressful procedures. Recent work with morphine and neuronal cytochrome P450 (P450)-deficient mice proposed a signal transduction role for P450 enzymes in µ analgesia. Since µ opioid receptors also mediate some forms of stress-induced analgesia, the present studies assessed the significance of brain P450 activity in opioid-mediated stress-induced analgesia. Two widely-used models of opioid stress-induced analgesia (restraint and warm water swim) were studied in both sexes of wild-type control and P450-deficient (Null) mice. In control mice, both stressors evoked moderate analgesic responses which were blocked by pretreatment with the opioid antagonist naltrexone, confirming the opioid nature of these responses. Consistent with literature, sex differences (control female>control male) were seen in swim-induced, but not restraint-induced, analgesia. Null mice showed differential responses to the two stress paradigms. As compared with control subjects, Null mice showed highly attenuated restraint-induced analgesia, showing a critical role for neuronal P450s in this response. However, warm water swim-induced analgesia was unchanged in Null vs. control mice. Additional control experiments confirmed the absence of morphine analgesia in Null mice. These results are the first to show that some forms of opioid-mediated stress-induced analgesia require brain neuronal P450 activity.

  3. SREBP-1 Mediates Angiotensin II-Induced TGF-β1 Upregulation and Glomerular Fibrosis

    PubMed Central

    Wang, Tony N.; Chen, Xing; Li, Renzhong; Gao, Bo; Mohammed-Ali, Zahraa; Lu, Chao; Yum, Victoria; Dickhout, Jeffrey G.

    2015-01-01

    Angiotensin II is an important mediator of CKD of diverse etiology. A common pathologic feature of CKD is glomerular fibrosis, a central mediator of which is the profibrotic cytokine TGF-β. The mechanisms underlying the induction of TGF-β and matrix by angiotensin II are not completely understood. Recent studies showed that overexpression of the transcription factor SREBP-1 induces glomerular sclerosis and that angiotensin II can activate SREBP-1 in tubular cells. We thus studied whether SREBP-1 is activated by angiotensin II and mediates angiotensin II–induced profibrogenic responses in primary rat mesangial cells. Treatment of cells with angiotensin II induced the upregulation and activation of SREBP-1. Angiotensin II–induced activation of SREBP-1 required signaling through the angiotensin II type I receptor and activation of PI3K/Akt in addition to the chaperone SCAP and protease S1P. Notably, angiotensin II-induced endoplasmic reticulum stress was identified as a key mediator of Akt-SREBP-1 activation, and inhibition of endoplasmic reticulum stress or SREBP-1 prevented angiotensin II–induced SREBP-1 binding to the TGF-β promoter, TGF-β upregulation, and downstream fibronectin upregulation. Endoplasmic reticulum stress alone, however, did not induce TGF-β upregulation despite activating SREBP-1. Although not required for SREBP-1 activation by angiotensin II, EGF receptor signaling was necessary for activation of the SREBP-1 cotranscription factor Sp1, which provided a required second signal for TGF-β upregulation. In vivo, endoplasmic reticulum stress and SREBP-1-dependent effects were induced in glomeruli of angiotensin II-infused mice, and administration of the SREBP inhibitor fatostatin prevented angiotensin II–induced TGF-β upregulation and matrix accumulation. SREBP-1 and endoplasmic reticulum stress thus provide potential novel therapeutic targets for the treatment of CKD. PMID:25398788

  4. The transcriptional coactivator PGC-1alpha mediates exercise-induced angiogenesis in skeletal muscle.

    PubMed

    Chinsomboon, Jessica; Ruas, Jorge; Gupta, Rana K; Thom, Robyn; Shoag, Jonathan; Rowe, Glenn C; Sawada, Naoki; Raghuram, Srilatha; Arany, Zoltan

    2009-12-15

    Peripheral arterial disease (PAD) affects 5 million people in the US and is the primary cause of limb amputations. Exercise remains the single best intervention for PAD, in part thought to be mediated by increases in capillary density. How exercise triggers angiogenesis is not known. PPARgamma coactivator (PGC)-1alpha is a potent transcriptional co-activator that regulates oxidative metabolism in a variety of tissues. We show here that PGC-1alpha mediates exercise-induced angiogenesis. Voluntary exercise induced robust angiogenesis in mouse skeletal muscle. Mice lacking PGC-1alpha in skeletal muscle failed to increase capillary density in response to exercise. Exercise strongly induced expression of PGC-1alpha from an alternate promoter. The induction of PGC-1alpha depended on beta-adrenergic signaling. beta-adrenergic stimulation also induced a broad program of angiogenic factors, including vascular endothelial growth factor (VEGF). This induction required PGC-1alpha. The orphan nuclear receptor ERRalpha mediated the induction of VEGF by PGC-1alpha, and mice lacking ERRalpha also failed to increase vascular density after exercise. These data demonstrate that beta-adrenergic stimulation of a PGC-1alpha/ERRalpha/VEGF axis mediates exercise-induced angiogenesis in skeletal muscle.

  5. Inducible resistance to Fas-mediated apoptosis in B cells.

    PubMed

    Rothstein, T L

    2000-12-01

    Apoptosis produced in B cells through Fas (APO-1, CD95) triggering is regulated by signals derived from other surface receptors: CD40 engagement produces upregulation of Fas expression and marked susceptibility to Fas-induced cell death, whereas antigen receptor engagement, or IL-4R engagement, inhibits Fas killing and in so doing induces a state of Fas-resistance, even in otherwise sensitive, CD40-stimulated targets. Surface immunoglobulin and IL-4R utilize at least partially distinct pathways to produce Fas-resistance that differentially depend on PKC and STAT6, respectively. Further, surface immunoglobulin signaling for inducible Fas-resistance bypasses Btk, requires NF-kappaB, and entails new macromolecular synthesis. Terminal effectors of B cell Fas-resistance include the known anti-apoptotic gene products, Bcl-xL and FLIP, and a novel anti-apoptotic gene that encodes FAIM (Fas Apoptosis Inhibitory Molecule). faim was identified by differential display and exists in two alternatively spliced forms; faim-S is broadly expressed, but faim-L expression is tissue-specific. The FAIM sequence is highly evolu- tionarily conserved, suggesting an important role for this molecule throughout phylogeny. Inducible resistance to Fas killing is hypothesized to protect foreign antigen-specific B cells during potentially hazardous interactions with FasL-bearing T cells, whereas autoreactive B cells fail to become Fas-resistant and are deleted via Fas-dependent cytotoxicity. Inadvertent or aberrant acquisition of Fas-resistance may permit autoreactive B cells to escape Fas deletion, and malignant lymphocytes to impede anti-tumor immunity.

  6. 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

  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.

  8. Gap Junction Intercellular Communication Mediates Ammonia-Induced Neurotoxicity.

    PubMed

    Bobermin, Larissa Daniele; Arús, Bernardo Assein; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Quincozes-Santos, André

    2016-02-01

    Astrocytes are important brain targets of ammonia, a neurotoxin implicated in the development of hepatic encephalopathy. During hyperammonemia, the pivotal role of astrocytes in brain function and homeostasis is impaired. These cells are abundantly interconnected by gap junctions (GJ), which are intercellular channels that allow the exchange of signaling molecules and metabolites. This communication may also increase cellular vulnerability during injuries, while GJ uncoupling could limit the extension of a lesion. Therefore, the current study was performed to investigate whether astrocyte coupling through GJ contributes to ammonia-induced cytotoxicity. We found that carbenoxolone (CBX), an effective GJ blocker, prevented the following effects induced by ammonia in astrocyte primary cultures: (1) decrease in cell viability and membrane integrity; (2) increase in reactive oxygen species production; (3) decrease in GSH intracellular levels; (4) GS activity; (5) pro-inflammatory cytokine release. On the other hand, CBX had no effect on C6 astroglial cells, which are poorly coupled via GJ. To our knowledge, this study provides the first evidence that GJ play a role in ammonia-induced cytotoxicity. Although more studies in vivo are required to confirm our hypothesis, our data suggest that GJ communication between astrocytes may transmit damage signals and excitotoxic components from unhealthy to normal cells, thereby contributing to the propagation of the neurotoxicity of ammonia. PMID:26646155

  9. Gap Junction Intercellular Communication Mediates Ammonia-Induced Neurotoxicity.

    PubMed

    Bobermin, Larissa Daniele; Arús, Bernardo Assein; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Quincozes-Santos, André

    2016-02-01

    Astrocytes are important brain targets of ammonia, a neurotoxin implicated in the development of hepatic encephalopathy. During hyperammonemia, the pivotal role of astrocytes in brain function and homeostasis is impaired. These cells are abundantly interconnected by gap junctions (GJ), which are intercellular channels that allow the exchange of signaling molecules and metabolites. This communication may also increase cellular vulnerability during injuries, while GJ uncoupling could limit the extension of a lesion. Therefore, the current study was performed to investigate whether astrocyte coupling through GJ contributes to ammonia-induced cytotoxicity. We found that carbenoxolone (CBX), an effective GJ blocker, prevented the following effects induced by ammonia in astrocyte primary cultures: (1) decrease in cell viability and membrane integrity; (2) increase in reactive oxygen species production; (3) decrease in GSH intracellular levels; (4) GS activity; (5) pro-inflammatory cytokine release. On the other hand, CBX had no effect on C6 astroglial cells, which are poorly coupled via GJ. To our knowledge, this study provides the first evidence that GJ play a role in ammonia-induced cytotoxicity. Although more studies in vivo are required to confirm our hypothesis, our data suggest that GJ communication between astrocytes may transmit damage signals and excitotoxic components from unhealthy to normal cells, thereby contributing to the propagation of the neurotoxicity of ammonia.

  10. Fructokinase activity mediates dehydration-induced renal injury

    PubMed Central

    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

    2014-01-01

    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. 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.

  12. Antibody-mediated modulation of arthritis induced by Chlamydia.

    PubMed Central

    Rank, R. G.; Ramsey, K. H.; Hough, A. J.

    1988-01-01

    The purpose of this investigation was to determine the role of the humoral immune response in the production of arthritis in mice immunized with the chlamydial agent of mouse pneumonitis (MoPn) (Chlamydia trachomatis biovar). Mice were made B cell deficient (BCD) by treatment with rabbit antiserum to murine IgM. Control mice included animals treated similarly with normal rabbit serum or phosphate-buffered saline. Male mice were immunized with MoPn inactivated with ultraviolet irradiation while female mice were immunized by genital tract infection with viable chlamydiae. Arthritis was elicited in all mice by intra-articular inoculation of inactivated MoPn. When knee joints were examined for pathologic changes at varying times after challenge, a marked enhancement of the arthritis was observed in both male and female BCD mice when compared with controls at all time points. These data indicated that the humoral immune response is not essential for the production of arthritic disease in this model but may have some role in the modulation of the process in immunologically intact animals. Persistence of chlamydial antigen in joint tissue of BCD mice suggested that antibody may play a role in the elimination of antigen, thus decreasing the stimulus for the development of cell-mediated immunologic injury. Regulatory role for T suppressor cells cannot be ruled out however, because B cell deficient mice have been shown to lack certain T suppressor cell subsets. Images Figure 3 Figure 4 Figure 6 Figure 7 Figure 9 PMID:3400779

  13. 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

  14. 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

  15. Lipid membrane-mediated attraction between curvature inducing objects

    PubMed Central

    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

  16. 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.

  17. 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

  18. P53-Mediated Repression of the Reprogramming in Cloned Bovine Embryos Through Direct Interaction with HDAC1 and Indirect Interaction with DNMT3A.

    PubMed

    Ma, P J; Zhang, H; Li, R; Wang, Y S; Zhang, Y; Hua, S

    2015-06-01

    P53 is a transcriptional activator, regulating growth arrest, DNA repair and apoptosis. We found that the expression level of P53 and the epigenetic profiles were significantly different in bovine somatic cell nuclear transfer embryos from those in vitro fertilization (IVF) embryos. So we inferred that abnormally expression of P53 might contribute to the incomplete reprogramming. Using bovine foetal fibroblasts, we constructed and screened a highly efficient shRNA vector targeting bovine P53 gene and then reconstituted somatic cell nuclear transfer embryos (RNAi-SCNT). The results indicated that expression levels of P53 were downregulated significantly in RNAi-SCNT embryos, and the blastulation rate and the total number of cell increased significantly. Moreover, methylation levels of CpG islands located 5' region of OCT4, NANOG, H19 and IGF2R in RNAi -SCNT embryos were significantly normalized to that IVF embryos, and the methylation levels of genome DNA, H3K9 and H4K5 acetylation levels were also returned to levels similar to the IVF embryos. Differentially expressed genes were identified by microarray, and 28 transcripts were found to be significantly different (> twofolds) in RNAi-SCNT embryos compared to the control nuclear transfer embryos (SCNT). Among the 28 differentially expressed transcripts, just HDAC1 and DNMT3A were closely associated with the epigenetic modifications. Finally, ChIP further showed that P53 might repress the epigenetic reprogramming by regulating HDAC1 directly and DNMT3A indirectly. These findings offer significant references to further elucidate the mechanism of epigenetic reprogramming in SCNT embryos.

  19. 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

  20. Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii.

    PubMed

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

    2016-04-16

    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.

  1. 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.

  2. 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

  3. BIM mediates oncogene inactivation-induced apoptosis in multiple transgenic mouse models of acute lymphoblastic leukemia

    PubMed Central

    Li, Yulin; Deutzmann, Anja; Choi, Peter S.; Fan, Alice C.; Felsher, Dean W.

    2016-01-01

    Oncogene inactivation in both clinical targeted therapies and conditional transgenic mouse cancer models can induce significant tumor regression associated with the robust induction of apoptosis. Here we report that in MYC-, RAS-, and BCR-ABL-induced acute lymphoblastic leukemia (ALL), apoptosis upon oncogene inactivation is mediated by the same pro-apoptotic protein, BIM. The induction of BIMin the MYC- and RAS-driven leukemia is mediated by the downregulation of miR-17-92. Overexpression of miR-17-92 blocked the induction of apoptosis upon oncogene inactivation in the MYC and RAS-driven but not in the BCR-ABL-driven ALL leukemia. Hence, our results provide novel insight into the mechanism of apoptosis upon oncogene inactivation and suggest that induction of BIM-mediated apoptosis may be an important therapeutic approach for ALL. PMID:27095570

  4. 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

  5. Modeling of [Formula: see text]-mediated calcium signaling in vascular endothelial cells induced by fluid shear stress and ATP.

    PubMed

    Li, Long-Fei; Xiang, Cheng; Qin, Kai-Rong

    2015-10-01

    The calcium signaling plays a vital role in flow-dependent vascular endothelial cell (VEC) physiology. Variations in fluid shear stress and ATP concentration in blood vessels can activate dynamic responses of cytosolic-free [Formula: see text] through various calcium channels on the plasma membrane. In this paper, a novel dynamic model has been proposed for transient receptor potential vanilloid 4 [Formula: see text]-mediated intracellular calcium dynamics in VECs induced by fluid shear stress and ATP. Our model includes [Formula: see text] signaling pathways through P2Y receptors and [Formula: see text] channels (indirect mechanism) and captures the roles of the [Formula: see text] compound channels in VEC [Formula: see text] signaling in response to fluid shear stress (direct mechanism). In particular, it takes into account that the [Formula: see text] compound channels are regulated by intracellular [Formula: see text] and [Formula: see text] concentrations. The simulation studies have demonstrated that the dynamic responses of calcium concentration produced by the proposed model correlate well with the existing experimental observations. We also conclude from the simulation studies that endogenously released ATP may play an insignificant role in the process of intracellular [Formula: see text] response to shear stress.

  6. 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.

  7. 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

  8. 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

  9. 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...

  10. 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)

  11. Nitric oxide mediates caerulein-induced suppression of locomotor activity.

    PubMed

    Volke, V; Soosaar, A; Kõks, S; Bourin, M; Männistö, P T; Vasar, E

    1996-08-01

    Caerulein, a non-selective agonist of cholecystokinin (CCK) receptors, is shown to suppress locomotor activity in rodents via stimulation of CCK(A) receptors. In the present study we examined the possible involvement of nitric oxide (NO) in caerulein-induced hypolocomotion in rats. Caerulein (10 microg/kg) markedly decreased the horizontal and vertical components of locomotor activity in rats measured in dark motility boxes. Pretreatment with a nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME), at 5 mg/kg i.p., abolished the inhibiting action of caerulein on the horizontal activity, but did not affect the reduced frequency of rearing. The other doses of L-NAME (1, 10 and 20 mg/kg) were ineffective against caerulein. As L-NAME at this dose range does not stimulate locomotor activity, it is likely that NO is involved in the motor suppressant effect of systemically administered caerulein.

  12. The descending corticocollicular pathway mediates learning-induced auditory plasticity

    PubMed Central

    Bajo, Victoria M; Nodal, Fernando R; Moore, David R; King, Andrew J

    2013-01-01

    Descending projections from sensory areas of the cerebral cortex are among the largest pathways in the brain, suggesting that they are important for subcortical processing. Although corticofugal inputs have been shown to modulate neuronal responses in the thalamus and midbrain, the behavioral importance of these changes remains unknown. In the auditory system, one of the major descending pathways is from cortical layer V pyramidal cells to the inferior colliculus in the midbrain. We examined the role of these neurons in experience-dependent recalibration of sound localization in adult ferrets by selectively killing the neurons using chromophore-targeted laser photolysis. When provided with appropriate training, animals normally relearn to localize sound accurately after altering the spatial cues available by reversibly occluding one ear. However, this ability was lost after eliminating corticocollicular neurons, whereas normal sound-localization accuracy was unaffected. The integrity of this descending pathway is therefore critical for learning-induced localization plasticity. PMID:20037578

  13. Autophagy mediates caloric restriction-induced lifespan extension in Arabidopsis.

    PubMed

    Minina, Elena A; Sanchez-Vera, Victoria; Moschou, Panagiotis N; Suarez, Maria F; Sundberg, Eva; Weih, Martin; Bozhkov, Peter V

    2013-04-01

    Caloric restriction (CR) extends lifespan in various heterotrophic organisms ranging from yeasts to mammals, but whether a similar phenomenon occurs in plants remains unknown. Plants are autotrophs and use their photosynthetic machinery to convert light energy into the chemical energy of glucose and other organic compounds. As the rate of photosynthesis is proportional to the level of photosynthetically active radiation, the CR in plants can be modeled by lowering light intensity. Here, we report that low light intensity extends the lifespan in Arabidopsis through the mechanisms triggering autophagy, the major catabolic process that recycles damaged and potentially harmful cellular material. Knockout of autophagy-related genes results in the short lifespan and suppression of the lifespan-extending effect of the CR. Our data demonstrate that the autophagy-dependent mechanism of CR-induced lifespan extension is conserved between autotrophs and heterotrophs.

  14. 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

  15. 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.

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

    PubMed

    Shin, Eun-Joo; Duong, Chu Xuan; 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

    2012-06-15

    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.

  17. 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

  18. 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

  19. 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.

  20. Allergen-induced generation of mediators in the mucosa.

    PubMed Central

    Mattoli, S

    2001-01-01

    The inhalation of antigens does not normally lead to allergic inflammation, but airway resident cells and their products may affect the outcome of antigen exposure. It is therefore important to elucidate how potential allergens interact with airway epithelial cells and other cells located within and below the epithelium. Some studies have indicated that certain antigens, particularly the major house dust mite antigen Der p1, penetrate the airway epithelium by intracellular transportation or paracellular passage, depending on their concentrations, time of exposure, and ability of the cells to inactivate them. If an antigen possesses proteolytic activity, such as Der p1, and it reaches high concentrations or the exposure is prolonged, the disruption of the tight junction can also favor the transepithelial passage of other antigens. In this way, the antigens can easily encounter the effector cells located between epithelial cells and below the basement membrane. The magnitude of this phenomenon may be more prominent in the airways of asthmatic patients, as their epithelium is more permeable to Der p1 than the epithelium of nonasthmatic patients and releases cytokines after exposure to very low concentrations of this antigen for brief periods. Epithelial cell activation may facilitate the development of allergic mucosal sensitization to Der p1 and contribute to the antigen-induced inflammatory response by affecting the migration and function of dendritic cells, mast cells, and eosinophils. Also, there might be a secondary release of interleukin-6 and endothelin-1, which can have a detrimental effect on the cardiovascular function. PMID:11544162

  1. 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 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...

  2. 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 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 6.26 - 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. Fas-induced programmed cell death is mediated by a Ras-regulated O2- synthesis.

    PubMed Central

    Gulbins, E; Brenner, B; Schlottmann, K; Welsch, J; Heinle, H; Koppenhoefer, U; Linderkamp, O; Coggeshall, K M; Lang, F

    1996-01-01

    Fas induces apoptosis in lymphocytes via a poorly defined intracellular signalling cascade. Previously, we have demonstrated the involvement and significance of a signalling cascade from the Fas receptor via sphingomyelinases and ceramide to Ras in Fas-induced apoptosis. Here we demonstrate rapid and transient synthesis of reactive oxygen intermediates (ROI) via activation of Ras after Fas. Genetic inhibition of Ras by transfection of transdominant inhibitory N17Ras blocked Fas-mediated ROI synthesis and programmed cell death. Likewise, the antioxidants N-acetyl-cysteine and N-t-butyl-phenylnitrone abolished Fas-induced cell death, pointing to an important role for Ras-triggered ROI synthesis in Fas-mediated programmed cell death. Images Figure 1 Figure 3 PMID:8943716

  12. Nicotine induces Nme2-mediated apoptosis in mouse testes.

    PubMed

    Gu, Yunqi; Xu, Wangjie; Nie, Dongsheng; Zhang, Dong; Dai, Jingbo; Zhao, Xianglong; Zhang, Meixing; Wang, Zhaoxia; Chen, Zhong; Qiao, Zhongdong

    2016-04-15

    In mouse testes, germ cell apoptosis can be caused by cigarette smoke and lead to declining quality of semen, but the exact molecular mechanisms remain unclear. To evaluate the effects of nicotine exposure on apoptosis during spermatogenesis, we first constructed a nicotine-treated mouse model and detected germ cell apoptosis activity in the testes using the TUNEL method. Then we analyzed the variation of telomere length and telomerase activity by real-time PCR and TRAP-real-time PCR, respectively. Further, we investigated a highly expressed gene, Nme2, in mouse testes after nicotine treatment from our previous results, which has close correlation with the apoptosis activity predicted by bioinformatics. We performed NME2 overexpression in Hela cells to confirm whether telomere length and telomerase activity were regulated by the Nme2 gene. Finally, we examined methylation of CpG islands in the Nme2 promoter with the Bisulfite Sequencing (BSP) method. The results showed that apoptosis had increased significantly, and then telomerase activity became weak. Further, telomere length was shortened in the germ cells among the nicotine-treated group. In Hela cells, both overexpression of the Nme2 gene and nicotine exposure can suppress the activity of telomerase activity and shorten telomere length. BSP results revealed that the Nme2 promoter appeared with low methylation in mouse testes after nicotine treatment. We assume that nicotine-induced apoptosis may be caused by telomerase activity decline, which is inhibited by the up expression of Nme2 because of its hypomethylation in mouse germ cells.

  13. HIV-infected microglia mediate cathepsin B-induced neurotoxicity.

    PubMed

    Zenón, Frances; Cantres-Rosario, Yisel; Adiga, Radhika; Gonzalez, Mariangeline; Rodriguez-Franco, Eillen; Langford, Dianne; Melendez, Loyda M

    2015-10-01

    HIV-1-infected mononuclear phagocytes release soluble factors that affect the homeostasis in tissue. HIV-1 can prompt metabolic encephalopathy with the addition of neuronal dysfunction and apoptosis. Recently, we reported that HIV-1 enhances the expression and secretion of bioactive cathepsin B in monocyte-derived macrophages, ultimately contributing to neuronal apoptosis. In this research, we asked if microglia respond to HIV infection similarly by modifying the expression, secretion, and neurotoxic potential of cathepsin B and determined the in vivo relevance of these findings. HIV-1ADA-infected human primary microglia and CHME-5 microglia cell line were assessed for expression and activity of cathepsin B, its inhibitors, cystatins B and C, and the neurotoxicity associated with these changes. Human primary neurons were exposed to supernatants from HIV-infected and uninfected microglia in the presence of cathepsin B inhibitors and apoptosis was assessed by TUNEL. Microglial expression of cathepsin B was validated in brain tissue from HIV encephalitis (HIVE) patients. HIV-infected microglia secreted significantly greater levels of cathepsin B, cystatin B, and cystatin C compared to uninfected cells. Increased apoptosis was observed in neurons exposed to supernatants from HIV-1 infected microglia at day 12 post-infection. The cathepsin B inhibitor CA-074 and cathepsin B antibody prevented neuronal apoptosis. Increased microglia-derived cathepsin B, cystatin B, and cystatin C and caspase-3+ neurons were detected in HIVE brains compared to controls. Our results suggest that HIV-1-induced cathepsin B production in microglia contributes to neuronal apoptosis and may be an important factor in neuronal death associated with HIVE.

  14. HIV-infected microglia mediate cathepsin B induced neurotoxicity

    PubMed Central

    Zenón, Frances; Cantres-Rosario, Yisel; Adiga, Radhika; Gonzalez, Mariangeline; Rodriguez-Franco, Eillen; Langford, Dianne; Melendez, Loyda M.

