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Sample records for activating intrinsic pathway

  1. Proinflammatory cytokines activate the intrinsic apoptotic pathway in beta-cells

    DEFF Research Database (Denmark)

    Grunnet, Lars G; Aikin, Reid; Tonnesen, Morten F

    2009-01-01

    of the intrinsic apoptotic pathway and the role of the two proapoptotic Bcl-2 proteins, Bad and Bax, were examined in beta-cells. RESEARCH DESIGN AND METHODS: Human and rat islets and INS-1 cells were exposed to a combination of proinflammatory cytokines (interleukin-1beta, interferon-gamma, and/or tumor necrosis...... to investigate the role of Bad and Bax activation, respectively. RESULTS: We found that proinflammatory cytokines induced calcineurin-dependent dephosphorylation of Bad Ser136, mitochondrial stress, cytochrome c release, activation of caspase-9 and -3, and DNA fragmentation. Inhibition of Bad Ser136...... dephosphorylation or Bax was found to inhibit cytokine-induced intrinsic proapoptotic signaling. CONCLUSIONS: Our findings demonstrate that the intrinsic mitochondrial apoptotic pathway contributes significantly to cytokine-induced beta-cell death and suggest a functional role of calcineurin-mediated Bad Ser136...

  2. Vasopressin Impairment During Sepsis Is Associated with Hypothalamic Intrinsic Apoptotic Pathway and Microglial Activation.

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    da Costa, Luis Henrique Angenendt; Júnior, Nilton Nascimento Dos Santos; Catalão, Carlos Henrique Rocha; Sharshar, Tarek; Chrétien, Fabrice; da Rocha, Maria José Alves

    2017-09-01

    Previous studies have shown that in the early phase of sepsis, the plasma concentration of arginine vasopressin (AVP) is increased, but in the late phase, its levels remain inadequately low, despite of persistent hypotension. One hypothesis suggested for this relative deficiency is apoptosis of vasopressinergic neurons. Here, we investigated apoptosis pathways in the hypothalamus during sepsis, as well as mechanisms underlying this process. Male Wistar rats were submitted to sepsis by cecal ligation and puncture (CLP) or nonmanipulated (naive) as control. After 6 and 24 h, the animals were decapitated and brain and blood were collected to assess hypothalamic apoptotic markers, IFN-γ plasma levels, and evidence for breakdown of the blood-brain barrier (BBB). Sepsis caused a decrease in mitochondrial antiapoptotic proteins (Bcl-2, Bcl-xL) in the hypothalamus, but had no effect on markers of cell death mediated by death receptors or immune cells. In the supraoptic nuclei of these animals, microglia morphology was consistent with activation, associated with an increase in plasma IFN-γ. A transitory breakdown of BBB in the hypothalamus was seen at 6 h following CLP. The results indicate that the intrinsic but not extrinsic apoptosis pathway is involved in the cell death observed in vasopressinergic neurons, and that this condition is temporally associated with microglial activation and BBB leaking.

  3. Activation of the intrinsic-apoptotic pathway in LNCaP prostate cancer cells by genistein- topotecan combination treatments

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    Vanessa Hörmann

    2013-03-01

    Full Text Available ABSTRACTBackground: Prostate cancer is the second most common cancer in American men. The development of alternative preventative and/or treatment options utilizing a combination of phytochemicals and chemotherapeutic drugs could be an attractive alternative compared to conventional carcinoma treatments. Genistein isoflavone is the primary dietary phytochemical found in soy and has demonstrated anti-tumor activities in LNCaP prostate cancer cells. Topotecan Hydrochloride (Hycamtin is an FDA-approved chemotherapy for secondary treatment of lung, ovarian and cervical cancers. The purpose of this study was to detail the potential activation of the intrinsic apoptotic pathway in LNCaP prostate cancer cells through genistein-topotecan combination treatments.Methods: LNCaP cells were cultured in complete RPMI medium in a monolayer (70-80% confluency at 37ºC and 5% CO2. Treatment consisted of single and combination groups of genistein and topotecan for 24 hours. The treated cells were assayed for i growth inhibition through trypan blue exclusion assay and microphotography , ii classification of cellular death through acridine/ ethidium bromide fluorescent staining, and iii activation of the intrinsic apoptotic pathway through Jc-1: mitochondrial membrane potential assay, cytochrome c release and Bcl-2 protein expression.Results: The overall data indicated that genistein-topotecan combination was significantly more efficacious in reducing the prostate carcinoma’s viability compared to the single treatment options. In all treatment groups, cell death occurred primarily through the activation of the intrinsic apoptotic pathway.Conclusion: The combination of topotecan and genistein has the potential to lead to treatment options with equal therapeutic efficiency as traditional chemo- and radiation therapies, but lower cell cytotoxicity and fewer side effects in patients.

  4. Luteolin induces intrinsic apoptosis via inhibition of E6/E7 oncogenes and activation of extrinsic and intrinsic signaling pathways in HPV-18-associated cells.

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    Ham, Sunyoung; Kim, Ki Hong; Kwon, Tae Ho; Bak, Yesol; Lee, Dong Hun; Song, Yong Seok; Park, Su-Ho; Park, Yun Sun; Kim, Man Sub; Kang, Jeong Woo; Hong, Jin Tae; Yoon, Do-Young

    2014-06-01

    Luteolin, a flavonoid extracted from a number of plants with recognized anticancer, anti-inflammatory and anti-oxidative activities, inhibits angiogenic processes and modulates multidrug resistance. However, the efficacy and mechanisms of action of this flavonoid agent are still undergoing study. In order to elucidate whether luteolin exhibits an anticancer effect in cervical cancer cells, HeLa cells were incubated with luteolin and apoptosis was assessed by observing nuclear morphological changes, and performing Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. Cell cycle analysis, western blotting, RT-PCR and mitochondrial membrane potential measurements were also carried out. Luteolin showed a significant dose-dependent cytotoxic effect only in human papillomavirus (HPV)-positive cervical cancer cells, when compared to its effect on HPV-negative cervical cancer C33A cells. Expression levels of human papilloma virus E6 and E7 oncogenes were suppressed, those of related factors pRb and p53 were recovered and E2F5 was increased by luteolin treatment. Furthermore, luteolin enhanced the expression of death receptors and death receptor downstream factors such as Fas/FasL, DR5/TRAIL and FADD in HeLa cells, and activated caspase cascades. In particular, luteolin enhanced the activity of caspase-3 and -8 in a dose-dependent manner. Activation of caspase-3 induced caspase-8 activity and vice versa. Luteolin also induced mitochondrial membrane potential collapse and cytochrome c release, and inhibited Bcl-2 and Bcl-xL expression. In conclusion, luteolin exerts anticarcinogenic activity through inhibition of E6 and E7 expression and cross-activation of caspase-3 and -8. Taken together, these results suggest that luteolin induces inactivation of HPV-18 oncogene expression and apoptosis by activating the intrinsic and extrinsic pathways.

  5. Distinct spatial activation of intrinsic and extrinsic apoptosis pathways in natural scrapie: association with prion-related lesions

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    Serrano, Carmen; Lyahyai, Jaber; Bolea, Rosa; Varona, Luis; Monleón, Eva; Badiola, Juan J.; Zaragoza, Pilar; Martín-Burriel, Inmaculada

    2009-01-01

    Neurodegeneration and gliosis are the main neuropathological features of prion diseases. However, the molecular mechanisms involved in these processes remain unclear. Several studies have demonstrated changes in the expression of apoptotic factors and inflammatory cytokines in animals with experimental infection. Here we present the expression profiles of 15 genes implicated in the intrinsic and extrinsic apoptotic pathways in the central nervous systems of sheep naturally infected with scrapie. Expression changes obtained by real-time RT-PCR were also compared with the extent of classical scrapie lesions, such as prion deposition, neuronal vacuolisation, spongiosis, and astrogliosis as well as with the activation of caspase-3, using a stepwise regression. The results suggest that the factors assessed participate in apoptotic or inflammatory functions, depending on the affected area. The mitochondrial apoptosis pathway was associated with prion deposition in the prefrontal cortex (the less affected area), and with activation of caspase-3-mediated cell death via over-expression of BAK. In addition to its known association with astroglial activation, the extrinsic apoptosis pathway was also related to cell death and neuronal vacuolisation. PMID:19401142

  6. γ-Tocotrienol induces apoptosis in human T cell lymphoma through activation of both intrinsic and extrinsic pathways.

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    Wilankar, Chandan; Khan, Nazir M; Checker, Rahul; Sharma, Deepak; Patwardhan, Raghavendra; Gota, Vikram; Sandur, Santosh Kumar; Devasagayam, T P A

    2011-01-01

    Tocotrienols are members of vitamin E family and possess broad biological activities including antioxidant, anti-inflammatory and antitumor effects. In the present study, we examine the potential of α-tocotrienol (AT) and γ-tocotrienol (GT) in inhibiting the proliferation of human T cell lymphoma Jurkat cells and elucidate the pathways involved in anti tumor effects of GT. GT but not AT inhibited proliferation and induced apoptosis in Jurkat cells in a dose dependent manner. GT treatment resulted in elevated mitochondrial ROS production, activation of JNK and suppression of ERK and p38 MAPK. GT also induced calcium release, loss of mitochondrial membrane potential and cytochrome c release from the mitochondria. These changes were accompanied by increase in Bax expression with a concomitant decrease in Bcl-xl expression suggesting activation of mitochondrial apoptotic pathway. GT induced increase in mitochondrial ROS was abrogated by catalase. Besides, GT also up-regulated surface expression of Fas and FasL on Jurkat cells. Further, caspase activation and PARP degradation were also seen in cells treated with GT. Inhibitors of caspase-8 and caspase-9 significantly abrogated GT mediated apoptosis. In contrast GT was not toxic to normal human peripheral blood mononuclear cells suggesting differential cytotoxicity towards normal lymphocytes and transformed lymphoma cells. Cellular uptake studies with tocotrienols showed higher intracellular accumulation of GT as compared to AT which may be responsible for its better antitumor activity. Our results show antitumor effects of GT in human lymphoma cells via increased mitochondrial ROS generation and activation of both intrinsic and extrinsic apoptotic pathways.

  7. P150glued-associated disorders are caused by activation of intrinsic apoptotic pathway.

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    Kei-Ichi Ishikawa

    Full Text Available Mutations in p150glued cause hereditary motor neuropathy with vocal cord paralysis (HMN7B and Perry syndrome (PS. Here we show that both overexpression of p150glued mutants and knockdown of endogenous p150glued induce apoptosis. Overexpression of a p150glued plasmid containing either a HMN7B or PS mutation resulted in cytoplasmic p150glued-positive aggregates and was associated with cell death. Cells containing mutant p150glued aggregates underwent apoptosis that was characterized by an increase in cleaved caspase-3- or Annexin V-positive cells and was attenuated by both zVAD-fmk (a pan-caspase inhibitor application and caspase-3 siRNA knockdown. In addition, overexpression of mutant p150glued decreased mitochondrial membrane potentials and increased levels of translocase of the mitochondrial outer membrane (Tom20 protein, indicating accumulation of damaged mitochondria. Importantly, siRNA knockdown of endogenous p150glued independently induced apoptosis via caspase-8 activation and was not associated with mitochondrial morphological changes. Simultaneous knockdown of endogenous p150glued and overexpression of mutant p150glued had additive apoptosis induction effects. These findings suggest that both p150glued gain-of-toxic-function and loss-of-physiological-function can cause apoptosis and may underlie the pathogenesis of p150glued-associated disorders.

  8. Isorhamnetin inhibits H₂O₂-induced activation of the intrinsic apoptotic pathway in H9c2 cardiomyocytes through scavenging reactive oxygen species and ERK inactivation.

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    Sun, Bing; Sun, Gui-Bo; Xiao, Jing; Chen, Rong-Chang; Wang, Xin; Wu, Ying; Cao, Li; Yang, Zhi-Hong; Sun, Xiao-Bo

    2012-02-01

    As a traditional Chinese medicine, the sea buckthorn (Hippophae rhamnoides L.) has a long history in the treatment of ischemic heart disease and circulatory disorders. However, the active compounds responsible for and the underlying mechanisms of these effects are not fully understood. In this article, isorhamnetin pretreatment counteracted H(2)O(2)-induced apoptotic damage in H9c2 cardiomyocytes. Isorhamnetin did not inhibit the death receptor-dependent or extrinsic apoptotic pathways, as characterized by its absence in both caspase-8 inactivation and tBid downregulation along with unchanged Fas and TNFR1 mRNA levels. Instead, isorhamnetin specifically suppressed the mitochondria-dependent or intrinsic apoptotic pathways, as characterized by inactivation of caspase-9 and -3, maintenance of the mitochondrial membrane potential (ΔΨm), and regulation of a series of Bcl-2 family genes upstream of ΔΨm. The anti-apoptotic effects of isorhamnetin were linked to decreased ROS generation. H(2)O(2) activated ERK and p53, whereas isorhamnetin inhibited their activation. ERK overexpression overrode the isorhamnetin-induced inhibition of the intrinsic apoptotic pathway in H9c2 cardiomyocytes, which indicated that an ERK-dependent pathway was involved. Furthermore, N-acetyl cysteine (a potent ROS scavenger) could attenuate the H(2)O(2)-induced apoptosis. However, PD98059 (an ERK-specific inhibitor) could not effectively antagonize ROS generation, which indicates that ROS may be an upstream inducer of ERK. In conclusion, isorhamnetin inhibits the H(2)O(2)-induced activation of the intrinsic apoptotic pathway via ROS scavenging and ERK inactivation. Therefore, isorhamnetin is a promising reagent for the treatment of ROS-induced cardiomyopathy.

  9. Melanopsin Variants as Intrinsic Optogenetic On and Off Switches for Transient versus Sustained Activation of G Protein Pathways.

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    Spoida, Katharina; Eickelbeck, Dennis; Karapinar, Raziye; Eckhardt, Tobias; Mark, Melanie D; Jancke, Dirk; Ehinger, Benedikt Valerian; König, Peter; Dalkara, Deniz; Herlitze, Stefan; Masseck, Olivia A

    2016-05-09

    G-protein-coupled receptors (GPCRs) represent the major protein family for cellular modulation in mammals. Therefore, various strategies have been developed to analyze the function of GPCRs involving pharmaco- and optogenetic approaches [1, 2]. However, a tool that combines precise control of the activation and deactivation of GPCR pathways and/or neuronal firing with limited phototoxicity is still missing. We compared the biophysical properties and optogenetic application of a human and a mouse melanopsin variant (hOpn4L and mOpn4L) on the control of Gi/o and Gq pathways in heterologous expression systems and mouse brain. We found that GPCR pathways can be switched on/off by blue/yellow light. The proteins differ in their kinetics and wavelength dependence to activate and deactivate G protein pathways. Whereas mOpn4L is maximally activated by very short light pulses, leading to sustained G protein activation, G protein responses of hOpn4L need longer light pulses to be activated and decline in amplitude. Based on the different biophysical properties, brief light activation of mOpn4L is sufficient to induce sustained neuronal firing in cerebellar Purkinje cells (PC), whereas brief light activation of hOpn4L induces AP firing, which declines in frequency over time. Most importantly, mOpn4L-induced sustained firing can be switched off by yellow light. Based on the biophysical properties, hOpn4L and mOpn4L represent the first GPCR optogenetic tools, which can be used to switch GPCR pathways/neuronal firing on an off with temporal precision and limited phototoxicity. We suggest to name these tools moMo and huMo for future optogenetic applications.

  10. Overcoming intrinsic inhibitory pathways to augment the antineoplastic activity of adoptively transferred T cells: Re-tuning your CAR before hitting a rocky road.

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    Wang, Liang-Chuan S; Riese, Matthew J; Moon, Edmund K; Albelda, Steven M

    2013-11-01

    Effector T cells become rapidly inactivated after antigen exposure due to extracellular as well as intrinsic signals. We have recently demonstrated that the deletion of diacylglycerol kinases, intrinsic inhibitors of T-cell signaling, enhances the activity of adoptively transferred T cells expressing a chimeric antigen receptor (CAR) specific for a tumor-associated antigen.

  11. Intrinsic Patterns of Human Activity

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    Hu, Kun; Ivanov, Plamen Ch.; Chen, Zhi; Hilton, Michael; Stanley, H. Eugene; Shea, Steven

    2003-03-01

    Activity is one of the defining features of life. Control of human activity is complex, being influenced by many factors both extrinsic and intrinsic to the body. The most obvious extrinsic factors that affect activity are the daily schedule of planned events, such as work and recreation, as well as reactions to unforeseen or random events. These extrinsic factors may account for the apparently random fluctuations in human motion observed over short time scales. The most obvious intrinsic factors are the body clocks including the circadian pacemaker that influences our sleep/wake cycle and ultradian oscillators with shorter time scales [2, 3]. These intrinsic rhythms may account for the underlying regularity in average activity level over longer periods of up to 24 h. Here we ask if the known extrinsic and intrinsic factors fully account for all complex features observed in recordings of human activity. To this end, we measure activity over two weeks from forearm motion in subjects undergoing their regular daily routine. Utilizing concepts from statistical physics, we demonstrate that during wakefulness human activity possesses previously unrecognized complex dynamic patterns. These patterns of activity are characterized by robust fractal and nonlinear dynamics including a universal probability distribution and long-range power-law correlations that are stable over a wide range of time scales (from minutes to hours). Surprisingly, we find that these dynamic patterns are unaffected by changes in the average activity level that occur within individual subjects throughout the day and on different days of the week, and between subjects. Moreover, we find that these patterns persist when the same subjects undergo time-isolation laboratory experiments designed to account for the phase of the circadian pacemaker, and control the known extrinsic factors by restricting behaviors and manipulating scheduled events including the sleep/wake cycle. We attribute these newly

  12. Anti-tumour activity of a novel coumarin-chalcone hybrid is mediated through intrinsic apoptotic pathway by inducing PUMA and altering Bax/Bcl-2 ratio.

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    Singh, Neetu; Sarkar, Jayanta; Sashidhara, Koneni V; Ali, Shakir; Sinha, Sudhir

    2014-06-01

    Coumarins and chalcones are secondary plant metabolites which have shown an array of pharmacological properties including anti-tumour activity. We have previously reported on the synthesis and anti-proliferative activity of a series of novel coumarin-chalcone hybrids. Now we report on the in vivo efficacy as well as mechanism of action of the most potent molecule of the series, S009-131. Oral administration of this molecule resulted in regression of tumours induced by HeLa cell xenografts in nod SCID mice. The molecule inhibited proliferation of cervical cancer cells (HeLa and C33A) by inducing apoptosis and arresting cell cycle at G2/M phase. Apoptosis was induced through induction of caspase-dependent intrinsic pathway and alterations in the cellular levels of Bcl-2 family proteins. The mitochondrial transmembrane potential got highly depleted in S009-131 treated cells due to an increase in Bax/Bcl-2 ratio and intracellular ROS. The molecule induced release of cytochrome c into the cytosol and activation of initiator caspase-9 and executioner caspases-3/7. Tumour suppressor protein p53 and its transcriptional target PUMA were up regulated, suggesting their role in mediating the cell death. These results suggest that S009-131 is a potent candidate for the chemotherapy of cervical carcinoma.

  13. Zinc ferrite nanoparticles activate IL-1b, NFKB1, CCL21 and NOS2 signaling to induce mitochondrial dependent intrinsic apoptotic pathway in WISH cells

    Energy Technology Data Exchange (ETDEWEB)

    Saquib, Quaiser; Al-Khedhairy, Abdulaziz A.; Ahmad, Javed; Siddiqui, Maqsood A.; Dwivedi, Sourabh; Khan, Shams T. [Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Chair for DNA Research, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Musarrat, Javed, E-mail: musarratj1@yahoo.com [Chair for DNA Research, Department of Zoology, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Department of Agricultural Microbiology, Faculty of Agricultural Sciences, Aligarh Muslim University, Aligarh 202002, U.P. (India)

    2013-12-01

    The present study has demonstrated the translocation of zinc ferrite nanoparticles (ZnFe{sub 2}O{sub 4}-NPs) into the cytoplasm of human amnion epithelial (WISH) cells, and the ensuing cytotoxicity and genetic damage. The results suggested that in situ NPs induced oxidative stress, alterations in cellular membrane and DNA strand breaks. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and neutral red uptake (NRU) cytotoxicity assays indicated 64.48 ± 1.6% and 50.73 ± 2.1% reduction in cell viability with 100 μg/ml of ZnFe{sub 2}O{sub 4}-NPs exposure. The treated WISH cells exhibited 1.2-fold higher ROS level with 0.9-fold decline in membrane potential (ΔΨm) and 7.4-fold higher DNA damage after 48 h of ZnFe{sub 2}O{sub 4}-NPs treatment. Real-time PCR (qPCR) analysis of p53, CASP 3 (caspase-3), and bax genes revealed 5.3, 1.6, and 14.9-fold upregulation, and 0.18-fold down regulation of bcl 2 gene vis-à-vis untreated control. RT{sup 2} Profiler™ PCR array data elucidated differential up-regulation of mRNA transcripts of IL-1b, NFKB1, NOS2 and CCL21 genes in the range of 1.5 to 3.7-folds. The flow cytometry based cell cycle analysis suggested the transfer of 15.2 ± 2.1% (p < 0.01) population of ZnFe{sub 2}O{sub 4}-NPs (100 μg/ml) treated cells into apoptotic phase through intrinsic pathway. Over all, the data revealed the potential of ZnFe{sub 2}O{sub 4}-NPs to induce cellular and genetic toxicity in cells of placental origin. Thus, the significant ROS production, reduction in ΔΨm, DNA damage, and activation of genes linked to inflammation, oxidative stress, proliferation, DNA damage and repair could serve as the predictive toxicity and stress markers for ecotoxicological assessment of ZnFe{sub 2}O{sub 4}-NPs induced cellular and genetic damage. - Highlights: • First report on the molecular toxicity of ZnFe{sub 2}O{sub 4}-NPs in cells of placental origin • WISH cells treated with ZnFe{sub 2}O{sub 4}-NPs exhibited cytoplasmic

  14. Zinc ferrite nanoparticles activate IL-1b, NFKB1, CCL21 and NOS2 signaling to induce mitochondrial dependent intrinsic apoptotic pathway in WISH cells.

    Science.gov (United States)

    Saquib, Quaiser; Al-Khedhairy, Abdulaziz A; Ahmad, Javed; Siddiqui, Maqsood A; Dwivedi, Sourabh; Khan, Shams T; Musarrat, Javed

    2013-12-01

    The present study has demonstrated the translocation of zinc ferrite nanoparticles (ZnFe2O4-NPs) into the cytoplasm of human amnion epithelial (WISH) cells, and the ensuing cytotoxicity and genetic damage. The results suggested that in situ NPs induced oxidative stress, alterations in cellular membrane and DNA strand breaks. The [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) and neutral red uptake (NRU) cytotoxicity assays indicated 64.48 ± 1.6% and 50.73 ± 2.1% reduction in cell viability with 100 μg/ml of ZnFe2O4-NPs exposure. The treated WISH cells exhibited 1.2-fold higher ROS level with 0.9-fold decline in membrane potential (ΔΨm) and 7.4-fold higher DNA damage after 48h of ZnFe2O4-NPs treatment. Real-time PCR (qPCR) analysis of p53, CASP 3 (caspase-3), and bax genes revealed 5.3, 1.6, and 14.9-fold upregulation, and 0.18-fold down regulation of bcl 2 gene vis-à-vis untreated control. RT(2) Profiler™ PCR array data elucidated differential up-regulation of mRNA transcripts of IL-1b, NFKB1, NOS2 and CCL21 genes in the range of 1.5 to 3.7-folds. The flow cytometry based cell cycle analysis suggested the transfer of 15.2 ± 2.1% (p<0.01) population of ZnFe2O4-NPs (100 μg/ml) treated cells into apoptotic phase through intrinsic pathway. Over all, the data revealed the potential of ZnFe2O4-NPs to induce cellular and genetic toxicity in cells of placental origin. Thus, the significant ROS production, reduction in ΔΨm, DNA damage, and activation of genes linked to inflammation, oxidative stress, proliferation, DNA damage and repair could serve as the predictive toxicity and stress markers for ecotoxicological assessment of ZnFe2O4-NPs induced cellular and genetic damage.

  15. alpha-Toxin is a mediator of Staphylococcus aureus-induced cell death and activates caspases via the intrinsic death pathway independently of death receptor signaling

    NARCIS (Netherlands)

    Bantel, H; Sinha, B; Domschke, W; Peters, G; Schulze-Osthoff, K; Jänicke, R U

    2001-01-01

    Infections with Staphylococcus aureus, a common inducer of septic and toxic shock, often result in tissue damage and death of various cell types. Although S. aureus was suggested to induce apoptosis, the underlying signal transduction pathways remained elusive. We show that caspase activation and DN

  16. Ouabain enhances ADPKD cell apoptosis via the intrinsic pathway

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    Gustavo eBlanco

    2016-03-01

    Full Text Available Progression of autosomal dominant polycystic kidney disease (ADPKD is highly influenced by factors circulating in blood. We have shown that the hormone ouabain enhances several characteristics of the ADPKD cystic phenotype, including the rate of cell proliferation, fluid secretion and the capacity of the cells to form cysts. In this work, we found that physiological levels of ouabain (3nM also promote programmed cell death of renal epithelial cells obtained from kidney cysts of patients with ADPKD (ADPKD cells. This was determined by Alexa Fluor 488 labeled-Annexin-V staining and TUNEL assay, both biochemical markers of apoptosis. Ouabain-induced apoptosis also takes place when ADPKD cell growth is blocked; suggesting that the effect is not secondary to the stimulatory actions of ouabain on cell proliferation. Ouabain alters the expression of BCL family of proteins, reducing BCL-2 and increasing BAX expression levels, anti- and pro-apoptotic mediators respectively. In addition, ouabain caused the release of cytochrome c from mitochondria. Moreover, ouabain activates caspase-3, a key executioner caspase in the cell apoptotic pathway, but did not affect caspase-8. This suggests that ouabain triggers ADPKD cell apoptosis by stimulating the intrinsic, but not the extrinsic pathway of programmed cell death. The apoptotic effects of ouabain are specific for ADPKD cells and do not occur in normal human kidney cells (NHK cells. Taken together with our previous observations, these results show that ouabain causes an imbalance in cell growth/death, to favor growth of the cystic cells. This event, characteristic of ADPKD, further suggests the importance of ouabain as a circulating factor that promotes ADPKD progression.

  17. Intrinsic and extrinsic mechanisms contribute to maintain the JAK/STAT pathway aberrantly activated in T-type large granular lymphocyte leukemia.

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    Teramo, Antonella; Gattazzo, Cristina; Passeri, Francesca; Lico, Albana; Tasca, Giulia; Cabrelle, Anna; Martini, Veronica; Frezzato, Federica; Trimarco, Valentina; Ave, Elisa; Boscaro, Elisa; Piazza, Francesco; Facco, Monica; Trentin, Livio; Semenzato, Gianpietro; Zambello, Renato

    2013-05-09

    The JAK/STAT pathway is altered in T-cell large granular lymphocytic leukemia. In all patients, leukemic LGLs display upregulation of phosphorylated STAT3 (P-STAT3) that activates expression of many antiapoptotic genes. To investigate the mechanisms maintaining STAT3 aberrantly phosphorylated using transcriptional protein and functional assays, we analyzed interleukin (IL)-6 and suppressor of cytokine signaling-3 (SOCS3), 2 key factors of the JAK/STAT pathway that induce and inhibit STAT3 activation, respectively. We showed that IL-6 was highly expressed and released by the patients' peripheral blood LGL-depleted population, accounting for a trans-signaling process. By neutralizing IL-6 or its specific receptor with specific antibodies, a significant reduction of P-STAT3 levels and, consequently, LGL survival was demonstrated. In addition, we found that SOCS3 was down-modulated in LGL and unresponsive to IL-6 stimulation. By treating neoplastic LGLs with a demethylating agent, IL-6-mediated SOCS3 expression was restored with consequent P-STAT3 and myeloid cell leukemia-1 down-modulation. Methylation in the SOCS3 promoter was not detectable, suggesting that an epigenetic inhibition mechanism occurs at a different site. Our data indicate that loss of the inhibitor SOCS3 cooperates with IL-6 to maintain JAK/STAT pathway activation, thus contributing to leukemic LGL survival, and suggest a role of demethylating agents in the treatment of this disorder.

  18. Intrinsic-mediated caspase activation is essential for cardiomyocyte hypertrophy

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    Putinski, Charis; Abdul-Ghani, Mohammad; Stiles, Rebecca; Brunette, Steve; Dick, Sarah A.; Fernando, Pasan; Megeney, Lynn A.

    2013-01-01

    Cardiomyocyte hypertrophy is the cellular response that mediates pathologic enlargement of the heart. This maladaptation is also characterized by cell behaviors that are typically associated with apoptosis, including cytoskeletal reorganization and disassembly, altered nuclear morphology, and enhanced protein synthesis/translation. Here, we investigated the requirement of apoptotic caspase pathways in mediating cardiomyocyte hypertrophy. Cardiomyocytes treated with hypertrophy agonists displayed rapid and transient activation of the intrinsic-mediated cell death pathway, characterized by elevated levels of caspase 9, followed by caspase 3 protease activity. Disruption of the intrinsic cell death pathway at multiple junctures led to a significant inhibition of cardiomyocyte hypertrophy during agonist stimulation, with a corresponding reduction in the expression of known hypertrophic markers (atrial natriuretic peptide) and transcription factor activity [myocyte enhancer factor-2, nuclear factor kappa B (NF-κB)]. Similarly, in vivo attenuation of caspase activity via adenoviral expression of the biologic effector caspase inhibitor p35 blunted cardiomyocyte hypertrophy in response to agonist stimulation. Treatment of cardiomyocytes with procaspase 3 activating compound 1, a small-molecule activator of caspase 3, resulted in a robust induction of the hypertrophy response in the absence of any agonist stimulation. These results suggest that caspase-dependent signaling is necessary and sufficient to promote cardiomyocyte hypertrophy. These results also confirm that cell death signal pathways behave as active remodeling agents in cardiomyocytes, independent of inducing an apoptosis response. PMID:24101493

  19. Dimer-dependent intrinsic/basal activity of the class B G protein-coupled receptor PAC1 promotes cellular anti-apoptotic activity through Wnt/β-catenin pathways that are associated with dimer endocytosis.

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    Rongjie Yu

    Full Text Available The high expression of PACAP (pituitary adenylate cyclase-activating polypeptide-preferring receptor PAC1 is associated with nerve injury and tumors. Our previous report (Yu R, et al. PLoS One 2012; 7: e51811 confirmed the dimerization of PAC1 and found that the M-PAC1 mutation in the N-terminal first Cys/Ala lost the ability to form dimers. In this study, Chinese hamster ovary (CHO-K1 cells overexpressing wild-type PAC1 (PAC1-CHO had significantly higher anti-apoptotic activities against serum withdrawal-induced apoptosis associated with a lower caspase 3 activity and a higher Bcl-2 level in a ligand-independent manner than those of CHO cells overexpressing the mutant M-PAC1 (M-PAC1-CHO. PAC1-CHO had significantly higher β-catenin, cyclin D1 and c-myc levels corresponding to the Wnt/β-catenin signal than did M-PAC1-CHO. In addition, the Wnt/β-catenin pathway inhibitor XAV939 significantly inhibited the anti-apoptotic activities of PAC1-CHO. Top-flash assays demonstrated that PAC1-CHO had a significantly stronger Wnt/β-catenin signal than did M-PAC1-CHO. Acetylcysteine (NAC as an inhibitor of the dimerization of PAC1 inhibited the anti-apoptotic activities that were endowed by PAC1 and decreased the Wnt/β-catenin signal in Top-flash assays. In the PAC1 Tet (tetracycline-on inducible gene expression system by doxycycline (Dox, higher expression levels of PAC1 resulted in higher anti-apoptotic activities that were associated with a stronger Wnt/β-catenin signal. A similar correlation was also found with the down-regulation of PAC1 in the Neuro2a neuroblastoma cell. BiFC combined with fluorescence confocal imaging indicated that during serum-withdrawal-induced apoptosis, PAC1 dimers displayed significant endocytosis. These findings indicate that PAC1 has ligand-independent and dimer-dependent intrinsic/basal activity, conferring cells with anti-apoptotic activities against serum withdrawal, which is involved in the Wnt/β-catenin signal and

  20. The grape component piceatannol induces apoptosis in DU145 human prostate cancer cells via the activation of extrinsic and intrinsic pathways.

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    Kim, Eun Ji; Park, Heesook; Park, So Young; Jun, Jong-Gab; Park, Jung Han Yoon

    2009-10-01

    Piceatannol (trans-3,4,3',5'-tetrahydroxystilbene) is a polyphenol that is found in grapes, red wine, Rheum undulatum, and the seeds of Euphorbia lagascae. It has been previously reported that piceatannol inhibits the proliferation of a variety of cancer cell types. In the present study, we assessed the effects of piceatannol on the growth of androgen-insensitive DU145 prostate cancer cells at concentrations of 1-10 micromol/L. Piceatannol reduced the viable numbers and increased the numbers of apoptotic DU145 cells in a dose-dependent manner. Western blot analysis revealed that piceatannol increased the protein levels of cleaved caspase-8, -9, -7, and -3 and cleaved poly(ADP-ribose) polymerase (PARP). Piceatannol increased mitochondrial membrane permeability and cytochrome c release from the mitochondria to the cytosol. Piceatannol induced an increase in the levels of truncated Bid, Bax, Bik, Bok, and Fas but caused a decrease in the levels of Mcl-1 and Bcl-xL. Caspase-8 and -9 inhibitors mitigated piceatannol-induced apoptosis. The caspase-8 inhibitor suppressed the piceatannol-induced cleavage of Bid, caspase-3, and PARP. These results indicate that piceatannol induces apoptosis via the activation of the death receptor and mitochondrial-dependent pathways in prostate cancer cells.

  1. Ferulago angulata activates intrinsic pathway of apoptosis in MCF-7 cells associated with G1 cell cycle arrest via involvement of p21/p27

    Directory of Open Access Journals (Sweden)

    Karimian H

    2014-09-01

    Full Text Available Hamed Karimian,1 Soheil Zorofchian Moghadamtousi,2 Mehran Fadaeinasab,3 Shahram Golbabapour,2 Mahboubeh Razavi,1 Maryam Hajrezaie,2 Aditya Arya,1 Mahmood Ameen Abdulla,4 Syam Mohan,5 Hapipah Mohd Ali,2 Mohamad Ibrahim Noordin1 1Department of Pharmacy, Faculty of Medicine, 2Institute of Biological Sciences, Faculty of Science, 3Department of Chemistry, 4Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia, 5Medical Research Centre, Jazan University, Jazan, Saudi Arabia Abstract: Ferulago angulata is a medicinal plant that is traditionally known for its ­anti-inflammatory and antiulcer properties. The present study was aimed to evaluate its anticancer activity and the possible mechanism of action using MCF-7 as an in vitro model. F. angulata leaf extracts were prepared using solvents in the order of increasing polarity. As determined by MTT assay, F. angulata leaves hexane extract (FALHE revealed the strongest cytotoxicity against MCF-7 cells with the half maximal inhibitory concentration (IC50 value of 5.3±0.82 µg/mL. The acute toxicity study of FALHE provided evidence of the safety of the plant extract. Microscopic and flow cytometric analysis using annexin-V probe showed an induction of apoptosis in MCF-7 by FALHE. Treatment of MCF-7 cells with FALHE encouraged the intrinsic pathway of apoptosis, with cell death transducing signals that reduced the mitochondrial membrane potential with cytochrome c release from mitochondria to cytosol. The released cytochrome c triggered the activation of caspase-9. Meanwhile, the overexpression of caspase-8 suggested the involvement of an extrinsic pathway in the induced apoptosis at the late stage of treatment. Moreover, flow cytometric analysis showed that FALHE treatment significantly arrested MCF-7 cells in the G1 phase, which was associated with upregulation of p21 and p27 assessed by quantitative polymerase chain reaction. Immunofluorescence

  2. Wogonin induces apoptosis by suppressing E6 and E7 expressions and activating intrinsic signaling pathways in HPV-16 cervical cancer cells.

    Science.gov (United States)

    Kim, Man Sub; Bak, Yesol; Park, Yun Sun; Lee, Dong Hun; Kim, Jung Hee; Kang, Jeong Woo; Song, Hyuk-Hwan; Oh, Sei-Ryang; Yoon, Do Young

    2013-08-01

    Wogonin is a flavonoid compound extracted from Scutellaria baicalensis and is well known as a benzodiazepine receptor ligand with anxiolytic effects. Many recent studies have demonstrated that wogonin modulates angiogenesis, proliferation, invasion, and tumor progress in various cancer tissues. We further explored the mechanism of action of wogonin on cervical cancer cells that contain or lack human papillomavirus (HPV) DNA. Wogonin was cytotoxic to HPV 16 (+) cervical cancer cells, SiHa and CaSki, but not to HPV-negative cells. We demonstrated that wogonin induced apoptosis by suppressing the expressions of the E6 and E7 viral oncogenes in HPV-infected cervical cancer CaSki and SiHa cells. The modulation of p53 and protein retinoblastoma (pRb) were also triggered by the suppression of E6 and E7 expressions. However, p53 was not altered in HPV-negative cervical cancer C33A cells. Moreover, wogonin modulated the mitochondrial membrane potential and the expression of pro- and anti-apoptotic factors such as Bax and Bcl-2. Wogonin also provoked the cleavage of caspase-3, caspase-9, and poly ADP ribose polymerase. After transfection of siRNAs to target E6 and E7, additional restoration of p53 and pRb was not induced, but processing of caspases and PARP was increased compared with wogonin treatment alone. Together, our findings demonstrated that wogonin effectively promotes apoptosis by downregulating E6 and E7 expressions and promoting intrinsic apoptosis in human cervical cancer cells.

  3. Intrinsic Peroxidase-like Activity of Ficin

    Science.gov (United States)

    Yang, Yufang; Shen, Dongjun; Long, Yijuan; Xie, Zhixiong; Zheng, Huzhi

    2017-02-01

    Ficin is classified as a sulfhydryl protease isolated from the latex of fig trees. In most cases, a particular enzyme fits a few types of substrate and catalyzes one type of reaction. In this investigation, we found sufficient proofs for the intrinsic peroxidase-like activity of ficin and designed experiments to examine its effectiveness in a variety of scenarios. Ficin can transform peroxidase substrates to colored products in the existence of H2O2. Our results also indicate that the active sites of peroxidase-like activity of ficin are different from that of protease, which reveals that one enzyme may catalyze more than one kind of substrate to perform different types of reactions. On the basis of these findings, H2O2 releasing from MCF-7 cells was detected successfully. Our findings support a wider application of ficin in biochemistry and open up the possibility of utilizing ficin as enzymatic mimics in biotechnology and environmental monitoring.

  4. A Schiff base-derived copper (II) complex is a potent inducer of apoptosis in colon cancer cells by activating the intrinsic pathway.

    Science.gov (United States)

    Hajrezaie, Maryam; Paydar, Mohammadjavad; Moghadamtousi, Soheil Zorofchian; Hassandarvish, Pouya; Gwaram, Nura Suleiman; Zahedifard, Maryam; Rouhollahi, Elham; Karimian, Hamed; Looi, Chung Yeng; Ali, Hapipah Mohd; Abdul Majid, Nazia; Abdulla, Mahmood Ameen

    2014-01-01

    Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II) complex on HT-29 colon cancer cells. The Cu(BrHAP)2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87  μg/ml after 72 h of treatment. HT-29 cells treated with Cu (II) complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25  μg/ml, the Cu(BrHAP)2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II) complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP)2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.

  5. A Schiff Base-Derived Copper (II Complex Is a Potent Inducer of Apoptosis in Colon Cancer Cells by Activating the Intrinsic Pathway

    Directory of Open Access Journals (Sweden)

    Maryam Hajrezaie

    2014-01-01

    Full Text Available Metal-based drugs with extensive clinical applications hold great promise for the development of cancer chemotherapeutic agents. In the last few decades, Schiff bases and their complexes have become well known for their extensive biological potential. In the present study, we examined the antiproliferative effect of a copper (II complex on HT-29 colon cancer cells. The Cu(BrHAP2 Schiff base compound demonstrated a potent antiproliferative effect in HT-29 cells, with an IC50 value of 2.87 μg/ml after 72 h of treatment. HT-29 cells treated with Cu (II complexes underwent apoptosis death, as exhibited by a progressive elevation in the proportion of the G1 cell population. At a concentration of 6.25 μg/ml, the Cu(BrHAP2 compound caused significant elevation in ROS production following perturbation of mitochondrial membrane potential and cytochrome c release, as assessed by the measurement of fluorescence intensity in stained cells. Furthermore, the activation of caspases 3/7 and 9 was part of the Cu (II complex-induced apoptosis, which confirmed the involvement of mitochondrial-mediated apoptosis. Meanwhile, there was no significant activation of caspase-8. Taken together, these results imply that the Cu(BrHAP2 compound is a potential candidate for further in vivo and clinical colon cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.

  6. Kelussia odoratissima Mozaff. activates intrinsic pathway of apoptosis in breast cancer cells associated with S phase cell cycle arrest via involvement of p21/p27 in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Karimian H

    2017-02-01

    Full Text Available Hamed Karimian,1 Aditya Arya,2 Mehran Fadaeinasab,3 Mahboubeh Razavi,1 Maryam Hajrezaei,4 Ataul Karim Khan,1 Hapipah Mohd Ali,3 Mahmood Ameen Abdulla,4 Mohamad Ibrahim Noordin1,5 1Department of Pharmacy, Faculty of Medicine, University of Malaya, Kuala Lumpur, 2School of Medicine, Taylor’s University, Subang Jaya, 3Centre for Natural Products Research and Drug Discovery, 4Department of Biomedical Science, Faculty of Medicine, University of Malaya, Kuala Lumpur, 5Malaysian Institute of Pharmaceuticals and Nutraceuticals (IPharm, Pulau Pinang, Malaysia Background: The aim of this study was to evaluate the anticancer potential of Kelussia odoratissima. Several in vitro and in vivo biological assays were applied to explore the direct effect of an extract and bioactive compound of this plant against breast cancer cells and its possible mechanism of action. Materials and methods: K. odoratissima methanol extract (KME was prepared, and MTT assay was used to evaluate the cytotoxicity. To identify the cytotoxic compound, a bioassay-guided investigation was performed on methanol extract. 8-Hydroxy-ar-turmerone was isolated as a bioactive compound. In vivo study was performed in the breast cancer rat model. LA7 cell line was used to induce the breast tumor. Histopathological and expression changes of PCNA, Bcl-2, Bax, p27 and p21 and caspase-3 were examined. The induction of apoptosis was tested using Annexin V-fluorescein isothiocyanate (FITC assay. To confirm the intrinsic pathway of apoptosis, caspase-7 and caspase-9 assays were utilized. In addition, cell cycle arrest was evaluated. Results: Our results demonstrated that K. odoratissima has an obvious effect on the arrest of proliferation of cancer cells. It induced apoptosis, transduced the cell death signals, decreased the threshold of mitochondrial membrane potential (MMP, upregulated Bax and downregulated Bcl-2. Conclusion: This study demonstrated that K. odoratissima exhibits antitumor activity

  7. Kelussia odoratissima Mozaff. activates intrinsic pathway of apoptosis in breast cancer cells associated with S phase cell cycle arrest via involvement of p21/p27 in vitro and in vivo

    Science.gov (United States)

    Karimian, Hamed; Arya, Aditya; Fadaeinasab, Mehran; Razavi, Mahboubeh; Hajrezaei, Maryam; Karim Khan, Ataul; Mohd Ali, Hapipah; Abdulla, Mahmood Ameen; Noordin, Mohamad Ibrahim

    2017-01-01

    Background The aim of this study was to evaluate the anticancer potential of Kelussia odoratissima. Several in vitro and in vivo biological assays were applied to explore the direct effect of an extract and bioactive compound of this plant against breast cancer cells and its possible mechanism of action. Materials and methods K. odoratissima methanol extract (KME) was prepared, and MTT assay was used to evaluate the cytotoxicity. To identify the cytotoxic compound, a bioassay-guided investigation was performed on methanol extract. 8-Hydroxy-ar-turmerone was isolated as a bioactive compound. In vivo study was performed in the breast cancer rat model. LA7 cell line was used to induce the breast tumor. Histopathological and expression changes of PCNA, Bcl-2, Bax, p27 and p21 and caspase-3 were examined. The induction of apoptosis was tested using Annexin V-fluorescein isothiocyanate (FITC) assay. To confirm the intrinsic pathway of apoptosis, caspase-7 and caspase-9 assays were utilized. In addition, cell cycle arrest was evaluated. Results Our results demonstrated that K. odoratissima has an obvious effect on the arrest of proliferation of cancer cells. It induced apoptosis, transduced the cell death signals, decreased the threshold of mitochondrial membrane potential (MMP), upregulated Bax and downregulated Bcl-2. Conclusion This study demonstrated that K. odoratissima exhibits antitumor activity against breast cancer cells via cell death and cell cycle arrest. PMID:28203057

  8. Dihydroartemisinin induces apoptosis preferentially via a Bim-mediated intrinsic pathway in hepatocarcinoma cells.

    Science.gov (United States)

    Qin, Guiqi; Zhao, ChuBiao; Zhang, Lili; Liu, Hongyu; Quan, Yingyao; Chai, Liuying; Wu, Shengnan; Wang, Xiaoping; Chen, Tongsheng

    2015-08-01

    This report is designed to dissect the detail molecular mechanism by which dihydroartemisinin (DHA), a derivative of artemisinin, induces apoptosis in human hepatocellular carcinoma (HCC) cells. DHA induced a loss of the mitochondrial transmemberane potential (ΔΨm), release of cytochrome c, activation of caspases, and externalization of phosphatidylserine indicative of apoptosis induction. Compared with the modest inhibitory effects of silencing Bax, silencing Bak largely prevented DHA-induced ΔΨm collapse and apoptosis though DHA induced a commensurable activation of Bax and Bak, demonstrating a key role of the Bak-mediated intrinsic apoptosis pathway. DHA did not induce Bid cleavage and translocation from cytoplasm to mitochondria and had little effects on the expressions of Puma and Noxa, but did increase Bim and Bak expressions and decrease Mcl-1 expression. Furthermore, the cytotoxicity of DHA was remarkably reduced by silencing Bim, and modestly but significantly reduced by silencing Puma or Noxa. Silencing Bim or Noxa preferentially reduced DHA-induced Bak activation, while silencing Puma preferentially reduced DHA-induced Bax activation, demonstrating that Bim and to a lesser extent Noxa act as upstream mediators to trigger the Bak-mediated intrinsic apoptosis pathway. In addition, silencing Mcl-1 enhanced DHA-induced Bak activation and apoptosis. Taken together, our data demonstrate a crucial role of Bim in preferentially regulating the Bak/Mcl-1 rheostat to mediate DHA-induced apoptosis in HCC cells.

  9. Intrinsic apoptotic pathways of gingival epithelial cells modulated by Porphyromonas gingivalis.

    Science.gov (United States)

    Mao, Song; Park, Yoonsuk; Hasegawa, Yoshiaki; Tribble, Gena D; James, Chlöe E; Handfield, Martin; Stavropoulos, M Franci; Yilmaz, Ozlem; Lamont, Richard J

    2007-08-01

    Porphyromonas gingivalis can inhibit chemically induced apoptosis in primary cultures of gingival epithelial cells through blocking activation of the effector caspase-3. The anti-apoptotic phenotype of P. gingivalis is conserved across strains and does not depend on the presence of fimbriae, as fimbriae-deficient mutants and a naturally occurring non-fimbriated strain were able to impede apoptosis. To dissect the survival pathways modulated by P. gingivalis, protein and gene expression of a number of components of apoptotic death pathways were investigated. P. gingivalis infection of epithelial cells resulted in the phosphorylation of JAK1 and Stat3. Quantitative real-time reverse transcription polymerase chain reaction showed that expression of Survivin and Stat3 itself, targets of activated Stat3, were elevated in P. gingivalis-infected cells. siRNA knockdown of JAK1, in combination with knockdown of Akt, abrogated the ability of P. gingivalis to block apoptosis. In contrast, cIAP-1 and cIAP-2 were not differentially regulated at either the protein or mRNA levels by P. gingivalis. One mechanism by which P. gingivalis can block apoptotic pathways in gingival epithelial cells therefore is through manipulation of the JAK/Stat pathway that controls the intrinsic mitochondrial cell death pathways. Induction of a pro-survival phenotype may prevent programmed host cell death and aid survival of P. gingivalis within gingival epithelial cells.

  10. Longitudinal Pathways from Math Intrinsic Motivation and Achievement to Math Course Accomplishments and Educational Attainment

    Science.gov (United States)

    Gottfried, Adele Eskeles; Marcoulides, George A.; Gottfried, Allen W.; Oliver, Pamella H.

    2013-01-01

    Across 20 years, pathways from math intrinsic motivation and achievement (ages 9-17) to high school math course accomplishments and educational attainment (age 29) were analyzed. Academic intrinsic motivation was the theoretical foundation. To determine how initial status and change in motivation and achievement related to course accomplishments…

  11. A BAX/BAK and cyclophilin D-independent intrinsic apoptosis pathway.

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    Sebastián Zamorano

    Full Text Available Most intrinsic death signals converge into the activation of pro-apoptotic BCL-2 family members BAX and BAK at the mitochondria, resulting in the release of cytochrome c and apoptosome activation. Chronic endoplasmic reticulum (ER stress leads to apoptosis through the upregulation of a subset of pro-apoptotic BH3-only proteins, activating BAX and BAK at the mitochondria. Here we provide evidence indicating that the full resistance of BAX and BAK double deficient (DKO cells to ER stress is reverted by stimulation in combination with mild serum withdrawal. Cell death under these conditions was characterized by the appearance of classical apoptosis markers, caspase-9 activation, release of cytochrome c, and was inhibited by knocking down caspase-9, but insensitive to BCL-X(L overexpression. Similarly, the resistance of BIM and PUMA double deficient cells to ER stress was reverted by mild serum withdrawal. Surprisingly, BAX/BAK-independent cell death did not require Cyclophilin D (CypD expression, an important regulator of the mitochondrial permeability transition pore. Our results suggest the existence of an alternative intrinsic apoptosis pathway emerging from a cross talk between the ER and the mitochondria.

  12. Intrinsic and extrinsic pathway signaling during neuronal apoptosis: lessons from the analysis of mutant mice.

    Science.gov (United States)

    Putcha, Girish V; Harris, Charles A; Moulder, Krista L; Easton, Rachael M; Thompson, Craig B; Johnson, Eugene M

    2002-04-29

    Trophic factor deprivation (TFD)-induced apoptosis in sympathetic neurons requires macromolecular synthesis-dependent BAX translocation, cytochrome c (cyt c) release, and caspase activation. Here, we report the contributions of other intrinsic and extrinsic pathway signals to these processes. Sympathetic neurons expressed all antiapoptotic BCL-2 proteins examined, yet expressed only certain BH3-only and multidomain proapoptotic BCL-2 family members. All coexpressed proapoptotic proteins did not, however, exhibit functional redundancy or compensatory expression, at least in the Bax-/-, Bak-/-, Bim-/-, Bid-/-, and Bad-/- neurons examined. Although the subcellular distribution or posttranslational modification of certain BCL-2 proteins changed with TFD, neither transcriptional nor posttranslational mechanisms regulated the expression or subcellular localization of BID, BAD, or BAK in this paradigm. Despite modest induction of Fas and FasL expression, Fas-mediated signaling did not contribute to TFD-induced apoptosis in sympathetic neurons. Similar findings were obtained with K+ withdrawal-induced apoptosis in cerebellar granule neurons, a model for activity-dependent neuronal survival in the CNS. Thus, expression alone does not guarantee functional redundancy (or compensation) among BCL-2 family members, and, at least in some cells, extrinsic pathway signaling and certain BH3-only proteins (i.e., BID and BAD) do not contribute to BAX-dependent cyt c release or apoptosis caused by TFD.

  13. Induction of intrinsic and extrinsic apoptosis pathways in the human leukemic MOLT-4 cell line by terpinen-4-ol.

    Science.gov (United States)

    Khaw-on, Patompong; Banjerdpongchai, Ratana

    2012-01-01

    Terpinen-4-ol is a terpene found in the rhizome of Plai (Zingiber montanum (Koenig) Link ex Dietr.). In this study apoptogenic activity and mechanisms of cell death induced by terpinen-4-ol were investigated in the human leukemic MOLT-4 cell line. Terpinen-4-ol exhibited cytotoxicity in MOLT-4 cells, with characteristic morphological features of apoptosis by Wright's staining. The mode of cell death was confirmed to be apoptosis by flow cytometric analysis after staining with annexin V-FITC and propidium iodide. A sub-G1 peak in DNA histograms of cell cycle assays was observed. Terpinen-4-ol induced-MOLT-4 cell apoptosis mediated through an intrinsic pathway involving the loss of mitochondrial transmembrane potential (MTP) and release of cytochrome c into the cytosol. In addition, terpinen-4-ol also induced apoptosis via an extrinsic pathway by caspase-8 activation resulting in the cleavage of cytosolic Bid. Truncated-Bid (tBid) translocated to mitochondria and activated the mitochondrial pathway in conjunction with down-regulation of Bcl-2 protein expression. Caspase-3 activity also increased. In conclusion, terpinen-4-ol can induce human leukemic MOLT-4 cell apoptosis via both intrinsic and extrinsic pathways.

  14. Chalcone-Induced Apoptosis through Caspase-Dependent Intrinsic Pathways in Human Hepatocellular Carcinoma Cells

    Science.gov (United States)

    Ramirez-Tagle, Rodrigo; Escobar, Carlos A.; Romero, Valentina; Montorfano, Ignacio; Armisén, Ricardo; Borgna, Vincenzo; Jeldes, Emanuel; Pizarro, Luis; Simon, Felipe; Echeverria, Cesar

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers worldwide. Chemoprevention of HCC can be achieved through the use of natural or synthetic compounds that reverse, suppress or prevent the development of cancer progression. In this study, we investigated the antiproliferative effects and the mechanism of action of two compounds, 2,3,4′-trimethoxy-2′-hydroxy-chalcone (CH1) and 3′-bromo-3,4-dimethoxy-chalcone (CH2), over human hepatoma cells (HepG2 and Huh-7) and cultured mouse hepatocytes (HepM). Cytotoxic effects were observed over the HepG2 and Huh-7, and no effects were observed over the HepM. For HepG2 cells, treated separately with each chalcone, typical apoptotic laddering and nuclear condensation were observed. Additionally, the caspases and Bcl-2 family proteins activation by using Western blotting and immunocytochemistry were studied. Caspase-8 was not activated, but caspase-3 and -9 were both activated by chalcones in HepG2 cells. Chalcones also induced reactive oxygen species (ROS) accumulation after 4, 8 and 24 h of treatment in HepG2 cells. These results suggest that apoptosis in HepG2 was induced through: (i) a caspase-dependent intrinsic pathway; and (ii) by alterations in the cellular levels of Bcl-2 family proteins, and also, that the chalcone moiety could be a potent candidate as novel anticancer agents acting on human hepatomas. PMID:26907262

  15. Chalcone-Induced Apoptosis through Caspase-Dependent Intrinsic Pathways in Human Hepatocellular Carcinoma Cells.

    Science.gov (United States)

    Ramirez-Tagle, Rodrigo; Escobar, Carlos A; Romero, Valentina; Montorfano, Ignacio; Armisén, Ricardo; Borgna, Vincenzo; Jeldes, Emanuel; Pizarro, Luis; Simon, Felipe; Echeverria, Cesar

    2016-02-22

    Hepatocellular carcinoma (HCC) is one of the most commonly diagnosed cancers worldwide. Chemoprevention of HCC can be achieved through the use of natural or synthetic compounds that reverse, suppress or prevent the development of cancer progression. In this study, we investigated the antiproliferative effects and the mechanism of action of two compounds, 2,3,4'-trimethoxy-2'-hydroxy-chalcone (CH1) and 3'-bromo-3,4-dimethoxy-chalcone (CH2), over human hepatoma cells (HepG2 and Huh-7) and cultured mouse hepatocytes (HepM). Cytotoxic effects were observed over the HepG2 and Huh-7, and no effects were observed over the HepM. For HepG2 cells, treated separately with each chalcone, typical apoptotic laddering and nuclear condensation were observed. Additionally, the caspases and Bcl-2 family proteins activation by using Western blotting and immunocytochemistry were studied. Caspase-8 was not activated, but caspase-3 and -9 were both activated by chalcones in HepG2 cells. Chalcones also induced reactive oxygen species (ROS) accumulation after 4, 8 and 24 h of treatment in HepG2 cells. These results suggest that apoptosis in HepG2 was induced through: (i) a caspase-dependent intrinsic pathway; and (ii) by alterations in the cellular levels of Bcl-2 family proteins, and also, that the chalcone moiety could be a potent candidate as novel anticancer agents acting on human hepatomas.

  16. Chalcone-Induced Apoptosis through Caspase-Dependent Intrinsic Pathways in Human Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Rodrigo Ramirez-Tagle

    2016-02-01

    Full Text Available Hepatocellular carcinoma (HCC is one of the most commonly diagnosed cancers worldwide. Chemoprevention of HCC can be achieved through the use of natural or synthetic compounds that reverse, suppress or prevent the development of cancer progression. In this study, we investigated the antiproliferative effects and the mechanism of action of two compounds, 2,3,4′-trimethoxy-2′-hydroxy-chalcone (CH1 and 3′-bromo-3,4-dimethoxy-chalcone (CH2, over human hepatoma cells (HepG2 and Huh-7 and cultured mouse hepatocytes (HepM. Cytotoxic effects were observed over the HepG2 and Huh-7, and no effects were observed over the HepM. For HepG2 cells, treated separately with each chalcone, typical apoptotic laddering and nuclear condensation were observed. Additionally, the caspases and Bcl-2 family proteins activation by using Western blotting and immunocytochemistry were studied. Caspase-8 was not activated, but caspase-3 and -9 were both activated by chalcones in HepG2 cells. Chalcones also induced reactive oxygen species (ROS accumulation after 4, 8 and 24 h of treatment in HepG2 cells. These results suggest that apoptosis in HepG2 was induced through: (i a caspase-dependent intrinsic pathway; and (ii by alterations in the cellular levels of Bcl-2 family proteins, and also, that the chalcone moiety could be a potent candidate as novel anticancer agents acting on human hepatomas.

  17. miR-24 regulates intrinsic apoptosis pathway in mouse cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Numerous cardiac diseases, including myocardial infarction (MI and chronic heart failure, have been associated with cardiomyocyte apoptosis. Promoting cell survival by inhibiting apoptosis is one of the effective strategies to attenuate cardiac dysfunction caused by cardiomyocyte loss. miR-24 has been shown as an anti-apoptotic microRNA in various animal models. In vivo delivery of miR-24 into a mouse MI model suppressed cardiac cell death, attenuated infarct size, and rescued cardiac dysfunction. However, the molecular pathway by which miR-24 inhibits cardiomyocyte apoptosis is not known. Here we found that miR-24 negatively regulates mouse primary cadiomyocyte cell death through functioning in the intrinsic apoptotic pathways. In ER-mediated intrinsic pathway, miR-24 genetically interacts with the CEBP homologous gene CHOP as knocking down of CHOP partially attenuated the induced apoptosis by miR-24 inhibition. In mitochondria-involved intrinsic pathway, miR-24 inhibits the initiation of apoptosis through suppression of Cytochrome C release and Bax translocation from cytosol to mitochondria. These results provide mechanistic insights into the miR-24 mediated anti-apoptotic effects in murine cardiomyocytes.

  18. Angelica polymorpha Maxim Induces Apoptosis of Human SH-SY5Y Neuroblastoma Cells by Regulating an Intrinsic Caspase Pathway.

    Science.gov (United States)

    Rahman, Md Ataur; Bishayee, Kausik; Huh, Sung-Oh

    2016-02-01

    Angelica polymorpha Maxim root extract (APRE) is a popular herbal medicine used for treating stomachache, abdominal pain, stomach ulcers, and rheumatism; however the effect of APRE on cancer cells has not yet been explored. Here, we examined APRE cytotoxicity seen on target neuroblastoma cells (NB) using cell viability assays, DAPI visualization of fragmented DNA, and Western blotting analysis of candidate signaling pathways involved in proliferation and apoptosis. We demonstrated that APRE reduced cell viability in NB to a greater extent than in fibroblast cells. In addition, we found that APRE could inhibit the three classes of MAPK proteins and could also down-regulate the PI3K/AKT/GSK-3β activity all being relevant for proliferation and survival. APRE could also up-regulate Bax expression and down-regulate Bcl-2 and Mcl-1. With APRE treatment, depolarization of mitochondria membrane potential and activation of caspase-3 was demonstrated in the SH-SY5Y cells. We could not found increased activity of death receptor and caspase-8 as markers of the extrinsic apoptosis pathway for the APRE treated cells. In presence of a caspase-3 siRNA and a pan-caspase inhibitor, APRE could not reduce the viability of NB cells to a significant degree. So we predicted that with APRE, the intrinsic pathway was solely responsible for inducing apoptosis as we also showed that the non-caspase autophagy pathway or ER stress-ROS mediated pathways were not involved. These findings demonstrate that an intrinsic mitochondria-mediated apoptosis pathway mediates the apoptotic effects of APRE on SH-SY5Y cells, and that APRE shows promise as a novel agent for neuroblastoma therapy.

  19. Focal pontine lesions provide evidence that intrinsic functional connectivity reflects polysynaptic anatomical pathways.

    Science.gov (United States)

    Lu, Jie; Liu, Hesheng; Zhang, Miao; Wang, Danhong; Cao, Yanxiang; Ma, Qingfeng; Rong, Dongdong; Wang, Xiaoyi; Buckner, Randy L; Li, Kuncheng

    2011-10-19

    Intrinsic functional connectivity detected by functional MRI (fMRI) provides a useful but indirect approach to study the organization of human brain systems. An unresolved question is whether functional connectivity measured by resting-state fMRI reflects anatomical connections. In this study, we used the well-characterized anatomy of cerebrocerebellar circuits to directly test whether intrinsic functional connectivity is associated with an anatomic pathway. Eleven first-episode stroke patients were scanned five times during a period of 6 months, and 11 healthy control subjects were scanned three times within 1 month. In patients with right pontine strokes, the functional connectivity between the right motor cortex and the left cerebellum was selectively reduced. This connectivity pattern was reversed in patients with left pontine strokes. Although factors beyond anatomical connectivity contribute to fMRI measures of functional correlation, these results provide direct evidence that functional connectivity depends on intact connections within a specific polysynaptic pathway.

  20. A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed

    OpenAIRE

    Rahul Palchaudhuri; Michael J. Lambrecht; Rachel C. Botham; Kathryn C. Partlow; Tjakko J. van Ham; Karson S. Putt; Laurie T. Nguyen; Seok-Ho Kim; Randall T. Peterson; Timothy M. Fan; Paul J. Hergenrother

    2015-01-01

    textabstractApoptosis is generally believed to be a process thatrequires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, named Raptinal, which initiates intrinsic pathway caspase-dependent apoptosis within minutes in multiple cell lines. Comparison to a mechanistically diverse panel of apoptotic stimuli reveals that Ra...

  1. Apigenin induces both intrinsic and extrinsic pathways of apoptosis in human colon carcinoma HCT-116 cells.

    Science.gov (United States)

    Wang, Bo; Zhao, Xin-Huai

    2017-02-01

    Apigenin is one of the plant-originated flavones with anticancer activities. In this study, apigenin was assessed for its in vitro effects on a human colon carcinoma line (HCT‑116 cells) in terms of anti-proliferation, cell cycle progression arrest, apoptosis and intracellular reactive oxygen species (ROS) generation, and then outlined its possible apoptotic mechanism for the cells. Apigenin exerted cytotoxic effect on the cells via inhibiting cell growth in a dose-time-dependent manner and causing morphological changes, arrested cell cycle progression at G0/G1 phase, and decreased mitochondrial membrane potential of the treated cells. Apigenin increased respective ROS generation and Ca2+ release and thereby, caused ER stress in the treated cells. Apigenin shows apoptosis induction towards the cells, resulting in enhanced portion of apoptotic cells. A mechanism involved ROS generation and endoplasmic reticulum stress was outlined for the apigenin-mediated apoptosis via both intrinsic mitochondrial and extrinsic pathways, based on the assayed mRNA and protein expression levels in the cells. With this mechanism, apigenin resulted in the HCT-116 cells with enhanced intracellular ROS generation and Ca2+ release together with damaged mitochondrial membrane, and upregulated protein expression of CHOP, DR5, cleaved BID, Bax, cytochrome c, cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9, which triggered apoptosis of the cells.

  2. High-molecular-weight kininogen and the intrinsic coagulation pathway in patients with de novo acute myocardial infarction.

    Science.gov (United States)

    Cubedo, Judit; Ramaiola, Ilaria; Padró, Teresa; Martin-Yuste, Victoria; Sabate-Tenas, Manel; Badimon, Lina

    2013-12-01

    After an acute ischaemic event serum proteins may change reflecting the ischaemic damage. Proteomic studies could provide new insights into potential biomarkers in the evolution of ischaemic syndromes. In this study we have investigated the coordinated changes in coagulation-related proteins in the evolution after an acute myocardial infarction (AMI). Serum proteome (2D-electrophoresis and MALDI-TOF/TOF) of AMI-patients within the first 6 hours after event onset (admission-time) and 3 days after were compared to controls. Systems biology and bioinformatic analysis were performed to identify the differentially expressed canonical pathways. In silico analysis of differential proteins revealed changes in the intrinsic coagulation pathway in the early phase post-AMI. The two identified high-molecular weight kininogen (HMWK) clusters were inversely correlated in AMI patients at admission, being the intensity of the low-molecular-weight form inversely related to myocardial necrosis (pfibrinogen gamma and D-dimer at admission, followed by a decrease in fibrinogen turnover 3 days after (pfibrinogen distribution changes was validated in coronary thrombi retrieved by thromboaspiration. In conclusion, our results demonstrate an active exchange between HMWK forms and a decrease in FXI indicative of intrinsic pathway activation, together with an increase in fibrinogen gamma turnover and D-dimer formation in the early phase post-AMI. Moreover, coronary thrombi showed a dynamic evolution in fibrinogen composition depending on the duration of ischaemia influencing serum fibrinogen-related products content.

  3. Solanum lyratum Extracts Induce Extrinsic and Intrinsic Pathways of Apoptosis in WEHI-3 Murine Leukemia Cells and Inhibit Allograft Tumor

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    Jai-Sing Yang

    2012-01-01

    Full Text Available We investigated the molecular mechanisms of cell cycle arrest and apoptotic death induced by Solanum lyratum extracts (SLE or diosgenin in WEHI-3 murine leukemia cells in vitro and antitumor activity in vivo. Diosgenin is one of the components of SLE. Our study showed that SLE and diosgenin decreased the viable WEHI-3 cells and induced G0/G1 phase arrest and apoptosis in concentration- or time-dependent manners. Both reagents increased the levels of ROS production and decreased the mitochondrial membrane potential (ΔΨm. SLE- and diosgenin-triggered apoptosis is mediated through modulating the extrinsic and intrinsic signaling pathways. Intriguingly, the p53 inhibitor (pifithrin-α, anti-Fas ligand (FasL mAb, and specific inhibitors of caspase-8 (z-IETD-fmk, caspase-9 (z-LEHD-fmk, and caspase-3 (z-DEVD-fmk blocked SLE- and diosgenin-reduced cell viability of WEHI-3 cells. The in vivo study demonstrated that SLE has marked antitumor efficacy against tumors in the WEHI-3 cell allograft model. In conclusion, SLE- and diosgenin-induced G0/G1 phase arrest and triggered extrinsic and intrinsic apoptotic pathways via p53 activation in WEHI-3 cells. SLE also exhibited antitumor activity in vivo. Our findings showed that SLE may be potentially efficacious in the treatment of leukemia in the future.

  4. Older adults' intrinsic and extrinsic motivation toward physical activity.

    Science.gov (United States)

    Dacey, Marie; Baltzell, Amy; Zaichkowsky, Len

    2008-01-01

    To examine how motives discriminate 3 physical activity levels of inactive, active, and sustained maintainers. Six hundred forty-five adults (M age = 63.8) completed stage-of-change and Exercise Motivations Inventory (EMI-2) scales. Exploratory factor analysis established psychometric properties of the EMI-2 suitable for older adults. Six factors emerged in the EMI-2: health and fitness, social/emotional benefits, weight management, stress management, enjoyment, and appearance. Enjoyment contributed most to differentiating activity levels. Moderators of age and gender were delineated. Intrinsic motivation and self-determined extrinsic motivation distinguish older adults' activity levels.

  5. Combination of extrinsic and intrinsic pathways significantly accelerates axial vascularization of bioartificial tissues.

    Science.gov (United States)

    Arkudas, Andreas; Pryymachuk, Galyna; Beier, Justus P; Weigel, Linda; Körner, Carolin; Singer, Robert F; Bleiziffer, Oliver; Polykandriotis, Elias; Horch, Raymund E; Kneser, Ulrich

    2012-01-01

    In this study, the authors present a modification of the arteriovenous loop model that combines extrinsic and intrinsic vascularization modes to enhance vascularization of bioartificial matrices. An arteriovenous loop was created in the medial thighs of 24 rats. The loop was placed in a newly developed titanium chamber, which was fabricated with an electron beam melting facility, and was embedded in a hydroxyapatite/β-tricalcium phosphate/fibrin matrix. At the explantation time points (2, 4, 6, and 8 weeks), constructs were perfused by differently colored dyes to determine the amount of tissue vascularized by either the intrinsic or the extrinsic vascular pathway. Specimens were investigated by means of micro-computed tomography and histologic and morphometric analysis. Although there was an equal number of blood vessels originating from the center and the periphery, 83 percent of all vessels displayed a connection to the arteriovenous loop already at 2 weeks. There was a continuous increase of the relative proportion of vessels connected to the arteriovenous loop over time detectable. At 8 weeks, communications between the newly formed vessels and the arteriovenous loop were visible in 97 percent of all vessels. This study demonstrates for the first time the enhancement of angiogenesis in an axially vascularized tissue by an additional extrinsic vascular pathway. By 2 weeks, both pathways showed connections, allowing transplantation of the entire construct using the arteriovenous loop pedicle. This approach will allow for reduction of the time interval between arteriovenous loop implantation and transplantation into the defect site and limitation of operative interventions.

  6. Ethyl Pyruvate Ameliorates Hepatic Ischemia-Reperfusion Injury by Inhibiting Intrinsic Pathway of Apoptosis and Autophagy

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    Miao Shen

    2013-01-01

    Full Text Available Background. Hepatic ischemia-reperfusion (I/R injury is a pivotal clinical problem occurring in many clinical conditions such as transplantation, trauma, and hepatic failure after hemorrhagic shock. Apoptosis and autophagy have been shown to contribute to cell death in hepatic I/R injury. Ethyl pyruvate, a stable and simple lipophilic ester, has been shown to have anti-inflammatory properties. In this study, the purpose is to explore both the effect of ethyl pyruvate on hepatic I/R injury and regulation of intrinsic pathway of apoptosis and autophagy. Methods. Three doses of ethyl pyruvate (20 mg/kg, 40 mg/kg, and 80 mg/kg were administered 1 h before a model of segmental (70% hepatic warm ischemia was established in Balb/c mice. All serum and liver tissues were obtained at three different time points (4 h, 8 h, and 16 h. Results. Alanine aminotransferase (ALT, aspartate aminotransferase (AST, and pathological features were significantly ameliorated by ethyl pyruvate (80 mg/kg. The expression of Bcl-2, Bax, Beclin-1, and LC3, which play an important role in the regulation of intrinsic pathway of apoptosis and autophagy, was also obviously decreased by ethyl pyruvate (80 mg/kg. Furthermore, ethyl pyruvate inhibited the HMGB1/TLR4/ NF-κb axis and the release of cytokines (TNF-α and IL-6. Conclusion. Our results showed that ethyl pyruvate might attenuate to hepatic I/R injury by inhibiting intrinsic pathway of apoptosis and autophagy, mediated partly through downregulation of HMGB1/TLR4/ NF-κb axis and the competitive interaction with Beclin-1 of HMGB1.

  7. H2O2 INDUCES APOPTOSIS OF RABBIT CHONDROCYTES VIA BOTH THE EXTRINSIC AND THE CASPASE-INDEPENDENT INTRINSIC PATHWAYS

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    CAIPING ZHUANG

    2013-07-01

    Full Text Available Osteoarthritis (OA, one of the most common joint diseases with unknown etiology, is characterized by the progressive destruction of articular cartilage and the apoptosis of chondrocytes. The purpose of this study is to elucidate the molecular mechanisms of H2O2-mediated rabbit chondrocytes apoptosis. CCK-8 assay showed that H2O2 treatment induced a remarkable reduction of cell viability, which was further verified by the remarkable phosphatidylserine externalization after H2O2 treatment for 1 h, the typical characteristics of apoptosis. H2O2 treatment induced a significant dysfunction of mitochondrial membrane potential (ΔΨm, but did not induce casapse-9 activation, indicating that H2O2 treatment induced caspase-independent intrinsic apoptosis that was further verified by the fact that silencing of AIF but not inhibiting caspase-9 potently prevented H2O2-induced apoptosis. H2O2 treatment induced a significant increase of caspase-8 and -3 activation, and inhibition of caspase-8 or -3 significantly prevented H2O2-induced apoptosis, suggesting that the extrinsic pathway played an important role. Collectively, our findings demonstrate that H2O2 induces apoptosis via both the casapse-8-mediated extrinsic and the caspase-independent intrinsic apoptosis pathways in rabbit chondrocytes.

  8. A small molecule inhibitor partitions two distinct pathways for trafficking of tonoplast intrinsic proteins in Arabidopsis.

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    Efrain E Rivera-Serrano

    Full Text Available Tonoplast intrinsic proteins (TIPs facilitate the membrane transport of water and other small molecules across the plant vacuolar membrane, and members of this family are expressed in specific developmental stages and tissue types. Delivery of TIP proteins to the tonoplast is thought to occur by vesicle-mediated traffic from the endoplasmic reticulum to the vacuole, and at least two pathways have been proposed, one that is Golgi-dependent and another that is Golgi-independent. However, the mechanisms for trafficking of vacuolar membrane proteins to the tonoplast remain poorly understood. Here we describe a chemical genetic approach to unravel the mechanisms of TIP protein targeting to the vacuole in Arabidopsis seedlings. We show that members of the TIP family are targeted to the vacuole via at least two distinct pathways, and we characterize the bioactivity of a novel inhibitor that can differentiate between them. We demonstrate that, unlike for TIP1;1, trafficking of markers for TIP3;1 and TIP2;1 is insensitive to Brefeldin A in Arabidopsis hypocotyls. Using a chemical inhibitor that may target this BFA-insensitive pathway for membrane proteins, we show that inhibition of this pathway results in impaired root hair growth and enhanced vacuolar targeting of the auxin efflux carrier PIN2 in the dark. Our results indicate that the vacuolar targeting of PIN2 and the BFA-insensitive pathway for tonoplast proteins may be mediated in part by common mechanisms.

  9. Robust Active Binocular Vision through Intrinsically Motivated Learning

    Directory of Open Access Journals (Sweden)

    Luca eLonini

    2013-11-01

    Full Text Available The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a binocular vision system implemented on a robot. Robustness is an important aspect that reflects the ability of the system to deal with unmodeled disturbances or events, such as an insult to the system that displace the stereo cameras. To demonstrate the robustness of our method and its ability to self-calibrate, we introduce various perturbations and test if and how the system recovers from them. We find that 1 the system can fully recover from a perturbation that can be compensated through the system's motor degrees of freedom, 2 performance degrades gracefully if the system cannot use its motor degrees of freedom to compensate for the perturbation, and 3 recovery from a perturbation is improved if both the sensory encoding and the behavior policy can adapt to the perturbation. Overall, this work demonstrates that our intrinsically motivated learning approach for efficient coding in active perception gives rise to a self-calibrating perceptual system of high robustness.

  10. Robust active binocular vision through intrinsically motivated learning.

    Science.gov (United States)

    Lonini, Luca; Forestier, Sébastien; Teulière, Céline; Zhao, Yu; Shi, Bertram E; Triesch, Jochen

    2013-01-01

    The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a binocular vision system implemented on a robot. Robustness is an important aspect that reflects the ability of the system to deal with unmodeled disturbances or events, such as insults to the system that displace the stereo cameras. To demonstrate the robustness of our method and its ability to self-calibrate, we introduce various perturbations and test if and how the system recovers from them. We find that (1) the system can fully recover from a perturbation that can be compensated through the system's motor degrees of freedom, (2) performance degrades gracefully if the system cannot use its motor degrees of freedom to compensate for the perturbation, and (3) recovery from a perturbation is improved if both the sensory encoding and the behavior policy can adapt to the perturbation. Overall, this work demonstrates that our intrinsically motivated learning approach for efficient coding in active perception gives rise to a self-calibrating perceptual system of high robustness.

