Sample records for activity preferentially inhibits

  1. Brain Cancer Stem Cells Display Preferential Sensitivity to Akt Inhibition

    PubMed Central

    Eyler, Christine E.; Foo, Wen-Chi; LaFiura, Katherine M.; McLendon, Roger E.; Hjelmeland, Anita B.; Rich, Jeremy N.

    2009-01-01

    Malignant brain tumors are among the most lethal cancers, and conventional therapies are largely limited to palliation. Novel therapies targeted against specific molecular pathways may offer improved efficacy and reduced toxicity compared to conventional therapies, but initial clinical trials of molecular targeted agents in brain cancer therapy have been frequently disappointing. In brain tumors and other cancers, subpopulations of tumor cells have recently been characterized by their ability to self-renew and initiate tumors. Although these cancer stem cells, or tumor initiating cells, are often only present in small numbers in human tumors, mounting evidence suggests that cancer stem cells contribute to tumor maintenance and therapeutic resistance. Thus, the development of therapies that target cancer stem cell signal transduction and biologies may improve brain tumor patient survival. We now demonstrate that populations enriched for cancer stem cells are preferentially sensitive to an inhibitor of Akt, a prominent cell survival and invasion signaling node. Treatment with an Akt inhibitor more potently reduced the numbers of viable brain cancer stem cells relative to matched non-stem cancer cells associated with a preferential induction of apoptosis and a suppression of neurosphere formation. Akt inhibition also reduced the motility and invasiveness of all tumor cells but had a greater impact on cancer stem cell behaviors. Furthermore, inhibition of Akt activity in cancer stem cells increased survival of immunocompromised mice bearing human glioma xenografts in vivo. Together, these results suggest that Akt inhibitors may function as effective anti-cancer stem cell therapies. PMID:18802038

  2. Aminophylline preferentially inhibits chloroethylclonidine-insensitive alpha-adrenoceptor-mediated contractions in rat aorta.

    PubMed

    Duarte, J; Pérez-Vizcaíno, F; Zarzuelo, A; Jiménez, J; Tamargo, J

    1993-11-01

    1. In rat thoracic aortae, contractions induced by methoxamine were inhibited by chloroethylclonidine, whereas oxymetazoline-induced contractions, which were more dependent on Ca(2+)-entry, were insensitive to chloroethylclonidine. 2. Aminophylline inhibited the contractions and 45Ca(2+)-uptake induced by both methoxamine and oxymetazoline. However, oxymetazoline-induced contractions were more sensitive to inhibition by aminophylline and D600. 3. Thus, the partial selectivity of aminophylline for the chloroethylclonidine-resistant, highly dependent on extracellular Ca2+, oxymetazoline-mediated responses may be explained by a preferential inhibition of agonist-induced Ca2+ entry as compared to inhibition of other transduction pathways.

  3. Preferential Inhibition of Penicillinase Induction by Oxytetracycline and Its Effect on the Penicillin Susceptibility of Staphylococci

    PubMed Central

    Michael, Thomas M.; Michael, J. Gabriel; Massell, Benedict F.

    1967-01-01

    Exposure of penicillinase-producing staphylococci to a combination of penicillin and oxytetracycline resulted in a synergistic inhibitory activity of the antibiotics on the bacteria. Oxytetracycline was employed in concentrations having little or no effect on bacterial growth. It was found that the synergistic antibacterial effect was caused by the preferential inhibition of penicillinase induction by oxytetracycline, rendering the staphylococci more susceptible to penicillin. PMID:5182245

  4. Glaucocalyxin A Inhibits Platelet Activation and Thrombus Formation Preferentially via GPVI Signaling Pathway

    PubMed Central

    Li, Qiang; Ren, Lijie; Liu, Xiaohui; Chu, Chunjun; Ozaki, Yukio; Zhang, Jian; Zhu, Li

    2013-01-01

    Platelets play a pivotal role in atherothrombosis and the antiplatelet agents have been proved to be useful in preventing onset of acute clinical events including myocardial infarction and stroke. Increasing number of natural compounds has been identified to be potential antiplatelet agents. Here we report the antiplatelet effect of glaucocalyxin A (GLA), an ent-diterpenoid that we isolated and purified from the aerial parts of Rabdosia japonica (Burm. f.) var. glaucocalyx (Maxim.) Hara, and investigate the molecular mechanisms by which GLA inhibits platelet activation and thrombus formation. The effect of GLA on platelet activation was measured using platelets freshly isolated from peripheral blood of healthy donors. Results showed that pretreatment of human platelets with lower concentrations of GLA (0.01μg/ml, 0.1μg/ml) significantly inhibited platelet aggregation induced by collagen (P<0.001) and CRP (P<0.01), a synthetic GPVI ligand, but not by ADP and U46619. Accordingly, GLA inhibited collagen-stimulated tyrosine phosphorylation of Syk, LAT, and phospholipase Cγ2, the signaling events in collagen receptor GPⅥ pathway. GLA also inhibited platelet p-selectin secretion and integrin activation by convulxin, a GPVI selective ligand. Additionally, GLA was found to inhibit low-dose thrombin-induced platelet activation. Using a flow chamber device, GLA was found to attenuate platelet adhesion on collagen surfaces in high shear condition. In vivo studies showed that GLA administration increased the time for complete occlusion upon vascular injury in mice, but did not extend tail-bleeding time when mice were administered with relatively lower doses of GLA. Therefore, the present results provide the molecular basis for the inhibition effect of GLA on platelet activation and its in vivo effect on thrombus formation, suggesting that GLA could potentially be developed as an antiplatelet and antithrombotic agent. PMID:24386454

  5. Deoxyspergualin preferentially inhibits the growth and maturation of anti-CD40-activated surface IgD+ B lymphocytes.

    PubMed

    Morikawa, K; Nemoto, K; Miyawaki, T; Morikawa, S

    1998-06-01

    Deoxyspergualin (DSG), an analogue of spermidin, is a potent immunosuppressive drug with an action quite distinct from that of cyclosporin, rapamycin, or FK506. In this study we investigated the effect of DSG and methyldeoxyspergualin (MeDSG) on the proliferation and differentiation of human B cells stimulated with anti-CD40 MoAb. Highly purified B cells obtained from tonsillar samples were used as target cells. Both agents inhibited the proliferative response of anti-CD40-stimulated B cells in the absence and presence of IL-4, IL-2 or IL-10 in a dose-dependent manner. This inhibitory effect differed markedly among cell populations based on surface IgD expression: strong inhibition of sIgD+ B cells but little inhibition of sIgD- B cells. The drugs also suppressed the production of IgG, IgM and IgA by unfractionated B cells, which suggests that DSG acts against post-switch (sIgD-) B cells. Although the drugs suppressed immunoglobulin synthesis by both sIgD+ and sIgD- B cells, the effect was more marked in the sIgD+ B cells. Analysis of the subclass of IgG secreted by sIgD+ B cells revealed a decline in IgG1 and IgG3 in the presence of DSG. These results suggest that DSG preferentially inhibits the growth and maturation of sIgD+ naive B cells.

  6. Conopeptide Vt3.1 preferentially inhibits BK potassium channels containing β4 subunits via electrostatic interactions.

    PubMed

    Li, Min; Chang, Shan; Yang, Longjin; Shi, Jingyi; McFarland, Kelli; Yang, Xiao; Moller, Alyssa; Wang, Chunguang; Zou, Xiaoqin; Chi, Chengwu; Cui, Jianmin

    2014-02-21

    BK channel β subunits (β1-β4) modulate the function of channels formed by slo1 subunits to produce tissue-specific phenotypes. The molecular mechanism of how the homologous β subunits differentially alter BK channel functions and the role of different BK channel functions in various physiologic processes remain unclear. By studying channels expressed in Xenopus laevis oocytes, we show a novel disulfide-cross-linked dimer conopeptide, Vt3.1 that preferentially inhibits BK channels containing the β4 subunit, which is most abundantly expressed in brain and important for neuronal functions. Vt3.1 inhibits the currents by a maximum of 71%, shifts the G-V relation by 45 mV approximately half-saturation concentrations, and alters both open and closed time of single channel activities, indicating that the toxin alters voltage dependence of the channel. Vt3.1 contains basic residues and inhibits voltage-dependent activation by electrostatic interactions with acidic residues in the extracellular loops of the slo1 and β4 subunits. These results suggest a large interaction surface between the slo1 subunit of BK channels and the β4 subunit, providing structural insight into the molecular interactions between slo1 and β4 subunits. The results also suggest that Vt3.1 is an excellent tool for studying β subunit modulation of BK channels and for understanding the physiological roles of BK channels in neurophysiology.

  7. Preferential inhibition of the plasma membrane NADH oxidase (NOX) activity by diphenyleneiodonium chloride with NADPH as donor

    NASA Technical Reports Server (NTRS)

    Morre, D. James

    2002-01-01

    The cell-surface NADH oxidase (NOX) protein of plant and animal cells will utilize both NADH and NADPH as reduced electron donors for activity. The two activities are distinguished by a differential inhibition by the redox inhibitor diphenyleneiodonium chloride (DPI). Using both plasma membranes and cells, activity with NADPH as donor was markedly inhibited by DPI at submicromolar concentrations, whereas with NADH as donor, DPI was much less effective or had no effect on the activity. The possibility of the inhibition being the result of two different enzymes was eliminated by the use of a recombinant NOX protein. The findings support the concept that NOX proteins serve as terminal oxidases for plasma membrane electron transport involving cytosolic reduced pyridine nucleotides as the natural electron donors and with molecular oxygen as the electron acceptor.

  8. Eugenol and its structural analogs inhibit monoamine oxidase A and exhibit antidepressant-like activity.

    PubMed

    Tao, Guoxin; Irie, Yoshifumi; Li, Dian-Jun; Keung, Wing Ming

    2005-08-01

    Eugenol (1) is an active principle of Rhizoma acori graminei, a medicinal herb used in Asia for the treatment of symptoms reminiscent of Alzheimer's disease (AD). It has been shown to protect neuronal cells from the cytotoxic effect of amyloid beta peptides (Abetas) in cell cultures and exhibit antidepressant-like activity in mice. Results from this study show that eugenol inhibits monoamine oxidase A (MAOA) preferentially with a K(i)=26 microM. It also inhibits MAOB but at much higher concentrations (K(i)=211 microM). In both cases, inhibition is competitive with respect to the monoamine substrate. Survey of compounds structurally related to eugenol has identified a few that inhibit MAOs more potently. Structure activity relationship reveals structural features important for MAOA and MAOB inhibition. Molecular docking experiments were performed to help explain the SAR outcomes. Four of these compounds, two (1, 24) inhibiting MAOA selectively and the other two (19, 21) inhibiting neither MAOA nor MAOB, were tested for antidepressant-like activity using the forced swim test in mice. Results suggest a potential link between the antidepressant activity of eugenol and its MAOA inhibitory activity.

  9. Phloretin differentially inhibits volume-sensitive and cyclic AMP-activated, but not Ca-activated, Cl− channels

    PubMed Central

    Fan, Hai-Tian; Morishima, Shigeru; Kida, Hajime; Okada, Yasunobu

    2001-01-01

    Some phenol derivatives are known to block volume-sensitive Cl− channels. However, effects on the channel of the bisphenol phloretin, which is a known blocker of glucose uniport and anion antiport, have not been examined. In the present study, we investigated the effects of phloretin on volume-sensitive Cl− channels in comparison with cyclic AMP-activated CFTR Cl− channels and Ca2+-activated Cl− channels using the whole-cell patch-clamp technique.Extracellular application of phloretin (over 10 μM) voltage-independently, and in a concentration-dependent manner (IC50 ∼30 μM), inhibited the Cl− current activated by a hypotonic challenge in human epithelial T84, Intestine 407 cells and mouse mammary C127/CFTR cells.In contrast, at 30 μM phloretin failed to inhibit cyclic AMP-activated Cl− currents in T84 and C127/CFTR cells. Higher concentrations (over 100 μM) of phloretin, however, partially inhibited the CFTR Cl− currents in a voltage-dependent manner.At 30 and 300 μM, phloretin showed no inhibitory effect on Ca2+-dependent Cl− currents induced by ionomycin in T84 cells.It is concluded that phloretin preferentially blocks volume-sensitive Cl− channels at low concentrations (below 100 μM) and also inhibits cyclic AMP-activated Cl− channels at higher concentrations, whereas phloretin does not inhibit Ca2+-activated Cl− channels in epithelial cells. PMID:11487521

  10. An Aqueous Extract of Marine Microalgae Exhibits Antimetastatic Activity through Preferential Killing of Suspended Cancer Cells and Anticolony Forming Activity

    PubMed Central

    Somasekharan, Syam Prakash; El-Naggar, Amal; Sorensen, Poul H.

    2016-01-01

    Research on marine natural products as potential anticancer agents is still limited. In the present study, an aqueous extract of a Canadian marine microalgal preparation was assessed for anticancer activities using various assays and cell lines of human cancers, including lung, prostate, stomach, breast, and pancreatic cancers, as well as an osteosarcoma. In vitro, the microalgal extract exhibited marked anticolony forming activity. In addition, it was more toxic, as indicated by increased apoptosis, to nonadherent cells (grown in suspension) than to adherent cells. In vivo, an antimetastatic effect of the extract was observed in NOD-SCID mice carrying subrenal capsule xenografts of PC3 prostate cancer cells. The results of the present study suggest that the antimetastatic effect of the aqueous microalgal extract is based on inhibition of colony forming ability of cancer cells and the preferential killing of suspended cancer cells. Further research aimed at identification of the molecular basis of the anticancer activities of the microalgal extract appears to be warranted. PMID:27656243

  11. Structure-Function Analysis of the Drosophila melanogaster Caudal Transcription Factor Provides Insights into Core Promoter-preferential Activation.

    PubMed

    Shir-Shapira, Hila; Sharabany, Julia; Filderman, Matan; Ideses, Diana; Ovadia-Shochat, Avital; Mannervik, Mattias; Juven-Gershon, Tamar

    2015-07-10

    Regulation of RNA polymerase II transcription is critical for the proper development, differentiation, and growth of an organism. The RNA polymerase II core promoter is the ultimate target of a multitude of transcription factors that control transcription initiation. Core promoters encompass the RNA start site and consist of functional elements such as the TATA box, initiator, and downstream core promoter element (DPE), which confer specific properties to the core promoter. We have previously discovered that Drosophila Caudal, which is a master regulator of genes involved in development and differentiation, is a DPE-specific transcriptional activator. Here, we show that the mouse Caudal-related homeobox (Cdx) proteins (mCdx1, mCdx2, and mCdx4) are also preferential core promoter transcriptional activators. To elucidate the mechanism that enables Caudal to preferentially activate DPE transcription, we performed structure-function analysis. Using a systematic series of deletion mutants (all containing the intact DNA-binding homeodomain) we discovered that the C-terminal region of Caudal contributes to the preferential activation of the fushi tarazu (ftz) Caudal target gene. Furthermore, the region containing both the homeodomain and the C terminus of Caudal was sufficient to confer core promoter-preferential activation to the heterologous GAL4 DNA-binding domain. Importantly, we discovered that Drosophila CREB-binding protein (dCBP) is a co-activator for Caudal-regulated activation of ftz. Strikingly, dCBP conferred the ability to preferentially activate the DPE-dependent ftz reporter to mini-Caudal proteins that were unable to preferentially activate ftz transcription themselves. Taken together, it is the unique combination of dCBP and Caudal that enables the co-activation of ftz in a core promoter-preferential manner. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Arctigenin preferentially induces tumor cell death under glucose deprivation by inhibiting cellular energy metabolism.

    PubMed

    Gu, Yuan; Qi, Chunting; Sun, Xiaoxiao; Ma, Xiuquan; Zhang, Haohao; Hu, Lihong; Yuan, Junying; Yu, Qiang

    2012-08-15

    Selectively eradicating cancer cells with minimum adverse effects on normal cells is a major challenge in the development of anticancer therapy. We hypothesize that nutrient-limiting conditions frequently encountered by cancer cells in poorly vascularized solid tumors might provide an opportunity for developing selective therapy. In this study, we investigated the function and molecular mechanisms of a natural compound, arctigenin, in regulating tumor cell growth. We demonstrated that arctigenin selectively promoted glucose-starved A549 tumor cells to undergo necrosis by inhibiting mitochondrial respiration. In doing so, arctigenin elevated cellular level of reactive oxygen species (ROS) and blocked cellular energy metabolism in the glucose-starved tumor cells. We also demonstrated that cellular ROS generation was caused by intracellular ATP depletion and played an essential role in the arctigenin-induced tumor cell death under the glucose-limiting condition. Furthermore, we combined arctigenin with the glucose analogue 2-deoxyglucose (2DG) and examined their effects on tumor cell growth. Interestingly, this combination displayed preferential cell-death inducing activity against tumor cells compared to normal cells. Hence, we propose that the combination of arctigenin and 2DG may represent a promising new cancer therapy with minimal normal tissue toxicity. Crown Copyright © 2012. Published by Elsevier Inc. All rights reserved.

  13. A semi-synthetic natural product blocks collagen induced arthritis by preferentially suppressing the production of IL-6.

    PubMed

    Kulkarni-Almeida, Asha; Shah, Meet; Jadhav, Mahesh; Hegde, Bindu; Trivedi, Jacqueline; Mishra, Prabhu D; Mahajan, Girish B; Dadarkar, Shruta; Gupte, Ravindra; Dagia, Nilesh

    2016-04-01

    Rheumatoid arthritis (RA), an autoimmune-inflammatory disease is characterized by dysregulation of signal transduction pathways, increased production of pro-inflammatory cytokines, enhanced leukocyte infiltration into synovial microvascular endothelium, extensive formation of hyper proliferative pannus, degradation of cartilage and bone erosion. Several compounds that abrogate cytokine production demonstrate a therapeutic effect in experimental models of arthritis. In this study, we report that a novel semi-synthetic natural product (Compound A) being a preferential IL-6 inhibitor, is efficacious in a murine model of arthritis. In vitro evaluations of pro-inflammatory cytokine production reveal that Compound A preferentially inhibits induced production of IL-6 and not TNF-α from THP-1 cells and isolated human monocytes. Furthermore, Compound A robustly inhibits the spontaneous production of IL-6 from pathologically relevant synovial tissue cells isolated from patients with active RA. In a physiologically relevant assay, Compound A selectively inhibits the activated T cell contact-mediated production of IL-6 from human monocytes. Compound A, at pharmacologically efficacious concentrations, does not significantly curtail the LPS-induced activation of p38 MAPKs. In the collagen-induced arthritis (CIA) mouse model (i) macroscopic observations demonstrate that Compound A, administered subcutaneously in a therapeutic regimen, significantly and dose-dependently inhibits disease associated increases in articular index and paw thickness; (ii) histological analyses of paw tissues reveal that Compound A prominently diminishes joint destruction, hyperproliferative pannus formation and infiltration of inflammatory cells. Collectively, these results provide direct evidence that Compound A, a novel preferential IL-6 inhibitor, suppresses collagen-induced arthritis, and may be a potential therapeutic for treating patients with active RA. Copyright © 2016. Published by Elsevier B.V.

  14. Inhibitory effects of low molecular weight heparin on mediator release by mast cells: preferential inhibition of cytokine production and mast cell-dependent cutaneous inflammation

    PubMed Central

    BARAM, D; RASHKOVSKY, M; HERSHKOVIZ, R; DRUCKER, I; RESHEF, T; BEN-SHITRIT, S; MEKORI, Y A

    1997-01-01

    There has been substantial evidence that suggests that heparin may modulate various aspects of immune function and inflammation in addition to its well known anticoagulant activity. In this regard heparin was found to suppress cell-mediated immune responses or asthmatic reactions to allergen challenge. In the present study we analyse the effects of low molecular weight heparin (LMWH) on mast cell degranulation and cytokine production in vitro and on the elicitation of IgE-mediated mast cell-dependent late cutaneous allergic inflammation in vivo. We have established that LMWH preferentially inhibited tumour necrosis factor-alpha (TNF-α) and IL-4 production without having any significant effect on mast cell degranulation. These effects have been observed in mast cells derived from three different origins that were activated by either immunological or non-immunological stimuli. We have shown that there is inhibition of TNF-α production (and not neutralization of activity), as elimination of the drug after a short preincubation and addition of LMWH to rTNF-α had no effect on TNF-α-mediated cytotoxic activity. These results were also confirmed by ELISA. In vivo, s.c. injection of the LMWH inhibited the leucocyte infiltration associated with the late cutaneous response which followed passive cutaneous anaphylaxis (PCA) reaction, without affecting mast cell numbers or degranulation. These data suggest that LMWH may have an inhibitory role in mast cell-mediated allergic inflammation, and thus might be considered as a possible therapeutic modality. PMID:9409655

  15. Methotrexate as a preferential cyclooxygenase 2 inhibitor in whole blood of patients with rheumatoid arthritis.

    PubMed

    Mello, S B; Barros, D M; Silva, A S; Laurindo, I M; Novaes, G S

    2000-05-01

    To investigate the regulation of whole-blood cyclooxygenase-1 and -2 (COX-2 and COX-1) activities by methotrexate (MTX) in rheumatoid arthritis (RA) patients. Whole blood was withdrawn from nine healthy volunteers, 12 RA patients treated with MTX (RA/MTX) and six RA patients treated with chloroquine (RA/CQ). COX-1 activity was quantified as platelet thromboxane B(2) production in unstimulated blood and COX-2 activity was measured as prostaglandin E(2) (PGE(2)) production in whole blood stimulated with LPS. Thromboxane B(2) and PGE(2) were measured by radioimmunoassay. We studied the drug effect in vitro by direct incubation of MTX with blood obtained from normal donors. Ex vivo assays were performed with blood collected from RA/MTX and RA/CQ patients. The influence of serum factors on enzyme activities was analysed in blood collected from normal donors and incubated with RA/MTX, autologous or heterologous serum. In vitro assays showed no direct action of MTX on the activity of either enzyme. Assays performed with blood from RA/MTX patients showed preferential inhibition of COX-2 activity (PGE(2) = 10.11 +/- 2.42 ng/ml) when compared with blood of normal donors (PGE(2) = 37.7 +/- 4.36 ng/ml; P = 0.001). Inhibition of COX-2 activity was also observed when blood of normal donors was co-incubated with RA/MTX serum. Our results clearly show that the anti-inflammatory action of low-dose MTX is partly mediated by a serum factor induced by MTX or a MTX metabolite that preferentially inhibits the activity of COX-2.

  16. Platelet Surface-Associated Activation and Secretion-Mediated Inhibition of Coagulation Factor XII

    PubMed Central

    Zakharova, Natalia V.; Artemenko, Elena O.; Podoplelova, Nadezhda A.; Sveshnikova, Anastasia N.; Demina, Irina A.; Ataullakhanov, Fazly I.; Panteleev, Mikhail A.

    2015-01-01

    Coagulation factor XII (fXII) is important for arterial thrombosis, but its physiological activation mechanisms are unclear. In this study, we elucidated the role of platelets and platelet-derived material in fXII activation. FXII activation was only observed upon potent platelet stimulation (with thrombin, collagen-related peptide, or calcium ionophore, but not ADP) accompanied by phosphatidylserine exposure and was localised to the platelet surface. Platelets from three patients with grey platelet syndrome did not activate fXII, which suggests that platelet-associated fXII-activating material might be released from α-granules. FXII was preferentially bound by phosphotidylserine-positive platelets and annexin V abrogated platelet-dependent fXII activation; however, artificial phosphotidylserine/phosphatidylcholine microvesicles did not support fXII activation under the conditions herein. Confocal microscopy using DAPI as a poly-phosphate marker did not reveal poly-phosphates associated with an activated platelet surface. Experimental data for fXII activation indicates an auto-inhibition mechanism (k i/k a = 180 molecules/platelet). Unlike surface-associated fXII activation, platelet secretion inhibited activated fXII (fXIIa), particularly due to a released C1-inhibitor. Platelet surface-associated fXIIa formation triggered contact pathway-dependent clotting in recalcified plasma. Computer modelling suggests that fXIIa inactivation was greatly decreased in thrombi under high blood flow due to inhibitor washout. Combined, the surface-associated fXII activation and its inhibition in solution herein may be regarded as a flow-sensitive regulator that can shift the balance between surface-associated clotting and plasma-dependent inhibition, which may explain the role of fXII at high shear and why fXII is important for thrombosis but negligible in haemostasis. PMID:25688860

  17. The preferentially expressed antigen in melanoma (PRAME) inhibits myeloid differentiation in normal hematopoietic and leukemic progenitor cells

    PubMed Central

    Guthrie, Katherine A.; Cummings, Carrie L.; Sabo, Kathleen; Wood, Brent L.; Gooley, Ted; Yang, Taimei; Epping, Mirjam T.; Shou, Yaping; Pogosova-Agadjanyan, Era; Ladne, Paula; Stirewalt, Derek L.; Abkowitz, Janis L.; Radich, Jerald P.

    2009-01-01

    The preferentially expressed antigen in melanoma (PRAME) is expressed in several hematologic malignancies, but either is not expressed or is expressed at only low levels in normal hematopoietic cells, making it a target for cancer therapy. PRAME is a tumor-associated antigen and has been described as a corepressor of retinoic acid signaling in solid tumor cells, but its function in hematopoietic cells is unknown. PRAME mRNA expression increased with chronic myeloid leukemia (CML) disease progression and its detection in late chronic-phase CML patients before tyrosine kinase inhibitor therapy was associated with poorer therapeutic responses and ABL tyrosine kinase domain point mutations. In leukemia cell lines, PRAME protein expression inhibited granulocytic differentiation only in cell lines that differentiate along this lineage after all-trans retinoic acid (ATRA) exposure. Forced PRAME expression in normal hematopoietic progenitors, however, inhibited myeloid differentiation both in the presence and absence of ATRA, and this phenotype was reversed when PRAME was silenced in primary CML progenitors. These observations suggest that PRAME inhibits myeloid differentiation in certain myeloid leukemias, and that its function in these cells is lineage and phenotype dependent. Lastly, these observations suggest that PRAME is a target for both prognostic and therapeutic applications. PMID:19625708

  18. Omeprazole preferentially inhibits the metabolism of (+)-(S)-citalopram in healthy volunteers.

    PubMed

    Rocha, Adriana; Coelho, Eduardo B; Sampaio, Stefânia A; Lanchote, Vera L

    2010-07-01

    Citalopram (CITA) pharmacokinetics are enantioselective in healthy volunteers and the metabolism of (+)-(S)-CITA to (+)-(S)-DCITA is dependent on CYP2C19. Omeprazole is a potent CYP2C19 inhibitor. This study indicates that omeprazole induces a loss of enantioselectivity in the CITA pharmacokinetics because of the selective inhibition of (+)-(S)-CITA metabolism. The study assessed the influence of omeprazole on the kinetic disposition of the (+)-(S)-citalopram (CITA) and (-)-(R)-CITA enantiomers in healthy volunteers. In a cross-over study, healthy volunteers (n = 9) phenotyped as extensive metabolizers of CYP2C19 and CYP2D6 and with an oral midazolam clearance ranging from 10.9 to 149.3 ml min(-1) kg(-1) received a single dose of racemic CITA (20 mg orally) in combination or not with omeprazole (20 mg day(-1) for 18 days). Serial blood samples were collected up to 240 h after CITA administration. CITA and demethylcitalopram (DCITA) enantiomers were analyzed by LC-MS/MS using a Chiralcel OD-R column. The kinetic disposition of CITA was enantioselective in the absence of treatment with omeprazole, with the observation of a greater proportion of plasma (-)-(R)-CITA [AUC S:R ratio of 0.53 (95% CI 0.41, 0.66) for CITA and 1.08 (95% CI 0.80, 1.76) for DCITA] than (+)-(S)-CITA. Racemic CITA administration to healthy volunteers in combination with omeprazole showed a loss of enantioselectivity in CITA pharmacokinetics with an increase of approximately 120% in plasma (+)-(S)-CITA concentrations [AUC S:R ratio of 0.95 (95% CI 0.72, 1.10) for CITA and 0.95 (95% CI 0.44, 1.72) for DCITA]. The administration of multiple doses of omeprazole preferentially inhibited (+)-(S)-CITA metabolism in healthy volunteers. Although omeprazole increased plasma concentrations of (+)-(S)-CITA by approximately 120%, it is difficult to evaluate the clinical outcome because the range of plasma CITA concentrations related to maximum efficacy and minimum risk of adverse effects has not been

  19. Oncolytic reovirus preferentially induces apoptosis in KRAS mutant colorectal cancer cells, and synergizes with irinotecan

    PubMed Central

    Maitra, Radhashree; Seetharam, Raviraja; Tesfa, Lydia; Augustine, Titto A.; Klampfer, Lidija; Coffey, Matthew C.; Mariadason, John M.; Goel, Sanjay

    2014-01-01

    Reovirus is a double stranded RNA virus, with an intrinsic preference for replication in KRAS mutant cells. As 45% of human colorectal cancers (CRC) harbor KRAS mutations, we sought to investigate its efficacy in KRAS mutant CRC cells, and examine its impact in combination with the topoisimerase-1 inhibitor, irinotecan. Reovirus efficacy was examined in the KRAS mutant HCT116, and the isogenic KRAS WT Hke3 cell line, and in the non-malignant rat intestinal epithelial cell line. Apoptosis was determined by flow cytometry and TUNEL staining. Combination treatment with reovirus and irintoecan was investigated in 15 CRC cell lines, including the HCT116 p21 isogenic cell lines. Reovirus preferentially induced apoptosis in KRAS mutant HCT116 cells compared to its isogenic KRAS WT derivative, and in KRAS mutant IEC cells. Reovirus showed a greater degree of caspase 3 activation with PARP 1 cleavage, and preferential inhibition of p21 protein expression in KRAS mutant cells. Reovirus synergistically induced growth inhibition when combined with irinotecan. This synergy was lost upon p21 gene knock out. Reovirus preferentially induces apoptosis in KRAS mutant colon cancer cells. Reovirus and irinotecan combination therapy is synergistic, p21 mediated, and represents a novel potential treatment for patients with CRC. PMID:24798549

  20. H32, a non-quinone sulfone analog of vitamin K3, inhibits human hepatoma cell growth by inhibiting Cdc25 and activating ERK.

    PubMed

    Kar, Siddhartha; Wang, Meifang; Ham, Seung Wook; Carr, Brian I

    2006-10-01

    We previously synthesized a K-vitamin derivative, Cpd 5, which was a potent growth inhibitor of human tumor cells, including Hep3B hepatoma cells. However, being a quinone compound, Cpd 5 has the potential for generating toxic reactive oxygen species (ROS). We therefore synthesized a nonquinone sulfone derivative, H32, which has a sufone group substituting the quinone. The IC50 of H32 for Hep3B cells was found to be 2.5 microM, which was 2.5 and 3.2 times more potent than Cpd 5 and vitamin K3 respectively. It induced apoptosis in Hep3B cells but did not generate ROS when compared to Cpd 5. Interestingly, under similar culture conditions, normal rat hepatocytes were 14-fold more and 7-fold more resistant to the growth inhibitory effects of H32 than Hep3B and PLC/PRF5 cells respectively. H32 preferentially inhibited the activities of the cell cycle controlling Cdc25A phosphatase likely by binding to its catalytic cysteine. As a consequence, it induced inhibitory tyrosine phosphorylation of the Cdc25 substrate kinases Cdk2 and Cdk4 in Hep3B cells and the cells undergo an arrest in the G1 phase of the cell cycle. H32 also induced persistent phosphorylation of the MAPK protein ERK1/2, but marginal JNK1/2 and p38 phosphorylation. The ERK inhibitor U0126, added at least 30 min prior to H32, antagonized the growth inhibition induced by H32. However, the JNK and p38 inhibitors, JNKI-II and SB203580, were not able to antagonize H32 induced growth inhibition. Thus, H32 differentially inhibited growth of normal and liver tumor cells by preferentially inhibiting the actions of Cdc25 phosphatases and inducing persistent ERK phosphorylation.

  1. Are preferential flow paths perpetuated by microbial activity in the soil matrix? A review

    NASA Astrophysics Data System (ADS)

    Morales, Verónica L.; Parlange, J.-Yves; Steenhuis, Tammo S.

    2010-10-01

    SummaryRecently, the interactions between soil structure and microbes have been associated with water transport, retention and preferential or column flow development. Of particular significance is the potential impact of microbial extracellular polymeric substances (EPS) on soil porosity (i.e., hydraulic conductivity reduction or bioclogging) and of exudates from biota, including bacteria, fungi, roots and earthworms on the degree of soil water repellency. These structural and surface property changes create points of wetting instability, which under certain infiltrating conditions can often result in the formation of persistent preferential flow paths. Moreover, distinct differences in physical and chemical properties between regions of water flow (preferential flow paths) and no-flow (soil matrix) provide a unique set of environmental living conditions for adaptable microorganisms to exist. In this review, special consideration is given to: (1) the functional significance of microbial activity in the host porous medium in terms of feedback mechanisms instigated by irregular water availability and (2) the related physical and chemical conditions that force the organization and formation of unique microbial habitats in unsaturated soils that prompt and potentially perpetuate the formation of preferential flow paths in the vadose zone.

  2. α-Chymotrypsin in water-ethanol mixtures: Effect of preferential interactions

    NASA Astrophysics Data System (ADS)

    Sirotkin, Vladimir A.; Kuchierskaya, Alexandra A.

    2017-12-01

    We investigated preferential interactions of α-chymotrypsin with water-ethanol mixtures at 25 °C. Our approach is based on the analysis of residual enzyme activity and water/alcohol sorption. There are three concentration regimes. α-Chymotrypsin is preferentially hydrated at high water content. The residual enzyme activity is close to 100%. α-Chymotrypsin has a higher affinity for alcohol than for water at intermediate water content. Residual enzyme activity is close to zero in this concentration range. At low water content, ethanol is preferentially excluded from the protein surface. This results in preferential hydration of α-chymotrypsin and significant residual catalytic activity (∼50%) in water-poor ethanol.

  3. Modeling preferential water flow and solute transport in unsaturated soil using the active region model

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sheng, F.; Wang, K.; Zhang, R.

    2009-03-15

    Preferential flow and solute transport are common processes in the unsaturated soil, in which distributions of soil water content and solute concentrations are often characterized as fractal patterns. An active region model (ARM) was recently proposed to describe the preferential flow and transport patterns. In this study, ARM governing equations were derived to model the preferential soil water flow and solute transport processes. To evaluate the ARM equations, dye infiltration experiments were conducted, in which distributions of soil water content and Cl{sup -} concentration were measured. Predicted results using the ARM and the mobile-immobile region model (MIM) were compared withmore » the measured distributions of soil water content and Cl{sup -} concentration. Although both the ARM and the MIM are two-region models, they are fundamental different in terms of treatments of the flow region. The models were evaluated based on the modeling efficiency (ME). The MIM provided relatively poor prediction results of the preferential flow and transport with negative ME values or positive ME values less than 0.4. On the contrary, predicted distributions of soil water content and Cl- concentration using the ARM agreed reasonably well with the experimental data with ME values higher than 0.8. The results indicated that the ARM successfully captured the macroscopic behavior of preferential flow and solute transport in the unsaturated soil.« less

  4. Omeprazole preferentially inhibits the metabolism of (+)-(S)-citalopram in healthy volunteers

    PubMed Central

    Rocha, Adriana; Coelho, Eduardo B; Sampaio, Stefânia A; Lanchote, Vera L

    2010-01-01

    AIM The study assessed the influence of omeprazole on the kinetic disposition of the (+)-(S)-citalopram (CITA) and (−)-(R)-CITA enantiomers in healthy volunteers. METHODS In a cross-over study, healthy volunteers (n = 9) phenotyped as extensive metabolizers of CYP2C19 and CYP2D6 and with an oral midazolam clearance ranging from 10.9 to 149.3 ml min−1 kg−1 received a single dose of racemic CITA (20 mg orally) in combination or not with omeprazole (20 mg day−1 for 18 days). Serial blood samples were collected up to 240 h after CITA administration. CITA and demethylcitalopram (DCITA) enantiomers were analyzed by LC-MS/MS using a Chiralcel® OD-R column. RESULTS The kinetic disposition of CITA was enantioselective in the absence of treatment with omeprazole, with the observation of a greater proportion of plasma (−)-(R)-CITA [AUC S : R ratio of 0.53 (95% CI 0.41, 0.66) for CITA and 1.08 (95% CI 0.80, 1.76) for DCITA] than (+)-(S)-CITA. Racemic CITA administration to healthy volunteers in combination with omeprazole showed a loss of enantioselectivity in CITA pharmacokinetics with an increase of approximately 120% in plasma (+)-(S)-CITA concentrations [AUC S : R ratio of 0.95 (95% CI 0.72, 1.10) for CITA and 0.95 (95% CI 0.44, 1.72) for DCITA]. CONCLUSIONS The administration of multiple doses of omeprazole preferentially inhibited (+)-(S)-CITA metabolism in healthy volunteers. Although omeprazole increased plasma concentrations of (+)-(S)-CITA by approximately 120%, it is difficult to evaluate the clinical outcome because the range of plasma CITA concentrations related to maximum efficacy and minimum risk of adverse effects has not been established. PMID:20642546

  5. Potency and selectivity of carprofen enantiomers for inhibition of bovine cyclooxygenase in whole blood assays.

    PubMed

    Brentnall, Claire; Cheng, Zhangrui; McKellar, Quintin A; Lees, Peter

    2012-12-01

    Whole blood in vitro assays were used to determine the potency and selectivity of carprofen enantiomers for inhibition of the isoforms of cyclooxygenase (COX), COX-1 and COX-2, in the calf. S(+)-carprofen possessed preferential activity for COX-2 inhibition but, because the slopes of inhibition curves differed, the COX-1:COX-2 inhibition ratio decreased from 9.04:1 for inhibitory concentration (IC)10 to 1.84:1 for IC95. R(-) carprofen inhibited COX-2 preferentially only for low inhibition of the COX isoforms (IC10 COX-1:COX-2=6.63:1), whereas inhibition was preferential for COX-1 for a high level of inhibition (IC95 COX-1:COX-2=0.20:1). S(+) carprofen was the more potent inhibitor of COX isoforms; potency ratios S(+):R(-) carprofen were 11.6:1 for IC10 and 218:1 for IC90. Based on serum concentrations of carprofen enantiomers obtained after administration of a therapeutic dose of 1.4 mg/kg to calves subcutaneously, S(+)-carprofen concentrations exceeded the in vitro IC80 COX-2 value for 32 h and the IC20 for COX-1 for 33 h. The findings are discussed in relation to efficacy and safety of carprofen in calves. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. The cyclolignan PPP induces activation loop-specific inhibition of tyrosine phosphorylation of the insulin-like growth factor-1 receptor. Link to the phosphatidyl inositol-3 kinase/Akt apoptotic pathway.

    PubMed

    Vasilcanu, Daiana; Girnita, Ada; Girnita, Leonard; Vasilcanu, Radu; Axelson, Magnus; Larsson, Olle

    2004-10-14

    The insulin-like growth factor-1 receptor (IGF-1R) is crucial for many functions in neoplastic cells, for example, antiapoptosis. Recently, we demonstrated that the cyclolignan PPP efficiently inhibited phosphorylation of IGF-1R without interfering with insulin receptor activity. PPP preferentially reduced phosphorylated Akt, as compared to phosphorylated Erk1/2, and caused apoptosis. Now, we aimed to investigate how PPP inhibits the IGF-1R tyrosine kinase (IGF-1RTK) and the PI3K/Akt apoptotic pathway. Using a baculovirus driven IGF-1RTK we found that PPP interfered with tyrosine phosphorylation in the activation loop of the kinase domain. Specifically, it blocked phosphorylation of tyrosine (Y) 1136, while sparing the two others (Y1131 and Y1135). To explore the impact of inhibition of Y1136 on Akt phosphorylation we transfected P6 cells (overexpressing IGF-1R) and malignant melanoma cells with different IGF-1R mutants, including Y1136F (tyrosine replaced by phenylalanine). Y1136F was found to strongly decrease IGF-1 stimulated phosphorylation of Akt. Conversely, Akt phosphorylation was weakly affected in the Y1131F transfectant. Taken together, our data suggest that the preferential inhibition of phosphorylated Akt, after PPP treatment, may be due to specific inhibition of Y1136. PPP was proven not to interfere directly with Akt or any of its downstream molecules in the apoptotic pathway.

  7. Caffeine inhibition of GLUT1 is dependent on the activation state of the transporter.

    PubMed

    Gunnink, Leesha K; Busscher, Brianna M; Wodarek, Jeremy A; Rosette, Kylee A; Strohbehn, Lauren E; Looyenga, Brendan D; Louters, Larry L

    2017-06-01

    Caffeine has been shown to be a robust uncompetitive inhibitor of glucose uptake in erythrocytes. It preferentially binds to the nucleotide-binding site on GLUT1 in its tetrameric form and mimics the inhibitory action of ATP. Here we demonstrate that caffeine is also a dose-dependent, uncompetitive inhibitor of 2-deoxyglucose (2DG) uptake in L929 fibroblasts. The inhibitory effect on 2DG uptake in these cells was reversible with a rapid onset and was additive to the competitive inhibitory effects of glucose itself, confirming that caffeine does not interfere with glucose binding. We also report for the first time that caffeine inhibition was additive to inhibition by curcumin, suggesting distinct binding sites for curcumin and caffeine. In contrast, caffeine inhibition was not additive to that of cytochalasin B, consistent with previous data that reported that these two inhibitors have overlapping binding sites. More importantly, we show that the magnitude of maximal caffeine inhibition in L929 cells is much lower than in erythrocytes (35% compared to 90%). Two epithelial cell lines, HCLE and HK2, have both higher concentrations of GLUT1 and increased basal 2DG uptake (3-4 fold) compared to L929 cells, and subsequently display greater maximal inhibition by caffeine (66-70%). Interestingly, activation of 2DG uptake (3-fold) in L929 cells by glucose deprivation shifted the responsiveness of these cells to caffeine inhibition (35%-70%) without a change in total GLUT1 concentration. These data indicate that the inhibition of caffeine is dependent on the activity state of GLUT1, not merely on the concentration. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  8. Motility and Chemotaxis Mediate the Preferential Colonization of Gastric Injury Sites by Helicobacter pylori

    PubMed Central

    Aihara, Eitaro; Closson, Chet; Matthis, Andrea L.; Schumacher, Michael A.; Engevik, Amy C.; Zavros, Yana; Ottemann, Karen M.; Montrose, Marshall H.

    2014-01-01

    Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (106) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (106) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby biases

  9. Motility and chemotaxis mediate the preferential colonization of gastric injury sites by Helicobacter pylori.

    PubMed

    Aihara, Eitaro; Closson, Chet; Matthis, Andrea L; Schumacher, Michael A; Engevik, Amy C; Zavros, Yana; Ottemann, Karen M; Montrose, Marshall H

    2014-07-01

    Helicobacter pylori (H. pylori) is a pathogen contributing to peptic inflammation, ulceration, and cancer. A crucial step in the pathogenic sequence is when the bacterium first interacts with gastric tissue, an event that is poorly understood in vivo. We have shown that the luminal space adjacent to gastric epithelial damage is a microenvironment, and we hypothesized that this microenvironment might enhance H. pylori colonization. Inoculation with 106 H. pylori (wild-type Sydney Strain 1, SS1) significantly delayed healing of acetic-acid induced ulcers at Day 1, 7 and 30 post-inoculation, and wild-type SS1 preferentially colonized the ulcerated area compared to uninjured gastric tissue in the same animal at all time points. Gastric resident Lactobacillus spp. did not preferentially colonize ulcerated tissue. To determine whether bacterial motility and chemotaxis are important to ulcer healing and colonization, we analyzed isogenic H. pylori mutants defective in motility (ΔmotB) or chemotaxis (ΔcheY). ΔmotB (10(6)) failed to colonize ulcerated or healthy stomach tissue. ΔcheY (10(6)) colonized both tissues, but without preferential colonization of ulcerated tissue. However, ΔcheY did modestly delay ulcer healing, suggesting that chemotaxis is not required for this process. We used two-photon microscopy to induce microscopic epithelial lesions in vivo, and evaluated accumulation of fluorescently labeled H. pylori at gastric damage sites in the time frame of minutes instead of days. By 5 min after inducing damage, H. pylori SS1 preferentially accumulated at the site of damage and inhibited gastric epithelial restitution. H. pylori ΔcheY modestly accumulated at the gastric surface and inhibited restitution, but did not preferentially accumulate at the injury site. H. pylori ΔmotB neither accumulated at the surface nor inhibited restitution. We conclude that bacterial chemosensing and motility rapidly promote H. pylori colonization of injury sites, and thereby

  10. Shigella IpaH0722 E3 Ubiquitin Ligase Effector Targets TRAF2 to Inhibit PKC–NF-κB Activity in Invaded Epithelial Cells

    PubMed Central

    Ashida, Hiroshi; Nakano, Hiroyasu; Sasakawa, Chihiro

    2013-01-01

    NF-κB plays a central role in modulating innate immune responses to bacterial infections. Therefore, many bacterial pathogens deploy multiple mechanisms to counteract NF-κB activation. The invasion of and subsequent replication of Shigella within epithelial cells is recognized by various pathogen recognition receptors as pathogen-associated molecular patterns. These receptors trigger innate defense mechanisms via the activation of the NF-κB signaling pathway. Here, we show the inhibition of the NF-κB activation by the delivery of the IpaH E3 ubiquitin ligase family member IpaH0722 using Shigella's type III secretion system. IpaH0722 dampens the acute inflammatory response by preferentially inhibiting the PKC-mediated activation of NF-κB by ubiquitinating TRAF2, a molecule downstream of PKC, and by promoting its proteasome-dependent degradation. PMID:23754945

  11. Selective Inhibition of Tumor Oncogenes by Disruption of Super-Enhancers

    PubMed Central

    Lovén, Jakob; Hoke, Heather A.; Lin, Charles Y.; Lau, Ashley; Orlando, David A.; Vakoc, Christopher R.; Bradner, James E.; Lee, Tong Ihn; Young, Richard A.

    2013-01-01

    Summary Chromatin regulators have become attractive targets for cancer therapy, but it is unclear why inhibition of these ubiquitous regulators should have gene-specific effects in tumor cells. Here, we investigate how inhibition of the widely expressed transcriptional coactivator BRD4 leads to selective inhibition of the MYC oncogene in multiple myeloma (MM). BRD4 and Mediator were found to co-occupy thousands of enhancers associated with active genes. They also co-occupied a small set of exceptionally large super-enhancers associated with genes that feature prominently in MM biology, including the MYC oncogene. Treatment of MM tumor cells with the BET-bromodomain inhibitor JQ1 led to preferential loss of BRD4 at super-enhancers and consequent transcription elongation defects that preferentially impacted genes with super-enhancers, including MYC. Super-enhancers were found at key oncogenic drivers in many other tumor cells. These observations have implications for the discovery of cancer therapeutics directed at components of super-enhancers in diverse tumor types. PMID:23582323

  12. Mechanism of lignin inhibition of enzymatic biomass deconstruction

    DOE PAGES

    Vermaas, Josh V.; Petridis, Loukas; Qi, Xianghong; ...

    2015-12-01

    The conversion of plant biomass to ethanol via enzymatic cellulose hydrolysis offers a potentially sustainable route to biofuel production. However, the inhibition of enzymatic activity in pretreated biomass by lignin severely limits the efficiency of this process. By performing atomic-detail molecular dynamics simulation of a biomass model containing cellulose, lignin, and cellulases (TrCel7A), we elucidate detailed lignin inhibition mechanisms. We find that lignin binds preferentially both to the elements of cellulose to which the cellulases also preferentially bind (the hydrophobic faces) and also to the specific residues on the cellulose-binding module of the cellulase that are critical for cellulose bindingmore » of TrCel7A (Y466, Y492, and Y493). In conclusion, lignin thus binds exactly where for industrial purposes it is least desired, providing a simple explanation of why hydrolysis yields increase with lignin removal.« less

  13. Preferential inhibition of Ih in rat trigeminal ganglion neurons by an organic blocker.

    PubMed

    Janigro, D; Martenson, M E; Baumann, T K

    1997-11-15

    The potency and specificity of a novel organic Ih current blocker DK-AH 268 (DK, Boehringer) was studied in cultured rat trigeminal ganglion neurons using whole-cell patch-clamp recording techniques. In neurons current-clamped at the resting potential, the application of 10 microM DK caused a slight hyperpolarization of the membrane potential and a small increase in the threshold for action potential discharge without any major change in the shape of the action potential. In voltage-clamped neurons, DK caused a reduction of a hyperpolarization-activated current. Current subtraction protocols revealed that the time-dependent, hyperpolarization-activated currents blocked by 10 microM DK or external Cs+ (3 mM) had virtually identical activation properties, suggesting that DK and Cs+ caused blockade of the same current, namely Ih. The block of Ih by DK was dose-dependent. At the intermediate and higher concentrations of DK (10 and 100 microM) a decrease in specificity was observed so that time-independent, inwardly rectifying and noninactivating, voltage-gated outward potassium currents were also reduced by DK but to a much lesser extent than the time-dependent, hyperpolarization-activated currents. Blockade of the time-dependent, hyperpolarization-activated currents by DK appeared to be use-dependent since it required hyperpolarization for the effect to take place. Relief of DK block was also aided by membrane hyperpolarization. Since both the time-dependent current blocked by DK and the Cs+-sensitive time-dependent current behaved as Ih, we conclude that 10 microM DK can preferentially reduce Ih without a major effect on other potassium currents. Thus, DK may be a useful agent in the investigation of the function of Ih in neurons.

  14. Active and Passive Radiative Transfer Modeling with Preferentially-Aligned Particles

    NASA Technical Reports Server (NTRS)

    Adams, Ian Stuart

    2017-01-01

    The fluid dynamics of falling hydrometeors often results in preferential orientations that can affect both the intensity and polarization of electromagnetic radiation. In order to properly interpret remote sensing observations of ice and snow, such alignments should be considered when constructing databases of scattering particles; however, the inclusion of aligned particles increases the complexity of the scattering data. To demonstrate the use of scattering properties of preferentially-aligned particles, millimeter-wave brightness temperatures and radar observables, including reflectivity and linear depolarization ratio, are modeled using the Atmospheric Radiative Transfer Simulator (ARTS). The necessary scattering parameters for vector radiative transfer, particularly with respect to ARTS, are reviewed, and the exploitation of particle symmetries, as well as scattering reciprocity relationships, are detailed.

  15. Temporal evolution of water repellency and preferential flow in the post-fire

    NASA Astrophysics Data System (ADS)

    Alanís, Nancy; Jordán, Antonio; Zavala, Lorena M.

    2015-04-01

    Forest fires usually intensify erosive process due to the reduction of vegetation cover and degradation of aggregation in the topsoil. Another common effect of wildifres is the development of soil water repellency, which in turn favors the formation of runoff, inhibiting or delaying infiltration. Under these conditions, infiltration occurs only when ponded water or runoff flow finds macropores and cracks in the soil surface, producing preferential flow pathways. When water infiltrates through these paths, a significant portion of the soil remains dry, limiting the supply of nutrients to the roots, favoring the rapid leaching of nutrients and agrochemicals, and other impacts on flora and hydrological processes at hillslope- or basin-scale. The existence of irregular wetting fronts has been observed frequently in burned or unburned water repellent soils. Although some authors have suggested that preferential flow paths may be more or less permanent in the case of unburned soils, the temporal evolution of preferential flow has been rarely studied in burned soils during the post-fire, after water repellency decreases or disappears. This research focuses on the temporal evolution of water repellency and preferential flows in an area affected by fire.

  16. Activation of dopamine D3 receptors inhibits reward-related learning induced by cocaine.

    PubMed

    Kong, H; Kuang, W; Li, S; Xu, M

    2011-03-10

    Memories of learned associations between the rewarding properties of drugs and environmental cues contribute to craving and relapse in humans. The mesocorticolimbic dopamine (DA) system is involved in reward-related learning induced by drugs of abuse. DA D3 receptors are preferentially expressed in mesocorticolimbic DA projection areas. Genetic and pharmacological studies have shown that DA D3 receptors suppress locomotor-stimulant effects of cocaine and reinstatement of cocaine-seeking behaviors. Activation of the extracellular signal-regulated kinase (ERK) induced by acute cocaine administration is also inhibited by D3 receptors. How D3 receptors modulate cocaine-induced reward-related learning and associated changes in cell signaling in reward circuits in the brain, however, have not been fully investigated. In the present study, we show that D3 receptor mutant mice exhibit potentiated acquisition of conditioned place preference (CPP) at low doses of cocaine compared to wild-type mice. Activation of ERK and CaMKIIα, but not the c-Jun N-terminal kinase and p38, in the nucleus accumbens, amygdala and prefrontal cortex is also potentiated in D3 receptor mutant mice compared to that in wild-type mice following CPP expression. These results support a model in which D3 receptors modulate reward-related learning induced by low doses of cocaine by inhibiting activation of ERK and CaMKIIα in reward circuits in the brain. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  17. Integration between Glycolysis and Glutamate-Glutamine Cycle Flux May Explain Preferential Glycolytic Increase during Brain Activation, Requiring Glutamate

    PubMed Central

    Hertz, Leif; Chen, Ye

    2017-01-01

    The 1988 observation by Fox et al. (1988) that brief intense brain activation increases glycolysis (pyruvate formation from glucose) much more than oxidative metabolism has been abundantly confirmed. Specifically glycolytic increase was unexpected because the amount of ATP it generates is much smaller than that formed by subsequent oxidative metabolism of pyruvate. The present article shows that preferential glycolysis can be explained by metabolic processes associated with activation of the glutamate-glutamine cycle. The flux in this cycle, which is essential for production of transmitter glutamate and GABA, equals 75% of brain glucose utilization and each turn is associated with utilization of ~1 glucose molecule. About one half of the association between cycle flux and glucose metabolism occurs during neuronal conversion of glutamine to glutamate in a process similar to the malate-aspartate shuttle (MAS) except that glutamate is supplied from glutamine, not formed from α-ketoglutarate (αKG) as during operation of conventional MAS. Regular MAS function is triggered by one oxidative process in the cytosol during glycolysis causing NAD+ reduction to NADH. Since NADH cannot cross the mitochondrial membrane (MEM) for oxidation NAD+ is re-generated by conversion of cytosolic oxaloacetate (OAA) to malate, which enters the mitochondria for oxidation and in a cyclic process regenerates cytosolic OAA. Therefore MAS as well as the “pseudo-MAS” necessary for neuronal glutamate formation can only operate together with cytosolic reduction of NAD+ to NADH. The major process causing NAD+ reduction is glycolysis which therefore also must occur during neuronal conversion of glutamine to glutamate and may energize vesicular glutamate uptake which preferentially uses glycolytically derived energy. Another major contributor to the association between glutamate-glutamine cycle and glucose utilization is the need for astrocytic pyruvate to generate glutamate. Although some

  18. Salicylic acid metabolites and derivatives inhibit CDK activity: Novel insights into aspirin's chemopreventive effects against colorectal cancer

    PubMed Central

    Dachineni, Rakesh; Kumar, D. Ramesh; Callegari, Eduardo; Kesharwani, Siddharth S.; Sankaranarayanan, Ranjini; Seefeldt, Teresa; Tummala, Hemachand; Bhat, G. Jayarama

    2017-01-01

    Aspirin's potential as a drug continues to be evaluated for the prevention of colorectal cancer (CRC). Although multiple targets for aspirin and its metabolite, salicylic acid, have been identified, no unifying mechanism has been proposed to clearly explain its chemopreventive effects. Our goal here was to investigate the ability of salicylic acid metabolites, known to be generated through cytochrome P450 (CYP450) enzymes, and its derivatives as cyclin dependent kinase (CDK) inhibitors to gain new insights into aspirin's chemopreventive actions. Using in vitro kinase assays, for the first time, we demonstrate that salicylic acid metabolites, 2,3-dihydroxy-benzoic acid (2,3-DHBA) and 2,5-dihydroxybenzoic acid (2,5-DHBA), as well as derivatives 2,4-dihydroxybenzoic acid (2,4-DHBA), 2,6-dihydroxybenzoic acid (2,6-DHBA), inhibited CDK1 enzyme activity. 2,3-DHBA and 2,6-DHBA did not inhibit CDK2 and 4; however, both inhibited CDK-6 activity. Interestingly, another derivative, 2,4,6-trihydroxybenzoic acid (2,4,6-THBA) was highly effective in inhibiting CDK1, 2, 4 and 6 activity. Molecular docking studies showed that these compounds potentially interact with CDK1. Immunoblotting experiments showed that aspirin acetylated CDK1, and pre-incubation with salicylic acid and its derivatives prevented aspirin-mediated CDK1 acetylation, which supported the data obtained from molecular docking studies. We suggest that intracellularly generated salicylic acid metabolites through CYP450 enzymes within the colonic epithelial cells, or the salicylic acid metabolites generated by gut microflora may significantly contribute to the preferential chemopreventive effect of aspirin against CRC through inhibition of CDKs. This novel hypothesis and mechanism of action in aspirin's chemopreventive effects opens a new area for future research. In addition, structural modification to salicylic acid derivatives may prove useful in the development of novel CDK inhibitors in cancer prevention and

  19. N-acetylcysteine inhibits endothelial cell invasion and angiogenesis.

    PubMed

    Cai, T; Fassina, G; Morini, M; Aluigi, M G; Masiello, L; Fontanini, G; D'Agostini, F; De Flora, S; Noonan, D M; Albini, A

    1999-09-01

    The thiol N-acetylcysteine (NAC) is a chemopreventive agent that acts through a variety of mechanisms and can prevent in vivo carcinogenesis. We have previously shown that NAC inhibits invasion and metastasis of malignant cells as well as tumor take. Neovascularization is critical for tumor mass expansion and metastasis formation. We investigated whether a target of the anti-cancer activity of NAC could be the inhibition of the tumor angiogenesis-associated phenotype in vitro and in vivo using the potent angiogenic mixture of Kaposi's sarcoma cell products as a stimulus. Two endothelial (EAhy926 and human umbilical vein endothelial [HUVE]) cell lines were utilized in a panel of assays to test NAC ability in inhibiting chemotaxis, invasion, and gelatinolytic activity in vitro. NAC treatment of EAhy926 and HUVE cells in vitro dose-dependently reduced their ability to invade a reconstituted basement membrane, an indicator of endothelial cell activation. Invasion of HUVE cells was inhibited with an ID50 of 0.24 mM NAC, whereas inhibition of chemotaxis required a 10 fold higher doses, indicating that invasion is a preferential target. NAC inhibited the enzymatic activity and conversion to active forms of the gelatinase produced by endothelial cells. The matrigel in vivo assay was used for the evaluation of angiogenesis; NAC strongly inhibited neovascularization of the matrigel sponges in response to Kaposi's sarcoma cell products. NAC prevented angiogenesis while preserving endothelial cells, implying that it could be safely used as an anti-angiogenic treatment.

  20. Hydrogen peroxide preferentially activates capsaicin-sensitive high threshold afferents via TRPA1 channels in the guinea pig bladder.

    PubMed

    Nicholas, S; Yuan, S Y; Brookes, S J H; Spencer, N J; Zagorodnyuk, V P

    2017-01-01

    There is increasing evidence suggesting that ROS play a major pathological role in bladder dysfunction induced by bladder inflammation and/or obstruction. The aim of this study was to determine the effect of H 2 O 2 on different types of bladder afferents and its mechanism of action on sensory neurons in the guinea pig bladder. 'Close-to-target' single unit extracellular recordings were made from fine branches of pelvic nerves entering the guinea pig bladder, in flat sheet preparations, in vitro. H 2 O 2 (300-1000 μM) preferentially and potently activated capsaicin-sensitive high threshold afferents but not low threshold stretch-sensitive afferents, which were only activated by significantly higher concentrations of hydrogen peroxide. The TRPV1 channel agonist, capsaicin, excited 86% of high threshold afferents. The TRPA1 channel agonist, allyl isothiocyanate and the TRPM8 channel agonist, icilin activated 72% and 47% of capsaicin-sensitive high threshold afferents respectively. The TRPA1 channel antagonist, HC-030031, but not the TRPV1 channel antagonist, capsazepine or the TRPM8 channel antagonist, N-(2-aminoethyl)-N-[[3-methoxy-4-(phenylmethoxy)phenyl]methyl]thiophene-2-carboxamide, significantly inhibited the H 2 O 2 -induced activation of high threshold afferents. Dimethylthiourea and deferoxamine did not significantly change the effect of H 2 O 2 on high threshold afferents. The findings show that H 2 O 2 , in the concentration range detected in inflammation or reperfusion after ischaemia, evoked long-lasting activation of the majority of capsaicin-sensitive high threshold afferents, but not low threshold stretch-sensitive afferents. The data suggest that the TRPA1 channels located on these capsaicin-sensitive afferent fibres are probable targets of ROS released during oxidative stress. © 2016 The British Pharmacological Society.

  1. Hydrogen peroxide preferentially activates capsaicin‐sensitive high threshold afferents via TRPA1 channels in the guinea pig bladder

    PubMed Central

    Nicholas, S; Yuan, S Y; Brookes, S J H; Spencer, N J

    2016-01-01

    Background and Purpose There is increasing evidence suggesting that ROS play a major pathological role in bladder dysfunction induced by bladder inflammation and/or obstruction. The aim of this study was to determine the effect of H2O2 on different types of bladder afferents and its mechanism of action on sensory neurons in the guinea pig bladder. Experimental Approach ‘Close‐to‐target’ single unit extracellular recordings were made from fine branches of pelvic nerves entering the guinea pig bladder, in flat sheet preparations, in vitro. Key Results H2O2 (300–1000 μM) preferentially and potently activated capsaicin‐sensitive high threshold afferents but not low threshold stretch‐sensitive afferents, which were only activated by significantly higher concentrations of hydrogen peroxide. The TRPV1 channel agonist, capsaicin, excited 86% of high threshold afferents. The TRPA1 channel agonist, allyl isothiocyanate and the TRPM8 channel agonist, icilin activated 72% and 47% of capsaicin‐sensitive high threshold afferents respectively. The TRPA1 channel antagonist, HC‐030031, but not the TRPV1 channel antagonist, capsazepine or the TRPM8 channel antagonist, N‐(2‐aminoethyl)‐N‐[[3‐methoxy‐4‐(phenylmethoxy)phenyl]methyl]thiophene‐2‐carboxamide, significantly inhibited the H2O2‐induced activation of high threshold afferents. Dimethylthiourea and deferoxamine did not significantly change the effect of H2O2 on high threshold afferents. Conclusions and Implications The findings show that H2O2, in the concentration range detected in inflammation or reperfusion after ischaemia, evoked long‐lasting activation of the majority of capsaicin‐sensitive high threshold afferents, but not low threshold stretch‐sensitive afferents. The data suggest that the TRPA1 channels located on these capsaicin‐sensitive afferent fibres are probable targets of ROS released during oxidative stress. PMID:27792844

  2. Neuroglobin Overexpression Inhibits AMPK Signaling and Promotes Cell Anabolism.

    PubMed

    Cai, Bin; Li, Wenjun; Mao, XiaoOu; Winters, Ali; Ryou, Myoung-Gwi; Liu, Ran; Greenberg, David A; Wang, Ning; Jin, Kunlin; Yang, Shao-Hua

    2016-03-01

    Neuroglobin (Ngb) is a recently discovered globin with preferential localization to neurons. Growing evidence indicates that Ngb has distinct physiological functions separate from the oxygen storage and transport roles of other globins, such as hemoglobin and myoglobin. We found increased ATP production and decreased glycolysis in Ngb-overexpressing immortalized murine hippocampal cell line (HT-22), in parallel with inhibition of AMP-activated protein kinase (AMPK) signaling and activation of acetyl-CoA carboxylase (ACC). In addition, lipid and glycogen content was increased in Ngb-overexpressing HT-22 cells. AMPK signaling was also inhibited in the brain and heart from Ngb-overexpressing transgenic mice. Although Ngb overexpression did not change glycogen content in whole brain, glycogen synthase was activated in cortical neurons of Ngb-overexpressing mouse brain and Ngb overexpression primary neurons. Moreover, lipid and glycogen content was increased in hearts derived from Ngb-overexpressing mice. These findings suggest that Ngb functions as a metabolic regulator and enhances cellular anabolism through the inhibition of AMPK signaling.

  3. Silibinin preferentially radiosensitizes prostate cancer by inhibiting DNA repair signaling

    PubMed Central

    Nambiar, Dhanya K.; Rajamani, Paulraj; Deep, Gagan; Jain, Anil K.; Agarwal, Rajesh; Singh, Rana P.

    2015-01-01

    Radiotherapy, a frequent mode of cancer treatment, is often restricted by dose-related toxicity and development of therapeutic resistance. To develop a novel and selective radiosensitizer, we studied the radiosensitizing effects and associated mechanisms of silibinin in prostate cancer (PCa). The radiosensitizing effect of silibinin with ionizing radiation (IR) was assessed on radioresistant PCa cell lines by clonogenic, cell cycle, cell death and DNA repair assays. Tumor xenograft growth, immunohistochemical (IHC) analysis of tumor tissues, and toxicity-related parameters were measured in vivo. Silibinin (25 μM) enhanced IR (2.5-10 Gy)-caused inhibition (up to 96%, P<0.001) of colony formation selectively in PCa cells, and prolonged and enhanced IR-caused G2/M arrest, apoptosis and ROS production. Mechanistically, silibinin inhibited IR-induced DNA repair (ATM and Chk1/2) and EGFR signaling and attenuated the levels of anti-apoptotic proteins. Specifically, silibinin suppressed IR-induced nuclear translocation of EGFR and DNA-PK, an important mediator of DSB repair, leading to an increased number of γ-H2AX (ser139) foci suggesting lesser DNA repair. In vivo, silibinin strongly radiosensitized DU145 tumor xenograft inhibition (84%, P<0.01) with higher apoptotic response (10-fold, P<0.01) and reduced repair of DNA damage, and rescued the mice from IR-induced toxicity and hematopoietic injury. Overall, silibinin enhanced the radiotherapeutic response via suppressing IR-induced pro-survival signaling and DSB repair by inhibiting nuclear translocation of EGFR and DNA-PK. Since silibinin is already in phase II clinical trial for PCa patients, the present finding has translational relevance for radioresistant PCa. PMID:26516160

  4. Silibinin Preferentially Radiosensitizes Prostate Cancer by Inhibiting DNA Repair Signaling.

    PubMed

    Nambiar, Dhanya K; Rajamani, Paulraj; Deep, Gagan; Jain, Anil K; Agarwal, Rajesh; Singh, Rana P

    2015-12-01

    Radiotherapy, a frequent mode of cancer treatment, is often restricted by dose-related toxicity and development of therapeutic resistance. To develop a novel and selective radiosensitizer, we studied the radiosensitizing effects and associated mechanisms of silibinin in prostate cancer. The radiosensitizing effect of silibinin with ionizing radiation (IR) was assessed on radioresistant prostate cancer cell lines by clonogenic, cell cycle, cell death, and DNA repair assays. Tumor xenograft growth, immunohistochemical (IHC) analysis of tumor tissues, and toxicity-related parameters were measured in vivo. Silibinin (25 μmol/L) enhanced IR (2.5-10 Gy)-caused inhibition (up to 96%, P < 0.001) of colony formation selectively in prostate cancer cells, and prolonged and enhanced IR-caused G2-M arrest, apoptosis, and ROS production. Mechanistically, silibinin inhibited IR-induced DNA repair (ATM and Chk1/2) and EGFR signaling and attenuated the levels of antiapoptotic proteins. Specifically, silibinin suppressed IR-induced nuclear translocation of EGFR and DNA-PK, an important mediator of DSB repair, leading to an increased number of γ-H2AX (ser139) foci suggesting lesser DNA repair. In vivo, silibinin strongly radiosensitized DU145 tumor xenograft inhibition (84%, P < 0.01) with higher apoptotic response (10-fold, P < 0.01) and reduced repair of DNA damage, and rescued the mice from IR-induced toxicity and hematopoietic injury. Overall, silibinin enhanced the radiotherapeutic response via suppressing IR-induced prosurvival signaling and DSB repair by inhibiting nuclear translocation of EGFR and DNA-PK. Because silibinin is already in phase II clinical trial for prostate cancer patients, the present finding has translational relevance for radioresistant prostate cancer. ©2015 American Association for Cancer Research.

  5. Preferential nucleation during polymorphic transformations

    DOE PAGES

    Sharma, H.; Sietsma, J.; Offerman, S. E.

    2016-08-03

    Polymorphism is the ability of a solid material to exist in more than one phase or crystal structure. Polymorphism may occur in metals, alloys, ceramics, minerals, polymers, and pharmaceutical substances. Unresolved are the conditions for preferential nucleation during polymorphic transformations in which structural relationships or special crystallographic orientation relationships (OR’s) form between the nucleus and surrounding matrix grains. We measured in-situ and simultaneously the nucleation rates of grains that have zero, one, two, three and four special OR’s with the surrounding parent grains. These experiments show a trend in which the activation energy for nucleation becomes smaller – and thereforemore » nucleation more probable - with increasing number of special OR’s. As a result, these insights contribute to steering the processing of polymorphic materials with tailored properties, since preferential nucleation affects which crystal structure forms, the average grain size and texture of the material, and thereby - to a large extent - the final properties of the material.« less

  6. Nonsteroidal anti-inflammatory drugs inhibit gastric peroxidase activity.

    PubMed

    Banerjee, R K

    1990-06-20

    The peroxidase activity of the mitochondrial fraction of rat gastric mucosa was inhibited with various nonsteroidal anti-inflammatory drugs (NSAIDs) in vitro. Indomethacin was found to be more effective than phenylbutazone (PB) or acetylsalicylic acid (ASA). Mouse gastric peroxidase was also very sensitive to indomethacin inhibition. Indomethacin has no significant effect on submaxillary gland peroxidase activity of either of the species studied. Purified rat gastric peroxidase activity was inhibited 75% with 0.15 mM indomethacin showing half-maximal inhibition at 0.04 mM. The inhibition could be withdrawn by increasing the concentration of iodide but not by H2O2. NSAIDs inhibit gastric peroxidase activity more effectively at acid pH (pH 5.2) than at neutral pH. Spectral studies showed a bathochromic shift of the Soret band of the enzyme with indomethacin indicating its interaction at or near the heme part of the enzyme.

  7. α-chymotrypsin in water-acetone and water-dimethyl sulfoxide mixtures: Effect of preferential solvation and hydration.

    PubMed

    Sirotkin, Vladimir A; Kuchierskaya, Alexandra A

    2017-10-01

    We investigated water/organic solvent sorption and residual enzyme activity to simultaneously monitor preferential solvation/hydration of protein macromolecules in the entire range of water content at 25°C. We applied this approach to estimate protein destabilization/stabilization due to the preferential interactions of bovine pancreatic α-chymotrypsin with water-acetone (moderate-strength H-bond acceptor) and water-DMSO (strong H-bond acceptor) mixtures. There are three concentration regimes for the dried α-chymotrypsin. α-Chymotrypsin is preferentially hydrated at high water content. The residual enzyme activity values are close to 100%. At intermediate water content, the dehydrated α-chymotrypsin has a higher affinity for acetone/DMSO than for water. Residual enzyme activity is minimal in this concentration range. The acetone/DMSO molecules are preferentially excluded from the protein surface at the lowest water content, resulting in preferential hydration. The residual catalytic activity in the water-poor acetone is ∼80%, compared with that observed after incubation in pure water. This effect is very small for the water-poor DMSO. Two different schemes are operative for the hydrated enzyme. At high and intermediate water content, α-chymotrypsin exhibits preferential hydration. However, at intermediate water content, in contrast to the dried enzyme, the initially hydrated α-chymotrypsin possesses increased preferential hydration parameters. At low water content, no residual enzyme activity was observed. Preferential binding of DMSO/acetone to α-chymotrypsin was detected. Our data clearly demonstrate that the hydrogen bond accepting ability of organic solvents and the protein hydration level constitute key factors in determining the stability of protein-water-organic solvent systems. © 2017 Wiley Periodicals, Inc.

  8. Preferential adsorption of fluorescing fulvic and humic acid components on activated carbon using flow field-flow fractionation analysis.

    PubMed

    Schmit, Kathryn H; Wells, Martha J M

    2002-02-01

    Activated carbon treatment of drinking water is used to remove natural organic matter (NOM) precursors that lead to the formation of disinfection byproducts. The innate hydrophobic nature and macromolecular size of NOM render it amenable to sorption by activated carbon. Batch equilibrium and minicolumn breakthrough adsorption studies were performed using granular activated carbon to treat NOM-contaminated water. Ultraviolet (UV) absorption spectroscopy and flow field-flow fractionation analysis using tandem diode-array and fluorescence detectors were used to monitor the activated carbon sorption of NOM. Using these techniques, it was possible to study activated carbon adsorption properties of UV absorbing, fluorescing and nonfluorescing, polyelectrolytic macromolecules fractionated from the total macromolecular and nonmacromolecular composition of NOM. Adsorption isotherms were constructed at pH 6 and pH 9. Data were described by the traditional and modified Freundlich models. Activated carbon capacity and adsorbability were compared among fractionated molecular subsets of fulvic and humic acids. Preferential adsorption (or adsorptive fractionation) of polyelectrolytic, fluorescing fulvic and humic macromolecules on activated carbon was observed. The significance of observing preferential adsorption on activated carbon of fluorescing macromolecular components relative to nonfluorescing components is that this phenomenon changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the composition that existed in the aqueous phase prior to adsorption. Likewise, it changes the composition of dissolved organic matter remaining in equilibrium in the aqueous phase relative to the adsorbed phase. This research increases our understanding of NOM interactions with activated carbon which may lead to improved methods of potable water production.

  9. Pulsed Out of Awareness: EEG Alpha Oscillations Represent a Pulsed-Inhibition of Ongoing Cortical Processing

    PubMed Central

    Mathewson, Kyle E.; Lleras, Alejandro; Beck, Diane M.; Fabiani, Monica; Ro, Tony; Gratton, Gabriele

    2011-01-01

    Alpha oscillations are ubiquitous in the brain, but their role in cortical processing remains a matter of debate. Recently, evidence has begun to accumulate in support of a role for alpha oscillations in attention selection and control. Here we first review evidence that 8–12 Hz oscillations in the brain have a general inhibitory role in cognitive processing, with an emphasis on their role in visual processing. Then, we summarize the evidence in support of our recent proposal that alpha represents a pulsed-inhibition of ongoing neural activity. The phase of the ongoing electroencephalography can influence evoked activity and subsequent processing, and we propose that alpha exerts its inhibitory role through alternating microstates of inhibition and excitation. Finally, we discuss evidence that this pulsed-inhibition can be entrained to rhythmic stimuli in the environment, such that preferential processing occurs for stimuli at predictable moments. The entrainment of preferential phase may provide a mechanism for temporal attention in the brain. This pulsed inhibitory account of alpha has important implications for many common cognitive phenomena, such as the attentional blink, and seems to indicate that our visual experience may at least some times be coming through in waves. PMID:21779257

  10. Infective Juveniles of the Entomopathogenic Nematode Steinernema scapterisci Are Preferentially Activated by Cricket Tissue

    PubMed Central

    2017-01-01

    Entomopathogenic nematodes are a subgroup of insect-parasitic nematodes that are used in biological control as alternatives or supplements to chemical pesticides. Steinernema scapterisci is an unusual member of the entomopathogenic nematode guild for many reasons including that it is promiscuous in its association with bacteria, it can reproduce in the absence of its described bacterial symbiont, and it is known to have a narrow host range. It is a powerful comparative model within the species and could be used to elucidate parasite specialization. Here we describe a new method of efficiently producing large numbers of S. scapterisci infective juveniles (IJs) in house crickets and for quantifying parasitic activation of the IJs upon exposure to host tissue using morphological features. We found that parasite activation is a temporal process with more IJs activating over time. Furthermore, we found that activated IJs secrete a complex mixture of proteins and that S. scapterisci IJs preferentially activate upon exposure to cricket tissue, reaffirming the description of S. scapterisci as a cricket specialist. PMID:28046065

  11. Infective Juveniles of the Entomopathogenic Nematode Steinernema scapterisci Are Preferentially Activated by Cricket Tissue.

    PubMed

    Lu, Dihong; Sepulveda, Claudia; Dillman, Adler R

    2017-01-01

    Entomopathogenic nematodes are a subgroup of insect-parasitic nematodes that are used in biological control as alternatives or supplements to chemical pesticides. Steinernema scapterisci is an unusual member of the entomopathogenic nematode guild for many reasons including that it is promiscuous in its association with bacteria, it can reproduce in the absence of its described bacterial symbiont, and it is known to have a narrow host range. It is a powerful comparative model within the species and could be used to elucidate parasite specialization. Here we describe a new method of efficiently producing large numbers of S. scapterisci infective juveniles (IJs) in house crickets and for quantifying parasitic activation of the IJs upon exposure to host tissue using morphological features. We found that parasite activation is a temporal process with more IJs activating over time. Furthermore, we found that activated IJs secrete a complex mixture of proteins and that S. scapterisci IJs preferentially activate upon exposure to cricket tissue, reaffirming the description of S. scapterisci as a cricket specialist.

  12. Neuroglobin Overexpression Inhibits AMPK Signaling and Promotes Cell Anabolism

    PubMed Central

    Cai, Bin; Li, Wenjun; Mao, XiaoOu; Winters, Ali; Ryou, Myoung-Gwi; Liu, Ran; Greenberg, David A.; Wang, Ning; Jin, Kunlin; Yang, Shao-Hua

    2017-01-01

    Neuroglobin (Ngb) is a recently discovered globin with preferential localization to neurons. Growing evidence indicates that Ngb has distinct physiological functions separate from the oxygen storage and transport roles of other globins, such as hemoglobin and myoglobin. We found increased ATP production and decreased glycolysis in Ngb-overexpressing immortalized murine hippocampal cell line (HT-22), in parallel with inhibition of AMPK signaling and activation of acetyl-CoA carboxylase (ACC). In addition, lipid and glycogen content was increased in Ngb-overexpressing HT-22 cells. AMPK signaling was also inhibited in brain and heart from Ngb-overexpressing transgenic mice. Although Ngb overexpression did not change glycogen content in whole brain, glycogen synthase was activated in cortical neurons of Ngb overexpressing mouse brain and Ngb overexpression primary neurons. Moreover, lipid and glycogen content was increased in hearts derived from Ngb-overexpressing mice. These findings suggest that Ngb functions as a metabolic regulator and enhances cellular anabolism through the inhibition of AMPK signaling. PMID:25616953

  13. Inhibition of PTEN and activation of Akt by menadione.

    PubMed

    Yoshikawa, Kyoko; Nigorikawa, Kiyomi; Tsukamoto, Mariko; Tamura, Namiko; Hazeki, Kaoru; Hazeki, Osamu

    2007-04-01

    Menadione (vitamin K(3)) has been shown to activate Erk in several cell lines. This effect has been shown to be due to the activation of EGF receptors (EGFR) as a result of inhibition of some protein tyrosine phosphatases. In the present study, we examined the effects of menadione on Akt in Chinese hamster ovary cells. The phosphorylation of Akt by menadione was not inhibited by AG1478, an inhibitor of EGFR. Menadione inhibited the lipid phosphatase activity of PTEN in a cell-free system. In an intact cell system, menadione inhibited the effect of transfected PTEN on Akt. Thus, one mechanism of its action was considered the accelerated activation of Akt through inhibition of PTEN. This was not the sole mechanism responsible for the EGFR-independent activation of Akt, because menadione attenuated the rate of Akt dephosphorylation even in PTEN-null PC3 cells. The decelerated inactivation of Akt, probably through inhibition of some tyrosine phosphatases, was considered another mechanism of its action.

  14. High-throughput testing in head and neck squamous cell carcinoma identifies agents with preferential activity in human papillomavirus-positive or negative cell lines.

    PubMed

    Ghasemi, Farhad; Black, Morgan; Sun, Ren X; Vizeacoumar, Frederick; Pinto, Nicole; Ruicci, Kara M; Yoo, John; Fung, Kevin; MacNeil, Danielle; Palma, David A; Winquist, Eric; Mymryk, Joe S; Ailles, Laurie A; Datti, Alessandro; Barrett, John W; Boutros, Paul C; Nichols, Anthony C

    2018-05-25

    Head and neck squamous cell carcinoma (HNSCC) is a common cancer diagnosis worldwide. Despite advances in treatment, HNSCC has very poor survival outcomes, emphasizing an ongoing need for development of improved therapeutic options. The distinct tumor characteristics of human papillomavirus (HPV)-positive vs . HPV-negative disease necessitate development of treatment strategies tailored to tumor HPV-status. High-throughput robotic screening of 1,433 biologically and pharmacologically relevant compounds at a single dose (4 μM) was carried out against 6 HPV-positive and 20 HPV-negative HNSCC cell lines for preliminary identification of therapeutically relevant compounds. Statistical analysis was further carried out to differentiate compounds with preferential activity against cell lines stratified by the HPV-status. These analyses yielded 57 compounds with higher activity in HPV-negative cell lines, and 34 with higher-activity in HPV-positive ones. Multi-point dose-response curves were generated for six of these compounds (Ryuvidine, MK-1775, SNS-032, Flavopiridol, AZD-7762 and ARP-101), confirming Ryuvidine to have preferential potency against HPV-negative cell lines, and MK-1775 to have preferential potency against HPV-positive cell lines. These data comprise a valuable resource for further investigation of compounds with therapeutic potential in the HNSCC.

  15. Doxycycline Indirectly Inhibits Proteolytic Activation of Tryptic Kallikrein-Related Peptidases and Activation of Cathelicidin

    PubMed Central

    Kanada, Kimberly N.; Nakatsuji, Teruaki; Gallo, Richard L.

    2014-01-01

    The increased abundance and activity of cathelicidin and kallikrein 5 (KLK5), a predominant trypsin-like serine protease (TLSP) in the stratum corneum, have been implicated in the pathogenesis of rosacea, a disorder treated by the use of low-dose doxycycline. Here we hypothesized that doxycycline can inhibit activation of tryptic KLKs through an indirect mechanism by inhibition of matrix metalloproteinases (MMPs) in keratinocytes. The capacity of doxycycline to directly inhibit enzyme activity was measured in surface collections of human facial skin and extracts of cultured keratinocytes by fluorescence polarization assay against fluorogenic substrates specific for MMPs or TLSPs. Doxycycline did inhibit MMP activity but did not directly inhibit serine protease activity against a fluorogenic substrate specific for TLSPs. However, when doxycycline or other MMP inhibitors were added to live keratinocytes during the production of tryptic KLKs, this treatment indirectly resulted in decreased TLSP activity. Furthermore, doxycycline under these conditions inhibited the generation of the cathelicidin peptide LL-37 from its precursor protein hCAP18, a process dependent on KLK activity. These results demonstrate that doxycycline can prevent cathelicidin activation, and suggest a previously unknown mechanism of action for doxycycline through inhibiting generation of active cathelicidin peptides. PMID:22336948

  16. Preferential Remedies for Employment Discrimination

    ERIC Educational Resources Information Center

    Edwards, Harry T.; Zaretsky, Barry L.

    1975-01-01

    An overview of the problem of preferential remedies to achieve equal employment opportunities for women and minority groups. Contends that "color blindness" will not end discrimination but that some form of "color conscious" affirmative action program must be employed. Temporary preferential treatment is justified, according to…

  17. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jan, Yi-Hua; Richardson, Jason R., E-mail: jricha3@eohsi.rutgers.edu; Baker, Angela A.

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling,more » a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40 mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation. - Highlights: • Menadione redox cycles with cytochrome P450 reductase and generates reactive oxygen species. • Redox cycling inhibits cytochrome P450-mediated parathion metabolism. • Short term administration of menadione inhibits parathion toxicity by inhibiting paraoxon formation.« less

  18. Brain tumor initiating cells adapt to restricted nutrition through preferential glucose uptake.

    PubMed

    Flavahan, William A; Wu, Qiulian; Hitomi, Masahiro; Rahim, Nasiha; Kim, Youngmi; Sloan, Andrew E; Weil, Robert J; Nakano, Ichiro; Sarkaria, Jann N; Stringer, Brett W; Day, Bryan W; Li, Meizhang; Lathia, Justin D; Rich, Jeremy N; Hjelmeland, Anita B

    2013-10-01

    Like all cancers, brain tumors require a continuous source of energy and molecular resources for new cell production. In normal brain, glucose is an essential neuronal fuel, but the blood-brain barrier limits its delivery. We now report that nutrient restriction contributes to tumor progression by enriching for brain tumor initiating cells (BTICs) owing to preferential BTIC survival and to adaptation of non-BTICs through acquisition of BTIC features. BTICs outcompete for glucose uptake by co-opting the high affinity neuronal glucose transporter, type 3 (Glut3, SLC2A3). BTICs preferentially express Glut3, and targeting Glut3 inhibits BTIC growth and tumorigenic potential. Glut3, but not Glut1, correlates with poor survival in brain tumors and other cancers; thus, tumor initiating cells may extract nutrients with high affinity. As altered metabolism represents a cancer hallmark, metabolic reprogramming may maintain the tumor hierarchy and portend poor prognosis.