    2015-01-01

    BACKGROUND HIV-1-infected mononuclear phagocytes release soluble factors that affect the homeostasis in tissue. HIV-1 can prompt metabolic encephalopathy with the addition of neuronal dysfunction and apoptosis. Recently, we reported that HIV-1 enhances the expression and secretion of bioactive cathepsin B in monocyte-derived macrophages, ultimately contributing to neuronal apoptosis. In this research, we request if microglia respond to HIV infection similarly by modifying the expression, secretion, neurotoxic potential of cathepsin B and the in vivo relevance of these findings. METHODS HIV-ADA infected human primary microglia and CHME-5 were assessed for expression and activity of cathepsin B, its inhibitors, cystatins B and C, and neurotoxicity associated with these changes. Human primary neurons were exposed to supernatants from HIV-infected and uninfected microglia in the presence of cathepsin B inhibitors and apoptosis was assessed by TUNEL. Microglial expression of cathepsin B was validated in brain tissue from HIVE patients. RESULTS HIV-infected microglia secreted significantly greater levels of cathepsin B, cystatin B, and cystatin C compared to uninfected cells. Increased apoptosis was observed in neurons exposed to supernatants from HIV-1 infected microglia at days 12 post-infection. The cathepsin B inhibitor CA-074 and cathepsin B antibody prevented neuronal apoptosis. Increased microglia-derived cathepsin B, cystatin B, and cystatin C and caspase-3+ neurons were detected in HIVE brains compared to controls. CONCLUSIONS Our results suggest that HIV-1-induced cathepsin B production in microglia contributes to neuronal apoptosis and may be an important factor in neuronal death associated with HIVE. PMID:26092112

  15. 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.

  16. 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

  17. 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.

  18. Estrogen receptor subtypes selectively mediate female mouse reproductive abnormalities induced by neonatal exposure to estrogenic chemicals.

    PubMed

    Nakamura, Takeshi; Katsu, Yoshinao; Watanabe, Hajime; Iguchi, Taisen

    2008-11-20

    Perinatal exposure to estrogens such as diethylstilbestrol (DES), and to estrogenic chemicals, induces persistent anovulation caused by alteration of hypothalamic-pituitary-gonadal (HPG) axis, polyovular follicles, uterine abnormalities and persistent vaginal changes in mice. Most activities of estrogenic chemicals are mediated through estrogen receptor alpha (ERalpha) and/or ERbeta. However, little was known about the relative contribution of the individual ER subtypes in induction of abnormalities. We tested the effects of neonatal exposure to ER selective ligands and DES on female mice. Transactivation assays using mouse ERalpha and ERbeta showed that 10(-10)M DES activated both ER subtypes and that the ERalpha agonist (propyl pyrazole triol, PPT) and the ERbeta agonist (diarylpropionitrile, DPN) selectively activated their respective ERs at 10(-9)M. Neonatal female mice were injected subcutaneously with DES, PPT or DPN and the animals were examined at 13 and 15 weeks of age, respectively. Persistent estrous smears and anovulation were induced in all mice by 0.025-2.5 microg DES and 2.5-25 microg PPT, but not by DPN, suggesting that the observed anovulation was primarily mediated through ERalpha. Disorganization of uterine musculature and ovary-independent vaginal epithelial cell proliferation accompanied by persistent expression of EGF-related genes and interleukin-1-related genes were also mediated through ERalpha. In contrast, polyovular follicles were induced by neonatal treatment with both ERalpha and ERbeta ligands, suggesting that ovarian abnormalities are mediated through both ER subtypes.

  19. Programmed cell death receptor ligand 1 modulates the regulatory T cells' capacity to repress shock/sepsis-induced indirect acute lung injury by recruiting phosphatase SRC homology region 2 domain-containing phosphatase 1.

    PubMed

    Tang, Lunxian; Bai, Jianwen; Chung, Chun-Shiang; Lomas-Neira, Joanne; Chen, Yaping; Huang, Xin; Ayala, Alfred

    2015-01-01

    We recently reported that adoptively transferred (AT) exogenous CD4+ CD25+ regulatory T cells (Tregs) to wild-type (WT) mice can directly act to repress shock/sepsis-induced experimental indirect acute lung injury (iALI), and this is mediated in part by programmed cell death receptor 1 (PD-1). In this study, we further determine whether recipient mouse lacking PD-L1, one of the primary ligands for PD-1, contributes to the manipulation of the Tregs' capacity to repress lung injury. To do this, Tregs isolated from the spleen of WT mice were AT into PD-L1 mice subjected to hemorrhagic shock and subsequent to cecal ligation and puncture to induce iALI. Samples were collected for analyses 24 h after cecal ligation and puncture. We found that in PD-L1-recipient mice, AT WT-Tregs lost the ability to reverse the development of iALI seen in WT recipient mice (i.e., no reduction of lung injury indices assessed by histology and vascular leakage, failure to decrease the lung neutrophil influx [myeloperoxidase activity], or the rise in lung apoptosis [caspase 3 activity]). Also, a significant increase in interleukin 1β (IL-1β) and keratinocyte-derived chemokine, but no changes in IL-6, IL-10, and IL-17A levels in lung tissues were seen in these mice compared with iALI mice without AT of Tregs. Furthermore, we noted that the lung tissue tyrosine phosphatase Src homology region 2 domain-containing phosphatase 1 (SHP-1), but not SHP-2, was activated with the AT of Tregs in PD-L1(-/-) iALI mice. Finally, through local depletion of CD4+ T cells or CD25+ (Tregs) in the lung, prior to inducing iALI, we found that SHP-1 activation was associated with the loss of Tregs' protective effects in vivo. Collectively, our data reveal that PD-L1 is a critical modulator of Tregs' ability to suppress iALI, and this appears to involve SHP-1 activation.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Caspase-8-mediated intracellular acidification precedes mitochondrial dysfunction in somatostatin-induced apoptosis.

    PubMed

    Liu, D; Martino, G; Thangaraju, M; Sharma, M; Halwani, F; Shen, S H; Patel, Y C; Srikant, C B

    2000-03-31

    Activation of initiator and effector caspases, mitochondrial changes involving a reduction in its membrane potential and release of cytochrome c (cyt c) into the cytosol, are characteristic features of apoptosis. These changes are associated with cell acidification in some models of apoptosis. The hierarchical relationship between these events has, however, not been deciphered. We have shown that somatostatin (SST), acting via the Src homology 2 bearing tyrosine phosphatase SHP-1, exerts cytotoxic action in MCF-7 cells, and triggers cell acidification and apoptosis. We investigated the temporal sequence of apoptotic events linking caspase activation, acidification, and mitochondrial dysfunction in this system and report here that (i) SHP-1-mediated caspase-8 activation is required for SST-induced decrease in pH(i). (ii) Effector caspases are induced only when there is concomitant acidification. (iii) Decrease in pH(i) is necessary to induce reduction in mitochondrial membrane potential, cyt c release and caspase-9 activation and (iv) depletion of ATP ablates SST-induced cyt c release and caspase-9 activation, but not its ability to induce effector caspases and apoptosis. These data reveal that SHP-1-/caspase-8-mediated acidification occurs at a site other than the mitochondrion and that SST-induced apoptosis is not dependent on disruption of mitochondrial function and caspase-9 activation.

  6. 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.

  7. Different contributions of clathrin- and caveolae-mediated endocytosis of vascular endothelial cadherin to lipopolysaccharide-induced vascular hyperpermeability.

    PubMed

    Zhang, Ye; Zhang, Lianyang; Li, Yang; Sun, Shijin; Tan, Hao

    2014-01-01

    Vascular hyperpermeability induced by lipopolysaccharide (LPS) is a common pathogenic process in cases of severe trauma and sepsis. Vascular endothelial cadherin (VE-cad) is a key regulatory molecule involved in this process, although the detailed mechanism through which this molecule acts remains unclear. We assessed the role of clathrin-mediated and caveolae-mediated endocytosis of VE-cad in LPS-induced vascular hyperpermeability in the human vascular endothelial cell line CRL-2922 and determined that vascular permeability and VE-cad localization at the plasma membrane were negatively correlated after LPS treatment. Additionally, the loss of VE-cad at the plasma membrane was caused by both clathrin-mediated and caveolae-mediated endocytosis. Clathrin-mediated endocytosis was dominant early after LPS treatment, and caveolae-mediated endocytosis was dominant hours after LPS treatment. The caveolae-mediated endocytosis of VE-cad was activated through the LPS-Toll-like receptor 4 (TLR4)-Src signaling pathway. Structural changes in the actin cytoskeleton, specifically from polymerization to depolymerization, were important reasons for the switching of the VE-cad endocytosis pathway from clathrin-mediated to caveolae-mediated. Our findings suggest that clathrin-mediated and caveolae-mediated endocytosis of VE-cad contribute to LPS-induced vascular hyperpermeability, although they contribute via different mechanism. The predominant means of endocytosis depends on the time since LPS treatment.

  8. A chimerism-based approach to induce tolerance in IgE-mediated allergy.

    PubMed

    Baranyi, Ulrike; Pilat, Nina; Gattringer, Martina; Wekerle, Thomas

    2009-01-01

    Immunoglobulin-E-mediated allergy (type I allergy) is a T-helper-2-mediated disease with increasing prevalence in industrialized countries. Immunotherapy is available as causative treatment, but an effective preventive strategy is still an unmet need. Molecular chimerism is an attractive experimental approach that induces tolerance through transplantation of autologous hematopoietic stem cells that are genetically modified to express the disease-causing antigen(s). Molecular chimerism leads to permanent and robust tolerance in experimental models of autoimmune diseases and organ transplantation. Recently, proof-of-principle studies demonstrated that a type I allergic immune response can be durably tolerized by transplantation of allergen-expressing syngeneic bone marrow. We review the concept of tolerance induction through chimerism and discuss the potential of this strategy in immunoglobulin-E-mediated allergy.

  9. 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.

  10. 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

  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. LIM kinase-2 induces programmed necrotic neuronal death via dysfunction of DRP1-mediated mitochondrial fission.

    PubMed

    Kim, J-E; Ryu, H J; Kim, M J; Kang, T-C

    2014-07-01

    Although the aberrant activation of cell cycle proteins has a critical role in neuronal death, effectors or mediators of cyclin D1/cyclin-dependent kinase 4 (CDK4)-mediated death signal are still unknown. Here, we describe a previously unsuspected role of LIM kinase 2 (LIMK2) in programmed necrotic neuronal death. Downregulation of p27(Kip1) expression by Rho kinase (ROCK) activation induced cyclin D1/CDK4 expression levels in neurons vulnerable to status epilepticus (SE). Cyclin D1/CDK4 complex subsequently increased LIMK2 expression independent of caspase-3 and receptor interacting protein kinase 1 activity. In turn, upregulated LIMK2 impaired dynamic-related protein-1 (DRP1)-mediated mitochondrial fission without alterations in cofilin phosphorylation/expression and finally resulted in necrotic neuronal death. Inhibition of LIMK2 expression and rescue of DRP1 function attenuated this programmed necrotic neuronal death induced by SE. Therefore, we suggest that the ROCK-p27(Kip1)-cyclin D1/CDK4-LIMK2-DRP1-mediated programmed necrosis may be new therapeutic targets for neuronal death.

  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. 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

  15. Critical role of interleukin-17/interleukin-17 receptor axis in mediating Con A-induced hepatitis.

    PubMed

    Yan, Shu; Wang, Luman; Liu, Nan; Wang, Ying; Chu, Yiwei

    2012-04-01

    Concanavalin A (Con A)-induced hepatitis is thought to be a T-cell-mediated disease with active destruction of liver cells. Interleukin (IL)-17 is a cytokine produced principally by CD4(+) T cells. However, whether IL-17/IL-17 receptor (IL-17/IL-17R)-mediated responses are involved in T-cell-mediated Con A-induced liver injury remains unclear. In this study, we found that IL-17 expression was highly elevated in liver tissues during Con A-induced hepatitis. The increased levels of IL-17 were paralleled with the severity of liver injury reflected by Alanine aminotransaminase and histological assay as well as the secretion of tumor necrosis factor (TNF)-α and IL-6. Blockage of IL-17 significantly ameliorated Con A-induced hepatitis, while overexpression of IL-17 systemically resulted in massive hepatocyte necrosis in mice. Furthermore, overexpression of an IL-17R immunoglobulin G1 fusion protein significantly attenuated liver inflammation after acute Con A treatment. High expression of IL-17R on Kupffer cells was also observed along with the production of cytokines including TNF-α and IL-6. Inhibition of Kupffer cells by gadolinium chloride completely prevented Con A-induced liver injury and cytokine release. Finally, IL-17-expressing CD4(+) T and natural killer T cells were greatly increased in Con A-injected mice compared with that in controls. Overall, our results indicate that IL-17R signaling is critically involved in the pathogenesis in Con A-induced hepatitis, and blockade of IL-17/IL-17R signaling pathway may represent a novel therapeutic intervention in human autoimmune-related hepatitis.

  16. 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.

  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. Are Basophils Important Mediators for Helminth-Induced Th2 Immune Responses? A Debate

    PubMed Central

    Leon-Cabrera, Sonia; Flisser, Ana

    2012-01-01

    Helminth parasites induce Th2 immune responses. Immunological mechanisms leading to Th2 induction are mainly dependent on IL-4. However, early source of IL-4 has not been precisely identified. Noticeably, basophils seem to be important mediators for inducing and maintaining the Th2 response probably because they secrete IL-4 and exert functions similar to APCs. Nevertheless, recent experimental evidence points that DCs could be also significant participants during this process. The involvement of basophils during memory responses is also discussed. PMID:22500083

  19. Simvastatin may induce insulin resistance through a novel fatty acid mediated cholesterol independent mechanism

    PubMed Central

    Kain, Vasundhara; Kapadia, Bandish; Misra, Parimal; Saxena, Uday

    2015-01-01

    Statins are a class of oral drugs that are widely used for treatment of hypercholesterolemia. Recent clinical data suggest that chronic use of these drugs increases the frequency of new onset diabetes. Studies to define the risks of statin-induced diabetes and its underlying mechanisms are clearly necessary. We explored the possible mechanism of statin induced insulin resistance using a well-established cell based model and simvastatin as a prototype statin. Our data show that simvastatin induces insulin resistance in a cholesterol biosynthesis inhibition independent fashion but does so by a fatty acid mediated effect on insulin signaling pathway. These data may help design strategies for prevention of statin induced insulin resistance and diabetes in patients with hypercholesterolemia. PMID:26345110

  20. 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

  1. 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

  2. Tristetraprolin mediates anti-inflammatory effects of carbon monoxide on lipopolysaccharide-induced acute lung injury.

    PubMed

    Joe, Yeonsoo; Kim, Seul-Ki; Chen, Yingqing; Yang, Jung Wook; Lee, Jeong-Hee; Cho, Gyeong Jae; Park, Jeong Woo; Chung, Hun Taeg

    2015-11-01

    Low-dose inhaled carbon monoxide is reported to suppress inflammatory responses and exhibit a therapeutic effect in models of lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, the precise mechanism by which carbon monoxide confers protection against ALI is not clear. Tristetraprolin (TTP; official name ZFP36) exerts anti-inflammatory effects by enhancing decay of proinflammatory cytokine mRNAs. With the use of TTP knockout mice, we demonstrate here that the protection by carbon monoxide against LPS-induced ALI is mediated by TTP. Inhalation of carbon monoxide substantially increased the pulmonary expression of TTP. carbon monoxide markedly enhanced the decay of mRNA-encoding inflammatory cytokines, blocked the expression of inflammatory cytokines, and decreased tissue damage in LPS-treated lung tissue. Moreover, knockout of TTP abrogated the anti-inflammatory and tissue-protective effects of carbon monoxide in LPS-induced ALI. These results suggest that carbon monoxide-induced TTP mediates the protective effect of carbon monoxide against LPS-induced ALI by enhancing the decay of mRNA encoding proinflammatory cytokines.

  3. Troxerutin protects the mouse liver against oxidative stress-mediated injury induced by D-galactose.

    PubMed

    Zhang, Zi-feng; Fan, Shao-hua; Zheng, Yuan-lin; Lu, Jun; Wu, Dong-mei; Shan, Qun; Hu, Bin

    2009-09-01

    Troxerutin, a trihydroxyethylated derivative of rutin, has been well-demonstrated to exert hepatoprotective properties. In the present study, we attempted to explore whether the antioxidant and anti-inflammatory mechanisms were involved in troxerutin-mediated protection from D-gal-induced liver injury. The effects of troxerutin on liver lipid peroxidation, antioxidant enzymatic activities, and the expression of inflammatory mediator were investigated in D-gal-treated mice. The results showed that troxerutin largely attenuated the D-gal-induced TBARS content increase and also markedly renewed the activities of Cu, Zn-SOD, CAT, and GPx in the livers of D-gal-treated mice. Furthermore, troxerutin inhibited the upregulation of the expression of NF-kappaB p65, iNOS, and COX-2 induced by D-gal. D-Gal-induced tissue architecture changes and serum ALT and AST increases were effectively suppressed by troxerutin. In conclusion, these results suggested that troxerutin could protect the mouse liver from D-gal-induced injury by attenuating lipid peroxidation, renewing the activities of antioxidant enzymes and suppressing inflammatory response. This study provided novel insights into the mechanisms of troxerutin in the protection of the liver.

  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.

  5. 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.

  6. Contribution of radiation-induced, nitric oxide-mediated bystander effect to radiation-induced adaptive response.

    NASA Astrophysics Data System (ADS)

    Matsumoto, H.; Ohnishi, T.

    There has been a recent upsurge of interest in radiation-induced adaptive response and bystander effect which are specific modes in stress response to low-dose low-dose rate radiation Recently we found that the accumulation of inducible nitric oxide NO synthase iNOS in wt p53 cells was induced by chronic irradiation with gamma rays followed by acute irradiation with X-rays but not by each one resulting in an increase in nitrite concentrations of medium It is suggested that the accumulation of iNOS may be due to the depression of acute irradiation-induced p53 functions by pre-chronic irradiation In addition we found that the radiosensitivity of wt p53 cells against acute irradiation with X-rays was reduced after chronic irradiation with gamma rays This reduction of radiosensitivity of wt p53 cells was nearly completely suppressed by the addition of NO scavenger carboxy-PTIO to the medium This reduction of radiosensitivity of wt p53 cells is just radiation-induced adaptive response suggesting that NO-mediated bystander effect may considerably contribute to adaptive response induced by radiation

  7. PreBotzinger complex neurokinin-1 receptor-expressing neurons mediate opioid-induced respiratory depression.

    PubMed

    Montandon, Gaspard; Qin, Wuxuan; Liu, Hattie; Ren, Jun; Greer, John J; Horner, Richard L

    2011-01-26

    The analgesic properties of the opium poppy Papever somniferum were first mentioned by Hippocrates around 400 BC, and opioid analgesics remain the mainstay of pain management today. These drugs can cause the serious side-effect of respiratory depression that can be lethal with overdose, however the critical brain sites and neurochemical identity of the neurons mediating this depression are unknown. By locally manipulating neurotransmission in the adult rat, we identify the critical site of the medulla, the preBötzinger complex, that mediates opioid-induced respiratory depression in vivo. Here we show that opioids at the preBötzinger complex cause respiratory depression or fatal apnea, with anesthesia and deep-sleep being particularly vulnerable states for opioid-induced respiratory depression. Importantly, we establish that the preBötzinger complex is fully responsible for respiratory rate suppression following systemic administration of opioid analgesics. The site in the medulla most sensitive to opioids corresponds to a region expressing neurokinin-1 receptors, and we show in rhythmically active brainstem section in vitro that neurokinin-1 receptor-expressing preBötzinger complex neurons are selectively inhibited by opioids. In summary, neurokinin-1 receptor-expressing preBötzinger complex neurons constitute the critical site mediating opioid-induced respiratory rate depression, and the key therapeutic target for its prevention or reversal.

  8. Glycogen synthase kinase-3 facilitates con a-induced IFN-γ-- mediated immune hepatic injury.

    PubMed

    Tsai, Cheng-Chieh; Huang, Wei-Ching; Chen, Chia-Ling; Hsieh, Chia-Yuan; Lin, Yee-Shin; Chen, Shun-Hua; Yang, Kao-Chi; Lin, Chiou-Feng

    2011-10-01

    Immune hepatic injury induced by Con A results primarily from IFN-γ-mediated inflammation, followed by hepatic cell death. Glycogen synthase kinase (GSK)-3, which acts proapoptotically and is proinflammatory, is also important for facilitating IFN-γ signaling. We hypothesized a pathogenic role for GSK-3 in Con A hepatic injury. Con A stimulation caused GSK-3 activation in the livers of C57BL/6 mice. Inhibiting GSK-3 reduced Con A hepatic injury, including hepatic necrosis and apoptosis, inflammation, infiltration of T cells and granulocytes, and deregulated expression of adhesion molecule CD54. Con A induced hepatic injury in an IFN-γ receptor 1-dependent manner. Con A/IFN-γ induced activation and expression of STAT1 in a GSK-3-dependent manner. GSK-3 facilitated IFN-γ-induced inducible NO synthase, but had limited effects on CD95 upregulation and CD95-mediated hepatocyte apoptosis in vitro. Notably, inhibiting GSK-3 decreased Con A-induced IFN-γ production in both wild-type and IFN-γ receptor 1-deficient C57BL/6 mice. In Con A-activated NKT cells, GSK-3 was also activated and was required for nuclear translocation of T-box transcription factor Tbx21, a transcription factor of IFN-γ, but it was not required for CD95 ligand expression or activation-induced cell death. These results demonstrate the dual and indispensable role of GSK-3 in Con A hepatic injury by facilitating IFN-γ-induced hepatopathy.

  9. 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

  10. 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.

  11. p38alpha and p38gamma mediate oncogenic ras-induced senescence through differential mechanisms.

    PubMed

    Kwong, Jinny; Hong, Lixin; Liao, Rong; Deng, Qingdong; Han, Jiahuai; Sun, Peiqing

    2009-04-24

    Oncogene-induced senescence is a tumor-suppressive defense mechanism triggered upon activation of certain oncogenes in normal cells. Recently, the senescence response to oncogene activation has been shown to act as a bona fide barrier to cancer development in vivo. Multiple previous studies have implicated the importance of the p38 MAPK pathway in oncogene-induced senescence. However, the contribution of each of the four p38 isoforms (encoded by different genes) to senescence induction is unclear. In the current study, we demonstrated that p38alpha and p38gamma, but not p38beta, play an essential role in oncogenic ras-induced senescence. Both p38alpha and p38gamma are expressed in primary human fibroblasts and are activated upon transduction of oncogenic ras. Small hairpin RNA-mediated silencing of p38alpha or p38gamma expression abrogated ras-induced senescence, whereas constitutive activation of p38alpha and p38gamma caused premature senescence. Furthermore, upon activation by oncogenic ras, p38gamma stimulated the transcriptional activity of p53 by phosphorylating p53 at Ser(33), suggesting that the ability of p38gamma to mediate senescence is at least partly achieved through p53. However, p38alpha contributed to ras-inducted senescence via a p53-indepdendent mechanism in cells by mediating ras-induced expression of p16(INK4A), another key senescence effector. These findings have identified p38alpha and p38gamma as essential components of the signaling pathway that regulates the tumor-suppressing senescence response, providing insights into the molecular mechanisms underlying the differential involvement of the p38 isoforms in senescence induction.

  12. 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

  13. 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.

  14. Endothelial contraction induced by histamine-type mediators: an electron microscopic study.

    PubMed

    Majno, G; Shea, S M; Leventhal, M

    1969-09-01

    Previous work has shown that endogenous chemical mediators, of which histamine is the prototype, increase the permeability of blood vessels by causing gaps to appear between endothelial cells. In the present paper, morphologic and statistical evidence is presented, to suggest that endothelial cells contract under the influence of mediators, and that this contraction causes the formation of intercellular gaps. Histamine, serotonin, and bradykinin were injected subcutaneously into the scrotum of the rat, and the vessels of the underlying cremaster muscle were examined by electron microscopy. To eliminate the vascular collapse induced by routine fixation, in one series of animals (including controls) the root of the cremaster was constricted for 2-4 min prior to sacrifice, and the tissues were fixed under conditions of mild venous congestion. Electron micrographs were taken of 599 nuclei from the endothelium of small blood vessels representing the various experimental situations. Nuclear deformations were classified into four types of increasing tightness (notches, foldsl closing folds, and pinches. In the latter the apposed surfaces of the nuclear membrane are in contact). It was found that: (1) venous congestion tends to straighten the nuclei in al groups; (2) mediators cause a highly significant increase in the number of pinches (P < 0.001), also if the vessels are distended by venous congestion; (3) fixation without venous congestion causes vascular collapse. The degree of endothelial recoil, as measured by nuclear pinches, is very different from that caused by mediators (P < 0.001). (4) Pinched nuclei are more frequent in leaking vessels, and in cells adjacent to gaps (P < 0.001); (5) mediators also induce, in the endothelium, cytoplasmic changes suggestive of contraction, and similar to those of contracted smooth muscle; (6) there is no evidence of pericyte contraction under the conditions tested. Occasional pericytes appeared to receive fine nerve endings

  15. Effects of intravenous immunoglobulins on T-cell mediated, concanavalin A-induced hepatitis in mice.

    PubMed

    Shirin, H; Bruck, R; Aeed, H; Hershkoviz, R; Lider, O; Kenet, G; Avni, Y; Halpern, Z

    1997-12-01

    Concanavalin A (ConA) activates T lymphocytes and causes T-cell mediated hepatic injury in mice. The intravenous administration of human immunoglobulins has beneficial effects in T-cell mediated diseases such as experimental autoimmune encephalomyelitis and adjuvant arthritis. In the present study, we examined the effects of intravenous immunoglobulins in a mouse model of T-cell mediated, acute liver injury induced by concanavalin A. Balb/c mice were inoculated with 12 mg/kg concanavalin A with or without intravenous immunoglobulins at doses of 0.4, 0.6, 0.8 g/kg body wt. The serum levels of liver enzymes, tumor necrosis factor-alpha, interferon-gamma and interleukin-6 were assayed 2, 6 and 24 h after concanavalin A administration. Intravenous immunoglobulins did not prevent concanavalin A-induced hepatitis, as manifested by elevation of serum aminotransferases and histopathological evaluation. The serum levels of tumor necrosis factor-alpha in mice pretreated with immunoglobulins, measured 2 h after ConA treatment were reduced, while interferon-gamma levels measured 6 h after ConA inoculation were 5-fold higher than control levels. There was no effect of intravenous immunoglobulins on the release of interleukin 6. In conclusion, these results indicate that intravenous immunoglobulin is not effective in preventing T-cell mediated concanavalin A-induced hepatitis. The increased secretion of interferon-gamma and the incomplete suppression of tumor necrosis factor-alpha release may explain the lack of efficacy of intravenous immunoglobulin in this experimental model. PMID:9455732

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. Matrine inhibits proliferation and induces apoptosis via BID-mediated mitochondrial pathway in esophageal cancer cells.