  11. Biocompatibility selenium nanoparticles with an intrinsic oxidase-like activity

    Science.gov (United States)

    Guo, Leilei; Huang, Kaixun; Liu, Hongmei

    2016-03-01

    Selenium nanoparticles (SeNPs) are considered to be the new selenium supplement forms with high biological activity and low toxicity; however, the molecular mechanism by which SeNPs exert the biological function is unclear. Here, we reported that biocompatibility SeNPs possessed intrinsic oxidase-like activity. Using Na2SeO3 as a precursor and glutathione as a reductant, biocompatibility SeNPs were synthesized by the wet chemical reduction method in the presence of bovine serum albumin (BSA). The results of structure characterization revealed that synthesized SeNPs were amorphous red elementary selenium with spherical morphology, and ranged in size from 25 to 70 nm size with a narrow distribution (41.4 ± 6.7 nm). The oxidase-like activity of the as-synthesized SeNPs was tested with 3,3',5,5'-tetramethylbenzidine (TMB) as a substrate. The results indicated that SeNPs could catalyze the oxidization of TMB by dissolved oxygen. These SeNPs showed an optimum catalytic activity at pH 4 and 30 °C, and the oxidase-like activity was higher as the concentration of SeNPs increased and the size of SeNPs decreased. The Michaelis constant ( K m) values and maximal reaction velocity ( V max) of the SeNPs for TMB oxidation were 0.0083 mol/L and 3.042 μmol/L min, respectively.

  12. Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

    Science.gov (United States)

    Gao, Lizeng; Zhuang, Jie; Nie, Leng; Zhang, Jinbin; Zhang, Yu; Gu, Ning; Wang, Taihong; Feng, Jing; Yang, Dongling; Perrett, Sarah; Yan, Xiyun

    2007-09-01

    Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

  13. Parathyroid hormone related protein (PTHrP) inhibits TNFalpha-induced apoptosis by blocking the extrinsic and intrinsic pathways.

    Science.gov (United States)

    Okoumassoun, Liliane; Averill-Bates, Diana; Denizeau, Francine; Henderson, Janet E

    2007-02-01

    Parathyroid hormone related protein (PTHrP) is expressed at low levels in many fetal and adult tissues where it plays a central role in regulating cell proliferation, cell death, and tissue homeostasis. In vivo and in vitro, PTHrP has been shown to promote the survival of a variety of cells by regulating expression of the anti-apoptotic protein Bcl2. Additional work has shown that intra-nuclear accumulation of PTHrP in CFK2 (PTH1R positive) and 27m21 (PTH1R negative) condrogenic cells promotes their survival by closing down ribosome biogenesis and promoting quiescence. The current studies were undertaken to examine the role of wild-type PTHrP and a mutant form that cannot translocate to the nucleus in protecting cells from TNFalpha-induced apoptosis. Both forms of the protein were equally effective in blocking the extrinsic pathway by inhibiting expression of the TNF receptor death domain, activating Bid, and promoting cleavage of caspase 8. These observations suggest a direct mechanism of PTHrP action on components of the extrinsic pathway, involving a region of the protein outside of the NTS. PTHrP and M1PTHrP also inhibited the intrinsic pathway by preventing the exchange of anti-apoptotic for pro-apoptotic proteins at the mitochondrial membrane, thus maintaining its integrity and preventing the release of caspase-activating factors into the cytosol. In general, this mitochondrial-related activity was somewhat delayed and was mediated more effectively by PTHrP than by M1PTHrP, suggesting an indirect mechanism of action that might require the presence of an intact NTS.

  14. Activations of Both Extrinsic and Intrinsic Pathways in HCT 116 Human Colorectal Cancer Cells Contribute to Apoptosis through p53-Mediated ATM/Fas Signaling by Emilia sonchifolia Extract, a Folklore Medicinal Plant.

    Science.gov (United States)

    Lan, Yu-Hsuan; Chiang, Jo-Hua; Huang, Wen-Wen; Lu, Chi-Cheng; Chung, Jing-Gung; Wu, Tian-Shung; Jhan, Jia-Hua; Lin, Kuei-Li; Pai, Shu-Jen; Chiu, Yu-Jen; Tsuzuki, Minoru; Yang, Jai-Sing

    2012-01-01

    Emilia sonchifolia (L.) DC (Compositae), an herbaceous plant found in Taiwan and India, is used as folk medicine. The clinical applications include inflammation, rheumatism, cough, cuts fever, dysentery, analgesic, and antibacteria. The activities of Emilia sonchifolia extract (ESE) on colorectal cancer cell death have not been fully investigated. The purpose of this study explored the induction of apoptosis and its molecular mechanisms in ESE-treated HCT 116 human colorectal cancer cells in vitro. The methanolic ESE was characterized, and γ-humulene was formed as the major constituent (63.86%). ESE induced cell growth inhibition in a concentration- and time-dependent response by MTT assay. Apoptotic cells (DNA fragmentation, an apoptotic catachrestic) were found after ESE treatment by TUNEL assay and DNA gel electrophoresis. Alternatively, ESE stimulated the activities of caspase-3, -8, and -9 and their specific caspase inhibitors protected against ESE-induced cytotoxicity. ESE promoted the mitochondria-dependent and death-receptor-associated protein levels. Also, ESE increased ROS production and upregulated the levels of ATM, p53, and Fas in HCT 116 cells. Strikingly, p53 siRNA reversed ESE-reduced viability involved in p53-mediated ATM/Fas signaling in HCT 116 cells. In summary, our result is the first report suggesting that ESE may be potentially efficacious in the treatment of colorectal cancer.

  15. Combined low doses of PPARgamma and RXR ligands trigger an intrinsic apoptotic pathway in human breast cancer cells.

    Science.gov (United States)

    Bonofiglio, Daniela; Cione, Erika; Qi, Hongyan; Pingitore, Attilio; Perri, Mariarita; Catalano, Stefania; Vizza, Donatella; Panno, Maria Luisa; Genchi, Giuseppe; Fuqua, Suzanne A W; Andò, Sebastiano

    2009-09-01

    Ligand activation of peroxisome proliferator-activated receptor (PPAR)gamma and retinoid X receptor (RXR) induces antitumor effects in cancer. We evaluated the ability of combined treatment with nanomolar levels of the PPARgamma ligand rosiglitazone (BRL) and the RXR ligand 9-cis-retinoic acid (9RA) to promote antiproliferative effects in breast cancer cells. BRL and 9RA in combination strongly inhibit of cell viability in MCF-7, MCF-7TR1, SKBR-3, and T-47D breast cancer cells, whereas MCF-10 normal breast epithelial cells are unaffected. In MCF-7 cells, combined treatment with BRL and 9RA up-regulated mRNA and protein levels of both the tumor suppressor p53 and its effector p21(WAF1/Cip1). Functional experiments indicate that the nuclear factor-kappaB site in the p53 promoter is required for the transcriptional response to BRL plus 9RA. We observed that the intrinsic apoptotic pathway in MCF-7 cells displays an ordinated sequence of events, including disruption of mitochondrial membrane potential, release of cytochrome c, strong caspase 9 activation, and, finally, DNA fragmentation. An expression vector for p53 antisense abrogated the biological effect of both ligands, which implicates involvement of p53 in PPARgamma/RXR-dependent activity in all of the human breast malignant cell lines tested. Taken together, our results suggest that multidrug regimens including a combination of PPARgamma and RXR ligands may provide a therapeutic advantage in breast cancer treatment.

  16. MOFzyme: Intrinsic protease-like activity of Cu-MOF.

    Science.gov (United States)

    Li, Bin; Chen, Daomei; Wang, Jiaqiang; Yan, Zhiying; Jiang, Liang; Deliang Duan; He, Jiao; Luo, Zhongrui; Zhang, Jinping; Yuan, Fagui

    2014-10-24

    The construction of efficient enzyme mimetics for the hydrolysis of peptide bonds in proteins is challenging due to the high stability of peptide bonds and the importance of proteases in biology and industry. Metal-organic frameworks (MOFs) consisting of infinite crystalline lattices with metal clusters and organic linkers may provide opportunities for protease mimic which has remained unknown. Herein, we report that Cu₂(C₉H₃O₆)₄/₃ MOF (which is well known as HKUST-1 and denoted as Cu-MOF here), possesses an intrinsic enzyme mimicking activity similar to that found in natural trypsin to bovine serum albumin (BSA) and casein. The Michaelis constant (Km) of Cu-MOF is about 26,000-fold smaller than that of free trypsin indicating a much higher affinity of BSA for Cu-MOF surface. Cu-MOF also exhibited significantly higher catalytic efficiency than homogeneous artificial metalloprotease Cu(II) complexes and could be reused for ten times without losing in its activity. Moreover, Cu-MOF was successfully used to simulate trypsinization in cell culture since it dissociated cells in culture even without EDTA.

  17. Conformational equilibria and intrinsic affinities define integrin activation.

    Science.gov (United States)

    Li, Jing; Su, Yang; Xia, Wei; Qin, Yan; Humphries, Martin J; Vestweber, Dietmar; Cabañas, Carlos; Lu, Chafen; Springer, Timothy A

    2017-03-01

    We show that the three conformational states of integrin α5β1 have discrete free energies and define activation by measuring intrinsic affinities for ligand of each state and the equilibria linking them. The 5,000-fold higher affinity of the extended-open state than the bent-closed and extended-closed states demonstrates profound regulation of affinity. Free energy requirements for activation are defined with protein fragments and intact α5β1 On the surface of K562 cells, α5β1 is 99.8% bent-closed. Stabilization of the bent conformation by integrin transmembrane and cytoplasmic domains must be overcome by cellular energy input to stabilize extension. Following extension, headpiece opening is energetically favored. N-glycans and leg domains in each subunit that connect the ligand-binding head to the membrane repel or crowd one another and regulate conformational equilibria in favor of headpiece opening. The results suggest new principles for regulating signaling in the large class of receptors built from extracellular domains in tandem with single-span transmembrane domains.

  18. A Small Molecule that Induces Intrinsic Pathway Apoptosis with Unparalleled Speed

    Directory of Open Access Journals (Sweden)

    Rahul Palchaudhuri

    2015-12-01

    Full Text Available Apoptosis is generally believed to be a process that requires several hours, in contrast to non-programmed forms of cell death that can occur in minutes. Our findings challenge the time-consuming nature of apoptosis as we describe the discovery and characterization of a small molecule, named Raptinal, which initiates intrinsic pathway caspase-dependent apoptosis within minutes in multiple cell lines. Comparison to a mechanistically diverse panel of apoptotic stimuli reveals that Raptinal-induced apoptosis proceeds with unparalleled speed. The rapid phenotype enabled identification of the critical roles of mitochondrial voltage-dependent anion channel function, mitochondrial membrane potential/coupled respiration, and mitochondrial complex I, III, and IV function for apoptosis induction. Use of Raptinal in whole organisms demonstrates its utility for studying apoptosis in vivo for a variety of applications. Overall, rapid inducers of apoptosis are powerful tools that will be used in a variety of settings to generate further insight into the apoptotic machinery.

  19. Inositol Hexakisphosphate Mediates Apoptosis in Human Breast Adenocarcinoma MCF-7 Cell Line via Intrinsic Pathway

    Science.gov (United States)

    Agarwal, Rakhee; Ali, Nawab

    2010-04-01

    Inositol polyphosphates (InsPs) are naturally occurring compounds ubiquitously present in plants and animals. Inositol hexakisphosphate (InsP6) is the most abundant among all InsPs and constitutes the major portion of dietary fiber in most cereals, legumes and nuts. Certain derivatives of InsPs also regulate cellular signaling mechanisms. InsPs have also been shown to reduce tumor formation and induce apoptosis in cancerous cells. Therefore, in this study, the effects of InsPs on apoptosis were studied in an attempt to investigate their potential anti-cancer therapeutic application and understand their mechanism of action. Acridine orange and ethidium bromide staining suggested that InsP6 dose dependently induced apoptosis in human breast adenocarcinoma MCF-7 cells. Among InsPs tested (InsP3, InsP4, InsP5, and InsP6), InsP6 was found to be the most effective in inducing apoptosis. Furthermore, effects of InsP6 were found most potent inducing apoptosis. Etoposide, the drug known to induce apoptosis in both in vivo and in vitro, was used as a positive control. Western blotting experiments using specific antibodies against known apoptotic markers suggested that InsP6 induced apoptotic changes were mediated via an intrinsic apoptotic pathway.

  20. Cell-intrinsic in vivo requirement for the E47-p21 pathway in long-term hematopoietic stem cells.

    Science.gov (United States)

    Santos, Patricia M; Ding, Ying; Borghesi, Lisa

    2014-01-01

    Major regulators of long-term hematopoietic stem cell (LT-HSC) self-renewal and proliferation have been identified, but knowledge of their in vivo interaction in a linear pathway is lacking. In this study, we show a direct genetic link between the transcription factor E47 and the major cell cycle regulator p21 in controlling LT-HSC integrity in vivo under repopulation stress. Numerous studies have shown that E47 activates p21 transcription in hematopoietic subsets in vitro, and we now reveal the in vivo relevance of the E47-p21 pathway by reducing the gene dose of each factor individually (E47(het) or p21(het)) versus in tandem (E47(het)p21(het)). E47(het)p21(het) LT-HSCs and downstream short-term hematopoietic stem cells exhibit hyperproliferation and preferential susceptibility to mitotoxin compared to wild-type or single haploinsufficient controls. In serial adoptive transfers that rigorously challenge self-renewal, E47(het)p21(het) LT-HSCs dramatically and progressively decline, indicating the importance of cell-intrinsic E47-p21 in preserving LT-HSCs under stress. Transient numeric recovery of downstream short-term hematopoietic stem cells enabled the production of functionally competent myeloid but not lymphoid cells, as common lymphoid progenitors were decreased, and peripheral lymphocytes were virtually ablated. Thus, we demonstrate a developmental compartment-specific and lineage-specific requirement for the E47-p21 pathway in maintaining LT-HSCs, B cells, and T cells under hematopoietic repopulation stress in vivo.

  1. Dietary chlorophyllin inhibits the canonical NF-κB signaling pathway and induces intrinsic apoptosis in a hamster model of oral oncogenesis.

    Science.gov (United States)

    Thiyagarajan, P; Senthil Murugan, R; Kavitha, K; Anitha, P; Prathiba, D; Nagini, S

    2012-03-01

    Chlorophyllin, a water-soluble, semi-synthetic derivative of the ubiquitous green pigment chlorophyll is shown to exert potent anticarcinogenic effects. In the present study, we investigated the chemopreventive effects of chlorophyllin on 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis by analyzing the expression of NF-κB family members and markers of intrinsic apoptosis. Dietary administration of chlorophyllin (4 mg/kg bw) suppressed the development of HBP carcinomas by inhibiting the canonical NF-κB signaling pathway by downregulating IKKβ, preventing the phosphorylation of IκB-α, and reducing the expression of nuclear NF-κB. Inactivation of NF-κB signaling by chlorophyllin was associated with the induction of intrinsic apoptosis as evidenced by modulation of Bcl-2 family proteins, enforced nuclear localization of survivin, upregulation of apoptogenic molecules, activation of caspases, and cleavage of PARP. The results of the present study demonstrate that chlorophyllin inhibits the development of DMBA-induced HBP carcinogenesis by targeting NF-κB and the intrinsic apoptotic pathway. Thus, dietary agents such as chlorophyllin that simultaneously target divergent pathways of cell survival and cell death are novel candidates for cancer chemoprevention.

  2. Calcium-sensing receptor antagonist NPS2390 attenuates neuronal apoptosis though intrinsic pathway following traumatic brain injury in rats.

    Science.gov (United States)

    Xue, Zhaoliang; Song, Zhengfei; Wan, Yingfeng; Wang, Kun; Mo, Lianjie; Wang, Yirong

    2017-04-29

    Traumatic brain injury (TBI) initiates a complex cascade of neurochemical and signaling changes that leads to neuronal apoptosis, which contributes to poor outcomes for patients with TBI. Previous study indicates that calcium-sensing receptor (CaSR) activation contributes to neuron death in focal cerebral ischemia-reperfusion mice, however, its role in neuronal apoptosis after TBI is not well-established. Using a controlled cortical impact model in rats, the present study was designed to determine the effect of CaSR inhibitor NPS2390 upon neuronal apoptosis after TBI. Rats were randomly distributed into three groups undergoing the sham surgery or TBI procedure, and NPS2390 (1.5 mg/kg) was infused subcutaneously at 30 min and 120 min after TBI. All rats were sacrificed at 24 h after TBI. Our data indicated that NPS2390 significantly reduced the brain edema and improved the neurological function after TBI. In addition, NPS2390 decreased caspase-3 levels and the number of apoptotic neurons. Furthermore, NPS2390 up-regulated anti-apoptotic protein Bcl-2 expression and down-regulated pro-apoptotic protein Bax, and reduced subsequent release of cytochrome c into the cytosol. In summary, this study indicated that inhibition of CaSR by NPS2390 attenuates neuronal apoptosis after TBI, in part, through modulating intrinsic apoptotic pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Are there folding pathways in the functional stages of intrinsically disordered proteins?

    Science.gov (United States)

    Ilieva, N.; Liu, J.; Marinova, R.; Petkov, P.; Litov, L.; He, J.; Niemi, A. J.

    2016-10-01

    We proceed from the description of protein folding by means of molecular dynamics (MD) simulations with all-atom force fields, with folding pathways interpreted in terms of soliton structures, to identify possible systematic dynamical patterns of self-organisation that govern protein folding process. We perform in silico investigations of the conformational transformations of three different proteins - MYC protein (an α-helical protein), amylin and indolicidin (IDPs with different length and binding dynamics). We discuss the emergence of soliton-mediated secondary motifs, in the case of IDPs - in the context of their functional activity. We hypothesize that soliton-like quasi-ordered conformations appear as an important intermediate stage in this process.

  4. Do people differentiate between intrinsic and extrinsic goals for physical activity?

    Science.gov (United States)

    McLachlan, Sarah; Hagger, Martin S

    2011-04-01

    The distinction between intrinsic and extrinsic goals, and between goal pursuit for intrinsically and extrinsically motivated reasons, is a central premise of self-determination theory. Proponents of the theory have proposed that the pursuit of intrinsic goals and intrinsically motivated goal striving each predict adaptive psychological and behavioral outcomes relative to the pursuit of extrinsic goals and extrinsically motivated goal striving. Despite evidence to support these predictions, research has not explored whether individuals naturally differentiate between intrinsic and extrinsic goals. Two studies tested whether people make this differentiation when recalling goals for leisure-time physical activity. Using memory-recall methods, participants in Study 1 were asked to freely generate physical activity goals. A subsample (N = 43) was asked to code their freely generated goals as intrinsic or extrinsic. In Study 2, participants were asked to recall intrinsic and extrinsic goals after making a decision regarding their future physical activity. Results of these studies revealed that individuals' goal generation and recall exhibited significant clustering by goal type. Participants encountered some difficulties when explicitly coding goals. Findings support self-determination theory and indicate that individuals discriminate between intrinsic and extrinsic goals.

  5. Distinct and atypical intrinsic and extrinsic cell death pathways between photoreceptor cell types upon specific ablation of Ranbp2 in cone photoreceptors.

    Directory of Open Access Journals (Sweden)

    Kyoung-In Cho

    2013-06-01

    Full Text Available Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2, a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+ -apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct

  6. Dual Inhibition of PI3K/AKT and MEK/ERK Pathways Induces Synergistic Antitumor Effects in Diffuse Intrinsic Pontine Glioma Cells

    Directory of Open Access Journals (Sweden)

    Y. Linda Wu

    2017-04-01

    Full Text Available Diffuse intrinsic pontine glioma (DIPG is a devastating disease with an extremely poor prognosis. Recent studies have shown that platelet-derived growth factor receptor (PDGFR and its downstream effector pathway, PI3K/AKT/mTOR, are frequently amplified in DIPG, and potential therapies targeting this pathway have emerged. However, the addition of targeted single agents has not been found to improve clinical outcomes in DIPG, and targeting this pathway alone has produced insufficient clinical responses in multiple malignancies investigated, including lung, endometrial, and bladder cancers. Acquired resistance also seems inevitable. Activation of the Ras/Raf/MEK/ERK pathway, which shares many nodes of cross talk with the PI3K/AKT pathway, has been implicated in the development of resistance. In the present study, perifosine, a PI3K/AKT pathway inhibitor, and trametinib, a MEK inhibitor, were combined, and their therapeutic efficacy on DIPG cells was assessed. Growth delay assays were performed with each drug individually or in combination. Here, we show that dual inhibition of PI3K/AKT and MEK/ERK pathways synergistically reduced cell viability. We also reveal that trametinib induced AKT phosphorylation in DIPG cells that could not be effectively attenuated by the addition of perifosine, likely due to the activation of other compensatory mechanisms. The synergistic reduction in cell viability was through the pronounced induction of apoptosis, with some effect from cell cycle arrest. We conclude that the concurrent inhibition of the PI3K/AKT and MEK/ERK pathways may be a potential therapeutic strategy for DIPG.

  7. Activation of InsP3 receptors is sufficient for inducing graded intrinsic plasticity in rat hippocampal pyramidal neurons

    Science.gov (United States)

    Ashhad, Sufyan; Johnston, Daniel

    2014-01-01

    The synaptic plasticity literature has focused on establishing necessity and sufficiency as two essential and distinct features in causally relating a signaling molecule to plasticity induction, an approach that has been surprisingly lacking in the intrinsic plasticity literature. In this study, we complemented the recently established necessity of inositol trisphosphate (InsP3) receptors (InsP3R) in a form of intrinsic plasticity by asking if InsP3R activation was sufficient to induce intrinsic plasticity in hippocampal neurons. Specifically, incorporation of d-myo-InsP3 in the recording pipette reduced input resistance, maximal impedance amplitude, and temporal summation but increased resonance frequency, resonance strength, sag ratio, and impedance phase lead. Strikingly, the magnitude of plasticity in all these measurements was dependent on InsP3 concentration, emphasizing the graded dependence of such plasticity on InsP3R activation. Mechanistically, we found that this InsP3-induced plasticity depended on hyperpolarization-activated cyclic nucleotide-gated channels. Moreover, this calcium-dependent form of plasticity was critically reliant on the release of calcium through InsP3Rs, the influx of calcium through N-methyl-d-aspartate receptors and voltage-gated calcium channels, and on the protein kinase A pathway. Our results delineate a causal role for InsP3Rs in graded adaptation of neuronal response dynamics, revealing novel regulatory roles for the endoplasmic reticulum in neural coding and homeostasis. PMID:25552640

  8. Putamen Activation Represents an Intrinsic Positive Prediction Error Signal for Visual Search in Repeated Configurations.

    Science.gov (United States)

    Sommer, Susanne; Pollmann, Stefan

    2016-01-01

    We investigated fMRI responses to visual search targets appearing at locations that were predicted by the search context. Based on previous work in visual category learning we expected an intrinsic reward prediction error signal in the putamen whenever the target appeared at a location that was predicted with some degree of uncertainty. Comparing target appearance at locations predicted with 50% probability to either locations predicted with 100% probability or unpredicted locations, increased activation was observed in left posterior putamen and adjacent left posterior insula. Thus, our hypothesis of an intrinsic prediction error-like signal was confirmed. This extends the observation of intrinsic prediction error-like signals, driven by intrinsic rather than extrinsic reward, to memory-driven visual search.

  9. Putamen Activation Represents an Intrinsic Positive Prediction Error Signal for Visual Search in Repeated Configurations

    Science.gov (United States)

    Sommer, Susanne; Pollmann, Stefan

    2016-01-01

    We investigated fMRI responses to visual search targets appearing at locations that were predicted by the search context. Based on previous work in visual category learning we expected an intrinsic reward prediction error signal in the putamen whenever the target appeared at a location that was predicted with some degree of uncertainty. Comparing target appearance at locations predicted with 50% probability to either locations predicted with 100% probability or unpredicted locations, increased activation was observed in left posterior putamen and adjacent left posterior insula. Thus, our hypothesis of an intrinsic prediction error-like signal was confirmed. This extends the observation of intrinsic prediction error-like signals, driven by intrinsic rather than extrinsic reward, to memory-driven visual search. PMID:27867436

  10. PLGA-PLL-PEG-Tf-based targeted nanoparticles drug delivery system enhance antitumor efficacy via intrinsic apoptosis pathway

    Directory of Open Access Journals (Sweden)

    Bao W

    2015-01-01

    the DNR-loaded NPs group than that in other ones. Interestingly, pathological assessment showed no apparent damage to the main organs. In summary, the results obtained from this study showed that the novel NPs DDS could improve the efficacy of DNR in the treatment of leukemia and induce apoptosis via intrinsic pathway. Thus, it can be inferred that the new drug delivery may be a useful clinical tool.Keywords: PLGA-PLL-PEG, daunorubicin, transferrin, K562 cells, apoptosis

  11. PLGA-PLL-PEG-Tf-based targeted nanoparticles drug delivery system enhance antitumor efficacy via intrinsic apoptosis pathway.

    Science.gov (United States)

    Bao, Wen; Liu, Ran; Wang, Yonglu; Wang, Fei; Xia, Guohua; Zhang, Haijun; Li, Xueming; Yin, Haixiang; Chen, Baoan

    2015-01-01

    Chemotherapy offers a systemic cancer treatment; however, it is limited in clinical administration due to its serious side effects. In cancer medicine, the use of nanoparticles (NPs) drug delivery system (DDS) can sustainedly release anticancer drug at the specific site and reduce the incidence of toxicity in normal tissues. In the present study, we aimed to evaluate the benefit of a novel chemotherapeutic DDS and its underlying mechanisms. Daunorubicin (DNR) was loaded into poly (lactic-co-glycolic acid) (PLGA)-poly-L-lysine (PLL)-polyethylene glycol (PEG)-transferrin (Tf) NPs to construct DNR-PLGA-PLL-PEG-Tf-NPs (DNR-loaded NPs) as a DDS. After incubating with PLGA-PLL-PEG-Tf-NPs, DNR, and DNR-loaded NPs, the leukemia K562 cells were collected and the intracellular concentration of DNR was detected by flow cytometry, respectively. Furthermore, the effect of drugs on the growth of tumors in K562 xenografts was observed and the relevant toxicity of therapeutic drugs on organs was investigated in vivo. Meanwhile, cell apoptosis in the excised xenografts was measured by transferase-mediated dUTP nick-end labeling assay, and the expression of apoptosis-related proteins, including Bcl-2, Bax, Caspase-9, Caspase-3, and cleaved-PARP, was determined by Western blotting analysis. Results showed that DNR-loaded NPs increased intracellular concentration of DNR in K562 cells in vitro and induced a remarkable improvement in anticancer activity in the xenografts in vivo. The expression of Bcl-2 protein was downregulated and that of Bax, Caspase-9, Caspase-3, and cleaved-PARP proteins were obviously upregulated in the DNR-loaded NPs group than that in other ones. Interestingly, pathological assessment showed no apparent damage to the main organs. In summary, the results obtained from this study showed that the novel NPs DDS could improve the efficacy of DNR in the treatment of leukemia and induce apoptosis via intrinsic pathway. Thus, it can be inferred that the new drug

  12. Classroom Activity and Intrinsic Motivationin EFL Teaching and Learning

    Institute of Scientific and Technical Information of China (English)

    郑玉全

    2015-01-01

    The question of how to motivate language learners has been a neglected area in L2 motivation research, and even thefew available analyses lack an adequate research base. This article presents the results of an empirical survey aimed at initiatinginterviews and conducting follow-up questionnaire to obtain classroom data on motivational classroom teaching activities and theactual effect of these strategies. This current study provides new insights into English classroom teaching with further researchinvestigation and teaching implication to promote students' integrative motivation through classroom teaching activities.

  13. Genioglossus and intrinsic electromyographic activities in impeded and unimpeded protrusion tasks.

    Science.gov (United States)

    Pittman, Lora J; Bailey, E Fiona

    2009-01-01

    Eight muscles invest the human tongue: four extrinsic muscles have external origins and insert into the tongue body and four intrinsic muscles originate and terminate within the tongue. Previously, we noted minimal activation of the genioglossus tongue muscle during impeded protrusion tasks (i.e., having subjects push the tongue against a force transducer), suggesting that other muscles play a role in the production of tongue force. Accordingly, we sought to characterize genioglossus tongue muscle activities during impeded and unimpeded protrusion tasks (i.e., having subjects slowly and smoothly move the tongue out of their mouth). Electromyographic (EMG) and single motor-unit potentials of the extrinsic genioglossus muscle were recorded with tungsten microelectrodes and EMG activities of intrinsic tongue muscles were recorded with hook-wire electrodes inserted into the anterior tongue body. Tongue position was detected by an isotonic transducer coupled to the tongue tip. Protrusive force was detected by a force transducer attached to a rigid bar. Genioglossus and intrinsic tongue muscles were simultaneously active in both impeded and unimpeded protrusion tasks. Genioglossus whole muscle EMG and single motor-unit activities changed faithfully as a function of tongue position, with increased discharge associated with protrusion and decreased discharge associated with retraction back to the rest position. In contrast, during the impeded protrusion task drive the genioglossus muscle remained constant as protrusion force increased. Conversely, intrinsic tongue muscle activities appropriately followed changes in both tongue position and force. Importantly, we observed significantly higher levels of intrinsic muscle activity in the impeded protrusion task. These observations suggest that protrusion of the human tongue requires activation of the genioglossus and intrinsic protrudor muscles, with the former more important for establishing anterior-posterior tongue location

  14. N-methyl-D-aspartate receptor encephalitis mediates loss of intrinsic activity measured by functional MRI.

    Science.gov (United States)

    Brier, Matthew R; Day, Gregory S; Snyder, Abraham Z; Tanenbaum, Aaron B; Ances, Beau M

    2016-06-01

    Spontaneous brain activity is required for the development and maintenance of normal brain function. Many disease processes disrupt the organization of intrinsic brain activity, but few pervasively reduce the amplitude of resting state blood oxygen level dependent (BOLD) fMRI fluctuations. We report the case of a female with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, longitudinally studied during the course of her illness to determine the contribution of NMDAR signaling to spontaneous brain activity. Resting state BOLD fMRI was measured at the height of her illness and 18 weeks following discharge from hospital. Conventional resting state networks were defined using established methods. Correlation and covariance matrices were calculated by extracting the BOLD time series from regions of interest and calculating either the correlation or covariance quantity. The intrinsic activity was compared between visits, and to expected activity from 45 similarly aged healthy individuals. Near the height of the illness, the patient exhibited profound loss of consciousness, high-amplitude slowing of the electroencephalogram, and a severe reduction in the amplitude of spontaneous BOLD fMRI fluctuations. The patient's neurological status and measures of intrinsic activity improved following treatment. We conclude that NMDAR-mediated signaling plays a critical role in the mechanisms that give rise to organized spontaneous brain activity. Loss of intrinsic activity is associated with profound disruptions of consciousness and cognition.

  15. Relations of perception of responsibility to intrinsic motivation and physical activity among Korean middle school students.

    Science.gov (United States)

    Lee, Okseon; Kim, Younhee; Kim, Oung Jun

    2012-12-01

    To validate the Personal and Social Responsibility Questionnaire, the relations between perceived responsibility and intrinsic motivation were examined among Korean middle school students. The relations of change in stages of physical activity and students' perceived responsibility were also examined. Participants were 357 middle school students (160 boys, 197 girls) from three schools in the Seoul metropolitan area. Exploratory factor analysis supported a three-factor structure with effort and self-direction merged into one factor and the responsibilities of respect and caring for others constituted separate factors. Pearson correlations among factors showed perceptions of personal responsibility were associated with more intrinsic motivation toward physical education and a higher stage of physical activity. A moderate or low association between perceived social responsibility and intrinsic motivation implied a need to develop strategies for Korean students to use social responsibility for promoting physical activity.

  16. Effect of Autaptic Activity on Intrinsic Coherence Resonance in Newman-Watts Networks of Stochastic Hodgkin-Huxley Neurons

    Science.gov (United States)

    Wang, Qi; Gong, Yubing

    2016-06-01

    In this paper, we study the effect of autaptic activity on intrinsic coherence resonance (CR) induced by channel noise in Newman-Watts (NW) networks of stochastic Hodgkin-Huxley (HH) neurons. It is found that autaptic strength and autaptic delay have a big effect on the intrinsic CR. As autaptic strength increases, there is optimal autaptic strength by which the intrinsic CR is most highly enhanced. Autaptic delay can enhance, reduce, or destroy the intrinsic CR, depending on the delay length. Moreover, there are optimal coupling strength and network randomness by which autaptic activity can most highly enhance the intrinsic CR. These results show that autaptic activity has different effects on the intrinsic CR in the neuronal networks, and it can most highly enhance the intrinsic CR at optimal coupling strength and network randomness. These findings could find potential implications of channel noise and autaptic activity for the information processing and transmission in neural systems.

  17. High-affinity benzodiazepine receptor ligands among benzodiazepines and betacarbolines with different intrinsic activity

    Energy Technology Data Exchange (ETDEWEB)

    Yliniemelae, A.; Gynther, J. (Univ. of Kuopio (Finland)); Konschin, H.; Tylli, H. (Univ. of Helsinki (Finland)); Rouvinen, J. (Univ. of Joensuu (Finland))

    1989-01-01

    Structural and electrostatic features of diazepam, flumazenil, and methyl betacarboline-3-carboxylate (BCCM) have been investigated using the molecular superimposition method. These high-affinity benzodiazepine (BZ) receptor ligands are structurally unrelated and they have different intrinsic activity. These ligands are superimposed in such a way that common structural and electrostatic features essential for the high receptor binding affinity overlap. In addition to this binding pharmacophore, there are roughly three separate binding zones in the BZ receptor, one for each class of ligands. The intrinsic activity of BZ receptor ligands depends on the molecular structures and the way the ligand approaches the receptor.

  18. Mechanisms of drug sensitization to TRA-8, an agonistic death receptor 5 antibody, involve modulation of the intrinsic apoptotic pathway in human breast cancer cells.

    Science.gov (United States)

    Amm, Hope M; Zhou, Tong; Steg, Adam D; Kuo, Huichien; Li, Yufeng; Buchsbaum, Donald J

    2011-04-01

    TRA-8, a monoclonal antibody to death receptor 5 induces apoptosis in various cancer cells; however, the degree of sensitivity varies from highly sensitive to resistant. We have previously shown that resistance to TRA-8 can be reversed by using chemotherapeutic agents, but the mechanism underlying this sensitization was not fully understood. Here, we examined the combination of TRA-8 with doxorubicin or bortezomib in breast cancer cells. In TRA-8-resistant BT-474 and T47D cells, both chemotherapy agents synergistically sensitized cells to TRA-8 cytotoxicity with enhanced activation of apoptosis shown by cleavage of caspases and PARP, reduced Bid, increased proapoptotic Bcl-2 proteins, and increased mitochondrial membrane depolarization. Doxorubicin or bortezomib combined with TRA-8 also reduced Bcl-XL and X-linked inhibitors of apoptosis (XIAP) in treated cells. Furthermore, targeting these proteins with pharmacologic modulators, AT-101, BH3I-2' and AT-406, produced sensitization to TRA-8. TRA-8 combined with AT-101 or BH3I-2', inhibitors of antiapoptotic Bcl-2 proteins, produced synergistic cytotoxicity against ZR-75-1, BT-474, and T47D cells. The IAP-targeting compound, AT-406, was synergistic with TRA-8 in BT-474 cells, and to a lesser extent T47D cells. Activation of the intrinsic apoptotic pathway was a common mechanism associated with sensitization of TRA-8-resistant breast cancer cell lines. Collectively, these studies show that the Bcl-2 and IAP families of proteins are involved in TRA-8 and chemotherapy resistance via their modulation of the intrinsic apoptotic pathway. Targeting these proteins with novel agents sensitized TRA-8-resistant breast cancer cells, suggesting this approach may represent a potent therapeutic strategy in the treatment of breast cancer. ©2011 AACR.

  19. Spermatocyte apoptosis, which involves both intrinsic and extrinsic pathways, explains the sterility of Graomys griseoflavus x Graomys centralis male hybrids.

    Science.gov (United States)

    Rodriguez, Valeria; Diaz de Barboza, Gabriela; Ponce, Ruben; Merico, Valeria; Garagna, Silvia; Tolosa de Talamoni, Nori

    2010-01-01

    Spermatogenic impairment and the apoptotic pathways involved in establishing sterility of male hybrids obtained from crossing Graomys griseoflavus females with Graomys centralis males were studied. Testes from G. centralis, G. griseoflavus and hybrids were compared at different ages. Terminal transferase-mediated dUTP nick-end labelling assay (TUNEL), Fas, Bax and cytochrome c labelling were used for apoptosis evaluation, and calbindin D(28k) staining as an anti-apoptotic molecule. In 1-month-old animals, spermatocytes were positive for all apoptotic markers, but moderate TUNEL (+) spermatocyte frequency was only found in G. centralis. At subsequent ages, the apoptotic markers were downregulated in testes from parental cytotypes, but not in hybrid testes. TUNEL (+) spermatocytes were present at 78% and 44% per tubule cross-section in 2- and 3-month-old hybrid animals, respectively. Pachytene spermatocyte death in adult hybrids occurs via apoptosis, as revealed by high caspase-3 expression. Calbindin was highly expressed in spermatocytes of adult hybrids, in which massive cell death occurs via apoptosis. Calbindin co-localisation with TUNEL or Fas, Bax and cytochrome c was very limited, suggesting an inverse regulation of calbindin and apoptotic markers. Hybrid sterility is due to breakdown of spermatogenesis at the pachytene spermatocyte stage. Both extrinsic and intrinsic pathways are involved in apoptosis of spermatocytes, which are the most sensitive cell type to apoptotic stimuli.

  20. An intrinsic gut leptin-melanocortin pathway modulates intestinal microsomal triglyceride transfer protein and lipid absorption.

    Science.gov (United States)

    Iqbal, Jahangir; Li, Xiaosong; Chang, Benny Hung-Junn; Chan, Lawrence; Schwartz, Gary J; Chua, Streamson C; Hussain, M Mahmood

    2010-07-01

    Fat is delivered to tissues by apoB-containing lipoproteins synthesized in the liver and intestine with the help of an intracellular chaperone, microsomal triglyceride transfer protein (MTP). Leptin, a hormone secreted by adipose tissue, acts in the brain and on peripheral tissues to regulate fat storage and metabolism. Our aim was to identify the role of leptin signaling in MTP regulation and lipid absorption using several mouse models deficient in leptin receptor (LEPR) signaling and downstream effectors. Mice with spontaneous LEPR B mutations or targeted ablation of LEPR B in proopiomelanocortin (POMC) or agouti gene related peptide (AGRP) expressing cells had increased triglyceride in plasma, liver, and intestine. Furthermore, melanocortin 4 receptor (MC4R) knockout mice expressed a similar triglyceride phenotype, suggesting that leptin might regulate intestinal MTP expression through the melanocortin pathway. Mechanistic studies revealed that the accumulation of triglyceride in the intestine might be secondary to decreased expression of MTP and lipid absorption in these mice. Surgical and chemical blockade of vagal efferent outflow to the intestine in wild-type mice failed to alter the triglyceride phenotype, demonstrating that central neural control mechanisms were likely not involved in the observed regulation of intestinal MTP. Instead, we found that enterocytes express LEPR, POMC, AGRP, and MC4R. We propose that a peripheral, local gut signaling mechanism involving LEPR B and MC4R regulates intestinal MTP and controls intestinal lipid absorption.

  1. (Glyco)-protein drug carriers with an intrinsic therapeutic activity : The concept of dual targeting

    NARCIS (Netherlands)

    Meijer, DKF; Molema, G; Moolenaar, F; deZeeuw, D; Swart, PJ

    1996-01-01

    Dual targeting can in principle be achieved by using intrinsically active carriers that not only deliver the conjugated drug but also otherwise influence the pathological process. Potential carriers of this kind are monoclonal antibodies, certain interferons and interleukins, as well as certain enzy

  2. Constitutively active signaling by the G protein βγ-subunit mediates intrinsically increased phosphodiesterase-4 activity in human asthmatic airway smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Aihua Hu

    Full Text Available Signaling by the Gβγ subunit of Gi protein, leading to downstream c-Src-induced activation of the Ras/c-Raf1/MEK-ERK1/2 signaling pathway and its upregulation of phosphodiesterase-4 (PDE4 activity, was recently shown to mediate the heightened contractility in proasthmatic sensitized isolated airway smooth muscle (ASM, as well as allergen-induced airway hyperresponsiveness and inflammation in an in vivo animal model of allergic asthma. This study investigated whether cultured human ASM (HASM cells derived from asthmatic donor lungs exhibit constitutively increased PDE activity that is attributed to intrinsically upregulated Gβγ signaling coupled to c-Src activation of the Ras/MEK/ERK1/2 cascade. We show that, relative to normal cells, asthmatic HASM cells constitutively exhibit markedly increased intrinsic PDE4 activity coupled to heightened Gβγ-regulated phosphorylation of c-Src and ERK1/2, and direct co-localization of the latter with the PDE4D isoform. These signaling events and their induction of heightened PDE activity are acutely suppressed by treating asthmatic HASM cells with a Gβγ inhibitor. Importantly, along with increased Gβγ activation, asthmatic HASM cells also exhibit constitutively increased direct binding of the small Rap1 GTPase-activating protein, Rap1GAP, to the α-subunit of Gi protein, which serves to cooperatively facilitate Ras activation and, thereby, enable enhanced Gβγ-regulated ERK1/2-stimulated PDE activity. Collectively, these data are the first to identify that intrinsically increased signaling via the Gβγ subunit, facilitated by Rap1GAP recruitment to the α-subunit, mediates the constitutively increased PDE4 activity detected in asthmatic HASM cells. These new findings support the notion that interventions targeted at suppressing Gβγ signaling may lead to novel approaches to treat asthma.

  3. Sanguinarine induces apoptosis of human osteosarcoma cells through the extrinsic and intrinsic pathways

    Energy Technology Data Exchange (ETDEWEB)

    Park, Hyunjin; Bergeron, Eric; Senta, Helena; Guillemette, Kim [Cell-Biomaterial Biohybrid Systems, Universite de Sherbrooke, Department of Chemical Engineering and Biotechnological Engineering, Canada J1K 2R1 (Canada); Beauvais, Sabrina [Cell-Biomaterial Biohybrid Systems, Universite de Sherbrooke, Department of Chemical Engineering and Biotechnological Engineering, Canada J1K 2R1 (Canada); Development of Bioprocess, Universite de Sherbrooke, Department of Chemical Engineering and Biotechnological Engineering, Canada J1K 2R1 (Canada); Blouin, Richard [Universite de Sherbrooke, Department of Biology, Canada J1K 2R1 (Canada); Sirois, Joel [Development of Bioprocess, Universite de Sherbrooke, Department of Chemical Engineering and Biotechnological Engineering, Canada J1K 2R1 (Canada); Faucheux, Nathalie, E-mail: Nathalie.Faucheux@Usherbrooke.ca [Cell-Biomaterial Biohybrid Systems, Universite de Sherbrooke, Department of Chemical Engineering and Biotechnological Engineering, Canada J1K 2R1 (Canada)

    2010-08-27

    Research highlights: {yields} We show for the first time the effect of sanguinarine (SA) on MG63 and SaOS-2 cells. {yields} SA altered osteosarcoma cell viability in a concentration and time dependent manner. {yields} SA induced osteosarcoma cell apoptosis and increased caspase-8 and -9 activities. {yields} SA decreased dose dependently the Bcl-2 protein level only in MG63 cells. {yields} SaOS-2 which are osteoblast-derived, seemed more resistant to SA than MG63. -- Abstract: The quaternary benzo[c]phenanthridine alkaloid sanguinarine inhibits the proliferation of cancerous cells from different origins, including lung, breast, pancreatic and colon, but nothing is known of its effects on osteosarcoma, a primary malignant bone tumour. We have found that sanguinarine alters the morphology and reduces the viability of MG-63 and SaOS-2 human osteosarcoma cell lines in concentration- and time-dependent manner. Incubation with 1 {mu}mol/L sanguinarine for 4 and 24 h killed more efficiently MG-63 cells than SaOS-2 cells, while incubation with 5 {mu}mol/L sanguinarine killed almost 100% of both cell populations within 24 h. This treatment also changed the mitochondrial membrane potential in both MG-63 and SaOS-2 cells within 1 h, caused chromatin condensation and the formation of apoptotic bodies. It activated multicaspases, and increased the activities of caspase-8 and caspase-9 in both MG-63 and SaOS-2 cells. These data highlight sanguinarine as a novel potential agent for bone cancer therapy.

  4. Opposing Effects of Intrinsic Conductance and Correlated Synaptic Input on V-Fluctuations during Network Activity

    DEFF Research Database (Denmark)

    Kolind, Jens; Hounsgaard, Jørn Dybkjær; Berg, Rune W

    2012-01-01

    Neurons often receive massive concurrent bombardment of synaptic inhibition and excitation during functional network activity. This increases membrane conductance and causes fluctuations in membrane potential (V(m)) and spike timing. The conductance increase is commonly attributed to synaptic...... conductance, but also includes the intrinsic conductances recruited during network activity. These two sources of conductance have contrasting dynamic properties at sub-threshold membrane potentials. Synaptic transmitter gated conductance changes abruptly and briefly with each presynaptic action potential....... If the spikes arrive at random times the changes in synaptic conductance are therefore stochastic and rapid during intense network activity. In comparison, sub-threshold intrinsic conductances vary smoothly in time. In the present study this discrepancy is investigated using two conductance-based models: a (1...

  5. Increased Intrinsic Brain Activity in the Striatum Reflects Symptom Dimensions in Schizophrenia

    Science.gov (United States)

    Sorg, Christian; Manoliu, Andrei; Neufang, Susanne; Myers, Nicholas; Peters, Henning; Schwerthöffer, Dirk; Scherr, Martin; Mühlau, Mark; Zimmer, Claus; Drzezga, Alexander; Förstl, Hans; Bäuml, Josef; Eichele, Tom; Wohlschläger, Afra M.; Riedl, Valentin

    2013-01-01

    Striatal dysfunction is thought to be a fundamental element in schizophrenia. Striatal dopamine dysfunction impacts on reward processing and learning and is present even at rest. Here, we addressed the question whether and how spontaneous neuronal activity in the striatum is altered in schizophrenia. We therefore assessed intrinsic striatal activity and its relation with disorder states and symptom dimensions in patients with schizophrenia. We performed resting-state functional (rs-fMRI) and structural magnetic resonance imaging as well as psychometric assessment in 21 schizophrenic patients during psychosis. On average 9 months later, we acquired follow-up data during psychotic remission and with comparable levels of antipsychotic medication. Twenty-one age- and sex-matched healthy controls were included in the study. Independent component analysis of fMRI data yielded spatial maps and time-courses of coherent ongoing blood-oxygen-level-dependent signal fluctuations, which were used for group comparisons and correlation analyses with scores of the positive and negative syndrome scale. During psychosis, coherent intrinsic activity of the striatum was increased in the dorsal part and correlated with positive symptoms such as delusion and hallucination. In psychotic remission of the same patients, activity of the ventral striatum was increased and correlated with negative symptoms such as emotional withdrawal and blunted affect. Results were controlled for volumetric and medication effects. These data provide first evidence that in schizophrenia intrinsic activity is changed in the striatum and corresponds to disorder states and symptom dimensions. PMID:22241165

  6. Changes in At-Risk Boys' Intrinsic Motivation toward Physical Activity: A Three-Year Longitudinal Study

    Science.gov (United States)

    Liu, Jiling; Xiang, Ping; McBride, Ron E.; Su, Xiaoxia; Juzaily, Nasnoor

    2015-01-01

    Intrinsic motivation (IM) is an important predictor of children's physical activity participation. The present 3-year longitudinal study examined changes in IM toward physical activity among a group of at-risk boys (N = 92) at a summer sports camp. Results showed the boys were intrinsically motivated in their first camp year, but their IM levels…

  7. Changes in At-Risk Boys' Intrinsic Motivation toward Physical Activity: A Three-Year Longitudinal Study

    Science.gov (United States)

    Liu, Jiling; Xiang, Ping; McBride, Ron E.; Su, Xiaoxia; Juzaily, Nasnoor

    2015-01-01

    Intrinsic motivation (IM) is an important predictor of children's physical activity participation. The present 3-year longitudinal study examined changes in IM toward physical activity among a group of at-risk boys (N = 92) at a summer sports camp. Results showed the boys were intrinsically motivated in their first camp year, but their IM levels…

  8. Reduced Hyperpolarization-Activated Current Contributes to Enhanced Intrinsic Excitability in Cultured Hippocampal Neurons from PrP(-/-) Mice.

    Science.gov (United States)

    Fan, Jing; Stemkowski, Patrick L; Gandini, Maria A; Black, Stefanie A; Zhang, Zizhen; Souza, Ivana A; Chen, Lina; Zamponi, Gerald W

    2016-01-01

    Genetic ablation of cellular prion protein (PrP(C)) has been linked to increased neuronal excitability and synaptic activity in the hippocampus. We have previously shown that synaptic activity in hippocampi of PrP-null mice is increased due to enhanced N-methyl-D-aspartate receptor (NMDAR) function. Here, we focused on the effect of PRNP gene knock-out (KO) on intrinsic neuronal excitability, and in particular, the underlying ionic mechanism in hippocampal neurons cultured from P0 mouse pups. We found that the absence of PrP(C) profoundly affected the firing properties of cultured hippocampal neurons in the presence of synaptic blockers. The membrane impedance was greater in PrP-null neurons, and this difference was abolished by the hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker ZD7288 (100 μM). HCN channel activity appeared to be functionally regulated by PrP(C). The amplitude of voltage sag, a characteristic of activating HCN channel current (I h), was decreased in null mice. Moreover, I h peak current was reduced, along with a hyperpolarizing shift in activation gating and slower kinetics. However, neither HCN1 nor HCN2 formed a biochemical complex with PrP(C). These results suggest that the absence of PrP downregulates the activity of HCN channels through activation of a cell signaling pathway rather than through direct interactions. This in turn contributes to an increase in membrane impedance to potentiate neuronal excitability.

  9. Hemagglutinin protease secreted by V. cholerae induced apoptosis in breast cancer cells by ROS mediated intrinsic pathway and regresses tumor growth in mice model.

    Science.gov (United States)

    Ray, Tanusree; Chakrabarti, Monoj Kumar; Pal, Amit

    2016-02-01

    Conventional anticancer therapies are effective but have side effects, so alternative targets are being developed. Bacterial toxins that can kill cells or alter the cellular processes like proliferation, apoptosis and differentiation have been reported for cancer treatment. In this study we have shown antitumor activity of hemagglutinin protease (HAP) secreted by Vibrio cholerae. One µg of HAP showed potent antitumor activity when injected into Ehrlich ascites carcinoma (EAC) tumors in Swiss albino mice. Weekly administration of this dose is able to significantly diminish a large tumor volume within 3 weeks and increases the survival rates of cancerous mice. HAP showed apoptotic activity on EAC and other malignant cells. Increased level of pro-apoptotic p53 with increased ratio of pro-apoptotic Bax to anti-apoptotic Bcl-2 signify that HAP induced apoptogenic signals lead to death of the tumor cells. In vivo and ex vivo studies suggest that mitochondrial dependent intrinsic pathway is responsible for this apoptosis. The level of ROS in malignant cells is reported to be higher than the normal healthy cells. HAP induces oxidative stress and increases the level of ROS in malignant cells which is significantly higher than the normal healthy cells. As a result the malignant cells cross the threshold level of ROS for cell survival faster than normal healthy cells. This mechanism causes HAP mediated apoptosis in malignant cells, but normal cells remain unaltered in the same environment. Our study suggests that HAP may be used as a new candidate drug for cancer therapy.

  10. Lung carcinoma signaling pathways activated by smoking

    Institute of Scientific and Technical Information of China (English)

    Jing Wen; Jian-Hua Fu; Wei Zhang; Ming Guo

    2011-01-01

    Lung cancer is the leading cause of cancer death in men and women worldwide, with over a million deaths annually. Tobacco smoke is the major etiologic risk factor for lung cancer in current or previous smokers and has been strongly related to certain types of lung cancer, such as small cell lung carcinoma and squamous cell lung carcinoma. In recent years, there has been an increased incidence of lung adenocarcinoma. This change is strongly associated with changes in smoking behavior and cigarette design. Carcinogens present in tobacco products and their intermediate metabolites can activate multiple signaling pathways that contribute to lung cancer carcinogenesis. In this review, we summarize the smoking-activated signaling pathways involved in lung cancer.

  11. Circular polarization intrinsic optical signal recording of stimulus-evoked neural activity.

    Science.gov (United States)

    Lu, Rong-Wen; Zhang, Qiu-Xiang; Yao, Xin-Cheng

    2011-05-15

    Linear polarization intrinsic optical signal (LP-IOS) measurement can provide sensitive detection of neural activities in stimulus-activated neural tissues. However, the LP-IOS magnitude and signal-to-noise ratio (SNR) are highly correlated with the nerve orientation relative to the polarization plane of the incident light. Because of the complexity of orientation dependency, LP-IOS optimization and outcome interpretation are time consuming and complicated. In this study, we demonstrate the feasibility of circular polarization intrinsic optical signal (CP-IOS) measurement. Our theoretical modeling and experimental investigation indicate that CP-IOS magnitude and SNR are independent from the nerve orientation. Therefore, CP-IOS promises a practical method for polarization IOS imaging of complex neural systems.

  12. Evidence from intrinsic activity that asymmetry of the human brain is controlled by multiple factors.

    Science.gov (United States)

    Liu, Hesheng; Stufflebeam, Steven M; Sepulcre, Jorge; Hedden, Trey; Buckner, Randy L

    2009-12-01

    Cerebral lateralization is a fundamental property of the human brain and a marker of successful development. Here we provide evidence that multiple mechanisms control asymmetry for distinct brain systems. Using intrinsic activity to measure asymmetry in 300 adults, we mapped the most strongly lateralized brain regions. Both men and women showed strong asymmetries with a significant, but small, group difference. Factor analysis on the asymmetric regions revealed 4 separate factors that each accounted for significant variation across subjects. The factors were associated with brain systems involved in vision, internal thought (the default network), attention, and language. An independent sample of right- and left-handed individuals showed that hand dominance affects brain asymmetry but differentially across the 4 factors supporting their independence. These findings show the feasibility of measuring brain asymmetry using intrinsic activity fluctuations and suggest that multiple genetic or environmental mechanisms control cerebral lateralization.

  13. Intrinsic activity in the fly brain gates visual information during behavioral choices.

    Directory of Open Access Journals (Sweden)

    Shiming Tang

    Full Text Available The small insect brain is often described as an input/output system that executes reflex-like behaviors. It can also initiate neural activity and behaviors intrinsically, seen as spontaneous behaviors, different arousal states and sleep. However, less is known about how intrinsic activity in neural circuits affects sensory information processing in the insect brain and variability in behavior. Here, by simultaneously monitoring Drosophila's behavioral choices and brain activity in a flight simulator system, we identify intrinsic activity that is associated with the act of selecting between visual stimuli. We recorded neural output (multiunit action potentials and local field potentials in the left and right optic lobes of a tethered flying Drosophila, while its attempts to follow visual motion (yaw torque were measured by a torque meter. We show that when facing competing motion stimuli on its left and right, Drosophila typically generate large torque responses that flip from side to side. The delayed onset (0.1-1 s and spontaneous switch-like dynamics of these responses, and the fact that the flies sometimes oppose the stimuli by flying straight, make this behavior different from the classic steering reflexes. Drosophila, thus, seem to choose one stimulus at a time and attempt to rotate toward its direction. With this behavior, the neural output of the optic lobes alternates; being augmented on the side chosen for body rotation and suppressed on the opposite side, even though the visual input to the fly eyes stays the same. Thus, the flow of information from the fly eyes is gated intrinsically. Such modulation can be noise-induced or intentional; with one possibility being that the fly brain highlights chosen information while ignoring the irrelevant, similar to what we know to occur in higher animals.

  14. Genioglossus and Intrinsic Electromyographic Activities in Impeded and Unimpeded Protrusion Tasks

    OpenAIRE

    2008-01-01

    Eight muscles invest the human tongue: four extrinsic muscles have external origins and insert into the tongue body and four intrinsic muscles originate and terminate within the tongue. Previously, we noted minimal activation of the genioglossus tongue muscle during impeded protrusion tasks (i.e., having subjects push the tongue against a force transducer), suggesting that other muscles play a role in the production of tongue force. Accordingly, we sought to characterize genioglossus tongue m...

  15. Pleiotropic β-Agonist–Promoted Receptor Conformations and Signals Independent of Intrinsic Activity

    OpenAIRE

    2006-01-01

    β-Agonists used for treatment of obstructive lung disease have a variety of different structures but are typically classified by their intrinsic activities for stimulation of cAMP, and predictions are made concerning other downstream signals based on such a classification. We generated modified β2-adrenergic receptors with insertions of energy donor and acceptor moieties to monitor agonist-promoted conformational changes of the receptor using intramolecular bioluminescence resonance energy tr...

  16. Toxoplasma gondii: demonstration of intrinsic peroxidase activity during lacto-peroxidase mediated radioiodination of tachyzoites

    Energy Technology Data Exchange (ETDEWEB)

    Gallois, Y.; Tricaud, A.; Foussard, F.; Hodbert, J.; Girault, A.; Mauras, G.; Dubremetz, J.F.

    1986-01-01

    Tachyzoites of Toxoplasma gondii have been radioiodinated under various conditions with or without lactoperoxidase, with glucose oxidase being used to generate hydrogen peroxide. Erythrocytes were iodinated simultaneously as a control. In our conditions, tachyzoites were more intensely labelled in the absence of lactoperoxidase. This result can be explained by the existence of an intrinsic peroxidase activity which interfere with the exogenously added enzyme during surface radioiodination.

  17. Identification of intrinsic catalytic activity for electrochemical reduction of water molecules to generate hydrogen

    KAUST Repository

    Shinagawa, Tatsuya

    2015-01-01

    Insufficient hydronium ion activities at near-neutral pH and under unbuffered conditions induce diffusion-limited currents for hydrogen evolution, followed by a reaction with water molecules to generate hydrogen at elevated potentials. The observed constant current behaviors at near neutral pH reflect the intrinsic electrocatalytic reactivity of the metal electrodes for water reduction. This journal is © the Owner Societies.

  18. Image patch analysis of sunspots and active regions. I. Intrinsic dimension and correlation analysis

    Science.gov (United States)

    Moon, Kevin R.; Li, Jimmy J.; Delouille, Véronique; De Visscher, Ruben; Watson, Fraser; Hero, Alfred O.

    2016-01-01

    Context. The flare productivity of an active region is observed to be related to its spatial complexity. Mount Wilson or McIntosh sunspot classifications measure such complexity but in a categorical way, and may therefore not use all the information present in the observations. Moreover, such categorical schemes hinder a systematic study of an active region's evolution for example. Aims: We propose fine-scale quantitative descriptors for an active region's complexity and relate them to the Mount Wilson classification. We analyze the local correlation structure within continuum and magnetogram data, as well as the cross-correlation between continuum and magnetogram data. Methods: We compute the intrinsic dimension, partial correlation, and canonical correlation analysis (CCA) of image patches of continuum and magnetogram active region images taken from the SOHO-MDI instrument. We use masks of sunspots derived from continuum as well as larger masks of magnetic active regions derived from magnetogram to analyze separately the core part of an active region from its surrounding part. Results: We find relationships between the complexity of an active region as measured by its Mount Wilson classification and the intrinsic dimension of its image patches. Partial correlation patterns exhibit approximately a third-order Markov structure. CCA reveals different patterns of correlation between continuum and magnetogram within the sunspots and in the region surrounding the sunspots. Conclusions: Intrinsic dimension has the potential to distinguish simple from complex active regions. These results also pave the way for patch-based dictionary learning with a view toward automatic clustering of active regions.

  19. Effects of scanner acoustic noise on intrinsic brain activity during auditory stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yakunina, Natalia [Kangwon National University, Institute of Medical Science, School of Medicine, Chuncheon (Korea, Republic of); Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kang, Eun Kyoung [Kangwon National University Hospital, Department of Rehabilitation Medicine, Chuncheon (Korea, Republic of); Kim, Tae Su [Kangwon National University Hospital, Department of Otolaryngology, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of); Min, Ji-Hoon [University of Michigan, Department of Biopsychology, Cognition, and Neuroscience, Ann Arbor, MI (United States); Kim, Sam Soo [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Radiology, Chuncheon (Korea, Republic of); Nam, Eui-Cheol [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of)

    2015-10-15

    Although the effects of scanner background noise (SBN) during functional magnetic resonance imaging (fMRI) have been extensively investigated for the brain regions involved in auditory processing, its impact on other types of intrinsic brain activity has largely been neglected. The present study evaluated the influence of SBN on a number of intrinsic connectivity networks (ICNs) during auditory stimulation by comparing the results obtained using sparse temporal acquisition (STA) with those using continuous acquisition (CA). Fourteen healthy subjects were presented with classical music pieces in a block paradigm during two sessions of STA and CA. A volume-matched CA dataset (CAm) was generated by subsampling the CA dataset to temporally match it with the STA data. Independent component analysis was performed on the concatenated STA-CAm datasets, and voxel data, time courses, power spectra, and functional connectivity were compared. The ICA revealed 19 ICNs; the auditory, default mode, salience, and frontoparietal networks showed greater activity in the STA. The spectral peaks in 17 networks corresponded to the stimulation cycles in the STA, while only five networks displayed this correspondence in the CA. The dorsal default mode and salience networks exhibited stronger correlations with the stimulus waveform in the STA. SBN appeared to influence not only the areas of auditory response but also the majority of other ICNs, including attention and sensory networks. Therefore, SBN should be regarded as a serious nuisance factor during fMRI studies investigating intrinsic brain activity under external stimulation or task loads. (orig.)

  20. Green synthesis of bacterial mediated anti-proliferative gold nanoparticles: inducing mitotic arrest (G2/M phase) and apoptosis (intrinsic pathway).

    Science.gov (United States)

    Kumar, C Ganesh; Poornachandra, Y; Chandrasekhar, Cheemalamarri

    2015-11-28

    The physiochemical and biological properties of microbial derived gold nanoparticles have potential applications in various biomedical domains as well as in cancer therapy. We have fabricated anti-proliferative bacterial mediated gold nanoparticles (b-Au NPs) using a culture supernatant of Streptomyces clavuligerus and later characterized them by UV-visible, TEM, DLS, XRD and FT-IR spectroscopic techniques. The capping agent responsible for the nanoparticle formation was characterized based on SDS-PAGE and MALDI-TOF-MS analyses. They were tested for anticancer activity in A549, HeLa and DU145 cell lines. The biocompatibility and non-toxic nature of the nanoparticles were tested on normal human lung cell line (MRC-5). The b-Au NPs induced the cell cycle arrest in G2/M phase and also inhibited the microtubule assembly in DU145 cells. Mechanistic studies, such as ROS, MMP, Cyt-c, GSH, caspases 9, 8 and 3 activation and the Annexin V-FITC staining, along with the above parameters tested provided sufficient evidence that the b-Au NPs induced apoptosis through the intrinsic pathway. The results supported the use of b-Au NPs for future therapeutic application in cancer therapy and other biomedical applications.

  1. Advanced oxidation protein products induce chondrocyte apoptosis via receptor for advanced glycation end products-mediated, redox-dependent intrinsic apoptosis pathway.

    Science.gov (United States)

    Wu, Qian; Zhong, Zhao-Ming; Zhu, Si-Yuan; Liao, Cong-Rui; Pan, Ying; Zeng, Ji-Huan; Zheng, Shuai; Ding, Ruo-Ting; Lin, Qing-Song; Ye, Qing; Ye, Wen-Bin; Li, Wei; Chen, Jian-Ting

    2016-01-01

    Pro-inflammatory cytokine-induced chondrocyte apoptosis is a primary cause of cartilage destruction in the progression of rheumatoid arthritis (RA). Advanced oxidation protein products (AOPPs), a novel pro-inflammatory mediator, have been confirmed to accumulate in patients with RA. However, the effect of AOPPs accumulation on chondrocyte apoptosis and the associated cellular mechanisms remains unclear. The present study demonstrated that the plasma formation of AOPPs was enhanced in RA rats compared with normal. Then, chondrocyte were treated with AOPPs-modified rat serum albumin (AOPPs-RSA) in vitro. Exposure of chondrocyte to AOPPs activated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase and increased expression of NADPH oxidase subunits, which was mediated by receptor for advanced glycation end products (RAGE), but not scavenger receptor CD36. Moreover, AOPPs challenge triggered NADPH oxidase-dependent ROS generation which induced mitochondrial dysfunction and endoplasmic reticulum stress resulted in activation of caspase family that eventually lead to apoptosis. Lastly, blockade of RAGE, instead of CD36, largely attenuated these signals. Our study demonstrated first time that AOPPs induce chondrocyte apoptosis via RAGE-mediated and redox-dependent intrinsic apoptosis pathway in vitro. These data implicates that AOPPs may represent a novel pathogenic factor that contributes to RA progression. Targeting AOPPs-triggered cellular mechanisms might emerge as a promising therapeutic option for patients with RA.

  2. DMPD: Signaling pathways activated by microorganisms. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17303405 Signaling pathways activated by microorganisms. Takeuchi O, Akira S. Curr ...Opin Cell Biol. 2007 Apr;19(2):185-91. Epub 2007 Feb 15. (.png) (.svg) (.html) (.csml) Show Signaling pathwa...ys activated by microorganisms. PubmedID 17303405 Title Signaling pathways activated by microorganisms. Auth

  3. Image patch analysis of sunspots and active regions. I. Intrinsic dimension and correlation analysis

    CERN Document Server

    Moon, Kevin R; Delouille, Veronique; De Visscher, Ruben; Watson, Fraser; Hero, Alfred O

    2015-01-01

    Complexity of an active region is related to its flare-productivity. Mount Wilson or McIntosh sunspot classifications measure such complexity but in a categorical way, and may therefore not use all the information present in the observations. Moreover, such categorical schemes hinder a systematic study of an active region's evolution for example. We propose fine-scale quantitative descriptors for an active region's complexity and relate them to the Mount Wilson classification. We analyze the local correlation structure within continuum and magnetogram data, as well as the cross-correlation between continuum and magnetogram data. We compute the intrinsic dimension, partial correlation, and canonical correlation analysis (CCA) of image patches of continuum and magnetogram active region images taken from the SOHO-MDI instrument. We use masks of sunspots derived from continuum as well as larger masks of magnetic active regions derived from the magnetogram to analyze separately the core part of an active region fr...

  4. Predictive features of persistent activity emergence in regular spiking and intrinsic bursting model neurons.

    Science.gov (United States)

    Sidiropoulou, Kyriaki; Poirazi, Panayiota

    2012-01-01

    Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC), which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS) and an intrinsic bursting (IB) model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP) latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given stimulus that code

  5. Predictive features of persistent activity emergence in regular spiking and intrinsic bursting model neurons.

    Directory of Open Access Journals (Sweden)

    Kyriaki Sidiropoulou

    Full Text Available Proper functioning of working memory involves the expression of stimulus-selective persistent activity in pyramidal neurons of the prefrontal cortex (PFC, which refers to neural activity that persists for seconds beyond the end of the stimulus. The mechanisms which PFC pyramidal neurons use to discriminate between preferred vs. neutral inputs at the cellular level are largely unknown. Moreover, the presence of pyramidal cell subtypes with different firing patterns, such as regular spiking and intrinsic bursting, raises the question as to what their distinct role might be in persistent firing in the PFC. Here, we use a compartmental modeling approach to search for discriminatory features in the properties of incoming stimuli to a PFC pyramidal neuron and/or its response that signal which of these stimuli will result in persistent activity emergence. Furthermore, we use our modeling approach to study cell-type specific differences in persistent activity properties, via implementing a regular spiking (RS and an intrinsic bursting (IB model neuron. We identify synaptic location within the basal dendrites as a feature of stimulus selectivity. Specifically, persistent activity-inducing stimuli consist of activated synapses that are located more distally from the soma compared to non-inducing stimuli, in both model cells. In addition, the action potential (AP latency and the first few inter-spike-intervals of the neuronal response can be used to reliably detect inducing vs. non-inducing inputs, suggesting a potential mechanism by which downstream neurons can rapidly decode the upcoming emergence of persistent activity. While the two model neurons did not differ in the coding features of persistent activity emergence, the properties of persistent activity, such as the firing pattern and the duration of temporally-restricted persistent activity were distinct. Collectively, our results pinpoint to specific features of the neuronal response to a given

  6. On the intrinsic disorder status of the major players in programmed cell death pathways [v1; ref status: indexed, http://f1000r.es/1me

    Directory of Open Access Journals (Sweden)

    Alexey V Uversky

    2013-09-01

    Full Text Available Earlier computational and bioinformatics analysis of several large protein datasets across 28 species showed that proteins involved in regulation and execution of programmed cell death (PCD possess substantial amounts of intrinsic disorder. Based on the comprehensive analysis of these datasets by a wide array of modern bioinformatics tools it was concluded that disordered regions of PCD-related proteins are involved in a multitude of biological functions and interactions with various partners, possess numerous posttranslational modification sites, and have specific evolutionary patterns (Peng et al. 2013. This study extends our previous work by providing information on the intrinsic disorder status of some of the major players of the three major PCD pathways: apoptosis, autophagy, and necroptosis. We also present a detailed description of the disorder status and interactomes of selected proteins that are involved in the p53-mediated apoptotic signaling pathways.

  7. Perceptions of the activity, the social climate, and the self during group exercise classes regulate intrinsic satisfaction

    OpenAIRE

    Maher, Jaclyn P.; Gottschall, Jinger S.; Conroy, David E.

    2015-01-01

    Engaging in regular physical activity is a challenging task for many adults. Intrinsic satisfaction with exercise classes is thought to promote adherence to physical activity. This study examined the characteristics of exercise classes that impact within-person changes in intrinsic satisfaction over the course of an extended group exercise program. A 30-week physical activity trial was conducted with assessments at the end of each class. Community-living adults (n = 29) were instructed to com...

  8. Does Aerobic Exercise Influence Intrinsic Brain Activity? An Aerobic Exercise Intervention among Healthy Old Adults

    Directory of Open Access Journals (Sweden)

    Pär Flodin

    2017-08-01

    Full Text Available Previous studies have indicated that aerobic exercise could reduce age related decline in cognition and brain functioning. Here we investigated the effects of aerobic exercise on intrinsic brain activity. Sixty sedentary healthy males and females (64–78 years were randomized into either an aerobic exercise group or an active control group. Both groups recieved supervised training, 3 days a week for 6 months. Multimodal brain imaging data was acquired before and after the intervention, including 10 min of resting state brain functional magnetic resonance imaging (rs-fMRI and arterial spin labeling (ASL. Additionally, a comprehensive battery of cognitive tasks assessing, e.g., executive function and episodic memory was administered. Both the aerobic and the control group improved in aerobic capacity (VO2-peak over 6 months, but a significant group by time interaction confirmed that the aerobic group improved more. Contrary to our hypothesis, we did not observe any significant group by time interactions with regard to any measure of intrinsic activity. To further probe putative relationships between fitness and brain activity, we performed post hoc analyses disregarding group belongings. At baseline, VO2-peak was negativly related to BOLD-signal fluctuations (BOLDSTD in mid temporal areas. Over 6 months, improvements in aerobic capacity were associated with decreased connectivity between left hippocampus and contralateral precentral gyrus, and positively to connectivity between right mid-temporal areas and frontal and parietal regions. Independent component analysis identified a VO2-related increase in coupling between the default mode network and left orbitofrontal cortex, as well as a decreased connectivity between the sensorimotor network and thalamus. Extensive exploratory data analyses of global efficiency, connectome wide multivariate pattern analysis (connectome-MVPA, as well as ASL, did not reveal any relationships between aerobic fitness

  9. Amelioration of nandrolone decanoate-induced testicular and sperm toxicity in rats by taurine: effects on steroidogenesis, redox and inflammatory cascades, and intrinsic apoptotic pathway.

    Science.gov (United States)

    Ahmed, Maha A E

    2015-02-01

    The wide abuse of the anabolic steroid nandrolone decanoate by athletes and adolescents for enhancement of sporting performance and physical appearance may be associated with testicular toxicity and infertility. On the other hand, taurine; a free β-amino acid with remarkable antioxidant activity, is used in taurine-enriched beverages to boost the muscular power of athletes. Therefore, the purpose of this study was to investigate the mechanisms of the possible protective effects of taurine on nandrolone decanoate-induced testicular and sperm toxicity in rats. To achieve this aim, male Wistar rats were randomly distributed into four groups and administered either vehicle, nandrolone decanoate (10mg/kg/week, I.M.), taurine (100mg/kg/day, p.o.) or combination of taurine and nandrolone decanoate, for 8 successive weeks. Results of the present study showed that taurine reversed nandrolone decanoate-induced perturbations in sperm characteristics, normalized serum testosterone level, and restored the activities of the key steroidogenic enzymes; 3β-HSD, and 17β-HSD. Moreover, taurine prevented nandrolone decanoate-induced testicular toxicity and DNA damage by virtue of its antioxidant, anti-inflammatory, and anti-apoptotic effects. This was evidenced by taurine-induced modulation of testicular LDH-x activity, redox markers (MDA, NO, GSH contents, and SOD activity), inflammatory indices (TNF-α, ICAM-1 levels, and MMP-9 gene expression), intrinsic apoptotic pathway (cytochrome c gene expression and caspase-3 content), and oxidative DNA damage markers (8-OHdG level and comet assay). In conclusion, at the biochemical and histological levels, taurine attenuated nandrolone decanoate-induced poor sperm quality and testicular toxicity in rats. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Meiotic failure in cyclin A1-deficient mouse spermatocytes triggers apoptosis through intrinsic and extrinsic signaling pathways and 14-3-3 proteins

    Science.gov (United States)

    Panigrahi, Sunil K.; Manterola, Marcia; Wolgemuth, Debra J.

    2017-01-01

    Cyclin A1 (Ccna1), a member of the mammalian A type cyclins, is most abundantly expressed in spermatocytes and is essential for spermatogenesis in the mouse. Ccna1- deficient spermatocytes arrest at late meiotic prophase and undergo apoptosis. To further delineate the mechanisms and key factors involved in this process, we have examined changes in expression of genes involved in both intrinsic and extrinsic signaling pathways that trigger apoptosis in the mutant spermatocytes. Our results show that both pathways are involved, and that the factors involved in the intrinsic pathway were expressed earlier than those involved in the extrinsic pathway. We have also begun to identify in vivo Ccna1-interacting proteins, using an unbiased biochemical approach, and identified 14-3-3, a key regulator of apoptosis, as a Ccna1-interacting protein. Expression levels of 14-3-3 proteins remain unchanged between wild type and mutant testes but there were differences in the subcellular distribution. In wild type control, 14-3-3 is detected in both cytosolic and nuclear fractions whereas it is restricted to the cytoplasm in mutant testes. This differential distribution of 14-3-3 may contribute to the induction of apoptosis in Ccna1-deficient spermatocytes. These results provide insight into the apoptotic mechanisms and pathways that are triggered when progression through the meiotic cell cycle is defective in male gametogenesis. PMID:28301569

  11. Glioma cell death induced by irradiation or alkylating agent chemotherapy is independent of the intrinsic ceramide pathway.

    Directory of Open Access Journals (Sweden)

    Dorothee Gramatzki

    Full Text Available BACKGROUND/AIMS: Resistance to genotoxic therapy is a characteristic feature of glioma cells. Acid sphingomyelinase (ASM hydrolyzes sphingomyelin to ceramide and glucosylceramide synthase (GCS catalyzes ceramide metabolism. Increased ceramide levels have been suggested to enhance chemotherapy-induced death of cancer cells. METHODS: Microarray and clinical data for ASM and GCS in astrocytomas WHO grade II-IV were acquired from the Rembrandt database. Moreover, the glioblastoma database of the Cancer Genome Atlas network (TCGA was used for survival data of glioblastoma patients. For in vitro studies, increases in ceramide levels were achieved either by ASM overexpression or by the GCS inhibitor DL-threo-1-phenyl-2-palmitoylamino-3-morpholino-1-propanol (PPMP in human glioma cell lines. Combinations of alkylating chemotherapy or irradiation and ASM overexpression, PPMP or exogenous ceramide were applied in parental cells. The anti-glioma effects were investigated by assessing proliferation, metabolic activity, viability and clonogenicity. Finally, viability and clonogenicity were assessed in temozolomide (TMZ-resistant cells upon treatment with PPMP, exogenous ceramide, alkylating chemotherapy, irradiation or their combinations. RESULTS: Interrogations from the Rembrandt and TCGA database showed a better survival of glioblastoma patients with low expression of ASM or GCS. ASM overexpression or PPMP treatment alone led to ceramide accumulation but did not enhance the anti-glioma activity of alkylating chemotherapy or irradiation. PPMP or exogenous ceramide induced acute cytotoxicity in glioblastoma cells. Combined treatments with chemotherapy or irradiation led to additive, but not synergistic effects. Finally, no synergy was found when TMZ-resistant cells were treated with exogenous ceramide or PPMP alone or in combination with TMZ or irradiation. CONCLUSION: Modulation of intrinsic glioma cell ceramide levels by ASM overexpression or GCS

  12. Retinoic acid activates two pathways required for meiosis in mice.

    Directory of Open Access Journals (Sweden)

    Jana Koubova

    2014-08-01

    Full Text Available In all sexually reproducing organisms, cells of the germ line must transition from mitosis to meiosis. In mice, retinoic acid (RA, the extrinsic signal for meiotic initiation, activates transcription of Stra8, which is required for meiotic DNA replication and the subsequent processes of meiotic prophase. Here we report that RA also activates transcription of Rec8, which encodes a component of the cohesin complex that accumulates during meiotic S phase, and which is essential for chromosome synapsis and segregation. This RA induction of Rec8 occurs in parallel with the induction of Stra8, and independently of Stra8 function, and it is conserved between the sexes. Further, RA induction of Rec8, like that of Stra8, requires the germ-cell-intrinsic competence factor Dazl. Our findings strengthen the importance of RA and Dazl in the meiotic transition, provide important details about the Stra8 pathway, and open avenues to investigate early meiosis through analysis of Rec8 induction and function.