  19. Brain Tumor Initiating Cells Adapt to Restricted Nutrition through Preferential Glucose Uptake

    PubMed Central

    Flavahan, William A.; Wu, Qiulian; Hitomi, Masahiro; Rahim, Nasiha; Kim, Youngmi; Sloan, Andrew E.; Weil, Robert J.; Nakano, Ichiro; Sarkaria, Jann N.; Stringer, Brett W.; Day, Bryan W.; Li, Meizhang; Lathia, Justin D.; Rich, Jeremy N.; Hjelmeland, Anita B.

    2013-01-01

    Like all cancers, brain tumors require a continuous source of energy and molecular resources for new cell production. In normal brain, glucose is an essential neuronal fuel, but the blood-brain barrier limits its delivery. We now report that nutrient restriction contributes to tumor progression by enriching for brain tumor initiating cells (BTICs) due to preferential BTIC survival and adaptation of non-BTICs through acquisition of BTIC features. BTICs outcompete for glucose uptake by co-opting the high affinity neuronal glucose transporter, type 3 (Glut3, SLC2A3). BTICs preferentially express Glut3 and targeting Glut3 inhibits BTIC growth and tumorigenic potential. Glut3, but not Glut1, correlates with poor survival in brain tumors and other cancers; thus, TICs may extract nutrients with high affinity. As altered metabolism represents a cancer hallmark, metabolic reprogramming may instruct the tumor hierarchy and portend poor prognosis. PMID:23995067

  20. Controlled CO preferential oxidation

    DOEpatents

    Meltser, M.A.; Hoch, M.M.

    1997-06-10

    Method is described for controlling the supply of air to a PROX (PReferential OXidation for CO cleanup) reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference there between correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference. 2 figs.

  1. Co-activation of RanGTPase and inhibition of GTP dissociation by Ran-GTP binding protein RanBP1.

    PubMed Central

    Bischoff, F R; Krebber, H; Smirnova, E; Dong, W; Ponstingl, H

    1995-01-01

    RCC1 (the regulator of chromosome condensation) stimulates guanine nucleotide dissociation on the Ras-related nuclear protein Ran. Both polypeptides are components of a regulatory pathway that has been implicated in regulating DNA replication, onset of and exit from mitosis, mRNA processing and transport, and import of proteins into the nucleus. In a search for further members of the RCC1-Ran signal pathway, we have identified proteins of 23, 45 and 300 kDa which tightly bind to Ran-GTP but not Ran-GDP. The purified soluble 23 kDa Ran binding protein RanBP1 does not activate RanGTPase, but increases GTP hydrolysis induced by the RanGTPase-activating protein RanGAP1 by an order of magnitude. In the absence of RanGAP, it strongly inhibits RCC1-induced exchange of Ran-bound GTP. In addition, it forms a stable complex with nucleotide-free RCC1-Ran. With these properties, it differs markedly from guanine diphosphate dissociation inhibitors which preferentially prevent the exchange of protein-bound GDP and in some cases were shown to inhibit GAP-induced GTP hydrolysis. RanBP1 is the first member of a new class of proteins regulating the binding and hydrolysis of GTP by Ras-related proteins. Images PMID:7882974

  2. Activity inhibition on municipal activated sludge by single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Parise, Alex; Thakor, Harshrajsinh; Zhang, Xiaoqi

    2014-01-01

    The objective of this study was to evaluate the respiratory activity inhibition of activated sludge used in a typical wastewater treatment plant by single-walled carbon nanotubes (SWCNTs) with different length and functionality. Four types of SWCNTs were evaluated: short, functionalized short, long, and functionalized long. Based on the effective concentration (EC50) values obtained, we determined that functionalized SWCNTs resulted in a higher microbial respiratory inhibition than non-functionalized nanotubes, and long SWCNTs gave a higher microbial respiratory inhibition than their short counterparts. Among the four types of SWCNTs studied, functionalized long exhibited the highest respiration inhibition. Scanning electron microscopy imaging indicates that the long SWCNTs dispersed more favorably after sonication than the short variety. The findings demonstrated that the toxicity of CNTs (exhibited by respiratory inhibition) is related to their physical properties; the length and functionality of SWCNTs affected the toxicity of SWCNTs in a mixed-cultured biologic system.

  3. 1,8-cineole inhibits both proliferation and elongation of BY-2 cultured tobacco cells.

    PubMed

    Yoshimura, Hiroko; Sawai, Yu; Tamotsu, Satoshi; Sakai, Atsushi

    2011-03-01

    Volatile monoterpenes such as 1,8-cineole inhibit the growth of Brassica campestris seedlings in a dose-dependent manner, and the growth-inhibitory effects are more severe for roots than hypocotyls. The preferential inhibition of root growth may be explained if the compounds inhibit cell proliferation more severely than cell elongation because root growth requires both elongation and proliferation of the constituent cells, whereas hypocotyl growth depends exclusively on elongation of existing cells. In order to examine this possibility, BY-2 suspension-cultured tobacco (Nicotiana tabacum) cells were treated with 1,8-cineole, and the inhibitory effects on cell proliferation and on cell elongation were assessed quantitatively. Treatment with 1,8-cineole lowered both the mitotic index and elongation of the cells in a dose-dependent manner, and the half-maximal inhibitory concentration (IC₅₀) for cell elongation was lower than that for cell proliferation. Moreover, 1,8-cineole also inhibited starch synthesis, with IC₅₀ lower than that for cell proliferation. Thus, the inhibitory effects of 1,8-cineole were not specific to cell proliferation; rather, 1,8-cineole seemed inhibitory to a variety of physiological activities when it was in direct contact with target cells. Based on these results, possible mechanisms for the mode of action of 1,8-cineole and for its preferential inhibition on root growth are discussed.

  4. A generalized theory of preferential linking

    NASA Astrophysics Data System (ADS)

    Hu, Haibo; Guo, Jinli; Liu, Xuan; Wang, Xiaofan

    2014-12-01

    There are diverse mechanisms driving the evolution of social networks. A key open question dealing with understanding their evolution is: How do various preferential linking mechanisms produce networks with different features? In this paper we first empirically study preferential linking phenomena in an evolving online social network, find and validate the linear preference. We propose an analyzable model which captures the real growth process of the network and reveals the underlying mechanism dominating its evolution. Furthermore based on preferential linking we propose a generalized model reproducing the evolution of online social networks, and present unified analytical results describing network characteristics for 27 preference scenarios. We study the mathematical structure of degree distributions and find that within the framework of preferential linking analytical degree distributions can only be the combinations of finite kinds of functions which are related to rational, logarithmic and inverse tangent functions, and extremely complex network structure will emerge even for very simple sublinear preferential linking. This work not only provides a verifiable origin for the emergence of various network characteristics in social networks, but bridges the micro individuals' behaviors and the global organization of social networks.

  5. Cysteine-independent activation/inhibition of heme oxygenase-2

    PubMed Central

    Vukomanovic, Dragic; Rahman, Mona N.; Maines, Mahin D.; Ozolinš, Terence RS; Szarek, Walter A.; Jia, Zongchao; Nakatsu, Kanji

    2016-01-01

    Reactive thiols of cysteine (cys) residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2) isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2) and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD) and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282. PMID:27826418

  6. Cysteine-independent activation/inhibition of heme oxygenase-2.

    PubMed

    Vukomanovic, Dragic; Rahman, Mona N; Maines, Mahin D; Ozolinš, Terence Rs; Szarek, Walter A; Jia, Zongchao; Nakatsu, Kanji

    2016-03-01

    Reactive thiols of cysteine (cys) residues in proteins play a key role in transforming chemical reactivity into a biological response. The heme oxygenase-2 (HO-2) isozyme contains two cys residues that have been implicated in binding of heme and also the regulation of its activity. In this paper, we address the question of a role for cys residues for the HO-2 inhibitors or activators designed in our laboratory. We tested the activity of full length recombinant human heme oxygenase-2 (FL-hHO-2) and its analog in which cys265 and cys282 were both replaced by alanine to determine the effect on activation by menadione (MD) and inhibition by QC-2350. Similar inhibition by QC-2350 and almost identical activation by MD was observed for both recombinant FL-hHO-2s. Our findings are interpreted to mean that thiols of FL-hHO-2s are not involved in HO-2 activation or inhibition by the compounds that have been designed and identified by us. Activation or inhibition of HO-2 by our compounds should be attributed to a mechanism other than altering binding affinity of HO-2 for heme through cys265 and cys282.

  7. Xenopus origin recognition complex (ORC) initiates DNA replication preferentially at sequences targeted by Schizosaccharomyces pombe ORC

    PubMed Central

    Kong, Daochun; Coleman, Thomas R.; DePamphilis, Melvin L.

    2003-01-01

    Budding yeast (Saccharomyces cerevisiae) origin recognition complex (ORC) requires ATP to bind specific DNA sequences, whereas fission yeast (Schizosaccharomyces pombe) ORC binds to specific, asymmetric A:T-rich sites within replication origins, independently of ATP, and frog (Xenopus laevis) ORC seems to bind DNA non-specifically. Here we show that despite these differences, ORCs are functionally conserved. Firstly, SpOrc1, SpOrc4 and SpOrc5, like those from other eukaryotes, bound ATP and exhibited ATPase activity, suggesting that ATP is required for pre-replication complex (pre-RC) assembly rather than origin specificity. Secondly, SpOrc4, which is solely responsible for binding SpORC to DNA, inhibited up to 70% of XlORC-dependent DNA replication in Xenopus egg extract by preventing XlORC from binding to chromatin and assembling pre-RCs. Chromatin-bound SpOrc4 was located at AT-rich sequences. XlORC in egg extract bound preferentially to asymmetric A:T-sequences in either bare DNA or in sperm chromatin, and it recruited XlCdc6 and XlMcm proteins to these sequences. These results reveal that XlORC initiates DNA replication preferentially at the same or similar sites to those targeted in S.pombe. PMID:12840006

  8. Inhibition of chrysin on xanthine oxidase activity and its inhibition mechanism.

    PubMed

    Lin, Suyun; Zhang, Guowen; Liao, Yijing; Pan, Junhui

    2015-11-01

    Chrysin, a bioactive flavonoid, was investigated for its potential to inhibit the activity of xanthine oxidase (XO), a key enzyme catalyzing xanthine to uric acid and finally causing gout. The kinetic analysis showed that chrysin possessed a strong inhibition on XO ability in a reversible competitive manner with IC50 value of (1.26±0.04)×10(-6)molL(-1). The results of fluorescence titrations indicated that chrysin bound to XO with high affinity, and the interaction was predominately driven by hydrogen bonds and van der Waals forces. Analysis of circular dichroism demonstrated that chrysin induced the conformational change of XO with increases in α-helix and β-sheet and reductions in β-turn and random coil structures. Molecular simulation revealed that chrysin interacted with the amino acid residues Leu648, Phe649, Glu802, Leu873, Ser876, Glu879, Arg880, Phe1009, Thr1010, Val1011 and Phe1013 located within the active cavity of XO. The mechanism of chrysin on XO activity may be the insertion of chrysin into the active site occupying the catalytic center of XO to avoid the entrance of xanthine and causing conformational changes in XO. Furthermore, the interaction assays indicated that chrysin and its structural analog apigenin exhibited an additive effect on inhibition of XO. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. KW-4679-induced inhibition of tachykininergic contraction in the guinea-pig bronchi by prejunctional inhibition of peripheral sensory nerves.

    PubMed

    Ikemura, T; Okarmura, K; Sasaki, Y; Ishi, H; Ohmori, K

    1996-03-01

    1. Sensory mechanisms play an important role in the vagal regulation of tracheobronchial smooth muscle tone. We examined the effect of KW-4679, an anti-allergic drug, on guinea-pig tachykinin-mediated contractile responses induced by electrical field stimulation (EFS) in guinea-pig bronchial muscles. 2. EFS (8 Hz, 0.5 ms, 15 V, for 15 s) evoked biphasic contractile responses in the guinea-pig isolated main bronchus in the presence of 5 microM indomethacin. The contractions consisted of a fast phase of an atropine-sensitive transient contraction and a slow phase of a sustained contraction which was inhibited by a combination of the tachykinin NK1 receptor antagonist, (+/-)-CP-96,345 (1 microM) and the NK2 receptor antagonist, SR 48969 (0.1 microM). 3. KW-4679 preferentially inhibited the slow phase in a concentration-dependent manner by 43.2 +/- 7.7% at 10 microM, whereas the drug had no effect on the fast phase at concentrations up to 10 microM. KW-4679, at a concentration of 100 microM, inhibited not only the slow phase by 49.2 +/- 11.4%, but also the fast phase by 36.8 +/- 9.3% [corrected]. 4. KW-4679 (10 microM and 100 microM) did not affect the substance P-induced or neurokinin A-induced contraction. Against the acetylcholine-induced contractile responses, 100 microM KW-4679 had a marked effect producing a 10.2 fold shift to the right in the curve. 5. The inhibitory effect of KW-4679 (10 microM) on the slow phase contraction was not influenced by treatment with naloxone (100 nM), propranolol (1 microM), thioperamide (1 microM), saclofen (50 microM), yohimbine (1 microM), methiothepin (1 microM) or methysergide (1 microM). 6. The inhibitory effect of KW-4679 (10 microM) on the slow phase contraction was not influenced by treatment with intermediate or large conductance Ca(2+)-activated K+ channel blockers (charybdotoxin (10 nM) or iberiotoxin (10 nM)), but suppressed by treatment with small conductance Ca(2+)-activated K+ channel blockers, apamin (500 nM) or

  10. Comparing perceptual and preferential decision making.

    PubMed

    Dutilh, Gilles; Rieskamp, Jörg

    2016-06-01

    Perceptual and preferential decision making have been studied largely in isolation. Perceptual decisions are considered to be at a non-deliberative cognitive level and have an outside criterion that defines the quality of decisions. Preferential decisions are considered to be at a higher cognitive level and the quality of decisions depend on the decision maker's subjective goals. Besides these crucial differences, both types of decisions also have in common that uncertain information about the choice situation has to be processed before a decision can be made. The present work aims to acknowledge the commonalities of both types of decision making to lay bare the crucial differences. For this aim we examine perceptual and preferential decisions with a novel choice paradigm that uses the identical stimulus material for both types of decisions. This paradigm allows us to model the decisions and response times of both types of decisions with the same sequential sampling model, the drift diffusion model. The results illustrate that the different incentive structure in both types of tasks changes people's behavior so that they process information more efficiently and respond more cautiously in the perceptual as compared to the preferential task. These findings set out a perspective for further integration of perceptual and preferential decision making in a single ramework.

  11. Hepatitis B Virus Lacks Immune Activating Capacity, but Actively Inhibits Plasmacytoid Dendritic Cell Function

    PubMed Central

    Woltman, Andrea M.; Shi, Cui C.; Janssen, Harry L. A.

    2011-01-01

    Chronic hepatitis B virus (HBV) infection is caused by inadequate anti-viral immunity. Activation of plasmacytoid dendritic cells (pDC) leading to IFNα production is important for effective anti-viral immunity. Hepatitis B virus (HBV) infection lacks IFNα induction in animal models and patients and chronic HBV patients display impaired IFNα production by pDC. Therefore, HBV and HBV-derived proteins were examined for their effect on human pDC in vitro. In addition, the in vitro findings were compared to the function of pDC derived from chronic HBV patients ex vivo. In contrast to other viruses, HBV did not activate pDC. Moreover, HBV and HBsAg abrogated CpG-A/TLR9-induced, but not Loxoribine/TLR7-induced, mTOR-mediated S6 phosphorylation, subsequent IRF7 phosphorylation and IFNα gene transcription. HBV/HBsAg also diminished upregulation of co-stimulatory molecules, production of TNFα, IP-10 and IL-6 and pDC-induced NK cell function, whereas TLR7-induced pDC function was hardly affected. In line, HBsAg preferentially bound to TLR9-triggered pDC demonstrating that once pDC are able to bind HBV/HBsAg, the virus exerts its immune regulatory effect. HBV not only directly interfered with pDC function, but also indirectly by interfering with monocyte-pDC interaction. Also HBeAg diminished pDC function to a certain extent, but via another unknown mechanism. Interestingly, patients with HBeAg-positive chronic hepatitis B displayed impaired CpG-induced IFNα production by pDC without significant alterations in Loxoribine-induced pDC function compared to HBeAg-negative patients and healthy controls. The lack of activation and the active inhibition of pDC by HBV may both contribute to HBV persistence. The finding that the interaction between pDC and HBV may change upon activation may aid in the identification of a scavenging receptor supporting immunosuppressive effects of HBV and also in the design of novel treatment strategies for chronic HBV. PMID:21246041

  12. Metformin and Its Sulfenamide Prodrugs Inhibit Human Cholinesterase Activity.

    PubMed

    Markowicz-Piasecka, Magdalena; Sikora, Joanna; Mateusiak, Łukasz; Mikiciuk-Olasik, Elżbieta; Huttunen, Kristiina M

    2017-01-01

    The results of epidemiological and pathophysiological studies suggest that type 2 diabetes mellitus (T2DM) may predispose to Alzheimer's disease (AD). The two conditions present similar glucose levels, insulin resistance, and biochemical etiologies such as inflammation and oxidative stress. The diabetic state also contributes to increased acetylcholinesterase (AChE) activity, which is one of the factors leading to neurodegeneration in AD. The aim of this study was to assess in vitro the effects of metformin, phenformin, and metformin sulfenamide prodrugs on the activity of human AChE and butyrylcholinesterase (BuChE) and establish the type of inhibition. Metformin inhibited 50% of the AChE activity at micromolar concentrations (2.35  μ mol/mL, mixed type of inhibition) and seemed to be selective towards AChE since it presented low anti-BuChE activity. The tested metformin prodrugs inhibited cholinesterases (ChE) at nanomolar range and thus were more active than metformin or phenformin. The cyclohexyl sulfenamide prodrug demonstrated the highest activity towards both AChE (IC 50  = 890 nmol/mL, noncompetitive inhibition) and BuChE (IC 50  = 28 nmol/mL, mixed type inhibition), while the octyl sulfenamide prodrug did not present anti-AChE activity, but exhibited mixed inhibition towards BuChE (IC 50  = 184 nmol/mL). Therefore, these two bulkier prodrugs were concluded to be the most selective compounds for BuChE over AChE. In conclusion, it was demonstrated that biguanides present a novel class of inhibitors for AChE and BuChE and encourages further studies of these compounds for developing both selective and nonselective inhibitors of ChEs in the future.

  13. Closed-Loop Efficient Searching of Optimal Electrical Stimulation Parameters for Preferential Excitation of Retinal Ganglion Cells

    PubMed Central

    Guo, Tianruo; Yang, Chih Yu; Tsai, David; Muralidharan, Madhuvanthi; Suaning, Gregg J.; Morley, John W.; Dokos, Socrates; Lovell, Nigel H.

    2018-01-01

    The ability for visual prostheses to preferentially activate functionally-distinct retinal ganglion cells (RGCs) is important for improving visual perception. This study investigates the use of high frequency stimulation (HFS) to elicit RGC activation, using a closed-loop algorithm to search for optimal stimulation parameters for preferential ON and OFF RGC activation, resembling natural physiological neural encoding in response to visual stimuli. We evaluated the performance of a wide range of electrical stimulation amplitudes and frequencies on RGC responses in vitro using murine retinal preparations. It was possible to preferentially excite either ON or OFF RGCs by adjusting amplitudes and frequencies in HFS. ON RGCs can be preferentially activated at relatively higher stimulation amplitudes (>150 μA) and frequencies (2–6.25 kHz) while OFF RGCs are activated by lower stimulation amplitudes (40–90 μA) across all tested frequencies (1–6.25 kHz). These stimuli also showed great promise in eliciting RGC responses that parallel natural RGC encoding: ON RGCs exhibited an increase in spiking activity during electrical stimulation while OFF RGCs exhibited decreased spiking activity, given the same stimulation amplitude. In conjunction with the in vitro studies, in silico simulations indicated that optimal HFS parameters could be rapidly identified in practice, whilst sampling spiking activity of relevant neuronal subtypes. This closed-loop approach represents a step forward in modulating stimulation parameters to achieve appropriate neural encoding in retinal prostheses, advancing control over RGC subtypes activated by electrical stimulation. PMID:29615857

  14. Interneuron-mediated inhibition synchronizes neuronal activity during slow oscillation.

    PubMed

    Chen, Jen-Yung; Chauvette, Sylvain; Skorheim, Steven; Timofeev, Igor; Bazhenov, Maxim

    2012-08-15

    The signature of slow-wave sleep in the electroencephalogram (EEG) is large-amplitude fluctuation of the field potential, which reflects synchronous alternation of activity and silence across cortical neurons. While initiation of the active cortical states during sleep slow oscillation has been intensively studied, the biological mechanisms which drive the network transition from an active state to silence remain poorly understood. In the current study, using a combination of in vivo electrophysiology and thalamocortical network simulation, we explored the impact of intrinsic and synaptic inhibition on state transition during sleep slow oscillation. We found that in normal physiological conditions, synaptic inhibition controls the duration and the synchrony of active state termination. The decline of interneuron-mediated inhibition led to asynchronous downward transition across the cortical network and broke the regular slow oscillation pattern. Furthermore, in both in vivo experiment and computational modelling, we revealed that when the level of synaptic inhibition was reduced significantly, it led to a recovery of synchronized oscillations in the form of seizure-like bursting activity. In this condition, the fast active state termination was mediated by intrinsic hyperpolarizing conductances. Our study highlights the significance of both intrinsic and synaptic inhibition in manipulating sleep slow rhythms.

  15. Interneuron-mediated inhibition synchronizes neuronal activity during slow oscillation

    PubMed Central

    Chen, Jen-Yung; Chauvette, Sylvain; Skorheim, Steven; Timofeev, Igor; Bazhenov, Maxim

    2012-01-01

    The signature of slow-wave sleep in the electroencephalogram (EEG) is large-amplitude fluctuation of the field potential, which reflects synchronous alternation of activity and silence across cortical neurons. While initiation of the active cortical states during sleep slow oscillation has been intensively studied, the biological mechanisms which drive the network transition from an active state to silence remain poorly understood. In the current study, using a combination of in vivo electrophysiology and thalamocortical network simulation, we explored the impact of intrinsic and synaptic inhibition on state transition during sleep slow oscillation. We found that in normal physiological conditions, synaptic inhibition controls the duration and the synchrony of active state termination. The decline of interneuron-mediated inhibition led to asynchronous downward transition across the cortical network and broke the regular slow oscillation pattern. Furthermore, in both in vivo experiment and computational modelling, we revealed that when the level of synaptic inhibition was reduced significantly, it led to a recovery of synchronized oscillations in the form of seizure-like bursting activity. In this condition, the fast active state termination was mediated by intrinsic hyperpolarizing conductances. Our study highlights the significance of both intrinsic and synaptic inhibition in manipulating sleep slow rhythms. PMID:22641778

  16. Investigation of Preferential Flow in Low Impact Development Practice

    NASA Astrophysics Data System (ADS)

    Liu, L.; Cao, R.; Wang, C.; Jiang, W.; Wang, J.; Xia, Z.

    2016-12-01

    The characteristics of preferential flow in soil affect Low Impact Development (LID) practices in two aspects. On the one hand, preferential flow may facilitate drainage of stormwater by causing non-uniform movement of water through a small portion of media (such as cracks and holes), and thus leading to much faster transport of water and solutes in one specific direction than others. On the other hand, within a certain ranges, preferential flow may weaken the subgrade capacity of pressure and/or shear stress resistance. Therefore, for the purpose of improving LID practices, there may exist an optimum scenario with a high allowable flowrate and least negative impact of resistance capacity for a soil layer. This project aims to assist the LID design by exploring the features of preferential flow in different soil compositions, studying how different flow paths affect the stability of subgrade, preliminarily analyzing the sensitivity of preferential flow impacting on drainage capacity and subgrade stability in the LID, and further optimizing LID practices. Accordingly, the concepts of Essential Direction Path, Unessential Direction Path and the Sensitivity Coefficient are defined and analyzed to simulate a hypothetical funneling scenario in LID practice. Both irrigation apparatus experiments and numerical models are utilized in this research to investigate the features of preferential flow, effective strength and overall shear strength. The main conclusions include: (1) Investigation of preferential flow characteristics in essential direction path and unessential direction path, respectively; (2) Optimum design of preferential flow in LID practice; (3) Transport capacity determination of preferential flow path in different soils; (4) Study of preferential flow impact on roadbed stability. KEY WORDS: Preferential Flow, Subgrade stability, LID, Sensitivity Coefficient, Funneling Preferential Flow Path

  17. Inhibition of SHP2-mediated dephosphorylation of Ras suppresses oncogenesis

    PubMed Central

    Bunda, Severa; Burrell, Kelly; Heir, Pardeep; Zeng, Lifan; Alamsahebpour, Amir; Kano, Yoshihito; Raught, Brian; Zhang, Zhong-Yin; Zadeh, Gelareh; Ohh, Michael

    2015-01-01

    Ras is phosphorylated on a conserved tyrosine at position 32 within the switch I region via Src kinase. This phosphorylation inhibits the binding of effector Raf while promoting the engagement of GTPase-activating protein (GAP) and GTP hydrolysis. Here we identify SHP2 as the ubiquitously expressed tyrosine phosphatase that preferentially binds to and dephosphorylates Ras to increase its association with Raf and activate downstream proliferative Ras/ERK/MAPK signalling. In comparison to normal astrocytes, SHP2 activity is elevated in astrocytes isolated from glioblastoma multiforme (GBM)-prone H-Ras(12V) knock-in mice as well as in glioma cell lines and patient-derived GBM specimens exhibiting hyperactive Ras. Pharmacologic inhibition of SHP2 activity attenuates cell proliferation, soft-agar colony formation and orthotopic GBM growth in NOD/SCID mice and decelerates the progression of low-grade astrocytoma to GBM in a spontaneous transgenic glioma mouse model. These results identify SHP2 as a direct activator of Ras and a potential therapeutic target for cancers driven by a previously ‘undruggable' oncogenic or hyperactive Ras. PMID:26617336

  18. Naringin suppresses the development of glioblastoma by inhibiting FAK activity.

    PubMed

    Li, Jinjiang; Dong, Yushu; Hao, Guangzhi; Wang, Bao; Wang, Julei; Liang, Yong; Liu, Yangyang; Zhen, Endi; Feng, Dayun; Liang, Guobiao

    2017-01-01

    As the most common and lethal primary malignant brain cancer, glioblastoma is hard to timely diagnose and sensitive therapeutic monitoring. It is essential to develop new and effective drugs for glioblastoma multiform. Naringin belongs to citrus flavonoids and was found to display strong anti-inflammatory, antioxidant and antitumor activities. In this report, we found that naringin can specifically inhibit the kinase activity of FAK and suppress the FAK p-Try397 and its downstream pathway in glioblastoma cells. Our study showed out that naringin can inhibit cell proliferation by inhibiting FAK/cyclin D1 pathway, promote cell apoptosis through influencing FAK/bads pathway, at the same time, it can also inhibit cell invasion and metastasis by inhibiting the FAK/mmps pathway. All these showed that naringin exerts the anti-tumor effects in U87 MG by inhibiting the kinase activity of FAK.

  19. Vitamin K3 (menadione) redox cycling inhibits cytochrome P450-mediated metabolism and inhibits parathion intoxication.

    PubMed

    Jan, Yi-Hua; Richardson, Jason R; Baker, Angela A; Mishin, Vladimir; Heck, Diane E; Laskin, Debra L; Laskin, Jeffrey D

    2015-10-01

    Parathion, a widely used organophosphate insecticide, is considered a high priority chemical threat. Parathion toxicity is dependent on its metabolism by the cytochrome P450 system to paraoxon (diethyl 4-nitrophenyl phosphate), a cytotoxic metabolite. As an effective inhibitor of cholinesterases, paraoxon causes the accumulation of acetylcholine in synapses and overstimulation of nicotinic and muscarinic cholinergic receptors, leading to characteristic signs of organophosphate poisoning. Inhibition of parathion metabolism to paraoxon represents a potential approach to counter parathion toxicity. Herein, we demonstrate that menadione (methyl-1,4-naphthoquinone, vitamin K3) is a potent inhibitor of cytochrome P450-mediated metabolism of parathion. Menadione is active in redox cycling, a reaction mediated by NADPH-cytochrome P450 reductase that preferentially uses electrons from NADPH at the expense of their supply to the P450s. Using human recombinant CYP 1A2, 2B6, 3A4 and human liver microsomes, menadione was found to inhibit the formation of paraoxon from parathion. Administration of menadione bisulfite (40mg/kg, ip) to rats also reduced parathion-induced inhibition of brain cholinesterase activity, as well as parathion-induced tremors and the progression of other signs and symptoms of parathion poisoning. These data suggest that redox cycling compounds, such as menadione, have the potential to effectively mitigate the toxicity of organophosphorus pesticides including parathion which require cytochrome P450-mediated activation. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Ciclopirox olamine inhibits mTORC1 signaling by activation of AMPK.

    PubMed

    Zhou, Hongyu; Shang, Chaowei; Wang, Min; Shen, Tao; Kong, Lingmei; Yu, Chunlei; Ye, Zhennan; Luo, Yan; Liu, Lei; Li, Yan; Huang, Shile

    2016-09-15

    Ciclopirox olamine (CPX), an off-patent antifungal agent, has recently been identified as a potential anticancer agent. The mammalian target of rapamycin (mTOR) is a central controller of cell growth, proliferation and survival. Little is known about whether and how CPX executes its anticancer action by inhibiting mTOR. Here we show that CPX inhibited the phosphorylation of p70 S6 kinase 1 (S6K1) and eukaryotic initiation factor 4E binding protein 1 (4E-BP1), two downstream effector molecules of mTOR complex 1 (mTORC1), in a spectrum of human tumor cells, indicating that CPX inhibits mTORC1 signaling. Using rhabdomyosarcoma cells as an experimental model, we found that expression of constitutively active mTOR (E2419K) conferred resistance to CPX inhibition of cell proliferation, suggesting that CPX inhibition of mTORC1 contributed to its anticancer effect. In line with this, treatment with CPX inhibited tumor growth and concurrently suppressed mTORC1 signaling in RD xenografts. Mechanistically, CPX inhibition of mTORC1 was neither via inhibition of IGF-I receptor or phosphoinositide 3-kinase (PI3K), nor by activation of phosphatase and tensin homolog (PTEN). Instead, CPX inhibition of mTORC1 was attributed to activation of AMP-activated protein kinase (AMPK)-tuberous sclerosis complexes (TSC)/raptor pathways. This is supported by the findings that CPX activated AMPK; inhibition of AMPK with Compound C or ectopic expression of dominant negative AMPKα partially prevented CPX from inhibiting mTORC1; silencing TSC2 attenuated CPX inhibition of mTORC1; and CPX also increased AMPK-mediated phosphorylation of raptor (S792). Therefore, the results indicate that CPX exerts the anticancer effect by activating AMPK, resulting in inhibition of mTORC1 signaling. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Inhibition of Super-Enhancer Activity in Autoinflammatory Site-Derived T Cells Reduces Disease-Associated Gene Expression.

    PubMed

    Peeters, Janneke G C; Vervoort, Stephin J; Tan, Sander C; Mijnheer, Gerdien; de Roock, Sytze; Vastert, Sebastiaan J; Nieuwenhuis, Edward E S; van Wijk, Femke; Prakken, Berent J; Creyghton, Menno P; Coffer, Paul J; Mokry, Michal; van Loosdregt, Jorg

    2015-09-29

    The underlying molecular mechanisms for many autoimmune diseases are poorly understood. Juvenile idiopathic arthritis (JIA) is an exceptionally well-suited model for studying autoimmune diseases due to its early onset and the possibility to analyze cells derived from the site of inflammation. Epigenetic profiling, utilizing primary JIA patient-derived cells, can contribute to the understanding of autoimmune diseases. With H3K27ac chromatin immunoprecipitation, we identified a disease-specific, inflammation-associated, typical enhancer and super-enhancer signature in JIA patient synovial-fluid-derived CD4(+) memory/effector T cells. RNA sequencing of autoinflammatory site-derived patient T cells revealed that BET inhibition, utilizing JQ1, inhibited immune-related super-enhancers and preferentially reduced disease-associated gene expression, including cytokine-related processes. Altogether, these results demonstrate the potential use of enhancer profiling to identify disease mediators and provide evidence for BET inhibition as a possible therapeutic approach for the treatment of autoimmune diseases. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  2. Preferential flow occurs in unsaturated conditions

    USGS Publications Warehouse

    Nimmo, John R.

    2012-01-01

    Because it commonly generates high-speed, high-volume flow with minimal exposure to solid earth materials, preferential flow in the unsaturated zone is a dominant influence in many problems of infiltration, recharge, contaminant transport, and ecohydrology. By definition, preferential flow occurs in a portion of a medium – that is, a preferred part, whether a pathway, pore, or macroscopic subvolume. There are many possible classification schemes, but usual consideration of preferential flow includes macropore or fracture flow, funneled flow determined by macroscale heterogeneities, and fingered flow determined by hydraulic instability rather than intrinsic heterogeneity. That preferential flow is spatially concentrated associates it with other characteristics that are typical, although not defining: it tends to be unusually fast, to transport high fluxes, and to occur with hydraulic disequilibrium within the medium. It also has a tendency to occur in association with large conduits and high water content, although these are less universal than is commonly assumed. Predictive unsaturated-zone flow models in common use employ several different criteria for when and where preferential flow occurs, almost always requiring a nearly saturated medium. A threshold to be exceeded may be specified in terms of the following (i) water content; (ii) matric potential, typically a value high enough to cause capillary filling in a macropore of minimum size; (iii) infiltration capacity or other indication of incipient surface ponding; or (iv) other conditions related to total filling of certain pores. Yet preferential flow does occur without meeting these criteria. My purpose in this commentary is to point out important exceptions and implications of ignoring them. Some of these pertain mainly to macropore flow, others to fingered or funneled flow, and others to combined or undifferentiated flow modes.

  3. Thrombomodulin inhibits the activation of eosinophils and mast cells.

    PubMed

    Roeen, Ziaurahman; Toda, Masaaki; D'Alessandro-Gabazza, Corina N; Onishi, Masahiro; Kobayashi, Tetsu; Yasuma, Taro; Urawa, Masahito; Taguchi, Osamu; Gabazza, Esteban C

    2015-01-01

    Eosinophils and mast cells play critical roles in the pathogenesis of bronchial asthma. Activation of both cells leads to the release of pro-inflammatory mediators in the airway of asthmatic patients. Recently, we have shown that inhaled thrombomodulin inhibits allergic bronchial asthma in a mouse model. In the present study, we hypothesize that thrombomodulin can inhibit the activation of eosinophils and mast cells. The effect of thrombomodulin on the activation and release of inflammatory mediators from eosinophils and mast cells was evaluated. Thrombomodulin inhibited the eotaxin-induced chemotaxis, upregulation of CD11b and degranulation of eosinophils. Treatment with thrombomodulin also significantly suppressed the degranulation and synthesis of inflammatory cytokines and chemokines in eosinophils and mast cells. Mice treated with a low-dose of inhaled thrombomodulin have decreased number of eosinophils and activated mast cells and Th2 cytokines in the lungs compared to untreated mice. The results of this study suggest that thrombomodulin may modulate allergic responses by inhibiting the activation of both eosinophils and mast cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. GABA-A Receptors Mediate Tonic Inhibition and Neurosteroid Sensitivity in the Brain.

    PubMed

    Reddy, Doodipala Samba

    2018-01-01

    Neurosteroids like allopregnanolone (AP) are positive allosteric modulators of synaptic and extrasynaptic GABA-A receptors. AP and related neurosteroids exhibit a greater potency for δ-containing extrasynaptic receptors. The δGABA-A receptors, which are expressed extrasynaptically in the dentate gyrus and other regions, contribute to tonic inhibition, promoting network shunting as well as reducing seizure susceptibility. Levels of endogenous neurosteroids fluctuate with ovarian cycle. Natural and synthetic neurosteroids maximally potentiate tonic inhibition in the hippocampus and provide robust protection against a variety of limbic seizures and status epilepticus. Recently, a consensus neurosteroid pharmacophore model has been proposed at extrasynaptic δGABA-A receptors based on structure-activity relationship for functional activation of tonic currents and seizure protection. Aside from anticonvulsant actions, neurosteroids have been found to be powerful anxiolytic and anesthetic agents. Neurosteroids and Zn 2+ have preferential affinity for δ-containing receptors. Thus, Zn 2+ can prevent neurosteroid activation of extrasynaptic δGABA-A receptor-mediated tonic inhibition. Recently, we demonstrated that Zn 2+ selectively inhibits extrasynaptic δGABA-A receptors and thereby fully prevents AP activation of tonic inhibition and seizure protection. We confirmed that neurosteroids exhibit greater sensitivity at extrasynaptic δGABA-A receptors. Overall, extrasynaptic GABA-A receptors are primary mediators of tonic inhibition in the brain and play a key role in the pathophysiology of epilepsy and other neurological disorders. © 2018 Elsevier Inc. All rights reserved.

  5. Activated AMPK inhibits PPAR-{alpha} and PPAR-{gamma} transcriptional activity in hepatoma cells.

    PubMed

    Sozio, Margaret S; Lu, Changyue; Zeng, Yan; Liangpunsakul, Suthat; Crabb, David W

    2011-10-01

    AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor-α (PPAR-α) are critical regulators of short-term and long-term fatty acid oxidation, respectively. We examined whether the activities of these molecules were coordinately regulated. H4IIEC3 cells were transfected with PPAR-α and PPAR-γ expression plasmids and a peroxisome-proliferator-response element (PPRE) luciferase reporter plasmid. The cells were treated with PPAR agonists (WY-14,643 and rosiglitazone), AMPK activators 5-aminoimidazole-4-carboxamide riboside (AICAR) and metformin, and the AMPK inhibitor compound C. Both AICAR and metformin decreased basal and WY-14,643-stimulated PPAR-α activity; compound C increased agonist-stimulated reporter activity and partially reversed the effect of the AMPK activators. Similar effects on PPAR-γ were seen, with both AICAR and metformin inhibiting PPRE reporter activity. Compound C increased basal PPAR-γ activity and rosiglitazone-stimulated activity. In contrast, retinoic acid receptor-α (RAR-α), another nuclear receptor that dimerizes with retinoid X receptor (RXR), was largely unaffected by the AMPK activators. Compound C modestly increased AM580 (an RAR agonist)-stimulated activity. The AMPK activators did not affect PPAR-α binding to DNA, and there was no consistent correlation between effects of the AMPK activators and inhibitor on PPAR and the nuclear localization of AMPK-α subunits. Expression of either a constitutively active or dominant negative AMPK-α inhibited basal and WY-14,643-stimulated PPAR-α activity and basal and rosiglitazone-stimulated PPAR-γ activity. We concluded that the AMPK activators AICAR and metformin inhibited transcriptional activities of PPAR-α and PPAR-γ, whereas inhibition of AMPK with compound C activated both PPARs. The effects of AMPK do not appear to be mediated through effects on RXR or on PPAR/RXR binding to DNA. These effects are independent of kinase activity and instead appear to

  6. Modeling Preferential Admissions at Elite Liberal Arts Colleges

    ERIC Educational Resources Information Center

    Cockburn, Sally; Hewitt, Gordon; Kelly, Timothy

    2013-01-01

    This paper presents the results of a model that simulates the effects of varying preferential admissions policies on the academic profile of a set of 35 small liberal arts colleges. An underlying assumption is that all schools in the set use the same ratio of preferential to non-preferential admissions. The model predicts that even drastic changes…

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

    PubMed

    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.

  8. Inhibition of existing denitrification enzyme activity by chloramphenicol

    USGS Publications Warehouse

    Brooks, M.H.; Smith, R.L.; Macalady, D.L.

    1992-01-01

    Chloramphenicol completely inhibited the activity of existing denitrification enzymes in acetylene-block incubations with (i) sediments from a nitrate-contaminated aquifer and (ii) a continuous culture of denitrifying groundwater bacteria. Control flasks with no antibiotic produced significant amounts of nitrous oxide in the same time period. Amendment with chloramphenicol after nitrous oxide production had begun resulted in a significant decrease in the rate of nitrous oxide production. Chloramphenicol also decreased (>50%) the activity of existing denitrification enzymes in pure cultures of Pseudomonas denitrificans that were harvested during log- phase growth and maintained for 2 weeks in a starvation medium lacking electron donor. Short-term time courses of nitrate consumption and nitrous oxide production in the presence of acetylene with P. denitrificans undergoing carbon starvation were performed under optimal conditions designed to mimic denitrification enzyme activity assays used with soils. Time courses were linear for both chloramphenicol and control flasks, and rate estimates for the two treatments were significantly different at the 95% confidence level. Complete or partial inhibition of existing enzyme activity is not consistent with the current understanding of the mode of action of chloramphenicol or current practice, in which the compound is frequently employed to inhibit de novo protein synthesis during the course of microbial activity assays. The results of this study demonstrate that chloramphenicol amendment can inhibit the activity of existing denitrification enzymes and suggest that caution is needed in the design and interpretation of denitrification activity assays in which chloramphenicol is used to prevent new protein synthesis.

  9. Preferential Affirmative Action.

    ERIC Educational Resources Information Center

    Bell, Derrick A., Jr.

    1982-01-01

    Discusses the philosophical rationale for preferential affirmative action presented by Daniel C. Maguire in "A New American Justice." Maintains that self-interest bars present society's acceptance of Maguire's theories of justice, as demonstrated in negative reactions to the Harvard Law Review's affirmative action plan. (MJL)

  10. Feedback inhibition of nitric oxide synthase activity by nitric oxide.

    PubMed Central

    Assreuy, J.; Cunha, F. Q.; Liew, F. Y.; Moncada, S.

    1993-01-01

    1. A murine macrophage cell line, J774, expressed nitric oxide (NO) synthase activity in response to interferon-gamma (IFN-gamma, 10 u ml-1) plus lipopolysaccharide (LPS, 10 ng ml-1). The enzyme activity was first detectable 6 h after incubation, peaked at 12 h and became undetectable after 48 h. 2. The decline in the NO synthase activity was not due to inhibition by stable substances secreted by the cells into the culture supernatant. 3. The decline in the NO synthase activity was significantly slowed down in cells cultured in a low L-arginine medium or with added haemoglobin, suggesting that NO may be involved in a feedback inhibitory mechanism. 4. The addition of NO generators, S-nitroso-acetyl-penicillamine (SNAP) or S-nitroso-glutathione (GSNO) markedly inhibited the NO synthase activity in a dose-dependent manner. The effect of NO on the enzyme was not due to the inhibition of de novo protein synthesis. 5. SNAP directly inhibited the inducible NO synthase extracted from activated J774 cells, as well as the constitutive NO synthase extracted from the rat brain. 6. The enzyme activity of J774 cells was not restored after the removal of SNAP by gel filtration, suggesting that NO inhibits NO synthase irreversibly. PMID:7682140

  11. Antitumor Activity and Mechanism of Action of the Cyclopenta[b]benzofuran, Silvestrol

    PubMed Central

    Cencic, Regina; Carrier, Marilyn; Galicia-Vázquez, Gabriela; Bordeleau, Marie-Eve; Sukarieh, Rami; Bourdeau, Annie; Brem, Brigitte; Teodoro, Jose G.; Greger, Harald; Tremblay, Michel L.; Porco, John A.; Pelletier, Jerry

    2009-01-01

    Background Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. Methodology/Principal Findings Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. Conclusions/Significance Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals. PMID:19401772

  12. Antitumor activity and mechanism of action of the cyclopenta[b]benzofuran, silvestrol.

    PubMed

    Cencic, Regina; Carrier, Marilyn; Galicia-Vázquez, Gabriela; Bordeleau, Marie-Eve; Sukarieh, Rami; Bourdeau, Annie; Brem, Brigitte; Teodoro, Jose G; Greger, Harald; Tremblay, Michel L; Porco, John A; Pelletier, Jerry

    2009-01-01

    Flavaglines are a family of natural products from the genus Aglaia that exhibit anti-cancer activity in vitro and in vivo and inhibit translation initiation. They have been shown to modulate the activity of eIF4A, the DEAD-box RNA helicase subunit of the eukaryotic initiation factor (eIF) 4F complex, a complex that stimulates ribosome recruitment during translation initiation. One flavagline, silvestrol, is capable of modulating chemosensitivity in a mechanism-based mouse model. Among a number of flavagline family members tested herein, we find that silvestrol is the more potent translation inhibitor among these. We find that silvestrol impairs the ribosome recruitment step of translation initiation by affecting the composition of the eukaryotic initiation factor (eIF) 4F complex. We show that silvestrol exhibits significant anticancer activity in human breast and prostate cancer xenograft models, and that this is associated with increased apoptosis, decreased proliferation, and inhibition of angiogenesis. We demonstrate that targeting translation by silvestrol results in preferential inhibition of weakly initiating mRNAs. Our results indicate that silvestrol is a potent anti-cancer compound in vivo that exerts its activity by affecting survival pathways as well as angiogenesis. We propose that silvestrol mediates its effects by preferentially inhibiting translation of malignancy-related mRNAs. Silvestrol appears to be well tolerated in animals.

  13. Preferential attachment in evolutionary earthquake networks

    NASA Astrophysics Data System (ADS)

    Rezaei, Soghra; Moghaddasi, Hanieh; Darooneh, Amir Hossein

    2018-04-01

    Earthquakes as spatio-temporal complex systems have been recently studied using complex network theory. Seismic networks are dynamical networks due to addition of new seismic events over time leading to establishing new nodes and links to the network. Here we have constructed Iran and Italy seismic networks based on Hybrid Model and testified the preferential attachment hypothesis for the connection of new nodes which states that it is more probable for newly added nodes to join the highly connected nodes comparing to the less connected ones. We showed that the preferential attachment is present in the case of earthquakes network and the attachment rate has a linear relationship with node degree. We have also found the seismic passive points, the most probable points to be influenced by other seismic places, using their preferential attachment values.

  14. The Ability To Activate and Inhibit Speeded Responses: Separate Developmental Trends.

    ERIC Educational Resources Information Center

    Band, Guido P. H.; van der Molen, Maurits W.; Overtoom, Carin C. E.; Verbaten, Marinus N.

    2000-01-01

    Compared 5-, 8-, and 11-year-olds and young adults on 6 speeded performance tasks, 4 requiring an inhibition of response activation. Analyzed reaction and inhibition times; found support for hypothesis of generalized developmental changes in response activation, but revealed less pronounced development of inhibition. Concluded that a nonselective…

  15. Hili Inhibits HIV Replication in Activated T Cells.

    PubMed

    Peterlin, B Matija; Liu, Pingyang; Wang, Xiaoyun; Cary, Daniele; Shao, Wei; Leoz, Marie; Hong, Tian; Pan, Tao; Fujinaga, Koh

    2017-06-01

    P-element-induced wimpy-like (Piwil) proteins restrict the replication of mobile genetic elements in the germ line. They are also expressed in many transformed cell lines. In this study, we discovered that the human Piwil 2 (Hili) protein can also inhibit HIV replication, especially in activated CD4 + T cells that are the preferred target cells for this virus in the infected host. Although resting cells did not express Hili, its expression was rapidly induced following T cell activation. In these cells and transformed cell lines, depletion of Hili increased levels of viral proteins and new viral particles. Further studies revealed that Hili binds to tRNA. Some of the tRNAs represent rare tRNA species, whose codons are overrepresented in the viral genome. Targeting tRNA Arg (UCU) with an antisense oligonucleotide replicated effects of Hili and also inhibited HIV replication. Finally, Hili also inhibited the retrotransposition of the endogenous intracysternal A particle (IAP) by a similar mechanism. Thus, Hili joins a list of host proteins that inhibit the replication of HIV and other mobile genetic elements. IMPORTANCE Piwil proteins inhibit the movement of mobile genetic elements in the germ line. In their absence, sperm does not form and male mice are sterile. This inhibition is thought to occur via small Piwi-interacting RNAs (piRNAs). However, in some species and in human somatic cells, Piwil proteins bind primarily to tRNA. In this report, we demonstrate that human Piwil proteins, especially Hili, not only bind to select tRNA species, including rare tRNAs, but also inhibit HIV replication. Importantly, T cell activation induces the expression of Hili in CD4 + T cells. Since Hili also inhibited the movement of an endogenous retrovirus (IAP), our finding shed new light on this intracellular resistance to exogenous and endogenous retroviruses as well as other mobile genetic elements. Copyright © 2017 American Society for Microbiology.

  16. Nitric oxide prodrug JS-K inhibits ubiquitin E1 and kills tumor cells retaining wild-type p53.

    PubMed

    Kitagaki, J; Yang, Y; Saavedra, J E; Colburn, N H; Keefer, L K; Perantoni, A O

    2009-01-29

    Nitric oxide (NO) is a major effector molecule in cancer prevention. A number of studies have shown that NO prodrug JS-K (O(2)-(2,4-dinitrophenyl) 1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2-diolate) induces apoptotic cell death in vitro and in vivo, indicating that it is a promising new therapeutic for cancer. However, the mechanism of its tumor-killing activity remains unclear. Ubiquitin plays an important role in the regulation of tumorigenesis and cell apoptosis. Our earlier report has shown that inactivation of the ubiquitin system through blocking E1 (ubiquitin-activating enzyme) activity preferentially induces apoptosis in p53-expressing transformed cells. As E1 has an active cysteine residue that could potentially interact with NO, we hypothesized that JS-K could inactivate E1 activity. E1 activity was evaluated by detecting ubiquitin-E1 conjugates through immunoblotting. JS-K strikingly inhibits the ubiquitin-E1 thioester formation in cells in a dose-dependent manner with an IC(50) of approximately 2 microM, whereas a JS-K analog that cannot release NO did not affect these levels in cells. Moreover, JS-K decreases total ubiquitylated proteins and increases p53 levels, which is mainly regulated by ubiquitin and proteasomal degradation. Furthermore, JS-K preferentially induces cell apoptosis in p53-expressing transformed cells. These findings indicate that JS-K inhibits E1 activity and kills transformed cells harboring wild-type p53.

  17. Acrolein preferentially damages nucleolus eliciting ribosomal stress and apoptosis in human cancer cells.

    PubMed

    Wang, Hsiang-Tsui; Chen, Tzu-Ying; Weng, Ching-Wen; Yang, Chun-Hsiang; Tang, Moon-Shong

    2016-12-06

    Acrolein (Acr) is a potent cytotoxic and DNA damaging agent which is ubiquitous in the environment and abundant in tobacco smoke. Acr is also an active cytotoxic metabolite of the anti-cancer drugs cyclophosphamide and ifosfamide. The mechanisms via which Acr exerts its anti-cancer activity and cytotoxicity are not clear. In this study, we found that Acr induces cytotoxicity and cell death in human cancer cells with different activities of p53. Acr preferentially binds nucleolar ribosomal DNA (rDNA) to form Acr-deoxyguanosine adducts, and induces oxidative damage to both rDNA and ribosomal RNA (rRNA). Acr triggers ribosomal stress responses, inhibits rRNA synthesis, reduces RNA polymerase I binding to the promoter of rRNA gene, disrupts nucleolar integrity, and impairs ribosome biogenesis and polysome formation. Acr causes an increase in MDM2 levels and phosphorylation of MDM2 in A549 and HeLa cells which are p53 active and p53 inactive, respectively. It enhances the binding of ribosomal protein RPL11 to MDM2 and reduces the binding of p53 and E2F-1 to MDM2 resulting in stabilization/activation of p53 in A549 cells and degradation of E2F-1 in A549 and HeLa cells. We propose that Acr induces ribosomal stress which leads to activation of MDM2 and RPL11-MDM2 binding, consequently, activates p53 and enhances E2F-1 degradation, and that taken together these two processes induce apoptosis and cell death.

  18. Beta-arrestin inhibits CAMKKbeta-dependent AMPK activation downstream of protease-activated-receptor-2.

    PubMed

    Wang, Ping; Jiang, Yong; Wang, Yinsheng; Shyy, John Y; DeFea, Kathryn A

    2010-09-21

    Proteinase-activated-receptor-2 (PAR2) is a seven transmembrane receptor that can activate two separate signaling arms: one through Gαq and Ca2+ mobilization, and a second through recruitment of β-arrestin scaffolds. In some cases downstream targets of the Gαq/Ca2+ signaling arm are directly inhibited by β-arrestins, while in other cases the two pathways are synergistic; thus β-arrestins act as molecular switches capable of modifying the signal generated by the receptor. Here we demonstrate that PAR2 can activate adenosine monophosphate-activated protein kinase (AMPK), a key regulator of cellular energy balance, through Ca2+-dependent Kinase Kinase β (CAMKKβ), while inhibiting AMPK through interaction with β-arrestins. The ultimate outcome of PAR2 activation depended on the cell type studied; in cultured fibroblasts with low endogenous β-arrestins, PAR2 activated AMPK; however, in primary fat and liver, PAR2 only activated AMPK in β-arrestin-2-/- mice. β-arrestin-2 could be co-immunoprecipitated with AMPK and CAMKKβ under baseline conditions from both cultured fibroblasts and primary fat, and its association with both proteins was increased by PAR2 activation. Addition of recombinant β-arrestin-2 to in vitro kinase assays directly inhibited phosphorylation of AMPK by CAMKKβ on Thr172. Studies have shown that decreased AMPK activity is associated with obesity and Type II Diabetes, while AMPK activity is increased with metabolically favorable conditions and cholesterol lowering drugs. These results suggest a role for β-arrestin in the inhibition of AMPK signaling, raising the possibility that β-arrestin-dependent PAR2 signaling may act as a molecular switch turning a positive signal to AMPK into an inhibitory one.

  19. Dimethyl sulfoxide inhibits NLRP3 inflammasome activation.

    PubMed

    Ahn, Huijeong; Kim, Jeeyoung; Jeung, Eui-Bae; Lee, Geun-Shik

    2014-04-01

    Dimethyl sulfoxide (DMSO) is an amphipathic molecule that is commonly/widely used as a solvent for biological compounds. In addition, DMSO has been studied as a medication for the treatment of inflammation, cystitis, and arthritis. Based on the anti-inflammatory characteristics of DMSO, we elucidated the effects of DMSO on activation of inflammasomes, which are cytoplasmic multi-protein complexes that mediate the maturation of interleukin (IL)-1β by activating caspase-1 (Casp1). In the present study, we prove that DMSO attenuated IL-1β maturation, Casp1 activity, and ASC pyroptosome formation via NLRP3 inflammasome activators. Further, NLRC4 and AIM2 inflammasome activity were not affected, suggesting that DMSO is a selective inhibitor of the NLRP3 inflammasomes. The anti-inflammatory effect of DMSO was further confirmed in animal, LPS-endotoxin sepsis and inflammatory bowel disease models. In addition, DMSO inhibited LPS-mediating IL-1s transcription. Taken together, DMSO shows anti-inflammatory characteristics, attenuates NLRP3 inflammasome activation, and mediates inhibition of IL-1s transcription. Crown Copyright © 2013. Published by Elsevier GmbH. All rights reserved.

  20. Isothiocyanates: cholinesterase inhibiting, antioxidant, and anti-inflammatory activity.

    PubMed

    Burčul, Franko; Generalić Mekinić, Ivana; Radan, Mila; Rollin, Patrick; Blažević, Ivica

    2018-12-01

    Finding a new type of cholinesterase inhibitor that would overcome the brain availability and pharmacokinetic parameters or hepatotoxic liability has been a focus of investigations dealing with the treatment of Alzheimer's disease. Isothiocyanates have not been previously investigated as potential cholinesterase inhibitors. These compounds can be naturally produced from their glucosinolate precursors, secondary metabolites widely distributed in our daily Brassica vegetables. Among 11 tested compounds, phenyl isothiocyanate and its derivatives showed the most promising inhibitory activity. 2-Methoxyphenyl ITC showed best inhibition on acetylcholinesterase with IC 50 of 0.57 mM, while 3-methoxyphenyl ITC showed the best inhibition on butyrylcholinesterase having 49.2% at 1.14 mM. Assessment of the antioxidant efficacy using different methods led to a similar conclusion. The anti-inflammatory activity was also tested using human COX-2 enzyme, ranking phenyl isothiocyanate, and 3-methoxyphenyl isothiocyanate as most active, with ∼99% inhibition at 50 μM.

  1. Aversive Learning and Appetitive Motivation Toggle Feed-Forward Inhibition in the Drosophila Mushroom Body.

    PubMed

    Perisse, Emmanuel; Owald, David; Barnstedt, Oliver; Talbot, Clifford B; Huetteroth, Wolf; Waddell, Scott

    2016-06-01

    In Drosophila, negatively reinforcing dopaminergic neurons also provide the inhibitory control of satiety over appetitive memory expression. Here we show that aversive learning causes a persistent depression of the conditioned odor drive to two downstream feed-forward inhibitory GABAergic interneurons of the mushroom body, called MVP2, or mushroom body output neuron (MBON)-γ1pedc>α/β. However, MVP2 neuron output is only essential for expression of short-term aversive memory. Stimulating MVP2 neurons preferentially inhibits the odor-evoked activity of avoidance-directing MBONs and odor-driven avoidance behavior, whereas their inhibition enhances odor avoidance. In contrast, odor-evoked activity of MVP2 neurons is elevated in hungry flies, and their feed-forward inhibition is required for expression of appetitive memory at all times. Moreover, imposing MVP2 activity promotes inappropriate appetitive memory expression in food-satiated flies. Aversive learning and appetitive motivation therefore toggle alternate modes of a common feed-forward inhibitory MVP2 pathway to promote conditioned odor avoidance or approach. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

  2. An Activation/Inhibition Network Cell.

    DTIC Science & Technology

    1982-01-01

    memory is a powerful concept, no one has found a way of doing activation and inhibition on it, so I’ll stick to the simple mapping. --------- AAB -W...Rumongus Scale Integration.. G-9- Vorking Paper 31 Referens. Fahiman, S.. NL: A s=u LI= rpnng A" using rial-world kowledge . MIT Pess, Cambridge, 1979

  3. Fatty acid synthase inhibition activates AMP-activated protein kinase in SKOV3 human ovarian cancer cells.

    PubMed

    Zhou, Weibo; Han, Wan Fang; Landree, Leslie E; Thupari, Jagan N; Pinn, Michael L; Bililign, Tsion; Kim, Eun Kyoung; Vadlamudi, Aravinda; Medghalchi, Susan M; El Meskini, Rajaa; Ronnett, Gabriele V; Townsend, Craig A; Kuhajda, Francis P

    2007-04-01

    Fatty acid synthase (FAS), the enzyme responsible for the de novo synthesis of fatty acids, is highly expressed in ovarian cancers and most common human carcinomas. Inhibition of FAS and activation of AMP-activated protein kinase (AMPK) have been shown to be cytotoxic to human cancer cells in vitro and in vivo. In this report, we explore the cytotoxic mechanism of action of FAS inhibition and show that C93, a synthetic FAS inhibitor, increases the AMP/ATP ratio, activating AMPK in SKOV3 human ovarian cancer cells, which leads to cytotoxicity. As a physiologic consequence of AMPK activation, acetyl-CoA carboxylase (ACC), the rate-limiting enzyme of fatty acid synthesis, was phosphorylated and inhibited whereas glucose oxidation was increased. Despite these attempts to conserve energy, the AMP/ATP ratio increased with worsening cellular redox status. Pretreatment of SKOV3 cells with compound C, an AMPK inhibitor, substantially rescued the cells from C93 cytotoxicity, indicating its dependence on AMPK activation. 5-(Tetradecyloxy)-2-furoic acid, an ACC inhibitor, did not activate AMPK despite inhibiting fatty acid synthesis pathway activity and was not significantly cytotoxic to SKOV3 cells. This indicates that substrate accumulation from FAS inhibition triggering AMPK activation, not end-product depletion of fatty acids, is likely responsible for AMPK activation. C93 also exhibited significant antitumor activity and apoptosis against SKOV3 xenografts in athymic mice without significant weight loss or cytotoxicity to proliferating cellular compartments such as bone marrow, gastrointestinal tract, or skin. Thus, pharmacologic FAS inhibition selectively activates AMPK in ovarian cancer cells, inducing cytotoxicity while sparing most normal human tissues from the pleiotropic effects of AMPK activation.

  4. Post-learning hippocampal dynamics promote preferential retention of rewarding events

    PubMed Central

    Gruber, Matthias J.; Ritchey, Maureen; Wang, Shao-Fang; Doss, Manoj K.; Ranganath, Charan

    2016-01-01

    Reward motivation is known to modulate memory encoding, and this effect depends on interactions between the substantia nigra/ ventral tegmental area complex (SN/VTA) and the hippocampus. It is unknown, however, whether these interactions influence offline neural activity in the human brain that is thought to promote memory consolidation. Here, we used functional magnetic resonance imaging (fMRI) to test the effect of reward motivation on post-learning neural dynamics and subsequent memory for objects that were learned in high- or low-reward motivation contexts. We found that post-learning increases in resting-state functional connectivity between the SN/VTA and hippocampus predicted preferential retention of objects that were learned in high-reward contexts. In addition, multivariate pattern classification revealed that hippocampal representations of high-reward contexts were preferentially reactivated during post-learning rest, and the number of hippocampal reactivations was predictive of preferential retention of items learned in high-reward contexts. These findings indicate that reward motivation alters offline post-learning dynamics between the SN/VTA and hippocampus, providing novel evidence for a potential mechanism by which reward could influence memory consolidation. PMID:26875624

  5. Mutant p53 protein localized in the cytoplasm inhibits autophagy.

    PubMed

    Morselli, Eugenia; Tasdemir, Ezgi; Maiuri, Maria Chiara; Galluzzi, Lorenzo; Kepp, Oliver; Criollo, Alfredo; Vicencio, José Miguel; Soussi, Thierry; Kroemer, Guido

    2008-10-01

    The knockout, knockdown or chemical inhibition of p53 stimulates autophagy. Moreover, autophagy-inducing stimuli such as nutrient depletion, rapamycin or lithium cause the depletion of cytoplasmic p53, which in turn is required for the induction of autophagy. Here, we show that retransfection of p53(-/-) HCT 116 colon carcinoma cells with wild type p53 decreases autophagy down to baseline levels. Surprisingly, one third among a panel of 22 cancer-associated p53 single amino acid mutants also inhibited autophagy when transfected into p53(-/-) cells. Those variants of p53 that preferentially localize to the cytoplasm effectively repressed autophagy, whereas p53 mutants that display a prominently nuclear distribution failed to inhibit autophagy. The investigation of a series of deletion mutants revealed that removal of the DNA-binding domain from p53 fails to interfere with its role in the regulation of autophagy. Altogether, these results identify the cytoplasmic localization of p53 as the most important feature for p53-mediated autophagy inhibition. Moreover, the structural requirements for the two biological activities of extranuclear p53, namely induction of apoptosis and inhibition of autophagy, are manifestly different.

  6. Modulation of T Cell Activation by Malignant Melanoma Initiating Cells

    PubMed Central

    Schatton, Tobias; Schütte, Ute; Frank, Natasha Y.; Zhan, Qian; Hoerning, André; Robles, Susanne C.; Zhou, Jun; Hodi, F. Stephen; Spagnoli, Giulio C.; Murphy, George F.; Frank, Markus H.

    2010-01-01

    Highly immunogenic cancers such as malignant melanoma are capable of inexorable tumor growth despite the presence of antitumor immunity. This raises the possibility that only a restricted minority of tumorigenic malignant cells might possess the phenotypic and functional characteristics to modulate tumor-directed immune activation. Here we provide evidence supporting this hypothesis, by demonstrating that tumorigenic ABCB5+ malignant melanoma-initiating cells (MMICs) possess the capacity to preferentially inhibit interleukin (IL)-2-dependent T cell activation and to support, in a B7.2-dependent manner, regulatory T (Treg) cell induction. Compared to melanoma bulk populations, ABCB5+ MMICs expressed lower levels of the major histocompatibility complex (MHC) class I, showed aberrant positivity for MHC class II, and exhibited lower expression levels of the melanoma-associated antigens (MAAs) MART-1, ML-IAP, NY-ESO-1, and MAGE-A. In addition, tumorigenic ABCB5+ subpopulations preferentially expressed the costimulatory molecules B7.2 and PD-1 in both established melanoma xenografts and clinical tumor specimens in vivo. In immune activation assays, ABCB5+ melanoma cells inhibited mitogen-dependent human peripheral blood mononuclear cell (PBMC) proliferation and IL-2 production more efficiently than ABCB5− populations. Moreover, coculture with ABCB5+ MMICs increased, in a B7.2 signalling-dependent manner, CD4+CD25+FoxP3+ Treg cell abundance and IL-10 production by mitogen-activated PBMCs. Consistent with these findings, ABCB5+ melanoma subsets also preferentially inhibited IL-2 production and induced IL-10 secretion by cocultured patient-derived, syngeneic PBMCs. Our findings identify novel T cell-modulatory functions of ABCB5+ melanoma subpopulations and suggest specific roles for MMICs in the evasion of antitumor immunity and in cancer immunotherapeutic resistance. PMID:20068175

  7. Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides

    PubMed Central

    Borbiro, Istvan; Badheka, Doreen; Rohacs, Tibor

    2015-01-01

    Capsaicin is an activator of the heat-sensitive TRPV1 (transient receptor potential vanilloid 1) ion channels and has been used as a local analgesic. We found that activation of TRPV1 channels with capsaicin either in dorsal root ganglion neurons or in a heterologous expression system inhibited the mechanosensitive Piezo1 and Piezo2 channels by depleting phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and its precursor PI(4)P from the plasma membrane through Ca2+-induced phospholipase Cδ (PLCδ) activation. Experiments with chemically inducible phosphoinositide phosphatases and receptor-induced activation of PLCβ indicated that inhibition of Piezo channels required depletion of both PI(4)P and PI(4,5)P2. The mechanically activated current amplitudes decreased substantially in the excised inside-out configuration, where the membrane patch containing Piezo1 channels is removed from the cell. PI(4,5)P2 and PI(4)P applied to these excised patches inhibited this decrease. Thus, we concluded that Piezo channel activity requires the presence of phosphoinositides, and the combined depletion of PI(4,5)P2 or PI(4)P reduces channel activity. In addition to revealing a role for distinct membrane lipids in mechanosensitive ion channel regulation, these data suggest that inhibition of Piezo2 channels may contribute to the analgesic effect of capsaicin. PMID:25670203

  8. Conceptualization of preferential flow for hillslope stability assessment

    NASA Astrophysics Data System (ADS)

    Kukemilks, Karlis; Wagner, Jean-Frank; Saks, Tomas; Brunner, Philip

    2018-03-01

    This study uses two approaches to conceptualize preferential flow with the goal to investigate their influence on hillslope stability. Synthetic three-dimensional hydrogeological models using dual-permeability and discrete-fracture conceptualization were subsequently integrated into slope stability simulations. The slope stability simulations reveal significant differences in slope stability depending on the preferential flow conceptualization applied, despite similar small-scale hydrogeological responses of the system. This can be explained by a local-scale increase of pore-water pressures observed in the scenario with discrete fractures. The study illustrates the critical importance of correctly conceptualizing preferential flow for slope stability simulations. It further demonstrates that the combination of the latest generation of physically based hydrogeological models with slope stability simulations allows for improvement to current modeling approaches through more complex consideration of preferential flow paths.

  9. Preparation of optically active (2RS,3SR)-2-amino-3-hydroxy-3-phenylpropanoic acid (threo-beta-phenylserine) via optical resolutions by replacing and preferential crystallization.

    PubMed

    Shiraiwa, Tadashi; Kawashima, Yuka; Ikaritani, Atsushi; Suganuma, Yumiko; Saijoh, Reiichi

    2006-08-01

    To obtain optically active threo-2-amino-3-hydroxy-3-phenylpropanoic acid (1) via optical resolutions by replacing and preferential crystallization, the racemic structure of (2RS,3SR)-1 hydrochloride [(2RS,3SR)-1.HCl] was examined based on the melting point, solubility, and infrared spectrum. (2RS,3SR)-1.HCl was indicated to exist as a conglomerate at room temperature, although it forms a racemic compound at the melting point. When, in optical resolution by replacing crystallization, L-phenylalanine methyl ester hydrochloride (L-2) was used as the optically active co-solute, (2R,3S)-1.HCl was preferentially crystallized from the supersaturated racemic solution; the use of D-2 as the co-solute afforded (2S,3R)-1.HCl with an optical purity of 95%. In addition, optical resolution by preferential crystallization was successfully achieved to give successively (2R,3S)- and (2S,3R)-1.HCl with optical purities of 90-92%. The (2R,3S)- and (2S,3R)-1.HCl purified by recrystallization from 1-propanol were treated with triethylamine in methanol to give optically pure (2R,3S)- and (2S,3R)-1.

  10. Functional hierarchy underlies preferential connectivity disturbances in schizophrenia.

    PubMed

    Yang, Genevieve J; Murray, John D; Wang, Xiao-Jing; Glahn, David C; Pearlson, Godfrey D; Repovs, Grega; Krystal, John H; Anticevic, Alan

    2016-01-12

    Schizophrenia may involve an elevated excitation/inhibition (E/I) ratio in cortical microcircuits. It remains unknown how this regulatory disturbance maps onto neuroimaging findings. To address this issue, we implemented E/I perturbations within a neural model of large-scale functional connectivity, which predicted hyperconnectivity following E/I elevation. To test predictions, we examined resting-state functional MRI in 161 schizophrenia patients and 164 healthy subjects. As predicted, patients exhibited elevated functional connectivity that correlated with symptom levels, and was most prominent in association cortices, such as the fronto-parietal control network. This pattern was absent in patients with bipolar disorder (n = 73). To account for the pattern observed in schizophrenia, we integrated neurobiologically plausible, hierarchical differences in association vs. sensory recurrent neuronal dynamics into our model. This in silico architecture revealed preferential vulnerability of association networks to E/I imbalance, which we verified empirically. Reported effects implicate widespread microcircuit E/I imbalance as a parsimonious mechanism for emergent inhomogeneous dysconnectivity in schizophrenia.

  11. Functional hierarchy underlies preferential connectivity disturbances in schizophrenia

    PubMed Central

    Yang, Genevieve J.; Murray, John D.; Wang, Xiao-Jing; Glahn, David C.; Pearlson, Godfrey D.; Repovs, Grega; Krystal, John H.; Anticevic, Alan

    2016-01-01

    Schizophrenia may involve an elevated excitation/inhibition (E/I) ratio in cortical microcircuits. It remains unknown how this regulatory disturbance maps onto neuroimaging findings. To address this issue, we implemented E/I perturbations within a neural model of large-scale functional connectivity, which predicted hyperconnectivity following E/I elevation. To test predictions, we examined resting-state functional MRI in 161 schizophrenia patients and 164 healthy subjects. As predicted, patients exhibited elevated functional connectivity that correlated with symptom levels, and was most prominent in association cortices, such as the fronto-parietal control network. This pattern was absent in patients with bipolar disorder (n = 73). To account for the pattern observed in schizophrenia, we integrated neurobiologically plausible, hierarchical differences in association vs. sensory recurrent neuronal dynamics into our model. This in silico architecture revealed preferential vulnerability of association networks to E/I imbalance, which we verified empirically. Reported effects implicate widespread microcircuit E/I imbalance as a parsimonious mechanism for emergent inhomogeneous dysconnectivity in schizophrenia. PMID:26699491

  12. Obligate intracellular bacterium Ehrlichia inhibiting mitochondrial activity

    PubMed Central

    Liu, Yan; Zhang, Zhikai; Jiang, Yongquan; Zhang, Lihong; Popov, Vsevolod L.; Zhang, Jianzhi; Walker, David H.; Yu, Xue-jie

    2010-01-01

    Ehrlichia are obligately intracellular bacteria that reside in a vacuole in the cytoplasm of phagocytes. We determined by confocal microscopy the interaction between Ehrlichia and mitochondria in DH82 cells to investigate the mechanism of Ehrlichia survival inside the phagocyte. The most remarkable finding of our study was that Ehrlichia morulae interacted with mitochondria and inhibited mitochondrial metabolism,. We showed that in E. chaffeensis-infected DH82 cells, mitochondria did not incorporate BrdU and transcriptional level of the mitochondrial gene NADPH2 was significantly reduced, indicating the inhibition of mitochondrial metabolism. This study demonstrates that Ehrlichia are able to inhibit mitochondrial activities, and it opens up a new avenue for the study of Ehrlichia pathogenesis. PMID:21070861

  13. Gastric acid secretion: activation and inhibition.

    PubMed Central

    Sachs, G.; Prinz, C.; Loo, D.; Bamberg, K.; Besancon, M.; Shin, J. M.

    1994-01-01

    Peripheral regulation of gastric acid secretion is initiated by the release of gastrin from the G cell. Gastrin then stimulates the cholecystokinin-B receptor on the enterochromaffin-like cell beginning a calcium signaling cascade. An exocytotic release of histamine follows with concomitant activation of a C1- current. The released histamine begins the H2-receptor mediated sequence of events in the parietal cell, which results in activation of the gastric H+/K+ - ATPase. This enzyme is the final common pathway of acid secretion. The H+/K+ - ATPase is composed of two subunits: the larger alpha-subunit couples ion transport to hydrolysis of ATP, the smaller beta-subunit is required for appropriate assembly of the holoenzyme. Both the membrane and extracytoplasmic domain contain the ion transport pathway, and therefore, this region is the target for the antisecretory drugs of the post-H2 era. The 100 kDa alpha-subunit has probably 10 membrane spanning segments with, therefore, five extracytoplasmic loops. The 35 kDA beta-subunit has a single membrane spanning segment, and most of this protein is extracytoplasmic with the six or seven N glycosylation consensus sequences occupied. Omeprazole is an acid-accumulated, acid-activated, prodrug that binds covalently to two cysteine residues at positions 813 (or 822) and 892, accessible from the acidic face of the pump. Lansoprazole binds to cys321, 813 (or 822) and 892; pantoprazole binds to cys813 and 822. The common binding site for these drugs (cys813 or 822) is responsible for the inhibition of acid transport. Covalent inhibition of the acid pump improves control of acid secretion, but since the effective half life of the inhibition in man is about 48 hr, full inhibition of acid secretion, perhaps necessary for eradication of Helicobacter pylori in combination with a single antibiotic, will require prolongation of the effect of this class of drug. PMID:7502535

  14. Aspirin inhibits human telomerase activation in unstable carotid plaques

    PubMed Central

    LI, FANGMING; GUO, YI; JIANG, XIN; ZHONG, JIANXIN; LI, GUANDONG; SUN, SHENGGANG

    2013-01-01

    The activation of telomerase in unstable plaques is an important factor in atherosclerosis, and may be predictive of the risk of cerebrovascular diseases. Human telomerase reverse transcriptase (hTERT) is a subunit of telomerase that is essential for telomerase activation. The aim of the present study was to investigate whether aspirin inhibits the activation of telomerase and hTERT in unstable carotid plaques. Polymorphonuclear neutrophils (PMNs) derived from carotid plaques were isolated from the washing medium of angioplasty balloons, while circulating PMNs, isolated from arterial blood, served as the controls. A polymerase chain reaction-based telomeric repeat amplification protocol (TRAP) enzyme-linked immunosorbent assay (ELISA) was used to measure the telomerase activity in the cells following treatment with aspirin. The mRNA and protein expression of hTERT were detected by a reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis, respectively. The results revealed that the atherosclerotic plaques were positive for telomerase activity, and that aspirin inhibited the telomerase activity of the PMNs derived from the plaques. In addition, aspirin was demonstrated to inhibit the mRNA and protein expression of hTERT through the suppression of hTERT transcriptional activity; however, it had no inhibitory effect on the telomerase activity of the circulating PMNs. Thus, the activation of telomerase in resident PMNs is critical in the instability of carotid plaques. The upregulation of telomerase and hTERT during the progression of atherosclerosis may indicate a role for telomerase in the vascular remodeling that occurs during atherogenesis. Aspirin was demonstrated to inhibit the activation of telomerase via an hTERT-dependent manner in the PMN cells of unstable carotid plaques, and thus hTERT may be considered as a target in the treatment of cerebrovascular diseases. PMID:23935747

  15. Aspergillus ficuum phytase activity is inhibited by cereal grain components.

    PubMed

    Bekalu, Zelalem Eshetu; Madsen, Claus Krogh; Dionisio, Giuseppe; Brinch-Pedersen, Henrik

    2017-01-01

    In the current study, we report for the first time that grain components of barley, rice, wheat and maize can inhibit the activity of Aspergillus ficuum phytase. The phytase inhibition is dose dependent and varies significantly between cereal species, between cultivars of barley and cultivars of wheat and between Fusarium graminearum infected and non-infected wheat grains. The highest endpoint level of phytase activity inhibition was 90%, observed with grain protein extracts (GPE) from F. graminearum infected wheat. Wheat GPE from grains infected with F. graminearum inhibits phytase activity significantly more than GPE from non-infected grains. For four barley cultivars studied, the IC50 value ranged from 0.978 ± 0.271 to 3.616 ± 0.087 mg×ml-1. For two non-infected wheat cultivars investigated, the IC50 values were varying from 2.478 ± 0.114 to 3.038 ± 0.097 mg×ml-1. The maize and rice cultivars tested gaveIC50 values on 0.983 ± 0.205 and 1.972 ± 0.019 mg×ml-1, respectively. After purifying the inhibitor from barley grains via Superdex G200, an approximately 30-35 kDa protein was identified. No clear trend for the mechanism of inhibition could be identified via Michaelis-Menten kinetics and Lineweaver-Burk plots. However, testing of the purified phytase inhibitor together with the A. ficuum phytase and the specific protease inhibitors pepstatin A, E64, EDTA and PMSF revealed that pepstatin A repealed the phytase inhibition. This indicates that the observed inhibition of A. ficuum phytase by cereal grain extracts is caused by protease activity of the aspartic proteinase type.

  16. Aspergillus ficuum phytase activity is inhibited by cereal grain components

    PubMed Central

    Bekalu, Zelalem Eshetu; Madsen, Claus Krogh; Dionisio, Giuseppe

    2017-01-01

    In the current study, we report for the first time that grain components of barley, rice, wheat and maize can inhibit the activity of Aspergillus ficuum phytase. The phytase inhibition is dose dependent and varies significantly between cereal species, between cultivars of barley and cultivars of wheat and between Fusarium graminearum infected and non-infected wheat grains. The highest endpoint level of phytase activity inhibition was 90%, observed with grain protein extracts (GPE) from F. graminearum infected wheat. Wheat GPE from grains infected with F. graminearum inhibits phytase activity significantly more than GPE from non-infected grains. For four barley cultivars studied, the IC50 value ranged from 0.978 ± 0.271 to 3.616 ± 0.087 mg×ml-1. For two non-infected wheat cultivars investigated, the IC50 values were varying from 2.478 ± 0.114 to 3.038 ± 0.097 mg×ml-1. The maize and rice cultivars tested gaveIC50 values on 0.983 ± 0.205 and 1.972 ± 0.019 mg×ml-1, respectively. After purifying the inhibitor from barley grains via Superdex G200, an approximately 30–35 kDa protein was identified. No clear trend for the mechanism of inhibition could be identified via Michaelis-Menten kinetics and Lineweaver-Burk plots. However, testing of the purified phytase inhibitor together with the A. ficuum phytase and the specific protease inhibitors pepstatin A, E64, EDTA and PMSF revealed that pepstatin A repealed the phytase inhibition. This indicates that the observed inhibition of A. ficuum phytase by cereal grain extracts is caused by protease activity of the aspartic proteinase type. PMID:28472144

  17. Class IA PI3K inhibition inhibits cell growth and proliferation in mantle cell lymphoma.

    PubMed

    Tabe, Yoko; Jin, Linhua; Konopleva, Marina; Shikami, Masato; Kimura, Shinya; Andreeff, Michael; Raffeld, Mark; Miida, Takashi

    2014-01-01

    Constitutive activation of the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin signaling pathway preferentially occurs in aggressive blastoid variants of mantle cell lymphoma (MCL) and is implicated in the pathogenesis of this disease. In this study, we investigated the role of PI3K isoforms on proliferation of aggressive MCL cells. The changes in cell viability, cell cycle distribution and apoptosis induction by the PI3K isoform-selective inhibitors were evaluated. The molecular basis underlying the effects of the specific inhibition of PI3K isoforms was investigated by Western blot analysis. Our results demonstrated that a class IA PI3K isoform is most commonly involved in the constitutive activation of Akt in aggressive MCL. Treatment with a p110α isoform-specific inhibitor induced prominent cell cycle arrest followed by apoptosis through complete abolishment of phosphorylated (p)-Akt and its downstream targets. An inhibitor of isoform p110δ induced moderate cell cycle arrest with downregulation of p-Akt and p-S6K. A dual inhibitor of p110α and p110δ GDC-0941 caused more prominent cell growth inhibition compared to selective p110α or p110δ inhibitors. Inhibition of the class IB PI3K isoform p110γ did not cause cell cycle arrest or induce apoptosis in MCL cells. These findings suggest that the therapeutic ablation of class IA PI3K may be a promising strategy for the treatment of refractory, aggressive MCL. Copyright © 2013 S. Karger AG, Basel.

  18. Production of monoclonal antibody inhibiting dipeptidylaminopeptidase IV activity of Porphyromonas gingivalis.

    PubMed

    Teshirogi, K; Hayakawa, M; Ikemi, T; Abiko, Y

    2003-06-01

    Porphyromonas gingivalis is a Gram-negative anaerobic bacterial species implicated as an important pathogen in the development of adult periodontitis. We previously cloned a gene encoding dipeptydilaminopeptidase IV (DAPIV) from P. gingivalis. In the present study, for immunological diagnosis and development of passive immunization, we produced a mouse monoclonal antibody (MAb) capable of inhibiting the DAPIV activity of P. gingivalis using highly purified recombinant DAPIV as an immunogen. The constructed MAb, designated as MAb-Pg-DAP-1, significantly inhibited DAPIV activity in P. gingivalis, as well as slightly inhibited that in other gram-negative bacteria such as Porphyromonas endodontalis and Prevotella loesheii, whereas no inhibition was seen in the gram-positive bacteria Streptococcus mutans and Actinomyces viscosus. Furthermore, the MAb did not inhibit DAPIV enzyme activity in human serum. This novel MAb may be useful for the development of immunological diagnosis capability and in passive immunization.

  19. Differential inhibition of N and P/Q Ca2+ currents by 5-HT1A and 5-HT1D receptors in spinal neurons of Xenopus larvae

    PubMed Central

    Sun, Qian-Quan; Dale, Nicholas

    1998-01-01

    In whole-cell patch clamp recordings made from non-sensory neurons acutely isolated from the spinal cord of Xenopus (stage 40–42) larvae, two forms of inhibition of the high voltage-activated (HVA) Ca2+ currents were produced by 5-HT. One was voltage dependent and associated with both slowing of the activation kinetics and shifting of the voltage dependence of the HVA currents. This inhibition was relieved by strong depolarizing prepulses. A second form of inhibition was neither associated with slowing of the activation kinetics nor relieved by depolarizing prepulses and was thus voltage independent. In all neurons examined, 5-HT (1 μM) reversibly reduced 34 ± 1.6 % (n = 102) of the HVA Ca2+ currents. In about 40 % of neurons, the inhibition was totally voltage independent. In another 5 %, the inhibition was totally voltage dependent. In the remaining neurons, inhibition was only partially (by around 40 %) relieved by a large depolarizing prepulse, suggesting that in these, the inhibition consisted of both voltage-dependent and -independent components. By using selective channel blockers, we found that 5-HT acted on both N- and P/Q-type channels. However, whereas the inhibition of P/Q-type currents was only voltage independent, the inhibition of N-type currents had both voltage-dependent and -independent components. The effects of 5-HT on HVA Ca2+ currents were mediated by 5-HT1A and 5-HT1D receptors. The 5-HT1A receptors not only preferentially caused voltage-independent inhibition, but did so by acting mainly on the ω-agatoxin-IVA-sensitive Ca2+ channels. In contrast, the 5-HT1D receptor produced both voltage-dependent and -independent inhibition and was preferentially coupled to ω-conotoxin-GVIA sensitive channels. This complexity of modulation may allow fine tuning of transmitter release and calcium signalling in the spinal circuitry of Xenopus larvae. PMID:9625870

  20. Discovering Preferential Patterns in Sectoral Trade Networks.

    PubMed

    Cingolani, Isabella; Piccardi, Carlo; Tajoli, Lucia

    2015-01-01

    We analyze the patterns of import/export bilateral relations, with the aim of assessing the relevance and shape of "preferentiality" in countries' trade decisions. Preferentiality here is defined as the tendency to concentrate trade on one or few partners. With this purpose, we adopt a systemic approach through the use of the tools of complex network analysis. In particular, we apply a pattern detection approach based on community and pseudocommunity analysis, in order to highlight the groups of countries within which most of members' trade occur. The method is applied to two intra-industry trade networks consisting of 221 countries, relative to the low-tech "Textiles and Textile Articles" and the high-tech "Electronics" sectors for the year 2006, to look at the structure of world trade before the start of the international financial crisis. It turns out that the two networks display some similarities and some differences in preferential trade patterns: they both include few significant communities that define narrow sets of countries trading with each other as preferential destinations markets or supply sources, and they are characterized by the presence of similar hierarchical structures, led by the largest economies. But there are also distinctive features due to the characteristics of the industries examined, in which the organization of production and the destination markets are different. Overall, the extent of preferentiality and partner selection at the sector level confirm the relevance of international trade costs still today, inducing countries to seek the highest efficiency in their trade patterns.

  1. Preferential flow from pore to landscape scales

    NASA Astrophysics Data System (ADS)

    Koestel, J. K.; Jarvis, N.; Larsbo, M.