    PubMed

    Wang, Qiao; Du, Haoxin; Geng, Guojun; Zhou, Huan; Xu, Minying; Cao, Hanwei; Zhang, Bing; Song, Gang; Hu, Tianhui

    2014-05-01

    Matrine, as a member of Sophora family, is an alkaloid found in plants, and produces plethora pharmacological effects, including anti-cancer effects. However, the mechanism involved remains largely unknown. This study is conducted to investigate the anti-cancer mechanisms of matrine in human esophageal cancer in vitro and in vivo. In human esophageal cancer cell Eca-109, matrine significantly decreased the cell viability in a dose-dependent manner, and induced apoptosis as well as cell cycle arrest in G0/G1 phase by up-regulation of P53 and P21. The expression of several apoptosis-related proteins in cells and tumor tissues were evaluated by Western blot analysis. We found that matrine induced cell apoptosis by down-regulation of the ratio of BCL-2/BID and increasing activation of caspase-9. Further studies indicated that matrine induced apoptosis of Eca-109 was through the mitochondria-mediated internal pathway, but not by death receptor-mediated extrinsic apoptotic pathway, which was confirmed by the fact that Bid translocated from the nucleus to mitochondria during the process of the apoptosis induced by matrine. In vivo study found that matrine effectively inhibited the tumor formation of Eca-109 cells in nude mice. Our study suggests that matrine could serve as a potential novel agent from natural products to treat esophageal cancer.

  2. 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

  3. Nox2 mediates skeletal muscle insulin resistance induced by a high fat diet.

    PubMed

    Souto Padron de Figueiredo, Alvaro; Salmon, Adam B; Bruno, Francesca; Jimenez, Fabio; Martinez, Herman G; Halade, Ganesh V; Ahuja, Seema S; Clark, Robert A; DeFronzo, Ralph A; Abboud, Hanna E; El Jamali, Amina

    2015-05-22

    Inflammation and oxidative stress through the production of reactive oxygen species (ROS) are consistently associated with metabolic syndrome/type 2 diabetes. Although the role of Nox2, a major ROS-generating enzyme, is well described in host defense and inflammation, little is known about its potential role in insulin resistance in skeletal muscle. Insulin resistance induced by a high fat diet was mitigated in Nox2-null mice compared with wild-type mice after 3 or 9 months on the diet. High fat feeding increased Nox2 expression, superoxide production, and impaired insulin signaling in skeletal muscle tissue of wild-type mice but not in Nox2-null mice. Exposure of C2C12 cultured myotubes to either high glucose concentration, palmitate, or H2O2 decreases insulin-induced Akt phosphorylation and glucose uptake. Pretreatment with catalase abrogated these effects, indicating a key role for H2O2 in mediating insulin resistance. Down-regulation of Nox2 in C2C12 cells by shRNA prevented insulin resistance induced by high glucose or palmitate but not H2O2. These data indicate that increased production of ROS in insulin resistance induced by high glucose in skeletal muscle cells is a consequence of Nox2 activation. This is the first report to show that Nox2 is a key mediator of insulin resistance in skeletal muscle.

  4. 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

    2015-10-26

    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.

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

    PubMed Central

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

    2011-01-01

    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

  6. 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

  7. 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.

  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. ZINC-mediated gene expression offers protection against H{sub 2}O{sub 2}-induced cytotoxicity

    SciTech Connect

    Chung, M.J.; Walker, Paul A.; Brown, Ray W.; Hogstrand, Christer . E-mail: christer.hogstrand@kcl.ac.uk

    2005-06-15

    The ability of zinc to mobilize defense against reactive oxygen species (ROS) and H{sub 2}O{sub 2}-induced apoptosis was studied using a primary culture of rainbow trout gill cells. Gill cells were pretreated for 24 h with 100 {mu}M ZnSO{sub 4} followed by 24-h exposure to 100 or 200 {mu}M H{sub 2}O{sub 2}, or were subjected to 100 {mu}M ZnSO{sub 4} together with 100 or 200 {mu}M H{sub 2}O{sub 2}. Metallothionein-A (MTA) and metallothionein-B (MTB) mRNA levels were increased after treatment with zinc or H{sub 2}O{sub 2}, separately or in combination. Similarly, mRNA for glutathione S-transferase (GST) and glucose 6-phosphate dehydrogenase (G6PD) were increased in response to either zinc or H{sub 2}O{sub 2}, or after sequential treatments with zinc followed by H{sub 2}O{sub 2}. The stimulatory effects of zinc or H{sub 2}O{sub 2} on MTA, MTB, GST, and G6PD mRNA levels could be blocked by addition of the membrane permeable zinc chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), suggesting that H{sub 2}O{sub 2}-induced upregulation of these genes is zinc-dependent. Pretreatment with zinc protected the cells from subsequent cell damage and apoptosis, as assessed by lactate dehydrogenase leakage, mitochondrial dehydrogenase activity (MTT assay), caspase-3 activity, and DNA fragmentation. In contrast, when gill cells were coincubated with zinc and H{sub 2}O{sub 2} at the same time, H{sub 2}O{sub 2} toxicity was higher than after treatment with H{sub 2}O{sub 2} alone. It is concluded that zinc had a direct pro-oxidant effect when administered together with H{sub 2}O{sub 2}, but that pretreatment of zinc inhibited cytotoxicity and apoptosis through an indirect antioxidant action. We propose that the antioxidant action is manifested through zinc-dependent expression of several genes encoding antioxidant proteins (e.g., MTA, MTB, G6PD, and GST). Furthermore, the apparent zinc-dependency of H{sub 2}O{sub 2}-induced expression of antioxidant genes suggests

  11. Lysosome-membrane fusion mediated superoxide production in hyperglycaemia-induced endothelial dysfunction.

    PubMed

    Bao, Jun-Xiang; Chang, Hui; Lv, Yong-Gang; Yu, Jin-Wen; Bai, Yun-Gang; Liu, Huan; Cai, Yue; Wang, Ling; Ma, Jin; Chang, Yao-Ming

    2012-01-01

    Lysosomal exocytosis and fusion to cellular membrane is critical in the oxidative stress formation of endothelium under apoptotic stimulus. We investigated the role therein of it in hyperglycaemia-induced endothelial dysfunction. The lysosome-membrane fusion was shown by the expression of lamp1, the lysosomal membrane marker, on cellular membrane and the transportation of lysosomal symbolic enzymes into cultural medium. We also examined the ceramide production, lipid rafts (LRs) clustering, colocalization of gp91(phox), a NADPH oxidase subunit (NOX) to LRs clusters, superoxide (O₂·⁻) formation and nitric oxide (NO) content in human umbilical vein endothelial cells (HUVEC) and the endothelium-dependent NO-mediated vasodilation in isolated rat aorta. As compared to normal glucose (5.6 mmol/l, Ctrl) incubation, high glucose (22 mmol/l, HG) exposure facilitated the lysosome-membrane fusion in HUVEC shown by significantly increased quantity of lamp1 protein on cellular membrane and enhanced activity of lysosomal symbolized enzymes in cultural medium. HG incubation also elicited ceramide generation, LRs clustering and gp91(phox) colocalization to LRs clusters which were proved to mediate the HG induced O₂·⁻ formation and NO depletion in HUVEC. Functionally, the endothelium-dependent NO-mediated vasodilation in aorta was blunted substantially after HG incubation. Moreover, the HG-induced effect including ceramide production, LRs clustering, gp91(phox) colocalization to LRs clusters, O₂·⁻ formation and endothelial dysfunction could be blocked significantly by the inhibition of lysosome-membrane fusion. We propose that hyperglycaemia-induced endothelial impairment is closely related to the lysosome-membrane fusion and the following LRs clustering, LRs-NOX platforms formation and O₂·⁻ production. PMID:22253932

  12. Tenascin-C induces inflammatory mediators and matrix degradation in osteoarthritic cartilage

    PubMed Central

    2011-01-01

    Background Tenascin-C (TN-C) is an extracellular matrix glycoprotein that is involved in tissue injury and repair processes. We analyzed TN-C expression in normal and osteoarthritic (OA) human cartilage, and evaluated its capacity to induce inflammatory and catabolic mediators in chondrocytes in vitro. The effect of TN-C on proteoglycan loss from articular cartilage in culture was also assessed. Methods TN-C in culture media, cartilage extracts, and synovial fluid of human and animal joints was quantified using a sandwich ELISA and/or analyzed by Western immunoblotting. mRNA expression of TN-C and aggrecanases were analyzed by Taqman assays. Human and bovine primary chondrocytes and/or explant culture systems were utilized to study TN-C induced inflammatory or catabolic mediators and proteoglycan loss. Total proteoglycan and aggrecanase -generated ARG-aggrecan fragments were quantified in human and rat synovial fluids by ELISA. Results TN-C protein and mRNA expression were significantly upregulated in OA cartilage with a concomitant elevation of TN-C levels in the synovial fluid of OA patients. IL-1 enhanced TN-C expression in articular cartilage. Addition of TN-C induced IL-6, PGE2, and nitrate release and upregulated ADAMTS4 mRNA in cultured primary human and bovine chondrocytes. TN-C treatment resulted in an increased loss of proteoglycan from cartilage explants in culture. A correlation was observed between TN-C and aggrecanase generated ARG-aggrecan fragment levels in the synovial fluid of human OA joints and in the lavage of rat joints that underwent surgical induction of OA. Conclusions TN-C expression in the knee cartilage and TN-C levels measured in the synovial fluid are significantly enhanced in OA patients. Our findings suggest that the elevated levels of TN-C could induce inflammatory mediators and promote matrix degradation in OA joints. PMID:21762512

  13. Reactive oxygen species mediated apoptosis of esophageal cancer cells induced by marine triprenyl toluquinones and toluhydroquinones.

    PubMed

    Whibley, Catherine E; McPhail, Kerry L; Keyzers, Robert A; Maritz, Michelle F; Leaner, Virna D; Birrer, Michael J; Davies-Coleman, Michael T; Hendricks, Denver T

    2007-09-01

    Marine invertebrates, algae, and microorganisms are prolific producers of novel secondary metabolites. Some of these secondary metabolites have the potential to be developed as chemotherapeutic agents for the treatment of a wide variety of diseases, including cancer. We describe here the mechanism leading to apoptosis of esophageal cancer cell lines in the presence of triprenylated toluquinones and toluhydroquinones originally isolated from the Arminacean nudibranch Leminda millecra. Triprenylated toluquinone-induced and toluhydroquinone-induced cell death is mediated via apoptosis after a cell cycle block. Molecular events include production of reactive oxygen species (ROS), followed by induction and activation of c-Jun (AP1) via c-Jun-NH2-kinase-mediated and extracellular signal-regulated kinase-mediated pathways. Partial resistance to these compounds could be conferred by the ROS scavengers Trolox and butylated hydroxyanisol, a c-Jun-NH2-kinase inhibitor, and inhibition of c-Jun with a dominant negative mutant (TAM67). Interestingly, the levels of ROS produced varied between compounds, but was proportional to the ability of each compound to kill cells. Because cancer cells are often more susceptible to ROS, these compounds present a plausible lead for new antiesophageal cancer treatments and show the potential of the South African marine environment to provide new chemical entities with potential clinical significance. PMID:17876050

  14. MicroRNA-mediated gene silencing modulates the UV-induced DNA-damage response

    PubMed Central

    Pothof, Joris; Verkaik, Nicole S; van IJcken, Wilfred; Wiemer, Erik A C; Ta, Van T B; van der Horst, Gijsbertus T J; Jaspers, Nicolaas G J; van Gent, Dik C; Hoeijmakers, Jan H J; Persengiev, Stephan P

    2009-01-01

    DNA damage provokes DNA repair, cell-cycle regulation and apoptosis. This DNA-damage response encompasses gene-expression regulation at the transcriptional and post-translational levels. We show that cellular responses to UV-induced DNA damage are also regulated at the post-transcriptional level by microRNAs. Survival and checkpoint response after UV damage was severely reduced on microRNA-mediated gene-silencing inhibition by knocking down essential components of the microRNA-processing pathway (Dicer and Ago2). UV damage triggered a cell-cycle-dependent relocalization of Ago2 into stress granules and various microRNA-expression changes. Ago2 relocalization required CDK activity, but was independent of ATM/ATR checkpoint signalling, whereas UV-responsive microRNA expression was only partially ATM/ATR independent. Both microRNA-expression changes and stress-granule formation were most pronounced within the first hours after genotoxic stress, suggesting that microRNA-mediated gene regulation operates earlier than most transcriptional responses. The functionality of the microRNA response is illustrated by the UV-inducible miR-16 that downregulates checkpoint-gene CDC25a and regulates cell proliferation. We conclude that microRNA-mediated gene regulation adds a new dimension to the DNA-damage response. PMID:19536137

  15. 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.

  16. Evidence for fatty acids mediating CL 316,243-induced reductions in blood glucose in mice.

    PubMed

    MacPherson, Rebecca E K; Castellani, Laura; Beaudoin, Marie-Soleil; Wright, David C

    2014-10-01

    CL 316,243, a β3-adrenergic agonist, was developed as an antiobesity and diabetes drug and causes rapid decreases in blood glucose levels in mice. The mechanisms mediating this effect have not been fully elucidated; thus, the purpose of the current study was to examine the role of fatty acids and interleukin-6, reputed mediators of insulin secretion, in this process. To address this question, we used physiological and pharmacological approaches in combination with knockout mouse models. CL 316,243 treatment in male C57BL6 mice increased plasma fatty acids, glycerol, interleukin-6, and insulin and reduced blood glucose concentrations 2 h following injections. The ability of CL 316,243 to increase insulin and fatty acids and reduce glucose was preserved in interleukin-6-deficient mice. CL 316,243-induced drops in blood glucose occurred in parallel with increases in circulating fatty acids but prior to increases in plasma interleukin-6. CL 316,243-mediated increases in plasma insulin levels and reductions in blood glucose were attenuated when mice were pretreated with the lipase inhibitor nicotinic acid or in whole body adipose tissue triglyceride lipase knockout mice. Collectively, our findings demonstrate an important role for fatty acids in mediating the effects of CL 316,243 in mice. Not only do our results provide new insight into the mechanisms of action of CL 316,243, but they also hint at an unappreciated aspect of adipose tissue -pancreas cross-talk. PMID:25096179

  17. 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

  18. T cell tolerance induced by histone deacetylase inhibitor is mediated by P21cip1.

    PubMed

    Gilbert, Kathleen M; Boger, Susan R; Price, Peter; Fifer, E Kim

    2005-01-01

    MEB [n-butyrate 2-(4-morpholinyl) ethyl butyrate hydrochloride], a histone deacetylase inhibitor and G1 blocker, has been shown to induce unresponsiveness in antigen-activated Th1 cells. MEB was tested for here for its ability to inactivate naive alloantigen-specific T cells from DBA/2 and C57BL/10 mice. Since T cells from these two strains of mice have been shown to differ in their cell cycle regulation, it we hoped that this comparison would provide information concerning the role of cycle regulatory proteins in mediating MEB-induced T cell unresponsiveness. MEB inhibited proliferation in a one-way mixed lymphocyte reaction (MLR) in which spleen cells from DBA/2 mice (H-2d) or C57BL/10 mice (H-2b) were stimulated with spleen cells from C57BL/10 or DBA/2 mice, respectively. C57BL/10 responder T cells isolated from the MEB-treated primary MLR remained unresponsive to alloantigen following restimulation in a secondary MLR that did not contain MEB. T cells from DBA/2 mice were less sensitive to MEB-induced unresponsiveness and required a longer exposure or pretreatment with IL-2 to become tolerant. In all cases responsiveness to MEB-induced tolerance in the alloantigen-stimulated T cells corresponded with the levels of the cyclin-dependent kinase inhibitor p21cip1. Additional experiments showed that T cells from p21cip1-deficient mice, unlike T cells from p21cip1 wild-type littermates, were resistant to MEB-induced tolerance. These results underscore the role of p21cip1 in mediating T cell tolerance induced by the histone deacetylase inhibitor MEB.

  19. Brucella abortus Induces the Secretion of Proinflammatory Mediators from Glial Cells Leading to Astrocyte Apoptosis

    PubMed Central

    García Samartino, Clara; Delpino, M. Victoria; Pott Godoy, Clara; Di Genaro, María Silvia; Pasquevich, Karina A.; Zwerdling, Astrid; Barrionuevo, Paula; Mathieu, Patricia; Cassataro, Juliana; Pitossi, Fernando; Giambartolomei, Guillermo H.

    2010-01-01

    Central nervous system (CNS) invasion by bacteria of the genus Brucella results in an inflammatory disorder called neurobrucellosis. In this study we present in vivo and in vitro evidence that B. abortus and its lipoproteins activate the innate immunity of the CNS, eliciting an inflammatory response that leads to astrogliosis, a characteristic feature of neurobrucellosis. Intracranial injection of heat-killed B. abortus (HKBA) or outer membrane protein 19 (Omp19), a B. abortus lipoprotein model, induced astrogliosis in mouse striatum. Moreover, infection of astrocytes and microglia with B. abortus induced the secretion of interleukin (IL)−6, IL-1β, tumor necrosis factor (TNF)-α, macrophage chemoattractant protein−1, and KC (CXCL1). HKBA also induced these inflammatory mediators, suggesting the involvement of a structural component of the bacterium. Accordingly, Omp19 induced the same cytokine and chemokine secretion pattern. B. abortus infection induced astrocyte, but not microglia, apoptosis. Indeed, HKBA and Omp19 elicited not only astrocyte apoptosis but also proliferation, two features observed during astrogliosis. Apoptosis induced by HKBA and L-Omp19 was completely suppressed in cells of TNF receptor p55−/− mice or when the general caspase inhibitor Z-VAD-FMK was added to cultures. Hence, TNF-α signaling via TNF receptor (TNFR) 1 through the coupling of caspases determines apoptosis. Our results provide proof of the principle that Brucella lipoproteins could be key virulence factors in neurobrucellosis and that astrogliosis might contribute to neurobrucellosis pathogenesis. PMID:20093491

  20. Etoposide induced cytotoxicity mediated by ROS and ERK in human kidney proximal tubule cells

    PubMed Central

    Shin, Hyeon-Jun; Kwon, Hyuk-Kwon; Lee, Jae-Hyeok; Anwar, Muhammad Ayaz; Choi, Sangdun

    2016-01-01

    Etoposide (ETO) is a commonly used chemotherapeutic drug that inhibits topoisomerase II activity, thereby leading to genotoxicity and cytotoxicity. However, ETO has limited application due to its side effects on normal organs, especially the kidney. Here, we report the mechanism of ETO-induced cytotoxicity progression in human kidney proximal tubule (HK-2) cells. Our results show that ETO perpetuates DNA damage, activates mitogen-activated protein kinase (MAPK), and triggers morphological changes, such as cell and nuclear swelling. When NAC, a well-known reactive oxygen species (ROS) scavenger, is co-treated with ETO, it inhibits an ETO-induced increase in mitochondrial mass, mitochondrial DNA (ND1 and ND4) copy number, intracellular ATP level, and mitochondrial biogenesis activators (TFAM, PGC-1α and PGC-1β). Moreover, co-treatment with ETO and NAC inhibits ETO-induced necrosis and cell swelling, but not apoptosis. Studies using MAPK inhibitors reveal that inhibition of extracellular signal regulated kinase (ERK) protects ETO-induced cytotoxicity by inhibiting DNA damage and caspase 3/7 activity. Eventually, ERK inhibitor treated cells are protected from ETO-induced nuclear envelope (NE) rupture and DNA leakage through inhibition of caspase activity. Taken together, these data suggest that ETO mediates cytotoxicity in HK-2 cells through ROS and ERK pathways, which highlight the preventive avenues in ETO-induced cytotoxicity in kidney. PMID:27666530

  1. UV-B radiation induces macrophage migration inhibitory factor-mediated melanogenesis through activation of protease-activated receptor-2 and stem cell factor in keratinocytes.

    PubMed

    Enomoto, Akiko; Yoshihisa, Yoko; Yamakoshi, Takako; Ur Rehman, Mati; Norisugi, Osamu; Hara, Hiroshi; Matsunaga, Kenji; Makino, Teruhiko; Nishihira, Jun; Shimizu, Tadamichi

    2011-02-01

    UV radiation indirectly regulates melanogenesis in melanocytes through a paracrine regulatory mechanism involving keratinocytes. Protease-activated receptor (PAR)-2 activation induces melanosome transfer by increasing phagocytosis of melanosomes by keratinocytes. This study demonstrated that macrophage migration inhibitory factor (MIF) stimulated PAR-2 expression in human keratinocytes. In addition, we showed that MIF stimulated stem cell factor (SCF) release in keratinocytes; however, MIF had no effect on the release of endothelin-1 or prostaglandin E2 in keratinocytes. In addition, MIF had no direct effect on melanin and tyrosinase synthesis in cultured human melanocytes. The effect of MIF on melanogenesis was also examined using a three-dimensional reconstituted human epidermal culture model, which is a novel, commercially available, cultured human epidermis containing functional melanocytes. Migration inhibitory factor induced an increase in melanin content in the epidermis after a 9-day culture period. Moreover, melanin synthesis induced by UV-B stimulation was significantly down-regulated by anti-MIF antibody treatment. An in vivo study showed that the back skin of MIF transgenic mice had a higher melanin content than that of wild-type mice after 12 weeks of UV-B exposure. Therefore, MIF-mediated melanogenesis occurs mainly through the activation of PAR-2 and SCF expression in keratinocytes after exposure to UV-B radiation.

  2. 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.

  3. 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

  4. 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

  5. Alpha-adrenergic receptors mediate imipramine/alarm substance-induced reaction in rats.

    PubMed

    Abel, E L

    1994-08-01

    The mechanism of adverse imipramine-induced reactions (jitteriness, convulsions) was investigated by precipitating such reactions in rats with three injections (IP) of imipramine (5-40 mg/kg) at 24, 5, and 1 h before testing, and comparing their occurrence with comparable treatments using specific noradrenergic and serotonergic reuptake inhibitors [nortriptyline (10 or 30 mg/kg, IP), citalopram (0.5-5.0 mg/kg, IP)]. This initial study indicated that these reactions were mediated by imipramine's noradrenergic effects. Subsequent combinations of imipramine and an alpha 2 agonist (clonidine, 5 mg/kg) and antagonist (yohimbine, 2 mg/kg), and a beta-adrenergic antagonist (propranolol, 2 or 5 mg/kg) (all administered IP 0.5 h after the last injection of imipramine) suggested imipramine's adverse effects were mediated by alpha 2 receptors. The possible involvement of the locus ceruleus in these effects was considered.