  13. Retinoic acid activates two pathways required for meiosis in mice.

    Directory of Open Access Journals (Sweden)

    Jana Koubova

    2014-08-01

    Full Text Available In all sexually reproducing organisms, cells of the germ line must transition from mitosis to meiosis. In mice, retinoic acid (RA, the extrinsic signal for meiotic initiation, activates transcription of Stra8, which is required for meiotic DNA replication and the subsequent processes of meiotic prophase. Here we report that RA also activates transcription of Rec8, which encodes a component of the cohesin complex that accumulates during meiotic S phase, and which is essential for chromosome synapsis and segregation. This RA induction of Rec8 occurs in parallel with the induction of Stra8, and independently of Stra8 function, and it is conserved between the sexes. Further, RA induction of Rec8, like that of Stra8, requires the germ-cell-intrinsic competence factor Dazl. Our findings strengthen the importance of RA and Dazl in the meiotic transition, provide important details about the Stra8 pathway, and open avenues to investigate early meiosis through analysis of Rec8 induction and function.

  14. Affinities and intrinsic activities of dopamine receptor agonists for the hD(21) and hD(4.4) receptors

    NARCIS (Netherlands)

    Lahti, RA; Mutin, A; Cochrane, EV; Tepper, PG; Dijkstra, D; Wikstrom, H; Tamminga, CA

    1996-01-01

    The affinity and intrinsic activity of dopamine receptor agonists were determined at the human dopamine hD(21) and hD(4.4) receptors. (-)-3-Hydroxy-N-n-propylpiperidine ((-)3-PPP) had an intrinsic activity of 46% and 83%, whereas (+)-N-propylnorapomorphine ((+)-NPA) had intrinsic activities of 61%

  15. Intrinsic activation of human motoneurons: possible contribution to motor unit excitation.

    Science.gov (United States)

    Gorassini, Monica; Yang, Jaynie F; Siu, Merek; Bennett, David J

    2002-04-01

    The main purpose of this study was to estimate the contribution of intrinsic activation of human motoneurons (e.g., by plateau potentials) during voluntary and reflexive muscle contractions. Pairs of motor units were recorded from either the tibialis anterior or soleus muscle during three different conditions: 1) during a brief muscle vibration followed by a slow relaxation of a steady isometric contraction; 2) during a triangular isometric torque contraction; and 3) during passive sinusoidal muscle stretch superimposed on a steady isometric contraction. In each case, the firing rate of a tonically firing control motor unit was used as a measure of the effective synaptic excitation (i.e., synaptic drive) to a slightly higher-threshold test motor unit that was recruited and de-recruited during a contraction trial. The firing rate of the control unit was compared at recruitment and de-recruitment of the test unit. This was done to determine whether the estimated synaptic drive needed to recruit a motor unit was less than the amount needed to sustain firing as a result of an added depolarization produced from intrinsic sources. After test unit recruitment, the firing rate of the control unit could be decreased significantly (on average by 3.6 Hz from an initial recruitment rate of 9.8 Hz) before the test unit was de-recruited during a descending synaptic drive. Similar decreases in control unit rate occurred in all three experimental conditions. This represents a possible 40% reduction in the estimated synaptic drive needed to maintain firing of a motor unit compared with the estimated amount needed to recruit the unit initially. The firing rates of both the control and test units were modulated together in a highly parallel fashion, suggesting that the unit pairs were driven by common synaptic inputs. This tight correlation further validated the use of the control unit firing rate as a monitor of synaptic drive to the test motor unit. The estimates of intrinsically

  16. Perceptions of the activity, the social climate, and the self during group exercise classes regulate intrinsic satisfaction.

    Science.gov (United States)

    Maher, Jaclyn P; Gottschall, Jinger S; Conroy, David E

    2015-01-01

    Engaging in regular physical activity is a challenging task for many adults. Intrinsic satisfaction with exercise classes is thought to promote adherence to physical activity. This study examined the characteristics of exercise classes that impact within-person changes in intrinsic satisfaction over the course of an extended group exercise program. A 30-week physical activity trial was conducted with assessments at the end of each class. Community-living adults (n = 29) were instructed to complete at least six group exercise classes each week and, following each exercise class, complete a questionnaire asking about the characteristics of the class and the participant's evaluation of the class. Intrinsic satisfaction was high, on average, but varied as much within-person from class-to-class as it did between exercisers. Participants reported the greatest intrinsic satisfaction when classes placed greater emphasis on exercisers' involvement with the group task, feelings of competence, and encouragement from the instructor. For the most part, exercise classes that were more intense than usual were perceived by exercisers as less intrinsically satisfying. Some overall characteristics of the exercise classes were also associated with intrinsic satisfaction. The social and motivational characteristics of group exercise classes contribute to exercisers' intrinsic satisfaction with classes and attention to those dynamics, as well as the intensity of the exercise, may improve adherence for exercise regimens.

  17. Reconstituting redox active centers of heme-containing proteins with biomineralized gold toward peroxidase mimics with strong intrinsic catalysis and electrocatalysis for H2O2 detection.

    Science.gov (United States)

    Zhang, Liyan; Li, Shuai; Dong, Minmin; Jiang, Yao; Li, Ru; Zhang, Shuo; Lv, Xiaoxia; Chen, Lijun; Wang, Hua

    2017-01-15

    A facile and efficient enzymatic reconstitution methodology has been proposed for high-catalysis peroxidase mimics by remolding the redox active centers of heme-containing proteins with the in-site biomineralized gold using hemoglobin (Hb) as a model. Catalytic hemin (Hem) was extracted from the active centers of Hb for the gold biomineralization and then reconstituted into apoHb to yield the Hem-Au@apoHb nanocomposites showing dramatically improved intrinsic catalysis and electrocatalysis over natural Hb and Hem. The biomineralized gold, on the one hand, would act as "nanowires" to promote the electron transferring of the nanocomposites. On the other hand, it would create a reactivity pathway to pre-organize and accumulate more substrates towards the active sites of the peroxidase mimics. Steady-state kinetics studies indicate that Hem-Au@apoHb could present much higher substrate affinity (lower Michaelis constants) and intrinsic catalysis even than some natural peroxidases. Moreover, the application feasibility of the prepared artificial enzymes was demonstrated by colorimetric assays and direct electrocatalysis for H2O2 sensing, showing a detection limitation low as 0.45μM. Importantly, such a catalysis active-center reconstitution protocol may circumvent the substantial improvement of the intrinsic catalysis and electrocatalysis of diverse heme-containing proteins or enyzmes toward the extensive applications in the chemical, enviromental, and biomedical catalysis fields.

  18. 1-Benzyl-2-Phenylbenzimidazole (BPB, a Benzimidazole Derivative, Induces Cell Apoptosis in Human Chondrosarcoma through Intrinsic and Extrinsic Pathways

    Directory of Open Access Journals (Sweden)

    Ju-Fang Liu

    2012-12-01

    Full Text Available In this study, we investigated the anticancer effects of a new benzimidazole derivative, 1-benzyl-2-phenyl -benzimidazole (BPB, in human chondrosarcoma cells. BPB-mediated apoptosis was assessed by the MTT assay and flow cytometry analysis. The in vivo efficacy was examined in a JJ012 xenograft model. Here we found that BPB induced apoptosis in human chondrosarcoma cell lines (JJ012 and SW1353 but not in primary chondrocytes. BPB induced upregulation of Bax, Bad and Bak, downregulation of Bcl-2, Bid and Bcl-XL and dysfunction of mitochondria in chondrosarcoma. In addition, BPB also promoted cytosolic releases AIF and Endo G. Furthermore, it triggered extrinsic death receptor-dependent pathway, which was characterized by activating Fas, FADD and caspase-8. Most importantly, animal studies revealed a dramatic 40% reduction in tumor volume after 21 days of treatment. Thus, BPB may be a novel anticancer agent for the treatment of chondrosarcoma.

  19. Slow State Transitions of Sustained Neural Oscillations by Activity-Dependent Modulation of Intrinsic Excitability

    Science.gov (United States)

    Fröhlich, Flavio; Bazhenov, Maxim; Timofeev, Igor; Steriade, Mircea; Sejnowski, Terrence J.

    2010-01-01

    Little is known about the dynamics and mechanisms of transitions between tonic firing and bursting in cortical networks. Here, we use a computational model of a neocortical circuit with extracellular potassium dynamics to show that activity-dependent modulation of intrinsic excitability can lead to sustained oscillations with slow transitions between two distinct firing modes: fast run (tonic spiking or fast bursts with few spikes) and slow bursting. These transitions are caused by a bistability with hysteresis in a pyramidal cell model. Balanced excitation and inhibition stabilizes a network of pyramidal cells and inhibitory interneurons in the bistable region and causes sustained periodic alternations between distinct oscillatory states. During spike-wave seizures, neocortical paroxysmal activity exhibits qualitatively similar slow transitions between fast run and bursting. We therefore predict that extracellular potassium dynamics can cause alternating episodes of fast and slow oscillatory states in both normal and epileptic neocortical networks. PMID:16763023

  20. Dynamic regulation of midbrain dopamine neuron activity: intrinsic, synaptic, and plasticity mechanisms.

    Science.gov (United States)

    Morikawa, H; Paladini, C A

    2011-12-15

    Although the roles of dopaminergic signaling in learning and behavior are well established, it is not fully understood how the activity of dopaminergic neurons is dynamically regulated under different conditions in a constantly changing environment. Dopamine neurons must integrate sensory, motor, and cognitive information online to inform the organism to pursue outcomes with the highest reward probability. In this article, we provide an overview of recent advances on the intrinsic, extrinsic (i.e., synaptic), and plasticity mechanisms controlling dopamine neuron activity, mostly focusing on mechanistic studies conducted using ex vivo brain slice preparations. We also hope to highlight some unresolved questions regarding information processing that takes place at dopamine neurons, thereby stimulating further investigations at different levels of analysis.

  1. Coordination of intrinsic and extrinsic hand muscle activity as a function of wrist joint angle during two-digit grasping.

    Science.gov (United States)

    Johnston, Jamie A; Bobich, Lisa R; Santello, Marco

    2010-04-26

    Fingertip forces result from the activation of muscles that cross the wrist and muscles whose origins and insertions reside within the hand (extrinsic and intrinsic hand muscles, respectively). Thus, tasks that involve changes in wrist angle affect the moment arm and length, hence the force-producing capabilities, of extrinsic muscles only. If a grasping task requires the exertion of constant fingertip forces, the Central Nervous System (CNS) may respond to changes in wrist angle by modulating the neural drive to extrinsic or intrinsic muscles only or by co-activating both sets of muscles. To distinguish between these scenarios, we recorded electromyographic (EMG) activity of intrinsic and extrinsic muscles of the thumb and index finger as a function of wrist angle during a two-digit object hold task. We hypothesized that changes in wrist angle would elicit EMG amplitude modulation of the extrinsic and intrinsic hand muscles. In one experimental condition we asked subjects to exert the same digit forces at each wrist angle, whereas in a second condition subjects could choose digit forces for holding the object. EMG activity was significantly modulated in both extrinsic and intrinsic muscles as a function of wrist angle (both pmuscles. We conclude that the CNS controlled both extrinsic and intrinsic muscles as a muscle synergy. These findings are discussed within the theoretical frameworks of synergies and common neural input across motor nuclei of hand muscles. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  2. [Specifics of perception of acoustic image of intrinsic bioelectric brain activity].

    Science.gov (United States)

    Konstantinov, K V; Leonova, M K; Miroshnikov, D B; Klimenko, V M

    2014-06-01

    We studied the particularities of perception of the acoustic image of intrinsic EEG. We found that the assessment of perception of sounds, the presentation of which was synchronized and was agreed with current bioelectric brain activity, is higher that assessment of perception of acoustic EEG image presented in recorded form. Presentation of recorded acoustic image of EEG is accompanied by increased activity of beta-band in the frontal areas, while real-time presentation of acoustic EEG image is accompanied by the increase of slow wave activity: theta- and delta-bands of occipital areas of the brain. Increase activity in theta- and delta-bands of occipital areas in sessions of hearing the acoustic image of EEG in real time depend on the baseline frequency structure of EEG and correlates with expression of alpha-, beta- and theta-bands of bioelectric brain activity in both frontal and occipital areas. We suppose that presentation of sounds synchronized and agreed with the current bioelectric activity, activated the regulatory brain structures.

  3. Rapid eye movement sleep loss induces neuronal apoptosis in the rat brain by noradrenaline acting on alpha 1-adrenoceptor and by triggering mitochondrial intrinsic pathway

    Directory of Open Access Journals (Sweden)

    Bindu I Somarajan

    2016-03-01

    cytochrome c to activate intrinsic pathway for inducing neuronal apoptosis in REMS deprived rat brain.

  4. The Intrinsic Eddington Ratio Distribution of Active Galactic Nuclei in Young Galaxies from SDSS

    Science.gov (United States)

    Jones, Mackenzie L.; Hickox, Ryan C.; Black, Christine; Hainline, Kevin Nicholas; DiPompeo, Michael A.

    2016-04-01

    An important question in extragalactic astronomy concerns the distribution of black hole accretion rates, i.e. the Eddington ratio distribution, of active galactic nuclei (AGN). Specifically, it is matter of debate whether AGN follow a broad distribution in accretion rates, or if the distribution is more strongly peaked at characteristic Eddington ratios. Using a sample of galaxies from SDSS DR7, we test whether an intrinsic Eddington ratio distribution that takes the form of a broad Schechter function is in fact consistent with previous work that suggests instead that young galaxies in optical surveys have a more strongly peaked lognormal Eddington ratio distribution. Furthermore, we present an improved method for extracting the AGN distribution using BPT diagnostics that allows us to probe over one order of magnitude lower in Eddington ratio, counteracting the effects of dilution by star formation. We conclude that the intrinsic Eddington ratio distribution of optically selected AGN is consistent with a power law with an exponential cutoff, as is observed in the X-rays. This work was supported in part by a NASA Jenkins Fellowship.

  5. Activated glucocorticoid and eicosanoid pathways in endometriosis.

    Science.gov (United States)

    Monsivais, Diana; Bray, Jeffrey D; Su, Emily; Pavone, Mary Ellen; Dyson, Matthew T; Navarro, Antonia; Kakinuma, Toshiyuki; Bulun, Serdar E

    2012-07-01

    To define altered gene expression networks in endometriosis. Experiments using endometriotic tissues and primary cells. Division of Reproductive Biology Research, Northwestern University. Premenopausal women. Matched samples of eutopic endometrium and ovarian endometriosis (n = 8 patients) were analyzed by microarray and verified in a separate set of tissues (n = 6 patients). Experiments to define signaling pathways were performed in primary endometriotic stromal cells (n = 12 patients). Using a genome-wide in vivo approach, we identified 1,366 differentially expressed genes and a new gene network favoring increased glucocorticoid levels and action in endometriosis. Transcript and protein levels of 11β-hydroxysteroid dehydrogenase (HSD11B1), which produces cortisol, the biologically active glucocorticoid, were strikingly higher, whereas messenger RNA (mRNA) levels of the cortisol-degrading HSD11B2 enzyme were significantly lower in endometriotic tissue. Glucocorticoid receptor mRNA and protein levels were significantly higher in endometriosis. The inflammatory cytokine tumor necrosis factor robustly induced mRNA and protein levels of HSD11B1 and glucocorticoid receptor but suppressed HSD11B2 mRNA in primary endometriotic stromal cells, suggesting that tumor necrosis factor stimulates cortisol production and action. We also uncovered a subset of genes critical for prostaglandin synthesis and degradation, which favor high eicosanoid levels and activity in endometriosis. The proinflammatory milieu of the endometriotic lesion stimulates cortisol synthesis and action in endometriotic lesions. Published by Elsevier Inc.

  6. Zelda overcomes the high intrinsic nucleosome barrier at enhancers during Drosophila zygotic genome activation.

    Science.gov (United States)

    Sun, Yujia; Nien, Chung-Yi; Chen, Kai; Liu, Hsiao-Yun; Johnston, Jeff; Zeitlinger, Julia; Rushlow, Christine

    2015-11-01

    The Drosophila genome activator Vielfaltig (Vfl), also known as Zelda (Zld), is thought to prime enhancers for activation by patterning transcription factors (TFs). Such priming is accompanied by increased chromatin accessibility, but the mechanisms by which this occurs are poorly understood. Here, we analyze the effect of Zld on genome-wide nucleosome occupancy and binding of the patterning TF Dorsal (Dl). Our results show that early enhancers are characterized by an intrinsically high nucleosome barrier. Zld tackles this nucleosome barrier through local depletion of nucleosomes with the effect being dependent on the number and position of Zld motifs. Without Zld, Dl binding decreases at enhancers and redistributes to open regions devoid of enhancer activity. We propose that Zld primes enhancers by lowering the high nucleosome barrier just enough to assist TFs in accessing their binding motifs and promoting spatially controlled enhancer activation if the right patterning TFs are present. We envision that genome activators in general will utilize this mechanism to activate the zygotic genome in a robust and precise manner.

  7. Intrinsic Levanase Activity of Bacillus subtilis 168 Levansucrase (SacB.

    Directory of Open Access Journals (Sweden)

    Luz Méndez-Lorenzo

    Full Text Available Levansucrase catalyzes the synthesis of fructose polymers through the transfer of fructosyl units from sucrose to a growing fructan chain. Levanase activity of Bacillus subtilis levansucrase has been described since the very first publications dealing with the mechanism of levan synthesis. However, there is a lack of qualitative and quantitative evidence regarding the importance of the intrinsic levan hydrolysis of B. subtilis levansucrase and its role in the levan synthesis process. Particularly, little attention has been paid to the long-term hydrolysis products, including its participation in the final levan molecules distribution. Here, we explored the hydrolytic and transferase activity of the B. subtilis levansucrase (SacB when levans produced by the same enzyme are used as substrate. We found that levan is hydrolyzed through a first order exo-type mechanism, which is limited to a conversion extent of around 30% when all polymer molecules reach a structure no longer suitable to SacB hydrolysis. To characterize the reaction, Isothermal Titration Calorimetry (ITC was employed and the evolution of the hydrolysis products profile followed by HPLC, GPC and HPAEC-PAD. The ITC measurements revealed a second step, taking place at the end of the reaction, most probably resulting from disproportionation of accumulated fructo-oligosaccharides. As levanase, levansucrase may use levan as substrate and, through a fructosyl-enzyme complex, behave as a hydrolytic enzyme or as a transferase, as demonstrated when glucose and fructose are added as acceptors. These reactions result in a wide variety of oligosaccharides that are also suitable acceptors for fructo-oligosaccharide synthesis. Moreover, we demonstrate that SacB in the presence of levan and glucose, through blastose and sucrose synthesis, results in the same fructooligosaccharides profile as that observed in sucrose reactions. We conclude that SacB has an intrinsic levanase activity that

  8. Siamese crocodile bile induces apoptosis in NCI-H1299 human non-small cell lung cancer cells via a mitochondria-mediated intrinsic pathway and inhibits tumorigenesis.

    Science.gov (United States)

    Tian, Ling; Deng, Yi-Tao; Dong, Xin; Fan, Jia-Yi; Li, Hua-Liang; Ding, Yu-Mei; Peng, Wei-Xi; Chen, Qing-Xi; Shen, Dong-Yan

    2017-04-01

    Non-small-cell lung cancer (NSCLC) is a widespread and particularly aggressive form of cancer. Patients with NSCLC and early metastases typically have poor prognosis, highlighting the critical need for additional drugs to improve disease outcome following surgical resection. The present study aimed to determine if Siamese crocodile bile (SCB) had an anti‑cancer effect on NCI‑H1299 human NSCLC cells. The inhibitory mechanism of SCB was examined in cell culture and nude mice. In vitro experimental results revealed that SCB inhibited the proliferation and colony‑forming ability of NCI‑H1299 cells by arresting cell cycle and inducing apoptosis. The loss of the mitochondrial membrane potential and the release of cytochrome c indicated that SCB treatment may lead to mitochondrial dysfunction in NCI‑H1299 cells. At the molecular level, SCB altered the ratio of protein expression of Bax/Bcl‑2 and activated associated caspases, suggesting that intrinsic pathway involvement in the SCB‑induced apoptosis of NCI‑H1299 cells. In the in vivo experiments, intraperitoneal injection of SCB for 4 weeks inhibited xenograft tumor growth by 46.8% without observable toxicity in nude mice. Immunohistochemistry analysis of proliferating cell nuclear antigen and vascular endothelial growth factor also revealed that SCB inhibited cell proliferation and metastasis in NSCLC xenograft tumors. Overall, SCB exerted an anti-cancer effect on NCI‑H1299 human NSCLC cells in vitro and in vivo and may have therapeutic potential for the treatment of human NSCLC.

  9. Ethanolic extract of Thevetia peruviana flowers enhances TNF-α and TRAIL-induced apoptosis of human cervical cancer cells via intrinsic and extrinsic pathways.

    Science.gov (United States)

    Managit, Chittima; Sakurai, Hiroaki; Saiki, Ikuo

    2017-04-01

    Tumor necrosis factor-α (TNF-α) and TNF-related apoptosis-inducing ligand (TRAIL) are promising candidates for cancer treatment due to their ability to induce apoptosis through death receptor stimulation. However, their usage may be limited due to the resistance of cancer cells to TNF-α- and TRAIL-induced apoptosis. Currently, there is interest in screening for natural products that can sensitize cancer cells to TNF-α- and TRAIL-induced apoptosis for their use in combination with TNF-α or TRAIL. It was previously reported that the bark extract of Thevetia peruviana showed a reversal effect on TRAIL-resistance in human gastric adenocarcinoma cell lines. In the present study, the effects of the ethanolic extract of T. peruviana flowers on TNF-α- and TRAIL-induced apoptosis of human cervical cancer HeLa cells were investigated in vitro by determining cell viability and apoptosis using a WST-1 cell proliferation assay and immunoblot analysis, respectively. The ethanolic extract of T. peruviana flowers promoted TNF-α and TRAIL-mediated cell death through the activation of the caspase cascade, poly(ADP-ribose) polymerase and BH3-interacting domain death agonist cleavage. Combined treatment using the extract plus TNF-α resulted in downregulation of anti-apoptotic protein, including myeloid cell leukemia sequence-1, B-cell lymphoma-extra large (Bcl-XL), X-linked inhibitor of apoptosis protein and survivin, while the combined treatment with TRAIL downregulated Bcl-XL. Thus, the ethanolic extract of T. peruviana flowers has potential in sensitizing the TNF-α- and TRAIL-induced apoptosis of HeLa cells via the intrinsic and extrinsic pathways.

  10. PERK Utilizes Intrinsic Lipid Kinase Activity To Generate Phosphatidic Acid, Mediate Akt Activation, and Promote Adipocyte Differentiation

    Science.gov (United States)

    Bobrovnikova-Marjon, Ekaterina; Pytel, Dariusz; Riese, Matthew J.; Vaites, Laura Pontano; Singh, Nickpreet; Koretzky, Gary A.; Witze, Eric S.

    2012-01-01

    The endoplasmic reticulum (ER) resident PKR-like kinase (PERK) is necessary for Akt activation in response to ER stress. We demonstrate that PERK harbors intrinsic lipid kinase, favoring diacylglycerol (DAG) as a substrate and generating phosphatidic acid (PA). This activity of PERK correlates with activation of mTOR and phosphorylation of Akt on Ser473. PERK lipid kinase activity is regulated in a phosphatidylinositol 3-kinase (PI3K) p85α-dependent manner. Moreover, PERK activity is essential during adipocyte differentiation. Because PA and Akt regulate many cellular functions, including cellular survival, proliferation, migratory responses, and metabolic adaptation, our findings suggest that PERK has a more extensive role in insulin signaling, insulin resistance, obesity, and tumorigenesis than previously thought. PMID:22493067

  11. PERK utilizes intrinsic lipid kinase activity to generate phosphatidic acid, mediate Akt activation, and promote adipocyte differentiation.

    Science.gov (United States)

    Bobrovnikova-Marjon, Ekaterina; Pytel, Dariusz; Riese, Matthew J; Vaites, Laura Pontano; Singh, Nickpreet; Koretzky, Gary A; Witze, Eric S; Diehl, J Alan

    2012-06-01

    The endoplasmic reticulum (ER) resident PKR-like kinase (PERK) is necessary for Akt activation in response to ER stress. We demonstrate that PERK harbors intrinsic lipid kinase, favoring diacylglycerol (DAG) as a substrate and generating phosphatidic acid (PA). This activity of PERK correlates with activation of mTOR and phosphorylation of Akt on Ser473. PERK lipid kinase activity is regulated in a phosphatidylinositol 3-kinase (PI3K) p85α-dependent manner. Moreover, PERK activity is essential during adipocyte differentiation. Because PA and Akt regulate many cellular functions, including cellular survival, proliferation, migratory responses, and metabolic adaptation, our findings suggest that PERK has a more extensive role in insulin signaling, insulin resistance, obesity, and tumorigenesis than previously thought.

  12. Polyphenol oxidase activity as a potential intrinsic index of adequate thermal pasteurization of apple cider.

    Science.gov (United States)

    Chen, L; Ingham, B H; Ingham, S C

    2004-05-01

    In response to increasing concerns about microbial safety of apple cider, the U.S. Food and Drug Administration has mandated treatment of cider sufficient for a 5-log reduction of the target pathogen. Pasteurization has been suggested as the treatment most likely to achieve a 5-log reduction, with Escherichia coli O157:H7 as the target pathogen. Regulators and processors need a reliable method for verifying pasteurization, and apple cider polyphenol oxidase (PPO) activity was studied as a potential intrinsic index for thermal pasteurization. The effect of pasteurization conditions and apple cider properties on PPO activity and survival of three pathogens (E. coli O157:H7, Salmonella, and Listeria monocytogenes) was studied using a Box-Behnken response surface design. Factors considered in the design were pasteurization conditions, i.e., hold temperature (60, 68, and 76 degrees C), preheat time (10, 20, 30 s), and hold time (0, 15, 30 s), pH, and sugar content ((o)Brix) of apple cider. Response surface contour plots were constructed to illustrate the effect of these factors on PPO activity and pathogen survival. Reduction in PPO activity of at least 50% was equivalent to a 5-log reduction in E. coli O157:H7 or L. monocytogenes for cider at pH 3.7 and 12.5 (o)Brix. Further studies, however, are needed to verify the relationship between PPO activity and pathogen reduction in cider with various pH and (o)Brix values.

  13. A Subtype of Inhibitory Interneuron with Intrinsic Persistent Activity in Human and Monkey Neocortex

    Directory of Open Access Journals (Sweden)

    Bo Wang

    2015-03-01

    Full Text Available A critical step in understanding the neural basis of human cognitive functions is to identify neuronal types in the neocortex. In this study, we performed whole-cell recording from human cortical slices and found a distinct subpopulation of neurons with intrinsic persistent activity that could be triggered by single action potentials (APs but terminated by bursts of APs. This persistent activity was associated with a depolarizing plateau potential induced by the activation of a persistent Na+ current. Single-cell RT-PCR revealed that these neurons were inhibitory interneurons. This type of neuron was found in different cortical regions, including temporal, frontal, occipital, and parietal cortices in human and also in frontal and temporal lobes of nonhuman primate but not in rat cortical tissues, suggesting that it could be unique to primates. The characteristic persistent activity in these inhibitory interneurons may contribute to the regulation of pyramidal cell activity and participate in cortical processing.

  14. Amelioration of nandrolone decanoate-induced testicular and sperm toxicity in rats by taurine: Effects on steroidogenesis, redox and inflammatory cascades, and intrinsic apoptotic pathway

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Maha A.E., E-mail: mahapharm@yahoo.com

    2015-02-01

    The wide abuse of the anabolic steroid nandrolone decanoate by athletes and adolescents for enhancement of sporting performance and physical appearance may be associated with testicular toxicity and infertility. On the other hand, taurine; a free β-amino acid with remarkable antioxidant activity, is used in taurine-enriched beverages to boost the muscular power of athletes. Therefore, the purpose of this study was to investigate the mechanisms of the possible protective effects of taurine on nandrolone decanoate-induced testicular and sperm toxicity in rats. To achieve this aim, male Wistar rats were randomly distributed into four groups and administered either vehicle, nandrolone decanoate (10 mg/kg/week, I.M.), taurine (100 mg/kg/day, p.o.) or combination of taurine and nandrolone decanoate, for 8 successive weeks. Results of the present study showed that taurine reversed nandrolone decanoate-induced perturbations in sperm characteristics, normalized serum testosterone level, and restored the activities of the key steroidogenic enzymes; 3β-HSD, and 17β-HSD. Moreover, taurine prevented nandrolone decanoate-induced testicular toxicity and DNA damage by virtue of its antioxidant, anti-inflammatory, and anti-apoptotic effects. This was evidenced by taurine-induced modulation of testicular LDH-x activity, redox markers (MDA, NO, GSH contents, and SOD activity), inflammatory indices (TNF-α, ICAM-1 levels, and MMP-9 gene expression), intrinsic apoptotic pathway (cytochrome c gene expression and caspase-3 content), and oxidative DNA damage markers (8-OHdG level and comet assay). In conclusion, at the biochemical and histological levels, taurine attenuated nandrolone decanoate-induced poor sperm quality and testicular toxicity in rats. - Highlights: • Nandrolone decanoate (ND) disrupts sperm profile and steroidogenesis in rats. • ND upregulates gene expression of inflammatory and apoptotic markers. • Taurine normalizes sperm profile and serum testosterone level

  15. Intrinsic muscle strength and voluntary activation of both lower limbs and functional performance after stroke.

    Science.gov (United States)

    Horstman, Astrid M; Beltman, Marijke J; Gerrits, Karin H; Koppe, Peter; Janssen, Thomas W; Elich, Peter; de Haan, Arnold

    2008-07-01

    The objective of this study was to assess the nature of muscle weakness in both legs after stroke compared with able-bodied control individuals and to examine whether there is a relationship between the degree of muscle weakness and coactivation of knee extensors and flexors as well as voluntary activation capacity of knee extensors of both paretic and non-paretic legs and indices of functional performance. Maximal voluntary isometric torques of knee extensors (MVCe) and flexors (MVCf) were determined in 14 patients (bilaterally) and 12 able-bodied controls. Simultaneous measurements were made of torque and surface EMG from agonist and antagonist muscles. Coactivation was calculated. Supramaximal triplets were evoked with electrical stimulation to estimate maximal torque capacity and degree of voluntary activation of knee extensors. MVCs, activation and coactivation parameters were correlated to scores of seven functional performance tests. MVCe, MVCf and voluntary activation were lower in paretic lower limb (PL) compared with both non-paretic lower limb (NL) and control. Besides, all these parameters of NL were also lower than control. Electrically evoked torque capacity of knee extensors of PL was about 60% of both NL and control, which were not significantly different from each other. Strong significant correlations between strength, as well as voluntary activation, and functional performance were found. Coactivation did not correlate well with functional performance. Thus, whereas for NL activation failure can explain weakness, for PL both activation failure and reduced intrinsic torque capacity are responsible for the severe weakness. Activation capacity and muscle strength correlated strongly to functional performance, while coactivation did not.

  16. Increased Efferent Cardiac Sympathetic Nerve Activity and Defective Intrinsic Heart Rate Regulation in Type 2 Diabetes.

    Science.gov (United States)

    Thaung, H P Aye; Baldi, J Chris; Wang, Heng-Yu; Hughes, Gillian; Cook, Rosalind F; Bussey, Carol T; Sheard, Phil W; Bahn, Andrew; Jones, Peter P; Schwenke, Daryl O; Lamberts, Regis R

    2015-08-01

    Elevated sympathetic nerve activity (SNA) coupled with dysregulated β-adrenoceptor (β-AR) signaling is postulated as a major driving force for cardiac dysfunction in patients with type 2 diabetes; however, cardiac SNA has never been assessed directly in diabetes. Our aim was to measure the sympathetic input to and the β-AR responsiveness of the heart in the type 2 diabetic heart. In vivo recording of SNA of the left efferent cardiac sympathetic branch of the stellate ganglion in Zucker diabetic fatty rats revealed an elevated resting cardiac SNA and doubled firing rate compared with nondiabetic rats. Ex vivo, in isolated denervated hearts, the intrinsic heart rate was markedly reduced. Contractile and relaxation responses to β-AR stimulation with dobutamine were compromised in externally paced diabetic hearts, but not in diabetic hearts allowed to regulate their own heart rate. Protein levels of left ventricular β1-AR and Gs (guanine nucleotide binding protein stimulatory) were reduced, whereas left ventricular and right atrial β2-AR and Gi (guanine nucleotide binding protein inhibitory regulatory) levels were increased. The elevated resting cardiac SNA in type 2 diabetes, combined with the reduced cardiac β-AR responsiveness, suggests that the maintenance of normal cardiovascular function requires elevated cardiac sympathetic input to compensate for changes in the intrinsic properties of the diabetic heart. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  17. Gadolinium chloride elicits apoptosis in human osteosarcoma U-2 OS cells through extrinsic signaling, intrinsic pathway and endoplasmic reticulum stress.

    Science.gov (United States)

    Tsai, Yuh-Feng; Huang, Ching-Wen; Chiang, Jo-Hua; Tsai, Fuu-Jen; Hsu, Yuan-Man; Lu, Chi-Cheng; Hsiao, Chen-Yu; Yang, Jai-Sing

    2016-12-01

    Gadolinium (Gd) compounds are important as magnetic resonance imaging (MRI) contrast agents, and are potential anticancer agents. However, no report has shown the effect of gadolinium chloride (GdCl3) on osteosarcoma in vitro. The present study investigated the apoptotic mechanism of GdCl3 on human osteosarcoma U-2 OS cells. Our results indicated that GdCl3 significantly reduced cell viability of U-2 OS cells in a concentration-dependent manner. GdCl3 led to apoptotic cell shrinkage and DNA fragmentation in U-2 OS cells as revealed by morphologic changes and TUNEL staining. Colorimetric assay analyses also showed that activities of caspase-3, caspase-8, caspase-9 and caspase-4 occurred in GdCl3-treated U-2 OS cells. Pretreatment of cells with pan-caspase inhibitor (Z-VAD-FMK) and specific inhibitors of caspase-3/-8/-9 significantly reduced cell death caused by GdCl3. The increase of cytoplasmic Ca2+ level, ROS production and the decrease of mitochondria membrane potential (ΔΨm) were observed by flow cytometric analysis in U-2 OS cells after GdCl3 exposure. Western blot analyses demonstrated that the levels of Fas, FasL, cytochrome c, Apaf-1, GADD153 and GRP78 were upregulated in GdCl3-treated U-2 OS cells. In conclusion, death receptor, mitochondria-dependent and endoplasmic reticulum (ER) stress pathways contribute to GdCl3-induced apoptosis in U-2 OS cells. GdCl3 might have potential to be used in treatment of osteosarcoma patients.

  18. From computational modelling of the intrinsic apoptosis pathway to a systems-based analysis of chemotherapy resistance: achievements, perspectives and challenges in systems medicine.

    Science.gov (United States)

    Würstle, M L; Zink, E; Prehn, J H M; Rehm, M

    2014-01-01

    Our understanding of the mitochondrial or intrinsic apoptosis pathway and its role in chemotherapy resistance has increased significantly in recent years by a combination of experimental studies and mathematical modelling. This combined approach enhanced the quantitative and kinetic understanding of apoptosis signal transduction, but also provided new insights that systems-emanating functions (i.e., functions that cannot be attributed to individual network components but that are instead established by multi-component interplay) are crucial determinants of cell fate decisions. Among these features are molecular thresholds, cooperative protein functions, feedback loops and functional redundancies that provide systems robustness, and signalling topologies that allow ultrasensitivity or switch-like responses. The successful development of kinetic systems models that recapitulate biological signal transduction observed in living cells have now led to the first translational studies, which have exploited and validated such models in a clinical context. Bottom-up strategies that use pathway models in combination with higher-level modelling at the tissue, organ and whole body-level therefore carry great potential to eventually deliver a new generation of systems-based diagnostic tools that may contribute to the development of personalised and predictive medicine approaches. Here we review major achievements in the systems biology of intrinsic apoptosis signalling, discuss challenges for further model development, perspectives for higher-level integration of apoptosis models and finally discuss requirements for the development of systems medical solutions in the coming years.

  19. Id2a functions to limit Notch pathway activity and thereby influence the transition from proliferation to differentiation of retinoblasts during zebrafish retinogenesis.

    Science.gov (United States)

    Uribe, Rosa A; Kwon, Taejoon; Marcotte, Edward M; Gross, Jeffrey M

    2012-11-15

    During vertebrate retinogenesis, the precise balance between retinoblast proliferation and differentiation is spatially and temporally regulated through a number of intrinsic factors and extrinsic signaling pathways. Moreover, there are complex gene regulatory network interactions between these intrinsic factors and extrinsic pathways, which ultimately function to determine when retinoblasts exit the cell cycle and terminally differentiate. We recently uncovered a cell non-autonomous role for the intrinsic HLH factor, Id2a, in regulating retinoblast proliferation and differentiation, with Id2a-deficient retinae containing an abundance of proliferative retinoblasts and an absence of terminally differentiated retinal neurons and glia. Here, we report that Id2a function is necessary and sufficient to limit Notch pathway activity during retinogenesis. Id2a-deficient retinae possess elevated levels of Notch pathway component gene expression, while retinae overexpressing id2a possess reduced expression of Notch pathway component genes. Attenuation of Notch signaling activity by DAPT or by morpholino knockdown of Notch1a is sufficient to rescue both the proliferative and differentiation defects in Id2a-deficient retinae. In addition to regulating Notch pathway activity, through a novel RNA-Seq and differential gene expression analysis of Id2a-deficient retinae, we identify a number of additional intrinsic and extrinsic regulatory pathway components whose expression is regulated by Id2a. These data highlight the integral role played by Id2a in the gene regulatory network governing the transition from retinoblast proliferation to terminal differentiation during vertebrate retinogenesis.

  20. Intranasal exposure to amorphous nanosilica particles could activate intrinsic coagulation cascade and platelets in mice

    Science.gov (United States)

    2013-01-01

    Background Nanomaterials with particle sizes coagulation system. Methods We used nanosilica particles with diameters of 30, 70, or 100 nm (nSP30, nSP70, or nSP100 respectively), and conventional microscale silica particles with diameters of 300 or 1000 nm (mSP300 or mSP1000, respectively). BALB/c mice were intranasally exposed to nSP30, nSP70, nSP100, mSP300, or mSP1000 at concentrations of 500 μg/mouse for 7 days. After 24 hours of last administration, we performed the in vivo transmission electron microscopy analysis, hematological examination and coagulation tests. Results In vivo transmission electron microscopy analysis showed that nanosilica particles with a diameter coagulation tests showed that platelet counts decreased and that the activated partial thromboplastin time was prolonged in nSP30 or nSP70-treated groups of mice, indicating that nanosilica particles might have activated a coagulation cascade. In addition, in in vitro activation tests of human plasma, nanosilica particles had greater potential than did conventional microscale silica particles to activate coagulation factor XII. In nanosilica-particle-treated groups, the levels of soluble CD40 ligand, and von Willebrand factor which are involved in stimulating platelets tended to slightly increase with decreasing particle size. Conclusions These results suggest that intranasally administered nanosilica particles with diameters of 30 and 70 nm could induce abnormal activation of the coagulation system through the activation of an intrinsic coagulation cascade. This study provides information to advance the development of safe and effective nanosilica particles. PMID:23958113

  1. Alloying Au surface with Pd reduces the intrinsic activity in catalyzing CO oxidation

    KAUST Repository

    Qian, Kun

    2016-03-30

    © 2016. Various Au-Pd/SiO2 catalysts with a fixed Au loading but different Au:Pd molar ratios were prepared via deposition-precipitation method followed by H2 reduction. The structures were characterized and the catalytic activities in CO oxidation were evaluated. The formation of Au-Pd alloy particles was identified. The Au-Pd alloy particles exhibit enhanced dispersions on SiO2 than Au particles. Charge transfer from Pd to Au within Au-Pd alloy particles. Isolated Pd atoms dominate the surface of Au-Pd alloy particles with large Au:Pd molar ratios while contiguous Pd atoms dominate the surface of Au-Pd alloy particles with small Au:Pd molar ratios. Few synergetic effect of Au-Pd alloy occurs on catalyzing CO oxidation under employed reaction conditions. Alloying Au with Pd reduces the intrinsic activity in catalyzing CO oxidation, and contiguous Pd atoms on the Au-Pd alloy particles are capable of catalyzing CO oxidation while isolated Pd atoms are not. These results advance the fundamental understandings of Au-Pd alloy surfaces in catalyzing CO oxidation.

  2. Camphene isolated from essential oil of Piper cernuum (Piperaceae) induces intrinsic apoptosis in melanoma cells and displays antitumor activity in vivo.

    Science.gov (United States)

    Girola, Natalia; Figueiredo, Carlos R; Farias, Camyla F; Azevedo, Ricardo A; Ferreira, Adilson K; Teixeira, Sarah F; Capello, Tabata M; Martins, Euder G A; Matsuo, Alisson L; Travassos, Luiz R; Lago, João H G

    2015-11-27

    Natural monoterpenes were isolated from the essential oil of Piper cernuum Vell. (Piperaceae) leaves. The crude oil and the individual monoterpenes were tested for cytotoxicity in human tumor cell lineages and B16F10-Nex2 murine melanoma cells. In the present work we demonstrate the activity of camphene against different cancer cells, with its mechanism of action being investigated in vitro and in vivo in murine melanoma. Camphene induced apoptosis by the intrinsic pathway in melanoma cells mainly by causing endoplasmic reticulum (ER) stress, with release of Ca(2+) together with HmgB1 and calreticulin, loss of mitochondrial membrane potential and up regulation of caspase-3 activity. Importantly, camphene exerted antitumor activity in vivo by inhibiting subcutaneous tumor growth of highly aggressive melanoma cells in a syngeneic model, suggesting a promising role of this compound in cancer therapy.

  3. Essential role of the m2R-RGS6-IKACh pathway in controlling intrinsic heart rate variability.

    Directory of Open Access Journals (Sweden)

    Ekaterina Posokhova

    Full Text Available Normal heart function requires generation of a regular rhythm by sinoatrial pacemaker cells and the alteration of this spontaneous heart rate by the autonomic input to match physiological demand. However, the molecular mechanisms that ensure consistent periodicity of cardiac contractions and fine tuning of this process by autonomic system are not completely understood. Here we examined the contribution of the m2R-I(KACh intracellular signaling pathway, which mediates the negative chronotropic effect of parasympathetic stimulation, to the regulation of the cardiac pacemaking rhythm. Using isolated heart preparations and single-cell recordings we show that the m2R-I(KACh signaling pathway controls the excitability and firing pattern of the sinoatrial cardiomyocytes and determines variability of cardiac rhythm in a manner independent from the autonomic input. Ablation of the major regulator of this pathway, Rgs6, in mice results in irregular cardiac rhythmicity and increases susceptibility to atrial fibrillation. We further identify several human subjects with variants in the RGS6 gene and show that the loss of function in RGS6 correlates with increased heart rate variability. These findings identify the essential role of the m2R-I(KACh signaling pathway in the regulation of cardiac sinus rhythm and implicate RGS6 in arrhythmia pathogenesis.

  4. Essential Role of the m2R-RGS6-IKACh Pathway in Controlling Intrinsic Heart Rate Variability

    Science.gov (United States)

    Posokhova, Ekaterina; Ng, David; Opel, Aaisha; Masuho, Ikuo; Tinker, Andrew; Biesecker, Leslie G.; Wickman, Kevin; Martemyanov, Kirill A.

    2013-01-01

    Normal heart function requires generation of a regular rhythm by sinoatrial pacemaker cells and the alteration of this spontaneous heart rate by the autonomic input to match physiological demand. However, the molecular mechanisms that ensure consistent periodicity of cardiac contractions and fine tuning of this process by autonomic system are not completely understood. Here we examined the contribution of the m2R-IKACh intracellular signaling pathway, which mediates the negative chronotropic effect of parasympathetic stimulation, to the regulation of the cardiac pacemaking rhythm. Using isolated heart preparations and single-cell recordings we show that the m2R-IKACh signaling pathway controls the excitability and firing pattern of the sinoatrial cardiomyocytes and determines variability of cardiac rhythm in a manner independent from the autonomic input. Ablation of the major regulator of this pathway, Rgs6, in mice results in irregular cardiac rhythmicity and increases susceptibility to atrial fibrillation. We further identify several human subjects with variants in the RGS6 gene and show that the loss of function in RGS6 correlates with increased heart rate variability. These findings identify the essential role of the m2R-IKACh signaling pathway in the regulation of cardiac sinus rhythm and implicate RGS6 in arrhythmia pathogenesis. PMID:24204714

  5. Intrinsic Optical Activity and Environmental Perturbations: Solvation Effects in Chiral Building Blocks

    Science.gov (United States)

    Lemler, Paul M.; Vaccaro, Patrick

    2016-06-01

    The non-resonant interaction of electromagnetic radiation with an isotropic ensemble of chiral molecules, which causes the incident state of linear polarization to undergo a signed rotation, long has served as a metric for gauging the enantiomeric purity of asymmetric syntheses. While the underlying phenomenon of circular birefringence (CB) typically is probed in the condensed phase, recent advances in ultrasensitive circular-differential detection schemes, as exemplified by the techniques of Cavity Ring-Down Polarimetry (CRDP), have permitted the first quantitative analyses of such processes to be performed in rarefied media. Efforts to extend vapor-phase investigations of CB to new families of chiral substrates will be discussed, with particular emphasis directed towards the elucidation of intrinsic (e.g., solvent-free) properties and their mediation by environmental perturbations (e.g., solvation). Specific species targeted by this work will include the stereoselective building blocks phenylpropylene oxide and α-methylbenzyl amine, both of which exhibit pronounced solvent-dependent changes in measured optical activity. The nature of chiroptical response in different environments will be highlighted, with quantum-chemical calculations serving to unravel the structural and electronic provenance of observed behavior.

  6. Intrinsic Brain Activity Responsible for Sex Differences in Shyness and Social Anxiety

    Science.gov (United States)

    Yang, Xun; Zhou, Ming; Lama, Sunima; Chen, Lizhou; Hu, Xinyu; Wang, Song; Chen, Taolin; Shi, Yan; Huang, Xiaoqi; Gong, Qiyong

    2017-01-01

    Male and female show significant differences in important behavioral features such as shyness, yet the neural substrates of these differences remain poorly understood. Previous neuroimaging studies have demonstrated that both shyness and social anxiety in healthy subjects are associated with increased activation in the fronto-limbic and cognitive control areas. However, it remains unknown whether these brain abnormalities would be shared by different genders. Therefore, in the current study, we used resting-state fMRI (r-fMRI) to investigate sex differences in intrinsic cerebral activity that may contribute to shyness and social anxiety. Sixty subjects (28 males, 32 females) participated in r-fMRI scans, and the amplitude of low-frequency fluctuations (ALFF) and fractional ALFF (fALFF) were used to measure the spontaneous regional cerebral activity in all subjects. We first compared the differences between male and female both in the ALFF and fALFF and then we also examined the whole brain correlation between the ALFF/fALFF and the severity of shyness as well as social anxiety by genders. Referring to shyness measure, we found a significant positive correlation between shyness scores (CBSS) and ALFF/fALFF value in the frontoparietal control network and a negative correlation in the cingulo-insular network in female; while in male, there is no such correlation. For the social anxiety level, we found positive correlations between Leibowitz Social Anxiety Scale (LSAS) scores and spontaneous activity in the frontal-limbic network in male and negative correlation between the frontal-parietal network; however, such correlation was not prominent in female. This pattern suggests that shy female individuals engaged a proactive control process, driven by a positive association with activity in frontoparietal network and negative association in cingulo-insular network, whereas social anxiety males relied more on a reactive control process, driven by a positive correlation of

  7. Influence of intrinsic sympathomimetic activity and cardioselectivity on beta adrenoceptor blockade.

    Science.gov (United States)

    McDevitt, D G; Brown, H C; Carruthers, S G; Shanks, R G

    1977-05-01

    Dose-response curves for propranolol and oxprenolol were studied in healthy volunteers, with a standardized excercise test and percentage reduction in excercise heart rate (EHR) as the index of drug effect. The dose-response curves obtained were compared with similar curves previously reported for sotalol, practolol, and atenolol with identical experimental methods. Two distinct types of response were identified: in the first, shown by propranolol and sotalol, increasing doses of the beta adrenoceptor-blocking drug continued to produce increasing effects to the limits of the dose levels examined; with the second (oxprenolol and practolol), increasing the dose initially resulted in substantial increase in effect but subsequently larger doses produced almost no increase in effect. Consideration of the additional properties of these beta adrenoceptor-blocking drugs revealed that both practolol and oxprenolol have intrinsic sympathomimetric activity (ISA), whereas propranolol and sotalol do not. In addition, practolol is cardioselective. Further investigation of the possible influence of ISA or cardioselectivity on beta adrenoceptor-blocking activity was undertaken by studying the effects of combinations of drugs on EHR. Sotalol produced greater effect when given 2 hr after sotalol, oxprenolol, practolol, or atenolol. When oxprenolol was given after sotalol or oxprenolol, or practolol was given after sotalol or practolol, there was no further increase in percentage reduction in EHR. When atenolol was given, the combinations of sotalol and atenolol together with two doses either of sotalol or atenolol all induced increases and similar final percentage reductions in EHR. Thus atenolol induces effects like those of sotalol, which are quite different from those of oxprenolol or practolol. The presence or absence of ISA would appear to be the important difference between these two groups of drugs: ISA would, therefore, appear to be demonstrated in man by flattening of the

  8. Intrinsic conductances actively shape excitatory and inhibitory postsynaptic responses in olfactory bulb external tufted cells.

    Science.gov (United States)

    Liu, Shaolin; Shipley, Michael T

    2008-10-08

    The initial synapse in the olfactory system is from olfactory nerve (ON) terminals to postsynaptic targets in olfactory bulb glomeruli. Recent studies have disclosed multiple presynaptic factors that regulate this important linkage, but less is known about the contribution of postsynaptic intrinsic conductances to integration at these synapses. The present study demonstrates voltage-dependent amplification of EPSPs in external tufted (ET) cells in response to monosynaptic (ON) inputs. This amplification is mainly exerted by persistent Na(+) conductance. Larger EPSPs, which bring the membrane potential to a relatively depolarized level, are further boosted by the low-voltage-activated Ca(2+) conductance. In contrast, the hyperpolarization-activated nonselective cation conductance (I(h)) attenuates EPSPs mainly by reducing EPSP duration; this also reduces temporal summation of multiple EPSPs. Regulation of EPSPs by these subthreshold, voltage-dependent conductances can enhance both the signal-to-noise ratio and the temporal summation of multiple synaptic inputs and thus help ET cells differentiate high- and low-frequency synaptic inputs. I(h) can also transform inhibitory inputs to postsynaptic excitation. When the ET cell membrane potential is relatively depolarized, as during a burst of action potentials, IPSPs produce classic inhibition. However, near resting membrane potentials where I(h) is engaged, IPSPs produce rebound bursts of action potentials. ET cells excite GABAergic PG cells. Thus, the transformation of inhibitory inputs to postsynaptic excitation in ET cells may enhance intraglomerular inhibition of mitral/tufted cells, the main output neurons in the olfactory bulb, and hence shape signaling to olfactory cortex.

  9. Overexpression of the transcription factor Sp1 activates the OAS-RNAse L-RIG-I pathway.

    Directory of Open Access Journals (Sweden)

    Valéryane Dupuis-Maurin

    Full Text Available Deregulated expression of oncogenes or transcription factors such as specificity protein 1 (Sp1 is observed in many human cancers and plays a role in tumor maintenance. Paradoxically in untransformed cells, Sp1 overexpression induces late apoptosis but the early intrinsic response is poorly characterized. In the present work, we studied increased Sp1 level consequences in untransformed cells and showed that it turns on an early innate immune transcriptome. Sp1 overexpression does not activate known cellular stress pathways such as DNA damage response or endoplasmic reticulum stress, but induces the activation of the OAS-RNase L pathway and the generation of small self-RNAs, leading to the upregulation of genes of the antiviral RIG-I pathway at the transcriptional and translational levels. Finally, Sp1-induced intrinsic innate immune response leads to the production of the chemokine CXCL4 and to the recruitment of inflammatory cells in vitro and in vivo. Altogether our results showed that increased Sp1 level in untransformed cells constitutes a novel danger signal sensed by the OAS-RNase L axis leading to the activation of the RIG-I pathway. These results suggested that the OAS-RNase L-RIG-I pathway may be activated in sterile condition in absence of pathogen.

  10. TRAIL-Induced Caspase Activation Is a Prerequisite for Activation of the Endoplasmic Reticulum Stress-Induced Signal Transduction Pathways.

    Science.gov (United States)

    Lee, Dae-Hee; Sung, Ki Sa; Guo, Zong Sheng; Kwon, William Taehyung; Bartlett, David L; Oh, Sang Cheul; Kwon, Yong Tae; Lee, Yong J

    2016-05-01

    It is well known that tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis can be initially triggered by surface death receptors (the extrinsic pathway) and subsequently amplified through mitochondrial dysfunction (the intrinsic pathway). However, little is known about signaling pathways activated by the TRAIL-induced endoplasmic reticulum (ER) stress response. In this study, we report that TRAIL-induced apoptosis is associated with the endoplasmic reticulum (ER) stress response. Human colorectal carcinoma HCT116 cells were treated with TRAIL and the ER stress-induced signal transduction pathway was investigated. During TRAIL treatment, expression of ER stress marker genes, in particular the BiP (binding immunoglobulin protein) gene, was increased and activation of the PERK (PKR-like ER kinase)-eIF2α (eukaryotic initiation factor 2α)-ATF4 (activating transcription factor 4)-CHOP (CCAAT-enhancer-binding protein homologous protein) apoptotic signal transduction pathway occurred. Experimental data from use of a siRNA (small interfering RNA) technique, caspase inhibitor, and caspase-3-deficient cell line revealed that TRAIL-induced caspase activation is a prerequisite for the TRAIL-induced ER stress response. TRAIL-induced ER stress was triggered by caspase-8-mediated cleavage of BAP31 (B cell receptor-associated protein 31). The involvement of the proapoptotic PERK-CHOP pathway in TRAIL-induced apoptosis was verified by using a PERK knockout (PERK(-/-)) mouse embryo fibroblast (MEF) cell line and a CHOP(-/-) MEF cell line. These results suggest that TRAIL-induced the activation of ER stress response plays a role in TRAIL-induced apoptotic death.

  11. Long non-coding RNA ANRIL is up-regulated in bladder cancer and regulates bladder cancer cell proliferation and apoptosis through the intrinsic pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Hongxue [Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Department of Urology, Hospital of Xinjiang Production and Construction Corps, Urumqi 830002 (China); Li, Xuechao; Song, Yarong; Zhang, Peng; Xiao, Yajun [Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Xing, Yifei, E-mail: yifei_xing@163.com [Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2015-11-13

    Antisense non-coding RNA in the INK4 locus (ANRIL) is a member of long non-coding RNAs and has been reported to be dysregulated in several human cancers. However, the role of ANRIL in bladder cancer remains unclear. This present study aimed to investigate whether and how ANRIL involved in bladder cancer. Our results showed up-regulation of ANRIL in bladder cancer tissues versus the corresponding adjacent non-tumor tissues. To explore the specific mechanisms, ANRIL was silenced by small interfering RNA or short hairpin RNA transfection in human bladder cancer T24 and EJ cells. Knockdown of ANRIL repressed cell proliferation and increased cell apoptosis, along with decreased expression of Bcl-2 and increased expressions of Bax, cytoplasmic cytochrome c and Smac and cleaved caspase-9, caspase-3 and PARP. However, no change of cleaved caspase-8 level was observed. Furthermore, in vivo experiment confirmed that knockdown of ANRIL inhibited tumorigenic ability of EJ cells in nude mice. Meanwhile, in accordance with in vitro study, knockdown of ANRIL inhibited expression of Bcl-2 and up-regulated expressions of Bax and cleaved caspase-9, but did not affect cleaved caspase-8 level. In conclusion, we first report that ANRIL possibly serves as an oncogene in bladder cancer and regulates bladder cancer cell proliferation and apoptosis through the intrinsic apoptosis pathway. - Highlights: • We first report the role of ANRIL in bladder cancer. • ANRIL is obviously up-regulated in bladder cancer tissues. • ANRIL regulates bladder cancer cell proliferation and cell apoptosis through the intrinsic pathway.

  12. Modulation of intrinsic brain activity by electroconvulsive therapy in major depression

    Science.gov (United States)

    Leaver, Amber M.; Espinoza, Randall; Pirnia, Tara; Joshi, Shantanu H.; Woods, Roger P.; Narr, Katherine L.

    2015-01-01

    Introduction One of the most effective interventions for intractable major depressive episodes is electroconvulsive therapy (ECT). Because ECT is also relatively fast-acting, longitudinal study of its neurobiological effects offers critical insight into the mechanisms underlying depression and antidepressant response. Here we assessed modulation of intrinsic brain activity in corticolimbic networks associated with ECT and clinical response. Methods We measured resting-state functional connectivity (RSFC) in patients with treatment-resistant depression (n=30), using functional magnetic resonance imaging (fMRI) acquired before and after completing a treatment series with right-unilateral ECT. Using independent component analysis, we assessed changes in RSFC with 1) symptom improvement and 2) ECT regardless of treatment outcome in patients, with reference to healthy controls (n=33, also scanned twice). Results After ECT, consistent changes in RSFC within targeted depression-relevant functional networks were observed in the dorsal anterior cingulate (ACC), mediodorsal thalamus (mdTh), hippocampus, and right anterior temporal, medial parietal, and posterior cingulate cortex in all patients. In a separate analysis, changes in depressive symptoms were associated with RSFC changes in the dorsal ACC, mdTh, putamen, medial prefrontal, and lateral parietal cortex. RSFC of these regions did not change in healthy controls. Conclusions Neuroplasticity underlying clinical change was in part separable from changes associated with the effects of ECT observed in all patients. However, both ECT and clinical change were associated with RSFC modulation in dorsal ACC, mdTh and hippocampus, which may indicate that these regions underlie the mechanisms of clinical outcome in ECT and may be effective targets for future neurostimulation therapies. PMID:26878070

  13. Specific activation of the paralemniscal pathway during nociception.

    Science.gov (United States)

    Frangeul, Laura; Porrero, Cesar; Garcia-Amado, Maria; Maimone, Benedetta; Maniglier, Madlyne; Clascá, Francisco; Jabaudon, Denis

    2014-05-01

    Two main neuronal pathways connect facial whiskers to the somatosensory cortex in rodents: (i) the lemniscal pathway, which originates in the brainstem principal trigeminal nucleus and is relayed in the ventroposterior thalamic nucleus and (ii) the paralemniscal pathway, originating in the spinal trigeminal nucleus and relayed in the posterior thalamic nucleus. While lemniscal neurons are readily activated by whisker contacts, the contribution of paralemniscal neurons to perception is less clear. Here, we functionally investigated these pathways by manipulating input from the whisker pad in freely moving mice. We report that while lemniscal neurons readily respond to neonatal infraorbital nerve sectioning or whisker contacts in vivo, paralemniscal neurons do not detectably respond to these environmental changes. However, the paralemniscal pathway is specifically activated upon noxious stimulation of the whisker pad. These findings reveal a nociceptive function for paralemniscal neurons in vivo that may critically inform context-specific behaviour during environmental exploration.

  14. ARRHYTHMIA INDUCED BY NICOTINE ACTIVATING CARDIAC INTRINSIC NEURONS IN CANINE ATRIAL AND VENTRICULAR GANGLIAL PLEXUS

    Institute of Scientific and Technical Information of China (English)

    袁秉祥; 刘书勤; 李萍; 李新华

    2002-01-01

    Objective To study the arrhythmia induced by stimulation of nicotine-sensitive neurons in cardiac ganglial plexuses. Methods When nicotine (100μg) was injected into canine right atrial ganglial plexus (RAGP) and ganglial plexus between aorta and pulmonary artery (A-PGP) in 33 anesthetized open-chest dog, electrocardiogram, atrial force and ventricular intramyocardial pressures (IMP) were recorded. The responses were also recorded following administration of atropine or propranolol and after heart acute decentralization. Results Ventricular arrhythmia (VA) was induced by injections of nicotine into A-PGP, but not by injections of nicotine into RAGP in 13 dogs. Atrioventricilar (A-V) block was induced by nicotine activating RAGP in 10 dogs, but not by nicotine activating A-PGP. Propranolol could reduce the frequency of VA elicited by stimulating A-PGP, atropine could reduce the frequency of A-V block elicited by stimulating RAGP. After acute decentralization, VA was still induced by activation of A-PGP in 9 dogs, but A-V block elicited by stimulating RAGP was decreased. Conclusion VA is induced by stimulating N receptor in cardiac nicotine-sensitive efferent sympathetic neurons of ventricular ganglial plexus (A-PGP), and then modifying β receptor of ventricles. A-V block is elicited by stimulating N receptor in atrial ganglial plexus (RAGP), then modifying M receptor of A-V node not only via efferent parasympathetic neurons, but also via afferent pathway.

  15. The transcriptional repressor Bcl6 controls the stability of regulatory T cells by intrinsic and extrinsic pathways

    Science.gov (United States)

    Sawant, Deepali V; Wu, Hao; Yao, Weiguo; Sehra, Sarita; Kaplan, Mark H; Dent, Alexander L

    2015-01-01

    Foxp3+ regulatory T (Treg) cells are essential to maintain immune homeostasis, yet controversy exists about the stability of this cell population. Bcl6-deficient (Bcl6−/−) mice develop severe and spontaneous T helper type 2 (Th2) inflammation and Bcl6-deficient Treg cells are ineffective at controlling Th2 responses. We used a lineage tracing approach to analyse the fate of Treg cells in these mice. In the periphery of Bcl6−/− mice, increased numbers of Foxp3-negative ‘exTreg’ cells were found, particularly in the CD25+ population. ExTreg cells from Bcl6−/− mice expressed increased interleukin-17 (IL-17) and extremely elevated levels of Th2 cytokines compared with wild-type exTreg cells. Although Treg cells normally express only low levels of cytokines, Treg cells from Bcl6−/− mice secreted higher levels of IL-4, IL-5, IL-13 and IL-17 than wild-type conventional T cells. Next, Treg-specific conditional Bcl6-deficient (Bcl6Foxp3−/−) mice were analysed. Bcl6Foxp3−/− mice do not develop inflammatory disease, indicating a requirement for non-Treg cells for inflammation in Bcl6−/− mice, and have normal numbers of exTreg cells. We induced Th2-type allergic airway inflammation in Bcl6Foxp3−/− mice, and found that while exTreg cytokine expression was normal, Bcl6-deficient Treg cells expressed higher levels of the Th2-specific regulator Gata3 than Bcl6+ Treg cells. Bcl6Foxp3−/− mice had increased numbers of Th2 cells after induction of airway inflammation and increased T cells in the bronchoalveolar lavage fluid. These data show both Treg-intrinsic and Treg-extrinsic roles for Bcl6 in controlling Treg cell stability and Th2 inflammation, and support the idea that Bcl6 expression in Treg cells is critical for controlling Th2 responses. PMID:25262912

  16. Sertraline, an antidepressant, induces apoptosis in hepatic cells through the mitogen-activated protein kinase pathway.

    Science.gov (United States)

    Chen, Si; Xuan, Jiekun; Wan, Liqing; Lin, Haixia; Couch, Letha; Mei, Nan; Dobrovolsky, Vasily N; Guo, Lei

    2014-02-01

    Sertraline is generally used for the treatment of depression and is also approved for the treatment of panic, obsessive-compulsive, and posttraumatic stress disorders. Previously, using rat primary hepatocytes and isolated mitochondria, we demonstrated that sertraline caused hepatic cytotoxicity and mitochondrial impairment. In the current study, we investigated and characterized molecular mechanisms of sertraline toxicity in human hepatoma HepG2 cells. Sertraline decreased cell viability and induced apoptosis in a dose- and time-dependent manner. Sertraline activated the intrinsic checkpoint protein caspase-9 and caused the release of cytochrome c from mitochondria to cytosol; this process was Bcl-2 family dependent because antiapoptotic Bcl-2 family proteins were decreased. Pretreatment of the HepG2 cells with caspase-3, caspase-8, and caspase-9 inhibitors partially but significantly reduced the release of lactate dehydrogenase, indicating that sertraline-induced apoptosis is mediated by both intrinsic and extrinsic apoptotic pathways. Moreover, sertraline markedly increased the expression of tumor necrosis factor (TNF) and the phosphorylation of JNK, extracellular signal-regulated kinase (ERK1/2), and p38. In sertraline-treated cells, the induction of apoptosis and cell death was shown to be the result of activation of JNK, but not ERK1/2 or p38 in the mitogen-activated protein kinase (MAPK) pathway. Furthermore, silencing MAP4K4, the upstream kinase of JNK, attenuated both apoptosis and cell death caused by sertraline. Taken together, our findings suggest that sertraline induced apoptosis in HepG2 cells at least partially via activation of the TNF-MAP4K4-JNK cascade signaling pathway.

  17. Altered of apoptotic markers of both extrinsic and intrinsic pathways induced by hepatitis C virus infection in peripheral blood mononuclear cells

    Directory of Open Access Journals (Sweden)

    Albertoni Guilherme

    2012-12-01

    Full Text Available Abstract Background Chronic hepatitis C (CHC has emerged as a leading cause of cirrhosis in the U.S. and across the world. To understand the role of apoptotic pathways in hepatitis C virus (HCV infection, we studied the mRNA and protein expression patterns of apoptosis-related genes in peripheral blood mononuclear cells (PBMC obtained from patients with HCV infection. Methods The present study included 50 subjects which plasma samples were positive for HCV, but negative for human immunodeficiency virus (HIV or hepatitis B virus (HBV. These cases were divided into four groups according to METAVIR, a score-based analysis which helps to interpret a liver biopsy according to the degree of inflammation and fibrosis. mRNA expression of the studied genes were analyzed by reverse transcription of quantitative polymerase chain reaction (RT-qPCR and protein levels, analyzed by ELISA, was also conducted. HCV genotyping was also determined. Results HCV infection increased mRNA expression and protein synthesis of caspase 8 in group 1 by 3 fold and 4 fold, respectively (p group 4 HCV infection increased mRNA expression and protein synthesis of caspase 9 by 2 fold and 1,5 fold, respectively (p group 1 by 4 fold and 5 fold, respectively, and in group 4 by 6 fold and 7 fold, respectively (p Conclusions HCV induces alteration at both genomic and protein levels of apoptosis markers involved with extrinsic and intrinsic pathways.

  18. Mitogen Activated Protein kinase signal transduction pathways in the prostate

    Directory of Open Access Journals (Sweden)

    Koul Sweaty

    2004-06-01

    Full Text Available Abstract The biochemistry of the mitogen activated protein kinases ERK, JNK, and p38 have been studied in prostate physiology in an attempt to elucidate novel mechanisms and pathways for the treatment of prostatic disease. We reviewed articles examining mitogen-activated protein kinases using prostate tissue or cell lines. As with other tissue types, these signaling modules are links/transmitters for important pathways in prostate cells that can result in cellular survival or apoptosis. While the activation of the ERK pathway appears to primarily result in survival, the roles of JNK and p38 are less clear. Manipulation of these pathways could have important implications for the treatment of prostate cancer and benign prostatic hypertrophy.

  19. An enzymatic atavist revealed in dual pathways for water activation.

    Directory of Open Access Journals (Sweden)

    Donghong Min

    2008-08-01

    Full Text Available Inosine monophosphate dehydrogenase (IMPDH catalyzes an essential step in the biosynthesis of guanine nucleotides. This reaction involves two different chemical transformations, an NAD-linked redox reaction and a hydrolase reaction, that utilize mutually exclusive protein conformations with distinct catalytic residues. How did Nature construct such a complicated catalyst? Here we employ a "Wang-Landau" metadynamics algorithm in hybrid quantum mechanical/molecular mechanical (QM/MM simulations to investigate the mechanism of the hydrolase reaction. These simulations show that the lowest energy pathway utilizes Arg418 as the base that activates water, in remarkable agreement with previous experiments. Surprisingly, the simulations also reveal a second pathway for water activation involving a proton relay from Thr321 to Glu431. The energy barrier for the Thr321 pathway is similar to the barrier observed experimentally when Arg418 is removed by mutation. The Thr321 pathway dominates at low pH when Arg418 is protonated, which predicts that the substitution of Glu431 with Gln will shift the pH-rate profile to the right. This prediction is confirmed in subsequent experiments. Phylogenetic analysis suggests that the Thr321 pathway was present in the ancestral enzyme, but was lost when the eukaryotic lineage diverged. We propose that the primordial IMPDH utilized the Thr321 pathway exclusively, and that this mechanism became obsolete when the more sophisticated catalytic machinery of the Arg418 pathway was installed. Thus, our simulations provide an unanticipated window into the evolution of a complex enzyme.

  20. Activation of the NOTCH pathway in head and neck cancer.

    Science.gov (United States)

    Sun, Wenyue; Gaykalova, Daria A; Ochs, Michael F; Mambo, Elizabeth; Arnaoutakis, Demetri; Liu, Yan; Loyo, Myriam; Agrawal, Nishant; Howard, Jason; Li, Ryan; Ahn, Sun; Fertig, Elana; Sidransky, David; Houghton, Jeffery; Buddavarapu, Kalyan; Sanford, Tiffany; Choudhary, Ashish; Darden, Will; Adai, Alex; Latham, Gary; Bishop, Justin; Sharma, Rajni; Westra, William H; Hennessey, Patrick; Chung, Christine H; Califano, Joseph A

    2014-02-15

    NOTCH1 mutations have been reported to occur in 10% to 15% of head and neck squamous cell carcinomas (HNSCC). To determine the significance of these mutations, we embarked upon a comprehensive study of NOTCH signaling in a cohort of 44 HNSCC tumors and 25 normal mucosal samples through a set of expression, copy number, methylation, and mutation analyses. Copy number increases were identified in NOTCH pathway genes, including the NOTCH ligand JAG1. Gene set analysis defined a differential expression of the NOTCH signaling pathway in HNSCC relative to normal tissues. Analysis of individual pathway-related genes revealed overexpression of ligands JAG1 and JAG2 and receptor NOTCH3. In 32% of the HNSCC examined, activation of the downstream NOTCH effectors HES1/HEY1 was documented. Notably, exomic sequencing identified 5 novel inactivating NOTCH1 mutations in 4 of the 37 tumors analyzed, with none of these tumors exhibiting HES1/HEY1 overexpression. Our results revealed a bimodal pattern of NOTCH pathway alterations in HNSCC, with a smaller subset exhibiting inactivating NOTCH1 receptor mutations but a larger subset exhibiting other NOTCH1 pathway alterations, including increases in expression or gene copy number of the receptor or ligands as well as downstream pathway activation. Our results imply that therapies that target the NOTCH pathway may be more widely suitable for HNSCC treatment than appreciated currently.

  1. Ligand-induced evolution of intrinsic fluorescence and catalytic activity from cobalt ferrite nanoparticles.

    Science.gov (United States)

    Pal, Monalisa; Kundu, Anirban; Rakshit, Rupali; Mandal, Kalyan

    2015-06-08

    To develop CoFe(2)O(4) as magneto-fluorescent nanoparticles (NPs) for biomedical applications, it would be advantageous to identify any intrinsic fluorescence of this important magnetic material by simply adjusting the surface chemistry of the NPs themselves. Herein, we demonstrate that intrinsic multicolor fluorescence, covering the whole visible region, can be induced by facile functionalization of CoFe(2)O(4) NPs with Na-tartrate. Moreover, the functionalized CoFe(2)O(4) NPs also show unprecedented catalytic efficiency in the degradation of both biologically and environmentally harmful dyes, pioneering the potential application of these NPs in therapeutics and wastewater treatment. Detailed investigation through various spectroscopic tools unveils the story behind the emergence of this unique optical property of CoFe(2)O(4) NPs upon functionalization with tartrate ligands. We believe our developed multifunctional CoFe(2)O(4) NPs hold great promise for advanced biomedical and technological applications.

  2. Combination phenylbutyrate/gemcitabine therapy effectively inhibits in vitro and in vivo growth of NSCLC by intrinsic apoptotic pathways

    Directory of Open Access Journals (Sweden)

    Schniewind Bodo

    2006-11-01

    Full Text Available Abstract Background Standard chemotherapy protocols in NSCLC are of limited clinical benefit. Histone deacetylase (HDAC inhibitors represent a new strategy in human cancer therapy. In this study the combination of the HDAC inhibitor phenylbutyrate (PB and the nucleoside analogue gemcitabine (GEM was evaluated and the mechanisms underlying increased cell death were analyzed. Methods Dose escalation studies evaluating the cytotoxicity of PB (0.01–100 mM, GEM (0.01–100 μg/ml and a combination of the two were performed on two NSCLC cell lines (BEN and KNS62. Apoptotic cell death was quantified. The involvement of caspase-dependent cell death and MAP-kinase activation was analyzed. Additionally, mitochondrial damage was determined. In an orthotopic animal model the combined effect of PB and GEM on therapy was analyzed. Results Applied as a single drug both GEM and PB revealed limited potential to induce apoptosis in KNS62 and Ben cells. Combination therapy was 50–80% (p = 0.012 more effective than either agent alone. On the caspase level, combination therapy significantly increased cleavage of the pro-forms compared to single chemotherapy. The broad spectrum caspase-inhibitor zVAD was able to inhibit caspase cleavage completely, but reduced the frequency of apoptotic cells only by 30%. Combination therapy significantly increased changes in MTP and the release of cyto-c, AIF and Smac/Diabolo into the cytoplasm. Furthermore, the inhibitors of apoptosis c-IAP1 and c-IAP2 were downregulated and it was shown that in combination therapy JNK activation contributed significantly to induction of apoptosis. The size of the primary tumors growing orthotopically in SCID mice treated for 4 weeks with GEM and PB was significantly reduced (2.2–2.7 fold compared to GEM therapy alone. The Ki-67 (KNS62: p = 0.015; Ben: p = 0.093 and topoisomerase IIα (KNS62: p = 0.008; Ben: p = 0.064 proliferation indices were clearly reduced in tumors treated by combination

  3. Involvement of ER stress and activation of apoptotic pathways in fisetin induced cytotoxicity in human melanoma.

    Science.gov (United States)

    Syed, Deeba N; Lall, Rahul K; Chamcheu, Jean Christopher; Haidar, Omar; Mukhtar, Hasan

    2014-12-01

    The prognosis of malignant melanoma remains poor in spite of recent advances in therapeutic strategies for the deadly disease. Fisetin, a dietary flavonoid is currently being investigated for its growth inhibitory properties in various cancer models. We previously showed that fisetin inhibited melanoma growth in vitro and in vivo. Here, we evaluated the molecular basis of fisetin induced cytotoxicity in metastatic human melanoma cells. Fisetin treatment induced endoplasmic reticulum (ER) stress in highly aggressive A375 and 451Lu human melanoma cells, as revealed by up-regulation of ER stress markers including IRE1α, XBP1s, ATF4 and GRP78. Time course analysis indicated that the ER stress was associated with activation of the extrinsic and intrinsic apoptotic pathways. Fisetin treated 2-D melanoma cultures displayed autophagic response concomitant with induction of apoptosis. Prolonged treatment (16days) with fisetin in a 3-D reconstituted melanoma model resulted in inhibition of melanoma progression with significant apoptosis, as evidenced by increased staining of cleaved Caspase-3 in the treated constructs. However, no difference in the expression of autophagic marker LC-3 was noted between treated and control groups. Fisetin treatment to 2-D melanoma cultures resulted in phosphorylation and activation of the multifunctional AMP-activated protein kinase (AMPK) involved in the regulation of diverse cellular processes, including autophagy and apoptosis. Silencing of AMPK failed to prevent cell death indicating that fisetin induced cytotoxicity is mediated through both AMPK-dependent and -independent mechanisms. Taken together, our studies confirm apoptosis as the primary mechanism through which fisetin inhibits melanoma cell growth and that activation of both extrinsic and intrinsic pathways contributes to fisetin induced cytotoxicity.