    2017-12-01

    In this presentation, we give a brief personal overview of some recent progress in quantifying preferential flow in the vadose zone, based on our own work and those of other researchers. One key challenge is to bridge the gap between the scales at which preferential flow occurs (i.e. pore to Darcy scales) and the scales of interest for management (i.e. fields, catchments, regions). We present results of recent studies that exemplify the potential of 3-D non-invasive imaging techniques to visualize and quantify flow processes at the pore scale. These studies should lead to a better understanding of how the topology of macropore networks control key state variables like matric potential and thus the strength of preferential flow under variable initial and boundary conditions. Extrapolation of this process knowledge to larger scales will remain difficult, since measurement technologies to quantify macropore networks at these larger scales are lacking. Recent work suggests that the application of key concepts from percolation theory could be useful in this context. Investigation of the larger Darcy-scale heterogeneities that generate preferential flow patterns at the soil profile, hillslope and field scales has been facilitated by hydro-geophysical measurement techniques that produce highly spatially and temporally resolved data. At larger regional and global scales, improved methods of data-mining and analyses of large datasets (machine learning) may help to parameterize models as well as lead to new insights into the relationships between soil susceptibility to preferential flow and site attributes (climate, land uses, soil types).

  2. The SARS coronavirus papain like protease can inhibit IRF3 at a post activation step that requires deubiquitination activity.

    PubMed

    Matthews, Krystal; Schäfer, Alexandra; Pham, Alissa; Frieman, Matthew

    2014-12-07

    The outcome of a viral infection is regulated by complex interactions of viral and host factors. SARS coronavirus (SARS-CoV) engages and regulates several innate immune response pathways during infection. We have previously shown that the SARS-CoV Papain-like Protease (PLpro) inhibits type I interferon (IFN) by inhibiting IRF3 phosphorylation thereby blocking downstream Interferon induction. This finding prompted us to identify other potential mechanisms of inhibition of PLpro on IFN induction. We have used plasmids expressing PLpro and IRF3 including an IRF3 mutant that is constitutively active, called IRF3(5D). In these experiments we utilize transfections, chromatin immunoprecipitation, Electro-mobility Shift Assays (EMSA) and protein localization to identify where IRF3 and IRF3(5D) are inhibited by PLpro. Here we show that PLpro also inhibits IRF3 activation at a step after phosphorylation and that this inhibition is dependent on the de-ubiquitination (DUB) activity of PLpro. We found that PLpro is able to block the type I IFN induction of a constitutively active IRF3, but does not inhibit IRF3 dimerization, nuclear localization or DNA binding. However, inhibition of PLpro's DUB activity by mutagenesis blocked the IRF3 inhibition activity of PLpro, suggesting a role for IRF3 ubiquitination in induction of a type I IFN innate immune response. These results demonstrate an additional mechanism that PLpro is able to inhibit IRF3 signaling. These data suggest novel innate immune antagonism activities of PLpro that may contribute to SARS-CoV pathogenesis.

  3. Inhibition of transcriptional activity of c-JUN by SIRT1

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gao Zhanguo; Ye Jianping

    2008-11-28

    c-JUN is a major component of heterodimer transcription factor AP-1 (Activator Protein-1) that activates gene transcription in cell proliferation, inflammation and stress responses. SIRT1 (Sirtuin 1) is a histone deacetylase that controls gene transcription through modification of chromatin structure. However, it is not clear if SIRT1 regulates c-JUN activity in the control of gene transcription. Here, we show that SIRT1 associated with c-JUN in co-immunoprecipitation of whole cell lysate, and inhibited the transcriptional activity of c-JUN in the mammalian two hybridization system. SIRT1 was found in the AP-1 response element in the matrix metalloproteinase-9 (MMP9) promoter DNA leading to inhibitionmore » of histone 3 acetylation as shown in a ChIP assay. The SIRT1 signal was reduced by the AP-1 activator PMA, and induced by the SIRT1 activator Resveratrol in the promoter DNA. SIRT1-mediaetd inhibition of AP-1 was demonstrated in the MMP9 gene expression at the gene promoter, mRNA and protein levels. In mouse embryonic fibroblast (MEF) with SIRT1 deficiency (SIRT1{sup -/-}), mRNA and protein of MMP9 were increased in the basal condition, and the inhibitory activity of Resveratrol was significantly attenuated. Glucose-induced MMP9 expression was also inhibited by SIRT1 in response to Resveratrol. These data consistently suggest that SIRT1 directly inhibits the transcriptional activity of AP-1 by targeting c-JUN.« less

  4. Cortical Activity during Manual Response Inhibition Guided by Color and Orientation Cues

    PubMed Central

    Cai, Weidong; Leung, Hoi-Chung

    2009-01-01

    It has been suggested that the right inferior frontal gyrus (IFG) plays a critical role in manual response inhibition, although neuroimaging studies of healthy adults have also reported widespread activations in other cortical regions during a variety of response inhibition tasks. We conducted a functional magnetic resonance imaging (fMRI) experiment to examine whether the activation of the IFG is dependent on the type of visuo-motor associations during response inhibition by varying the feature of the stop signal (color vs. orientation) in the stop-signal task. Results from 12 subjects showed that the bilateral ventral posterior IFG, anterior insula, inferior frontal junction (IFJ), middle temporal gyrus (MTG) and fusiform gyrus (FG) are active during response inhibition cued by both color and orientation stop signals. While only the MTG showed differential activity to the two stop signals, both MTG and FG showed significantly stronger activity during successful than unsuccessful stopping of unwanted responses cued by orientation and color, respectively. Our findings suggest that the right ventral posterior IFG may play a more general role in response inhibition regardless of the feature of the visual signal, while successful inhibition may depend on efficient processing of the signal. PMID:19401178

  5. Luteolin, a flavonoid, inhibits AP-1 activation by basophils.

    PubMed

    Hirano, Toru; Higa, Shinji; Arimitsu, Junsuke; Naka, Tetsuji; Ogata, Atsushi; Shima, Yoshihito; Fujimoto, Minoru; Yamadori, Tomoki; Ohkawara, Tomoharu; Kuwabara, Yusuke; Kawai, Mari; Matsuda, Hisashi; Yoshikawa, Masayuki; Maezaki, Naoyoshi; Tanaka, Tetsuaki; Kawase, Ichiro; Tanaka, Toshio

    2006-02-03

    Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812 cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1.

  6. Luteolin, a flavonoid, inhibits AP-1 activation by basophils

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hirano, Toru; Higa, Shinji; Arimitsu, Junsuke

    Flavonoids including luteolin, apigenin, and fisetin are inhibitors of IL-4 synthesis and CD40 ligand expression by basophils. This study was done to search for compounds with greater inhibitory activity of IL-4 expression and to clarify the molecular mechanisms through which flavonoids inhibit their expression. Of the 37 flavonoids and related compounds examined, ayanin, luteolin, and apigenin were the strongest inhibitors of IL-4 production by purified basophils in response to anti-IgE antibody plus IL-3. Luteolin did not suppress Syk or Lyn phosphorylation in basophils, nor did suppress p54/46 SAPK/JNK, p38 MAPK, and p44/42 MAPK activation by a basophilic cell line, KU812more » cells, stimulated with A23187 and PMA. However, luteolin did inhibit phosphorylation of c-Jun and DNA binding activity of AP-1 in nuclear lysates from stimulated KU812 cells. These results provide a fundamental structure of flavonoids for IL-4 inhibition and demonstrate a novel action of flavonoids that suppresses the activation of AP-1.« less

  7. Inhibition of polyphenol oxidases activity by various dipeptides.

    PubMed

    Girelli, Anna M; Mattei, Enrico; Messina, Antonella; Tarola, Anna M

    2004-05-19

    In an effort to develop natural and nontoxic inhibitors on the activity of mushroom polyphenol oxidase (PPO) the effect of various glycyl-dipeptides (GlyAsp, GlyGly, GlyHis, GlyLeu, GlyLys, GlyPhe, GlyPro, GlyTyr) was investigated. The inhibition study with dihydroxyphenylalanine (DOPA) as substrate is based on separation of the enzymatic reaction components by reversed phase HPLC and the UV detection of the dopachrome formed. The results have evidenced that several of tested dipeptides inhibited PPO activity in the range of 20-40% while GlyPro and GlyLeu had no effect. The study has also permitted the characterization of the following kinetic pattern: a linear-mixed-type mechanism for GlyAsp, GlyGly, GlyLys, and GlyPhe and a hyperbolic-mixed-type for GlyTyr. It was not possible to identify the inhibition mechanism for GlyHis, although it affects PPO activity. In addition the effects of GlyAsp, GlyLys and GlyHis were evaluated for lessening the browning of fresh Golden Delicious apple and Irish White Skinned potato. The effectiveness of such inhibitors was determined by the difference between the colors observed in the dipeptide-treated sample and the controls using the color space CIE-Lab system. The % browning inhibition on potato (20-50%) was greater than of apple (20-30%) by the all tested dipeptides. Only GlyLys presented the significant value of 50%.

  8. Inhibition of cathelicidin activity by bacterial exopolysaccharides.

    PubMed

    Foschiatti, Michela; Cescutti, Paola; Tossi, Alessandro; Rizzo, Roberto

    2009-06-01

    The interaction of bacterial exopolysaccharides, produced by opportunistic lung pathogens, with antimicrobial peptides of the innate primate immune system was investigated. The exopolysaccharides were produced by Pseudomonas aeruginosa, Inquilinus limosus and clinical isolates of the Burkholderia cepacia complex, bacteria that are all involved in lung infections of cystic fibrosis patients. The effects of the biological activities of three orthologous cathelicidins from Homo sapiens sapiens, Pongo pygmaeus (orangutan) and Presbitys obscurus (dusky leaf monkey) were examined. Inhibition of the antimicrobial activity of peptides was assessed using minimum inhibitory concentration assays on a reference Escherichia coli strain in the presence and absence of exopolysaccharides, whereas complex formation between peptides and exopolysaccharides was investigated by means of circular dichroism, fluorescence spectroscopy and atomic force microscopy. Biological assays revealed that the higher the negative charge of exopolysaccharides the stronger was their inhibiting effect. Spectroscopic studies indicated the formation of molecular complexes of varying stability between peptides and exopolysaccharides, explaining the inhibition. Atomic force microscopy provided a direct visualization of the molecular complexes. A model is proposed where peptides with an alpha-helical conformation interact with exopolysaccharides through electrostatic and other non-covalent interactions.

  9. 18β-Glycyrrhetinic acid preferentially blocks late Na current generated by ΔKPQ Nav1.5 channels

    PubMed Central

    Du, Yi-mei; Xia, Cheng-kun; Zhao, Ning; Dong, Qian; Lei, Ming; Xia, Jia-hong

    2012-01-01

    Aim: To compare the effects of two stereoisomeric forms of glycyrrhetinic acid on different components of Na+ current, HERG and Kv1.5 channel currents. Methods: Wild-type (WT) and long QT syndrome type 3 (LQT-3) mutant ΔKPQ Nav1.5 channels, as well as HERG and Kv1.5 channels were expressed in Xenopus oocytes. In addition, isolated human atrial myocytes were used. Two-microelectrode voltage-clamp technique was used to record the voltage-activated currents. Results: Superfusion of 18β-glycyrrhetinic acid (18β-GA, 1–100 μmol/L) blocked both the peak current (INa,P) and late current (INa,L) generated by WT and ΔKPQ Nav1.5 channels in a concentration-dependent manner, while 18α-glycyrrhetinic acid (18α-GA) at the same concentrations had no effects. 18β-GA preferentially blocked INa,L (IC50=37.2±14.4 μmol/L) to INa,P (IC50=100.4±11.2 μmol/L) generated by ΔKPQ Nav1.5 channels. In human atrial myocytes, 18β-GA (30 μmol/L) inhibited 47% of INa,P and 87% of INa,L induced by Anemonia sulcata toxin (ATX-II, 30 nmol/L). Superfusion of 18β-GA (100 μmol/L) had no effects on HERG and Kv1.5 channel currents. Conclusion: 18β-GA preferentially blocked the late Na current without affecting HERG and Kv1.5 channels. PMID:22609834

  10. Internal Structure and Preferential Protein Binding of Colloidal Aggregates.

    PubMed

    Duan, Da; Torosyan, Hayarpi; Elnatan, Daniel; McLaughlin, Christopher K; Logie, Jennifer; Shoichet, Molly S; Agard, David A; Shoichet, Brian K

    2017-01-20

    Colloidal aggregates of small molecules are the most common artifact in early drug discovery, sequestering and inhibiting target proteins without specificity. Understanding their structure and mechanism has been crucial to developing tools to control for, and occasionally even exploit, these particles. Unfortunately, their polydispersity and transient stability have prevented exploration of certain elementary properties, such as how they pack. Dye-stabilized colloidal aggregates exhibit enhanced homogeneity and stability when compared to conventional colloidal aggregates, enabling investigation of some of these properties. By small-angle X-ray scattering and multiangle light scattering, pair distance distribution functions suggest that the dye-stabilized colloids are filled, not hollow, spheres. Stability of the coformulated colloids enabled investigation of their preference for binding DNA, peptides, or folded proteins, and their ability to purify one from the other. The coformulated colloids showed little ability to bind DNA. Correspondingly, the colloids preferentially sequestered protein from even a 1600-fold excess of peptides that are themselves the result of a digest of the same protein. This may reflect the avidity advantage that a protein has in a surface-to-surface interaction with the colloids. For the first time, colloids could be shown to have preferences of up to 90-fold for particular proteins over others. Loaded onto the colloids, bound enzyme could be spun down, resuspended, and released back into buffer, regaining most of its activity. Implications of these observations for colloid mechanisms and utility will be considered.

  11. Trastuzumab has preferential activity against breast cancers driven by HER2 homodimers

    PubMed Central

    Ghosh, Ritwik; Narasanna, Archana; Wang, Shizhen Emily; Liu, Shuying; Chakrabarty, Anindita; Balko, Justin M.; González-Angulo, Ana María; Mills, Gordon B.; Penuel, Elicia; Winslow, John; Sperinde, Jeff; Dua, Rajiv; Pidaparthi, Sailaja; Mukherjee, Ali; Leitzel, Kim; Kostler, Wolfgang J.; Lipton, Allan; Bates, Michael; Arteaga, Carlos L.

    2011-01-01

    In breast cancer cells with HER2 gene amplification, HER2 receptors exist on the cell surface as monomers, homodimers and heterodimers with EGFR/HER3. The therapeutic antibody trastuzumab, an approved therapy for HER2+ breast cancer, cannot block ligand-induced HER2 heterodimers, suggesting it cannot effectively inhibit HER2 signaling. Hence, HER2 oligomeric states may predict the odds of a clinical response to trastuzumab in HER2-driven tumors. To test this hypothesis, we generated non-transformed human MCF10A mammary epithelial cells stably expressing a chimeric HER2-FKBP molecule that could be conditionally induced to homodimerize by adding the FKBP ligand AP1510, or instead induced to heterodimerize with EGFR or HER3 by adding the heterodimer ligands EGF/TGFα or heregulin. AP1510, EGF, and heregulin each induced growth of MCF10A cells expressing HER2-FKBP. As expected, trastuzumab inhibited homodimer-mediated but not heterodimer-mediated cell growth. In contrast, the HER2 antibody pertuzumab, which blocks HER2 heterodimerization, inhibited growth induced by heregulin but not AP1510. Lastly, HER2/EGFR tyrosine kinase inhibitor lapatinib blocked both homodimer- and heterodimer-induced growth. AP1510 triggered phosphorylation of Erk1/2 but not AKT, whereas trastuzumab inhibited AP1510-induced Erk1/2 phosphorylation and Shc-HER2 homodimer binding, but not TGFα-induced AKT phosphorylation. Consistent with these observations, high levels of HER2 homodimers correlated with longer time to progression following trastuzumab therapy in a cohort of HER2-overexpressing patients. Together, our findings corroborate the hypothesis that HER2 oligomeric states regulate HER2 signaling, also arguing that trastuzumab sensitivity of homodimers reflects an inability to activate the PI3K/AKT pathway. One of the most important clinical implications of our results is that high levels of HER2 homodimers may predict a positive response to trastuzumab. PMID:21324925

  12. Auto-inhibition and phosphorylation-induced activation of PLC-γ isozymes

    PubMed Central

    Hajicek, Nicole; Charpentier, Thomas H.; Rush, Jeremy R.; Harden, T. Kendall; Sondek, John

    2013-01-01

    Multiple extracellular stimuli, such as growth factors and antigens, initiate signaling cascades through tyrosine phosphorylation and activation of phospholipase C (PLC)-γ isozymes. Like most other PLCs, PLC-γ1 is basally auto-inhibited by its X-Y linker, which separates the X-and Y-boxes of the catalytic core. The C-terminal SH2 (cSH2) domain within the X-Y linker is the critical determinant for auto-inhibition of phospholipase activity. Release of auto-inhibition requires an intramolecular interaction between the cSH2 domain and a phosphorylated tyrosine, Tyr783, also located within the X-Y linker. The molecular mechanisms that mediate auto-inhibition and phosphorylation-induced activation have not been defined. Here, we describe structures of the cSH2 domain both alone and bound to a PLC-γ1 peptide encompassing phosphorylated Tyr783. The cSH2 domain remains largely unaltered by peptide engagement. Point mutations in the cSH2 domain located at the interface with the peptide were sufficient to constitutively activate PLC-γ1 suggesting that peptide engagement directly interferes with the capacity of the cSH2 domain to block the lipase active site. This idea is supported by mutations in a complimentary surface of the catalytic core that also enhanced phospholipase activity. PMID:23777354

  13. Inhibition of ATPase activity in rat synaptic plasma membranes by simultaneous exposure to metals.

    PubMed

    Carfagna, M A; Ponsler, G D; Muhoberac, B B

    1996-03-08

    Inhibition of Na+/K+-ATPase and Mg2+-ATPase activities by in vitro exposure to Cd2+, Pb2+ and Mn2+ was investigated in rat brain synaptic plasma membranes (SPMs). Cd2+ and Pb2+ produced a larger maximal inhibition of Na+/K+-ATPase than of Mg2+-ATPase activity. Metal concentrations causing 50% inhibition of Na+/K+-ATPase activity (IC50 values) were Cd2+ (0.6 microM) < Pb2+ (2.1 microM) < Mn2+ (approximately 3 mM), and the former two metals were substantially more potent in inhibiting SPM versus synaptosomal Na+/K+-ATPase. Dixon plots of SPM data indicated that equilibrium binding of metals occurs at sites causing enzyme inhibition. In addition, IC50 values for SPM K+-dependent p-nitrophenylphosphatase inhibition followed the same order and were Cd2+ (0.4 microM) < Pb2+ (1.2 microM) < Mn2+ (300 microM). Simultaneous exposure to the combinations Cd2+/Mn2+ or Pb2+/Mn2+ inhibited SPM Na+/K+-ATPase activity synergistically (i.e., greater than the sum of the metal-induced inhibitions assayed separately), while Cd2+/Pb2+ caused additive inhibition. Simultaneous exposure to Cd2+/Pb2+ antagonistically inhibited Mg2+-ATPase activity while Cd2+/Mn2+ or Pb2+/Mn2+ additively inhibited Mg2+-ATPase activity at low Mn2+ concentrations, but inhibited antagonistically at higher concentrations. The similar IC50 values for Cd2+ and Pb2+ versus Mn2+ inhibition of Na+/K+-ATPase and the pattern of inhibition/activation upon exposure to two metals simultaneously support similar modes of interaction of Cd2+ and Pb2+ with this enzyme, in agreement with their chemical reactivities.

  14. Inhibition of ammonia poisoning by addition of platinum to Ru/α-Al2 O3 for preferential CO oxidation in fuel cells.

    PubMed

    Sato, Katsutoshi; Yagi, Sho; Zaitsu, Shuhei; Kitayama, Godai; Kayada, Yuto; Teramura, Kentaro; Takita, Yusaku; Nagaoka, Katsutoshi

    2014-12-01

    In polymer electrolyte fuel cell (PEFC) systems, small amounts of ammonia (NH3 ) present in the reformate gas deactivate the supported ruthenium catalysts used for preferential oxidation (PROX) of carbon monoxide (CO). In this study, we investigated how the addition of a small amount of platinum to a Ru/α-Al2 O3 catalyst (Pt/Ru=1:9 w/w) affected the catalyst's PROX activity in both the absence and the presence of NH3 (130 ppm) under conditions mimicking the reformate conditions during steam reforming of natural gas. The activity of undoped Ru/α-Al2 O3 decreased sharply upon addition of NH3 , whereas Pt/Ru/α-Al2 O3 exhibited excellent PROX activity even in the presence of NH3 . Ruthenium K-edge X-ray absorption near-edge structure (XANES) spectra indicated that in the presence of NH3 , some of the ruthenium in the undoped catalyst was oxidized in the presence of NH3 , whereas ruthenium oxidation was not observed with Pt/Ru/α-Al2 O3 . These results suggest that ruthenium oxidation is retarded by the platinum, so that the catalyst shows high activity even in the presence of NH3 . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. H-Ferritin Is Preferentially Incorporated by Human Erythroid Cells through Transferrin Receptor 1 in a Threshold-Dependent Manner

    PubMed Central

    Sakamoto, Soichiro; Kawabata, Hiroshi; Masuda, Taro; Uchiyama, Tatsuki; Mizumoto, Chisaki; Ohmori, Katsuyuki; Koeffler, H. Phillip; Kadowaki, Norimitsu; Takaori-Kondo, Akifumi

    2015-01-01

    Ferritin is an iron-storage protein composed of different ratios of 24 light (L) and heavy (H) subunits. The serum level of ferritin is a clinical marker of the body’s iron level. Transferrin receptor (TFR)1 is the receptor not only for transferrin but also for H-ferritin, but how it binds two different ligands and the blood cell types that preferentially incorporate H-ferritin remain unknown. To address these questions, we investigated hematopoietic cell-specific ferritin uptake by flow cytometry. Alexa Fluor 488-labeled H-ferritin was preferentially incorporated by erythroid cells among various hematopoietic cell lines examined, and was almost exclusively incorporated by bone marrow erythroblasts among human primary hematopoietic cells of various lineages. H-ferritin uptake by erythroid cells was strongly inhibited by unlabeled H-ferritin but was only partially inhibited by a large excess of holo-transferrin. On the other hand, internalization of labeled holo-transferrin by these cells was not inhibited by H-ferritin. Chinese hamster ovary cells lacking functional endogenous TFR1 but expressing human TFR1 with a mutated RGD sequence, which is required for transferrin binding, efficiently incorporated H-ferritin, indicating that TFR1 has distinct binding sites for H-ferritin and holo-transferrin. H-ferritin uptake by these cells required a threshold level of cell surface TFR1 expression, whereas there was no threshold for holo-transferrin uptake. The requirement for a threshold level of TFR1 expression can explain why among primary human hematopoietic cells, only erythroblasts efficiently take up H-ferritin. PMID:26441243

  16. Brain cholinesterase activities of passerine birds in forests sprayed with cholinesterase inhibiting insecticides

    USGS Publications Warehouse

    Zinkl, J.G.; Henny, C.J.; Shea, P.J.

    1979-01-01

    Brain cholinesterase activities were determined in passerines collected from northwestern forests that had been sprayed with trichlorfon, acephate, and carbaryl at 0.56, 1.13 and 2.26 kg/ha. Trichlorfon and carbaryl inhibited cholinesterase activity slightly in only a few birds, primarily canopy dwellers. In contrast, acephate caused marked inhibition of cholinesterase activity in nearly all birds collected. The inhibition was present even 33 days after spraying. Some birds from the acephate-sprayed forests exhibited clinical signs compatible with acute acetylcholinesterase inhibition.

  17. Student Incentives and Preferential Treatment in College Admissions

    ERIC Educational Resources Information Center

    Pastine, Ivan; Pastine, Tuvana

    2012-01-01

    We consider a framework in which the optimal admissions policy of a purely academic-quality oriented college implements preferential treatment in favor of the student from the deprived socioeconomic background which maximizes the competition between candidates. We find that the exact form of the preferential treatment admissions policy matters for…

  18. Preferential inhibition of xanthine oxidase by 2-amino-6-hydroxy-8-mercaptopurine and 2-amino-6-purine thiol

    PubMed Central

    Kalra, Sukirti; Jena, Gopabandhu; Tikoo, Kulbhushan; Mukhopadhyay, Anup Kumar

    2007-01-01

    Background The anticancer drug, 6-mercaptopurine (6MP) is subjected to metabolic clearance through xanthine oxidase (XOD) mediated hydroxylation, producing 6-thiouric acid (6TUA), which is excreted in urine. This reduces the effective amount of drug available for therapeutic efficacy. Co-administration of allopurinol, a suicide inhibitor of XOD, which blocks the hydroxylation of 6MP inadvertently enhances the 6MP blood level, counters this reduction. However, allopurinol also blocks the hydroxylation of hypoxanthine, xanthine (released from dead cancer cells) leading to their accumulation in the body causing biochemical complications such as xanthine nephropathy. This necessitates the use of a preferential XOD inhibitor that selectively inhibits 6MP transformation, but leaves xanthine metabolism unaffected. Results Here, we have characterized two such unique inhibitors namely, 2-amino-6-hydroxy-8-mercaptopurine (AHMP) and 2-amino-6-purinethiol (APT) on the basis of IC50 values, residual activity in bi-substrate simulative reaction and the kinetic parameters like Km, Ki, kcat. The IC50 values of AHMP for xanthine and 6MP as substrate are 17.71 ± 0.29 μM and 0.54 ± 0.01 μM, respectively and the IC50 values of APT for xanthine and 6MP as substrates are 16.38 ± 0.21 μM and 2.57 ± 0.08 μM, respectively. The Ki values of XOD using AHMP as inhibitor with xanthine and 6MP as substrate are 5.78 ± 0.48 μM and 0.96 ± 0.01 μM, respectively. The Ki values of XOD using APT as inhibitor with xanthine and 6MP as substrate are 6.61 ± 0.28 μM and 1.30 ± 0.09 μM. The corresponding Km values of XOD using xanthine and 6MP as substrate are 2.65 ± 0.02 μM and 6.01 ± 0.03 μM, respectively. The results suggest that the efficiency of substrate binding to XOD and its subsequent catalytic hydroxylation is much superior for xanthine in comparison to 6MP. In addition, the efficiency of the inhibitor binding to XOD is much more superior when 6MP is the substrate instead of

  19. Preferential inhibition of xanthine oxidase by 2-amino-6-hydroxy-8-mercaptopurine and 2-amino-6-purine thiol.

    PubMed

    Kalra, Sukirti; Jena, Gopabandhu; Tikoo, Kulbhushan; Mukhopadhyay, Anup Kumar

    2007-05-18

    The anticancer drug, 6-mercaptopurine (6MP) is subjected to metabolic clearance through xanthine oxidase (XOD) mediated hydroxylation, producing 6-thiouric acid (6TUA), which is excreted in urine. This reduces the effective amount of drug available for therapeutic efficacy. Co-administration of allopurinol, a suicide inhibitor of XOD, which blocks the hydroxylation of 6MP inadvertently enhances the 6MP blood level, counters this reduction. However, allopurinol also blocks the hydroxylation of hypoxanthine, xanthine (released from dead cancer cells) leading to their accumulation in the body causing biochemical complications such as xanthine nephropathy. This necessitates the use of a preferential XOD inhibitor that selectively inhibits 6MP transformation, but leaves xanthine metabolism unaffected. Here, we have characterized two such unique inhibitors namely, 2-amino-6-hydroxy-8-mercaptopurine (AHMP) and 2-amino-6-purinethiol (APT) on the basis of IC50 values, residual activity in bi-substrate simulative reaction and the kinetic parameters like Km, Ki, kcat. The IC50 values of AHMP for xanthine and 6MP as substrate are 17.71 +/- 0.29 microM and 0.54 +/- 0.01 microM, respectively and the IC50 values of APT for xanthine and 6MP as substrates are 16.38 +/- 0.21 microM and 2.57 +/- 0.08 microM, respectively. The Ki values of XOD using AHMP as inhibitor with xanthine and 6MP as substrate are 5.78 +/- 0.48 microM and 0.96 +/- 0.01 microM, respectively. The Ki values of XOD using APT as inhibitor with xanthine and 6MP as substrate are 6.61 +/- 0.28 microM and 1.30 +/- 0.09 microM. The corresponding Km values of XOD using xanthine and 6MP as substrate are 2.65 +/- 0.02 microM and 6.01 +/- 0.03 microM, respectively. The results suggest that the efficiency of substrate binding to XOD and its subsequent catalytic hydroxylation is much superior for xanthine in comparison to 6MP. In addition, the efficiency of the inhibitor binding to XOD is much more superior when 6MP is the

  20. Reverse preferential spread in complex networks

    NASA Astrophysics Data System (ADS)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  1. Non-competitive inhibition by active site binders.

    PubMed

    Blat, Yuval

    2010-06-01

    Classical enzymology has been used for generations to understand the interactions of inhibitors with their enzyme targets. Enzymology tools enabled prediction of the biological impact of inhibitors as well as the development of novel, more potent, ones. Experiments designed to examine the competition between the tested inhibitor and the enzyme substrate(s) are the tool of choice to identify inhibitors that bind in the active site. Competition between an inhibitor and a substrate is considered a strong evidence for binding of the inhibitor in the active site, while the lack of competition suggests binding to an alternative site. Nevertheless, exceptions to this notion do exist. Active site-binding inhibitors can display non-competitive inhibition patterns. This unusual behavior has been observed with enzymes utilizing an exosite for substrate binding, isomechanism enzymes, enzymes with multiple substrates and/or products and two-step binding inhibitors. In many of these cases, the mechanisms underlying the lack of competition between the substrate and the inhibitor are well understood. Tools like alternative substrates, testing the enzyme reaction in the reverse direction and monitoring inhibition time dependence can be applied to enable distinction between 'badly behaving' active site binders and true exosite inhibitors.

  2. Mesencephalic stimulation elicits inhibition of phrenic nerve activity in cat.

    PubMed Central

    Gallman, E A; Lawing, W L; Millhorn, D E

    1991-01-01

    1. Previous work from this laboratory has indicated that the mesencephalon is the anatomical substrate for a mechanism capable of inhibiting central respiratory drive in glomectomized cats for periods of up to 1 h or more following brief exposure to systemic hypoxia; phrenic nerve activity was used as an index of central respiratory drive. 2. The present study was undertaken to further localize the region responsible for the observed post-hypoxic inhibition of respiratory drive. We studied the phrenic nerve response to stimulations of the mesencephalon in anaesthetized, paralysed peripherally chemo-denervated cats with end-expired PCO2 and body temperature servo-controlled. 3. Stimulations of two types were employed. Electrical stimulation allowed rapid determination of sites from which phrenic inhibition could be elicited. Microinjections of excitatory amino acids were used subsequently in order to confine excitation to neuronal cell bodies and not axons of passage. 4. Stimulation of discrete regions of the ventromedial aspect of the mesencephalon in the vicinity of the red nucleus produced substantial inhibition of phrenic activity which lasted up to 45 min. Stimulation of other areas of the mesencephalon either produced no phrenic inhibition or resulted in a slight stimulation of phrenic activity. 5. The results are discussed in the context of the central respiratory response to hypoxia. PMID:1676420

  3. Antiausterity activity of arctigenin enantiomers: importance of (2R,3R)-absolute configuration.

    PubMed

    Awale, Suresh; Kato, Mamoru; Dibwe, Dya Fita; Li, Feng; Miyoshi, Chika; Esumi, Hiroyasu; Kadota, Shigetoshi; Tezuka, Yasuhiro

    2014-01-01

    From a MeOH extract of powdered roots of Wikstroemia indica, six dibenzyl-gamma-butyrolactone-type lignans with (2S,3S)-absolute configuration [(+)-arctigenin (1), (+)-matairesinol (2), (+)-trachelogenin (3), (+)-nortrachelogenin (4), (+)-hinokinin (5), and (+)-kusunokinin (6)] were isolated, whereas three dibenzyl-gamma-butyrolactone-type lignans with (2R,3R)-absolute configuration [(-)-arctigenin (1*), (-)-matairesinol (2*), (-)-trachelogenin (3*)] were isolated from Trachelospermum asiaticum. The in vitro preferential cytotoxic activity of the nine compounds was evaluated against human pancreatic PANC-1 cancer cells in nutrient-deprived medium (NDM), but none of the six lignans (1-6) with (2S,3S)-absolute configuration showed preferential cytotoxicity. On the other hand, three lignans (1*-3*) with (2R,3R)-absolute configuration exhibited preferential cytotoxicity in a concentration-dependent manner with PC50 values of 0.54, 6.82, and 5.85 microM, respectively. Furthermore, the effect of (-)- and (+)-arctigenin was evaluated against the activation of Akt, which is a key process in the tolerance to nutrition starvation. Interestingly, only (-)-arctigenin (1*) strongly suppressed the activation of Akt. These results indicate that the (2R,3R)-absolute configuration of (-)-enantiomers should be required for the preferential cytotoxicity through the inhibition of Akt activation.

  4. PDGF-A suppresses contact inhibition during directional collective cell migration.

    PubMed

    Nagel, Martina; Winklbauer, Rudolf

    2018-06-08

    The leading edge mesendoderm (LEM) of the Xenopus gastrula moves as an aggregate by collective migration. However, LEM cells on fibronectin in vitro show contact inhibition of locomotion by quickly retracting lamellipodia upon mutual contact. We found that a fibronectin-integrin-syndecan module acts between p21-activated kinase-1 upstream and ephrinB1 downstream to promote the contact-induced collapse of lamellipodia. To function in this module, fibronectin has to be present as puncta on the surface of LEM cells. To overcome contact inhibition in LEM cell aggregates, PDGF-A deposited in the endogenous substratum of LEM migration blocks the fibronectin-integrin-syndecan module at the integrin level. This stabilizes lamellipodia preferentially in the direction of normal LEM movement and supports cell orientation and the directional migration of the coherent LEM cell mass. © 2018. Published by The Company of Biologists Ltd.

  5. Preferential cytotoxicity of bortezomib toward highly malignant human liposarcoma cells via suppression of MDR1 expression and function

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hu, Yamei; Wang, Lingxian; Wang, Lu

    2015-02-15

    Liposarcoma is the most common soft tissue sarcoma with a high risk of relapse. Few therapeutic options are available for the aggressive local or metastatic disease. Here, we report that the clinically used proteasome inhibitor bortezomib exhibits significantly stronger cytotoxicity toward highly malignant human liposarcoma SW872-S cells compared with its parental SW872 cells, which is accompanied by enhanced activation of apoptotic signaling both in vitro and in vivo. Treatment of cells with Jun-N-terminal kinase (JNK) inhibitor SP60015 or the translation inhibitor cycloheximide ameliorated this enhanced apoptosis. Bortezomib inhibited MDR1 expression and function more effectively in SW872-S cells than in SW872more » cells, indicating that the increased cytotoxicity relies on the degree of proteasome inhibition. Furthermore, the pharmacological or genetic inhibition of sarco/endoplasmic reticulum calcium-ATPase (SERCA) 2, which is highly expressed in SW872-S cells, resulted in partial reversal of cell growth inhibition and increase of MDR1 expression in bortezomib-treated SW872-S cells. These results show that bortezomib exhibits preferential cytotoxicity toward SW872-S cells possibly via highly expressed SERCA2-associated MDR1 suppression and suggest that bortezomib may serve as a potent agent for treating advanced liposarcoma. - Highlights: • We compare the cytotoxicity of different drugs between SW872-S and SW872 cells. • Highly malignant liposarcoma cells SW872-S show hypersensitivity to bortezomib. • Apoptotic signaling is robustly enhanced in bortezomib-treated SW872-S cells. • Bortezomib has strong suppression on MDR1 expression and function in SW872-S cells. • Inhibition of SERCA2 protects SW872-S cells from bortezomib.« less

  6. D-tyrosine negatively regulates melanin synthesis by competitively inhibiting tyrosinase activity.

    PubMed

    Park, Jisu; Jung, Hyejung; Kim, Kyuri; Lim, Kyung-Min; Kim, Ji-Young; Jho, Eek-Hoon; Oh, Eok-Soo

    2018-05-01

    Although L-tyrosine is well known for its melanogenic effect, the contribution of D-tyrosine to melanin synthesis was previously unexplored. Here, we reveal that, unlike L-tyrosine, D-tyrosine dose-dependently reduced the melanin contents of human MNT-1 melanoma cells and primary human melanocytes. In addition, 500 μM of D-tyrosine completely inhibited 10 μM L-tyrosine-induced melanogenesis, and both in vitro assays and L-DOPA staining MNT-1 cells showed that tyrosinase activity is reduced by D-tyrosine treatment. Thus, D-tyrosine appears to inhibit L-tyrosine-mediated melanogenesis by competitively inhibiting tyrosinase activity. Furthermore, we found that D-tyrosine inhibited melanogenesis induced by α-MSH treatment or UV irradiation, which are the most common environmental factors responsible for melanin synthesis. Finally, we confirmed that D-tyrosine reduced melanin synthesis in the epidermal basal layer of a 3D human skin model. Taken together, these data suggest that D-tyrosine negatively regulates melanin synthesis by inhibiting tyrosinase activity in melanocyte-derived cells. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Reversal of androgen inhibition of estrogen-activated sexual behavior by cholinergic agents.

    PubMed

    Dohanich, G P; Cada, D A

    1989-12-01

    Androgens have been found to inhibit lordosis activated by estrogen treatment of ovariectomized female rats. In the present experiments, dihydrotestosterone propionate (200 micrograms for 3 days) inhibited the incidence of lordosis in ovariectomized females treated with estradiol benzoate (1 microgram for 3 days). This inhibition of lordosis was reversed 15 min after bilateral intraventricular infusion of physostigmine (10 micrograms/cannula), an acetylcholinesterase inhibitor, or carbachol (0.5 microgram/cannula), a cholinergic receptor agonist. This reversal of inhibition appears to be mediated by cholinergic muscarinic receptors since pretreatment with scopolamine (4 mg/kg, ip), a muscarinic receptor blocker, prevented the reversal of androgen inhibition by physostigmine. These results indicate that androgens may inhibit estrogen-activated lordosis through interference with central cholinergic muscarinic mechanisms.

  8. T-kininogen inhibits kinin-mediated activation of ERK in endothelial cells.

    PubMed

    Leiva-Salcedo, Elias; Perez, Viviana; Acuña-Castillo, Claudio; Walter, Robin; Sierra, Felipe

    2002-01-01

    Serum levels of T-kininogen increase dramatically as rats approach the end of their lifespan. Stable expression of the protein in Balb/c 3T3 fibroblasts leads to a dramatic inhibition of cell proliferation, as well as inhibition of the ERK signaling pathway. T-kininogen is a potent inhibitor of cysteine proteinases, and we have described that the inhibition of ERK activity occurs, at least in part, via stabilization of the MAP kinase phosphatase, MKP-1. Since fibroblasts are not a physiological target of T-kininogen, we have now purified the protein from rat serum, and used it to assess the effect of T-kininogen on endothelial cells. Adding purified T-kininogen to EAhy 926 hybridoma cells resulted in inhibition of basal ERK activity levels, as estimated using appropriate anti-phospho ERK antibodies. Furthermore, exogenously added T-kininogen inhibited the activation of the ERK pathway induced by either bradykinin or T-kinin. We conclude that the age-related increase in hepatic T-kininogen gene expression and serum levels of the protein could have dramatic consequences on endothelial cell physiology, both under steady state conditions, and after activation by cell-specific stimuli. Our results are consistent with T-kininogen being an important modulator of the senescent phenotype in vivo.

  9. Houttuynia cordata blocks HSV infection through inhibition of NF-κB activation.

    PubMed

    Chen, Xiaoqing; Wang, Zhongxia; Yang, Ziying; Wang, Jingjing; Xu, Yunxia; Tan, Ren-Xiang; Li, Erguang

    2011-11-01

    Houttuynia cordata Thunb. is a medicinal plant widely used in folk medicine in several Asian countries. It has been reported that a water extract of H. cordata exhibits activity against herpes simplex virus (HSV) and the virus of severe acute respiratory syndrome (SARS), although the mechanisms are not fully understood yet. Previous studies have demonstrated absolute requirement of NF-κB activation for efficient replication of HSV-1 and HSV-2 and inhibition of NF-κB activation has been shown to suppress HSV infection. Here we show that a hot water extract of H. cordata (HCWE) inhibits HSV-2 infection through inhibition of NF-κB activation. The IC(50) was estimated at 50 μg/ml of lyophilized HCWE powder. At 150 and 450 μg/ml, HCWE blocked infectious HSV-2 production by more than 3 and 4 logs, respectively. The inhibitory activity was concomitant with an inhibition of NF-κB activation by HSV-2 infection. Although activation of NF-κB and Erk MAPK has been implicated for HSV replication and growth, HCWE showed no effect on HSV-2-induced Erk activation. Furthermore, we show that treatment with quercetin, quercitrin or isoquercitrin, major water extractable flavonoids from H. cordata, significantly blocked HSV-2 infection. These results together demonstrated that H. cordata blocks HSV-2 infection through inhibition of NF-κB activation. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Phenobarbital indirectly activates the constitutive active androstane receptor (CAR) by inhibition of epidermal growth factor receptor signaling

    PubMed Central

    Mutoh, Shingo; Sobhany, Mack; Moore, Rick; Perera, Lalith; Pedersen, Lee; Sueyoshi, Tatsuya; Negishi, Masahiko

    2017-01-01

    Phenobarbital is a central nervous system depressant that also indirectly activates nuclear receptor constitutive active androstane receptor (CAR), which promotes drug and energy metabolism, as well as cell growth (and death), in the liver. We found that phenobarbital activated CAR by inhibiting epidermal growth factor receptor (EGFR) signaling. Phenobarbital bound to EGFR and potently inhibited the binding of EGF, which prevented the activation of EGFR. This abrogation of EGFR signaling induced the dephosphorylation of receptor for activated C kinase 1 (RACK1) at Tyr52, which then promoted the dephosphorylation of CAR at Thr38 by the catalytic core subunit of protein phosphatase 2A. The findings demonstrated that the phenobarbital-induced mechanism of CAR dephosphorylation and activation is mediated through its direct interaction with and inhibition of EGFR. PMID:23652203

  11. Phenobarbital indirectly activates the constitutive active androstane receptor (CAR) by inhibition of epidermal growth factor receptor signaling.

    PubMed

    Mutoh, Shingo; Sobhany, Mack; Moore, Rick; Perera, Lalith; Pedersen, Lee; Sueyoshi, Tatsuya; Negishi, Masahiko

    2013-05-07

    Phenobarbital is a central nervous system depressant that also indirectly activates nuclear receptor constitutive active androstane receptor (CAR), which promotes drug and energy metabolism, as well as cell growth (and death), in the liver. We found that phenobarbital activated CAR by inhibiting epidermal growth factor receptor (EGFR) signaling. Phenobarbital bound to EGFR and potently inhibited the binding of EGF, which prevented the activation of EGFR. This abrogation of EGFR signaling induced the dephosphorylation of receptor for activated C kinase 1 (RACK1) at Tyr(52), which then promoted the dephosphorylation of CAR at Thr(38) by the catalytic core subunit of protein phosphatase 2A. The findings demonstrated that the phenobarbital-induced mechanism of CAR dephosphorylation and activation is mediated through its direct interaction with and inhibition of EGFR.

  12. S-Enantiomer of 19-Hydroxyeicosatetraenoic Acid Preferentially Protects Against Angiotensin II-Induced Cardiac Hypertrophy.

    PubMed

    Shoieb, Sherif M; El-Kadi, Ayman O S

    2018-06-07

    We have recently demonstrated that the racemic mixture of 19-hydroxyeicosatetraenoic acid (19-HETE) protects against angiotensin II (Ang II) induced cardiac hypertrophy. Therefore, the purpose of this study was to investigate whether R- or S-enantiomer of 19-HETE confers cardioprotection against Ang II-induced cellular hypertrophy in RL-14 and H9c2 cells. Both cell lines were treated with vehicle or 10 μM Ang II in the absence and presence of 20 &#[mu]M 19(R)-HETE or 19(S)-HETE for 24 h. Thereafter, the level of mid-chain HETEs was determined using liquid chromatography - mass spectrometry (LC/MS). Gene and protein expression levels were measured using real-time PCR and Western blot analysis, respectively. The results showed that both 19(R)-HETE and 19(S)-HETE significantly decreased the metabolite formation rate of midchain HETEs namely 8-, 9-, 12- and 15-HETE compared to control group while the level of 5-HETE was selectively decreased by S-enantiomer. Moreover, both 19(R)-HETE and 19(S)-HETE significantly inhibited the catalytic activity of CYP1B1 and decreased the protein expression of 5- and 12-lipoxxygenase (LOX) as well as cyclooxygenase-2 (COX-2). Notably, the decrease in 15-LOX protein expression was only mediated by 19(S)-HETE. Moreover, both enantiomers protected against Ang II-induced cellular hypertrophy as evidenced by a significant decrease in mRNA expression of β/α-myosin heavy chain ratio, ANP, IL-6 and IL-8. Our data demonstrated that S-enantiomer of 19-HETE preferentially protected against Ang II-induced cellular hypertrophy via decreasing the level of mid-chain HETEs, inhibiting catalytic activity of CYP1B1, decreasing protein expression of LOX and COX-2 enzymes and decreasing mRNA expression of IL-6 and IL-8. The American Society for Pharmacology and Experimental Therapeutics.

  13. Thymol inhibits Staphylococcus aureus internalization into bovine mammary epithelial cells by inhibiting NF-κB activation.

    PubMed

    Wei, Zhengkai; Zhou, Ershun; Guo, Changming; Fu, Yunhe; Yu, Yuqiang; Li, Yimeng; Yao, Minjun; Zhang, Naisheng; Yang, Zhengtao

    2014-01-01

    Bovine mastitis is one of the most costly and prevalent diseases in the dairy industry and is characterised by inflammatory and infectious processes. Staphylococcus aureus (S. aureus), a Gram-positive organism, is a frequent cause of subclinical, chronic mastitis. Thymol, a monocyclic monoterpene compound isolated from Thymus vulgaris, has been reported to have antibacterial properties. However, the effect of thymol on S. aureus internalization into bovine mammary epithelial cells (bMEC) has not been investigated. In this study, we evaluated the effect of thymol on S. aureus internalization into bMEC, the expression of tracheal antimicrobial peptide (TAP) and β-defensin (BNBD5), and the inhibition of NF-κB activation in bMEC infected with S. aureus. Our results showed that thymol (16-64 μg/ml) could reduce the internalization of S. aureus into bMEC and down-regulate the mRNA expression of TAP and BNBD5 in bMEC infected with S. aureus. In addition, thymol was found to inhibit S. aureus-induced nitric oxide (NO) production in bMEC and suppress S. aureus-induced NF-κB activation in a dose-dependent manner. In conclusion, these results indicated that thymol inhibits S. aureus internalization into bMEC by inhibiting NF-κB activation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Simultaneous activation of p53 and inhibition of XIAP enhance the activation of apoptosis signaling pathways in AML

    PubMed Central

    Carter, Bing Z.; Mak, Duncan H.; Schober, Wendy D.; Koller, Erich; Pinilla, Clemencia; Vassilev, Lyubomir T.; Reed, John C.

    2010-01-01

    Activation of p53 by murine double minute (MDM2) antagonist nutlin-3a or inhibition of X-linked inhibitor of apoptosis (XIAP) induces apoptosis in acute myeloid leukemia (AML) cells. We demonstrate that concomitant inhibition of MDM2 by nutlin-3a and of XIAP by small molecule antagonists synergistically induced apoptosis in p53 wild-type OCI-AML3 and Molm13 cells. Knockdown of p53 by shRNA blunted the synergy, and down-regulation of XIAP by antisense oligonucleotide (ASO) enhanced nutlin-3a–induced apoptosis, suggesting that the synergy was mediated by p53 activation and XIAP inhibition. This is supported by data showing that inhibition of both MDM2 and XIAP by their respective ASOs induced significantly more cell death than either ASO alone. Importantly, p53 activation and XIAP inhibition enhanced apoptosis in blasts from patients with primary AML, even when the cells were protected by stromal cells. Mechanistic studies demonstrated that XIAP inhibition potentiates p53-induced apoptosis by decreasing p53-induced p21 and that p53 activation enhances XIAP inhibition-induced cell death by promoting mitochondrial release of second mitochondria-derived activator of caspases (SMAC) and by inducing the expression of caspase-6. Because both XIAP and p53 are presently being targeted in ongoing clinical trials in leukemia, the combination strategy holds promise for expedited translation into the clinic. PMID:19897582

  15. Effect of mitochondrial complex I inhibition on Fe-S cluster protein activity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mena, Natalia P.; Millennium Institute of Cell Dynamics and Biotechnology, Santiago; Bulteau, Anne Laure

    2011-06-03

    Highlights: {yields} Mitochondrial complex I inhibition resulted in decreased activity of Fe-S containing enzymes mitochondrial aconitase and cytoplasmic aconitase and xanthine oxidase. {yields} Complex I inhibition resulted in the loss of Fe-S clusters in cytoplasmic aconitase and of glutamine phosphoribosyl pyrophosphate amidotransferase. {yields} Consistent with loss of cytoplasmic aconitase activity, an increase in iron regulatory protein 1 activity was found. {yields} Complex I inhibition resulted in an increase in the labile cytoplasmic iron pool. -- Abstract: Iron-sulfur (Fe-S) clusters are small inorganic cofactors formed by tetrahedral coordination of iron atoms with sulfur groups. Present in numerous proteins, these clusters aremore » involved in key biological processes such as electron transfer, metabolic and regulatory processes, DNA synthesis and repair and protein structure stabilization. Fe-S clusters are synthesized mainly in the mitochondrion, where they are directly incorporated into mitochondrial Fe-S cluster-containing proteins or exported for cytoplasmic and nuclear cluster-protein assembly. In this study, we tested the hypothesis that inhibition of mitochondrial complex I by rotenone decreases Fe-S cluster synthesis and cluster content and activity of Fe-S cluster-containing enzymes. Inhibition of complex I resulted in decreased activity of three Fe-S cluster-containing enzymes: mitochondrial and cytosolic aconitases and xanthine oxidase. In addition, the Fe-S cluster content of glutamine phosphoribosyl pyrophosphate amidotransferase and mitochondrial aconitase was dramatically decreased. The reduction in cytosolic aconitase activity was associated with an increase in iron regulatory protein (IRP) mRNA binding activity and with an increase in the cytoplasmic labile iron pool. Since IRP activity post-transcriptionally regulates the expression of iron import proteins, Fe-S cluster inhibition may result in a false iron deficiency signal. Given

  16. Stat3 inhibition activates tumor macrophages and abrogates glioma growth in mice.

    PubMed

    Zhang, Leying; Alizadeh, Darya; Van Handel, Michelle; Kortylewski, Marcin; Yu, Hua; Badie, Behnam

    2009-10-01

    As the main effector-cell population of the central nervous system, microglia (MG) are considered to play an important immunoregulatory function in a number of pathological conditions such as inflammation, trauma, degenerative disease, and brain tumors. Recent studies, however, have suggested that the anti-neoplastic function of MG may be suppressed in malignant brain tumors. Considering the proposed suppressive role of signal transducers and activators of transcription 3 (Stat3) in antitumor immunity, we evaluated the role of Stat3 inhibition on MG and macrophage (MP) activation and tumor growth in a murine glioma model. N9 MG cells were exposed to GL261 glioma conditioned medium (GL261-CM) and evaluated for Stat3 activity and cytokine expression. Furthermore, the role of Stat3 inhibition on MG and MP activation was studied both in vitro and in vivo. Finally, the effect of Stat3 inhibition on tumor growth was assessed in intracranial GL261 gliomas. GL261-CM increased Stat3 activity in N9 cells in vitro and resulted in overexpression of IL-10 and IL-6, and downregulation of IL1-beta, a pro-inflammatory cytokine. Inhibition of Stat3 by CPA-7 or siRNA reversed glioma-induced cytokine expression profile in N9 cells. Furthermore, inactivation of Stat3 in intracranial GL261 tumors by siRNA resulted in MG/MP activation and tumor growth inhibition. Glioma-induced MG and MP suppression may be mediated thorough Stat3. Inhibition of Stat3 function in tumor MG/MP may result in their activation and can potentially be used as an adjunct immunotherapy approach for gliomas.

  17. Preferentially Oriented Ag Nanocrystals with Extremely High Activity and Faradaic Efficiency for CO2 Electrochemical Reduction to CO.

    PubMed

    Peng, Xiong; Karakalos, Stavros G; Mustain, William E

    2018-01-17

    Selective electrochemical reduction of CO 2 is one of the most important processes to study because of its promise to convert this greenhouse gas to value-added chemicals at low cost. In this work, a simple anodization treatment was devised that first oxidizes Ag to Ag 2 CO 3 , then uses rapid electrochemical reduction to create preferentially oriented nanoparticles (PONs) of metallic Ag (PON-Ag) with high surface area as well as high activity and very high selectivity for the reduction of CO 2 to CO. The PON-Ag catalyst was dominated by (110) and (100) orientation, which allowed PON-Ag to achieve a CO Faradaic efficiency of 96.7% at an operating potential of -0.69 V vs RHE. This performance is not only significantly higher than that of polycrystalline Ag (60% at -0.87 V vs RHE) but also represents one of the best combinations of activity and selectivity achieved to date - all with a very simple, scalable approach to electrode fabrication.

  18. Inhibition of Interferon Regulatory Factor 3 Activation by Paramyxovirus V Protein

    PubMed Central

    Irie, Takashi; Kiyotani, Katsuhiro; Igarashi, Tomoki; Yoshida, Asuka

    2012-01-01

    The V protein of Sendai virus (SeV) suppresses innate immunity, resulting in enhancement of viral growth in mouse lungs and viral pathogenicity. The innate immunity restricted by the V protein is induced through activation of interferon regulatory factor 3 (IRF3). The V protein has been shown to interact with melanoma differentiation-associated gene 5 (MDA5) and to inhibit beta interferon production. In the present study, we infected MDA5-knockout mice with V-deficient SeV and found that MDA5 was largely unrelated to the innate immunity that the V protein suppresses in vivo. We therefore investigated the target of the SeV V protein. We previously reported interaction of the V protein with IRF3. Here we extended the observation and showed that the V protein appeared to inhibit translocation of IRF3 into the nucleus. We also found that the V protein inhibited IRF3 activation when induced by a constitutive active form of IRF3. The V proteins of measles virus and Newcastle disease virus inhibited IRF3 transcriptional activation, as did the V protein of SeV, while the V proteins of mumps virus and Nipah virus did not, and inhibition by these proteins correlated with interaction of each V protein with IRF3. These results indicate that IRF3 is important as an alternative target of paramyxovirus V proteins. PMID:22532687

  19. Quantitative framework for preferential flow initiation and partitioning

    USGS Publications Warehouse

    Nimmo, John R.

    2016-01-01

    A model for preferential flow in macropores is based on the short-range spatial distribution of soil matrix infiltrability. It uses elementary areas at two different scales. One is the traditional representative elementary area (REA), which includes a sufficient heterogeneity to typify larger areas, as for measuring field-scale infiltrability. The other, called an elementary matrix area (EMA), is smaller, but large enough to represent the local infiltrability of soil matrix material, between macropores. When water is applied to the land surface, each EMA absorbs water up to the rate of its matrix infiltrability. Excess water flows into a macropore, becoming preferential flow. The land surface then can be represented by a mesoscale (EMA-scale) distribution of matrix infiltrabilities. Total preferential flow at a given depth is the sum of contributions from all EMAs. Applying the model, one case study with multi-year field measurements of both preferential and diffuse fluxes at a specific depth was used to obtain parameter values by inverse calculation. The results quantify the preferential–diffuse partition of flow from individual storms that differed in rainfall amount, intensity, antecedent soil water, and other factors. Another case study provided measured values of matrix infiltrability to estimate parameter values for comparison and illustrative predictions. These examples give a self-consistent picture from the combination of parameter values, directions of sensitivities, and magnitudes of differences caused by different variables. One major practical use of this model is to calculate the dependence of preferential flow on climate-related factors, such as varying soil wetness and rainfall intensity.

  20. Inhibition of catalase activity in vitro by diesel exhaust particles

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Mori, Yoki; Murakami, Sumika; Sagae, Toshiyuki

    1996-02-09

    The effect of diesel exhaust particles (DEP) on the activity of catalase, an intracellular anti-oxidant, was investigated because H{sub 2}O{sub 2} is a cytotoxic oxidant, and catalase released from alveolar cells is an important antioxidant in the epithelial lining fluid in the lung. DEP inhibited the activity of bovine liver catalase dose-dependently, to 25-30% of its original value. The inhibition of catalase by DEP was observed only in the presence of anions such as Cl{sup {minus}}, Br{sup {minus}}, or thiocyanate. Other anions, such as CH{sub 3}COO{sup {minus}} or SO{sub 4}{sup {minus}}, and cations such as K{sup +}, Na{sup +}, Mg{supmore » 2+}, or Fe{sup 2+}, did not affect the activity of catalase, even in the presence of DEP extract. Catalase from guinea pig alveolar cells and catalase from red blood cells were also inhibited by DEP extracts, as was catalase from bovine liver. These results suggest that DEP taken up in the lung and located on alveolar spaces might cause cell injury by inhibiting the activity of catalase in epithelial lining fluid, enhancing the toxicity of H{sub 2}O{sub 2} generated from cells in addition to that of O{sub 2}{sup {minus}} generated by the chemical reaction of DEP with oxygen. 10 refs., 6 figs.« less

  1. Land cover effects on infiltration and preferential flow pathways in the high rainfall zone of Madagascar

    NASA Astrophysics Data System (ADS)

    Zwartendijk, Bob; van Meerveld, Ilja; Ravelona, Maafaka; Razakamanarivo, Herintsitohaina; Ghimire, Chandra; Bruijnzeel, Sampurno; Jones, Julia

    2015-04-01

    Shortened slash-and-burn cycles exhaust agricultural land and have resulted in extensive tracts of highly degraded land across the tropics. Land degradation typically results in decreased rainfall infiltration due to a reduced field-saturated hydraulic conductivity of the topsoil because of a progressive decline in soil organic matter, exposure to raindrop impact, surface sealing and compaction. This results, in turn, in enhanced surface runoff and erosion, and consequently less subsurface flow and groundwater recharge. On the other hand, natural vegetation regrowth or active reforestation can lead to a renewed accumulation of soil organic matter, macropore development and increased infiltration rates. As part of the P4GES project (Can Paying 4 Global Ecosystem Services values reduce poverty?; www.p4ges.org), we study the effects of land use change and reforestation on water resources in the Corridor Ankeniheny-Zahamena (CAZ) in eastern Madagascar. In this poster, we present the results of infiltration and preferential flow measurements in four different land uses in the southern part of the CAZ: (i) closed canopy forest, (ii) 3-14 year-old regrowth on fallow land (savokas), (iii) exhausted and severely degraded land (tany maty), and (iv) recently reforested sites (6-8 years old). The results show that infiltrability increases significantly after several years of forest regrowth after land abandonment, but it remains unclear whether active replanting decreases the time required for restoration of soil hydrological functioning. Preferential flow pathways differed strikingly between the respective land cover types: infiltration in mature forests was predominantly characterized by macropore flow (preferential flow pathways), whereas infiltration in exhausted agricultural land was dominated by matrix flow (few preferential flow pathways). Occurrence of preferential flow pathways in reforestation and fallow sites varied considerably. These results suggest that land

  2. Sensorimotor-Independent Prefrontal Activity During Response Inhibition

    PubMed Central

    Cai, Weidong; Cannistraci, Christopher J.; Gore, John C.; Leung, Hoi-Chung

    2015-01-01

    A network of brain regions involving the ventral inferior frontal gyrus/anterior insula (vIFG/AI), presupplementary motor area (pre-SMA) and basal ganglia has been implicated in stopping impulsive, unwanted responses. However, whether this network plays an equal role in response inhibition under different sensorimotor contexts has not been tested systematically. Here, we conducted an fMRI experiment using the stop signal task, a sensorimotor task requiring occasional withholding of the planned response upon the presentation of a stop signal. We manipulated both the sensory modality of the stop signal (visual versus auditory) and the motor response modality (hand versus eye). Results showed that the vIFG/AI and the preSMA along with the right middle frontal gyrus were commonly activated in response inhibition across the various sensorimotor conditions. Our findings provide direct evidence for a common role of these frontal areas, but not striatal areas in response inhibition independent of the sensorimotor contexts. Nevertheless, these three frontal regions exhibited different activation patterns during successful and unsuccessful stopping. Together with the existing evidence, we suggest that the vIFG/AI is involved in the early stages of stopping such as triggering the stop process while the preSMA may play a role in regulating other cortical and subcortical regions involved in stopping. PMID:23798325

  3. Striated muscle preferentially expressed genes alpha and beta are two serine/threonine protein kinases derived from the same gene as the aortic preferentially expressed gene-1.

    PubMed

    Hsieh, C M; Fukumoto, S; Layne, M D; Maemura, K; Charles, H; Patel, A; Perrella, M A; Lee, M E

    2000-11-24

    Aortic preferentially expressed gene (APEG)-1 is a 1.4-kilobase pair (kb) mRNA expressed in vascular smooth muscle cells and is down-regulated by vascular injury. An APEG-1 5'-end cDNA probe identified three additional isoforms. The 9-kb striated preferentially expressed gene (SPEG)alpha and the 11-kb SPEGbeta were found in skeletal muscle and heart. The 4-kb brain preferentially expressed gene was detected in the brain and aorta. We report here cloning of the 11-kb SPEGbeta cDNA. SPEGbeta encodes a 355-kDa protein that contains two serine/threonine kinase domains and is homologous to proteins of the myosin light chain kinase family. At least one kinase domain is active and capable of autophosphorylation. In the genome, all four isoforms share the middle three of the five exons of APEG-1, and they differ from each other by using different 5'- and 3'-ends and alternative splicing. We show that the expression of SPEGalpha and SPEGbeta is developmentally regulated in the striated muscle during C2C12 myoblast to myotube differentiation in vitro and cardiomyocyte maturation in vivo. This developmental regulation suggests that both SPEGalpha and SPEGbeta can serve as sensitive markers for striated muscle differentiation and that they may be important for adult striated muscle function.

  4. Curcumin directly inhibits the transport activity of GLUT1

    PubMed Central

    Gunnink, Leesha K.; Alabi, Ola D.; Kuiper, Benjamin D.; Gunnink, Stephen M.; Schuiteman, Sam J.; Strohbehn, Lauren E.; Hamilton, Kathryn E.; Wrobel, Kathryn E.; Louters, Larry L.

    2016-01-01

    Curcumin, a major ingredient in turmeric, has a long history of medicinal applications in a wide array of maladies including treatment for diabetes and cancer. Seemingly counterintuitive to the documented hypoglycemic effects of curcumin, however, a recent report indicates that curcumin directly inhibits glucose uptake in adipocytes. The major glucose transporter in adipocytes is GLUT4. Therefore, this study investigates the effects of curcumin in cell lines where the major transporter is GLUT1. We report that curcumin has an immediate inhibitory effect on basal glucose uptake in L929 fibroblast cells with a maximum inhibition of 80% achieved at 75 μM curcumin. Curcumin also blocks activation of glucose uptake by azide, glucose deprivation, hydroxylamine, or phenylarsine oxide. Inhibition does not increase with exposure time and the inhibitory effects reverse within an hour. Inhibition does not appear to involve a reaction between curcumin and the thiol side chain of a cysteine residue since neither prior treatment of cells with iodoacetamide nor curcumin with cysteine alters curcumin’s inhibitory effects. Curcumin is a mixed inhibitor reducing the Vmax of 2DG transport by about half with little effect on the Km. The inhibitory effects of curcumin are not additive to the effects of cytochalasin B and 75 μM curcumin actually reduces specific cytochalasin B binding by 80%. Taken together, the data suggest that curcumin binds directly to GLUT1 at a site that overlaps with the cytochalasin B binding site and thereby inhibits glucose transport. A direct inhibition of GLUT proteins in intestinal epithelial cells would likely reduce absorption of dietary glucose and contribute to a hypoglycemic effect of curcumin. Also, inhibition of GLUT1 activity might compromise cancer cells that overexpress GLUT1 and be another possible mechanism for the documented anticancer effects of curcumin. PMID:27039889

  5. Protease Activated Receptor-2 Mediates Activated Protein C–Induced Cutaneous Wound Healing via Inhibition of p38

    PubMed Central

    Julovi, Sohel M.; Xue, Meilang; Dervish, Suat; Sambrook, Philip N.; March, Lyn; Jackson, Christopher John

    2011-01-01

    Activated protein C (APC) is a natural anticoagulant that exerts anti-inflammatory and cytoprotective properties mediated through the protease activated receptor (PAR)-1. APC can also proteolytically cleave PAR-2, although subsequent function is unknown. On the basis of recent evidence that APC promotes wound healing, the aim of this study was to determine whether APC acts through PARs to heal murine excisional wounds or to regulate human cultured keratinocyte function and to determine the signaling mechanisms. Topical administration of APC accelerated wound healing in wild-type mice and, unexpectedly, in PAR-1 knockout mice. PAR-2 knockout mice healed significantly slower than wild-type mice, and healing was not altered by adding APC, indicating that APC acts through PAR-2 to heal wounds. In cultured human primary keratinocytes, APC enhanced PAR-2, stimulated proliferation, activated phosphatidylinositol 3-kinase/Src/Akt, and inhibited phosphorylated (P)-p38. Inhibiting PAR-1 or PAR-2, by small-interfering RNA or blocking antibody, reversed APC-induced keratinocyte proliferation and Akt activation. Blocking PAR-2, but not PAR-1, reversed the inhibition of P-p38 by APC. Furthermore, inhibition of P-p38 accelerated wound healing in wild-type mice. In summary, although APC acts through both PAR-1 and PAR-2 to activate Akt and to increase keratinocyte proliferation, APC-induced murine wound healing depends on PAR-2 activity and inhibition of P-p38. PMID:21907694

  6. 15 CFR 700.14 - Preferential scheduling.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) BUREAU OF INDUSTRY AND SECURITY, DEPARTMENT OF COMMERCE NATIONAL SECURITY INDUSTRIAL BASE REGULATIONS DEFENSE PRIORITIES AND ALLOCATIONS SYSTEM Industrial Priorities § 700.14 Preferential scheduling. (a) A...

  7. Inhibition of Mitogen-activated Protein Kinase (MAPK)-interacting Kinase (MNK) Preferentially Affects Translation of mRNAs Containing Both a 5'-Terminal Cap and Hairpin.

    PubMed

    Korneeva, Nadejda L; Song, Anren; Gram, Hermann; Edens, Mary Ann; Rhoads, Robert E

    2016-02-12

    The MAPK-interacting kinases 1 and 2 (MNK1 and MNK2) are activated by extracellular signal-regulated kinases 1 and 2 (ERK1/2) or p38 in response to cellular stress and extracellular stimuli that include growth factors, cytokines, and hormones. Modulation of MNK activity affects translation of mRNAs involved in the cell cycle, cancer progression, and cell survival. However, the mechanism by which MNK selectively affects translation of these mRNAs is not understood. MNK binds eukaryotic translation initiation factor 4G (eIF4G) and phosphorylates the cap-binding protein eIF4E. Using a cell-free translation system from rabbit reticulocytes programmed with mRNAs containing different 5'-ends, we show that an MNK inhibitor, CGP57380, affects translation of only those mRNAs that contain both a cap and a hairpin in the 5'-UTR. Similarly, a C-terminal fragment of human eIF4G-1, eIF4G(1357-1600), which prevents binding of MNK to intact eIF4G, reduces eIF4E phosphorylation and inhibits translation of only capped and hairpin-containing mRNAs. Analysis of proteins bound to m(7)GTP-Sepharose reveals that both CGP and eIF4G(1357-1600) decrease binding of eIF4E to eIF4G. These data suggest that MNK stimulates translation only of mRNAs containing both a cap and 5'-terminal RNA duplex via eIF4E phosphorylation, thereby enhancing the coupled cap-binding and RNA-unwinding activities of eIF4F. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. Inhibition of Human Drug Transporter Activities by the Pyrethroid Pesticides Allethrin and Tetramethrin

    PubMed Central

    Chedik, Lisa; Bruyere, Arnaud; Le Vee, Marc; Stieger, Bruno; Denizot, Claire; Parmentier, Yannick; Potin, Sophie; Fardel, Olivier

    2017-01-01

    Pyrethroids are widely-used chemical insecticides, to which humans are commonly exposed, and known to alter functional expression of drug metabolizing enzymes. Limited data have additionally suggested that drug transporters, that constitute key-actors of the drug detoxification system, may also be targeted by pyrethroids. The present study was therefore designed to analyze the potential regulatory effects of these pesticides towards activities of main ATP-binding cassette (ABC) and solute carrier (SLC) drug transporters, using transporter-overexpressing cells. The pyrethroids allethrin and tetramethrin were found to inhibit various ABC and SLC drug transporters, including multidrug resistance-associated protein (MRP) 2, breast cancer resistance protein (BCRP), organic anion transporter polypeptide (OATP) 1B1, organic anion transporter (OAT) 3, multidrug and toxin extrusion transporter (MATE) 1, organic cation transporter (OCT) 1 and OCT2, with IC50 values however ranging from 2.6 μM (OCT1 inhibition by allethrin) to 77.6 μM (OAT3 inhibition by tetramethrin) and thus much higher than pyrethroid concentrations (in the nM range) reached in environmentally pyrethroid-exposed humans. By contrast, allethrin and tetramethrin cis-stimulated OATP2B1 activity and failed to alter activities of OATP1B3, OAT1 and MATE2-K, whereas P-glycoprotein activity was additionally moderately inhibited. Twelve other pyrethoids used at 100 μM did not block activities of the various investigated transporters, or only moderately inhibited some of them (inhibition by less than 50%). In silico analysis of structure-activity relationships next revealed that molecular parameters, including molecular weight and lipophilicity, are associated with transporter inhibition by allethrin/tetramethrin and successfully predicted transporter inhibition by the pyrethroids imiprothrin and prallethrin. Taken together, these data fully demonstrated that two pyrethoids, i.e., allethrin and tetramethrin, can

  9. Dihydroartemisinin inhibits catabolism in rat chondrocytes by activating autophagy via inhibition of the NF-κB pathway

    PubMed Central

    Jiang, Li-Bo; Meng, De-Hua; Lee, Soo-Min; Liu, Shu-Hao; Xu, Qin-Tong; Wang, Yang; Zhang, Jian

    2016-01-01

    Osteoarthritis is a disease with inflammatory and catabolic imbalance in cartilage. Dihydroartemisinin (DHA), a natural and safe anti-malarial agent, has been reported to inhibit inflammation, but its effects on chondrocytes have yet to be elucidated. We investigated the effects of DHA on catabolism in chondrocytes. Viability of SD rats chondrocytes was analyzed. Autophagy levels were determined via expression of autophagic markers LC3 and ATG5, GFP-LC3 analysis, acridine orange staining, and electron microscopy. ATG5 siRNA induced autophagic inhibition. Catabolic gene and chemokine expression was evaluated using qPCR. The NF-κB inhibitor SM7368 and p65 over-expression were used to analyze the role of NF-κB pathway in autophagic activation. A concentration of 1 μM DHA without cytotoxicity increased LC3-II and ATG5 levels as well as autophagosomal numbers in chondrocytes. DHA inhibited TNF-α-induced expression of MMP-3 and -9, ADAMTS5, CCL-2 and -5, and CXCL1, which was reversed by autophagic inhibition. TNF-α-stimulated nuclear translocation and degradation of the p65 and IκBα proteins, respectively, were attenuated in DHA-treated chondrocytes. NF-κB inhibition activated autophagy in TNF-α-treated chondrocytes, but p65 over-expression reduced the autophagic response to DHA. These results indicate that DHA might suppress the levels of catabolic and inflammatory factors in chondrocytes by promoting autophagy via NF-κB pathway inhibition. PMID:27941926

  10. Direct inhibition of interleukin-2 receptor alpha-mediated signaling pathway induces G1 arrest and apoptosis in human head-and-neck cancer cells.

    PubMed

    Kuhn, Deborah J; Dou, Q Ping

    2005-05-15

    Overexpression of the interleukin-2 receptor (IL-2R) alpha chain in tumor cells is associated with tumor progression and a poor patient prognosis. IL-2Ralpha is responsible for the high affinity binding of the receptor to IL-2, leading to activation of several proliferative and anti-apoptotic intracellular signaling pathways. We have previously shown that human squamous cell carcinoma of a head-and-neck line (PCI-13) genetically engineered to overexpress IL-2Ralpha exhibit increased transforming activity, proliferation, and drug resistance, compared to the vector control cells (J Cell Biochem 2003;89:824-836). In this study, we report that IL-2Ralpha(+) cells express high levels of total and phosphorylated Jak3 protein and are more resistant to apoptosis induced by a Jak3 inhibitor than the control LacZ cells. Furthermore, we used daclizumab, a monoclonal antibody specific to IL-2Ralpha, and determined the effects of IL-2Ralpha inhibition on cell cycle and apoptosis as well as the involvement of potential cell cycle and apoptosis regulatory proteins. We found that daclizumab induces G(1) arrest, associated with down-regulation of cyclin A protein, preferentially in IL-2Ralpha(+) cells, but not in LacZ cells. In addition, daclizumab activates apoptotic death program via Bcl-2 down-regulation preferentially in IL-2Ralpha(+) cells. Finally, daclizumab also sensitizes IL-2Ralpha(+) cells to other apoptotic stimuli, although the effect is moderate. These results indicate that daclizumab inhibits the proliferative potential of IL-2Ralpha(+) cells via inhibition of cell cycle progression and induction of apoptosis.

  11. Dasatinib inhibits both osteoclast activation and prostate cancer PC-3-cell-induced osteoclast formation.

    PubMed

    Araujo, John C; Poblenz, Ann; Corn, Paul; Parikh, Nila U; Starbuck, Michael W; Thompson, Jerry T; Lee, Francis; Logothetis, Christopher J; Darnay, Bryant G

    2009-11-01

    Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC(50) of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts, and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases.

  12. Evidence that N-acetylcysteine inhibits TNF-alpha-induced cerebrovascular endothelin-1 upregulation via inhibition of mitogen- and stress-activated protein kinase.

    PubMed

    Sury, Matthias D; Frese-Schaper, Manuela; Mühlemann, Miranda K; Schulthess, Fabienne T; Blasig, Ingolf E; Täuber, Martin G; Shaw, Sidney G; Christen, Stephan

    2006-11-01

    N-acetylcysteine (NAC) is neuroprotective in animal models of acute brain injury such as caused by bacterial meningitis. However, the mechanism(s) by which NAC exerts neuroprotection is unclear. Gene expression of endothelin-1 (ET-1), which contributes to cerebral blood flow decline in acute brain injury, is partially regulated by reactive oxygen species, and thus a potential target of NAC. We therefore examined the effect of NAC on tumor necrosis factor (TNF)-alpha-induced ET-1 production in cerebrovascular endothelial cells. NAC dose dependently inhibited TNF-alpha-induced preproET-1 mRNA upregulation and ET-1 protein secretion, while upregulation of inducible nitric oxide synthase (iNOS) was unaffected. Intriguingly, NAC had no effect on the initial activation (i.e., IkappaB degradation, nuclear p65 translocation, and Ser536 phosphorylation) of NF-kappaB by TNF-alpha. However, transient inhibition of NF-kappaB DNA binding suggested that NAC may inhibit ET-1 upregulation by inhibiting (a) parallel pathway(s) necessary for full transcriptional activation of NF-kappaB-mediated ET-1 gene expression. Similar to NAC, the MEK1/2 inhibitor U0126, the p38 inhibitor SB203580, and the protein kinase inhibitor H-89 selectively inhibited ET-1 upregulation without affecting nuclear p65 translocation, suggesting that NAC inhibits ET-1 upregulation via inhibition of mitogen- and stress-activated protein kinase (MSK). Supporting this notion, cotreatment with NAC inhibited the TNF-alpha-induced rise in MSK1 and MSK2 kinase activity, while siRNA knock-down experiments showed that MSK2 is the predominant isoform involved in TNF-alpha-induced ET-1 upregulation.

  13. Rosmarinic Acid Activates AMPK to Inhibit Metastasis of Colorectal Cancer

    PubMed Central

    Han, Yo-Han; Kee, Ji-Ye; Hong, Seung-Heon

    2018-01-01

    Rosmarinic acid (RA) has been used as an anti-inflammatory, anti-diabetic, and anti-cancer agent. Although RA has also been shown to exert an anti-metastatic effect, the mechanism of this effect has not been reported to be associated with AMP-activated protein kinase (AMPK). The aim of this study was to elucidate whether RA could inhibit the metastatic properties of colorectal cancer (CRC) cells via the phosphorylation of AMPK. RA inhibited the proliferation of CRC cells through the induction of cell cycle arrest and apoptosis. In several metastatic phenotypes of CRC cells, RA regulated epithelial–mesenchymal transition (EMT) through the upregulation of an epithelial marker, E-cadherin, and the downregulation of the mesenchymal markers, N-cadherin, snail, twist, vimentin, and slug. Invasion and migration of CRC cells were inhibited and expressions of matrix metalloproteinase (MMP)-2 and MMP-9 were decreased by RA treatment. Adhesion and adhesion molecules such as ICAM-1 and integrin β1 expressions were also reduced by RA treatment. In particular, the effects of RA on EMT and MMPs expressions were due to the activation of AMPK. Moreover, RA inhibited lung metastasis of CRC cells by activating AMPK in mouse model. Collectively, these results proved that RA could be potential therapeutic agent against metastasis of CRC. PMID:29459827

  14. Osteoclast-derived microRNA-containing exosomes selectively inhibit osteoblast activity

    PubMed Central

    Sun, Weijia; Zhao, Chenyang; Li, Yuheng; Wang, Liang; Nie, Guangjun; Peng, Jiang; Wang, Aiyuan; Zhang, Pengfei; Tian, Weiming; Li, Qi; Song, Jinping; Wang, Cheng; Xu, Xiaolong; Tian, Yanhua; Zhao, Dingsheng; Xu, Zi; Zhong, Guohui; Han, Bingxing; Ling, Shukuan; Chang, Yan-Zhong; Li, Yingxian

    2016-01-01

    MicroRNAs have an important role in bone homeostasis. However, the detailed mechanism of microRNA-mediated intercellular communication between bone cells remains elusive. Here, we report that osteoclasts secrete microRNA-enriched exosomes, by which miR-214 is transferred into osteoblasts to inhibit their function. In a coculture system, inhibition of exosome formation and secretion prevented miR-214 transportation. Exosomes specifically recognized osteoblasts through the interaction between ephrinA2 and EphA2. In osteoclast-specific miR-214 transgenic mice, exosomes were secreted into the serum, and miR-214 and ephrinA2 levels were elevated. Therefore, these exosomes have an inhibitory role in osteoblast activity. miR-214 and ephrinA2 levels in serum exosomes from osteoporotic patients and mice were upregulated substantially. These exosomes may significantly inhibit osteoblast activity. Inhibition of exosome secretion via Rab27a small interfering RNA prevented ovariectomized-induced osteoblast dysfunction in vivo. Taken together, these findings suggest that exosome-mediated transfer of microRNA plays an important role in the regulation of osteoblast activity. Circulating miR-214 in exosomes not only represents a biomarker for bone loss but could selectively regulate osteoblast function. PMID:27462462

  15. Synthesis and acetylcholinesterase/butyrylcholinesterase inhibition activity of new tacrine-like analogues.

    PubMed

    Marco, J L; de los Ríos, C; Carreiras, M C; Baños, J E; Badía, A; Vivas, N M

    2001-03-01

    The synthesis and preliminary results for acetylcholinesterase and butyrylcholinesterase inhibition activity of a series of pyrano[2,3-b]quinolines (2, 3) and benzonaphthyridines (5, 6) derivatives are described. These molecules are tacrine-like analogues which have been prepared from readily available polyfunctionalized ethyl [6-amino-5-cyano-4H-pyrans and 6-amino-5-cyanopyridines]-3-carboxylates via Friedlander condensation with selected ketones. These compounds showed moderate acetylcholinesterase inhibition activity, the more potent (2e, 5b) being 6 times less active than tacrine. The butyrylcholinesterase activity of some of these molecules is also discussed.

  16. Do displacement activities help preschool children to inhibit a forbidden action?

    PubMed

    Pecora, Giulia; Addessi, Elsa; Schino, Gabriele; Bellagamba, Francesca

    2014-10-01

    Displacement activities are commonly recognized as behavioral patterns, mostly including self-directed actions (e.g., scratching, self-touching), that often occur in situations involving conflicting motivational tendencies. In ethology, several researchers have suggested that displacement activities could facilitate individuals in dealing with the stress experienced in a frustrating context. In child developmental research, some authors have assessed whether distraction strategies could help children to inhibit a dominant response during delay of gratification tasks. However, little is known about the displacement activities that young children may produce in such situations. This study was aimed at investigating whether displacement activities had an effect on preschool children's ability to postpone an immediate gratification (i.e., interacting with an attractive toy, a musical box), thereby functioning as regulators of their emotional state. To this end, we administered 143 2- to 4-year-olds with a delay maintenance task and related their performance with displacement activities they produced during the task and with actions with an external object. Children's latency to touch the musical box was positively related to their rate of displacement activities. However, the rate of displacement activities increased progressively as long as the children were able to inhibit the interaction with the musical box. In addition, the rate of displacement activities during the first 1 min of test did not predict the ability of children to inhibit the interaction with the box. These results suggest that displacement activities represented a functionless by-product of motivational conflict rather than a strategy that children used to inhibit their response to an attractive stimulus. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Antiproliferative activity of guava leaf extract via inhibition of prostaglandin endoperoxide H synthase isoforms.

    PubMed

    Kawakami, Yuki; Nakamura, Tomomi; Hosokawa, Tomoko; Suzuki-Yamamoto, Toshiko; Yamashita, Hiromi; Kimoto, Masumi; Tsuji, Hideaki; Yoshida, Hideki; Hada, Takahiko; Takahashi, Yoshitaka

    2009-01-01

    Prostaglandin endoperoxide H synthase (PGHS) is a key enzyme for the synthesis of prostaglandins (PGs) which play important roles in inflammation and carcinogenesis. Because the extract from Psidium guajava is known to have a variety of beneficial effects on our body including the anti-inflammatory, antioxidative and antiproliferative activities, we investigated whether the extract inhibited the catalytic activity of the two PGHS isoforms using linoleic acid as an alternative substrate. The guava leaf extract inhibited the cyclooxygenase reaction of recombinant human PGHS-1 and PGHS-2 as assessed by conversion of linoleic acid to 9- and 13-hydroxyoctadecadienoic acids (HODEs). The guava leaf extract also inhibited the PG hydroperoxidase activity of PGHS-1, which was not affected by nonsteroidal anti-inflammatory drugs (NSAIDs). Quercetin which was one of the major components not only inhibited the cyclooxygenase activity of both isoforms but also partially inhibited the PG hydroperoxidase activity. Overexpression of human PGHS-1 and PGHS-2 in the human colon carcinoma cells increased the DNA synthesis rate as compared with mock-transfected cells which did not express any isoforms. The guava leaf extract not only inhibited the PGE(2) synthesis but also suppressed the DNA synthesis rate in the PGHS-1- and PGHS-2-expressing cells to the same level as mock-transfected cells. These results demonstrate the antiproliferative activity of the guava leaf extract which is at least in part caused by inhibition of the catalytic activity of PGHS isoforms.

  18. Potentiation of tonic GABAergic inhibition by activation of postsynaptic kainate receptors.

    PubMed

    Jiang, L; Kang, D; Kang, J

    2015-07-09

    Presynaptic kainate-type glutamate ionotropic receptors (KARs) that mediate either the depression or the facilitation of GABA release have been intensively studied. Little attention has been given to the modulation of GABAA receptors (GABAARs) by postsynaptic KARs. Recent studies suggest that two GABAAR populations, synaptic (sGABAAR) and extrasynaptic (eGABAAR) GABAARs, mediate phasic and tonic forms of inhibition, respectively. Tonic inhibition plays an important role in the excitability of neuronal circuits and the occurrence of epileptic seizures. For this study, we are the first to report that the activation of postsynaptic KARs by the KAR agonist, Kainic acid (KA, 5 μM), enhanced tonic inhibition by potentiating eGABAARs. KA enhanced THIP-induced eGABAAR currents and prolonged the rise and decay time of muscimol-induced sGABAAR/eGABAAR currents, but also depressed the amplitude of evoked inhibitory postsynaptic currents (IPSCs), unitary IPSCs (uIPSCs), and muscimol-induced sGABAAR/eGABAAR currents. The PKC inhibitor, staurosporine (1 μM), in the patch pipette solution fully blocked the KA-induced potentiation of tonic inhibition, suggesting the involvement of an intracellular PKC pathway. Our study suggests that the activation of postsynaptic KARs potentiates eGABAARs but depresses sGABAARs. By activating postsynaptic KARs, synaptically released glutamate depresses phasic inhibition to facilitate neuronal plasticity, but potentiates tonic inhibition to protect neurons from over-excitation. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  19. Controlled CO preferential oxidation

    DOEpatents

    Meltser, Mark A.; Hoch, Martin M.