  6. T-helper cell-mediated factors in drug-induced liver injury.

    PubMed

    Wang, Xinzhi; Zhang, Luyong; Jiang, Zhenzhou

    2015-07-01

    Drug-induced liver injury (DILI) leads to a large burden on the healthcare system due to its potential morbidity and mortality. The key for predicting and preventing DILI is to understand the underlying mechanisms. Hepatic inflammation is one of the most common features of DILI. The inflammation can be attributed to the innate immune response. The adaptive immune system is also affected by the innate immune response resulting in liver damage. T-helper cells are important regulators of acquired immunity. T-helper cell-mediated immune responses play pivotal roles in the pathogenesis of a variety of liver disorders. This review summarizes recent advances in the T-helper cell-mediated factors in DILI and potential mechanisms, which may lead to a better understanding of DILI. PMID:25752261

  7. 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

  8. A pain-mediated neural signal induces relapse in murine autoimmune encephalomyelitis, a multiple sclerosis model

    PubMed Central

    Arima, Yasunobu; Kamimura, Daisuke; Atsumi, Toru; Harada, Masaya; Kawamoto, Tadafumi; Nishikawa, Naoki; Stofkova, Andrea; Ohki, Takuto; Higuchi, Kotaro; Morimoto, Yuji; Wieghofer, Peter; Okada, Yuka; Mori, Yuki; Sakoda, Saburo; Saika, Shizuya; Yoshioka, Yoshichika; Komuro, Issei; Yamashita, Toshihide; Hirano, Toshio; Prinz, Marco; Murakami, Masaaki

    2015-01-01

    Although pain is a common symptom of various diseases and disorders, its contribution to disease pathogenesis is not well understood. Here we show using murine experimental autoimmune encephalomyelitis (EAE), a model for multiple sclerosis (MS), that pain induces EAE relapse. Mechanistic analysis showed that pain induction activates a sensory-sympathetic signal followed by a chemokine-mediated accumulation of MHC class II+CD11b+ cells that showed antigen-presentation activity at specific ventral vessels in the fifth lumbar cord of EAE-recovered mice. Following this accumulation, various immune cells including pathogenic CD4+ T cells recruited in the spinal cord in a manner dependent on a local chemokine inducer in endothelial cells, resulting in EAE relapse. Our results demonstrate that a pain-mediated neural signal can be transformed into an inflammation reaction at specific vessels to induce disease relapse, thus making this signal a potential therapeutic target. DOI: http://dx.doi.org/10.7554/eLife.08733.001 PMID:26193120

  9. 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

  10. Interleukin-12 induces sustained activation of multiple host inflammatory mediator systems in chimpanzees.

    PubMed

    Lauw, F N; Dekkers, P E; te Velde, A A; Speelman, P; Levi, M; Kurimoto, M; Hack, C E; van Deventer, S J; van der Poll, T

    1999-03-01

    To determine in vivo effects of interleukin (IL)-12 on host inflammatory mediator systems, 4 healthy chimpanzees received recombinant human IL-12 (1 microg/kg) by intravenous injection. IL-12 induced increases in plasma concentrations of IL-15, IL-18, and interferon-gamma (IFN-gamma), plus a marked antiinflammatory cytokine response (IL-10, soluble tumor necrosis factor [TNF] receptors, IL-1 receptor antagonist) and secretion of alpha-chemokines (IL-8, IFN-gamma-inducible protein 10) and beta-chemokines (monocyte chemoattractant protein-1, macrophage inflammatory protein-1beta). In addition, IL-12 elicited neutrophilic leukocytosis, neutrophil degranulation (elastase-alpha1-antitrypsin complexes), coagulation activation (F1 + 2 prothrombin fragment, thrombin-antithrombin III complexes), and fibrinolytic activation (tissue-type plasminogen activator, plasmin-alpha2-antiplasmin complexes). IL-12-induced activation of multiple host mediator systems was found only after 8-24 h, remained detectable until the end of the 48-h observation period, and occurred in the absence of detectable TNF and IL-1beta. These data may contribute to understanding the role of IL-12 in the pathogenesis of sepsis syndrome and the toxicity found after repeated injections of IL-12.

  11. Role of TLR2- and TLR4-mediated signaling in Mycobacterium tuberculosis-induced macrophage death.

    PubMed

    Sánchez, Dulfary; Rojas, Mauricio; Hernández, Israel; Radzioch, Danuta; García, Luis F; Barrera, Luis F

    2010-01-01

    Infection of macrophages with Mycobacterium tuberculosis (Mtb) induces cell death by apoptosis or necrosis. TLRs 2 and 4 recognition of mycobacterial ligands has been independently associated to apoptosis induction. To try to understand the particular contribution of these receptors to apoptotic or necrotic signaling upon infection with live Mtb H37Rv, we used macrophage lines derived from wild-type or TLR2-, TLR4-, and MyD88-deficient mouse strains. Mtb-infection triggered apoptosis depending on a TLR2/TLR4/MyD88/p38/ERK/PI-3K/NF-kB pathway; however, necrosis was favored in absence of TLR4 signaling independently of p38, ERK1/2, PI-3K or NF-kappaB activity. In conclusion, our results indicate that cooperation between TLR2- and TLR4-dependent mediated signals play a critical role in macrophage apoptosis induced by Mtb and the TLR4-mediated signaling has important role in the maintenance of the balance between apoptotic vs. necrotic cell death induced by macrophage infection with Mtb.

  12. Oncolytic and immunotherapeutic vaccinia induces antibody-mediated complement-dependent cancer cell lysis in humans.

    PubMed

    Kim, Mi Kyung; Breitbach, Caroline J; Moon, Anne; Heo, Jeong; Lee, Yu Kyoung; Cho, Mong; Lee, Jun Woo; Kim, Seong-Geun; Kang, Dae Hwan; Bell, John C; Park, Byeong Ho; Kirn, David H; Hwang, Tae-Ho

    2013-05-15

    Oncolytic viruses cause direct cytolysis and cancer-specific immunity in preclinical models. The goal of this study was to demonstrate induction of functional anticancer immunity that can lyse target cancer cells in humans. Pexa-Vec (pexastimogene devacirepvec; JX-594) is a targeted oncolytic and immunotherapeutic vaccinia virus engineered to express human granulocyte-macrophage colony-stimulating factor (GM-CSF). Pexa-Vec demonstrated replication, GM-CSF expression, and tumor responses in previous phase 1 trials. We now evaluated whether Pexa-Vec induced functional anticancer immunity both in the rabbit VX2 tumor model and in patients with diverse solid tumor types in phase 1. Antibody-mediated complement-dependent cancer cell cytotoxicity (CDC) was induced by intravenous Pexa-Vec in rabbits; transfer of serum from Pexa-Vec-treated animals to tumor-bearing animals resulted in tumor necrosis and improved survival. In patients with diverse tumor types treated on a phase 1 trial, CDC developed within 4 to 8 weeks in most patients; normal cells were resistant to the cytotoxic effects. T lymphocyte activation in patients was evidenced by antibody class switching. We determined that patients with the longest survival duration had the highest CDC activity, and identified candidate target tumor cell antigens. Thus, we demonstrated that Pexa-Vec induced polyclonal antibody-mediated CDC against multiple tumor antigens both in rabbits and in patients with diverse solid tumor types.

  13. Fenugreek induced apoptosis in breast cancer MCF-7 cells mediated independently by fas receptor change.

    PubMed

    Alshatwi, Ali Abdullah; Shafi, Gowhar; Hasan, Tarique Noorul; Syed, Naveed Ahmed; Khoja, Kholoud Khalid

    2013-01-01

    Trigonella foenum in graecum (Fenugreek) is a traditional herbal plant used to treat disorders like diabetes, high cholesterol, wounds, inflammation, gastrointestinal ailments, and it is believed to have anti-tumor properties, although the mechanisms for the activity remain to be elucidated. In this study, we prepared a methanol extract from Fenugreek whole plants and investigated the mechanism involved in its growth-inhibitory effect on MCF- 7 human breast cancer cells. Apoptosis of MCF-7 cells was evidenced by investigating trypan blue exclusion, TUNEL and Caspase 3, 8, 9, p53, FADD, Bax and Bak by real-time PCR assays inducing activities, in the presence of FME at 65 μg/mL for 24 and 48 hours. FME induced apoptosis was mediated by the death receptor pathway as demonstrated by the increased level of Fas receptor expression after FME treatment. However, such change was found to be absent in Caspase 3, 8, 9, p53, FADD, Bax and Bak, which was confirmed by a time-dependent and dose-dependent manner. In summary, these data demonstrate that at least 90% of FME induced apoptosis in breast cell is mediated by Fas receptor-independently of either FADD, Caspase 8 or 3, as well as p53 interdependently. PMID:24289578

  14. Tumor necrosis factor and interleukin 1 as mediators of endotoxin-induced beneficial effects

    SciTech Connect

    Urbaschek, R.; Urbaschek, B.

    1987-09-01

    Bacterial lipopolysaccharides or endotoxins are known to induce tumor necrosis; enhanced nonspecific resistance to bacterial, viral, and parasitic infections and to radiation sickness; and tolerance to lethal doses of endotoxin. These beneficial effects are achieved by pretreatment with minute amounts of endotoxin. Recombinant tumor necrosis factor (TNF) and interleukin 1 (IL-1) are among the mediators capable of invoking radioprotection or resistance to the consequences of cecal ligation and puncture. Both cytokines are potent inducers of serum colony-stimulating factor (CSF) in C3H/HeJ mice (low responders to endotoxin). The number of splenic granulocyte-macrophage precursors was found to increase 5 days after injection of TNF in these mice. Although with IL-1 no increase in the number of granulocyte-macrophage colonies occurred in culture in the presence of serum CSF, a marked stimulation was observed when TNF was added. This stimulation of myelopoiesis observed in vivo and in vitro may be related to the radioprotective effect of TNF. The data presented suggest that TNF and IL-1 released after injection of endotoxin participate in the mediation of endotoxin-induced enhancement of nonspecific resistance and stimulation of hematopoiesis. 76 references.

  15. Isoalantolactone Induces Reactive Oxygen Species Mediated Apoptosis in Pancreatic Carcinoma PANC-1 Cells

    PubMed Central

    Khan, Muhammad; Ding, Chuan; Rasul, Azhar; Yi, Fei; Li, Ting; Gao, Hongwen; Gao, Rong; Zhong, Lili; Zhang, Kun; Fang, Xuedong; Ma, Tonghui

    2012-01-01

    Isoalantolactone, a sesquiterpene lactone compound possesses antifungal, antibacteria, antihelminthic and antiproliferative activities. In the present study, we found that isoalantolactone inhibits growth and induces apoptosis in pancreatic cancer cells. Further mechanistic studies revealed that induction of apoptosis is associated with increased generation of reactive oxygen species, cardiolipin oxidation, reduced mitochondrial membrane potential, release of cytochrome c and cell cycle arrest at S phase. N-Acetyl Cysteine (NAC), a specific ROS inhibitor restored cell viability and completely blocked isoalantolactone-mediated apoptosis in PANC-1 cells indicating that ROS are involved in isoalantolactone-mediated apoptosis. Western blot study showed that isoalantolactone increased the expression of phosphorylated p38 MAPK, Bax, and cleaved caspase-3 and decreased the expression of Bcl-2 in a dose-dependent manner. No change in expression of phosphorylated p38 MAPK and Bax was found when cells were treated with isoalantolactone in the presence of NAC, indicating that activation of these proteins is directly dependent on ROS generation. The present study provides evidence for the first time that isoalantolactone induces ROS-dependent apoptosis through intrinsic pathway. Furthermore, our in vivo toxicity study demonstrated that isoalantolactone did not induce any acute or chronic toxicity in liver and kidneys of CD1 mice at dose of 100 mg/kg body weight. Therefore, isoalantolactone may be a safe chemotherapeutic candidate for the treatment of human pancreatic carcinoma. PMID:22532787

  16. 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

  17. Invited commentary: boundless science--putting natural direct and indirect effects in a clearer empirical context.

    PubMed

    Naimi, Ashley I

    2015-07-15

    Epidemiologists are increasingly using natural effects for applied mediation analyses, yet 1 key identifying assumption is unintuitive and subject to some controversy. In this issue of the Journal, Jiang and VanderWeele (Am J Epidemiol. 2015;182(2):105-108) formalize the conditions under which the difference method can be used to estimate natural indirect effects. In this commentary, I discuss implications of the controversial "cross-worlds" independence assumption needed to identify natural effects. I argue that with a binary mediator, a simple modification of the authors' approach will provide bounds for natural direct and indirect effect estimates that better reflect the capacity of the available data to support empirical statements on the presence of mediated effects. I discuss complications encountered when odds ratios are used to decompose effects, as well as the implications of incorrectly assuming the absence of exposure-induced mediator-outcome confounders. I note that the former problem can be entirely resolved using collapsible measures of effect, such as risk ratios. In the Appendix, I use previous derivations for natural direct effect bounds on the risk difference scale to provide bounds on the odds ratio scale that accommodate 1) uncertainty due to the cross-world independence assumption and 2) uncertainty due to the cross-world independence assumption and the presence of exposure-induced mediator-outcome confounders.

  18. 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

  19. 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

  20. Aldose Reductase Mediates Endotoxin-Induced Production of Nitric oxide and Cytotoxicity in Murine Macrophages.

    PubMed Central

    Ramana, Kota V; Reddy, Aramati BM.; Tammali, Ravinder; Srivastava, Satish K.

    2007-01-01

    Aldose reductase (AR) is a ubiquitously expressed protein with pleiotrophic roles as an efficient catalyst for the reduction of toxic lipid aldehydes and mediator of hyperglycemia, cytokine and growth factor –induced redox sensitive signals that cause secondary diabetic complications. Although AR inhibition has been shown to be protective against oxidative stress signals, the role of AR in regulating nitric oxide (NO) synthesis and NO-mediated apoptosis has not been elucidated to date. We therefore investigated the role of AR in regulating lipopolysaccharide (LPS)-induced NO synthesis and apoptosis in RAW 264.7 macrophages. Inhibition or RNA interference ablation of AR suppressed LPS-stimulated production of NO and over-expression of iNOS mRNA. Inhibition or ablation of AR also prevented the LPS-induced apoptosis, cell cycle arrest, activation of caspase-3, p38-MAPK, JNK, NF-κB and AP1. In addition, AR inhibition prevented the LPS-induced down-regulation of Bcl-xl and up-regulation of Bax and Bak in macrophages. L-arginine increased and L-NAME decreased the severity of cell death caused by LPS and AR inhibitors prevented it. Furthermore, inhibition of AR prevents cell death caused by HNE and GS-HNE, but not GS-DHN. Our findings for the first time suggest that AR catalyzed lipid aldehyde-glutathione conjugates regulates the LPS-induced production of inflammatory marker NO and cytotoxicity in RAW 264.7 cells. Inhibition or ablation of AR activity may be potential therapeutic target in endotoximia and other inflammatory diseases. PMID:17382209

  1. Activation of calpains mediates early lung neutrophilic inflammation in ventilator-induced lung injury

    PubMed Central

    Liu, Dejie; Yan, Zhibo; Minshall, Richard D.; Schwartz, David E.; Chen, Yuguo

    2012-01-01

    Lung inflammatory responses in the absence of infection are considered to be one of primary mechanisms of ventilator-induced lung injury. Here, we determined the role of calpain in the pathogenesis of lung inflammation attributable to mechanical ventilation. Male C57BL/6J mice were subjected to high (28 ml/kg) tidal volume ventilation for 2 h in the absence and presence of calpain inhibitor I (10 mg/kg). To address the isoform-specific functions of calpain 1 and calpain 2 during mechanical ventilation, we utilized a liposome-based delivery system to introduce small interfering RNAs targeting each isoform in pulmonary vasculature in vivo. Mechanical ventilation with high tidal volume induced rapid (within minutes) and persistent calpain activation and lung inflammation as evidenced by neutrophil recruitment, production of TNF-α and IL-6, pulmonary vascular hyperpermeability, and lung edema formation. Pharmaceutical calpain inhibition significantly attenuated these inflammatory responses caused by lung hyperinflation. Depletion of calpain 1 or calpain 2 had a protective effect against ventilator-induced lung inflammatory responses. Inhibition of calpain activity by means of siRNA silencing or pharmacological inhibition also reduced endothelial nitric oxide (NO) synthase (NOS-3)-mediated NO production and subsequent ICAM-1 phosphorylation following high tidal volume ventilation. These results suggest that calpain activation mediates early lung inflammation during ventilator-induced lung injury via NOS-3/NO-dependent ICAM-1 phosphorylation and neutrophil recruitment. Inhibition of calpain activation may therefore provide a novel and promising strategy for the prevention and treatment of ventilator-induced lung injury. PMID:22140070

  2. Phospholipase D signaling mediates reactive oxygen species-induced lung endothelial barrier dysfunction.

    PubMed

    Usatyuk, Peter V; Kotha, Sainath R; Parinandi, Narasimham L; Natarajan, Viswanathan

    2013-01-01

    Reactive oxygen species (ROS) have emerged as critical players in the pathophysiology of pulmonary disorders and diseases. Earlier, we have demonstrated that ROS stimulate lung endothelial cell (EC) phospholipase D (PLD) that generates phosphatidic acid (PA), a second messenger involved in signal transduction. In the current study, we investigated the role of PLD signaling in the ROS-induced lung vascular EC barrier dysfunction. Our results demonstrated that hydrogen peroxide (H2O2), a typical physiological ROS, induced PLD activation and altered the barrier function in bovine pulmonary artery ECs (BPAECs). 1-Butanol, the quencher of PLD, generated PA leading to the formation of physiologically inactive phosphatidyl butanol but not its biologically inactive analog, 2-butanol, blocked the H2O2-mediated barrier dysfunction. Furthermore, cell permeable C2 ceramide, an inhibitor of PLD but not the C2 dihydroceramide, attenuated the H2O2-induced PLD activation and enhancement of paracellular permeability of Evans blue conjugated albumin across the BPAEC monolayers. In addition, transfection of BPAECs with adenoviral constructs of hPLD1 and mPLD2 mutants attenuated the H2O2-induced barrier dysfunction, cytoskeletal reorganization and distribution of focal adhesion proteins. For the first time, this study demonstrated that the PLD-generated intracellular bioactive lipid signal mediator, PA, played a critical role in the ROS-induced barrier dysfunction in lung vascular ECs. This study also underscores the importance of PLD signaling in vascular leak and associated tissue injury in the etiology of lung diseases among critically ill patients encountering oxygen toxicity and excess ROS production during ventilator-assisted breathing.

  3. Glucose transporter 8 (GLUT8) mediates fructose-induced de novo lipogenesis and macrosteatosis.

    PubMed

    Debosch, Brian J; Chen, Zhouji; Saben, Jessica L; Finck, Brian N; Moley, Kelle H

    2014-04-18

    Non-alcoholic fatty liver disease (NAFLD) is the most common liver disease in the world, and it is thought to be the hepatic manifestation of the metabolic syndrome. Excess dietary fructose causes both metabolic syndrome and NAFLD in rodents and humans, but the pathogenic mechanisms of fructose-induced metabolic syndrome and NAFLD are poorly understood. GLUT8 (Slc2A8) is a facilitative glucose and fructose transporter that is highly expressed in liver, heart, and other oxidative tissues. We previously demonstrated that female mice lacking GLUT8 exhibit impaired first-pass hepatic fructose metabolism, suggesting that fructose transport into the hepatocyte, the primary site of fructose metabolism, is in part mediated by GLUT8. Here, we tested the hypothesis that GLUT8 is required for hepatocyte fructose uptake and for the development of fructose-induced NAFLD. We demonstrate that GLUT8 is a cell surface-localized transporter and that GLUT8 overexpression or GLUT8 shRNA-mediated gene silencing significantly induces and blocks radiolabeled fructose uptake in cultured hepatocytes. We further show diminished fructose uptake and de novo lipogenesis in fructose-challenged GLUT8-deficient hepatocytes. Finally, livers from long term high-fructose diet-fed GLUT8-deficient mice exhibited attenuated fructose-induced hepatic triglyceride and cholesterol accumulation without changes in hepatocyte insulin-stimulated Akt phosphorylation. GLUT8 is thus essential for hepatocyte fructose transport and fructose-induced macrosteatosis. Fructose delivery across the hepatocyte membrane is thus a proximal, modifiable disease mechanism that may be exploited to prevent NAFLD.

  4. 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

  5. Renal tubular Fas ligand mediates fratricide in cisplatin-induced acute kidney failure.

    PubMed

    Linkermann, Andreas; Himmerkus, Nina; Rölver, Lars; Keyser, Kirsten A; Steen, Philip; Bräsen, Jan-Hinrich; Bleich, Markus; Kunzendorf, Ulrich; Krautwald, Stefan

    2011-01-01

    Cisplatin, a standard chemotherapeutic agent for many tumors, has an unfortunately common toxicity where almost a third of patients develop renal dysfunction after a single dose. Acute kidney injury caused by cisplatin depends on Fas-mediated apoptosis driven by Fas ligand (FasL) expressed on tubular epithelial and infiltrating immune cells. Since the role of FasL in T cells is known, we investigated whether its presence in primary kidney cells is needed for its toxic effect. We found that all cisplatin-treated wild-type (wt) mice died within 6 days; however, severe combined immunodeficiency (SCID)/beige mice (B-, T-, and natural killer-cell-deficient) displayed a significant survival benefit, with only 55% mortality while exhibiting significant renal failure. Treating SCID/beige mice with MFL3, a FasL-blocking monoclonal antibody, completely restored survival after an otherwise lethal cisplatin dose, suggesting another source of FasL besides immune cells. Freshly isolated primary tubule segments from wt mice were co-incubated with thick ascending limb (TAL) segments freshly isolated from mice expressing the green fluorescent protein (GFP) transgene (same genetic background) to determine whether FasL-mediated killing of tubular cells is an autocrine or paracrine mechanism. Cisplatin-stimulated primary segments induced apoptosis in the GFP-tagged TAL cells, an effect blocked by MFL3. Thus, our study shows that cisplatin-induced nephropathy is mediated through FasL, functionally expressed on tubular cells that are capable of inducing death of cells of adjacent tubules. PMID:20811331

  6. 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.

  7. Phytochromes A and B mediate red-light-induced positive phototropism in roots.

    PubMed

    Kiss, John Z; Mullen, Jack L; Correll, Melanie J; Hangarter, Roger P

    2003-03-01

    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.

  8. Indirect posterior composite resins.

    PubMed

    Leinfelder, Karl F

    2005-07-01

    The use of indirect posterior composite restorations has facilitated the generation of ideal anatomic form, marginal adaptation, and appropriate proximal contact and contour. Unfortunately, however, the use of post-cure heat treatments has done little to enhance the overall clinical performance of the restoration. The development of new curing techniques in conjunction with modifications of the formulae have contributed to a substantial improvement in both the mechanical characteristics and long-term clinical performance of indirect posterior composite resins.

  9. Autocrine TGFbeta signaling mediates vitamin D3 analog-induced growth inhibition in breast cells.

    PubMed

    Yang, L; Yang, J; Venkateswarlu, S; Ko, T; Brattain, M G

    2001-09-01

    In this study, we address whether TGFbeta signaling mediates vitamin D3 analog-induced growth inhibition in nonmalignant and malignant breast cells. Normal mammary epithelial cells (184), immortalized nonmalignant mammary epithelial cells (184A1 and MCF10A), and breast cancer cells (early passage MCF7: MCF7E) were sensitive to the inhibitory effects of vitamin D3 analogs (EB1089 and MC1288) while late passage MCF7 breast cancer (MCF7L) cells were relatively resistant. A similar pattern of sensitivity to TGFbeta was observed with these cells. Thus, the sensitivity to the vitamin D3 analogs correlated with the sensitivity to TGFbeta. MCF7L TGFbetaRII-transfected cells, which have autocrine TGFbeta activity, were more sensitive to EB1089 than MCF7L cells. TGFbeta neutralizing antibody was found to block the inhibitory effects of these analogs. These results are consistent with the idea that autocrine TGFbeta signaling mediates the anti-proliferative effects of the vitamin D3 analogs in these cells. The expression of TGFbeta isoforms and/or TGFbeta receptors was induced by the analogs in the vitamin D3 and TGFbeta sensitive cells. Vitamin D3 analogs did not induce TGFbeta or TGFbeta receptor expression in the resistant MCF7L cells. Therefore, EB1089 induces autocrine TGFbeta activity through increasing expression of TGFbeta isoforms and/or TGFbeta receptors. In addition, EB1089 induced nuclear VDR protein levels in the sensitive 184A1 cells but not in the resistant MCF7L cells. 184A1 cells were more sensitive to EB1089-induced VDR-dependent transactivation than MCF7L cells as measured by a luciferase reporter construct containing the VDRE, indicating a defect of VDR signaling in MCF7L cells. Smad3, a TGFbeta signaling mediator, coactivated VDR-dependent transactivation in 184A1 cells but not in MCF7L cells. These results indicate that Smad3 coactivates VDR to further enhance TGFbeta signaling and vitamin D3 signaling in the sensitive 184A1 cells. The results also

  10. Proteasome-mediated degradation antagonizes critical levels of the apoptosis-inducing C1D protein

    PubMed Central

    Rothbarth, Karsten; Stammer, Hermann; Werner, Dieter

    2002-01-01

    The C1D gene is expressed in a broad spectrum of mammalian cells and tissues but its product induces apoptotic cell death when exceeding a critical level. Critical levels are achieved in a fraction of cells by transient transfection with EGFP-tagged C1D expression constructs. However, transfected cells expressing sub-critical levels of C1D(EGFP) escape apoptotic cell death by activation of a proteasome-mediated rescue mechanism. Inhibition of the proteasome-dependent degradation of the C1D(EGFP) protein results in a parallel increase of the intracellular C1D level and in the fraction of apoptotic cells. PMID:12379155

  11. 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.

  12. Caspase-2 mediates a Brucella abortus RB51-induced hybrid cell death having features of apoptosis and pyroptosis

    PubMed Central

    Bronner, Denise N.; O'Riordan, Mary X. D.; He, Yongqun

    2013-01-01

    Programmed cell death (PCD) can play a crucial role in tuning the immune response to microbial infection. Although PCD can occur in different forms, all are mediated by a family of proteases called caspases. Caspase-2 is the most conserved caspase, however, its function in cell death is ill-defined. Previously we demonstrated that live attenuated cattle vaccine strain Brucella abortus RB51 induces caspase-2-mediated and caspase-1-independent PCD of infected macrophages. We also discovered that rough attenuated B. suis strain VTRS1 induces a caspase-2-mediated and caspase-1-independent proinflammatory cell death in infected macrophages, which was tentatively coined “caspase-2-mediated pyroptosis”. However, the mechanism of caspase-2-mediated cell death pathway remained unclear. In this study, we found that caspase-2 mediated proinflammatory cell death of RB51-infected macrophages and regulated many genes in different PCD pathways. We show that the activation of proapoptotic caspases-3 and -8 was dependent upon caspase-2. Caspase-2 regulated mitochondrial cytochrome c release and TNFα production, both of which are known to activate caspase-3 and caspase-8, respectively. In addition to TNFα, RB51-induced caspase-1 and IL-1β production was also driven by caspase-2-mediated mitochondrial dysfunction. Interestingly, pore formation, a phenomenon commonly associated with caspase-1-mediated pyroptosis, occurred; however, unlike its role in S. typhimurium-induced pyroptosis, pore formation did not contribute to RB51-induced proinflammatory cell death. Our data suggest that caspase-2 acts as an initiator caspase that mediates a novel RB51-induced hybrid cell death that simulates but differs from typical non-proinflammatory apoptosis and caspase-1-mediated proinflammatory pyroptosis. The initiator role of the caspase-2-mediated cell death was also conserved in cellular stress-induced cell death of macrophages treated with etoposide, naphthalene, or anti-Fas. Caspase-2

  13. CD38-mediated Ca(2+) signaling contributes to glucagon-induced hepatic gluconeogenesis.

    PubMed

    Rah, So-Young; Kim, Uh-Hyun

    2015-06-03

    CD38 is a multifunctional enzyme for the synthesis of Ca(2+) second messengers. Glucagon promotes hepatic glucose production through Ca(2+) signaling in the fasting condition. In this study, we investigated the role of CD38 in the glucagon signaling of hepatocytes. Here, we show that glucagon induces cyclic ADP-ribose (cADPR) production and sustained Ca(2+) increases via CD38 in hepatocytes. 8-Br-cADPR, an antagonistic cADPR analog, completely blocked glucagon-induced Ca(2+) increases and phosphorylation of cAMP response element-binding protein (CREB). Moreover, glucagon-induced sustained Ca(2+) signals and translocation of CREB-regulated transcription coactivator 2 to the nucleus were absent and glucagon-induced glucose production and expression of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (Pck1) are remarkably reduced in hepatocytes from CD38(-/-) mice. Furthermore, in the fasting condition, CD38(-/-) mice have decreased blood glucose and hepatic expression of G6Pase and Pck1 compared to wild type mice. Our data suggest that CD38/cADPR-mediated Ca(2+) signals play a key role in glucagon-induced gluconeogenesis in hepatocytes, and that the signal pathway has significant clinical implications in metabolic diseases, including type 2 diabetes.