  4. Therapeutic targeting of EGFR-activated metabolic pathways in glioblastoma.

    Science.gov (United States)

    Gao, Qinglei; Lei, Ting; Ye, Fei

    2013-08-01

    The highly divergent histological heterogeneities, aggressive invasion and extremely poor response to treatment make glioblastoma (GBM) one of the most lethal and difficult cancers in humans. Among key elements driving its behavior is epidermal growth factor receptor (EGFR), however, neither traditional therapy including neurosurgery, radiation, temozolomide, nor targeted EGFR therapeutics in clinic has generated promising results to date. Strategies are now focusing on blocking the downstream EGFR-activated metabolic pathways and the key phosphorylated kinases. Here, we review two major EGFR-activated downstream metabolic pathways including the PI3K/AKT/mTOR and RAS/RAF/MAPK pathways and their key phosphorylated kinase alterations in GBMs. This review also discusses potential pharmacological progress from bench work to clinical trials in order to evaluate specific inhibitors as well as therapeutics targeting PI3K and RAS signaling pathways. Several factors impede clinical progress in targeting GBM, including the high rates of acquired resistance, heterogeneity within and across the tumors, complexity of signaling pathways and difficulty in traversing the blood-brain barrier (BBB). Substantial insight into genetic and molecular pathways and strategies to better tap the potential of these agents include rational combinatorial regimens and molecular phenotype-based patient enrichment, each of which will undoubtedly generate new therapeutic approaches to combat these devastating disabilities in the near future.

  5. Intrinsic Kinetics of Dimethyl Ether Synthesis from Plasma Activation of CO2 Hydrogenation over Cu-Fe-Ce/HZSM-5.

    Science.gov (United States)

    Su, Tongming; Zhou, Xinhui; Qin, Zuzeng; Ji, Hongbing

    2017-02-02

    CO2 is activated in a plasma reactor followed by hydrogenation over a Cu-Fe-Ce/HZSM-5 catalyst, and the intrinsic kinetics of the plasma catalytic process are studied. Compared with CO2 hydrogenation using Cu-Fe-Ce/HZSM-5 alone, the CO2 conversion and the dimethyl ether selectivity for the plasma catalytic process are increased by 16.3 %, and 10.1 %, respectively, indicating that the CO2 was activated by the plasma to promote hydrogenation. A study of the intrinsic kinetics shows that the activation energies of methanol formation, the reverse water-gas shift reaction, and methanol dehydration to dimethyl ether are 149.34, 75.47, and 73.18 kJ mol(-1) , respectively, which are lower than if Cu-Fe-Ce/HZSM-5 is used without plasma, indicating that the activation of CO2 in the plasma reduces the activation energy of the hydrogenation reaction and improves the yield of dimethyl ether.

  6. Wnt Pathway Activation in Long Term Remnant Rat Model

    Directory of Open Access Journals (Sweden)

    E. Banon-Maneus

    2014-01-01

    Full Text Available Progression of chronic kidney disease (CKD is characterized by deposition of extracellular matrix. This is an irreversible process that leads to tubulointerstitial fibrosis and finally loss of kidney function. Wnt/β-catenin pathway was reported to be aberrantly activated in the progressive damage associated with chronic organ failure. Extensive renal ablation is an experimental model widely used to gain insight into the mechanisms responsible for the development of CKD, but it was not evaluated for Wnt/β-catenin pathway. This study aimed to elucidate if the rat 5/6 renal mass reduction model (RMR is a good model for the Wnt/β-catenin activation and possible next modulation. RMR model was evaluated at 12 and 18 weeks after the surgery, when CKD is close to end-stage kidney disease demonstrated by molecular and histological studies. Wnt pathway components were analyzed at mRNA and protein level. Our results demonstrate that Wnt pathway is active by increase of β-catenin at mRNA level and nuclear translocation in tubular epithelium as well as some target genes. These results validate the RMR model for future modulation of Wnt pathway, starting at shorter time after the surgery.

  7. Synergistic inhibition of the intrinsic factor X activation by protein S and C4b-binding protein

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    The complement protein C4b-binding protein plays an important role in the regulation of the protein C anticoagulant pathway. C4b-binding protein can bind to protein S, thereby inhibiting the cofactor activity of protein S for activated protein C. In this report, we describe a new role for

  8. Synergistic inhibition of the intrinsic factor X activation by protein S and C4b-binding protein

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    The complement protein C4b-binding protein plays an important role in the regulation of the protein C anticoagulant pathway. C4b-binding protein can bind to protein S, thereby inhibiting the cofactor activity of protein S for activated protein C. In this report, we describe a new role for C4b-bindin

  9. An Interferon Regulated MicroRNA Provides Broad Cell-Intrinsic Antiviral Immunity through Multihit Host-Directed Targeting of the Sterol Pathway.

    Science.gov (United States)

    Robertson, Kevin A; Hsieh, Wei Yuan; Forster, Thorsten; Blanc, Mathieu; Lu, Hongjin; Crick, Peter J; Yutuc, Eylan; Watterson, Steven; Martin, Kimberly; Griffiths, Samantha J; Enright, Anton J; Yamamoto, Mami; Pradeepa, Madapura M; Lennox, Kimberly A; Behlke, Mark A; Talbot, Simon; Haas, Jürgen; Dölken, Lars; Griffiths, William J; Wang, Yuqin; Angulo, Ana; Ghazal, Peter

    2016-03-01

    In invertebrates, small interfering RNAs are at the vanguard of cell-autonomous antiviral immunity. In contrast, antiviral mechanisms initiated by interferon (IFN) signaling predominate in mammals. Whilst mammalian IFN-induced miRNA are known to inhibit specific viruses, it is not known whether host-directed microRNAs, downstream of IFN-signaling, have a role in mediating broad antiviral resistance. By performing an integrative, systematic, global analysis of RNA turnover utilizing 4-thiouridine labeling of newly transcribed RNA and pri/pre-miRNA in IFN-activated macrophages, we identify a new post-transcriptional viral defense mechanism mediated by miR-342-5p. On the basis of ChIP and site-directed promoter mutagenesis experiments, we find the synthesis of miR-342-5p is coupled to the antiviral IFN response via the IFN-induced transcription factor, IRF1. Strikingly, we find miR-342-5p targets mevalonate-sterol biosynthesis using a multihit mechanism suppressing the pathway at different functional levels: transcriptionally via SREBF2, post-transcriptionally via miR-33, and enzymatically via IDI1 and SC4MOL. Mass spectrometry-based lipidomics and enzymatic assays demonstrate the targeting mechanisms reduce intermediate sterol pathway metabolites and total cholesterol in macrophages. These results reveal a previously unrecognized mechanism by which IFN regulates the sterol pathway. The sterol pathway is known to be an integral part of the macrophage IFN antiviral response, and we show that miR-342-5p exerts broad antiviral effects against multiple, unrelated pathogenic viruses such Cytomegalovirus and Influenza A (H1N1). Metabolic rescue experiments confirm the specificity of these effects and demonstrate that unrelated viruses have differential mevalonate and sterol pathway requirements for their replication. This study, therefore, advances the general concept of broad antiviral defense through multihit targeting of a single host pathway.

  10. Increased Intrinsic Activity of Medial-Temporal Lobe Subregions is Associated with Decreased Cortical Thickness of Medial-Parietal Areas in Patients with Alzheimer's Disease Dementia.

    Science.gov (United States)

    Pasquini, Lorenzo; Scherr, Martin; Tahmasian, Masoud; Myers, Nicholas E; Ortner, Marion; Kurz, Alexander; Förstl, Hans; Zimmer, Claus; Grimmer, Timo; Akhrif, Atae; Wohlschläger, Afra M; Riedl, Valentin; Sorg, Christian

    2016-01-01

    In Alzheimer's disease (AD), disrupted connectivity between medial-parietal cortices and medial-temporal lobes (MTL) is linked with increased MTL local functional connectivity, and parietal atrophy is associated with increased MTL memory activation. We hypothesized that intrinsic activity in MTL subregions is increased and associated with medial-parietal degeneration and impaired memory in AD. To test this hypothesis, resting-state-functional and structural-MRI was assessed in 22 healthy controls, 22 mild cognitive impairment patients, and 21 AD-dementia patients. Intrinsic activity was measured by power-spectrum density of blood-oxygenation-level-dependent signal, medial-parietal degeneration by cortical thinning. In AD-dementia patients, intrinsic activity was increased for several right MTL subregions. Raised intrinsic activity in dentate gyrus and cornu ammonis 1 was associated with cortical thinning in posterior cingulate cortices, and at-trend with impaired delayed recall. Critically, increased intrinsic activity in the right entorhinal cortex was associated with ipsilateral posterior cingulate degeneration. Our results provide evidence that in AD, intrinsic activity in MTL subregions is increased and associated with medial-parietal atrophy. Results fit a model in which medial-parietal degeneration contributes to MTL dysconnectivity from medial-parietal cortices, potentially underpinning disinhibition-like changes in MTL activity.

  11. Does intrinsic motivation strengthen physical activity habit? Modeling relationships between self-determination, past behaviour, and habit strength.

    Science.gov (United States)

    Gardner, Benjamin; Lally, Phillippa

    2013-10-01

    Habit formation is thought to aid maintenance of physical activity, but little research is available into determinants of habit strength aside from repeated performance. Previous work has shown that intrinsically motivated physical activity, underpinned by inherent satisfaction derived from activity, is more likely to be sustained. We explored whether this might reflect a tendency for self-determined activity to become more strongly habitual. A sample of 192 adults aged 18-30 completed measures of motivational regulation, intention, behaviour, and habit strength. Results showed that self-determined regulation interacted with past behaviour in predicting habit strength: prior action was more predictive of habit strength among more autonomously motivated participants. There was an unexpected direct effect of self-determined regulation on habit strength, independently of past behaviour. Findings offer possible directions for future habit formation work.

  12. Enhancement of intrinsic antitumor activity in spore-endotoxin mixtures of Bacillus thuringiensis by exposure to ultraviolet radiation

    Energy Technology Data Exchange (ETDEWEB)

    Zamola, B.; Karminski-Zamola, G.; Fuks, Z.; Kubovic, M. (Zagreb Univ. (Yugoslavia)); Wrishcer, M. (Institut Rudjer Boskovic, Zagreb (Yugoslavia))

    1985-03-01

    Irradiation of spore-endotoxin mixtures from Bacillus thuringiensis cultures at 254 nm (60 ..mu..W cm/sup -2/) enhances their intrinsic antitumor potency as well as that of either component. The extent of enhancement depends on the length of exposure (optimum: 35 min) and may thus be due to photochemical changes of the endotoxin protein or/and to photoproduction of additional compounds with antitumor activity. Antitumor effects, expressed as survival rates of C57BL/6 mice inoculated with Lewis' mouse lung carcinoma and subjected to treatments 24 h later, depended on the number of doses of preparations administered (mixture, separated components).

  13. Active microrheology of Chaetopterus mucus determines three intrinsic lengthscales that govern material properties

    CERN Document Server

    Weigand, W J; Deheyn, D D; Morales-Sanz, A; Blair, D L; Urbach, J S; Robertson-Anderson, R M

    2016-01-01

    We characterize the scale-dependent rheological properties of mucus from the Chaetopterus marine worm and determine the intrinsic lengthscales controlling distinct rheological and structural regimes. Mucus produced by this ubiquitous filter feeder serves a host of roles including filtration, protection and trapping nutrients. The ease of clean mucus extraction coupled with similarities to human mucus rheology also make Chaetopterus mucus a potential model system for elucidating human mucus mechanics. We use optically trapped microsphere probes of 2-10 microns, to induce oscillatory strains and measure mucus stress response. We show that viscoelastic properties are highly dependent on the strain scale (l) with three distinct regimes emerging: microscale: l_110 microns. While mucus response is similar to water for l_1 indicating that probes rarely contact the mucus mesh, for l_2 the response is distinctly more viscous and independent of probe size, demonstrating that the mucus behaves as a continuum. However, t...

  14. Activation of the hedgehog pathway in advanced prostate cancer

    Directory of Open Access Journals (Sweden)

    McCormick Frank

    2004-10-01

    Full Text Available Abstract Background The hedgehog pathway plays a critical role in the development of prostate. However, the role of the hedgehog pathway in prostate cancer is not clear. Prostate cancer is the second most prevalent cause of cancer death in American men. Therefore, identification of novel therapeutic targets for prostate cancer has significant clinical implications. Results Here we report that activation of the hedgehog pathway occurs frequently in advanced human prostate cancer. We find that high levels of hedgehog target genes, PTCH1 and hedgehog-interacting protein (HIP, are detected in over 70% of prostate tumors with Gleason scores 8–10, but in only 22% of tumors with Gleason scores 3–6. Furthermore, four available metastatic tumors all have high expression of PTCH1 and HIP. To identify the mechanism of the hedgehog signaling activation, we examine expression of Su(Fu protein, a negative regulator of the hedgehog pathway. We find that Su(Fu protein is undetectable in 11 of 27 PTCH1 positive tumors, two of them contain somatic loss-of-function mutations of Su(Fu. Furthermore, expression of sonic hedgehog protein is detected in majority of PTCH1 positive tumors (24 out of 27. High levels of hedgehog target genes are also detected in four prostate cancer cell lines (TSU, DU145, LN-Cap and PC3. We demonstrate that inhibition of hedgehog signaling by smoothened antagonist, cyclopamine, suppresses hedgehog signaling, down-regulates cell invasiveness and induces apoptosis. In addition, cancer cells expressing Gli1 under the CMV promoter are resistant to cyclopamine-mediated apoptosis. All these data suggest a significant role of the hedgehog pathway for cellular functions of prostate cancer cells. Conclusion Our data indicate that activation of the hedgehog pathway, through loss of Su(Fu or overexpression of sonic hedgehog, may involve tumor progression and metastases of prostate cancer. Thus, targeted inhibition of hedgehog signaling may have

  15. Intrinsic Brain Activity of Cognitively Normal Older Persons Resembles More That of Patients Both with and at Risk for Alzheimer's Disease Than That of Healthy Younger Persons

    Science.gov (United States)

    Pasquini, Lorenzo; Tonch, Annika; Plant, Claudia; Zherdin, Andrew; Ortner, Marion; Kurz, Alexander; Förstl, Hans; Zimmer, Claus; Grimmer, Timo; Wohlschäger, Afra; Riedl, Valentin

    2014-01-01

    Abstract In Alzheimer's disease (AD), recent findings suggest that amyloid-β (Aβ)-pathology might start 20–30 years before first cognitive symptoms arise. To account for age as most relevant risk factor for sporadic AD, it has been hypothesized that lifespan intrinsic (i.e., ongoing) activity of hetero-modal brain areas with highest levels of functional connectivity triggers Aβ-pathology. This model induces the simple question whether in older persons without any cognitive symptoms intrinsic activity of hetero-modal areas is more similar to that of symptomatic patients with AD or to that of younger healthy persons. We hypothesize that due to advanced age and therefore potential impact of pre-clinical AD, intrinsic activity of older persons resembles more that of patients than that of younger controls. We tested this hypothesis in younger (ca. 25 years) and older healthy persons (ca. 70 years) and patients with mild cognitive impairment and AD-dementia (ca. 70 years) by the use of resting-state functional magnetic resonance imaging, distinct measures of intrinsic brain activity, and different hierarchical clustering approaches. Independently of applied methods and involved areas, healthy older persons' intrinsic brain activity was consistently more alike that of patients than that of younger controls. Our result provides evidence for larger similarity in intrinsic brain activity between healthy older persons and patients with or at-risk for AD than between older and younger ones, suggesting a significant proportion of pre-clinical AD cases in the group of cognitively normal older people. The observed link of aging and AD with intrinsic brain activity supports the view that lifespan intrinsic activity may contribute critically to the pathogenesis of AD. PMID:24689864

  16. Src kinase conformational activation: thermodynamics, pathways, and mechanisms.

    Directory of Open Access Journals (Sweden)

    Sichun Yang

    2008-03-01

    Full Text Available Tyrosine kinases of the Src-family are large allosteric enzymes that play a key role in cellular signaling. Conversion of the kinase from an inactive to an active state is accompanied by substantial structural changes. Here, we construct a coarse-grained model of the catalytic domain incorporating experimental structures for the two stable states, and simulate the dynamics of conformational transitions in kinase activation. We explore the transition energy landscapes by constructing a structural network among clusters of conformations from the simulations. From the structural network, two major ensembles of pathways for the activation are identified. In the first transition pathway, we find a coordinated switching mechanism of interactions among the alphaC helix, the activation-loop, and the beta strands in the N-lobe of the catalytic domain. In a second pathway, the conformational change is coupled to a partial unfolding of the N-lobe region of the catalytic domain. We also characterize the switching mechanism for the alphaC helix and the activation-loop in detail. Finally, we test the performance of a Markov model and its ability to account for the structural kinetics in the context of Src conformational changes. Taken together, these results provide a broad framework for understanding the main features of the conformational transition taking place upon Src activation.

  17. Activation of the mitogen-activated protein kinase pathways by heat shock

    OpenAIRE

    Dorion, Sonia; Landry, Jacques

    2002-01-01

    In addition to inducing new transcriptional activities that lead within a few hours to the accumulation of heat shock proteins (Hsps), heat shock activates within minutes the major signaling transduction pathways involving mitogen-activated protein kinases, extracellular signal–regulated kinase, stress-activated protein kinase 1 (SAPK1)–c-Jun N-terminal kinase, and SAPK2-p38. These kinases are involved in both survival and death pathways in response to other stresses and may, therefore, contr...

  18. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+). We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance.

  19. Aluminum hydroxide adjuvant differentially activates the three complement pathways with major involvement of the alternative pathway.

    Directory of Open Access Journals (Sweden)

    Esin Güven

    Full Text Available Al(OH3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH3 involves the three major pathways by monitoring complement components in Al(OH3-treated serum and in Al(OH3-containing precipitates. Al(OH3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg(2+. We thus confirm that Al(OH3 activates the complement system and show that the alternative pathway is of major importance.

  20. Aluminum Hydroxide Adjuvant Differentially Activates the Three Complement Pathways with Major Involvement of the Alternative Pathway

    Science.gov (United States)

    Güven, Esin; Duus, Karen; Laursen, Inga; Højrup, Peter; Houen, Gunnar

    2013-01-01

    Al(OH)3 is the most common adjuvant in human vaccines, but its mode of action remains poorly understood. Complement involvement in the adjuvant properties of Al(OH)3 has been suggested in several reports together with a depot effect. It is here confirmed that Al(OH)3 treatment of serum depletes complement components and activates the complement system. We show that complement activation by Al(OH)3 involves the three major pathways by monitoring complement components in Al(OH)3-treated serum and in Al(OH)3-containing precipitates. Al(OH)3 activation of complement results in deposition of C3 cleavage products and membrane attack complex (MAC) and in generation of the anaphylatoxins C3a and C5a. Complement activation was time dependent and inhibited by chelation with EDTA but not EGTA+Mg2+. We thus confirm that Al(OH)3 activates the complement system and show that the alternative pathway is of major importance. PMID:24040248

  1. Pathway data concerning differentiation and activation of macrophage - DMPD | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available DMPD Pathway data concerning differentiation and activation of macrophage Data detail Data name Pathway data... concerning differentiation and activation of macrophage Description of data contents Pathways concerning differentiation and activat...History of This Database Site Policy | Contact Us Pathway data concerning differentiation and activation of macrophage - DMPD | LSDB Archive ... ...ion of macrophage extracted from the literature list in

  2. Ongoing intrinsic synchronous activity is required for the functional maturation of CA3-CA1 glutamatergic synapses.

    Science.gov (United States)

    Huupponen, Johanna; Molchanova, Svetlana M; Lauri, Sari E; Taira, Tomi

    2013-11-01

    Fine-tuning of synaptic connectivity during development is guided by intrinsic activity of the immature networks characteristically consisting of intermittent bursts of synchronous activity. However, the role of synchronous versus asynchronous activity in synapse maturation in the brain is unclear. Here, we have pharmacologically prevented generation of synchronous activity in the immature rat CA3-CA1 circuitry in a manner that preserves unitary activity. Long-term desynchronization of the network resulted in weakening of AMPA-receptor-mediated glutamatergic transmission in CA1 pyramidal cells. This weakening was dependent on protein phosphatases and mGluR activity, associated with an increase in the proportion of silent synapses and a decrease in the protein levels of GluA4 suggesting postsynaptic mechanisms of expression. The findings demonstrate that synchronous activity in the immature CA3-CA1 circuitry is critical for the induction and maintenance of glutamatergic synapses and underscores the importance of temporal activity patterns in shaping the synaptic circuitry during development.

  3. The Cryptococcus neoformans alkaline response pathway: identification of a novel rim pathway activator.

    Directory of Open Access Journals (Sweden)

    Kyla S Ost

    2015-04-01

    Full Text Available The Rim101/PacC transcription factor acts in a fungal-specific signaling pathway responsible for sensing extracellular pH signals. First characterized in ascomycete fungi such as Aspergillus nidulans and Saccharomyces cerevisiae, the Rim/Pal pathway maintains conserved features among very distantly related fungi, where it coordinates cellular adaptation to alkaline pH signals and micronutrient deprivation. However, it also directs species-specific functions in fungal pathogens such as Cryptococcus neoformans, where it controls surface capsule expression. Moreover, disruption of the Rim pathway central transcription factor, Rim101, results in a strain that causes a hyper-inflammatory response in animal infection models. Using targeted gene deletions, we demonstrate that several genes encoding components of the classical Rim/Pal pathway are present in the C. neoformans genome. Many of these genes are in fact required for Rim101 activation, including members of the ESCRT complex (Vps23 and Snf7, ESCRT-interacting proteins (Rim20 and Rim23, and the predicted Rim13 protease. We demonstrate that in neutral/alkaline pH, Rim23 is recruited to punctate regions on the plasma membrane. This change in Rim23 localization requires upstream ESCRT complex components but does not require other Rim101 proteolysis components, such as Rim20 or Rim13. Using a forward genetics screen, we identified the RRA1 gene encoding a novel membrane protein that is also required for Rim101 protein activation and, like the ESCRT complex, is functionally upstream of Rim23-membrane localization. Homologs of RRA1 are present in other Cryptococcus species as well as other basidiomycetes, but closely related genes are not present in ascomycetes. These findings suggest that major branches of the fungal Kingdom developed different mechanisms to sense and respond to very elemental extracellular signals such as changing pH levels.

  4. Hemispheric asymmetry of visual scene processing in the human brain: evidence from repetition priming and intrinsic activity.

    Science.gov (United States)

    Stevens, W Dale; Kahn, Itamar; Wig, Gagan S; Schacter, Daniel L

    2012-08-01

    Asymmetrical specialization of cognitive processes across the cerebral hemispheres is a hallmark of healthy brain development and an important evolutionary trait underlying higher cognition in humans. While previous research, including studies of priming, divided visual field presentation, and split-brain patients, demonstrates a general pattern of right/left asymmetry of form-specific versus form-abstract visual processing, little is known about brain organization underlying this dissociation. Here, using repetition priming of complex visual scenes and high-resolution functional magnetic resonance imaging (MRI), we demonstrate asymmetrical form specificity of visual processing between the right and left hemispheres within a region known to be critical for processing of visual spatial scenes (parahippocampal place area [PPA]). Next, we use resting-state functional connectivity MRI analyses to demonstrate that this functional asymmetry is associated with differential intrinsic activity correlations of the right versus left PPA with regions critically involved in perceptual versus conceptual processing, respectively. Our results demonstrate that the PPA comprises lateralized subregions across the cerebral hemispheres that are engaged in functionally dissociable yet complementary components of visual scene analysis. Furthermore, this functional asymmetry is associated with differential intrinsic functional connectivity of the PPA with distinct brain areas known to mediate dissociable cognitive processes.

  5. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, J C; Christensen, Ib Jarle

    2004-01-01

    BACKGROUND: Postoperative bacterial infectious complications are frequent in patients with colorectal cancer (CRC), with subsequent increased recurrence rates and poor prognosis. Deficiency of the mannan-binding lectin (MBL) complement activation pathway may cause increased risk of infection...... with colorectal cancer compared with healthy persons. However, similar frequencies of MBL pathway deficiency are observed in patients and healthy persons....... in certain patient groups. It is hypothesized that a deficient MBL pathway might be more frequent among patients with CRC than in healthy individuals. The MBL pathway was therefore evaluated in serum obtained preoperatively from 193 patients with primary CRC and in serum from 150 healthy volunteers. METHODS...

  6. Functional Trade-Offs in Promiscuous Enzymes Cannot Be Explained by Intrinsic Mutational Robustness of the Native Activity.

    Directory of Open Access Journals (Sweden)

    Miriam Kaltenbach

    2016-10-01

    Full Text Available The extent to which an emerging new function trades off with the original function is a key characteristic of the dynamics of enzyme evolution. Various cases of laboratory evolution have unveiled a characteristic trend; a large increase in a new, promiscuous activity is often accompanied by only a mild reduction of the native, original activity. A model that associates weak trade-offs with "evolvability" was put forward, which proposed that enzymes possess mutational robustness in the native activity and plasticity in promiscuous activities. This would enable the acquisition of a new function without compromising the original one, reducing the benefit of early gene duplication and therefore the selection pressure thereon. Yet, to date, no experimental study has examined this hypothesis directly. Here, we investigate the causes of weak trade-offs by systematically characterizing adaptive mutations that occurred in two cases of evolutionary transitions in enzyme function: (1 from phosphotriesterase to arylesterase, and (2 from atrazine chlorohydrolase to melamine deaminase. Mutational analyses in various genetic backgrounds revealed that, in contrast to the prevailing model, the native activity is less robust to mutations than the promiscuous activity. For example, in phosphotriesterase, the deleterious effect of individual mutations on the native phosphotriesterase activity is much larger than their positive effect on the promiscuous arylesterase activity. Our observations suggest a revision of the established model: weak trade-offs are not caused by an intrinsic robustness of the native activity and plasticity of the promiscuous activity. We propose that upon strong adaptive pressure for the new activity without selection against the original one, selected mutations will lead to the largest possible increases in the new function, but whether and to what extent they decrease the old function is irrelevant, creating a bias towards initially weak

  7. Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways.

    Science.gov (United States)

    Taylor, Ruth D T; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

    2014-01-01

    The slow afterhyperpolarizing current (sIAHP ) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP , resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons.

  8. High Intrinsic Catalytic Activity of Two-Dimensional Boron Monolayers for Hydrogen Evolution Reaction

    CERN Document Server

    Shi, Li; Ouyang, Yixin; Wang, Jinlan

    2016-01-01

    Two-dimensional (2D) boron monolayers have been successfully synthesized on silver substrate very recently. Their potential application is thus of great significance. In this work, we explore the possibility of boron monolayers (BMs) as electrocatalysts for hydrogen evolution reaction (HER) by first-principle method. Our calculations show that the BMs are active catalysts for HER with nearly zero free energy of hydrogen adsorption, metallic conductivity and plenty of active sites in the basal plane. The effect of the substrate on the HER activity is further assessed. It is found that the substrate has a positive effect on the HER performance caused by the competitive effect of mismatch strain and charge transfer. The indepth understanding of the structure dependent HER activity is also provided.

  9. Mitogen-activated protein kinase pathways in osteoblasts.

    Science.gov (United States)

    Greenblatt, Matthew B; Shim, Jae-Hyuck; Glimcher, Laurie H

    2013-01-01

    Mitogen-activated protein kinases (MAPKs) are ancient signal transducers well characterized as mediators of inflammation and neoplastic transformation. Recent work has expanded our understanding of their developmental functions, particularly in the regulation of bone mass via control of osteoblast differentiation. Here, we review the functions of MAPK pathways in osteoblasts, including a consideration of MAPK substrates. In particular, MAPKs function to regulate the key transcriptional mediators of osteoblast differentiation, with ERK and p38 MAPKs phosphorylating RUNX2, the master regulator of osteoblast differentiation. ERK also activates RSK2, which in turn phosphorylates ATF4, a transcriptional regulator of late-stage osteoblast synthetic functions. The MAP3Ks and MAP2Ks upstream of MAPKs have also been investigated, and significant differences have been found in the wiring of MAPK pathways in osteoblasts relative to other tissues. Thus, the investigation of MAPKs in osteoblasts has both revealed critical mechanisms for the maintenance of bone mass and added to our understanding of how the individual components of MAPK pathways function in concert in a complex in vivo system.

  10. Redox enzyme-mimicking activities of CeO2 nanostructures: Intrinsic influence of exposed facets

    Science.gov (United States)

    Yang, Yushi; Mao, Zhou; Huang, Wenjie; Liu, Lihua; Li, Junli; Li, Jialiang; Wu, Qingzhi

    2016-10-01

    CeO2 nanoparticles (NPs) have been well demonstrated as an antioxidant in protecting against oxidative stress-induced cellular damages and a potential therapeutic agent for various diseases thanks to their redox enzyme-mimicking activities. The Ce3+/Ce4+ ratio and oxygen vacancies on the surface have been considered as the major originations responsible for the redox enzyme-mimicking activities of CeO2 NPs. Herein, CeO2 nanostructures (nanocubes and nanorods) exposed different facets were synthesized via a facile hydrothermal method. The characterizations by X-ray photoelectron spectroscopy, Raman spectroscopy, and UV-Vis spectroscopy show that the Ce3+/Ce4+ ratio and oxygen vacancy content on the surfaces of as-synthesized CeO2 nanostructures are nearly at the same levels. Meanwhile, the enzymatic activity measurements indicate that the redox enzyme-mimicking activities of as-synthesized CeO2 nanostructures are greatly dependent on their exposed facets. CeO2 nanocubes with exposed {100} facets exhibit a higher peroxidase but lower superoxide dismutase activity than those of the CeO2 nanorods with exposed {110} facets. Our results provide new insights into the redox enzyme-mimicking activities of CeO2 nanostructures, as well as the design and synthesis of inorganic nanomaterials-based artificial enzymes.

  11. The Intrinsic Eddington Ratio Distribution of Active Galactic Nuclei in Star-forming Galaxies from the Sloan Digital Sky Survey

    CERN Document Server

    Jones, M L; Black, C S; Hainline, K N; DiPompeo, M A; Goulding, A D

    2016-01-01

    An important question in extragalactic astronomy concerns the distribution of black hole accretion rates of active galactic nuclei (AGN). Based on observations at X-ray wavelengths, the observed Eddington ratio distribution appears as a power law, while optical studies have often yielded a lognormal distribution. There is increasing evidence that these observed discrepancies may be due to contamination by star formation and other selection effects. Using a sample of galaxies from the Sloan Digital Sky Survey Data Release 7, we test if an intrinsic Eddington ratio distribution that takes the form of a Schechter function is consistent with previous work that suggests that young galaxies in optical surveys have an observed lognormal Eddington ratio distribution. We simulate the optical emission line properties of a population of galaxies and AGN using a broad instantaneous luminosity distribution described by a Schechter function near the Eddington limit. This simulated AGN population is then compared to observe...

  12. Genetic evidence of an accessory activity required specifically for cubilin brush-border expression and intrinsic factor-cobalamin absorption.

    Science.gov (United States)

    Xu, D; Kozyraki, R; Newman, T C; Fyfe, J C

    1999-11-15

    Cubilin is a high molecular weight multiligand receptor that mediates intestinal absorption of intrinsic factor-cobalamin and selective protein reabsorption in renal tubules. The genetic basis of selective intestinal cobalamin malabsorption with proteinuria was investigated in a canine model closely resembling human Imerslund-Gräsbeck syndrome caused by cubilin mutations. Canine CUBN cDNA was cloned and sequenced, showing high identity with human and rat CUBN cDNAs. An intragenic CUBN marker was identified in the canine family and used to test the hypothesis of genetic linkage of the disease and CUBN loci. Linkage was rejected, indicating that the canine disorder resembling Imerslund-Gräsbeck syndrome is caused by defect of a gene product other than cubilin. These results imply that there may be locus heterogeneity among human kindreds with selective intestinal cobalamin malabsorption and proteinuria and that normal brush-border expression of cubilin requires the activity of an accessory protein.

  13. SNIP1: a new activator of HSE signaling pathway.

    Science.gov (United States)

    Li, Qiang; An, Jian; Liu, Xianghua; Zhang, Mingjun; Ling, Yichen; Wang, Chenji; Zhao, Jing; Yu, Long

    2012-03-01

    In the last 10 years, more and more attention has been focused on SNIP1 (Smad nuclear interacting protein 1), which functions as a transcriptional coactivator. We report here that through quantitative real-time PCR analysis in 18 different human tissues, SNIP1 was found to be expressed ubiquitously. When overexpressed in HeLa cells, SNIP1-EGFP fused protein exhibited a nuclear localization with a characteristic subnuclear distribution in speckles or formed larger discrete nuclear bodies in some cells. Reporter gene assay showed that overexpression of SNIP1 in HEK 293 cells or H1299 cells strongly activated the HSE signaling pathway. Moreover, SNIP1 could selectively regulate the transcription of HSP70A1A and HSP27. Taken together, our findings suggest that SNIP1 might also be a positive regulator of HSE signaling pathway.

  14. Suppressed intrinsic catalytic activity of GLUT1 glucose transporters in insulin-sensitive 3T3-L1 adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, S.A.; Buxton, J.M.; Czech, M.P. (Univ. of Massachusetts Medical Center, Worcester (United States))

    1991-09-01

    Previous studies indicated that the erythroid-type (GLUT1) glucose transporter isoform contributes to basal but not insulin-stimulated hexose transport in mouse 3T3-L1 adipocytes. In the present studies it was found that basal hexose uptake in 3T3-L1 adipocytes was about 50% lower than that in 3T3-L1 or CHO-K1 fibroblasts. Intrinsic catalytic activities of GLUT1 transporters in CHO-K1 and 3T3-L1 cells were compared by normalizing these hexose transport rates to GLUT1 content on the cell surface, as measured by two independent methods. Cell surface GLUT1 levels in 3T3-L1 fibroblasts and adipocytes were about 10- and 25-fold higher, respectively, than in CHO-K1 fibroblasts, as assessed with an anti-GLUT1 exofacial domain antiserum, delta. The large excess of cell surface GLUT1 transporters in 3T3-L1 adipocytes relative to CHO-K1 fibroblasts was confirmed by GLUT1 protein immunoblot analysis and by photoaffinity labeling (with 3-({sup 125}I)iodo-4-azidophenethylamido-7-O-succinyldeacetylforskolin) of glucose transporters in isolated plasma membranes. Thus, GLUT1 intrinsic activity is markedly reduced in 3T3-L1 fibroblasts compared with the CHO-K1 fibroblasts, and further reduction occurs upon differentiation to adipocytes. The authors conclude that a mechanism that markedly suppresses basal hexose transport catalyzed by GLUT1 is a major contributor to the dramatic insulin sensitivity of glucose uptake in 3T3-L1 adipocytes.

  15. Keeping women active: an examination of the impacts of self-efficacy, intrinsic motivation, and leadership on women's persistence in physical activity.

    Science.gov (United States)

    Lloyd, Kathleen M; Little, Donna E

    2010-10-01

    Physical inactivity in women is a worldwide problem that has not only been well-documented but has provoked much government concern and policy activity. However, an even more important issue is encouraging women's persistence in physical activity. The purpose of this study was to examine the links between women's experiences of participation in a government-funded physical activity festival, their intentions to continue participation, and their participation behavior six months after the festival. Results from semi-structured, in-depth interviews with 20 women revealed that enhanced self-efficacy, intrinsic motivation, and supportive leadership had motivated the women's future intentions to participate. Follow-up surveys showed their levels of interest and participation in physical activity had been maintained. These results enhance our understanding of the relationship between key outcomes of women's physical activity participation and their persistence in physical activity.

  16. Pathways to URM Retention: IBP's Professional Development and Mentoring Activities

    Science.gov (United States)

    Johnson, A.; Williamson Whitney, V.; Ricciardi, L.; Detrick, L.; Siegfried, D.; Fauver, A.; Ithier-Guzman, W.; Thomas, S. H.; Valaitis, S.

    2013-05-01

    As a not for profit organization, the Institute for Broadening Participation (IBP) hosts a variety of initiatives designed to increase the retention of underrepresented minority (URM) students pursuing pathways in STEM. IBP also assists with formative program evaluation design and implementation to help strengthen URM recruitment and retention elements. Successful initiatives include virtual and face-to-face components that bring together URM students with established URM and other scientists in academia, government and industry. These connections provide URMs with mentoring, networking opportunities, and professional skill development contributing to an improved retention rate of URM students. IBP's initiatives include the NASA One Stop Shopping Initiative (NASA OSSI), Pathways to Ocean Science and Engineering, and the Minorities Striving and Pursuing Higher Degrees of Success (MS PHD'S) in Earth System Science (ESS) Professional Development Program. The NASA OSSI recruits and facilitates student engagement in NASA education and employment opportunities. Pathways to Ocean Science connects and supports URM students with Ocean Science REU programs and serves as a resource for REU program directors. Pathways to Engineering has synthesized mentoring resources into an online mentoring manual for URM students that has been extensively vetted by mentoring experts throughout the country. The mentoring manual, which is organized by roles, provides undergraduates, graduates, postdocs, faculty and project directors with valuable resources. MS PHD'S, one of IBP's longest running and most successful initiatives, focuses on increasing the retention rate of URM students receiving advanced degrees in ESS. The program addresses barriers to retention in ESS including isolation, lack of preparation and professional development, and lack of mentoring. Program activities center on peer-to-peer community building, professional development exercises, networking experiences, one

  17. Novel zinc alginate hydrogels prepared by internal setting method with intrinsic antibacterial activity.

    Science.gov (United States)

    Straccia, Maria Cristina; d'Ayala, Giovanna Gomez; Romano, Ida; Laurienzo, Paola

    2015-07-10

    In this paper, a controlled gelation of alginate was performed for the first time using ZnCO3 and GDL. Uniform and transparent gels were obtained and investigated as potential wound dressings. Homogeneity, water content, swelling capability, water evaporation rate, stability in normal saline solution, mechanical properties and antibacterial activity were assessed as a function of zinc concentration. Gelation rate increased at increasing zinc content, while a decrease in water uptake and an improvement of stability were found. Release of zinc in physiological environments showed that concentration of zinc released in solution lies below the cytotoxicity level. Hydrogels showed antimicrobial activity against Escherichia coli. The hydrogel with highest zinc content was stabilized with calcium by immersion in a calcium chloride solution. The resulting hydrogel preserved homogeneity and antibacterial activity. Furthermore, it showed even an improvement of stability and mechanical properties, which makes it suitable as long-lasting wound dressing. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Albinism-causing mutations in recombinant human tyrosinase alter intrinsic enzymatic activity.

    Directory of Open Access Journals (Sweden)

    Monika B Dolinska

    Full Text Available BACKGROUND: Tyrosinase (TYR catalyzes the rate-limiting, first step in melanin production and its gene (TYR is mutated in many cases of oculocutaneous albinism (OCA1, an autosomal recessive cause of childhood blindness. Patients with reduced TYR activity are classified as OCA1B; some OCA1B mutations are temperature-sensitive. Therapeutic research for OCA1 has been hampered, in part, by the absence of purified, active, recombinant wild-type and mutant human enzymes. METHODOLOGY/PRINCIPAL FINDINGS: The intra-melanosomal domain of human tyrosinase (residues 19-469 and two OCA1B related temperature-sensitive mutants, R422Q and R422W were expressed in insect cells and produced in T. ni larvae. The short trans-membrane fragment was deleted to avoid potential protein insolubility, while preserving all other functional features of the enzymes. Purified tyrosinase was obtained with a yield of >1 mg per 10 g of larval biomass. The protein was a monomeric glycoenzyme with maximum enzyme activity at 37°C and neutral pH. The two purified mutants when compared to the wild-type protein were less active and temperature sensitive. These differences are associated with conformational perturbations in secondary structure. CONCLUSIONS/SIGNIFICANCE: The intramelanosomal domains of recombinant wild-type and mutant human tyrosinases are soluble monomeric glycoproteins with activities which mirror their in vivo function. This advance allows for the structure - function analyses of different mutant TYR proteins and correlation with their corresponding human phenotypes; it also provides an important tool to discover drugs that may improve tyrosinase activity and treat OCA1.

  19. BH3 mimetics activate multiple pro-autophagic pathways.

    Science.gov (United States)

    Malik, S A; Orhon, I; Morselli, E; Criollo, A; Shen, S; Mariño, G; BenYounes, A; Bénit, P; Rustin, P; Maiuri, M C; Kroemer, G

    2011-09-15

    The BH3 mimetic ABT737 induces autophagy by competitively disrupting the inhibitory interaction between the BH3 domain of Beclin 1 and the anti-apoptotic proteins Bcl-2 and Bcl-X(L), thereby stimulating the Beclin 1-dependent allosteric activation of the pro-autophagic lipid kinase VPS34. Here, we examined whether ABT737 stimulates other pro-autophagic signal-transduction pathways. ABT737 caused the activating phosphorylation of AMP-dependent kinase (AMPK) and of the AMPK substrate acetyl CoA carboxylase, the activating phosphorylation of several subunits of the inhibitor of NF-κB (IκB) kinase (IKK) and the hyperphosphorylation of the IKK substrate IκB, inhibition of the activity of mammalian target of rapamycin (mTOR) and consequent dephosphorylation of the mTOR substrate S6 kinase. In addition, ABT737 treatment dephosphorylates (and hence likewise inhibits) p53, glycogen synthase kinase-3 and Akt. All these effects were shared by ABT737 and another structurally unrelated BH3 mimetic, HA14-1. Functional experiments revealed that pharmacological or genetic inhibition of IKK, Sirtuin and the p53-depleting ubiquitin ligase MDM2 prevented ABT737-induced autophagy. These results point to unexpected and pleiotropic pro-autophagic effects of BH3 mimetics involving the modulation of multiple signalling pathways.

  20. Intrinsic effects of gold nanoparticles on proliferation and invasion activity in SGC-7901 cells.

    Science.gov (United States)

    Wu, Yucheng; Zhang, Qingqing; Ruan, Zhongbao; Yin, Yigang

    2016-03-01

    Although biomedical applications of functionalized nanoparticles have taken significant strides, biological characterization of unmodified nanoparticles remains unclear. In the present study, we investigated the cell viability and invasion activity of gastric cancer cells after treatment with gold nanoparticles. The growth of SGC-7901 cells was inhibited significantly after treatment with 5-nm gold nanoparticles, and the cell invasion decreased markedly. These effects were not seen by different size gold nanoparticles (10, 20 and 40 nm). The attenuated invasion activity may be associated with the decreased expression of matrix metalloproteinase 9 and intercellular adhesion molecule-1. These data indicated that the response of SGC-7901 cells to gold nanoparticles was strongly associated with their unique size-dependent physiochemical properties. Therefore, we provided new evidence for the effect of gold nanoparticles on gastric cancer cell proliferation and invasion in vitro, making a contribution to the application of gold nanoparticles to novel therapies in gastric cancer.

  1. Intermittent hypoxia-activated cyclooxygenase pathway: role in atherosclerosis.

    Science.gov (United States)

    Gautier-Veyret, Elodie; Arnaud, Claire; Bäck, Magnus; Pépin, Jean-Louis; Petri, Marcelo H; Baguet, Jean-Philippe; Tamisier, Renaud; Lévy, Patrick; Stanke-Labesque, Françoise

    2013-08-01

    Intermittent hypoxia, the main stimulus of obstructive sleep apnoea (OSA), induces inflammation, leading to early atherosclerosis. Whether the cyclooxygenase (COX) pathway contributes to intermittent hypoxia-induced atherosclerosis remains to be determined. We studied the effects of 8-weeks of intermittent hypoxia exposure on COX-pathway gene expression and atherosclerosis, and the influence of COX-1 inhibition by SC-560 on atherosclerosis progression in aortas of apolipoprotein E(-/-) mice. Urinary 11-dehydrothromboxane B2 (11-dTXB2) was assessed in 50 OSA subjects free of cardiovascular risk factor matched for age and body mass index with 25 controls, and 56 OSA with cardiovascular risk factor. Intermittent hypoxia significantly increased atherosclerotic lesion sizes, mRNA levels of COX-1 and thromboxane synthase (TXBS). Lesion sizes correlated to COX-1 (r = 0.654, p = 0.0003) and TXBS (r = 0.693, pintermittent hypoxia mice only (p = 0.04). Urinary 11-dTXB2 was similar in OSA subjects free of cardiovascular risk factor and controls, but was increased by 13% (p = 0.007) in OSA subjects with cardiovascular risk factor compared with those without. Although OSA itself was not associated with increased urinary 11-dTXB2 concentration, the COX-1 pathway was activated in intermittent hypoxia-exposed mice and in OSA subjects presenting with cardiovascular risk factor, and may contribute to intermittent hypoxia-induced atherogenesis. COX-1 inhibition could be of clinical interest in the prevention of cardiovascular morbidity in OSA.

  2. Inhibition of the intrinsic factor X activating complex by protein S: evidence for a specific binding of protein S to factor VIII

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    Protein S is a vitamin K-dependent nonenzymatic anticoagulant protein that acts as a cofactor to activated protein C. Recently it was shown that protein S inhibits the prothrombinase reaction independent of activated protein C. In this study, we show that protein S can also inhibit the intrinsic

  3. Inhibition of the intrinsic factor X activating complex by protein S: evidence for a specific binding of protein S to factor VIII

    NARCIS (Netherlands)

    Koppelman, S.J.

    1995-01-01

    Protein S is a vitamin K-dependent nonenzymatic anticoagulant protein that acts as a cofactor to activated protein C. Recently it was shown that protein S inhibits the prothrombinase reaction independent of activated protein C. In this study, we show that protein S can also inhibit the intrinsic fac

  4. Cardiac Shock Wave Therapy Attenuates H9c2 Myoblast Apoptosis by Activating the AKT Signal Pathway

    Directory of Open Access Journals (Sweden)

    Weiwei Yu

    2014-04-01

    Full Text Available Background: Previous studies have demonstrated that Cardiac Shock Wave Therapy (CSWT improves myocardial perfusion and cardiac function in a porcine model of chronic myocardial ischemia and also ameliorates myocardial ischemia in patients with severe coronary artery disease (CAD. Apoptosis plays a key role in ischemic myocardial pathogenesis. However, it remains unclear whether CSWT is beneficial for ischemia/hypoxia (I/H-induced myocardial cell apoptosis and by which mechanism CSWT could improve heart function. We put forward the hypothesis that CSWT might protect heart function during ischemia/hypoxia by decreasing apoptosis. Methods: We generated ischemia/hypoxia (I/H-induced apoptosis in the H9c2 myoblast cell line to examine the CSWT function and possible mechanisms. H9c2 cells were treated under hypoxic serum-starved conditions for 24 h and then treated with or without CSWT (500 shots, 0.06, 0.09, 0.12mJ/mm2. The apoptotic cell rate was determined by flow cytometry assay, cell viability was examined by the MTT assay, nuclear fragmentation was detected by Hoechst 33342 staining, and the mitochondrial-mediated intrinsic pathway of apoptosis was assessed by the expression of Bax and Bcl-2 protein and Caspase3 activation. Results: First, apoptosis could be induced by ischemia/hypoxia in H9c2 cells. Second, CSWT attenuates the cell death and decreases the H9c2 cell apoptosis rate induced by ischemia and hypoxia. Third, CSWT suppresses the expression of apoptosis molecules that regulate the intrinsic pathway of apoptosis in H9c2 cells. Fourth, CSWT increases the phosphorylation of AKT, which indicates the activation of the PI3K-AKT pathway. Conclusions: These results indicate that CSWT exerts a protective effect against I/H-induced cell death, potentially by preventing the activation of components of the mitochondrial-dependent intrinsic apoptotic pathway. We also demonstrate that the PI3K-Akt pathway may be involved in the CSWT effects on

  5. Bioreactor Transient Exposure Activates Specific Neurotrophic Pathway in Cortical Neurons

    Science.gov (United States)

    Zimmitti, V.; Benedetti, E.; Caracciolo, V.; Sebastiani, P.; Di Loreto, S.

    2010-02-01

    Altered gravity forces might influence neuroplasticity and can provoke changes in biochemical mechanisms. In this contest, neurotrophins have a pivotal role, particularly nerve growth factor (NGF) and brain derived neurotrophic factor (BDNF). A suspension of dissociated cortical cells from rat embryos was exposed to 24 h of microgravity before plating in normal adherent culture system. Expression and transductional signalling pathways of NGF and BDNF were assessed at the end of maturational process (8-10 days in vitro). Rotating wall vessel bioreactor (RWV) pre-exposition did not induce changes in NGF expression and its high affinity receptor TrkA. On the contrary both BDNF expression and its high affinity receptor TrkB were strongly up-regulated, inducing Erk-5, but not Erk-1/2 activation and, in turn, MEF2C over-expression and activation. According to our previous and present results, we postulate that relatively short microgravitational stimuli, applied to neural cells during the developmental stage, exert a long time activation of specific neurotrophic pathways.

  6. Notch pathway activation is associated with pancreatic cancer treatment failure.

    Science.gov (United States)

    Lee, Jin Young; Song, Si Young; Park, Jeong Youp

    2014-01-01

    Pancreatic cancer is resistant to conventional treatment. The aim of the study was to confirm the hypothesis that changes in cancer stem cells (CSCs) and developmental pathway after treatment was responsible for treatment failure in pancreatic cancer. After recovery from a gemcitabine treatment, the percentage of pancreatic cancer CSCs and Notch pathway in BxPC3 and HPAC pancreatic cancer cell lines were analyzed by FACS (CD24 and CD44) and western blot (Notch1, Hes1, β-catenin, and pAKT). The effect of DAPT, a gamma-secretase inhibitor, was similarly investigated. The association between immunohistochemical expression of Hes1 and survival was analyzed. The percentage of CD24(+)CD44(+) cells was higher in gemcitabine-treated BxPC3 and HPAC cells than at pre-treatment. CD24(+)CD44(+) cells sorted from the gemcitabine-treated cell lines showed higher migration and invasion ability than CD24(-)CD44(-) or CD24(-)CD44(+) cells from the same cell lines. Western blot analysis showed an increased expression of Notch1 and Hes1 in gemcitabine-treated cell lines. The overall survival of pancreatic cancer patients with strong expression of Hes1 was shorter than that in patients with no or weak expression (11.1 vs. 21.6 months, P = 0.036). Treatment with DAPT reversed the increase in Hes1, β-catenin, and pAKT expression and the proportion of CD24(+)CD44(+) cells in gemcitabine-treated cell lines. The treatment also decreased migration and invasion ability. Our data suggested that an increase in CSCs and activation of the Notch pathway might contribute to the failure of treatment in pancreatic cancer. Notch pathway can be a potential target to overcome treatment failure. Copyright © 2013 IAP and EPC. Published by Elsevier B.V. All rights reserved.

  7. Cell Intrinsic Galectin-3 Attenuates Neutrophil ROS-Dependent Killing of Candida by Modulating CR3 Downstream Syk Activation

    Science.gov (United States)

    Wu, Sheng-Yang; Huang, Juin-Hua; Chen, Wen-Yu; Chan, Yi-Chen; Lin, Chun-Hung; Chen, Yee-Chun; Liu, Fu-Tong; Wu-Hsieh, Betty A.

    2017-01-01

    Invasive candidiasis is a leading cause of nosocomial bloodstream infection. Neutrophils are the important effector cells in host resistance to candidiasis. To investigate the modulation of neutrophil fungicidal function will advance our knowledge on the control of candidiasis. While recombinant galectin-3 enhances neutrophil phagocytosis of Candida, we found that intracellular galectin-3 downregulates neutrophil fungicidal functions. Co-immunoprecipitation and immunofluorescence staining reveal that cytosolic gal3 physically interacts with Syk in neutrophils after Candida stimulation. Gal3−/− neutrophils have higher level of Syk activation as well as greater abilities to generate reactive oxygen species (ROS) and kill Candida than gal3+/+ cells. While galectin-3 deficiency modulates neutrophil and macrophage activation and the recruitment of monocytes and dendritic cells, the deficiency does not affect the numbers of infiltrating neutrophils or macrophages. Galectin-3 deficiency ameliorates systemic candidiasis by reducing fungal burden, renal pathology, and mortality. Adoptive transfer experiments demonstrate that cell intrinsic galectin-3 negatively regulates neutrophil effector functions against candidiasis. Reducing galectin-3 expression or activity by siRNA or gal3 inhibitor TD139 enhances human neutrophil ROS production. Mice treated with TD139 have enhanced ability to clear the fungus. Our work unravels the mechanism by which galectin-3 regulates Syk-dependent neutrophil fungicidal functions and raises the possibility that blocking gal3 in neutrophils may be a promising therapeutic strategy for treating systemic candidiasis. PMID:28217127

  8. Longitudinal intrinsic brain activity changes in cirrhotic patients before and one month after liver transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Yue; Huang, Li Xiang; Xie, Shuang [Dept. of Radiology, Tianjin First Central Hospital, Tianjin (China); and others

    2017-04-15

    To evaluate the spontaneous brain activity alterations in liver transplantation (LT) recipients using resting-state functional MRI. Twenty cirrhotic patients as transplant candidates and 25 healthy controls (HCs) were included in this study. All patients repeated the MRI study one month after LT. Amplitude of low-frequency fluctuation (ALFF) values were compared between cirrhotic patients (both pre- and post-LT) and HCs as well as between the pre- and post-LT groups. The relationship between ALFF changes and venous blood ammonia levels and neuropsychological tests were investigated using Pearson's correlation analysis. In the cirrhotic patients, decreased ALFF in the vision-related regions (left lingual gyrus and calcarine), sensorimotor-related regions (left postcentral gyrus and middle cingulate cortex), and the default-mode network (bilateral precuneus and left inferior parietal lobule) were restored, and the increased ALFF in the temporal and frontal lobe improved in the early period after LT. The ALFF decreases persisted in the right supplementary motor area, inferior parietal lobule, and calcarine. The ALFF changes in the right precuneus were negatively correlated with changes in number connection test-A scores (r = 0.507, p < 0.05). LT improved spontaneous brain activity and the results for associated cognition tests. However, decreased ALFF in some areas persisted, and new-onset abnormal ALFF were possible, indicating that complete cognitive function recovery may need more time.

  9. A novel cisplatin mediated apoptosis pathway is associated with acid sphingomyelinase and FAS proapoptotic protein activation in ovarian cancer.

    Science.gov (United States)

    Maurmann, L; Belkacemi, L; Adams, N R; Majmudar, P M; Moghaddas, S; Bose, R N

    2015-07-01

    Platinum-based anticancer drugs, including cisplatin and carboplatin, have been cornerstones in the treatment of solid tumors. We report here that these DNA-damaging agents, particularly cisplatin, induce apoptosis through plasma membrane disruption, triggering FAS death receptor via mitochondrial (intrinsic) pathways. Our objectives were to: quantify the composition of membrane metabolites; and determine the potential involvement of acid sphingomyelinase (ASMase) in the FAS-mediated apoptosis in ovarian cancer after cisplatin treatment. The resulting analysis revealed enhanced apoptosis as measured by: increased phosphocholine, and glycerophosphocholine; elevated cellular energetics; and phosphocreatine and nucleoside triphosphate concentrations. The plasma membrane alterations were accompanied by increased ASMase activity, leading to the upregulation of FAS, FASL and related pro-apoptotic BAX and PUMA genes. Moreover FAS, FASL, BAX, PUMA, CASPASE-3 and -9 proteins were upregulated. Our findings implicate ASMase activity and the intrinsic pathways in cisplatin-mediated membrane demise, and contribute to our understanding of the mechanisms by which ovarian tumors may become resistant to cisplatin.

  10. Intrinsic activation: the relationship between biomass inorganic content and porosity formation during pyrolysis.

    Science.gov (United States)

    Stratford, James P; Hutchings, Tony R; de Leij, Frans A A M

    2014-05-01

    The utility of pyrolytic carbons is closely related to their porosity and surface area, there is a clear benefit to the development of biomass pyrolysis processes which produce highly porous carbons. The results presented in this work demonstrate that by using biomass precursors with high inorganic content along with specified process conditions, carbons can be consistently produced with specific surface areas between 900 and 1600 m(2)/g. Results from 12 different source materials show that the formation of increased porosity in pyrolytic carbons is strongly associated with the presence of inorganic elements in the precursors including: magnesium, potassium and sulfur. It was found that pyrolysis of macro-algae can produce especially high specific surface area carbons (mean: 1500 m(2)/g), without externally applied activating agents. Using cheap readily available agricultural residues such as oilseed rape straw, pyrolytic carbons can be produced with specific surface areas of around 950 m(2)/g.

  11. Sulforaphane-induced apoptosis in human leukemia HL-60 cells through extrinsic and intrinsic signal pathways and altering associated genes expression assayed by cDNA microarray.

    Science.gov (United States)

    Shang, Hung-Sheng; Shih, Yung-Luen; Lee, Ching-Hsiao; Hsueh, Shu-Ching; Liu, Jia-You; Liao, Nien-Chieh; Chen, Yung-Liang; Huang, Yi-Ping; Lu, Hsu-Feng; Chung, Jing-Gung

    2017-01-01

    Sulforaphane (SFN), one of the isothiocyanates, is a biologically active compound extracted from cruciferous vegetables, and has been shown to induce cytotoxic effects on many human cancer cells including human leukemia cells. However, the exact molecular mechanism and altered gene expression associated with apoptosis is unclear. In this study, we investigated SFN-induced cytotoxic effects and whether or not they went through cell-cycle arrest and induction of apoptosis and further examined molecular mechanism and altered gene expression in human leukemia HL-60 cells. Cell viability, cell-cycle distribution, sub-G1 (apoptosis), reactive oxygen species (ROS) and Ca(2+) production, levels of mitochondrial membrane potential (ΔΨm ), and caspase-3, -8, and -9 activities were assayed by flow cytometry. Apoptosis-associated proteins levels and gene expressions were examined by Western blotting and cDNA microarray assays, respectively. Results indicated that SFN decreased viable cells, induced G2/M phase arrest and apoptosis based on sub-G1 phase development. Furthermore, SFN increased ROS and Ca(2+) production and decreased the levels of ΔΨm and activated caspase-3, -8, and -9 activities in HL-60 cells. SFN significantly upregulated the expression of BAX, Bid, Fas, Fas-L, caspase-8, Endo G, AIF, and cytochrome c, and inhibited the antiapoptotic proteins such as Bcl-x and XIAP, that is associated with apoptosis. We also used cDNA microarray to confirm several gene expressions such as caspase -8, -3, -4, -6, and -7 that are affected by SFN. Those results indicated that SFN induced apoptosis in HL-60 cells via Fas- and mitochondria-dependent pathways. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 311-328, 2017.

  12. Complement alternative pathway activation in human nonalcoholic steatohepatitis.

    Directory of Open Access Journals (Sweden)

    Filip M Segers

    Full Text Available The innate immune system plays a major role in the pathogenesis of nonalcoholic steatohepatitis (NASH. Recently we reported complement activation in human NASH. However, it remained unclear whether the alternative pathway of complement, which amplifies C3 activation and which is frequently associated with pathological complement activation leading to disease, was involved. Here, alternative pathway components were investigated in liver biopsies of obese subjects with healthy livers (n = 10 or with NASH (n = 12 using quantitative PCR, Western blotting, and immunofluorescence staining. Properdin accumulated in areas where neutrophils surrounded steatotic hepatocytes, and colocalized with the C3 activation product C3c. C3 activation status as expressed by the C3c/native C3 ratio was 2.6-fold higher (p<0.01 in subjects with NASH despite reduced native C3 concentrations (0.94±0.12 vs. 0.57±0.09; p<0.01. Hepatic properdin levels positively correlated with levels of C3c (rs = 0.69; p<0.05 and C3c/C3 activation ratio (rs = 0.59; p<0.05. C3c, C3 activation status (C3c/C3 ratio and properdin levels increased with higher lobular inflammation scores as determined according to the Kleiner classification (C3c: p<0.01, C3c/C3 ratio: p<0.05, properdin: p<0.05. Hepatic mRNA expression of factor B and factor D did not differ between subjects with healthy livers and subjects with NASH (factor B: 1.00±0.19 vs. 0.71±0.07, p = 0.26; factor D: 1.00±0.21 vs. 0.66±0.14, p = 0.29;. Hepatic mRNA and protein levels of Decay Accelerating Factor tended to be increased in subjects with NASH (mRNA: 1.00±0.14 vs. 2.37±0.72; p = 0.22; protein: 0.51±0.11 vs. 1.97±0.67; p = 0.28. In contrast, factor H mRNA was downregulated in patients with NASH (1.00±0.09 vs. 0.71±0.06; p<0.05 and a similar trend was observed with hepatic protein levels (1.12±0.16 vs. 0.78±0.07; p = 0.08. Collectively, these data suggest a role for alternative

  13. Amino acids-incorporated nanoflowers with an intrinsic peroxidase-like activity

    Science.gov (United States)

    Wu, Zhuo-Fu; Wang, Zhi; Zhang, Ye; Ma, Ya-Li; He, Cheng-Yan; Li, Heng; Chen, Lei; Huo, Qi-Sheng; Wang, Lei; Li, Zheng-Qiang

    2016-03-01

    Functional molecules synthesized by self-assembly between inorganic salts and amino acids have attracted much attention in recent years. A simple method is reported here for fabricating hybrid organic–inorganic nanoflowers using copper (II) ions as the inorganic component and natural amino acids as the organic component. The results indicate that the interactions between amino acid and copper ions cause the growth of the nanoflowers composed by C, N, Cu, P and O elements. The Cu ions and Cu(AA)n complexes containing Cu-O bond are present in the nanoflowers. The nanoflowers have flower-like porous structure dominated by the R groups of amino acids with high surface-to-volume ratios, which is beneficial for exerting its peroxidase-like activity depending on Fenton-like reaction mechanism with ABTS and Rhodamine B as the substrates. It is expected that the nanoflowers hold great promise as enzyme mimics for application in the field of biosensor, bioanalysis and biocatalysis.

  14. Sculpting the Intrinsic Modular Organization of Spontaneous Brain Activity by Art.

    Science.gov (United States)

    Lin, Chia-Shu; Liu, Yong; Huang, Wei-Yuan; Lu, Chia-Feng; Teng, Shin; Ju, Tzong-Ching; He, Yong; Wu, Yu-Te; Jiang, Tianzi; Hsieh, Jen-Chuen

    2013-01-01

    Artistic training is a complex learning that requires the meticulous orchestration of sophisticated polysensory, motor, cognitive, and emotional elements of mental capacity to harvest an aesthetic creation. In this study, we investigated the architecture of the resting-state functional connectivity networks from professional painters, dancers and pianists. Using a graph-based network analysis, we focused on the art-related changes of modular organization and functional hubs in the resting-state functional connectivity network. We report that the brain architecture of artists consists of a hierarchical modular organization where art-unique and artistic form-specific brain states collectively mirror the mind states of virtuosos. We show that even in the resting state, this type of extraordinary and long-lasting training can macroscopically imprint a neural network system of spontaneous activity in which the related brain regions become functionally and topologically modularized in both domain-general and domain-specific manners. The attuned modularity reflects a resilient plasticity nurtured by long-term experience.

  15. Heterogeneous Effects of Direct Hypoxia Pathway Activation in Kidney Cancer.

    Directory of Open Access Journals (Sweden)

    Rafik Salama

    Full Text Available General activation of hypoxia-inducible factor (HIF pathways is classically associated with adverse prognosis in cancer and has been proposed to contribute to oncogenic drive. In clear cell renal carcinoma (CCRC HIF pathways are upregulated by inactivation of the von-Hippel-Lindau tumor suppressor. However HIF-1α and HIF-2α have contrasting effects on experimental tumor progression. To better understand this paradox we examined pan-genomic patterns of HIF DNA binding and associated gene expression in response to manipulation of HIF-1α and HIF-2α and related the findings to CCRC prognosis. Our findings reveal distinct pan-genomic organization of canonical and non-canonical HIF isoform-specific DNA binding at thousands of sites. Overall associations were observed between HIF-1α-specific binding, and genes associated with favorable prognosis and between HIF-2α-specific binding and adverse prognosis. However within each isoform-specific set, individual gene associations were heterogeneous in sign and magnitude, suggesting that activation of each HIF-α isoform contributes a highly complex mix of pro- and anti-tumorigenic effects.

  16. Activation and signaling of the p38 MAP kinase pathway

    Institute of Scientific and Technical Information of China (English)

    Tyler ZARUBIN; Jiahuai HAN

    2005-01-01

    The family members of the mitogen-activated protein (MAP) kinases mediate a wide variety of cellular behaviors in response to extracellular stimuli. One of the four main sub-groups, the p38 group of MAP kinases, serve as a nexus for signal transduction and play a vital role in numerous biological processes. In this review, we highlight the known characteristics and components of the p38 pathway along with the mechanism and consequences of p38 activation. We focus on the role of p38 as a signal transduction mediator and examine the evidence linking p38 to inflammation, cell cycle, cell death, development, cell differentiation, senescence and tumorigenesis in specific cell types. Upstream and downstream components of p38 are described and questions remaining to be answered are posed. Finally, we propose several directions for future research on p38.

  17. Energy-transducing H+-ATPase of Escherichia coli. Reconstitution of proton translocation activity of the intrinsic membrane sector.

    Science.gov (United States)

    Negrin, R S; Foster, D L; Fillingame, R H

    1980-06-25

    The intrinsic membrane sector (Fo) of the H+-ATPase complex of Escherichia coli has been purified, incorporated into liposomes, and its proton-translocating activity reconstituted. The Fo sector was prepared by treating a purified, particulate, F1FO-ATPase preparation with EDTA to solubilize the F1-ATPase. The resulting particulate Fo fraction was incorporated into liposomes of E. coli phospholipids by sonication. Proton efflux from these liposomes was measured with a pH electrode after imposition of a membrane potential. The kinetics of proton efflux fits that predicted by the Goldman-flux equation. The rate of proton efflux was increased maximally more than 100-fold on incorporation of the Fo sector into the liposomes. The rate of H+ efflux varied directly with the amount of Fo material added during reconstitution. Dicyclohexylcarbodiimide blocked Fo-mediated H+ efflux. Inhibition was shown to be due to reaction of dicyclohexylcarbodiimide with a specific proteolipid subunit of Fo. The preparation of Fo used in these studies contained the three proteins that had previously been identified as likely subunits of Fo (Foster, D. L., and Fillingame, R. H. (1979) J. Biol. Chem. 254, 8230-8236). It remains to be determined whether all three components are required for reconstitution of proton translocation activity.

  18. Intrinsic activation barriers and coadsorption effects for reactions on metal surfaces: unified formalism within the UBI-QEP approach

    Science.gov (United States)

    Sellers, Harrell; Shustorovich, Evgeny

    2002-04-01

    We present a unified formulation of the unity bond index-quadratic exponential potential method (UBI-QEP, formerly known as the BOC-MP method) of determining metal surface reaction energetics. We give a unified treatment of enthalpies and intrinsic activation barriers for dissociation and recombination reactions as particular cases of disproportionation reactions. We discuss numerous examples of elementary reactions, which form a database for various reaction mechanisms. We start with the zero coverage limit and then focus on coadsorption effects on reaction energetics on monometallic and bimetallic (alloy) surfaces. We consider first the full treatment and then develop the “uniform scaling” approximation, with guidelines (and examples) where it may be efficiently used. We provide tables of numerical values covering most of practically important cases of coadsorption effects on fcc(1 1 1) and fcc(1 0 0) surfaces, which allow one to easily estimate coverage effects on activation barriers by simple interpolation. We also clarify the nature of basic UBI-QEP parameters and correlation between local and global adsorbate coverage. These developments, illustrated by various examples, make applications of the UBI-QEP method much easier for practitioners, particularly those who have no UBI-model computer program and make calculations by hand.

  19. Albumin activates astrocytes and microglia through mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Ralay Ranaivo, Hantamalala; Wainwright, Mark S

    2010-02-08

    Following acute brain injury, albumin may gain access to the brain parenchyma. Clinical studies indicate a protective role for albumin in stroke but an increase in mortality associated with albumin administration following traumatic brain injury. We investigated the effects of albumin on astrocyte and microglial activation, and the role of mitogen-activated protein kinases (MAPK) in these responses. Albumin activated ERK1/2, p38 MAPK and JNK signaling pathways in astrocytes, and induced the production of interleukin (IL)-1beta, inducible nitric oxide (NO) synthase, the NO metabolite nitrite, and the chemokine CX3CL1 while reducing the level of S100B. The release of inflammatory markers by astrocytes was partially dependent on p38 MAPK and ERK1/2 pathways, but not JNK. In microglia, albumin exposure activated all three MAPK pathways and produced an increase in IL-1beta and nitrite. Inhibition of p38 MAPK in microglia leads to an increased level of IL1beta, while inhibition of all three MAPKs suppressed the release of nitrite. These results suggest that albumin activates astrocytes and microglia, inducing inflammatory responses involved both in the mechanisms of cellular injury and repair via activation of MAPK pathways, and thereby implicate glial activation in the clinical responses to administration of albumin.

  20. The glucagon-like peptide 1 receptor agonist enhances intrinsic peroxisome proliferator-activated receptor γ activity in endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Onuma, Hirohisa; Inukai, Kouichi, E-mail: kinukai@ks.kyorin-u.ac.jp; Kitahara, Atsuko; Moriya, Rie; Nishida, Susumu; Tanaka, Toshiaki; Katsuta, Hidenori; Takahashi, Kazuto; Sumitani, Yoshikazu; Hosaka, Toshio; Ishida, Hitoshi

    2014-08-22

    Highlights: • PPARγ activation was involved in the GLP-1-mediated anti-inflammatory action. • Exendin-4 enhanced endogenous PPARγ transcriptional activity in HUVECs. • H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement. • The anti-inflammatory effects of GLP-1 may be explained by PPARγ activation. - Abstract: Recent studies have suggested glucagon-like peptide-1 (GLP-1) signaling to exert anti-inflammatory effects on endothelial cells, although the precise underlying mechanism remains to be elucidated. In the present study, we investigated whether PPARγ activation is involved in the GLP-1-mediated anti-inflammatory action on endothelial cells. When we treated HUVEC cells with 0.2 ng/ml exendin-4, a GLP-1 receptor agonist, endogenous PPARγ transcriptional activity was significantly elevated, by approximately 20%, as compared with control cells. The maximum PPARγ activity enhancing effect of exendin-4 was observed 12 h after the initiation of incubation with exendin-4. As H89, a PKA inhibitor, abolished GLP-1-induced PPARγ enhancement, the signaling downstream from GLP-1 cross-talk must have been involved in PPARγ activation. In conclusion, our results suggest that GLP-1 has the potential to induce PPARγ activity, partially explaining the anti-inflammatory effects of GLP-1 on endothelial cells. Cross-talk between GLP-1 signaling and PPARγ activation would have major impacts on treatments for patients at high risk for cardiovascular disease.

  1. Corneal pain activates a trigemino-parabrachial pathway in rats.

    Science.gov (United States)

    Aicher, Sue A; Hegarty, Deborah M; Hermes, Sam M

    2014-03-06

    Corneal pain is mediated by primary afferent fibers projecting to the dorsal horn of the medulla, specifically the trigeminal nucleus caudalis. In contrast to reflex responses, the conscious perception of pain requires transmission of neural activity to higher brain centers. Ascending pain transmission is mediated primarily by pathways to either the thalamus or parabrachial nuclei. We previously showed that some corneal afferent fibers preferentially contact parabrachial-projecting neurons in the rostral pole of the trigeminal nucleus caudalis, but the role of these projection neurons in transmitting noxious information from the cornea has not been established. In the present study, we show that noxious stimulation of the corneal surface activates neurons in the rostral pole of the nucleus caudalis, including parabrachially projecting neurons that receive direct input from corneal afferent fibers. We used immunocytochemical detection of c-Fos protein as an index of neuronal activation after noxious ocular stimulation. Animals had previously received injections of a retrograde tracer into either thalamic or parabrachial nuclei to identify projection neurons in the trigeminal dorsal horn. Noxious stimulation of the cornea induced c-Fos in neurons sending projections to parabrachial nuclei, but not thalamic nuclei. We also confirmed that corneal afferent fibers identified with cholera toxin B preferentially target trigeminal dorsal horn neurons projecting to the parabrachial nucleus. The parabrachial region sends ascending projections to brain regions involved in emotional and homeostatic responses. Activation of the ascending parabrachial system may explain the extraordinary salience of stimulation of corneal nociceptors.

  2. Chimeric HIV-1 envelope glycoproteins with potent intrinsic granulocyte-macrophage colony-stimulating factor (GM-CSF activity.

    Directory of Open Access Journals (Sweden)

    Gözde Isik

    Full Text Available HIV-1 acquisition can be prevented by broadly neutralizing antibodies (BrNAbs that target the envelope glycoprotein complex (Env. An ideal vaccine should therefore be able to induce BrNAbs that can provide immunity over a prolonged period of time, but the low intrinsic immunogenicity of HIV-1 Env makes the elicitation of such BrNAbs challenging. Co-stimulatory molecules can increase the immunogenicity of Env and we have engineered a soluble chimeric Env trimer with an embedded granulocyte-macrophage colony-stimulating factor (GM-CSF domain. This chimeric molecule induced enhanced B and helper T cell responses in mice compared to Env without GM-CSF. We studied whether we could optimize the activity of the embedded GM-CSF as well as the antigenic structure of the Env component of the chimeric molecule. We assessed the effect of truncating GM-CSF, removing glycosylation-sites in GM-CSF, and adjusting the linker length between GM-CSF and Env. One of our designed Env(GM-CSF chimeras improved GM-CSF-dependent cell proliferation by 6-fold, reaching the same activity as soluble recombinant GM-CSF. In addition, we incorporated GM-CSF into a cleavable Env trimer and found that insertion of GM-CSF did not compromise Env cleavage, while Env cleavage did not compromise GM-CSF activity. Importantly, these optimized Env(GM-CSF proteins were able to differentiate human monocytes into cells with a macrophage-like phenotype. Chimeric Env(GM-CSF should be useful for improving humoral immunity against HIV-1 and these studies should inform the design of other chimeric proteins.

  3. Natural Optical Activity of Chiral Epoxides: the Influence of Structure and Environment on the Intrinsic Chiroptical Response

    Science.gov (United States)

    Lemler, Paul M.; Craft, Clayton L.; Vaccaro, Patrick

    2017-06-01

    Chiral epoxides built upon nominally rigid frameworks that incorporate aryl substituents have been shown to provide versatile backbones for asymmetric syntheses designed to generate novel pharmaceutical and catalytic agents. The ubiquity of these species has motivated the present studies of their intrinsic (solvent-free) circular birefringence (CB), the measurement of which serves as a benchmark for quantum-chemical predictions of non-resonant chiroptical behavior and as a beachhead for understanding the often-pronounced mediation of such properties by environmental perturbations (e.g., solvation). The optical rotatory dispersion (or wavelength-resolved CB) of (R)-styrene oxide (R-SO) and (S,S)-phenylpropylene oxide (S-PPO) have been interrogated under ambient solvated and isolated conditions, where the latter efforts exploited the ultrasensitive techniques of cavity ring-down polarimetry. Both of the targeted systems display marked solvation effects as evinced by changes the magnitude and (in the case of R-SO) the sign of the extracted specific optical rotation, with the anomalously large response evoked from S-PPO distinguishing it from other members of the epoxide family. Linear-response calculations of dispersive optical activity have been performed at both density-functional and coupled-cluster levels of theory to unravel the structural and electronic origins of experimental findings, thereby suggesting the possible involvement of hindered torsional motion along dihedral coordinates adjoining phenyl and epoxide moieties.

  4. Near-infrared photocatalytic activity induced by intrinsic defects in Bi2MO6 (M = W, Mo).

    Science.gov (United States)

    Jing, Tao; Dai, Ying; Wei, Wei; Ma, Xiangchao; Huang, Baibiao

    2014-09-14

    The electronic structure and related photocatalytic properties of Bi2MO6 (M = W, Mo) with various intrinsic defects are studied based on the first-principles density functional theory (DFT). Our results indicate that O vacancies form easily in both Bi2WO6 and Bi2MoO6 under Bi rich/O poor conditions. The near-infrared light transitions can be realized involving electrons from the O vacancy induced impurity states within the band gap to the conduction band. Rather than acting as photogenerated carrier recombination centers, the impurity states caused by O vacancies favor the transfer of photogenerated holes and further benefit the photocatalytic process due to the delocalized nature. The spatial separation of photogenerated carriers among different layers can be realized, which reduces the carrier recombination and improves the photocatalytic activity. In addition, Bi2WO6 with O vacancies is desirable for having better near-infrared photocatalytic performance than Bi2MoO6 due to the larger mobility of photogenerated holes.

  5. Intrinsic Motivation and Engagement as "Active Ingredients" in Garden-Based Education: Examining Models and Measures Derived from Self-Determination Theory

    Science.gov (United States)

    Skinner, Ellen A.; Chi, Una

    2012-01-01

    Building on self-determination theory, this study presents a model of intrinsic motivation and engagement as "active ingredients" in garden-based education. The model was used to create reliable and valid measures of key constructs, and to guide the empirical exploration of motivational processes in garden-based learning. Teacher- and…

  6. Early Years Education: Are Young Students Intrinsically or Extrinsically Motivated Towards School Activities? A Discussion about the Effects of Rewards on Young Children's Learning

    Science.gov (United States)

    Theodotou, Evgenia

    2014-01-01

    Rewards can reinforce and at the same time forestall young children's willingness to learn. However, they are broadly used in the field of education, especially in early years settings, to stimulate children towards learning activities. This paper reviews the theoretical and research literature related to intrinsic and extrinsic motivational…

  7. Axon Regeneration Is Regulated by Ets–C/EBP Transcription Complexes Generated by Activation of the cAMP/Ca2+ Signaling Pathways

    Science.gov (United States)

    Matsumoto, Kunihiro

    2015-01-01

    The ability of specific neurons to regenerate their axons after injury is governed by cell-intrinsic regeneration pathways. In Caenorhabditis elegans, the JNK and p38 MAPK pathways are important for axon regeneration. Axonal injury induces expression of the svh-2 gene encoding a receptor tyrosine kinase, stimulation of which by the SVH-1 growth factor leads to activation of the JNK pathway. Here, we identify ETS-4 and CEBP-1, related to mammalian Ets and C/EBP, respectively, as transcriptional activators of svh-2 expression following axon injury. ETS-4 and CEBP-1 function downstream of the cAMP and Ca2+–p38 MAPK pathways, respectively. We show that PKA-dependent phosphorylation of ETS-4 promotes its complex formation with CEBP-1. Furthermore, activation of both cAMP and Ca2+ signaling is required for activation of svh-2 expression. Thus, the cAMP/Ca2+ signaling pathways cooperatively activate the JNK pathway, which then promotes axon regeneration. PMID:26484536

  8. Axon Regeneration Is Regulated by Ets-C/EBP Transcription Complexes Generated by Activation of the cAMP/Ca2+ Signaling Pathways.