    1997-01-01

    Method for controlling the supply of air to a PROX reactor for the preferential oxidation in the presence of hydrogen wherein the concentration of the hydrogen entering and exiting the PROX reactor is monitored, the difference therebetween correlated to the amount of air needed to minimize such difference, and based thereon the air supply to the PROX reactor adjusted to provide such amount and minimize such difference.

  20. Discovering Preferential Patterns in Sectoral Trade Networks

    PubMed Central

    Cingolani, Isabella; Piccardi, Carlo; Tajoli, Lucia

    2015-01-01

    We analyze the patterns of import/export bilateral relations, with the aim of assessing the relevance and shape of “preferentiality” in countries’ trade decisions. Preferentiality here is defined as the tendency to concentrate trade on one or few partners. With this purpose, we adopt a systemic approach through the use of the tools of complex network analysis. In particular, we apply a pattern detection approach based on community and pseudocommunity analysis, in order to highlight the groups of countries within which most of members’ trade occur. The method is applied to two intra-industry trade networks consisting of 221 countries, relative to the low-tech “Textiles and Textile Articles” and the high-tech “Electronics” sectors for the year 2006, to look at the structure of world trade before the start of the international financial crisis. It turns out that the two networks display some similarities and some differences in preferential trade patterns: they both include few significant communities that define narrow sets of countries trading with each other as preferential destinations markets or supply sources, and they are characterized by the presence of similar hierarchical structures, led by the largest economies. But there are also distinctive features due to the characteristics of the industries examined, in which the organization of production and the destination markets are different. Overall, the extent of preferentiality and partner selection at the sector level confirm the relevance of international trade costs still today, inducing countries to seek the highest efficiency in their trade patterns. PMID:26485163

  1. Preferential Option for the Poor: Making a Pedagogical Choice

    ERIC Educational Resources Information Center

    Kirylo, James D.

    2006-01-01

    When children are sick, hurt, or in desperate need, parents/caregivers naturally make preferential options for them. Yet, as it relates to social justice, particularly when working with students from marginalized and poverty situations, the concept of making a preferential option in a school setting is not as clear. However, a school setting is a…

  2. GPER inhibits diabetes-mediated RhoA activation to prevent vascular endothelial dysfunction.

    PubMed

    Li, Zilin; Cheng, Liang; Liang, Hongliang; Duan, Weixun; Hu, Jing; Zhi, Weiwei; Yang, Jinbao; Liu, Zhenhua; Zhao, Minggao; Liu, Jincheng

    2016-02-01

    The effect of estrogen receptors on diabetes-induced vascular dysfunction is critical, but ambiguous. Individuals with diabetic vascular disease may require estrogen receptor-specific targeted therapy in the future. The G protein-coupled estrogen receptor (GPER) has beneficial effects on vascular function. However, its fundamental mechanisms are unclear. The RhoA/Rho-kinase pathway contributes to diabetic vascular complications, whereas estrogen can suppress Rho-kinase function. Thus, we assumed that GPER inhibits diabetes-mediated RhoA activation to prevent vascular dysfunction. We further investigated the underlying mechanisms involved in this process. Vascular endothelial cells and ex vivo cultured ovariectomized (OVX) C57BL/6 mouse aortae were treated with high glucose (HG) alone or in combination with GPER agonist (G1). G1 treatment was also administered to OVX db/db mice for 8 weeks. An ex-vivo isovolumic myograph was used to analyze the endothelium-dependent vasodilation and endothelium-independent contraction of mouse aortae. Apoptosis, oxidative stress, and inflammation were attenuated in G1-pretreated vascular endothelial cells. G1 significantly decreased the phosphorylation of inhibitory endothelial nitric oxide (NO) synthase residue threonine 495 (eNOS Thr495), inhibited RhoA expression, and increased NO production. Additionally, G1 rescued the impaired endothelium-dependent relaxation and inhibited RhoA activation in the thoracic aorta of OVX db/db mice and ex-vivo cultured OVX C57BL/6 mouse aortae treated with HG. Estrogens acting via GPER could protect vascular endothelium, and GPER activation might elicit ERα-independent effect to inhibit RhoA/Rho-kinase pathway. Additionally, GPER activation might reduce vascular smooth muscle contraction by inhibiting RhoA activation. Thus, the results of the present study suggest a new therapeutic paradigm for end-stage vascular dysfunction by inhibiting RhoA/Rho-kinase pathway via GPER activation. Copyright

  3. Nitric oxide inhibits exocytosis of cytolytic granules from lymphokine-activated killer cells

    PubMed Central

    Ferlito, Marcella; Irani, Kaikobad; Faraday, Nauder; Lowenstein, Charles J.

    2006-01-01

    NO inhibits cytotoxic T lymphocyte killing of target cells, although the precise mechanism is unknown. We hypothesized that NO decreases exocytosis of cytotoxic granules from activated lymphocytes. We now show that NO inhibits lymphokine-activated killer cell killing of K562 target cells. Exogenous and endogenous NO decreases the release of granzyme B, granzyme A, and perforin: all contents of cytotoxic granules. NO inhibits the signal transduction cascade initiated by cross-linking of the T cell receptor that leads to granule exocytosis. In particular, we found that NO decreases the expression of Ras, a critical signaling component within the exocytic pathway. Ectopic expression of Ras prevents NO inhibition of exocytosis. Our data suggest that Ras mediates NO inhibition of lymphocyte cytotoxicity and emphasize that alterations in the cellular redox state may regulate the exocytic signaling pathway. PMID:16857739

  4. AVS-1357 inhibits melanogenesis via prolonged ERK activation.

    PubMed

    Kim, Dong-Seok; Lee, Hyun-Kyung; Park, Seo-Hyoung; Chae, Chong Hak; Park, Kyoung-Chan

    2009-08-01

    In this study, we demonstrated that a derivative of imidazole, AVS-1357, is a novel skin-whitening compound. AVS-1357 was found to significantly inhibit melanin production in a dose-dependent manner; however, it did not directly inhibit tyrosinase. Furthermore, we found that AVS-1357 induced prolonged activation of extracellular signal-regulated kinase (ERK) and Akt, while it downregulated microphthalmia-associated transcription factor (MITF) and tyrosinase. It has been reported that the activation of ERK and/or Akt is involved in melanogenesis. Therefore, we examined the effects of AVS-1357 on melanogenesis in the absence or presence of PD98059 (a specific inhibitor of the ERK pathway) and/or LY294002 (a specific inhibitor of the Akt pathway). PD98059 dramatically increased melanogenesis, whereas LY294002 had no effect. Furthermore, PD98059 attenuated AVS-1357 induced ERK activation, as well as the downregulation of MITF and tyrosinase. These findings suggest that the effects of AVS-1357 occur via downregulation of MITF and tyrosinase, which is caused by AVS-1357-induced prolonged ERK activation. Taken together, our results indicate that AVS-1357 has the potential as a new skin whitening agent.

  5. Emotion potentiates response activation and inhibition in masked priming

    PubMed Central

    Bocanegra, Bruno R.; Zeelenberg, René

    2012-01-01

    Previous studies have shown that emotion can have 2-fold effects on perception. At the object-level, emotional stimuli benefit from a stimulus-specific boost in visual attention at the relative expense of competing stimuli. At the visual feature-level, recent findings indicate that emotion may inhibit the processing of small visual details and facilitate the processing of coarse visual features. In the present study, we investigated whether emotion can boost the activation and inhibition of automatic motor responses that are generated prior to overt perception. To investigate this, we tested whether an emotional cue affects covert motor responses in a masked priming task. We used a masked priming paradigm in which participants responded to target arrows that were preceded by invisible congruent or incongruent prime arrows. In the standard paradigm, participants react faster, and commit fewer errors responding to the directionality of target arrows, when they are preceded by congruent vs. incongruent masked prime arrows (positive congruency effect, PCE). However, as prime-target SOAs increase, this effect reverses (negative congruency effect, NCE). These findings have been explained as evidence for an initial activation and a subsequent inhibition of a partial response elicited by the masked prime arrow. Our results show that the presentation of fearful face cues, compared to neutral face cues, increased the size of both the PCE and NCE, despite the fact that the primes were invisible. This is the first demonstration that emotion prepares an individual's visuomotor system for automatic activation and inhibition of motor responses in the absence of visual awareness. PMID:23162447

  6. Emotion potentiates response activation and inhibition in masked priming.

    PubMed

    Bocanegra, Bruno R; Zeelenberg, René

    2012-01-01

    Previous studies have shown that emotion can have 2-fold effects on perception. At the object-level, emotional stimuli benefit from a stimulus-specific boost in visual attention at the relative expense of competing stimuli. At the visual feature-level, recent findings indicate that emotion may inhibit the processing of small visual details and facilitate the processing of coarse visual features. In the present study, we investigated whether emotion can boost the activation and inhibition of automatic motor responses that are generated prior to overt perception. To investigate this, we tested whether an emotional cue affects covert motor responses in a masked priming task. We used a masked priming paradigm in which participants responded to target arrows that were preceded by invisible congruent or incongruent prime arrows. In the standard paradigm, participants react faster, and commit fewer errors responding to the directionality of target arrows, when they are preceded by congruent vs. incongruent masked prime arrows (positive congruency effect, PCE). However, as prime-target SOAs increase, this effect reverses (negative congruency effect, NCE). These findings have been explained as evidence for an initial activation and a subsequent inhibition of a partial response elicited by the masked prime arrow. Our results show that the presentation of fearful face cues, compared to neutral face cues, increased the size of both the PCE and NCE, despite the fact that the primes were invisible. This is the first demonstration that emotion prepares an individual's visuomotor system for automatic activation and inhibition of motor responses in the absence of visual awareness.

  7. Dasatinib inhibits both osteoclast activation and prostate cancer PC-3 cell-induced osteoclast formation

    PubMed Central

    Araujo, John C.; Poblenz, Ann; Corn, Paul G.; Parikh, Nila U.; Starbuck, Michael W.; Thompson, Jerry T.; Lee, Francis; Logothetis, Christopher J.; Darnay, Bryant G.

    2013-01-01

    Purpose Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Results Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC50 of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. Experimental design We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Conclusion Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases. PMID:19855158

  8. Evaluation of the interaction between plant roots and preferential flow paths

    NASA Astrophysics Data System (ADS)

    Zhang, Yinghu; Niu, Jianzhi; Zhang, Mingxiang; Xiao, Zixing; Zhu, Weili

    2017-04-01

    Introduction Preferential flow causing environmental issues by carrying contaminants to the groundwater resources level, occurs throughout the world. Soil water flow and solute transportation via preferential flow paths with little resistance could bypass soil matrix quickly. It is necessary to characterize preferential flow phenomenon because of its understanding of ecological functions of soil, including the degradation of topsoil, the low activity of soil microorganisms, the loss of soil nutrients, and the serious source of pollution of groundwater resources (Brevik et al., 2015; Singh et al., 2015). Studies on the interaction between plant roots and soil water flow in response to preferential flow is promising increasingly. However, it is complicated to evaluate soil hydrology when plant roots are associated with the mechanisms of soil water flow and solute transportation, especially preferential flow (Ola et al., 2015). Root channels formed by living/decayed plant roots and root-soil interfaces affect soil hydrology (Tracy et al., 2011). For example, Jørgensen et al. (2002) stated that soil water flow was more obvious in soil profiles with plant roots than in soil profiles without plant roots. The present study was conducted to investigate the interaction between plant roots and soil water flow in response to preferential flow in stony soils. Materials and methods Field experiments: field dye tracing experiments centered on experimental plants (S. japonica Linn, P. orientalis (L.) Franco, and Q. dentata Thunb) were conducted to characterize the root length density, preferential flow paths (stained areas), and soil matrix (unstained areas). Brilliant Blue FCF (C.I. Food Blue 2) as dye solution (50 L) was applied to the experimental plots. Laboratory analyses: undisturbed soil columns (7-cm diameter, 10 cm high) obtained from soil depths of 0-20, 20-40, and 40-60 cm, respectively, were conducted with breakthrough curves experiments under different conditions

  9. Berberine regulates AMP-activated protein kinase signaling pathways and inhibits colon tumorigenesis in mice

    PubMed Central

    Li, Weidong; Hua, Baojin; Saud, Shakir M.; Lin, Hongsheng; Hou, Wei; Matter, Matthias S.; Jia, Libin; Colburn, Nancy H.; Young, Matthew R.

    2015-01-01

    Colorectal cancer, a leading cause of cancer death, has been linked to inflammation and obesity. Berberine, an isoquinoline alkaloid, possesses anti-inflammatory, anti-diabetes and anti-tumor properties. In the azoxymethane initiated and dextran sulfate sodium (AOM/DSS) promoted colorectal carcinogenesis mouse model, berberine treated mice showed a 60% reduction in tumor number (P=0.009), a 48% reduction in tumors <2 mm, (P=0.05); 94% reduction in tumors 2-4 mm, (P=0.001) and 100% reduction in tumors >4 mm (P=0.02) compared to vehicle treated mice. Berberine also decreased AOM/DSS induced Ki-67 and COX-2 expression. In vitro analysis showed that in addition to its anti-proliferation activity, berberine also induced apoptosis in colorectal cancer cell lines. Berberine activated AMP-activated protein kinase (AMPK), a major regulator of metabolic pathways, and inhibited mammalian target of rapamycin (mTOR), a downstream target of AMPK. Furthermore, 4E-binding protein-1 and p70 ribosomal S6 kinases, downstream targets of mTOR, were down regulated by berberine treatment. Berberine did not affect Liver kinase B1 (LKB1) activity or the mitogen-activated protein kinase pathway. Berberine inhibited Nuclear Factor kappa-B (NF-κB) activity, reduced the expression of cyclin D1 and survivin, induced phosphorylation of p53 and increased caspase-3 cleavage in vitro. Berberine inhibition of mTOR activity and p53 phosphorylation was found to be AMPK dependent, while inhibition NF-κB was AMPK independent. In vivo, berberine also activated AMPK, inhibited mTOR and p65 phosphorylation and activated caspase-3 cleavage. Our data suggests that berberine suppresses colon epithelial proliferation and tumorigenesis via AMPK dependent inhibition of mTOR activity and AMPK independent inhibition of NF-κB. PMID:24838344

  10. Novel dimeric bis(7)-tacrine proton-dependently inhibits NMDA-activated currents

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Luo, Jialie; Li, Wenming; Liu, Yuwei

    2007-09-21

    Bis(7)-tacrine has been shown to prevent glutamate-induced neuronal apoptosis by blocking NMDA receptors. However, the characteristics of the inhibition have not been fully elucidated. In this study, we further characterize the features of bis(7)-tacrine inhibition of NMDA-activated current in cultured rat hippocampal neurons. The results show that with the increase of extracellular pH, the inhibitory effect decreases dramatically. At pH 8.0, the concentration-response curve of bis(7)-tacrine is shifted rightwards with the IC{sub 50} value increased from 0.19 {+-} 0.03 {mu}M to 0.41 {+-} 0.04 {mu}M. In addition, bis(7)-tacrine shifts the proton inhibition curve rightwards. Furthermore, the inhibitory effect of bis(7)-tacrinemore » is not altered by the presence of the NMDA receptor proton sensor shield spermidine. These results indicate that bis(7)-tacrine inhibits NMDA-activated current in a pH-dependent manner by sensitizing NMDA receptors to proton inhibition, rendering it potentially beneficial therapeutic effects under acidic conditions associated with stroke and ischemia.« less

  11. Ingestion of onion soup high in quercetin inhibits platelet aggregation and essential components of the collagen-stimulated platelet activation pathway in man: a pilot study.

    PubMed

    Hubbard, Gary P; Wolffram, Siegfried; de Vos, Ric; Bovy, Arnaud; Gibbins, Jonathan M; Lovegrove, Julie A

    2006-09-01

    Epidemiological data suggest that those who consume a diet rich in quercetin-containing foods may have a reduced risk of CVD. Furthermore, in vitro and ex vivo studies have observed the inhibition of collagen-induced platelet activation by quercetin. The aim of the present study was to investigate the possible inhibitory effects of quercetin ingestion from a dietary source on collagen-stimulated platelet aggregation and signalling. A double-blind randomised cross-over pilot study was undertaken. Subjects ingested a soup containing either a high or a low amount of quercetin. Plasma quercetin concentrations and platelet aggregation and signalling were assessed after soup ingestion. The high-quercetin soup contained 69 mg total quercetin compared with the low-quercetin soup containing 5 mg total quercetin. Plasma quercetin concentrations were significantly higher after high-quercetin soup ingestion than after low-quercetin soup ingestion and peaked at 2.59 (sem 0.42) mumol/l. Collagen-stimulated (0.5 mug/ml) platelet aggregation was inhibited after ingestion of the high-quercetin soup in a time-dependent manner. Collagen-stimulated tyrosine phosphorylation of a key component of the collagen-signalling pathway via glycoprotein VI, Syk, was significantly inhibited by ingestion of the high-quercetin soup. The inhibition of Syk tyrosine phosphorylation was correlated with the area under the curve for the high-quercetin plasma profile. In conclusion, the ingestion of quercetin from a dietary source of onion soup could inhibit some aspects of collagen-stimulated platelet aggregation and signalling ex vivo. This further substantiates the epidemiological data suggesting that those who preferentially consume high amounts of quercetin-containing foods have a reduced risk of thrombosis and potential CVD risk.

  12. Inhibition of CYP1 by berberine, palmatine, and jatrorrhizine: Selectivity, kinetic characterization, and molecular modeling

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lo, Sheng-Nan; Institute of Biopharmaceutical Sciences, National Yang-Ming University, Taipei 112, Taiwan, ROC; Chang, Yu-Ping

    Cytochrome P450 (P450, CYP) 1 family plays a primary role in the detoxification and bioactivation of polycyclic aromatic hydrocarbons. Human CYP1A1, CYP1A2, and CYP1B1 exhibit differential substrate specificity and tissue distribution. Berberine, palmatine, and jatrorrhizine are protoberberine alkaloids present in several medicinal herbs, such as Coptis chinensis (Huang-Lian) and goldenseal. These protoberberines inhibited CYP1A1.1- and CYP1B1.1-catalyzed 7-ethoxyresorufin O-deethylation (EROD) activities, whereas CYP1A2.1 activity was barely affected. Kinetic analysis revealed that berberine noncompetitively inhibited EROD activities of CYP1A1.1 and CYP1B1.1, whereas palmatine and jatrorrhizine caused either competitive or mixed type of inhibition. Among protoberberines, berberine caused the most potent and selectivemore » inhibitory effect on CYP1B1.1 with the least K{sub i} value of 44 ± 16 nM. Berberine also potently inhibited CYP1B1.1 activities toward 7-ethoxycoumarin and 7-methoxyresorufin, whereas the inhibition of benzo(a)pyrene hydroxylation activity was less pronounced. Berberine inhibited the polymorphic variants, CYP1B1.3 (V432L) and CYP1B1.4 (N453S), with IC{sub 50} values comparable to that for CYP1B1.1 inhibition. Berberine-mediated inhibition was abolished by a mutation of Asn228 to Thr in CYP1B1.1, whereas the inhibition was enhanced by a reversal mutation of Thr223 to Asn in CYP1A2.1. This result in conjugation with the molecular modeling revealed the crucial role of hydrogen-bonding interaction of Asn228 on CYP1B1.1 with the methoxy moiety of berberine. These findings demonstrate that berberine causes a selective CYP1B1-inhibition, in which Asn228 appears to be crucial. The inhibitory effects of berberine on CYP1B1 activities toward structurally diverse substrates can be different. - Highlights: • Berberine preferentially inhibited CYP1B1 activity. • Berberine caused similar inhibitory effects on CYP1B1.1, CYP1B1.3 and CYP1B1.4. • Asn

  13. Screening for acetylcholinesterase inhibition and antioxidant activity of selected plants from Croatia.

    PubMed

    Jukic, Mila; Burcul, Franko; Carev, Ivana; Politeo, Olivera; Milos, Mladen

    2012-01-01

    The methanol, ethyl acetate and chloroform extracts of selected Croatian plants were tested for their acetylcholinesterase (AChE) inhibition and antioxidant activity. Assessment of AChE inhibition was carried out using microplate reader at 1 mg mL⁻¹. Antioxidant capacities were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging test and ferric reducing/antioxidant power assay (FRAP). Total phenol content (TPC) of extracts were determined using Folin-Ciocalteu colorimetric method. Out of 48 extracts, only methanolic extract of the Salix alba L. cortex exerted modest activity towards AChE, reaching 50.80% inhibition at concentration of 1 mg mL⁻¹. All the other samples tested had activity below 20%. The same extract performed the best antioxidative activity using DPPH and FRAP method, too. In essence, among all extracts used in the screening, methanolic extracts showed the best antioxidative activity as well as highest TPC.

  14. Cyclosporin a inhibits T cell-mediated augmentation of mouse natural killer activity.

    PubMed

    Yanagihara, R H; Adler, W H

    1982-06-01

    Cyclosporin A (CSA) in vitro inhibited the spontaneous cytotoxic activity of mouse spleen cells against YAC target cells in a 4 hr 51Cr release assay. While natural killer (NK) cells were inhibited directly by CSA, these suppressive effects were largely reversible by coculture of effector cells for an optimal period with polyinosinic-polycytidylic acid (Poly I:C) or lipopolysaccharide (LPS). In contrast concanavalin A (Con A), in the presence of CSA, was unable to augment NK activity. The supernatant, however, of mouse spleen cells cultured with Con A was fully able to augment the NK the activity by freshly cultured spleen cells in the presence of CSA. The results indicate that CSA inhibits NK activity by two distinct mechanisms: a) a direct inactivation of NK cells and b) a suppression of production or release of an NK-activating factor from T cells, but not B cells or macrophages.

  15. A preferential p110alpha/gamma PI3K inhibitor attenuates experimental inflammation by suppressing the production of proinflammatory mediators in a NF-kappaB-dependent manner.

    PubMed

    Dagia, Nilesh M; Agarwal, Gautam; Kamath, Divya V; Chetrapal-Kunwar, Anshu; Gupte, Ravindra D; Jadhav, Mahesh G; Dadarkar, Shruta S; Trivedi, Jacqueline; Kulkarni-Almeida, Asha A; Kharas, Firuza; Fonseca, Lyle C; Kumar, Sanjay; Bhonde, Mandar R

    2010-04-01

    A promising therapeutic approach to diminish pathological inflammation is to inhibit the increased production and/or biological activity of proinflammatory cytokines (e.g., TNF-alpha, IL-6). The production of proinflammatory cytokines is controlled at the gene level by the activity of transcription factors, such as NF-kappaB. Phosphatidylinositol 3-kinase (PI3K), a lipid kinase, is known to induce the activation of NF-kappaB. Given this, we hypothesized that inhibitors of PI3K activation would demonstrate anti-inflammatory potential. Accordingly, we studied the effects of a preferential p110alpha/gamma PI3K inhibitor (compound 8C; PIK-75) in inflammation-based assays. Mechanism-based assays utilizing human cells revealed that PIK-75-mediated inhibition of PI3K activation is associated with dramatic suppression of downstream signaling events, including AKT phosphorylation, IKK activation, and NF-kappaB transcription. Cell-based assays revealed that PIK-75 potently and dose dependently inhibits in vitro and in vivo production of TNF-alpha and IL-6, diminishes the induced expression of human endothelial cell adhesion molecules (E-selectin, ICAM-1, and VCAM-1), and blocks human monocyte-endothelial cell adhesion. Most importantly, PIK-75, when administered orally in a therapeutic regimen, significantly suppresses the macroscopic and histological abnormalities associated with dextran sulfate sodium-induced murine colitis. The efficacy of PIK-75 in attenuating experimental inflammation is mediated, at least in part, due to the downregulation of pertinent inflammatory mediators in the colon. Collectively, these results provide first evidence that PIK-75 possesses anti-inflammatory potential. Given that PIK-75 is known to exhibit anti-cancer activity, the findings from this study thus reinforce the cross-therapeutic functionality of potential drugs.

  16. Comparable cortical activation with inferior performance in women during a novel cognitive inhibition task.

    PubMed

    Halari, R; Kumari, V

    2005-03-07

    Men are hypothesised to perform better than women at tasks requiring cognitive inhibition. The present study applied whole-brain functional magnetic resonance imaging to investigate the neural correlates of cognitive inhibition using a novel task, requiring detection of numbers decreasing in numerical order, in relation to sex. The study involved 19 young healthy subjects (9 men, 10 women). Behavioural sex differences favouring men were found on the inhibition, but not on the automatization (i.e. detection of numbers increasing in numerical order), condition of the task. Significant areas of activation associated with cognitive inhibition included the right inferior prefrontal and bilateral dorsolateral prefrontal cortices, left inferior and superior parietal lobes, and bilateral temporal regions across men and women. No brain region was significantly differently activated in men and women. Our findings demonstrate that (a) cognitive inhibition is dependent on intact processes within frontal and parietal regions, and (b) women show inferior cognitive inhibition despite of comparable activation to men in relevant regions. Equated behavioural performance may elicit sex differences in brain activation.

  17. Methylisoindigo preferentially kills cancer stem cells by interfering cell metabolism via inhibition of LKB1 and activation of AMPK in PDACs.

    PubMed

    Cheng, Xinlai; Kim, Jee Young; Ghafoory, Shahrouz; Duvaci, Tijen; Rafiee, Roya; Theobald, Jannick; Alborzinia, Hamed; Holenya, Pavlo; Fredebohm, Johannes; Merz, Karl-Heinz; Mehrabi, Arianeb; Hafezi, Mohammadreza; Saffari, Arash; Eisenbrand, Gerhard; Hoheisel, Jörg D; Wölfl, Stefan

    2016-06-01

    Pancreatic ductal adenocarcinoma (PDAC) clinically has a very poor prognosis. No small molecule is available to reliably achieve cures. Meisoindigo is chemically related to the natural product indirubin and showed substantial efficiency in clinical chemotherapy for CML in China. However, its effect on PDAC is still unknown. Our results showed strong anti-proliferation effect of meisoindigo on gemcitabine-resistant PDACs. Using a recently established primary PDAC cell line, called Jopaca-1 with a larger CSCs population as model, we observed a reduction of CD133+ and ESA+/CD44+/CD24+ populations upon treatment and concomitantly a decreased expression of CSC-associated genes, and reduced cellular mobility and sphere formation. Investigating basic cellular metabolic responses, we detected lower oxygen consumption and glucose uptake, while intracellular ROS levels increased. This was effectively neutralized by the addition of antioxidants, indicating an essential role of the cellular redox balance. Further analysis on energy metabolism related signaling revealed that meisoindigo inhibited LKB1, but activated AMPK. Both of them were involved in cellular apoptosis. Additional in situ hybridization in tissue sections of PDAC patients reproducibly demonstrated co-expression and -localization of LKB1 and CD133 in malignant areas. Finally, we detected that CD133+/CD44+ were more vulnerable to meisoindigo, which could be mimicked by LKB1 siRNAs. Our results provide the first evidence, to our knowledge, that LKB1 sustains the CSC population in PDACs and demonstrate a clear benefit of meisoindigo in treatment of gemcitabine-resistant cells. This novel mechanism may provide a promising new treatment option for PDAC. Copyright © 2016 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  18. Antifreeze Protein Mimetic Metallohelices with Potent Ice Recrystallization Inhibition Activity.

    PubMed

    Mitchell, Daniel E; Clarkson, Guy; Fox, David J; Vipond, Rebecca A; Scott, Peter; Gibson, Matthew I

    2017-07-26

    Antifreeze proteins are produced by extremophile species to control ice formation and growth, and they have potential applications in many fields. There are few examples of synthetic materials which can reproduce their potent ice recrystallization inhibition property. We report that self-assembled enantiomerically pure, amphipathic metallohelicies inhibited ice growth at just 20 μM. Structure-property relationships and calculations support the hypothesis that amphipathicity is the key motif for activity. This opens up a new field of metallo-organic antifreeze protein mimetics and provides insight into the origins of ice-growth inhibition.

  19. O-sulfated bacterial polysaccharides with low anticoagulant activity inhibit metastasis.

    PubMed

    Borgenström, Marjut; Wärri, Anni; Hiilesvuo, Katri; Käkönen, Rami; Käkönen, Sanna; Nissinen, Liisa; Pihlavisto, Marjo; Marjamäki, Anne; Vlodavsky, Israel; Naggi, Annamaria; Torri, Giangiacomo; Casu, Benito; Veromaa, Timo; Salmivirta, Markku; Elenius, Klaus

    2007-07-01

    Heparin-like polysaccharides possess the capacity to inhibit cancer cell proliferation, angiogenesis, heparanase-mediated cancer cell invasion, and cancer cell adhesion to vascular endothelia via adhesion receptors, such as selectins. The clinical applicability of the antitumor effect of such polysaccharides, however, is compromised by their anticoagulant activity. We have compared the potential of chemically O-sulfated and N,O-sulfated bacterial polysaccharide (capsular polysaccharide from E. COLI K5 [K5PS]) species to inhibit metastasis of mouse B16-BL6 melanoma cells and human MDA-MB-231 breast cancer cells in two in vivo models. We demonstrate that in both settings, O-sulfated K5PS was a potent inhibitor of metastasis. Reducing the molecular weight of the polysaccharide, however, resulted in lower antimetastatic capacity. Furthermore, we show that O-sulfated K5PS efficiently inhibited the invasion of B16-BL6 cells through Matrigel and also inhibited the in vitro activity of heparanase. Moreover, treatment with O-sulfated K5PS lowered the ability of B16-BL6 cells to adhere to endothelial cells, intercellular adhesion molecule-1, and P-selectin, but not to E-selectin. Importantly, O-sulfated K5PSs were largely devoid of anticoagulant activity. These findings indicate that O-sulfated K5PS polysaccharide should be considered as a potential antimetastatic agent.

  20. Inhibition of class IIa histone deacetylase activity by gallic acid, sulforaphane, TMP269, and panobinostat.

    PubMed

    Choi, Sin Young; Kee, Hae Jin; Jin, Li; Ryu, Yuhee; Sun, Simei; Kim, Gwi Ran; Jeong, Myung Ho

    2018-05-01

    Histone deacetylase (HDAC) inhibitors are gaining increasing attention as potential therapeutics for cardiovascular diseases as well as cancer. We recently reported that the class II HDAC inhibitor, MC1568, and the phytochemical, gallic acid, lowered high blood pressure in mouse models of hypertension. We hypothesized that class II HDACs may be involved in the regulation of hypertension. The aim of this study was to determine and compare the effects of well-known HDAC inhibitors (TMP269, panobinostat, and MC1568), phytochemicals (gallic acid, sulforaphane, and piceatannol), and anti-hypertensive drugs (losartan, carvedilol, and furosemide) on activities of class IIa HDACs (HDAC4, 5, 7, and 9). The selective class IIa HDAC inhibitor, TMP269, and the pan-HDAC inhibitor, panobinostat, but not MC1568, clearly inhibited class IIa HDAC activities. Among the three phytochemicals, gallic acid showed remarkable inhibition, whereas sulforaphane presented mild inhibition of class IIa HDACs. Piceatannol inhibited only HDAC7 activity. As expected, the anti-hypertensive drugs losartan, carvedilol, and furosemide did not affect the activity of any class IIa HDAC. In addition, we evaluated the inhibitory effect of several compounds on the activity of class l HDACs (HDAC1, 2, 3, and 8) and class IIb HDAC (HDAC6). MC1568 did not affect the activities of HDAC1, HDAC2, and HDAC3, but it reduced the activity of HDAC8 at concentrations of 1 and 10 μM. Gallic acid weakly inhibited HDAC1 and HDAC6 activities, but strongly inhibited HDAC8 activity with effectiveness comparable to that of trichostatin A. Inhibition of HDAC2 activity by sulforaphane was stronger than that by piceatnnaol. These results indicated that gallic acid is a powerful dietary inhibitor of HDAC8 and class IIa/b HDAC activities. Sulforaphane may also be used as a dietary inhibitor of HDAC2 and class IIa HDAC. Our findings suggest that the class II HDAC inhibitor, MC1568, does not inhibit class IIa HDAC, but inhibits

  1. Myostatin inhibition induces muscle fibre hypertrophy prior to satellite cell activation.

    PubMed

    Wang, Qian; McPherron, Alexandra C

    2012-05-01

    Muscle fibres are multinucleated post-mitotic cells that can change dramatically in size during adulthood. It has been debated whether muscle fibre hypertrophy requires activation and fusion of muscle stem cells, the satellite cells. Myostatin (MSTN) is a negative regulator of skeletal muscle growth during development and in the adult, and MSTN inhibition is therefore a potential therapy for muscle wasting diseases, some of which are associated with a depletion of satellite cells. Conflicting results have been obtained in previous analyses of the role of MSTN on satellite cell quiescence. Here, we inhibited MSTN in adult mice with a soluble activin receptor type IIB and analysed the incorporation of new nuclei using 5-bromo-2-deoxyuridine (BrdU) labelling by isolating individual myofibres. We found that satellite cells are activated by MSTN inhibition. By varying the dose and time course for MSTN inhibition, however, we found that myofibre hypertrophy precedes the incorporation of new nuclei, and that the overall number of new nuclei is relatively low compared to the number of total myonuclei. These results reconcile some of the previous work obtained by other methods. In contrast with previous reports, we also found that Mstn null mice do not have increased satellite cell numbers during adulthood and are not resistant to sarcopaenia. Our results support a previously proposed model of hypertrophy in which hypertrophy can precede satellite cell activation. Studies of the metabolic and functional effects of postnatal MSTN inhibition are needed to determine the consequences of increasing the cytoplasm/myonuclear ratio after MSTN inhibition.

  2. 3,4-Dimethoxyphenyl bis-benzimidazole, a novel DNA topoisomerase inhibitor that preferentially targets Escherichia coli topoisomerase I

    PubMed Central

    Bansal, Sandhya; Sinha, Devapriya; Singh, Manish; Cheng, Bokun; Tse-Dinh, Yuk-Ching; Tandon, Vibha

    2012-01-01

    Objectives Antibiotic resistance in bacterial pathogens is a serious clinical problem. Novel targets are needed to combat increasing drug resistance in Escherichia coli. Our objective is to demonstrate that 2-(3,4-dimethoxyphenyl)-5-[5-(4-methylpiperazin-1-yl)-1H-benzimidazol-2yl]-1H-benzimidazole (DMA) inhibits E. coli DNA topoisomerase I more strongly than human topoisomerase I. In addition, DMA is non-toxic to mammalian cells at antibiotic dosage level. Methods In the present study, we have established DMA as an antibacterial compound by determining MICs, post-antibiotic effects (PAEs) and MBCs for different standard as well as clinical strains of E. coli. We have described the differential catalytic inhibitory mechanism of bis-benzimidazole, DMA, for human and E. coli topoisomerase I and topoisomerase II by performing different assays, including relaxation assays, cleavage–religation assays, DNA unwinding assays, ethidium bromide displacement assays, decatenation assays and DNA gyrase supercoiling assays. Results DMA significantly inhibited bacterial growth at a very low concentration, but did not affect human cell viability at higher concentrations. Activity assays showed that it preferentially targeted E. coli topoisomerase I over human topoisomerase I, topoisomerase II and gyrase. Cleavage–religation assays confirmed DMA as a poison inhibitor of E. coli topoisomerase I. This study illuminates new properties of DMA, which may be further modified to develop an efficient topoisomerase inhibitor that is selective towards bacterial topoisomerase I. Conclusions This is the first report of a bis-benzimidazole acting as an E. coli topoisomerase I inhibitor. DMA is a safe, non-cytotoxic molecule to human cells at concentrations that are needed for antibacterial activity. PMID:22945915

  3. Lactate dehydrogenase activity is inhibited by methylmalonate in vitro.

    PubMed

    Saad, Laura O; Mirandola, Sandra R; Maciel, Evelise N; Castilho, Roger F

    2006-04-01

    Methylmalonic acidemia (MMAemia) is an inherited metabolic disorder of branched amino acid and odd-chain fatty acid metabolism, involving a defect in the conversion of methylmalonyl-coenzyme A to succinyl-coenzyme A. Systemic and neurological manifestations in this disease are thought to be associated with the accumulation of methylmalonate (MMA) in tissues and biological fluids with consequent impairment of energy metabolism and oxidative stress. In the present work we studied the effect of MMA and two other inhibitors of mitochondrial respiratory chain complex II (malonate and 3-nitropropionate) on the activity of lactate dehydrogenase (LDH) in tissue homogenates from adult rats. MMA potently inhibited LDH-catalyzed conversion of lactate to pyruvate in liver and brain homogenates as well as in a purified bovine heart LDH preparation. LDH was about one order of magnitude less sensitive to inhibition by MMA when catalyzing the conversion of pyruvate to lactate. Kinetic studies on the inhibition of brain LDH indicated that MMA inhibits this enzyme competitively with lactate as a substrate (K (i)=3.02+/-0.59 mM). Malonate and 3-nitropropionate also strongly inhibited LDH-catalyzed conversion of lactate to pyruvate in brain homogenates, while no inhibition was observed by succinate or propionate, when present in concentrations of up to 25 mM. We propose that inhibition of the lactate/pyruvate conversion by MMA contributes to lactate accumulation in blood, metabolic acidemia and inhibition of gluconeogenesis observed in patients with MMAemia. Moreover, the inhibition of LDH in the central nervous system may also impair the lactate shuttle between astrocytes and neurons, compromising neuronal energy metabolism.

  4. Na+, K+-activated-ATPase inhibition in rainbow trout: A site for organochlorine pesticide toxicity?

    USGS Publications Warehouse

    Davis, Paul W.; Wedemeyer, Gary A.

    1971-01-01

    1. The Na+, K+-activated, Mg2+-dependent-ATPase enzyme system in a heavy microsomal fraction of rainbow trout (Salmo gairdneri) brain was inhibited in vitro by chlorinated hydrocarbon pesticides.2. T50 (concentration at 50 per cent inhibition) values for dicofol, endosulfan and DDT were 5 × 10−6, 3 × 10−5 and 1 × 10−4 M respectively. Similar inhibition by these pesticides occurred in kidney and gill ATPase preparations.3. An unexpected finding was a failure of the classic inhibitor, ouabain, to block the Na+, K+-activated component of ATPase activity in the gill.4. It is suggested that inhibition of ATPase activity may be a causal factor in the toxic effects of organochlorine pesticides in fishes.

  5. Oxidative stress inhibition and oxidant activity by fibrous clays.

    PubMed

    Cervini-Silva, Javiera; Nieto-Camacho, Antonio; Gómez-Vidales, Virginia

    2015-09-01

    Fibrous clays (sepiolite, palygorskite) are produced at 1.2m tonnes per year and have a wide range of industrial applications needing to replace long-fibre length asbestos. However, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the effect of sepiolite (Vallecas, Spain) and palygorskite (Torrejón El Rubio, Spain) on cell damage via oxidative stress (determined as the progress of lipid peroxidation, LP). The extent of LP was assessed using the Thiobarbituric Acid Reactive Substances assay. The oxidant activity by fibrous clays was quantified using Electron-Paramagnetic Resonance. Sepiolite and palygorskite inhibited LP, whereby corresponding IC50 values were 6557±1024 and 4250±289μgmL(-1). As evidenced by dose-response experiments LP inhibition by palygorskite was surface-controlled. Fibrous clay surfaces did not stabilize HO species, except for suspensions containing 5000μgmL(-1). A strong oxidant (or weak anti-oxidant) activity favours the inhibition of LP by fibrous clays. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. δ-Tocopherol inhibits receptor tyrosine kinase-induced AKT activation in prostate cancer cells.

    PubMed

    Wang, Hong; Hong, Jungil; Yang, Chung S

    2016-11-01

    The cancer preventive activity of vitamin E is suggested by epidemiological studies and supported by animal studies with vitamin E forms, γ-tocopherol and δ-tocopherol (δ-T). Several recent large-scale cancer prevention trials with high dose of α-tocopherol, however, yielded disappointing results. Whether vitamin E prevents or promotes cancer is a serious concern. A better understanding of the molecular mechanisms of action of the different forms of tocopherols would enhance our understanding of this topic. In this study, we demonstrated that δ-T was the most effective tocopherol form in inhibiting prostate cancer cell growth, by inducing cell cycle arrest and apoptosis. By profiling the effects of δ-T on the cell signaling using the phospho-kinase array, we found that the most inhibited target was the phosphorylation of AKT on T308. Further study on the activation of AKT by EGFR and IGFR revealed that δ-T attenuated the EGF/IGF-induced activation of AKT (via the phosphorylation of AKT on T308 induced by the activation of PIK3). Expression of dominant active PIK3 and AKT in prostate cancer cell line DU145 in which PIK3, AKT, and PTEN are wild type caused the cells to be reflectory to the inhibition of δ-T, supporting that δ-T inhibits the PIK3-mediated activation of AKT. Our data also suggest that δ-T interferes with the EGF-induced EGFR internalization, which leads to the inhibition of the receptor tyrosine kinase-dependent activation of AKT. In summary, our results revealed a novel mechanism of δ-T in inhibiting prostate cancer cell growth, supporting the cancer preventive activity δ-T. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

  7. Preferential sampling and Bayesian geostatistics: Statistical modeling and examples.

    PubMed

    Cecconi, Lorenzo; Grisotto, Laura; Catelan, Dolores; Lagazio, Corrado; Berrocal, Veronica; Biggeri, Annibale

    2016-08-01

    Preferential sampling refers to any situation in which the spatial process and the sampling locations are not stochastically independent. In this paper, we present two examples of geostatistical analysis in which the usual assumption of stochastic independence between the point process and the measurement process is violated. To account for preferential sampling, we specify a flexible and general Bayesian geostatistical model that includes a shared spatial random component. We apply the proposed model to two different case studies that allow us to highlight three different modeling and inferential aspects of geostatistical modeling under preferential sampling: (1) continuous or finite spatial sampling frame; (2) underlying causal model and relevant covariates; and (3) inferential goals related to mean prediction surface or prediction uncertainty. © The Author(s) 2016.

  8. Neuroprotection of Scutellarin is mediated by inhibition of microglial inflammatory activation.

    PubMed

    Wang, S; Wang, H; Guo, H; Kang, L; Gao, X; Hu, L

    2011-06-30

    Inhibition of microglial over-reaction and the inflammatory processes may represent a therapeutic target to alleviate the progression of neurological diseases, such as neurodegenerative diseases and stroke. Scutellarin is the major active component of Erigeron breviscapus (Vant.) Hand-Mazz, a herbal medicine in treatment of cerebrovascular diseases for a long time in the Orient. In this study, we explored the mechanisms of neuroprotection by Scutellarin, particularly its anti-inflammatory effects in microglia. We observed that Scutellarin inhibited lipopolysaccharide (LPS)-induced production of proinflammatory mediators such as nitric oxide (NO), tumor necrosis factor α (TNFα), interleukin-1β (IL-1β) and reactive oxygen species (ROS), suppressed LPS-stimulated inducible nitric oxide synthase (iNOS), TNFα, and IL-1β mRNA expression in rat primary microglia or BV-2 mouse microglial cell line. Scutellarin inhibited LPS-induced nuclear translocation and DNA binding activity of nuclear factor κB (NF-κB). It repressed the LPS-induced c-Jun N-terminal kinase (JNK) and p38 phosphorylation without affecting the activity of extracellular signal regulated kinase (ERK) mitogen-activated protein kinase. Moreover, Scutellarin also inhibited interferon-γ (IFN-γ)-induced NO production, iNOS mRNA expression and transcription factor signal transducer and activator of transcription 1α (STAT1α) activation. Concomitantly, conditioned media from Scutellarin pretreated BV-2 cells significantly reduced neurotoxicity compared with conditioned media from LPS treated alone. Together, the present study reported the anti-inflammatory activity of Scutellarin in microglial cells along with their underlying molecular mechanisms, and suggested Scutellarin might have therapeutic potential for various microglia mediated neuroinflammation. Copyright © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

  9. Spillover-mediated feedforward-inhibition functionally segregates interneuron activity

    PubMed Central

    Coddington, Luke T.; Rudolph, Stephanie; Lune, Patrick Vande; Overstreet-Wadiche, Linda; Wadiche, Jacques I.

    2013-01-01

    Summary Neurotransmitter spillover represents a form of neural transmission not restricted to morphologically defined synaptic connections. Communication between climbing fibers (CFs) and molecular layer interneurons (MLIs) in the cerebellum is mediated exclusively by glutamate spillover. Here, we show how CF stimulation functionally segregates MLIs based on their location relative to glutamate release. Excitation of MLIs that reside within the domain of spillover diffusion coordinates inhibition of MLIs outside the diffusion limit. CF excitation of MLIs is dependent on extrasynaptic NMDA receptors that enhance the spatial and temporal spread of CF signaling. Activity mediated by functionally segregated MLIs converges onto neighboring Purkinje cells (PCs) to generate a long-lasting biphasic change in inhibition. These data demonstrate how glutamate release from single CFs modulates excitability of neighboring PCs, thus expanding the influence of CFs on cerebellar cortical activity in a manner not predicted by anatomical connectivity. PMID:23707614

  10. Enantiomeric resolution of p-toluenesulfonate of valine benzyl ester by preferential crystallizaion.

    PubMed

    Munegumi, Toratane; Wakatsuki, Aiko; Takahashi, Yutaro

    2012-02-01

    Preferential crystallization of amino acid derivatives by seeding a pure enantiomer into racemic amino acid solutions has been studied for many years. However, few examples of valine derivatives have been reported so far. Although there have been some reports using valine hydrogen chloride with preferential crystallization, it is difficult to obtain optical isomers for valine derivatives using preferential crystallization. In this study, repeated preferential crystallization of p-toluenesulfonate valine benzyl ester with a 20% e.e. in 2-propanol gave a 94% e.e. on sonication. Sonication accelerated crystallization rate, but there was not a big difference in e.e. between with and without sonication. However, this research demonstrates the first preferential crystallization of p-toluenesulfonate of valine benzyl esters with an acceleration of crystallization using sonication. Copyright © 2011 Wiley Periodicals, Inc.

  11. Dehydration-induced modulation of κ-opioid inhibition of vasopressin neurone activity

    PubMed Central

    Scott, Victoria; Bishop, Valerie R; Leng, Gareth; Brown, Colin H

    2009-01-01

    Dehydration increases vasopressin (antidiuretic hormone) secretion from the posterior pituitary gland to reduce water loss in the urine. Vasopressin secretion is determined by action potential firing in vasopressin neurones, which can exhibit continuous, phasic (alternating periods of activity and silence), or irregular activity. Autocrine κ-opioid inhibition contributes to the generation of activity patterning of vasopressin neurones under basal conditions and so we used in vivo extracellular single unit recording to test the hypothesis that changes in autocrine κ-opioid inhibition drive changes in activity patterning of vasopressin neurones during dehydration. Dehydration increased the firing rate of rat vasopressin neurones displaying continuous activity (from 7.1 ± 0.5 to 9.0 ± 0.6 spikes s−1) and phasic activity (from 4.2 ± 0.7 to 7.8 ± 0.9 spikes s−1), but not those displaying irregular activity. The dehydration-induced increase in phasic activity was via an increase in intraburst firing rate. The selective κ-opioid receptor antagonist nor-binaltorphimine increased the firing rate of phasic neurones in non-dehydrated rats (from 3.4 ± 0.8 to 5.3 ± 0.6 spikes s−1) and dehydrated rats (from 6.4 ± 0.5 to 9.1 ± 1.2 spikes s−1), indicating that κ-opioid feedback inhibition of phasic bursts is maintained during dehydration. In a separate series of experiments, prodynorphin mRNA expression was increased in vasopressin neurones of hyperosmotic rats, compared to hypo-osmotic rats. Hence, it appears that dynorphin expression in vasopressin neurones undergoes dynamic changes in proportion to the required secretion of vasopressin so that, even under stimulated conditions, autocrine feedback inhibition of vasopressin neurones prevents over-excitation. PMID:19822541

  12. Costunolide inhibits proinflammatory cytokines and iNOS in activated murine BV2 microglia.

    PubMed

    Rayan, Nirmala Arul; Baby, Nimmi; Pitchai, Daisy; Indraswari, Fransisca; Ling, Eng-Ang; Lu, Jia; Dheen, Thameem

    2011-06-01

    Costunolide, a sesquiterpene lactone present in Costus speciosus root exerts a variety of pharmacological activity but its effects on neuroinflammation have not been studied. Microglia, the resident phagocytic cells in the central nervous system respond to neuroinflammation and their overwhelming response in turn aggravate brain damage during infection, ischemia and neurodegenerative diseases. In this study, we report the effect of Costunolide on the production of proinflammatory mediators and mechanisms involved in BV2 microglial cells stimulated with LPS. Costunolide attenuated the expression of tumour necrosis factor-alpha, interleukin-1,6, inducible nitric oxide synthase, monocyte chemotactic protein 1 and cyclooxygenase 2 in activated microglia. This Costunolide-mediated inhibition was correspondent with the inhibition of NFkappaB activation. It has been further shown that Costunolide suppressed MAPK pathway activation by inducing MKP-1 production. Collectively our results suggest that Costunolide shows an ability to inhibit expression of multiple neuroinflammatory mediators and this is attributable to the compounds inhibition of NFkappaB and MAPK activation. This novel role of Costunolide upon investigation may aid in developing better therapeutic strategies for treatment of neuroinflammatory diseases.

  13. Phenytoin preferentially inhibits L-type calcium currents in whole-cell patch-clamped cardiac and skeletal muscle cells.

    PubMed

    Rivet, M; Bois, P; Cognard, C; Raymond, G

    1990-10-01

    The effect of the anticonvulsant diphenylhydantoin (phenytoin) was tested on the inward calcium currents of whole-cell patch-clamped cells from rat and human muscles and from frog atrium. A concentration of 10 microM phenytoin was required to obtain a threshold inhibitory effect and, even with high concentrations (100 microM), the inhibition was not complete. In skeletal muscle (rat and human cells in culture), phenytoin (30 microM) exerted a more potent effect on the high-threshold calcium current (ICa,L inhibition: 53 +/- 6% mean +/- SDn-1) rather than on the low-threshold one (ICa,T inhibition: 16 +/- 10%). Similar results were obtained on dissociated frog atrial cells. These data are to be contrasted with those previously reported on neuronal cells, where specific inhibition of ICa,T was reported. Thus, the action of phenytoin appears to be different in muscle and nerve so that phenytoin does not appear to be a specific inhibitor of ICa,T.

  14. Lidocaine preferentially inhibits the function of purinergic P2X7 receptors expressed in Xenopus oocytes.

    PubMed

    Okura, Dan; Horishita, Takafumi; Ueno, Susumu; Yanagihara, Nobuyuki; Sudo, Yuka; Uezono, Yasuhito; Minami, Tomoko; Kawasaki, Takashi; Sata, Takeyoshi

    2015-03-01

    Lidocaine has been widely used to relieve acute pain and chronic refractory pain effectively by both systemic and local administration. Numerous studies reported that lidocaine affects several pain signaling pathways as well as voltage-gated sodium channels, suggesting the existence of multiple mechanisms underlying pain relief by lidocaine. Some extracellular adenosine triphosphate (ATP) receptor subunits are thought to play a role in chronic pain mechanisms, but there have been few studies on the effects of lidocaine on ATP receptors. We studied the effects of lidocaine on purinergic P2X3, P2X4, and P2X7 receptors to explore the mechanisms underlying pain-relieving effects of lidocaine. We investigated the effects of lidocaine on ATP-induced currents in ATP receptor subunits, P2X3, P2X4, and P2X7 expressed in Xenopus oocytes, by using whole-cell, two-electrode, voltage-clamp techniques. Lidocaine inhibited ATP-induced currents in P2X7, but not in P2X3 or P2X4 subunits, in a concentration-dependent manner. The half maximal inhibitory concentration for lidocaine inhibition was 282 ± 45 μmol/L. By contrast, mepivacaine, ropivacaine, and bupivacaine exerted only limited effects on the P2X7 receptor. Lidocaine inhibited the ATP concentration-response curve for the P2X7 receptor via noncompetitive inhibition. Intracellular and extracellular N-(2,6-dimethylphenylcarbamoylmethyl) triethylammonium bromide (QX-314) and benzocaine suppressed ATP-induced currents in the P2X7 receptor in a concentration-dependent manner. In addition, repetitive ATP treatments at 5-minute intervals in the continuous presence of lidocaine revealed that lidocaine inhibition was use-dependent. Finally, the selective P2X7 receptor antagonists Brilliant Blue G and AZ11645373 did not affect the inhibitory actions of lidocaine on the P2X7 receptor. Lidocaine selectively inhibited the function of the P2X7 receptor expressed in Xenopus oocytes. This effect may be caused by acting on sites in the ion

  15. Fluoxetine Prevents Oligodendrocyte Cell Death by Inhibiting Microglia Activation after Spinal Cord Injury

    PubMed Central

    Lee, Jee Y.; Kang, So R.

    2015-01-01

    Abstract Oligodendrocyte cell death and axon demyelination after spinal cord injury (SCI) are known to be important secondary injuries contributing to permanent neurological disability. Thus, blocking oligodendrocyte cell death should be considered for therapeutic intervention after SCI. Here, we demonstrated that fluoxetine, an antidepressant drug, alleviates oligodendrocyte cell death by inhibiting microglia activation after SCI. After injury at the T9 level with a Precision Systems and Instrumentation (Lexington, KY) device, fluoxetine (10 mg/kg, intraperitoneal) was administered once a day for the indicated time points. Immunostaining with CD11b (OX-42) antibody and quantification analysis showed that microglia activation was significantly inhibited by fluoxetine at 5 days after injury. Fluoxetine also significantly inhibited activation of p38 mitogen-activated protein kinase (p38-MAPK) and expression of pro-nerve growth factor (pro-NGF), which is known to mediate oligodendrocyte cell death through the p75 neurotrophin receptor after SCI. In addition, fluoxetine attenuated activation of Ras homolog gene family member A and decreased the level of phosphorylated c-Jun and, ultimately, alleviated caspase-3 activation and significantly reduced cell death of oligodendrocytes at 5 days after SCI. Further, the decrease of myelin basic protein, myelin loss, and axon loss in white matter was also significantly blocked by fluoxetine, as compared to vehicle control. These results suggest that fluoxetine inhibits oligodendrocyte cell death by inhibiting microglia activation and p38-MAPK activation, followed by pro-NGF production after SCI, and provide a potential usage of fluoxetine for a therapeutic agent after acute SCI in humans. PMID:25366938

  16. Preferential Cyclooxygenase 2 Inhibitors as a Nonhormonal Method of Emergency Contraception: A Look at the Evidence.

    PubMed

    Weiss, Erich A; Gandhi, Mona

    2016-04-01

    To review the literature surrounding the use of preferential cyclooxygenase 2 (COX-2) inhibitors as an alternative form of emergency contraception. MEDLINE (1950 to February 2014) was searched using the key words cyclooxygenase or COX-2 combined with contraception, emergency contraception, or ovulation. Results were limited to randomized control trials, controlled clinical trials, and clinical trials. Human trials that measured the effects of COX inhibition on female reproductive potential were included for review. The effects of the COX-2 inhibitors rofecoxib, celecoxib, and meloxicam were evaluated in 6 trials. Each of which was small in scope, enrolled women of variable fertility status, used different dosing regimens, included multiple end points, and had variable results. Insufficient evidence exists to fully support the use of preferential COX-2 inhibitors as a form of emergency contraception. Although all trials resulted in a decrease in ovulatory cycles, outcomes varied between dosing strategies and agents used. A lack of homogeneity in these studies makes comparisons difficult. However, success of meloxicam in multiple trials warrants further study. Larger human trials are necessary before the clinical utility of this method of emergency contraception can be fully appreciated. © The Author(s) 2014.

  17. Trace element inhibition of phytase activity.

    PubMed

    Santos, T; Connolly, C; Murphy, R

    2015-02-01

    Nowadays, 70 % of global monogastric feeds contains an exogenous phytase. Phytase supplementation has enabled a more efficient utilisation of phytate phosphorous (P) and reduction of P pollution. Trace minerals, such as iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) are essential for maintaining health and immunity as well as being involved in animal growth, production and reproduction. Exogenous sources of phytase and trace elements are regularly supplemented to monogastric diets and usually combined in a premix. However, the possibility for negative interaction between individual components within the premix is high and is often overlooked. Therefore, this initial study focused on assessing the potential in vitro interaction between inorganic and organic chelated sources of Fe, Zn, Cu and Mn with three commercially available phytase preparations. Additionally, this study has investigated if the degree of enzyme inhibition was dependent of the type of chelated sources. A highly significant relationship between phytase inhibition, trace mineral type as well as mineral source and concentration, p < 0.001 was verified. The proteinate sources of OTMs were consistently and significantly less inhibitory than the majority of the other sources, p < 0.05. This was verified for Escherichia coli and Peniophora lycii phytases for Fe and Zn, as well as for Cu with E. coli and Aspergillus niger phytases. Different chelate trace mineral sources demonstrated diversifying abilities to inhibit exogenous phytase activity.

  18. Licochalcones extracted from Glycyrrhiza inflata inhibit platelet aggregation accompanied by inhibition of COX-1 activity

    PubMed Central

    Okuda-Tanino, Asa; Sugawara, Daiki; Tashiro, Takumi; Iwashita, Masaya; Obara, Yutaro; Moriya, Takahiro; Tsushima, Chisato; Saigusa, Daisuke; Tomioka, Yoshihisa; Ishii, Kuniaki; Nakahata, Norimichi

    2017-01-01

    Licochalcones extracted from Glycyrrhiza inflata are known to have a variety of biological properties such as anti-inflammatory, anti-bacterial, and anti-tumor activities, but their action on platelet aggregation has not yet been reported. Therefore, in this study we investigated the effects of licochalcones on platelet aggregation. Collagen and U46619, a thromboxane A2 receptor agonist, caused rabbit platelet aggregation, which was reversed by pretreatment with licochalcones A, C and D in concentration-dependent manners. Among these compounds, licochalcone A caused the most potent inhibitory effect on collagen-induced platelet aggregation. However, the licochalcones showed marginal inhibitory effects on thrombin or ADP-induced platelet aggregation. In addition to rabbit platelets, licochalcone A attenuated collagen-induced aggregation in human platelets. Because licochalcone A also inhibited arachidonic acid-induced platelet aggregation and production of thromboxane A2 induced by collagen in intact platelets, we further examined the direct interaction of licochalcone A with cyclooxygenase (COX)-1. As expected, licochalcone A caused an inhibitory effect on both COX-1 and COX-2 in vitro. Regarding the effect of licochalcone A on COX-1 enzyme reaction kinetics, although licochalcone A showed a stronger inhibition of prostaglandin E2 synthesis induced by lower concentrations of arachidonic acid, Vmax values in the presence or absence of licochalcone A were comparable, suggesting that it competes with arachidonic acid at the same binding site on COX-1. These results suggest that licochalcones inhibit collagen-induced platelet aggregation accompanied by inhibition of COX-1 activity. PMID:28282426

  19. An in vitro approach to potential methadone metabolic-inhibition interactions.

    PubMed

    Bomsien, Stephanie; Skopp, Gisela

    2007-09-01

    The aim of this study was to assess the drug interaction potential of psychotropic medication on methadone N-demethylation using cDNA-expressed cytochrome P450 CYP enzymes. Methadone was incubated with various drugs (n = 10) and cDNA-expressed CYP3A4, CYP2D6, CYP2B6, CYP2C19 and CYP1A2 enzymes to screen for their inhibition potency. The nature of enzyme selective activity for inhibition was further investigated for potent inhibitors. To test for a mechanism-based component in inhibition, all substances were tested with preincubation and without. 2-Ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) concentration was determined by liquid chromatography/tandem mass spectrometry following liquid/liquid extraction. Formation of EDDP was catalysed by CYP3A4, CYP2D6 and CYP2C19. The N-demethylation of methadone was preferentially inhibited by amitriptyline, buprenorphine, methylenedioxymethamphetamine (MDMA) and zolpidem. Both amitriptyline and buprenorphine were strong, reversible inhibitors of CYP3A4. Similarly, amitriptyline and MDMA were identified as inhibitors of CYP2D6. Zolpidem revealed a mechanism-based inhibition of CYP3A4. Amitriptyline, MDMA and zolpidem are likely to slow down conversion of methadone and to increase its area under the curve (AUC). A consideration of the in vitro evidence of drug-methadone interactions should help to improve patient care during methadone maintenance treatment.

  20. BLM and RMI1 alleviate RPA inhibition of TopoIIIα decatenase activity.

    PubMed

    Yang, Jay; Bachrati, Csanad Z; Hickson, Ian D; Brown, Grant W

    2012-01-01

    RPA is a single-stranded DNA binding protein that physically associates with the BLM complex. RPA stimulates BLM helicase activity as well as the double Holliday junction dissolution activity of the BLM-topoisomerase IIIα complex. We investigated the effect of RPA on the ssDNA decatenase activity of topoisomerase IIIα. We found that RPA and other ssDNA binding proteins inhibit decatenation by topoisomerase IIIα. Complex formation between BLM, TopoIIIα, and RMI1 ablates inhibition of decatenation by ssDNA binding proteins. Together, these data indicate that inhibition by RPA does not involve species-specific interactions between RPA and BLM-TopoIIIα-RMI1, which contrasts with RPA modulation of double Holliday junction dissolution. We propose that topoisomerase IIIα and RPA compete to bind to single-stranded regions of catenanes. Interactions with BLM and RMI1 enhance toposiomerase IIIα activity, promoting decatenation in the presence of RPA.

  1. 6-Shogaol inhibits chondrocytes' innate immune responses and cathepsin-K activity.

    PubMed

    Villalvilla, Amanda; da Silva, Jame's A; Largo, Raquel; Gualillo, Oreste; Vieira, Paulo Cezar; Herrero-Beaumont, Gabriel; Gómez, Rodolfo

    2014-02-01

    Ginger has long been used in traditional Asian medicine to treat osteoarthritis. Indeed, scientific research has reported that ginger derivatives (GDs) have the potential to control innate immune responses. Given the widespread use and demonstrated properties of GDs, we set out to study their anti-inflammatory and anticatabolic properties in chondrocytes. 6-shogaol (6-S), the most active GD, was obtained from ginger. 6-S was not toxic as measured by MTT assay, and inhibited NO production and IL-6 and MCP-1 induced gene expression in LPSbut not in IL-1β-stimulated chondrocytes. 6-S also inhibited LPS-mediated ERK1/2 activation as well as NOS2 and MyD88 induced expression as determined by Western blot. Moreover, zymography revealed that 6-S inhibited matrix metalloproteinases (MMP) 2/9 induction in LPS-treated cells. Hydrated 6-S was modified to obtain a compound (SSi6) without 6-S potential anti-inflammatory properties. Both 6-S and SSi6 inhibited cathepsin-K activity. 6-S blocked TLR4-mediated innate immune responses and MMP induction in chondrocytes. These results, together with GDs-mediated cathepsin-K inhibition, suggest the potential for GDs use against cartilage and bone degradation. Therefore, considering that clinical trials involving oral administration of ginger achieved relevant nontoxic GDs serum concentrations, we suggest that a ginger-supplemented diet might reduce OA symptoms. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Current challenges in quantifying preferential flow through the vadose zone

    NASA Astrophysics Data System (ADS)

    Koestel, John; Larsbo, Mats; Jarvis, Nick

    2017-04-01

    In this presentation, we give an overview of current challenges in quantifying preferential flow through the vadose zone. A review of the literature suggests that current generation models do not fully reflect the present state of process understanding and empirical knowledge of preferential flow. We believe that the development of improved models will be stimulated by the increasingly widespread application of novel imaging technologies as well as future advances in computational power and numerical techniques. One of the main challenges in this respect is to bridge the large gap between the scales at which preferential flow occurs (pore to Darcy scales) and the scale of interest for management (fields, catchments, regions). Studies at the pore scale are being supported by the development of 3-D non-invasive imaging and numerical simulation techniques. These studies are leading to a better understanding of how macropore network topology and initial/boundary conditions control key state variables like matric potential and thus the strength of preferential flow. Extrapolation of this knowledge to larger scales would require support from theoretical frameworks such as key concepts from percolation and network theory, since we lack measurement technologies to quantify macropore networks at these large scales. Linked hydro-geophysical measurement techniques that produce highly spatially and temporally resolved data enable investigation of the larger-scale heterogeneities that can generate preferential flow patterns at pedon, hillslope and field scales. At larger regional and global scales, improved methods of data-mining and analyses of large datasets (machine learning) may help in parameterizing models as well as lead to new insights into the relationships between soil susceptibility to preferential flow and site attributes (climate, land uses, soil types).

  3. TIS21/(BTG2) negatively regulates estradiol-stimulated expansion of hematopoietic stem cells by derepressing Akt phosphorylation and inhibiting mTOR signal transduction.

    PubMed

    Kim, Bong Cho; Ryu, Min Sook; Oh, S Paul; Lim, In Kyoung

    2008-09-01

    It has been known that 12-O-tetradecanoyl phorbol-13-acetate-inducible sequence 21 (TIS21), ortholog of human B-cell translocation gene 2, regulates expansions of stage-specific thymocytes and hematopoietic progenitors. In the present study, lineage-negative (Lin(-))/stem cell antigen-1-positive (Sca-1+)/c-Kit+ (LSK) cell content was significantly elevated in bone marrow (BM) of TIS21-knockout (TIS21(-/-)) female mice, suggesting 17beta-estradiol (E(2))-regulated progenitor expansion. E(2) induced DNA synthesis and cell proliferation of mouse embryonic fibroblasts (MEFs) isolated from TIS21(-/-) mice, but not wild type (WT). In contrast to WT, E(2) failed to activate protein kinase B (Akt) in the TIS21(-/-) MEFs, independent of extracellular signal-regulated kinase 1/2 (Erk1/2) activation. Despite attenuation of Akt activation, mammalian target of rapamycin (mTOR) was constitutively activated in the TIS21(-/-) MEFs. Furthermore, mitogen-activated protein kinase 1/2 inhibitor or knockdown of Erk1 could restore activation of Akt and downregulate mTOR. Immunoprecipitation showed Akt preferentially bound to phosphorylated Erk1/2 (p-Erk1/2) in TIS21(-/-) cells, but reconstitution of TIS21 inhibited their interaction. E(2)-injected TIS21(-/-) male mice also increased LSK cells in BM. Taken together, expansion of hematopoietic progenitors in TIS21(-/-) female mice might be through inhibition of Akt activation, and constitutive activation of mTOR via preferential binding of TIS21 to E(2)-induced p-Erk1/2, compared with that of Akt. Our results suggest that TIS21 plays a pivotal role in maintaining the hematopoietic stem cell compartment and hematopoiesis.

  4. Plumbagin inhibits cytokinesis in Bacillus subtilis by inhibiting FtsZ assembly--a mechanistic study of its antibacterial activity.

    PubMed

    Bhattacharya, Anusri; Jindal, Bhavya; Singh, Parminder; Datta, Anindya; Panda, Dulal

    2013-09-01

    The assembly of FtsZ plays a central role in construction of the cytokinetic Z-ring that orchestrates bacterial cell division. A naturally occurring naphthoquinone, plumbagin, is known to exhibit antibacterial properties against several types of bacteria. In this study, plumbagin was found to perturb formation of the Z-ring in Bacillus subtilis 168 cells and to cause elongation of these cells without an apparent effect on nucleoid segregation, indicating that it may inhibit FtsZ assembly. Furthermore, it bound to purified B. subtilis FtsZ (BsFtsZ) with a dissociation constant of 20.7 ± 5.6 μM, and inhibited the assembly and GTPase activity of BsFtsZ in vitro. Interestingly, plumbagin did not inhibit either the assembly or GTPase activity of Escherichia coli FtsZ (EcFtsZ) in vitro. Using docking analysis, a putative plumbagin-binding site on BsFtsZ was identified, and the analysis indicated that hydrophobic interactions and hydrogen bonds predominate. Based on the in silico analysis, two variants of BsFtsZ, namely D199A and V307R, were constructed to explore the binding interaction of plumbagin and BsFtsZ. The effects of plumbagin on the assembly and GTPase activity of the variant BsFtsZ proteins in vitro indicated that the residues D199 and V307 may be involved in the binding of plumbagin to BsFtsZ. The results suggest that plumbagin inhibits bacterial proliferation by inhibiting the assembly of FtsZ, and provide insight into the binding site of plumbagin on BsFtsZ, which may help in the design of potent FtsZ-targeted antibacterial agents. © 2013 FEBS.

  5. Joint estimation of preferential attachment and node fitness in growing complex networks

    NASA Astrophysics Data System (ADS)

    Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

    2016-09-01

    Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit.

  6. Joint estimation of preferential attachment and node fitness in growing complex networks

    PubMed Central

    Pham, Thong; Sheridan, Paul; Shimodaira, Hidetoshi

    2016-01-01

    Complex network growth across diverse fields of science is hypothesized to be driven in the main by a combination of preferential attachment and node fitness processes. For measuring the respective influences of these processes, previous approaches make strong and untested assumptions on the functional forms of either the preferential attachment function or fitness function or both. We introduce a Bayesian statistical method called PAFit to estimate preferential attachment and node fitness without imposing such functional constraints that works by maximizing a log-likelihood function with suitably added regularization terms. We use PAFit to investigate the interplay between preferential attachment and node fitness processes in a Facebook wall-post network. While we uncover evidence for both preferential attachment and node fitness, thus validating the hypothesis that these processes together drive complex network evolution, we also find that node fitness plays the bigger role in determining the degree of a node. This is the first validation of its kind on real-world network data. But surprisingly the rate of preferential attachment is found to deviate from the conventional log-linear form when node fitness is taken into account. The proposed method is implemented in the R package PAFit. PMID:27601314

  7. Large-scale filament formation inhibits the activity of CTP synthetase

    PubMed Central

    Barry, Rachael M; Bitbol, Anne-Florence; Lorestani, Alexander; Charles, Emeric J; Habrian, Chris H; Hansen, Jesse M; Li, Hsin-Jung; Baldwin, Enoch P; Wingreen, Ned S; Kollman, Justin M; Gitai, Zemer

    2014-01-01

    CTP Synthetase (CtpS) is a universally conserved and essential metabolic enzyme. While many enzymes form small oligomers, CtpS forms large-scale filamentous structures of unknown function in prokaryotes and eukaryotes. By simultaneously monitoring CtpS polymerization and enzymatic activity, we show that polymerization inhibits activity, and CtpS's product, CTP, induces assembly. To understand how assembly inhibits activity, we used electron microscopy to define the structure of CtpS polymers. This structure suggests that polymerization sterically hinders a conformational change necessary for CtpS activity. Structure-guided mutagenesis and mathematical modeling further indicate that coupling activity to polymerization promotes cooperative catalytic regulation. This previously uncharacterized regulatory mechanism is important for cellular function since a mutant that disrupts CtpS polymerization disrupts E. coli growth and metabolic regulation without reducing CTP levels. We propose that regulation by large-scale polymerization enables ultrasensitive control of enzymatic activity while storing an enzyme subpopulation in a conformationally restricted form that is readily activatable. DOI: http://dx.doi.org/10.7554/eLife.03638.001 PMID:25030911

  8. Menthol Inhibits Detrusor Contractility Independently of TRPM8 Activation

    PubMed Central

    Ramos-Filho, Antonio Celso Saragossa; Shah, Ajay; Augusto, Taize Machado; Barbosa, Guilherme Oliveira; Leiria, Luiz Osorio; de Carvalho, Hernandes Faustino; Antunes, Edson; Grant, Andrew Douglas

    2014-01-01

    Agonists such as icilin and menthol can activate the cool temperature-sensitive ion channel TRPM8. However, biological responses to menthol may occur independently of TRPM8 activation. In the rodent urinary bladder, menthol facilitates the micturition reflex but inhibits muscarinic contractions of the detrusor smooth muscle. The site(s) of TRPM8 expression in the bladder are controversial. In this study we investigated the regulation of bladder contractility in vitro by menthol. Bladder strips from wild type and TRPM8 knockout male mice (25–30 g) were dissected free and mounted in organ baths. Isometric contractions to carbachol (1 nM–30 µM), CaCl2 (1 µM to 100 mM) and electrical field stimulation (EFS; 8, 16, 32 Hz) were measured. Strips from both groups contracted similarly in response to both carbachol and EFS. Menthol (300 µM) or nifedipine (1 µM) inhibited carbachol and EFS-induced contractions in both wild type and TRPM8 knockout bladder strips. Incubation with the sodium channel blocker tetrodotoxin (1 µM), replacement of extracellular sodium with the impermeant cation N-Methyl-D-Glucamine, incubation with a cocktail of potassium channel inhibitors (100 nM charybdotoxin, 1 µM apamin, 10 µM glibenclamide and 1 µM tetraethylammonium) or removal of the urothelium did not affect the inhibitory actions of menthol. Contraction to CaCl2 was markedly inhibited by either menthol or nifedipine. In cultured bladder smooth muscle cells, menthol or nifedipine abrogated the carbachol or KCl-induced increases in [Ca2+]i. Intravesical administration of menthol increased voiding frequency while decreasing peak voiding pressure. We conclude that menthol inhibits muscarinic bladder contractions through blockade of L-type calcium channels, independently of TRPM8 activation. PMID:25375115

  9. Sulforaphane inhibits the engagement of LPS with TLR4/MD2 complex by preferential binding to Cys133 in MD2.

    PubMed

    Koo, Jung Eun; Park, Zee-Yong; Kim, Nam Doo; Lee, Joo Young

    2013-05-10

    Toll-like receptors (TLRs) are key pattern-recognition receptors that recognize invading pathogens and non-microbial endogenous molecules to induce innate and adaptive immune responses. Since activation of TLRs is deeply implicated in the pathological progress of autoimmune diseases, sepsis, metabolic diseases, and cancer, modulation of TLR activity is considered one of the most important therapeutic approaches. Lipopolysaccharide (LPS), an endotoxin of gram-negative bacteria, is a well-known agonist for TLR4 triggering inflammation and septic shock. LPS interacts with TLR4 through binding to a hydrophobic pocket in myeloid differentiation 2 (MD2), a co-receptor of TLR4. In this study, we showed that sulforaphane (SFN) interfered with the binding of LPS to MD2 as determined by in vitro binding assay and co-immunoprecipitation of MD2 and LPS in a cell system. The inhibitory effect of SFN on the interaction of LPS and MD2 was reversed by thiol supplementation with N-acetyl-L-cysteine or dithiothreitol showing that the inhibitory effect of SFN is dependent on its thiol-modifying activity. Indeed, micro LC-MS/MS analysis showed that SFN preferentially formed adducts with Cys133 in the hydrophobic pocket of MD2, but not with Cys95 and Cys105. Molecular modeling showed that SFN bound to Cys133 blocks the engagement of LPS and lipid IVa to hydrophobic pocket of MD2. Our results demonstrate that SFN interrupts LPS engagement to TLR4/MD2 complex by direct binding to Cys133 in MD2. Our data suggest a novel mechanism for the anti-inflammatory activity of SFN, and provide a novel target for the regulation of TLR4-mediated inflammatory and immune responses by phytochemicals. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Insulin-mediated inhibition of p38 mitogen-activated protein kinase protects cardiomyocytes in severe burns.

    PubMed

    Lv, Gen-fa; Dong, Mao-long; Hu, Da-hai; Zhang, Wan-fu; Wang, Yun-chuan; Tang, Chao-wu; Zhu, Xiong-xiang

    2011-01-01

    Thermal injury inhibits Akt activation and upregulates p38 mitogen-activated protein kinase, which in turn induces inflammation and increases apoptosis. This study aimed to elucidate the mechanism underlying the cytoprotective role of insulin in severe burns by examining the effects of insulin on inflammation and apoptosis mediated by p38 mitogen-activated protein kinase in burn serum-challenged cardiomyocytes. Neonatal rat cardiomyocytes were exposed to burn serum for 6 hours in the presence or absence of insulin and pretreated with inhibitors to p38 mitogen-activated protein kinase (SB203580) and Akt (LY294002). The authors examined expression of myocardial tumor necrosis factor-alpha, cardiac myofilament proteins caspase-3 and Bcl2, and apoptosis. Burn serum-induced upregulation of tumor necrosis factor was inhibited by both SB203580 and insulin. LY294002 reversed insulin-mediated downregulation of tumor necrosis factor. Both SB203580 and insulin inhibited apoptosis, resulting in fewer pyknotic nuclei and inhibition of caspase-3 activation and Bcl2 downregulation. LY294002 reversed insulin-mediated inhibition of apoptosis. Insulin decreases inflammatory cytokine expression and apoptosis via PI3K/Akt-mediated inhibition of p38 mitogen-activated protein kinase. The cytoprotective role of insulin suggests that it may have a potential role in strategies for treating thermal injuries.

  11. Neural Activation during Inhibition Predicts Initiation of Substance Use in Adolescence

    PubMed Central

    Norman, Andria L.; Pulido, Carmen; Squeglia, Lindsay M.; Spadoni, Andrea D.; Paulus, Martin P.; Tapert, Susan F.

    2011-01-01

    Background Problems inhibiting non-adaptive behaviors have been linked to an increased risk for substance use and other risk taking behaviors in adolescence. This study examines the hypothesis that abnormalities in neural activation during inhibition in early adolescence may predict subsequent substance involvement. Methods Thirty eight adolescents from local area middle schools, ages 12–14, with very limited histories of substance use, underwent functional magnetic resonance imaging (fMRI) as they performed a go/no-go task of response inhibition and response selection. Adolescents and their parents were then followed annually with interviews covering substance use and other behaviors. Based on follow-up data, youth were classified as transitioning to heavy use of alcohol (TU; n=21), or as healthy controls (CON; n=17). Results At baseline, prior to the onset of use, youth who later transitioned into heavy use of alcohol showed significantly less activation than those who went on to remain non to minimal users throughout adolescence. Activation reductions in TU at baseline were seen on no-go trials in 12 brain regions, including right inferior frontal gyrus, left dorsal and medial frontal areas, bilateral motor cortex, cingulate gyrus, left putamen, bilateral middle temporal gyri, and bilateral inferior parietal lobules (corrected p < .01, each cluster ≥ 32 contiguous voxels). Conclusions These results support the hypothesis that less neural activity during response inhibition demands predicts future involvement with problem behaviors such as alcohol and other substance use. PMID:21782354

  12. Platelet-derived growth factor inhibits platelet activation in heparinized whole blood.

    PubMed

    Selheim, F; Holmsen, H; Vassbotn, F S

    1999-08-15

    We previously have demonstrated that human platelets have functionally active platelet-derived growth factor alpha-receptors. Studies with gel-filtered platelets showed that an autocrine inhibition pathway is transduced through this tyrosine kinase receptor during platelet activation. The physiological significance of this inhibitory effect of platelet-derived growth factor on gel-filtered platelets activation is, however, not known. In the present study, we investigated whether platelet-derived growth factor inhibits platelet activation under more physiological conditions in heparinized whole blood, which represents a more physiological condition than gel-filtered platelets. Using flow cytometric assays, we demonstrate here that platelet-derived growth factor inhibits thrombin-, thrombin receptor agonist peptide SFLLRN-, and collagen-induced platelet aggregation and shedding of platelet-derived microparticles from the platelet plasma membrane during platelet aggregation in stirred heparinized whole blood. The inhibitory effect of platelet-derived growth factor was dose dependent. However, under nonaggregating conditions (no stirring), we could not demonstrate any significant effect of platelet-derived growth factor on thrombin- and thrombin receptor agonist peptide-induced platelet surface expression of P-selectin. Our results demonstrate that platelet-derived growth factor appears to be a true antithrombotic agent only under aggregating conditions in heparinized whole blood.

  13. Investigating biological activity spectrum for novel quinoline analogues 2: hydroxyquinolinecarboxamides with photosynthesis-inhibiting activity.

    PubMed

    Musiol, Robert; Tabak, Dominik; Niedbala, Halina; Podeszwa, Barbara; Jampilek, Josef; Kralova, Katarina; Dohnal, Jiri; Finster, Jacek; Mencel, Agnieszka; Polanski, Jaroslaw

    2008-04-15

    Two series of amides based on quinoline scaffold were designed and synthesized in search of photosynthesis inhibitors. The compounds were tested for their photosynthesis-inhibiting activity against Spinacia oleracea L. and Chlorella vulgaris Beij. The compounds lipophilicity was determined by the RP-HPLC method. Several compounds showed biological activity similar or even higher than that of the standard (DCMU). The structure-activity relationships are discussed.

  14. Cyanide does more to inhibit heme enzymes, than merely serving as an active-site ligand

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Parashar, Abhinav; Venkatachalam, Avanthika; Gideon, Daniel Andrew

    Highlights: • Cyanide (CN) is a well-studied toxic principle, known to inhibit heme-enzymes. • Inhibition is supposed to result from CN binding at the active site as a ligand. • Diverse heme enzymes’ CN inhibition profiles challenge prevailing mechanism. • Poor binding efficiency of CN at low enzyme concentrations and ligand pressures. • CN-based diffusible radicals cause ‘non-productive electron transfers’ (inhibition). - Abstract: The toxicity of cyanide is hitherto attributed to its ability to bind to heme proteins’ active site and thereby inhibit their activity. It is shown herein that the long-held interpretation is inadequate to explain several observations inmore » heme-enzyme reaction systems. Generation of cyanide-based diffusible radicals in heme-enzyme reaction milieu could shunt electron transfers (by non-active site processes), and thus be detrimental to the efficiency of oxidative outcomes.« less

  15. Spreading dynamics of an e-commerce preferential information model on scale-free networks

    NASA Astrophysics Data System (ADS)

    Wan, Chen; Li, Tao; Guan, Zhi-Hong; Wang, Yuanmei; Liu, Xiongding

    2017-02-01

    In order to study the influence of the preferential degree and the heterogeneity of underlying networks on the spread of preferential e-commerce information, we propose a novel susceptible-infected-beneficial model based on scale-free networks. The spreading dynamics of the preferential information are analyzed in detail using the mean-field theory. We determine the basic reproductive number and equilibria. The theoretical analysis indicates that the basic reproductive number depends mainly on the preferential degree and the topology of the underlying networks. We prove the global stability of the information-elimination equilibrium. The permanence of preferential information and the global attractivity of the information-prevailing equilibrium are also studied in detail. Some numerical simulations are presented to verify the theoretical results.

  16. Movement Activation and Inhibition in Parkinson’s Disease: a Functional Imaging Study

    PubMed Central

    Disbrow, E. A.; Sigvardt, K. A.; Franz, E. A.; Turner, R. S.; Russo, K. A.; Hinkley, L.B.; Herron, T. J.; Ventura, M. I.; Zhang, L.; Malhado-Chang, N.

    2015-01-01

    Background Parkinson’s disease (PD), traditionally considered a movement disorder, has been shown to affect executive function such as the ability to adapt behavior in response to new environmental situations. Objective to identify the impact of PD on neural substrates subserving two specific components of normal movement which we refer to as activation (initiating an un-cued response) and inhibition (suppressing a cued response). Methods We used fMRI to measure pre-movement processes associated with activating an un-cued response and inhibiting a cued response plan in 13 PD (ON anti-parkinsonian medications) and 13 control subjects. Subjects were shown a visual arrow cue followed by a matched or mismatched response target that instructed them to respond with a right, left, or bilateral button press. In mismatched trials, an un-cued (new) response was initiated, or the previously cued response was suppressed. Results We were able to isolate pre-movement responses in dorsolateral prefrontal cortex, specifically in the right hemisphere. During the activation of an un-cued movement, PD subjects showed decreased activity in the putamen and increased cortical activity in bilateral DLPFC, SMA, subcentral gyrus and inferior frontal operculum. During inhibition of a previously cued movement, the PD group showed increased activation in SMA, S1/M1, premotor and superior parietal areas. Conclusion Right DLPFC plays a role in pre-movement processes, and DLPFC activity is abnormal in PD. Decreased specificity of responses was observed in multiple ROI’s. The basal ganglia are involved in circuits that coordinate activation and inhibition involved in action selection as well as execution. PMID:23938347

  17. Protease activity, localization and inhibition in the human hair follicle.

    PubMed

    Bhogal, R K; Mouser, P E; Higgins, C A; Turner, G A

    2014-02-01

    In humans, the process of hair shedding, referred to as exogen, is believed to occur independently of the other hair cycle phases. Although the actual mechanisms involved in hair shedding are not fully known, it has been hypothesized that the processes leading to the final step of hair shedding may be driven by proteases and/or protease inhibitor activity. In this study, we investigated the presence of proteases and protease activity in naturally shed human hairs and assessed enzyme inhibition activity of test materials. We measured enzyme activity using a fluorescence-based assay and protein localization by indirect immunohistochemistry (IHC). We also developed an ex vivo skin model for measuring the force required to pull hair fibres from skin. Our data demonstrate the presence of protease activity in the tissue material surrounding club roots. We also demonstrated the localization of specific serine protease protein expression in human hair follicle by IHC. These data provide evidence demonstrating the presence of proteases around the hair club roots, which may play a role during exogen. We further tested the hypothesis that a novel protease inhibitor system (combination of Trichogen) and climbazole) could inhibit protease activity in hair fibre club root extracts collected from a range of ethnic groups (U.K., Brazil, China, first-generation Mexicans in the U.S.A., Thailand and Turkey) in both males and females. Furthermore, we demonstrated that this combination is capable of increasing the force required to remove hair in an ex vivo skin model system. These studies indicate the presence of proteolytic activity in the tissue surrounding the human hair club root and show that it is possible to inhibit this activity with a combination of Trichogen and climbazole. This technology may have potential to reduce excessive hair shedding. © 2013 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  18. Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers

    PubMed Central

    Ohayo-Mitoko, G.; Kromhout, H.; Simwa, J.; Boleij, J.; Heederik, D.