  14. Severe hypoglycemia-induced lethal cardiac arrhythmias are mediated by sympathoadrenal activation.

    PubMed

    Reno, Candace M; Daphna-Iken, Dorit; Chen, Y Stefanie; VanderWeele, Jennifer; Jethi, Krishan; Fisher, Simon J

    2013-10-01

    For people with insulin-treated diabetes, severe hypoglycemia can be lethal, though potential mechanisms involved are poorly understood. To investigate how severe hypoglycemia can be fatal, hyperinsulinemic, severe hypoglycemic (10-15 mg/dL) clamps were performed in Sprague-Dawley rats with simultaneous electrocardiogram monitoring. With goals of reducing hypoglycemia-induced mortality, the hypotheses tested were that: 1) antecedent glycemic control impacts mortality associated with severe hypoglycemia; 2) with limitation of hypokalemia, potassium supplementation could limit hypoglycemia-associated deaths; 3) with prevention of central neuroglycopenia, brain glucose infusion could prevent hypoglycemia-associated arrhythmias and deaths; and 4) with limitation of sympathoadrenal activation, adrenergic blockers could prevent hypoglycemia-induced arrhythmic deaths. Severe hypoglycemia-induced mortality was noted to be worsened by diabetes, but recurrent antecedent hypoglycemia markedly improved the ability to survive an episode of severe hypoglycemia. Potassium supplementation tended to reduce mortality. Severe hypoglycemia caused numerous cardiac arrhythmias including premature ventricular contractions, tachycardia, and high-degree heart block. Intracerebroventricular glucose infusion reduced severe hypoglycemia-induced arrhythmias and overall mortality. β-Adrenergic blockade markedly reduced cardiac arrhythmias and completely abrogated deaths due to severe hypoglycemia. Under conditions studied, sudden deaths caused by insulin-induced severe hypoglycemia were mediated by lethal cardiac arrhythmias triggered by brain neuroglycopenia and the marked sympathoadrenal response.

  15. Oxidant-induced apoptosis is mediated by oxidation of the actin-regulatory protein cofilin

    PubMed Central

    Klamt, Fábio; Zdanov, Stéphanie; Levine, Rodney L.; Pariser, Ashley; Zhang, Yaqin; Zhang, Baolin; Yu, Li-Rong; Veenstra, Timothy D.; Shacter, Emily

    2012-01-01

    Physiological oxidants that are generated by activated phagocytes comprise the main source of oxidative stress during inflammation1,2. Oxidants such as taurine chloramine (TnCl) and hydrogen peroxide (H2O2) can damage proteins and induce apoptosis, but the role of specific protein oxidation in this process has not been defined. We found that the actin-binding protein cofilin is a key target of oxidation. When oxidation of this single regulatory protein is prevented, oxidant-induced apoptosis is inhibited. Oxidation of cofilin causes it to lose its affinity for actin and to translocate to the mitochondria, where it induces swelling and cytochrome c release by mediating opening of the permeability transition pore (PTP). This occurs independently of Bax activation and requires both oxidation of cofilin Cys residues and dephosphorylation at Ser 3. Knockdown of endogenous cofilin using targeted siRNA inhibits oxidant-induced apoptosis, which is restored by re-expression of wild-type cofilin but not by cofilin containing Cys to Ala mutations. Exposure of cofilin to TnCl results in intramolecular disulphide bonding and oxidation of Met residues to Met sulphoxide, but only Cys oxidation causes cofilin to induce mitochondrial damage. PMID:19734890

  16. BH3-only protein BIM mediates heat shock-induced apoptosis.

    PubMed

    Mahajan, Indra M; Chen, Miao-Der; Muro, Israel; Robertson, John D; Wright, Casey W; Bratton, Shawn B

    2014-01-01

    Acute heat shock can induce apoptosis through a canonical pathway involving the upstream activation of caspase-2, followed by BID cleavage and stimulation of the intrinsic pathway. Herein, we report that the BH3-only protein BIM, rather than BID, is essential to heat shock-induced cell death. We observed that BIM-deficient cells were highly resistant to heat shock, exhibiting short and long-term survival equivalent to Bax(-/-)Bak(-/-) cells and better than either Bid(-/-) or dominant-negative caspase-9-expressing cells. Only Bim(-/-) and Bax(-/-)Bak(-/-) cells exhibited resistance to mitochondrial outer membrane permeabilization and loss of mitochondrial inner membrane potential. Moreover, while dimerized caspase-2 failed to induce apoptosis in Bid(-/-) cells, it readily did so in Bim(-/-) cells, implying that caspase-2 kills exclusively through BID, not BIM. Finally, BIM reportedly associates with MCL-1 following heat shock, and Mcl-1(-/-) cells were indeed sensitized to heat shock-induced apoptosis. However, pharmacological inhibition of BCL-2 and BCL-X(L) with ABT-737 also sensitized cells to heat shock, most likely through liberation of BIM. Thus, BIM mediates heat shock-induced apoptosis through a BAX/BAK-dependent pathway that is antagonized by antiapoptotic BCL-2 family members.

  17. CD38-mediated Ca2+ signaling contributes to glucagon-induced hepatic gluconeogenesis

    PubMed Central

    Rah, So-Young; Kim, Uh-Hyun

    2015-01-01

    CD38 is a multifunctional enzyme for the synthesis of Ca2+ second messengers. Glucagon promotes hepatic glucose production through Ca2+ signaling in the fasting condition. In this study, we investigated the role of CD38 in the glucagon signaling of hepatocytes. Here, we show that glucagon induces cyclic ADP-ribose (cADPR) production and sustained Ca2+ increases via CD38 in hepatocytes. 8-Br-cADPR, an antagonistic cADPR analog, completely blocked glucagon-induced Ca2+ increases and phosphorylation of cAMP response element-binding protein (CREB). Moreover, glucagon-induced sustained Ca2+ signals and translocation of CREB-regulated transcription coactivator 2 to the nucleus were absent and glucagon-induced glucose production and expression of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (Pck1) are remarkably reduced in hepatocytes from CD38−/− mice. Furthermore, in the fasting condition, CD38−/− mice have decreased blood glucose and hepatic expression of G6Pase and Pck1 compared to wild type mice. Our data suggest that CD38/cADPR-mediated Ca2+ signals play a key role in glucagon-induced gluconeogenesis in hepatocytes, and that the signal pathway has significant clinical implications in metabolic diseases, including type 2 diabetes. PMID:26038839

  18. Secreted tyrosine sulfated-eIF5A mediates oxidative stress-induced apoptosis

    PubMed Central

    Seko, Yoshinori; Fujimura, Tsutomu; Yao, Takako; Taka, Hikari; Mineki, Reiko; Okumura, Ko; Murayama, Kimie

    2015-01-01

    Oxidative stress plays a critical role in ischemia/reperfusion-injury, atherosclerosis, and aging. It causes cell damage that leads to apoptosis via uncertain mechanisms. Because conditioned medium from cardiac myocytes subjected to hypoxia/reoxygenation induces extensive apoptosis of cardiac myocytes under normoxia, we hypothesized that a humoral factor released from the hypoxic/reoxygenated cardiac myocytes mediates apoptosis. We identified an apoptosis-inducing humoral factor in the hypoxia/reoxygenation-conditioned medium. Here, we found that eIF5A undergoes tyrosine sulfation in the trans-Golgi and is rapidly secreted from cardiac myocytes in response to hypoxia/reoxygenation; then, eIF5A induces apoptosis by acting as a pro-apoptotic ligand. The apoptosis of cardiac myocytes induced by hypoxia/reoxygenation or ultraviolet irradiation was suppressed by anti-eIF5A neutralizing monoclonal antibodies (mAbs) in vitro. Myocardial ischemia/reperfusion (but not ischemia alone) markedly increased the plasma levels of eIF5A, and treatment with anti-eIF5A neutralizing mAbs significantly reduced myocardial injury. These results identify an important, novel specific biomarker and a critical therapeutic target for oxidative stress-induced cell injury. PMID:26348594

  19. 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

  20. Fluoride induces oxidative damage and SIRT1/autophagy through ROS-mediated JNK signaling.

    PubMed

    Suzuki, Maiko; Bandoski, Cheryl; Bartlett, John D

    2015-12-01

    Fluoride is an effective caries prophylactic, but at high doses can also be an environmental health hazard. Acute or chronic exposure to high fluoride doses can result in dental enamel and skeletal and soft tissue fluorosis. Dental fluorosis is manifested as mottled, discolored, porous enamel that is susceptible to dental caries. Fluoride induces cell stress, including endoplasmic reticulum stress and oxidative stress, which leads to impairment of ameloblasts responsible for dental enamel formation. Recently we reported that fluoride activates SIRT1 and autophagy as an adaptive response to protect cells from stress. However, it still remains unclear how SIRT1/autophagy is regulated in dental fluorosis. In this study, we demonstrate that fluoride exposure generates reactive oxygen species (ROS) and the resulting oxidative damage is counteracted by SIRT1/autophagy induction through c-Jun N-terminal kinase (JNK) signaling in ameloblasts. In the mouse-ameloblast-derived cell line LS8, fluoride induced ROS, mitochondrial damage including cytochrome-c release, up-regulation of UCP2, attenuation of ATP synthesis, and H2AX phosphorylation (γH2AX), which is a marker of DNA damage. We evaluated the effects of the ROS inhibitor N-acetylcysteine (NAC) and the JNK inhibitor SP600125 on fluoride-induced SIRT1/autophagy activation. NAC decreased fluoride-induced ROS generation and attenuated JNK and c-Jun phosphorylation. NAC decreased SIRT1 phosphorylation and formation of the autophagy marker LC3II, which resulted in an increase in the apoptosis mediators γH2AX and cleaved/activated caspase-3. SP600125 attenuated fluoride-induced SIRT1 phosphorylation, indicating that fluoride activates SIRT1/autophagy via the ROS-mediated JNK pathway. In enamel organs from rats or mice treated with 50, 100, or 125 ppm fluoride for 6 weeks, cytochrome-c release and the DNA damage markers 8-oxoguanine, p-ATM, and γH2AX were increased compared to those in controls (0 ppm fluoride). These

  1. Indirect-direct anticrossing in GaAs-AlAs superlattices induced by an electric field: Evidence of GAMMA-X mixing

    SciTech Connect

    Meynadier, M.; Nahory, R.E.; Worlock, J.M.; Tamargo, M.C.; de Miguel, J.L.; Sturge, M.D.

    1988-03-28

    We demonstrate that a GaAs-AlAs superlattice can be switched from indirect to direct, in both real and reciprocal spaces, by application of a modest axial electric field. The crossover region is found to be an anticrossing, manifesting the presence of GAMMA-X mixing by a potential measured to be of the order of 1 meV. This value is corroborated by time-decay measurements performed on different superlattices.

  2. 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.

  3. 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

  4. Cold-inducible RNA-binding protein is an important mediator of alcohol-induced brain inflammation.

    PubMed

    Rajayer, Salil R; Jacob, Asha; Yang, Weng-Lang; Zhou, Mian; Chaung, Wayne; Wang, Ping

    2013-01-01

    Binge drinking has been associated with cerebral dysfunction. Ethanol induced microglial activation initiates an inflammatory process that causes upregulation of proinflammatory cytokines which in turn creates neuronal inflammation and damage. However, the molecular mechanism is not fully understood. We postulate that cold-inducible RNA-binding protein (CIRP), a novel proinflammatory molecule, can contribute to alcohol-induced neuroinflammation. To test this theory male wild-type (WT) mice were exposed to alcohol at concentrations consistent to binge drinking and blood and brain tissues were collected. At 5 h after alcohol, a significant increase of 53% in the brain of CIRP mRNA was observed and its expression remained elevated at 10 h and 15 h. Brain CIRP protein levels were increased by 184% at 10 h and remained high at 15 h. We then exposed male WT and CIRP knockout (CIRP(-/-)) mice to alcohol, and blood and brain tissues were collected at 15 h post-alcohol infusion. Serum levels of tissue injury markers (AST, ALT and LDH) were significantly elevated in alcohol-exposed WT mice while they were less increased in the CIRP(-/-) mice. Brain TNF-α mRNA and protein expressions along with IL-1β protein levels were significantly increased in WT mice, which was not seen in the CIRP(-/-) mice. In cultured BV2 cells (mouse microglia), ethanol at 100 mM showed an increase of CIRP mRNA by 274% and 408% at 24 h and 48 h respectively. Corresponding increases in TNF-α and IL-1β were also observed. CIRP protein levels were markedly increased in the medium, suggesting that CIRP was secreted by the BV2 cells. From this we conclude that alcohol exposure activates microglia to produce and secrete CIRP and possibly induce pro-inflammatory response and thereby causing neuroinflammation. CIRP could be a novel mediator of alcohol-induced brain inflammation.

  5. 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

  6. 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

  7. Protein kinase C-mediated sodium glucose transporter 1 activation in precondition-induced cardioprotection

    PubMed Central

    Kanwal, Abhinav; Kasetti, Sujatha; Putcha, Uday Kumar; Asthana, Shailendra; Banerjee, Sanjay K

    2016-01-01

    The concept of cardioprotection through preconditioning against ischemia–reperfusion (I/R) injury is well known and established. However, among different proposed mechanisms regarding the concept of ischemic preconditioning, protein kinase C (PKC)-mediated cardioprotection through ischemic preconditioning plays a key role in myocardial I/R injury. Thus, this study was designed to find the relationship between PKC and sodium glucose transporter 1 (SGLT1) in preconditioning-induced cardioprotection, which is ill reported till now. By applying a multifaceted approach, we demonstrated that PKC activates SGLT1, which curbed oxidative stress and apoptosis against I/R injury. PKC activation enhances cardiac glucose uptake through SGLT1 and seems essential in preventing I/R-induced cardiac injury, indicating a possible cross-talk between PKC and SGLT1.

  8. Protein kinase C-mediated sodium glucose transporter 1 activation in precondition-induced cardioprotection

    PubMed Central

    Kanwal, Abhinav; Kasetti, Sujatha; Putcha, Uday Kumar; Asthana, Shailendra; Banerjee, Sanjay K

    2016-01-01

    The concept of cardioprotection through preconditioning against ischemia–reperfusion (I/R) injury is well known and established. However, among different proposed mechanisms regarding the concept of ischemic preconditioning, protein kinase C (PKC)-mediated cardioprotection through ischemic preconditioning plays a key role in myocardial I/R injury. Thus, this study was designed to find the relationship between PKC and sodium glucose transporter 1 (SGLT1) in preconditioning-induced cardioprotection, which is ill reported till now. By applying a multifaceted approach, we demonstrated that PKC activates SGLT1, which curbed oxidative stress and apoptosis against I/R injury. PKC activation enhances cardiac glucose uptake through SGLT1 and seems essential in preventing I/R-induced cardiac injury, indicating a possible cross-talk between PKC and SGLT1. PMID:27695290

  9. 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

  10. 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

  11. Heterotrimeric G protein mediates ethylene-induced stomatal closure via hydrogen peroxide synthesis in Arabidopsis.

    PubMed

    Ge, Xiao-Min; Cai, Hong-Li; Lei, Xue; Zhou, Xue; Yue, Ming; He, Jun-Min

    2015-04-01

    Heterotrimeric G proteins function as key players in hydrogen peroxide (H2O2) production in plant cells, but whether G proteins mediate ethylene-induced H2O2 production and stomatal closure are not clear. Here, evidences are provided to show the Gα subunit GPA1 as a missing link between ethylene and H2O2 in guard cell ethylene signalling. In wild-type leaves, ethylene-triggered H2O2 synthesis and stomatal closure were dependent on activation of Gα. GPA1 mutants showed the defect of ethylene-induced H2O2 production and stomatal closure, whereas wGα and cGα overexpression lines showed faster stomatal closure and H2O2 production in response to ethylene. Ethylene-triggered H2O2 generation and stomatal closure were impaired in RAN1, ETR1, ERS1 and EIN4 mutants but not impaired in ETR2 and ERS2 mutants. Gα activator and H2O2 rescued the defect of RAN1 and EIN4 mutants or etr1-3 in ethylene-induced H2O2 production and stomatal closure, but only rescued the defect of ERS1 mutants or etr1-1 and etr1-9 in ethylene-induced H2O2 production. Stomata of CTR1 mutants showed constitutive H2O2 production and stomatal closure, but which could be abolished by Gα inhibitor. Stomata of EIN2, EIN3 and ARR2 mutants did not close in responses to ethylene, Gα activator or H2O2, but do generate H2O2 following challenge of ethylene or Gα activator. The data indicate that Gα mediates ethylene-induced stomatal closure via H2O2 production, and acts downstream of RAN1, ETR1, ERS1, EIN4 and CTR1 and upstream of EIN2, EIN3 and ARR2. The data also show that ETR1 and ERS1 mediate both ethylene and H2O2 signalling in guard cells.

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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?

  17. Arsenate-induced Apoptosis in Murine Embryonic Maxillary Mesenchymal Cells via Mitochondrial Mediated Oxidative Injury

    PubMed Central

    Singh, Saurabh; Greene, Robert M.; Pisano, M. Michele

    2009-01-01

    Background Arsenic is a ubiquitous element that is a potential carcinogen and teratogen and can cause adverse developmental outcomes. Arsenic exerts its toxic effects through the generation of reactive oxygen species (ROS) that include hydrogen peroxide (H2O2), superoxide-derived hydroxyl ion, and peroxyl radicals. However, the molecular mechanisms by which arsenic induces cytotoxicity in murine embryonic maxillary mesenchymal (MEMM) cells are undefined. Methods MEMM cells in culture were treated with different concentrations of pentavalent sodium arsenate [As (V)] for 24 or 48 hours and various end points measured. Results We show that treatment of MEMM cells with the pentavalent form of inorganic arsenic resulted in caspase-mediated apoptosis, accompanied by generation of ROS and disruption of mitochondrial membrane potential. Treatment with caspase inhibitors markedly blocked apoptosis. In addition, the free radical scavenger N-acetylcysteine dramatically attenuated arsenic-mediated ROS production and apoptosis, and exposure to arsenate increased Bax and decreased Bcl protein levels in MEMM cells. Conclusions Taken together, these findings suggest that in MEMM cells, arsenate-mediated oxidative injury acts as an early and upstream initiator of the cell death cascade, triggering cytotoxicity, mitochondrial dysfunction, altered Bcl/Bax protein ratios, and activation of caspase-9. PMID:19739150

  18. Herpesvirus entry mediator regulates hypoxia-inducible factor–1α and erythropoiesis in mice

    PubMed Central

    Sakoda, Yukimi; Anand, Sudarshan; Zhao, Yuming; Park, Jang-June; Liu, Yingjia; Kuramasu, Atsuo; van Rooijen, Nico; Chen, Ling; Strome, Scott E.; Hancock, Wayne W.; Chen, Lieping; Tamada, Koji

    2011-01-01

    Erythropoiesis, the production of red blood cells, must be tightly controlled to ensure adequate oxygen delivery to tissues without causing thrombosis or stroke. Control of physiologic and pathologic erythropoiesis is dependent predominantly on erythropoietin (EPO), the expression of which is regulated by hypoxia-inducible factor (HIF) activity in response to low oxygen tension. Accumulating evidence indicates that oxygen-independent mediators, including inflammatory stimuli, cytokines, and growth factors, also upregulate HIF activity, but it is unclear whether these signals also result in EPO production and erythropoiesis in vivo. Here, we found that signaling through herpesvirus entry mediator (HVEM), a molecule of the TNF receptor superfamily, promoted HIF-1α activity in the kidney and subsequently facilitated renal Epo production and erythropoiesis in vivo under normoxic conditions. This Epo upregulation was mediated by increased production of NO by renal macrophages. Hvem-deficient mice displayed impaired Epo expression and aggravated anemia in response to erythropoietic stress. These data reveal that HVEM signaling functions to promote HIF-1α activity and Epo production, and thus to regulate erythropoiesis. Furthermore, our findings suggest that this molecular mechanism could represent a therapeutic target for Epo-responsive diseases, including anemia. PMID:22080867

  19. Eugenol suppressed the expression of lipopolysaccharide-induced proinflammatory mediators in human macrophages.

    PubMed

    Lee, Ya-Yun; Hung, Shan-Ling; Pai, Sheng-Fang; Lee, Yuan-Ho; Yang, Shue-Fen

    2007-06-01

    Eugenol is commonly used as an analgesic agent during acute pulpitis and is a major component of root canal sealers. Despite the frequent applications of eugenol in the practice of dentistry, little is known about the role of eugenol under the status of inflammation. This study was aimed to investigate the influence of eugenol on human macrophages (U937) under the stimulation of lipopolysaccharide (LPS). Eugenol was shown to block the release of the bone resorbing mediators, including interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and prostaglandin E2 from LPS-stimulated macrophages. In contrast, eugenol alone did not alter the expression levels of these proinflammatory mediators in macrophages. Consistent with downregulation of bone-resorbing mediators, eugenol suppressed the messenger RNA expression of LPS-induced IL-1beta, TNF-alpha, and cyclooxygenase-2 in macrophages. The results suggest a potential anti-inflammatory effect of eugenol in the acute inflamed pulps and apical periodontitis.

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

    PubMed

    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.

  1. HIF-1α Mediates Isoflurane-Induced Vascular Protection in Subarachnoid Hemorrhage

    PubMed Central

    Milner, Eric; Johnson, Andrew W; Nelson, James W; Harries, Michael D; Gidday, Jeffrey M; Han, Byung Hee; Zipfel, Gregory J

    2015-01-01

    Objective Outcome after aneurysmal subarachnoid hemorrhage (SAH) depends critically on delayed cerebral ischemia (DCI) – a process driven primarily by vascular events including cerebral vasospasm, microvessel thrombosis, and microvascular dysfunction. This study sought to determine the impact of postconditioning – the phenomenon whereby endogenous protection against severe injury is enhanced by subsequent exposure to a mild stressor – on SAH-induced DCI. Methods Adult male C57BL/6 mice were subjected to sham, SAH, or SAH plus isoflurane postconditioning. Neurological outcome was assessed daily via sensorimotor scoring. Contributors to DCI including cerebral vasospasm, microvessel thrombosis, and microvascular dysfunction were measured 3 days later. Isoflurane-induced changes in hypoxia-inducible factor 1alpha (HIF-1α)-dependent genes were assessed via quantitative polymerase chain reaction. HIF-1α was inhibited pharmacologically via 2-methoxyestradiol (2ME2) or genetically via endothelial cell HIF-1α-null mice (EC-HIF-1α-null). All experiments were performed in a randomized and blinded fashion. Results Isoflurane postconditioning initiated at clinically relevant time points after SAH significantly reduced cerebral vasospasm, microvessel thrombosis, microvascular dysfunction, and neurological deficits in wild-type (WT) mice. Isoflurane modulated HIF-1α-dependent genes – changes that were abolished in 2ME2-treated WT mice and EC-HIF-1α-null mice. Isoflurane-induced DCI protection was attenuated in 2ME2-treated WT mice and EC-HIF-1α-null mice. Interpretation Isoflurane postconditioning provides strong HIF-1α-mediated macro- and microvascular protection in SAH, leading to improved neurological outcome. These results implicate cerebral vessels as a key target for the brain protection afforded by isoflurane postconditioning, and HIF-1α as a critical mediator of this vascular protection. They also identify isoflurane postconditioning as a promising novel

  2. High glucose induced nuclear factor kappa B mediated inhibition of endothelial cell migration.

    PubMed

    Hamuro, Masao; Polan, Jodie; Natarajan, Mohan; Mohan, Sumathy

    2002-06-01

    Delayed wound healing and accelerated atherosclerosis are common vascular complications of diabetes mellitus. Although elevated blood glucose level is the major contributing factor, mechanisms that mediate these complications are not clearly understood. In the present study, we have demonstrated that elevated glucose inhibits endothelial cell migration, thereby delaying wound healing. Our results clearly indicated that high glucose (10 or 30 mM) induced activation of nuclear factor kappa B (NF-kappaB) inhibited endothelial cell migration (P<0.05). High glucose induced NF-kappaB DNA binding activity may mediate this inhibition of migration by regulating intracellular nitric oxide. In vitro wound healing model in human aortic endothelial cells (HAEC) were used to evaluate cell migration under the influence of high glucose. The migration inhibited by high glucose was restored by NF-kappaB inhibitors (including E3-4-methylphenyl sulfonyl-2-propenenitrile, N-tosyl-Lys-chloromethylketone (TLCK), or over-expression of inhibitor subunit of kappaB) and endothelial nitric oxide synthase inhibitors (N-methyl-L-arginine (L-NMMA); and Nomega-nitro-L-arginine methyl ester (L-NAME)). Furthermore, NF-kappaB inhibitors attenuated high glucose induced eNOS expression and intracellular nitric oxide (NO) production. Cytoskeletal immunofluorescence staining confirmed differences in actin distribution in HAEC incubated in high glucose in the presence or absence of NF-kappaB and NO inhibitors, explaining the differences observed in migration. In summary, our results for the first time suggest therapeutic strategies involving inhibition of NF-kappaB activation induced by high glucose, which may improve wound healing and help avoid some of the vascular complications of diabetes.