    Directory of Open Access Journals (Sweden)

    Chun Li

    2015-10-01

    Full Text Available The ability of specific neurons to regenerate their axons after injury is governed by cell-intrinsic regeneration pathways. In Caenorhabditis elegans, the JNK and p38 MAPK pathways are important for axon regeneration. Axonal injury induces expression of the svh-2 gene encoding a receptor tyrosine kinase, stimulation of which by the SVH-1 growth factor leads to activation of the JNK pathway. Here, we identify ETS-4 and CEBP-1, related to mammalian Ets and C/EBP, respectively, as transcriptional activators of svh-2 expression following axon injury. ETS-4 and CEBP-1 function downstream of the cAMP and Ca2+-p38 MAPK pathways, respectively. We show that PKA-dependent phosphorylation of ETS-4 promotes its complex formation with CEBP-1. Furthermore, activation of both cAMP and Ca2+ signaling is required for activation of svh-2 expression. Thus, the cAMP/Ca2+ signaling pathways cooperatively activate the JNK pathway, which then promotes axon regeneration.

  9. Axon Regeneration Is Regulated by Ets-C/EBP Transcription Complexes Generated by Activation of the cAMP/Ca2+ Signaling Pathways.

    Science.gov (United States)

    Li, Chun; Hisamoto, Naoki; Matsumoto, Kunihiro

    2015-10-01

    The ability of specific neurons to regenerate their axons after injury is governed by cell-intrinsic regeneration pathways. In Caenorhabditis elegans, the JNK and p38 MAPK pathways are important for axon regeneration. Axonal injury induces expression of the svh-2 gene encoding a receptor tyrosine kinase, stimulation of which by the SVH-1 growth factor leads to activation of the JNK pathway. Here, we identify ETS-4 and CEBP-1, related to mammalian Ets and C/EBP, respectively, as transcriptional activators of svh-2 expression following axon injury. ETS-4 and CEBP-1 function downstream of the cAMP and Ca2+-p38 MAPK pathways, respectively. We show that PKA-dependent phosphorylation of ETS-4 promotes its complex formation with CEBP-1. Furthermore, activation of both cAMP and Ca2+ signaling is required for activation of svh-2 expression. Thus, the cAMP/Ca2+ signaling pathways cooperatively activate the JNK pathway, which then promotes axon regeneration.

  10. Serotonin activates overall feeding by activating two separate neural pathways in Caenorhabditis elegans.

    Science.gov (United States)

    Song, Bo-mi; Avery, Leon

    2012-02-08

    Food intake in the nematode Caenorhabditis elegans requires two distinct feeding motions, pharyngeal pumping and isthmus peristalsis. Bacteria, the natural food of C. elegans, activate both feeding motions (Croll, 1978; Horvitz et al., 1982; Chiang et al., 2006). The mechanisms by which bacteria activate the feeding motions are largely unknown. To understand the process, we studied how serotonin, an endogenous pharyngeal pumping activator whose action is triggered by bacteria, activates feeding motions. Here, we show that serotonin, like bacteria, activates overall feeding by activating isthmus peristalsis as well as pharyngeal pumping. During active feeding, the frequencies and the timing of onset of the two motions were distinct, but each isthmus peristalsis was coupled to the preceding pump. We found that serotonin activates the two feeding motions mainly by activating two separate neural pathways in response to bacteria. For activating pumping, the SER-7 serotonin receptor in the MC motor neurons in the feeding organ activated cholinergic transmission from MC to the pharyngeal muscles by activating the Gsα signaling pathway. For activating isthmus peristalsis, SER-7 in the M4 (and possibly M2) motor neuron in the feeding organ activated the G(12)α signaling pathway in a cell-autonomous manner, which presumably activates neurotransmission from M4 to the pharyngeal muscles. Based on our results and previous calcium imaging of pharyngeal muscles (Shimozono et al., 2004), we propose a model that explains how the two feeding motions are separately regulated yet coupled. The feeding organ may have evolved this way to support efficient feeding.

  11. Mouse cytotoxic T cell-derived granzyme B activates the mitochondrial cell death pathway in a Bim-dependent fashion.

    Science.gov (United States)

    Catalán, Elena; Jaime-Sánchez, Paula; Aguiló, Nacho; Simon, Markus M; Froelich, Christopher J; Pardo, Julián

    2015-03-13

    Cytotoxic T cells (Tc) use perforin and granzyme B (gzmB) to kill virus-infected cells and cancer cells. Recent evidence suggests that human gzmB primarily induces apoptosis via the intrinsic mitochondrial pathway by either cleaving Bid or activating Bim leading to the activation of Bak/Bax and subsequent generation of active caspase-3. In contrast, mouse gzmB is thought to predominantly induce apoptosis by directly processing pro-caspase-3. However, in certain mouse cell types gzmB-mediated apoptosis mainly occurs via the mitochondrial pathway. To investigate whether Bim is involved under the latter conditions, we have now employed ex vivo virus-immune mouse Tc that selectively kill by using perforin and gzmB (gzmB(+)Tc) as effector cells and wild type as well as Bim- or Bak/Bax-deficient spontaneously (3T9) or virus-(SV40) transformed mouse embryonic fibroblast cells as targets. We show that gzmB(+)Tc-mediated apoptosis (phosphatidylserine translocation, mitochondrial depolarization, cytochrome c release, and caspase-3 activation) was severely reduced in 3T9 cells lacking either Bim or both Bak and Bax. This outcome was related to the ability of Tc cells to induce the degradation of Mcl-1 and Bcl-XL, the anti-apoptotic counterparts of Bim. In contrast, gzmB(+)Tc-mediated apoptosis was not affected in SV40-transformed mouse embryonic fibroblast cells lacking Bak/Bax. The data provide evidence that Bim participates in mouse gzmB(+)Tc-mediated apoptosis of certain targets by activating the mitochondrial pathway and suggest that the mode of cell death depends on the target cell. Our results suggest that the various molecular events leading to transformation and/or immortalization of cells have an impact on their relative resistance to the multiple gzmB(+)Tc-induced death pathways.

  12. Collectin-11/MASP complex formation triggers activation of the lectin complement pathway--the fifth lectin pathway initiation complex

    DEFF Research Database (Denmark)

    Ma, Ying Jie; Skjoedt, Mikkel-Ole; Garred, Peter

    2013-01-01

    complement pathway regulator MAP-1. Furthermore, we found that complex formation between recombinant collectin-11 and recombinant MASP-2 on Candida albicans leads to deposition of C4b. Native collectin-11 in serum mediated complement activation and deposition of C4b and C3b, and formation of the terminal...... complement complex on C. albicans. Moreover, spiking collectin-11-depleted serum, which did not mediate complement activation, with recombinant collectin-11 restored the complement activation capability. These results define collectin-11 as the fifth recognition molecule in the lectin complement pathway...

  13. An Efficient Method to Identify Conditionally Activated Transcription Factors and their Corresponding Signal Transduction Pathway Segments

    Directory of Open Access Journals (Sweden)

    Haiyan Hu

    2009-11-01

    Full Text Available A signal transduction pathway (STP is a cascade composed of a series of signal transferring steps, which often activate one or more transcription factors (TFs to control the transcription of target genes. Understanding signaling pathways is important to our understanding of the molecular mechanisms of disease. Many condition-annotated pathways have been deposited in public databases. However, condition-annotated pathways are far from complete, considering the large number of possible conditions. Computational methods to assist in the identification of conditionally activated pathways are greatly needed. In this paper, we propose an efficient method to identify conditionally activated pathway segments starting from the identification of conditionally activated TFs, by incorporating protein-DNA binding data, gene expression data and protein interaction data. Applying our methods on several microarray datasets, we have discovered many significantly activated TFs and their corresponding pathway segments, which are supported by evidence in the literature.

  14. DART: Denoising Algorithm based on Relevance network Topology improves molecular pathway activity inference

    Directory of Open Access Journals (Sweden)

    Purushotham Arnie

    2011-10-01

    Full Text Available Abstract Background Inferring molecular pathway activity is an important step towards reducing the complexity of genomic data, understanding the heterogeneity in clinical outcome, and obtaining molecular correlates of cancer imaging traits. Increasingly, approaches towards pathway activity inference combine molecular profiles (e.g gene or protein expression with independent and highly curated structural interaction data (e.g protein interaction networks or more generally with prior knowledge pathway databases. However, it is unclear how best to use the pathway knowledge information in the context of molecular profiles of any given study. Results We present an algorithm called DART (Denoising Algorithm based on Relevance network Topology which filters out noise before estimating pathway activity. Using simulated and real multidimensional cancer genomic data and by comparing DART to other algorithms which do not assess the relevance of the prior pathway information, we here demonstrate that substantial improvement in pathway activity predictions can be made if prior pathway information is denoised before predictions are made. We also show that genes encoding hubs in expression correlation networks represent more reliable markers of pathway activity. Using the Netpath resource of signalling pathways in the context of breast cancer gene expression data we further demonstrate that DART leads to more robust inferences about pathway activity correlations. Finally, we show that DART identifies a hypothesized association between oestrogen signalling and mammographic density in ER+ breast cancer. Conclusions Evaluating the consistency of prior information of pathway databases in molecular tumour profiles may substantially improve the subsequent inference of pathway activity in clinical tumour specimens. This de-noising strategy should be incorporated in approaches which attempt to infer pathway activity from prior pathway models.

  15. Spontaneous oscillatory activity in rd1 mouse retina is transferred from ON pathway to OFF pathway via glycinergic synapse.

    Science.gov (United States)

    Poria, Deepak; Dhingra, Narender K

    2015-01-15

    Retinal ganglion cells (RGCs) spike randomly in the dark and carry information about visual stimuli to the brain via specific spike patterns. However, following photoreceptor loss, both ON and OFF type of RGCs exhibit spontaneous oscillatory spike activity, which reduces the quality of information they can carry. Furthermore, it is not clear how the oscillatory activity would interact with the experimental treatment approaches designed to produce artificial vision. The oscillatory activity is considered to originate in ON-cone bipolar cells, AII amacrine cells, and/or their synaptic interactions. However, it is unknown how the oscillatory activity is generated in OFF RGCs. We tested the hypothesis that oscillatory activity is transferred from the ON pathway to the OFF pathway via the glycinergic AII amacrine cells. Using extracellular loose-patch and whole cell patch recordings, we recorded oscillatory activity in ON and OFF RGCs and studied their response to strychnine, a specific glycine receptor blocker. The cells were labeled with a fluorescent dye, and their dendritic stratification in inner plexiform layer was studied using confocal microscopy. Application of strychnine resulted in abolition of the oscillatory burst activity in OFF RGCs but not in ON RGCs, implying that oscillatory activity is generated in ON pathway and is transferred to OFF pathway, likely via the glycinergic AII amacrine cells. We found oscillatory activity in RGCs as early as postnatal day 12 in rd1 mouse, when rod degeneration has started but cones are still intact. This suggests that the oscillatory activity in rd1 mouse retina originates in rod pathway.

  16. IL-17/Th17 pathway is activated in acne lesions.

    Directory of Open Access Journals (Sweden)

    Hanna-Leena Kelhälä

    Full Text Available The mechanisms of inflammation in acne are currently subject of intense investigation. This study focused on the activation of adaptive and innate immunity in clinically early visible inflamed acne lesions and was performed in two independent patient populations. Biopsies were collected from lesional and non-lesional skin of acne patients. Using Affymetrix Genechips, we observed significant elevation of the signature cytokines of the Th17 lineage in acne lesions compared to non-lesional skin. The increased expression of IL-17 was confirmed at the RNA and also protein level with real-time PCR (RT-PCR and Luminex technology. Cytokines involved in Th17 lineage differentiation (IL-1β, IL-6, TGF-β, IL23p19 were remarkably induced at the RNA level. In addition, proinflammatory cytokines and chemokines (TNF-α, IL-8, CSF2 and CCL20, Th1 markers (IL12p40, CXCR3, T-bet, IFN-γ, T regulatory cell markers (Foxp3, IL-10, TGF-β and IL-17 related antimicrobial peptides (S100A7, S100A9, lipocalin, hBD2, hBD3, hCAP18 were induced. Importantly, immunohistochemistry revealed significantly increased numbers of IL-17A positive T cells and CD83 dendritic cells in the acne lesions. In summary our results demonstrate the presence of IL-17A positive T cells and the activation of Th17-related cytokines in acne lesions, indicating that the Th17 pathway is activated and may play a pivotal role in the disease process, possibly offering new targets of therapy.

  17. Imatinib Reverses Doxorubicin Resistance by Affecting Activation of STAT3-Dependent NF-κB and HSP27/p38/AKT Pathways and by Inhibiting ABCB1

    Science.gov (United States)

    Sims, Jonathan T.; Ganguly, Sourik S.; Bennett, Holly; Friend, J. Woodrow; Tepe, Jessica; Plattner, Rina

    2013-01-01

    Despite advances in cancer detection and prevention, a diagnosis of metastatic disease remains a death sentence due to the fact that many cancers are either resistant to chemotherapy (conventional or targeted) or develop resistance during treatment, and residual chemoresistant cells are highly metastatic. Metastatic cancer cells resist the effects of chemotherapeutic agents by upregulating drug transporters, which efflux the drugs, and by activating proliferation and survival signaling pathways. Previously, we found that c-Abl and Arg non-receptor tyrosine kinases are activated in breast cancer, melanoma, and glioblastoma cells, and promote cancer progression. In this report, we demonstrate that the c-Abl/Arg inhibitor, imatinib (imatinib mesylate, STI571, Gleevec), reverses intrinsic and acquired resistance to the anthracycline, doxorubicin, by inducing G2/M arrest and promoting apoptosis in cancer cells expressing highly active c-Abl and Arg. Significantly, imatinib prevents intrinsic resistance by promoting doxorubicin-mediated NF-κB/p65 nuclear localization and repression of NF-κB targets in a STAT3-dependent manner, and by preventing activation of a novel STAT3/HSP27/p38/Akt survival pathway. In contrast, imatinib prevents acquired resistance by inhibiting upregulation of the ABC drug transporter, ABCB1, directly inhibiting ABCB1 function, and abrogating survival signaling. Thus, imatinib inhibits multiple novel chemoresistance pathways, which indicates that it may be effective in reversing intrinsic and acquired resistance in cancers containing highly active c-Abl and Arg, a critical step in effectively treating metastatic disease. Furthermore, since imatinib converts a master survival regulator, NF-κB, from a pro-survival into a pro-apoptotic factor, our data suggest that NF-κB inhibitors may be ineffective in sensitizing tumors containing activated c-Abl/Arg to anthracyclines, and instead might antagonize anthracycline-induced apoptosis. PMID:23383209

  18. Increased activity of the mannan-binding lectin complement activation pathway in patients with colorectal cancer

    DEFF Research Database (Denmark)

    Ytting, H; Jensenius, Jens Christian; Christensen, I J

    2004-01-01

    in the colon or rectum, and disease stages according to Dukes' classification. No statistical difference (P=0.20) in frequency of MBL deficiency was found between the patients (20%) and the donors (27%). CONCLUSIONS: Overall, the MBL complement activation pathway is significantly increased in patients......BACKGROUND: Postoperative bacterial infectious complications are frequent in patients with colorectal cancer (CRC), with subsequent increased recurrence rates and poor prognosis. Deficiency of the mannan-binding lectin (MBL) complement activation pathway may cause increased risk of infection......: Serum MBL concentrations and MBL/MASP activity were determined using immunofluorometric assays. The levels are presented as the median, inter-quartile range and range. RESULTS: Serum MBL levels were significantly (P

  19. Pituitary adenylate cyclase-activating polypeptide (PACAP) inhibits the slow afterhyperpolarizing current sIAHP in CA1 pyramidal neurons by activating multiple signaling pathways

    Science.gov (United States)

    Taylor, Ruth DT; Madsen, Marita Grønning; Krause, Michael; Sampedro-Castañeda, Marisol; Stocker, Martin; Pedarzani, Paola

    2014-01-01

    The slow afterhyperpolarizing current (sIAHP) is a calcium-dependent potassium current that underlies the late phase of spike frequency adaptation in hippocampal and neocortical neurons. sIAHP is a well-known target of modulation by several neurotransmitters acting via the cyclic AMP (cAMP) and protein kinase A (PKA)-dependent pathway. The neuropeptide pituitary adenylate cyclase activating peptide (PACAP) and its receptors are present in the hippocampal formation. In this study we have investigated the effect of PACAP on the sIAHP and the signal transduction pathway used to modulate intrinsic excitability of hippocampal pyramidal neurons. We show that PACAP inhibits the sIAHP, resulting in a decrease of spike frequency adaptation, in rat CA1 pyramidal cells. The suppression of sIAHP by PACAP is mediated by PAC1 and VPAC1 receptors. Inhibition of PKA reduced the effect of PACAP on sIAHP, suggesting that PACAP exerts part of its inhibitory effect on sIAHP by increasing cAMP and activating PKA. The suppression of sIAHP by PACAP was also strongly hindered by the inhibition of p38 MAP kinase (p38 MAPK). Concomitant inhibition of PKA and p38 MAPK indicates that these two kinases act in a sequential manner in the same pathway leading to the suppression of sIAHP. Conversely, protein kinase C is not part of the signal transduction pathway used by PACAP to inhibit sIAHP in CA1 neurons. Our results show that PACAP enhances the excitability of CA1 pyramidal neurons by inhibiting the sIAHP through the activation of multiple signaling pathways, most prominently cAMP/PKA and p38 MAPK. Our findings disclose a novel modulatory action of p38 MAPK on intrinsic excitability and the sIAHP, underscoring the role of this current as a neuromodulatory hub regulated by multiple protein kinases in cortical neurons. © 2013 The Authors. Hippocampus Published by Wiley Periodicals, Inc. PMID:23996525

  20. 教师专业自主发展:内涵、意义及内在路径%The Connotation,Significance and Intrinsic Pathway Concerning Teachers' Self-directed Professional Development

    Institute of Scientific and Technical Information of China (English)

    刘黎明

    2012-01-01

    Teachers' professional development means that the teachers have self-developmental sense and ability,which include subjective consciousness,development awareness,and innovation sense.It also calls for teachers to bear the responsibilities of professional development actively and consciously.It means that the teachers can improve their educational ability and achieve their self-development featuring plurality,diversity,and creativity through their incessant study,practice,reflection,criticism,and innovation.The significance of this lies in the fact that it can promote teachers' initiative and creativity,students' autonomic learning and development,and increase teachers' sense of happiness.The intrinsic pathway to help realize teachers' professional development is to promote education professional spirit of teachers.It also helps if the teachers can improve themselves through self-reflection and research,cooperation and mutual aid.In order to realize the goal,teachers should keep reading to practise life-long learning.%教师的专业自主发展是指教师具有自我发展的意识和能力,包括主体意识、发展意识、创新意识和能力,能够主动地自觉地承担专业发展的主要责任,通过不断地学习、实践、反思、批判、创新,提升自己的教育教学能力,从而实现发展的多元性、差异性和创造性。它的意义在于:促进教师生活的主动性和创造性;促进学生自主学习和成长;提升教师的幸福感。实现教师的专业自主发展的内在路径是:提升教育专业精神;在自我反思和研究中成长;在合作、互动中成长;终身学习:教师的阅读。

  1. Cisplatin induces cytotoxicity through the mitogen-activated protein kinase pathways and activating transcription factor 3.

    Science.gov (United States)

    St Germain, Carly; Niknejad, Nima; Ma, Laurie; Garbuio, Kyla; Hai, Tsonwin; Dimitroulakos, Jim

    2010-07-01

    The mechanisms underlying the proapoptotic effect of the chemotherapeutic agent, cisplatin, are largely undefined. Understanding the mechanisms regulating cisplatin cytotoxicity may uncover strategies to enhance the efficacy of this important therapeutic agent. This study evaluates the role of activating transcription factor 3 (ATF3) as a mediator of cisplatin-induced cytotoxicity. Cytotoxic doses of cisplatin and carboplatin treatments consistently induced ATF3 expression in five tumor-derived cell lines. Characterization of this induction revealed a p53, BRCA1, and integrated stress response-independent mechanism, all previously implicated in stress-mediated ATF3 induction. Analysis of mitogen-activated protein kinase (MAPK) pathway involvement in ATF3 induction by cisplatin revealed a MAPK-dependent mechanism. Cisplatin treatment combined with specific inhibitors to each MAPK pathway (c-Jun N-terminal kinase, extracellular signal-regulated kinase, and p38) resulted in decreased ATF3 induction at the protein level. MAPK pathway inhibition led to decreased ATF3 messenger RNA expression and reduced cytotoxic effects of cisplatin as measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assay. In A549 lung carcinoma cells, targeting ATF3 with specific small hairpin RNA also attenuated the cytotoxic effects of cisplatin. Similarly, ATF3-/- murine embryonic fibroblasts (MEFs) were shown to be less sensitive to cisplatin-induced cytotoxicity compared with ATF3+/+ MEFs. This study identifies cisplatin as a MAPK pathway-dependent inducer of ATF3, whose expression influences cisplatin's cytotoxic effects.

  2. Signal transduction pathways in liver and the influence of hepatitis C virus infection on their activities

    Institute of Scientific and Technical Information of China (English)

    Magdalena M Dabrowska; Anatol Panasiuk; Robert Flisiak

    2009-01-01

    In liver, the most intensively studied transmembrane and intracellular signal transduction pathways are the Janus kinase signal transduction pathway, the mitogen-activated protein kinases signal transduction pathway, the transforming growth factor b signal transduction pathway, the tumor necrosis factor a signal transduction pathway and the recently discovered sphingolipid signal transduction pathway. All of them are activated by many different cytokines and growth factors. They regulate specific cell mechanisms such as hepatocytes proliferation, growth, differentiation, adhesion, apoptosis, and synthesis and degradation of the extracellular matrix. The replication cycle of hepatitis C virus (HCV) is intracellular and requires signal transduction to the nucleus to regulate transcription of its genes. Moreover, HCV itself, by its structural and nonstructural proteins, could influence the activity of the second signal messengers. Thus, the inhibition of the transmembrane and intracellular signal transduction pathways could be a new therapeutic target in chronic hepatitis C treatment.

  3. When 'fit' leads to fit, and when 'fit' leads to fat: how message framing and intrinsic vs. extrinsic exercise outcomes interact in promoting physical activity.

    Science.gov (United States)

    Gallagher, Kristel M; Updegraff, John A

    2011-07-01

    A unique aspect of exercise is that people may choose to engage in it to achieve a variety of outcomes, ranging from extrinsic (appearance, health) to intrinsic (satisfaction, enjoyment). We examined how the impact of gain- vs. loss-framed messages depends on the type of outcome emphasised. Drawing from regulatory focus theory (Higgins, E.T. (1997). Beyond pleasure and pain. American Psychologist, 52, 1280-1300; Higgins, E.T. (2000). Making a good decision: Value from fit. American Psychologist, 55, 1217-1230), we predicted that gain-framed messages would 'fit' with intrinsic outcomes and loss-framed messages would 'fit' with extrinsic outcomes, but the effect of such fit on physical activity would depend on the participants' need for cognition (NC). We tested these hypotheses with a sample of 176 sedentary young adults who read an exercise message with randomly assigned frame (gain/loss) and outcome (intrinsic/extrinsic). Participants provided daily reports of exercise over the following week. The predicted interaction between frame, outcome and NC was found (p=0.001) such that a 'fit' message promoted somewhat, but not significantly, greater exercise for those with high NC, but a 'non-fit' message promoted significantly greater exercise for those with low NC. Furthermore, differences in physical activity were partially mediated by attitudes towards exercise. Findings shed light on how the outcomes and motivations associated with physical activity shape people's behavioural responses to framed health communications. © 2011 Taylor & Francis

  4. Metabolic pathways in immune cell activation and quiescence.

    Science.gov (United States)

    Pearce, Erika L; Pearce, Edward J

    2013-04-18

    Studies of immune system metabolism ("immunometabolism") segregate along two paths. The first investigates the effects of immune cells on organs that regulate whole-body metabolism, such as adipose tissue and liver. The second explores the role of metabolic pathways within immune cells and how this regulates immune response outcome. Distinct metabolic pathways diverge and converge at many levels, and, therefore, cells face choices as to how to achieve their metabolic goals. There is interest in fully understanding how and why immune cells commit to particular metabolic fates and in elucidating the immunologic consequences of reaching a metabolic endpoint by one pathway versus another. This is particularly intriguing, given that metabolic commitment is influenced not only by substrate availability but also by signaling pathways elicited by metabolites. Thus, metabolic choices in cells enforce fate and function, and this area will be the subject of this review. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. An assay for the mannan-binding lectin pathway of complement activation

    DEFF Research Database (Denmark)

    Petersen, Steen Vang; Thiel, S; Jensen, L;

    2001-01-01

    The mannan-binding lectin (MBL) pathway of complement activation has been established as the third pathway of complement activation. MBL is a carbohydrate-binding serum protein, which circulates in complex with serine proteases known as mannan-binding lectin associated serine proteases (MASPs...... activation. Therefore, in a generally applicable complement activation assay specific for the MBL pathway, the activity of the classical pathway must be inhibited. This can be accomplished by exploiting the finding that high ionic strength buffers inhibit the binding of C1q to immune complexes and disrupt...... the C1 complex, whereas the carbohydrate-binding activity of MBL and the integrity of the MBL complex is maintained under hypertonic conditions. In the assay described here, the specific C4b-depositing capacity of the MBL pathway was determined by incubating serum diluted in buffer containing 1 M Na...

  6. Dichloromethane fraction of Melissa officinalis induces apoptosis by activation of intrinsic and extrinsic pathways in human leukemia cell lines.

    Science.gov (United States)

    Ebrahimnezhad Darzi, Salimeh; Amirghofran, Zahra

    2013-06-01

    Various components from medicinal plants are currently used in cancer therapy because of their apoptosis-inducing effects. The present study has aimed to investigate the growth inhibitory and apoptotic effects of Melissa officinalis on tumor cells. We prepared different fractions of this plant to investigate their inhibitory effects on two leukemia cell lines, Jurkat and K562. Fractions with the highest inhibitory effects were examined for induction of apoptosis by the annexin V/propidium iodide assay and cell cycle changes by flow cytometry. Real-time polymerase chain reaction evaluated the changes in expression of apoptosis-related genes. Among different fractions, dichloromethane and n-hexane dose-dependent showed the strongest inhibitory effects on both K562 and Jurkat cells. The dichloromethane fraction significantly induced apoptosis at concentration of 50 µg/ml on Jurkat (85.66 ± 4.9%) and K562 cells (65.04 ± 0.93%) at 24 h after treatment (p officinalis had the ability to induce apoptosis and change apoptosis-related gene expression in leukemia cells.

  7. Activation of the intrinsic cell death pathway, increased apoptosis and modulation of astrocytes in the cerebellum of diabetic rats.

    Science.gov (United States)

    Lechuga-Sancho, Alfonso M; Arroba, Ana I; Frago, Laura M; Pañeda, Covadonga; García-Cáceres, Cristina; Delgado Rubín de Célix, Arancha; Argente, Jesús; Chowen, Julie A

    2006-08-01

    Poorly controlled diabetes mellitus results in structural and functional changes in many brain regions. We demonstrate that in streptozotocin-induced diabetic rats cell death is increased and proliferation decreased in the cerebellum, indicating overall cell loss. Levels of both the proform and cleaved forms of caspases 3, 6 and 9 are increased, with no change in caspases 7, 8 or 12. Colocalization of glial fibrillary acidic protein (GFAP) and cleaved caspase 3 and GFAP in TUNEL-positive cells increased in diabetic rats. Changes in GFAP levels paralleled modifications in proliferating cell nuclear antigen (PCNA), increasing at 1 week of diabetes and decreasing thereafter, and proliferating GFAP-positive cells were decreased in the cerebellum of diabetic rats. These results suggest that astrocytes are dramatically affected in the cerebellum, including an increase in cell death and a decrease in proliferation, and this could play a role in the structural and functional changes in this brain area in diabetes.

  8. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC.

    Science.gov (United States)

    Occhi, Gianluca; Barollo, Susi; Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-10-13

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice.

  9. A constitutive active MAPK/ERK pathway due to BRAFV600E positively regulates AHR pathway in PTC

    Science.gov (United States)

    Regazzo, Daniela; Bertazza, Loris; Galuppini, Francesca; Guzzardo, Vincenza; Jaffrain-Rea, Marie Lise; Vianello, Federica; Ciato, Denis; Ceccato, Filippo; Watutantrige-Fernando, Sara; Bisognin, Andrea; Bortoluzzi, Stefania; Pennelli, Gianmaria; Boscaro, Marco; Scaroni, Carla; Mian, Caterina

    2015-01-01

    The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor mediating the toxicity and tumor-promoting properties of dioxin. AHR has been reported to be overexpressed and constitutively active in a variety of solid tumors, but few data are currently available concerning its role in thyroid cancer. In this study we quantitatively explored a series of 51 paired-normal and papillary thyroid carcinoma (PTC) tissues for AHR-related genes. We identified an increased AHR expression/activity in PTC, independently from its nuclear dimerization partner and repressor but strictly related to a constitutive active MAPK/ERK pathway. The AHR up-regulation followed by an increased expression of AHR target genes was confirmed by a meta-analysis of published microarray data, suggesting a ligand-independent active AHR pathway in PTC. In-vitro studies using a PTC-derived cell line (BCPAP) and HEK293 cells showed that BRAFV600E may directly modulate AHR localization, induce AHR expression and activity in an exogenous ligand-independent manner. The AHR pathway might represent a potential novel therapeutic target for PTC in the clinical practice. PMID:26392334

  10. Using a combination of fMRI and anterior temporal lobe rTMS to measure intrinsic and induced activation changes across the semantic cognition network

    Science.gov (United States)

    Binney, Richard J.; Lambon Ralph, Matthew A.

    2015-01-01

    By developing and applying a method which combines fMRI and rTMS to explore semantic cognition, we identified both intrinsic (related to automatic changes in task/stimulus-related processing) and induced (i.e., associated with the effect of TMS) activation changes in the core, functionally-coupled network elements. Low-frequency rTMS applied to the human anterior temporal lobe (ATL) induced: (a) a local suppression at the site of stimulation; (b) remote suppression in three other ipsilateral semantic regions; and (c) a compensatory up-regulation in the contralateral ATL. Further examination of activity over time revealed that the compensatory changes appear to be a modulation of intrinsic variations that occur within the unperturbed network. As well as providing insights into the dynamic collaboration between core regions, the ability to observe intrinsic and induced changes in vivo may provide an important opportunity to understand the key mechanisms that underpin recovery of function in neurological patient groups. PMID:25448851

  11. Lutetium oxyorthosilicate (LSO) intrinsic activity correction and minimal detectable target activity study for SPECT imaging with a LSO-based animal PET scanner

    Science.gov (United States)

    Yao, Rutao; Ma, Tianyu; Shao, Yiping

    2008-08-01

    This work is part of a feasibility study to develop SPECT imaging capability on a lutetium oxyorthosilicate (LSO) based animal PET system. The SPECT acquisition was enabled by inserting a collimator assembly inside the detector ring and acquiring data in singles mode. The same LSO detectors were used for both PET and SPECT imaging. The intrinsic radioactivity of 176Lu in the LSO crystals, however, contaminates the SPECT data, and can generate image artifacts and introduce quantification error. The objectives of this study were to evaluate the effectiveness of a LSO background subtraction method, and to estimate the minimal detectable target activity (MDTA) of image object for SPECT imaging. For LSO background correction, the LSO contribution in an image study was estimated based on a pre-measured long LSO background scan and subtracted prior to the image reconstruction. The MDTA was estimated in two ways. The empirical MDTA (eMDTA) was estimated from screening the tomographic images at different activity levels. The calculated MDTA (cMDTA) was estimated from using a formula based on applying a modified Currie equation on an average projection dataset. Two simulated and two experimental phantoms with different object activity distributions and levels were used in this study. The results showed that LSO background adds concentric ring artifacts to the reconstructed image, and the simple subtraction method can effectively remove these artifacts—the effect of the correction was more visible when the object activity level was near or above the eMDTA. For the four phantoms studied, the cMDTA was consistently about five times of the corresponding eMDTA. In summary, we implemented a simple LSO background subtraction method and demonstrated its effectiveness. The projection-based calculation formula yielded MDTA results that closely correlate with that obtained empirically and may have predicative value for imaging applications.

  12. Activation of the Notch signaling pathway promotes neurovascular repair after traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Qi-shan Ran

    2015-01-01

    Full Text Available The Notch signaling pathway plays a key role in angiogenesis and endothelial cell formation, but it remains unclear whether it is involved in vascular repair by endothelial progenitor cells after traumatic brain injury. Therefore, in the present study, we controlled the Notch signaling pathway using overexpression and knockdown constructs. Activation of the Notch signaling pathway by Notch1 or Jagged1 overexpression enhanced the migration, invasiveness and angiogenic ability of endothelial progenitor cells. Suppression of the Notch signaling pathway with Notch1 or Jagged1 siRNAs reduced the migratory capacity, invasiveness and angiogenic ability of endothelial progenitor cells. Activation of the Notch signaling pathway in vivo in a rat model of mild traumatic brain injury promoted neurovascular repair. These findings suggest that the activation of the Notch signaling pathway promotes blood vessel formation and tissue repair after brain trauma.

  13. The down-stream effects of mannan-induced lectin complement pathway activation depend quantitatively on alternative pathway amplification

    DEFF Research Database (Denmark)

    Harboe, Morten; Garred, Peter; Karlstrøm, Ellen

    2009-01-01

    was not observed even at high mannan concentrations since addition of the inhibiting anti-MBL mAb 3F8 completely abolished generation of the terminal C5b-9 complex (TCC). However, selective blockade of AP by anti-factor D inhibited more than 80% of TCC release into the fluid phase after LP activation showing...... that AP amplification is quantitatively responsible for the final effect of initial specific LP activation. TCC generation on the solid phase was distinctly but less inhibited by anti-fD. C2 bypass of the LP pathway could be demonstrated, and AP amplification was also essential during C2 bypass in LP...... as shown by complete inhibition of TCC generation in C2-deficient serum by anti-fD and anti-properdin antibodies. In conclusion, the down-stream effect of LP activation depends strongly on AP amplification in normal human serum and in the C2 bypass pathway....

  14. Accurate and reliable cancer classification based on probabilistic inference of pathway activity.

    Directory of Open Access Journals (Sweden)

    Junjie Su

    Full Text Available With the advent of high-throughput technologies for measuring genome-wide expression profiles, a large number of methods have been proposed for discovering diagnostic markers that can accurately discriminate between different classes of a disease. However, factors such as the small sample size of typical clinical data, the inherent noise in high-throughput measurements, and the heterogeneity across different samples, often make it difficult to find reliable gene markers. To overcome this problem, several studies have proposed the use of pathway-based markers, instead of individual gene markers, for building the classifier. Given a set of known pathways, these methods estimate the activity level of each pathway by summarizing the expression values of its member genes, and use the pathway activities for classification. It has been shown that pathway-based classifiers typically yield more reliable results compared to traditional gene-based classifiers. In this paper, we propose a new classification method based on probabilistic inference of pathway activities. For a given sample, we compute the log-likelihood ratio between different disease phenotypes based on the expression level of each gene. The activity of a given pathway is then inferred by combining the log-likelihood ratios of the constituent genes. We apply the proposed method to the classification of breast cancer metastasis, and show that it achieves higher accuracy and identifies more reproducible pathway markers compared to several existing pathway activity inference methods.

  15. Angiogenic activity of sesamin through the activation of multiple signal pathways

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Byung-Hee [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Lee, Jung Joon [Center for Molecular Cancer Research, Korea Research Institute of Bioscience and Biotechnology, Daejeon (Korea, Republic of); Kim, Jong-Dai [Division of Food Biotechnology, School of Biotechnology, Kangwon National University, Chuncheon (Korea, Republic of); Jeoung, Dooil; Lee, Hansoo [Division of Life Sciences, Kangwon National University, Chuncheon (Korea, Republic of); Choe, Jongseon; Ha, Kwon-Soo [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of); Kwon, Young-Geun [Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul (Korea, Republic of); Kim, Young-Myeong, E-mail: ymkim@kangwon.ac.kr [Vascular System Research Center and Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon (Korea, Republic of)

    2010-01-01

    The natural product sesamin has been known to act as a potent antioxidant and prevent endothelial dysfunction. We here found that sesamin increased in vitro angiogenic processes, such as endothelial cell proliferation, migration, and tube formation, as well as neovascularization in an animal model. This compound elicited the activation of multiple angiogenic signal modulators, such as ERK, Akt, endothelial nitric oxide synthase (eNOS), NO production, FAK, and p38 MAPK, but not Src. The MEK inhibitor PD98059 and the PI3K inhibitor Wortmannin specifically inhibited sesamin-induced activation of the ERK and Akt/eNOS pathways. These inhibitors reduced angiogenic events, with high specificity for MEK/ERK-dependent cell proliferation and migration and PI3K/Akt-mediated tube formation. Moreover, inhibition of p38 MAPK effectively inhibited sesamin-induced cell migration. The angiogenic activity of sesamin was not associated with VEGF expression. Furthermore, this compound did not induce vascular permeability and upregulated ICAM-1 and VCAM-1 expression, which are hallmarks of vascular inflammation. These results suggest that sesamin stimulates angiogenesis in vitro and in vivo through the activation of MEK/ERK-, PI3K/Akt/eNOS-, p125{sup FAK}-, and p38 MAPK-dependent pathways, without increasing vascular inflammation, and may be used for treating ischemic diseases and tissue regeneration.

  16. SOX9 drives WNT pathway activation in prostate cancer.

    Science.gov (United States)

    Ma, Fen; Ye, Huihui; He, Housheng Hansen; Gerrin, Sean J; Chen, Sen; Tanenbaum, Benjamin A; Cai, Changmeng; Sowalsky, Adam G; He, Lingfeng; Wang, Hongyun; Balk, Steven P; Yuan, Xin

    2016-05-02

    The transcription factor SOX9 is critical for prostate development, and dysregulation of SOX9 is implicated in prostate cancer (PCa). However, the SOX9-dependent genes and pathways involved in both normal and neoplastic prostate epithelium are largely unknown. Here, we performed SOX9 ChIP sequencing analysis and transcriptome profiling of PCa cells and determined that SOX9 positively regulates multiple WNT pathway genes, including those encoding WNT receptors (frizzled [FZD] and lipoprotein receptor-related protein [LRP] family members) and the downstream β-catenin effector TCF4. Analyses of PCa xenografts and clinical samples both revealed an association between the expression of SOX9 and WNT pathway components in PCa. Finally, treatment of SOX9-expressing PCa cells with a WNT synthesis inhibitor (LGK974) reduced WNT pathway signaling in vitro and tumor growth in murine xenograft models. Together, our data indicate that SOX9 expression drives PCa by reactivating the WNT/β-catenin signaling that mediates ductal morphogenesis in fetal prostate and define a subgroup of patients who would benefit from WNT-targeted therapy.

  17. Abnormal intrinsic brain activity in amnestic mild cognitive impairment revealed by amplitude of low-frequency fluctuation: a resting-state functional magnetic resonance imaging study

    Institute of Scientific and Technical Information of China (English)

    XI Qian; ZHAO Xiao-hu; WANG Pei-jun; GUO Qi-hao; HE Yong

    2013-01-01

    Background Previous studies have shown that brain functional activity in the resting state is impaired in Alzheimer's disease (AD) patients.However,alterations in intrinsic brain activity patterns in mild cognitive impairment (MCI) patients are poorly understood.This study aimed to explore the differences in regional intrinsic activities throughout the whole brain between aMCI patients and controls.Methods In the present study,resting-state functional magnetic resonance imaging (fMRI) was performed on 18 amnestic MCI (aMCI) patients,18 mild AD patients and 20 healthy elderly subjects.And amplitude of low-frequency fluctuation (ALFF) method was used.Results Compared with healthy elderly subjects,aMCI patients showed decreased ALFF in the right hippocampus and parahippocampal cortex,left lateral temporal cortex,and right ventral medial prefrontal cortex (vMPFC) and increased ALFF in the left temporal-parietal junction (TPJ) and inferior parietal Iobule (IPL).Mild AD patients showed decreased ALFF in the left TPJ,posterior IPL (plPL),and dorsolateral prefrontal cortex compared with aMCI patients.Mild AD patients also had decreased ALFF in the right posterior cingulate cortex,right vMPFC and bilateral dorsal MPFC (dMPFC) compared with healthy elderly subjects.Conclusions Decreased intrinsic activities in brain regions closely related to episodic memory were found in aMCI and AD patients.Increased TPJ and IPL activity may indicate compensatory mechanisms for loss of memory function in aMCI patients.These findings suggest that the fMRI based on ALFF analysis may provide a useful tool in the study of aMCI patients.

  18. Fresh tar (from biomass gasification) destruction with downstream catalysts: comparison of their intrinsic activity with a realistic kinetic model

    Energy Technology Data Exchange (ETDEWEB)

    Corella, J.; Narvaez, I.; Orio, A. [Complutense Univ. of Madrid (Spain). Dept. of Chemical Engineering

    1996-12-31

    A model for fresh tar destruction over catalysts placed downstream a biomass gasifier is presented. It includes the stoichio-metry and the calculation of the kinetic constants for the tar destruction. Catalysts studied include commercial Ni steam reforming catalysts and calcinated dolomites. Kinetic constants for tar destruction are calculated for several particle sizes, times- on-stream and temperatures of the catalyst and equivalence ratios in the gasifier. Such intrinsic kinetic constants allow a rigorous or scientific comparison of solids and conditions to be used in an advanced gasification process. (orig.) 4 refs.

  19. Second-site suppressors of HIV-1 capsid mutations: restoration of intracellular activities without correction of intrinsic capsid stability defects

    Directory of Open Access Journals (Sweden)

    Yang Ruifeng

    2012-04-01

    Full Text Available Abstract Background Disassembly of the viral capsid following penetration into the cytoplasm, or uncoating, is a poorly understood stage of retrovirus infection. Based on previous studies of HIV-1 CA mutants exhibiting altered capsid stability, we concluded that formation of a capsid of optimal intrinsic stability is crucial for HIV-1 infection. Results To further examine the connection between HIV-1 capsid stability and infectivity, we isolated second-site suppressors of HIV-1 mutants exhibiting unstable (P38A or hyperstable (E45A capsids. We identified the respective suppressor mutations, T216I and R132T, which restored virus replication in a human T cell line and markedly enhanced the fitness of the original mutants as revealed in single-cycle infection assays. Analysis of the corresponding purified N-terminal domain CA proteins by NMR spectroscopy demonstrated that the E45A and R132T mutations induced structural changes that are localized to the regions of the mutations, while the P38A mutation resulted in changes extending to neighboring regions in space. Unexpectedly, neither suppressor mutation corrected the intrinsic viral capsid stability defect associated with the respective original mutation. Nonetheless, the R132T mutation rescued the selective infectivity impairment exhibited by the E45A mutant in aphidicolin-arrested cells, and the double mutant regained sensitivity to the small molecule inhibitor PF74. The T216I mutation rescued the impaired ability of the P38A mutant virus to abrogate restriction by TRIMCyp and TRIM5α. Conclusions The second-site suppressor mutations in CA that we have identified rescue virus infection without correcting the intrinsic capsid stability defects associated with the P38A and E45A mutations. The suppressors also restored wild type virus function in several cell-based assays. We propose that while proper HIV-1 uncoating in target cells is dependent on the intrinsic stability of the viral capsid, the

  20. Alpha 1-antitrypsin Pittsburgh (Met358-->Arg) inhibits the contact pathway of intrinsic coagulation and alters the release of human neutrophil elastase during simulated extracorporeal circulation

    NARCIS (Netherlands)

    Wachtfogel, Y.T.; Bischoff, Rainer; Bauer, R; Hack, C.E.; Nuijens, J.H; Kucich, U.; Niewiarowski, S.; Edmunds, Jr. L.H.; Colman, R.W.

    1994-01-01

    Cardiopulmonary bypass prolongs bleeding time, increases postoperative blood loss, and triggers activation of plasma proteolytic enzyme systems and blood cells referred to as the "whole body inflammatory response". Contact of blood with synthetic surfaces leads to qualitative and quantitative

  1. Punica granatum (pomegranate) leaves extract induces apoptosis through mitochondrial intrinsic pathway and inhibits migration and invasion in non-small cell lung cancer in vitro.

    Science.gov (United States)

    Li, Yali; Yang, Fangfang; Zheng, Weidong; Hu, Mingxing; Wang, Juanxiu; Ma, Sisi; Deng, Yuanle; Luo, Yi; Ye, Tinghong; Yin, Wenya

    2016-05-01

    Most conventional treatments on non-small cell lung carcinoma always accompany with awful side effects, and the incidence and mortality rates of this cancer are increasing rapidly worldwide. The objective of this study was to examine the anticancer effects of extract of Punica granatum (pomegranate) leaves extract (PLE) on the non-small cell lung carcinoma cell line A549, H1299 and mouse Lewis lung carcinoma cell line LL/2 in vitro, and explore its mechanisms of action. Our results have shown that PLE inhibited cell proliferation in non-small cell lung carcinoma cell line in a concentration- and time-dependent manner. Flow cytometry (FCM) assay showed that PLE affected H1299 cell survival by arresting cell cycle progression in G2/M phase in a dose-dependent manner and inducing apoptosis. Moreover, PLE could also decrease the reactive oxygen species (ROS) and the mitochondrial membrane potential (ΔYm), indicating that PLE may induce apoptosis via mitochondria-mediated apoptotic pathway. Furthermore, PLE blocked H1299 cell migration and invasion, and the reduction of matrix metalloproteinase (MMP) MMP-2 and MMP-9 expression were also observed in vitro. These results suggested that PLE could be an effective and safe chemotherapeutic agent in non-small cell lung carcinoma treatment by inhibiting proliferation, inducing apoptosis, cell cycle arrest and impairing cell migration and invasion.

  2. Pathway modeling of microarray data: A case study of pathway activity changes in the testis following in utero exposure to dibutyl phthalate (DBP)

    Energy Technology Data Exchange (ETDEWEB)

    Ovacik, Meric A. [Chemical and Biochemical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States); Sen, Banalata [National Center for Environmental Assessment, U.S. Environmental Protection Agency, Research Triangle Park, NC 27709 (United States); Euling, Susan Y. [National Center for Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460 (United States); Gaido, Kevin W. [U.S. Food and Drug Administration, Center for Veterinary Medicine, Office of New Animal Drug Evaluation, Division of Human Food Safety, Rockville, MD 20855 (United States); Ierapetritou, Marianthi G. [Chemical and Biochemical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States); Androulakis, Ioannis P., E-mail: yannis@rci.rutgers.edu [Chemical and Biochemical Engineering Department, Rutgers University, Piscataway, NJ 08854 (United States); Biomedical Engineering Department, Rutgers University, NJ 08854 (United States)

    2013-09-15

    Pathway activity level analysis, the approach pursued in this study, focuses on all genes that are known to be members of metabolic and signaling pathways as defined by the KEGG database. The pathway activity level analysis entails singular value decomposition (SVD) of the expression data of the genes constituting a given pathway. We explore an extension of the pathway activity methodology for application to time-course microarray data. We show that pathway analysis enhances our ability to detect biologically relevant changes in pathway activity using synthetic data. As a case study, we apply the pathway activity level formulation coupled with significance analysis to microarray data from two different rat testes exposed in utero to Dibutyl Phthalate (DBP). In utero DBP exposure in the rat results in developmental toxicity of a number of male reproductive organs, including the testes. One well-characterized mode of action for DBP and the male reproductive developmental effects is the repression of expression of genes involved in cholesterol transport, steroid biosynthesis and testosterone synthesis that lead to a decreased fetal testicular testosterone. Previous analyses of DBP testes microarray data focused on either individual gene expression changes or changes in the expression of specific genes that are hypothesized, or known, to be important in testicular development and testosterone synthesis. However, a pathway analysis may inform whether there are additional affected pathways that could inform additional modes of action linked to DBP developmental toxicity. We show that Pathway activity analysis may be considered for a more comprehensive analysis of microarray data.

  3. Regulator of G Protein Signaling 6 (RGS6) Induces Apoptosis via a Mitochondrial-dependent Pathway Not Involving Its GTPase-activating Protein Activity*

    Science.gov (United States)

    Maity, Biswanath; Yang, Jianqi; Huang, Jie; Askeland, Ryan W.; Bera, Soumen; Fisher, Rory A.

    2011-01-01

    Regulator of G protein signaling 6 (RGS6) is a member of a family of proteins called RGS proteins, which function as GTPase-activating proteins (GAPs) for Gα subunits. Given the role of RGS6 as a G protein GAP, the link between G protein activation and cancer, and a reduction of cancer risk in humans expressing a RGS6 SNP leading to its increased translation, we hypothesized that RGS6 might function to inhibit growth of cancer cells. Here, we show a marked down-regulation of RGS6 in human mammary ductal epithelial cells that correlates with the progression of their transformation. RGS6 exhibited impressive antiproliferative actions in breast cancer cells, including inhibition of cell growth and colony formation and induction of cell cycle arrest and apoptosis by mechanisms independent of p53. RGS6 activated the intrinsic pathway of apoptosis involving regulation of Bax/Bcl-2, mitochondrial outer membrane permeabilization (MOMP), cytochrome c release, activation of caspases-3 and -9, and poly(ADP-ribose) polymerase cleavage. RGS6 promoted loss of mitochondrial membrane potential (ΔΨm) and increases in reactive oxygen species (ROS). RGS6-induced caspase activation and loss of ΔΨm was mediated by ROS, suggesting an amplification loop in which ROS provided a feed forward signal to induce MOMP, caspase activation, and cell death. Loss of RGS6 in mouse embryonic fibroblasts dramatically impaired doxorubicin-induced growth suppression and apoptosis. Surprisingly, RGS6-induced apoptosis in both breast cancer cells and mouse embryonic fibroblasts does not require its GAP activity toward G proteins. This work demonstrates a novel signaling action of RGS6 in cell death pathways and identifies it as a possible therapeutic target for treatment of breast cancer. PMID:21041304

  4. Regulator of G protein signaling 6 (RGS6) induces apoptosis via a mitochondrial-dependent pathway not involving its GTPase-activating protein activity.

    Science.gov (United States)

    Maity, Biswanath; Yang, Jianqi; Huang, Jie; Askeland, Ryan W; Bera, Soumen; Fisher, Rory A

    2011-01-14

    Regulator of G protein signaling 6 (RGS6) is a member of a family of proteins called RGS proteins, which function as GTPase-activating proteins (GAPs) for Gα subunits. Given the role of RGS6 as a G protein GAP, the link between G protein activation and cancer, and a reduction of cancer risk in humans expressing a RGS6 SNP leading to its increased translation, we hypothesized that RGS6 might function to inhibit growth of cancer cells. Here, we show a marked down-regulation of RGS6 in human mammary ductal epithelial cells that correlates with the progression of their transformation. RGS6 exhibited impressive antiproliferative actions in breast cancer cells, including inhibition of cell growth and colony formation and induction of cell cycle arrest and apoptosis by mechanisms independent of p53. RGS6 activated the intrinsic pathway of apoptosis involving regulation of Bax/Bcl-2, mitochondrial outer membrane permeabilization (MOMP), cytochrome c release, activation of caspases-3 and -9, and poly(ADP-ribose) polymerase cleavage. RGS6 promoted loss of mitochondrial membrane potential (ΔΨ(m)) and increases in reactive oxygen species (ROS). RGS6-induced caspase activation and loss of ΔΨ(m) was mediated by ROS, suggesting an amplification loop in which ROS provided a feed forward signal to induce MOMP, caspase activation, and cell death. Loss of RGS6 in mouse embryonic fibroblasts dramatically impaired doxorubicin-induced growth suppression and apoptosis. Surprisingly, RGS6-induced apoptosis in both breast cancer cells and mouse embryonic fibroblasts does not require its GAP activity toward G proteins. This work demonstrates a novel signaling action of RGS6 in cell death pathways and identifies it as a possible therapeutic target for treatment of breast cancer.

  5. Hedgehog pathway activation in human transitional cell carcinoma of the bladder

    OpenAIRE

    2012-01-01

    Background: The Hedgehog (Hh) signalling pathway functions as an organiser in embryonic development. Recent studies have shown constitutive activation of this pathway in various malignancies, but its role in bladder cancer remains poorly studied. Methods: Expression levels of 31 genes and 9 microRNAs (miRNAs) involved in the Hh pathway were determined by quantitative real-time RT–PCR in 71 bladder tumour samples (21 muscle-invasive (MIBC) and 50 non-muscle-invasive (NMIBC) bladder cancers), a...

  6. Activation of the Notch signaling pathway promotes neurovascular repair after traumatic brain injury

    OpenAIRE

    2015-01-01

    The Notch signaling pathway plays a key role in angiogenesis and endothelial cell formation, but it remains unclear whether it is involved in vascular repair by endothelial progenitor cells after traumatic brain injury. Therefore, in the present study, we controlled the Notch signaling pathway using overexpression and knockdown constructs. Activation of the Notch signaling pathway by Notch1 or Jagged1 overexpression enhanced the migration, invasiveness and angiogenic ability of endothelial pr...

  7. Cisplatin Induces Cytotoxicity through the Mitogen-Activated Protein Kinase Pathways ana Activating Transcription Factor 3

    Directory of Open Access Journals (Sweden)

    Carly St. Germain

    2010-07-01

    Full Text Available The mechanisms underlying the proapoptotic effect of the chemotherapeutic agent, cisplatin, are largely undefined. Understanding the mechanisms regulating cisplatin cytotoxicity may uncover strategies to enhance the efficacy of this important therapeutic agent. This study evaluates the role of activating transcription factor 3 (ATF3 as a mediator of cisplatin-induced cytotoxicity. Cytotoxic doses of cisplatin and carboplatin treatments consistently induced ATF3 expression in five tumor-derived cell lines. Characterization of this induction revealed a p53, BRCA1, and integrated stress response-independent mechanism, all previously implicated in stress-mediated ATF3 induction. Analysis of mitogenactivated protein kinase (MAPK pathway involvement in ATF3 induction by cisplatin revealed a MAPK-dependent mechanism. Cisplatin treatment combined with specific inhibitors to each MAPK pathway (c-Jun N-terminal kinase, extracellularsignal-regulated kinase, and p38 resulted in decreasedATF3 induction at the protein level. MAPK pathway inhibition led to decreased ATF3 messenger RNA expression and reduced cytotoxic effects of cisplatin as measured by the 3-(4,5-dimethylthiazol-2-ylF2,5-diphenyltetrazolium bromide cell viability assay. In A549 lung carcinoma cells, targeting ATF3 with specific small hairpin RNA also attenuated the cytotoxic effects of cisplatin. Similarly, ATF3-/murine embryonic fibroblasts (MEFs were shown to be less sensitive to cisplatin-induced cytotoxicity compared with ATF3+/+ MEFs. This study identifies cisplatin as a MAPK pathway-dependent inducer of ATF3, whose expression influences cisplatin’s cytotoxic effects.

  8. Axon Regeneration Requires A Conserved MAP Kinase Pathway

    OpenAIRE

    Hammarlund, Marc; Nix, Paola; Hauth, Linda; Jorgensen, Erik M.; Bastiani, Michael

    2009-01-01

    Regeneration of injured neurons can restore function, but most neurons regenerate poorly or not at all. The failure to regenerate in some cases is due to a lack of activation of cell-intrinsic regeneration pathways. Thus, these pathways might be targeted for the development of therapies that can restore neuron function after injury or disease. Here, we show that the DLK-1 MAP kinase pathway is essential for regeneration in C. elegans motor neurons. Loss of this pathway eliminates regeneration...

  9. Immune signaling pathways activated in response to different pathogenic micro-organisms in Bombyx mori.

    Science.gov (United States)

    Liu, Wei; Liu, Jiabin; Lu, Yahong; Gong, Yongchang; Zhu, Min; Chen, Fei; Liang, Zi; Zhu, Liyuan; Kuang, Sulan; Hu, Xiaolong; Cao, Guangli; Xue, Renyu; Gong, Chengliang

    2015-06-01

    The JAK/STAT, Toll, Imd, and RNAi pathways are the major signaling pathways associated with insect innate immunity. To explore the different immune signaling pathways triggered in response to pathogenic micro-organism infections in the silkworm, Bombyx mori, the expression levels of the signal transducer and activator of transcription (BmSTAT), spatzle-1 (Bmspz-1), peptidoglycan-recognition protein LB (BmPGRP-LB), peptidoglycan-recognition protein LE (BmPGRP-LE), argonaute 2 (Bmago2), and dicer-2 (Bmdcr2) genes after challenge with Escherichia coli (E. coli), Serratiamarcescens (Sm), Bacillus bombyseptieus (Bab), Beauveriabassiana (Beb), nucleopolyhedrovirus (BmNPV), cypovirus (BmCPV), bidensovirus (BmBDV), or Nosemabombycis (Nb) were determined using real-time PCR. We found that the JAK/STAT pathway could be activated by challenge with BmNPV and BmBDV, the Toll pathway could be most robustly induced by challenge with Beb, the Imd pathway was mainly activated in response to infection by E. coli and Sm, and the RNAi pathway was not activated by viral infection, but could be triggered by some bacterial infections. These findings yield insights into the immune signaling pathways activated in response to different pathogenic micro-organisms in the silkworm.

  10. Hedgehog pathway activity in the LADY prostate tumor model

    OpenAIRE

    Kasper Susan; Crylen Curtis; Gu Guangyu; Gipp Jerry; Bushman Wade

    2007-01-01

    Abstract Background Robust Hedgehog (Hh) signaling has been implicated as a common feature of human prostate cancer and an important stimulus of tumor growth. The role of Hh signaling has been studied in several xenograft tumor models, however, the role of Hh in tumor development in a transgenic prostate cancer model has never been examined. Results We analyzed expression of Hh pathway components and conserved Hh target genes along with progenitor cell markers and selected markers of epitheli...

  11. Unraveling the adipocyte inflammomodulatory pathways activated by North American ginseng.

    Science.gov (United States)

    Wilson, S A F; Wong, M H T; Stryjecki, C; De Boer, A; Lui, E M K; Mutch, D M

    2013-03-01

    North American (NA) ginseng (Panax quinquefolius) is a popular natural health product (NHP) that has been demonstrated to regulate immune function, inflammatory processes and response to stress and fatigue. Recent evidence suggests that various extracts of NA ginseng may have different bioactivities because of distinct profiles of ginsenosides and polysaccharides. To date, the bioactive role of ginseng on adipocytes remains relatively unexplored. The goal of this work was to study the extract-specific bioactivity of NA ginseng on differentiated preadipocyte gene expression and adipocytokine secretion. In vitro differentiated 3T3-L1 preadipocytes were treated with 25 and 50 μg ml of either crude ethanol (EtOH) or aqueous (AQ) NA ginseng extracts, or polysaccharide and ginsenoside extracts isolated from the AQ extract. Global gene expression was studied with microarrays and the resulting data were analyzed with functional pathway analysis. Adipocytokine secretion was also measured in media. Pathway analysis indicated that the AQ extract, and in particular the polysaccharide extract, triggered a global inflammomodulatory response in differentiated preadipocytes. Specifically, the expression of Il-6 (interleukin 6), Ccl5 (chemokine (C-C motif) ligand 5), Nfκb (nuclear factor-kappaB) and Tnfα (tumor necrosis factor alpha) was increased. These effects were also reflected at the protein level through the increased secretion of IL-6 and CCL5. No effect was seen with the EtOH extract or ginsenoside extract. Using a specific toll-like receptor 4 (TLR4) inhibitor reduced the upregulation of inflammatory gene expression, indicating the relevance of this pathway for the signaling capacity of NA ginseng polysaccharides. This work emphasizes the distinct bioactivities of different ginseng extracts on differentiated preadipocyte signaling pathways, and highlights the importance of TLR4 for mediating the inflammomodulatory role of ginseng polysaccharides.

  12. Acupuncture activates signal transduction pathways related to brain-tissue restoration after ischemic injury.

    Science.gov (United States)

    Tian, Haomei; Zhang, Hong; Zhu, Junbao; Zhang, Juan; Cai, Hening; Zhang, Yuchen; Chen, Chutao

    2012-08-25

    A middle cerebral artery occlusion-model was established in rats using the improved thread embolism method. Rats were treated with acupuncture at either Dazhui (DU14), Renzhong (DU26), Baihui (DU20), or a non-meridian point. Detection with protein-chip technology showed that the level of protein phosphorylation in both groups was upregulated or downregulated depending on the signaling pathway compared with the model group that did not receive acupuncture. Analysis of proteins showing downregulated phosphorylation revealed that five signaling pathways were activated in the acupuncture-treatment group, while only two were activated in the acupuncture- control group. In contrast, analysis of proteins showing upregulated phosphorylation revealed only one pathway was activated in the acupuncture-treatment group, whereas four pathways were activated in the acupuncture-control group. Furthermore, the number of activated proteins in the acupuncture-treatment group was not only higher than the acupuncture-control group, but unlike the acupuncture-control group, the majority of activated proteins were key proteins in the signaling pathways. Our findings indicate that acupuncture at specific points can activate multiple signaling pathways to promote the restoration of brain tissue following ischemic injury, and that this is based on a combination of effects resulting from multiple pathways, targets, and means.

  13. The cytotoxicity of methacryloxylethyl cetyl ammonium chloride, a cationic antibacterial monomer, is related to oxidative stress and the intrinsic mitochondrial apoptotic pathway.

    Science.gov (United States)

    Ma, Sai; Shan, Le-qun; Xiao, Yu-hong; Li, Fang; Huang, Li; Shen, Lijuan; Chen, Ji-hua

    2011-11-01

    Antibacterial monomers incorporated in dentin bonding systems may have toxic effects on the pulp. Thus, the cytotoxicity of antibacterial monomers and its underlying mechanisms must be elucidated to improve the safety of antibacterial monomer application. The influence of an antibacterial monomer, methacryloxylethyl cetyl ammonium chloride (DMAE-CB), on the vitality of L929 mouse fibroblasts was tested using MTT assay. Cell cycle progression was studied using flow cytometry. Production of intracellular reactive oxygen species (ROS) after DMAE-CB treatment was measured using 2,7-dichlorodihydrofluorescein diacetate staining and flow cytometry analysis. Loss of mitochondrial membrane potential, disturbance of Bcl-2 and Bax expression, as well as release of cytochrome C were also measured using flow cytometry analysis or Western blot to explore the possible involvement of the mitochondrial-related apoptotic pathway. DMAE-CB elicited cell death in a dose-dependent manner and more than 50% of cells were killed after treatment with 30 µM of the monomer. Both necrosis and apoptosis were observed. DMAE-CB also induced G1- and G2-phase arrest. Increased levels of intracellular ROS were observed after 1 h and this overproduction was further enhanced by 6-h treatment with the monomer. DMAE-CB may cause apoptosis by disturbing the expression of Bcl-2 and Bax, reducing the mitochondrial potential and inducing release of cytochrome C. Taken together, these findings suggest that the toxicity of the antibacterial monomer DMAE-CB is associated with ROS production, mitochondrial dysfunction, cell cycle disturbance, and cell apoptosis/necrosis.

  14. Activation of the Notch signaling pathway promotes neurovascular repair after traumatic brain injury

    Institute of Scientific and Technical Information of China (English)

    Qi-shan Ran; Yun-hu Yu; Xiao-hong Fu; Yuan-chao Wen

    2015-01-01

    The Notch signaling pathway plays a key role in angiogenesis and endothelial cell formation, but it remains unclear whether it is involved in vascular repair by endothelial progenitor cells after traumatic brain injury. Therefore, in the present study, we controlled the Notch signaling path-way using overexpression and knockdown constructs. Activation of the Notch signaling pathway by Notch1 or Jagged1 overexpression enhanced the migration, invasiveness and angiogenic ability of endothelial progenitor cells. Suppression of the Notch signaling pathway with Notch1 or Jagged1 siRNAs reduced the migratory capacity, invasiveness and angiogenic ability of endo-thelial progenitor cells. Activation of the Notch signaling pathwayin vivo in a rat model of mild traumatic brain injury promoted neurovascular repair. These ifndings suggest that the activation of the Notch signaling pathway promotes blood vessel formation and tissue repair after brain trauma.

  15. Naphthazarin protects against glutamate-induced neuronal death via activation of the Nrf2/ARE pathway

    Energy Technology Data Exchange (ETDEWEB)

    Son, Tae Gen; Kawamoto, Elisa M.; Yu, Qian-Sheng; Greig, Nigel H. [Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, 251 Bayview Blvd., Baltimore, MD 21224 (United States); Mattson, Mark P. [Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, 251 Bayview Blvd., Baltimore, MD 21224 (United States); Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD (United States); Camandola, Simonetta, E-mail: camandolasi@mail.nih.gov [Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, 251 Bayview Blvd., Baltimore, MD 21224 (United States)

    2013-04-19

    Highlights: •Naphthazarin activates the Nrf2/ARE pathway. •Naphthazarin induces Nrf2-driven genes in neurons and astrocytes. •Naphthazarin protects neurons against excitotoxicity. -- Abstract: Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. We previously screened several natural phytochemicals and identified plumbagin as a novel activator of the Nrf2/ARE pathway that can protect neurons against ischemic injury. Here we extended our studies to natural and synthetic derivatives of plumbagin. We found that 5,8-dimethoxy-1,4-naphthoquinone (naphthazarin) is a potent activator of the Nrf2/ARE pathway, up-regulates the expression of Nrf2-driven genes in primary neuronal and glial cultures, and protects neurons against glutamate-induced excitotoxicity.

  16. Quercetin regulates insulin like growth factor signaling and induces intrinsic and extrinsic pathway mediated apoptosis in androgen independent prostate cancer cells (PC-3).

    Science.gov (United States)

    Senthilkumar, Kalimuthu; Elumalai, Perumal; Arunkumar, Ramachandran; Banudevi, Sivanantham; Gunadharini, Nandagopal Dharmalingam; Sharmila, Govindaraj; Selvakumar, Kandaswamy; Arunakaran, Jagadeesan

    2010-11-01

    Progression of prostate cancer is facilitated by growth factors that activate critical signaling cascades thereby promote prostate cancer cell growth, survival, and migration. To investigate the effect of quercetin on insulin-like growth factor signaling and apoptosis in androgen independent prostate cancer cells (PC-3), IGF-IR, PI-3K, p-Akt, Akt, cyclin D1, Bad, cytochrome c, PARP, caspases-9 and 10 protein levels were assessed by western blot analysis. Mitochondrial membrane potency was detected by rhodamine-123 staining. Quercetin induced caspase-3 activity assay was performed for activation of apoptosis. Further, RT-PCR was also performed for Bad, IGF-I, II, IR, and IGFBP-3 mRNA expression. Quercetin significantly increases the proapoptotic mRNA levels of Bad, IGFBP-3 and protein levels of Bad, cytochrome C, cleaved caspase-9, caspase-10, cleaved PARP and caspase-3 activity in PC-3 cells. IGF-IRβ, PI3K, p-Akt, and cyclin D1 protein expression and mRNA levels of IGF-I, II and IGF-IR were decreased significantly. Further, treatment with PI3K inhibitor (LY294002) and quercetin showed decreased p-Akt levels. Apoptosis is confirmed by loss of mitochondrial membrane potential in quercetin treated PC-3 cells. This study suggests that quercetin decreases the survival of androgen independent prostate cancer cells by modulating the expression of insulin-like growth factors (IGF) system components, signaling molecules and induces apoptosis, which could be very useful for the androgen independent prostate cancer treatment.

  17. USP21 regulates Hippo pathway activity by mediating MARK protein turnover

    DEFF Research Database (Denmark)

    Nguyen, Thanh Hung; Kugler, Jan-Michael; Loya, Anand Chainsukh

    2017-01-01

    The Hippo pathway, which acts to repress the activity of YAP and TAZ trancriptional co-activators, serve as a barrier for oncogenic transformation. Unlike other oncoproteins, YAP and TAZ are rarely activated by mutations or amplified in cancer. However, elevated YAP/TAZ activity is frequently obs...

  18. Impact of the Smoothened inhibitor, IPI-926, on smoothened ciliary localization and Hedgehog pathway activity.

    Directory of Open Access Journals (Sweden)

    Marisa O Peluso

    Full Text Available A requisite step for canonical Hedgehog (Hh pathway activation by Sonic Hedgehog (Shh ligand is accumulation of Smoothened (Smo to the primary cilium (PC. Activation of the Hh pathway has been implicated in a broad range of cancers, and several Smo antagonists are being assessed clinically, one of which is approved for the treatment of advanced basal cell carcinoma. Recent reports demonstrate that various Smo antagonists differentially impact Smo localization to the PC while still exerting inhibitory activity. In contrast to other synthetic small molecule Smo antagonists, the natural product cyclopamine binds to and promotes ciliary accumulation of Smo and "primes" cells for Hh pathway hyper-responsiveness after compound withdrawal. We compared the properties of IPI-926, a semi-synthetic cyclopamine analog, to cyclopamine with regard to potency, ciliary Smo accumulation, and Hh pathway activity after compound withdrawal. Like cyclopamine, IPI-926 promoted accumulation of Smo to the PC. However, in contrast to cyclopamine, IPI-926 treatment did not prime cells for hyper-responsiveness to Shh stimulation after compound withdrawal, but instead demonstrated continuous inhibition of signaling. By comparing the levels of drug-induced ciliary Smo accumulation with the degree of Hh pathway activity after compound withdrawal, we propose that a critical threshold of ciliary Smo is necessary for "priming" activity to occur. This "priming" appears achievable with cyclopamine, but not IPI-926, and is cell-line dependent. Additionally, IPI-926 activity was evaluated in a murine tumor xenograft model and a pharmacokinetic/pharmacodynamic relationship was examined to assess for in vivo evidence of Hh pathway hyper-responsiveness. Plasma concentrations of IPI-926 correlated with the degree and duration of Hh pathway suppression, and pathway activity did not exceed baseline levels out to 96 hours post dose. The overall findings suggest that IPI-926 possesses

  19. Treponema denticola activates mitogen-activated protein kinase signal pathways through Toll-like receptor 2.

    Science.gov (United States)

    Ruby, John; Rehani, Kunal; Martin, Michael

    2007-12-01

    Treponema denticola, a spirochete indigenous to the oral cavity, is associated with host inflammatory responses to anaerobic polymicrobial infections of the root canal, periodontium, and alveolar bone. However, the cellular mechanisms responsible for the recognition of T. denticola by the innate immune system and the underlying cell signaling pathways that regulate the inflammatory response to T. denticola are currently unresolved. In this study, we demonstrate that T. denticola induces innate immune responses via the utilization of Toll-like receptor 2 (TLR2) but not TLR4. Assessment of TLR2/1 and TLR2/6 heterodimers revealed that T. denticola predominantly utilizes TLR2/6 for the induction of cellular responses. Analysis of the mitogen-activated protein kinase (MAPK) signaling pathway in T. denticola-stimulated monocytes identified a prolonged up-regulation of the MAPK extracellular signal-related kinase 1/2 (ERK1/2) and p38, while no discernible increase in phospho-c-Jun N-terminal kinase 1/2 (JNK1/2) levels was observed. With the aid of pharmacological inhibitors selectively targeting ERK1/2 via the mitogen-activated protein kinase/extracellular signal-related kinase 1/2 kinase and p38, we further demonstrate that ERK1/2 and p38 play a major role in T. denticola-mediated pro- and anti-inflammatory cytokine production.

  20. Functional protein pathway activation mapping of the progression of normal skin to squamous cell carcinoma.

    Science.gov (United States)

    Einspahr, Janine G; Calvert, Valerie; Alberts, David S; Curiel-Lewandrowski, Clara; Warneke, James; Krouse, Robert; Stratton, Steven P; Liotta, Lance; Longo, Caterina; Pellacani, Giovanni; Pellicani, Giovanni; Prasad, Anil; Sagerman, Paul; Bermudez, Yira; Deng, Jianghong; Bowden, G Timothy; Petricoin, Emanuel F

    2012-03-01

    Reverse phase protein microarray analysis was used to identify cell signaling derangements in squamous cell carcinoma (SCC) compared with actinic keratosis (AK) and upper inner arm (UIA). We analyzed two independent tissue sets with isolation and enrichment of epithelial cells by laser capture microdissection. Set 1 served as a pilot and a means to identify protein pathway activation alterations that could be further validated in a second independent set. Set 1 was comprised of 4 AK, 13 SCC, and 20 UIA. Set 2 included 15 AK, 9 SCCs, and 20 UIAs. Activation of 51 signaling proteins, known to be involved in tumorigenesis, were assessed for set 1 and showed that the MEK-ERK [mitogen-activated protein (MAP)/extracellular signal-regulated (ERK; MEK)] pathway was activated in SCC compared with AK and UIA, and that epidermal growth factor receptor (EGFR) and mTOR pathways were aberrantly activated in SCC. Unsupervised two-way hierarchical clustering revealed that AK and UIA shared a common signaling network activation architecture while SCC was dramatically different. Statistical analysis found that prosurvival signaling through phosphorylation of ASK and 4EBP1 as well as increased Bax and Bak expression was higher in AK compared with UIA. We expanded pathway network activation mapping in set 2 to 101 key signaling proteins, which corroborated activation of MEK-ERK, EGFR, and mTOR pathways through discovery of a number of upstream and downstream signaling molecules within these pathways to conclude that SCC is indeed a pathway activation-driven disease. Pathway activation mapping of SCC compared with AK revealed several interconnected networks that could be targeted with drug therapy for potential chemoprevention and therapeutic applications.

  1. MAPK pathway activation by chronic lead-exposure increases vascular reactivity through oxidative stress/cyclooxygenase-2-dependent pathways

    Energy Technology Data Exchange (ETDEWEB)

    Simões, Maylla Ronacher, E-mail: yllars@hotmail.com [Dept. of Physiological Sciences, Federal University of Espirito Santo, Vitória, ES CEP 29040-091 (Brazil); Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid (Spain); Aguado, Andrea [Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid (Spain); Fiorim, Jonaína; Silveira, Edna Aparecida; Azevedo, Bruna Fernandes; Toscano, Cindy Medice [Dept. of Physiological Sciences, Federal University of Espirito Santo, Vitória, ES CEP 29040-091 (Brazil); Zhenyukh, Olha; Briones, Ana María [Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid (Spain); Alonso, María Jesús [Dept. of Biochemistry, Physiology and Molecular Genetics, Universidad Rey Juan Carlos, Alcorcón (Spain); Vassallo, Dalton Valentim [Dept. of Physiological Sciences, Federal University of Espirito Santo, Vitória, ES CEP 29040-091 (Brazil); Health Science Center of Vitória-EMESCAM, Vitória, ES CEP 29045-402 (Brazil); Salaices, Mercedes, E-mail: mercedes.salaices@uam.es [Department of Pharmacology, Universidad Autonoma de Madrid, Instituto de Investigación Hospital Universitario La Paz (IdiPAZ), Madrid (Spain)

    2015-03-01

    Chronic exposure to low lead concentration produces hypertension; however, the underlying mechanisms remain unclear. We analyzed the role of oxidative stress, cyclooxygenase-2-dependent pathways and MAPK in the vascular alterations induced by chronic lead exposure. Aortas from lead-treated Wistar rats (1st dose: 10 μg/100 g; subsequent doses: 0.125 μg/100 g, intramuscular, 30 days) and cultured aortic vascular smooth muscle cells (VSMCs) from Sprague Dawley rats stimulated with lead (20 μg/dL) were used. Lead blood levels of treated rats attained 21.7 ± 2.38 μg/dL. Lead exposure increased systolic blood pressure and aortic ring contractile response to phenylephrine, reduced acetylcholine-induced relaxation and did not affect sodium nitroprusside relaxation. Endothelium removal and L-NAME left-shifted the response to phenylephrine more in untreated than in lead-treated rats. Apocynin and indomethacin decreased more the response to phenylephrine in treated than in untreated rats. Aortic protein expression of gp91(phox), Cu/Zn-SOD, Mn-SOD and COX-2 increased after lead exposure. In cultured VSMCs lead 1) increased superoxide anion production, NADPH oxidase activity and gene and/or protein levels of NOX-1, NOX-4, Mn-SOD, EC-SOD and COX-2 and 2) activated ERK1/2 and p38 MAPK. Both antioxidants and COX-2 inhibitors normalized superoxide anion production, NADPH oxidase activity and mRNA levels of NOX-1, NOX-4 and COX-2. Blockade of the ERK1/2 and p38 signaling pathways abolished lead-induced NOX-1, NOX-4 and COX-2 expression. Results show that lead activation of the MAPK signaling pathways activates inflammatory proteins such as NADPH oxidase and COX-2, suggesting a reciprocal interplay and contribution to vascular dysfunction as an underlying mechanisms for lead-induced hypertension. - Highlights: • Lead-exposure increases oxidative stress, COX-2 expression and vascular reactivity. • Lead exposure activates MAPK signaling pathway. • ROS and COX-2 activation by

  2. Xylazine Activates Adenosine Monophosphate-Activated Protein Kinase Pathway in the Central Nervous System of Rats

    Science.gov (United States)

    Shi, Xing-Xing; Yin, Bai-Shuang; Yang, Peng; Chen, Hao; Li, Xin; Su, Li-Xue; Fan, Hong-Gang; Wang, Hong-Bin

    2016-01-01

    Xylazine is a potent analgesic extensively used in veterinary and animal experimentation. Evidence exists that the analgesic effect can be inhibited using adenosine 5’-monophosphate activated protein kinase (AMPK) inhibitors. Considering this idea, the aim of this study was to investigate whether the AMPK signaling pathway is involved in the central analgesic mechanism of xylazine in the rat. Xylazine was administrated via the intraperitoneal route. Sprague-Dawley rats were sacrificed and the cerebral cortex, cerebellum, hippocampus, thalamus and brainstem were collected for determination of liver kinase B1 (LKB1) and AMPKα mRNA expression using quantitative real-time polymerase chain reaction (qPCR), and phosphorylated LKB1 and AMPKα levels using western blot. The results of our study showed that compared with the control group, xylazine induced significant increases in AMPK activity in the cerebral cortex, hippocampus, thalamus and cerebellum after rats received xylazine (P < 0.01). Increased AMPK activities were accompanied with increased phosphorylation levels of LKB1 in corresponding regions of rats. The protein levels of phosphorylated LKB1 and AMPKα in these regions returned or tended to return to control group levels. However, in the brainstem, phosphorylated LKB1 and AMPKα protein levels were decreased by xylazine compared with the control (P < 0.05). In conclusion, our data indicates that xylazine alters the activities of LKB1 and AMPK in the central nervous system of rats, which suggests that xylazine affects the regulatory signaling pathway of the analgesic mechanism in the rat brain. PMID:27049320

  3. Blockage of both the extrinsic and intrinsic pathways of diazinon-induced apoptosis in PaTu cells by magnesium oxide and selenium nanoparticles.