    2000-01-01

    OBJECTIVES—This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased.
METHODS—Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum.
RESULTS—Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly >1 for respiratory, eye, and central nervous system symptoms for workers with >30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity.
CONCLUSION—The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom

  19. In situ TEM observation of preferential amorphization in single crystal Si nanowire

    NASA Astrophysics Data System (ADS)

    Su, Jiangbin; Zhu, Xianfang

    2018-06-01

    The nanoinstability of a single crystal Si nanowire under electron beam irradiation was in situ investigated at room temperature by the transmission electron microscopy technique. It was observed that the Si nanowire amorphized preferentially from the surface towards the center, with the increasing of the electron dose. In contrast, in the center of the Si nanowire the amorphization seemed much more difficult, being accompanied by the rotation of crystal grains and the compression of d-spacing. Such a preferential amorphization, which is athermally induced by the electron beam irradiation, can be well accounted for by our proposed concepts of the nanocurvature effect and the energetic beam-induced athermal activation effect, while the classical knock-on mechanism and the electron beam heating effect seem inadequate to explain these processes. Furthermore, the findings revealed the difference of amorphization between a Si nanowire and a Si film under electron beam irradiation. Also, the findings have important implications for the nanoinstability and nanoprocessing of future Si nanowire-based devices.

  20. In situ TEM observation of preferential amorphization in single crystal Si nanowire.

    PubMed

    Su, Jiangbin; Zhu, Xianfang

    2018-06-08

    The nanoinstability of a single crystal Si nanowire under electron beam irradiation was in situ investigated at room temperature by the transmission electron microscopy technique. It was observed that the Si nanowire amorphized preferentially from the surface towards the center, with the increasing of the electron dose. In contrast, in the center of the Si nanowire the amorphization seemed much more difficult, being accompanied by the rotation of crystal grains and the compression of d-spacing. Such a preferential amorphization, which is athermally induced by the electron beam irradiation, can be well accounted for by our proposed concepts of the nanocurvature effect and the energetic beam-induced athermal activation effect, while the classical knock-on mechanism and the electron beam heating effect seem inadequate to explain these processes. Furthermore, the findings revealed the difference of amorphization between a Si nanowire and a Si film under electron beam irradiation. Also, the findings have important implications for the nanoinstability and nanoprocessing of future Si nanowire-based devices.

  1. Self reported symptoms and inhibition of acetylcholinesterase activity among Kenyan agricultural workers.

    PubMed

    Ohayo-Mitoko, G J; Kromhout, H; Simwa, J M; Boleij, J S; Heederik, D

    2000-03-01

    This study was part of the East African pesticides project. The general objective was to assess health hazards posed by handling, storage, and use of pesticides, on agricultural estates and small farms with a view to developing strategies for prevention and control of pesticide poisoning. The aim of this paper is to describe the prevalence of symptoms in this population, to relate levels of inhibition to reported symptoms and evaluate at which levels of inhibition symptoms become increased. Complete data were available for 256 exposed subjects and 152 controls from four regions in Kenya. A structured questionnaire on symptoms experienced at the time of interview was given to all subjects and controls. Information was also obtained on sex, age, main occupation, and level of education. Symptoms reported during the high exposure period, were initially clustered in broader symptom categories from reference literature on health effects of pesticides that inhibit cholinesterase (organophosphate and carbamate). Prevalence ratios were estimated for symptoms with changes in cholinesterase activity in serum. Symptom prevalence in exposed subjects was higher during the high exposure period than the low exposure period, although these differences were not significant. Interestingly, a clear and significant change in symptoms prevalence was found in the controls with a higher prevalence in the low exposure period. Analysis of the relation between cholinesterase inhibition and symptoms showed that prevalence ratios were significantly > 1 for respiratory, eye, and central nervous system symptoms for workers with > 30% inhibition. Similar results were found for analyses with the actual level of acetylcholinesterase activity. The results suggest the presence of a relation between exposure and acetylcholinesterase inhibition, acetylcholinesterase activity, and respiratory, eye, and central nervous system symptoms. Increased symptom prevalence was found at acetylcholinesterase

  2. Tanshinone IIA inhibits cervix carcinoma stem cells migration and invasion via inhibiting YAP transcriptional activity.

    PubMed

    Qin, Jinghao; Shi, Hongbing; Xu, Yanjie; Zhao, Fang; Wang, Qing

    2018-06-14

    This study aims to explore the effects and related mechanisms of Tanshinone IIA in cervix carcinoma (CC) stemness-like cells migration, invasion, stemness and chemotherapeutical sensitivity. Here, we found that Tanshinone IIA suppressed CC stemness-like cells migration and invasion in a concentration- and time-dependent manner. And consistent results were obtained in CC cells stemness characterized as the decrease of CC stemness markers expression and cells spheroid formation ability. Mechanistically, we found that Tanshinone IIA suppressed RNA binding protein HuR translocation from nuclear to cytoplasm, and thus reduced YAP mRNAs stability and transcriptional activity. Importantly, overexpression YAP-5SA rescued the inhibition of Tanshinone IIA on CC cells stemness. Furthermore, Tanshinone IIA enhanced adriamycin sensitivity in CC stemness-like cells, this effect was attenuated by YAP-5SA overexpression too. Therefore, Tanshinone IIA could suppress CC stemness-like cells migration and invasion by inhibiting YAP transcriptional activity. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  3. Raloxifene increases prefrontal activity during emotional inhibition in schizophrenia based on estrogen receptor genotype.

    PubMed

    Kindler, Jochen; Weickert, Cynthia Shannon; Schofield, Peter R; Lenroot, Rhoshel; Weickert, Thomas W

    2016-12-01

    People with schizophrenia show decreased prefrontal cortex (PFC) activity during emotional response inhibition, a cognitive process sensitive to hormonal influences. Raloxifene, a selective estrogen receptor modulator, binds estrogen receptor alpha (ESR-α), improves memory, attention and normalizes cortical and hippocampal activity during learning and emotional face recognition in schizophrenia. Here, we tested the extent to which raloxifene restores neuronal activity during emotional response inhibition in schizophrenia. Since genetic variation in estrogen receptor alpha (ESR-1) determines cortical ESR-α production and correlates with cognition, we also predicted that genetic ESR-1 variation would differentially relate to increased cortical activity by raloxifene administration. Thirty people with schizophrenia participated in a thirteen-week randomized, double-blind, placebo-controlled, cross-over adjunctive treatment trial of raloxifene administered at 120mg/day. Effects of raloxifene on brain activation were assessed based on ESR-1 genotype using functional magnetic resonance imaging during emotional word inhibition. Raloxifene increased PFC activity during inhibition of response to negative words and the raloxifene related increased PFC activity was greater in patients homozygous for ESR-1 rs9340799 AA relative to G carriers. Comparison to 23 healthy controls demonstrated that PFC activity of people with schizophrenia receiving raloxifene was more similar to controls than to their own brain activity during placebo. Estrogen receptor modulation by raloxifene restores PFC activity during emotional response inhibition in schizophrenia and ESR-1 genotype predicts degree of increased neural activity in response to raloxifene. While these preliminary results require replication, they suggest the potential for personalized pharmacotherapy using ESR-1 and estrogen receptor targeting compounds in schizophrenia. Crown Copyright © 2016. Published by Elsevier B

  4. Milk Inhibits the Biological Activity of Ricin

    PubMed Central

    Rasooly, Reuven; He, Xiaohua; Friedman, Mendel

    2012-01-01

    Ricin is a highly toxic protein produced by the castor plant Ricinus communis. The toxin is relatively easy to isolate and can be used as a biological weapon. There is great interest in identifying effective inhibitors for ricin. In this study, we demonstrated by three independent assays that a component of reconstituted powdered milk has a high binding affinity to ricin. We discovered that milk can competitively bind to and reduce the amount of toxin available to asialofetuin type II, which is used as a model to study the binding of ricin to galactose cell-surface receptors. Milk also removes ricin bound to the microtiter plate. In parallel experiments, we demonstrated by activity assay and by immuno-PCR that milk can bind competitively to 1 ng/ml ricin, reducing the amount of toxin uptake by the cells, and thus inhibit the biological activity of ricin. The inhibitory effect of milk on ricin activity in Vero cells was at the same level as by anti-ricin antibodies. We also found that (a) milk did not inhibit ricin at concentrations of 10 or 100 ng/ml; (b) autoclaving 10 and 100 ng/ml ricin in DMEM at 121 °C for 30 min completely abolished activity; and (c) milk did not affect the activity of another ribosome inactivating protein, Shiga toxin type 2 (Stx2), produced by pathogenic Escherichia coli O157:H7. Unlike ricin, which is internalized into the cells via a galactose-binding site, Stx2 is internalized through the cell surface receptor glycolipid globotriasylceramides Gb3 and Gb4. These observations suggest that ricin toxicity may possibly be reduced at room temperature by a widely consumed natural liquid food. PMID:22733821

  5. Synthetic secoisolariciresinol diglucoside (LGM2605) inhibits myeloperoxidase activity in inflammatory cells.

    PubMed

    Mishra, Om P; Popov, Anatoliy V; Pietrofesa, Ralph A; Nakamaru-Ogiso, Eiko; Andrake, Mark; Christofidou-Solomidou, Melpo

    2018-06-01

    Myeloperoxidase (MPO) generates hypochlorous acid (HOCl) during inflammation and infection. We showed that secoisolariciresinol diglucoside (SDG) scavenges radiation-induced HOCl in physiological solutions. However, the action of SDG and its synthetic version, LGM2605, on MPO-catalyzed generation of HOCl is unknown. The present study evaluated the effect of LGM2605 on human MPO, and murine MPO from macrophages and neutrophils. MPO activity was determined fluorometrically using hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF). The effect of LGM2605 on (a) the peroxidase cycle of MPO was determined using Amplex Red while the effect on (b) the chlorination cycle was determined using a taurine chloramine assay. Using electron paramagnetic resonance (EPR) spectroscopy we determined the effect of LGM2605 on the EPR signals of MPO. Finally, computational docking of SDG was used to identify energetically favorable docking poses to enzyme's active site. LGM2605 inhibited human and murine MPO activity. MPO inhibition was observed in the absence and presence of Cl - . EPR confirmed that LGM2605 suppressed the formation of Compound I, an oxoiron (IV) intermediate [Fe(IV)O] containing a porphyrin π-radical of MPO's catalytic cycle. Computational docking revealed that SDG can act as an inhibitor by binding to the enzyme's active site. We conclude that LGM2605 inhibits MPO activity by suppressing both the peroxidase and chlorination cycles. EPR analysis demonstrated that LGM2605 inhibits MPO by decreasing the formation of the highly oxidative Compound I. This study identifies a novel mechanism of LGM2605 action as an inhibitor of MPO and indicates that LGM2605 may be a promising attenuator of oxidant-dependent inflammatory tissue damage. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Protease-Activated Receptor 2 Activation Inhibits N-Type Ca2+ Currents in Rat Peripheral Sympathetic Neurons

    PubMed Central

    Kim, Young-Hwan; Ahn, Duck-Sun; Kim, Myeong Ok; Joeng, Ji-Hyun; Chung, Seungsoo

    2014-01-01

    The protease-activated receptor (PAR)-2 is highly expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although several mechanisms have been suggested to explain PAR-2-induced hypotension, the precise mechanism remains to be elucidated. To investigate this possibility, we investigated the effects of PAR-2 activation on N-type Ca2+ currents (ICa-N) in isolated neurons of the celiac ganglion (CG), which is involved in the sympathetic regulation of mesenteric artery vascular tone. PAR-2 agonists irreversibly diminished voltage-gated Ca2+ currents (ICa), measured using the patch-clamp method, in rat CG neurons, whereas thrombin had little effect on ICa. This PAR-2-induced inhibition was almost completely prevented by ω-CgTx, a potent N-type Ca2+ channel blocker, suggesting the involvement of N-type Ca2+ channels in PAR-2-induced inhibition. In addition, PAR-2 agonists inhibited ICa–N in a voltage-independent manner in rat CG neurons. Moreover, PAR-2 agonists reduced action potential (AP) firing frequency as measured using the current-clamp method in rat CG neurons. This inhibition of AP firing induced by PAR-2 agonists was almost completely prevented by ω-CgTx, indicating that PAR-2 activation may regulate the membrane excitability of peripheral sympathetic neurons through modulation of N-type Ca2+ channels. In conclusion, the present findings demonstrate that the activation of PAR-2 suppresses peripheral sympathetic outflow by modulating N-type Ca2+ channel activity, which appears to be involved in PAR-2-induced hypotension, in peripheral sympathetic nerve terminals. PMID:25410909

  7. Artemisinin Inhibits Chloroplast Electron Transport Activity: Mode of Action

    PubMed Central

    Bharati, Adyasha; Kar, Monaranjan; Sabat, Surendra Chandra

    2012-01-01

    Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo), behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the QB; the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth. PMID:22719995

  8. Attention and attribute overlap in preferential choice.

    PubMed

    Bhatia, Sudeep

    2017-07-01

    Attributes that are common, or overlapping, across alternatives in two-alternative forced preferential choice tasks are often non-diagnostic. In many settings, attending to and evaluating these attributes does not help the decision maker determine which of the available alternatives is the most desirable. For this reason, many existing behavioural theories propose that decision makers ignore common attributes while deliberating. Across six experiments, we find that decision makers do direct their attention selectively and ignore attributes that are not present in or associated with either of the available alternatives. However, they are as likely to attend to common attributes as they are to attend to attributes that are unique to a single alternative. These results suggest the need for novel theories of attention in preferential choice.

  9. Preferential flow estimates to an agricultural tile drain with implications for glyphosate transport

    USGS Publications Warehouse

    Stone, W.W.; Wilson, J.T.

    2006-01-01

    Agricultural subsurface drains, commonly referred to as tile drains, are potentially significant pathways for the movement of fertilizers and pesticides to streams and ditches in much of the Midwest. Preferential flow in the unsaturated zone provides a route for water and solutes to bypass the soil matrix and reach tile drains faster than predicted by traditional displacement theory. This paper uses chloride concentrations to estimate preferential flow contributions to a tile drain during two storms in May 2004. Chloride, a conservative anion, was selected as the tracer because of differences in chloride concentrations between the two sources of water to the tile drain, preferential and matrix flow. A strong correlation between specific conductance and chloride concentration provided a mechanism to estimate chloride concentrations in the tile drain throughout the storm hydrographs. A simple mixing analysis was used to identify the preferential flow component of the storm hydrograph. During two storms, preferential flow contributed 11 and 51% of total storm tile drain flow; the peak contributions, 40 and 81%, coincided with the peak tile drain flow. Positive relations between glyphosate [N-(phosphonomethyl)glycine] concentrations and preferential flow for the two storms suggest that preferential flow is an important transport pathway to the tile drain. ?? ASA, CSSA, SSSA.

  10. Enhancement of hypoxia-activated prodrug TH-302 anti-tumor activity by Chk1 inhibition.

    PubMed

    Meng, Fanying; Bhupathi, Deepthi; Sun, Jessica D; Liu, Qian; Ahluwalia, Dharmendra; Wang, Yan; Matteucci, Mark D; Hart, Charles P

    2015-05-21

    The hypoxia-activated prodrug TH-302 is reduced at its nitroimidazole group and selectively under hypoxic conditions releases the DNA cross-linker bromo-isophosphoramide mustard (Br-IPM). Here, we have explored the effect of Chk1 inhibition on TH-302-mediated pharmacological activities. We employed in vitro cell viability, DNA damage, cellular signaling assays and the in vivo HT29 human tumor xenograft model to study the effect of Chk1inhibition on TH-302 antitumor activities. TH-302 cytotoxicity is greatly enhanced by Chk1 inhibition in p53-deficient but not in p53-proficient human cancer cell lines. Chk1 inhibitors reduced TH-302-induced cell cycle arrest via blocking TH-302-induced decrease of phosphorylation of histone H3 and increasing Cdc2-Y15 phosphorylation. Employing the single-cell gel electrophoresis (comet) assay, we observed a potentiation of the TH-302 dependent tail moment. TH-302 induced γH2AX and apoptosis were also increased upon the addition of Chk1 inhibitor. Potentiation of TH-302 cytotoxicity by Chk1 inhibitor was only observed in cell lines proficient in, but not deficient in homology-directed DNA repair. We also show that combination treatment led to lowering of Rad51 expression levels as compared to either agent alone. In vivo data demonstrate that Chk1 inhibitor enhances TH-302 anti-tumor activity in p53 mutant HT-29 human tumor xenografts, supporting the hypothesis that these in vitro results can translate to enhanced in vivo efficacy of the combination. TH-302-mediated in vitro and in vivo anti-tumor activities were greatly enhanced by the addition of Chk1 inhibitors. The preclinical data presented in this study support a new approach for the treatment of p53-deficient hypoxic cancers by combining Chk1 inhibitors with the hypoxia-activated prodrug TH-302.

  11. Inhibition of Protease-Activated Receptor (PAR1) Reduces Activation of the Endothelium, Coagulation, Fibrinolysis and Inflammation during Human Endotoxemia.

    PubMed

    Schoergenhofer, Christian; Schwameis, Michael; Gelbenegger, Georg; Buchtele, Nina; Thaler, Barbara; Mussbacher, Marion; Schabbauer, Gernot; Wojta, Johann; Jilma-Stohlawetz, Petra; Jilma, Bernd

    2018-06-04

    The protease-activated receptor-1 (PAR-1) is critically involved in the co-activation of coagulation and inflammatory responses. Vorapaxar is a reversible, orally active, low molecular weight, competitive antagonist of PAR-1.We investigated the effects of PAR-1 inhibition by vorapaxar on the inflammatory response, the activation of coagulation, fibrinolysis and endothelium during experimental endotoxemia. In this randomized, double blind, crossover trial, 16 healthy volunteers received a bolus infusion of 2 ng/kg lipopolysaccharide (LPS) ± placebo/vorapaxar with a washout period of 8 weeks. Vorapaxar dosing was guided by thrombin receptor-activating peptide-6-induced whole blood aggregometry. Participants received 10 mg vorapaxar or placebo as an initial dose and, depending on the aggregometry, potentially an additional 10 mg. Goal was > 80% inhibition of aggregation compared with baseline. Vorapaxar significantly reduced the LPS-induced increase in pro-thrombin fragments F1 + 2 by a median of 27% (quartiles: 11-49%), thrombin-anti-thrombin concentrations by 22% (-3 to 46%) and plasmin-anti-plasmin levels by 38% (23-53%). PAR-1 inhibition dampened peak concentrations of tumour necrosis factor -α, interleukin-6 and consequently C-reactive protein by 66% (-11-71%), 50% (15-79%) and 23% (16-38%), respectively. Vorapaxar decreased maximum von Willebrand factor levels by 29% (26-51%) and soluble E-selectin concentrations by 30% (25-38%) after LPS infusion. PAR-1 inhibition did not affect thrombomodulin, soluble P-selectin and platelet factor-4 concentrations.PAR-1 inhibition significantly reduced the activation of coagulation, fibrinolysis, the inflammatory response and endothelial activation during experimental human endotoxemia. Schattauer GmbH Stuttgart.

  12. Effect of mitochondrial complex I inhibition on Fe-S cluster protein activity.

    PubMed

    Mena, Natalia P; Bulteau, Anne Laure; Salazar, Julio; Hirsch, Etienne C; Núñez, Marco T

    2011-06-03

    Iron-sulfur (Fe-S) clusters are small inorganic cofactors formed by tetrahedral coordination of iron atoms with sulfur groups. Present in numerous proteins, these clusters are involved in key biological processes such as electron transfer, metabolic and regulatory processes, DNA synthesis and repair and protein structure stabilization. Fe-S clusters are synthesized mainly in the mitochondrion, where they are directly incorporated into mitochondrial Fe-S cluster-containing proteins or exported for cytoplasmic and nuclear cluster-protein assembly. In this study, we tested the hypothesis that inhibition of mitochondrial complex I by rotenone decreases Fe-S cluster synthesis and cluster content and activity of Fe-S cluster-containing enzymes. Inhibition of complex I resulted in decreased activity of three Fe-S cluster-containing enzymes: mitochondrial and cytosolic aconitases and xanthine oxidase. In addition, the Fe-S cluster content of glutamine phosphoribosyl pyrophosphate amidotransferase and mitochondrial aconitase was dramatically decreased. The reduction in cytosolic aconitase activity was associated with an increase in iron regulatory protein (IRP) mRNA binding activity and with an increase in the cytoplasmic labile iron pool. Since IRP activity post-transcriptionally regulates the expression of iron import proteins, Fe-S cluster inhibition may result in a false iron deficiency signal. Given that inhibition of complex I and iron accumulation are hallmarks of idiopathic Parkinson's disease, the findings reported here may have relevance for understanding the pathophysiology of this disease. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Inhibition of Rac1 Activity in the Hippocampus Impairs the Forgetting of Contextual Fear Memory.

    PubMed

    Jiang, Lizhu; Mao, Rongrong; Zhou, Qixin; Yang, Yuexiong; Cao, Jun; Ding, Yuqiang; Yang, Yuan; Zhang, Xia; Li, Lingjiang; Xu, Lin

    2016-03-01

    Fear is crucial for survival, whereas hypermnesia of fear can be detrimental. Inhibition of the Rac GTPase is recently reported to impair the forgetting of initially acquired memory in Drosophila. Here, we investigated whether inhibition of Rac1 activity in rat hippocampus could contribute to the hypermnesia of contextual fear. We found that spaced but not massed training of contextual fear conditioning caused inhibition of Rac1 activity in the hippocampus and heightened contextual fear. Furthermore, intrahippocampal injection of the Rac1 inhibitor NSC23766 heightened contextual fear in massed training, while Rac1 activator CN04-A weakened contextual fear in spaced training rats. Our study firstly demonstrates that contextual fear memory in rats is actively regulated by Rac1 activity in the hippocampus, which suggests that the forgetting impairment of traumatic events in posttraumatic stress disorder may be contributed to the pathological inhibition of Rac1 activity in the hippocampus.

  14. Balancing practicality and hydrologic realism: a parsimonious approach for simulating rapid groundwater recharge via unsaturated-zone preferential flow

    USGS Publications Warehouse

    Mirus, Benjamin B.; Nimmo, J.R.

    2013-01-01

    The impact of preferential flow on recharge and contaminant transport poses a considerable challenge to water-resources management. Typical hydrologic models require extensive site characterization, but can underestimate fluxes when preferential flow is significant. A recently developed source-responsive model incorporates film-flow theory with conservation of mass to estimate unsaturated-zone preferential fluxes with readily available data. The term source-responsive describes the sensitivity of preferential flow in response to water availability at the source of input. We present the first rigorous tests of a parsimonious formulation for simulating water table fluctuations using two case studies, both in arid regions with thick unsaturated zones of fractured volcanic rock. Diffuse flow theory cannot adequately capture the observed water table responses at both sites; the source-responsive model is a viable alternative. We treat the active area fraction of preferential flow paths as a scaled function of water inputs at the land surface then calibrate the macropore density to fit observed water table rises. Unlike previous applications, we allow the characteristic film-flow velocity to vary, reflecting the lag time between source and deep water table responses. Analysis of model performance and parameter sensitivity for the two case studies underscores the importance of identifying thresholds for initiation of film flow in unsaturated rocks, and suggests that this parsimonious approach is potentially of great practical value.

  15. Inhibition of organic anion transporter (OAT) activity by cigarette smoke condensate.

    PubMed

    Sayyed, Katia; Le Vee, Marc; Abdel-Razzak, Ziad; Fardel, Olivier

    2017-10-01

    Cigarette smoke condensate (CSC) has previously been shown to impair activity and expression of hepatic drug transporters. In the present study, we provided evidence that CSC also hinders activity of organic anion transporters (OATs), notably expressed at the kidney level. CSC thus cis-inhibited OAT substrate uptake in OAT1- and OAT3-transfected HEK293 cells, in a concentration-dependent manner (IC 50 =72.1μg/mL for OAT1 inhibition and IC 50 =27.3μg/mL for OAT3 inhibition). By contrast, OAT4 as well as the renal organic cation transporter (OCT) 2 were less sensitive to the inhibitory effect of CSC (IC 50 =351.5μg/mL and IC 50 =226.2μg/mL, for inhibition of OAT4 and OCT2, respectively). OAT3 activity was further demonstrated to be blocked by some single chemicals present in cigarette smoke such as the heterocyclic amines AαC (IC 50 =11.3μM) and PhIP (IC 50 =1.9μM), whereas other major cigarette smoke components used at 100μM, like nicotine, the nitrosamine NNK and the polycyclic aromatic hydrocarbons benzo(a)pyrene and phenanthrene, were without effect. AαC and PhIP however failed to trans-stimulate activity of OAT3, suggesting that they were not substrates for this transporter. Taken together, these data establish OAT1 and OAT3 transporters as targets of cigarette smoke chemicals, which may contribute to smoking-associated pharmacokinetics alterations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Hypouricaemic action of mangiferin results from metabolite norathyriol via inhibiting xanthine oxidase activity.

    PubMed

    Niu, Yanfen; Liu, Jia; Liu, Hai-Yang; Gao, Li-Hui; Feng, Guo-Hua; Liu, Xu; Li, Ling

    2016-09-01

    Context Mangiferin has been reported to possess a potential hypouricaemic effect. However, the pharmacokinetic studies in rats showed that its oral bioavailability was only 1.2%, suggesting that mangiferin metabolites might exert the action. Objective The hypouricaemic effect and the xanthine oxidase inhibition of mangiferin and norathyriol, a mangiferin metabolite, were investigated. Inhibition of norathyriol analogues (compounds 3-9) toward xanthine oxidase was also evaluated. Materials and methods For a dose-dependent study, mangiferin (1.5-6.0 mg/kg) and norathyriol (0.92-3.7 mg/kg) were administered intragastrically to mice twice daily for five times. For a time-course study, mice received mangiferin and norathyriol both at a single dose of 7.1 μmol/kg. In vitro, inhibition of test compounds (2.4-2.4 mM) against xanthine oxidase activity was evaluated by the spectrophotometrical method. The inhibition type was identified from Lineweaver-Burk plots. Results Norathyriol (0.92, 1.85 and 3.7 mg/kg) dose dependently decreased the serum urate levels by 27.0, 33.6 and 37.4%, respectively. The action was more potent than that of mangiferin at the low dose, but was equivalent at the higher doses. Additionally, the hypouricaemic action of them exhibited a time dependence. In vitro, norathyriol markedly inhibited the xanthine oxidase activities, with the IC50 value of 44.6 μM, but mangiferin did not. The kinetic studies showed that norathyriol was an uncompetitive inhibitor by Lineweaver-Burk plots. The structure-activity relationships exhibited that three hydroxyl groups in norathyriol at the C-1, C-3 and C-6 positions were essential for maintaining xanthine oxidase inhibition. Discussion and conclusion Norathyriol was responsible for the hypouricaemic effect of mangiferin via inhibiting xanthine oxidase activity.

  17. Bilirubin induces a calcium-dependent inhibition of multifunctional Ca2+/calmodulin-dependent kinase II activity in vitro.

    PubMed

    Churn, S B; DeLorenzo, R J; Shapiro, S M

    1995-12-01

    Excessive bilirubin levels in newborn infants result in long-term neurologic deficits that remain after bilirubin levels return to normal. Much of the observed neurologic deficits can be attributed to bilirubin-induced, delayed neuronal cell death. Inhibition of calcium/calmodulin-dependent kinase II (CaM kinase II) activity that precedes cell death is observed in conditions such as seizure activity, stroke, and glutamate excitotoxicity. Because neonatal bilirubin exposure results in neuronal loss in developing brain systems, we tested whether bilirubin exposure would induce an immediate inhibition of CaM activity, in vitro. P-81 filtration assay of basal and calcium-stimulated kinase activity was performed under standard kinase assay conditions. Bilirubin and/or albumin was added to the reaction vessels to determine the effect of these agents on kinase activity. Bilirubin exposure resulted in a concentration-dependent inhibition of CaM kinase II activity (IC50 = 16.78 microM). At concentrations above 50 microM, bilirubin exposure resulted in a 71 +/- 8% (mean +/- SD) inhibition of kinase activity (p < 0.001, t test, n = 10). Bilirubin exposure did not result in kinase inhibition if excessive bilirubin was removed by albumin binding before stimulation of kinase activity (106.9 +/- 9.6% control activity, n = 5). However, removal of bilirubin by binding with albumin after calcium addition did not restore kinase activity. (36.1 +/- 3.8% control activity, n = 5). Thus, once inhibition was observed, the activity could not be restored by addition of albumin. The data suggest that bilirubin exposure resulted in a calcium-dependent inhibition of CaM kinase II activity that, once induced, was not reversible by removing bilirubin by the addition of albumin. Because inhibition of CaM kinase II activity has been correlated with delayed neuronal cell death in many neuropathologic conditions, bilirubin-induced inhibition of this enzyme may be a cellular mechanism by which

  18. ACE inhibition and antioxidant activity of different part of Channa striata prepared by various cooking method

    NASA Astrophysics Data System (ADS)

    Chasanah, E.; Budiari, S.; Thenawijaya, M.; Palupi, N. S.

    2018-03-01

    Channa striata (snakehead) extract has been known possessing positive activity, one of which is the ability to inhibit Angiotensin Converting Enzyme (ACE) activity in vitro. Aims of this study were to determine the effect of cooking and parts of C. striata, i.e. meat/fillet, gonad, skin, gill against the ACE inhibition activity and antioxidant activity in vitro. Heat processing methods used were direct boiling and indirect boiling and steamed at 100 °C for 10 min. ACE inhibition activity was analyzed using hippuryl-L-histidyl-L-leucine (HHL) as substrate and antioxidant activity was analyzed using DPPH method. The result shows that the higher the concentration of the extract (5 %, 20 %, 35 % and 50 %), the higher the antioxidant activity. The highest antioxidant activity was shown by gonad followed by meat extract, skin, and gill. Cooking treatment affected antioxidant activity, being the detrimental treatment were steam and direct boiling. The egg/gonad of C. striata showed the highest capability to inhibit ACE activity followed by meat/fillet, gill and skin. In concentration of 10 mg, extract of C. striata gonad was comparable to captopril, a commercial hypertension drug. While uncooked fillet showed the highest ACE inhibition activity followed by indirect boiling, direct boiling and steaming.

  19. AMPK activators inhibit the proliferation of human melanomas bearing the activated MAPK pathway.

    PubMed

    Petti, Carlotta; Vegetti, Claudia; Molla, Alessandra; Bersani, Ilaria; Cleris, Loredana; Mustard, Kirsty J; Formelli, Franca; Hardie, Grahame D; Sensi, Marialuisa; Anichini, Andrea

    2012-10-01

    Raf/MEK/ERK signaling can inhibit the liver kinase B1-AMP-activated protein kinase (LKB1-AMPK) pathway, thus rendering melanoma cells resistant to energy stress conditions. We evaluated whether pharmacological reactivation of the AMPK function could exert antitumor effects on melanoma cells bearing this pathway constitutively active because of a mutation in NRAS or BRAF genes. Nine melanoma cell lines were treated with the AMPK activators 5-aminoimidazole-4-carboxamide-ribonucleoside (AICAR) and phenformin. The activation of AMPK enzymatic activity, phosphorylation of AMPK and acetyl-CoA carboxylase kinase, in-vitro proliferation, cell cycle, and in-vivo growth of xenografts in nude mice were evaluated. AICAR and phenformin promoted phosphorylation and enzymatic activity of AMPK, as well as phosphorylation of the AMPK downstream target acetyl-CoA carboxylase. Drug treatment of either BRAF-mutant or NRAS-mutant melanomas, at doses not inducing cell death, was accompanied by a dose-dependent decrease in melanoma cell proliferation because of cell cycle arrest in either the G0/G1 or the S phase, associated with an increased expression of the p21 cell cycle inhibitor. Melanomas isolated from subcutaneously implanted mice, 25 days from treatment with AICAR, showed increased staining of the senescence-associated marker β-galactosidase, high p21 expression, and evidence of necrosis. Altogether, these results indicate that pharmacological activators of AMPK-dependent pathways inhibit the cell growth of melanoma cells with active Raf/MEK/ERK signaling and provide a rationale for further investigation on their use in combination therapies.

  20. Preferential ascus discharge during cross maturation in Sordaria brevicollis.

    PubMed

    MacDonald, D J; Bond, D J

    1974-02-01

    Crosses involving spore color mutants of Sordaria brevicollis all showed a decline in the frequency of second division asymmetric asci (2:2:2:2's) as the cross matured. This decline was due to the preferential maturation and/or discharge of these asci. The proportion of spindle overlap and recombinational asci within the group did not change as shown by ascus dissection. The preferential discharge was also found to occur in two-point crosses where the asci did not contain wild-type spores.

  1. The tarantula toxins ProTx-II and huwentoxin-IV differentially interact with human Nav1.7 voltage sensors to inhibit channel activation and inactivation.

    PubMed

    Xiao, Yucheng; Blumenthal, Kenneth; Jackson, James O; Liang, Songping; Cummins, Theodore R

    2010-12-01

    The voltage-gated sodium channel Na(v)1.7 plays a crucial role in pain, and drugs that inhibit hNa(v)1.7 may have tremendous therapeutic potential. ProTx-II and huwentoxin-IV (HWTX-IV), cystine knot peptides from tarantula venoms, preferentially block hNa(v)1.7. Understanding the interactions of these toxins with sodium channels could aid the development of novel pain therapeutics. Whereas both ProTx-II and HWTX-IV have been proposed to preferentially block hNa(v)1.7 activation by trapping the domain II voltage-sensor in the resting configuration, we show that specific residues in the voltage-sensor paddle of domain II play substantially different roles in determining the affinities of these toxins to hNa(v)1.7. The mutation E818C increases ProTx-II's and HWTX-IV's IC(50) for block of hNa(v)1.7 currents by 4- and 400-fold, respectively. In contrast, the mutation F813G decreases ProTx-II affinity by 9-fold but has no effect on HWTX-IV affinity. It is noteworthy that we also show that ProTx-II, but not HWTX-IV, preferentially interacts with hNa(v)1.7 to impede fast inactivation by trapping the domain IV voltage-sensor in the resting configuration. Mutations E1589Q and T1590K in domain IV each decreased ProTx-II's IC(50) for impairment of fast inactivation by ~6-fold. In contrast mutations D1586A and F1592A in domain-IV increased ProTx-II's IC(50) for impairment of fast inactivation by ~4-fold. Our results show that whereas ProTx-II and HWTX-IV binding determinants on domain-II may overlap, domain II plays a much more crucial role for HWTX-IV, and contrary to what has been proposed to be a guiding principle of sodium channel pharmacology, molecules do not have to exclusively target the domain IV voltage-sensor to influence sodium channel inactivation.

  2. Inhibition of PAI-1 Antiproteolytic Activity Against tPA by RNA Aptamers

    PubMed Central

    Damare, Jared; Brandal, Stephanie

    2014-01-01

    Plasminogen activator inhibitor-1 (PAI-1; SERPINE1) inhibits the plasminogen activators: tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA). Elevated levels of PAI-1 have been correlated with an increased risk for cardiovascular disease. Pharmacologically suppressing PAI-1 might prevent, or successfully treat PAI-1 related vascular diseases. This can potentially be accomplished by using small RNA molecules (aptamers). This study's goal is to develop RNA aptamers to a region of PAI-1 that will prevent the ability of PAI-1 to interact with the plasminogen activators. The aptamers were generated through a systematic evolution of ligands via exponential enrichment approach that ensures the creation of RNA molecules that bind to our target protein, PAI-1. In vitro assays were used to determine the effect of these aptamers on PAI-1's inhibitory activity. Three aptamers that bind to PAI-1 with affinities in the nanomolar range were isolated. The aptamer clones R10-4 and R10-2 inhibited PAI-1's antiproteolytic activity against tPA and disrupted PAI-1's ability to form a stable covalent complex with tPA. Increasing aptamer concentrations correlated positively with an increase in cleaved PAI-1. To the best of our knowledge, this is the first report of RNA molecules that inhibit the antiproteolytic activity of PAI-1. PMID:24922319

  3. COUP-TFII inhibits NFkappaB activation in endocrine-resistant breast cancer cells

    PubMed Central

    Litchfield, Lacey M.; Appana, Savitri N.; Datta, Susmita; Klinge, Carolyn M.

    2016-01-01

    Reduced COUP-TFII expression contributes to endocrine resistance in breast cancer cells. Endocrine-resistant breast cancer cells have higher NFkappa B (NFκB) activity and target gene expression. The goal of this study was to determine if COUP-TFII modulates NFκB activity. Endocrine-resistant LCC9 cells with low endogenous COUP-TFII displayed ~5-fold higher basal NFκB activity than parental endocrine-sensitive MCF-7 breast cancer cells. Transient transfection of LCC9 cells with COUP-TFII inhibited NFκB activation and reduced NFκB target gene expression. COUP-TFII and NFκB were inversely correlated in breast cancer patient samples. Endogenous COUP-TFII coimmunoprecipitated with NFκB subunits RelB and NFκB1 in MCF-7 cells. COUP-TFII inhibited NFκB-DNA binding in vitro and impaired coactivator induced NFκB transactivation. LCC9 cells were growth-inhibited by an NFκB inhibitor and 4-hydroxytamoxifen compared to MCF-7 cells. Together these data indicate a novel role for COUP-TFII in suppression of NFκB activity and explain, in part, why decreased COUP-TFII expression results in an endocrine-resistant phenotype. PMID:24141032

  4. An inhibitory interaction of human cortical responses to stimuli preferentially exciting Aδ or C fibers

    PubMed Central

    Tran, Tuan D.; Matre, Dagfinn; Casey, Kenneth L.

    2008-01-01

    Finely myelinated (type Aδ) and unmyelinated (type C) fibers are the major afferent inputs to spinothalamic tract neurons mediating sensory and reflex responses to noxious and thermal stimuli. These two fiber types differ in their sensory and biophysical properties, raising questions about the interaction of their supraspinal responses. Therefore, we investigated the interaction of cortical responses to stimuli that preferentially excite these fibers in human subjects using evoked potential recordings in a paired conditioning stimulation (CS) and test stimulation (TS) paradigm. There were two experiments, one with Aδ as CS and C as TS (Aδ-C) and another with these stimuli reversed (C-Aδ). We used intra-epidermal electrical pulses applied to the dorsal left hand at 2 and 1 × pinprick threshold (pp) for the preferential stimulation of Aδ fibers and 37 – 50°C contact heat pulses applied to the left or right thenar and left hypothenar eminences for the preferential stimulation of C fibers. We found that the cortical response to preferential Aδ or C fiber stimulation was attenuated whenever either cortical response preceded the other. Standardized values of peak and integrated amplitudes were < 1 in all paring conditions and in all subjects in both experiments. The suppressive effect varied in magnitude with the intensity of the conditioning stimulus in both Aδ-C and C-Aδ experiments. Furthermore, intra-segmental interaction was differentially effective for Aδ conditioning, (peak amplitude, p < 0.008; ANOVA). Our experiments provide the first neurophysiological evidence for a somatotopically distributed, mutually suppressive interaction between cortical responses to preferentially activated Aδ and C afferents in humans. This suppressive interaction of cortical responses suggests contrasting and possibly mutually exclusive sensori-motor functions mediated through the Aδ and C fiber afferent channels. PMID:18308475

  5. Inhibition of Anaerobic Phosphate Release by Nitric Oxide in Activated Sludge

    PubMed Central

    Van Niel, E. W. J.; Appeldoorn, K. J.; Zehnder, A. J. B.; Kortstee, G. J. J.

    1998-01-01

    Activated sludge not containing significant numbers of denitrifying, polyphosphate [poly(P)]-accumulating bacteria was grown in a fill-and-draw system and exposed to alternating anaerobic and aerobic periods. During the aerobic period, poly(P) accumulated up to 100 mg of P · g of (dry) weight. When portions of the sludge were incubated anaerobically in the presence of acetate, 80 to 90% of the intracellular poly(P) was degraded and released as orthophosphate. Degradation of poly(P) was mainly catalyzed by the concerted action of polyphosphate:AMP phosphotransferase and adenylate kinase, resulting in ATP formation. In the presence of 0.3 mM nitric oxide (NO) in the liquid-phase release of phosphate, uptake of acetate, formation of poly-β-hydroxybutyrate, utilization of glycogen, and formation of ATP were severely inhibited or completely abolished. In cell extracts of the sludge, adenylate kinase activity was completely inhibited by 0.15 mM NO. The nature of this inhibition was probably noncompetitive, similar to that with hog adenylate kinase. Activated sludge polyphosphate glucokinase was also completely inhibited by 0.15 mM NO. It is concluded that the inhibitory effect of NO on acetate-mediated phosphate release by the sludge used in this study is due to the inhibition of adenylate kinase in the phosphate-releasing organisms. The inhibitory effect of nitrate and nitrite on phosphate release is probably due to their conversion to NO. The lack of any inhibitory effect of NO on adenylate kinase of the poly(P)-accumulating Acinetobacter johnsonii 210A suggests that this type of organism is not involved in the enhanced biological phosphate removal by the sludges used. PMID:9687452

  6. The preferential flow of soil: A widespread phenomenon in pedological perspectives

    NASA Astrophysics Data System (ADS)

    Zhang, Yinghu; Zhang, Mingxiang; Niu, Jianzhi; Zheng, Haijin

    2016-06-01

    The article provides an overview of studies about the preferential flow phenomenon. This phenomenon is one of the types of the transportation of water solution through the soil profile by preferential channels (pathways) with a relatively high speed and with a slight change in the chemical composition of the solution. Interest in this phenomenon has risen sharply in the last two decades due to the observed fast transportation of contaminants from soil surface into groundwater level. On the basis of the literature data, the authors give the definition of this phenomenon, consider its types, degree, features, mechanisms, methods and models and research perspectives, in particular the interaction between preferential flow and soil matrix flow. The article considers the aspects of the movement of soil water carrying heavy metals and pesticides; hence, it concerns the protection of environment and people's health. It provides the thorough review of the studies on the preferential flow, and describes the research directions and their development.

  7. Pulsatile equibiaxial stretch inhibits thrombin-induced RhoA and NF-{kappa}B activation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Haga, Jason H.; Kaunas, Roland; Radeff-Huang, Julie

    2008-07-18

    This study investigated interactions between the effects of mechanical stretch and thrombin on RhoA activation in rat aortic smooth muscle cells (RASMC). Equibiaxial, pulsatile stretch, or thrombin produced a significant increase in RhoA activation. Surprisingly, in combination, 30 min of stretch inhibited the ability of thrombin to activate RhoA. NO donors and 8-bromo-cGMP significantly inhibited thrombin-induced RhoA activation. Interestingly, the nitric oxide synthase (NOS) inhibitor L-NAME increased basal RhoA activity, suggesting that NOS activity exerts a tonic inhibition on RhoA. Stretching RASMC increases nitrite production, consistent with the idea that NO contributes to the inhibitory effects of stretch. Thrombin stimulatesmore » MAP kinase and NF-{kappa}B pathways through Rho and these responses were blocked by 8-bromo-cGMP or stretch and restored by L-NAME. These data suggest that stretch, acting through NO and cGMP, can prevent the ability of thrombin to stimulate Rho signaling pathways that contribute to pathophysiological proliferative and inflammatory responses.« less

  8. Disposition, Metabolism and Histone Deacetylase and Acetyltransferase Inhibition Activity of Tetrahydrocurcumin and Other Curcuminoids

    PubMed Central

    Novaes, Júlia T.; Sayre, Casey L.; Majeed, Muhammed; Ho, Emmanuel A.; Oliveira, Ana Luísa de P.; Martinez, Stephanie E.; Davies, Neal M.; Lakowski, Ted M.

    2017-01-01

    Tetrahydrocurcumin (THC), curcumin and calebin-A are curcuminoids found in turmeric (Curcuma longa). Curcuminoids have been established to have a variety of pharmacological activities and are used as natural health supplements. The purpose of this study was to identify the metabolism, excretion, antioxidant, anti-inflammatory and anticancer properties of these curcuminoids and to determine disposition of THC in rats after oral administration. We developed a UHPLC–MS/MS assay for THC in rat serum and urine. THC shows multiple redistribution phases with corresponding increases in urinary excretion rate. In-vitro antioxidant activity, histone deacetylase (HDAC) activity, histone acetyltransferase (HAT) activity and anti-inflammatory inhibitory activity were examined using commercial assay kits. Anticancer activity was determined in Sup-T1 lymphoma cells. Our results indicate THC was poorly absorbed after oral administration and primarily excreted via non-renal routes. All curcuminoids exhibited multiple pharmacological effects in vitro, including potent antioxidant activity as well as inhibition of CYP2C9, CYP3A4 and lipoxygenase activity without affecting the release of TNF-α. Unlike curcumin and calebin-A, THC did not inhibit HDAC1 and PCAF and displayed a weaker growth inhibition activity against Sup-T1 cells. We show evidence for the first time that curcumin and calebin-A inhibit HAT and PCAF, possibly through a Michael-addition mechanism. PMID:29023392

  9. Inhibition of the hammerhead ribozyme by neomycin.

    PubMed Central

    Stage, T K; Hertel, K J; Uhlenbeck, O C

    1995-01-01

    A series of antibiotics was tested for stimulation or inhibition of the hammerhead ribozyme cleavage reaction. Neomycin was found to be a potent inhibitor of the reaction with a Kl of 13.5 microM. Two hammerheads with well-characterized kinetics were used to determine which steps in the reaction mechanism were inhibited by neomycin. The data suggest that neomycin interacts preferentially with the enzyme-substrate complex and that this interaction leads to a reduction in the cleavage rate by stabilizing the ground state of the complex and destabilizing the transition state of the cleavage step. A comparison of neomycin with other aminoglycosides and inhibitors of hammerhead cleavage implies that the ammonium ions of neomycin are important for the antibiotic-hammerhead interaction. PMID:7489494

  10. Mirror-touch synaesthesia: Difficulties inhibiting the other.

    PubMed

    Santiesteban, Idalmis; Bird, Geoffrey; Tew, Oliver; Cioffi, Maria Cristina; Banissy, Michael J

    2015-10-01

    Individuals with mirror touch synaesthesia (MTS) experience touch on their own body when observing others being touched. A recent account proposes that such rare experiences could be linked to impairment in self-other representations. Here we tested participants with MTS on a battery of social cognition tests and found that compared to non-synaesthete controls, the MTS group showed impairment in imitation-inhibition but not in visual perspective taking or theory of mind. Although all of these socio-cognitive abilities rely on the control of self-other representations, they differ as to whether the self, or the other, should be preferentially represented. For imitation-inhibition, representations of the other should be inhibited and self-representations should be enhanced, whereas the opposite is true for visual perspective taking and theory of mind. These findings suggest that MTS is associated with a specific deficit in inhibiting representation of other individuals and shed light on the fractionability of processes underlying typical social cognition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Cyclosporin derivatives inhibit hepatitis B virus entry without interfering with NTCP transporter activity.

    PubMed

    Shimura, Satomi; Watashi, Koichi; Fukano, Kento; Peel, Michael; Sluder, Ann; Kawai, Fumihiro; Iwamoto, Masashi; Tsukuda, Senko; Takeuchi, Junko S; Miyake, Takeshi; Sugiyama, Masaya; Ogasawara, Yuki; Park, Sam-Yong; Tanaka, Yasuhito; Kusuhara, Hiroyuki; Mizokami, Masashi; Sureau, Camille; Wakita, Takaji

    2017-04-01

    The sodium taurocholate co-transporting polypeptide (NTCP) is the main target of most hepatitis B virus (HBV) specific entry inhibitors. Unfortunately, these agents also block NTCP transport of bile acids into hepatocytes, and thus have the potential to cause adverse effects. We aimed to identify small molecules that inhibit HBV entry while maintaining NTCP transporter function. We characterized a series of cyclosporine (CsA) derivatives for their anti-HBV activity and NTCP binding specificity using HepG2 cells overexpressing NTCP and primary human hepatocytes. The four most potent derivatives were tested for their capacity to prevent HBV entry, but maintain NTCP transporter function. Their antiviral activity against different HBV genotypes was analysed. We identified several CsA derivatives that inhibited HBV infection with a sub-micromolar IC 50 . Among them, SCY446 and SCY450 showed low activity against calcineurin (CN) and cyclophilins (CyPs), two major CsA cellular targets. This suggested that instead, these compounds interacted directly with NTCP to inhibit viral attachment to host cells, and have no immunosuppressive function. Importantly, we found that SCY450 and SCY995 did not impair the NTCP-dependent uptake of bile acids, and inhibited multiple HBV genotypes including a clinically relevant nucleoside analog-resistant HBV isolate. This is the first example of small molecule selective inhibition of HBV entry with no decrease in NTCP transporter activity. It suggests that the anti-HBV activity can be functionally separated from bile acid transport. These broadly active anti-HBV molecules are potential candidates for developing new drugs with fewer adverse effects. In this study, we identified new compounds that selectively inhibited hepatitis B virus (HBV) entry, and did not impair bile acid uptake. Our evidence offers a new strategy for developing anti-HBV drugs with fewer side effects. Copyright © 2016 European Association for the Study of the Liver

  12. Obesity and lipid stress inhibit carnitine acetyltransferase activity[S

    PubMed Central

    Seiler, Sarah E.; Martin, Ola J.; Noland, Robert C.; Slentz, Dorothy H.; DeBalsi, Karen L.; Ilkayeva, Olga R.; An, Jie; Newgard, Christopher B.; Koves, Timothy R.; Muoio, Deborah M.

    2014-01-01

    Carnitine acetyltransferase (CrAT) is a mitochondrial matrix enzyme that catalyzes the interconversion of acetyl-CoA and acetylcarnitine. Emerging evidence suggests that this enzyme functions as a positive regulator of total body glucose tolerance and muscle activity of pyruvate dehydrogenase (PDH), a mitochondrial enzyme complex that promotes glucose oxidation and is feedback inhibited by acetyl-CoA. Here, we used tandem mass spectrometry-based metabolic profiling to identify a negative relationship between CrAT activity and muscle content of lipid intermediates. CrAT specific activity was diminished in muscles from obese and diabetic rodents despite increased protein abundance. This reduction in enzyme activity was accompanied by muscle accumulation of long-chain acylcarnitines (LCACs) and acyl-CoAs and a decline in the acetylcarnitine/acetyl-CoA ratio. In vitro assays demonstrated that palmitoyl-CoA acts as a direct mixed-model inhibitor of CrAT. Similarly, in primary human myocytes grown in culture, nutritional and genetic manipulations that promoted mitochondrial influx of fatty acids resulted in accumulation of LCACs but a pronounced decrease of CrAT-derived short-chain acylcarnitines. These results suggest that lipid-induced antagonism of CrAT might contribute to decreased PDH activity and glucose disposal in the context of obesity and diabetes. PMID:24395925

  13. Activation of peroxisome proliferator-activated receptor δ inhibits angiotensin II-induced activation of matrix metalloproteinase-2 in vascular smooth muscle cells.

    PubMed

    Ham, Sun Ah; Lee, Hanna; Hwang, Jung Seok; Kang, Eun Sil; Yoo, Taesik; Paek, Kyung Shin; Do, Jeong Tae; Park, Chankyu; Oh, Jae-Wook; Kim, Jin-Hoi; Han, Chang Woo; Seo, Han Geuk

    2014-01-01

    We investigated the role of peroxisome proliferator-activated receptor (PPAR) δ on angiotensin (Ang) II-induced activation of matrix metalloproteinase (MMP)-2 in vascular smooth muscle cells (VSMCs). Activation of PPARδ by GW501516, a specific ligand for PPARδ, attenuated Ang II-induced activation of MMP-2 in a concentration-dependent manner. GW501516 also inhibited the generation of reactive oxygen species in VSMCs treated with Ang II. A marked increase in the mRNA levels of tissue inhibitor of metalloproteinase (TIMP)-2 and -3, endogenous antagonists of MMPs, was also observed in GW501516-treated VSMCs. These effects were markedly reduced in the presence of siRNAs against PPARδ, indicating that the effects of GW501516 are PPARδ dependent. Among the protein kinases inhibited by GW501516, suppression of phosphatidylinositol 3-kinase/Akt signaling was shown to have the greatest effect on activation of MMP-2 in VSMCs treated with Ang II. Concomitantly, GW501516-mediated inhibition of MMP-2 activation in VSMCs treated with Ang II was associated with the suppression of cell migration to levels approaching those in cells not exposed to Ang II. Thus, activation of PPARδ confers resistance to Ang II-induced degradation of the extracellular matrix by upregulating expression of its endogenous inhibitor TIMP and thereby modulating cellular responses to Ang II in vascular cells. © 2014 S. Karger AG, Basel.

  14. The dual action of poly(ADP-ribose) polymerase -1 (PARP-1) inhibition in HIV-1 infection: HIV-1 LTR inhibition and diminution in Rho GTPase activity

    PubMed Central

    Rom, Slava; Reichenbach, Nancy L.; Dykstra, Holly; Persidsky, Yuri

    2015-01-01

    Multifactorial mechanisms comprising countless cellular factors and virus-encoded transactivators regulate the transcription of HIV-1 (HIV). Since poly(ADP-ribose) polymerase 1 (PARP-1) regulates numerous genes through its interaction with various transcription factors, inhibition of PARP-1 has surfaced recently as a powerful anti-inflammatory tool. We suggest a novel tactic to diminish HIV replication via PARP-1 inhibition in an in vitro model system, exploiting human primary monocyte-derived macrophages (MDM). PARP-1 inhibition was capable to lessen HIV replication in MDM by 60–80% after 7 days infection. Tat, tumor necrosis factor α (TNFα), and phorbol 12-myristate 13-acetate (PMA) are known triggers of the Long Terminal Repeat (LTR), which can switch virus replication. Tat overexpression in MDM transfected with an LTR reporter plasmid resulted in a 4.2-fold increase in LTR activation; PARP inhibition caused 70% reduction of LTR activity. LTR activity, which increased 3-fold after PMA or TNFα treatment, was reduced by PARP inhibition (by 85–95%). PARP inhibition in MDM exhibited 90% diminution in NFκB activity (known to mediate TNFα- and PMA-induced HIV LTR activation). Cytoskeleton rearrangements are important in effective HIV-1 infection. PARP inactivation reduced actin cytoskeleton rearrangements by affecting Rho GTPase machinery. These discoveries suggest that inactivation of PARP suppresses HIV replication in MDM by via attenuation of LTR activation, NFκB suppression and its effects on the cytoskeleton. PARP appears to be essential for HIV replication and its inhibition may provide an effective approach to management of HIV infection. PMID:26379653

  15. The dual action of poly(ADP-ribose) polymerase -1 (PARP-1) inhibition in HIV-1 infection: HIV-1 LTR inhibition and diminution in Rho GTPase activity.

    PubMed

    Rom, Slava; Reichenbach, Nancy L; Dykstra, Holly; Persidsky, Yuri

    2015-01-01

    Multifactorial mechanisms comprising countless cellular factors and virus-encoded transactivators regulate the transcription of HIV-1 (HIV). Since poly(ADP-ribose) polymerase 1 (PARP-1) regulates numerous genes through its interaction with various transcription factors, inhibition of PARP-1 has surfaced recently as a powerful anti-inflammatory tool. We suggest a novel tactic to diminish HIV replication via PARP-1 inhibition in an in vitro model system, exploiting human primary monocyte-derived macrophages (MDM). PARP-1 inhibition was capable to lessen HIV replication in MDM by 60-80% after 7 days infection. Tat, tumor necrosis factor α (TNFα), and phorbol 12-myristate 13-acetate (PMA) are known triggers of the Long Terminal Repeat (LTR), which can switch virus replication. Tat overexpression in MDM transfected with an LTR reporter plasmid resulted in a 4.2-fold increase in LTR activation; PARP inhibition caused 70% reduction of LTR activity. LTR activity, which increased 3-fold after PMA or TNFα treatment, was reduced by PARP inhibition (by 85-95%). PARP inhibition in MDM exhibited 90% diminution in NFκB activity (known to mediate TNFα- and PMA-induced HIV LTR activation). Cytoskeleton rearrangements are important in effective HIV-1 infection. PARP inactivation reduced actin cytoskeleton rearrangements by affecting Rho GTPase machinery. These discoveries suggest that inactivation of PARP suppresses HIV replication in MDM by via attenuation of LTR activation, NFκB suppression and its effects on the cytoskeleton. PARP appears to be essential for HIV replication and its inhibition may provide an effective approach to management of HIV infection.

  16. Divergent effects of postmortem ambient temperature on organophosphorus- and carbamate-inhibited brain cholinesterase activity in birds

    USGS Publications Warehouse

    Hill, E.F.

    1989-01-01

    Time- and temperature-dependent postmortem changes in inhibited brain cholinesterase (ChE) activity may confound diagnosis of field poisoning of wildlife by anticholinesterase pesticide. Carbamate-inhibited ChE activity may return to normal within 1 to 2 days of exposure of intact carcass to moderate ambient temperature (18-32C). Organophosphorus-inhibited ChE activity becomes more depressed over the same time. Uninhibited ChE activity was resilient to above freezing temperature to 32C for 1 day and 25C for 3 days. Carbamate- and organophosphorus-inhibited ChE can be separated by incubation of homogenate for 1 hour at physiological temperatures; carbamylated ChE can be readily reactivated while phosphorylated ChE cannot.

  17. Poxvirus-encoded TNF decoy receptors inhibit the biological activity of transmembrane TNF.

    PubMed

    Pontejo, Sergio M; Alejo, Ali; Alcami, Antonio

    2015-10-01

    Poxviruses encode up to four different soluble TNF receptors, named cytokine response modifier B (CrmB), CrmC, CrmD and CrmE. These proteins mimic the extracellular domain of the cellular TNF receptors to bind and inhibit the activity of TNF and, in some cases, other TNF superfamily ligands. Most of these ligands are released after the enzymic cleavage of a membrane precursor. However, transmembrane TNF (tmTNF) is not only a precursor of soluble TNF but also exerts specific pro-inflammatory and immunological activities. Here, we report that viral TNF receptors bound and inhibited tmTNF and describe some interesting differences in their activity against the soluble cytokine. Thus, CrmE, which does not inhibit mouse soluble TNF, could block murine tmTNF-induced cytotoxicity. We propose that this anti-tmTNF effect should be taken into consideration when assessing the role of viral TNF decoy receptors in the pathogenesis of poxvirus.

  18. Rho-associated kinase (ROCK) inhibition reverses low cell activity on hydrophobic surfaces.

    PubMed

    Tian, Yu Shun; Kim, Hyun Jung; Kim, Hyun-Man

    2009-08-28

    Hydrophobic polymers do not offer an adequate scaffold surface for cells to attach, migrate, proliferate, and differentiate. Thus, hydrophobic scaffolds for tissue engineering have traditionally been physicochemically modified to enhance cellular activity. However, modifying the surface by chemical or physical treatment requires supplementary engineering procedures. In the present study, regulation of a cell signal transduction pathway reversed the low cellular activity on a hydrophobic surface without surface modification. Inhibition of Rho-associated kinase (ROCK) by Y-27632 markedly enhanced adhesion, migration, and proliferation of osteoblastic cells cultured on a hydrophobic polystyrene surface. ROCK inhibition regulated cell-cycle-related molecules on the hydrophobic surface. This inhibition also decreased expression of the inhibitors of cyclin-dependent kinases such as p21(cip1) and p27(kip1) and increased expression of cyclin A and D. These results indicate that defective cellular activity on the hydrophobic surface can be reversed by the control of a cell signal transduction pathway without physicochemical surface modification.

  19. Piperine Inhibits the Activities of Platelet Cytosolic Phospholipase A2 and Thromboxane A2 Synthase without Affecting Cyclooxygenase-1 Activity: Different Mechanisms of Action Are Involved in the Inhibition of Platelet Aggregation and Macrophage Inflammatory Response

    PubMed Central

    Son, Dong Ju; Akiba, Satoshi; Hong, Jin Tae; Yun, Yeo Pyo; Hwang, Seock Yeon; Park, Young Hyun; Lee, Sung Eun

    2014-01-01

    PURPOSE: Piperine, a major alkaloid of black pepper (Piper nigrum) and long pepper (Piper longum), was shown to have anti-inflammatory activity through the suppression of cyclooxygenase (COX)-2 gene expression and enzyme activity. It is also reported to exhibit anti-platelet activity, but the mechanism underlying this action remains unknown. In this study, we investigated a putative anti-platelet aggregation mechanism involving arachidonic acid (AA) metabolism and how this compares with the mechanism by which it inhibits macrophage inflammatory responses; METHODS: Rabbit platelets and murine macrophage RAW264.7 cells were treated with piperine, and the effect of piperine on the activity of AA-metabolizing enzymes, including cytosolic phospholipase A2 (cPLA2), COX-1, COX-2, and thromboxane A2 (TXA2) synthase, as well as its effect on AA liberation from the plasma membrane components, were assessed using isotopic labeling methods and enzyme immunoassay kit; RESULTS: Piperine significantly suppressed AA liberation by attenuating cPLA2 activity in collagen-stimulated platelets. It also significantly inhibited the activity of TXA2 synthase, but not of COX-1, in platelets. These results suggest that piperine inhibits platelet aggregation by attenuating cPLA2 and TXA2 synthase activities, rather than through the inhibition of COX-1 activity. On the other hand, piperine significantly inhibited lipopolysaccharide-induced generation of prostaglandin (PG)E2 and PGD2 in RAW264.7 cells by suppressing the activity of COX-2, without effect on cPLA2; CONCLUSION: Our findings indicate that piperine inhibits platelet aggregation and macrophage inflammatory response by different mechanisms. PMID:25153972

  20. Blockade of CD26 signaling inhibits human osteoclast development.

    PubMed

    Nishida, Hiroko; Suzuki, Hiroshi; Madokoro, Hiroko; Hayashi, Mutsumi; Morimoto, Chikao; Sakamoto, Michiie; Yamada, Taketo

    2014-11-01

    Bone remodeling is maintained by the delicate balance between osteoblasts (OBs) and osteoclasts (OCs). However, the role of CD26 in regulating bone remodeling has not yet been characterized. We herein show that CD26 is preferentially expressed on normal human OCs and is intensely expressed on activated human OCs in osteolytic bone alterations. Macrophage-colony stimulating factor (M-CSF) and soluble receptor activator of NF-κB ligand (sRANKL) induced human OC differentiation, in association with CD26 expression on monocyte-macrophage lineage cells. CD26 expression was accompanied by increased phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), which is crucial for early human OC differentiation. The humanized anti-CD26 monoclonal antibody, huCD26mAb, impaired the formation and function of tartrate-resistant acid phosphatase (TRAP)/CD26 positive multi-nucleated (nuclei > 3) OCs with maturation in the manner of dose-dependency. It was revealed that huCD26mAb inhibits early OC differentiation via the inactivation of MKK3/6, p38 MAPK and subsequent dephosphorylation of microphthalmia-associated transcription factor (mi/Mitf). These inhibitions occur immediately after RANKL binds to RANK on the human OC precursor cells and were demonstrated using the OC functional assays. huCD26mAb subsequently impaired OC maturation and bone resorption by suppressing the expression of TRAP and OC fusion proteins. In addition, p38 MAPK inhibitor also strongly inhibited OC formation and function. Our results suggest that the blockade of CD26 signaling impairs the development of human functional OCs by inhibiting p38 MAPK-mi/Mitf phosphorylation pathway and that targeting human OCs with huCD26mAb may have therapeutic potential for the treatment of osteolytic lesions following metastasis to alleviate bone destruction and reduce total skeletal-related events (SREs). © 2014 American Society for Bone and Mineral Research.

  1. Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol

    PubMed Central

    Uchida, Ryuji; Ishikawa, Seiko; Tomoda, Hiroshi

    2014-01-01

    2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L) in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated melanin formation in intact B16 melanoma cells. PMID:26579376

  2. Inhibition of tyrosinase activity and melanine pigmentation by 2-hydroxytyrosol.

    PubMed

    Uchida, Ryuji; Ishikawa, Seiko; Tomoda, Hiroshi

    2014-04-01

    2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L) in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated melanin formation in intact B16 melanoma cells.

  3. Antioxidant, antityrosinase, anticholinesterase, and nitric oxide inhibition activities of three malaysian macaranga species.

    PubMed

    Mazlan, Nor Aishah; Mediani, Ahmed; Abas, Faridah; Ahmad, Syahida; Shaari, Khozirah; Khamis, Shamsul; Lajis, N H

    2013-01-01

    The methanol extracts of three Macaranga species (M. denticulata, M. pruinosa, and M. gigantea) were screened to evaluate their total phenolic contents and activities as cholinesterase inhibitors, nitric oxide (NO) production inhibitors, tyrosinase inhibitors, and antioxidants. The bark of M. denticulata showed the highest total phenolic content (2682 mg gallic acid equivalent (GAE)/100 g) and free radical scavenging activity (IC50 = 0.063 mg/mL). All of the samples inhibited linoleic acid peroxidation by greater than 80%, with the leaves of M. gigantea exhibiting the highest inhibition of 92.21%. Most of the samples exhibited significant antioxidant potential. The bark of M. denticulata and the leaves of both M. pruinosa and M. gigantea exhibited greater than 50% tyrosinase inhibition, with the bark of M. denticulata having the highest percentage of inhibition (68.7%). The bark and leaves of M. denticulata exhibited greater than 50% inhibition (73.82% and 54.50%, resp.) of the acetylcholinesterase enzyme (AChE), while none of the samples showed any significant inhibition of butyrylcholinesterase (BChE). Only the bark of M. denticulata and M. gigantea displayed greater than 50% inhibition of nitric oxide production in cells (81.79% and 56.51%, resp.). These bioactivities indicate that some Macaranga spp. have therapeutic potential in medicinal research.

  4. Preferential Ascus Discharge during Cross Maturation in SORDARIA BREVICOLLIS

    PubMed Central

    MacDonald, D. J.; Bond, D. J.

    1974-01-01

    Crosses involving spore color mutants of Sordaria brevicollis all showed a decline in the frequency of second division asymmetric asci (2:2:2:2's) as the cross matured. This decline was due to the preferential maturation and/or discharge of these asci. The proportion of spindle overlap and recombinational asci within the group did not change as shown by ascus dissection. The preferential discharge was also found to occur in two-point crosses where the asci did not contain wild-type spores. PMID:4822469

  5. Increasing Stability and Activity of Core-Shell Catalysts by Preferential Segregation of Oxide on Edges and Vertexes: Oxygen Reduction on Ti-Au@Pt/C

    DOE PAGES

    Hu, J.; Wu, L.; Kuttiyiel, K.; ...

    2016-06-30

    We describe a new class of core-shell nanoparticle catalysts having edges and vertexes covered by refractory metal oxide that preferentially segregates onto these catalyst sites. The monolayer shell is deposited on the oxidefree core atoms. The oxide on edges and vertexes induces high catalyst’s stability and activity. The catalyst and synthesis are exemplified by fabrication of Au nanoparticles doped by Ti atoms that segregate as oxide onto low–coordination sites of edges and vertexes. Pt monolayer shell deposited on Au sites has the mass and specific activities for the oxygen reduction reaction about 13 and 5 times higher than those ofmore » commercial Pt/C catalysts. The durability tests show no activity loss after 10000 potential cycles from 0.6 to 1.0V. The superior activity and durability of the Ti-Au@Pt catalyst originate from protective Ti oxide located at the most dissolution-prone edge and vertex sites, and Au-supported active and stable Pt shell.« less

  6. The type III inositol 1,4,5-trisphosphate receptor preferentially transmits apoptotic Ca2+ signals into mitochondria.

    PubMed

    Mendes, Carolina C P; Gomes, Dawidson A; Thompson, Mayerson; Souto, Natalia C; Goes, Tercio S; Goes, Alfredo M; Rodrigues, Michele A; Gomez, Marcus V; Nathanson, Michael H; Leite, M Fatima

    2005-12-09

    There are three isoforms of the inositol 1,4,5- trisphosphate receptor (InsP(3)R), each of which has a distinct effect on Ca(2+) signaling. However, it is not known whether each isoform similarly plays a distinct role in the activation of Ca(2+)-mediated events. To investigate this question, we examined the effects of each InsP(3)R isoform on transmission of Ca(2+) signals to mitochondria and induction of apoptosis. Each isoform was selectively silenced using isoform-specific small interfering RNA in Chinese hamster ovary cells, which express all three InsP(3)R isoforms. ATP-induced cytosolic Ca(2+) signaling patterns were altered, regardless of which isoform was silenced, but in a different fashion depending on the isoform. ATP also induced Ca(2+) signals in mitochondria, which were inhibited more effectively by silencing the type III InsP(3)R than by silencing either the type I or type II isoform. The type III isoform also co-localized most strongly with mitochondria. When apoptosis was induced by activation of either the extrinsic or intrinsic apoptotic pathway, induction was reduced most effectively by silencing the type III InsP(3)R. These findings provide evidence that the type III isoform of the InsP(3)R plays a special role in induction of apoptosis by preferentially transmitting Ca(2+) signals into mitochondria.

  7. Inhibition of nitric oxide synthase expression in activated microglia and peroxynitrite scavenging activity by Opuntia ficus indica var. saboten.

    PubMed

    Lee, Ming Hong; Kim, Jae Yeon; Yoon, Jeong Hoon; Lim, Hyo Jin; Kim, Tae Hee; Jin, Changbae; Kwak, Wie-Jong; Han, Chang-Kyun; Ryu, Jae-Ha

    2006-09-01

    Activated microglia by neuronal injury or inflammatory stimulation overproduce nitric oxide (NO) by inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) such as superoxide anion, resulting in neurodegenerative diseases. The toxic peroxynitrite (ONOO-), the reaction product of NO and superoxide anion further contributes to oxidative neurotoxicity. A butanol fraction obtained from 50% ethanol extracts of Opuntia ficus indica var. saboten (Cactaceae) stem (SK OFB901) and its hydrolysis product (SK OFB901H) inhibited the production of NO in LPS-activated microglia in a dose dependent manner (IC50 15.9, 4.2 microg/mL, respectively). They also suppressed the expression of protein and mRNA of iNOS in LPS-activated microglial cells at higher than 30 microg/mL as observed by western blot analysis and RT-PCR experiment. They also inhibited the degradation of I-kappaB-alpha in activated microglia. Moreover, they showed strong activity of peroxynitrite scavenging in a cell free bioassay system. These results imply that Opuntia ficus indica may have neuroprotective activity through the inhibition of NO production by activated microglial cells and peroxynitrite scavenging activity. Copyright (c) 2006 John Wiley & Sons, Ltd.

  8. Multiparameter analysis of activated sludge inhibition by nickel, cadmium, and cobalt.

    PubMed

    Hernandez-Martinez, Gabriel R; Ortiz-Alvarez, Daniela; Perez-Roa, Michael; Urbina-Suarez, Nestor Andres; Thalasso, Frederic

    2018-06-05

    Activated sludge processes are often inhibited by nickel, cadmium, and cobalt. The inhibitory effect of these heavy metals on a synthetic wastewater treatment process was tested through pulse microrespirometry; i.e., pulse of substrate injected in a microreactor system. The inhibitory effect was tested under different conditions including the heavy metals, substrate and biomass concentrations, and exposure time. The inhibitory effect was quantified by the percentage of inhibition, half saturation constant (K S ), inhibition constant (K I ), and maximum oxygen uptake rate (OUR max ). The results indicated that, in a range of concentration from 0 to 40 mg L -1 , the three heavy metals exerted an uncompetitive and incomplete inhibitory effect, with a maximum inhibition of 67, 57, and 53% for Ni, Co, and Cd, respectively. An increase of the biomass concentration by 620% resulted in a decrease of the inhibition by 47 and 69% for Co and Cd, respectively, while no effect was observed on Ni inhibition. An increase of the substrate concentration by 87% resulted in an increase of the inhibition by 24, 70, and 47% for Ni, Co and Cd, respectively. In the case of nickel and cadmium, an increase in the exposure time to the heavy metals also increased the inhibition. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Inhibition of parathyroid hormone release by maitotoxin, a calcium channel activator

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fitzpatrick, L.A.; Yasumoto, T.; Aurbach, G.D.

    1989-01-01

    Maitotoxin, a toxin derived from a marine dinoflagellate, is a potent activator of voltage-sensitive calcium channels. To further test the hypothesis that inhibition of PTH secretion by calcium is mediated via a calcium channel we studied the effect of maitotoxin on dispersed bovine parathyroid cells. Maitotoxin inhibited PTH release in a dose-dependent fashion, and inhibition was maximal at 1 ng/ml. Chelation of extracellular calcium by EGTA blocked the inhibition of PTH by maitotoxin. Maitotoxin enhanced the effects of the dihydropyridine calcium channel agonist (+)202-791 and increased the rate of radiocalcium uptake in parathyroid cells. Pertussis toxin, which ADP-ribosylates and inactivatesmore » a guanine nucleotide regulatory protein that interacts with calcium channels in the parathyroid cell, did not affect the inhibition of PTH secretion by maitotoxin. Maitotoxin, by its action on calcium channels allows entry of extracellular calcium and inhibits PTH release. Our results suggest that calcium channels are involved in the release of PTH. Inhibition of PTH release by maitotoxin is not sensitive to pertussis toxin, suggesting that maitotoxin may act distal to the site interacting with a guanine nucleotide regulatory protein, or maitotoxin could interact with other ions or second messengers to inhibit PTH release.« less

  10. Potent inhibition by star fruit of human cytochrome P450 3A (CYP3A) activity.

    PubMed

    Hidaka, Muneaki; Fujita, Ken-ichi; Ogikubo, Tetsuya; Yamasaki, Keishi; Iwakiri, Tomomi; Okumura, Manabu; Kodama, Hirofumi; Arimori, Kazuhiko

    2004-06-01

    There has been very limited information on the capacities of tropical fruits to inhibit human cytochrome P450 3A (CYP3A) activity. Thus, the inhibitory effects of tropical fruits on midazolam 1'-hydroxylase activity of CYP3A in human liver microsomes were evaluated. Eight tropical fruits such as common papaw, dragon fruit, kiwi fruit, mango, passion fruit, pomegranate, rambutan, and star fruit were tested. We also examined the inhibition of CYP3A activity by grapefruit (white) and Valencia orange as controls. The juice of star fruit showed the most potent inhibition of CYP3A. The addition of a star fruit juice (5.0%, v/v) resulted in the almost complete inhibition of midazolam 1'-hydroxylase activity (residual activity of 0.1%). In the case of grape-fruit, the residual activity was 14.7%. The inhibition depended on the amount of fruit juice added to the incubation mixture (0.2-6.0%, v/v). The elongation of the preincubation period of a juice from star fruit (1.25 or 2.5%, v/v) with the microsomal fraction did not alter the CYP3A inhibition, suggesting that the star fruit did not contain a mechanism-based inhibitor. Thus, we discovered filtered extracts of star fruit juice to be inhibitors of human CYP3A activity in vitro.

  11. Inhibition of urease activity in the urinary tract pathogen Staphylococcus saprophyticus.

    PubMed

    Loes, A N; Ruyle, L; Arvizu, M; Gresko, K E; Wilson, A L; Deutch, C E

    2014-01-01

    Urease is a virulence factor for the Gram-positive urinary tract pathogen Staphylococcus saprophyticus. The susceptibility of this enzyme to chemical inhibition was determined using soluble extracts of Staph. saprophyticus strain ATCC 15305. Acetohydroxamic acid (Ki = 8.2 μg ml(-1) = 0.106 mmol l(-1) ) and DL-phenylalanine hydroxamic acid (Ki = 21 μg ml(-1) = 0.116 mmol l(-1) ) inhibited urease activity competitively. The phosphorodiamidate fluorofamide also caused competitive inhibition (Ki = 0.12 μg ml(-1) = 0.553 μmol l(-1) = 0.000553 mmol l(-1) ), but the imidazole omeprazole had no effect. Two flavonoids found in green tea extract [(+)-catechin hydrate (Ki = 357 μg ml(-1) = 1.23 mmol l(-1) ) and (-)-epigallocatechin gallate (Ki = 210 μg ml(-1) = 0.460 mmol l(-1) )] gave mixed inhibition. Acetohydroxamic acid, DL-phenylalanine hydroxamic acid, fluorofamide, (+)-catechin hydrate and (-)-epigallocatechin gallate also inhibited urease activity in whole cells of strains ATCC 15305, ATCC 35552 and ATCC 49907 grown in a rich medium or an artificial urine medium. Addition of acetohydroxamic acid or fluorofamide to cultures of Staph. saprophyticus in an artificial urine medium delayed the increase in pH that normally occurs during growth. These results suggest that urease inhibitors may be useful for treating urinary tract infections caused by Staph. saprophyticus. The enzyme urease is a virulence factor for the Gram-positive urinary tract pathogen Staphylococcus saprophyticus. We have shown that urease activity in cell-free extracts and whole bacterial cells is susceptible to inhibition by hydroxamates, phosphorodiamidates and flavonoids, but not by imidazoles. Acetohydroxamic acid and fluorofamide in particular can temporarily delay the increase in pH that occurs when Staph. saprophyticus is grown in an artificial urine medium. These results suggest that urease inhibitors may be useful as chemotherapeutic agents for the treatment of urinary tract infections

  12. Title VII and Preferential Treatment: Response to EEOC Affirmative Action Guidelines.

    ERIC Educational Resources Information Center

    Schaffrau, Andrew J.

    1979-01-01

    Argues that Title VII prohibits preferential treatment of any group unless ordered by a court pursuant to a judicial finding of unlawful discrimination and unless the preferential treatment is limited to providing relief to judicially identified victims of that discrimination. Available from Georgetown Law Journal, 600 New Jersey Avenue,…

  13. In vitro investigation of anticancer and ACE-inhibiting activity, α-amylase and α-glucosidase inhibition, and antioxidant activity of camel milk fermented with camel milk probiotic: A comparative study with fermented bovine milk.

    PubMed

    Ayyash, Mutamed; Al-Nuaimi, Amna K; Al-Mahadin, Suheir; Liu, Shao-Quan

    2018-01-15

    This study aimed to investigate in vitro the health-promoting benefits (anticancer activity, α-amylase and α-glucosidase inhibition, angiotensin-converting-enzyme (ACE)-inhibition, antioxidant and proteolytic activity) of camel milk fermented with indigenous probiotic strains of Lactobacillus spp., compared with fermented bovine milk. The three camel milk probiotic strains Lb. reuteri-KX881777, Lb. plantarum-KX881772, Lb. plantarum-KX881779 and a control strain Lb. plantarum DSM2468 were employed to ferment camel and bovine milks separately. The proteolytic and antioxidant activity of water soluble extracts (WSEs) from all fermented camel milks were higher than those of fermented bovine milk. α-Amylase inhibition of WSEs were >34% in both milk types fermented with all strains during storage periods, except the WSE of camel milk fermented by Lp.K772. The highest ACE-inhibition of the WSE from camel milk fermented by Lr.K777 was >80%. The proliferations of Caco-2, MCF-7 and HELA cells were more inhibited when treated with the WSE of fermented camel milk. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. IN VITRO CONAZOLE EXPOSURE INHIBITS TESTOSTERONE PRODUCTION IN THE ADULT AND NEONATAL RAT TESTIS THROUGH THE INHIBITION OF CYP17 ACTIVITY

    EPA Science Inventory

    IN VITRO CONAZOLE EXPOSURE INHIBITS TESTOSTERONE PRODUCTION IN THE ADULT AND NEONATAL RAT TESTIS THROUGH THE INHIBITION OF CYP17 ACTIVITY

    Chad R. Blystone1, David J. Dix2, and John C. Rockett2
    1Department of Environmental and Molecular Toxicology, NC State University, R...

  15. Preferential Elimination of Older Erythrocytes in Circulation and Depressed Bone Marrow Erythropoietic Activity Contribute to Cadmium Induced Anemia in Mice

    PubMed Central

    Chatterjee, Sreoshi; Saxena, Rajiv K.

    2015-01-01

    Feeding cadmium chloride (50 or 1000 ppm CdCl2 in drinking water, ad libitum) to C57BL/6 mice resulted in a significant and sustained fall in blood erythrocyte count and hemoglobin levels that started 4 and 3 weeks after the start of 50 and 1000 ppm cadmium doses respectively. A transient yet significant reticulocytosis occurred during the first 4 weeks of cadmium treatment. Using the recently developed double in vivo biotinylation (DIB) technique, turnover of erythrocyte cohorts of different age groups was simultaneously monitored in control and cadmium treated mice. A significant accumulation of younger erythrocytes and a concomitant decline in the relative proportions of older erythrocytes in circulation was observed in both 50 and 1000 ppm cadmium groups indicating that older erythrocytes were preferentially eliminated in cadmium induced anemia. A significant increase in the erythropoietin levels in plasma was seen in mice exposed to 1000 ppm cadmium. Levels of inflammatory cytokines (IL1A, IL6, TNFα, IFNγ) were however not significantly altered in cadmium treated mice. A significant increase in cellular levels of reactive oxygen species (ROS) was observed in older erythrocytes in circulation but not in younger erythrocytes. Erythropoietic activity in the bone marrows and spleens of cadmium treated mice was examined by monitoring the relative proportion of cells belonging to the erythroid line of differentiation in these organs. Erythroid cells in bone marrow declined markedly (about 30%) in mice in the 1000 ppm cadmium group but the decline was not significant in the 50 ppm cadmium group. Cells representing various stages of erythroid differentiation in bone marrow and spleen were enumerated flow cytometrically by double staining with anti-Ter119 and anti-transferrin receptor (CD71) monoclonal antibodies. Decline of erythroid cells was essentially confined to pro-erythroblast and erythroblast-A, along with a concurrent increase in the splenic erythroid

  16. Protein-solvent preferential interactions, protein hydration, and the modulation of biochemical reactions by solvent components.

    PubMed

    Timasheff, Serge N

    2002-07-23

    Solvent additives (cosolvents, osmolytes) modulate biochemical reactions if, during the course of the reaction, there is a change in preferential interactions of solvent components with the reacting system. Preferential interactions can be expressed in terms of preferential binding of the cosolvent or its preferential exclusion (preferential hydration). The driving force is the perturbation by the protein of the chemical potential of the cosolvent. It is shown that the measured change of the amount of water in contact with protein during the course of the reaction modulated by an osmolyte is a change in preferential hydration that is strictly a measure of the cosolvent chemical potential perturbation by the protein in the ternary water-protein-cosolvent system. It is not equal to the change in water of hydration, because water of hydration is a reflection strictly of protein-water forces in a binary system. There is no direct relation between water of preferential hydration and water of hydration.

  17. Differential Regulation of Telomerase Reverse Transcriptase Promoter Activation and Protein Degradation by Histone Deacetylase Inhibition.

    PubMed

    Qing, Hua; Aono, Jun; Findeisen, Hannes M; Jones, Karrie L; Heywood, Elizabeth B; Bruemmer, Dennis

    2016-06-01

    Telomerase reverse transcriptase (TERT) maintains telomeres and is rate limiting for replicative life span. While most somatic tissues silence TERT transcription resulting in telomere shortening, cells derived from cancer or cardiovascular diseases express TERT and activate telomerase. In the present study, we demonstrate that histone deacetylase (HDAC) inhibition induces TERT transcription and promoter activation. At the protein level in contrast, HDAC inhibition decreases TERT protein abundance through enhanced degradation, which decreases telomerase activity and induces senescence. Finally, we demonstrate that HDAC inhibition decreases TERT expression during vascular remodeling in vivo. These data illustrate a differential regulation of TERT transcription and protein stability by HDAC inhibition and suggest that TERT may constitute an important target for the anti-proliferative efficacy of HDAC inhibitors. © 2015 Wiley Periodicals, Inc.

  18. Optimal Fermentation Conditions of Hyaluronidase Inhibition Activity on Asparagus cochinchinensis Merrill by Weissella cibaria.

    PubMed

    Kim, Minji; Kim, Won-Baek; Koo, Kyoung Yoon; Kim, Bo Ram; Kim, Doohyun; Lee, Seoyoun; Son, Hong Joo; Hwang, Dae Youn; Kim, Dong Seob; Lee, Chung Yeoul; Lee, Heeseob

    2017-04-28

    This study was conducted to evaluate the hyaluronidase (HAase) inhibition activity of Asparagus cochinchinesis (AC) extracts following fermentation by Weissella cibaria through response surface methodology. To optimize the HAase inhibition activity, a central composite design was introduced based on four variables: the concentration of AC extract ( X 1 : 1-5%), amount of starter culture ( X 2 : 1-5%), pH ( X 3 : 4-8), and fermentation time ( X 4 : 0-10 days). The experimental data were fitted to quadratic regression equations, the accuracy of the equations was analyzed by ANOVA, and the regression coefficients for the surface quadratic model of HAase inhibition activity in the fermented AC extract were estimated by the F test and the corresponding p values. The HAase inhibition activity indicated that fermentation time was most significant among the parameters within the conditions tested. To validate the model, two different conditions among those generated by the Design Expert program were selected. Under both conditions, predicted and experimental data agreed well. Moreover, the content of protodioscin (a well-known compound related to anti-inflammation activity) was elevated after fermentation of the AC extract at the optimized fermentation condition.