  3. 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.

  4. Coagulation-induced shedding of platelet glycoprotein VI mediated by factor Xa.

    PubMed

    Al-Tamimi, Mohammad; Grigoriadis, George; Tran, Huy; Paul, Eldho; Servadei, Patricia; Berndt, Michael C; Gardiner, Elizabeth E; Andrews, Robert K

    2011-04-01

    This study evaluated shedding of the platelet collagen receptor, glycoprotein VI (GPVI) in human plasma. Collagen or other ligands induce metalloproteinase-mediated GPVI ectodomain shedding, generating approximately 55-kDa soluble GPVI (sGPVI) and approximately 10-kDa platelet-associated fragments. In the absence of GPVI ligands, coagulation of platelet-rich plasma from healthy persons induced GPVI shedding, independent of added tissue factor, but inhibitable by metalloproteinase inhibitor, GM6001. Factor Xa (FXa) common to intrinsic and tissue factor-mediated coagulation pathways was critical for sGPVI release because (1) shedding was strongly blocked by the FXa-selective inhibitor rivaroxaban but not FIIa (thrombin) inhibitors dabigatran or hirudin; (2) Russell viper venom that directly activates FX generated sGPVI, with complete inhibition by enoxaparin (inhibits FXa and FIIa) but not hirudin; (3) impaired GPVI shedding during coagulation of washed platelets resuspended in FX-depleted plasma was restored by adding purified FX; and (4) purified FXa induced GM6001-inhibitable GPVI shedding from washed platelets. In 29 patients with disseminated intravascular coagulation, mean plasma sGPVI was 53.9 ng/mL (95% confidence interval, 39.9-72.8 ng/mL) compared with 12.5 ng/mL (95% confidence interval, 9.0-17.3 ng/mL) in thrombocytopenic controls (n = 36, P < .0001), and 14.6 ng/mL (95% confidence interval, 7.9-27.1 ng/mL) in healthy subjects (n = 25, P = .002). In conclusion, coagulation-induced GPVI shedding via FXa down-regulates GPVI under procoagulant conditions. FXa inhibitors have an unexpected role in preventing GPVI down-regulation.

  5. PTEN Phosphorylation and Nuclear Export Mediate Free Fatty Acid-Induced Oxidative Stress

    PubMed Central

    Wu, Yong; Zhou, Hillary; Wu, Ke; Lee, Sangkyu; Li, Ruijin

    2014-01-01

    Abstract Aim: Oxidative stress induced by free fatty acids (FFA) contributes to metabolic syndrome-associated development of cardiovascular diseases, yet molecular mechanisms remain poorly understood. This study aimed at establishing whether phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and its subcellular location play a role in FFA-induced endothelial oxidative stress. Results: Exposing human endothelial cells (ECs) with FFA activated mammalian target of rapamycin (mTOR)/S6K pathway, and upon activation, S6K directly phosphorylated PTEN at S380. Phosphorylation of PTEN increased its interaction with its deubiquitinase USP7 in the nucleus, leading to PTEN deubiquitination and nuclear export. The reduction of PTEN in the nucleus, in turn, decreased p53 acetylation and transcription, reduced the expression of the p53 target gene glutathione peroxidase-1 (GPX1), resulting in reactive oxygen species (ROS) accumulation and endothelial damage. Finally, C57BL/6J mice fed with high-fat atherogenic diet (HFAD) showed PTEN nuclear export, decreased p53 and GPX1 protein expressions, elevated levels of ROS, and significant lesions in aortas. Importantly, inhibition of mTOR or S6K effectively blocked these effects, suggesting that mTOR/S6K pathway mediates HFAD-induced oxidative stress and vascular damage via PTEN/p53/GPX1 inhibition in vivo. Innovation: Our study demonstrated for the first time that S6K directly phosphorylated PTEN at S380 under high FFA conditions, and this phosphorylation mediated FFA-induced endothelial oxidative stress. Furthermore, we showed that S380 phosphorylation affected PTEN monoubiquitination and nuclear localization, providing the first example of coordinated regulation of PTEN nuclear localization via phosphorylation and ubiquitination. Conclusion: Our studies provide a novel mechanism by which hyperlipidemia causes vascular oxidative damage through the phosphorylation of PTEN, blocking of PTEN nuclear function, and inhibition

  6. 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

  7. 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

  8. 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

  9. 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

  10. 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

  11. Coagulation-induced shedding of platelet glycoprotein VI mediated by factor Xa.

    PubMed

    Al-Tamimi, Mohammad; Grigoriadis, George; Tran, Huy; Paul, Eldho; Servadei, Patricia; Berndt, Michael C; Gardiner, Elizabeth E; Andrews, Robert K

    2011-04-01

    This study evaluated shedding of the platelet collagen receptor, glycoprotein VI (GPVI) in human plasma. Collagen or other ligands induce metalloproteinase-mediated GPVI ectodomain shedding, generating approximately 55-kDa soluble GPVI (sGPVI) and approximately 10-kDa platelet-associated fragments. In the absence of GPVI ligands, coagulation of platelet-rich plasma from healthy persons induced GPVI shedding, independent of added tissue factor, but inhibitable by metalloproteinase inhibitor, GM6001. Factor Xa (FXa) common to intrinsic and tissue factor-mediated coagulation pathways was critical for sGPVI release because (1) shedding was strongly blocked by the FXa-selective inhibitor rivaroxaban but not FIIa (thrombin) inhibitors dabigatran or hirudin; (2) Russell viper venom that directly activates FX generated sGPVI, with complete inhibition by enoxaparin (inhibits FXa and FIIa) but not hirudin; (3) impaired GPVI shedding during coagulation of washed platelets resuspended in FX-depleted plasma was restored by adding purified FX; and (4) purified FXa induced GM6001-inhibitable GPVI shedding from washed platelets. In 29 patients with disseminated intravascular coagulation, mean plasma sGPVI was 53.9 ng/mL (95% confidence interval, 39.9-72.8 ng/mL) compared with 12.5 ng/mL (95% confidence interval, 9.0-17.3 ng/mL) in thrombocytopenic controls (n = 36, P < .0001), and 14.6 ng/mL (95% confidence interval, 7.9-27.1 ng/mL) in healthy subjects (n = 25, P = .002). In conclusion, coagulation-induced GPVI shedding via FXa down-regulates GPVI under procoagulant conditions. FXa inhibitors have an unexpected role in preventing GPVI down-regulation. PMID:21252089

  12. The CB1 cannabinoid receptor mediates excitotoxicity-induced neural progenitor proliferation and neurogenesis.

    PubMed

    Aguado, Tania; Romero, Eva; Monory, Krisztina; Palazuelos, Javier; Sendtner, Michael; Marsicano, Giovanni; Lutz, Beat; Guzmán, Manuel; Galve-Roperh, Ismael

    2007-08-17

    Endocannabinoids are lipid signaling mediators that exert an important neuromodulatory role and confer neuroprotection in several types of brain injury. Excitotoxicity and stroke can induce neural progenitor (NP) proliferation and differentiation as an attempt of neuroregeneration after damage. Here we investigated the mechanism of hippocampal progenitor cell engagement upon excitotoxicity induced by kainic acid administration and the putative involvement of the CB1 cannabinoid receptor in this process. Adult NPs express kainate receptors that mediate proliferation and neurosphere generation in vitro via CB1 cannabinoid receptors. Similarly, in vivo studies showed that excitotoxicity-induced hippocampal NPs proliferation and neurogenesis are abrogated in CB1-deficient mice and in wild-type mice administered with the selective CB1 antagonist rimonabant (N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-3-pyrazolecarboxamide; SR141716). Kainate stimulation increased basic fibroblast growth factor (bFGF) expression in cultured NPs in a CB1-dependent manner as this response was prevented by rimonabant and mimicked by endocannabinoids. Likewise, in vivo analyses showed that increased hippocampal expression of bFGF, as well as of brain-derived neurotrophic factor and epidermal growth factor, occurs upon excitotoxicity and that CB1 receptor ablation prevents this induction. Moreover, excitotoxicity increased the number of CB1+ bFGF+ cells, and this up-regulation preceded NP proliferation. In summary, our results show the involvement of the CB1 cannabinoid receptor in NP proliferation and neurogenesis induced by excitotoxic injury and support a role for bFGF signaling in this process.

  13. Do induced responses mediate the ecological interactions between the specialist herbivores and phytopathogens of an alpine plant?

    PubMed

    Röder, Gregory; Rahier, Martine; Naisbit, Russell E

    2011-01-01

    Plants are not passive victims of the myriad attackers that rely on them for nutrition. They have a suite of physical and chemical defences, and are even able to take advantage of the enemies of their enemies. These strategies are often only deployed upon attack, so may lead to indirect interactions between herbivores and phytopathogens. In this study we test for induced responses in wild populations of an alpine plant (Adenostyles alliariae) that possesses constitutive chemical defence (pyrrolizidine alkaloids) and specialist natural enemies (two species of leaf beetle, Oreina elongata and Oreina cacaliae, and the phytopathogenic rust Uromyces cacaliae). Plants were induced in the field using chemical elicitors of the jasmonic acid (JA) and salicylic acid (SA) pathways and monitored for one month under natural conditions. There was evidence for induced resistance, with lower probability and later incidence of attack by beetles in JA-induced plants and of rust infection in SA-induced plants. We also demonstrate ecological cross-effects, with reduced fungal attack following JA-induction, and a cost of SA-induction arising from increased beetle attack. As a result, there is the potential for negative indirect effects of the beetles on the rust, while in the field the positive indirect effect of the rust on the beetles appears to be over-ridden by direct effects on plant nutritional quality. Such interactions resulting from induced susceptibility and resistance must be considered if we are to exploit plant defences for crop protection using hormone elicitors or constitutive expression. More generally, the fact that induced defences are even found in species that possess constitutively-expressed chemical defence suggests that they may be ubiquitous in higher plants.

  14. TRIF mediates Toll-like receptor 5-induced signaling in intestinal epithelial cells.

    PubMed

    Choi, Yoon Jeong; Im, Eunok; Chung, Hyo Kyun; Pothoulakis, Charalabos; Rhee, Sang Hoon

    2010-11-26

    Toll-like receptors (TLRs) associate with adaptor molecules (MyD88, Mal/TIRAP, TRAM, and TRIF) to mediate signaling of host-microbial interaction. For instance, TLR4 utilizes the combination of both Mal/TIRAP-MyD88 (MyD88-dependent pathway) and TRAM-TRIF (MyD88-independent pathway). However, TLR5, the specific receptor for flagellin, is known to utilize only MyD88 to elicit inflammatory responses, and an involvement of other adaptor molecules has not been suggested in TLR5-dependent signaling. Here, we found that TRIF is involved in mediating TLR5-induced nuclear factor κB (NFκB) and mitogen-activated protein kinases (MAPKs), specifically JNK1/2 and ERK1/2, activation in intestinal epithelial cells. TLR5 activation by flagellin permits the physical interaction between TLR5 and TRIF in human colonic epithelial cells (NCM460), whereas TLR5 does not interact with TRAM upon flagellin stimulation. Both primary intestinal epithelial cells from TRIF-KO mice and TRIF-silenced NCM460 cells significantly reduced flagellin-induced NFκB (p105 and p65), JNK1/2, and ERK1/2 activation compared with control cells. However, p38 activation by flagellin was preserved in these TRIF-deficient cells. TRIF-KO intestinal epithelial cells exhibited substantially reduced inflammatory cytokine (keratinocyte-derived cytokine, macrophage inflammatory protein 3α, and IL-6) expression upon flagellin, whereas control cells from TRIF-WT mice showed robust cytokine expression by flagellin. Compare with TRIF-WT mice, TRIF-KO mice were resistant to in vivo intestinal inflammatory responses: flagellin-mediated exacerbation of colonic inflammation and dextran sulfate sodium-induced experimental colitis. We conclude that in addition to MyD88, TRIF mediates TLR5-dependent responses and, thereby regulates inflammatory responses elicited by flagellin/TLR5 engagement. Our findings suggest an important role of TRIF in regulating host-microbial communication via TLR5 in the gut epithelium.

  15. Nuclear Membranes ETB Receptors Mediate ET-1-induced Increase of Nuclear Calcium in Human Left Ventricular Endocardial Endothelial Cells.

    PubMed

    Jules, Farah; Avedanian, Levon; Al-Khoury, Johny; Keita, Ramatoulaye; Normand, Alexandre; Bkaily, Ghassan; Jacques, Danielle

    2015-07-01

    In fetal human left ventricular endocardial endothelial cells (EECLs), both plasma membrane (PM) ET(A)R and ET(B)R were reported to mediate ET-1-induced increase of intracellular calcium [Ca](i); however, this effect was mediated by ET(A)R in right EECs (EECRs). In this study, we verified whether, as for the PM, nuclear membranes (NMs) ET-1 receptors activation in EECLs and EECRs induce an increase of nuclear calcium ([Ca](n)) and if this effect is mediated through the same receptor type as in PM. Using a plasmalemma-perforated technique and 3D confocal microscopy, our results showed that, as in PM intact cells, superfusion of nuclei of both cell types with cytosolic ET-1 induced a concentration-dependent sustained increase of [Ca](n). In EECRs, the ET(A)R antagonist prevented the effect of ET-1 on [Ca](n) without affecting EECLs. However, in both cell types, the effect of cytosolic ET-1 on [Ca](n) was prevented by the ETBR antagonist. In conclusion, both NMs' ET(A)R and ET(B)R mediated the effect of cytosolic ET-1 on [Ca](n) in EECRs. In contrast, only NMs' ET(B)R activation mediated the effect of cytosolic ET-1 in EECLs. Hence, the type of NMs' receptors mediating the effect of ET-1 on [Ca](n) are different from those of PM mediating the increase in [Ca](i).

  16. 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

  17. Death-associated protein kinase 2 mediates nocodazole-induced apoptosis through interaction with tubulin.

    PubMed

    Isshiki, Kinuka; Hirase, Taishi; Matsuda, Shinya; Miyamoto, Kenji; Tsuji, Akihiko; Yuasa, Keizo

    Death-associated protein kinase 2 (DAPK2) is a positive regulator of apoptosis. Although we recently reported that 14-3-3 proteins inhibit DAPK2 activity and its subsequent apoptotic effects via binding to DAPK2, the molecular mechanisms underlying the DAPK2-mediated apoptotic pathway remain unclear. Therefore, we attempted to further identify DAPK2-interacting proteins using pull-down assays and mass spectrometry. The microtubule β-tubulin was identified as a novel DAPK2-binding protein in HeLa cells. Pull-down assays revealed that DAPK2 interacted with the α/β-tubulin heterodimer, and that the C-terminal region of DAPK2, which differs from that of other DAPK family members, was sufficient for the association with β-tubulin. Although the microtubule-depolymerizing agent nocodazole induced apoptosis in HeLa cells, the level of apoptosis was significantly decreased in the DAPK2 knockdown cells. Furthermore, we found that treatment with nocodazole resulted in an increased binding of DAPK2 to β-tubulin. These findings indicate that DAPK2 mediates nocodazole-induced apoptosis via binding to tubulin.

  18. 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.

  19. Distributed forebrain sites mediate melatonin-induced short-day responses in Siberian hamsters.

    PubMed

    Leitner, Claudia; Bartness, Timothy J

    2010-07-01

    The pineal hormone melatonin (MEL) is the key initiator in regulating seasonal photoperiodic responses; however, the central sites that mediate short day (SD) winter-like responses, such as testicular regression and decreases in white adipose tissue (WAT) mass, by Siberian hamsters are not precisely known. WAT is innervated by the sympathetic nervous system, and several forebrain sites that are part of the sympathetic nervous system outflow to WAT coexpress MEL(1a) receptor mRNA [e.g. suprachiasmatic nucleus, subzona incerta (SubZi), dorsomedial nucleus of the hypothalamus, nucleus reunions and paraventricular nuclei of the thalamus]. We tested the involvement of these sites in MEL-triggered SD responses. A long duration, SD-like MEL signal was applied site specifically for 5 wk, with sc and third ventricle MEL application serving as positive controls. Whereas SD MEL signals delivered to each of these sites were able to induce testicular regression, all but the paraventricular nuclei of the thalamus also trigger SD-induced decreases in body mass. Third ventricle, sc, suprachiasmatic nucleus, or SubZi MEL application also decreased WAT mass, and only sc and SubZi MEL application decreased food intake. Collectively these data suggest a distributed system of MEL-sensitive brain sites sufficient to mediate these SD responses, the redundancy of which suggests its importance for appropriate seasonal responses critical for overwintering.

  20. Aag DNA Glycosylase Promotes Alkylation-Induced Tissue Damage Mediated by Parp1

    PubMed Central

    Calvo, Jennifer A.; Moroski-Erkul, Catherine A.; Lake, Annabelle; Eichinger, Lindsey W.; Shah, Dharini; Jhun, Iny; Limsirichai, Prajit; Bronson, Roderick T.; Christiani, David C.; Meira, Lisiane B.; Samson, Leona D.

    2013-01-01

    Alkylating agents comprise a major class of front-line cancer chemotherapeutic compounds, and while these agents effectively kill tumor cells, they also damage healthy tissues. Although base excision repair (BER) is essential in repairing DNA alkylation damage, under certain conditions, initiation of BER can be detrimental. Here we illustrate that the alkyladenine DNA glycosylase (AAG) mediates alkylation-induced tissue damage and whole-animal lethality following exposure to alkylating agents. Aag-dependent tissue damage, as observed in cerebellar granule cells, splenocytes, thymocytes, bone marrow cells, pancreatic β-cells, and retinal photoreceptor cells, was detected in wild-type mice, exacerbated in Aag transgenic mice, and completely suppressed in Aag−/− mice. Additional genetic experiments dissected the effects of modulating both BER and Parp1 on alkylation sensitivity in mice and determined that Aag acts upstream of Parp1 in alkylation-induced tissue damage; in fact, cytotoxicity in WT and Aag transgenic mice was abrogated in the absence of Parp1. These results provide in vivo evidence that Aag-initiated BER may play a critical role in determining the side-effects of alkylating agent chemotherapies and that Parp1 plays a crucial role in Aag-mediated tissue damage. PMID:23593019

  1. 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

  2. Ethylene-induced stomatal closure in Arabidopsis occurs via AtrbohF-mediated hydrogen peroxide synthesis.

    PubMed

    Desikan, Radhika; Last, Kathryn; Harrett-Williams, Rhian; Tagliavia, Cecilia; Harter, Klaus; Hooley, Richard; Hancock, John T; Neill, Steven J

    2006-09-01

    Ethylene is a plant hormone that regulates many aspects of growth and development. Despite the well-known association between ethylene and stress signalling, its effects on stomatal movements are largely unexplored. Here, genetic and physiological data are provided that position ethylene into the Arabidopsis guard cell signalling network, and demonstrate a functional link between ethylene and hydrogen peroxide (H(2)O(2)). In wild-type leaves, ethylene induces stomatal closure that is dependent on H(2)O(2) production in guard cells, generated by the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH) oxidase AtrbohF. Ethylene-induced closure is inhibited by the ethylene antagonists 1-MCP and silver. The ethylene receptor mutants etr1-1 and etr1-3 are insensitive to ethylene in terms of stomatal closure and H(2)O(2) production. Stomata of the ethylene signalling ein2-1 and arr2 mutants do not close in response to either ethylene or H(2)O(2) but do generate H(2)O(2) following ethylene challenge. Thus, the data indicate that ethylene and H(2)O(2) signalling in guard cells are mediated by ETR1 via EIN2 and ARR2-dependent pathway(s), and identify AtrbohF as a key mediator of stomatal responses to ethylene.

  3. Stress Induces p38 MAPK-mediated Phosphorylation and Inhibition of Drosha-dependent Cell Survival

    PubMed Central

    Yang, Qian; Li, Wenming; She, Hua; Dou, Juan; Duong, Duc M; Du, Yuhong; Yang, Shao-Hua; Seyfried, Nicholas T.; Fu, Haian; Gao, Guodong; Mao, Zixu

    2015-01-01

    SUMMARY MicroRNAs (miRNAs) regulate the translational potential of their mRNA targets and control many cellular processes. The key step in canonical miRNA biogenesis is the cleavage of the primary transcripts by the nuclear RNase III enzyme Drosha. Emerging evidence suggests that the miRNA biogenic cascade is tightly controlled. However, little is known whether Drosha is regulated. Here we show that Drosha is targeted by stress. Under stress, p38 MAPK directly phosphorylates Drosha at its N-terminus. This reduces its interaction with DiGeorge syndrome critical region 8, and promotes its nuclear export and degradation by calpain. This regulatory mechanism mediates stress-induced inhibition of Drosha function. Reduction of Drosha sensitizes cells to stress and increases death. In contrast, increase in Drosha attenuates stress-induced death. These findings reveal a critical regulatory mechanism by which stress engages p38 MAPK pathway to destabilize Drosha and inhibit Drosha-mediated cellular survival. PMID:25699712

  4. Physical exercise-induced hippocampal neurogenesis and antidepressant effects are mediated by the adipocyte hormone adiponectin.

    PubMed

    Yau, Suk Yu; Li, Ang; Hoo, Ruby L C; Ching, Yick Pang; Christie, Brian R; Lee, Tatia M C; Xu, Aimin; So, Kwok-Fai

    2014-11-01

    Adiponectin (ADN) is an adipocyte-secreted protein with insulin-sensitizing, antidiabetic, antiinflammatory, and antiatherogenic properties. Evidence is also accumulating that ADN has neuroprotective activities, yet the underlying mechanism remains elusive. Here we show that ADN could pass through the blood-brain barrier, and elevating its levels in the brain increased cell proliferation and decreased depression-like behaviors. ADN deficiency did not reduce the basal hippocampal neurogenesis or neuronal differentiation but diminished the effectiveness of exercise in increasing hippocampal neurogenesis. Furthermore, exercise-induced reduction in depression-like behaviors was abrogated in ADN-deficient mice, and this impairment in ADN-deficient mice was accompanied by defective running-induced phosphorylation of AMP-activated protein kinase (AMPK) in the hippocampal tissue. In vitro analyses indicated that ADN itself could increase cell proliferation of both hippocampal progenitor cells and Neuro2a neuroblastoma cells. The neurogenic effects of ADN were mediated by the ADN receptor 1 (ADNR1), because siRNA targeting ADNR1, but not ADNR2, inhibited the capacity of ADN to enhance cell proliferation. These data suggest that adiponectin may play a significant role in mediating the effects of exercise on hippocampal neurogenesis and depression, possibly by activation of the ADNR1/AMPK signaling pathways, and also raise the possibility that adiponectin and its agonists may represent a promising therapeutic treatment for depression.

  5. The lectin ArtinM binds to mast cells inducing cell activation and mediator release.

    PubMed

    Barbosa-Lorenzi, Valéria Cintra; Buranello, Patrícia Andressa de Almeida; Roque-Barreira, Maria Cristina; Jamur, Maria Célia; Oliver, Constance; Pereira-da-Silva, Gabriela

    2011-12-16

    Mast cells are inflammatory cells that respond to signals of innate and adaptive immunity with immediate and delayed release of mediators. ArtinM, a lectin from Artocarpus integrifolia with immunomodulatory activities, is able to induce mast cell activation, but the mechanisms remain unknown. This study sought to further investigate the effects of the lectin on mast cells. We showed that ArtinM binds to mast cells, possibly to the high affinity receptor for immunoglobulin E (IgE) - FcεRI - and/or to IgE bound to FcεRI. Binding of the lectin resulted in protein tyrosine phosphorylation and release of the pre- and newly-formed mediators, β-hexosaminidase and LTB(4) by mast cells, activities that were potentiated in the presence of IgE. ArtinM also induced the activation of the transcription factors NFκB and NFAT, resulting in expression of some of their target genes such as IL-4 and TNF-α. In view of the established significance of mast cells in many immunological and inflammatory reactions, a better understanding of the mechanisms involved in mast cell activation by ArtinM is crucial to the pharmacological application of the lectin.

  6. 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

  7. 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

  8. 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.