    Science.gov (United States)

    Shiri, Mahdi; Navaei-Nigjeh, Mona; Baeeri, Maryam; Rahimifard, Mahban; Mahboudi, Hossein; Shahverdi, Ahmad Reza; Kebriaeezadeh, Abbas; Abdollahi, Mohammad

    Diazinon (DZ) is an organophosphorus insecticide that acts as an acetylcholinesterase inhibitor. It is important to note that it can induce oxidative stress, lipid peroxidation, diabetic disorders, and cytotoxicity. Magnesium oxide (MgO) and selenium nanoparticles (Se NPs) showed promising protection against oxidative stress, lipid peroxidation, cytotoxicity, and diabetic disorders. Therefore, this study was conducted to explore the possible protective mechanisms of MgO and Se NPs against DZ-induced cytotoxicity in PaTu cell line. Cytotoxicity of DZ, in the presence or absence of effective doses of MgO and Se NPs, was determined in human pancreatic cancer cell line (PaTu cells) after 24 hours of exposure by using mitochondrial activity and mitochondrial membrane potential assays. Then, the insulin, proinsulin, and C-peptide release; caspase-3 and -9 activities; and total thiol molecule levels were assessed. Determination of cell viability, including apoptotic and necrotic cells, was assessed via acridine orange/ethidium bromide double staining. Furthermore, expression of 15 genes associated with cell death/apoptosis in various phenomena was examined after 24 hours of contact with DZ and NPs by using real-time polymerase chain reaction. Compared to the individual cases, the group receiving the combination of MgO and Se NPs showed more beneficial effects in reducing the toxicity of DZ. Cotreatment of PaTu cell lines with MgO and Se NPs counteracts the toxicity of DZ on insulin-producing cells.

  4. Blockage of both the extrinsic and intrinsic pathways of diazinon-induced apoptosis in PaTu cells by magnesium oxide and selenium nanoparticles

    Science.gov (United States)

    Shiri, Mahdi; Navaei-Nigjeh, Mona; Baeeri, Maryam; Rahimifard, Mahban; Mahboudi, Hossein; Shahverdi, Ahmad Reza; Kebriaeezadeh, Abbas; Abdollahi, Mohammad

    2016-01-01

    Diazinon (DZ) is an organophosphorus insecticide that acts as an acetylcholinesterase inhibitor. It is important to note that it can induce oxidative stress, lipid peroxidation, diabetic disorders, and cytotoxicity. Magnesium oxide (MgO) and selenium nanoparticles (Se NPs) showed promising protection against oxidative stress, lipid peroxidation, cytotoxicity, and diabetic disorders. Therefore, this study was conducted to explore the possible protective mechanisms of MgO and Se NPs against DZ-induced cytotoxicity in PaTu cell line. Cytotoxicity of DZ, in the presence or absence of effective doses of MgO and Se NPs, was determined in human pancreatic cancer cell line (PaTu cells) after 24 hours of exposure by using mitochondrial activity and mitochondrial membrane potential assays. Then, the insulin, proinsulin, and C-peptide release; caspase-3 and -9 activities; and total thiol molecule levels were assessed. Determination of cell viability, including apoptotic and necrotic cells, was assessed via acridine orange/ethidium bromide double staining. Furthermore, expression of 15 genes associated with cell death/apoptosis in various phenomena was examined after 24 hours of contact with DZ and NPs by using real-time polymerase chain reaction. Compared to the individual cases, the group receiving the combination of MgO and Se NPs showed more beneficial effects in reducing the toxicity of DZ. Cotreatment of PaTu cell lines with MgO and Se NPs counteracts the toxicity of DZ on insulin-producing cells. PMID:27920530

  5. Transforming Growth Factor-β Signaling Pathway Activation in Keratoconus

    Science.gov (United States)

    ENGLER, CHRISTOPH; CHAKRAVARTI, SHUKTI; DOYLE, JEFFERSON; EBERHART, CHARLES G.; MENG, HUAN; STARK, WALTER J.; KELLIHER, CLARE; JUN, ALBERT S.

    2011-01-01

    PURPOSE To assess the presence of transforming growth factor-β (TGFβ) pathway markers in the epithelium of keratoconus patient corneas. DESIGN Retrospective, comparative case series of laboratory specimens. METHODS Immunohistochemistry results for TGFβ2, total TGFβ, mothers against decacentaplegic homolog (Smad) 2, and phosphorylated Smad2 was performed on formalin-fixed, paraffin-embedded sections of keratoconus patient corneas and normal corneas from human autopsy eyes. Keratoconus patient corneas were divided in two groups, depending on their severity based on keratometer readings and pachymetry. Autopsy controls were age-matched with the keratoconus cases. Immunohistochemistry signal quantification was performed using automated software. Real-time reverse-transcriptase polymerase chain reaction was performed on total ribonucleic acid of epithelium of keratoconus patient corneas and autopsy control corneas. RESULTS Immunohistochemistry quantification showed a significant increase in mean signal in the group of severe keratoconus cases compared with normal corneas for TGFβ2 and phosphorylated Smad2 (P keratoconus cases versus the autopsy controls. Reverse-transcriptase polymerase chain reaction exhibited elevated messenger ribonucleic acid levels of Smad2 and TGFβ2 in severe keratoconus corneal epithelium. CONCLUSIONS This work shows increased TGFβ pathway markers in severe keratoconus cases and provides the rationale for investigating TGFβ signaling further in the pathophysiology of keratoconus. PMID:21310385

  6. Myocardial Ablation of G Protein-Coupled Receptor Kinase 2 (GRK2 Decreases Ischemia/Reperfusion Injury through an Anti-Intrinsic Apoptotic Pathway.

    Directory of Open Access Journals (Sweden)

    Qian Fan

    Full Text Available Studies from our lab have shown that decreasing myocardial G protein-coupled receptor kinase 2 (GRK2 activity and expression can prevent heart failure progression after myocardial infarction. Since GRK2 appears to also act as a pro-death kinase in myocytes, we investigated the effect of cardiomyocyte-specific GRK2 ablation on the acute response to cardiac ischemia/reperfusion (I/R injury. To do this we utilized two independent lines of GRK2 knockout (KO mice where the GRK2 gene was deleted in only cardiomyocytes either constitutively at birth or in an inducible manner that occurred in adult mice prior to I/R. These GRK2 KO mice and appropriate control mice were subjected to a sham procedure or 30 min of myocardial ischemia via coronary artery ligation followed by 24 hrs reperfusion. Echocardiography and hemodynamic measurements showed significantly improved post-I/R cardiac function in both GRK2 KO lines, which correlated with smaller infarct sizes in GRK2 KO mice compared to controls. Moreover, there was significantly less TUNEL positive myocytes, less caspase-3, and -9 but not caspase-8 activities in GRK2 KO mice compared to control mice after I/R injury. Of note, we found that lowering cardiac GRK2 expression was associated with significantly lower cytosolic cytochrome C levels in both lines of GRK2 KO mice after I/R compared to corresponding control animals. Mechanistically, the anti-apoptotic effects of lowering GRK2 expression were accompanied by increased levels of Bcl-2, Bcl-xl, and increased activation of Akt after I/R injury. These findings were reproduced in vitro in cultured cardiomyocytes and GRK2 mRNA silencing. Therefore, lowering GRK2 expression in cardiomyocytes limits I/R-induced injury and improves post-ischemia recovery by decreasing myocyte apoptosis at least partially via Akt/Bcl-2 mediated mitochondrial protection and implicates mitochondrial-dependent actions, solidifying GRK2 as a pro-death kinase in the heart.

  7. Opposing activities of the Ras and Hippo pathways converge on regulation of YAP protein turnover

    DEFF Research Database (Denmark)

    Hong, Xin; Nguyen, Thanh Hung; Chen, Qingfeng;

    2014-01-01

    Cancer genomes accumulate numerous genetic and epigenetic modifications. Yet, human cellular transformation can be accomplished by a few genetically defined elements. These elements activate key pathways required to support replicative immortality and anchorage independent growth, a predictor of ...

  8. Activation of the jasmonic acid plant defence pathway alters the composition of rhizosphere bacterial communities.

    Science.gov (United States)

    Carvalhais, Lilia C; Dennis, Paul G; Badri, Dayakar V; Tyson, Gene W; Vivanco, Jorge M; Schenk, Peer M

    2013-01-01

    Jasmonic acid (JA) signalling plays a central role in plant defences against necrotrophic pathogens and herbivorous insects, which afflict both roots and shoots. This pathway is also activated following the interaction with beneficial microbes that may lead to induced systemic resistance. Activation of the JA signalling pathway via application of methyl jasmonate (MeJA) alters the composition of carbon containing compounds released by roots, which are implicated as key determinants of rhizosphere microbial community structure. In this study, we investigated the influence of the JA defence signalling pathway activation in Arabidopsis thaliana on the structure of associated rhizosphere bacterial communities using 16S rRNA gene amplicon pyrosequencing. Application of MeJA did not directly influence bulk soil microbial communities but significant changes in rhizosphere community composition were observed upon activation of the jasmonate signalling pathway. Our results suggest that JA signalling may mediate plant-bacteria interactions in the soil upon necrotrophic pathogen and herbivorous insect attacks.

  9. Blockage of both the extrinsic and intrinsic pathways of diazinon-induced apoptosis in PaTu cells by magnesium oxide and selenium nanoparticles

    Directory of Open Access Journals (Sweden)

    Shiri M

    2016-11-01

    Full Text Available Mahdi Shiri,1,2,* Mona Navaei-Nigjeh,1,3,* Maryam Baeeri,1 Mahban Rahimifard,1 Hossein Mahboudi,4 Ahmad Reza Shahverdi,5 Abbas Kebriaeezadeh,1 Mohammad Abdollahi1,6,7 1Department of Toxicology and Pharmacology, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Tehran University of Medical Sciences, 2School of Medicine, Artesh University of Medical Sciences, 3Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran; 4Department of Biotechnology, Faculty of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran; 5Department of Biotechnology, Faculty of Pharmacy and Biotechnology Research Center, 6Toxicology Interest Group, USERN, 7Endocrinology & Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran *These authors contributed equally to this work Abstract: Diazinon (DZ is an organophosphorus insecticide that acts as an acetylcholinesterase inhibitor. It is important to note that it can induce oxidative stress, lipid peroxidation, diabetic disorders, and cytotoxicity. Magnesium oxide (MgO and selenium nanoparticles (Se NPs showed promising protection against oxidative stress, lipid peroxidation, cytotoxicity, and diabetic disorders. Therefore, this study was conducted to explore the possible protective mechanisms of MgO and Se NPs against DZ-induced cytotoxicity in PaTu cell line. Cytotoxicity of DZ, in the presence or absence of effective doses of MgO and Se NPs, was determined in human pancreatic cancer cell line (PaTu cells after 24 hours of exposure by using mitochondrial activity and mitochondrial membrane potential assays. Then, the insulin, proinsulin, and C-peptide release; caspase-3 and -9 activities; and total thiol molecule levels were assessed. Determination of cell viability, including apoptotic and necrotic cells, was assessed via acridine orange/ethidium bromide double

  10. DMPD: Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17502339 Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation...T, Toll-like receptor, and ITAM-dependent pathways inmacrophage activation. Authors Hu X, Chen J, Wang L, Iv...ivation. PubmedID 17502339 Title Crosstalk among Jak-STA...May 14. (.png) (.svg) (.html) (.csml) Show Crosstalk among Jak-STAT, Toll-like receptor, and ITAM-dependent pathways inmacrophage act

  11. The Keap1-Nrf2 pathway: Mechanisms of activation and dysregulation in cancer

    Directory of Open Access Journals (Sweden)

    Emilia Kansanen

    2013-01-01

    Full Text Available The Keap1-Nrf2 pathway is the major regulator of cytoprotective responses to oxidative and electrophilic stress. Although cell signaling pathways triggered by the transcription factor Nrf2 prevent cancer initiation and progression in normal and premalignant tissues, in fully malignant cells Nrf2 activity provides growth advantage by increasing cancer chemoresistance and enhancing tumor cell growth. In this graphical review, we provide an overview of the Keap1-Nrf2 pathway and its dysregulation in cancer cells. We also briefly summarize the consequences of constitutive Nrf2 activation in cancer cells and how this can be exploited in cancer gene therapy.

  12. Antibody constant region peptides can display immunomodulatory activity through activation of the Dectin-1 signalling pathway.

    Directory of Open Access Journals (Sweden)

    Elena Gabrielli

    Full Text Available We previously reported that a synthetic peptide with sequence identical to a CDR of a mouse monoclonal antibody specific for difucosyl human blood group A exerted an immunomodulatory activity on murine macrophages. It was therapeutic against systemic candidiasis without possessing direct candidacidal properties. Here we demonstrate that a selected peptide, N10K, putatively deriving from the enzymatic cleavage of the constant region (Fc of human IgG(1, is able to induce IL-6 secretion and pIkB-α activation. More importantly, it causes an up-regulation of Dectin-1 expression. This leads to an increased activation of β-glucan-induced pSyk, CARD9 and pIkB-α, and an increase in the production of pro-inflammatory cytokines such as IL-6, IL-12, IL-1β and TNF-α. The increased activation of this pathway coincides with an augmented phagocytosis of non opsonized Candida albicans cells by monocytes. The findings suggest that some Fc-peptides, potentially deriving from the proteolysis of immunoglobulins, may cause an unexpected immunoregulation in a way reminiscent of innate immunity molecules.

  13. Stress and radiation-induced activation of multiple intracellular signaling pathways.

    Science.gov (United States)

    Dent, Paul; Yacoub, Adly; Contessa, Joseph; Caron, Ruben; Amorino, George; Valerie, Kristoffer; Hagan, Michael P; Grant, Steven; Schmidt-Ullrich, Rupert

    2003-03-01

    Exposure of cells to a variety of stresses induces compensatory activations of multiple intracellular signaling pathways. These activations can play critical roles in controlling cell survival and repopulation effects in a stress-specific and cell type-dependent manner. Some stress-induced signaling pathways are those normally activated by mitogens such as the EGFR/RAS/PI3K-MAPK pathway. Other pathways activated by stresses such as ionizing radiation include those downstream of death receptors, including pro-caspases and the transcription factor NFKB. This review will attempt to describe some of the complex network of signals induced by ionizing radiation and other cellular stresses in animal cells, with particular attention to signaling by growth factor and death receptors. This includes radiation-induced signaling via the EGFR and IGFI-R to the PI3K, MAPK, JNK, and p38 pathways as well as FAS-R and TNF-R signaling to pro-caspases and NFKB. The roles of autocrine ligands in the responses of cells and bystander cells to radiation and cellular stresses will also be discussed. Based on the data currently available, it appears that radiation can simultaneously activate multiple signaling pathways in cells. Reactive oxygen and nitrogen species may play an important role in this process by inhibiting protein tyrosine phosphatase activity. The ability of radiation to activate signaling pathways may depend on the expression of growth factor receptors, autocrine factors, RAS mutation, and PTEN expression. In other words, just because pathway X is activated by radiation in one cell type does not mean that pathway X will be activated in a different cell type. Radiation-induced signaling through growth factor receptors such as the EGFR may provide radioprotective signals through multiple downstream pathways. In some cell types, enhanced basal signaling by proto-oncogenes such as RAS may provide a radioprotective signal. In many cell types, this may be through PI3K, in others

  14. Dicer-2-dependent activation of Culex Vago occurs via the TRAF-Rel2 signaling pathway.

    Directory of Open Access Journals (Sweden)

    Prasad N Paradkar

    2014-04-01

    Full Text Available Despite their importance as vectors of human and livestock diseases, relatively little is known about innate antiviral immune pathways in mosquitoes and other insects. Previous work has shown that Culex Vago (CxVago, which is induced and secreted from West Nile virus (WNV-infected mosquito cells, acts as a functional homolog of interferon, by activating Jak-STAT pathway and limiting virus replication in neighbouring cells. Here we describe the Dicer-2-dependent pathway leading to WNV-induced CxVago activation. Using a luciferase reporter assay, we show that a NF-κB-like binding site in CxVago promoter region is conserved in mosquito species and is responsible for induction of CxVago expression following WNV infection. Using dsRNA-based gene knockdown, we show that the NF-κB ortholog, Rel2, plays significant role in the signaling pathway that activates CxVago in mosquito cells in vitro and in vivo. Using similar approaches, we also show that TRAF, but not TRAF-3, is involved in activation of Rel2 after viral infection. Overall the study shows that a conserved signaling pathway, which is similar to mammalian interferon activation pathway, is responsible for the induction and antiviral activity of CxVago.

  15. Dicer-2-dependent activation of Culex Vago occurs via the TRAF-Rel2 signaling pathway.

    Science.gov (United States)

    Paradkar, Prasad N; Duchemin, Jean-Bernard; Voysey, Rhonda; Walker, Peter J

    2014-04-01

    Despite their importance as vectors of human and livestock diseases, relatively little is known about innate antiviral immune pathways in mosquitoes and other insects. Previous work has shown that Culex Vago (CxVago), which is induced and secreted from West Nile virus (WNV)-infected mosquito cells, acts as a functional homolog of interferon, by activating Jak-STAT pathway and limiting virus replication in neighbouring cells. Here we describe the Dicer-2-dependent pathway leading to WNV-induced CxVago activation. Using a luciferase reporter assay, we show that a NF-κB-like binding site in CxVago promoter region is conserved in mosquito species and is responsible for induction of CxVago expression following WNV infection. Using dsRNA-based gene knockdown, we show that the NF-κB ortholog, Rel2, plays significant role in the signaling pathway that activates CxVago in mosquito cells in vitro and in vivo. Using similar approaches, we also show that TRAF, but not TRAF-3, is involved in activation of Rel2 after viral infection. Overall the study shows that a conserved signaling pathway, which is similar to mammalian interferon activation pathway, is responsible for the induction and antiviral activity of CxVago.

  16. Mammalian mitogen-activated protein kinase pathways are regulated through formation of specific kinase-activator complexes.

    Science.gov (United States)

    Zanke, B W; Rubie, E A; Winnett, E; Chan, J; Randall, S; Parsons, M; Boudreau, K; McInnis, M; Yan, M; Templeton, D J; Woodgett, J R

    1996-11-22

    Mammalian cells contain at least three signaling systems which are structurally related to the mitogen-activated protein kinase (MAPK) pathway. Growth factors acting through Ras primarily stimulate the Raf/MEK/MAPK cascade of protein kinases. In contrast, many stress-related signals such as heat shock, inflammatory cytokines, and hyperosmolarity induce the MEKK/SEK(MKK4)/SAPK(JNK) and/or the MKK3 or MKK6/p38(hog) pathways. Physiological agonists of these pathway types are either qualitatively or quantitatively distinct, suggesting few common proximal signaling elements, although past studies performed in vitro, or in cells using transient over-expression, reveal interaction between the components of all three pathways. These studies suggest a high degree of cross-talk apparently not seen in vivo. We have examined the possible molecular basis of the differing agonist profiles of these three MAPK pathways. We report preferential association between MAP kinases and their activators in eukaryotic cells. Furthermore, using the yeast 2-hybrid system, we show that association between these components can occur independent of additional eukaryotic proteins. We show that SAPK(JNK) or p38(hog) activation is specifically impaired by co-expression of cognate dominant negative MAP kinase kinase mutants, demonstrating functional specificity at this level. Further divergence and insulation of the stress pathways occurs proximal to the MAPK kinases since activation of the MAPK kinase kinase MEKK results in SAPK(JNK) activation but does not cause p38(hog) phosphorylation. Therefore, in intact cells, the three MAPK pathways may be independently regulated and their components show specificity in their interaction with cognate cascade members. The degree of intermolecular specificity suggests that mammalian MAPK signaling pathways may remain distinct without the need for specific scaffolding proteins to sequester components of individual pathways.

  17. Lactobacillus bulgaricus OLL1181 activates the aryl hydrocarbon receptor pathway and inhibits colitis.

    Science.gov (United States)

    Takamura, Takeyuki; Harama, Daisuke; Fukumoto, Suguru; Nakamura, Yuki; Shimokawa, Naomi; Ishimaru, Kayoko; Ikegami, Shuji; Makino, Seiya; Kitamura, Masanori; Nakao, Atsuhito

    2011-10-01

    Increasing evidence suggests that the aryl hydrocarbon receptor (AhR) pathway has an important role in the regulation of inflammatory responses. Most recently, we have shown that the activation of the AhR pathway by a potent AhR agonist inhibits the development of dextran sodium sulfate (DSS)-induced colitis, a model of human ulcerative colitis, by the induction of prostaglandin E2 (PGE2) in the large intestine. Because several strains of probiotic lactic acid bacteria have been reported to inhibit DSS-induced colitis by unidentified mechanisms, we hypothesized that particular strains of lactic acid bacterium might have the potential to activate the AhR pathway, thereby inhibiting DSS-induced colitis. This study investigated whether there are specific lactic acid bacterial strains that can activate the AhR pathway, and if so, whether this AhR-activating potential is associated with suppression of DSS-induced colitis. By using AhR signaling reporter cells, we found that Lactobacillus bulgaricus OLL1181 had the potential to activate the AhR pathway. OLL1181 also induced the mRNA expression of cytochrome P450 family 1A1 (CYP1A1), a target gene of the AhR pathway, in human colon cells, which was inhibited by the addition of an AhR antagonist, α-naphthoflavon (αNF). In addition, mice treated orally with OLL1181 showed an increase in CYP1A1 mRNA expression in the large intestine and amelioration of DSS-induced colitis. Thus, OLL1181 can induce activation of the intestinal AhR pathway and inhibit DSS-induced colitis in mice. This strain of lactic acid bacterium has therefore the potential to activate the AhR pathway, which may be able to suppress colitis.

  18. Identifying the neural substrates of intrinsic motivation during task performance.

    Science.gov (United States)

    Lee, Woogul; Reeve, Johnmarshall

    2017-06-21

    Intrinsic motivation is the inherent tendency to seek out novelty and challenge, to explore and investigate, and to stretch and extend one's capacities. When people imagine performing intrinsically motivating tasks, they show heightened anterior insular cortex (AIC) activity. To fully explain the neural system of intrinsic motivation, however, requires assessing neural activity while people actually perform intrinsically motivating tasks (i.e., while answering curiosity-inducing questions or solving competence-enabling anagrams). Using event-related functional magnetic resonance imaging, we found that the neural system of intrinsic motivation involves not only AIC activity, but also striatum activity and, further, AIC-striatum functional interactions. These findings suggest that subjective feelings of intrinsic satisfaction (associated with AIC activations), reward processing (associated with striatum activations), and their interactions underlie the actual experience of intrinsic motivation. These neural findings are consistent with the conceptualization of intrinsic motivation as the pursuit and satisfaction of subjective feelings (interest and enjoyment) as intrinsic rewards.

  19. Catechin-induced activation of the LKB1/AMP-activated protein kinase pathway.

    Science.gov (United States)

    Murase, Takatoshi; Misawa, Koichi; Haramizu, Satoshi; Hase, Tadashi

    2009-07-01

    Catechins are abundant in green tea and induce a variety of biologic actions, including anti-cancer, anti-obesity, and anti-diabetes effects, and their clinical application has been widely investigated. To clarify the underlying molecular mechanisms of these actions, we examined the effect of catechins on AMP-activated protein kinase (AMPK) in cultured cells and in mice. In Hepa 1-6, L6, and 3T3-L1 cells, epigallocatechin gallate (EGCG) induced increases in AMPKalpha and the downstream target acetyl-CoA carboxylase (ACC) phosphorylation, and AMPKalpha activity. Analysis of the molecular specificity of eight naturally occurring catechins revealed that catechins with a gallocatechin moiety or a galloyl residue act as AMPK activators. In addition, phosphorylation of LKB1, which is a tumor-suppressor protein and a major AMPK-kinase, was increased by catechin treatment. EGCG-induced phosphorylation of LKB1 and AMPKalpha was suppressed by treatment with catalase, suggesting that reactive oxygen species are involved in EGCG-induced activation of the LKB1/AMPK pathway. Oral administration of EGCG (200mg/kg body weight) to BALB/c mice induced an increase in AMPKalpha activity in the liver concomitant with a significant increase in AMPKalpha and ACC phosphorylation. EGCG administration also increased oxygen consumption and fat oxidation, as determined by indirect calorimetry. These findings suggest that multiple effects of catechins, including anti-obesity and anti-cancer effects, are mediated, at least in part, by the activation of LKB1/AMPK in various tissues, and that these effects vary according to the catechin structure.

  20. Intrinsically Disordered Energy Landscapes

    Science.gov (United States)

    Chebaro, Yassmine; Ballard, Andrew J.; Chakraborty, Debayan; Wales, David J.

    2015-05-01

    Analysis of an intrinsically disordered protein (IDP) reveals an underlying multifunnel structure for the energy landscape. We suggest that such ‘intrinsically disordered’ landscapes, with a number of very different competing low-energy structures, are likely to characterise IDPs, and provide a useful way to address their properties. In particular, IDPs are present in many cellular protein interaction networks, and several questions arise regarding how they bind to partners. Are conformations resembling the bound structure selected for binding, or does further folding occur on binding the partner in a induced-fit fashion? We focus on the p53 upregulated modulator of apoptosis (PUMA) protein, which adopts an -helical conformation when bound to its partner, and is involved in the activation of apoptosis. Recent experimental evidence shows that folding is not necessary for binding, and supports an induced-fit mechanism. Using a variety of computational approaches we deduce the molecular mechanism behind the instability of the PUMA peptide as a helix in isolation. We find significant barriers between partially folded states and the helix. Our results show that the favoured conformations are molten-globule like, stabilised by charged and hydrophobic contacts, with structures resembling the bound state relatively unpopulated in equilibrium.

  1. Molecular pathways: targeting MALT1 paracaspase activity in lymphoma.

    Science.gov (United States)

    Fontán, Lorena; Melnick, Ari

    2013-12-15

    MALT1 mediates the activation of NF-κB in response to antigen receptor signaling. MALT1, in association with BCL10 and CARD11, functions as a scaffolding protein to activate the inhibitor of IκB kinase (IKK) complex. In addition, MALT1 is a paracaspase that targets key proteins in a feedback loop mediating termination of the NF-κB response, thus promoting activation of NF-κB signaling. Activated B-cell subtype of diffuse large B-cell lymphomas (ABC-DLBCL), which tend to be more resistant to chemotherapy, are often biologically dependent on MALT1 activity. Newly developed MALT1 small-molecule inhibitors suppress the growth of ABC-DLBCLs in vitro and in vivo. This review highlights the recent advances in the normal and disease-related functions of MALT1. Furthermore, recent progress targeting MALT1 proteolytic activity raises the possibility of deploying MALT1 inhibitors for the treatment of B-cell lymphomas and perhaps autoimmune diseases that involve increased B- or T-cell receptor signaling.

  2. Hedgehog pathway activity in the LADY prostate tumor model

    Directory of Open Access Journals (Sweden)

    Kasper Susan

    2007-03-01

    Full Text Available Abstract Background Robust Hedgehog (Hh signaling has been implicated as a common feature of human prostate cancer and an important stimulus of tumor growth. The role of Hh signaling has been studied in several xenograft tumor models, however, the role of Hh in tumor development in a transgenic prostate cancer model has never been examined. Results We analyzed expression of Hh pathway components and conserved Hh target genes along with progenitor cell markers and selected markers of epithelial differentiation during tumor development in the LADY transgenic mouse model. Tumor development was associated with a selective increase in Ihh expression. In contrast Shh expression was decreased. Expression of the Hh target Patched (Ptc was significantly decreased while Gli1 expression was not significantly altered. A survey of other relevant genes revealed significant increases in expression of Notch-1 and Nestin together with decreased expression of HNF3a/FoxA1, NPDC-1 and probasin. Conclusion Our study shows no evidence for a generalized increase in Hh signaling during tumor development in the LADY mouse. It does reveal a selective increase in Ihh expression that is associated with increased expression of progenitor cell markers and decreased expression of terminal differentiation markers. These data suggest that Ihh expression may be a feature of a progenitor cell population that is involved in tumor development.

  3. TOR pathway activation in Zea mays L. tissues: conserved function between animal and plant kingdoms.

    Science.gov (United States)

    Garrocho-Villegas, Verónica; de Jiménez, Estela Sánchez

    2012-06-01

    In most non-photosynthetic eukaryotes it has been demonstrated a conserved signal transduction pathway, namely TOR-S6K, that coordinates growth and cell proliferation. This pathway targets the translational apparatus to induce selective translation of ribosomal mRNAs as well as stimulate the cell cycle transition through the G1/S phase. Thus, by activation of this pathway through environmental signals, nutrients, stress, or specific growth factors, such as insulin or insulin-like growth factors (IGF), this pathway allows organisms to regulate growth and cell division. In plants, evidence has shown that TOR protein has been highly conserved through evolution, being involved in growth and cell proliferation control as well. Particularly in maize, a peptide named ZmIGF has been found in actively growing tissues. It targets the maize TOR pathway at the same extent as insulin and, by doing so it induces growth, as well as ribosomal proteins and DNA synthesis. Thus, higher metazoans and plants seem to conserve similar biochemical paths to regulate cell growth through equivalent targets that conduce to activation of the TOR-S6K pathway. Recent research shows evidence that supports this proposal by uncovering the ZmIGF receptor in maize, providing further means for analyzing the role of the conserved TOR signaling pathway in this plant.

  4. Molecular mechanism of cellular reception of ionizing radiation and of activation of signal transduction pathway

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Keiji [Nagasaki Univ. (Japan). Faculty of Pharmaceutical Sciences

    1997-03-01

    The author reviewed what in cells receives ionizing radiation as a stress and which signal transduction pathway is activated to induce the stress reaction in the following order: Activation of protein kinase C (PKC) pathway by radiation, activation of MAP kinase superfamily by radiation, induction of p53 function by radiation, and radiation exposure and stress reaction pathway. Conclusion was as follows: Cellular receptors to radiation can be cell membrane and DNA. Membrane reception of radiation induces activation of tyrosine kinase and sphingomyelinase, which resulting in activation of PKC- and MAP kinase-mediated signal transduction. The signal generated in the nucleus participates in regulation of cell cycle and in DNA repair. Therefore, it seems that irradiation of ionizing radiation gives energy to various cellular receptor sites as well as DNA, which generate various independent signals to be transduced and accumulated in the nucleus, and leading to cellular response. (K.H.). 63 refs.

  5. Older but still fluent? Insights from the intrinsically active baseline configuration of the aging brain using a data driven graph-theoretical approach.

    Science.gov (United States)

    Muller, Angela M; Mérillat, Susan; Jäncke, Lutz

    2016-02-15

    A major part of our knowledge about the functioning of the aging brain comes from task-induced activation paradigms. However, the aging brain's intrinsic functional organization may be already a limiting factor for the outcome of an actual behavior. In order to get a better understanding of how this functional baseline configuration of the aging brain may affect cognitive performance, we analyzed task-free fMRI data of older 186 participants (mean age=70.4, 97 female) and their performance data in verbal fluency: First, we conducted an intrinsic connectivity contrast analysis (ICC) for the purpose of evaluating the brain regions whose degree of connectedness was significantly correlated with fluency performance. Secondly, using connectivity analyses we investigated how the clusters from the ICC functionally related to the other major resting-state networks. Apart from the importance of intact fronto-parietal long-range connections, the preserved capacity of the DMN for a finely attuned interaction with the executive-control network and the language network seems to be crucial for successful verbal fluency performance in older people. We provide further evidence that the right frontal regions might be more prominently affected by age-related decline.

  6. The Biases of Optical Line-Ratio Selection for Active Galactic Nuclei, and the Intrinsic Relationship between Black Hole Accretion and Galaxy Star Formation

    CERN Document Server

    Trump, Jonathan R; Zeimann, Gregory R; Luck, Cuyler; Bridge, Joanna S; Grier, Catherine J; Hagen, Alex; Juneau, Stephanie; Montero-Dorta, Antonio; Rosario, David J; Brandt, W Niel; Ciardullo, Robin; Schneider, Donald P

    2015-01-01

    We use 317,000 emission-line galaxies from the Sloan Digital Sky Survey to investigate line-ratio selection of active galactic nuclei (AGNs). In particular, we demonstrate that "star formation dilution" by HII regions causes a significant bias against AGN selection in low-mass, blue, star-forming, disk-dominated galaxies. This bias is responsible for the observed preference of AGNs among high-mass, green, moderately star-forming, bulge-dominated hosts. We account for the bias and simulate the intrinsic population of emission-line AGNs using a physically-motivated Eddington ratio distribution, intrinsic AGN narrow line region line ratios, a luminosity-dependent Lbol/L[OIII] bolometric correction, and the observed Mbh-sigma relation. These simulations indicate that, in massive (log(M*/Msun) > 10) galaxies, AGN accretion is correlated with specific star formation rate but is otherwise uniform with stellar mass. There is some hint of lower black hole occupation in low-mass (log(M*/Msun) < 10) hosts, although o...

  7. Glioblastoma subclasses can be defined by activity among signal transduction pathways and associated genomic alterations.

    Directory of Open Access Journals (Sweden)

    Cameron Brennan

    Full Text Available BACKGROUND: Glioblastoma multiforme (GBM is an umbrella designation that includes a heterogeneous group of primary brain tumors. Several classification strategies of GBM have been reported, some by clinical course and others by resemblance to cell types either in the adult or during development. From a practical and therapeutic standpoint, classifying GBMs by signal transduction pathway activation and by mutation in pathway member genes may be particularly valuable for the development of targeted therapies. METHODOLOGY/PRINCIPAL FINDINGS: We performed targeted proteomic analysis of 27 surgical glioma samples to identify patterns of coordinate activation among glioma-relevant signal transduction pathways, then compared these results with integrated analysis of genomic and expression data of 243 GBM samples from The Cancer Genome Atlas (TCGA. In the pattern of signaling, three subclasses of GBM emerge which appear to be associated with predominance of EGFR activation, PDGFR activation, or loss of the RAS regulator NF1. The EGFR signaling class has prominent Notch pathway activation measured by elevated expression of Notch ligands, cleaved Notch receptor, and downstream target Hes1. The PDGF class showed high levels of PDGFB ligand and phosphorylation of PDGFRbeta and NFKB. NF1-loss was associated with lower overall MAPK and PI3K activation and relative overexpression of the mesenchymal marker YKL40. These three signaling classes appear to correspond with distinct transcriptomal subclasses of primary GBM samples from TCGA for which copy number aberration and mutation of EGFR, PDGFRA, and NF1 are signature events. CONCLUSIONS/SIGNIFICANCE: Proteomic analysis of GBM samples revealed three patterns of expression and activation of proteins in glioma-relevant signaling pathways. These three classes are comprised of roughly equal numbers showing either EGFR activation associated with amplification and mutation of the receptor, PDGF-pathway activation

  8. Saturated fatty acids activate TLR-mediated proinflammatory signaling pathways.

    Science.gov (United States)

    Huang, Shurong; Rutkowsky, Jennifer M; Snodgrass, Ryan G; Ono-Moore, Kikumi D; Schneider, Dina A; Newman, John W; Adams, Sean H; Hwang, Daniel H

    2012-09-01

    Toll-like receptor 4 (TLR4) and TLR2 were shown to be activated by saturated fatty acids (SFAs) but inhibited by docosahexaenoic acid (DHA). However, one report suggested that SFA-induced TLR activation in cell culture systems is due to contaminants in BSA used for solubilizing fatty acids. This report raised doubt about proinflammatory effects of SFAs. Our studies herein demonstrate that sodium palmitate (C16:0) or laurate (C12:0) without BSA solubilization induced phosphorylation of inhibitor of nuclear factor-κB α, c-Jun N-terminal kinase (JNK), p44/42 mitogen-activated-kinase (ERK), and nuclear factor-κB subunit p65, and TLR target gene expression in THP1 monocytes or RAW264.7 macrophages, respectively, when cultured in low FBS (0.25%) medium. C12:0 induced NFκB activation through TLR2 dimerized with TLR1 or TLR6, and through TLR4. Because BSA was not used in these experiments, contaminants in BSA have no relevance. Unlike in suspension cells (THP-1), BSA-solubilized C16:0 instead of sodium C16:0 is required to induce TLR target gene expression in adherent cells (RAW264.7). C16:0-BSA transactivated TLR2 dimerized with TLR1 or TLR6 and through TLR4 as seen with C12:0. These results and additional studies with the LPS sequester polymixin B and in MyD88(-/-) macrophages indicated that SFA-induced activation of TLR2 or TLR4 is a fatty acid-specific effect, but not due to contaminants in BSA or fatty acid preparations.

  9. HIF-1α Activation Attenuates IL-6 and TNF-α Pathways in Hippocampus of Rats Following Transient Global Ischemia

    Directory of Open Access Journals (Sweden)

    Jihong Xing

    2016-07-01

    Full Text Available Background/Aims: This study was to examine the role played by hypoxia inducible factor-1 (HIF-1α in regulating pro-inflammatory cytokines (PICs pathway in the rat hippocampus after cardiac arrest (CA induced-transient global ischemia followed by cardiopulmonary resuscitation (CPR. Those PICs include interleukin-1β (IL-1β, interleukin-6 (IL-6 and tumor necrosis factor-α (TNF-α. Methods: A rat model of CA induced by asphyxia was used in the current study. Following CPR, the hippocampus CA1 region was obtained for ELISA to determine the levels of HIF-1α and PICs; and Western Blot analysis to determine the protein levels of PIC receptors. Results: Our data show that IL-1β, IL-6 and TNF-α were significant elevated in the hippocampus after CPR as compared with control group. This was companied with increasing of HIF-1α and the time courses for HIF-1α and PICs were similar. In addition, PIC receptors, namely IL-1R, IL-6R and TNFR1 were upregulated in CA rats. Also, stimulation of HIF-1α by systemic administration of ML228, HIF-1α activator, significantly attenuated the amplified IL-6/IL-6R and TNF-α /TNFR1 pathway in the hippocampus of CA rats, but did not modify IL-1β and its receptor. Moreover, ML228 attenuated upregulated expression of Caspase-3 indicating cell apoptosis evoked by CA. Conclusion: Transient global ischemia induced by CA increases the levels of IL-1β, IL-6 and TNF-α and thereby leads to enhancement in their respective receptor in the rat hippocampus. Stabilization of HIF-1α plays a role in attenuating amplified expression IL-6R, TNFR1 and Caspase-3 in the processing of transient global ischemia. Results of our study suggest that PICs contribute to cerebral injuries evoked by transient global ischemia and in this pathophysiological process activation of HIF-1α improves tissues against ischemic injuries. Our data revealed specific signaling pathways in alleviating CA-evoked global cerebral ischemia by elucidating that

  10. CKIP-1 is an intrinsic negative regulator of T-cell activation through an interaction with CARMA1.

    Directory of Open Access Journals (Sweden)

    Takashi Sakamoto

    Full Text Available The transcription factor NF-κB plays a key regulatory role in lymphocyte activation and generation of immune response. Stimulation of T cell receptor (TCR induces phosphorylation of CARMA1 by PKCθ, resulting in formation of CARMA1-Bcl10-MALT1 (CBM complex at lipid rafts and subsequently leading to NF-κB activation. While many molecular events leading to NF-κB activation have been reported, it is less understood how this activation is negatively regulated. We performed a cell-based screening for negative regulators of TCR-mediated NF-κB activation, using mutagenesis and complementation cloning strategies. Here we show that casein kinase-2 interacting protein-1 (CKIP-1 suppresses PKCθ-CBM-NF-κB signaling. We found that CKIP-1 interacts with CARMA1 and competes with PKCθ for association. We further confirmed that a PH domain of CKIP-1 is required for association with CARMA1 and its inhibitory effect. CKIP-1 represses NF-κB activity in unstimulated cells, and inhibits NF-κB activation induced by stimulation with PMA or constitutively active PKCθ, but not by stimulation with TNFα. Interestingly, CKIP-1 does not inhibit NF-κB activation induced by CD3/CD28 costimulation, which caused dissociation of CKIP-1 from lipid rafts. These data suggest that CKIP-1 contributes maintenance of a resting state on NF-κB activity or prevents T cells from being activated by inadequate signaling. In conclusion, we demonstrate that CKIP-1 interacts with CARMA1 and has an inhibitory effect on PKCθ-CBM-NF-κB signaling.

  11. Evolution of a new chlorophyll metabolic pathway driven by the dynamic changes in enzyme promiscuous activity.

    Science.gov (United States)

    Ito, Hisashi; Tanaka, Ayumi

    2014-03-01

    Organisms generate an enormous number of metabolites; however, the mechanisms by which a new metabolic pathway is acquired are unknown. To elucidate the importance of promiscuous enzyme activity for pathway evolution, the catalytic and substrate specificities of Chl biosynthetic enzymes were examined. In green plants, Chl a and Chl b are interconverted by the Chl cycle: Chl a is hydroxylated to 7-hydroxymethyl chlorophyll a followed by the conversion to Chl b, and both reactions are catalyzed by chlorophyllide a oxygenase. Chl b is reduced to 7-hydroxymethyl chlorophyll a by Chl b reductase and then converted to Chl a by 7-hydroxymethyl chlorophyll a reductase (HCAR). A phylogenetic analysis indicated that HCAR evolved from cyanobacterial 3,8-divinyl chlorophyllide reductase (DVR), which is responsible for the reduction of an 8-vinyl group in the Chl biosynthetic pathway. In addition to vinyl reductase activity, cyanobacterial DVR also has Chl b reductase and HCAR activities; consequently, three of the four reactions of the Chl cycle already existed in cyanobacteria, the progenitor of the chloroplast. During the evolution of cyanobacterial DVR to HCAR, the HCAR activity, a promiscuous reaction of cyanobacterial DVR, became the primary reaction. Moreover, the primary reaction (vinyl reductase activity) and some disadvantageous reactions were lost, but the neutral promiscuous reaction (NADH dehydrogenase) was retained in both DVR and HCAR. We also show that a portion of the Chl c biosynthetic pathway already existed in cyanobacteria. We discuss the importance of dynamic changes in promiscuous activity and of the latent pathways for metabolic evolution.

  12. [New strategy to promote adult spinal cord regeneration: enhance adult neurons' intrinsic growth capability].

    Science.gov (United States)

    Yang, Ping

    2009-01-01

    Injured adult spinal cord neurons are usually unable to regenerate their axons due to the inhibitory environment and low intrinsic regenerative capability. One of the main strategies to promote spinal cord regeneration is blocking and/or neutralizing the inhibitory factors or their common inhibitory signal pathway. However, overcoming inhibition alone is insufficient to cause extensive regeneration when neurons' intrinsic growth state has not been activated. Therefore, it becomes one of the most interested targets for promoting spinal cord regeneration that how to enhance adult neurons' intrinsic growth capability, such as elevating adult neuron cAMP/PKA level, blocking Rho/ROCK pathway, modulating transcriptional factors etc., such that they no longer response to inhibitory environment. In this paper we will review the current research findings and recent progresses in this field.

  13. Activation of the Wnt Pathway by Mycobacterium tuberculosis: A Wnt–Wnt Situation

    Science.gov (United States)

    Villaseñor, Tomás; Madrid-Paulino, Edgardo; Maldonado-Bravo, Rafael; Urbán-Aragón, Antonio; Pérez-Martínez, Leonor; Pedraza-Alva, Gustavo

    2017-01-01

    Mycobacterium tuberculosis (M. tuberculosis), an intracellular pathogenic Gram-positive bacterium, is the cause of tuberculosis (TB), a major worldwide human infectious disease. The innate immune system is the first host defense against M. tuberculosis. The recognition of this pathogen is mediated by several classes of pattern recognition receptors expressed on the host innate immune cells, including Toll-like receptors, Nod-like receptors, and C-type lectin receptors like Dectin-1, the Mannose receptor, and DC-SIGN. M. tuberculosis interaction with any of these receptors activates multiple signaling pathways among which the protein kinase C, the MAPK, and the NFκB pathways have been widely studied. These pathways have been implicated in macrophage invasion, M. tuberculosis survival, and impaired immune response, thus promoting a successful infection and disease. Interestingly, the Wnt signaling pathway, classically regarded as a pathway involved in the control of cell proliferation, migration, and differentiation in embryonic development, has recently been involved in immunoregulatory mechanisms in infectious and inflammatory diseases, such as TB, sepsis, psoriasis, rheumatoid arthritis, and atherosclerosis. In this review, we present the current knowledge supporting a role for the Wnt signaling pathway during macrophage infection by M. tuberculosis and the regulation of the immune response against M. tuberculosis. Understanding the cross talk between different signaling pathways activated by M. tuberculosis will impact on the search for new therapeutic targets to fuel the rational design of drugs aimed to restore the immunological response against M. tuberculosis. PMID:28203237

  14. Quercitrin attenuates osteoporosis in ovariectomized rats by regulating mitogen-activated protein kinase (MAPK) signaling pathways.

    Science.gov (United States)

    Xing, Li-Zhi; Ni, Huai-Jun; Wang, Yu-Ling

    2017-03-13

    MAPK signaling pathways are crucial in regulating osteogenesis, a genetic disorder affecting the bones. Quercitrin, a type of flavonoid, is widely distributed in nature and involved in many pharmacological activities. But its osteoprotective functions and mechanism in osteoporosis are far from being understood clearly. In this paper, the MAPK upregulation was observed in the ovariectomy-induced bone loss. Quercitrin was found to downregulate MAPK signaling pathways and prevent the ovariectomy-induced deterioration of bone mineral density (BMD), trabecular microstructure, and bone mechanical characteristics. In this study, quercitrin was seen to prevent the progression of the postmenopausal osteoporosis among the rats, which may be mediated by the downregulated MAPK signaling pathways.

  15. Intrinsic energy partition in fission

    Directory of Open Access Journals (Sweden)

    Mirea M.

    2013-03-01

    Full Text Available The intrinsic energy partition between two complementary fission fragments is investigated microscopically. The intrinsic excitation energy of fission fragments is dynamically evaluated in terms of the time-dependent pairing equations. These equations are corroborated with two conditions. One of them fixes the number of particles and the other separates the pairing active spaces associated to the two fragments in the vicinity of the scission configuration. The excitation energy in a wide distribution of fission fragments is calculated for the 234U parent nucleus.

  16. Stress and CRF gate neural activation of BDNF in the mesolimbic reward pathway.

    Science.gov (United States)

    Walsh, Jessica J; Friedman, Allyson K; Sun, Haosheng; Heller, Elizabeth A; Ku, Stacy M; Juarez, Barbara; Burnham, Veronica L; Mazei-Robison, Michelle S; Ferguson, Deveroux; Golden, Sam A; Koo, Ja Wook; Chaudhury, Dipesh; Christoffel, Daniel J; Pomeranz, Lisa; Friedman, Jeffrey M; Russo, Scott J; Nestler, Eric J; Han, Ming-Hu

    2014-01-01

    Mechanisms controlling release of brain-derived neurotrophic factor (BDNF) in the mesolimbic dopamine reward pathway remain unknown. We report that phasic optogenetic activation of this pathway increases BDNF amounts in the nucleus accumbens (NAc) of socially stressed mice but not of stress-naive mice. This stress gating of BDNF signaling is mediated by corticotrophin-releasing factor (CRF) acting in the NAc. These results unravel a stress context-detecting function of the brain's mesolimbic circuit.

  17. DMPD: A pervasive role of ubiquitin conjugation in activation and termination ofIkappaB kinase pathways. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15809659 A pervasive role of ubiquitin conjugation in activation and termination of.... PubmedID 15809659 Title A pervasive role of ubiquitin conjugation in activation...IkappaB kinase pathways. Krappmann D, Scheidereit C. EMBO Rep. 2005 Apr;6(4):321-6. (.png) (.svg) (.html) (....csml) Show A pervasive role of ubiquitin conjugation in activation and termination ofIkappaB kinase pathways

  18. Depressed activation of the lectin pathway of complement in hereditary angioedema

    DEFF Research Database (Denmark)

    Varga, L; Széplaki, G; Laki, J

    2008-01-01

    ) in three complement activation pathways. Functional activity of the CP, LP and AP were measured in the sera of 68 adult patients with hereditary angioedema (HAE) and 64 healthy controls. In addition, the level of C1q, MBL, MBL-associated serine protease-2 (MASP-2), C4-, C3- and C1INH was measured...

  19. Inflammation-associated activation of coagulation and immune regulation by the protein C pathway.

    Science.gov (United States)

    Weiler, Hartmut

    2014-05-01

    The inflammation-induced activation of the protein C pathway provides negative feedback inhibition of coagulation and exerts coagulation-independent anti-inflammatory and cytoprotective effects. The balance between these activities of aPC modulates the outcome of diverse inflammatory diseases such as encephalitis, diabetes, and sepsis; and is affected by naturally occurring aPC-resistance of coagulation factor V Leiden.

  20. Determination of alternative pathway of complement activity in mouse serum using rabbit erythrocytes

    NARCIS (Netherlands)

    Dijk, H. van; Rademaker, P.M.; Willers, J.M.N

    1980-01-01

    Rabbit, mouse and sheep erythrocytes expressing different concentrations of membrane sialic acid were used to study possible modes of activation of the alternative complement (C) pathway in mouse, human and guinea pig serum. Mouse erythrocytes activated only human serum, whereas rabbit erythrocytes

  1. Activation of the TOR Signalling Pathway by Glutamine Regulates Insect Fecundity.

    Science.gov (United States)

    Zhai, Yifan; Sun, Zhongxiang; Zhang, Jianqing; Kang, Kui; Chen, Jie; Zhang, Wenqing

    2015-05-29

    The target of rapamycin (TOR) positively controls cell growth in response to nutrients such as amino acids. However, research on the specific nutrients sensed by TOR is limited. Glutamine (Gln), a particularly important amino acid involved in metabolism in organisms, is synthesised and catalysed exclusively by glutamine synthetase (GS), and our previous studies have shown that Gln may regulate fecundity in vivo levels of the brown planthopper (BPH) Nilaparvata lugens. Until now, it has remained unclear whether Gln activates or inhibits the TOR signalling pathway. Here, we performed the combined analyses of iTRAQ (isobaric tags for relative and absolute quantification) and DGE (tag-based digital gene expression) data in N. lugens at the protein and transcript levels after GS RNAi, and we found that 52 pathways overlap, including the TOR pathway. We further experimentally demonstrate that Gln activates the TOR pathway by promoting the serine/threonine protein kinase AKT and inhibiting the 5'AMP-activated protein kinase AMPK phosphorylation activity in the pest. Furthermore, TOR regulates the fecundity of N. lugens probably by mediating vitellogenin (Vg) expression. This work is the first report that Gln activates the TOR pathway in vivo.

  2. Lack of telomerase activity in rabbit bone marrow stromal cells during differentiation along neural pathway

    Institute of Scientific and Technical Information of China (English)

    CHEN Zhen-zhou; XU Ru-xiang; JIANG Xiao-dan; TENG Xiao-hua; LI Gui-tao; ZHOU Yü-xi

    2006-01-01

    Objective: To investigate telomerase activity in rabbit bone marrow stromal cells (BMSCs) during their committed differentiation in vitro along neural pathway and the effect of glial cell line-derived neurotrophic factor (GDNF) on the expression of telomerase.Methods: BMSCs were acquired from rabbit marrow and divided into control group, GDNF (10 ng/ml) group.No. ZL02134314. 4) supplemented with 10% fetal bovine serum (FBS) was used to induce BMSCs differentiation along neural pathway. Fluorescent immunocytochemistry was employed to identify the expressions of Nestin, neuronspecific endase (NSE), and gial fibrillary acidic protein (GFAP). The growth curves of the cells and the status of cell cycles were analyzed, respectively. During the differentiation, telomerase activitys were detected using the telomeric repeat amplification protocol-enzyme-linked immunosorbent assay (TRAP-ELISA).Results: BMSCs were successfully induced to differentiate along neural pathway and expressed specific markers of fetal neural epithelium, mature neuron and glial cells. Telomerase activities were undetectable in BMSCs during differentiation along neural pathway. Similar changes of cell growth curves, cell cycle status and telomerase expression were observed in the two groups.Conclusions: Rabbit BMSCs do not display telomerase activity during differentiation along neural pathway. GDNF shows little impact on proliferation and telomerase activity of BMSCs.

  3. Protein S blocks the extrinsic apoptotic cascade in tissue plasminogen activator/N-methyl D-aspartate-treated neurons via Tyro3-Akt-FKHRL1 signaling pathway

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    Freeman Robert S

    2011-02-01

    Full Text Available Abstract Background Thrombolytic therapy with tissue plasminogen activator (tPA benefits patients with acute ischemic stroke. However, tPA increases the risk for intracerebral bleeding and enhances post-ischemic neuronal injury if administered 3-4 hours after stroke. Therefore, combination therapies with tPA and neuroprotective agents have been considered to increase tPA's therapeutic window and reduce toxicity. The anticoagulant factor protein S (PS protects neurons from hypoxic/ischemic injury. PS also inhibits N-methyl-D-aspartate (NMDA excitotoxicity by phosphorylating Bad and Mdm2 which blocks the downstream steps in the intrinsic apoptotic cascade. To test whether PS can protect neurons from tPA toxicity we studied its effects on tPA/NMDA combined injury which in contrast to NMDA alone kills neurons by activating the extrinsic apoptotic pathway. Neither Bad nor Mdm2 which are PS's targets and control the intrinsic apoptotic pathway can influence the extrinsic cascade. Thus, based on published data one cannot predict whether PS can protect neurons from tPA/NMDA injury by blocking the extrinsic pathway. Neurons express all three TAM (Tyro3, Axl, Mer receptors that can potentially interact with PS. Therefore, we studied whether PS can activate TAM receptors during a tPA/NMDA insult. Results We show that PS protects neurons from tPA/NMDA-induced apoptosis by suppressing Fas-ligand (FasL production and FasL-dependent caspase-8 activation within the extrinsic apoptotic pathway. By transducing neurons with adenoviral vectors expressing the kinase-deficient Akt mutant AktK179A and a triple FKHRL1 Akt phosphorylation site mutant (FKHRL1-TM, we show that Akt activation and Akt-mediated phosphorylation of FKHRL1, a member of the Forkhead family of transcription factors, are critical for FasL down-regulation and caspase-8 inhibition. Using cultured neurons from Tyro3, Axl and Mer mutants, we show that Tyro3, but not Axl and Mer, mediates

  4. Porous Co₃O₄ nanorods-reduced graphene oxide with intrinsic peroxidase-like activity and catalysis in the degradation of methylene blue.

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    Zhang, Zhe; Hao, Jinhui; Yang, Wenshu; Lu, Baoping; Ke, Xi; Zhang, Bailin; Tang, Jilin

    2013-05-01

    A facile two step process was developed for the synthesis of porous Co3O4 nanorods-reduced graphene oxide (PCNG) hybrid materials based on the hydrothermal treatment cobalt acetate tetrahydrate and graphene oxide in a glycerol-water mixed solvent, followed by annealing the intermediate of reduced graphene oxide-supported Co(CO3)0.5(OH)·0.11H2O nanorods in a N2 atmosphere. The morphology and microstructure of the composites were examined by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy and Raman spectroscopy. It is shown that the obtained PCNG have intrinsic peroxidase-like activity. The PCNG are utilized for the catalytic degradation of methylene blue. The good catalytic performance of the composites could be attributed to the synergy between the functions of porous Co3O4 nanorods and reduced graphene oxide.

  5. Repetition priming of motor activity mediated by a central pattern generator: the importance of extrinsic vs. intrinsic program initiators.

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    Siniscalchi, Michael J; Cropper, Elizabeth C; Jing, Jian; Weiss, Klaudiusz R

    2016-10-01

    Repetition priming is characterized by increased performance as a behavior is repeated. Although this phenomenon is ubiquitous, mediating mechanisms are poorly understood. We address this issue in a model system, the feeding network of Aplysia This network generates both ingestive and egestive motor programs. Previous data suggest a chemical coding model: ingestive and egestive inputs to the feeding central pattern generator (CPG) release different modulators, which act via different second messengers to prime motor activity in different ways. The ingestive input to the CPG (neuron CBI-2) releases the peptides feeding circuit activating peptide and cerebral peptide 2, which produce an ingestive pattern of activity. The egestive input to the CPG (the esophageal nerve) releases the peptide small cardioactive peptide. This model is based on research that focused on a single aspect of motor control (radula opening). Here we ask whether repetition priming is observed if activity is triggered with a neuron within the core CPG itself and demonstrate that it is not. Moreover, previous studies demonstrated that effects of modulatory neurotransmitters that induce repetition priming persist. This suggests that it should be possible to "prime" motor programs triggered from within the CPG by first stimulating extrinsic modulatory inputs. We demonstrate that programs triggered after ingestive input activation are ingestive and programs triggered after egestive input activation are egestive. We ask where this priming occurs and demonstrate modifications within the CPG itself. This arrangement is likely to have important consequences for "task" switching, i.e., the cessation of one type of motor activity and the initiation of another. Copyright © 2016 the American Physiological Society.

  6. Differences and the relationship in default mode network intrinsic activity and functional connectivity in mild Alzheimer's disease and amnestic mild cognitive impairment.

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    Weiler, Marina; Teixeira, Camila Vieira Ligo; Nogueira, Mateus Henrique; de Campos, Brunno Machado; Damasceno, Benito Pereira; Cendes, Fernando; Balthazar, Marcio Luiz Figueredo

    2014-10-01

    There is evidence that the default mode network (DMN) functional connectivity is impaired in Alzheimer's disease (AD) and few studies also reported a decrease in DMN intrinsic activity, measured by the amplitude of low-frequency fluctuations (ALFFs). In this study, we analyzed the relationship between DMN intrinsic activity and functional connectivity, as well as their possible implications on cognition in patients with mild AD and amnestic mild cognitive impairment (aMCI) and healthy controls. In addition, we evaluated the differences both in connectivity and ALFF values between these groups. We recruited 29 controls, 20 aMCI, and 32 mild AD patients. To identify the DMN, functional connectivity was calculated by placing a seed in the posterior cingulate cortex (PCC). Within the DMN mask obtained, we calculated regional average ALFFs. Compared with controls, aMCI patients showed decreased ALFFs in the temporal region; compared with AD, aMCI showed higher values in the PCC but lower in the temporal area. The mild AD group had lower ALFFs in the PCC compared with controls. There was no difference between the connectivity in the aMCI group compared with the other groups, but AD patients showed decreased connectivity in the frontal, parietal, and PCC. Also, PCC ALFFs correlated to functional connectivity in nearly all subregions. Cognitive tests correlated to connectivity values but not to ALFFs. In conclusion, we found that DMN connectivity and ALFFs are correlated in these groups. Decreased PCC ALFFs disrupt the DMN functional organization, leading to cognitive problems in the AD spectrum.

  7. Intrinsic brain activity in altered states of consciousness: how conscious is the default mode of brain function?

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    Boly, M; Phillips, C; Tshibanda, L; Vanhaudenhuyse, A; Schabus, M; Dang-Vu, T T; Moonen, G; Hustinx, R; Maquet, P; Laureys, S

    2008-01-01

    Spontaneous brain activity has recently received increasing interest in the neuroimaging community. However, the value of resting-state studies to a better understanding of brain-behavior relationships has been challenged. That altered states of consciousness are a privileged way to study the relationships between spontaneous brain activity and behavior is proposed, and common resting-state brain activity features observed in various states of altered consciousness are reviewed. Early positron emission tomography studies showed that states of extremely low or high brain activity are often associated with unconsciousness. However, this relationship is not absolute, and the precise link between global brain metabolism and awareness remains yet difficult to assert. In contrast, voxel-based analyses identified a systematic impairment of associative frontoparieto-cingulate areas in altered states of consciousness, such as sleep, anesthesia, coma, vegetative state, epileptic loss of consciousness, and somnambulism. In parallel, recent functional magnetic resonance imaging studies have identified structured patterns of slow neuronal oscillations in the resting human brain. Similar coherent blood oxygen level-dependent (BOLD) systemwide patterns can also be found, in particular in the default-mode network, in several states of unconsciousness, such as coma, anesthesia, and slow-wave sleep. The latter results suggest that slow coherent spontaneous BOLD fluctuations cannot be exclusively a reflection of conscious mental activity, but may reflect default brain connectivity shaping brain areas of most likely interactions in a way that transcends levels of consciousness, and whose functional significance remains largely in the dark.

  8. Galectin-3 silencing inhibits epirubicin-induced ATP binding cassette transporters and activates the mitochondrial apoptosis pathway via β-catenin/GSK-3β modulation in colorectal carcinoma.

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    Yung-Kuo Lee

    Full Text Available Multidrug resistance (MDR, an unfavorable factor compromising the treatment efficacy of anticancer drugs, involves the upregulation of ATP binding cassette (ABC transporters and induction of galectin-3 signaling. Galectin-3 plays an anti-apoptotic role in many cancer cells and regulates various pathways to activate MDR. Thus, the inhibition of galectin-3 has the potential to enhance the efficacy of the anticancer drug epirubicin. In this study, we examined the effects and mechanisms of silencing galectin-3 via RNA interference (RNAi on the β-catenin/GSK-3β pathway in human colon adenocarcinoma Caco-2 cells. Galectin-3 knockdown increased the intracellular accumulation of epirubicin in Caco-2 cells; suppressed the mRNA expression of galectin-3, β-catenin, cyclin D1, c-myc, P-glycoprotein (P-gp, MDR-associated protein (MRP 1, and MRP2; and downregulated the protein expression of P-gp, cyclin D1, galectin-3, β-catenin, c-Myc, and Bcl-2. Moreover, galectin-3 RNAi treatment significantly increased the mRNA level of GSK-3β, Bax, caspase-3, and caspase-9; remarkably increased the Bax-to-Bcl-2 ratio; and upregulated the GSK-3β and Bax protein expressions. Apoptosis was induced by galectin-3 RNAi and/or epirubicin as demonstrated by chromatin condensation, a higher sub-G1 phase proportion, and increased caspase-3 and caspase-9 activity, indicating an intrinsic/mitochondrial apoptosis pathway. Epirubicin-mediated resistance was effectively inhibited via galectin-3 RNAi treatment. However, these phenomena could be rescued after galectin-3 overexpression. We show for the first time that the silencing of galectin-3 sensitizes MDR cells to epirubicin by inhibiting ABC transporters and activating the mitochondrial pathway of apoptosis through modulation of the β-catenin/GSK-3β pathway in human colon cancer cells.

  9. Quercetin, a Natural Flavonoid Interacts with DNA, Arrests Cell Cycle and Causes Tumor Regression by Activating Mitochondrial Pathway of Apoptosis

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    Srivastava, Shikha; Somasagara, Ranganatha R.; Hegde, Mahesh; Nishana, Mayilaadumveettil; Tadi, Satish Kumar; Srivastava, Mrinal; Choudhary, Bibha; Raghavan, Sathees C.

    2016-01-01

    Naturally occurring compounds are considered as attractive candidates for cancer treatment and prevention. Quercetin and ellagic acid are naturally occurring flavonoids abundantly seen in several fruits and vegetables. In the present study, we evaluate and compare antitumor efficacies of quercetin and ellagic acid in animal models and cancer cell lines in a comprehensive manner. We found that quercetin induced cytotoxicity in leukemic cells in a dose-dependent manner, while ellagic acid showed only limited toxicity. Besides leukemic cells, quercetin also induced cytotoxicity in breast cancer cells, however, its effect on normal cells was limited or none. Further, quercetin caused S phase arrest during cell cycle progression in tested cancer cells. Quercetin induced tumor regression in mice at a concentration 3-fold lower than ellagic acid. Importantly, administration of quercetin lead to ~5 fold increase in the life span in tumor bearing mice compared to that of untreated controls. Further, we found that quercetin interacts with DNA directly, and could be one of the mechanisms for inducing apoptosis in both, cancer cell lines and tumor tissues by activating the intrinsic pathway. Thus, our data suggests that quercetin can be further explored for its potential to be used in cancer therapeutics and combination therapy. PMID:27068577

  10. Cryptosporidium parvum has an active hypusine biosynthesis pathway.

    Science.gov (United States)

    Mittal, Nimisha; Morada, Marie; Tripathi, Pankaj; Gowri, V S; Mandal, Swati; Quirch, Alison; Park, Myung Hee; Yarlett, Nigel; Madhubala, Rentala

    2014-06-01

    The protozoan parasite Cryptosporidium parvum causes severe enteric infection and diarrheal disease with substantial morbidity and mortality in untreated AIDS patients and children in developing or resource-limited countries. No fully effective treatment is available. Hypusination of eIF5A is an important post-translational modification essential for cell proliferation. This modification occurs in a two step process catalyzed by deoxyhypusine synthase (DHS) followed by deoxyhypusine hydroxylase. An ORF of 1086bp was identified in the C. parvum (Cp) genome which encodes for a putative polypeptide of 362 amino acids. The recombinant CpDHS protein was purified to homogeneity and used to probe the enzyme's mechanism, structure, and inhibition profile in a series of kinetic experiments. Sequence analysis and structural modeling of CpDHS were performed to probe differences with respect to the DHS of other species. Unlike Leishmania, Trypanosomes and Entamoeba, Cryptosporidium contains only a single gene for DHS. Phylogenetic analysis shows that CpDHS is more closely related to apicomplexan DHS than kinetoplastid DHS. Important residues that are essential for the functioning of the enzyme including NAD(+) binding residues, spermidine binding residues and the active site lysine are conserved between CpDHS and human DHS. N(1)-guanyl-1,7-diaminoheptane (GC7), a potent inhibitor of DHS caused an effective inhibition of infection and growth of C. parvum in HCT-8 cells. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Water channel activities of Mimosa pudica plasma membrane intrinsic proteins are regulated by direct interaction and phosphorylation.

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    Temmei, Yusuke; Uchida, Shinichi; Hoshino, Daisuke; Kanzawa, Nobuyuki; Kuwahara, Michio; Sasaki, Sei; Tsuchiya, Takahide

    2005-08-15

    cDNAs encoding aquaporins PIP1;1, PIP2;1, and TIP1;1 were isolated from Mimosa pudica (Mp) cDNA library. MpPIP1;1 exhibited no water channel activity; however, it facilitated the water channel activity of MpPIP2;1 in a phosphorylation-dependent manner. Mutagenesis analysis revealed that Ser-131 of MpPIP1;1 was phosphorylated by PKA and that cooperative regulation of the water channel activity of MpPIP2;1 was regulated by phosphorylation of Ser-131 of MpPIP1;1. Immunoprecipitation analysis revealed that MpPIP1;1 binds directly to MpPIP2;1 in a phosphorylation-independent manner, suggesting that phosphorylation of Ser-131 of MpPIP1;1 is involved in regulation of the structure of the channel complex with MpMIP2;1 and thereby affects water channel activity.

  12. Epigenetic regulator Lid maintains germline stem cells through regulating JAK-STAT signaling pathway activity

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    Lama Tarayrah

    2015-11-01

    Full Text Available Signaling pathways and epigenetic mechanisms have both been shown to play essential roles in regulating stem cell activity. While the role of either mechanism in this regulation is well established in multiple stem cell lineages, how the two mechanisms interact to regulate stem cell activity is not as well understood. Here we report that in the Drosophila testis, an H3K4me3-specific histone demethylase encoded by little imaginal discs (lid maintains germline stem cell (GSC mitotic index and prevents GSC premature differentiation. Lid is required in germ cells for proper expression of the Stat92E transcription factor, the downstream effector of the Janus kinase signal transducer and activator of transcription (JAK-STAT signaling pathway. Our findings support a germ cell autonomous role for the JAK-STAT pathway in maintaining GSCs and place Lid as an upstream regulator of this pathway. Our study provides new insights into the biological functions of a histone demethylase in vivo and sheds light on the interaction between epigenetic mechanisms and signaling pathways in regulating stem cell activities.

  13. Effects of four short-chain fatty acids or salts on the dynamics of nitrogen transformations and intrinsic protease activity of alfalfa silage.

    Science.gov (United States)

    Yuan, XianJun; Wen, AiYou; Desta, Seare T; Dong, ZhiHao; Shao, Tao

    2017-07-01

    Short-chain fatty salts have been widely used as food and forage preservatives because of their antimicrobial properties. This study evaluated the effects of four chemical compounds with antimicrobial properties on nitrogen transformations and intrinsic protease activity of alfalfa silage. Potassium diformate (PD) and formic acid (FA) rapidly reduced silage pH. Silages treated with sodium diacetate (SD) and calcium propionate (CAP) had higher final peptide N concentrations than other silage. The free amino acid N contents in PD and FA treated silages were lower than other silages at all intervals of ensilage. The ammonia N concentrations in FA and PD silages were the lowest, followed by SD and CAP silages. As ensiling progressed, the aminopeptidase activity was completely lost by day 5 for FA and PD silages and inactive by day 7 for SD silage, while it remained active after day 7 for control and CAP silage. The carboxypeptidase activities in FA and PD silages were already reduced below 50% by day 1 of ensiling. Potassium diformate was as effective as formic acid in depressing the proteolysis, while sodium diacetate and calcium propionate were inferior to formic acid in protecting alfalfa proteins from being hydrolysed. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  14. The role of hyperpolarization-activated cationic current in spike-time precision and intrinsic resonance in cortical neurons in vitro.

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    Gastrein, Philippe; Campanac, Emilie; Gasselin, Célia; Cudmore, Robert H; Bialowas, Andrzej; Carlier, Edmond; Fronzaroli-Molinieres, Laure; Ankri, Norbert; Debanne, Dominique

    2011-08-01

    Hyperpolarization-activated cyclic nucleotide modulated current (I(h)) sets resonance frequency within the θ-range (5–12 Hz) in pyramidal neurons. However, its precise contribution to the temporal fidelity of spike generation in response to stimulation of excitatory or inhibitory synapses remains unclear. In conditions where pharmacological blockade of I(h) does not affect synaptic transmission, we show that postsynaptic h-channels improve spike time precision in CA1 pyramidal neurons through two main mechanisms. I(h) enhances precision of excitatory postsynaptic potential (EPSP)--spike coupling because I(h) reduces peak EPSP duration. I(h) improves the precision of rebound spiking following inhibitory postsynaptic potentials (IPSPs) in CA1 pyramidal neurons and sets pacemaker activity in stratum oriens interneurons because I(h) accelerates the decay of both IPSPs and after-hyperpolarizing potentials (AHPs). The contribution of h-channels to intrinsic resonance and EPSP waveform was comparatively much smaller in CA3 pyramidal neurons. Our results indicate that the elementary mechanisms by which postsynaptic h-channels control fidelity of spike timing at the scale of individual neurons may account for the decreased theta-activity observed in hippocampal and neocortical networks when h-channel activity is pharmacologically reduced.

  15. Editing of misaligned 3'-termini by an intrinsic 3'-5' exonuclease activity residing in the PHP domain of a family X DNA polymerase.

    Science.gov (United States)

    Baños, Benito; Lázaro, José M; Villar, Laurentino; Salas, Margarita; de Vega, Miguel

    2008-10-01

    Bacillus subtilis gene yshC encodes a family X DNA polymerase (PolX(Bs)), whose biochemical features suggest that it plays a role during DNA repair processes. Here, we show that, in addition to the polymerization activity, PolX(Bs) possesses an intrinsic 3'-5' exonuclease activity specialized in resecting unannealed 3'-termini in a gapped DNA substrate. Biochemical analysis of a PolX(Bs) deletion mutant lacking the C-terminal polymerase histidinol phosphatase (PHP) domain, present in most of the bacterial/archaeal PolXs, as well as of this separately expressed protein region, allow us to state that the 3'-5' exonuclease activity of PolX(Bs) resides in its PHP domain. Furthermore, site-directed mutagenesis of PolX(Bs) His339 and His341 residues, evolutionary conserved in the PHP superfamily members, demonstrated that the predicted metal binding site is directly involved in catalysis of the exonucleolytic reaction. The implications of the unannealed 3'-termini resection by the 3'-5' exonuclease activity of PolX(Bs) in the DNA repair context are discussed.

  16. B cell antigen receptor-induced activation of an IRAK4-dependent signaling pathway revealed by a MALT1-IRAK4 double knockout mouse model

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    Dufner Almut

    2011-03-01

    Full Text Available Abstract Background The B cell antigen receptor (BCR and pathogen recognition receptors, such as Toll-like receptor 4 (TLR4, act in concert to control adaptive B cell responses. However, little is known about the signaling pathways that integrate BCR activation with intrinsic TLR4 stimulation. Antigen receptors initialize activation of the inducible transcription factor nuclear factor-κB (NF-κB via recruitment of the membrane-associated guanylate kinase caspase recruitment domain protein 11 (CARD11, the adapter molecule B cell CLL/lymphoma 10 (BCL10, and the "paracaspase" mucosa-associated lymphoid tissue lymphoma translocation gene 1 (MALT1 into lipid rafts. Upon BCR triggering, this activation strictly depends on BCL10, but not on MALT1, leading to the hypothesis that a MALT1-independent NF-κB activation pathway contributes to BCR-induced NF-κB activation downstream of BCL10. The identity of this pathway has remained elusive. Results Using genetic and biochemical approaches, we demonstrate that the IRAK4- and IRAK1-dependent TLR signaling branch is activated upon BCR triggering to induce partial NF-κB activation. BCR-induced MALT1-independent IκB degradation and B cell proliferation were inhibited in MALT1/IRAK4 double knockout B cells. Moreover, IRAK1 was recruited into lipid rafts upon BCR stimulation and activated following transient recruitment of IRAK4. Conclusion We propose that the observed crosstalk between BCR and TLR signaling components may contribute to the discrimination of signals that emanate from single and dual receptor engagement to control adaptive B cell responses.

  17. Monitoring the Activation of the DNA Damage Response Pathway in a 3D Spheroid Model.

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    Mondesert, Odile; Frongia, Céline; Clayton, Olivia; Boizeau, Marie-Laure; Lobjois, Valérie; Ducommun, Bernard

    2015-01-01

    Monitoring the DNA-Damage Response (DDR) activated pathway in multicellular tumor spheroid models is an important challenge as these 3D models have demonstrated their major relevance in pharmacological evaluation. Herein we present DDR-Act-FP, a fluorescent biosensor that allows detection of DDR activation through monitoring of the p21 promoter p53-dependent activation. We show that cells expressing the DDR-Act-FP biosensor efficiently report activation of the DDR pathway after DNA damage and its pharmacological manipulation using ATM kinase inhibitors. We also report the successful use of this assay to screen a small compound library in order to identify activators of the DDR response. Finally, using multicellular spheroids expressing the DDR-Act-FP we demonstrate that DDR activation and its pharmacological manipulation with inhibitory and activatory compounds can be efficiently monitored in live 3D spheroid model. This study paves the way for the development of innovative screening and preclinical evaluation assays.