  19. The Probabilistic Nature of Preferential Choice

    ERIC Educational Resources Information Center

    Rieskamp, Jorg

    2008-01-01

    Previous research has developed a variety of theories explaining when and why people's decisions under risk deviate from the standard economic view of expected utility maximization. These theories are limited in their predictive accuracy in that they do not explain the probabilistic nature of preferential choice, that is, why an individual makes…

  20. Preferential expression and function of voltage-gated, O2-sensitive K+ channels in resistance pulmonary arteries explains regional heterogeneity in hypoxic pulmonary vasoconstriction: ionic diversity in smooth muscle cells.

    PubMed

    Archer, Stephen L; Wu, Xi-Chen; Thébaud, Bernard; Nsair, Ali; Bonnet, Sebastien; Tyrrell, Ben; McMurtry, M Sean; Hashimoto, Kyoko; Harry, Gwyneth; Michelakis, Evangelos D

    2004-08-06

    Hypoxic pulmonary vasoconstriction (HPV) is initiated by inhibition of O2-sensitive, voltage-gated (Kv) channels in pulmonary arterial smooth muscle cells (PASMCs). Kv inhibition depolarizes membrane potential (E(M)), thereby activating Ca2+ influx via voltage-gated Ca2+ channels. HPV is weak in extrapulmonary, conduit pulmonary arteries (PA) and strong in precapillary resistance arteries. We hypothesized that regional heterogeneity in HPV reflects a longitudinal gradient in the function/expression of PASMC O2-sensitive Kv channels. In adult male Sprague Dawley rats, constrictions to hypoxia, the Kv blocker 4-aminopyridine (4-AP), and correolide, a Kv1.x channel inhibitor, were endothelium-independent and greater in resistance versus conduit PAs. Moreover, HPV was dependent on Kv-inhibition, being completely inhibited by pretreatment with 4-AP. Kv1.2, 1.5, Kv2.1, Kv3.1b, Kv4.3, and Kv9.3. mRNA increased as arterial caliber decreased; however, only Kv1.5 protein expression was greater in resistance PAs. Resistance PASMCs had greater K+ current (I(K)) and a more hyperpolarized E(M) and were uniquely O2- and correolide-sensitive. The O2-sensitive current (active at -65 mV) was resistant to iberiotoxin, with minimal tityustoxin sensitivity. In resistance PASMCs, 4-AP and hypoxia inhibited I(K) 57% and 49%, respectively, versus 34% for correolide. Intracellular administration of anti-Kv1.5 antibodies inhibited correolide's effects. The hypoxia-sensitive, correolide-insensitive I(K) (15%) was conducted by Kv2.1. Anti-Kv1.5 and anti-Kv2.1 caused additive depolarization in resistance PASMCs (Kv1.5>Kv2.1) and inhibited hypoxic depolarization. Heterologously expressed human PASMC Kv1.5 generated an O2- and correolide-sensitive I(K) like that in resistance PASMCs. In conclusion, Kv1.5 and Kv2.1 account for virtually all the O2-sensitive current. HPV occurs in a Kv-enriched resistance zone because resistance PASMCs preferentially express O2-sensitive Kv-channels.

  1. Selective inhibition by harmane of the apurinic apyrimidinic endonuclease activity of phage T4-induced UV endonuclease.

    PubMed

    Warner, H R; Persson, M L; Bensen, R J; Mosbaugh, D W; Linn, S

    1981-11-25

    1-Methyl-9H-pyrido-[3,4-b]indole (harmane) inhibits the apurinic/apyrimidinic (AP) endonuclease activity of the UV endonuclease induced by phage T4, whereas it stimulates the pyrimidine dimer-DNA glycosylase activity of that enzyme. E. coli endonuclease IV, E. coli endonuclease VI (the AP endonuclease activity associated with E. coli exonuclease III), and E. coli uracil-DNA glycosylase were not inhibited by harmane. Human fibroblast AP endonucleases I and II also were only slightly inhibited. Therefore, harmane is neither a general inhibitor of AP endonucleases, nor a general inhibitor of Class I AP endonucleases which incise DNA on the 3'-side of AP sites. However, E. coli endonuclease III and its associated dihydroxythymine-DNA glycosylase activity were both inhibited by harmane. This observation suggests that harmane may inhibit only AP endonucleases which have associated glycosylase activities.

  2. Selective inhibition by harmane of the apurinic apyrimidinic endonuclease activity of phage T4-induced UV endonuclease.

    PubMed Central

    Warner, H R; Persson, M L; Bensen, R J; Mosbaugh, D W; Linn, S

    1981-01-01

    1-Methyl-9H-pyrido-[3,4-b]indole (harmane) inhibits the apurinic/apyrimidinic (AP) endonuclease activity of the UV endonuclease induced by phage T4, whereas it stimulates the pyrimidine dimer-DNA glycosylase activity of that enzyme. E. coli endonuclease IV, E. coli endonuclease VI (the AP endonuclease activity associated with E. coli exonuclease III), and E. coli uracil-DNA glycosylase were not inhibited by harmane. Human fibroblast AP endonucleases I and II also were only slightly inhibited. Therefore, harmane is neither a general inhibitor of AP endonucleases, nor a general inhibitor of Class I AP endonucleases which incise DNA on the 3'-side of AP sites. However, E. coli endonuclease III and its associated dihydroxythymine-DNA glycosylase activity were both inhibited by harmane. This observation suggests that harmane may inhibit only AP endonucleases which have associated glycosylase activities. PMID:6273822

  3. Salicylate, diflunisal and their metabolites inhibit CBP/p300 and exhibit anticancer activity.

    PubMed

    Shirakawa, Kotaro; Wang, Lan; Man, Na; Maksimoska, Jasna; Sorum, Alexander W; Lim, Hyung W; Lee, Intelly S; Shimazu, Tadahiro; Newman, John C; Schröder, Sebastian; Ott, Melanie; Marmorstein, Ronen; Meier, Jordan; Nimer, Stephen; Verdin, Eric

    2016-05-31

    Salicylate and acetylsalicylic acid are potent and widely used anti-inflammatory drugs. They are thought to exert their therapeutic effects through multiple mechanisms, including the inhibition of cyclo-oxygenases, modulation of NF-κB activity, and direct activation of AMPK. However, the full spectrum of their activities is incompletely understood. Here we show that salicylate specifically inhibits CBP and p300 lysine acetyltransferase activity in vitro by direct competition with acetyl-Coenzyme A at the catalytic site. We used a chemical structure-similarity search to identify another anti-inflammatory drug, diflunisal, that inhibits p300 more potently than salicylate. At concentrations attainable in human plasma after oral administration, both salicylate and diflunisal blocked the acetylation of lysine residues on histone and non-histone proteins in cells. Finally, we found that diflunisal suppressed the growth of p300-dependent leukemia cell lines expressing AML1-ETO fusion protein in vitro and in vivo. These results highlight a novel epigenetic regulatory mechanism of action for salicylate and derivative drugs.

  4. Network state-dependent inhibition of identified hippocampal CA3 axo-axonic cells in vivo

    PubMed Central

    Tukker, John J; Klausberger, Thomas; Somogyi, Peter

    2015-01-01

    Hippocampal sharp waves are population discharges initiated by an unknown mechanism in pyramidal cell networks of CA3. Axo-axonic cells (AACs) regulate action potential generation through GABAergic synapses on the axon initial segment. We found that CA3 AACs in anesthetized rats and AACs in freely moving rats stopped firing during sharp waves, when pyramidal cells fire most. AACs fired strongly and rhythmically around the peak of theta oscillations, when pyramidal cells fire at low probability. Distinguishing AACs from other parvalbumin-expressing interneurons by their lack of detectable SATB1 transcription factor immunoreactivity, we discovered a somatic GABAergic input originating from the medial septum that preferentially targets AACs. We recorded septo-hippocampal GABAergic cells that were activated during hippocampal sharp waves and projected to CA3. We hypothesize that inhibition of AACs, and the resulting subcellular redistribution of inhibition from the axon initial segment to other pyramidal cell domains, is a necessary condition for the emergence of sharp waves promoting memory consolidation. PMID:24141313

  5. TES inhibits colorectal cancer progression through activation of p38.

    PubMed

    Li, Huili; Huang, Kun; Gao, Lu; Wang, Lixia; Niu, Yanfeng; Liu, Hongli; Wang, Zheng; Wang, Lin; Wang, Guobin; Wang, Jiliang

    2016-07-19

    The human TESTIN (TES) gene has been identified as a candidate tumor suppressor based on its location at a common fragile site - a region where loss of heterozygosity has been detected in numerous types of tumors. To investigate its role in colorectal cancer (CRC), we examined TES protein levels in CRC tissue samples and cell lines. We observed that TES was markedly reduced in both CRC tissue and cell lines. Additionally, overexpression of TES significantly inhibited cell proliferation, migration, and invasion, while increasing cell apoptosis in colon cancer cells. By contrast, shRNA-mediated TES knockdown elicited the opposite effects. TES inhibited the progression of CRC by up-regulating pro-apoptotic proteins, down-regulating anti-apoptotic proteins, and simultaneously activating p38 mitogen-activated protein kinase (MAPK) signaling pathways. Collectively, these data indicate that TES functions as a necessary suppressor of CRC progression by activating p38-MAPK signaling pathways. This suggests that TES may have a potential application in CRC diagnosis and targeted gene therapy.

  6. Apigenin Restricts FMDV Infection and Inhibits Viral IRES Driven Translational Activity

    PubMed Central

    Qian, Suhong; Fan, Wenchun; Qian, Ping; Zhang, Dong; Wei, Yurong; Chen, Huanchun; Li, Xiangmin

    2015-01-01

    Foot-and-mouth disease (FMD) is a highly contagious disease of domestic and wild ruminants that is caused by FMD virus (FMDV). FMD outbreaks have occurred in livestock-containing regions worldwide. Apigenin, which is a flavonoid naturally existing in plant, possesses various pharmacological effects, including anti-inflammatory, anticancer, antioxidant and antiviral activities. Results show that apigenin can inhibit FMDV-mediated cytopathogenic effect and FMDV replication in vitro. Further studies demonstrate the following: (i) apigenin inhibits FMDV infection at the viral post-entry stage; (ii) apigenin does not exhibit direct extracellular virucidal activity; and (iii) apigenin interferes with the translational activity of FMDV driven by internal ribosome entry site. Studies on applying apigein in vivo are required for drug development and further identification of potential drug targets against FDMV infection. PMID:25835532

  7. Apigenin restricts FMDV infection and inhibits viral IRES driven translational activity.

    PubMed

    Qian, Suhong; Fan, Wenchun; Qian, Ping; Zhang, Dong; Wei, Yurong; Chen, Huanchun; Li, Xiangmin

    2015-03-31

    Foot-and-mouth disease (FMD) is a highly contagious disease of domestic and wild ruminants that is caused by FMD virus (FMDV). FMD outbreaks have occurred in livestock-containing regions worldwide. Apigenin, which is a flavonoid naturally existing in plant, possesses various pharmacological effects, including anti-inflammatory, anticancer, antioxidant and antiviral activities. Results show that apigenin can inhibit FMDV-mediated cytopathogenic effect and FMDV replication in vitro. Further studies demonstrate the following: (i) apigenin inhibits FMDV infection at the viral post-entry stage; (ii) apigenin does not exhibit direct extracellular virucidal activity; and (iii) apigenin interferes with the translational activity of FMDV driven by internal ribosome entry site. Studies on applying apigein in vivo are required for drug development and further identification of potential drug targets against FDMV infection.

  8. Rapid Feedforward Inhibition and Asynchronous Excitation Regulate Granule Cell Activity in the Mammalian Main Olfactory Bulb

    PubMed Central

    Burton, Shawn D.

    2015-01-01

    Granule cell-mediated inhibition is critical to patterning principal neuron activity in the olfactory bulb, and perturbation of synaptic input to granule cells significantly alters olfactory-guided behavior. Despite the critical role of granule cells in olfaction, little is known about how sensory input recruits granule cells. Here, we combined whole-cell patch-clamp electrophysiology in acute mouse olfactory bulb slices with biophysical multicompartmental modeling to investigate the synaptic basis of granule cell recruitment. Physiological activation of sensory afferents within single glomeruli evoked diverse modes of granule cell activity, including subthreshold depolarization, spikelets, and suprathreshold responses with widely distributed spike latencies. The generation of these diverse activity modes depended, in part, on the asynchronous time course of synaptic excitation onto granule cells, which lasted several hundred milliseconds. In addition to asynchronous excitation, each granule cell also received synchronous feedforward inhibition. This inhibition targeted both proximal somatodendritic and distal apical dendritic domains of granule cells, was reliably recruited across sniff rhythms, and scaled in strength with excitation as more glomeruli were activated. Feedforward inhibition onto granule cells originated from deep short-axon cells, which responded to glomerular activation with highly reliable, short-latency firing consistent with tufted cell-mediated excitation. Simulations showed that feedforward inhibition interacts with asynchronous excitation to broaden granule cell spike latency distributions and significantly attenuates granule cell depolarization within local subcellular compartments. Collectively, our results thus identify feedforward inhibition onto granule cells as a core feature of olfactory bulb circuitry and establish asynchronous excitation and feedforward inhibition as critical regulators of granule cell activity. SIGNIFICANCE

  9. Whey peptide Isoleucine-Tryptophan inhibits expression and activity of matrix metalloproteinase-2 in rat aorta.

    PubMed

    Kopaliani, Irakli; Martin, Melanie; Zatschler, Birgit; Müller, Bianca; Deussen, Andreas

    2016-08-01

    Aortic stiffness is an independent risk factor for development of cardiovascular diseases. Activation of renin-angiotensin-aldosterone system (RAAS) including angiotensin converting enzyme (ACE) activity leads to overproduction of angiotensin II (ANGII) from its precursor angiotensin I (ANGI). ANGII leads to overexpression and activation of matrix metalloproteinase-2 (MMP2), which is critically associated with pathophysiology of aortic stiffness. We previously reported that the whey peptide Isoleucine-Tryptophan (IW) acts as a potent ACE inhibitor. Herein, we critically elucidate the mechanism of action by which IW causes inhibition of expression and activity of MMP2 in aortic tissue. Effects of IW on expression and activity of MMP2 were assessed on endothelial and smooth muscle cells (ECs and SMCs) in vitro and ex vivo (isolated rat aorta). As controls we used the pharmaceutical ACE inhibitor - captopril and the ANGII type 1 receptor blocker - losartan. In vitro, both ANGII and ANGI stimulation significantly (P<0.01) increased expression of MMP2 assessed with western blot. Similarly, to captopril IW significantly (P<0.05) inhibited ANGI, but not ANGII mediated increase in expression of MMP2, while losartan also blocked effects of ANGII. Signaling pathways regulating MMP2 expression in ECs and SMCs were similarly inhibited after treatment with IW or captopril. In ECs IW significantly (P<0.05) inhibited JNK pathway, whereas in SMCs JAK2/STAT3 pathway, assessed with western blot. In vitro findings were fully consistent with results in isolated rat aorta ex vivo. Moreover, IW not only inhibited the MMP2 expression, but also its activation assessed with gelatin zymography. Our findings demonstrate that IW effectively inhibits expression and activation of MMP2 in rat aorta by decreasing local conversion of ANGI to ANGII. Thus, similar to pharmaceutical ACE inhibitor captopril the dipeptide IW may effectively inhibit ACE activity and prevent the age and hypertension

  10. Stokes Approach to Preferential Flow at the Darcy-Scale

    NASA Astrophysics Data System (ADS)

    Germann, Peter; Bogner, Christina

    2017-04-01

    Preferential Flow in soils is fast, limited to infiltration and occupies but a small portion of porosity. However, how fast is it, how much water is involved, what is its flow rate, and how far is it carried? Supported with numerous measurements a Stokes approach to preferential flow provides the answers at the operational Darcy-scale. The approach to preferential flow in permeable media (pm) stresses momentum dissipation during viscous flow. Thus, a laminar water film percolates through a pm. The dynamic film is initially determined by the thickness F (m) and the specific contact area L (m2 m-3) per unit volume of the medium. Input to the medium's surface is a pulse with volume flux density q (ms-1) that starts and ends at times TB and TE. A specific pulse and the intrinsic properties of a pm determine F and L. A water content wave (WCW) envelops the spatio-temporal evolution of a water film. A WCW is completely described with a set of analytical relationships that are based on F, L, and the water's viscosity. The approach is an extension of Hagen-Poiseuille's law of flow in concentric conduits. It also evolves seamlessly from extending Darcy's law into non-saturated pm. Experimental determination of F and L follows either from drainage flow or from rapid soil moisture recordings during the passing of a WCW, for instance, with TDR-equipment. Parameters from numerous infiltration experiments in the field, in soil columns, in sand boxes, and lysimeters demonstrate the approach's broad applicability, thus framing the spatio-temporal extensions, velocities and volume flux densities of preferential flows. The specific contact area L is considered the locus of water, heat, particle and solute transfer between a WCW and the sessile parts of a pm. A recent analysis of delayed Br-breakthrough with respect to drainage flow supports the feasibility of the Stokes approach to preferential flow at the Darcy-scale. A perspective of modeling sequences of input pulses will

  11. Preferential aerosolization of bacteria in bioaerosols generated in vitro.

    PubMed

    Perrott, P; Turgeon, N; Gauthier-Levesque, L; Duchaine, C

    2017-09-01

    Little is known about how bacteria are aerosolized in terms of whether some bacteria will be found in the air more readily than others that are present in the source. This report describes in vitro experiments to compare aerosolization rates (also known as preferential aerosolization) of Gram-positive and Gram-negative bacteria as well as rod- and coccus-shaped bacteria, using two nebulization conditions. A consortium of five bacterial species was aerosolized in a homemade chamber. Aerosols generated with a commercial nebulizer and a homemade bubble-burst aerosol generator were compared. Data suggest that Pseudomonas aeruginosa was preferentially aerosolized in comparison to Moraxella catarrhalis, Lactobacillus paracasei, Staphylococcus aureus and Streptococcus suis, independently of the method of aerosolization. Bacterial integrity of Strep. suis was more preserved compared to other bacteria studied as revealed with PMA-qPCR. We reported the design of an aerosol chamber and bubble-burst generator for the in vitro study of preferential aerosolization. In our setting, preferential aerosolization was influenced by bacterial properties instead of aerosolization mechanism. These findings could have important implications for predicting the composition of bioaerosols in various locations such as wastewater treatment plants, agricultural settings and health care settings. © 2017 The Society for Applied Microbiology.

  12. Inhibition of APOBEC3G Activity Impedes Double-Strand DNA Repair

    PubMed Central

    Prabhu, Ponnandy; Shandilya, Shivender; Britan-Rosich, Elena; Nagler, Adi; Schiffer, Celia A.; Kotler, Moshe

    2015-01-01

    The cellular cytidine deaminase APOBEC3G (A3G) was first described as an anti-HIV-1 restriction factor by directly deaminating reverse transcripts of the viral genome. HIV-1 Vif neutralizes the activity of A3G, primarily by mediating degradation of A3G to establish effective infection in host target cells. Lymphoma cells, which express high amounts of A3G, can restrict Vif-deficient HIV-1. Interestingly, these cells are more stable in the face of treatments that result in dsDNA damage, such as ionizing irradiation (IR) and chemotherapies. Previously, we showed that the Vif-derived peptide (Vif25-39) efficiently inhibits A3G deamination, and increases sensitivity of lymphoma cells to IR. In the current study, we show that additional peptides derived from Vif, A3G and A3F, which contain the LYYF motif, inhibit deamination activity. Each residue in the Vif25-39 sequence moderately contributes to the inhibitory effect, while, replacing a single amino acid in the LYYF motif completely abrogate inhibition of deamination. Treatment of A3G-expressing lymphoma cells exposed to ionizing radiation with the new inhibitory peptides reduces double-strand break (DSB) repair after radiation. Incubation of cultured irradiated lymphoma cells with peptides that inhibit DSB repair halts their propagation. These results suggest that A3G may be a potential therapeutic target amenable to peptide and peptidomimetic inhibition. PMID:26460502

  13. Inhibition of APOBEC3G activity impedes double-stranded DNA repair.

    PubMed

    Prabhu, Ponnandy; Shandilya, Shivender M D; Britan-Rosich, Elena; Nagler, Adi; Schiffer, Celia A; Kotler, Moshe

    2016-01-01

    The cellular cytidine deaminase APOBEC3G (A3G) was first described as an anti-HIV-1 restriction factor, acting by directly deaminating reverse transcripts of the viral genome. HIV-1 Vif neutralizes the activity of A3G, primarily by mediating degradation of A3G to establish effective infection in host target cells. Lymphoma cells, which express high amounts of A3G, can restrict Vif-deficient HIV-1. Interestingly, these cells are more stable in the face of treatments that result in double-stranded DNA damage, such as ionizing radiation and chemotherapies. Previously, we showed that the Vif-derived peptide (Vif25-39) efficiently inhibits A3G deamination, and increases the sensitivity of lymphoma cells to ionizing radiation. In the current study, we show that additional peptides derived from Vif, A3G, and APOBEC3F, which contain the LYYF motif, inhibit deamination activity. Each residue in the Vif25-39 sequence moderately contributes to the inhibitory effect, whereas replacing a single residue in the LYYF motif completely abrogates inhibition of deamination. Treatment of A3G-expressing lymphoma cells exposed to ionizing radiation with the new inhibitory peptides reduces double-strand break repair after irradiation. Incubation of cultured irradiated lymphoma cells with peptides that inhibit double-strand break repair halts their propagation. These results suggest that A3G may be a potential therapeutic target that is amenable to peptide and peptidomimetic inhibition. © 2015 FEBS.

  14. 3,3′-Diindolylmethane, but not indole-3-carbinol, inhibits histone deacetylase activity in prostate cancer cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Beaver, Laura M., E-mail: beaverl@onid.orst.edu; School of Biological and Population Health Sciences, Oregon State University, 103 Milam Hall, Corvallis, OR 97331; Yu, Tian-Wei, E-mail: david.yu@oregonstate.edu

    2012-09-15

    Increased consumption of cruciferous vegetables is associated with a reduced risk of developing prostate cancer. Indole-3-carbinol (I3C) and 3,3′-diindolylmethane (DIM) are phytochemicals derived from cruciferous vegetables that have shown promise in inhibiting prostate cancer in experimental models. Histone deacetylase (HDAC) inhibition is an emerging target for cancer prevention and therapy. We sought to examine the effects of I3C and DIM on HDACs in human prostate cancer cell lines: androgen insensitive PC-3 cells and androgen sensitive LNCaP cells. I3C modestly inhibited HDAC activity in LNCaP cells by 25% but no inhibition of HDAC activity was detected in PC-3 cells. In contrast,more » DIM significantly inhibited HDAC activity in both cell lines by as much as 66%. Decreases in HDAC activity correlated with increased expression of p21, a known target of HDAC inhibitors. DIM treatment caused a significant decrease in the expression of HDAC2 protein in both cancer cell lines but no significant change in the protein levels of HDAC1, HDAC3, HDAC4, HDAC6 or HDAC8 was detected. Taken together, these results show that inhibition of HDAC activity by DIM may contribute to the phytochemicals' anti-proliferative effects in the prostate. The ability of DIM to target aberrant epigenetic patterns, in addition to its effects on detoxification of carcinogens, may make it an effective chemopreventive agent by targeting multiple stages of prostate carcinogenesis. -- Highlights: ► DIM inhibits HDAC activity and decreases HDAC2 expression in prostate cancer cells. ► DIM is significantly more effective than I3C at inhibiting HDAC activity. ► I3C has no effect on HDAC protein expression. ► Inhibition of HDAC activity by DIM is associated with increased p21 expression. ► HDAC inhibition may be a novel epigenetic mechanism for cancer prevention with DIM.« less

  15. Voluntary strategy suppresses the positive impact of preferential selection in prisoner’s dilemma

    NASA Astrophysics Data System (ADS)

    Sun, Lei; Lin, Pei-jie; Chen, Ya-shan

    2014-11-01

    Impact of aspiration is ubiquitous in social and biological disciplines. In this work, we try to explore the impact of such a trait on voluntary prisoners’ dilemma game via a selection parameter w. w=0 returns the traditional version of random selection. For positive w, the opponent of high payoff will be selected; while negative w means that the partner of low payoff will be chosen. We find that for positive w, cooperation will be greatly promoted in the interval of small b, at variance cooperation is inhibited with large b. For negative w, cooperation is fully restrained, irrespective of b value. It is found that the positive impact of preferential selection is suppressed by the voluntary strategy in prisoner’s dilemma. These observations can be supported by the spatial patterns. Our work may shed light on the emergence and persistence of cooperation with voluntary participation in social dilemma.

  16. Citral inhibits lipopolysaccharide-induced acute lung injury by activating PPAR-γ.

    PubMed

    Shen, Yongbin; Sun, Zhanfeng; Guo, Xiaotong

    2015-01-15

    Citral, a component of lemongrass oil, has been reported to have many pharmacological activities such as anti-bacterial and anti-inflammatory effects. However, the effects of citral on acute lung injury (ALI) and the molecular mechanisms have not been reported. The aim of this study was to detect the effects of citral on lipopolysaccharide (LPS)-induced acute lung injury and investigate the molecular mechanisms. LPS-induced acute lung injury model was used to detect the anti-inflammatory effect of citral in vivo. The alveolar macrophages were used to investigate the molecular mechanism of citral in vitro. The results showed that pretreatment with citral remarkably attenuated pulmonary edema, histological severities, TNF-α, IL-6 and IL-1β production in LPS-induced ALI in vivo. In vitro, citral inhibited LPS-induced TNF-α, IL-6 and IL-1β production in alveolar macrophages. LPS-induced NF-κB activation was also inhibited by citral. Furthermore, we found that citral activated PPAR-γ and the anti-inflammatory effects of citral can be reversed by PPAR-γ antagonist GW9662. In conclusion, this is the first to demonstrate that citral protects LPS-induced ALI in mice. The anti-inflammatory mechanism of citral is associated with activating PPAR-γ, thereby inhibiting LPS-induced inflammatory response. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Ligand activation of peroxisome proliferator-activated receptor-beta/delta inhibits cell proliferation in human HaCaT keratinocytes.

    PubMed

    Borland, Michael G; Foreman, Jennifer E; Girroir, Elizabeth E; Zolfaghari, Reza; Sharma, Arun K; Amin, Shantu; Gonzalez, Frank J; Ross, A Catharine; Peters, Jeffrey M

    2008-11-01

    Although there is strong evidence that ligand activation of peroxisome proliferator-activated receptor (PPAR)-beta/delta induces terminal differentiation and attenuates cell growth, some studies suggest that PPARbeta/delta actually enhances cell proliferation. For example, it was suggested recently that retinoic acid (RA) is a ligand for PPARbeta/delta and potentiates cell proliferation by activating PPARbeta/delta. The present study examined the effect of ligand activation of PPARbeta/delta on cell proliferation, cell cycle kinetics, and target gene expression in human HaCaT keratinocytes using two highly specific PPARbeta/delta ligands [4-[[[2-[3-fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy acetic acid (GW0742) and 2-methyl-4-((4-methyl-2-(4-trifluoromethylphenyl)-1,3-thiazol-5-yl)-methylsulfanyl)phenoxy-acetic acid (GW501516)] and RA. Both PPARbeta/delta ligands and RA inhibited cell proliferation of HaCaT keratinocytes. GW0742 and GW501516 increased expression of known PPARbeta/delta target genes, whereas RA did not; RA increased the expression of known retinoic acid receptor/retinoid X receptor target genes, whereas GW0742 did not affect these genes. GW0742, GW501516, and RA did not modulate the expression of 3-phosphoinositide-dependent protein kinase or alter protein kinase B phosphorylation. GW0742 and RA increased annexin V staining as quantitatively determined by flow cytometry. The effects of GW0742 and RA were also examined in wild-type and PPARbeta/delta-null primary mouse keratinocytes to determine the specific role of PPARbeta/delta in modulating cell growth. Although inhibition of keratinocyte proliferation by GW0742 was PPARbeta/delta-dependent, inhibition of cell proliferation by RA occurred in both genotypes. Results from these studies demonstrate that ligand activation of PPARbeta/delta inhibits keratinocyte proliferation through PPARbeta/delta-dependent mechanisms. In contrast, the observed inhibition of

  18. Cloning and characterization of an RNase-related protein gene preferentially expressed in rice stems.

    PubMed

    Wei, Jun-Ya; Li, An-Ming; Li, Yin; Wang, Jing; Liu, Xiao-Bin; Liu, Liang-Shi; Xu, Zeng-Fu

    2006-04-01

    RNase-related proteins (RRPs) are S- and S-like RNase homologs lacking the active site required for RNase activity. Here we describe the cloning and characterization of the rice (Oryza sativa) RRP gene (OsRRP). A single copy of OsRRP occurs in the rice genome. OsRRP contains three introns and an open reading frame encoding 252 amino acids, with the replacement of two histidines involved in the active site of RNase by lysine and tyrosine respectively. OsRRP is preferentially expressed in stems of wild-type rice and is significantly down-regulated in an increased tillering dwarf mutant ext37.

  19. Allosteric auto-inhibition and activation of the Nedd4 family E3 ligase Itch.

    PubMed

    Zhu, Kang; Shan, Zelin; Chen, Xing; Cai, Yuqun; Cui, Lei; Yao, Weiyi; Wang, Zhen; Shi, Pan; Tian, Changlin; Lou, Jizhong; Xie, Yunli; Wen, Wenyu

    2017-09-01

    The Nedd4 family E3 ligases are key regulators of cell growth and proliferation and are often misregulated in human cancers and other diseases. The ligase activities of Nedd4 E3s are tightly controlled via auto-inhibition. However, the molecular mechanism underlying Nedd4 E3 auto-inhibition and activation is poorly understood. Here, we show that the WW domains proceeding the catalytic HECT domain play an inhibitory role by binding directly to HECT in the Nedd4 E3 family member Itch. Our structural and biochemical analyses of Itch reveal that the WW2 domain and a following linker allosterically lock HECT in an inactive state inhibiting E2-E3 transthiolation. Binding of the Ndfip1 adaptor or JNK1-mediated phosphorylation relieves the auto-inhibition of Itch in a WW2-dependent manner. Aberrant activation of Itch leads to migration defects of cortical neurons during development. Our study provides a new mechanism governing the regulation of Itch. © 2017 The Authors.

  20. Role of nuclear factor of activated T-cells and activator protein-1 in the inhibition of interleukin-2 gene transcription by cannabinol in EL4 T-cells.

    PubMed

    Yea, S S; Yang, K H; Kaminski, N E

    2000-02-01

    We previously reported that immunosuppressive cannabinoids inhibited interleukin (IL)-2 steady-state mRNA expression and secretion by phorbol-12-myristate-13-acetate plus ionomycin-activated mouse splenocytes and EL4 murine T-cells. Here we show that inhibition of IL-2 production by cannabinol, a modest central nervous system-active cannabinoid, is mediated through the inhibition of IL-2 gene transcription. Moreover, electrophoretic mobility shift assays demonstrated that cannabinol markedly inhibited the DNA binding activity of nuclear factor of activated T-cells (NF-AT) and activator protein-1 (AP-1) in a time- and concentration-dependent manner in activated EL4 cells. The inhibitory effects produced by cannabinol on AP-1 DNA binding were quite transient, showing partial recovery by 240 min after cell activation and no effect on the activity of a reporter gene under the control of AP-1. Conversely, cannabinol-mediated inhibition of NF-AT was robust and sustained as demonstrated by an NF-AT-regulated reporter gene. Collectively, these results suggest that decreased IL-2 production by cannabinol in EL4 cells is due to the inhibition of transcriptional activation of the IL-2 gene and is mediated, at least in part, through a transient inhibition of AP-1 and a sustained inhibition of NF-AT.

  1. CYTOTOXIC, α-CHYMOTRYPSIN AND UREASE INHIBITION ACTIVITIES OF THE PLANT Heliotropium dasycarpum L.

    PubMed

    Ghaffari, Muhammad Abuzar; Chaudhary, Bashir Ahmed; Uzair, Muhammad; Ashfaq, Khuram

    2016-01-01

    The aim of this study was to investigate Cytotoxic, α-Chymotrypsin and Urease inhibition activities of the plant Heliotropium dasycarpum . Dichloromethane and methanol extracts of the plant were evaluated for cytotoxic, α-Chymotrypsin and Urease inhibition by using in vivo Brine Shrimp lethality bioassay and in vitro enzymatic inhibition assays respectively. The methanol extract of the plant exhibited significant cytotoxic activity. Out of 30 brine shrimp larvae, 2 (6%), 26 (86%) and 28 (93%) larvae were survived at concentration of 1000μg/ml, 100μg/ml and 10μg/ml respectively with LD50; 215.837. Similarly 21 (70%), 25 (83%), 29 (96%) larvae were survived of dichloromethane plant extract with LD50; 6170.64. The methanol and dichloromethane extract exhibited 10.50±0.18% and 41.51±0.15% α-chymotrypsin enzyme inhibition respectively with IC 50 values of greater than 500 μmol. The methanol extract showed 24.39±0.21% Urease enzyme inhibition with IC 50 values of greater than 400 μmol While dichloromethane extract has 11.46±0.09% enzyme inhibition with IC 50 values of greater than 500 μmol. The results clearly indicated that Heliotropium dasycarpum has cytotoxic potential and enzyme inhibition properties. Further study is needed to screen out antitumor and anti-ulcerative agents.

  2. CYTOTOXIC, α-CHYMOTRYPSIN AND UREASE INHIBITION ACTIVITIES OF THE PLANT Heliotropium dasycarpum L.

    PubMed Central

    Ghaffari, Muhammad Abuzar; Chaudhary, Bashir Ahmed; Uzair, Muhammad; Ashfaq, Khuram

    2016-01-01

    Background: The aim of this study was to investigate Cytotoxic, α-Chymotrypsin and Urease inhibition activities of the plant Heliotropium dasycarpum. Materials & Methods: Dichloromethane and methanol extracts of the plant were evaluated for cytotoxic, α-Chymotrypsin and Urease inhibition by using in vivo Brine Shrimp lethality bioassay and in vitro enzymatic inhibition assays respectively. Results: The methanol extract of the plant exhibited significant cytotoxic activity. Out of 30 brine shrimp larvae, 2 (6%), 26 (86%) and 28 (93%) larvae were survived at concentration of 1000μg/ml, 100μg/ml and 10μg/ml respectively with LD50; 215.837. Similarly 21 (70%), 25 (83%), 29 (96%) larvae were survived of dichloromethane plant extract with LD50; 6170.64. The methanol and dichloromethane extract exhibited 10.50±0.18% and 41.51±0.15% α-chymotrypsin enzyme inhibition respectively with IC50 values of greater than 500 μmol. The methanol extract showed 24.39±0.21% Urease enzyme inhibition with IC50 values of greater than 400 μmol While dichloromethane extract has 11.46±0.09% enzyme inhibition with IC50 values of greater than 500 μmol Conclusion: The results clearly indicated that Heliotropium dasycarpum has cytotoxic potential and enzyme inhibition properties. Further study is needed to screen out antitumor and anti-ulcerative agents. PMID:28480379

  3. Antioxidant, Antityrosinase, Anticholinesterase, and Nitric Oxide Inhibition Activities of Three Malaysian Macaranga Species

    PubMed Central

    Abas, Faridah; Ahmad, Syahida; Shaari, Khozirah; Khamis, Shamsul; Lajis, N. H.

    2013-01-01

    The methanol extracts of three Macaranga species (M. denticulata, M. pruinosa, and M. gigantea) were screened to evaluate their total phenolic contents and activities as cholinesterase inhibitors, nitric oxide (NO) production inhibitors, tyrosinase inhibitors, and antioxidants. The bark of M. denticulata showed the highest total phenolic content (2682 mg gallic acid equivalent (GAE)/100 g) and free radical scavenging activity (IC50 = 0.063 mg/mL). All of the samples inhibited linoleic acid peroxidation by greater than 80%, with the leaves of M. gigantea exhibiting the highest inhibition of 92.21%. Most of the samples exhibited significant antioxidant potential. The bark of M. denticulata and the leaves of both M. pruinosa and M. gigantea exhibited greater than 50% tyrosinase inhibition, with the bark of M. denticulata having the highest percentage of inhibition (68.7%). The bark and leaves of M. denticulata exhibited greater than 50% inhibition (73.82% and 54.50%, resp.) of the acetylcholinesterase enzyme (AChE), while none of the samples showed any significant inhibition of butyrylcholinesterase (BChE). Only the bark of M. denticulata and M. gigantea displayed greater than 50% inhibition of nitric oxide production in cells (81.79% and 56.51%, resp.). These bioactivities indicate that some Macaranga spp. have therapeutic potential in medicinal research. PMID:24319356

  4. Phenolic compounds from Citrus leaves: antioxidant activity and enzymatic browning inhibition.

    PubMed

    Khettal, Bachra; Kadri, Nabil; Tighilet, Karim; Adjebli, Ahmed; Dahmoune, Farid; Maiza-Benabdeslam, Fadila

    2017-03-01

    Background Phenolic compounds from Citrus are known to be a topic of many studies due to their biological properties including antioxidant activity. Methods Methanolic and aqueous extracts were isolated from Citrus leaves of different species (C. clementina, C. limon, C. hamlin, C. navel, C. aurantifolia, C. aurantium and C. grandis) harvested in Algeria. Results The results showed that aqueous extracts of all species are rich in total phenolic compounds and flavonoids (from 68.23 to 125.28 mg GAE/g DM) and (from 11.99 to 46.25 mg QE/g DM) respectively. The methanolic and aqueous extracts were examined for in vitro antioxidant properties using various antioxidant assays. For aqueous extracts, C. limon showed an important DPPH radical scavenging activity (IC50 35.35 µg/mL), and C. clementina exerted the highest ABTS radical scavenging activity (1,174.43 µM ET/g DM) and a significant ferric reducing potential (30.60 mg BHAE/g DM). For methanolic extracts, C. clementina showed the highest antioxidant activity for all the realized assays (IC50 41.85 µg/mL, 378.63 µM ET/g DM and 13.85 mg BHAE/g DM) for DPPH, ABTS radicals scavenging activities and ferric reducing potential respectively. Antiperoxidase and antipolyphenol oxidase activities of these samples were also evaluated. Conclusions In this investigation, the assessment of antiperoxidase activity proved that the leaves extracts of different species were able to inhibit peroxidase activity. However, this inhibition varied with the species and the source of these enzymes. On the other hand, the aqueous extracts of different species showed moderate inhibition of polyphenol oxidase, while no effect on these enzymes was obtained with methanolic extracts.

  5. Preferentially Cytotoxic Constituents of Andrographis paniculata and their Preferential Cytotoxicity against Human Pancreatic Cancer Cell Lines.

    PubMed

    Lee, Sullim; Morita, Hiroyuki; Tezuka, Yasuhiro

    2015-07-01

    In the course of our search for anticancer agents based on a novel anti-austerity strategy, we found that the 70% EtOH extract of the crude drug Andrographis Herba (aerial parts of Andrographis paniculata), used in Japanese Kampo medicines, killed PANC-1 human pancreatic cancer cells preferentially in nutrient-deprived medium (NDM). Phytochemical investigation of the 70% EtOH extract led to the isolation of 21 known compounds consisting of six labdane-type diterpenes (11, 15, 17-19, 21), six flavones (5, 7, 10, 12, 14, 20), three flavanones (2, 6, 16), two sterols (3, 8), a fatty acid (1), a phthalate (4), a triterpene (9), and a monoterpene (13). Among them, 14-deoxy-11,12-didehydroandrographolide (17) displayed the most potent preferential cytotoxicity against PANC-1 and PSN-1 cells with PC50 values of 10.0 μM and 9.27 μM, respectively. Microscopical observation, double staining with ethidium bromide (EB) and acridine orange (AO), and flow cytometry with propidium iodide/annexin V double staining indicated that 14-deoxy-11,12-didehydroandrographolide (17) triggered apoptosis-like cell death in NDM with an amino acids and/or serum-sensitive mode.

  6. Salicylates inhibit flavivirus replication independently of blocking nuclear factor kappa B activation.

    PubMed

    Liao, C L; Lin, Y L; Wu, B C; Tsao, C H; Wang, M C; Liu, C I; Huang, Y L; Chen, J H; Wang, J P; Chen, L K

    2001-09-01

    Flaviviruses comprise a positive-sense RNA genome that replicates exclusively in the cytoplasm of infected cells. Whether flaviviruses require an activated nuclear factor(s) to complete their life cycle and trigger apoptosis in infected cells remains elusive. Flavivirus infections quickly activate nuclear factor kappa B (NF-kappaB), and salicylates have been shown to inhibit NF-kappaB activation. In this study, we investigated whether salicylates suppress flavivirus replication and virus-induced apoptosis in cultured cells. In a dose-dependent inhibition, we found salicylates within a range of 1 to 5 mM not only restricted flavivirus replication but also abrogated flavivirus-triggered apoptosis. However, flavivirus replication was not affected by a specific NF-kappaB peptide inhibitor, SN50, and a proteosome inhibitor, lactacystin. Flaviviruses also replicated and triggered apoptosis in cells stably expressing IkappaBalpha-DeltaN, a dominant-negative mutant that antagonizes NF-kappaB activation, as readily as in wild-type BHK-21 cells, suggesting that NF-kappaB activation is not essential for either flavivirus replication or flavivirus-induced apoptosis. Salicylates still diminished flavivirus replication and blocked apoptosis in the same IkappaBalpha-DeltaN cells. This inhibition of flaviviruses by salicylates could be partially reversed by a specific p38 mitogen-activated protein (MAP) kinase inhibitor, SB203580. Together, these results show that the mechanism by which salicylates suppress flavivirus infection may involve p38 MAP kinase activity but is independent of blocking the NF-kappaB pathway.

  7. Postsynaptic activity reverses the sign of the acetylcholine-induced long-term plasticity of GABAA inhibition

    PubMed Central

    Domínguez, Soledad; Fernández de Sevilla, David; Buño, Washington

    2014-01-01

    Acetylcholine (ACh) regulates forms of plasticity that control cognitive functions but the underlying mechanisms remain largely unknown. ACh controls the intrinsic excitability, as well as the synaptic excitation and inhibition of CA1 hippocampal pyramidal cells (PCs), cells known to participate in circuits involved in cognition and spatial navigation. However, how ACh regulates inhibition in function of postsynaptic activity has not been well studied. Here we show that in rat PCs, a brief pulse of ACh or a brief stimulation of cholinergic septal fibers combined with repeated depolarization induces strong long-term enhancement of GABAA inhibition (GABAA-LTP). Indeed, this enhanced inhibition is due to the increased activation of α5βγ2 subunit-containing GABAA receptors by the GABA released. GABAA-LTP requires the activation of M1-muscarinic receptors and an increase in cytosolic Ca2+. In the absence of PC depolarization ACh triggered a presynaptic depolarization-induced suppression of inhibition (DSI), revealing that postsynaptic activity gates the effects of ACh from presynaptic DSI to postsynaptic LTP. These results provide key insights into mechanisms potentially linked with cognitive functions, spatial navigation, and the homeostatic control of abnormal hyperexcitable states. PMID:24938789

  8. Self-reported impulsivity, but not behavioral approach or inhibition, mediates the relationship between stress and self-control

    PubMed Central

    Hamilton, Kristen R.; Sinha, Rajita; Potenza, Marc N.

    2014-01-01

    Stress has been associated with poor self-control. Individual differences in impulsivity and other behavioral tendencies may influence the relationship of stress with self-control, although this possibility has not been examined to date. The present research investigated whether cumulative stress is associated with poor self-control, and whether this relationship is mediated by impulsivity, behavioral approach, and behavioral inhibition in men and women. A community sample of 566 adults (319 women and 247 men) was assessed on the Cumulative Adversity Interview, Brief Self-control Scale, Barratt Impulsivity Scale, and Behavioral Activation System and Behavioral Inhibition System Scale (BIS/BAS). Data were analyzed using regression and bootstrapping techniques. In the total sample, the effects of cumulative stress on self-control were mediated by impulsivity. Neither behavioral inhibition nor behavioral approach mediated the association between cumulative stress and self-control in the total sample. Results were similar when men and women were considered separately, with impulsivity, but not behavioral inhibition or approach, mediating the association between cumulative stress and self-control. Impulsive individuals might benefit preferentially from interventions focusing on stress management and strategies for improving self-control. PMID:24508183

  9. Self-reported impulsivity, but not behavioral approach or inhibition, mediates the relationship between stress and self-control.

    PubMed

    Hamilton, Kristen R; Sinha, Rajita; Potenza, Marc N

    2014-11-01

    Stress has been associated with poor self-control. Individual differences in impulsivity and other behavioral tendencies may influence the relationship of stress with self-control, although this possibility has not been examined to date. The present research investigated whether cumulative stress is associated with poor self-control, and whether this relationship is mediated by impulsivity, behavioral approach, and behavioral inhibition in men and women. A community sample of 566 adults (319 women and 247 men) was assessed on the Cumulative Adversity Interview, Brief Self-control Scale, Barratt Impulsivity Scale, and Behavioral Activation System and Behavioral Inhibition System Scale (BIS/BAS). Data were analyzed using regression and bootstrapping techniques. In the total sample, the effects of cumulative stress on self-control were mediated by impulsivity. Neither behavioral inhibition nor behavioral approach mediated the association between cumulative stress and self-control in the total sample. Results were similar when men and women were considered separately, with impulsivity, but not behavioral inhibition or approach, mediating the association between cumulative stress and self-control. Impulsive individuals might benefit preferentially from interventions focusing on stress management and strategies for improving self-control. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Effects of memantine on the excitation-inhibition balance in prefrontal cortex

    PubMed Central

    Povysheva, Nadezhda V.; Johnson, Jon W.

    2016-01-01

    Memantine is one of the few drugs currently approved for treatment of Alzheimer’s disease (AD). The clinical effects of memantine are thought to be associated with inhibition of NMDA receptors (NMDARs). Surprisingly, other open-channel NMDAR blockers have unacceptable side effects that prevent their consideration for AD treatment. One of the mechanisms proposed to explain the therapeutic benefits of memantine involves preferential decrease of excitatory drive to inhibitory neurons in the cortical circuitry and consequent changes in balance between excitation and inhibition (E/I). In this study we addressed effects of memantine on E/I balance in the prefrontal cortex (PFC). We found that a moderate concentration of memantine shifted E/I balance away from inhibition in the PFC circuitry. Indeed, memantine decreased the frequency and amplitude of spontaneous inhibitory postsynaptic currents in pyramidal neurons while leaving spontaneous excitatory postsynaptic currents unaffected. These circuitry effects of memantine were occluded by the competitive NMDAR inhibitor AP-5, and thus are associated with NMDAR inhibition. We also found that memantine decreased feed-forward disynaptic inhibitory input to pyramidal neurons, which is thought to be mediated by parvalbumin (PV)-positive interneurons. Accordingly, memantine caused a greater decrease of the amplitude of NMDAR-mediated synaptic responses in PV-positive interneurons than in pyramidal neurons. Finally, memantine reduced firing activity in PV-positive interneurons while increasing firing in pyramidal neurons. This study elucidates a novel mechanism of action of memantine associated with shifting of the E/I balance away from inhibition in neocortical circuitry, and provides important insights for AD drug development. PMID:27546057

  11. α7 Nicotinic Acetylcholine Receptor Signaling Inhibits Inflammasome Activation by Preventing Mitochondrial DNA Release

    PubMed Central

    Lu, Ben; Kwan, Kevin; Levine, Yaakov A; Olofsson, Peder S; Yang, Huan; Li, Jianhua; Joshi, Sonia; Wang, Haichao; Andersson, Ulf; Chavan, Sangeeta S; Tracey, Kevin J

    2014-01-01

    The mammalian immune system and the nervous system coevolved under the influence of cellular and environmental stress. Cellular stress is associated with changes in immunity and activation of the NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome, a key component of innate immunity. Here we show that α7 nicotinic acetylcholine receptor (α7 nAchR)-signaling inhibits inflammasome activation and prevents release of mitochondrial DNA, an NLRP3 ligand. Cholinergic receptor agonists or vagus nerve stimulation significantly inhibits inflammasome activation, whereas genetic deletion of α7 nAchR significantly enhances inflammasome activation. Acetylcholine accumulates in macrophage cytoplasm after adenosine triphosphate (ATP) stimulation in an α7 nAchR-independent manner. Acetylcholine significantly attenuated calcium or hydrogen oxide–induced mitochondrial damage and mitochondrial DNA release. Together, these findings reveal a novel neurotransmitter-mediated signaling pathway: acetylcholine translocates into the cytoplasm of immune cells during inflammation and inhibits NLRP3 inflammasome activation by preventing mitochondrial DNA release. PMID:24849809

  12. Cytostatic versus Cytocidal Activities of Chloroquine Analogues and Inhibition of Hemozoin Crystal Growth

    PubMed Central

    Gorka, Alexander P.; Alumasa, John N.; Sherlach, Katy S.; Jacobs, Lauren M.; Nickley, Katherine B.; Brower, Jonathan P.; de Dios, Angel C.

    2013-01-01

    We report an improved, nonhazardous, high-throughput assay for in vitro quantification of antimalarial drug inhibition of β-hematin (hemozoin) crystallization performed under conditions that are more physiological relative to previous assays. The assay uses the differential detergent solubility of crystalline and noncrystalline forms of heme and is optimized via the use of lipid catalyst. Using this assay, we quantify the effect of pH on the crystal growth-inhibitory activities of current quinoline antimalarials, evaluate the catalytic efficiencies of different lipids, and test for a possible correlation between hemozoin inhibition by drugs versus their antiplasmodial activity. Consistent with several previous reports, we found a good correlation between hemozoin inhibition potency versus cytostatic antiplasmodial potency (50% inhibitory concentration) for a series of chloroquine (CQ) analogues. However, we found no correlation between hemozoin inhibition potency and cytocidal antiplasmodial potency (50% lethal dose) for the same drugs, suggesting that cellular targets for these two layers of 4-aminoquinoline drug activity differ. This important concept is also explored further for QN and its stereoisomers in the accompanying paper (A. P. Gorka, K. S. Sherlach, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:365–374, 2013). PMID:23114783

  13. Cytostatic versus cytocidal activities of chloroquine analogues and inhibition of hemozoin crystal growth.

    PubMed

    Gorka, Alexander P; Alumasa, John N; Sherlach, Katy S; Jacobs, Lauren M; Nickley, Katherine B; Brower, Jonathan P; de Dios, Angel C; Roepe, Paul D

    2013-01-01

    We report an improved, nonhazardous, high-throughput assay for in vitro quantification of antimalarial drug inhibition of β-hematin (hemozoin) crystallization performed under conditions that are more physiological relative to previous assays. The assay uses the differential detergent solubility of crystalline and noncrystalline forms of heme and is optimized via the use of lipid catalyst. Using this assay, we quantify the effect of pH on the crystal growth-inhibitory activities of current quinoline antimalarials, evaluate the catalytic efficiencies of different lipids, and test for a possible correlation between hemozoin inhibition by drugs versus their antiplasmodial activity. Consistent with several previous reports, we found a good correlation between hemozoin inhibition potency versus cytostatic antiplasmodial potency (50% inhibitory concentration) for a series of chloroquine (CQ) analogues. However, we found no correlation between hemozoin inhibition potency and cytocidal antiplasmodial potency (50% lethal dose) for the same drugs, suggesting that cellular targets for these two layers of 4-aminoquinoline drug activity differ. This important concept is also explored further for QN and its stereoisomers in the accompanying paper (A. P. Gorka, K. S. Sherlach, A. C. de Dios, and P. D. Roepe, Antimicrob. Agents Chemother. 57:365-374, 2013).

  14. Potent inhibition of human neutrophil activations by bractelactone, a novel chalcone from Fissistigma bracteolatum

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wu, Yang-Chang; Graduate Institute of Integrated Medicine, College of Chinese Medicine, China Medical University, Taichung 404, Taiwan; Sureshbabu, Munisamy

    Fissistigma bracteolatum is widely used in traditional medicine to treat inflammatory diseases. However, its active components and mechanisms of action remain unclear. In this study, (3Z)-6,7-dihydroxy-4-methoxy-3-(phenylmethylidene)-5-(3-phenylpropanoyl) -1-benzofuran-2(3H) (bractelactone), a novel chalcone from F. bracteolatum, showed potent inhibitory effects against superoxide anion (O{sub 2}{sup ·−}) production, elastase release, and CD11b expression in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-induced human neutrophils. However, bractelactone showed only weak inhibition of phorbol myristate acetate-caused O{sub 2}{sup ·−} production. The peak cytosolic calcium concentration ([Ca{sup 2+}]{sub i}) was unaltered by bractelactone in FMLP-induced neutrophils, but the decay time of [Ca{sup 2+}]{sub i} was significantly shortened. In a calcium-free solution, changesmore » in [Ca{sup 2+}]{sub i} caused by the addition of extracellular Ca{sup 2+} were inhibited by bractelactone in FMLP-activated cells. In addition, bractelactone did not alter the phosphorylation of p38 MAPK, ERK, JNK, or AKT or the concentration of cAMP. These results suggest that bractelactone selectively inhibits store-operated calcium entry (SOCE). In agreement with this concept, bractelactone suppressed sustained [Ca{sup 2+}]{sub i} changes in thapsigargin-activated neutrophils. Furthermore, bractelactone did not alter FMLP-induced formation of inositol 1,4,5-triphosphate. Taken together, our results demonstrate that the anti-inflammatory effects of bractelactone, an active ingredient of F. bracteolatum, in human neutrophils are through the selective inhibition of SOCE. Highlights: ► Bractelactone isolated from Fissistigma bracteolatum. ► Bractelactone inhibited FMLP-induced human neutrophil activations. ► Bractelactone had no effect on IP3 formation. ► Bractelactone did not alter MAPKs, AKT, and cAMP pathways. ► Bractelactone inhibited store-operated calcium entry.« less

  15. A novel sulfate-reducing bacteria detection method based on inhibition of cysteine protease activity.

    PubMed

    Qi, Peng; Zhang, Dun; Wan, Yi

    2014-11-01

    Sulfate-reducing bacteria (SRB) have been extensively studied in corrosion and environmental science. However, fast enumeration of SRB population is still a difficult task. This work presents a novel specific SRB detection method based on inhibition of cysteine protease activity. The hydrolytic activity of cysteine protease was inhibited by taking advantage of sulfide, the characteristic metabolic product of SRB, to attack active cysteine thiol group in cysteine protease catalytic sites. The active thiol S-sulfhydration process could be used for SRB detection, since the amount of sulfide accumulated in culture medium was highly related with initial bacterial concentration. The working conditions of cysteine protease have been optimized to obtain better detection capability, and the SRB detection performances have been evaluated in this work. The proposed SRB detection method based on inhibition of cysteine protease activity avoided the use of biological recognition elements. In addition, compared with the widely used most probable number (MPN) method which would take up to at least 15days to accomplish whole detection process, the method based on inhibition of papain activity could detect SRB in 2 days, with a detection limit of 5.21×10(2) cfu mL(-1). The detection time for SRB population quantitative analysis was greatly shortened. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Optical resolution by preferential crystallization of (RS)-2-benzoylamino-2-benzyl-3-hydroxypropanoic acid and its use in synthesizing optically active 2-amino-2-methyl-3-phenylpropanoic acid.

    PubMed

    Shiraiwa, Tadashi; Suzuki, Masahiro; Sakai, Yoshio; Nagasawa, Hisashi; Takatani, Kazuhiro; Noshi, Daisuke; Yamanashi, Kenji

    2002-10-01

    To synthesize optically active 2-amino-2-methyl-3-phenylpropanoic acid (1), (RS)-2-benzoylamino-2-benzyl-3-hydroxypropanoic acid [(RS)-2] was first optically resolved using cinchonidine as a resolving agent to yield optically pure (S)- and (R)-2 in yields of about 70%, based on half of the starting amount of (RS)-2. Next, the racemic structure of (RS)-2 was examined based on melting point, solubility, IR spectrum, and binary and ternary phase diagrams, with the aim of optical resolution by preferential crystallization of (RS)-2. Results indicated that the (RS)-2 exists as a conglomerate at room temperature, although it forms a racemic compound at the melting point. The optical resolution by preferential crystallization yielded (S)- and (R)-2 with optical purities of about 90%, which were fully purified by recrystallization. After O-tosylation of (S)- and (R)-2, reduction by zinc powder and sodium iodide gave (R)- and (S)-1, respectively.

  17. Inhibition of estrogen-responsive gene activation by the retinoid X receptor beta: evidence for multiple inhibitory pathways.

    PubMed

    Segars, J H; Marks, M S; Hirschfeld, S; Driggers, P H; Martinez, E; Grippo, J F; Brown, M; Wahli, W; Ozato, K

    1993-04-01

    The retinoid X receptor beta (RXR beta; H-2RIIBP) forms heterodimers with various nuclear hormone receptors and binds multiple hormone response elements, including the estrogen response element (ERE). In this report, we show that endogenous RXR beta contributes to ERE binding activity in nuclear extracts of the human breast cancer cell line MCF-7. To define a possible regulatory role of RXR beta regarding estrogen-responsive transcription in breast cancer cells, RXR beta and a reporter gene driven by the vitellogenin A2 ERE were transfected into estrogen-treated MCF-7 cells. RXR beta inhibited ERE-driven reporter activity in a dose-dependent and element-specific fashion. This inhibition occurred in the absence of the RXR ligand 9-cis retinoic acid. The RXR beta-induced inhibition was specific for estrogen receptor (ER)-mediated ERE activation because inhibition was observed in ER-negative MDA-MB-231 cells only following transfection of the estrogen-activated ER. No inhibition of the basal reporter activity was observed. The inhibition was not caused by simple competition of RXR beta with the ER for ERE binding, since deletion mutants retaining DNA binding activity but lacking the N-terminal or C-terminal domain failed to inhibit reporter activity. In addition, cross-linking studies indicated the presence of an auxiliary nuclear factor present in MCF-7 cells that contributed to RXR beta binding of the ERE. Studies using known heterodimerization partners of RXR beta confirmed that RXR beta/triiodothyronine receptor alpha heterodimers avidly bind the ERE but revealed the existence of another triiodothyronine-independent pathway of ERE inhibition. These results indicate that estrogen-responsive genes may be negatively regulated by RXR beta through two distinct pathways.

  18. Optogenetic Activation of the Sublaterodorsal (SLD) Nucleus Induces Rapid Muscle Inhibition

    DTIC Science & Technology

    2015-09-01

    ARL-CR-0783 ● SEP 2015 US Army Research Laboratory Optogenetic Activation of the Sublaterodorsal (SLD) Nucleus Induces Rapid...ARL-CR-0783 ● SEP 2015 US Army Research Laboratory Optogenetic Activation of the Sublaterodorsal (SLD) Nucleus Induces Rapid Muscle...Optogenetic Activation of the Sublaterodorsal (SLD) Nucleus Induces Rapid Muscle Inhibition 5a. CONTRACT NUMBER 1120-1120-99 5b. GRANT NUMBER 5c

  19. KSHV inhibits stress granule formation by viral ORF57 blocking PKR activation

    PubMed Central

    Sharma, Nishi R.; Majerciak, Vladimir; Kruhlak, Michael J.

    2017-01-01

    TIA-1 positive stress granules (SG) represent the storage sites of stalled mRNAs and are often associated with the cellular antiviral response. In this report, we provide evidence that Kaposi’s sarcoma-associated herpesvirus (KSHV) overcomes the host antiviral response by inhibition of SG formation via a viral lytic protein ORF57. By immunofluorescence analysis, we found that B lymphocytes with KSHV lytic infection are refractory to SG induction. KSHV ORF57, an essential post-transcriptional regulator of viral gene expression and the production of new viral progeny, inhibits SG formation induced experimentally by arsenite and poly I:C, but not by heat stress. KSHV ORF37 (vSOX) bearing intrinsic endoribonuclease activity also inhibits arsenite-induced SG formation, but KSHV RTA, vIRF-2, ORF45, ORF59 and LANA exert no such function. ORF57 binds both PKR-activating protein (PACT) and protein kinase R (PKR) through their RNA-binding motifs and prevents PACT-PKR interaction in the PKR pathway which inhibits KSHV production. Consistently, knocking down PKR expression significantly promotes KSHV virion production. ORF57 interacts with PKR to inhibit PKR binding dsRNA and its autophosphorylation, leading to inhibition of eIF2α phosphorylation and SG formation. Homologous protein HSV-1 ICP27, but not EBV EB2, resembles KSHV ORF57 in the ability to block the PKR/eIF2α/SG pathway. In addition, KSHV ORF57 inhibits poly I:C-induced TLR3 phosphorylation. Altogether, our data provide the first evidence that KSHV ORF57 plays a role in modulating PKR/eIF2α/SG axis and enhances virus production during virus lytic infection. PMID:29084250

  20. Effect of atherosclerosis on endothelium-dependent inhibition of platelet activation in humans.

    PubMed

    Diodati, J G; Dakak, N; Gilligan, D M; Quyyumi, A A

    1998-07-07

    We investigated whether luminal release of nitric oxide (NO) contributes to inhibition of platelet activation and whether these effects are reduced in patients with atherosclerosis. Femoral blood flow velocity and ex vivo whole blood platelet aggregation by impedance aggregometry were measured in femoral venous blood during femoral arterial infusion of acetylcholine (ACh; 30 microg/min) in 30 patients, 19 of whom had angiographic atherosclerosis. Measurements were repeated with sodium nitroprusside (40 microg/min), L-arginine (160 micromol/min), and N(G)-monomethyl-L-arginine (L-NMMA; 16 micromol/min). There was significant inhibition of collagen-induced platelet aggregation with ACh (45+/-9.5% lower, P<0.001), and this inhibition was greater in patients without atherosclerosis (68.7+/-10.4% reduction) than in those with atherosclerosis (32.5+/-8.1%, P=0.04). The magnitude of inhibition correlated with vasodilation with ACh, indicating an association between the smooth muscle and antiplatelet effects of endothelium-dependent stimulation. Neither L-NMMA nor sodium nitroprusside altered platelet aggregation. L-Arginine inhibited platelet aggregation equally in vitro (34+/-8% reduction, P<0.01) and in vivo (37+/-13% reduction, P<0.01). Stimulation of NO release into the vascular lumen with ACh inhibits platelet aggregation, an effect that is attenuated in patients with atherosclerosis and endothelial dysfunction. Basal NO release does not appear to contribute to platelet passivation in vivo. L-Arginine inhibited platelet aggregation by its direct action on platelets. These findings provide a pathophysiological basis for the observed increase in thrombotic events in atherosclerosis. Use of L-arginine and other strategies to improve endothelial NO activity may impact favorably on thrombotic events in atherosclerosis.

  1. Gremlin inhibits UV-induced skin cell damages via activating VEGFR2-Nrf2 signaling

    PubMed Central

    Xu, Qiu-yun; Zhang, Jing; Lin, Meng-ting; Tu, Ying; He, Li; Bi, Zhi-gang; Cheng, Bo

    2016-01-01

    Ultra Violet (UV) radiation induces reactive oxygen species (ROS) production, DNA oxidation and single strand breaks (SSBs), which will eventually lead to skin cell damages or even skin cancer. Here, we tested the potential activity of gremlin, a novel vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) agonist, against UV-induced skin cell damages. We show that gremlin activated VEGFR2 and significantly inhibited UV-induced death and apoptosis of skin keratinocytes and fibroblasts. Pharmacological inhibition or shRNA-mediated knockdown of VEGFR2 almost abolished gremlin-mediated cytoprotection against UV in the skin cells. Further studies showed that gremlin activated VEGFR2 downstream NF-E2-related factor 2 (Nrf2) signaling, which appeared required for subsequent skin cell protection. Nrf2 shRNA knockdown or S40T dominant negative mutation largely inhibited gremlin-mediated skin cell protection against UV. At last, we show that gremlin dramatically inhibited UV-induced ROS production and DNA SSB formation in skin keratinocytes and fibroblasts. We conclude that gremlin protects skin cells from UV damages via activating VEGFR2-Nrf2 signaling. Gremlin could be further tested as a novel anti-UV skin protectant. PMID:27713170

  2. Gremlin inhibits UV-induced skin cell damages via activating VEGFR2-Nrf2 signaling.

    PubMed

    Ji, Chao; Huang, Jin-Wen; Xu, Qiu-Yun; Zhang, Jing; Lin, Meng-Ting; Tu, Ying; He, Li; Bi, Zhi-Gang; Cheng, Bo

    2016-12-20

    Ultra Violet (UV) radiation induces reactive oxygen species (ROS) production, DNA oxidation and single strand breaks (SSBs), which will eventually lead to skin cell damages or even skin cancer. Here, we tested the potential activity of gremlin, a novel vascular endothelial growth factor (VEGF) receptor 2 (VEGFR2) agonist, against UV-induced skin cell damages. We show that gremlin activated VEGFR2 and significantly inhibited UV-induced death and apoptosis of skin keratinocytes and fibroblasts. Pharmacological inhibition or shRNA-mediated knockdown of VEGFR2 almost abolished gremlin-mediated cytoprotection against UV in the skin cells. Further studies showed that gremlin activated VEGFR2 downstream NF-E2-related factor 2 (Nrf2) signaling, which appeared required for subsequent skin cell protection. Nrf2 shRNA knockdown or S40T dominant negative mutation largely inhibited gremlin-mediated skin cell protection against UV. At last, we show that gremlin dramatically inhibited UV-induced ROS production and DNA SSB formation in skin keratinocytes and fibroblasts. We conclude that gremlin protects skin cells from UV damages via activating VEGFR2-Nrf2 signaling. Gremlin could be further tested as a novel anti-UV skin protectant.

  3. Biofilm inhibition of spoilage bacteria by Argentinean fruit juices with antihypertensive activity.

    PubMed

    Vallejo, Claudia V; Aredes-Fernández, Pedro A; Farías, Marta E; Rodríguez-Vaquero, María J

    2013-01-01

    Argentinean juices have been studied for their antihypertensive activity, the inhibition of bacteria biofilm formation and the effect on the viability of wine yeast. The influence of phenolic compounds on these activities was evaluated. These studies are the first step for the development of a new type of wine that includes grape must supplement with fruit juices with antihypertensive effect. All juices posses a high antihypertensive activity, higher than 50%. Strawberry juices and eureka lemon showed the highest activity, whereas clarified juices posses the lowest activity. All studied juices produce a high inhibition of bacteria biofilm formation, and the strawberry, orange and mandarin varieties not affect the growth or viability of yeast. Our results permit to conclude that it could be possible the use of these juices in a new type of wine or as a source of new antihypertensive agents for pharmaceutical industry.

  4. Emergence of Soft Communities from Geometric Preferential Attachment

    PubMed Central

    Zuev, Konstantin; Boguñá, Marián; Bianconi, Ginestra; Krioukov, Dmitri

    2015-01-01

    All real networks are different, but many have some structural properties in common. There seems to be no consensus on what the most common properties are, but scale-free degree distributions, strong clustering, and community structure are frequently mentioned without question. Surprisingly, there exists no simple generative mechanism explaining all the three properties at once in growing networks. Here we show how latent network geometry coupled with preferential attachment of nodes to this geometry fills this gap. We call this mechanism geometric preferential attachment (GPA), and validate it against the Internet. GPA gives rise to soft communities that provide a different perspective on the community structure in networks. The connections between GPA and cosmological models, including inflation, are also discussed. PMID:25923110

  5. Determining the frequency, depth and velocity of preferential flow by high frequency soil moisture monitoring

    NASA Astrophysics Data System (ADS)

    Hardie, Marcus; Lisson, Shaun; Doyle, Richard; Cotching, William

    2013-01-01

    Preferential flow in agricultural soils has been demonstrated to result in agrochemical mobilisation to shallow ground water. Land managers and environmental regulators need simple cost effective techniques for identifying soil - land use combinations in which preferential flow occurs. Existing techniques for identifying preferential flow have a range of limitations including; often being destructive, non in situ, small sampling volumes, or are subject to artificial boundary conditions. This study demonstrated that high frequency soil moisture monitoring using a multi-sensory capacitance probe mounted within a vertically rammed access tube, was able to determine the occurrence, depth, and wetting front velocity of preferential flow events following rainfall. Occurrence of preferential flow was not related to either rainfall intensity or rainfall amount, rather preferential flow occurred when antecedent soil moisture content was below 226 mm soil moisture storage (0-70 cm). Results indicate that high temporal frequency soil moisture monitoring may be used to identify soil type - land use combinations in which the presence of preferential flow increases the risk of shallow groundwater contamination by rapid transport of agrochemicals through the soil profile. However use of high frequency based soil moisture monitoring to determine agrochemical mobilisation risk may be limited by, inability to determine the volume of preferential flow, difficulty observing macropore flow at high antecedent soil moisture content, and creation of artificial voids during installation of access tubes in stony soils.

  6. Salicylate, diflunisal and their metabolites inhibit CBP/p300 and exhibit anticancer activity

    PubMed Central

    Shirakawa, Kotaro; Wang, Lan; Man, Na; Maksimoska, Jasna; Sorum, Alexander W; Lim, Hyung W; Lee, Intelly S; Shimazu, Tadahiro; Newman, John C; Schröder, Sebastian; Ott, Melanie; Marmorstein, Ronen; Meier, Jordan; Nimer, Stephen; Verdin, Eric

    2016-01-01

    Salicylate and acetylsalicylic acid are potent and widely used anti-inflammatory drugs. They are thought to exert their therapeutic effects through multiple mechanisms, including the inhibition of cyclo-oxygenases, modulation of NF-κB activity, and direct activation of AMPK. However, the full spectrum of their activities is incompletely understood. Here we show that salicylate specifically inhibits CBP and p300 lysine acetyltransferase activity in vitro by direct competition with acetyl-Coenzyme A at the catalytic site. We used a chemical structure-similarity search to identify another anti-inflammatory drug, diflunisal, that inhibits p300 more potently than salicylate. At concentrations attainable in human plasma after oral administration, both salicylate and diflunisal blocked the acetylation of lysine residues on histone and non-histone proteins in cells. Finally, we found that diflunisal suppressed the growth of p300-dependent leukemia cell lines expressing AML1-ETO fusion protein in vitro and in vivo. These results highlight a novel epigenetic regulatory mechanism of action for salicylate and derivative drugs. DOI: http://dx.doi.org/10.7554/eLife.11156.001 PMID:27244239

  7. Nesfatin-1 inhibits ovarian epithelial carcinoma cell proliferation in vitro

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Xu, Yang; Pang, Xiaoyan; Dong, Mei

    Highlights: •Nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest. •Nesfatin-1 enhances HO-8910 cell apoptosis. •Nesfatin-1 inhibits HO-8910 cell proliferation via mTOR and RhoA/ROCK signaling pathway. •The first report of nesfatin-1-mediated proliferation in ovarian epithelial carcinoma. -- Abstract: Nesfatin-1, an 82-amino-acid peptide derived from a 396-amino-acid precursor protein nucleobindin 2 (NUCB2), was originally identified in hypothalamic nuclei involved in the regulation of food intake. It was recently reported that nesfatin-1 is a novel depot specific adipokine preferentially produced by subcutaneous tissue, with obesity- and food deprivation-regulated expression. Although a relation between ovarian cancer mortality and obesitymore » has been previously established, a role of nesfatin-1 in ovarian epithelial carcinoma remains unknown. The aim of the present study is to examine the effect of nesfatin-1 on ovary carcinoma cells proliferation. We found that nesfatin-1 inhibits the proliferation and growth of HO-8910 cells by G1 phase arrest, this inhibition could be abolished by nesfatin-1 neutralizing antibody. Nesfatin-1 enhances HO-8910 cell apoptosis, activation of mammalian target of rapamycin (mTOR) and RhoA/ROCK signaling pathway block the effects of nesfatin-1-induced apoptosis, therefore reverses the inhibition of HO-8910 cell proliferation by nesfatin-1. In conclusion, the present study demonstrated that nesfatin-1 can inhibit the proliferation in human ovarian epithelial carcinoma cell line HO-8910 cells through inducing apoptosis via mTOR and RhoA/ROCK signaling pathway. This study provides a novel regulatory signaling pathway of nesfatin-1-regulated ovarian epithelial carcinoma growth and may contribute to ovarian cancer prevention and therapy, especially in obese patients.« less

  8. Chronic inhibition of Ca(2+)/calmodulin kinase II activity in the pilocarpine model of epilepsy.

    PubMed

    Churn, S B; Kochan, L D; DeLorenzo, R J

    2000-09-01

    The development of symptomatic epilepsy is a model of long-term plasticity changes in the central nervous system. The rat pilocarpine model of epilepsy was utilized to study persistent alterations in calcium/calmodulin-dependent kinase II (CaM kinase II) activity associated with epileptogenesis. CaM kinase II-dependent substrate phosphorylation and autophosphorylation were significantly inhibited for up to 6 weeks following epileptogenesis in both the cortex and hippocampus, but not in the cerebellum. The net decrease in CaM kinase II autophosphorylation and substrate phosphorylation was shown to be due to decreased kinase activity and not due to increased phosphatase activity. The inhibition in CaM kinase II activity and the development of epilepsy were blocked by pretreating seizure rats with MK-801 indicating that the long-lasting decrease in CaM kinase II activity was dependent on N-methyl-D-aspartate receptor activation. In addition, the inhibition of CaM kinase II activity was associated in time and regional localization with the development of spontaneous recurrent seizure activity. The decrease in enzyme activity was not attributed to a decrease in the alpha or beta kinase subunit protein expression level. Thus, the significant inhibition of the enzyme occurred without changes in kinase protein expression, suggesting a long-lasting, post-translational modification of the enzyme. This is the first published report of a persistent, post-translational alteration of CaM kinase II activity in a model of epilepsy characterized by spontaneous recurrent seizure activity.

  9. ARSENICALS INHIBIT THIOREDOXIN REDUCTASE ACTIVITY IN CULTURED RAT HEPATOCYTES

    EPA Science Inventory

    ARSENICALS INHIBIT THIOREDOXIN REDUCTASE ACTIVITY IN CULTURED RAT HEPATOCYTES.

    S. Lin1, L. M. Del Razo1, M. Styblo1, C. Wang2, W. R. Cullen2, and D.J. Thomas3. 1Univ. North Carolina, Chapel Hill, NC; 2Univ. British Columbia, Vancouver, BC, Canada; 3National Health and En...

  10. Apple Polyphenol Phloretin Inhibits Colorectal Cancer Cell Growth via Inhibition of the Type 2 Glucose Transporter and Activation of p53-Mediated Signaling.

    PubMed

    Lin, Sheng-Tsai; Tu, Shih-Hsin; Yang, Po-Sheng; Hsu, Sung-Po; Lee, Wei-Hwa; Ho, Chi-Tang; Wu, Chih-Hsiung; Lai, Yu-Hsin; Chen, Ming-Yao; Chen, Li-Ching

    2016-09-14

    Glucose transporters (GLUTs) are required for glucose uptake in malignant cells, and they can be used as molecular targets for cancer therapy. An RT-PCR analysis was performed to investigate the mRNA levels of 14 subtypes of GLUTs in human colorectal cancer (COLO 205 and HT-29) and normal (FHC) cells. RT-PCR (n = 27) was used to assess the differences in paired tissue samples (tumor vs normal) isolated from colorectal cancer patients. GLUT2 was detected in all tested cells. The average GLUT2 mRNA level in 12 of 27 (44.4%) cases was 2.4-fold higher in tumor compared to normal tissues (*, p = 0.027). Higher GLUT2 mRNA expression was preferentially detected in advanced-stage tumors (stage 0 vs 3 = 16.38-fold, 95% CI = 9.22-26.54-fold; *, p = 0.029). The apple polyphenol phloretin (Ph) and siRNA methods were used to inhibit GLUT2 protein expression. Ph (0-100 μM, for 24 h) induced COLO 205 cell growth cycle arrest in a p53-dependent manner, which was confirmed by pretreatment of the cells with a p53-specific dominant negative expression vector. Hepatocyte nuclear factor 6 (HNF6), which was previously reported to be a transcription factor that activates GLUT2 and p53, was also induced by Ph (0-100 μM, for 24 h). The antitumor effect of Ph (25 mg/kg or DMSO twice a week for 6 weeks) was demonstrated in vivo using BALB/c nude mice bearing COLO 205 tumor xenografts. In conclusion, targeting GLUT2 could potentially suppress colorectal tumor cell invasiveness.

  11. Preferential Allele Expression Analysis Identifies Shared Germline and Somatic Driver Genes in Advanced Ovarian Cancer

    PubMed Central

    Halabi, Najeeb M.; Martinez, Alejandra; Al-Farsi, Halema; Mery, Eliane; Puydenus, Laurence; Pujol, Pascal; Khalak, Hanif G.; McLurcan, Cameron; Ferron, Gwenael; Querleu, Denis; Al-Azwani, Iman; Al-Dous, Eman; Mohamoud, Yasmin A.; Malek, Joel A.; Rafii, Arash

    2016-01-01

    Identifying genes where a variant allele is preferentially expressed in tumors could lead to a better understanding of cancer biology and optimization of targeted therapy. However, tumor sample heterogeneity complicates standard approaches for detecting preferential allele expression. We therefore developed a novel approach combining genome and transcriptome sequencing data from the same sample that corrects for sample heterogeneity and identifies significant preferentially expressed alleles. We applied this analysis to epithelial ovarian cancer samples consisting of matched primary ovary and peritoneum and lymph node metastasis. We find that preferentially expressed variant alleles include germline and somatic variants, are shared at a relatively high frequency between patients, and are in gene networks known to be involved in cancer processes. Analysis at a patient level identifies patient-specific preferentially expressed alleles in genes that are targets for known drugs. Analysis at a site level identifies patterns of site specific preferential allele expression with similar pathways being impacted in the primary and metastasis sites. We conclude that genes with preferentially expressed variant alleles can act as cancer drivers and that targeting those genes could lead to new therapeutic strategies. PMID:26735499

  12. Influence of SLC6A3 and COMT Variation on Neural Activation During Response Inhibition

    PubMed Central

    Congdon, Eliza; Constable, R. Todd; Lesch, Klaus Peter; Canli, Turhan

    2009-01-01

    There is evidence concerning the neural and genetic correlates of inhibitory control, but there have been limited attempts to combine this information. This study tested the hypothesis that two dopaminergic polymorphisms, SLC6A3 and COMT, influence neural activation during response inhibition. Healthy adults were genotyped for these polymorphisms and performed a measure of response inhibition while undergoing functional magnetic resonance imaging (fMRI). Results support the role of key frontostriatal regions underlying response inhibition. Furthermore, results support a significant influence of SLC6A3 and COMT variants on neural activity during inhibition, with greater activation during inhibition in carriers of the SLC6A3 9-allele or the COMT met-allele as compared to carriers of the SLC6A3 10/10 genotype or the COMT val/val genotype. These results add to a growing literature suggesting that inhibitory control is sensitive to variation in dopamine function, and suggest that this variation may be detectable at the level of individuals’ genotypes. PMID:19482231

  13. Active inhibition of herpes simplex virus type 1-induced cell fusion

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bzik, D.J.; Person, S.; Read, G.S.

    1982-01-01

    Previous studies have demonstrated that syn mutant-infected cells fuse less well with nonsyncytial virus-infected cells than with uninfected cells, a phenomenon defined as function inhibition. The present study characterizes the kinetics as well as the requirements for expression of fusion inhibition. Initially, the capacity of sparse syn mutant-infected cells to fuse with uninfected surrounding cells was determined throughout infection. Of seven syn mutants examined, including representatives with alterations in two different viral genes that affect cell fusion, all showed an increase in fusion capacity up to 12 hr after infection and a decrease at later times. Fusion inhibition was examinedmore » in experiments employing sparse syn20-infected cells which had been incubated to a maximum fusion capacity; it was shown that surrounding cells infected with KOS, the parent of syn20, began to inhibit fusion by the syn20-infected cells at about 4 hr after infection, and that the maximum ability to inhibit fusion was attained at about 6 hr after infection. The metabolic blocking agents actinomycin D (RNA), cycloheximide (protein), 2-deoxyglucose, and tunicamycin (glycoslyation of glycoproteins) all showed the ability to inhibit the expression of fusion inhibition by KOS-infected cells if added shortly after infection. It is concluded that fusion inhibition is an active process that requires the synthesis of RNA, proteins, and glycoproteins. 17 references, 3 figures, 2 tables.« less

  14. TES inhibits colorectal cancer progression through activation of p38

    PubMed Central

    Gao, Lu; Wang, Lixia; Niu, Yanfeng; Liu, Hongli; Wang, Zheng; Wang, Lin; Wang, Guobin; Wang, Jiliang

    2016-01-01

    The human TESTIN (TES) gene has been identified as a candidate tumor suppressor based on its location at a common fragile site – a region where loss of heterozygosity has been detected in numerous types of tumors. To investigate its role in colorectal cancer (CRC), we examined TES protein levels in CRC tissue samples and cell lines. We observed that TES was markedly reduced in both CRC tissue and cell lines. Additionally, overexpression of TES significantly inhibited cell proliferation, migration, and invasion, while increasing cell apoptosis in colon cancer cells. By contrast, shRNA-mediated TES knockdown elicited the opposite effects. TES inhibited the progression of CRC by up-regulating pro-apoptotic proteins, down-regulating anti-apoptotic proteins, and simultaneously activating p38 mitogen-activated protein kinase (MAPK) signaling pathways. Collectively, these data indicate that TES functions as a necessary suppressor of CRC progression by activating p38-MAPK signaling pathways. This suggests that TES may have a potential application in CRC diagnosis and targeted gene therapy. PMID:27323777

  15. Identification of a Phosphodiesterase-Inhibiting Fraction from Roasted Coffee (Coffea arabica) through Activity-Guided Fractionation.

    PubMed

    Röhrig, Teresa; Liesenfeld, David; Richling, Elke

    2017-05-17

    Recent reports that coffee can significantly inhibit cAMP phosphodiesterases (PDEs) in vitro, as well as in vivo, have described another beneficial effect of coffee consumption. However, the PDE-inhibiting substances remain mostly unknown. We chose activity-guided fractionation and an in vitro test system to identify the coffee components that are responsible for PDE inhibition. This approach indicated that a fraction of melanoidins reveals strong PDE-inhibiting potential (IC 50 = 130 ± 42 μg/mL). These melanoidins were characterized as water-soluble, low-molecular weight melanoidins (<3 kDa) with a nitrogen content of 4.2% and a carbohydrate content lower than those of other melanoidins. Fractions containing known PDE inhibitors such as chlorogenic acids, alkylpyrazines, or trigonelline as well as N-caffeoyl-tryptophan and N-p-coumaroyl-tryptophan did not exert PDE-inhibiting activity. We also observed that the known PDE inhibitor caffeine does not contribute to the PDE-inhibiting effects of coffee.

  16. Antibacterial, antioxidant and tyrosinase-inhibition activities of pomegranate fruit peel methanolic extract

    PubMed Central

    2012-01-01

    Background This study evaluated, using in vitro assays, the antibacterial, antioxidant, and tyrosinase-inhibition activities of methanolic extracts from peels of seven commercially grown pomegranate cultivars. Methods Antibacterial activity was tested on Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Klebsiella pneumonia) using a microdilution method. Several potential antioxidant activities, including radical-scavenging ability (RSA), ferrous ion chelating (FIC) and ferric ion reducing antioxidant power (FRAP), were evaluated. Tyrosinase enzyme inhibition was investigated against monophenolase (tyrosine) and diphenolase (DOPA), with arbutin and kojic acid as positive controls. Furthermore, phenolic contents including total flavonoid content (TFC), gallotannin content (GTC) and total anthocyanin content (TAC) were determined using colourimetric methods. HPLC-ESI/MSn analysis of phenolic composition of methanolic extracts was also performed. Results Methanolic peel extracts showed strong broad-spectrum activity against Gram-positive and Gram-negative bacteria, with the minimum inhibitory concentrations (MIC) ranging from 0.2 to 0.78 mg/ml. At the highest concentration tested (1000 μg/ml), radical scavenging activities were significantly higher in Arakta (83.54%), Ganesh (83.56%), and Ruby (83.34%) cultivars (P< 0.05). Dose dependent FIC and FRAP activities were exhibited by all the peel extracts. All extracts also exhibited high inhibition (>50%) against monophenolase and diphenolase activities at the highest screening concentration. The most active peel extract was the Bhagwa cultivar against monophenolase and the Arakta cultivar against diphenolase with IC50 values of 3.66 μg/ml and 15.88 μg/ml, respectively. High amounts of phenolic compounds were found in peel extracts with the highest and lowest total phenolic contents of 295.5 (Ganesh) and 179.3 mg/g dry extract (Molla de Elche), respectively

  17. Lipid-induced NOX2 activation inhibits autophagic flux by impairing lysosomal enzyme activity[S

    PubMed Central

    Jaishy, Bharat; Zhang, Quanjiang; Chung, Heaseung S.; Riehle, Christian; Soto, Jamie; Jenkins, Stephen; Abel, Patrick; Cowart, L. Ashley; Van Eyk, Jennifer E.; Abel, E. Dale

    2015-01-01

    Autophagy is a catabolic process involved in maintaining energy and organelle homeostasis. The relationship between obesity and the regulation of autophagy is cell type specific. Despite adverse consequences of obesity on cardiac structure and function, the contribution of altered cardiac autophagy in response to fatty acid overload is incompletely understood. Here, we report the suppression of autophagosome clearance and the activation of NADPH oxidase (Nox)2 in both high fat-fed murine hearts and palmitate-treated H9C2 cardiomyocytes (CMs). Defective autophagosome clearance is secondary to superoxide-dependent impairment of lysosomal acidification and enzyme activity in palmitate-treated CMs. Inhibition of Nox2 prevented superoxide overproduction, restored lysosome acidification and enzyme activity, and reduced autophagosome accumulation in palmitate-treated CMs. Palmitate-induced Nox2 activation was dependent on the activation of classical protein kinase Cs (PKCs), specifically PKCβII. These findings reveal a novel mechanism linking lipotoxicity with a PKCβ-Nox2-mediated impairment in pH-dependent lysosomal enzyme activity that diminishes autophagic turnover in CMs. PMID:25529920

  18. Relations between macropore network characteristics and the degree of preferential solute transport

    NASA Astrophysics Data System (ADS)

    Larsbo, M.; Koestel, J.; Jarvis, N.