  9. Hepatocyte necrosis induced by oxidative stress and IL-1α release mediate carcinogen-induced compensatory proliferation and liver tumorigenesis

    PubMed Central

    Sakurai, Toshiharu; He, Guobin; Matsuzawa, Atsushi; Yu, Guann-Yi; Maeda, Shin; Hardiman, Gary; Karin, Michael

    2009-01-01

    SUMMARY Hepatocyte IκB kinase β (IKKβ) inhibits hepatocarcinogenesis by suppressing accumulation of reactive oxygen species (ROS) and liver damage, whereas JNK1 activation promotes ROS accumulation, liver damage and carcinogenesis. We examined whether hepatocyte p38α, found to inhibit liver carcinogenesis, acts similarly to IKKβ in control of ROS metabolism and cell death. Hepatocyte-specific p38α ablation enhanced ROS accumulation and liver damage, which were prevented upon administration of an antioxidant. In addition to elevated ROS accumulation, hepatocyte death, augmented by loss of either IKKβ or p38α, was associated with release of IL-1α. Inhibition of IL-1α action or ablation of its receptor inhibited carcinogen-induced compensatory proliferation and liver tumorigenesis. IL-1α release by necrotic hepatocytes is therefore an important mediator of liver tumorigenesis. PMID:18691550

  10. The matricellular protein Cyr61 is a key mediator of platelet-derived growth factor-induced cell migration.

    PubMed

    Zhang, Fuqiang; Hao, Feng; An, Dong; Zeng, Linlin; Wang, Yi; Xu, Xuemin; Cui, Mei-Zhen

    2015-03-27

    Platelet-derived growth factor (PDGF), a potent chemoattractant, induces cell migration via the MAPK and PI3K/Akt pathways. However, the downstream mediators are still elusive. In particular, the role of extracellular mediators is largely unknown. In this study, we identified the matricellular protein Cyr61, which is de novo synthesized in response to PDGF stimulation, as the key downstream mediator of the ERK and JNK pathways, independent of the p38 MAPK and AKT pathways, and, thereby, it mediates PDGF-induced smooth muscle cell migration but not proliferation. Our results revealed that, when Cyr61 was newly synthesized by PDGF, it was promptly translocated to the extracellular matrix and physically interacted with the plasma membrane integrins α6β1 and αvβ3. We further demonstrate that Cyr61 and integrins are integral components of the PDGF signaling pathway via an "outside-in" signaling route to activate intracellular focal adhesion kinase (FAK), leading to cell migration. Therefore, this study provides the first evidence that the PDGF-induced endogenous extracellular matrix component Cyr61 is a key mediator in modulating cell migration by connecting intracellular PDGF-ERK and JNK signals with integrin/FAK signaling. Therefore, extracellular Cyr61 convergence with growth factor signaling and integrin/FAK signaling is a new concept of growth factor-induced cell migration. The discovered signaling pathway may represent an important therapeutic target in growth factor-mediated cell migration/invasion-related vascular diseases and tumorigenesis.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. RB mutation and RAS overexpression induce resistance to NK cell-mediated cytotoxicity in glioma cells.

    PubMed

    Orozco-Morales, Mario; Sánchez-García, Francisco Javier; Golán-Cancela, Irene; Hernández-Pedro, Norma; Costoya, Jose A; de la Cruz, Verónica Pérez; Moreno-Jiménez, Sergio; Sotelo, Julio; Pineda, Benjamín

    2015-01-01

    Several theories aim to explain the malignant transformation of cells, including the mutation of tumor suppressors and proto-oncogenes. Deletion of Rb (a tumor suppressor), overexpression of mutated Ras (a proto-oncogene), or both, are sufficient for in vitro gliomagenesis, and these genetic traits are associated with their proliferative capacity. An emerging hallmark of cancer is the ability of tumor cells to evade the immune system. Whether specific mutations are related with this, remains to be analyzed. To address this issue, three transformed glioma cell lines were obtained (Rb(-/-), Ras(V12), and Rb(-/-)/Ras(V12)) by in vitro retroviral transformation of astrocytes, as previously reported. In addition, Ras(V12) and Rb(-/-)/Ras(V12) transformed cells were injected into SCID mice and after tumor growth two stable glioma cell lines were derived. All these cells were characterized in terms of Rb and Ras gene expression, morphology, proliferative capacity, expression of MHC I, Rae1δ, and Rae1αβγδε, mult1, H60a, H60b, H60c, as ligands for NK cell receptors, and their susceptibility to NK cell-mediated cytotoxicity. Our results show that transformation of astrocytes (Rb loss, Ras overexpression, or both) induced phenotypical and functional changes associated with resistance to NK cell-mediated cytotoxicity. Moreover, the transfer of cell lines of transformed astrocytes into SCID mice increased resistance to NK cell-mediated cytotoxicity, thus suggesting that specific changes in a tumor suppressor (Rb) and a proto-oncogene (Ras) are enough to confer resistance to NK cell-mediated cytotoxicity in glioma cells and therefore provide some insight into the ability of tumor cells to evade immune responses.

  16. The Proinflammatory Cytokine High-Mobility Group Box-1 Mediates Retinal Neuropathy Induced by Diabetes

    PubMed Central

    Mairaj Siddiquei, Mohammad; Nawaz, Mohd Imtiaz; Mohammad, Ghulam

    2014-01-01

    To test the hypothesis that increased expression of proinflammatory cytokine high-mobility group box-1 (HMGB1) in epiretinal membranes and vitreous fluid from patients with proliferative diabetic retinopathy and in retinas of diabetic rats plays a pathogenetic role in mediating diabetes-induced retinal neuropathy. Retinas of 1-month diabetic rats and HMGB1 intravitreally injected normal rats were studied using Western blot analysis, RT-PCR and glutamate assay. In addition, we studied the effect of the HMGB1 inhibitor glycyrrhizin on diabetes-induced biochemical changes in the retina. Diabetes and intravitreal injection of HMGB1 in normal rats induced significant upregulation of HMGB1 protein and mRNA, activated extracellular signal-regulated kinase 1 and 2 (ERK1/2), cleaved caspase-3 and glutamate; and significant downregulation of synaptophysin, tyrosine hydroxylase, glutamine synthetase, and glyoxalase 1. Constant glycyrrhizin intake from the onset of diabetes did not affect the metabolic status of the diabetic rats, but it significantly attenuated diabetes-induced upregulation of HMGB1 protein and mRNA, activated ERK1/2, cleaved caspase-3, and glutamate. In the glycyrrhizin-fed diabetic rats, the decrease in synaptophysin, tyrosine hydroxylase, and glyoxalase 1 caused by diabetes was significantly attenuated. These findings suggest that early retinal neuropathy of diabetes involves upregulated expression of HMGB1 and can be ameliorated by inhibition of HMGB1. PMID:24733965

  17. CRH Engagement of the Locus Coeruleus Noradrenergic System Mediates Stress-Induced Anxiety.

    PubMed

    McCall, Jordan G; Al-Hasani, Ream; Siuda, Edward R; Hong, Daniel Y; Norris, Aaron J; Ford, Christopher P; Bruchas, Michael R

    2015-08-01

    The locus coeruleus noradrenergic (LC-NE) system is one of the first systems engaged following a stressful event. While numerous groups have demonstrated that LC-NE neurons are activated by many different stressors, the underlying neural circuitry and the role of this activity in generating stress-induced anxiety has not been elucidated. Using a combination of in vivo chemogenetics, optogenetics, and retrograde tracing, we determine that increased tonic activity of the LC-NE system is necessary and sufficient for stress-induced anxiety and aversion. Selective inhibition of LC-NE neurons during stress prevents subsequent anxiety-like behavior. Exogenously increasing tonic, but not phasic, activity of LC-NE neurons is alone sufficient for anxiety-like and aversive behavior. Furthermore, endogenous corticotropin-releasing hormone(+) (CRH(+)) LC inputs from the amygdala increase tonic LC activity, inducing anxiety-like behaviors. These studies position the LC-NE system as a critical mediator of acute stress-induced anxiety and offer a potential intervention for preventing stress-related affective disorders.

  18. 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

  19. 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

  20. Peripheral tackykinin and excitatory amino acid receptors mediate hyperalgesia induced by Phoneutria nigriventer venom.

    PubMed

    Zanchet, Eliane Maria; Cury, Yara

    2003-04-25

    The generation of hyperalgesia by Phoneutria nigriventer venom was investigated in rats using the paw pressure test, through the intraplantar injection of the venom. Hyperalgesia was significantly inhibited by N-[2-(4-chlorophenyl) ethyl]-1,3,4,5-tetrahydro-7,8-dihydroxy-2H-2-benzazepine-2-carbothioamide (capsazepine), a vanilloid receptor antagonist, by the local administration of pGlu-Ala-Asp-Pro-Asn-Lys-Phe-Tyr-Pro (spiro-gamma-lactam) Leu-Trp-NH(2) (GR82334) or of Phenyl-CO-Ala-Ala-D-Trp-Phe-D-Pro-Pro-Nle-NH(2) (GR94800), inhibitors of tachykinin NK(1) and NK(2) receptors, respectively, or by the local injection of dizocilpine (MK 801), (+/-)-2-amino-5-phosphonopentanoic acid ((+/-)-AP-5), or 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), antagonists of NMDA and non-NMDA excitatory amino acid receptors. The correlation between hyperalgesia and the inflammatory response induced by the venom was also investigated. The venom-induced edematogenic response was not modified by the pharmacological treatments. These results suggest that hyperalgesia induced by P. nigriventer venom is mediated by stimulation of capsaicin-sensitive neurons, with activation of peripheral tachykinin NK(1) and NK(2) receptors and of both the NMDA and AMPA receptors. Distinct mechanisms are involved in the development of hyperalgesia and edema induced by the venom.

  1. 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.

  2. 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

  3. Rictor/mTORC2 signaling mediates TGFβ1-induced fibroblast activation and kidney fibrosis.

    PubMed

    Li, Jianzhong; Ren, Jiafa; Liu, Xin; Jiang, Lei; He, Weichun; Yuan, Weiping; Yang, Junwei; Dai, Chunsun

    2015-09-01

    The mammalian target of rapamycin (mTOR) was recently identified in two structurally distinct multiprotein complexes: mTORC1 and mTORC2. Previously, we found that Rictor/mTORC2 protects against cisplatin-induced acute kidney injury, but the role and mechanisms for Rictor/mTORC2 in TGFβ1-induced fibroblast activation and kidney fibrosis remains unknown. To study this, we initially treated NRK-49F cells with TGFβ1 and found that TGFβ1 could activate Rictor/mTORC2 signaling in cultured cells. Blocking Rictor/mTORC2 signaling with Rictor or Akt1 small interfering RNAs markedly inhibited TGFβ1-induced fibronection and α-smooth muscle actin expression. Ensuing western blotting or immunostaining results showed that Rictor/mTORC2 signaling was activated in kidney interstitial myofibroblasts from mice with unilateral ureteral obstruction. Next, a mouse model with fibroblast-specific deletion of Rictor was generated. These knockout mice were normal at birth and had no obvious kidney dysfunction or kidney morphological abnormality within 2 months of birth. Compared with control littermates, the kidneys of Rictor knockout mice developed less interstitial extracellular matrix deposition and inflammatory cell infiltration at 1 or 2 weeks after ureteral obstruction. Thus our study suggests that Rictor/mTORC2 signaling activation mediates TGFβ1-induced fibroblast activation and contributes to the development of kidney fibrosis. This may provide a therapeutic target for chronic kidney diseases.

  4. 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.

  5. Rictor/mTORC2 signaling mediates TGFβ1-induced fibroblast activation and kidney fibrosis

    PubMed Central

    Li, Jianzhong; Ren, Jiafa; Liu, Xin; Jiang, Lei; He, Weichun; Yuan, Weiping; Yang, Junwei; Dai, Chunsun

    2015-01-01

    The mammalian target of rapamycin (mTOR) was recently identified in two structurally distinct multiprotein complexes: mTORC1 and mTORC2. Previously, we found that Rictor/mTORC2 protects against cisplatin-induced acute kidney injury, but the role and mechanisms for Rictor/mTORC2 in TGFβ1-induced fibroblast activation and kidney fibrosis remains unknown. To study this, we initially treated NRK-49F cells with TGFβ1 and found that TGFβ1 could activate Rictor/mTORC2 signaling in cultured cells. Blocking Rictor/mTORC2 signaling with Rictor or Akt1 small interfering RNAs markedly inhibited TGFβ1-induced fibronection and α-smooth muscle actin expression. Ensuing western blotting or immunostaining results showed that Rictor/mTORC2 signaling was activated in kidney interstitial myofibroblasts from mice with unilateral ureteral obstruction. Next, a mouse model with fibroblast-specific deletion of Rictor was generated. These knockout mice were normal at birth and had no obvious kidney dysfunction or kidney morphological abnormality within 2 months of birth. Compared with control littermates, the kidneys of Rictor knockout mice developed less interstitial extracellular matrix deposition and inflammatory cell infiltration at 1 or 2 weeks after ureteral obstruction. Thus our study suggests that Rictor/mTORC2 signaling activation mediates TGFβ1-induced fibroblast activation and contributes to the development of kidney fibrosis. This may provide a therapeutic target for chronic kidney diseases. PMID:25970154

  6. Hemeoxygenase-1 Mediates an Adaptive Response to Spermidine-Induced Cell Death in Human Endothelial Cells

    PubMed Central

    Yang, Hana; Lee, Seung Eun; Kim, Gun-Dong; Park, Hye Rim; Park, Yong Seek

    2013-01-01

    Spermidine (SPD) is a ubiquitous polycation that is commonly distributed in living organisms. Intracellular levels of SPD are tightly regulated, and SPD controls cell proliferation and death. However, SPD undergoes oxidation in the presence of serum, producing aldehydes, hydrogen peroxide, and ammonia, which exert cytotoxic effect on cells. Hemeoxygenase-1 (HO-1) is thought to have a protective effect against oxidative stress. Upregulation of HO-1 in endothelial cells is considered to be beneficial in the cardiovascular disease. In the present study, we demonstrate that the ubiquitous polyamine, SPD, induces HO-1 in human umbilical vein endothelial cells (HUVECs). SPD-induced HO-1 expression was examined by Western blot and reverse transcription-polymerase chain reaction (RT-PCR). Involvement of reactive oxygen species, serum amine oxidase, PI3K/Akt signaling pathway, and transcription factor Nrf2 in the induction of HO-1 by SPD was also investigated. Furthermore, small interfering RNA knockdown of Nrf2 or HO-1 and treatment with the specific HO-1 inhibitor ZnPP exhibited a noteworthy increase of death of SPD-stimulated HUVECs. In conclusion, these results suggest that SPD induces PI3K/Akt-Nrf2-mediated HO-1 expression in human endothelial cells, which may have a role in cytoprotection of the cells against oxidative stress-induced death. PMID:23983896

  7. induces PUMA activation: a new mechanism for Aβ-mediated neuronal apoptosis.

    PubMed

    Feng, Jie; Meng, Chengbo; Xing, Da

    2015-02-01

    p53 upregulated modulator of apoptosis (PUMA) is a promising tumor therapy target because it elicits apoptosis and profound sensitivity to radiation and chemotherapy. However, inhibition of PUMA may be beneficial for curbing excessive apoptosis associated with neurodegenerative disorders. Alzheimer's disease (AD) is a representative neurodegenerative disease in which amyloid-β (Aβ) deposition causes neurotoxicity. The regulation of PUMA during Aβ-induced neuronal apoptosis remains poorly understood. Here, we reported that PUMA expression was significantly increased in the hippocampus of transgenic mice models of AD and hippocampal neurons in response to Aβ. PUMA knockdown protected the neurons against Aβ-induced apoptosis. Furthermore, besides p53, PUMA transactivation was also regulated by forkhead box O3a through p53-independent manner following Aβ treatment. Notably, PUMA contributed to neuronal apoptosis through competitive binding of apoptosis repressor with caspase recruitment domain to activate caspase-8 that cleaved Bid into tBid to accelerate Bax mitochondrial translocation, revealing a novel pathway of Bax activation by PUMA to mediate Aβ-induced neuronal apoptosis. Together, we demonstrated that PUMA activation involved in Aβ-induced apoptosis, representing a drug target to antagonize AD progression.

  8. NLRP3 inflammasome mediates contrast media-induced acute kidney injury by regulating cell apoptosis

    PubMed Central

    Shen, Jianxiao; Wang, Ling; Jiang, Na; Mou, Shan; Zhang, Minfang; Gu, Leyi; Shao, Xinghua; Wang, Qin; Qi, Chaojun; Li, Shu; Wang, Wanpeng; Che, Xiajing; Ni, Zhaohui

    2016-01-01

    Iodinated contrast media serves as a direct causative factor of acute kidney injury (AKI) and is involved in the progression of cellular dysfunction and apoptosis. Emerging evidence indicates that NLRP3 inflammasome triggers inflammation, apoptosis and tissue injury during AKI. Nevertheless, the underlying renoprotection mechanism of NLRP3 inflammasome against contrast-induced AKI (CI-AKI) was still uncertain. This study investigated the role of NLRP3 inflammasome in CI-AKI both in vitro and in vivo. In HK-2 cells and unilateral nephrectomy model, NLRP3 and NLRP3 inflammasome member ASC were significantly augmented with the treatment of contrast media. Moreover, genetic disruption of NLRP3 notably reversed contrast-induced expression of apoptosis related proteins and secretion of proinflammatory factors, similarly to the effects of ASC deletion. Consistent with above results, absence of NLRP3 in mice undergoing unilateral nephrectomy also protected against contrast media-induced renal cells phenotypic alteration and cell apoptosis via modulating expression level of apoptotic proteins. Collectively, we demonstrated that NLRP3 inflammasome mediated CI-AKI through modulating the apoptotic pathway, which provided a potential therapeutic target for the treatment of contrast media induced acute kidney injury. PMID:27721494

  9. CRH engagement of the locus coeruleus noradrenergic system mediates stress-induced anxiety

    PubMed Central

    McCall, Jordan G.; Al-Hasani, Ream; Siuda, Edward R.; Hong, Daniel Y.; Norris, Aaron J.; Ford, Christopher P.; Bruchas, Michael R.

    2015-01-01

    Summary The locus coeruleus noradrenergic (LC-NE) system is one of the first systems engaged following a stressful event. While numerous groups have demonstrated that LC-NE neurons are activated by many different stressors, the underlying neural circuitry and the role of this activity in generating stress-induced anxiety has not been elucidated. Using a combination of in vivo chemogenetics, optogenetics, and retrograde tracing we determine that increased tonic activity of the LC-NE system is necessary and sufficient for stress-induced anxiety and aversion. Selective inhibition of LC-NE neurons during stress prevents subsequent anxiety-like behavior. Exogenously increasing tonic, but not phasic, activity of LC-NE neurons is alone sufficient for anxiety-like and aversive behavior. Furthermore, endogenous corticotropin releasing hormone+ (CRH+) LC inputs from the amygdala increase tonic LC activity, inducing anxiety-like behaviors. These studies position the LC-NE system as a critical mediator of acute stress-induced anxiety and offer a potential intervention for preventing stress-related affective disorders. PMID:26212712

  10. Up-regulated Smad5 mediates apoptosis of gastric epithelial cells induced by Helicobacter pylori infection.

    PubMed

    Nagasako, Tomokazu; Sugiyama, Toshiro; Mizushima, Takuji; Miura, Yosuke; Kato, Mototsugu; Asaka, Masahiro

    2003-02-14

    The gastric pathogen Helicobacter pylori activates epithelial cell signaling pathways, and its infection induces changes in the expression of several genes in infected human gastric tissues. Recent studies have indicated that the ability of H. pylori to regulate epithelial cell responses depends on the presence of an intact cag pathogenicity island (cagPAI). We investigated altered mRNA expression of gastric epithelial cells after infection with H. pylori, both cagPAI-positive and cagPAI-negative strains, by cDNA microarray, reverse transcription PCR, and Northern blot analysis. Our results indicated that cagPAI-positive H. pylori strains (ATCC 43504 and clinical isolated strains) significantly activated Smad5 mRNA expression of human gastric epithelial cells (AGS, KATOIII, MKN28, and MKN45). We further examined whether the up-regulated Smad5 was related to apoptosis of gastric epithelial cells induced by H. pylori. Smad5 RNA interference completely inhibited H. pylori-induced apoptosis. These results suggest that Smad5 is up-regulated in gastric epithelial cells through the presence of cagPAI of H. pylori and that Smad5 mediates apoptosis of gastric epithelial cells induced by H. pylori infection. PMID:12473652

  11. 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.

  12. 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

  13. 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

  14. Bushen Zhuangjin decoction inhibits TM-induced chondrocyte apoptosis mediated by endoplasmic reticulum stress.

    PubMed

    Lin, Pingdong; Weng, Xiaping; Liu, Fayuan; Ma, Yuhuan; Chen, Houhuang; Shao, Xiang; Zheng, Wenwei; Liu, Xianxiang; Ye, Hongzhi; Li, Xihai

    2015-12-01

    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

  15. 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

  16. SIGNR1-mediated phagocytosis, but not SIGNR1-mediated endocytosis or cell adhesion, suppresses LPS-induced secretion of IL-6 from murine macrophages.

    PubMed

    Kawauchi, Yoko; Takagi, Hideaki; Hanafusa, Kei; Kono, Mirei; Yamatani, Minami; Kojima, Naoya

    2015-01-01

    C-type lectin receptors (CLRs) serve as phagocytosis receptors for pathogens and also function as adhesion molecules and in the recognition and endocytosis of glycosylated self-antigens. In the present study, we demonstrated that phagocytosis mediated by a mouse mannose-binding CLR, SIGNR1 significantly suppressed the LPS-induced secretion of the specific pro-inflammatory cytokines from the resident peritoneal macrophages and the mouse macrophage-like cells that express SIGNR1 (RAW-SIGNR1). LPS-induced secretion of IL-6 from peritoneal macrophages suppressed in response to uptake of oligomannose-coated liposomes (OMLs), and the suppression was partly inhibited by treatment with an anti-SIGNR1 antibody. LPS-induced secretion of IL-6 from RAW-SIGNR1 cells was also clearly inhibited by treatment of the cells with OMLs >0.4μm in diameter, but treatment with OMLs <0.4μm in diameter did not affect the IL-6 secretion. In contrast, LPS-induced TNF-α secretion from the cells was not affected on treatment of the cells with OMLs. Suppression of the IL-6 secretion was not observed following treatment with oligomannose-containing soluble polymers or when cells were bound to an oligomannose-coated solid phase. Phagocytosis of oligomannose-coated liposomes did not interfere with the transcription of IL-6 mRNA, but did affect IL-6 mRNA stability, leading to suppression of IL-6 secretion. Interestingly, treatment of the cells with Ly290042, a PI3 kinase inhibitor, partly blocked the suppression of LPS-induced secretion of IL-6 by OML. Thus, we conclude that SIGNR1-mediated phagocytosis but not SIGNR1-mediated endocytosis and cell adhesion, suppresses the TLR4-mediated production of specific proinflammatory cytokines via PI3 kinase signaling.

  17. Pseudomonas-derived ceramidase induces production of inflammatory mediators from human keratinocytes via sphingosine-1-phosphate.

    PubMed

    Oizumi, Ami; Nakayama, Hitoshi; Okino, Nozomu; Iwahara, Chihiro; Kina, Katsunari; Matsumoto, Ryo; Ogawa, Hideoki; Takamori, Kenji; Ito, Makoto; Suga, Yasushi; Iwabuchi, Kazuhisa

    2014-01-01

    Ceramide is important for water retention and permeability barrier functions in the stratum corneum, and plays a key role in the pathogenesis of atopic dermatitis (AD). A Pseudomonas aeruginosa-derived neutral ceramidase (PaCDase) isolated from a patient with AD was shown to effectively degrade ceramide in the presence of Staphylococcus aureus-derived lipids or neutral detergents. However, the effect of ceramide metabolites on the functions of differentiating keratinocytes is poorly understood. We found that the ceramide metabolite sphingosine-1-phosphate (S1P) stimulated the production of inflammatory mediators such as TNF-α and IL-8 from three-dimensionally cultured human primary keratinocytes (termed "3D keratinocytes"), which form a stratum corneum. PaCDase alone did not affect TNF-α gene expression in 3D keratinocytes. In the presence of the detergent Triton X-100, which damages stratum corneum structure, PaCDase, but not heat-inactivated PaCDase or PaCDase-inactive mutant, induced the production of TNF-α, endothelin-1, and IL-8, indicating that this production was dependent on ceramidase activity. Among various ceramide metabolites, sphingosine and S1P enhanced the gene expression of TNF-α, endothelin-1, and IL-8. The PaCDase-enhanced expression of these genes was inhibited by a sphingosine kinase inhibitor and by an S1P receptor antagonist VPC 23019. The TNF-α-binding antibody infliximab suppressed the PaCDase-induced upregulation of IL-8, but not TNF-α, mRNA. PaCDase induced NF-κB p65 phosphorylation. The NF-κB inhibitor curcumin significantly inhibited PaCDase-induced expression of IL-8 and endothelin-1. VPC 23019 and infliximab inhibited PaCDase-induced NF-κB p65 phosphorylation and reduction in the protein level of the NF-κB inhibitor IκBα. Collectively, these findings suggest that (i) 3D keratinocytes produce S1P from sphingosine, which is produced through the hydrolysis of ceramide by PaCDase, (ii) S1P induces the production of TNF-α via S

  18. Phosphorylated endothelial nitric oxide synthase mediates vascular endothelial growth factor-induced penile erection.