  18. Impact of MAPK pathway activation in BRAFV600 melanoma on T cell and Dendritic Cell function

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    Patrick Alexander Ott

    2013-10-01

    Full Text Available Constitutive upregulation of the MAPK pathway by a BRAFV600 mutation occurs in about half of melanomas. This leads to increased oncogenic properties such as tumor cell invasion, metastatic potential, and resistance to apoptosis. Blockade of the MAPK pathway with highly specific kinase inhibitors induces unprecedented tumor response rates in patients with advanced BRAFV600 mutant melanoma. Immune checkpoint blockade with monoclonal antibodies targeting CTLA-4 and PD-1/PD-L1 has also demonstrated striking anti-tumor activity in patients with advanced melanoma. Tumor responses are likely limited by multiple additional layers of immune suppression in the tumor microenvironment. There is emerging preclinical and clinical evidence suggesting that MAPK inhibition has a beneficial effect on the immunosuppressive tumor microenvironment, providing a strong rationale for combined immunotherapy and MAPK pathway inhibition in melanoma. The T cell response has been the main focus in the studies reported to date. Since dendritic cells (DCs are important in the induction of tumor-specific T cell responses, the impact of MAPK pathway activation in melanoma on DC function is critical for the melanoma directed immune response. BRAFV600E melanoma cells modulate DC through the MAPK pathway because its blockade in melanoma cells can reverse suppression of DC function. As both MEK/BRAF inhibition and immune checkpoint blockade have recently taken center stage in the treatment of melanoma, a deeper understanding of how MAPK pathway inhibition affects the tumor immune response is needed.

  19. Impact of MAPK Pathway Activation in BRAFV600 Melanoma on T Cell and Dendritic Cell Function

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    Patrick A. Ott

    2013-10-01

    Full Text Available Constitutive upregulation of the MAPK pathway by a BRAFV600 mutation occurs in about half of melanomas. This leads to increased oncogenic properties such as tumor cell invasion, metastatic potential, and resistance to apoptosis. Blockade of the MAPK pathway with highly specific kinase inhibitors induces unprecedented tumor response rates in patients with advanced BRAFV600 mutant melanoma. Immune checkpoint blockade with monoclonal antibodies targeting cytotoxic T-lymphocyte antigen 4 and programed death-1/PD-L1 has also demonstrated striking anti-tumor activity in patients with advanced melanoma. Tumor responses are likely limited by multiple additional layers of immune suppression in the tumor microenvironment. There is emerging preclinical and clinical evidence suggesting that MAPK inhibition has a beneficial effect on the immunosuppressive tumor microenvironment, providing a strong rationale for combined immunotherapy and MAPK pathway inhibition in melanoma. The T cell response has been the main focus in the studies reported to date. Since dendritic cells (DCs are important in the induction of tumor-specific T cell responses, the impact of MAPK pathway activation in melanoma on DC function is critical for the melanoma directed immune response. BRAFV600E melanoma cells modulate DCs through the MAPK pathway because its blockade in melanoma cells can reverse suppression of DC function. As both MEK/BRAF inhibition and immune checkpoint blockade have recently taken center stage in the treatment of melanoma, a deeper understanding of how MAPK pathway inhibition affects the tumor immune response is needed.

  20. Alkaloids from Piper nigrum Exhibit Antiinflammatory Activity via Activating the Nrf2/HO-1 Pathway.

    Science.gov (United States)

    Ngo, Quynh Mai Thi; Tran, Phuong Thao; Tran, Manh Hung; Kim, Jeong Ah; Rho, Seong Soo; Lim, Chi-Hwan; Kim, Jin-Cheol; Woo, Mi Hee; Choi, Jae Sui; Lee, Jeong-Hyung; Min, Byung Sun

    2017-04-01

    In the present study, ten alkaloids, namely chabamide (1), pellitorine (2), retrofractamide A (3), pyrroperine (4), isopiperolein B (5), piperamide C9:1 (8E) (6), 6,7-dehydrobrachyamide B (7), 4,5-dihydropiperine (8), dehydropipernonaline (9), and piperine (10), were isolated from the fruits of Piper nigrum. Among these, chabamide (1), pellitorine (2), retrofractamide A (3), isopiperolein B (5), and 6,7-dehydrobrachyamide B (7) exhibited significant inhibitory activity on lipopolysaccharide-induced nitric oxide (NO) production in RAW264.7 cells, with IC50 values of 6.8, 14.5, 30.2, 23.7, and 38.5 μM, respectively. Furthermore, compound 1 inhibited lipopolysaccharide-induced NO production in bone marrow-derived macrophages with IC50 value of 9.5 μM. Consistent with NO inhibition, treatment of RAW264.7 cells with chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) suppressed expression of inducible NO synthase and cyclooxygenase-2. Chabamide (1), pellitorine (2), and 6,7-dehydrobrachyamide B (7) induced heme-oxygenase-1 expression at the transcriptional level. In addition, compound 1 induced the nuclear translocation of nuclear factor-E2-related factor 2 (Nrf2) and upregulated the expression of Nrf2 target genes, NAD(P)H:quinone oxidoreductase 1 and γ-glutamyl cysteine synthetase catalytic subunit, in a concentration-dependent manner in RAW264.7 cells. These findings suggest that chabamide (1) from P. nigrum exert antiinflammatory effects via the activation of the Nrf2/heme-oxygenase-1 pathway; hence, it might be a promising candidate for the treatment of inflammatory diseases. Copyright © 2017 John Wiley & Sons, Ltd.

  1. In vivo imaging of Hedgehog pathway activation with a nuclear fluorescent reporter.

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    John K Mich

    Full Text Available The Hedgehog (Hh pathway is essential for embryonic development and tissue regeneration, and its dysregulation can lead to birth defects and tumorigenesis. Understanding how this signaling mechanism contributes to these processes would benefit from an ability to visualize Hedgehog pathway activity in live organisms, in real time, and with single-cell resolution. We report here the generation of transgenic zebrafish lines that express nuclear-localized mCherry fluorescent protein in a Gli transcription factor-dependent manner. As demonstrated by chemical and genetic perturbations, these lines faithfully report Hedgehog pathway state in individual cells and with high detection sensitivity. They will be valuable tools for studying dynamic Gli-dependent processes in vertebrates and for identifying new chemical and genetic regulators of the Hh pathway.

  2. Concentrated bovine milk whey active proteins facilitate osteogenesis through activation of the JNK-ATF4 pathway.

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    Tsuji-Naito, Kentaro; Jack, Ralph W

    2012-01-01

    Concentrated fractions of low molecular weight whey proteins (1-30 kDa), that is concentrated bovine milk whey active proteins (CBP), have been found to enhance bone formation in both in vivo and clinical studies, but the underlying mechanisms are poorly understood. In this study, we found that CBP promoted osteoblastic differentiation in normal human osteoblasts, and determined the involvement of the c-jun NH2-terminal kinase (JNK)-activating transcription factor 4 (ATF4) pathway. We observed that alkaline phosphatase activity and mineralization were significantly induced by CBP treatment. In addition, mRNA expression of ATF4 was intensely elevated in CBP-treated osteoblasts, indicating that the late-phase events of differentiation were promoted. We found that CBP activated the phosphorylation of JNK and extracellular signal-regulated kinase (ERK). Furthermore, pathway analyses using the various signaling pathway-specific inhibitors revealed that JNK activation, but not ERK activation, is essential for CBP-induced mineralization and ATF4 expression. Our results indicate that the JNK-mediated ATF4 pathway is required for CBP-promotive osteogenesis.

  3. Protein-Metal Organic Framework Hybrid Composites with Intrinsic Peroxidase-like Activity as a Colorimetric Biosensing Platform.

    Science.gov (United States)

    Yin, Yuqing; Gao, Chen Ling; Xiao, Qi; Lin, Guo; Lin, Zian; Cai, Zongwei; Yang, Huang-Hao

    2016-10-04

    Artificial enzyme mimetics have received considerable attention because natural enzymes have some significant drawbacks, including enzyme autolysis, low catalytic activity, poor recovery and low stability to environmental changes. Herein, we demonstrated a facile approach for one-pot synthesis of hemeprotein-metal organic framework hybrid composites (H-MOFs) by using bovine hemoglobin (BHb) and zeolitic imidazolate framework-8 (ZIF-8) as a model reaction system. Surprisingly, the new hybrid composites exhibits 423% increase in peroxidase-like catalytic activity compared to free BHb. Taking advantages of the unique pore structure of H-MOFs with high catalytic property, a H-MOFs-based colorimetric biosensing platform was newly constructed and applied for the fast and sensitive detection of hydrogen peroxide (H2O2) and phenol. The corresponding detection limits as low as 1.0 μM for each analyte with wide linear ranges (0-800 μM for H2O2 and 0-200 μM for phenol) were obtained by naked-eye visualization. Significantly, sensitive and selective method for visual assay of trace H2O2 in cell and phenol in sewage was achieved with this platform. The stability of H-MOFs was also examined and excellent reproducibility and recyclability without losing in its activity were observed. In addition, the general applicability of H-MOFs was also investigated by using other hemeproteins (horseradish peroxidase, and myoglobin) and the corresponding catalytic activities were 291% and 273% enhancement, respectively. This present work not only expands the application of MOFs, but also provides an alternative technique for biological and environmental sample assay.

  4. Transsulfuration is an active pathway for cysteine biosynthesis in Trypanosoma rangeli.

    Science.gov (United States)

    Romero, Ibeth; Téllez, Jair; Yamanaka, Lais Eiko; Steindel, Mario; Romanha, Alvaro José; Grisard, Edmundo Carlos

    2014-04-24

    Cysteine, a sulfur-containing amino acid, plays an important role in a variety of cellular functions such as protein biosynthesis, methylation, and polyamine and glutathione syntheses. In trypanosomatids, glutathione is conjugated with spermidine to form the specific antioxidant thiol trypanothione (T[SH]2) that plays a central role in maintaining intracellular redox homeostasis and providing defence against oxidative stress. We cloned and characterised genes coding for a cystathionine β-synthase (CβS) and cysteine synthase (CS), key enzymes of the transsulfuration and assimilatory pathways, respectively, from the hemoflagellate protozoan parasite Trypanosoma rangeli. Our results show that T. rangeli CβS (TrCβS), similar to its homologs in T. cruzi, contains the catalytic domain essential for enzymatic activity. Unlike the enzymes in bacteria, plants, and other parasites, T. rangeli CS lacks two of the four lysine residues (Lys26 and Lys184) required for activity. Enzymatic studies using T. rangeli extracts confirmed the absence of CS activity but confirmed the expression of an active CβS. Moreover, CβS biochemical assays revealed that the T. rangeli CβS enzyme also has serine sulfhydrylase activity. These findings demonstrate that the RTS pathway is active in T. rangeli, suggesting that this may be the only pathway for cysteine biosynthesis in this parasite. In this sense, the RTS pathway appears to have an important functional role during the insect stage of the life cycle of this protozoan parasite.

  5. Pheromone-induced morphogenesis improves osmoadaptation capacity by activating the HOG MAPK pathway.

    Science.gov (United States)

    Baltanás, Rodrigo; Bush, Alan; Couto, Alicia; Durrieu, Lucía; Hohmann, Stefan; Colman-Lerner, Alejandro

    2013-04-23

    Environmental and internal conditions expose cells to a multiplicity of stimuli whose consequences are difficult to predict. We investigate the response to mating pheromone of yeast cells adapted to high osmolarity. Events downstream of pheromone binding involve two mitogen-activated protein kinase (MAPK) cascades: the pheromone response (PR) and the cell wall integrity (CWI) response. Although the PR MAPK pathway shares components with a third MAPK pathway, the high osmolarity (HOG) response, each one is normally only activated by its cognate stimulus, a phenomenon called insulation. We found that in cells adapted to high osmolarity, PR activated the HOG pathway in a pheromone- and osmolarity-dependent manner. Activation of HOG by the PR was not due to loss of insulation, but rather a response to a reduction in internal osmolarity, which resulted from an increase in glycerol release caused by the PR. By analyzing single-cell time courses, we found that stimulation of HOG occurred in discrete bursts that coincided with the "shmooing" morphogenetic process. Activation required the polarisome, the CWI MAPK Slt2, and the aquaglyceroporin Fps1. HOG activation resulted in high glycerol turnover, which improved adaptability to rapid changes in osmolarity. Our work shows how a differentiation signal can recruit a second, unrelated sensory pathway to fine-tune yeast response in a complex environment.

  6. Activation of a mitogen-activated protein kinase pathway in Arabidopsis by chitin.

    Science.gov (United States)

    Wan, Jinrong; Zhang, Shuqun; Stacey, Gary

    2004-03-01

    SUMMARY Chitin, a polysaccharide composed of beta-1-->4-linked N-acetyl-d-glucosamine, has been shown or implicated as a signal in plant defence and development. However, the key components of chitin perception and downstream signalling in non-leguminous plants are largely unknown. In recent years, mitogen-activated protein kinases (MAPKs) and their cascades were shown to transduce various extracellular stimuli into internal cellular responses. To investigate the possible involvement of MAPKs in chitin signalling in plants, the model plant Arabidopsis thaliana was treated with crab-shell chitin and also with the purified chitin oligomers (degree of polymerization, d.p. = 2-8). Both mRNA levels and kinase activity of two MAPK genes, AtMPK6 and AtMPK3, were monitored after treatment. The mRNA of AtMPK3 was strongly up-regulated by both chitin and its larger oligomers (d.p. = 6-8), but the mRNA of AtMPK6 did not appear to be regulated by these treatments. However, the kinase activity of both MAPKs was induced by chitin and the larger oligomers (d.p. = 6-8), with AtMPK6 much more strongly induced. In addition, WRKY22, WRKY29, WRKY33 and WRKY53, which encode four WRKY transcription factors that recognize TTGAC(C/T) W-box elements in promoters of numerous plant defence-related genes, were up-regulated by these treatments. WRKY33 and WRKY53 expression was induced by the transgenic expression of the tobacco MAPKK NtMEK2 active mutant NtMEK2(DD), suggesting a potential role for these WRKY transcription factors in relaying the signal generated from the MAPK cascade to downstream genes. These data suggest that AtMPK6/AtMPK3 and WRKY transcription factors (such as WRKY33 and WRKY53) may be important components of a pathway involved in chitin signalling in Arabidopsis plants.

  7. In vitro Neurons in Mammalian Cortical Layer 4 Exhibit Intrinsic Oscillatory Activity in the 10- to 50-Hz Frequency Range

    Science.gov (United States)

    Llinas, Rodolfo R.; Grace, Anthony A.; Yarom, Yosef

    1991-02-01

    We report here the presence of fast subthreshold oscillatory potentials recorded in vitro from neurons within layer 4 of the guinea pig frontal cortex. Two types of oscillatory neurons were recorded: (i) One type exhibited subthreshold oscillations whose frequency increased with membrane depolarization and encompassed a range of 10-45 Hz. Action potentials in this type of neuron demonstrated clear after-hyperpolarizations. (ii) The second type of neuron was characterized by narrow-frequency oscillations near 35-50 Hz. These oscillations often outlasted the initiating depolarizing stimulus. No calcium component could be identified in their action potential. In both types of cell the subthreshold oscillations were tetrodotoxin-sensitive, indicating that the depolarizing phase of the oscillation was generated by a voltage-dependent sodium conductance. The initial depolarizing phase was followed by a potassium conductance responsible for the falling phase of the oscillatory wave. In both types of cell, the subthreshold oscillation could trigger spikes at the oscillatory frequency, if the membrane was sufficiently depolarized. Combining intracellular recordings with Lucifer yellow staining showed that the narrow-frequency oscillatory activity was produced by a sparsely spinous interneuron located in layer 4 of the cortex. This neuron has extensive local axonal collaterals that ramify in layers 3 and 4 such that they may contribute to the columnar synchronization of activity in the 40- to 50-Hz range. Cortical activity in this frequency range has been proposed as the basis for the "conjunctive properties" of central nervous system networks.

  8. Retinoblastoma pathway defects show differential ability to activate the constitutive DNA damage response in human tumorigenesis

    DEFF Research Database (Denmark)

    Tort, F.; Bartkova, J.; Sehested, M.

    2006-01-01

    activation. Here, we show that, in a series of human colorectal adenomas, those with deregulation of cyclin D1 and/or p16(Ink4a) showed little evidence of constitutive DNA damage response (DDR), contrary to cyclin E-overexpressing higher-grade cases. These observations were consistent with diverse cell...... culture models with differential defects of retinoblastoma pathway components, as overexpression of cyclin D1 or lack of p16(Ink4a), either alone or combined, did not elicit detectable DDR. In contrast, inactivation of pRb, the key component of the pathway, activated the DDR in cultured human or mouse...

  9. Quantifying signaling pathway activation to monitor the quality of induced pluripotent stem cells.

    Science.gov (United States)

    Makarev, Eugene; Fortney, Kristen; Litovchenko, Maria; Braunewell, Karl H; Zhavoronkov, Alex; Atala, Anthony

    2015-09-15

    Many attempts have been made to evaluate the safety and potency of human induced pluripotent stem cells (iPSCs) for clinical applications using transcriptome data, but results so far have been ambiguous or even contradictory. Here, we characterized stem cells at the pathway level, rather than at the gene level as has been the focus of previous work. We meta-analyzed publically-available gene expression data sets and evaluated signaling and metabolic pathway activation profiles for 20 human embryonic stem cell (ESC) lines, 12 human iPSC lines, five embryonic body lines, and six fibroblast cell lines. We demonstrated the close resemblance of iPSCs with ESCs at the pathway level, and provided examples of how pathway activity can be applied to identify iPSC line abnormalities or to predict in vitro differentiation potential. Our results indicate that pathway activation profiling is a promising strategy for evaluating the safety and potency of iPSC lines in translational medicine applications.

  10. Sorbic acid stress activates the Candida glabrata high osmolarity glycerol MAP kinase pathway

    Science.gov (United States)

    Jandric, Zeljkica; Gregori, Christa; Klopf, Eva; Radolf, Martin; Schüller, Christoph

    2013-01-01

    Weak organic acids such as sorbic acid are important food preservatives and powerful fungistatic agents. These compounds accumulate in the cytosol and disturb the cellular pH and energy homeostasis. Candida glabrata is in many aspects similar to Saccharomyces cerevisiae. However, with regard to confrontation to sorbic acid, two of the principal response pathways behave differently in C. glabrata. In yeast, sorbic acid stress causes activation of many genes via the transcription factors Msn2 and Msn4. The C. glabrata homologs CgMsn2 and CgMsn4 are apparently not activated by sorbic acid. In contrast, in C. glabrata the high osmolarity glycerol (HOG) pathway is activated by sorbic acid. Here we show that the MAP kinase of the HOG pathway, CgHog1, becomes phosphorylated and has a function for weak acid stress resistance. Transcript profiling of weak acid treated C. glabrata cells suggests a broad and very similar response pattern of cells lacking CgHog1 compared to wild type which is over lapping with but distinct from S. cerevisiae. The PDR12 gene was the highest induced gene in both species and it required CgHog1 for full expression. Our results support flexibility of the response cues for general stress signaling pathways, even between closely related yeasts, and functional extension of a specific response pathway. PMID:24324463

  11. Sorbic acid stress activates the Candida glabrata high osmolarity glycerol MAP kinase pathway

    Directory of Open Access Journals (Sweden)

    Zeljkica eJandric

    2013-11-01

    Full Text Available Weak organic acids such as sorbic acid are important food preservatives and powerful fungistatic agents. These compounds accumulate in the cytosol and disturb the cellular pH and energy homeostasis. Candida glabrata is in many aspects similar to Saccharomyces cerevisiae. However, with regard to confrontation to sorbic acid, two of the principal response pathways behave differently in Candida glabrata. In yeast, sorbic acid stress causes activation of many genes via the transcription factors Msn2 and Msn4. The C. glabrata homologues CgMsn2 and CgMsn4 are apparently not activated by sorbic acid. In contrast, in C. glabrata the high osmolarity glycerol (HOG pathway is activated by sorbic acid. Here we show that the MAP kinase of the HOG pathway, CgHog1, becomes phosphorylated and has a function for weak acid stress resistance. Transcript profiling of weak acid treated C. glabrata cells suggests a broad and very similar response pattern of cells lacking CgHog1 compared to wild type which is over lapping with but distinct from S. cerevisiae. The PDR12 gene was the highest induced gene in both species, and required CgHog1 for full expression. Our results support flexibility of the response cues for general stress signaling pathways, even between closely related yeasts, and functional extension of a specific response pathway.

  12. Selenium Deficiency Attenuates Chicken Duodenal Mucosal Immunity via Activation of the NF-κb Signaling Pathway.

    Science.gov (United States)

    Liu, Zhe; Qu, Yanpeng; Wang, Jianfa; Wu, Rui

    2016-08-01

    Selenium (Se) deficiency can cause intestinal mucosal inflammation, which is related to activation of nuclear transcription factor kappa-B (NF-κB) signaling pathway. However, the mechanism of inflammatory response in chicken duodenal mucosa caused by Se deficiency and its relationship with the NF-κB signaling pathway remain elusive. In this study, we firstly obtained Se-deficient chickens bred with 0.01 mg/kg Se and the normal chickens bred with 0.4 mg/kg Se for 35 days. Then, NF-κB signaling pathway, secretory immunoglobulin A (SIgA), inflammatory cytokines, oxidized glutathione, glutathione peroxidase, and glutathione activities were determined. The results showed that Se deficiency obviously enhanced p50, p65, and p65 DNA-binding activities. The phosphorylation of IκB-α and phosphorylation of kappa-B kinase subunit alpha (IKKα) and IKKα were elevated, but IκB-α was decreased (P mucosal immunity via activation of NF-κB signaling pathway regulated by redox activity, which suggested that Se is a crucial host factor involved in regulating inflammation.

  13. Activation of JNK/Bim/Bax pathway in UV-induced apoptosis

    Science.gov (United States)

    Liu, Lei; Hui, Li; Zhang, Zhen-zhen

    2011-03-01

    Cell apoptosis induced by UV irradiation is a highly complex process in which different molecular signaling pathways are involved. JNK has been proposed as an important regulator in UV irradiation-induced apoptosis. However, the molecular mechanism through which JNK regulates apoptosis, especially how JNK activates Bax in response to UV irradiation is still controversial. In this study, using real-time single-cell analysis, we studied the machinery of Bax activation during UV-induced apoptosis. UV treatment resulted in a series of events: phosphorylation of JNK, mitochondrial translocation of Bim, and subsequent activation of Bax. The activation of Bim and Bax could be inhibited in the presence of SP600125 (a specific inhibitor of JNK), suggesting that UV irradiation activated the JNK/Bim/Bax pathway.

  14. EGF stimulates the activation of EGF receptors and the selective activation of major signaling pathways during mitosis.

    Science.gov (United States)

    Wee, Ping; Shi, Huaiping; Jiang, Jennifer; Wang, Yuluan; Wang, Zhixiang

    2015-03-01

    Mitosis and epidermal growth factor (EGF) receptor (EGFR) are both targets for cancer therapy. The role of EGFR signaling in mitosis has been rarely studied and poorly understood. The limited studies indicate that the activation of EGFR and downstream signaling pathways is mostly inhibited during mitosis. However, we recently showed that EGFR is phosphorylated in response to EGF stimulation in mitosis. Here we studied EGF-induced EGFR activation and the activation of major signaling pathways downstream of EGFR during mitosis. We showed that EGFR was strongly activated by EGF during mitosis as all the five major tyrosine residues including Y992, Y1045, Y1068, Y1086, and Y1173 were phosphorylated to a level similar to that in the interphase. We further showed that the activated EGFR is able to selectively activate some downstream signaling pathways while avoiding others. Activated EGFR is able to activate PI3K and AKT2, but not AKT1, which may be responsible for the observed effects of EGF against nocodazole-induced cell death. Activated EGFR is also able to activate c-Src, c-Cbl and PLC-γ1 during mitosis. However, activated EGFR is unable to activate ERK1/2 and their downstream substrates RSK and Elk-1. While it activated Ras, EGFR failed to fully activate Raf-1 in mitosis due to the lack of phosphorylation at Y341 and the lack of dephosphorylation at pS259. We conclude that contrary to the dogma, EGFR is activated by EGF during mitosis. Moreover, EGFR-mediated cell signaling is regulated differently from the interphase to specifically serve the needs of the cell in mitosis.

  15. Activation of the yeast Hippo pathway by phosphorylation-dependent assembly of signaling complexes.

    Science.gov (United States)

    Rock, Jeremy M; Lim, Daniel; Stach, Lasse; Ogrodowicz, Roksana W; Keck, Jamie M; Jones, Michele H; Wong, Catherine C L; Yates, John R; Winey, Mark; Smerdon, Stephen J; Yaffe, Michael B; Amon, Angelika

    2013-05-17

    Scaffold-assisted signaling cascades guide cellular decision-making. In budding yeast, one such signal transduction pathway called the mitotic exit network (MEN) governs the transition from mitosis to the G1 phase of the cell cycle. The MEN is conserved and in metazoans is known as the Hippo tumor-suppressor pathway. We found that signaling through the MEN kinase cascade was mediated by an unusual two-step process. The MEN kinase Cdc15 first phosphorylated the scaffold Nud1. This created a phospho-docking site on Nud1, to which the effector kinase complex Dbf2-Mob1 bound through a phosphoserine-threonine binding domain, in order to be activated by Cdc15. This mechanism of pathway activation has implications for signal transmission through other kinase cascades and might represent a general principle in scaffold-assisted signaling.

  16. Antiviral activity of tumor-suppressor pathways: clues from molecular piracy by KSHV.

    Science.gov (United States)

    Moore, P S; Chang, Y

    1998-04-01

    A common feature of many tumor viruses is that they possess genes that produce specific proteins to inhibit major cellular tumor-suppressor pathways. Despite intensive studies, the reasons why these diverse and unrelated viruses have independently evolved oncogenes remains obscure. Kaposi-sarcoma-associated herpesvirus (KSHV or HHV8) has pirated a number of recognizable cellular genes that are key to cell survival and proliferation. In this review, we provide an overview of the known activities of these viral genes and show that many of these pirated proteins affect the same cellular pathways targeted by other, unrelated tumor viruses. We speculate that tumor-suppressor pathways are used by the cell as a primary defense against persistent virus infection, in addition to their well-known activity in regulating cell proliferation.

  17. Deubiquitylating enzyme USP9x regulates hippo pathway activity by controlling angiomotin protein turnover

    DEFF Research Database (Denmark)

    Nguyen, Thanh Hung; Andrejeva, Diana; Gupta, Rajat;

    2016-01-01

    The Hippo pathway has been identified as a key barrier for tumorigenesis, acting through downregulation of YAP/TAZ activity. Elevated YAP/TAZ activity has been documented in many human cancers. Ubiquitylation has been shown to play a key role in regulating YAP/TAZ activity through downregulation....../TAZ activity. We demonstrate that USPx regulates ubiquitin-mediated turnover of the YAP inhibitor, Angiomotin. USP9x acts to deubiquitylate Angiomotin at lysine 496, resulting in stabilization of Angiomotin and lower YAP/TAZ activity. USP9x mRNA levels were reduced in several cancers. Clinically, USP9x m...

  18. Altered intrinsic regional spontaneous brain activity in patients with optic neuritis: a resting-state functional magnetic resonance imaging study

    Directory of Open Access Journals (Sweden)

    Shao Y

    2015-12-01

    Full Text Available Yi Shao,1,* Feng-Qin Cai,2,* Yu-Lin Zhong,1 Xin Huang,1,3 Ying Zhang,1 Pei-Hong Hu,1 Chong-Gang Pei,1 Fu-Qing Zhou,2 Xian-Jun Zeng2 1Department of Ophthalmology, 2Department of Radiology, First Affiliated Hospital of Nanchang University, Nanchang, 3Department of Ophthalmology, First People’s Hospital of Jiujiang, Jiujiang, People’s Republic of China *These authors contributed equally to this work Objective: To investigate the underlying regional homogeneity (ReHo in brain-activity deficit in patients with optic neuritis (ON and its relationship with behavioral performance.Materials and methods: In total, twelve patients with ON (four males and eight females and twelve (four males and eight females age-, sex-, and education-matched healthy controls underwent resting-state functional magnetic resonance imaging scans. The ReHo method was used to assess the local features of spontaneous brain activity. Correlation analysis was used to explore the relationship between the observed mean ReHo values of the different brain areas and the visual evoked potential (VEP in patients with ON.Results: Compared with the healthy controls, patients with ON showed lower ReHo in the left cerebellum, posterior lobe, left middle temporal gyrus, right insula, right superior temporal gyrus, left middle frontal gyrus, bilateral anterior cingulate cortex, left superior frontal gyrus, right superior frontal gyrus, and right precentral gyrus, and higher ReHo in the cluster of the left fusiform gyrus and right inferior parietal lobule. Meanwhile, we found that the VEP amplitude of the right eye in patients with ON showed a positive correlation with the ReHo signal value of the left cerebellum posterior lobe (r=0.701, P=0.011, the right superior frontal gyrus (r=0.731, P=0.007, and the left fusiform gyrus (r=0.644, P=0.024. We also found that the VEP latency of the right eye in ON showed a positive correlation with the ReHo signal value of the right insula (r=0.595, P=0

  19. Readout of the intrinsic and extrinsic properties of a stimulus from un-experienced neuronal activities: towards cognitive neuroprostheses.

    Science.gov (United States)

    Farbod Kia, Saba; Åstrand, Elaine; Ibos, Guilhem; Ben Hamed, Suliann

    2011-01-01

    While sensory and motor systems have attracted most of the research effort in the field neuroprosthetics, little attention has been devoted to higher order cortical processes. Here, we propose a first step in the direction of applying neural decoding to the study and manipulation of visuospatial attention, an endogenous process at the interface between sensory and motor functions. To this aim, we investigate whether the offline activity of a population of non-human primate frontal eye field neurons (FEF) in response to an endogenous cue can be readout on a trial by trial basis to provide a precise description of the cue's attributes, namely, its location and identity, but also the allocation of attention following its interpretation. Using a linear decoder, we reach up to 86% correct predictions for the different decoded variables, including the spatial allocation of endogenous attention. We show that the decoding performance drops on incorrect trials, indicating that cue encoding participates to the animal's behavioral performance. Last, we show that the temporal resolution of the decoding influences readout performance. These results are a strong indication of the feasibility of the readout of endogenous variables by standard decoding algorithms, on a suboptimal dataset. However, its validity remains to be proved in a real-time situation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. 2'-Nitroflavone induces apoptosis and modulates mitogen-activated protein kinase pathways in human leukaemia cells.

    Science.gov (United States)

    Cárdenas, Mariano G; Blank, Viviana C; Marder, Mariel N; Roguin, Leonor P

    2012-09-01

    The cytotoxic activity of 2'-nitroflavone was evaluated in different haematological cancer cell lines and its mechanism of action was further studied in HL-60 cells. 2'-Nitroflavone arrested the cell cycle at the G(2)/M phase and induced an apoptotic response characterized by an increase in the sub-G1 fraction of cells, a typical DNA ladder fragmentation, chromatin condensation and the detection of cells stained with Annexin V. Apoptosis was dependent on the activation of at least caspase-8, caspase-9 and caspase-3. The involvement of the death receptor pathway was indicated by the upregulation of both the tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and its death receptor (DR5). We also showed that 2'-nitroflavone increased the expression levels of Bax and induced the release of cytochrome C to cytosol, suggesting the participation of the mitochondria-dependent pathway. When mitogen-activated protein kinases pathways were studied, it was found that p38 and c-Jun NH(2)-terminal kinase (JNK) pathways were activated by 2'-nitroflavone in HL-60 cells, whereas the phosphorylation levels of extracellular signal-regulated kinases (ERK) 1/2 decreased significantly. In addition, whereas both pharmacological inhibition of JNK and downregulation of JNK expression by RNA interference reduced the nitroflavone growth-inhibitory activity and the apoptotic effect, contrasting results were obtained when the ERK1/2 pathway was inhibited, and no effect was observed in the presence of a specific inhibitor of p38 mitogen-activated protein kinase. These findings show for the first time the antitumour action of 2'-nitroflavone in haematological cancer cell lines and suggest that both JNK and ERK1/2 cascades are involved in the apoptotic response induced by 2'-nitroflavone in HL-60 cells.

  1. Concurrent Transient Activation of Wnt/{beta}-Catenin Pathway Prevents Radiation Damage to Salivary Glands

    Energy Technology Data Exchange (ETDEWEB)

    Hai Bo; Yang Zhenhua; Shangguan Lei; Zhao Yanqiu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States); Boyer, Arthur [Department of Radiology, Scott and White Hospital, Temple, Texas (United States); Liu, Fei, E-mail: fliu@medicine.tamhsc.edu [Institute for Regenerative Medicine, Scott and White Hospital, Molecular and Cellular Medicine Department, Texas A and M Health Science Center, Temple, Texas (United States)

    2012-05-01

    Purpose: Many head and neck cancer survivors treated with radiotherapy suffer from permanent impairment of their salivary gland function, for which few effective prevention or treatment options are available. This study explored the potential of transient activation of Wnt/{beta}-catenin signaling in preventing radiation damage to salivary glands in a preclinical model. Methods and Materials: Wnt reporter transgenic mice were exposed to 15 Gy single-dose radiation in the head and neck area to evaluate the effects of radiation on Wnt activity in salivary glands. Transient Wnt1 overexpression in basal epithelia was induced in inducible Wnt1 transgenic mice before together with, after, or without local radiation, and then saliva flow rate, histology, apoptosis, proliferation, stem cell activity, and mRNA expression were evaluated. Results: Radiation damage did not significantly affect activity of Wnt/{beta}-catenin pathway as physical damage did. Transient expression of Wnt1 in basal epithelia significantly activated the Wnt/{beta}-catenin pathway in submandibular glands of male mice but not in those of females. Concurrent transient activation of the Wnt pathway prevented chronic salivary gland dysfunction following radiation by suppressing apoptosis and preserving functional salivary stem/progenitor cells. In contrast, Wnt activation 3 days before or after irradiation did not show significant beneficial effects, mainly due to failure to inhibit acute apoptosis after radiation. Excessive Wnt activation before radiation failed to inhibit apoptosis, likely due to extensive induction of mitosis and up-regulation of proapoptosis gene PUMA while that after radiation might miss the critical treatment window. Conclusion: These results suggest that concurrent transient activation of the Wnt/{beta}-catenin pathway could prevent radiation-induced salivary gland dysfunction.

  2. Beacon Editor: Capturing Signal Transduction Pathways Using the Systems Biology Graphical Notation Activity Flow Language.

    Science.gov (United States)

    Elmarakeby, Haitham; Arefiyan, Mostafa; Myers, Elijah; Li, Song; Grene, Ruth; Heath, Lenwood S

    2017-08-28

    The Beacon Editor is a cross-platform desktop application for the creation and modification of signal transduction pathways using the Systems Biology Graphical Notation Activity Flow (SBGN-AF) language. Prompted by biologists' requests for enhancements, the Beacon Editor includes numerous powerful features for the benefit of creation and presentation.

  3. Activation of the jasmonic acid plant defence pathway alters the composition of rhizosphere bacterial communities.

    Directory of Open Access Journals (Sweden)

    Lilia C Carvalhais

    Full Text Available Jasmonic acid (JA signalling plays a central role in plant defences against necrotrophic pathogens and herbivorous insects, which afflict both roots and shoots. This pathway is also activated following the interaction with beneficial microbes that may lead to induced systemic resistance. Activation of the JA signalling pathway via application of methyl jasmonate (MeJA alters the composition of carbon containing compounds released by roots, which are implicated as key determinants of rhizosphere microbial community structure. In this study, we investigated the influence of the JA defence signalling pathway activation in Arabidopsis thaliana on the structure of associated rhizosphere bacterial communities using 16S rRNA gene amplicon pyrosequencing. Application of MeJA did not directly influence bulk soil microbial communities but significant changes in rhizosphere community composition were observed upon activation of the jasmonate signalling pathway. Our results suggest that JA signalling may mediate plant-bacteria interactions in the soil upon necrotrophic pathogen and herbivorous insect attacks.

  4. DIXDC1 activates the Wnt signaling pathway and promotes gastric cancer cell invasion and metastasis.

    Science.gov (United States)

    Tan, Cong; Qiao, Fan; Wei, Ping; Chi, Yayun; Wang, Weige; Ni, Shujuan; Wang, Qifeng; Chen, Tongzhen; Sheng, Weiqi; Du, Xiang; Wang, Lei

    2016-04-01

    DIXDC1 (Dishevelled-Axin domain containing 1) is a DIX (Dishevelled-Axin) domain-possessing protein that promotes colon cancer cell proliferation and increases the invasion and migration ability of non-small-cell lung cancer via the PI3K pathway. As a positive regulator of the Wnt/β-catenin pathway, the biological role of DIXDC1 in human gastric cancer and the relationship between DIXDC1 and the Wnt pathway are unclear. In the current study, the upregulation of DIXDC1 was detected in gastric cancer and was associated with advanced TNM stage cancer, lymph node metastasis, and poor prognosis. We also found that the overexpression of DIXDC1 could promote the invasion and migration of gastric cancer cells. The upregulation of MMPs and the downregulation of E-cadherin were found to be involved in the process. DIXDC1 enhanced β-catenin nuclear accumulation, which activated the Wnt pathway. Additionally, the inhibition of β-catenin in DIXDC1-overexpressing cells reversed the metastasis promotion effects of DIXDC1. These results demonstrate that the expression of DIXDC1 is associated with poor prognosis of gastric cancer patients and that DIXDC1 promotes gastric cancer invasion and metastasis through the activation of the Wnt pathway; E-cadherin and MMPs are also involved in this process. © 2015 Wiley Periodicals, Inc.

  5. The Akt/mTOR pathway is activated in verrucous carcinoma of the oral cavity.

    Science.gov (United States)

    Chaisuparat, Risa; Limpiwatana, Seehachart; Kongpanitkul, Sanida; Yodsanga, Somchai; Jham, Bruno C

    2016-09-01

    The Akt/mTOR pathway is activated in many malignancies, including oral squamous cell carcinoma (OSCC). However, the role of the Akt/mTOR pathway in oral verrucous carcinoma (OVC), a low-grade variant of OSCC, remains unknown. Thus, the objective of this study was to investigate the activation level of important markers of the Akt/mTOR pathway in OVC and to compare the results with OSCC samples. The expression of p-Akt (Thr308), p-Akt (Ser473), and p-RPS6 was evaluated by immunohistochemistry in 30 OSCC cases, 18 OVC cases, and 30 control cases (normal epithelium overlying fibromas). Statistical analysis was performed to determine the differences in protein expression between samples. All OVC cases were positive for p-Akt (Thr308), p-Akt (Ser473), and p-RPS6. There were significant differences in expression level of all studied proteins between OVC and control, as well as between OVC and OSCC. However, OVC showed significant lower staining scores than OSCC. Our findings demonstrate that the Akt/mTOR pathway is upregulated in OVC, indicating a role for this pathway in the development and progression of this malignancy. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. FlhG employs diverse intrinsic domains and influences FlhF GTPase activity to numerically regulate polar flagellar biogenesis in Campylobacter jejuni.

    Science.gov (United States)

    Gulbronson, Connor J; Ribardo, Deborah A; Balaban, Murat; Knauer, Carina; Bange, Gert; Hendrixson, David R

    2016-01-01

    Flagellation in polar flagellates is one of the rare biosynthetic processes known to be numerically regulated in bacteria. Polar flagellates must spatially and numerically regulate flagellar biogenesis to create flagellation patterns for each species that are ideal for motility. FlhG ATPases numerically regulate polar flagellar biogenesis, yet FlhG orthologs are diverse in motif composition. We discovered that Campylobacter jejuni FlhG is at the center of a multipartite mechanism that likely influences a flagellar biosynthetic step to control flagellar number for amphitrichous flagellation, rather than suppressing activators of flagellar gene transcription as in Vibrio and Pseudomonas species. Unlike other FlhG orthologs, the FlhG ATPase domain was not required to regulate flagellar number in C. jejuni. Instead, two regions of C. jejuni FlhG that are absent or significantly altered in FlhG orthologs are involved in numerical regulation of flagellar biogenesis. Additionally, we found that C. jejuni FlhG influences FlhF GTPase activity, which may mechanistically contribute to flagellar number regulation. Our work suggests that FlhG ATPases divergently evolved in each polarly flagellated species to employ different intrinsic domains and extrinsic effectors to ultimately mediate a common output - precise numerical control of polar flagellar biogenesis required to create species-specific flagellation patterns optimal for motility.

  7. Intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots and their application in the colorimetric detection of H2O2 and glucose.

    Science.gov (United States)

    Lin, Liping; Song, Xinhong; Chen, Yiying; Rong, Mingcong; Zhao, Tingting; Wang, Yiru; Jiang, Yaqi; Chen, Xi

    2015-04-15

    In this paper, the highly intrinsic peroxidase-like catalytic activity of nitrogen-doped graphene quantum dots (N-GQDs) is revealed. This activity was greatly dependent on pH, temperature and H2O2 concentration. The experimental results showed that the stable N-GQDs could be used for the detection of H2O2 and glucose over a wide range of pH and temperature, offering a simple, highly selective and sensitive approach for their colorimetric sensing. The linearity between the analyte concentration and absorption ranged from 20 to 1170 μM for H2O2 and 25 to 375 μM for glucose with a detection limit of 5.3 μM for H2O2 and 16 μM for glucose. This assay was also successfully applied to the detection of glucose concentrations in diluted serum and fruit juice samples. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Metabolic respiration induces AMPK- and Ire1p-dependent activation of the p38-Type HOG MAPK pathway.

    Science.gov (United States)

    Adhikari, Hema; Cullen, Paul J

    2014-10-01

    Evolutionarily conserved mitogen activated protein kinase (MAPK) pathways regulate the response to stress as well as cell differentiation. In Saccharomyces cerevisiae, growth in non-preferred carbon sources (like galactose) induces differentiation to the filamentous cell type through an extracellular-signal regulated kinase (ERK)-type MAPK pathway. The filamentous growth MAPK pathway shares components with a p38-type High Osmolarity Glycerol response (HOG) pathway, which regulates the response to changes in osmolarity. To determine the extent of functional overlap between the MAPK pathways, comparative RNA sequencing was performed, which uncovered an unexpected role for the HOG pathway in regulating the response to growth in galactose. The HOG pathway was induced during growth in galactose, which required the nutrient regulatory AMP-dependent protein kinase (AMPK) Snf1p, an intact respiratory chain, and a functional tricarboxylic acid (TCA) cycle. The unfolded protein response (UPR) kinase Ire1p was also required for HOG pathway activation in this context. Thus, the filamentous growth and HOG pathways are both active during growth in galactose. The two pathways redundantly promoted growth in galactose, but paradoxically, they also inhibited each other's activities. Such cross-modulation was critical to optimize the differentiation response. The human fungal pathogen Candida albicans showed a similar regulatory circuit. Thus, an evolutionarily conserved regulatory axis links metabolic respiration and AMPK to Ire1p, which regulates a differentiation response involving the modulated activity of ERK and p38 MAPK pathways.

  9. Metabolic respiration induces AMPK- and Ire1p-dependent activation of the p38-Type HOG MAPK pathway.

    Directory of Open Access Journals (Sweden)

    Hema Adhikari

    2014-10-01

    Full Text Available Evolutionarily conserved mitogen activated protein kinase (MAPK pathways regulate the response to stress as well as cell differentiation. In Saccharomyces cerevisiae, growth in non-preferred carbon sources (like galactose induces differentiation to the filamentous cell type through an extracellular-signal regulated kinase (ERK-type MAPK pathway. The filamentous growth MAPK pathway shares components with a p38-type High Osmolarity Glycerol response (HOG pathway, which regulates the response to changes in osmolarity. To determine the extent of functional overlap between the MAPK pathways, comparative RNA sequencing was performed, which uncovered an unexpected role for the HOG pathway in regulating the response to growth in galactose. The HOG pathway was induced during growth in galactose, which required the nutrient regulatory AMP-dependent protein kinase (AMPK Snf1p, an intact respiratory chain, and a functional tricarboxylic acid (TCA cycle. The unfolded protein response (UPR kinase Ire1p was also required for HOG pathway activation in this context. Thus, the filamentous growth and HOG pathways are both active during growth in galactose. The two pathways redundantly promoted growth in galactose, but paradoxically, they also inhibited each other's activities. Such cross-modulation was critical to optimize the differentiation response. The human fungal pathogen Candida albicans showed a similar regulatory circuit. Thus, an evolutionarily conserved regulatory axis links metabolic respiration and AMPK to Ire1p, which regulates a differentiation response involving the modulated activity of ERK and p38 MAPK pathways.

  10. Genetic architecture of intrinsic antibiotic susceptibility.

    Directory of Open Access Journals (Sweden)

    Hany S Girgis

    Full Text Available BACKGROUND: Antibiotic exposure rapidly selects for more resistant bacterial strains, and both a drug's chemical structure and a bacterium's cellular network affect the types of mutations acquired. METHODOLOGY/PRINCIPAL FINDINGS: To better characterize the genetic determinants of antibiotic susceptibility, we exposed a transposon-mutagenized library of Escherichia coli to each of 17 antibiotics that encompass a wide range of drug classes and mechanisms of action. Propagating the library for multiple generations with drug concentrations that moderately inhibited the growth of the isogenic parental strain caused the abundance of strains with even minor fitness advantages or disadvantages to change measurably and reproducibly. Using a microarray-based genetic footprinting strategy, we then determined the quantitative contribution of each gene to E. coli's intrinsic antibiotic susceptibility. We found both loci whose removal increased general antibiotic tolerance as well as pathways whose down-regulation increased tolerance to specific drugs and drug classes. The beneficial mutations identified span multiple pathways, and we identified pairs of mutations that individually provide only minor decreases in antibiotic susceptibility but that combine to provide higher tolerance. CONCLUSIONS/SIGNIFICANCE: Our results illustrate that a wide-range of mutations can modulate the activity of many cellular resistance processes and demonstrate that E. coli has a large mutational target size for increasing antibiotic tolerance. Furthermore, the work suggests that clinical levels of antibiotic resistance might develop through the sequential accumulation of chromosomal mutations of small individual effect.

  11. Rac-1 and Raf-1 kinases, components of distinct signaling pathways, activate myotonic dystrophy protein kinase

    Science.gov (United States)

    Shimizu, M.; Wang, W.; Walch, E. T.; Dunne, P. W.; Epstein, H. F.

    2000-01-01

    Myotonic dystrophy protein kinase (DMPK) is a serine-threonine protein kinase encoded by the myotonic dystrophy (DM) locus on human chromosome 19q13.3. It is a close relative of other kinases that interact with members of the Rho family of small GTPases. We show here that the actin cytoskeleton-linked GTPase Rac-1 binds to DMPK, and coexpression of Rac-1 and DMPK activates its transphosphorylation activity in a GTP-sensitive manner. DMPK can also bind Raf-1 kinase, the Ras-activated molecule of the MAP kinase pathway. Purified Raf-1 kinase phosphorylates and activates DMPK. The interaction of DMPK with these distinct signals suggests that it may play a role as a nexus for cross-talk between their respective pathways and may partially explain the remarkable pleiotropy of DM.

  12. 5,10,15,20-Tetrakis(4-carboxyl phenyl)porphyrin–CdS nanocomposites with intrinsic peroxidase-like activity for glucose colorimetric detection

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingyun, E-mail: qyliu@sdust.edu.cn [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Jia, Qingyan; Zhu, Renren; Shao, Qian; Wang, Dongmei; Cui, Peng [School of Chemistry and Environmental Engineering, Shandong University of Science and Technology, Qingdao 266510 (China); Ge, Jiechao, E-mail: jchge2010@mail.ipc.ac.cn [Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-09-01

    Here, we describe the design of a novel mimic peroxidase, nanocomposites composed by 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H{sub 2}TCPP) and cadmium sulfide (CdS). The H{sub 2}TCPP–CdS nanocomposites can catalyze oxidation of substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H{sub 2}O{sub 2} and form a blue product which can be seen by the naked eye in 5 min. The mechanism of the catalytic reaction originated from the generation of hydroxyl radical (·OH), which is a powerful oxidizing agent to oxidize TMB to produce a blue product. Then, we developed a colorimetric method that is highly sensitive and selective to detect glucose, combined with glucose oxidase (GOx). The proposed method allowed the detection of H{sub 2}O{sub 2} concentration in the range of 4 × 10{sup −6}–1.4 × 10{sup −5} M and glucose in the range of 1.875 × 10{sup −5}–1 × 10{sup −4} M with detectable H{sub 2}O{sub 2} concentration as low as 4.6 × 10{sup −7} M and glucose as low as 7.02 × 10{sup −6} M, respectively. The results provided the theoretical basis of practical application in glucose detecting and peroxidase mimetic enzymes. - Graphical abstract: 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H{sub 2}TCPP)–CdS nanohybrids were demonstrated to possess intrinsic peroxidase-like activity and used for a glucose colorimetric sensor. - Highlights: • H{sub 2}TCPP–CdS nanocomposites were synthesized by a facile one step under mild condition. • H{sub 2}TCPP–CdS nanocomposites possess excellent intrinsic peroxidase-like activity. • A sensitive and selective colorimetric sensor for glucose is provided based on H{sub 2}TCPP–CdS nanocomposites. • The generation of hydroxyl radical (·OH) decomposed from H{sub 2}O{sub 2} is contributed to efficient catalytic.

  13. Chitohexaose activates macrophages by alternate pathway through TLR4 and blocks endotoxemia.

    Directory of Open Access Journals (Sweden)

    Santosh K Panda

    Full Text Available Sepsis is a consequence of systemic bacterial infections leading to hyper activation of immune cells by bacterial products resulting in enhanced release of mediators of inflammation. Endotoxin (LPS is a major component of the outer membrane of Gram negative bacteria and a critical factor in pathogenesis of sepsis. Development of antagonists that inhibit the storm of inflammatory molecules by blocking Toll like receptors (TLR has been the main stay of research efforts. We report here that a filarial glycoprotein binds to murine macrophages and human monocytes through TLR4 and activates them through alternate pathway and in the process inhibits LPS mediated classical activation which leads to inflammation associated with endotoxemia. The active component of the nematode glycoprotein mediating alternate activation of macrophages was found to be a carbohydrate residue, Chitohexaose. Murine macrophages and human monocytes up regulated Arginase-1 and released high levels of IL-10 when incubated with chitohexaose. Macrophages of C3H/HeJ mice (non-responsive to LPS failed to get activated by chitohexaose suggesting that a functional TLR4 is critical for alternate activation of macrophages also. Chitohexaose inhibited LPS induced production of inflammatory molecules TNF-α, IL-1β and IL-6 by macropahges in vitro and in vivo in mice. Intraperitoneal injection of chitohexaose completely protected mice against endotoxemia when challenged with a lethal dose of LPS. Furthermore, Chitohexaose was found to reverse LPS induced endotoxemia in mice even 6/24/48 hrs after its onset. Monocytes of subjects with active filarial infection displayed characteristic alternate activation markers and were refractory to LPS mediated inflammatory activation suggesting an interesting possibility of subjects with filarial infections being less prone to develop of endotoxemia. These observations that innate activation of alternate pathway of macrophages by chtx through TLR4 has

  14. Analysis of PIK3CA Mutations and Activation Pathways in Triple Negative Breast Cancer.

    Directory of Open Access Journals (Sweden)

    Paolo Cossu-Rocca

    Full Text Available Triple Negative Breast Cancer (TNBC accounts for 12-24% of all breast carcinomas, and shows worse prognosis compared to other breast cancer subtypes. Molecular studies demonstrated that TNBCs are a heterogeneous group of tumors with different clinical and pathologic features, prognosis, genetic-molecular alterations and treatment responsivity. The PI3K/AKT is a major pathway involved in the regulation of cell survival and proliferation, and is the most frequently altered pathway in breast cancer, apparently with different biologic impact on specific cancer subtypes. The most common genetic abnormality is represented by PIK3CA gene activating mutations, with an overall frequency of 20-40%. The aims of our study were to investigate PIK3CA gene mutations on a large series of TNBC, to perform a wider analysis on genetic alterations involving PI3K/AKT and BRAF/RAS/MAPK pathways and to correlate the results with clinical-pathologic data.PIK3CA mutation analysis was performed by using cobas® PIK3CA Mutation Test. EGFR, AKT1, BRAF, and KRAS genes were analyzed by sequencing. Immunohistochemistry was carried out to identify PTEN loss and to investigate for PI3K/AKT pathways components.PIK3CA mutations were detected in 23.7% of TNBC, whereas no mutations were identified in EGFR, AKT1, BRAF, and KRAS genes. Moreover, we observed PTEN loss in 11.3% of tumors. Deregulation of PI3K/AKT pathways was revealed by consistent activation of pAKT and p-p44/42 MAPK in all PIK3CA mutated TNBC.Our data shows that PIK3CA mutations and PI3K/AKT pathway activation are common events in TNBC. A deeper investigation on specific TNBC genomic abnormalities might be helpful in order to select patients who would benefit from current targeted therapy strategies.

  15. Analysis of multiple sarcoma expression datasets: implications for classification, oncogenic pathway activation and chemotherapy resistance.

    Directory of Open Access Journals (Sweden)

    Panagiotis A Konstantinopoulos

    Full Text Available BACKGROUND: Diagnosis of soft tissue sarcomas (STS is challenging. Many remain unclassified (not-otherwise-specified, NOS or grouped in controversial categories such as malignant fibrous histiocytoma (MFH, with unclear therapeutic value. We analyzed several independent microarray datasets, to identify a predictor, use it to classify unclassifiable sarcomas, and assess oncogenic pathway activation and chemotherapy response. METHODOLOGY/PRINCIPAL FINDINGS: We analyzed 5 independent datasets (325 tumor arrays. We developed and validated a predictor, which was used to reclassify MFH and NOS sarcomas. The molecular "match" between MFH and their predicted subtypes was assessed using genome-wide hierarchical clustering and Subclass-Mapping. Findings were validated in 15 paraffin samples profiled on the DASL platform. Bayesian models of oncogenic pathway activation and chemotherapy response were applied to individual STS samples. A 170-gene predictor was developed and independently validated (80-85% accuracy in all datasets. Most MFH and NOS tumors were reclassified as leiomyosarcomas, liposarcomas and fibrosarcomas. "Molecular match" between MFH and their predicted STS subtypes was confirmed both within and across datasets. This classification revealed previously unrecognized tissue differentiation lines (adipocyte, fibroblastic, smooth-muscle and was reproduced in paraffin specimens. Different sarcoma subtypes demonstrated distinct oncogenic pathway activation patterns, and reclassified MFH tumors shared oncogenic pathway activation patterns with their predicted subtypes. These patterns were associated with predicted resistance to chemotherapeutic agents commonly used in sarcomas. CONCLUSIONS/SIGNIFICANCE: STS profiling can aid in diagnosis through a predictor tracking distinct tissue differentiation in unclassified tumors, and in therapeutic management via oncogenic pathway activation and chemotherapy response assessment.

  16. Mepivacaine-induced contraction involves phosphorylation of extracellular signal-regulated kinase through activation of the lipoxygenase pathway in isolated rat aortic smooth muscle.

    Science.gov (United States)

    Lee, Hyo Min; Ok, Seong-Ho; Sung, Hui-Jin; Eun, So Young; Kim, Hye Jung; Lee, Soo Hee; Kang, Sebin; Shin, Il-Woo; Lee, Heon Keun; Chung, Young-Kyun; Choi, Mun-Jeoung; Bae, Sung Il; Sohn, Ju-Tae

    2013-04-01

    Mepivacaine is an aminoamide local anesthetic with an intermediate duration that intrinsically produces vasoconstriction both in vivo and in vitro. This study investigated the arachidonic acid metabolic pathways involved in mepivacaine-induced contraction, and elucidated the associated cellular mechanism with a particular focus on extracellular signal-regulated kinase (ERK) in endothelium-denuded rat aorta. Isolated rat thoracic aortic rings were suspended for isometric tension recording. Cumulative mepivacaine concentration-response curves were generated in the presence or absence of the following inhibitors: quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, indomethacin, NS-398, SC-560, fluconazole, PD 98059, and verapamil. Mepivacaine-induced ERK phosphorylation, 5-lipoxygenase (5-LOX) expression, and cyclooxygenase (COX)-2 expression in rat aortic smooth muscle cells were detected by Western blot analysis in the presence or absence of inhibitors. Mepivacaine produced tonic contraction in isolated endothelium-denuded rat aorta. Quinacrine dihydrochloride, nordihydroguaiaretic acid, phenidone, AA-861, NS-398, PD 98059, and verapamil attenuated mepivacaine-induced contraction in a concentration-dependent manner. However, fluconazole had no effect on mepivacaine-induced contraction. PD 98059, quinacrine dihydrochloride, nordihydroguaiaretic acid, AA-861, phenidone, and indomethacin attenuated mepivacaine-induced ERK phosphorylation. Mepivacaine upregulated 5-LOX and COX-2 expression. These results suggest that mepivacaine-induced contraction involves ERK activation, which is primarily mediated by the 5-LOX pathway and in part by the COX-2 pathway.

  17. Multiple Reflex Pathways Contribute to Bladder Activation by Intraurethral Stimulation in Persons With Spinal Cord Injury.

    Science.gov (United States)

    McGee, Meredith J; Swan, Brandon D; Danziger, Zachary C; Amundsen, Cindy L; Grill, Warren M

    2017-08-08

    To measure the urodynamic effects of electrical co-stimulation of 2 individual sites in the proximal and distal urethra in persons with spinal cord injury (SCI). This work was motivated by preclinical findings that selective co-stimulation of the cranial urethral sensory nerve and the dorsal genital nerve, which innervate the proximal and distal portions of the urethra, respectively, increased reflex bladder activation and voiding efficiency. Electrical co-stimulation of urethral afferents was conducted in persons with chronic SCI during urodynamics. The effects of different frequencies of intraurethral stimulation at multiple urethral locations on bladder pressure and pelvic floor electromyographic activity were measured. Electromyographic activity indicated that multiple reflex pathways were recruited through stimulation that contributed to bladder activation. The size of reflex bladder contractions evoked by stimulation was dependent on stimulation location or reflex activated and stimulation frequency. Pudendal nerve afferents are a promising target to restore lost bladder control, as stimulation with different frequencies may be used to treat urinary incontinence and increase continent volumes or to generate stimulation-evoked bladder contractions for on-demand voiding. This work identified that co-stimulation of multiple afferent reflex pathways can enhance activation of spinal circuits and may enable improved bladder emptying in SCI when stimulation of a single pathway is not sufficient. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Eviprostat Activates cAMP Signaling Pathway and Suppresses Bladder Smooth Muscle Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Masayuki Takeda

    2013-06-01

    Full Text Available Eviprostat is a popular phytotherapeutic agent for the treatment of lower urinary tract symptoms (LUTS. At present, the signaling mechanisms underlying its therapeutic effects are still poorly understood. Given that cAMP has been reported to suppress cell hyperplasia and hypertrophy in various pathological situations, we asked whether the effect of Eviprostat could be ascribed to the activation of the cAMP signaling pathway. In the study, exposure of cAMP response element (CRE-secreted alkaline phosphatase (SEAP (CRE-SEAP-reporter cells to Eviprostat elevated SEAP secretion, which was associated with an increased phosphorylation of vasodilator-stimulated phosphoprotein (VASP and cAMP-response element-binding protein (CREB, as well as enhanced expression of CRE-regulated protein connexin43, indicating an activation of the cAMP signaling pathway. Consistent with these observations, Eviprostat-induced expression of Cx43 was abolished in the presence of adenylyl cyclase inhibitor SQ22536 or PKA inhibitor H89, whereas it was mimicked by adenylyl cyclase activator, forskolin. Further analysis demonstrated that Eviprostat significantly potentiated the effect of phosphodiesterase 3 (PDE3 inhibitor, but not that of PDE4 inhibitor, on CRE activation. Moreover, Eviprostat suppressed PDGF-induced activation of ERK and Akt and inhibited cell proliferation and hillock formation in both mesangial cells and bladder smooth muscle cells. Collectively, activation of the cAMP signaling pathway could be an important mechanism by which Eviprostat exerts its therapeutic effects for LUTS.

  19. Two zebrafish G2A homologs activate multiple intracellular signaling pathways in acidic environment

    Energy Technology Data Exchange (ETDEWEB)

    Ichijo, Yuta; Mochimaru, Yuta [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Azuma, Morio [Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555 (Japan); Satou, Kazuhiro; Negishi, Jun [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Nakakura, Takashi [Department of Anatomy, Graduate School of Medicine, Teikyo University, 2-11-1 Itabashi-Ku, Tokyo 173-8605 (Japan); Oshima, Natsuki [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan); Mogi, Chihiro; Sato, Koichi [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512 (Japan); Matsuda, Kouhei [Laboratory of Regulatory Biology, Graduate School of Science and Engineering, University of Toyama, 3190-Gofuku, Toyama 930-8555 (Japan); Okajima, Fumikazu [Laboratory of Signal Transduction, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi 371-8512 (Japan); Tomura, Hideaki, E-mail: tomurah@meiji.ac.jp [Laboratory of Cell Signaling Regulation, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571 (Japan)

    2016-01-01

    Human G2A is activated by various stimuli such as lysophosphatidylcholine (LPC), 9-hydroxyoctadecadienoic acid (9-HODE), and protons. The receptor is coupled to multiple intracellular signaling pathways, including the G{sub s}-protein/cAMP/CRE, G{sub 12/13}-protein/Rho/SRE, and G{sub q}-protein/phospholipase C/NFAT pathways. In the present study, we examined whether zebrafish G2A homologs (zG2A-a and zG2A-b) could respond to these stimuli and activate multiple intracellular signaling pathways. We also examined whether histidine residue and basic amino acid residue in the N-terminus of the homologs also play roles similar to those played by human G2A residues if the homologs sense protons. We found that the zG2A-a showed the high CRE, SRE, and NFAT activities, however, zG2A-b showed only the high SRE activity under a pH of 8.0. Extracellular acidification from pH 7.4 to 6.3 ameliorated these activities in zG2A-a-expressing cells. On the other hand, acidification ameliorated the SRE activity but not the CRE and NFAT activities in zG2A-b-expressing cells. LPC or 9-HODE did not modify any activity of either homolog. The substitution of histidine residue at the 174{sup th} position from the N-terminus of zG2A-a to asparagine residue attenuated proton-induced CRE and NFAT activities but not SRE activity. The substitution of arginine residue at the 32nd position from the N-terminus of zG2A-a to the alanine residue also attenuated its high and the proton-induced CRE and NFAT activities. On the contrary, the substitution did not attenuate SRE activity. The substitution of the arginine residue at the 10th position from the N-terminus of zG2A-b to the alanine residue also did not attenuate its high or the proton-induced SRE activity. These results indicate that zebrafish G2A homologs were activated by protons but not by LPC and 9-HODE, and the activation mechanisms of the homologs were similar to those of human G2A. - Highlights: • Zebrafish two G2A homologs are proton

  20. Case study: visualization and analysis of mitogen-activated protein kinase pathways in the literature

    Science.gov (United States)

    Lee, Changsu; Park, Jinah; Park, Jong C.

    2004-06-01

    Data sets of up to 3000 journal abstracts from MEDLINE literature on the keyword combination `MAPK pathway' and `human' are visualized and analyzed for mitogen-activated protein kinase (MAPK) pathways. We have tightly coupled exploratory visualization with information extraction for interactive navigation through scattered information sources, in search of useful facts on MAPK by frequency-based filtering and amplification. Unlike direct database visualization that operates on curated data sets, literature visualization has the advantages of manipulating data sets of a massive scale with a lot less manpower and effectively responding to the fast cycles of the developments in the field.

  1. Activation of Sonic Hedgehog Signaling Pathway in S-type Neuroblastoma Cell Lines

    Institute of Scientific and Technical Information of China (English)

    周昱男; 戴若连; 毛玲; 夏远鹏; 姚玉芳; 杨雪; 胡波

    2010-01-01

    The effects of Sonic hedgehog(Shh) signaling pathway activation on S-type neuroblastoma(NB) cell lines and its role in NB tumorigenesis were investigated.Immunohistochemistry was used to detect the expression of Shh pathway components- Patched1(PTCH1) and Gli1 in 40 human primary NB samples.Western blotting and RT-PCR were used to examine the protein expression and mRNA levels of PTCH1 and Gli1 in three kinds of S-type NB cell lines(SK-N-AS,SK-N-SH and SHEP1),respectively.Exogenous Shh was administrated to ...

  2. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) activates promyogenic signaling pathways, thereby promoting myoblast differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Jin; Go, Ga-Yeon; Yoo, Miran; Kim, Yong Kee [Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of); Seo, Dong-Wan [College of Pharmacy, Dankook University, Cheonan 330-714 (Korea, Republic of); Kang, Jong-Sun [Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Suwon 440-746 (Korea, Republic of); Bae, Gyu-Un, E-mail: gbae@sookmyung.ac.kr [Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women' s University, Seoul 140-742 (Korea, Republic of)

    2016-01-29

    Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) regulates postnatal myogenesis by alleviating myostatin activity, but the molecular mechanisms by which it regulates myogenesis are not fully understood. In this study, we investigate molecular mechanisms of PPARβ/δ in myoblast differentiation. C2C12 myoblasts treated with a PPARβ/δ agonist, GW0742 exhibit enhanced myotube formation and muscle-specific gene expression. GW0742 treatment dramatically activates promyogenic kinases, p38MAPK and Akt, in a dose-dependent manner. GW0742-stimulated myoblast differentiation is mediated by p38MAPK and Akt, since it failed to restore myoblast differentiation repressed by inhibition of p38MAPK and Akt. In addition, GW0742 treatment enhances MyoD-reporter activities. Consistently, overexpression of PPARβ/δ enhances myoblast differentiation accompanied by elevated activation of p38MAPK and Akt. Collectively, these results suggest that PPARβ/δ enhances myoblast differentiation through activation of promyogenic signaling pathways. - Highlights: • A PPARβ/δ agonist, GW0742 promotes myoblast differentiation. • GW0742 activates both p38MAPK and Akt activation in myogenic differentiation. • GW0742 enhances MyoD activity for myogenic differentiation. • Overexpression of PPARβ/δ enhances myoblast differentiation via activating promyogenic signaling pathways. • This is the first finding for agonistic mechanism of PPARβ/δ in myogenesis.

  3. Fucoidan inhibits proliferation of the SKM-1 acute myeloid leukaemia cell line via the activation of apoptotic pathways and production of reactive oxygen species.

    Science.gov (United States)

    Wei, Chunmei; Xiao, Qing; Kuang, Xingyi; Zhang, Tao; Yang, Zesong; Wang, Li

    2015-11-01

    Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukaemia (AML). Fucoidan, a complex sulphated polysaccharide isolated from the cell wall of brown seaweeds, has recently attracted attention for its multiple biological activities and its potential as a novel candidate for cancer therapy. In the present study, the anti‑cancer activity of fucoidan was investigated in the MDS/AML cell line SKM‑1. Fucoidan inhibited proliferation, induced apoptosis and caused G1-phase arrest of the cell cycle in SKM‑1 cells as determined by a cell counting kit 8 assay and flow cytometry. Furthermore, reverse transcription quantitative polymerase chain reaction and western blot analyses indicated that treatment with fucoidan (100 µg/ml for 48 h) activated Fas and caspase‑8 in SKM‑1 cells, which are critical for the extrinsic apoptotic pathway; furthermore, caspase‑9 was activated via decreases in phosphoinositide-3 kinase/Akt signaling as indicated by reduced levels of phosphorylated Akt, suggesting the involvement of the intrinsic apoptotic pathway. In addition, fucoidan treatment of SKM‑1 cells resulted in the generation of reactive oxygen species (ROS) as determined by staining with dichloro-dihydro-fluorescein diacetate. These results suggested that the mechanisms of the anti‑cancer effects of fucoidan in SKM‑1 are closely associated with cell cycle arrest and apoptotic cell death, which partly attributed to the activation of apoptotic pathways and accumulation of intracellular ROS. Our results demonstrated that Fucoidan inhibits proliferation and induces the apoptosis of SKM‑1 cells, which provides substantial therapeutic potential for MDS treatment.

  4. Nucleolus-derived mediators in oncogenic stress response and activation of p53-dependent pathways.

    Science.gov (United States)

    Stępiński, Dariusz

    2016-08-01

    Rapid growth and division of cells, including tumor ones, is correlated with intensive protein biosynthesis. The output of nucleoli, organelles where translational machineries are formed, depends on a rate of particular stages of ribosome production and on accessibility of elements crucial for their effective functioning, including substrates, enzymes as well as energy resources. Different factors that induce cellular stress also often lead to nucleolar dysfunction which results in ribosome biogenesis impairment. Such nucleolar disorders, called nucleolar or ribosomal stress, usually affect cellular functioning which in fact is a result of p53-dependent pathway activation, elicited as a response to stress. These pathways direct cells to new destinations such as cell cycle arrest, damage repair, differentiation, autophagy, programmed cell death or aging. In the case of impaired nucleolar functioning, nucleolar and ribosomal proteins mediate activation of the p53 pathways. They are also triggered as a response to oncogenic factor overexpression to protect tissues and organs against extensive proliferation of abnormal cells. Intentional impairment of any step of ribosome biosynthesis which would direct the cells to these destinations could be a strategy used in anticancer therapy. This review presents current knowledge on a nucleolus, mainly in relation to cancer biology, which is an important and extremely sensitive element of the mechanism participating in cellular stress reaction mediating activation of the p53 pathways in order to counteract stress effects, especially cancer development.

  5. Intrinsic-Density Functionals

    CERN Document Server

    Engel, J

    2006-01-01

    The Hohenberg-Kohn theorem and Kohn-Sham procedure are extended to functionals of the localized intrinsic density of a self-bound system such as a nucleus. After defining the intrinsic-density functional, we modify the usual Kohn-Sham procedure slightly to evaluate the mean-field approximation to the functional, and carefully describe the construction of the leading corrections for a system of fermions in one dimension with a spin-degeneracy equal to the number of particles N. Despite the fact that the corrections are complicated and nonlocal, we are able to construct a local Skyrme-like intrinsic-density functional that, while different from the exact functional, shares with it a minimum value equal to the exact ground-state energy at the exact ground-state intrinsic density, to next-to-leading order in 1/N. We briefly discuss implications for real Skyrme functionals.

  6. Ultraviolet A Enhances Cathepsin L Expression and Activity via JNK Pathway in Human Dermal Fibroblasts

    Science.gov (United States)

    Xu, Qing-Fang; Zheng, Yue; Chen, Jian; Xu, Xin-Ya; Gong, Zi-Jian; Huang, Yun-Fen; Lu, Chun; Maibach, Howard I; Lai, Wei

    2016-01-01

    Background: Cathepsin L (CatL) is a cysteine protease with strong matrix degradation activity that contributes to photoaging. Mannose phosphate-independent sorting pathways mediate ultraviolet A (UVA)-induced alternate trafficking of CatL. Little is known about signaling pathways involved in the regulation of UVA-induced CatL expression and activity. This study aims to investigate whether a single UVA irradiation affects CatL expression and activity and whether mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway is involved in the regulation of UVA-induced CatL expression and activity in human dermal fibroblasts (HDFs). Methods: Primary HDFs were exposed to UVA. Cell proliferation was determined by a cell counting kit. UVA-induced CatL production and activity were studied with quantitative real-time reverse transcription polymerase chain reaction (RT-PCR), Western blotting, and fluorimetric assay in cell lysates collected on three consecutive days after irradiation. Time courses of UVA-activated JNK and p38MAPK signaling were examined by Western blotting. Effects of MAPK inhibitors and knockdown of Jun and Fos on UVA-induced CatL expression and activity were investigated by RT-PCR, Western blotting, and fluorimetric assay. Data were analyzed by one-way analysis of variance. Results: UVA significantly increased CatL gene expression, protein abundance, and enzymatic activity for three consecutive days after irradiation (F = 83.11, 56.14, and 71.19, respectively; all P < 0.05). Further investigation demonstrated phosphorylation of JNK and p38MAPK activated by UVA. Importantly, inactivation of JNK pathway significantly decreased UVA-induced CatL expression and activity, which were not affected by p38MAPK inhibition. Moreover, knockdown of Jun and Fos significantly attenuated basal and UVA-induced CatL expression and activity. Conclusions: UVA enhances CatL production and activity in HDFs, probably by activating JNK and downstreaming AP-1. These

  7. Ultraviolet A Enhances Cathepsin L Expression and Activity via JNK Pathway in Human Dermal Fibroblasts

    Institute of Scientific and Technical Information of China (English)

    Qing-Fang Xu; Yue Zheng; Jian Chen; Xin-Ya Xu; Zi-Jian Gong; Yun-Fen Huang; Chun Lu

    2016-01-01

    Background:Cathepsin L (CatL) is a cysteine protease with strong matrix degradation activity that contributes to photoaging.Mannose phosphate-independent sorting pathways mediate ultraviolet A (UVA)-induced alternate trafficking of CatL.Little is known about signaling pathways involved in the regulation of UVA-induced CatL expression and activity.This study aims to investigate whether a single UVA irradiation affects CatL expression and activity and whether mitogen-activated protein kinase (MAPK)/activator protein-1 (AP-1) pathway is involved in the regulation of UVA-induced CatL expression and activity in human dermal fibroblasts (HDFs).Methods:Primary HDFs were exposed to UVA.Cell proliferation was determined by a cell counting kit.UVA-induced CatL production and activity were studied with quantitative real-time reverse transcription polymerase chain reaction (RT-PCR),Western blotting,and fluorimetric assay in cell lysates collected on three consecutive days after irradiation.Time courses of UVA-activated JNK and p38MAPK signaling were examined by Western blotting.Effects ofMAPK inhibitors and knockdown of Jun and Fos on UVA-induced CatL expression and activity were investigated by RT-PCR,Western blotting,and fluorimetric assay.Data were analyzed by one-way analysis of variance.Results:UVA significantly increased CatL gene expression,protein abundance,and enzymatic activity for three consecutive days after irradiation (F =83.11,56.14,and 71.19,respectively;all P < 0.05).Further investigation demonstrated phosphorylation of JNK and p38MAPK activated by UVA.Importantly,inactivation of JNK pathway significantly decreased UVA-induced CatL expression and activity,which were not affected by p38MAPK inhibition.Moreover,knockdown of Jun and Fos significantly attenuated basal and UVA-induced CatL expression and activity.Conclusions:UVA enhances CatL production and activity in HDFs,probably by activating JNK and downstreaming AP-1.These findings provide a new possible

  8. NF-Y activates genes of metabolic pathways altered in cancer cells.

    Science.gov (United States)

    Benatti, Paolo; Chiaramonte, Maria Luisa; Lorenzo, Mariangela; Hartley, John A; Hochhauser, Daniel; Gnesutta, Nerina; Mantovani, Roberto; Imbriano, Carol; Dolfini, Diletta

    2016-01-12

    The trimeric transcription factor NF-Y binds to the CCAAT box, an element enriched in promoters of genes overexpressed in tumors. Previous studies on the NF-Y regulome identified the general term metabolism as significantly enriched. We dissect here in detail the targeting of metabolic genes by integrating analysis of NF-Y genomic binding and profilings after inactivation of NF-Y subunits in different cell types. NF-Y controls de novo biosynthetic pathways of lipids, teaming up with the master SREBPs regulators. It activates glycolytic genes, but, surprisingly, is neutral or represses mitochondrial respiratory genes. NF-Y targets the SOCG (Serine, One Carbon, Glycine) and Glutamine pathways, as well as genes involved in the biosynthesis of polyamines and purines. Specific cancer-driving nodes are generally under NF-Y control. Altogether, these data delineate a coherent strategy to promote expression of metabolic genes fuelling anaerobic energy production and other anabolic pathways commonly altered in cancer cells.

  9. Retinoblastoma pathway defects show differential ability to activate the constitutive DNA damage response in human tumorigenesis

    DEFF Research Database (Denmark)

    Tort, F.; Bartkova, J.; Sehested, M.

    2006-01-01

    Loss of G(1)-S control and aberrations of the p16(Ink4a)-cyclin D1/cyclin-dependent kinase (CDK) 4(6)-pRb-E2F-cyclin E/CDK2 pathway are common in human cancer. Previous studies showed that oncogene-induced aberrant proliferation, such as on cyclin E overexpression, causes DNA damage and checkpoint...... culture models with differential defects of retinoblastoma pathway components, as overexpression of cyclin D1 or lack of p16(Ink4a), either alone or combined, did not elicit detectable DDR. In contrast, inactivation of pRb, the key component of the pathway, activated the DDR in cultured human or mouse...... cells, analogous to elevated cyclin E. These results highlight differential effect of diverse oncogenic events on driving the 'cancer cell cycles' and their ability to deregulate the replication-driving CDK2 kinase and to alarm the DDR as a potential anticancer barrier in accordance...

  10. Mitogen-activated protein kinase signaling pathways of the tangerine pathotype of Alternaria alternata

    Directory of Open Access Journals (Sweden)

    Kuang-Ren Chung

    2013-06-01

    Full Text Available Mitogen-activated protein kinase (MAPK- mediated signaling pathways have been known to have important functions in eukaryotic organisms. The mechanisms by which the filamentous fungus Alternaria alternata senses and responds to environmental signals have begun to be elucidated. Available data indicate that A. alternata utilizes the Fus3, Hog1 and Slt2 MAPK-mediated signaling pathways, either separately or in a cooperative manner, for conidia formation, resistance to oxidative and osmotic stress, and pathogenesis to citrus. This review provides an overview of our current knowledge of MAPK signaling pathways, in conjunction with the two-component histidine kinase and the Skn7 response regulator, in the tangerine pathotype of A. alternata.