    2014-12-01

    The characteristics of the soil macropore network determine the potential for fast transport of agrochemicals and contaminants through the soil. The objective of this study was to examine the relationships between macropore network characteristics, hydraulic properties and state variables and measures of preferential transport. Experiments were carried out under near-saturated conditions on undisturbed columns sampled from four agricultural topsoils of contrasting texture and structure. Macropore network characteristics were computed from 3-D X-ray tomography images of the soil pore system. Non-reactive solute transport experiments were carried out at five steady-state water flow rates from 2 to 12 mm h-1. The degree of preferential transport was evaluated by the normalised 5% solute arrival time and the apparent dispersivity calculated from the resulting breakthrough curves. Near-saturated hydraulic conductivities were measured on the same samples using a tension disc infiltrometer placed on top of the columns. Results showed that many of the macropore network characteristics were inter-correlated. For example, large macroporosities were associated with larger specific macropore surface areas and better local connectivity of the macropore network. Generally, an increased flow rate resulted in earlier solute breakthrough and a shifting of the arrival of peak concentration towards smaller drained volumes. Columns with smaller macroporosities, poorer local connectivity of the macropore network and smaller near-saturated hydraulic conductivities exhibited a greater degree of preferential transport. This can be explained by the fact that, with only two exceptions, global (i.e. sample scale) continuity of the macropore network was still preserved at low macroporosities. Thus, for any given flow rate, pores of larger diameter were actively conducting solute in soils of smaller near-saturated hydraulic conductivity. This was associated with larger local transport

  19. Quantifying Preferential Flow and Seasonal Storage in an Unsaturated Fracture-Facial Domain

    NASA Astrophysics Data System (ADS)

    Nimmo, J. R.; Malek-Mohammadi, S.

    2012-12-01

    Preferential flow through deep unsaturated zones of fractured rock is hydrologically important to a variety of contaminant transport and water-resource issues. The unsaturated zone of the English Chalk Aquifer provides an important opportunity for a case study of unsaturated preferential flow in isolation from other flow modes. The chalk matrix has low hydraulic conductivity and stays saturated, owing to its fine uniform pores and the wet climate of the region. Therefore the substantial fluxes observed in the unsaturated chalk must be within fractures and interact minimally with matrix material. Price et al. [2000] showed that irregularities on fracture surfaces provide a significant storage capacity in the chalk unsaturated zone, likely accounting for volumes of water required to explain unexpected dry-season water-table stability during substantial continuing streamflow observed by Lewis et al. [1993] In this presentation we discuss and quantify the dynamics of replenishment and drainage of this unsaturated zone fracture-face storage domain using a modification of the source-responsive model of Nimmo [2010]. This model explains the processes in terms of two interacting flow regimes: a film or rivulet preferential flow regime on rough fracture faces, active on an individual-storm timescale, and a regime of adsorptive and surface-tension influences, resembling traditional diffuse formulations of unsaturated flow, effective mainly on a seasonal timescale. The modified model identifies hydraulic parameters for an unsaturated fracture-facial domain lining the fractures. Besides helping to quantify the unsaturated zone storage described by Price et al., these results highlight the importance of research on the topic of unsaturated-flow relations within a near-fracture-surface domain. This model can also facilitate understanding of mechanisms for reinitiation of preferential flow after temporary cessation, which is important in multi-year preferential flow through deep

  20. Berberine suppresses tumorigenicity and growth of nasopharyngeal carcinoma cells by inhibiting STAT3 activation induced by tumor associated fibroblasts.

    PubMed

    Tsang, Chi Man; Cheung, Yuk Chun; Lui, Vivian Wai-Yan; Yip, Yim Ling; Zhang, Guitao; Lin, Victor Weitao; Cheung, Kenneth Chat-Pan; Feng, Yibin; Tsao, Sai Wah

    2013-12-31

    Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activation, has also been documented. In this study, we have examined the effects of berberine on tumorigenicity and growth of nasopharyngeal carcinoma (NPC) cells and their relationship to STAT3 signaling using both in vivo and in vitro models. Berberine effectively inhibited the tumorigenicity and growth of an EBV-positive NPC cell line (C666-1) in athymic nude mice. Inhibition of tumorigenic growth of NPC cells in vivo was correlated with effective inhibition of STAT3 activation in NPC cells inside the tumor xenografts grown in nude mice. In vitro, berberine inhibited both constitutive and IL-6-induced STAT3 activation in NPC cells. Inhibition of STAT3 activation by berberine induced growth inhibition and apoptotic response in NPC cells. Tumor-associated fibroblasts were found to secret IL-6 and the conditioned medium harvested from the fibroblasts also induced STAT3 activation in NPC cells. Furthermore, STAT3 activation by conditioned medium of tumor-associated fibroblasts could be blocked by berberine or antibodies against IL-6 and IL-6R. Our observation that berberine effectively inhibited activation of STAT3 induced by tumor-associated fibroblasts suggests a role of berberine in modulating the effects of tumor stroma on the growth of NPC cells. The effective inhibition of STAT3 activation in NPC cells by berberine supports its potential use in the treatment of NPC.

  1. Berberine suppresses tumorigenicity and growth of nasopharyngeal carcinoma cells by inhibiting STAT3 activation induced by tumor associated fibroblasts

    PubMed Central

    2013-01-01

    Background Cortidis rhizoma (Huanglian) and its major therapeutic component, berberine, have drawn extensive attention in recent years for their anti-cancer properties. Growth inhibitory effects of berberine on multiple types of human cancer cells have been reported. Berberine inhibits invasion, induces cell cycle arrest and apoptosis in human cancer cells. The anti-inflammatory property of berberine, involving inhibition of Signal Transducer and Activator of Transcription 3 (STAT3) activation, has also been documented. Methods In this study, we have examined the effects of berberine on tumorigenicity and growth of nasopharyngeal carcinoma (NPC) cells and their relationship to STAT3 signaling using both in vivo and in vitro models. Results Berberine effectively inhibited the tumorigenicity and growth of an EBV-positive NPC cell line (C666-1) in athymic nude mice. Inhibition of tumorigenic growth of NPC cells in vivo was correlated with effective inhibition of STAT3 activation in NPC cells inside the tumor xenografts grown in nude mice. In vitro, berberine inhibited both constitutive and IL-6-induced STAT3 activation in NPC cells. Inhibition of STAT3 activation by berberine induced growth inhibition and apoptotic response in NPC cells. Tumor-associated fibroblasts were found to secret IL-6 and the conditioned medium harvested from the fibroblasts also induced STAT3 activation in NPC cells. Furthermore, STAT3 activation by conditioned medium of tumor-associated fibroblasts could be blocked by berberine or antibodies against IL-6 and IL-6R. Conclusions Our observation that berberine effectively inhibited activation of STAT3 induced by tumor-associated fibroblasts suggests a role of berberine in modulating the effects of tumor stroma on the growth of NPC cells. The effective inhibition of STAT3 activation in NPC cells by berberine supports its potential use in the treatment of NPC. PMID:24380387

  2. Preferential solvatation of human serum albumin in dimethylsulfoxide-H2O binary solution

    NASA Astrophysics Data System (ADS)

    Grigoryan, K. R.

    2009-12-01

    The preferential solvatation of human serum albumin (HSA) in dimethylsulfoxide (DMSO) aqueous solutions were studied using the densitometry method. It has been shown that at DMSO low concentrations HSA undergoes to preferential hydration, but at DMSO higher concentrations preferential binding of DMSO molecules to protein occurs. It has been estimated that DMSO exhibits stabilizing/destabilizing effect on HSA structure which is explained in terms of hydration/solvatation of protein, on the one hand, and the medium structure enhancement/disruption around the protein molecule, on the other hand.

  3. Environmentally persistent free radicals inhibit cytochrome P450 activity in rat liver microsomes

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Reed, James R., E-mail: rreed@lsuhsc.edu; The Stanley S. Scott Cancer Center, Louisiana State University Health Science Center, 533 Bolivar St., New Orleans, LA 70112; Cawley, George F.

    2014-06-01

    Combustion processes generate particulate matter that affects human health. When incineration fuels include components that are highly enriched in aromatic hydrocarbons (especially halogenated varieties) and redox-active metals, ultrafine particulate matter containing air-stable, environmentally persistent free radicals (EPFRs) is generated. The exposure to fine EPFRs (less than 2.5 μm in diameter) has been shown to negatively influence pulmonary and cardiovascular functions in living organisms. The goal of this study was to determine if these EPFRs have a direct effect on cytochrome P450 function. This was accomplished by direct addition of the EPFRs to rat liver microsomal preparations and measurement of severalmore » P450 activities using form-selective substrates. The EPFRs used in this study were formed by heating vapors from an organic compound (either monochlorophenol (MCP230) or 1,2-dichlorobenzene (DCB230)) and 5% copper oxide supported on silica (approximately 0.2 μm in diameter) to 230 °C under vacuum. Both types of EPFRs (but not silica, physisorbed silica, or silica impregnated with copper oxide) dramatically inhibited the activities of CYP1A, CYP2B, CYP2E1, CYP2D2 and CYP3A when incubated at concentrations less than 0.1 mg/ml with microsomes and NADPH. Interestingly, at the same concentrations, the EPFRs did not inhibit HO-1 activity or the reduction of cytochrome c by NADPH-cytochrome P450 reductase. CYP2D2-selective metabolism by rat liver microsomes was examined in more detail. The inhibition of CYP2D2-selective metabolism by both DCB230- and MCP230-EPFRs appeared to be largely noncompetitive and was attenuated in the presence of catalase suggesting that reactive oxygen species may be involved in the mechanism of inhibition. - Highlights: • Combustion of organic pollutants generates long-lived particulate radicals (EPFRs). • EPFRs inhibit metabolism by all cytochromes P450 tested in rat liver microsomes. • EPFR-mediated inhibition is

  4. Inhibition of angiogenesis by vitamin D-binding protein: characterization of anti-endothelial activity of DBP-maf.

    PubMed

    Kalkunte, Satyan; Brard, Laurent; Granai, Cornelius O; Swamy, Narasimha

    2005-01-01

    Angiogenesis is a complex process involving coordinated steps of endothelial cell activation, proliferation, migration, tube formation and capillary sprouting with participation of intracellular signaling pathways. Regulation of angiogenesis carries tremendous potential for cancer therapy. Our earlier studies showed that vitamin D-binding protein-macrophage activating factor (DBP-maf) acts as a potent anti-angiogenic factor and inhibits tumor growth in vivo. The goal of this investigation was to understand the effect of DBP-maf on human endothelial cell (HEC) and the mechanism of angiogenesis inhibition. DBP-maf inhibited human endothelial cell (HEC) proliferation by inhibiting DNA synthesis (IC(50) = 7.8 +/- 0.15 microg/ml). DBP-maf significantly induced S- and G0/G1-phase arrest in HEC in 72 h. DBP-maf potently blocked VEGF-induced migration, tube-formation of HEC in a dose dependent manner. In addition, DBP-maf inhibited growth factor-induced microvessel sprouting in rat aortic ring assay. Moreover, DBP-maf inhibited VEGF signaling by decreasing VEGF-mediated phosphorylation of VEGFR-2 and ERK1/2, a downstream target of VEGF signaling cascade. However, Akt activation was not affected. These studies collectively demonstrate that DBP-maf inhibits angiogenesis by blocking critical steps such as HEC proliferation, migration, tube formation and microvessel sprouting. DBP-maf exerts its effect by inhibiting VEGR-2 and ERK1/2 signaling cascades. Understanding the cellular and molecular mechanisms of anti-endothelial activity of DBP-maf will allow us to develop it as an angiogenesis targeting novel drug for tumor therapy.

  5. Berberine-induced AMPK activation inhibits the metastatic potential of melanoma cells via reduction of ERK activity and COX-2 protein expression.

    PubMed

    Kim, Hak-Su; Kim, Myung-Jin; Kim, Eun Ju; Yang, Young; Lee, Myeong-Sok; Lim, Jong-Seok

    2012-02-01

    Berberine is clinically important natural isoquinoline alkaloid that affects various biological functions, such as cell proliferation, migration and survival. The activation of AMP-activated protein kinase (AMPK) regulates tumor cell migration. However, the specific role of AMPK on the metastatic potential of cancer cells remains largely unknown. The present study investigated whether berberine induces AMPK activation and whether this induction directly affects mouse melanoma cell migration, adhesion and invasion. Berberine strongly increased AMPK phosphorylation via reactive oxygen species (ROS) production. 5-Aminoimidazole-4-carboxamide-1-β-D-ribofuranoside (AICAR), a well-known AMPK activator, also inhibited tumor cell adhesion and invasion and reduced the expression of epithelial to mesenchymal transition (EMT)-related genes. Knockdown of AMPKα subunits using siRNAs significantly abated the berberine-induced inhibition of tumor cell invasion. Furthermore, berberine inhibited the metastatic potential of melanoma cells through a decrease in ERK activity and protein levels of cyclooxygenase-2 (COX-2) by a berberine-induced AMPK activation. These data were confirmed using specific MEK inhibitor, PD98059, and a COX-2 inhibitor, celecoxib. Berberine- and AICAR-treated groups demonstrated significantly decreased lung metastases in the pulmonary metastasis model in vivo. Treatment with berberine also decreased the metastatic potential of A375 human melanoma cells. Collectively, our results suggest that berberine-induced AMPK activation inhibits the metastatic potential of tumor cells through a reduction in the activity of the ERK signaling pathway and COX-2 protein levels. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Does trans‐spinal and local DC polarization affect presynaptic inhibition and post‐activation depression?

    PubMed Central

    Kaczmarek, D.; Ristikankare, J.

    2017-01-01

    Key points Trans‐spinal polarization was recently introduced as a means to improve deficient spinal functions. However, only a few attempts have been made to examine the mechanisms underlying DC actions. We have now examined the effects of DC on two spinal modulatory systems, presynaptic inhibition and post‐activation depression, considering whether they might weaken exaggerated spinal reflexes and enhance excessively weakened ones.Direct current effects were evoked by using local intraspinal DC application (0.3–0.4 μA) in deeply anaesthetized rats and were compared with the effects of trans‐spinal polarization (0.8–1.0 mA).Effects of local intraspinal DC were found to be polarity dependent, as locally applied cathodal polarization enhanced presynaptic inhibition and post‐activation depression, whereas anodal polarization weakened them. In contrast, both cathodal and anodal trans‐spinal polarization facilitated them.The results suggest some common DC‐sensitive mechanisms of presynaptic inhibition and post‐activation depression, because both were facilitated or depressed by DC in parallel. Abstract Direct current (DC) polarization has been demonstrated to alleviate the effects of various deficits in the operation of the central nervous system. However, the effects of trans‐spinal DC stimulation (tsDCS) have been investigated less extensively than the effects of transcranial DC stimulation, and their cellular mechanisms have not been elucidated. The main objectives of this study were, therefore, to extend our previous analysis of DC effects on the excitability of primary afferents and synaptic transmission by examining the effects of DC on two spinal modulatory feedback systems, presynaptic inhibition and post‐activation depression, in an anaesthetized rat preparation. Other objectives were to compare the effects of locally and trans‐spinally applied DC (locDC and tsDCS). Local polarization at the sites of terminal branching of afferent

  7. S -Nitrosylation inhibits the kinase activity of tomato phosphoinositide-dependent kinase 1 (PDK1)

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, Jian-Zhong; Duan, Jicheng; Ni, Min

    It is well known that the reactive oxygen species NO can trigger cell death in plants and other organisms, but the underlying molecular mechanisms are not well understood. Here we provide evidence that NO may trigger cell death in tomato (Solanum lycopersicum) by inhibiting the activity of phosphoinositide-dependent kinase 1 (SlPDK1), a conserved negative regulator of cell death in yeasts, mammals, and plants, via S-nitrosylation. Biotin-switch assays indicated that SlPDK1 is a target of S-nitrosylation. Moreover, the kinase activity of SlPDK1 was inhibited by S-nitrosoglutathione in a concentration-dependent manner, indicating that SlPDK1 activity is abrogated by S-nitrosylation. The S-nitrosoglutathione–induced inhibitionmore » was reversible in the presence of a reducing agent but additively enhanced by hydrogen peroxide (H 2O 2). Our LC-MS/MS analyses further indicated that SlPDK1 is primarily S-nitrosylated on a cysteine residue at position 128 (Cys 128), and substitution of Cys 128 with serine completely abolished SlPDK1 kinase activity, suggesting that S-nitrosylation of Cys 128 is responsible for SlPDK1 inhibition. In summary, our results establish a potential link between NO-triggered cell death and inhibition of the kinase activity of tomato PDK1.« less

  8. S -Nitrosylation inhibits the kinase activity of tomato phosphoinositide-dependent kinase 1 (PDK1)

    DOE PAGES

    Liu, Jian-Zhong; Duan, Jicheng; Ni, Min; ...

    2017-09-29

    It is well known that the reactive oxygen species NO can trigger cell death in plants and other organisms, but the underlying molecular mechanisms are not well understood. Here we provide evidence that NO may trigger cell death in tomato (Solanum lycopersicum) by inhibiting the activity of phosphoinositide-dependent kinase 1 (SlPDK1), a conserved negative regulator of cell death in yeasts, mammals, and plants, via S-nitrosylation. Biotin-switch assays indicated that SlPDK1 is a target of S-nitrosylation. Moreover, the kinase activity of SlPDK1 was inhibited by S-nitrosoglutathione in a concentration-dependent manner, indicating that SlPDK1 activity is abrogated by S-nitrosylation. The S-nitrosoglutathione–induced inhibitionmore » was reversible in the presence of a reducing agent but additively enhanced by hydrogen peroxide (H 2O 2). Our LC-MS/MS analyses further indicated that SlPDK1 is primarily S-nitrosylated on a cysteine residue at position 128 (Cys 128), and substitution of Cys 128 with serine completely abolished SlPDK1 kinase activity, suggesting that S-nitrosylation of Cys 128 is responsible for SlPDK1 inhibition. In summary, our results establish a potential link between NO-triggered cell death and inhibition of the kinase activity of tomato PDK1.« less

  9. Ligand Activation of Peroxisome Proliferator-Activated Receptor-β/δ Inhibits Cell Proliferation in Human HaCaT KeratinocytesS

    PubMed Central

    Borland, Michael G.; Foreman, Jennifer E.; Girroir, Elizabeth E.; Zolfaghari, Reza; Sharma, Arun K.; Amin, Shantu; Gonzalez, Frank J.; Ross, A. Catharine; Peters, Jeffrey M.

    2009-01-01

    Although there is strong evidence that ligand activation of peroxisome proliferator-activated receptor (PPAR)-β/δ induces terminal differentiation and attenuates cell growth, some studies suggest that PPARβ/δ actually enhances cell proliferation. For example, it was suggested recently that retinoic acid (RA) is a ligand for PPARβ/δ and potentiates cell proliferation by activating PPARβ/δ. The present study examined the effect of ligand activation of PPARβ/δ on cell proliferation, cell cycle kinetics, and target gene expression in human HaCaT keratinocytes using two highly specific PPARβ/δ ligands [4-[[[2-[3-fluoro-4-(trifluoromethyl)phenyl]-4-methyl-5-thiazolyl]methyl]thio]-2-methylphenoxy acetic acid (GW0742) and 2-methyl-4-((4-methyl-2-(4-trifluoromethylphenyl)-1,3-thiazol-5-yl)-methylsulfanyl)phenoxy-acetic acid (GW501516)] and RA. Both PPARβ/δ ligands and RA inhibited cell proliferation of HaCaT keratinocytes. GW0742 and GW501516 increased expression of known PPARβ/δ target genes, whereas RA did not; RA increased the expression of known retinoic acid receptor/retinoid X receptor target genes, whereas GW0742 did not affect these genes. GW0742, GW501516, and RA did not modulate the expression of 3-phosphoinositide-dependent protein kinase or alter protein kinase B phosphorylation. GW0742 and RA increased annexin V staining as quantitatively determined by flow cytometry. The effects of GW0742 and RA were also examined in wild-type and PPARβ/δ-null primary mouse keratinocytes to determine the specific role of PPARβ/δ in modulating cell growth. Although inhibition of keratinocyte proliferation by GW0742 was PPARβ/δ-dependent, inhibition of cell proliferation by RA occurred in both genotypes. Results from these studies demonstrate that ligand activation of PPARβ/δ inhibits keratinocyte proliferation through PPARβ/δ-dependent mechanisms. In contrast, the observed inhibition of cell proliferation in mouse and human keratinocytes by RA is

  10. Revisiting the mechanistic basis of the French Paradox: Red wine inhibits the activity of protein disulfide isomerase in vitro.

    PubMed

    Galinski, Christine N; Zwicker, Jeffrey I; Kennedy, Daniel R

    2016-01-01

    Although epidemiologic evidence points to cardioprotective activity of red wine, the mechanistic basis for antithrombotic activity has not been established. Quercetin and related flavonoids are present in high concentrations in red but not white wine. Quercetin-glycosides were recently shown to prevent thrombosis in animal models through the inhibition of extracellular protein disulfide isomerase (PDI). We evaluated whether red or white wine inhibited PDI activity in vitro. Quercetin levels in red and white wines were measured by HPLC analysis. Inhibition of PDI activity by red and white wines was assessed by an insulin reduction turbidity assay at various concentrations of wine. PDI inhibition was confirmed using a reduced peptide that contained a disulfide containing peptide as a substrate. The inhibition of PDI related thiol isomerases ERp5 and ERp57 was also assessed. We observed a dose-dependent decrease of PDI activity for a variety of red but not white wines. Red wine diluted to 3% final concentration resulted in over 80% inhibition of PDI activity by insulin reductase assay for all varieties tested. This inhibition was also observed in the peptide based assay. Red grape juice yielded similar results but ethanol alone did not affect PDI activity. Interestingly, red wine also inhibited the PDI related thiol isomerases ERp5 and ERp57, albeit to a lesser degree than PDI. PDI activity is inhibited by red wine and grape juice, identifying a potentially novel mechanism underlying the cardiovascular benefits attributed to wine consumption. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Revisiting the mechanistic basis of the French Paradox: red wine inhibits the activity of protein disulfide isomerase in vitro

    PubMed Central

    Galinski, Christine N.; Zwicker, Jeffrey I.; Kennedy, Daniel R.

    2015-01-01

    Introduction Although epidemiologic evidence points to cardioprotective activity of red wine, the mechanistic basis for antithrombotic activity has not been established. Quercetin and related flavonoids are present in high concentrations in red but not white wine. Quercetin-glycosides were recently shown to prevent thrombosis in animal models through the inhibition of extracellular protein disulfide isomerase (PDI). We evaluated whether red or white wine inhibited PDI activity in vitro. Methods Quercetin levels in red and white wines were measured by HPLC analysis. Inhibition of PDI activity by red and white wines was assessed by an insulin reduction turbidity assay at various concentrations of wine. PDI inhibition was confirmed using a reduced peptide that contained a disulfide containing peptide as a substrate. The inhibition of PDI related thiol isomerases ERp5 and ERp57 was also assessed. Results We observed a dose-dependent decrease of PDI activity for a variety of red but not white wines. Red wine diluted to 3% final concentration resulted in over 80% inhibition of PDI activity by insulin reductase assay for all varieties tested. This inhibition was also observed in the peptide based assay. Red grape juice yielded similar results but ethanol alone did not affect PDI activity. Interestingly, red wine also inhibited the PDI related thiol isomerases ERp5 and ERp57, albeit to a lesser degree than PDI. Conclusions PDI activity is inhibited by red wine and grape juice, identifying a potentially novel mechanism underlying the cardiovascular benefits attributed to wine consumption. PMID:26585763

  12. Osthole inhibits histamine-dependent itch via modulating TRPV1 activity.

    PubMed

    Yang, Niu-Niu; Shi, Hao; Yu, Guang; Wang, Chang-Ming; Zhu, Chan; Yang, Yan; Yuan, Xiao-Lin; Tang, Min; Wang, Zhong-Li; Gegen, Tana; He, Qian; Tang, Kehua; Lan, Lei; Wu, Guan-Yi; Tang, Zong-Xiang

    2016-05-10

    Osthole, an active coumarin isolated from Cnidium monnieri (L.) Cusson, has long been used in China as an antipruritic herbal medicine; however, the antipruitic mechanism of osthole is unknown. We studied the molecular mechanism of osthole in histamine-dependent itch by behavioral test, Ca(2+) imaging, and electrophysiological experiments. First, osthole clearly remitted the scratching behaviors of mice induced with histamine, HTMT, and VUF8430. Second, in cultured dorsal root ganglion (DRG) neurons, osthole showed a dose-dependent inhibitory effect to histamine. On the same neurons, osthole also decreased the response to capsaicin and histamine. In further tests, the capsaicin-induced inward currents were inhibited by osthole. These results revealed that osthole inhibited histamine-dependent itch by modulating TRPV1 activity. This study will be helpful in understanding how osthole exerts anti-pruritus effects and suggests that osthole may be a useful treatment medicine for histamine-dependent itch.

  13. Osthole inhibits histamine-dependent itch via modulating TRPV1 activity

    PubMed Central

    Yang, Niu-Niu; Shi, Hao; Yu, Guang; Wang, Chang-Ming; Zhu, Chan; Yang, Yan; Yuan, Xiao-Lin; Tang, Min; Wang, Zhong-li; Gegen, Tana; He, Qian; Tang, Kehua; Lan, Lei; Wu, Guan-Yi; Tang, Zong-Xiang

    2016-01-01

    Osthole, an active coumarin isolated from Cnidium monnieri (L.) Cusson, has long been used in China as an antipruritic herbal medicine; however, the antipruitic mechanism of osthole is unknown. We studied the molecular mechanism of osthole in histamine-dependent itch by behavioral test, Ca2+ imaging, and electrophysiological experiments. First, osthole clearly remitted the scratching behaviors of mice induced with histamine, HTMT, and VUF8430. Second, in cultured dorsal root ganglion (DRG) neurons, osthole showed a dose-dependent inhibitory effect to histamine. On the same neurons, osthole also decreased the response to capsaicin and histamine. In further tests, the capsaicin-induced inward currents were inhibited by osthole. These results revealed that osthole inhibited histamine-dependent itch by modulating TRPV1 activity. This study will be helpful in understanding how osthole exerts anti-pruritus effects and suggests that osthole may be a useful treatment medicine for histamine-dependent itch. PMID:27160770

  14. Brain activation for response inhibition under gaming cue distraction in internet gaming disorder.

    PubMed

    Liu, Gin-Chung; Yen, Ju-Yu; Chen, Chiao-Yun; Yen, Cheng-Fang; Chen, Cheng-Sheng; Lin, Wei-Chen; Ko, Chih-Hung

    2014-01-01

    We evaluated neural substrates related to the loss of control in college students with internet gaming disorder (IGD). We hypothesized that deficit in response inhibition under gaming cue distraction was the possible mechanism for the loss of control internet use. Eleven cases of IGD and 11 controls performed Go/NoGo tasks with/without gaming distraction in the functional magnetic resonance imaging scanner. When the gaming picture was shown as background while individuals were performing Go/NoGo tasks, the IGD group committed more commission errors. The control group increased their brain activations more over the right dorsolateral prefrontal cortex (DLPFC) and superior parietal lobe under gaming cue distraction in comparison with the IGD group. Furthermore, brain activation of the right DLPFC and superior parietal lobe were negatively associated with performance of response inhibition among the IGD group. The results suggest that the function of response inhibition was impaired under gaming distraction among the IGD group, and individuals with IGD could not activate right DLPFC and superior parietal lobe to keep cognitive control and attention allocation for response inhibition under gaming cue distraction. This mechanism should be addressed in any intervention for IGD. Copyright © 2013. Published by Elsevier B.V.

  15. Active and Passive 3D Vector Radiative Transfer with Preferentially-Aligned Ice Particles

    NASA Astrophysics Data System (ADS)

    Adams, I. S.; Munchak, S. J.; Pelissier, C.; Kuo, K. S.; Heymsfield, G. M.

    2017-12-01

    To support the observation of clouds and precipitation using combinations of radars and radiometers, a forward model capable of representing diverse sensing geometries for active and passive instruments is necessary for correctly interpreting and consistently combining multi-sensor measurements from ground-based, airborne, and spaceborne platforms. As such, the Atmospheric Radiative Transfer Simulator (ARTS) uses Monte Carlo integration to produce radar reflectivities and radiometric brightness temperatures for three-dimensional cloud and precipitation input fields. This radiative transfer framework is capable of efficiently sampling Gaussian antenna beams and fully accounting for multiple scattering. By relying on common ray-tracing tools, gaseous absorption models, and scattering properties, the model reproduces accurate and consistent radar and radiometer observables. While such a framework is an important component for simulating remote sensing observables, the key driver for self-consistent radiative transfer calculations of clouds and precipitation is scattering data. Research over the past decade has demonstrated that spheroidal models of frozen hydrometeors cannot accurately reproduce all necessary scattering properties at all desired frequencies. The discrete dipole approximation offers flexibility in calculating scattering for arbitrary particle geometries, but at great computational expense. When considering scattering for certain pristine ice particles, the Extended Boundary Condition Method, or T-Matrix, is much more computationally efficient; however, convergence for T-Matrix calculations fails at large size parameters and high aspect ratios. To address these deficiencies, we implemented the Invariant Imbedding T-Matrix Method (IITM). A brief overview of ARTS and IITM will be given, including details for handling preferentially-aligned hydrometeors. Examples highlighting the performance of the model for simulating space-based and airborne measurements

  16. Quiescent Fibroblasts Exhibit High Metabolic Activity

    PubMed Central

    Lemons, Johanna M. S.; Feng, Xiao-Jiang; Bennett, Bryson D.; Legesse-Miller, Aster; Johnson, Elizabeth L.; Raitman, Irene; Pollina, Elizabeth A.; Rabitz, Herschel A.; Rabinowitz, Joshua D.; Coller, Hilary A.

    2010-01-01

    Many cells in mammals exist in the state of quiescence, which is characterized by reversible exit from the cell cycle. Quiescent cells are widely reported to exhibit reduced size, nucleotide synthesis, and metabolic activity. Much lower glycolytic rates have been reported in quiescent compared with proliferating lymphocytes. In contrast, we show here that primary human fibroblasts continue to exhibit high metabolic rates when induced into quiescence via contact inhibition. By monitoring isotope labeling through metabolic pathways and quantitatively identifying fluxes from the data, we show that contact-inhibited fibroblasts utilize glucose in all branches of central carbon metabolism at rates similar to those of proliferating cells, with greater overflow flux from the pentose phosphate pathway back to glycolysis. Inhibition of the pentose phosphate pathway resulted in apoptosis preferentially in quiescent fibroblasts. By feeding the cells labeled glutamine, we also detected a “backwards” flux in the tricarboxylic acid cycle from α-ketoglutarate to citrate that was enhanced in contact-inhibited fibroblasts; this flux likely contributes to shuttling of NADPH from the mitochondrion to cytosol for redox defense or fatty acid synthesis. The high metabolic activity of the fibroblasts was directed in part toward breakdown and resynthesis of protein and lipid, and in part toward excretion of extracellular matrix proteins. Thus, reduced metabolic activity is not a hallmark of the quiescent state. Quiescent fibroblasts, relieved of the biosynthetic requirements associated with generating progeny, direct their metabolic activity to preservation of self integrity and alternative functions beneficial to the organism as a whole. PMID:21049082

  17. Tob1 induces apoptosis and inhibits proliferation, migration and invasion of gastric cancer cells by activating Smad4 and inhibiting β‑catenin signaling.

    PubMed

    Kundu, Juthika; Wahab, S M Riajul; Kundu, Joydeb Kumar; Choi, Yoon-La; Erkin, Ozgur Cem; Lee, Hun Seok; Park, Sang Gyu; Shin, Young Kee

    2012-09-01

    Transducer of ErbB-2.1 (Tob1), a tumor suppressor protein, is inactivated in a variety of cancers including stomach cancer. However, the role of Tob1 in gastric carcinogenesis remains elusive. The present study aimed to investigate whether Tob1 could inhibit gastric cancer progression in vitro, and to elucidate its underlying molecular mechanisms. We found differential expression of Tob1 in human gastric cancer (MKN28, AGS and MKN1) cells. The overexpression of Tob1 induced apoptosis in MKN28 and AGS cells, which was associated with sub-G1 arrest, activation of caspase-3, induction of Bax, inhibition of Bcl-2 and cleavage of poly (ADP-ribose) polymerase (PARP). In addition, Tob1 inhibited proliferation, migration and invasion, which were reversed in MKN1 and AGS cells transfected with Tob1 siRNA. Overexpression of Tob1 in MKN28 and AGS cells induced the expression of Smad4, leading to the increased expression and the promoter activity of p15, which was diminished by silencing of Tob1 using specific siRNA. Tob1 decreased the phosphorylation of Akt and glycogen synthase kinase-3β (GSK3β) in MKN28 and AGS cells, resulting in the reduced protein expression and the transcriptional activity of β‑catenin, which in turn decreased the expression of cyclin D1, cyclin-dependent kinase-4 (CDK4), urokinase plasminogen activator receptor (uPAR) and peroxisome proliferator and activator receptor-δ (PPARδ). Conversely, silencing of Tob1 induced the phosphorylation of Akt and GSK-3β, and increased the expression of β‑catenin and its target genes. Collectively, our study demonstrates that the overexpression of Tob1 inhibits gastric cancer progression by activating Smad4- and inhibiting β‑catenin-mediated signaling pathways.

  18. A New Small-Molecule Antagonist Inhibits Graves' Disease Antibody Activation of the TSH Receptor

    PubMed Central

    Eliseeva, Elena; McCoy, Joshua G.; Napolitano, Giorgio; Giuliani, Cesidio; Monaco, Fabrizio; Huang, Wenwei; Gershengorn, Marvin C.

    2011-01-01

    Context: Graves' disease (GD) is caused by persistent, unregulated stimulation of thyrocytes by thyroid-stimulating antibodies (TSAbs) that activate the TSH receptor (TSHR). We previously reported the first small-molecule antagonist of human TSHR and showed that it inhibited receptor signaling stimulated by sera from four patients with GD. Objective: Our objective was to develop a better TSHR antagonist and use it to determine whether inhibition of TSAb activation of TSHR is a general phenomenon. Design: We aimed to chemically modify a previously reported small-molecule TSHR ligand to develop a better antagonist and determine whether it inhibits TSHR signaling by 30 GD sera. TSHR signaling was measured in two in vitro systems: model HEK-EM293 cells stably overexpressing human TSHRs and primary cultures of human thyrocytes. TSHR signaling was measured as cAMP production and by effects on thyroid peroxidase mRNA. Results: We tested analogs of a previously reported small-molecule TSHR inverse agonist and selected the best NCGC00229600 for further study. In the model system, NCGC00229600 inhibited basal and TSH-stimulated cAMP production. NCGC00229600 inhibition of TSH signaling was competitive even though it did not compete for TSH binding; that is, NCGC00229600 is an allosteric inverse agonist. NCGC00229600 inhibited cAMP production by 39 ± 2.6% by all 30 GD sera tested. In primary cultures of human thyrocytes, NCGC00229600 inhibited TSHR-mediated basal and GD sera up-regulation of thyroperoxidase mRNA levels by 65 ± 2.0%. Conclusion: NCGC00229600, a small-molecule allosteric inverse agonist of TSHR, is a general antagonist of TSH receptor activation by TSAbs in GD patient sera. PMID:21123444

  19. A new small-molecule antagonist inhibits Graves' disease antibody activation of the TSH receptor.

    PubMed

    Neumann, Susanne; Eliseeva, Elena; McCoy, Joshua G; Napolitano, Giorgio; Giuliani, Cesidio; Monaco, Fabrizio; Huang, Wenwei; Gershengorn, Marvin C

    2011-02-01

    Graves' disease (GD) is caused by persistent, unregulated stimulation of thyrocytes by thyroid-stimulating antibodies (TSAbs) that activate the TSH receptor (TSHR). We previously reported the first small-molecule antagonist of human TSHR and showed that it inhibited receptor signaling stimulated by sera from four patients with GD. Our objective was to develop a better TSHR antagonist and use it to determine whether inhibition of TSAb activation of TSHR is a general phenomenon. We aimed to chemically modify a previously reported small-molecule TSHR ligand to develop a better antagonist and determine whether it inhibits TSHR signaling by 30 GD sera. TSHR signaling was measured in two in vitro systems: model HEK-EM293 cells stably overexpressing human TSHRs and primary cultures of human thyrocytes. TSHR signaling was measured as cAMP production and by effects on thyroid peroxidase mRNA. We tested analogs of a previously reported small-molecule TSHR inverse agonist and selected the best NCGC00229600 for further study. In the model system, NCGC00229600 inhibited basal and TSH-stimulated cAMP production. NCGC00229600 inhibition of TSH signaling was competitive even though it did not compete for TSH binding; that is, NCGC00229600 is an allosteric inverse agonist. NCGC00229600 inhibited cAMP production by 39 ± 2.6% by all 30 GD sera tested. In primary cultures of human thyrocytes, NCGC00229600 inhibited TSHR-mediated basal and GD sera up-regulation of thyroperoxidase mRNA levels by 65 ± 2.0%. NCGC00229600, a small-molecule allosteric inverse agonist of TSHR, is a general antagonist of TSH receptor activation by TSAbs in GD patient sera.

  20. Acetyl-CoA Carboxylase Inhibition Reverses NAFLD and Hepatic Insulin Resistance but Promotes Hypertriglyceridemia in Rodents.

    PubMed

    Goedeke, Leigh; Bates, Jamie; Vatner, Daniel F; Perry, Rachel J; Wang, Ting; Ramirez, Ricardo; Li, Li; Ellis, Matthew W; Zhang, Dongyan; Wong, Kari E; Beysen, Carine; Cline, Gary W; Ray, Adrian S; Shulman, Gerald I

    2018-05-23

    Pharmacologic inhibition of acetyl-CoA carboxylase (ACC) enzymes, ACC1 and ACC2, offers an attractive therapeutic strategy for non-alcoholic fatty liver disease (NAFLD) via simultaneous inhibition of fatty acid synthesis and stimulation of fatty acid oxidation. However, the effects of ACC inhibition on hepatic mitochondrial oxidation, anaplerosis, and ketogenesis in vivo are unknown. Here, we evaluated the impact of a novel liver-directed allosteric inhibitor of ACC1 and ACC2 (Compound 1) on these parameters, as well as glucose and lipid metabolism, in control and diet-induced rodent models of NAFLD. Oral administration of Compound 1 preferentially inhibited ACC enzymatic activity in the liver, reduced hepatic malonyl-CoA levels and enhanced hepatic ketogenesis by 50%. Furthermore, administration for 6 days to high-fructose fed rats resulted in a 20% reduction in hepatic de novo lipogenesis. Importantly, long-term treatment (21 days) significantly reduced high-fat sucrose diet (HFSD)-induced hepatic steatosis, PKCε activation and hepatic insulin resistance. ACCi treatment was associated with a significant increase in plasma triglycerides (∼30 to 130%, depending on length of fasting). ACCi-mediated hypertriglyceridemia could be attributed to a ∼15% increase in hepatic VLDL production and ∼20% reduction in triglyceride clearance by lipoprotein lipase (LPL) (P ≤ 0.05). At the molecular level, these changes were associated with increases in LXR/SREBP1 and decreases in PPARα target activation and could be reversed with fenofibrate co-treatment in a high-fat diet mouse model. Collectively, these studies warrant further investigation into the therapeutic utility of liver-directed ACC inhibition for the treatment of NAFLD and hepatic insulin resistance. This article is protected by copyright. All rights reserved. © 2018 by the American Association for the Study of Liver Diseases.

  1. The Diverse AAA+ Machines that Repair Inhibited Rubisco Active Sites

    PubMed Central

    Mueller-Cajar, Oliver

    2017-01-01

    Gaseous carbon dioxide enters the biosphere almost exclusively via the active site of the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco). This highly conserved catalyst has an almost universal propensity to non-productively interact with its substrate ribulose 1,5-bisphosphate, leading to the formation of dead-end inhibited complexes. In diverse autotrophic organisms this tendency has been counteracted by the recruitment of dedicated AAA+ (ATPases associated with various cellular activities) proteins that all use the energy of ATP hydrolysis to remodel inhibited Rubisco active sites leading to release of the inhibitor. Three evolutionarily distinct classes of these Rubisco activases (Rcas) have been discovered so far. Green and red-type Rca are mostly found in photosynthetic eukaryotes of the green and red plastid lineage respectively, whereas CbbQO is associated with chemoautotrophic bacteria. Ongoing mechanistic studies are elucidating how the various motors are utilizing both similar and contrasting strategies to ultimately perform their common function of cracking the inhibited Rubisco active site. The best studied mechanism utilized by red-type Rca appears to involve transient threading of the Rubisco large subunit C-terminal peptide, reminiscent of the action performed by Clp proteases. As well as providing a fascinating example of convergent molecular evolution, Rca proteins can be considered promising crop-improvement targets. Approaches aiming to replace Rubisco in plants with improved enzymes will need to ensure the presence of a compatible Rca protein. The thermolability of the Rca protein found in crop plants provides an opportunity to fortify photosynthesis against high temperature stress. Photosynthesis also appears to be limited by Rca when light conditions are fluctuating. Synthetic biology strategies aiming to enhance the autotrophic CO2 fixation machinery will need to take into consideration the requirement for Rubisco activases

  2. Eupatilin inhibits T-cell activation by modulation of intracellular calcium flux and NF-kappaB and NF-AT activity.

    PubMed

    Kim, Young-Dae; Choi, Suck-Chei; Oh, Tae-Young; Chun, Jang-Soo; Jun, Chang-Duk

    2009-09-01

    Eupatilin, one of the pharmacologically active ingredients of Artemisia princeps, exhibits a potent anti-ulcer activity, but its effects on T-cell immunity have not been investigated. Here, we show that eupatilin has a profound inhibitory effect on IL-2 production in Jurkat T cells as well as in human peripheral blood leukocytes. Eupatilin neither influenced clustering of CD3 and LFA-1 to the immunological synapse nor inhibited conjugate formation between T cells and B cells in the presence or absence of superantigen (SEE). Eupatilin also failed to inhibit T-cell receptor (TCR) internalization, thereby, suggesting that eupatilin does not interfere with TCR-mediated signals on the membrane proximal region. In unstimulated T cells, eupatilin significantly induced apoptotic cell death, as evidenced by an increased population of annexin V(+)/PI(+) cells and cleavage of caspase-3 and PARP. To our surprise, however, once cells were activated, eupatilin had little effect on apoptosis, and instead slightly protected cells from activation-induced cell death, suggesting that apoptosis also is not a mechanism for eupatilin-induced T-cell suppression. On the contrary, eupatilin dramatically inhibited I-kappaBalpha degradation and NF-AT dephosphorylation and, consequently, inhibited NF-kappaB and NF-AT promoter activities in PMA/A23187-stimulated T cells. Interestingly, intracellular calcium flux was significantly perturbed in cells pre-treated with eupatilin, suggesting that calcium-dependent cascades might be targets for eupatilin action. Collectively, our results provide evidence for dual regulatory functions of eupatilin: (1) a pro-apoptotic effect on resting T cells and (2) an immunosuppressive effect on activated T cells, presumably through modulation of Ca(2+) flux. (c) 2009 Wiley-Liss, Inc.

  3. Estimating Preferential Flow in Karstic Aquifers Using Statistical Mixed Models

    PubMed Central

    Anaya, Angel A.; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J.; Meeker, John D.; Alshawabkeh, Akram N.

    2013-01-01

    Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless-steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the statistical mixed models used in the study. PMID:23802921

  4. Identification of Homophily and Preferential Recruitment in Respondent-Driven Sampling.

    PubMed

    Crawford, Forrest W; Aronow, Peter M; Zeng, Li; Li, Jianghong

    2018-01-01

    Respondent-driven sampling (RDS) is a link-tracing procedure used in epidemiologic research on hidden or hard-to-reach populations in which subjects recruit others via their social networks. Estimates from RDS studies may have poor statistical properties due to statistical dependence in sampled subjects' traits. Two distinct mechanisms account for dependence in an RDS study: homophily, the tendency for individuals to share social ties with others exhibiting similar characteristics, and preferential recruitment, in which recruiters do not recruit uniformly at random from their network alters. The different effects of network homophily and preferential recruitment in RDS studies have been a source of confusion and controversy in methodological and empirical research in epidemiology. In this work, we gave formal definitions of homophily and preferential recruitment and showed that neither is identified in typical RDS studies. We derived nonparametric identification regions for homophily and preferential recruitment and showed that these parameters were not identified unless the network took a degenerate form. The results indicated that claims of homophily or recruitment bias measured from empirical RDS studies may not be credible. We applied our identification results to a study involving both a network census and RDS on a population of injection drug users in Hartford, Connecticut (2012-2013). © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  5. Attenuation of TNF-induced neutrophil adhesion by simvastatin is associated with the inhibition of Rho-GTPase activity, p50 activity and morphological changes.

    PubMed

    Antoniellis Silveira, Angélica Aparecida; Dominical, Venina Marcela; Morelli Vital, Daiana; Alves Ferreira, Wilson; Trindade Maranhão Costa, Fabio; Werneck, Claudio C; Ferreira Costa, Fernando; Conran, Nicola

    2018-05-01

    Neutrophil adhesion to the vasculature in response to potent inflammatory stimuli, such as TNF-α (TNF), can contribute to atheroprogression amongst other pathophysiological mechanisms. Previous studies have shown that simvastatin, a statin with known pleiotropic anti-inflammatory properties, can partially abrogate the effects of TNF-induced neutrophil adhesion, in association with the modulation of β 2 -integrin expression. We aimed to further characterize the effects of this statin on neutrophil and leukocyte adhesive mechanisms in vitro and in vivo. A microfluidic assay confirmed the ability of simvastatin to inhibit TNF-induced human neutrophil adhesion to fibronectin ligand under conditions of shear stress, while intravital imaging microscopy demonstrated an abrogation of leukocyte recruitment by simvastatin in the microvasculature of mice that had received a TNF stimulus. This inhibition of neutrophil adhesion was accompanied by the inhibition of TNF-induced RhoA activity in human neutrophils, and alterations in cell morphology and β 2 -integrin activity. Additionally, TNF augmented the activity of the p50 NFκB subunit in human neutrophils and TNF-induced neutrophil adhesion and β 2 -integrin activity could be abolished using pharmacological inhibitors of NFκB translocation, BAY11-7082 and SC514. Accordingly, the TNF-induced elevation of neutrophil p50 activity was abolished by simvastatin. In conclusion, our data provide further evidence of the ability of simvastatin to inhibit neutrophil adhesive interactions in response to inflammatory stimuli, both in vivo and in vitro. Simvastatin appears to inhibit neutrophil adhesion by interfering in TNF-induced cytoskeletal rearrangements, in association with the inhibition of Rho A activity, NFκB translocation and, consequently, β 2 -integrin activity. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Whole-genome duplication increases tumor cell sensitivity to MPS1 inhibition.

    PubMed

    Jemaà, Mohamed; Manic, Gwenola; Lledo, Gwendaline; Lissa, Delphine; Reynes, Christelle; Morin, Nathalie; Chibon, Frédéric; Sistigu, Antonella; Castedo, Maria; Vitale, Ilio; Kroemer, Guido; Abrieu, Ariane

    2016-01-05

    Several lines of evidence indicate that whole-genome duplication resulting in tetraploidy facilitates carcinogenesis by providing an intermediate and metastable state more prone to generate oncogenic aneuploidy. Here, we report a novel strategy to preferentially kill tetraploid cells based on the abrogation of the spindle assembly checkpoint (SAC) via the targeting of TTK protein kinase (better known as monopolar spindle 1, MPS1). The pharmacological inhibition as well as the knockdown of MPS1 kills more efficiently tetraploid cells than their diploid counterparts. By using time-lapse videomicroscopy, we show that tetraploid cells do not survive the aborted mitosis due to SAC abrogation upon MPS1 depletion. On the contrary diploid cells are able to survive up to at least two more cell cycles upon the same treatment. This effect might reflect the enhanced difficulty of cells with whole-genome doubling to tolerate a further increase in ploidy and/or an elevated level of chromosome instability in the absence of SAC functions. We further show that MPS1-inhibited tetraploid cells promote mitotic catastrophe executed by the intrinsic pathway of apoptosis, as indicated by the loss of mitochondrial potential, the release of the pro-apoptotic cytochrome c from mitochondria, and the activation of caspases. Altogether, our results suggest that MPS1 inhibition could be used as a therapeutic strategy for targeting tetraploid cancer cells.

  7. Protein inhibitor of activated STAT3 inhibits adipogenic gene expression

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Deng Jianbei; Hua Kunjie; Caveney, Erica J.

    2006-01-20

    Protein inhibitor of activated STAT3 (PIAS3), a cytokine-induced repressor of signal transducer and activator of transcription 3 (STAT3) and a modulator of a broad array of nuclear proteins, is expressed in white adipose tissue, but its role in adipogenesis is not known. Here, we determined that PIAS3 was constitutively expressed in 3T3-L1 cells at all stages of adipogenesis. However, it translocated from the nucleus to the cytoplasm 4 days after induction of differentiation by isobutylmethylxanthine, dexamethasone, and insulin (MDI). In ob/ob mice, PIAS3 expression was increased in white adipose tissue depots compared to lean mice and was found in themore » cytoplasm of adipocytes. Overexpression of PIAS3 in differentiating preadipocytes, which localized primarily to the nucleus, inhibited mRNA level gene expression of adipogenic transcription factors C/EBP{alpha} and PPAR{gamma}, as well as their downstream target genes aP2 and adiponectin. PIAS3 also inhibited C/EBP{alpha} promoter activation mediated specifically by insulin, but not dexamethasone or isobutylmethylxanthine. Taken together, these data suggest that PIAS3 may play an inhibitory role in adipogenesis by modulating insulin-activated transcriptional activation events. Increased PIAS3 expression in adipose tissue may play a role in the metabolic disturbances of obesity.« less

  8. Inhibition of telomerase activity by oleanane triterpenoid CDDO-Me in pancreatic cancer cells is ROS-dependent.

    PubMed

    Deeb, Dorrah; Gao, Xiaohua; Liu, Yongbo; Varma, Nadimpalli R S; Arbab, Ali S; Gautam, Subhash C

    2013-03-13

    Methyl-2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oate (CDDO-Me) is a synthetic derivative of oleanolic acid, a triterpene, with apoptosis-inducing activity in a wide range of cancer cells. Induction of apoptosis by CDDO-Me is associated with the generation of reactive oxygen species (ROS) and inhibition of telomerase activity. In the present study, we investigated the role of ROS in inhibition of telomerase by CDDO-me. Treatment of MiaPaCa-2 and Panc-1 pancreatic cancer cell lines with CDDO-Me induced the production of hydrogen peroxide and superoxide anions and inhibited the telomerase activity. Pretreatment of cells with N-acetylcycsteine, a general purpose antioxidant or overexpression of glutathione peroxidase (GPx) or superoxide dismutase-1 (SOD-1) blocked the telomerase inhibitory activity of CDDO-Me. Furthermore, blocking ROS generation also prevented the inhibition of hTERT gene expression, hTERT protein production and expression of a number of hTERT-regulatory proteins by CDDO-Me (e.g., c-Myc, Sp1, NF-κB and p-Akt). Data also showed that Akt plays an important role in the activation of telomerase activity. Together, these data suggest that inhibition of telomerase activity by CDDO-Me is mediated through a ROS-dependent mechanism; however, more work is needed to fully understand the role of ROS in down-regulation of hTERT gene and hTERT-regulatory proteins by CDDO-Me.

  9. Circulating Th1 cell-type Tfh cells that exhibit impaired B cell help are preferentially activated during acute malaria in children

    PubMed Central

    Obeng-Adjei, Nyamekye; Portugal, Silvia; Tran, Tuan M.; Yazew, Takele B.; Skinner, Jeff; Li, Shanping; Jain, Aarti; Felgner, Philip L.; Doumbo, Ogobara K.; Kayentao, Kassoum; Ongoiba, Aissata; Traore, Boubacar; Crompton, Peter D.

    2015-01-01

    SUMMARY Malaria-specific antibody responses are short-lived in children, leaving them susceptible to repeated bouts of febrile malaria. The cellular and molecular mechanisms underlying this apparent immune deficiency are poorly understood. Recently, T follicular helper (Tfh) cells have been shown to play a critical role in generating long-lived antibody responses. We show that Malian children have resting PD-1+CXCR5+CD4+ Tfh cells in circulation that resemble germinal center Tfh cells phenotypically and functionally. Within this population PD-1+CXCR5+CXCR3− Tfh cells are superior to Th1-polarized PD-1+CXCR5+CXCR3+ Tfh cells in helping B cells. Longitudinally, we observed that malaria drives Th1 cytokine responses, and accordingly, the less functional Th1-polarized Tfh subset was preferentially activated and its activation did not correlate with antibody responses. These data provide insights into the Tfh cell biology underlying suboptimal antibody responses to malaria in children, and suggest that vaccine strategies that promote CXCR3− Tfh cell responses may improve malaria vaccine efficacy. PMID:26440897

  10. Neural activation patterns during response inhibition distinguish adolescents with ADHD, their unaffected siblings, and healthy controls

    PubMed Central

    van Rooij, Daan; Hoekstra, Pieter J.; Mennes, Maarten; von Rhein, Daniel; Thissen, Andrieke J.A.M.; Heslenfeld, Dirk; Zwiers, Marcel P.; Faraone, Stephen V.; Oosterlaan, Jaap; Franke, Barbara; Rommelse, Nanda; Buitelaar, Jan K.; Hartman, Catharina A.

    2015-01-01

    Objective Impaired response inhibition is a key executive function deficit of attention-deficit/hyperactivity disorder (ADHD). Still, behavioral response inhibition measures do not consistently differentiate individuals with ADHD from unaffected individuals. We therefore investigated the neural correlates of response inhibition as well as the familial nature of these neural correlates. Methods fMRI measurements of neural activation during the stop-signal task along with behavioral measures of response inhibition were obtained in adolescents and young adults with ADHD (N=185), their unaffected siblings (N=111), and healthy controls (N=124). Results Stop-signal reaction times were longer in participants with ADHD, but not in their unaffected siblings, while reaction time variability and error rates were higher in both groups than in controls. Neural hypoactivation was observed in frontal-striatal and frontal-parietal networks of participants with ADHD and unaffected siblings compared to controls, whereby activation in inferior frontal and temporal/parietal nodes in unaffected siblings was intermediate between that of participants with ADHD and controls. Furthermore, neural activation in inferior frontal nodes correlated with stop-signal reaction times, and activation in both inferior frontal and temporal/parietal nodes correlated with ADHD severity. Conclusions Neural activation alterations in ADHD are more robust than behavioral response inhibition deficits and explain variance in response inhibition and ADHD severity. Although only affected participants with ADHD have deficient response inhibition, hypoactivation in inferior frontal and temporal-parietal nodes in unaffected siblings support the familial nature of the underlying neural process. Hypoactivation in these nodes may be useful as endophenotypes that extend beyond the affected individuals in the family. PMID:25615565

  11. The adaptor protein Crk controls activation and inhibition of natural killer cells.

    PubMed

    Liu, Dongfang; Peterson, Mary E; Long, Eric O

    2012-04-20

    Natural killer (NK) cell inhibitory receptors recruit tyrosine phosphatases to prevent activation, induce phosphorylation and dissociation of the small adaptor Crk from cytoskeleton scaffold complexes, and maintain NK cells in a state of responsiveness to subsequent activation events. How Crk contributes to inhibition is unknown. We imaged primary NK cells over lipid bilayers carrying IgG1 Fc to stimulate CD16 and human leukocyte antigen (HLA)-E to inhibit through receptor CD94-NKG2A. HLA-E alone induced Crk phosphorylation in NKG2A(+) NK cells. At activating synapses with Fc alone, Crk was required for the movement of Fc microclusters and their ability to trigger activation signals. At inhibitory synapses, HLA-E promoted central accumulation of both Fc and phosphorylated Crk and blocked the Fc-induced buildup of F-actin. We propose a unified model for inhibitory receptor function: Crk phosphorylation prevents essential Crk-dependent activation signals and blocks F-actin network formation, thereby reducing constraints on subsequent engagement of activation receptors. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Rapid runoff via shallow throughflow and deeper preferential flow in a boreal catchment underlain by frozen silt (Alaska, USA)

    USGS Publications Warehouse

    Koch, Joshua C.; Ewing, Stephanie A.; Striegl, Robert G.; McKnight, Diane M.

    2013-01-01

    In high-latitude catchments where permafrost is present, runoff dynamics are complicated by seasonal active-layer thaw, which may cause a change in the dominant flowpaths as water increasingly contacts mineral soils of low hydraulic conductivity. A 2-year study, conducted in an upland catchment in Alaska (USA) underlain by frozen, well-sorted eolian silt, examined changes in infiltration and runoff with thaw. It was hypothesized that rapid runoff would be maintained by flow through shallow soils during the early summer and deeper preferential flow later in the summer. Seasonal changes in soil moisture, infiltration, and runoff magnitude, location, and chemistry suggest that transport is rapid, even when soils are thawed to their maximum extent. Between June and September, a shift occurred in the location of runoff, consistent with subsurface preferential flow in steep and wet areas. Uranium isotopes suggest that late summer runoff erodes permafrost, indicating that substantial rapid flow may occur along the frozen boundary. Together, throughflow and deep preferential flow may limit upland boreal catchment water and solute storage, and subsequently biogeochemical cycling on seasonal to annual timescales. Deep preferential flow may be important for stream incision, network drainage development, and the release of ancient carbon to ecosystems

  13. Monoamine Oxidase-A Inhibition and Associated Antioxidant Activity in Plant Extracts with Potential Antidepressant Actions

    PubMed Central

    Guillén, Hugo

    2018-01-01

    Monoamine oxidase (MAO) catalyzes the oxidative deamination of amines and neurotransmitters and is involved in mood disorders, depression, oxidative stress, and adverse pharmacological reactions. This work studies the inhibition of human MAO-A by Hypericum perforatum, Peganum harmala, and Lepidium meyenii, which are reported to improve and affect mood and mental conditions. Subsequently, the antioxidant activity associated with the inhibition of MAO is determined in plant extracts for the first time. H. perforatum inhibited human MAO-A, and extracts from flowers gave the highest inhibition (IC50 of 63.6 μg/mL). Plant extracts were analyzed by HPLC-DAD-MS and contained pseudohypericin, hypericin, hyperforin, adhyperforin, hyperfirin, and flavonoids. Hyperforin did not inhibit human MAO-A and hypericin was a poor inhibitor of this isoenzyme. Quercetin and flavonoids significantly contributed to MAO-A inhibition. P. harmala seed extracts highly inhibited MAO-A (IC50 of 49.9 μg/L), being a thousand times more potent than H. perforatum extracts owing to its content of β-carboline alkaloids (harmaline and harmine). L. meyenii root (maca) extracts did not inhibit MAO-A. These plants may exert protective actions related to antioxidant effects. Results in this work show that P. harmala and H. perforatum extracts exhibit antioxidant activity associated with the inhibition of MAO (i.e., lower production of H2O2). PMID:29568754

  14. Inhibition of Propionibacterium acnes lipase activity by the antifungal agent ketoconazole.

    PubMed

    Unno, Mizuki; Cho, Otomi; Sugita, Takashi

    2017-01-01

    The common skin disease acne vulgaris is caused by Propionibacterium acnes. A lipase secreted by this microorganism metabolizes sebum and the resulting metabolites evoke inflammation in human skin. The antifungal drug ketoconazole inhibits P. acnes lipase activity. We previously showed that the drug also inhibits the growth of P. acnes. Thus, ketoconazole may serve as an alternative treatment for acne vulgaris, which is important because the number of antibiotic-resistant P. acnes strains has been increasing. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

  15. Phosphatidic Acid Sequesters Sec18p from cis-SNARE Complexes to Inhibit Priming.

    PubMed

    Starr, Matthew L; Hurst, Logan R; Fratti, Rutilio A

    2016-10-01

    Yeast vacuole fusion requires the activation of cis-SNARE complexes through priming carried out by Sec18p/N-ethylmaleimide sensitive factor and Sec17p/α-SNAP. The association of Sec18p with vacuolar cis-SNAREs is regulated in part by phosphatidic acid (PA) phosphatase production of diacylglycerol (DAG). Inhibition of PA phosphatase activity blocks the transfer of membrane-associated Sec18p to SNAREs. Thus, we hypothesized that Sec18p associates with PA-rich membrane microdomains before transferring to cis-SNARE complexes upon PA phosphatase activity. Here, we examined the direct binding of Sec18p to liposomes containing PA or DAG. We found that Sec18p preferentially bound to liposomes containing PA compared with those containing DAG by approximately fivefold. Additionally, using a specific PA-binding domain blocked Sec18p binding to PA-liposomes and displaced endogenous Sec18p from isolated vacuoles. Moreover, the direct addition of excess PA blocked the priming activity of isolated vacuoles in a manner similar to chemically inhibiting PA phosphatase activity. These data suggest that the conversion of PA to DAG facilitates the recruitment of Sec18p to cis-SNAREs. Purified vacuoles from yeast lacking the PA phosphatase Pah1p showed reduced Sec18p association with cis-SNAREs and complementation with plasmid-encoded PAH1 or recombinant Pah1p restored the interaction. Taken together, this demonstrates that regulating PA concentrations by Pah1p activity controls SNARE priming by Sec18p. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Mechanisms of mTORC1 activation by RHEB and inhibition by PRAS40.

    PubMed

    Yang, Haijuan; Jiang, Xiaolu; Li, Buren; Yang, Hyo J; Miller, Meredith; Yang, Angela; Dhar, Ankita; Pavletich, Nikola P

    2017-12-21

    The mechanistic target of rapamycin complex 1 (mTORC1) controls cell growth and metabolism in response to nutrients, energy levels, and growth factors. It contains the atypical kinase mTOR and the RAPTOR subunit that binds to the Tor signalling sequence (TOS) motif of substrates and regulators. mTORC1 is activated by the small GTPase RHEB (Ras homologue enriched in brain) and inhibited by PRAS40. Here we present the 3.0 ångström cryo-electron microscopy structure of mTORC1 and the 3.4 ångström structure of activated RHEB-mTORC1. RHEB binds to mTOR distally from the kinase active site, yet causes a global conformational change that allosterically realigns active-site residues, accelerating catalysis. Cancer-associated hyperactivating mutations map to structural elements that maintain the inactive state, and we provide biochemical evidence that they mimic RHEB relieving auto-inhibition. We also present crystal structures of RAPTOR-TOS motif complexes that define the determinants of TOS recognition, of an mTOR FKBP12-rapamycin-binding (FRB) domain-substrate complex that establishes a second substrate-recruitment mechanism, and of a truncated mTOR-PRAS40 complex that reveals PRAS40 inhibits both substrate-recruitment sites. These findings help explain how mTORC1 selects its substrates, how its kinase activity is controlled, and how it is activated by cancer-associated mutations.

  17. Liver δ-Aminolevulinate Dehydratase Activity is Inhibited by Neonicotinoids and Restored by Antioxidant Agents

    PubMed Central

    Sauer, Elisa; Moro, Angela M.; Brucker, Natália; Nascimento, Sabrina; Gauer, Bruna; Fracasso, Rafael; Gioda, Adriana; Beck, Ruy; Moreira, José C. F.; Eifler-Lima, Vera Lucia; Garcia, Solange Cristina

    2014-01-01

    Neonicotinoids represent the most used class of insecticides worldwide, and their precursor, imidacloprid, is the most widely marketed. The aim of this study was to evaluate the effect of imidacloprid on the activity of hepatic δ-aminolevulinate dehydratase (δ-ALA-D), protective effect of potential antioxidants against this potential effect and presence of chemical elements in the constitution of this pesticide. We observed that δ-ALA-D activity was significantly inhibited by imidacloprid at all concentrations tested in a dose-dependent manner. The IC50 value was obtained and used to evaluate the restoration of the enzymatic activity. δ-ALA-D inhibition was completely restored by addition of dithiotreitol (DTT) and partly by ZnCl2, demonstrating that the inhibition occurs by oxidation of thiol groups and by displacement of the Zn (II), which can be explained by the presence of chemical elements found in the constitution of pesticides. Reduced glutathione (GSH) had the best antioxidant effect against to δ-ALA-D inhibition caused by imidacloprid, followed by curcumin and resveratrol. It is well known that inhibition of the enzyme δ-ALA-D may result in accumulation of its neurotoxic substrate (δ-ALA), in this line, our results suggest that further studies are needed to investigate the possible neurotoxicity induced by neonicotinoids and the involvement of antioxidants in cases of poisoning by neonicotinoids. PMID:25402564

  18. Cathepsin L Inhibition Prevents Murine Autoimmune Diabetes via Suppression of CD8+ T Cell Activity

    PubMed Central

    Yamada, Akiko; Ishimaru, Naozumi; Arakaki, Rieko; Katunuma, Nobuhiko; Hayashi, Yoshio

    2010-01-01

    Background Type 1 diabetes (T1D) is an autoimmune disease resulting from defects in central and peripheral tolerance and characterized by T cell-mediated destruction of islet β cells. To determine whether specific lysosomal proteases might influence the outcome of a T cell–mediated autoimmune response, we examined the functional significance of cathepsin inhibition on autoimmune T1D-prone non-obese diabetic (NOD) mice. Methods and Findings Here it was found that specific inhibition of cathepsin L affords strong protection from cyclophosphamide (CY)-induced insulitis and diabetes of NOD mice at the advanced stage of CD8+ T cell infiltration via inhibiting granzyme activity. It was discovered that cathepsin L inhibition prevents cytotoxic activity of CD8+ T cells in the pancreatic islets through controlling dipeptidyl peptidase I activity. Moreover, the gene targeting for cathepsin L with application of in vivo siRNA administration successfully prevented CY-induced diabetes of NOD mice. Finally, cathepsin L mRNA expression of peripheral CD8+ T cells from NOD mice developing spontaneous T1D was significantly increased compared with that from control mice. Conclusions Our results identified a novel function of cathepsin L as an enzyme whose activity is essential for the progression of CD8+ T cell-mediated autoimmune diabetes, and inhibition of cathepsin L as a powerful therapeutic strategy for autoimmune diabetes. PMID:20877570

  19. The clerodane diterpene casearin J induces apoptosis of T-ALL cells through SERCA inhibition, oxidative stress, and interference with Notch1 signaling

    PubMed Central

    De Ford, C; Heidersdorf, B; Haun, F; Murillo, R; Friedrich, T; Borner, C; Merfort, I

    2016-01-01

    T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy that preferentially affects children and adolescents. Over 50% of human T-ALLs possess activating mutations of Notch1. The clerodane diterpene casearin J (CJ) is a natural product that inhibits the sarcoendoplasmatic reticulum calcium ATPase (SERCA) pump and induces cell death in leukemia cells, but the molecular mechanism of cytotoxicity remains poorly understood. Here we show that owing to SERCA pump inhibition, CJ induces depletion of the endoplasmic reticulum calcium pools, oxidative stress, and apoptosis via the intrinsic signaling pathway. Moreover, Notch1 signaling is reduced in T-ALL cells with auto-activating mutations in the HD-domain of Notch1, but not in cells that do not depend on Notch1 signaling. CJ also provoked a slight activation of NF-κB, and consistent with this notion a combined treatment of CJ and the NF-κB inhibitor parthenolide (Pt) led to a remarkable synergistic cell death in T-ALL cells. Altogether, our data support the concept that inhibition of the SERCA pump may be a novel strategy for the treatment of T-ALL with HD-domain-mutant Notch1 receptors and that additional treatment with the NF-κB inhibitor parthenolide may have further therapeutic benefits. PMID:26821066

  20. Pomegranate ellagitannins inhibit α-glucosidase activity in vitro and reduce starch digestibility under simulated gastro-intestinal conditions.

    PubMed

    Bellesia, Andrea; Verzelloni, Elena; Tagliazucchi, Davide

    2015-02-01

    Pomegranate extract was tested for its ability to inhibit α-amylase and α-glucosidase activity. Pomegranate extract strongly inhibited rat intestinal α-glucosidase in vitro whereas it was a weak inhibitor of porcine α-amylase. The inhibitory activity was recovered in an ellagitannins-enriched fraction and punicalagin, punicalin, and ellagic acid were identified as α-glucosidase inhibitors (IC(50) of 140.2, 191.4, and 380.9 μmol/L, respectively). Kinetic analysis suggested that the pomegranate extract and ellagitannins inhibited α-glucosidase activity in a mixed mode. The inhibitory activity was demonstrated using an in vitro digestion system, mimicking the physiological gastro-intestinal condition, and potatoes as food rich in starch. Pre-incubation between ellagitannins and α-glucosidase increased the inhibitory activity, suggesting that they acted by binding to α-glucosidase. During digestion punicalin and punicalagin concentration decreased. Despite this loss, the pomegranate extract retained high inhibitory activity. This study suggests that pomegranate ellagitannins may inhibit α-glucosidase activity in vitro possibly affecting in vivo starch digestion.

  1. Small molecule schweinfurthins selectively inhibit cancer cell proliferation and mTOR/AKT signaling by interfering with trans-Golgi-network trafficking

    PubMed Central

    Bao, Xingfeng; Zheng, Wanjun; Sugi, Naoko Hata; Agarwala, Kishan L; Xu, Qunli; Wang, Zichun; Tendyke, Karen; Lee, Winnie; Parent, Lana; Li, Wei; Cheng, Hongsheng; Shen, Yongchun; Taylor, Noel; Dezso, Zoltan; Du, Hong; Kotake, Yoshihiko; Zhao, Nanding; Wang, John; Postema, Maarten; Woodall-Jappe, Mary; Takase, Yasutaka; Uenaka, Toshimitsu; Kingston, David G I; Nomoto, Kenichi

    2015-01-01

    Natural compound schweinfurthins are of considerable interest for novel therapy development because of their selective anti-proliferative activity against human cancer cells. We previously reported the isolation of highly active schweinfurthins E-H, and in the present study, mechanisms of the potent and selective anti-proliferation were investigated. We found that schweinfurthins preferentially inhibited the proliferation of PTEN deficient cancer cells by indirect inhibition of AKT phosphorylation. Mechanistically, schweinfurthins and their analogs arrested trans-Golgi-network trafficking, an intracellular vesicular trafficking system, resulting in the induction of endoplasmic reticulum stress and the suppression of both lipid raft-mediated PI3K activation and mTOR/RheB complex formation, which collectively led to an effective inhibition of mTOR/AKT signaling. The trans-Golgi-network traffic arresting effect of schweinfurthins was associated with their in vitro binding activity to oxysterol-binding proteins that are known to regulate intracellular vesicular trafficking. Moreover, schweinfurthins were found to be highly toxic toward PTEN-deficient B cell lymphoma cells, and displayed 2 orders of magnitude lower activity toward normal human peripheral blood mononuclear cells and primary fibroblasts in vitro. These results revealed a previously unrecognized role of schweinfurthins in regulating trans-Golgi-network trafficking, and linked mechanistically this cellular effect with mTOR/AKT signaling and with cancer cell survival and growth. Our findings suggest the schweinfurthin class of compounds as a novel approach to modulate oncogenic mTOR/AKT signaling for cancer treatment. PMID:25729885

  2. Effects of memantine on the excitation-inhibition balance in prefrontal cortex.

    PubMed

    Povysheva, Nadezhda V; Johnson, Jon W

    2016-12-01

    Memantine is one of the few drugs currently approved for treatment of Alzheimer's disease (AD). The clinical effects of memantine are thought to be associated with inhibition of NMDA receptors (NMDARs). Surprisingly, other open-channel NMDAR blockers have unacceptable side effects that prevent their consideration for AD treatment. One of the mechanisms proposed to explain the therapeutic benefits of memantine involves preferential decrease of excitatory drive to inhibitory neurons in the cortical circuitry and consequent changes in balance between excitation and inhibition (E/I). In this study we addressed effects of memantine on E/I balance in the prefrontal cortex (PFC). We found that a moderate concentration of memantine shifted E/I balance away from inhibition in the PFC circuitry. Indeed, memantine decreased the frequency and amplitude of spontaneous inhibitory postsynaptic currents in pyramidal neurons while leaving spontaneous excitatory postsynaptic currents unaffected. These circuitry effects of memantine were occluded by the competitive NMDAR inhibitor AP-5, and thus are associated with NMDAR inhibition. We also found that memantine decreased feed-forward disynaptic inhibitory input to pyramidal neurons, which is thought to be mediated by parvalbumin (PV)-positive interneurons. Accordingly, memantine caused a greater decrease of the amplitude of NMDAR-mediated synaptic responses in PV-positive interneurons than in pyramidal neurons. Finally, memantine reduced firing activity in PV-positive interneurons while increasing firing in pyramidal neurons. This study elucidates a novel mechanism of action of memantine associated with shifting of the E/I balance away from inhibition in neocortical circuitry, and provides important insights for AD drug development. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Suppression of Brain Mast Cells Degranulation Inhibits Microglial Activation and Central Nervous System Inflammation.

    PubMed

    Dong, Hongquan; Zhang, Xiang; Wang, Yiming; Zhou, Xiqiao; Qian, Yanning; Zhang, Shu

    2017-03-01

    Brain inflammation has a critical role in the pathophysiology of brain diseases. Microglia, the resident immune cells in the brain, play an important role in brain inflammation, while brain mast cells are the "first responder" in the injury rather than microglia. Functional aspects of mast cell-microglia interactions remain poorly understood. Our results demonstrated that site-directed injection of the "mast cell degranulator" compound 48/80 (C48/80) in the hypothalamus induced mast cell degranulation, microglial activation, and inflammatory factor production, which initiated the acute brain inflammatory response. "Mast cell stabilizer" disodium cromoglycate (cromolyn) inhibited this effect, including decrease of inflammatory cytokines, reduced microglial activation, inhibition of MAPK and AKT pathways, and repression of protein expression of histamine receptor 1 (H 1 R), histamine receptor 4 (H 4 R), protease-activated receptor 2 (PAR2), and toll-like receptor 4 (TLR4) in microglia. We also demonstrated that C48/80 had no effect on microglial activation in mast cell-deficient Kit W-sh/W-sh mice. These results implicate that activated brain mast cells trigger microglial activation and stabilization of mast cell inhibits microglial activation-induced central nervous system (CNS) inflammation. Interactions between mast cells and microglia could constitute a new and unique therapeutic target for CNS immune inflammation-related diseases.

  4. Isolation, Identification, and Xanthine Oxidase Inhibition Activity of Alkaloid Compound from Peperomia pellucida

    NASA Astrophysics Data System (ADS)

    Fachriyah, E.; Ghifari, M. A.; Anam, K.

    2018-04-01

    The research of the isolation and xanthine oxidation inhibition activity of alkaloid compound from Peperomia pellucida has been carried out. Alkaloid extract is isolated by column chromatography and preparative TLC. Alkaloid isolate is identified spectroscopically by UV-Vis spectrophotometer, FT-IR, and LC-MS/MS. Xanthine oxidase inhibition activity is carried out by in vitro assay. The result showed that the alkaloid isolated probably has piperidine basic structure. The alkaloid isolate has N-H, C-H, C = C, C = O, C-N, C-O-C groups and the aromatic ring. The IC50 values of ethanol and alkaloid extract are 71.6658 ppm and 76.3318 ppm, respectively. Alkaloid extract of Peperomia pellucida showed higher activity than ethanol extract.

  5. Preferential interactions promote blind cooperation and informed defection.

    PubMed

    Pérez-Escudero, Alfonso; Friedman, Jonathan; Gore, Jeff

    2016-12-06

    It is common sense that costs and benefits should be carefully weighed before deciding on a course of action. However, we often disapprove of people who do so, even when their actual decision benefits us. For example, we prefer people who directly agree to do us a favor over those who agree only after securing enough information to ensure that the favor will not be too costly. Why should we care about how people make their decisions, rather than just focus on the decisions themselves? Current models show that punishment of information gathering can be beneficial because it forces blind decisions, which under some circumstances enhances cooperation. Here we show that aversion to information gathering can be beneficial even in the absence of punishment, due to a different mechanism: preferential interactions with reliable partners. In a diverse population where different people have different-and unknown-preferences, those who seek additional information before agreeing to cooperate reveal that their preferences are close to the point where they would choose not to cooperate. Blind cooperators are therefore more likely to keep cooperating even if conditions change, and aversion to information gathering helps to interact preferentially with them. Conversely, blind defectors are more likely to keep defecting in the future, leading to a preference for informed defectors over blind ones. Both mechanisms-punishment to force blind decisions and preferential interactions-give qualitatively different predictions, which may enable experimental tests to disentangle them in real-world situations.

  6. Intracellular mature IL-37 suppresses tumor metastasis via inhibiting Rac1 activation.

    PubMed

    Li, Y; Zhao, M; Guo, C; Chu, H; Li, W; Chen, X; Wang, X; Li, Y; Jia, Y; Koussatidjoa, S; Zhu, F; Wang, J; Wang, X; Wang, Q; Zhao, W; Shi, Y; Chen, W; Zhang, L

    2018-02-22

    IL-37, a newly found anti-inflammatory cytokine of the IL-1 family, has both extracellular and intracellular functions. Accumulating evidences indicate that it is also involved in tumor progression. However, the mechanism and its intracellular target are unclear. In this study, clinical data from 84 patients showed that loss or reduced expression of IL-37 in lung adenocarcinoma tissues was significantly associated with tumor metastasis. We further provided evidence that IL-37 inhibited effectively tumor metastasis in vitro and in vivo. Moreover, we uncovered a novel mechanism by which IL-37 suppressed tumor cell migration via its intracellular mature form (amino acids 46-218). Intracellular mature form of IL-37, but not its extracellular form, markedly inhibited migration of multiple kinds of tumor cells through inhibiting Rac1 activation. Mechanistically, intracellular mature IL-37 directly bound to the CAAX motif in the C-terminal hypervariable region of Rac1, and then inhibited Rac1 membrane translocation and subsequent downstream signaling. Our research identifies intracellular mature IL-37 as a novel endogenous inhibitor of Rac1. Given the crucial roles of Rac1 in tumor angiogenesis and metastasis, intracellular mature IL-37 might serve as a potential strategy for the control of Rac1 activity and tumor progression.

  7. Naringin Attenuates Cerebral Ischemia-Reperfusion Injury Through Inhibiting Peroxynitrite-Mediated Mitophagy Activation.

    PubMed

    Feng, Jinghan; Chen, Xingmiao; Lu, Shengwen; Li, Wenting; Yang, Dan; Su, Weiwei; Wang, Xijun; Shen, Jiangang

    2018-04-07

    Excessive autophagy/mitophagy plays important roles during cerebral ischemia-reperfusion (I/R) injury. Peroxynitrite (ONOO - ), a representative reactive nitrogen species, mediates excessive mitophagy activation and exacerbates cerebral I/R injury. In the present study, we tested the hypothesis that naringin, a natural antioxidant, could inhibit ONOO - -mediated mitophagy activation and attenuate cerebral I/R injury. Firstly, we demonstrated that naringin possessed strong ONOO - scavenging capability and also inhibited the production of superoxide and nitric oxide in SH-SY5Y cells exposed to 10 h oxygen-glucose-deprivation plus 14 h of reoxygenation or ONOO - donor 3-morpholinosydnonimine conditions. Naringin also inhibited the expression of NADPH oxidase subunits and iNOS in rat brains subjected to 2 h ischemia plus 22 h reperfusion. Next, we found that naringin was able to cross the blood-brain barrier, and naringin decreased neurological deficit score, reduced infarct size, and attenuated apoptotic cell death in the ischemia-reperfused rat brains. Furthermore, naringin reduced 3-nitrotyrosine formation, decreased the ratio of LC3-II to LC3-I in mitochondrial fraction, and inhibited the translocation of Parkin to the mitochondria. Taken together, naringin could be a potential therapeutic agent to prevent the brain from I/R injury via attenuating ONOO - -mediated excessive mitophagy.

  8. Regorafenib inhibited gastric cancer cells growth and invasion via CXCR4 activated Wnt pathway.

    PubMed

    Lin, Xiao-Lin; Xu, Qi; Tang, Lei; Sun, Li; Han, Ting; Wang, Li-Wei; Xiao, Xiu-Ying

    2017-01-01

    Regorafenib is an oral small-molecule multi kinase inhibitor. Recently, several clinical trials have revealed that regorafenib has an anti-tumor activity in gastric cancer. However, only part of patients benefit from regorafenib, and the mechanisms of regorafenib's anti-tumor effect need further demonstrating. In this study, we would assess the potential anti-tumor effects and the underlying mechanisms of regorafenib in gastric cancer cells, and explore novel biomarkers for patients selecting of regorafenib. The anti-tumor effects of regorafenib on gastric cancer cells were analyzed via cell proliferation and invasion. The underlying mechanisms were demonstrated using molecular biology techniques. We found that regorafenib inhibited cell proliferation and invasion at the concentration of 20μmol/L and in a dose dependent manner. The anti-tumor effects of regorafenib related to the decreased expression of CXCR4, and elevated expression and activation of CXCR4 could reverse the inhibition effect of regorafenib on gastric cancer cells. Further studies revealed that regorafenib reduced the transcriptional activity of Wnt/β-Catenin pathway and led to decreased expression of Wnt pathway target genes, while overexpression and activation of CXCR4 could attenuate the inhibition effect of regorafenib on Wnt/β-Catenin pathway. Our findings demonstrated that regorafenib effectively inhibited cell proliferation and invasion of gastric cancer cells via decreasing the expression of CXCR4 and further reducing the transcriptional activity of Wnt/β-Catenin pathway.

  9. Ultraviolet B inhibition of DNMT1 activity via AhR activation dependent SIRT1 suppression in CD4+ T cells from systemic lupus erythematosus patients.

    PubMed

    Wu, Zhouwei; Mei, Xingyu; Ying, Zuolin; Sun, Yue; Song, Jun; Shi, Weimin

    2017-06-01

    Previous studies have reported that ultraviolet B (UVB) inhibits DNA methyltransferase1 (DNMT1) activity in CD4+ T cells from systemic lupus erythematosus (SLE) patients. Silent mating type information regulation 2 homolog 1 (SIRT1) is a type of Class III histone deacetylases (HDACs), and has been reported to play roles in the pathogenesis of different autoimmune diseases and can modulate DNMT1 activity. Moreover, aryl hydrocarbon receptor (AhR) has been reported to link UVB with SLE. However, the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells remain largely unknown. To elucidate the exact mechanisms by which DNMT1 activity is inhibited by UVB in lupus CD4+ T cells. Twenty-two newly diagnosed active SLE patients and 30 healthy controls were enrolled in the study. CD4+ T cells were isolated, cultured and treated. DNMT1 activity assay, quantitative real-time PCR (qRT-PCR), Western blotting, RNA interference using small interfering RNA and Chromatin Immunoprecipitation (ChIP) assay were employed. DNMT1 activity was inhibited in si-SIRT1-transfected CD4+ T cells, and increased by the established SIRT1 activator, SRT1720. Moreover, the mRNA and protein expression of SIRT1 were suppressed by UVB exposure in lupus CD4+ T cells. UVB-inhibited DNMT1 activity was reversed by SRT1720 in si-control-transfected lupus CD4+ T cells, but not in si-SIRT1-transfected lupus CD4 + T cells. Furthermore, AhR activation by VAF347 reduced the mRNA and protein expression of SIRT1. ChIP using an antibody against AhR in normal CD4+ T cells revealed a 16-fold stronger signal at the site about 1.6kb upstream from the translation start site of the SIRT1 promoter. Finally, UVB could activate AhR and inhibit the mRNA and protein expression of SIRT1. AhR knockdown abrogated the inhibition of UVB-mediated SIRT1 mRNA and protein expression and DNMT1 activity in lupus CD4+ T cells. UVB suppressed SIRT1 expression via activating AhR, and subsequently inhibited DNMT1

  10. Pyridine-substituted thiazolylphenol derivatives: Synthesis, modeling studies, aromatase inhibition, and antiproliferative activity evaluation.

    PubMed

    Ertas, Merve; Sahin, Zafer; Berk, Barkin; Yurttas, Leyla; Biltekin, Sevde N; Demirayak, Seref

    2018-04-01

    Drugs used in breast cancer treatments target the suppression of estrogen biosynthesis. During this suppression, the main goal is to inhibit the aromatase enzyme that is responsible for the cyclization and structuring of estrogens either with steroid or non-steroidal-type inhibitors. Non-steroidal derivatives generally have a planar aromatic structure attached to the triazole ring system in their structures, which inhibits hydroxylation reactions during aromatization by coordinating the heme group. Bioisosteric replacement of the triazole ring system and development of aromatic/cyclic structures of the side chain can increase the selectivity for aromatase enzyme inhibition. In this study, pyridine-substituted thiazolylphenol derivatives, which are non-steroidal triazole bioisosteres, were synthesized using the Hantzsch method, and physical analysis and structural determination studies were performed. The IC 50 values of the compounds were determined by a fluorescence-based aromatase inhibition assay. Then, their antiproliferative activities on the MCF7 and HEK 293 cell lines were evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Furthermore, the crystal structure of human placental aromatase was subjected to a series of docking experiments to identify the possible interactions between the most active structure and the active site. Lastly, an in silico technique was performed to analyze and predict the drug-likeness, molecular and ADME properties of the synthesized molecules. © 2018 Deutsche Pharmazeutische Gesellschaft.