    PubMed

    Musicki, Biljana; Palese, Michael A; Crone, Julie K; Burnett, Arthur L

    2004-02-01

    The objective of the present study was to evaluate whether vascular endothelial growth factor (VEGF)-induced penile erection is mediated by activation of endothelial nitric oxide synthase (eNOS) through its phosphorylation. We assessed the role of constitutively activated eNOS in VEGF-induced penile erection using wild-type (WT) and eNOS-knockout (eNOS(-/-)) mice with and without vasculogenic erectile dysfunction. Adult WT and eNOS(-/-) mice were subjected to sham operation or bilateral castration to induce vasculogenic erectile dysfunction. At the time of surgery, animals were injected intracavernosally with a replication-deficient adenovirus expressing human VEGF145 (10(9) particle units) or with empty virus (Ad.Null). After 7 days, erectile function was assessed in response to cavernous nerve electrical stimulation. Total and phosphorylated protein kinase B (Akt) as well as total and phosphorylated eNOS were quantitatively assessed in mice penes using Western immunoblot and immunohistochemistry. In intact WT mice, VEGF145 significantly increased erectile responses, and in WT mice after castration, it completely recovered penile erection. However, VEGF145 failed to increase erectile responses in intact eNOS(-/-) mice and only partially recovered erectile function in castrated eNOS(-/-) mice. In addition, VEGF145 significantly increased phosphorylation of eNOS at Serine 1177 by approximately 2-fold in penes of both intact and castrated WT mice. The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation. PMID:14522830

  19. Copper oxide nanoparticles induced mitochondria mediated apoptosis in human hepatocarcinoma cells.

    PubMed

    Siddiqui, Maqsood A; Alhadlaq, Hisham A; Ahmad, Javed; Al-Khedhairy, Abdulaziz A; Musarrat, Javed; Ahamed, Maqusood

    2013-01-01

    Copper oxide nanoparticles (CuO NPs) are heavily utilized in semiconductor devices, gas sensor, batteries, solar energy converter, microelectronics and heat transfer fluids. It has been reported that liver is one of the target organs for nanoparticles after they gain entry into the body through any of the possible routes. Recent studies have shown cytotoxic response of CuO NPs in liver cells. However, the underlying mechanism of apoptosis in liver cells due to CuO NPs exposure is largely lacking. We explored the possible mechanisms of apoptosis induced by CuO NPs in human hepatocellular carcinoma HepG2 cells. Prepared CuO NPs were spherical in shape with a smooth surface and had an average diameter of 22 nm. CuO NPs (concentration range 2-50 µg/ml) were found to induce cytotoxicity in HepG2 cells in dose-dependent manner, which was likely to be mediated through reactive oxygen species generation and oxidative stress. Tumor suppressor gene p53 and apoptotic gene caspase-3 were up-regulated due to CuO NPs exposure. Decrease in mitochondrial membrane potential with a concomitant increase in the gene expression of bax/bcl2 ratio suggested that mitochondria mediated pathway involved in CuO NPs induced apoptosis. This study has provided valuable insights into the possible mechanism of apoptosis caused by CuO NPs at in vitro level. Underlying mechanism(s) of apoptosis due to CuO NPs exposure should be further invested at in vivo level. PMID:23940521

  20. 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.

  1. 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

  2. Does the histaminergic system mediate bombesin/GRP-induced suppression of food intake?

    PubMed

    Merali, Z; Banks, K

    1994-12-01

    Bombesin (BN) and its mammalian homologue, gastrin-releasing peptide (GRP), are potent satiety agents and have been implicated in the physiological regulation of food intake. The mechanism(s) of action of this effect remains unclear. There is a functional and anatomic overlap between histamine and BN in relationship to feeding, which led us to hypothesize that BN may mediate its satiety effects through activation of the histaminergic system. To assess this contention, we examined the effects of R-alpha-methylhistamine (alpha-MH) and Imetit, selective H3-receptor agonists that inhibit the release and synthesis of histamine, on BN- or cholecystokinin (CCK)-induced satiety. In this report we present the first evidence for the role of histamine H3 receptors in the mediation of BN-elicited satiety. During the first hour of the 4-h daily feeding session, BN reduced food intake by > 50% relative to the control condition; this suppression was blocked by prior treatment with the H3-receptor agonist, alpha-MH. This blockade of BN-induced satiety was dose related and selective to BN as alpha-MH failed to attenuate sulfated CCK-8-induced satiety. When alpha-MH was administered alone, it failed to significantly affect food intake. The specificity of this effect was further supported by the demonstration that another H3 agonist, Imetit, was also able to block the feeding-suppressant effects of BN. Furthermore, thioperamide, an H3-receptor antagonist, blocked these effects of Imetit.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. 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

  4. Phosphorylated endothelial nitric oxide synthase mediates vascular endothelial growth factor-induced penile erection.

    PubMed

    Musicki, Biljana; Palese, Michael A; Crone, Julie K; Burnett, Arthur L

    2004-02-01

    The objective of the present study was to evaluate whether vascular endothelial growth factor (VEGF)-induced penile erection is mediated by activation of endothelial nitric oxide synthase (eNOS) through its phosphorylation. We assessed the role of constitutively activated eNOS in VEGF-induced penile erection using wild-type (WT) and eNOS-knockout (eNOS(-/-)) mice with and without vasculogenic erectile dysfunction. Adult WT and eNOS(-/-) mice were subjected to sham operation or bilateral castration to induce vasculogenic erectile dysfunction. At the time of surgery, animals were injected intracavernosally with a replication-deficient adenovirus expressing human VEGF145 (10(9) particle units) or with empty virus (Ad.Null). After 7 days, erectile function was assessed in response to cavernous nerve electrical stimulation. Total and phosphorylated protein kinase B (Akt) as well as total and phosphorylated eNOS were quantitatively assessed in mice penes using Western immunoblot and immunohistochemistry. In intact WT mice, VEGF145 significantly increased erectile responses, and in WT mice after castration, it completely recovered penile erection. However, VEGF145 failed to increase erectile responses in intact eNOS(-/-) mice and only partially recovered erectile function in castrated eNOS(-/-) mice. In addition, VEGF145 significantly increased phosphorylation of eNOS at Serine 1177 by approximately 2-fold in penes of both intact and castrated WT mice. The data provide a molecular explanation for VEGF stimulatory effect on penile erection, which involves phosphorylated eNOS (Serine 1177) mediation.

  5. Adiponectin mediates cardioprotection in oxidative stress-induced cardiac myocyte remodeling

    PubMed Central

    Essick, Eric E.; Ouchi, Noriyuki; Wilson, Richard M.; Ohashi, Koji; Ghobrial, Joanna; Shibata, Rei; Pimentel, David R.

    2011-01-01

    Reactive oxygen species (ROS) induce matrix metalloproteinase (MMP) activity that mediates hypertrophy and cardiac remodeling. Adiponectin (APN), an adipokine, modulates cardiac hypertrophy, but it is unknown if APN inhibits ROS-induced cardiomyocyte remodeling. We tested the hypothesis that APN ameliorates ROS-induced cardiomyocyte remodeling and investigated the mechanisms involved. Cultured adult rat ventricular myocytes (ARVM) were pretreated with recombinant APN (30 μg/ml, 18 h) followed by exposure to physiologic concentrations of H2O2 (1–200 μM). ARVM hypertrophy was measured by [3H]leucine incorporation and atrial natriuretic factor (ANF) and brain natriuretic peptide (BNP) gene expression by RT-PCR. MMP activity was assessed by in-gel zymography. ROS was induced with angiotensin (ANG)-II (3.2 mg·kg−1·day−1 for 14 days) in wild-type (WT) and APN-deficient (APN-KO) mice. Myocardial MMPs, tissue inhibitors of MMPs (TIMPs), p-AMPK, and p-ERK protein expression were determined. APN significantly decreased H2O2-induced cardiomyocyte hypertrophy by decreasing total protein, protein synthesis, ANF, and BNP expression. H2O2-induced MMP-9 and MMP-2 activities were also significantly diminished by APN. APN significantly increased p-AMPK in both nonstimulated and H2O2-treated ARVM. H2O2-induced p-ERK activity and NF-κB activity were both abrogated by APN pretreatment. ANG II significantly decreased myocardial p-AMPK and increased p-ERK expression in vivo in APN-KO vs. WT mice. ANG II infusion enhanced cardiac fibrosis and MMP-2-to-TIMP-2 and MMP-9-to-TIMP-1 ratios in APN-KO vs. WT mice. Thus APN inhibits ROS-induced cardiomyocyte remodeling by activating AMPK and inhibiting ERK signaling and NF-κB activity. Its effects on ROS and ultimately on MMP expression define the protective role of APN against ROS-induced cardiac remodeling. PMID:21666115

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. The hippocampus mediates glucocorticoid-induced impairment of spatial memory retrieval: Dependence on the basolateral amygdala

    PubMed Central

    Roozendaal, Benno; Griffith, Qyana K.; Buranday, Jason; de Quervain, Dominique J.-F.; McGaugh, James L.

    2003-01-01

    Previous studies have indicated that stress-activated glucocorticoid hormones induce temporary memory retrieval impairment. The present study examined whether adrenal steroid receptors in the hippocampus mediate such glucocorticoid effects on spatial memory retrieval. The specific glucocorticoid receptor (GR) agonist 11β, 17β-dihydroxy-6,21-dimethyl-17α-pregna-4,6-trien-20yn-3-one (RU 28362; 5 or 15 ng) infused into the hippocampus of male Sprague–Dawley rats 60 min before water-maze retention testing, 24 h after training, dose-dependently impaired probe-trial retention performance, as assessed both by time spent in the training quadrant and initial latency to cross the platform location. The GR agonist did not affect circulating corticosterone levels immediately after the probe trial, indicating that RU 28362 infusions did not influence retention by altering glucocorticoid feedback mechanisms. As infusions of the GR agonist into the hippocampus 60 min before training did not influence water-maze acquisition or immediate recall, the findings indicated that the GR agonist-induced retention impairment was induced selectively by an influence on information retrieval. In contrast, pretest infusions of the GR agonist administered into the basolateral complex of the amygdala (BLA; 2 or 6 ng) did not alter retention performance in the water maze. However, N-methyl-d-aspartate-induced lesions of the BLA, made 1 week before training, blocked the memory retrieval impairment induced by intrahippocampal infusions of RU 28362 given 60 min before the retention test. These findings indicate that the effects of glucocorticoids on retrieval of long-term spatial memory depend on the hippocampus and, additionally, that neuronal input from the BLA is critical in enabling hippocampal glucocorticoid effects on memory retrieval. PMID:12538851

  11. Amygdala opioid receptors mediate the electroacupuncture-induced deterioration of sleep disruptions in epilepsy rats

    PubMed Central

    2013-01-01

    Background Clinical and experimental evidence demonstrates that sleep and epilepsy reciprocally affect each other. Previous studies indicated that epilepsy alters sleep homeostasis; in contrast, sleep disturbance deteriorates epilepsy. If a therapy possesses both epilepsy suppression and sleep improvement, it would be the priority choice for seizure control. Effects of acupuncture of Feng-Chi (GB20) acupoints on epilepsy suppression and insomnia treatment have been documented in the ancient Chinese literature, Lingshu Jing (Classic of the Miraculous Pivot). Therefore, this study was designed to investigate the effect of electroacupuncture (EA) stimulation of bilateral Feng-Chi acupoints on sleep disruptions in rats with focal epilepsy. Results Our result indicates that administration of pilocarpine into the left central nucleus of amygdala (CeA) induced focal epilepsy and decreased both rapid eye movement (REM) sleep and non-REM (NREM) sleep. High-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints, in which a 30-min EA stimulation was performed before the dark period of the light:dark cycle in three consecutive days, further deteriorated pilocarpine-induced sleep disruptions. The EA-induced exacerbation of sleep disruption was blocked by microinjection of naloxone, μ- (naloxonazine), κ- (nor-binaltorphimine) or δ-receptor antagonists (natrindole) into the CeA, suggesting the involvement of amygdaloid opioid receptors. Conclusion The present study suggests that high-frequency (100 Hz) EA stimulation of bilateral Feng-Chi acupoints exhibits no benefit in improving pilocarpine-induced sleep disruptions; in contrast, EA further deteriorated sleep disturbances. Opioid receptors in the CeA mediated EA-induced exacerbation of sleep disruptions in epileptic rats. PMID:24215575

  12. Characterization of the cell-mediated cytotoxic responses of isogeneic ginbuna crucian carp induced by oral immunisation with hapten-modified cellular antigens.

    PubMed

    Sato, Atsushi; Okamoto, Nobuaki

    2008-06-01

    A better understanding of the immune responses in fish elicited by oral immunisation is of importance for the development of new and effective oral vaccines for cultured fish. In the present study, we characterized specific cell-mediated cytotoxic responses in isogeneic ginbuna crucian carp (Carassius auratus langsdorfii) following oral immunisation with cellular antigens. Trinitrophenyl- (TNP) or dinitrophenyl- (DNP) modified syngeneic and allogeneic cells were used for studying the fine specificity and genetic restriction of orally-induced cytotoxic cells. Hapten-specific cytotoxic responses were detected in peripheral blood leukocytes (PBLs) of fish orally immunised with haptenated syngeneic cells. PBLs from orally immunised fish had cytolytic activity for haptenated syngeneic cells, but they showed little reactivity against both haptenated and unmodified allogeneic targets. Similarly, oral immunisation of fish with hapten-modified allogeneic cells did not induce hapten-specific cytotoxic cells which can lyse haptenated syngeneic targets. Although ginbuna crucian carp possess spontaneous cytotoxic cells that are capable of killing mammalian tumour cells, cold target inhibition studies suggested that such spontaneous cytotoxic cells were not involved in the killing of haptenated syngeneic targets. Oral immunisation of fish with haptenated syngeneic cells also induced hapten-specific cytotoxic memory responses. Oral administration of haptenated fixed cells also effectively induced hapten-specific cytotoxic cells in the treated fish. These findings suggest that oral immunisation with antigens can elicit antigen-specific cytotoxic cells that are capable of recognizing antigens in an MHC-restricted manner. In addition, our results provide indirect evidence that fish possess a mechanism for taking up exogenous non-replicating antigens from the alimentary tract and generating antigen-specific cytotoxic cells.

  13. 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.

  14. 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.

  15. 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

  16. Poly (ADP-ribose) polymerase mediates diabetes-induced retinal neuropathy.

    PubMed

    Mohammad, Ghulam; Siddiquei, Mohammad Mairaj; Abu El-Asrar, Ahmed M

    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. 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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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.

  5. Mcl-1 protects prostate cancer cells from cell death mediated by chemotherapy-induced DNA damage

    PubMed Central

    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

  6. 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

  7. Arabidopsis FORGETTER1 mediates stress-induced chromatin memory through nucleosome remodeling

    PubMed Central

    Brzezinka, Krzysztof; Altmann, Simone; Czesnick, Hjördis; Nicolas, Philippe; Gorka, Michal; Benke, Eileen; Kabelitz, Tina; Jähne, Felix; Graf, Alexander; Kappel, Christian; Bäurle, Isabel

    2016-01-01

    Plants as sessile organisms can adapt to environmental stress to mitigate its adverse effects. As part of such adaptation they maintain an active memory of heat stress for several days that promotes a more efficient response to recurring stress. We show that this heat stress memory requires the activity of the FORGETTER1 (FGT1) locus, with fgt1 mutants displaying reduced maintenance of heat-induced gene expression. FGT1 encodes the Arabidopsis thaliana orthologue of Strawberry notch (Sno), and the protein globally associates with the promoter regions of actively expressed genes in a heat-dependent fashion. FGT1 interacts with chromatin remodelers of the SWI/SNF and ISWI families, which also display reduced heat stress memory. Genomic targets of the BRM remodeler overlap significantly with FGT1 targets. Accordingly, nucleosome dynamics at loci with altered maintenance of heat-induced expression are affected in fgt1. Together, our results suggest that by modulating nucleosome occupancy, FGT1 mediates stress-induced chromatin memory. DOI: http://dx.doi.org/10.7554/eLife.17061.001 PMID:27680998

  8. Endoplasmic reticulum stress pathway mediates isoflurane-induced neuroapoptosis and cognitive impairments in aged rats.

    PubMed

    Ge, Hong-Wei; Hu, Wen-Wen; Ma, Lei-Lei; Kong, Fei-Juan

    2015-11-01

    Postoperative cognitive dysfunction (POCD) is increasingly being recognized as an important clinical syndrome. Although it has been documented that volatile anesthetics induce neuronal apoptosis and cognitive deficits in several aged animal models, the underlying mechanisms are not well understood. Endoplasmic reticulum stress (ERS) is considered as an initial or early response of cells under stress and linked to neuronal death in various neurodegenerative diseases. The study was designed to explore the possible role of ERS pathway in isoflurane-induced neuroapoptosis and cognitive impairments. In the present study, twenty-month-old rats were exposed to 1.3% isoflurane for 4h. Two weeks later, the rats were subjected to behavioral study. Protein and mRNA expressions of ERS markers were evaluated. Meanwhile, hippocampal neuronal apoptosis was also detected. We found that isoflurane triggered ERS as evidenced by increased phosphorylation of eukaryotic initiation factor (EIF) 2α, and increased expression of 78-kDa glucose-regulated protein (GRP78), activating transcription factor (ATF) 4 and C/EBP homologous protein (CHOP). Furthermore, the level of apoptosis in the hippocampus was significantly up-regulated after isoflurane exposure, and salubrinal (ERS inhibitor) treatment attenuated the increase. More importantly, cognitive impairments caused by isoflurane were also effectively alleviated by salubrinal pretreatment. These results indicate that ERS-mediated apoptotic pathway is involved in isoflurane neurotoxicity in aged rats. Inhibition of ERS overactivation contributes to the relief of isoflurane-induced neurohistopathologic changes. PMID:26162760

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

    PubMed

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

    2015-10-23

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

  10. 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

  11. 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

  12. TRPV1 and TRPA1 Mediate Peripheral Nitric Oxide-Induced Nociception in Mice

    PubMed Central

    Miyamoto, Takashi; Dubin, Adrienne E.; Petrus, Matt J.; Patapoutian, Ardem

    2009-01-01

    Nitric oxide (NO) can induce acute pain in humans and plays an important role in pain sensitization caused by inflammation and injury in animal models. There is evidence that NO acts both in the central nervous system via a cyclic GMP pathway and in the periphery on sensory neurons through unknown mechanisms. It has recently been suggested that TRPV1 and TRPA1, two polymodal ion channels that sense noxious stimuli impinging on peripheral nociceptors, are activated by NO in heterologous systems. Here, we investigate the relevance of this activation. We demonstrate that NO donors directly activate TRPV1 and TRPA1 in isolated inside-out patch recordings. Cultured primary sensory neurons display both TRPV1- and TRPA1-dependent responses to NO donors. BH4, an essential co-factor for NO production, causes activation of a subset of DRG neurons as assayed by calcium imaging, and this activation is at least partly dependent on nitric oxide synthase activity. We show that BH4-induced calcium influx is ablated in DRG neurons from TRPA1/TRPV1 double knockout mice, suggesting that production of endogenous levels of NO can activate these ion channels. In behavioral assays, peripheral NO-induced nociception is compromised when TRPV1 and TRPA1 are both ablated. These results provide genetic evidence that the peripheral nociceptive action of NO is mediated by both TRPV1 and TRPA1. PMID:19893614

  13. 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

  14. 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.

  15. 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

  16. Equine Torovirus (BEV) Induces Caspase-Mediated Apoptosis in Infected Cells

    PubMed Central

    Maestre, Ana M.; Garzón, Ana; Rodríguez, Dolores

    2011-01-01

    Toroviruses are gastroenteritis causing agents that infect different animal species and humans. To date, very little is known about how toroviruses cause disease. Here, we describe for the first time that the prototype member of this genus, the equine torovirus Berne virus (BEV), induces apoptosis in infected cells at late times postinfection. Observation of BEV infected cells by electron microscopy revealed that by 24 hours postinfection some cells exhibited morphological characteristics of apoptotic cells. Based on this finding, we analyzed several apoptotic markers, and observed protein synthesis inhibition, rRNA and DNA degradation, nuclear fragmentation, caspase-mediated cleavage of PARP and eIF4GI, and PKR and eIF2α phosphorylation, all these processes taking place after peak virus production. We also determined that both cell death receptor and mitochondrial pathways are involved in the apoptosis process induced by BEV. BEV-induced apoptosis at late times postinfection, once viral progeny are produced, could facilitate viral dissemination in vivo and contribute to viral pathogenesis. PMID:21698249

  17. Exchange factors directly activated by cAMP mediate melanocortin 4 receptor-induced gene expression.

    PubMed

    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

  18. JNK interaction with Sab mediates ER stress induced inhibition of mitochondrial respiration and cell death.

    PubMed

    Win, S; Than, T A; Fernandez-Checa, J C; Kaplowitz, N

    2014-01-09

    Our aim was to better understand the mechanism and importance of sustained c-Jun N-terminal kinase (JNK) activation in endoplasmic reticulum (ER) stress and effects of ER stress on mitochondria by determining the role of mitochondrial JNK binding protein, Sab. Tunicamycin or brefeldin A induced a rapid and marked decline in basal mitochondrial respiration and reserve-capacity followed by delayed mitochondrial-mediated apoptosis. Knockdown of mitochondrial Sab prevented ER stress-induced sustained JNK activation, impaired respiration, and apoptosis, but did not alter the magnitude or time course of activation of ER stress pathways. P-JNK plus adenosine 5'-triphosphate (ATP) added to isolated liver mitochondria promoted superoxide production, which was amplified by addition of calcium and inhibited by a blocking peptide corresponding to the JNK binding site on Sab (KIM1). This peptide also blocked tunicamycin-induced inhibition of cellular respiration. In conclusion, ER stress triggers an interaction of JNK with mitochondrial Sab, which leads to impaired respiration and increased mitochondrial reactive oxygen species, sustaining JNK activation culminating in apoptosis.

  19. RhoA and ROCK mediate histamine-induced vascular leakage and anaphylactic shock.

    PubMed

    Mikelis, Constantinos M; Simaan, May; Ando, Koji; Fukuhara, Shigetomo; Sakurai, Atsuko; Amornphimoltham, Panomwat; Masedunskas, Andrius; Weigert, Roberto; Chavakis, Triantafyllos; Adams, Ralf H; Offermanns, Stefan; Mochizuki, Naoki; Zheng, Yi; Gutkind, J Silvio

    2015-04-10

    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 signalling circuitry in vascular permeability, thereby identifying novel pharmacological targets for many human diseases characterized by aberrant vascular leakage.

  20. IFN-γ-Inducible Irga6 Mediates Host Resistance against Chlamydia trachomatis via Autophagy

    PubMed Central

    Braun, Peter R.; Zerrahn, Jens; Meyer, Thomas F.

    2009-01-01

    Chlamydial infection of the host cell induces Gamma interferon (IFNγ), a central immunoprotector for humans and mice. The primary defense against Chlamydia infection in the mouse involves the IFNγ-inducible family of IRG proteins; however, the precise mechanisms mediating the pathogen's elimination are unknown. In this study, we identify Irga6 as an important resistance factor against C. trachomatis, but not C. muridarum, infection in IFNγ-stimulated mouse embryonic fibroblasts (MEFs). We show that Irga6, Irgd, Irgm2 and Irgm3 accumulate at bacterial inclusions in MEFs upon stimulation with IFNγ, whereas Irgb6 colocalized in the presence or absence of the cytokine. This accumulation triggers a rerouting of bacterial inclusions to autophagosomes that subsequently fuse to lysosomes for elimination. Autophagy-deficient Atg5−/− MEFs and lysosomal acidification impaired cells surrender to infection. Irgm2, Irgm3 and Irgd still localize to inclusions in IFNγ-induced Atg5−/− cells, but Irga6 localization is disrupted indicating its pivotal role in pathogen resistance. Irga6-deficient (Irga6−/−) MEFs, in which chlamydial growth is enhanced, do not respond to IFNγ even though Irgb6, Irgd, Irgm2 and Irgm3 still localize to inclusions. Taken together, we identify Irga6 as a necessary factor in conferring host resistance by remodelling a classically nonfusogenic intracellular pathogen to stimulate fusion with autophagosomes, thereby rerouting the intruder to the lysosomal compartment for destruction. PMID:19242543

  1. The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling.

    PubMed

    Muñoz, Juan Pablo; Collao, Andres; Chiong, Mario; Maldonado, Carola; Adasme, Tatiana; Carrasco, Loreto; Ocaranza, Paula; Bravo, Roberto; Gonzalez, Leticia; Díaz-Araya, Guillermo; Hidalgo, Cecilia; Lavandero, Sergio

    2009-10-01

    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. PMID:19654000

  2. The anthracenedione compound bostrycin induces mitochondria-mediated apoptosis in the yeast Saccharomyces cerevisiae.

    PubMed

    Xu, Chunling; Wang, Jiafeng; Gao, Ye; Lin, Huangyu; Du, Lin; Yang, Shanshan; Long, Simei; She, Zhigang; Cai, Xiaoling; Zhou, Shining; Lu, Yongjun

    2010-05-01

    Bostrycin is an anthracenedione with phytotoxic and antibacterial activity that belongs to the large family of quinones. We have isolated bostrycin from the secondary metabolites of a mangrove endophytic fungus, no. 1403, collected from the South China Sea. Using the yeast Saccharomyces cerevisiae as a model, we show that bostrycin inhibits cell proliferation by blocking the cell cycle at G1 phase and ultimately leads to cell death in a time- and dose-dependent manner. Bostrycin-induced lethal cytotoxicity is accompanied with increased levels of intracellular reactive oxygen species and hallmarks of apoptosis such as chromatin condensation, DNA fragmentation and externalization of phosphatidylserine. We further show that bostrycin decreases mitochondrial membrane electric potential and causes mitochondrial destruction during the progression of cell death. Bostrycin-induced cell death was promoted in YCA1 null yeast strain but was partially rescued in AIF1 null mutant both in fermentative and respiratory media, strongly indicating that bostrycin induces apoptosis in yeast cells through a mitochondria-mediated but caspase-independent pathway.

  3. Combination therapies in adjuvant with topical ALA-mediated ph