  11. The CEK1-mediated mitogen-activated protein kinase pathway in the fungal pathogen Candida albicans

    Directory of Open Access Journals (Sweden)

    Elvira Román

    2013-06-01

    Full Text Available Mitogen-activated protein kinases (MAPK mediated signal transduction pathways are essential for the adaptation of living organisms to environmental changes. In pathogenic fungi, these MAPK cascades govern the response to many types of situations, and are essential for the successful establishment of the fungus within the host. Therefore, they influence virulence and can be considered as promising therapeutic targets. In the opportunistic pathogen Candida albicans, the Cek1-mediated pathway was identified long time ago as an important virulence determinant in certain animal models. We will review here the recent work that reveals the role that this route plays in three important processes for the cell: osmotic adaptation, fungal morphogenesis and cell wall remodeling. We will also show the complementary (and sometimes opposite roles that under specific circumstances the high osmolarity glycerol and CEK1 pathways play in C. albicans biology, especially in the context of the interaction with the mammalian host.

  12. The Mitogen-Activated Protein Kinase (MAPK) Pathway: Role in Immune Evasion by Trypanosomatids

    Science.gov (United States)

    Soares-Silva, Mercedes; Diniz, Flavia F.; Gomes, Gabriela N.; Bahia, Diana

    2016-01-01

    Leishmania spp. and Trypanosoma cruzi are the causative agents of leishmaniasis and Chagas disease, respectively, two neglected tropical diseases that affect about 25 million people worldwide. These parasites belong to the family Trypanosomatidae, and are both obligate intracellular parasites that manipulate host signaling pathways and the innate immune system to establish infection. Mitogen-activated protein kinases (MAPKs) are serine and threonine protein kinases that are highly conserved in eukaryotes, and are involved in signal transduction pathways that modulate physiological and pathophysiological cell responses. This mini-review highlights existing knowledge concerning the mechanisms that Leishmania spp. and T. cruzi have evolved to target the host’s MAPK signaling pathways and highjack the immune response, and, in this manner, promote parasite maintenance in the host. PMID:26941717

  13. [Acupuncture-moxibustion and mitogen-activated protein kinase signal transduction pathways].

    Science.gov (United States)

    Tiano, Shen; Zhong-Ren, Li

    2012-03-01

    The Literatures on mechanism of acupuncture from the aspect of mitogen-activated protein kinase (MAPK) signal transduction pathways are analyzed in this paper. And the result shows that many acupuncture effects are closely related with the regulation of MAPK signal transduction pathway. However, the current studies only cover limited aspects, and there problems still existed in the experiment designation. Acupuncture and electroacupuncture are often adopted for the treatment group, while moxibustion is not applied for most of them. There are not unified wave model, frequency and stimulation period for electroacupuncture. And the studies still remain in simple confirmation and proper inference. In the future, the domain of researches should be further wid ened and the experiment designation further perfected. Therefore, the therapeutic effect of acupuncture in clinic will be greatly improved through researches on MAPK signal transduction pathway and the production mechanism of acupuncture effect.

  14. Elicitor induced activation of the methylerythritol phosphate pathway toward phytoalexins biosynthesis in rice.

    Science.gov (United States)

    Okada, Atsushi; Shimizu, Takafumi; Okada, Kazunori; Kuzuyama, Tomohisa; Koga, Jinichiro; Shibuya, Naoto; Nojiri, Hideaki; Yamane, Hisakazu

    2007-09-01

    Diterpenoid phytoalexins such as momilactones and phytocassanes are produced via geranylgeranyl diphosphate in suspension-cultured rice cells after treatment with a chitin elicitor. We have previously shown that the production of diterpene hydrocarbons leading to phytoalexins and the expression of related biosynthetic genes are activated in suspension-cultured rice cells upon elicitor treatment. To better understand the elicitor-induced activation of phytoalexin biosynthesis, we conducted microarray analysis using suspension-cultured rice cells collected at various times after treatment with chitin elicitor. Hierarchical cluster analysis revealed two types of early-induced expression (EIE-1, EIE-2) nodes and a late-induced expression (LIE) node that includes genes involved in phytoalexins biosynthesis. The LIE node contains genes that may be responsible for the methylerythritol phosphate (MEP) pathway, a plastidic biosynthetic pathway for isopentenyl diphosphate, an early precursor of phytoalexins. The elicitor-induced expression of these putative MEP pathway genes was confirmed by quantitative reverse-transcription PCR. 1-Deoxy-D: -xylulose 5-phosphate synthase (DXS), 1-deoxy-D: -xylulose 5-phosphate reductoisomerase (DXR), and 4-(cytidine 5'-diphospho)-2-C-methyl-D: -erythritol synthase (CMS), which catalyze the first three committed steps in the MEP pathway, were further shown to have enzymatic activities that complement the growth of E. coli mutants disrupted in the corresponding genes. Application of ketoclomazone and fosmidomycin, inhibitors of DXS and DXR, respectively, repressed the accumulation of diterpene-type phytoalexins in suspension cells treated with chitin elicitor. These results suggest that activation of the MEP pathway is required to supply sufficient terpenoid precursors for the production of phytoalexins in infected rice plants.

  15. Agonist-biased signaling via proteinase activated receptor-2: differential activation of calcium and mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Ramachandran, Rithwik; Mihara, Koichiro; Mathur, Maneesh; Rochdi, Moulay Driss; Bouvier, Michel; Defea, Kathryn; Hollenberg, Morley D

    2009-10-01

    proteolytically revealed TL sequence(s) and the mode of its presentation to the receptor (tethered versus soluble) can confer biased signaling by PAR(2), its arrestin recruitment, and its internalization. Thus, PAR(2) can signal to multiple pathways that are differentially triggered by distinct proteinase-revealed TLs or by synthetic signal-selective activating peptides.

  16. Regulation of microglia activity by glaucocalyxin-A: attenuation of lipopolysaccharide-stimulated neuroinflammation through NF-κB and p38 MAPK signaling pathways.

    Directory of Open Access Journals (Sweden)

    Byung-Wook Kim

    Full Text Available Microglial cells are the resident macrophages and intrinsic arm of the central nervous system innate immune defense. Microglial cells become activated in response to injury, infection, environmental toxins, and other stimuli that threaten neuronal survival. Therefore, regulating microglial activation may have therapeutic benefits that lead to alleviating the progression of inflammatory-mediated neurodegeneration. In the present study, we investigated the effect of glaucocalyxin A (GLA isolated from Rabdosia japonica on the production of pro-inflammatory mediators in lipopolysaccharide (LPS-stimulated primary microglia and BV-2 cells. GLA significantly inhibited LPS-induced production of nitric oxide and reversed the morphological changes in primary microglia. Further, GLA suppressed expression of inducible nitric oxide synthase and cyclooxygenase-2 dose-dependently at the mRNA and protein levels. The production of proinflammatory cytokines such as tumor necrosis factor-α, interleukin-1β (IL-1β, and IL-6 were inhibited by suppressing their transcriptional activity. Furthermore, GLA suppressed nuclear factor-κB activation by blocking degradation of IκB-α and inhibited the induction of lipocalin-2 expression in LPS-stimulated BV-2 cells. Mechanistic study revealed that the inhibitory effects of GLA were accompanied by blocking the p38 mitogen activated protein kinase signaling pathway in activated microglia. In conclusion, given that microglial activation contributes to the pathogenesis of neurodegenerative diseases, GLA could be developed as a potential therapeutic agent for treating microglia-mediated neuroinflammatory diseases.

  17. Telmisartan prevents weight gain and obesity through activation of peroxisome proliferator-activated receptor-delta-dependent pathways

    DEFF Research Database (Denmark)

    He, Hongbo; Yang, Dachun; Ma, Liqun

    2010-01-01

    Telmisartan shows antihypertensive and several pleiotropic effects that interact with metabolic pathways. In the present study we tested the hypothesis that telmisartan prevents adipogenesis in vitro and weight gain in vivo through activation of peroxisome proliferator-activated receptor (PPAR......)-delta-dependent pathways in several tissues. In vitro, telmisartan significantly upregulated PPAR-delta expression in 3T3-L1 preadipocytes in a time- and dose-dependent manner. Other than enhancing PPAR-delta expression by 68.2+/-17.3% and PPAR-delta activity by 102.0+/-9.0%, telmisartan also upregulated PPAR......-gamma expression, whereas neither candesartan nor losartan affected PPAR-delta expression. In vivo, long-term administration of telmisartan significantly reduced visceral fat and prevented high-fat diet-induced obesity in wild-type mice and hypertensive rats but not in PPAR-delta knockout mice. Administration...

  18. Activation of Nrf2-Regulated Glutathione Pathway Genes by Ischemic Preconditioning

    Directory of Open Access Journals (Sweden)

    Karen F. S. Bell

    2011-01-01

    Full Text Available Prophylactic pharmacological activation of astrocytic gene expression driven by the transcription factor Nrf2 boosts antioxidant defences and protects against neuronal loss in ischemia and other disease models. However, the role of Nrf2 in mediating endogenous neuroprotective responses is less clear. We recently showed that Nrf2 is activated by mild oxidative stress in both rodent and human astrocytes. Moreover, brief exposure to ischemic conditions was found to activate Nrf2 both in vivo and in vitro, and this was found to contribute to neuroprotective ischemic preconditioning. Here we show that transient ischemic conditions in vitro and in vivo cause an increase in the expression of Nrf2 target genes associated with the glutathione pathway, including those involved in glutathione biosynthesis and cystine uptake. Taken together, these studies indicate that astrocytic Nrf2 may represent an important mediator of endogenous neuroprotective preconditioning pathways.

  19. The neuroprotective role of acupuncture and activation of the BDNF signaling pathway.

    Science.gov (United States)

    Lin, Dong; De La Pena, Ike; Lin, Lili; Zhou, Shu-Feng; Borlongan, Cesar V; Cao, Chuanhai

    2014-02-21

    Recent studies have been conducted to examine the neuroprotective effects of acupuncture in many neurological disorders. Although the neuroprotective effects of acupuncture has been linked to changes in signaling pathways, accumulating evidence suggest the participation of endogenous biological mediators, such as the neurotrophin (NT) family of proteins, specifically, the brain derived neurotrophic factor (BDNF). Accordingly, acupuncture can inhibit neurodegeneration via expression and activation of BDNF. Moreover, recent studies have reported that acupuncture can increase ATP levels at local stimulated points. We have also demonstrated that acupuncture could activate monocytes and increase the expression of BDNF via the stimulation of ATP. The purpose of this article is to review the recent findings and ongoing studies on the neuroprotective roles of acupuncture and therapeutic implications of acupuncture-induced activation of BDNF and its signaling pathway.

  20. The Neuroprotective Role of Acupuncture and Activation of the BDNF Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Dong Lin

    2014-02-01

    Full Text Available Recent studies have been conducted to examine the neuroprotective effects of acupuncture in many neurological disorders. Although the neuroprotective effects of acupuncture has been linked to changes in signaling pathways, accumulating evidence suggest the participation of endogenous biological mediators, such as the neurotrophin (NT family of proteins, specifically, the brain derived neurotrophic factor (BDNF. Accordingly, acupuncture can inhibit neurodegeneration via expression and activation of BDNF. Moreover, recent studies have reported that acupuncture can increase ATP levels at local stimulated points. We have also demonstrated that acupuncture could activate monocytes and increase the expression of BDNF via the stimulation of ATP. The purpose of this article is to review the recent findings and ongoing studies on the neuroprotective roles of acupuncture and therapeutic implications of acupuncture-induced activation of BDNF and its signaling pathway.

  1. Crystal structure of TNF-α-inducing protein from Helicobacter pylori in active form reveals the intrinsic molecular flexibility for unique DNA-binding.

    Directory of Open Access Journals (Sweden)

    Mingming Gao

    Full Text Available Tipα (TNF-α-inducing protein from Helicobacter pylori is a carcinogenic effector. Studies on this protein revealed that a homodimer linked by a pair of intermolecular disulfide bridges (Cys25-Cys25 and Cys27-Cys27 was absolutely necessary for its biological functions. The activities of Tipα would be abolished when both disulfide bridges were disrupted. The crystal structures of Tipα reported to date, however, were based on inactive, monomeric mutants with their N-terminal, including residues Cys25 and Cys27, truncated. Here we report the crystal structure of H. pylori Tipα protein, TipαN(25, at 2.2Å resolution, in which Cys25 and Cys27 form a pair of inter-chain disulfide bridges linking an active dimer. The disulfide bridges exhibit structural flexibility in the present structure. A series of structure-based mutagenesis, biochemical assays and molecular dynamic simulations on DNA-Tipα interactions reveal that Tipα utilizes the dimeric interface as the DNA-binding site and that residues His60, Arg77 and Arg81 located at the interface are crucial for DNA binding. Tipα could bind to one ssDNA, two ssDNA or one dsDNA in experiments, respectively, in the native or mutant states. The unique DNA-binding activities of Tipα indicate that the intrinsic flexible nature of disulfide bridges could endow certain elasticity to the Tipα dimer for its unique bioactivities. The results shed light on the possible structural mechanism for the functional performances of Tipα.

  2. The FERM-domain protein Expanded regulates Hippo pathway activity via direct interactions with the transcriptional activator Yorkie.

    Science.gov (United States)

    Badouel, Caroline; Gardano, Laura; Amin, Nancy; Garg, Ankush; Rosenfeld, Robyn; Le Bihan, Thierry; McNeill, Helen

    2009-03-01

    The Hippo kinase pathway plays a central role in growth regulation and tumor suppression from flies to man. The Hippo/Mst kinase phosphorylates and activates the NDR family kinase Warts/Lats, which phosphorylates and inhibits the transcriptional activator Yorkie/YAP. Current models place the FERM-domain protein Expanded upstream of Hippo kinase in growth control. To understand how Expanded regulates Hippo pathway activity, we used affinity chromatography and mass spectrometry to identify Expanded-binding proteins. Surprisingly we find that Yorkie is the major Expanded-binding protein in Drosophila S2 cells. Expanded binds Yorkie at endogenous levels via WW-domain-PPxY interactions, independently of Yorkie phosphorylation at S168, which is critical for 14-3-3 binding. Expanded relocalizes Yorkie from the nucleus, abrogating its nuclear activity, and it can regulate growth downstream of warts in vivo. These data lead to a new model whereby Expanded functions downstream of Warts, in concert with 14-3-3 proteins to sequester Yorkie in the cytoplasm, inhibiting growth activity of the Hippo pathway.

  3. Anti-adipogenic activity of berberine is not mediated by the WNT/β-catenin pathway.

    Science.gov (United States)

    Bae, Sungmin; Yoon, Yoosik

    2013-06-01

    Adipogenesis is a differentiation process from preadipocytes to adipocytes, accompanied by the inductions of adipogenic transcription factors and lipid metabolizing enzymes. Among cellular pathways regulating adipogenesis, the WNT/β-catenin pathway is well-known as a suppressor of adipogenesis. Berberine (BBR) is an isoquinoline alkaloid component of the medicinal plants including Coptis chinensis and Coptis japonica with diverse biological activities. This study was conducted to elucidate whether the anti-adipogenic effect of BBR is mediated by the WNT/β-catenin pathway. The results of the present study confirmed that BBR efficiently inhibited adipogenesis of 3T3-L1 cells. However, the anti-adipogenic effects of BBR were not accompanied by the modulations of the WNT/β-catenin pathway members including WNT10B, LRP6, DVL2, GSK3β and β-catenin. When β-catenin was knocked down by its siRNA transfection, the anti-adipogenic effects of BBR including the expression of adipogenic transcription factors and lipid metabolizing enzymes as well as the intracellular fat accumulation were not affected at all. The results of this study showed that the anti-adipogenic effect of BBR is not mediated by the WNT/β-catenin pathway.

  4. Defects in 18 S or 28 S rRNA processing activate the p53 pathway.

    Science.gov (United States)

    Hölzel, Michael; Orban, Mathias; Hochstatter, Julia; Rohrmoser, Michaela; Harasim, Thomas; Malamoussi, Anastassia; Kremmer, Elisabeth; Längst, Gernot; Eick, Dirk

    2010-02-26

    The p53 tumor suppressor pathway is activated by defective ribosome synthesis. Ribosomal proteins are released from the nucleolus and block human double minute-2 (Hdm2) that targets p53 for degradation. However, it remained elusive how abrogation of individual rRNA processing pathways contributes to p53 stabilization. Here, we show that selective inhibition of 18 S rRNA processing provokes accumulation of p53 as efficiently as abrogated 28 S rRNA maturation. We describe hUTP18 as a novel mammalian rRNA processing factor that is specifically involved in 18 S rRNA production. hUTP18 was essential for the cleavage of the 5'-external transcribed spacer leader sequence from the primary polymerase I transcript, but was dispensable for rRNA transcription. Because maturation of the 28 S rRNA was unaffected in hUTP18-depleted cells, our results suggest that the integrity of both the 18 S and 28 S rRNA synthesis pathways can be monitored independently by the p53 pathway. Interestingly, accumulation of p53 after hUTP18 knock down required the ribosomal protein L11. Therefore, cells survey the maturation of the small and large ribosomal subunits by separate molecular routes, which may merge in an L11-dependent signaling pathway for p53 stabilization.

  5. Isoorientin reverts TNF-α-induced insulin resistance in adipocytes activating the insulin signaling pathway.

    Science.gov (United States)

    Alonso-Castro, Angel Josabad; Zapata-Bustos, Rocio; Gómez-Espinoza, Guadalupe; Salazar-Olivo, Luis A

    2012-11-01

    Isoorientin (ISO) is a plant C-glycosylflavonoid with purported antidiabetic effects but unexplored mechanisms of action. To gain insight into its antidiabetic mechanisms, we assayed nontoxic ISO concentrations on the 2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino)-2-deoxy-d-glucose (2-NBDG) uptake by murine 3T3-F442A and human sc adipocytes. In insulin-sensitive adipocytes, ISO stimulated the 2-NBDG uptake by 210% (murine) and 67% (human), compared with insulin treatment. Notably, ISO also induced 2-NBDG uptake in murine (139%) and human (60%) adipocytes made resistant to insulin by treatment with TNF-α, compared with the incorporation induced in these cells by rosiglitazone. ISO induction of glucose uptake in adipocytes was abolished by inhibitors of the insulin signaling pathway. These inhibitors also blocked the proper phosphorylation of insulin signaling pathway components induced by ISO in both insulin-sensitive and insulin-resistant adipocytes. Additionally, ISO stimulated the transcription of genes encoding components of insulin signaling pathway in murine insulin-sensitive and insulin-resistant adipocytes. In summary, we show here that ISO exerts its antidiabetic effects by activating the insulin signaling pathway in adipocytes, reverts the insulin resistance caused in these cells by TNF-α by stimulating the proper phosphorylation of proteins in this signaling pathway, and induces the expression of genes encoding these proteins.

  6. The case for cases B and C: intrinsic hydrogen line ratios of the broad-line region of active galactic nuclei, reddenings, and accretion disc sizes

    CERN Document Server

    Gaskell, C Martin

    2016-01-01

    Low-redshift active galactic nuclei (AGNs) with extremely blue optical spectral indices are shown to have a mean, velocity-averaged, broad-line H$\\alpha$/H$\\beta$ ratio of $\\thickapprox 2.72 \\pm 0.04$, consistent with the Baker-Menzel Case B value. Comparison of a wide range of properties of the very bluest AGNs with those of a luminosity-matched subset of the Dong et al. blue AGN sample indicates that the only difference is the internal reddening. Ultraviolet fluxes are brighter for the bluest AGNs by an amount consistent with the flat AGN reddening curve of Gaskell et al. (2004). The lack of a significant difference in the GALEX (FUV--NUV) colour index strongly rules out a steep SMC-like reddening curve and also argues against an intrinsically harder spectrum. For very blue AGNs the Ly$\\alpha$/H$\\beta$ ratio is also consistent with being the Case B value. The Case B ratios provide strong support for the self-shielded broad-line model of Gaskell, Klimek & Nazarova. It is proposed that the greatly enhance...

  7. Activation of the Erk Pathway Is Required for TGF-β1-Induced EMT In Vitro

    Directory of Open Access Journals (Sweden)

    Lu Xie

    2004-09-01

    Full Text Available Transforming growth factor-β1 (TGF-β1 can be tumorsuppressive through the activation of the Smadmediated signaling pathway. TGF-β1 can also enhance tumor progression by stimulating epithelial-tomesenchymal transition (EMT through additional pathways. EMT is characterized by the acquisition of a fibroblast-like cell morphology, dissolution of tight junctions, disruption of adherence junctions, and formation of actin stress fibers. There is evidence linking the activation of mitogen-activated protein kinase pathways to the induction of TGF-α1-mediated EMT. However, the role of Erk in the induction of TGF-β1-mediated EMT remains unclear. TGF-β1 treatment of normal murine mammary gland (NMuMG epithelial cells resulted in increased gene expression of Ras, Raf, MEK1/2, and Erki/2, as shown by microarray analysis and real-time polymerase chain reaction. Upon 24 and 48 hours of treatment with TGIF-α1, NMuMG and mouse cortical tubule (MCT epithelial cells underwent EMT as shown by changes in cell morphology, delocalization of zonula occludens-1 and E-cadherin from cell-cell junctions, and formation of actin stress fibers. TGF-β1 treatment also resulted in increased levels of phosphorylated Erk and Erk kinase activity. Treatment with an MEK inhibitor, U0126, inhibited increased Erk phosphorylation and kinase activity, and blocked TGF-β1 -induced EMT in both cell lines. These data show that TGF-β1 induces the activation of the Erk signaling pathway, which is required for TGF-β1 -mediated EMT in vitro.

  8. Remote activation of the Wnt/β-catenin signalling pathway using functionalised magnetic particles.

    Science.gov (United States)

    Rotherham, Michael; El Haj, Alicia J

    2015-01-01

    Wnt signalling pathways play crucial roles in developmental biology, stem cell fate and tissue patterning and have become an attractive therapeutic target in the fields of tissue engineering and regenerative medicine. Wnt signalling has also been shown to play a role in human Mesenchymal Stem Cell (hMSC) fate, which have shown potential as a cell therapy in bone and cartilage tissue engineering. Previous work has shown that biocompatible magnetic nanoparticles (MNP) can be used to stimulate specific mechanosensitive membrane receptors and ion channels in vitro and in vivo. Using this strategy, we determined the effects of mechano-stimulation of the Wnt Frizzled receptor on Wnt pathway activation in hMSC. Frizzled receptors were tagged using anti-Frizzled functionalised MNP (Fz-MNP). A commercially available oscillating magnetic bioreactor (MICA Biosystems) was used to mechanically stimulate Frizzled receptors remotely. Our results demonstrate that Fz-MNP can activate Wnt/β-catenin signalling at key checkpoints in the signalling pathway. Immunocytochemistry indicated nuclear localisation of the Wnt intracellular messenger β-catenin after treatment with Fz-MNP. A Wnt signalling TCF/LEF responsive luciferase reporter transfected into hMSC was used to assess terminal signal activation at the nucleus. We observed an increase in reporter activity after treatment with Fz-MNP and this effect was enhanced after mechano-stimulation using the magnetic array. Western blot analysis was used to probe the mechanism of signalling activation and indicated that Fz-MNP signal through an LRP independent mechanism. Finally, the gene expression profiles of stress response genes were found to be similar when cells were treated with recombinant Wnt-3A or Fz-MNP. This study provides proof of principle that Wnt signalling and Frizzled receptors are mechanosensitive and can be remotely activated in vitro. Using magnetic nanoparticle technology it may be possible to modulate Wnt signalling

  9. Remote activation of the Wnt/β-catenin signalling pathway using functionalised magnetic particles.

    Directory of Open Access Journals (Sweden)

    Michael Rotherham

    Full Text Available Wnt signalling pathways play crucial roles in developmental biology, stem cell fate and tissue patterning and have become an attractive therapeutic target in the fields of tissue engineering and regenerative medicine. Wnt signalling has also been shown to play a role in human Mesenchymal Stem Cell (hMSC fate, which have shown potential as a cell therapy in bone and cartilage tissue engineering. Previous work has shown that biocompatible magnetic nanoparticles (MNP can be used to stimulate specific mechanosensitive membrane receptors and ion channels in vitro and in vivo. Using this strategy, we determined the effects of mechano-stimulation of the Wnt Frizzled receptor on Wnt pathway activation in hMSC. Frizzled receptors were tagged using anti-Frizzled functionalised MNP (Fz-MNP. A commercially available oscillating magnetic bioreactor (MICA Biosystems was used to mechanically stimulate Frizzled receptors remotely. Our results demonstrate that Fz-MNP can activate Wnt/β-catenin signalling at key checkpoints in the signalling pathway. Immunocytochemistry indicated nuclear localisation of the Wnt intracellular messenger β-catenin after treatment with Fz-MNP. A Wnt signalling TCF/LEF responsive luciferase reporter transfected into hMSC was used to assess terminal signal activation at the nucleus. We observed an increase in reporter activity after treatment with Fz-MNP and this effect was enhanced after mechano-stimulation using the magnetic array. Western blot analysis was used to probe the mechanism of signalling activation and indicated that Fz-MNP signal through an LRP independent mechanism. Finally, the gene expression profiles of stress response genes were found to be similar when cells were treated with recombinant Wnt-3A or Fz-MNP. This study provides proof of principle that Wnt signalling and Frizzled receptors are mechanosensitive and can be remotely activated in vitro. Using magnetic nanoparticle technology it may be possible to modulate

  10. 4SC-202 activates ASK1-dependent mitochondrial apoptosis pathway to inhibit hepatocellular carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Meili, E-mail: fumeilidrlinyi@tom.com [Department of Infectious Disease, Linyi People' s Hospital, Linyi 276000 (China); Wan, Fuqiang [Department of Head and Neck Surgery, Linyi Tumor Hospital, Linyi 276000 (China); Li, Zhengling [Department of Nursing, Tengzhou Central People' s Hospital, Tengzhou 277500 (China); Zhang, Fenghua [Department of Operating Room, Linyi People' s Hospital, Linyi 276000 (China)

    2016-03-04

    The aim of the present study is to investigate the potential anti-hepatocellular carcinoma (HCC) cell activity by 4SC-202, a novel class I HDAC inhibitor (HDACi). The associated signaling mechanisms were also analyzed. We showed that 4SC-202 treatment induced potent cytotoxic and proliferation–inhibitory activities against established HCC cell lines (HepG2, HepB3, SMMC-7721) and patient-derived primary HCC cells. Further, adding 4SC-202 in HCC cells activated mitochondrial apoptosis pathway, which was evidenced by mitochondrial permeability transition pore (mPTP) opening, cytochrome C cytosol release and caspase-3/-9 activation. Inhibition of this apoptosis pathway, by caspase-3/-9 inhibitors, mPTP blockers, or by shRNA-mediated knockdown of cyclophilin-D (Cyp-D, a key component of mPTP), significantly attenuated 4SC-202-induced HCC cell death and apoptosis. Reversely, over-expression of Cyp-D enhanced 4SC-202's sensitivity in HCC cells. Further studies showed that 4SC-202 induced apoptosis signal-regulating kinase 1 (ASK1) activation, causing it translocation to mitochondria and physical association with Cyp-D. This mitochondrial ASK1-Cyp-D complexation appeared required for mediating 4SC-202-induced apoptosis activation. ASK1 stable knockdown by targeted-shRNAs largely inhibited 4SC-202-induced mPTP opening, cytochrome C release, and following HCC cell apoptotic death. Together, we suggest that 4SC-202 activates ASK1-dependent mitochondrial apoptosis pathway to potently inhibit human HCC cells. - Highlights: • 4SC-202 exerts potent anti-proliferative and cytotoxic activity against established/primary HCC cells. • SC-202-induced anti-HCC cell activity relies on caspase-dependent apoptosis activation. • 4SC-202 activates Cyp-D-dependent mitochondrial apoptosis pathway in HCC cells. • 4SC-202 activates ASK1 in HCC cells, causing it translocation to mitochondria. • Mitochondrial ASK1-Cyp-D complexation mediates 4SC-202's activity in HCC cells.

  11. Decreased Activity of the Protein C Anticoagulant Pathway in the Early Hours of Paroxysmal Atrial Fibrillation.

    Science.gov (United States)

    Negreva, Mariya; Georgiev, Svetoslav; Vitlianova, Katerina

    2017-10-01

    Increased coagulation activity has been established in paroxysmal atrial fibrillation (PAF), but data on the anticoagulant system are scarce. To examine the protein C anticoagulant pathway in the early hours of the disease. Fifty-one patients (26 men and 25 women; mean age 59.84 ± 1.60 years) and 52 controls (26 men and 26 women; mean age 59.50 ± 1.46 years) were selected for the study. Protein C antigen and its activity, total protein S, free protein S and its activity, soluble forms of endothelial protein C receptor (sEPCR), and thrombomodulin (sTM) were examined in the plasma. The indicators were studied in patients between the 2nd and the 24th hour after the onset of arrhythmia. Levels of protein C were significantly elevated in patients compared to controls (111.40% ± 6.66% vs 94.83% ± 4.47%; P = .039). Protein C activity showed significant reduction in PAF (73.13% ± 5.80% vs 103.3% ± 3.80%; P C activity is reduced still in the first hours (until the 24th hour) of PAF clinical manifestation, determining reduced activity of the anticoagulant pathway as a whole. The established low levels of free protein S and its activity as well as low sEPCR and sTM levels are a possible explanation of the changes in protein C activity.

  12. Thiazolidinediones Promote Axonal Growth through the Activation of the JNK Pathway

    Science.gov (United States)

    Quintanilla, Rodrigo A.; Godoy, Juan A.; Alfaro, Ivan; Cabezas, Deny; von Bernhardi, Rommy; Bronfman, Miguel; Inestrosa, Nibaldo C.

    2013-01-01

    The axon is a neuronal process involved in protein transport, synaptic plasticity, and neural regeneration. It has been suggested that their structure and function are profoundly impaired in neurodegenerative diseases. Previous evidence suggest that Peroxisome Proliferator-Activated Receptors-γ (PPARγ promote neuronal differentiation on various neuronal cell types. In addition, we demonstrated that activation of PPARγby thiazolidinediones (TZDs) drugs that selectively activate PPARγ prevent neurite loss and axonal damage induced by amyloid-β (Aβ). However, the potential role of TZDs in axonal elongation and neuronal polarity has not been explored. We report here that the activation of PPARγ by TZDs promoted axon elongation in primary hippocampal neurons. Treatments with different TZDs significantly increased axonal growth and branching area, but no significant effects were observed in neurite elongation compared to untreated neurons. Treatment with PPARγ antagonist (GW 9662) prevented TZDs-induced axonal growth. Recently, it has been suggested that the c-Jun N-terminal kinase (JNK) plays an important role regulating axonal growth and neuronal polarity. Interestingly, in our studies, treatment with TZDs induced activation of the JNK pathway, and the pharmacological blockage of this pathway prevented axon elongation induced by TZDs. Altogether, these results indicate that activation of JNK induced by PPARγactivators stimulates axonal growth and accelerates neuronal polarity. These novel findings may contribute to the understanding of the effects of PPARγ on neuronal differentiation and validate the use of PPARγ activators as therapeutic agents in neurodegenerative diseases. PMID:23741474

  13. Analysis of Pathway Activity in Primary Tumors and NCI60 Cell Lines Using Gene Expression Profiling Data

    Institute of Scientific and Technical Information of China (English)

    Xing-Dong Feng; Jude E. Onyia; Shu-Yu Li; Shu-Guang Huang; Jian-Yong Shou; Bi-Rong Liao; Jonathan M. Yingling; Xiang Ye; Xi Lin; Lawrence M. Gelbert; Eric W. Su

    2007-01-01

    To determine cancer pathway activities in nine types of primary tumors and NCI60 cell lines, we applied an in silico approach by examining gene signatures reflective of consequent pathway activation using gene expression data. Supervised learning approaches predicted that the Ras pathway is active in ~70% of lung adenocarcinomas but inactive in most squamous cell carcinomas, pulmonary carcinoids, and small cell lung carcinomas. In contrast, the TGF-β, TNF-α, Src, Myc, E2F3, and β-catenin pathways are inactive in lung adenocarcinomas. We predicted an active Ras, Myc, Src, and/or E2F3 pathway in significant percentages of breast cancer, colorectal carcinoma, and gliomas. Our results also suggest that Ras may be the most prevailing oncogenic pathway. Additionally, many NCI60 cell lines exhibited a gene signature indicative of an active Ras, Myc, and/or Src, but not E2F3, β-catenin, TNF-α, or TGF-β pathway. To our knowledge, this is the first comprehensive survey of cancer pathway activities in nine major tumor types and the most widely used NCI60 cell lines. The "gene expression pathway signatures" we have defined could facilitate the understanding of molecular mechanisms in cancer development and provide guidance to the selection of appropriate cell lines for cancer research and pharmaceutical compound screening.

  14. The Drosophila PRR GNBP3 assembles effector complexes involved in antifungal defenses independently of its Toll-pathway activation function.

    NARCIS (Netherlands)

    Matskevich, A.A.; Quintin, J.; Ferrandon, D.

    2010-01-01

    The Drosophila Toll-signaling pathway controls the systemic antifungal host response. Gram-negative binding protein 3 (GNBP3), a member of the beta-glucan recognition protein family senses fungal infections and activates this pathway. A second detection system perceives the activity of proteolytic f

  15. Non-specific adsorption of complement proteins affects complement activation pathways of gold nanomaterials.

    Science.gov (United States)

    Quach, Quang Huy; Kah, James Chen Yong

    2017-04-01

    The complement system is a key humoral component of innate immunity, serving as the first line of defense against intruders, including foreign synthetic nanomaterials. Although gold nanomaterials (AuNMs) are widely used in nanomedicine, their immunological response is not well understood. Using AuNMs of three shapes commonly used in biomedical applications: spherical gold nanoparticles, gold nanostars and gold nanorods, we demonstrated that AuNMs activated whole complement system, leading to the formation of SC5b-9 complex. All three complement pathways were simultaneously activated by all the AuNMs. Recognition molecules of the complement system interacted with all AuNMs in vitro, except for l-ficolin, but the correlation between these interactions and corresponding complement pathway activation was only observed in the classical and alternative pathways. We also observed the mediating role of complement activation in cellular uptake of all AuNMs by human U937 promonocytic cells, which expresses complement receptors. Taken together, our results highlighted the potential immunological challenges for clinical applications of AuNMs that were often overlooked.

  16. Peroxisome Proliferator-Activated Receptor and Vitamin D Receptor Signaling Pathways in Cancer Cells

    Energy Technology Data Exchange (ETDEWEB)

    Matsuda, Satoru, E-mail: smatsuda@cc.nara-wu.ac.jp; Kitagishi, Yasuko [Department of Food Science and Nutrition, Nara Women’s University, Kita-Uoya Nishimachi, Nara 630-8506 (Japan)

    2013-10-21

    Peroxisome proliferator-activated receptors (PPARs) are members of the superfamily of nuclear hormone receptors, which respond to specific ligands such as polyunsaturated fatty acids by altering gene expression. Three subtypes of this receptor have been discovered, each evolving to achieve different biological functions. Like other nuclear receptors, the transcriptional activity of PPARs is affected not only by ligand-stimulation, but also by cross-talk with other molecules. For example, both PPARs and the RXRs are ligand-activated transcription factors that coordinately regulate gene expression. In addition, PPARs and vitamin D receptor (VDR) signaling pathways regulate a multitude of genes that are of importance for cellular functions including cell proliferation and cell differentiation. Interaction of the PPARs and VDR signaling pathways has been shown at the level of molecular cross-regulation of their transcription factor. A variety of ligands influencing the PPARs and VDR signaling pathways have been shown to reveal chemopreventive potential by mediating tumor suppressive activities in human cancers. Use of these compounds may represent a potential novel strategy to prevent cancers. This review summarizes the roles of the PPARs and the VDR in pathogenesis and progression of cancer.

  17. A biological pathway linking inflammation and depression: activation of indoleamine 2,3-dioxygenase

    Directory of Open Access Journals (Sweden)

    Christmas DM

    2011-07-01

    Full Text Available David M Christmas, JP Potokar, Simon JC DaviesAcademic Unit of Psychiatry, School of Social and Community Medicine, University of Bristol, Bristol, UK A presentation relating to this manuscript was made by Dr David Christmas at the 9th International Meeting on Clinical Pharmacology in Psychiatry (9th IMCPP in Copenhagen, Denmark in September 2010Abstract: This article highlights the evidence linking depression to increased inflammatory drive and explores putative mechanisms for the association by reviewing both preclinical and clinical literature. The enzyme indoleamine 2,3-dioxygenase is induced by proinflammatory cytokines and may form a link between immune functioning and altered neurotransmission, which results in depression. Increased indoleamine 2,3-dioxygenase activity may cause both tryptophan depletion and increased neurotoxic metabolites of the kynurenine pathway, two alterations which have been hypothesized to cause depression. The tryptophan-kynurenine pathway is comprehensively described with a focus on the evidence linking metabolite alterations to depression. The use of immune-activated groups at high risk of depression have been used to explore these hypotheses; we focus on the studies involving chronic hepatitis C patients receiving interferon-alpha, an immune activating cytokine. Findings from this work have led to novel strategies for the future development of antidepressants including inhibition of indoleamine 2,3-dioxygenase, moderating the cytokines which activate it, or addressing other targets in the kynurenine pathway.Keywords: depression, inflammation, indoleamine 2,3-dioxygenase, kynurenine, serotonin, tryptophan

  18. An artificial HSE promoter for efficient and selective detection of heat shock pathway activity.

    Science.gov (United States)

    Ortner, Viktoria; Ludwig, Alfred; Riegel, Elisabeth; Dunzinger, Sarah; Czerny, Thomas

    2015-03-01

    Detection of cellular stress is of major importance for the survival of cells. During evolution, a network of stress pathways developed, with the heat shock (HS) response playing a major role. The key transcription factor mediating HS signalling activity in mammalian cells is the HS factor HSF1. When activated it binds to the heat shock elements (HSE) in the promoters of target genes like heat shock protein (HSP) genes. They are induced by HSF1 but in addition they integrate multiple signals from different stress pathways. Here, we developed an artificial promoter consisting only of HSEs and therefore selectively reacting to HSF-mediated pathway activation. The promoter is highly inducible but has an extreme low basal level. Direct comparison with the HSPA1A promoter activity indicates that heat-dependent expression can be fully recapitulated by isolated HSEs in human cells. Using this sensitive reporter, we measured the HS response for different temperatures and exposure times. In particular, long heat induction times of 1 or 2 h were compared with short heat durations down to 1 min, conditions typical for burn injuries. We found similar responses to both long and short heat durations but at completely different temperatures. Exposure times of 2 h result in pathway activation at 41 to 44 °C, whereas heat pulses of 1 min lead to a maximum HS response between 47 and 50 °C. The results suggest that the HS response is initiated by a combination of temperature and exposure time but not by a certain threshold temperature.

  19. Targeting notch pathway enhances rapamycin antitumor activity in pancreas cancers through PTEN phosphorylation

    Directory of Open Access Journals (Sweden)

    Vo Kevin

    2011-11-01

    Full Text Available Abstract Background Pancreas cancer is one of most aggressive human cancers with the survival rate for patients with metastatic pancreas cancer at 5-6 months. The poor survival demonstrates a clear need for better target identification, drug development and new therapeutic strategies. Recent discoveries have shown that the role for Notch pathway is important in both development and cancer. Its contribution to oncogenesis also involves crosstalks with other growth factor pathways, such as Akt and its modulator, PTEN. The mounting evidence supporting a role for Notch in cancer promotion and survival suggests that targeting this pathway alone or in combination with other therapeutics represents a promising therapeutic strategy. Results Using a pancreas cancer tissue microarray, we noted that Jagged1, Notch3 and Notch4 are overexpressed in pancreas tumors (26%, 84% and 31% respectively, whereas Notch1 is expressed in blood vessels. While there was no correlation between Notch receptor expression and survival, stage or tumor grade, Notch3 was associated with Jagged1 and EGFR expression, suggesting a unique relationship between Notch3 and Jagged1. Inhibition of the Notch pathway genetically and with gamma-secretase inhibitor (GSI resulted in tumor suppression and enhanced cell death. The observed anti-tumor activity appeared to be through Akt and modulation of PTEN phosphorylation. We discovered that transcriptional regulation of RhoA by Notch is important for PTEN phosphorylation. Finally, the mTOR inhibitor Rapamycin enhanced the effect of GSI on RhoA expression, resulting in down regulation of phospho-Akt and increased in vitro tumor cytotoxity. Conclusions Notch pathway plays an important role in maintaining pancreas tumor phenotype. Targeting this pathway represents a reasonable strategy for the treatment of pancreas cancers. Notch modulates the Akt pathway through regulation of PTEN phosphorylation, an observation that has not been made

  20. Neuropeptide FF activates ERK and NF kappa B signal pathways in differentiated SH-SY5Y cells.

    Science.gov (United States)

    Sun, Yu-long; Zhang, Xiao-yuan; He, Ning; Sun, Tao; Zhuang, Yan; Fang, Quan; Wang, Kai-rong; Wang, Rui

    2012-11-01

    Neuropeptide FF (NPFF) has been reported to play important roles in regulating diverse biological processes. However, little attention has been focused on the downstream signal transduction pathway of NPFF. Here, we used the differentiated neuroblastoma cell line, dSH-SY5Y, which endogenously expresses hNPFF2 receptor, to investigate the signal transduction downstream of NPFF. In particular we investigated the regulation of the extracellular signal-regulated protein kinase (ERK) and the nuclear factor kappa B (NF-κB) pathways by NPFF in these cells. NPFF rapidly and transiently stimulated ERK. H89, a selective inhibitor of cyclic AMP-dependent protein kinase A (PKA), inhibited the NPFF-activated ERK pathway, indicating the involvement of PKA in the NPFF-induced ERK activation. Down-regulation of nitric oxide synthases also attenuated NPFF-induced ERK activation, suggesting that a nitric oxide synthase-dependent pathway is involved. Moreover, the core upstream components of the NF-κB pathway were also significantly activated in response to NPFF, suggesting that the NF-κB pathway is involved in the signal transduction pathway of NPFF. Collectively, these data demonstrate that nitric oxide synthases are involved in the signal transduction pathway of NPFF, and provide the first evidence for the interaction between NPFF and the NF-κB pathway. These advances in our interpretation of the NPFF pathway mechanism will aid the comprehensive understanding of its function and provide novel molecular insight for further study of the NPFF system.

  1. Protein intrinsic disorder in Arabidopsis NAC transcription factors: transcriptional activation by ANAC013 and ANAC046 and their interactions with RCD1.

    Science.gov (United States)

    O'Shea, Charlotte; Kryger, Mikael; Stender, Emil G P; Kragelund, Birthe B; Willemoës, Martin; Skriver, Karen

    2015-01-15

    Protein ID (intrinsic disorder) plays a significant, yet relatively unexplored role in transcription factors (TFs). In the present paper, analysis of the transcription regulatory domains (TRDs) of six phylogenetically representative, plant-specific NAC [no apical meristem, ATAF (Arabidopsis transcription activation factor), cup-shaped cotyledon] TFs shows that the domains are present in similar average pre-molten or molten globule-like states, but have different patterns of order/disorder and MoRFs (molecular recognition features). ANAC046 (Arabidopsis NAC 046) was selected for further studies because of its simple MoRF pattern and its ability to interact with RCD1 (radical-induced cell death 1). Experiments in yeast and thermodynamic characterization suggest that its single MoRF region is sufficient for both transcriptional activation and interaction with RCD1. The remainder of the large regulatory domain is unlikely to contribute to the interaction, since the domain and truncations thereof have similar affinities for RCD1, which are also similar for ANAC013-RCD1 interactions. However, different enthalpic and entropic contributions to binding were revealed for ANAC046 and ANAC013, suggestive of differences in binding mechanisms. Although substitution of both hydrophobic and acidic residues of the ANAC046 MoRF region abolished binding, substitution of other residues, even with α-helix-breaking proline, was less disruptive. Together, the biophysical analyses suggest that RCD1-ANAC046 complex formation does not involve folding-upon-binding, but rather fuzziness or an unknown structure in ANAC046. We suggest that the ANAC046 regulatory domain functions as an entropic chain with a terminal hot spot interacting with RCD1. RCD1, a cellular hub, may be able to interact with many different TFs by exploiting their ID-based flexibility, as demonstrated for its interactions with ANAC046 and ANAC013.

  2. Activation of JNK by TPA promotes apoptosis via PKC pathway in gastric cancer cells

    Institute of Scientific and Technical Information of China (English)

    Yan Chen; Qiao Wu; Si-Yang Song; Wen-Jin Su

    2002-01-01

    AIM: JNK cascade plays an important role in cell proliferation, differentiation and apoptosis. However, the exact function of JNK cascade for apoptosis induction remains largely unknown. In this study, the role of JNK activation stimulated by TPA in the process of apoptosis induction and its signaling transduction pathway in gastric cancer cells were investigated and determined.METHODS: Expressions of mRNA and protein were detected by Northern blot and Western blot. Transcription activity was measured by transient transfection and CAT assay. Apoptotic cells were displayed through staining the nucleus with DAPI and were observed under fluorescence microscope. The apoptotic index was determined by counting 1000 cells randomly.RESULTS: JNK protein was stimulated rapidly by TPA, and reached its highest peak within 3 hr, then decreased in a time-dependent manner, but the expression level of JNK protein induced by TPA was always keeping higher than that in untreated cells. Similar pattern was seen in c-jun mRNA level induced by TPA. TPA significantly activated the transcriptional activity of activator protein-1 with a TPA-closedependent manner. Furthermore, activation of JNK was mediated through PKC pathway. Treatment of cells with PKC specific inhibitor, Wortmannin, led to repression of JNK even in the presence of TPA. More importantly, all these effects were associated with induction of apoptosis in gastric cancer cells. TPA inducted apoptosis obviously in gastric cancer cells. The apoptotic cells became smaller and rounded, and their nuclei became condensation and fragmentation with brightly stained chromatin. However, suppression of JNK by PKC specific inhibitor, Wortmannin, resulted in the decrease of apoptosis induced by TPA in a time-dependent manner, apoptotic index dramatically decreased from 32.56 % to 8.71%.CONCLUSION: TPA stimulates JNK cascade, including upregulation of JNK protein expression level and c-jun mRNA expression level, and activation of activator

  3. Glutathione depletion regulates both extrinsic and intrinsic apoptotic signaling cascades independent from multidrug resistance protein 1

    OpenAIRE

    2014-01-01

    Glutathione (GSH) depletion is an important hallmark of apoptosis. We previously demonstrated that GSH depletion, by its efflux, regulates apoptosis by modulation of executioner caspase activity. However, both the molecular identity of the GSH transporter(s) involved and the signaling cascades regulating GSH loss remain obscure. We sought to determine the role of multidrug resistance protein 1 (MRP1) in GSH depletion and its regulatory role on extrinsic and intrinsic pathways of apoptosis. In...

  4. The optimal corepressor function of nuclear receptor corepressor (NCoR) for peroxisome proliferator-activated receptor γ requires G protein pathway suppressor 2.

    Science.gov (United States)

    Guo, Chun; Li, Yali; Gow, Chien-Hung; Wong, Madeline; Zha, Jikun; Yan, Chunxia; Liu, Hongqi; Wang, Yongjun; Burris, Thomas P; Zhang, Jinsong

    2015-02-06

    Repression of peroxisome proliferator-activated receptor γ (PPARγ)-dependent transcription by the nuclear receptor corepressor (NCoR) is important for homeostatic expression of PPARγ target genes in vivo. The current model states that NCoR-mediated repression requires its direct interaction with PPARγ in the repressive conformation. Previous studies, however, have shown that DNA-bound PPARγ is incompatible with a direct, high-affinity association with NCoR because of the inherent ability of PPARγ to adopt the active conformation. Here we show that NCoR acquires the ability to repress active PPARγ-mediated transcription via G protein pathway suppressor 2 (GPS2), a component of the NCoR corepressor complex. Unlike NCoR, GPS2 can recognize and bind the active state of PPARγ. In GPS2-deficient mouse embryonic fibroblast cells, loss of GPS2 markedly reduces the corepressor function of NCoR for PPARγ, leading to constitutive activation of PPARγ target genes and spontaneous adipogenesis of the cells. GPS2, however, is dispensable for repression mediated by unliganded thyroid hormone receptor α or a PPARγ mutant unable to adopt the active conformation. This study shows that GPS2, although dispensable for the intrinsic repression function of NCoR, can mediate a novel corepressor repression pathway that allows NCoR to directly repress active PPARγ-mediated transcription, which is important for the optimal corepressor function of NCoR for PPARγ. Interestingly, GPS2-dependent repression specifically targets PPARγ but not PPARα or PPARδ. Therefore, GPS2 may serve as a unique target to manipulate PPARγ signaling in diseases. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  5. A novel dithiocarbamate derivative induces cell apoptosis through p53-dependent intrinsic pathway and suppresses the expression of the E6 oncogene of human papillomavirus 18 in HeLa cells.

    Science.gov (United States)

    Li, Yanhong; Qi, Hongxue; Li, Xiaobo; Hou, Xueling; Lu, Xueying; Xiao, Xiangwen

    2015-06-01

    Dithiocarbamates (DTCs) exhibit a broad spectrum of antitumor activities, however, their molecular mechanisms of antitumor have not yet been elucidated. Previously, we have synthesized a series of novel dithiocarbamate derivatives. These DTCs were examined for cytotoxic activities against five human cancer cell lines. In this study, one of dithiocarbamate (DTC1) with higher potential for HeLa cells was chosen to investigate molecular mechanisms for its anti-tumor activities. DTC1 could inhibit proliferation, and highly induce apoptosis in HeLa cells by activating caspase-3, -6 and -9; moreover, activities of caspase-3, -6 and -9 were inhibited by pan-caspase inhibitor, Z-VAD-FMK. Furthermore, DTC1 decreased the levels of Bcl-2 and Bcl-xL, and increased expression of cytosol cytochrome c, Bak, Bax and p53 in a time-dependent manner but had no effect on the level of Rb. It was shown that DTC1 induced HeLa cells apoptosis through a p53-dependent pathway as tested by the wild type p53 inhibitor, pifithrin-α. Additionally, the relative expression of E6 and E7 were evaluated in HPV18-positive (HeLa cells) by real-time PCR and western blotting. The results firstly demonstrated that DTC1 suppressed both expression of E6 mRNA and E6 oncoprotein, but had no effect on the expression of E7 mRNA and protein in HPV18. Our results suggested that DTC1 may serve as novel chemotherapeutic agents in the treatment of cervical cancer and potential anti-HPV virus candidates that merit further studies.

  6. Demonstration of alternative and classical complement pathway activity in colostrum from buffalo (Bubalus bubalis).

    Science.gov (United States)

    Matheswaran, K; Dhinakar Raj, G; Nachimuthu, K

    2003-09-01

    Buffalo colostrum caused lysis of unsensitized red blood cells (RBC) from sheep, goats, rabbits and chickens. RBC from cattle and buffalo were resistant to lysis. That lysis was due to the presence of natural antibodies to these RBC was ruled out since there was no reduction in haemolytic titres even after adsorption with the respective RBC. The addition of EGTA to the diluent had no effect on the haemolytic activity. These findings indicate the presence of alternative complement pathway (ACP) activity in buffalo colostrum. The haemolytic activity of buffalo complement for unsensitized rabbit RBC was reduced to very low levels by heating at 50 degrees C for 45 min. Treatment with zymosan also inhibited the haemolytic activity, while inulin had no effect. The maximum activity of ACP occurred in the presence of 4 mmol/L Mg(2+) in the diluent. The range of ACP activities in colostrum from buffaloes varied from 4.06 to 8.48 CH50 units/ml. Using a standard system for titrating the classical complement pathway and rabbit red blood cells sensitized with goat haemolysin, the range of complement activity in buffalo colostrum was 4.81-6.77 CH50/ml.

  7. The Activation Pathway of Human Rhodopsin in Comparison to Bovine Rhodopsin*

    Science.gov (United States)

    Kazmin, Roman; Rose, Alexander; Szczepek, Michal; Elgeti, Matthias; Ritter, Eglof; Piechnick, Ronny; Hofmann, Klaus Peter; Scheerer, Patrick; Hildebrand, Peter W.; Bartl, Franz J.

    2015-01-01

    Rhodopsin, the photoreceptor of rod cells, absorbs light to mediate the first step of vision by activating the G protein transducin (Gt). Several human diseases, such as retinitis pigmentosa or congenital night blindness, are linked to rhodopsin malfunctions. Most of the corresponding in vivo studies and structure-function analyses (e.g. based on protein x-ray crystallography or spectroscopy) have been carried out on murine or bovine rhodopsin. Because these rhodopsins differ at several amino acid positions from human rhodopsin, we conducted a comprehensive spectroscopic characterization of human rhodopsin in combination with molecular dynamics simulations. We show by FTIR and UV-visible difference spectroscopy that the light-induced transformations of the early photointermediates are very similar. Significant differences between the pigments appear with formation of the still inactive Meta I state and the transition to active Meta II. However, the conformation of Meta II and its activity toward the G protein are essentially the same, presumably reflecting the evolutionary pressure under which the active state has developed. Altogether, our results show that although the basic activation pathways of human and bovine rhodopsin are similar, structural deviations exist in the inactive conformation and during receptor activation, even between closely related rhodopsins. These differences between the well studied bovine or murine rhodopsins and human rhodopsin have to be taken into account when the influence of point mutations on the activation pathway of human rhodopsin are investigated using the bovine or murine rhodopsin template sequences. PMID:26105054

  8. Direct molecular interactions between Beclin 1 and the canonical NFκB activation pathway.

    Science.gov (United States)

    Niso-Santano, Mireia; Criollo, Alfredo; Malik, Shoaib Ahmad; Michaud, Michael; Morselli, Eugenia; Mariño, Guillermo; Lachkar, Sylvie; Galluzzi, Lorenzo; Maiuri, Maria Chaira; Kroemer, Guido

    2012-02-01

    General (macro)autophagy and the activation of NFκB constitute prominent responses to a large array of intracellular and extracellular stress conditions. The depletion of any of the three subunits of the inhibitor of NFκB (IκB) kinase (IKKα, IKKβ, IKKγ/NEMO), each of which is essential for the canonical NFκB activation pathway, limits autophagy induction by physiological or pharmacological triggers, while constitutive active IKK subunits suffice to stimulate autophagy. The activation of IKK usually relies on TGFβ-activated kinase 1 (TAK1), which is also necessary for the optimal induction of autophagy in multiple settings. TAK1 interacts with two structurally similar co-activators, TAK1-binding proteins 2 and 3 (TAB2 and TAB3). Importantly, in resting conditions both TAB2 and TAB3 bind the essential autophagic factor Beclin 1, but not TAK1. In response to pro-autophagic stimuli, TAB2 and TAB3 dissociate from Beclin 1 and engage in stimulatory interactions with TAK1. The inhibitory interaction between TABs and Beclin 1 is mediated by their coiled-coil domains (CCDs). Accordingly, the overexpression of either TAB2 or TAB3 CCD stimulates Beclin 1- and TAK1-dependent autophagy. These results point to the existence of a direct molecular crosstalk between the canonical NFκB activation pathway and the autophagic core machinery that guarantees the coordinated induction of these processes in response to stress.

  9. Activated T cell exosomes promote tumor invasion via Fas signaling pathway.

    Science.gov (United States)

    Cai, Zhijian; Yang, Fei; Yu, Lei; Yu, Zhou; Jiang, Lingling; Wang, Qingqing; Yang, Yunshan; Wang, Lie; Cao, Xuetao; Wang, Jianli

    2012-06-15

    Activated T cells release bioactive Fas ligand (FasL) in exosomes, which subsequently induce self-apoptosis of T cells. However, their potential effects on cell apoptosis in tumors are still unknown. In this study, we purified exosomes expressing FasL from activated CD8(+) T cell from OT-I mice and found that activated T cell exosomes had little effect on apoptosis and proliferation of tumor cells but promoted the invasion of B16 and 3LL cancer cells in vitro via the Fas/FasL pathway. Activated T cell exosomes increased the amount of cellular FLICE inhibitory proteins and subsequently activated the ERK and NF-κB pathways, which subsequently increased MMP9 expression in the B16 murine melanoma cells. In a tumor-invasive model in vivo, we observed that the activated T cell exosomes promoted the migration of B16 tumor cells to lung. Interestingly, pretreatment with FasL mAb significantly reduced the migration of B16 tumor cells to lung. Furthermore, CD8 and FasL double-positive exosomes from tumor mice, but not normal mice, also increased the expression of MMP9 and promoted the invasive ability of B16 murine melanoma and 3LL lung cancer cells. In conclusion, our results indicate that activated T cell exosomes promote melanoma and lung cancer cell metastasis by increasing the expression of MMP9 via Fas signaling, revealing a new mechanism of tumor immune escape.

  10. The bright side of plasmonic gold nanoparticles; activation of Nrf2, the cellular protective pathway

    Science.gov (United States)

    Goldstein, Alona; Soroka, Yoram; Frušić-Zlotkin, Marina; Lewis, Aaron; Kohen, Ron

    2016-06-01

    Plasmonic gold nanoparticles (AuNPs) are widely investigated for cancer therapy, due to their ability to strongly absorb light and convert it to heat and thus selectively destroy tumor cells. In this study we shed light on a new aspect of AuNPs and their plasmonic excitation, wherein they can provide anti-oxidant and anti-inflammatory protection by stimulating the cellular protective Nrf2 pathway. Our study was carried out on cells of the immune system, macrophages, and on skin cells, keratinocytes. A different response to AuNPs was noted in the two types of cells, explained by their distinct uptake profiles. In keratinocytes, the exposure to AuNPs, even at low concentrations, was sufficient to activate the Nrf2 pathway, without any irradiation, due to the presence of free AuNPs inside the cytosol. In contrast, in macrophages, the plasmonic excitation of the AuNPs by a low, non-lethal irradiation dose was required for their release from the constraining vesicles. The mechanism by which AuNPs activate the Nrf2 pathway was studied. Direct and indirect activation were suggested, based on the inherent ability of the AuNPs to react with thiol groups and to generate reactive oxygen species, in particular, under plasmonic excitation. The ability of AuNPs to directly activate the Nrf2 pathway renders them good candidates for treatment of disorders in which the up-regulation of Nrf2 is beneficial, specifically for topical treatment of inflammatory skin diseases.

  11. Thiocoraline alters neuroendocrine phenotype and activates the Notch pathway in MTC-TT cell line.

    Science.gov (United States)

    Tesfazghi, Sara; Eide, Jacob; Dammalapati, Ajitha; Korlesky, Colin; Wyche, Thomas P; Bugni, Tim S; Chen, Herbert; Jaskula-Sztul, Renata

    2013-10-01

    Medullary thyroid cancer (MTC) is an aggressive neuroendocrine tumor (NET). Previous research has shown that activation of Notch signaling has a tumor suppressor role in NETs. The potential therapeutic effect of thiocoraline on the activation of the Notch pathway in an MTC cell line (TT) was investigated. Thiocoraline was isolated from a marine bacterium Verrucosispora sp. MTT assay (3-[4, 5-dimethylthiazole-2-yl]-2, 5-diphenyltetrazolium bromide) was used to determine the IC50 value and to measure cell proliferation. Western blot revealed the expression of Notch isoforms, NET, and cell cycle markers. Cell cycle progression was validated by flow cytometry. The mRNA expression of Notch isoforms and downstream targets were measured using real-time PCR. The IC50 value for thiocoraline treatment in TT cells was determined to be 7.6 nmol/L. Thiocoraline treatment decreased cell proliferation in a dose- and time-dependent manner. The mechanism of growth inhibition was found to be cell cycle arrest in G1 phase. Thiocoraline activated the Notch pathway as demonstrated by the dose-dependent increase in mRNA and protein expression of Notch isoforms. Furthermore, treatment with thiocoraline resulted in changes in the expression of downstream targets of the Notch pathway (HES1, HES2, HES6, HEY1, and HEY2) and reduced expression of NET markers, CgA, and ASCL1. Thiocoraline is a potent Notch pathway activator and an inhibitor of MTC-TT cell proliferation at low nanomolar concentrations. These results provide exciting evidence for the use of thiocoraline as a potential treatment for intractable MTC.

  12. Angiotensin II contributes to renal fibrosis independently of Notch pathway activation.

    Directory of Open Access Journals (Sweden)

    Carolina Lavoz

    Full Text Available Recent studies have described that the Notch signaling pathway is activated in a wide range of renal diseases. Angiotensin II (AngII plays a key role in the progression of kidney diseases. AngII contributes to renal fibrosis by upregulation of profibrotic factors, induction of epithelial mesenchymal transition and accumulation of extracellular matrix proteins. In cultured human tubular epithelial cells the Notch activation by transforming growth factor-β1 (TGF-β1 has been involved in epithelial mesenchymal transition. AngII mimics many profibrotic actions of TGF-β1. For these reasons, our aim was to investigate whether AngII could regulate the Notch/Jagged system in the kidney, and its potential role in AngII-induced responses. In cultured human tubular epithelial cells, TGF-β1, but not AngII, increased the Notch pathway-related gene expression, Jagged-1 synthesis, and caused nuclear translocation of the activated Notch. In podocytes and renal fibroblasts, AngII did not modulate the Notch pathway. In tubular epithelial cells, pharmacological Notch inhibition did not modify AngII-induced changes in epithelial mesenchymal markers, profibrotic factors and extracellular matrix proteins. Systemic infusion of AngII into rats for 2 weeks caused tubulointerstitial fibrosis, but did not upregulate renal expression of activated Notch-1 or Jagged-1, as observed in spontaneously hypertensive rats. Moreover, the Notch/Jagged system was not modulated by AngII type I receptor blockade in the model of unilateral ureteral obstruction in mice. These data clearly indicate that AngII does not regulate the Notch/Jagged signaling system in the kidney, in vivo and in vitro. Our findings showing that the Notch pathway is not involved in AngII-induced fibrosis could provide important information to understand the complex role of Notch system in the regulation of renal regeneration vs damage progression.

  13. Angiotensin II contributes to renal fibrosis independently of Notch pathway activation.

    Science.gov (United States)

    Lavoz, Carolina; Rodrigues-Diez, Raquel; Benito-Martin, Alberto; Rayego-Mateos, Sandra; Rodrigues-Diez, Raúl R; Alique, Matilde; Ortiz, Alberto; Mezzano, Sergio; Egido, Jesús; Ruiz-Ortega, Marta

    2012-01-01

    Recent studies have described that the Notch signaling pathway is activated in a wide range of renal diseases. Angiotensin II (AngII) plays a key role in the progression of kidney diseases. AngII contributes to renal fibrosis by upregulation of profibrotic factors, induction of epithelial mesenchymal transition and accumulation of extracellular matrix proteins. In cultured human tubular epithelial cells the Notch activation by transforming growth factor-β1 (TGF-β1) has been involved in epithelial mesenchymal transition. AngII mimics many profibrotic actions of TGF-β1. For these reasons, our aim was to investigate whether AngII could regulate the Notch/Jagged system in the kidney, and its potential role in AngII-induced responses. In cultured human tubular epithelial cells, TGF-β1, but not AngII, increased the Notch pathway-related gene expression, Jagged-1 synthesis, and caused nuclear translocation of the activated Notch. In podocytes and renal fibroblasts, AngII did not modulate the Notch pathway. In tubular epithelial cells, pharmacological Notch inhibition did not modify AngII-induced changes in epithelial mesenchymal markers, profibrotic factors and extracellular matrix proteins. Systemic infusion of AngII into rats for 2 weeks caused tubulointerstitial fibrosis, but did not upregulate renal expression of activated Notch-1 or Jagged-1, as observed in spontaneously hypertensive rats. Moreover, the Notch/Jagged system was not modulated by AngII type I receptor blockade in the model of unilateral ureteral obstruction in mice. These data clearly indicate that AngII does not regulate the Notch/Jagged signaling system in the kidney, in vivo and in vitro. Our findings showing that the Notch pathway is not involved in AngII-induced fibrosis could provide important information to understand the complex role of Notch system in the regulation of renal regeneration vs damage progression.

  14. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction.

    Science.gov (United States)

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de Los Santos, Berta; Arroyo, Francisco T; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen.

  15. Partial activation of SA- and JA-defensive pathways in strawberry upon Colletotrichum acutatum interaction

    Directory of Open Access Journals (Sweden)

    FRANCISCO AMIL-RUIZ

    2016-07-01

    Full Text Available Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5 and FaPR10 were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen.

  16. Partial Activation of SA- and JA-Defensive Pathways in Strawberry upon Colletotrichum acutatum Interaction

    Science.gov (United States)

    Amil-Ruiz, Francisco; Garrido-Gala, José; Gadea, José; Blanco-Portales, Rosario; Muñoz-Mérida, Antonio; Trelles, Oswaldo; de los Santos, Berta; Arroyo, Francisco T.; Aguado-Puig, Ana; Romero, Fernando; Mercado, José-Ángel; Pliego-Alfaro, Fernando; Muñoz-Blanco, Juan; Caballero, José L.

    2016-01-01

    Understanding the nature of pathogen host interaction may help improve strawberry (Fragaria × ananassa) cultivars. Plant resistance to pathogenic agents usually operates through a complex network of defense mechanisms mediated by a diverse array of signaling molecules. In strawberry, resistance to a variety of pathogens has been reported to be mostly polygenic and quantitatively inherited, making it difficult to associate molecular markers with disease resistance genes. Colletotrichum acutatum spp. is a major strawberry pathogen, and completely resistant cultivars have not been reported. Moreover, strawberry defense network components and mechanisms remain largely unknown and poorly understood. Assessment of the strawberry response to C. acutatum included a global transcript analysis, and acidic hormones SA and JA measurements were analyzed after challenge with the pathogen. Induction of transcripts corresponding to the SA and JA signaling pathways and key genes controlling major steps within these defense pathways was detected. Accordingly, SA and JA accumulated in strawberry after infection. Contrastingly, induction of several important SA, JA, and oxidative stress-responsive defense genes, including FaPR1-1, FaLOX2, FaJAR1, FaPDF1, and FaGST1, was not detected, which suggests that specific branches in these defense pathways (those leading to FaPR1-2, FaPR2-1, FaPR2-2, FaAOS, FaPR5, and FaPR10) were activated. Our results reveal that specific aspects in SA and JA dependent signaling pathways are activated in strawberry upon interaction with C. acutatum. Certain described defense-associated transcripts related to these two known signaling pathways do not increase in abundance following infection. This finding suggests new insight into a specific putative molecular strategy for defense against this pathogen. PMID:27471515

  17. MAPK signaling pathways and HDAC3 activity are disrupted during emerin-null myogenic progenitor differentiation.

    Science.gov (United States)

    Collins, Carol M; Ellis, Joseph; Holaska, James M

    2017-02-10

    Mutations in the gene encoding emerin cause Emery-Dreifuss muscular dystrophy (EDMD). Emerin is an integral inner nuclear membrane protein and a component of the nuclear lamina. EDMD is characterized by skeletal muscle wasting, cardiac conduction defects and tendon contractures. The failure to regenerate skeletal muscle is predicted to contribute to the skeletal muscle pathology of EDMD. We hypothesize muscle regeneration defects are caused by impaired muscle stem cell differentiation. Myogenic progenitors derived from emerin-null mice were used to confirm their impaired differentiation and analyze selected myogenic molecular pathways. Emerin-null progenitors were delayed in their cell cycle exit, had decreased myosin heavy chain (MyHC) expression and formed fewer myotubes. Emerin binds to and activates histone deacetylase 3 (HDAC3). Here we show theophylline, an HDAC3-specific activator, improved myotube formation in emerin-null cells. Addition of the HDAC3-specific inhibitor RGFP966 blocked myotube formation and MyHC expression in wildtype and emerin-null myogenic progenitors, but did not affect cell cycle exit. Downregulation of emerin was previously shown to affect the p38 and ERK MAPK pathways in C2C12 myoblast differentiation. Using a pure population of myogenic progenitors completely lacking emerin expression we show these pathways are also disrupted. ERK inhibition improved MyHC expression in emerin-null cells, but failed to rescue myotube formation or cell cycle exit. p38 MAPK inhibition prevented differentiation in both wildtype and emerin-null progenitors. These results show each of these molecular pathways specifically regulate particular stages of myogenic differentiation in an emerin-dependent manner. Thus, pharmacological targeting of multiple pathways acting at specific differentiation stages may be a better therapeutic approach in the future to rescue muscle regeneration in vivo.

  18. Identification of the visceral pain pathway activated by noxious colorectal distension in mice

    Directory of Open Access Journals (Sweden)

    Melinda eKyloh

    2011-02-01

    Full Text Available In patients with irritable bowel syndrome (IBS, visceral pain is evoked more readily following distension of the colorectum. However, the identity of extrinsic afferent nerve pathway that detects and transmits visceral pain from the colorectum to the spinal cord is unclear. In this study, we identified which extrinsic nerve pathway(s underlies nociception from the colorectum to the spinal cord of rodents. Electromyogram (EMG recordings were made from the transverse oblique abdominal muscles in anesthetized wild type (C57BL/6 mice and acute noxious intraluminal distension (100-120 mmHg applied to the terminal 15mm of rectum to activate visceromotor responses (VMRs. Cutting the lumbar colonic nerves in vivo had no detectable effect on the VMRs evoked by colorectal distension. Lesioning right or left hypogastric nerves also failed to reduce VMRs. However, lesioning left and right branches of the rectal nerves completely abolished the VMRs, regardless of whether the lumbar colonic or hypogastric nerves were severed. Electrical stimulation applied to either the lumbar colonic or hypogastric nerves in vivo, failed to elicit a VMR. In contrast, electrical stimulation (2-5Hz, 0.4ms, 60V applied to the rectum reliably elicited VMRs, which were abolished by selective lesioning of the rectal nerves. DiI retrograde labelling from the colorectum labelled sensory neurons only in dorsal root ganglia (DRG of the lumbosacral region of the spinal cord. In contrast, injection of DiI into the mid to proximal colon labelled sensory neurons in DRG primarily of the lower thoracic level (T8-L4 of the spinal cord. The visceral pain pathway activated by acute noxious distension of the terminal 15 mm of mouse rectum is transmitted predominantly, if not solely, through rectal/pelvic afferent nerve fibres to the spinal cord. The sensory neurons of this spinal afferent pathway lie in the lumbosacral region of the spinal cord, primarily at the level of S2 and S3.

  19. Mechanistic pathways of mercury removal from the organomercurial lyase active site

    Directory of Open Access Journals (Sweden)

    Pedro J. Silva

    2015-07-01

    Full Text Available Bacterial populations present in Hg-rich environments have evolved biological mechanisms to detoxify methylmercury and other organometallic mercury compounds. The most common resistance mechanism relies on the H+-assisted cleavage of the Hg–C bond of methylmercury by the organomercurial lyase MerB. Although the initial reaction steps which lead to the loss of methane from methylmercury have already been studied experimentally and computationally, the reaction steps leading to the removal of Hg2+ from MerB and regeneration of the active site for a new round of catalysis have not yet been elucidated. In this paper, we have studied the final steps of the reaction catalyzed by MerB through quantum chemical computations at the combined MP2/CBS//B3PW91/6-31G(d level of theory. While conceptually simple, these reaction steps occur in a complex potential energy surface where several distinct pathways are accessible and may operate concurrently. The only pathway which clearly emerges as forbidden in our analysis is the one arising from the sequential addition of two thiolates to the metal atom, due to the accumulation of negative charges in the active site. The addition of two thiols, in contrast, leads to two feasible mechanistic possibilities. The most straightforward pathway proceeds through proton transfer from the attacking thiol to Cys159 , leading to its removal from the mercury coordination sphere, followed by a slower attack of a second thiol, which removes Cys96. The other pathway involves Asp99 in an accessory role similar to the one observed earlier for the initial stages of the reaction and affords a lower activation enthalpy, around 14 kcal mol−1, determined solely by the cysteine removal step rather than by the thiol ligation step. Addition of one thiolate to the intermediates arising from either thiol attack occurs without a barrier and produces an intermediate bound to one active site cysteine and from which Hg(SCH32 may be removed

  20. Taurine activates delayed rectifier KV channels via a metabotropic pathway in retinal neurons

    Science.gov (United States)

    Bulley, Simon; Liu, Yufei; Ripps, Harris; Shen, Wen

    2013-01-01

    Taurine is one of the most abundant amino acids in the retina, throughout the CNS, and in heart and muscle cells. In keeping with its broad tissue distribution, taurine serves as a modulator of numerous basic processes, such as enzyme activity, cell development, myocardial function and cytoprotection. Despite this multitude of functional roles, the precise mechanism underlying taurine's actions has not yet been identified. In this study we report findings that indicate a novel role for taurine in the regulation of voltage-gated delayed rectifier potassium (KV) channels in retinal neurons by means of a metabotropic receptor pathway. The metabotropic taurine response was insensitive to the Cl− channel blockers, picrotoxin and strychnine, but it was inhibited by a specific serotonin 5-HT2A receptor antagonist, MDL11939. Moreover, we found that taurine enhanced KV channels via intracellular protein kinase C-mediated pathways. When 5-HT2A receptors were expressed in human embryonic kidney cells, taurine and AL34662, a non-specific 5-HT2 receptor activator, produced a similar regulation of KIR channels. In sum, this study provides new evidence that taurine activates a serotonin system, apparently via 5-HT2A receptors and related intracellular pathways. PMID:23045337

  1. Prebiotic galactooligosaccharides activate mucin and pectic galactan utilization pathways in the human gut symbiont Bacteroides thetaiotaomicron

    Science.gov (United States)

    Lammerts van Bueren, Alicia; Mulder, Marieke; Leeuwen, Sander van; Dijkhuizen, Lubbert

    2017-01-01

    Galactooligosaccharides (GOS) are prebiotic carbohydrates that impart changes in the gut bacterial composition of formula-fed infants to more closely resemble that of breast-fed infants. Consuming human milk oligosaccharides (HMOs) provides specific bacterial strains with an advantage for colonizing the infant intestine. These same effects are seen in infants after GOS consumption, however GOS are very complex mixtures and the underlying molecular mechanisms of how GOS mimic HMOs are relatively unknown. Here we studied the effects of GOS utilization on a prominent gut symbiont, Bacteroides thetaiotaomicron, which has been previously shown to consume HMOs via mucin O-glycan degradation pathways. We show that several pathways for targeting O-mucin glycans are activated in B. thetaiotaomicron by GOS, as well as the galactan utilization sytem. Characterization of the endo-galactanase from this system identified activity on various longer GOS substrates while a subset of GOS compounds were identified as potential activators of mucin glycan metabolism in B. thetaiotaomicron. Our results show that GOS functions as an inducer of mucin-glycan pathways while providing a nutrient source in the form of β-(1 → 4)-galactan. These metabolic features of GOS mixtures may serve to explain the beneficial effects that are seen for GOS supplemented infant formula. PMID:28091546

  2. Natural Products Induce a G Protein-Mediated Calcium Pathway Activating p53 in Cancer Cells

    Science.gov (United States)

    van Ginkel, Paul R.; Yan, Michael B.; Bhattacharya, Saswati; Polans, Arthur S.; Kenealey, Jason D.

    2015-01-01

    Paclitaxel, etoposide, vincristine and doxorubicin are examples of natural products being used as chemotherapeutics but with adverse side effects that limit their therapeutic window. Natural products derived from plants and having low toxicity, such as quercetin, resveratrol, epigallocatechin gallate and piceatannol, have been shown to inhibit tumor cell growth both in vitro and in pre-clinical models of cancer, but their mechanisms of action have not been fully elucidated, thus restricting their use as prototypes for developing synthetic analogs with improved anti-cancer properties. We and others have demonstrated that one of the earliest and consistent events upon exposure of tumor cells to these less toxic natural products is a rise in cytoplasmic calcium, activating several pro-apoptotic pathways. We describe here a G protein/inositol 1,4,5-trisphosphate pathway (InsP3) in MDA-MB-231 human breast cancer cells that mediates between these less toxic natural products and the release of calcium from the endoplasmic reticulum. Further, we demonstrate that this elevation of intracellular calcium modulates p53 activity and the subsequent transcription of several pro-apoptotic genes encoding PIG8, CD95, PIDD, TP53INP, RRM2B, Noxa, p21 and PUMA. We conclude from our findings that less toxic natural products likely bind to a G protein coupled receptor that activates a G protein-mediated and calcium-dependent pathway resulting selectively in tumor cell death. PMID:26341291

  3. Membrane-displayed peptide ligand activates the pheromone response pathway in Saccharomyces cerevisiae.

    Science.gov (United States)

    Hara, Keisuke; Ono, Takuya; Kuroda, Kouichi; Ueda, Mitsuyoshi

    2012-05-01

    The budding yeast, Saccharomyces cerevisiae, is an attractive host for studying G protein-coupled receptors (GPCRs). We developed a system in which a peptide ligand specific for GPCR is displayed on yeast plasma membrane. The model system described here is based on yeast plasma membrane display of an analogue of α-factor, which is a peptide ligand for Ste2p, the GPCR that activates the yeast pheromone response pathway. α-Factor analogues, containing linkers of varying lengths and produced in yeast cells, became attached to the cell plasma membrane by linking to the glycosylphosphatidylinositol (GPI)-anchored plasma membrane protein Yps1p. We were able to demonstrate that an optimized α-factor analogue activated the pheromone response pathway in S. cerevisiae, as assessed by a fluorescent reporter assay. Furthermore, it was shown that linker length strongly influenced signalling pathway activation. To our knowledge, this is the first report documenting functional signalling by a plasma membrane-displayed ligand in S. cerevisiae.

  4. Natural produ