  11. Graviola inhibits hypoxia-induced NADPH oxidase activity in prostate cancer cells reducing their proliferation and clonogenicity

    PubMed Central

    Deep, Gagan; Kumar, Rahul; Jain, Anil K.; Dhar, Deepanshi; Panigrahi, Gati K.; Hussain, Anowar; Agarwal, Chapla; El-Elimat, Tamam; Sica, Vincent P.; Oberlies, Nicholas H.; Agarwal, Rajesh

    2016-01-01

    Prostate cancer (PCa) is the leading malignancy among men. Importantly, this disease is mostly diagnosed at early stages offering a unique chemoprevention opportunity. Therefore, there is an urgent need to identify and target signaling molecules with higher expression/activity in prostate tumors and play critical role in PCa growth and progression. Here we report that NADPH oxidase (NOX) expression is directly associated with PCa progression in TRAMP mice, suggesting NOX as a potential chemoprevention target in controlling PCa. Accordingly, we assessed whether NOX activity in PCa cells could be inhibited by Graviola pulp extract (GPE) that contains unique acetogenins with strong anti-cancer effects. GPE (1–5 μg/ml) treatment strongly inhibited the hypoxia-induced NOX activity in PCa cells (LNCaP, 22Rv1 and PC3) associated with a decrease in the expression of NOX catalytic and regulatory sub-units (NOX1, NOX2 and p47phox). Furthermore, GPE-mediated NOX inhibition was associated with a strong decrease in nuclear HIF-1α levels as well as reduction in the proliferative and clonogenic potential of PCa cells. More importantly, GPE treatment neither inhibited NOX activity nor showed any cytotoxicity against non-neoplastic prostate epithelial PWR-1E cells. Overall, these results suggest that GPE could be useful in the prevention of PCa progression via inhibiting NOX activity. PMID:26979487

  12. Chemical inhibition of a subset of Arabidopsis thaliana GSK3-like kinases activates brassinosteroid signaling.

    PubMed

    De Rybel, Bert; Audenaert, Dominique; Vert, Grégory; Rozhon, Wilfried; Mayerhofer, Juliane; Peelman, Frank; Coutuer, Silvie; Denayer, Tinneke; Jansen, Leentje; Nguyen, Long; Vanhoutte, Isabelle; Beemster, Gerrit T S; Vleminckx, Kris; Jonak, Claudia; Chory, Joanne; Inzé, Dirk; Russinova, Eugenia; Beeckman, Tom

    2009-06-26

    Glycogen synthase kinase 3 (GSK3) is a key regulator in signaling pathways in both animals and plants. Three Arabidopsis thaliana GSK3s are shown to be related to brassinosteroid (BR) signaling. In a phenotype-based compound screen we identified bikinin, a small molecule that activates BR signaling downstream of the BR receptor. Bikinin directly binds the GSK3 BIN2 and acts as an ATP competitor. Furthermore, bikinin inhibits the activity of six other Arabidopsis GSK3s. Genome-wide transcript analyses demonstrate that simultaneous inhibition of seven GSK3s is sufficient to activate BR responses. Our data suggest that GSK3 inhibition is the sole activation mode of BR signaling and argues against GSK3-independent BR responses in Arabidopsis. The opportunity to generate multiple and conditional knockouts in key regulators in the BR signaling pathway by bikinin represents a useful tool to further unravel regulatory mechanisms.

  13. 19 CFR 10.616 - Verification and justification of claim for preferential tariff treatment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RATE, ETC. Dominican Republic-Central America-United States Free Trade Agreement Origin Verifications... preferential tariff treatment. 10.616 Section 10.616 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... verification of a claim for preferential tariff treatment under CAFTA-DR for goods imported into the United...

  14. Estimating preferential flow in karstic aquifers using statistical mixed models.

    PubMed

    Anaya, Angel A; Padilla, Ingrid; Macchiavelli, Raul; Vesper, Dorothy J; Meeker, John D; Alshawabkeh, Akram N

    2014-01-01

    Karst aquifers are highly productive groundwater systems often associated with conduit flow. These systems can be highly vulnerable to contamination, resulting in a high potential for contaminant exposure to humans and ecosystems. This work develops statistical models to spatially characterize flow and transport patterns in karstified limestone and determines the effect of aquifer flow rates on these patterns. A laboratory-scale Geo-HydroBed model is used to simulate flow and transport processes in a karstic limestone unit. The model consists of stainless steel tanks containing a karstified limestone block collected from a karst aquifer formation in northern Puerto Rico. Experimental work involves making a series of flow and tracer injections, while monitoring hydraulic and tracer response spatially and temporally. Statistical mixed models (SMMs) are applied to hydraulic data to determine likely pathways of preferential flow in the limestone units. The models indicate a highly heterogeneous system with dominant, flow-dependent preferential flow regions. Results indicate that regions of preferential flow tend to expand at higher groundwater flow rates, suggesting a greater volume of the system being flushed by flowing water at higher rates. Spatial and temporal distribution of tracer concentrations indicates the presence of conduit-like and diffuse flow transport in the system, supporting the notion of both combined transport mechanisms in the limestone unit. The temporal response of tracer concentrations at different locations in the model coincide with, and confirms the preferential flow distribution generated with the SMMs used in the study. © 2013, National Ground Water Association.

  15. The Role of Factor Inhibiting HIF (FIH-1) in Inhibiting HIF-1 Transcriptional Activity in Glioblastoma Multiforme

    PubMed Central

    Liu, Fengming; Wu, Gang; Schroeder, Mark A.; Lau, Julie S.; Mukhopadhyay, Debabrata; Jiang, Shi-Wen; O'Neill, Brian Patrick; Datta, Kaustubh; Li, Jinping

    2014-01-01

    Glioblastoma multiforme (GBM) accounts for about 38% of primary brain tumors in the United States. GBM is characterized by extensive angiogenesis induced by vascular growth factors and cytokines. The transcription of these growth factors and cytokines is regulated by the Hypoxia-Inducible-Factor-1(HIF-1), which is a key regulator mediating the cellular response to hypoxia. It is known that Factor Inhibiting HIF-1, or FIH-1, is also involved in the cellular response to hypoxia and has the capability to physically interact with HIF-1 and block its transcriptional activity under normoxic conditions. Delineation of the regulatory role of FIH-1 will help us to better understand the molecular mechanism responsible for tumor growth and progression and may lead to the design of new therapies targeting cellular pathways in response to hypoxia. Previous studies have shown that the chromosomal region of 10q24 containing the FIH-1 gene is often deleted in GBM, suggesting a role for the FIH-1 in GBM tumorigenesis and progression. In the current study, we found that FIH-1 is able to inhibit HIF-mediated transcription of GLUT1 and VEGF-A, even under hypoxic conditions in human glioblastoma cells. FIH-1 has been found to be more potent in inhibiting HIF function than PTEN. This observation points to the possibility that deletion of 10q23-24 and loss or decreased expression of FIH-1 gene may lead to a constitutive activation of HIF-1 activity, an alteration of HIF-1 targets such as GLUT-1 and VEGF-A, and may contribute to the survival of cancer cells in hypoxia and the development of hypervascularization observed in GBM. Therefore FIH-1 can be potential therapeutic target for the treatment of GBM patients with poor prognosis. PMID:24465898

  16. Preferential pathways in complex fracture systems and their influence on large scale transport

    NASA Astrophysics Data System (ADS)

    Willmann, M.; Mañé, R.; Tyukhova, A.

    2017-12-01

    Many subsurface applications in complex fracture systems require large-scale predictions. Precise predictions are difficult because of the existence of preferential pathways at different scales. The intrinsic complexity of fracture systems increases within fractured sedimentary formations, because also the coupling of fractures and matrix has to be taken into account. This interplay of fracture system and the sedimentary matrix is strongly controlled by the actual fracture aperture of an individual fracture. And an effective aperture cannot be easily be determined because of the preferential pathways along the fracture plane. We investigate the influence of these preferential pathways on large scale solute transport and upscale the aperture. By explicitly modeling flow and particle tracking in individual fractures, we develop a new effective transport aperture, which is weighted by the aperture along the preferential paths, a Lagrangian aperture. We show that this new aperture is consistently larger than existing definitions of effective flow and transport apertures. Finally, we apply our results to a fractured sedimentary formation in Northern Switzerland.

  17. Pathological histone acetylation in Parkinson's disease: Neuroprotection and inhibition of microglial activation through SIRT 2 inhibition.

    PubMed

    Harrison, Ian F; Smith, Andrew D; Dexter, David T

    2018-02-14

    Parkinson's disease (PD) is associated with degeneration of nigrostriatal neurons due to intracytoplasmic inclusions composed predominantly of a synaptic protein called α-synuclein. Accumulations of α-synuclein are thought to 'mask' acetylation sites on histone proteins, inhibiting the action of histone acetyltransferase (HAT) enzymes in their equilibrium with histone deacetylases (HDACs), thus deregulating the dynamic control of gene transcription. It is therefore hypothesised that the misbalance in the actions of HATs/HDACs in neurodegeneration can be rectified with the use of HDAC inhibitors, limiting the deregulation of transcription and aiding neuronal homeostasis and neuroprotection in disorders such as PD. Here we quantify histone acetylation in the Substantia Nigra pars compacta (SNpc) in the brains of control, early and late stage PD cases to determine if histone acetylation is a function of disease progression. PD development is associated with Braak-dependent increases in histone acetylation. Concurrently, we show that as expected disease progression is associated with reduced markers of dopaminergic neurons and increased markers of activated microglia. We go on to demonstrate that in vitro, degenerating dopaminergic neurons exhibit histone hypoacetylation whereas activated microglia exhibit histone hyperacetylation. This suggests that the disease-dependent increase in histone acetylation observed in human PD cases is likely a combination of the contributions of both degenerating dopaminergic neurons and infiltrating activated microglia. The HDAC SIRT 2 has become increasingly implicated as a novel target for mediation of neuroprotection in PD: the neuronal and microglial specific effects of its inhibition however remain unclear. We demonstrate that SIRT 2 expression in the SNpc of PD brains remains relatively unchanged from controls and that SIRT 2 inhibition, via AGK2 treatment of neuronal and microglial cultures, results in neuroprotection of

  18. Vibrio parahaemolyticus Inhibition of Rho Family GTPase Activation Requires a Functional Chromosome I Type III Secretion System▿

    PubMed Central

    Casselli, Timothy; Lynch, Tarah; Southward, Carolyn M.; Jones, Bryan W.; DeVinney, Rebekah

    2008-01-01

    Vibrio parahaemolyticus is a leading cause of seafood-borne gastroenteritis; however, its virulence mechanisms are not well understood. The identification of type III secreted proteins has provided candidate virulence factors whose functions are still being elucidated. Genotypic strain variability contributes a level of complexity to understanding the role of different virulence factors. The ability of V. parahaemolyticus to inhibit Rho family GTPases and cause cytoskeletal disruption was examined with HeLa cells. After HeLa cells were infected, intracellular Rho activation was inhibited in response to external stimuli. In vitro activation of Rho, Rac, and Cdc42 isolated from infected HeLa cell lysates was also inhibited, indicating that the bacteria were specifically targeting GTPase activation. The inhibition of Rho family GTPase activation was retained for clinical and environmental isolates of V. parahaemolyticus and was dependent on a functional chromosome I type III secretion system (CI-T3SS). GTPase inhibition was independent of hemolytic toxin genotype and the chromasome II (CII)-T3SS. Rho inhibition was accompanied by a shift in the total actin pool to its monomeric form. These phenotypes were abrogated in a mutant strain lacking the CI-T3S effector Vp1686, suggesting that the inhibiting actin polymerization may be a downstream effect of Vp1686-dependent GTPase inhibition. Although Vp1686 has been previously characterized as a potential virulence factor in macrophages, our findings reveal an effect on cultured HeLa cells. The ability to inhibit Rho family GTPases independently of the CII-T3SS and the hemolytic toxins may provide insight into the mechanisms of virulence used by strains lacking these virulence factors. PMID:18347050

  19. Inhibition of S-adenosylmethionine decarboxylase and diamine oxidase activities by analogues of methylglyoxal bis(guanylhydrazone) and their cellular uptake during lymphocyte activation.

    PubMed Central

    Jänne, J; Morris, D R

    1984-01-01

    Several congeners of methylglyoxal bis(guanylhydrazone) were tested for their ability to inhibit eukaryotic putrescine-activated S-adenosylmethionine decarboxylase (EC 4.1.1.50) and intestinal diamine oxidase (EC 1.4.3.6). All the compounds tested, namely methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone), dimethylglyoxal bis(guanylhydrazone) and the di-N"-methyl derivative of methylglyoxal bis(guanylhydrazone), were strong inhibitors of both yeast and mouse liver adenosylmethionine decarboxylase activity in vitro. The enzyme from both sources was most powerfully inhibited by ethylglyoxal bis(guanylhydrazone). All the diguanidines likewise inhibited diamine oxidase activity in vitro. The maximum intracellular concentrations of the ethyl and dimethylated analogues achieved in activated lymphocytes were only about one-fifth of that of the parent compound. However, both derivatives appeared to utilize the polyamine-carrier system, as indicated by competition experiments with spermidine. PMID:6426466

  20. Inhibition of S-adenosylmethionine decarboxylase and diamine oxidase activities by analogues of methylglyoxal bis(guanylhydrazone) and their cellular uptake during lymphocyte activation.

    PubMed

    Jänne, J; Morris, D R

    1984-03-15

    Several congeners of methylglyoxal bis(guanylhydrazone) were tested for their ability to inhibit eukaryotic putrescine-activated S-adenosylmethionine decarboxylase (EC 4.1.1.50) and intestinal diamine oxidase (EC 1.4.3.6). All the compounds tested, namely methylglyoxal bis(guanylhydrazone), ethylglyoxal bis(guanylhydrazone), dimethylglyoxal bis(guanylhydrazone) and the di-N"-methyl derivative of methylglyoxal bis(guanylhydrazone), were strong inhibitors of both yeast and mouse liver adenosylmethionine decarboxylase activity in vitro. The enzyme from both sources was most powerfully inhibited by ethylglyoxal bis(guanylhydrazone). All the diguanidines likewise inhibited diamine oxidase activity in vitro. The maximum intracellular concentrations of the ethyl and dimethylated analogues achieved in activated lymphocytes were only about one-fifth of that of the parent compound. However, both derivatives appeared to utilize the polyamine-carrier system, as indicated by competition experiments with spermidine.

  1. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Asmis, Lars; Tanner, Felix C.; Center for Integrative Human Physiology, University of Zuerich, Zuerich

    2010-01-22

    Background: DMSO is routinely infused together with hematopoietic cells in patients undergoing myeloablative therapy and was recently found to inhibit smooth muscle cells proliferation and arterial thrombus formation in the mouse by preventing tissue factor (TF), a key activator of the coagulation cascade. This study was designed to investigate whether DMSO prevents platelet activation and thus, whether it may represent an interesting agent to be used on drug eluting stents. Methods and results: Human venous blood from healthy volunteers was collected in citrated tubes and platelet activation was studied by cone and platelet analyzer (CPA) and rapid-platelet-function-assay (RPFA). CPA analysismore » showed that DMSO-treated platelets exhibit a lower adherence in response to shear stress (-15.54 {+-} 0.9427%, n = 5, P < 0.0001 versus control). Additionally, aggregometry studies revealed that DMSO-treated, arachidonate-stimulated platelets had an increased lag phase (18.0% {+-} 4.031, n = 9, P = 0.0004 versus control) as well as a decreased maximal aggregation (-6.388 {+-} 2.212%, n = 6, P = 0.0162 versus control). Inhibitory action of DMSO could be rescued by exogenous thromboxane A2 and was mediated, at least in part, by COX-1 inhibition. Conclusions: Clinically relevant concentrations of DMSO impair platelet activation by a thromboxane A2-dependent, COX-1-mediated effect. This finding may be crucial for the previously reported anti-thrombotic property displayed by DMSO. Our findings support a role for DMSO as a novel drug to prevent not only proliferation, but also thrombotic complications of drug eluting stents.« less

  2. Inhibition of tumor cellular proteasome activity by triptolide extracted from the Chinese medicinal plant 'thunder god vine'.

    PubMed

    Lu, Li; Kanwar, Jyoti; Schmitt, Sara; Cui, Qiuzhi Cindy; Zhang, Chuanyin; Zhao, Cong; Dou, Q Ping

    2011-01-01

    The molecular mechanisms of triptolide responsible for its antitumor properties are not yet fully understood. The ubiquitin/proteasome system is an important pathway of protein degradation in cells. This study investigated whether triptolide may inhibit proteasomal activity and induce apoptosis in human cancer cells. In vitro proteasome inhibition was measured by incubation of a purified 20S proteasome with triptolide. Human breast and prostate cancer cell lines were also treated with different doses of triptolide for different times, followed by measurement of proteasome inhibition (levels of the chymotrypsin-like activity, ubiquitinated proteins and three well-known proteasome target proteins, p27, IκB-α and Bax) and apoptosis induction (caspase-3 activity and PARP cleavage). Triptolide did not inhibit the chymotrypsin-like activity of purified 20S proteasome. However, treatment of triptolide was able to cause decreased levels of cellular proteasomal chymotrypsin-like activity and accumulation of ubiquitinated proteins and three well-known proteasome target proteins in human breast and prostate cancer cells, associated with apoptosis induction. It is possible that at least one of metabolites of triptolide has proteasome-inhibitory activity.

  3. Preferential amino acid sequences in alumina-catalyzed peptide bond formation.

    PubMed

    Bujdák, J; Rode, B M

    2002-05-21

    The catalytic effect of activated alumina on amino acid condensation was investigated. The readiness of amino acids to form peptide sequences was estimated on the basis of the yield of dipeptides and was found to decrease in the order glycine (Gly), alanine (Ala), leucine (Leu), valine (Val), proline (Pro). For example, approximately 15% Gly was converted to the dipeptide (Gly(2)), 5% to cyclic anhydride (cyc(Gly(2))) and small amounts of tri- (Gly(3)) and tetrapeptide (Gly(4)) were formed after 28 days. On the other hand, only trace amounts of Pro(2) were formed from proline under the same conditions. Preferential formation of certain sequences was observed in the mixed reaction systems containing two amino acids. For example, almost ten times more Gly-Val than Val-Gly was formed in the Gly+Val reaction system. The preferred sequences can be explained on the basis of an inductive effect that side groups have on the nucleophilicity and electrophilicity, respectively, of the amino and carboxyl groups. A comparison with published data of amino acid reactions in other reaction systems revealed that the main trends of preferential sequence formation were the same as those described for the salt-induced peptide formation (SIPF) reaction. The results of this work and other previously published papers show that alumina and related mineral surfaces might have played a crucial role in the prebiotic formation of the first peptides on the primitive earth.

  4. Sphingosine kinase inhibition alleviates endothelial permeability induced by thrombin and activated neutrophils.

    PubMed

    Itagaki, Kiyoshi; Zhang, Qin; Hauser, Carl J

    2010-04-01

    Inflammation and microvascular thrombosis are interrelated causes of acute lung injury in the systemic inflammatory response syndrome. Neutrophils (polymorphonuclear neutrophil [PMN]) and endothelial cells (EC) activated by systemic inflammatory response syndrome interact to increase pulmonary vascular permeability, but the interactions between PMN and EC are difficult to study. Recently, we reported that sphingosine 1-phosphate is a second messenger eliciting store-operated calcium entry (SOCE) in response to inflammatory agonists in both PMN and EC. Store-operated calcium entry is therefore a target mechanism for the therapeutic modulation of inflammatory PMN-EC interactions. Here, we isolated, modeled, and studied the effects of pharmacologic SOCE inhibition using real-time systems to monitor EC permeability after exposure to activated PMN. We created systems to continuously assess permeability of human pulmonary artery endothelial cells and human microvascular endothelial cells from lung. Endothelial cells show increased permeability after challenge by activated PMN. Such permeability increases can be attenuated by exposure of the cocultures to sphingosine kinase (SK) inhibitors (SKI-2, N,N-dimethylsphingosine [DMS]) or Ca2+ entry inhibitors (Gd3+, MRS-1845). Human microvascular endothelial cells from lung pretreated with SKI-2 or DMS showed decreased permeability when later exposed to activated PMN. Likewise, when PMNs were activated with thapsigargin (TG) in the presence of SKI-2, DMS, Gd, or MRS-1845, their ability to cause EC permeability subsequently was reduced. SKI-2 also inhibited the activation of human pulmonary artery ECs by thrombin. These studies will provide a firm mechanistic foundation for understanding how systemic SOCE inhibition may be used to prevent acute lung injury in vivo.

  5. Natural amines inhibit activation of human plasmacytoid dendritic cells through CXCR4 engagement

    PubMed Central

    Smith, Nikaïa; Pietrancosta, Nicolas; Davidson, Sophia; Dutrieux, Jacques; Chauveau, Lise; Cutolo, Pasquale; Dy, Michel; Scott-Algara, Daniel; Manoury, Bénédicte; Zirafi, Onofrio; McCort-Tranchepain, Isabelle; Durroux, Thierry; Bachelerie, Françoise; Schwartz, Olivier; Münch, Jan; Wack, Andreas; Nisole, Sébastien; Herbeuval, Jean-Philippe

    2017-01-01

    Plasmacytoid dendritic cells (pDC) are specialized in secretion of type I interferon in response to pathogens. Here we show that natural monoamines and synthetic amines inhibit pDC activation by RNA viruses. Furthermore, a synthetic analogue of histamine reduces type I interferon production in a mouse model of influenza infection. We identify CXC chemokine receptor 4 (CXCR4) as a receptor used by amines to inhibit pDC. Our study establishes a functional link between natural amines and the innate immune system and identifies CXCR4 as a potential ‘on-off' switch of pDC activity with therapeutic potential. PMID:28181493

  6. Evaluation of enzymes inhibition activities of medicinal plant from Burkina Faso.

    PubMed

    Bangou, Mindiédiba Jean; Kiendrebeogo, Martin; Meda, Nâg-Tiero Roland; Coulibaly, Ahmed Yacouba; Compaoré, Moussa; Zeba, Boukaré; Millogo-Rasolodimby, Jeanne; Nacoulma, Odile Germaine

    2011-01-15

    The aim of the present study was to evaluate some enzymes inhibitory effects of 11 plant species belonging to 9 families from Burkina Faso. Methanolic extracts were used for their Glutathione-s-transferase (GST), Acetylcholinesterase (AChE), Carboxylesterase (CES) and Xanthine Oxidase (XO) inhibitory activities at final concentration of 100 microg mL(-1). The total phenolics, flavonoids and tannins were also determined spectrophotometrically using Folin-Ciocalteu, AlCl3 and ammonium citrate iron reagents, respectively. Among the 11 species tested, the best inhibitory percentages were found with Euphorbia hirta, Sclerocarya birrea and Scoparia dulcis (inhibition > 40%) followed by Annona senegalensis, Annona squamosa, Polygala arenaria and Ceratotheca sesamoides (inhibition > 25%). The best total phenolic and tannin contents were found with S. birrea with 56.10 mg GAE/100 mg extract and 47.75 mg TAE/100 mg extract, respectively. E hirta presented the higher total flavonoids (9.96 mg QE/100 mg extract). It's was found that Sclerocarya birrea has inhibited all enzymes at more than 30% and this activity is correlated to total tannins contents. Contrary to S. birrea, the enzymatic activities of E. hirta and S. dulcis are correlated to total flavonoids contents. Present findings suggest that the methanolic extracts of those plant species are potential inhibitors of GST, AChE, CES and XO and confirm their traditional uses in the treatment of mental disorders, gout, painful inflammations and cardiovascular diseases.

  7. Declustering of clustered preferential sampling for histogram and semivariogram inference

    USGS Publications Warehouse

    Olea, R.A.

    2007-01-01

    Measurements of attributes obtained more as a consequence of business ventures than sampling design frequently result in samplings that are preferential both in location and value, typically in the form of clusters along the pay. Preferential sampling requires preprocessing for the purpose of properly inferring characteristics of the parent population, such as the cumulative distribution and the semivariogram. Consideration of the distance to the nearest neighbor allows preparation of resampled sets that produce comparable results to those from previously proposed methods. Clustered sampling of size 140, taken from an exhaustive sampling, is employed to illustrate this approach. ?? International Association for Mathematical Geology 2007.

  8. Preferential extravasation and accumulation of liposomal vincristine in tumor comparing to normal tissue enhances antitumor activity.

    PubMed

    Shan, Siqing; Flowers, Clay; Peltz, Cathy D; Sweet, Heather; Maurer, Norbert; Kwon, Eun-Joo Gina; Krol, Ave; Yuan, Fan; Dewhirst, Mark W

    2006-08-01

    To quantitatively evaluate the extravasation, accumulation and selectivity to tumor tissues of liposomal vincristine (LV), dorsal skin-fold window chambers on athymic mice with or without LX-1, a human small cell lung cancer, xenograft implants and fluorescent intravital microscopy imaging were used. In vitro studies show that minimal loss of fluorescence marker DiI from liposomes occurs after 4 days of inoculation in murine plasma, and the release profiles of DiI-LV and LV were essentially the same with approximately 40% of the encapsulated vincristine sulfate (VCR) released after 26 h. Significantly faster extravasation of DiI-LV from tumor vessels was shown compared to non-tumor tissue after single dose i.v. administration. The relative interstitial amounts at 60 min (RIA(60)) for tumor and non-tumor tissues were 0.837+/-0.314 and 0.012+/-0.091, respectively (P=0.01). DiI-LV accumulation was significantly higher in tumor than in normal tissue, which continued beyond 48 h. Both DiI-LV and LV showed significant antitumor effects in window chambers and in flank tumors, compared with controls and VLS alone. The preferential extravasation of DiI-LV from tumor vasculature as well as its differential retention in tumor tissue provides the basis for the enhancement in antitumor activity of LV over VCR.

  9. Selective antibacterial activity of patchouli alcohol against Helicobacter pylori based on inhibition of urease.

    PubMed

    Yu, Xiao-Dan; Xie, Jian-Hui; Wang, Yong-Hong; Li, Yu-Cui; Mo, Zhi-Zhun; Zheng, Yi-Feng; Su, Ji-Yan; Liang, Ye-er; Liang, Jin-Zhi; Su, Zi-Ren; Huang, Ping

    2015-01-01

    The aim of this study is to evaluate the antibacterial activity and urease inhibitory effects of patchouli alcohol (PA), the bioactive ingredient isolated from Pogostemonis Herba, which has been widely used for the treatment of gastrointestinal disorders. The activities of PA against selected bacteria and fungi were determined by agar dilution method. It was demonstrated that PA exhibited selective antibacterial activity against Helicobacter pylori, without influencing the major normal gastrointestinal bacteria. Noticeably, the antibacterial activity of PA was superior to that of amoxicillin, with minimal inhibition concentration value of 78 µg/mL. On the other hand, PA inhibited ureases from H.pylori and jack bean in concentration-dependent fashion with IC50 values of 2.67 ± 0.79 mM and 2.99 ± 0.41 mM, respectively. Lineweaver-Burk plots indicated that the type of inhibition was non-competitive against H.pylori urease whereas uncompetitive against jack bean urease. Reactivation of PA-inactivated urease assay showed DL-dithiothreitol, the thiol reagent, synergistically inactivated urease with PA instead of enzymatic activity recovery. In conclusion, the selective H.pylori antibacterial activity along with urease inhibitory potential of PA could make it a possible drug candidate for the treatment of H.pylori infection. Copyright © 2014 John Wiley & Sons, Ltd.

  10. Preferential selection based on degree difference in the spatial prisoner's dilemma games

    NASA Astrophysics Data System (ADS)

    Huang, Changwei; Dai, Qionglin; Cheng, Hongyan; Li, Haihong

    2017-10-01

    Strategy evolution in spatial evolutionary games is generally implemented through imitation processes between individuals. In most previous studies, it is assumed that individuals pick up one of their neighbors randomly to learn from. However, by considering the heterogeneity of individuals' influence in the real society, preferential selection is more realistic. Here, we introduce a preferential selection mechanism based on degree difference into spatial prisoner's dilemma games on Erdös-Rényi networks and Barabási-Albert scale-free networks and investigate the effects of the preferential selection on cooperation. The results show that, when the individuals prefer to choose the neighbors who have small degree difference with themselves to imitate, cooperation is hurt by the preferential selection. In contrast, when the individuals prefer to choose those large degree difference neighbors to learn from, there exists optimal preference strength resulting in the maximal cooperation level no matter what the network structure is. In addition, we investigate the robustness of the results against variations of the noise, the average degree and the size of network in the model, and find that the qualitative features of the results are unchanged.

  11. Inhibition of EGFR Induces a c-MET Driven Stem Cell Population in Glioblastoma

    PubMed Central

    Jun, Hyun Jung; Bronson, Roderick T.; Charest, Al

    2015-01-01

    Glioblastoma multiforme (GBM) is the most lethal form of primary brain tumors, characterized by highly invasive and aggressive tumors that are resistant to all current therapeutic options. GBMs are highly heterogeneous in nature and contain a small but highly tumorigenic and self-renewing population of stem or initiating cells (Glioblastoma stem cells or GSCs). GSCs have been shown to contribute to tumor propagation and resistance to current therapeutic modalities. Recent studies of human GBMs have elucidated the genetic alterations common in these tumors, but much remains unknown about specific signaling pathways that regulate GSCs. Here we identify a distinct fraction of cells in a genetically engineered mouse model of EGFR-driven GBM that respond to anti-EGFR therapy by inducing high levels of c-MET expression. The MET positive cells displayed clonogenic potential and long-term self-renewal ability in vitro and are capable of differentiating into multiple lineages. The MET positive GBM cells are resistant to radiation and highly tumorigenic in vivo. Activation of MET signaling led to an increase in expression of the stemness transcriptional regulators Oct4, Nanog and Klf4. Pharmacological inhibition of MET activity in GSCs prevented the activation of Oct4, Nanog and Klf4 and potently abrogated stemness. Finally, the MET expressing cells were preferentially localized in perivascular regions of mouse tumors consistent with their function as GSCs. Together, our findings indicate that EGFR inhibition in GBM induces MET activation in GSCs, which is a functional requisite for GSCs activity and thus represents a promising therapeutic target. PMID:24115218

  12. Belinostat-induced apoptosis and growth inhibition in pancreatic cancer cells involve activation of TAK1-AMPK signaling axis

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, Bing, E-mail: wangbin69@yahoo.com; Wang, Xin-bao; Chen, Li-yu

    2013-07-19

    Highlights: •Belinostat activates AMPK in cultured pancreatic cancer cells. •Activation of AMPK is important for belinostat-induced cytotoxic effects. •ROS and TAK1 are involved in belinostat-induced AMPK activation. •AMPK activation mediates mTOR inhibition by belinostat. -- Abstract: Pancreatic cancer accounts for more than 250,000 deaths worldwide each year. Recent studies have shown that belinostat, a novel pan histone deacetylases inhibitor (HDACi) induces apoptosis and growth inhibition in pancreatic cancer cells. However, the underlying mechanisms are not fully understood. In the current study, we found that AMP-activated protein kinase (AMPK) activation was required for belinostat-induced apoptosis and anti-proliferation in PANC-1 pancreatic cancermore » cells. A significant AMPK activation was induced by belinostat in PANC-1 cells. Inhibition of AMPK by RNAi knockdown or dominant negative (DN) mutation significantly inhibited belinostat-induced apoptosis in PANC-1 cells. Reversely, AMPK activator AICAR and A-769662 exerted strong cytotoxicity in PANC-1 cells. Belinostat promoted reactive oxygen species (ROS) production in PANC-1 cells, increased ROS induced transforming growth factor-β-activating kinase 1 (TAK1)/AMPK association to activate AMPK. Meanwhile, anti-oxidants N-Acetyl-Cysteine (NAC) and MnTBAP as well as TAK1 shRNA knockdown suppressed belinostat-induced AMPK activation and PANC-1 cell apoptosis. In conclusion, we propose that belinostat-induced apoptosis and growth inhibition require the activation of ROS-TAK1-AMPK signaling axis in cultured pancreatic cancer cells.« less

  13. Inhibition of gap-junctional intercellular communication and activation of mitogen-activated protein kinases by cyanobacterial extracts--indications of novel tumor-promoting cyanotoxins?

    PubMed

    Bláha, Ludĕk; Babica, Pavel; Hilscherová, Klára; Upham, Brad L

    2010-01-01

    Toxicity and liver tumor promotion of cyanotoxins microcystins have been extensively studied. However, recent studies document that other metabolites present in the complex cyanobacterial water blooms may also have adverse health effects. In this study we used rat liver epithelial stem-like cells (WB-F344) to examine the effects of cyanobacterial extracts on two established markers of tumor promotion, inhibition of gap-junctional intercellular communication (GJIC) and activation of mitogen-activated protein kinases (MAPKs) - ERK1/2. Extracts of cyanobacteria (laboratory cultures of Microcystis aeruginosa and Aphanizomenon flos-aquae and water blooms dominated by these species) inhibited GJIC and activated MAPKs in a dose-dependent manner (effective concentrations ranging 0.5-5mgd.w./mL). Effects were independent of the microcystin content and the strongest responses were elicited by the extracts of Aphanizomenon sp. Neither pure microcystin-LR nor cylindrospermopsin inhibited GJIC or activated MAPKs. Modulations of GJIC and MAPKs appeared to be specific to cyanobacterial extracts since extracts from green alga Chlamydomonas reinhardtii, heterotrophic bacterium Klebsiella terrigena, and isolated bacterial lipopolysaccharides had no comparable effects. Our study provides the first evidence on the existence of unknown cyanobacterial toxic metabolites that affect in vitro biomarkers of tumor promotion, i.e. inhibition of GJIC and activation of MAPKs.

  14. Fenofibrate inhibits aldosterone-induced apoptosis in adult rat ventricular myocytes via stress-activated kinase-dependent mechanisms

    PubMed Central

    De Silva, Deepa S.; Wilson, Richard M.; Hutchinson, Christoph; Ip, Peter C.; Garcia, Anthony G.; Lancel, Steve; Ito, Masa; Pimentel, David R.; Sam, Flora

    2009-01-01

    Aldosterone induces extracellular signal-regulated kinase (ERK)-dependent cardiac remodeling. Fenofibrate improves cardiac remodeling in adult rat ventricular myocytes (ARVM) partly via inhibition of aldosterone-induced ERK1/2 phosphorylation and inhibition of matrix metalloproteinases. We sought to determine whether aldosterone caused apoptosis in cultured ARVM and whether fenofibrate ameliorated the apoptosis. Aldosterone (1 μM) induced apoptosis by increasing terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive nuclei in ARVM. Spironolactone (100 nM), an aldosterone receptor antagonist, but not RU-486, a glucocorticoid receptor, inhibited aldosterone-mediated apoptosis, indicating that the mineralocorticoid receptor (MR) plays a role. SP-600125 (3 μM)—a selective inhibitor of c-Jun NH2-terminal kinase (JNK)—inhibited aldosterone-induced apoptosis in ARVM. Although aldosterone increased the expression of both stress-activated protein kinases, pretreatment with fenofibrate (10 μM) decreased aldosterone-mediated apoptosis by inhibiting only JNK phosphorylation and the aldosterone-induced increases in Bax, p53, and cleaved caspase-3 and decreases in Bcl-2 protein expression in ARVM. In vivo studies demonstrated that chronic fenofibrate (100 mg·kg body wt−1·day−1) inhibited myocardial Bax and increased Bcl-2 expression in aldosterone-induced cardiac hypertrophy. Similarly, eplerenone, a selective MR inhibitor, used in chronic pressure-overload ascending aortic constriction inhibited myocardial Bax expression but had no effect on Bcl-2 expression. Therefore, involvement of JNK MAPK-dependent mitochondrial death pathway mediates ARVM aldosterone-induced apoptosis and is inhibited by fenofibrate, a peroxisome proliferator-activated receptor (PPAR)α ligand. Fenofibrate mediates beneficial effects in cardiac remodeling by inhibiting programmed cell death and the stress-activated kinases. PMID:19395558

  15. The WT hemochromatosis protein HFE inhibits CD8⁺ T-lymphocyte activation.

    PubMed

    Reuben, Alexandre; Phénix, Mikaël; Santos, Manuela M; Lapointe, Réjean

    2014-06-01

    MHC class I (MHC I) antigen presentation is a ubiquitous process by which cells present endogenous proteins to CD8(+) T lymphocytes during immune surveillance and response. Hereditary hemochromatosis protein, HFE, is involved in cellular iron uptake but, while structurally homologous to MHC I, is unable to bind peptides. However, increasing evidence suggests a role for HFE in the immune system. Here, we investigated the impact of HFE on CD8(+) T-lymphocyte activation. Using transient HFE transfection assays in a model of APCs, we show that WT HFE (HFEWT ), but not C282Y-mutated HFE, inhibits secretion of MIP-1β from antigen-specific CD8(+) T lymphocytes. HFEWT expression also resulted in major decreases in CD8(+) T-lymphocyte activation as measured by 4-1BB expression. We further demonstrate that inhibition of CD8(+) T-lymphocyte activation was independent of MHC I surface levels, β2-m competition, HFE interaction with transferrin receptor, antigen origin, or epitope affinity. Finally, we identified the α1-2 domains of HFEWT as being responsible for inhibiting CD8(+) T-lymphocyte activation. Our data imply a new role for HFEWT in altering CD8(+) T-lymphocyte reactivity, which could modulate antigen immunogenicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Selective Inhibition of FOXO1 Activator/Repressor Balance Modulates Hepatic Glucose Handling.

    PubMed

    Langlet, Fanny; Haeusler, Rebecca A; Lindén, Daniel; Ericson, Elke; Norris, Tyrrell; Johansson, Anders; Cook, Joshua R; Aizawa, Kumiko; Wang, Ling; Buettner, Christoph; Accili, Domenico

    2017-11-02

    Insulin resistance is a hallmark of diabetes and an unmet clinical need. Insulin inhibits hepatic glucose production and promotes lipogenesis by suppressing FOXO1-dependent activation of G6pase and inhibition of glucokinase, respectively. The tight coupling of these events poses a dual conundrum: mechanistically, as the FOXO1 corepressor of glucokinase is unknown, and clinically, as inhibition of glucose production is predicted to increase lipogenesis. Here, we report that SIN3A is the insulin-sensitive FOXO1 corepressor of glucokinase. Genetic ablation of SIN3A abolishes nutrient regulation of glucokinase without affecting other FOXO1 target genes and lowers glycemia without concurrent steatosis. To extend this work, we executed a small-molecule screen and discovered selective inhibitors of FOXO-dependent glucose production devoid of lipogenic activity in hepatocytes. In addition to identifying a novel mode of insulin action, these data raise the possibility of developing selective modulators of unliganded transcription factors to dial out adverse effects of insulin sensitizers. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. GIV/Girdin activates Gαi and inhibits Gαs via the same motif

    PubMed Central

    Gupta, Vijay; Bhandari, Deepali; Leyme, Anthony; Aznar, Nicolas; Midde, Krishna K.; Lo, I-Chung; Ear, Jason; Niesman, Ingrid; López-Sánchez, Inmaculada; Blanco-Canosa, Juan Bautista; von Zastrow, Mark; Garcia-Marcos, Mikel; Farquhar, Marilyn G.; Ghosh, Pradipta

    2016-01-01

    We previously showed that guanine nucleotide-binding (G) protein α subunit (Gα)-interacting vesicle-associated protein (GIV), a guanine-nucleotide exchange factor (GEF), transactivates Gα activity-inhibiting polypeptide 1 (Gαi) proteins in response to growth factors, such as EGF, using a short C-terminal motif. Subsequent work demonstrated that GIV also binds Gαs and that inactive Gαs promotes maturation of endosomes and shuts down mitogenic MAPK–ERK1/2 signals from endosomes. However, the mechanism and consequences of dual coupling of GIV to two G proteins, Gαi and Gαs, remained unknown. Here we report that GIV is a bifunctional modulator of G proteins; it serves as a guanine nucleotide dissociation inhibitor (GDI) for Gαs using the same motif that allows it to serve as a GEF for Gαi. Upon EGF stimulation, GIV modulates Gαi and Gαs sequentially: first, a key phosphomodification favors the assembly of GIV–Gαi complexes and activates GIV’s GEF function; then a second phosphomodification terminates GIV’s GEF function, triggers the assembly of GIV–Gαs complexes, and activates GIV’s GDI function. By comparing WT and GIV mutants, we demonstrate that GIV inhibits Gαs activity in cells responding to EGF. Consequently, the cAMP→PKA→cAMP response element-binding protein signaling axis is inhibited, the transit time of EGF receptor through early endosomes are accelerated, mitogenic MAPK–ERK1/2 signals are rapidly terminated, and proliferation is suppressed. These insights define a paradigm in G-protein signaling in which a pleiotropically acting modulator uses the same motif both to activate and to inhibit G proteins. Our findings also illuminate how such modulation of two opposing Gα proteins integrates downstream signals and cellular responses. PMID:27621449

  18. Inhibition mechanism of P-glycoprotein mediated efflux by mPEG-PLA and influence of PLA chain length on P-glycoprotein inhibition activity.

    PubMed

    Li, Wenjing; Li, Xinru; Gao, Yajie; Zhou, Yanxia; Ma, Shujin; Zhao, Yong; Li, Jinwen; Liu, Yan; Wang, Xinglin; Yin, Dongdong

    2014-01-06

    The present study aimed to investigate the effect of monomethoxy poly(ethylene glycol)-block-poly(D,L-lactic acid) (mPEG-PLA) on the activity of P-glycoprotein (P-gp) in Caco-2 cells and further unravel the relationship between PLA chain length in mPEG-PLA and influence on P-gp efflux and the action mechanism. The transport results of rhodamine 123 (R123) across Caco-2 cell monolayers suggested that mPEG-PLA unimers were responsible for its P-gp inhibitory effect. Furthermore, transport studies of R123 revealed that the inhibitory potential of P-gp efflux by mPEG-PLA analogues was strongly correlated with their structural features and showed that the hydrophilic mPEG-PLA copolymers with an intermediate PLA chain length and 10.20 of hydrophilic-lipophilic balance were more effective at inhibiting P-gp efflux in Caco-2 cells. The fluorescence polarization measurement results ruled out the plasma membrane fluidization as a contributor for inhibition of P-gp by mPEG-PLA. Concurrently, mPEG-PLA inhibited neither basal P-gp ATPase (ATP is adenosine triphosphate) activity nor substrate stimulated P-gp ATPase activity, suggesting that mPEG-PLA seemed not to be a substrate of P-gp and a competitive inhibitor. No evident alteration in P-gp surface level was detected by flow cytometry upon exposure of the cells to mPEG-PLA. The depletion of intracellular ATP, which was likely to be a result of partial inhibition of cellular metabolism, was directly correlated with inhibitory potential for P-gp mediated efflux by mPEG-PLA analogues. Hence, intracellular ATP-depletion appeared to be possible explanation to the inhibition mechanism of P-gp by mPEG-PLA. Taken together, the establishment of a relationship between PLA chain length and impact on P-gp efflux activity and interpretation of action mechanism of mPEG-PLA on P-gp are of fundamental importance and will facilitate future development of mPEG-PLA in the drug delivery area.

  19. Short-ranged memory model with preferential growth

    NASA Astrophysics Data System (ADS)

    Schaigorodsky, Ana L.; Perotti, Juan I.; Almeira, Nahuel; Billoni, Orlando V.

    2018-02-01

    In this work we introduce a variant of the Yule-Simon model for preferential growth by incorporating a finite kernel to model the effects of bounded memory. We characterize the properties of the model combining analytical arguments with extensive numerical simulations. In particular, we analyze the lifetime and popularity distributions by mapping the model dynamics to corresponding Markov chains and branching processes, respectively. These distributions follow power laws with well-defined exponents that are within the range of the empirical data reported in ecologies. Interestingly, by varying the innovation rate, this simple out-of-equilibrium model exhibits many of the characteristics of a continuous phase transition and, around the critical point, it generates time series with power-law popularity, lifetime and interevent time distributions, and nontrivial temporal correlations, such as a bursty dynamics in analogy with the activity of solar flares. Our results suggest that an appropriate balance between innovation and oblivion rates could provide an explanatory framework for many of the properties commonly observed in many complex systems.

  20. Short-ranged memory model with preferential growth.

    PubMed

    Schaigorodsky, Ana L; Perotti, Juan I; Almeira, Nahuel; Billoni, Orlando V

    2018-02-01

    In this work we introduce a variant of the Yule-Simon model for preferential growth by incorporating a finite kernel to model the effects of bounded memory. We characterize the properties of the model combining analytical arguments with extensive numerical simulations. In particular, we analyze the lifetime and popularity distributions by mapping the model dynamics to corresponding Markov chains and branching processes, respectively. These distributions follow power laws with well-defined exponents that are within the range of the empirical data reported in ecologies. Interestingly, by varying the innovation rate, this simple out-of-equilibrium model exhibits many of the characteristics of a continuous phase transition and, around the critical point, it generates time series with power-law popularity, lifetime and interevent time distributions, and nontrivial temporal correlations, such as a bursty dynamics in analogy with the activity of solar flares. Our results suggest that an appropriate balance between innovation and oblivion rates could provide an explanatory framework for many of the properties commonly observed in many complex systems.

  1. Diosgenin inhibits superoxide generation in FMLP-activated mouse neutrophils via multiple pathways.

    PubMed

    Lin, Y; Jia, R; Liu, Y; Gao, Y; Zeng, X; Kou, J; Yu, B

    2014-12-01

    Diosgenin possesses anti-inflammatory and anticancer properties. Activated neutrophils produce high concentrations of the superoxide anion which is involved in the pathophysiology of inflammation-related diseases and cancer. In the present study, the inhibitory effect and possible mechanisms of diosgenin on superoxide generation were investigated in mouse bone marrow neutrophils. Diosgenin potently and concentration-dependently inhibited the extracellular and intracellular superoxide anion generation in Formyl-Met-Leu-Phe (FMLP)- activated neutrophils, with IC50 values of 0.50 ± 0.08 μM and 0.66 ± 0.13 μM, respectively. Such inhibition was not mediated by scavenging the superoxide anion or by a cytotoxic effect. Diosgenin inhibited the phosphorylation of p47phox and membrane translocation of p47phox and p67phox, and thus blocking the assembly of nicotinamide adenine dinucleotide phosphate oxidase. Moreover, cellular cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) expression were also effectively increased by diosgenin. It attenuated FMLP-induced increase of phosphorylation of cytosolic phospholipase A (cPLA2), p21-activated kinase (PAK), Akt, p38 mitogen-activated protein kinase (p38MAPK), extracellular signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK). Our data indicate that diosgenin exhibits inhibitory effects on superoxide anion production through the blockade of cAMP, PKA, cPLA2, PAK, Akt and MAPKs signaling pathways. The results may explain the clinical implications of diosgenin in the treatment of inflammation-related disorders.

  2. Inhibition of the activity of cytotoxic murine T lymphocytes by antibodies to idiotypic determinants.

    PubMed Central

    Rabinowitz, R; Schlesinger, M

    1980-01-01

    The nature of the receptors on the surface of cytotoxic T lymphocytes (CTL), which enable these cells to recognize antigens on allogeneic targets, is still a matter of controversy. In the present study various mouse alloantisera were tested for their capacity to inhibit, in the absence of complement, the cytotoxic activity of sensitized peritoneal T lymphocytes. The only antiserum which, even after heat inactivation, consistently inhibited cytotoxic T lymphocytes was an antiserum elicited in (C3H X C57B1/6)F1 mice by immunization with AKR/Cum thymus cells. The serum inhibited the cytotoxic reaction of either AKR/J or AKR/Cum CTL on EL-4 target cells but had no inhibitory activity on the cytotoxic reaction of AKR/J cells against P-815 target cells. Thus the inhibitory activity of the serum could not be attributed to antibodies against Ly-3 determinants present in the serum. This conclusion was strengthened by the finding that the inhibitory activity of the serum could be removed by absorption, not only with AKR/J thymus cells but also with AKR/J bone-marrow cells, a procedure which did not affect the titre of Ly-3 antibodies. The serum failed to exert any inhibition on cytotoxic T lymphocytes of BALB/c and C3H mice reacting against EL-4 target cells, indicating that the inhibitory activity of the antiserum did not result from contamination by antibodies against C57B1 antigenic determinants. It was concluded that the inhibitory activity of the antiserum resulted from the presence of antibodies against idiotypic determinants expressed on AKR/Cum thymus cells reacting against the hybrid hosts. It seems, therefore, that idiotypic determinants expressed on the surface of cytotoxic T lymphocytes may be directly involved in their cytotoxic activity. PMID:6155324

  3. Inhibition of the active lymph pump by flow in rat mesenteric lymphatics and thoracic duct

    NASA Technical Reports Server (NTRS)

    Gashev, Anatoliy A.; Davis, Michael J.; Zawieja, David C.; Delp, M. D. (Principal Investigator)

    2002-01-01

    There are only a few reports of the influence of imposed flow on an active lymph pump under conditions of controlled intraluminal pressure. Thus, the mechanisms are not clearly defined. Rat mesenteric lymphatics and thoracic ducts were isolated, cannulated and pressurized. Input and output pressures were adjusted to impose various flows. Lymphatic systolic and diastolic diameters were measured and used to determine contraction frequency and pump flow indices. Imposed flow inhibited the active lymph pump in both mesenteric lymphatics and in the thoracic duct. The active pump of the thoracic duct appeared more sensitive to flow than did the active pump of the mesenteric lymphatics. Imposed flow reduced the frequency and amplitude of the contractions and accordingly the active pump flow. Flow-induced inhibition of the active lymph pump followed two temporal patterns. The first pattern was a rapidly developing inhibition of contraction frequency. Upon imposition of flow, the contraction frequency immediately fell and then partially recovered over time during continued flow. This effect was dependent on the magnitude of imposed flow, but did not depend on the direction of flow. The effect also depended upon the rate of change in the direction of flow. The second pattern was a slowly developing reduction of the amplitude of the lymphatic contractions, which increased over time during continued flow. The inhibition of contraction amplitude was dependent on the direction of the imposed flow, but independent of the magnitude of flow. Nitric oxide was partly but not completely responsible for the influence of flow on the mesenteric lymph pump. Exposure to NO mimicked the effects of flow, and inhibition of the NO synthase by N (G)-monomethyl-L-arginine attenuated but did not completely abolish the effects of flow.

  4. Progesterone Directly and Rapidly Inhibits GnRH Neuronal Activity via Progesterone Receptor Membrane Component 1

    PubMed Central

    Bashour, Nicholas Michael

    2012-01-01

    GnRH neurons are essential for reproduction, being an integral component of the hypothalamic-pituitary-gonadal axis. Progesterone (P4), a steroid hormone, modulates reproductive behavior and is associated with rapid changes in GnRH secretion. However, a direct action of P4 on GnRH neurons has not been previously described. Receptors in the progestin/adipoQ receptor family (PAQR), as well as progesterone receptor membrane component 1 (PgRMC1) and its partner serpin peptidase inhibitor, clade E (nexin, plasminogen activator inhibitor type 1) mRNA binding protein 1 (SERBP1), have been shown to mediate rapid progestin actions in various tissues, including the brain. This study shows that PgRMC1 and SERBP1, but not PAQR, are expressed in prenatal GnRH neurons. Expression of PgRMC1 and SERBP1 was verified in adult mouse GnRH neurons. To investigate the effect of P4 on GnRH neuronal activity, calcium imaging was used on primary GnRH neurons maintained in explants. Application of P4 significantly decreased the activity of GnRH neurons, independent of secretion of gamma-aminobutyric acidergic and glutamatergic input, suggesting a direct action of P4 on GnRH neurons. Inhibition was not blocked by RU486, an antagonist of the classic nuclear P4 receptor. Inhibition was also maintained after uncoupling of the inhibitory regulative G protein (Gi/o), the signal transduction pathway used by PAQR. However, AG-205, a PgRMC1 ligand and inhibitor, blocked the rapid P4-mediated inhibition, and inhibition of protein kinase G, thought to be activated downstream of PgRMC1, also blocked the inhibitory activity of P4. These data show for the first time that P4 can act directly on GnRH neurons through PgRMC1 to inhibit neuronal activity. PMID:22822163

  5. Comparative analysis of topoisomerase IB inhibition and DNA intercalation by flavonoids and similar compounds: structural determinates of activity

    PubMed Central

    2004-01-01

    Flavonoids and other polyphenolic compounds have been shown to inhibit human topoisomerase IB (topo I) through both inhibition of relaxation activity and through stabilization of the cleavable complex (poisoning). Some flavonoids have also been shown to intercalate DNA, and an association of topoisomerase inhibition with intercalation has been noted. We surveyed 34 polyphenolic compounds, primarily flavonoid glycones and aglycones, for their ability to inhibit topo I and to intercalate DNA using an in vitro gel electrophoresis method. We show that the most potent topo I poisons are the flavones and flavonols, and that these generally, but not always, are found to be DNA intercalators. There was no clear correlation, however, of topo-I-poisoning activity with the degree of DNA unwinding. Surprisingly, both DNA intercalation and topo I poisoning were shown to occur with some flavone glycones, including the C-glycosylflavone orientin. Inhibition of relaxation activity by flavonoids was found to be difficult to quantify and was most likely to be due to non-specific inhibition through flavonoid aggregation. As part of a structure–activity analysis, we also investigated the acid–base chemistry of flavonoids and determined that many flavonoids show acid–base activity with a pKa in the physiological pH region. For this reason, subtle pH changes can have significant effects on solution activity of flavonoids and their concomitant biological activity. In addition, these effects may be complicated by pH-dependent aggregation and oxidative degradation. Finally, we develop a simple model for the intercalation of flavonoids into DNA and discuss possible consequences of intercalation and topoisomerase inhibition on a number of cellular processes. PMID:15312049

  6. TRANSCRIPTIONAL INHIBITION OF INTERLEUKIN-12 PROMOTER ACTIVITY IN LEISHMANIA SPP.-INFECTED MACROPHAGES

    PubMed Central

    Jayakumar, Asha; Widenmaier, Robyn; Ma, Xiaojing; McDowell, Mary Ann

    2009-01-01

    To establish and persist within a host, Leishmania spp. parasites delay the onset of cell-mediated immunity by suppressing interleukin-12 (IL-12) production from host macrophages. Although it is established that Leishmania spp.-infected macrophages have impaired IL-12 production, the mechanisms that account for this suppression remain to be completely elucidated. Using a luciferase reporter assay assessing IL-12 transcription, we report here that Leishmania major, Leishmania donovani, and Leishmania chagasi inhibit IL-12 transcription in response to interferon-gamma, lipopolysaccharide, and CD40 ligand and that Leishmania spp. lipophosphoglycan, phosphoglycans, and major surface protein are not necessary for inhibition. In addition, all the Leishmania spp. strains and life-cycle stages tested inhibited IL-12 promoter activity. Our data further reveal that autocrine-acting host factors play no role in the inhibitory response and that phagocytosis signaling is necessary for inhibition of IL-12. PMID:18372625

  7. Mechanism study of endothelial protection and inhibits platelet activation of low molecular weight fucoidan from Laminaria japonica

    NASA Astrophysics Data System (ADS)

    Chen, Anjin; Zhang, Fang; Shi, Jie; Zhao, Xue; Yan, Meixing

    2016-10-01

    Several studies have indicated that fucoidan fractions with low molecular weight and different sulfate content from Laminaria japonica could inhibit the activation of platelets directly by reducing the platelet aggregation. To explore the direct effect of LMW fucoidan on the platelet system furthermore and examine the possible mechanism, the endothelial protection and inhibits platelet activation effects of two LMW fucoidan were investigated. In the present study, Endothelial injury model of rats was made by injection of adrenaline (0.4 mg kg-1) and human umbilical vein endothelial cells were cultured. vWF level was be investigated in vivo and in vitro as an important index of endothelial injury. LMW fucoidan could significantly reduce vWF level in vascular endothelial injury rats and also significantly reduce vWF level in vitro. The number of EMPs was be detected as another important index of endothelial injury. The results showed that LMW fucoidan reduced EMPs stimulated by tumor necrosis factor. In this study, it was found that by inhibiting platelet adhesion, LMW fucoidan played a role in anti-thrombosis and the specific mechanism of action is to inhibit the flow of extracellular Ca2+. All in a word, LMW fucoidan could inhibit the activation of platelets indirectly by reducing the concentration of EMPs and vWF, at the same time; LMW fucoidan inhibited the activation of platelets directly by inhibiting the flow of extracellular Ca2+.

  8. Chemical Inhibition of a Subset of Arabidopsis thaliana GSK3-like Kinases Activates Brassinosteroid Signaling

    PubMed Central

    De Rybel, Bert; Audenaert, Dominique; Vert, Grégory; Rozhon, Wilfried; Mayerhofer, Juliane; Peelman, Frank; Coutuer, Silvie; Denayer, Tinneke; Jansen, Leentje; Nguyen, Long; Vanhoutte, Isabelle; Beemster, Gerrit T.S.; Vleminckx, Kris; Jonak, Claudia; Chory, Joanne; Inzé, Dirk; Russinova, Eugenia; Beeckman, Tom

    2016-01-01

    SUMMARY Glycogen synthase kinase 3 (GSK3) is a key regulator in signaling pathways in both animals and plants. Three Arabidopsis thaliana GSK3s are shown to be related to brassinosteroid (BR) signaling. In a phenotype-based compound screen we identified bikinin, a small molecule that activates BR signaling downstream of the BR receptor. Bikinin directly binds the GSK3 BIN2 and acts as an ATP competitor. Furthermore, bikinin inhibits the activity of six other Arabidopsis GSK3s. Genome-wide transcript analyses demonstrate that simultaneous inhibition of seven GSK3s is sufficient to activate BR responses. Our data suggest that GSK3 inhibition is the sole activation mode of BR signaling and argues against GSK3-independent BR responses in Arabidopsis. The opportunity to generate multiple and conditional knockouts in key regulators in the BR signaling pathway by bikinin represents a useful tool to further unravel regulatory mechanisms. PMID:19549598

  9. Investigating preferential flow processes in soils using anisotropy in electrical resistivity

    NASA Astrophysics Data System (ADS)

    Al-Hazaimay, S.; Huisman, J. A.; Zimmermann, E.; Kemna, A.; Vereecken, H.

    2012-12-01

    Macropores occupy a small volume fraction of the pore space in the vadose zone. Water and solutes can quickly bypass the vadose zone through these macropores in a process known as macropore preferential flow. In the last few decades, many efforts were made to improve understanding the macropore preferential flow processes because of their importance in transporting agrochemicals and contaminants to the groundwater. Unfortunately, very few measurement methods provide insights into these preferential flow processes. In this context, the objective of this study is to evaluate whether anisotropy in electrical resistivity can be used to identify the existence of flow in macropores and perhaps even to characterize the exchange between macropores and bulk soil. In a first step, infiltration into a soil column with an artificial macropore was simulated using the HYDRUS software package that solves the pseudo three-dimensional axisymmetric Richards equation. The simulated temporal development of the resistivity anisotropy was obtained by solving the Poisson equation in MATLAB after converting the simulated water content distributions to electrical resistivity distributions. At the beginning of the simulation, a small anisotropy ratio was simulated because of the presence of the empty ('deactivated') macropore in the moist matrix. As soon as the infiltration process started, macropore flow occurred and both the horizontal and vertical resistivity decreased strongly. However, the vertical and horizontal resistivity reacted differently because of the presence of the conductive ('activated') macropore, which led to anisotropy in the resistivity. As soon as infiltration into the macropore stopped, water re-distributed from the macropore to the matrix domain and contrasts in electrical resistivity decreased within the column. To verify the simulation results in the laboratory, we measured the temporal dynamics of the anisotropy in resistivity during water infiltration into a soil

  10. Synthesis of Cubic-Shaped Pt Particles with (100) Preferential Orientation by a Quick, One-Step and Clean Electrochemical Method.

    PubMed

    Liu, Jie; Fan, Xiayue; Liu, Xiaorui; Song, Zhishuang; Deng, Yida; Han, Xiaopeng; Hu, Wenbin; Zhong, Cheng

    2017-06-07

    A new approach has been developed for in situ preparing cubic-shaped Pt particles with (100) preferential orientation on the surface of the conductive support by using a quick, one-step, and clean electrochemical method with periodic square-wave potential. The whole electrochemical deposition process is very quick (only 6 min is required to produce cubic Pt particles), without the use of particular capping agents. The shape and the surface structure of deposited Pt particles can be controlled by the lower and upper potential limits of the square-wave potential. For a frequency of 5 Hz and an upper potential limit of 1.0 V (vs saturated calomel electrode), as the lower potential limit decreases to the H adsorption potential region, the Pt deposits are changed from nearly spherical particles to cubic-shaped (100)-oriented Pt particles. High-resolution transmission electron microscopy and selected-area electron diffraction reveal that the formed cubic Pt particles are single-crystalline and enclosed by (100) facets. Cubic Pt particles exhibit characteristic H adsorption/desorption peaks corresponding to the (100) preferential orientation. Ge irreversible adsorption indicates that the fraction of wide Pt(100) surface domains is 47.8%. The electrocatalytic activities of different Pt particles are investigated by ammonia electro-oxidation, which is particularly sensitive to the amount of Pt(100) sites, especially larger (100) domains. The specific activity of cubic Pt particles is 3.6 times as high as that of polycrystalline spherical Pt particles, again confirming the (100) preferential orientation of Pt cubes. The formation of cubic-shaped Pt particles is related with the preferential electrochemical deposition and dissolution processes of Pt, which are coupled with the periodic desorption and adsorption processes of O-containing species and H adatoms.

  11. Monoclonal antibodies against the native urease of Helicobacter pylori: synergistic inhibition of urease activity by monoclonal antibody combinations.

    PubMed Central

    Nagata, K; Mizuta, T; Tonokatu, Y; Fukuda, Y; Okamura, H; Hayashi, T; Shimoyama, T; Tamura, T

    1992-01-01

    Monoclonal antibodies (MAbs) against the native urease of Helicobacter pylori NCTC 11637 were found to clearly inhibit the urease activity. Interestingly, synergistic inhibition by two MAbs recognizing different subunits was also observed. Ten MAbs were produced and classified as two isotypes of the immunoglobulin G (IgG) subclass, IgG1, and IgG2a. Western blot (immunoblot) analysis using sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that five MAbs recognized the large subunit and the other five recognized the small subunit of the urease. Among the MAbs, L2 and S2, which recognized the large and the small subunits, respectively, were also able to inhibit the urease activity of clinical isolates from H. pylori-infected patients. The combination of L2 and S2 led to augmented synergistic inhibition. L2, but not S2, could also inhibit the urease activity from Helicobacter mustelae; enzyme-linked immunosorbent assay and Western blot analysis showed that L2 cross-reacted with this urease. These results suggested that the epitope recognized by L2 had a structure common to both Helicobacter species and may be involved in the active site of the urease. In contrast to the MAbs, a polyclonal antibody in sera from mice immunized with H. pylori urease did not have the ability to inhibit H. pylori urease activity. However, the polyclonal antibody retained the ability to abolish the inhibitory action of these MAbs. Moreover, other MAbs which could not inhibit H. pylori urease activity also abolished the inhibitory action. Images PMID:1383158

  12. Inhibition of venom serine proteinase and metalloproteinase activities by Renealmia alpinia (Zingiberaceae) extracts: comparison of wild and in vitro propagated plants.

    PubMed

    Patiño, Arley Camilo; Benjumea, Dora María; Pereañez, Jaime Andrés

    2013-09-16

    The plant Renealmia alpinia has been used in folk medicine to treat snakebites in the northwest region of Colombia. In addition, it has been shown to neutralize edema-forming, hemorrhagic, lethal, and defibrin(ogen)ating activities of Bothrops asper venom. In this work, extracts of Renealmia alpinia obtained by micropropagation (in vitro) and from specimens collected in the wild were tested and compared in their capacity to inhibit enzymatic and toxic activities of a snake venom metalloproteinase isolated from Bothrops atrox (Batx-I) venom and a serine proteinase (Cdc SII) from Crotalus durissus cumanensis venom. We have investigated the inhibition capacity of Renealmia alpinia extracts on enzymatic and toxic actions of isolated toxins, a metalloproteinase and a serine proteinase. The protocols investigated included inhibition of proteolytic activity on azocasein, inhibition of proteolytic activity on fibrinogen, inhibition of pro-coagulant activity, inhibition of hemorrhagic activity and inhibition of edema-forming activity. Colorimetric assays detected the presence of terpenoids, flavonoids, tannins and coumarins in Renealmia alpinia extracts. Renealmia alpinia extracts inhibited the enzymatic, hemorrhagic and fibrinogenolytic activities of Batx-I. Extracts also inhibited coagulant, defibrin(ogen)ating and edema-forming activities of Cdc SII. Results highlight that Renealmia alpinia in vitro extract displayed comparable inhibitory capacity on venom proteinases that Renealmia alpinia wild extract. No alteration was observed in the electrophoretic pattern of venom proteinases after incubation with Renealmia alpinia extracts, thus excluding proteolytic degradation or protein denaturation/precipitation as a mechanism of inhibition. Our results showed that Renealmia alpinia wild and in vitro extracts contain compounds that neutralize metallo- and serine proteinases present in snake venoms. The mechanism of inhibition is not related to proteolytic degradation of the

  13. Crystal structure, phytochemical study and enzyme inhibition activity of Ajaconine and Delectinine

    NASA Astrophysics Data System (ADS)

    Ahmad, Shujaat; Ahmad, Hanif; Khan, Hidayat Ullah; Shahzad, Adnan; Khan, Ezzat; Ali Shah, Syed Adnan; Ali, Mumtaz; Wadud, Abdul; Ghufran, Mehreen; Naz, Humera; Ahmad, Manzoor

    2016-11-01

    The Crystal structure, comparative DFT study and phytochemical investigation of atisine type C-20 diterpenoid alkaloid ajaconine (1) and lycoctonine type C-19 diterpenoid alkaloid delectinine (2) is reported here. These compounds were isolated from Delphinium chitralense. Both the natural products 1 and 2 crystallize in orthorhombic crystal system with identical space group of P212121. The geometric parameters of both compounds were calculated with the help of DFT using B3LYP/6-31+G (p) basis set and HOMO-LUMO energies, optimized band gaps, global hardness, ionization potential, electron affinity and global electrophilicity are calculated. The compounds 1 and 2 were screened for acetyl cholinesterase and butyryl cholinesterase inhibition activities in a dose dependent manner followed by molecular docking to explore the possible inhibitory mechanism of ajaconine (1) and delectinine (2). The IC50 values of tested compounds against AChE were observed as 12.61 μM (compound 1) and 5.04 μM (compound 2). The same experiments were performed for inhibition of BChE and IC50 was observed to be 10.18 μM (1) and 9.21 μM (2). Promising inhibition activity was shown by both the compounds against AChE and BChE in comparison with standard drugs available in the market such as allanzanthane and galanthamine. The inhibition efficiency of both the natural products was determined in a dose dependent manner.

  14. Amyotrophic lateral sclerosis affects cortical and subcortical activity underlying motor inhibition and action monitoring.

    PubMed

    Mohammadi, Bahram; Kollewe, Katja; Cole, David M; Fellbrich, Anja; Heldmann, Marcus; Samii, Amir; Dengler, Reinhard; Petri, Susanne; Münte, Thomas F; Krämer, Ulrike M

    2015-08-01

    Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder characterized by muscular atrophy, spasticity, and bulbar signs caused by loss of upper and lower motor neurons. Evidence suggests that ALS additionally affects other brain areas including premotor cortex and supplementary motor area. Here, we studied movement execution and inhibition in ALS patients using a stop-signal paradigm and functional magnetic resonance imaging. Seventeen ALS patients and 17 age-matched healthy controls performed a stop-signal task that required responding with a button press to a right- or left-pointing black arrow (go-stimuli). In stop-trials, a red arrow (stop-stimulus) was presented shortly after the black arrow indicating to withhold the prepared movement. Patients had by trend higher reaction times in go-trials but did not differ significantly in their inhibition performance. Patients showed stronger inhibition-related activity in inferior, superior, and middle frontal gyri as well as in putamen and pallidum. Error-related activity, conversely, was found to be stronger in healthy controls, particularly in the insula bilaterally. Patients also showed increased activity in the motor cortex during button presses. The results provide evidence for altered prefrontal and subcortical networks underlying motor execution, motor inhibition, and error monitoring in ALS. © 2015 Wiley Periodicals, Inc.

  15. GABA/sub B/ receptor activation inhibits Ca/sup 2 +/-activated potassium channels in synaptosomes: involvement of G-proteins

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Ticku, M.K.; Delgado, A.

    1989-01-01

    /sup 86/Rb-efflux assay from preloaded synaptosomes of rat cerebral cortex was developed to study the effect of GABA/sub B/ receptor agonist baclofen on Ca/sup 2 +/-activated K/sup +/-channels. Depolarization of /sup 86/Rb-loaded synaptosomes in physiological buffer increased Ca/sup 2 +/-activated /sup 86/Rb-efflux by 400%. The /sup 86/Rb-efflux was blocked by quinine sulfate, tetraethylammonium, and La/sup 3 +/ indicating the involvement of Ca/sup 2 +/-activated K/sup +/-channels. (-)Baclofen inhibited Ca/sup 2 +/-activated /sup 86/Rb-efflux in a stereospecific manner. The inhibitory effect of (-)baclofen was mediated by GABA/sub B/ receptor activation, since it was blocked by GABA/sub B/ antagonist phaclofen, but notmore » by bicuculline. Further, pertussis toxin also blocked the ability of baclofen or depolarizing action to affect Ca/sup 2 +/-activated K/sup +/-channels. These results suggest that baclofen inhibits Ca/sup 2 +/-activated K/sup +/-channels in synaptosomes and these channels are regulated by G-proteins. This assay may provide an ideal in vitro model to study GABA/sub B/ receptor pharmacology.« less

  16. Young Children with Autism Spectrum Disorder Do Not Preferentially Attend to Biological Motion

    ERIC Educational Resources Information Center

    Annaz, Dagmara; Campbell, Ruth; Coleman, Mike; Milne, Elizabeth; Swettenham, John

    2012-01-01

    Preferential attention to biological motion can be seen in typically developing infants in the first few days of life and is thought to be an important precursor in the development of social communication. We examined whether children with autism spectrum disorder (ASD) aged 3-7 years preferentially attend to point-light displays depicting…

  17. Transcranial magnetic and electrical stimulation compared: does TES activate intracortical neuronal circuits?

    PubMed

    Brocke, J; Irlbacher, K; Hauptmann, B; Voss, M; Brandt, S A

    2005-12-01

    To determine whether, and under which conditions, transcranial electrical stimulation (TES) and transcranial magnetic stimulation (TMS) can activate similar neuronal structures of the human motor cortex, as indicated by electromyographic recordings. Focal TMS was performed on three subjects inducing a postero-anterior directed current (p-a), TES with postero-anteriorly (p-a) and latero-medially (l-m) oriented electrodes. We analyzed the onset latencies and amplitudes (single-pulse) and intracortical inhibition and excitation (paired-pulse). TMS p-a and TES p-a produced muscle responses with the same onset latency, while TES l-m led to 1.4-1.9 ms shorter latencies. Paired-pulse TMS p-a and TES p-a induced inhibition at short inter-stimulus intervals (ISI) (maximum: 2-3 ms) and facilitation at longer ISIs (maximum: 10 ms). No inhibition but a strong facilitation was obtained from paired-pulse TES l-m (ISIs 1-5 ms). Our findings support the hypothesis, that current direction is the most relevant factor in determining the mode of activation for both TMS and TES: TMS p-a and TES p-a are likely to activate the corticospinal neurons indirectly. In contrast, TES l-m may preferentially activate the corticospinal fibres directly, distant of the neuronal body. TES is a suitable tool to induce intracortical inhibition and excitation.

  18. SN1 reactions in supercritical carbon dioxide in the presence of alcohols: the role of preferential solvation.

    PubMed

    Delgado-Abad, Thais; Martínez-Ferrer, Jaime; Acerete, Rafael; Asensio, Gregorio; Mello, Rossella; González-Núñez, María Elena

    2016-07-06

    Ethanol () inhibits SN1 reactions of alkyl halides in supercritical carbon dioxide (scCO2) and gives no ethers as products. The unexpected behaviour of alcohols in the reaction of alkyl halides with 1,3-dimethoxybenzene () in scCO2 under different conditions is rationalised in terms of Brønsted and Lewis acid-base equilibria of reagents, intermediates, additives and products in a singular solvent characterised by: (i) the strong quadrupole and Lewis acid character of carbon dioxide, which hinders SN2 paths by strongly solvating basic solutes; (ii) the weak Lewis base character of carbon dioxide, which prevents it from behaving as a proton sink; (iii) the compressible nature of scCO2, which enhances the impact of preferential solvation on carbon dioxide availability for the solvent-demanding rate determining step.

  19. Palmatine, a protoberberine alkaloid, inhibits both Ca2+- and cAMP-activated Cl− secretion in isolated rat distal colon

    PubMed Central

    Wu, D Z; Yuan, J Y; Shi, H L; Hu, Z B

    2008-01-01

    Background and purpose: The protoberberine alkaloid berberine has been reported to inhibit colonic Cl− secretion. However, it is not known if other protoberberine alkaloids share these effects. We have therefore selected another protoberberine alkaloid, palmatine, to assess its effects on active ion transport across rat colonic epithelium. Experimental approach: Rat colonic mucosa was mounted in Ussing chambers and short circuit current (I SC), apical Cl− current and basolateral K+ current were recorded. Intracellular cAMP content was determined by an enzyme immunoassay. Intracellular Ca2+ concentration was measured with Fura-2 AM. Key results: Palmatine inhibited carbachol-induced Ca2+-activated Cl− secretion and the carbachol-induced increase of intracellular Ca2+ concentration. Palmatine also inhibited cAMP-activated Cl− secretion induced by prostaglandin E2 (PGE2) or forskolin. Palmatine prevented the elevation of intracellular cAMP by forskolin. Determination of apical Cl− currents showed that palmatine suppressed the forskolin-stimulated, apical cAMP-activated Cl− current but not the carbachol-stimulated apical Ca2+-activated Cl− current. Following permeabilization of apical membranes with nystatin, we found that palmatine inhibited a carbachol-stimulated basolateral K+ current that was sensitive to charybdotoxin and resistant to chromanol 293B. However, the forskolin-stimulated basolateral K+ current inhibited by palmatine was specifically blocked by chromanol 293B and not by charybdotoxin. Conclusions and implications: Palmatine attenuated Ca2+-activated Cl− secretion through inhibiting basolateral charybdotoxin-sensitive, SK4 K+ channels, whereas it inhibited cAMP-activated Cl− secretion by inhibiting apical CFTR Cl− channels and basolateral chromanol 293B-sensitive, KvLQT1 K+ channels. PMID:18204477

  20. TSG-6 Regulates Bone Remodeling through Inhibition of Osteoblastogenesis and Osteoclast Activation*S⃞

    PubMed Central

    Mahoney, David J.; Mikecz, Katalin; Ali, Tariq; Mabilleau, Guillaume; Benayahu, Dafna; Plaas, Anna; Milner, Caroline M.; Day, Anthony J.; Sabokbar, Afsaneh

    2008-01-01

    TSG-6 is an inflammation-induced protein that is produced at pathological sites, including arthritic joints. In animal models of arthritis, TSG-6 protects against joint damage; this has been attributed to its inhibitory effects on neutrophil migration and plasmin activity. Here we investigated whether TSG-6 can directly influence bone erosion. Our data reveal that TSG-6 inhibits RANKL-induced osteoclast differentiation/activation from human and murine precursor cells, where elevated dentine erosion by osteoclasts derived from TSG-6-/- mice is consistent with the very severe arthritis seen in these animals. However, the long bones from unchallenged TSG-6-/- mice were found to have higher trabecular mass than controls, suggesting that in the absence of inflammation TSG-6 has a role in bone homeostasis; we have detected expression of the TSG-6 protein in the bone marrow of unchallenged wild type mice. Furthermore, we have observed that TSG-6 can inhibit bone morphogenetic protein-2 (BMP-2)-mediated osteoblast differentiation. Interaction analysis revealed that TSG-6 binds directly to RANKL and to BMP-2 (as well as other osteogenic BMPs but not BMP-3) via composite surfaces involving its Link and CUB modules. Consistent with this, the full-length protein is required for maximal inhibition of osteoblast differentiation and osteoclast activation, although the isolated Link module retains significant activity in the latter case. We hypothesize that TSG-6 has dual roles in bone remodeling; one protective, where it inhibits RANKL-induced bone erosion in inflammatory diseases such as arthritis, and the other homeostatic, where its interactions with BMP-2 and RANKL help to balance mineralization by osteoblasts and bone resorption by osteoclasts. PMID:18586671

  1. Inhibition of thyroid hormone sulfotransferase activity by brominated flame retardants and halogenated phenolics

    PubMed Central

    Butt, Craig M.; Stapleton, Heather M.

    2013-01-01

    Many halogenated organic contaminants (HOCs) are considered endocrine disruptors and affect the hypothalamic-pituitary-thyroid axis, often by interfering with circulating levels of thyroid hormones (THs). This study investigated one potential mechanism for TH disruption, inhibition of sulfotransferase activity. One of the primary roles of TH sulfation is to support the regulation of biologically active T3 through the formation of inactive THs. This study investigated TH sulfotransferase inhibition by 14 hydroxylated polybrominated diphenyl ethers (OH-BDEs), BDE 47, triclosan, and fluorinated, chlorinated, brominated and iodinated analogues of 2,4,6-trihalogenated phenol and BPA. A new mass spectrometry-based method was also developed to measure the formation rates of 3,3′-T2 sulfate (3,3′-T2S). Using pooled human liver cytosol we investigated the influence of these HOCs on the sulfation of 3,3′-T2, a major substrate for TH sulfation. For the formation of 3,3′-T2 sulfate, the Michaelis constant (Km) was 1070 ± 120 nM and the Vmax was 153 ± 6.6 pmol/min.mg protein. All chemicals investigated inhibited sulfotransferase activity with the exception of BDE 47. The 2,4,6-trihalogenated phenols were the most potent inhibitors followed by the OH-BDEs and then halogenated BPAs. The IC50 concentrations for the OH-BDEs were primarily in the low nM range, which may be environmentally relevant. In silico molecular modeling techniques were also used to simulate OH-BDE binding with SULT1A1. This study suggests that some HOCs, including anti-microbial chemicals and metabolites of flame retardants, may interfere with TH regulation through inhibition of sulfotransferase activity. PMID:24089703

  2. Physalin B inhibits Rhodnius prolixus hemocyte phagocytosis and microaggregation by the activation of endogenous PAF-acetyl hydrolase activities.

    PubMed

    Castro, D P; Figueiredo, M B; Genta, F A; Ribeiro, I M; Tomassini, T C B; Azambuja, P; Garcia, E S

    2009-06-01

    The effects of physalin B (a natural secosteroidal chemical from Physalis angulata, Solanaceae) on phagocytosis and microaggregation by hemocytes of 5th-instar larvae of Rhodnius prolixus were investigated. In this insect, hemocyte phagocytosis and microaggregation are known to be induced by the platelet-activating factor (PAF) or arachidonic acid (AA) and regulated by phospholipase A(2) (PLA(2)) and PAF-acetyl hydrolase (PAF-AH) activities. Phagocytic activity and formation of hemocyte microaggregates by Rhodnius hemocytes were strongly blocked by oral treatment of this insect with physalin B (1mug/mL of blood meal). The inhibition induced by physalin B was reversed for both phagocytosis and microaggregation by exogenous arachidonic acid (10microg/insect) or PAF (1microg/insect) applied by hemocelic injection. Following treatment with physalin B there were no significant alterations in PLA(2) activities, but a significant enhancement of PAF-AH was observed. These results show that physalin B inhibits hemocytic activity by depressing insect PAF analogous (iPAF) levels in hemolymph and confirm the role of PAF-AH in the cellular immune reactions in R. prolixus.

  3. Antiproliferative activity of flavonoids: influence of the sequential methoxylation state of the flavonoid structure.

    PubMed

    Moghaddam, Ghazaal; Ebrahimi, Soltan Ahmad; Rahbar-Roshandel, Nahid; Foroumadi, Alireza

    2012-07-01

    Dracocephalum kotschyi Boiss. has been used as part of an ethnobotanical remedy against many forms of human cancer in Iran. It has been demonstrated that a flavonoid named xanthomicrol from D. kotschyi contributes to its preferential antiproliferative activity against malignant cells. In the present study, the antiproliferative activity of its flavonoid fraction was further characterized. Using liquid-liquid extraction and a semi-preparative reversed-phase HPLC method, eight flavonoid aglycones were isolated from the aerial parts of the plant and their identities were confirmed through MS and NMR analyses as luteolin, naringenin, apigenin, isokaempferide, cirsimaritin, penduletin, xanthomicrol and calycopterin. The in vitro antiproliferative activity of each compound was evaluated against a panel of established normal and malignant cell lines using the MTT assay and some structure-activity relationships were observed. The hydroxyflavones (luteolin, apigenin and isokaempferide) exerted comparable antiproliferative activities against malignant and normal cells, while the methoxylated hydroxyflavones (cirsimaritin, penduletin, xanthomicrol and calycopterin) showed preferential activities against tumor cells. This activity may be of value in treating tumors as it would exert few side effects in normal tissues. Xanthomicrol selectively inhibited the growth of human gastric adenocarcinoma, while calycopterin selectively prevented human acute promyelocytic leukemia and human colon carcinoma cells proliferation. Copyright © 2011 John Wiley & Sons, Ltd.

  4. Preferential Solvation of Silver (I) Bromate in Methanol-Dimethylsulfoxide Mixtures

    NASA Astrophysics Data System (ADS)

    Janardhanan, S.; Kalidas, C.

    1984-06-01

    The solubiltiy of silver bromate, the Gibbs transfer energy of Ag+ and BrO3- and the solvent transport number in methanol-dimethyl sulfoxide mixtures are reported. The solubility of silver bromate increases with addition of DMSO. The Gibbs energy of transfer of the silver ion (based on the ferrocene reference method) decreases, while that of the bromate ion becomes slightly negative with the addition of DMSO. The solvent transport number A passes through a maximum (⊿ = 1.0 at XDMSO = 0.65. From these results, it is concluded that the silver ion is preferentially solvated by DMSO whereas the bromate ion shows no preferential solvation.

  5. Inhibition of host extracellular signal-regulated kinase (ERK) activation decreases new world alphavirus multiplication in infected cells

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Voss, Kelsey; Amaya, Moushimi; Mueller, Claudius

    New World alphaviruses belonging to the family Togaviridae are classified as emerging infectious agents and Category B select agents. Our study is focused on the role of the host extracellular signal-regulated kinase (ERK) in the infectious process of New World alphaviruses. Infection of human cells by Venezuelan equine encephalitis virus (VEEV) results in the activation of the ERK-signaling cascade. Inhibition of ERK1/2 by the small molecule inhibitor Ag-126 results in inhibition of viral multiplication. Ag-126-mediated inhibition of VEEV was due to potential effects on early and late stages of the infectious process. While expression of viral proteins was down-regulated inmore » Ag-126 treated cells, we did not observe any influence of Ag-126 on the nuclear distribution of capsid. Finally, Ag-126 exerted a broad-spectrum inhibitory effect on New World alphavirus multiplication, thus indicating that the host kinase, ERK, is a broad-spectrum candidate for development of novel therapeutics against New World alphaviruses. - Highlights: • VEEV infection activated multiple components of the ERK signaling cascade. • Inhibition of ERK activation using Ag-126 inhibited VEEV multiplication. • Activation of ERK by Ceramide C6 increased infectious titers of TC-83. • Ag-126 inhibited virulent strains of all New World alphaviruses. • Ag-126 treatment increased percent survival of infected cells.« less

  6. Preferential flow across scales: how important are plot scale processes for a catchment scale model?

    NASA Astrophysics Data System (ADS)

    Glaser, Barbara; Jackisch, Conrad; Hopp, Luisa; Klaus, Julian

    2017-04-01

    Numerous experimental studies showed the importance of preferential flow for solute transport and runoff generation. As a consequence, various approaches exist to incorporate preferential flow in hydrological models. However, few studies have applied models that incorporate preferential flow at hillslope scale and even fewer at catchment scale. Certainly, one main difficulty for progress is the determination of an adequate parameterization for preferential flow at these spatial scales. This study applies a 3D physically based model (HydroGeoSphere) of a headwater region (6 ha) of the Weierbach catchment (Luxembourg). The base model was implemented without preferential flow and was limited in simulating fast catchment responses. Thus we hypothesized that the discharge performance can be improved by utilizing a dual permeability approach for a representation of preferential flow. We used the information of bromide irrigation experiments performed on three 1m2 plots to parameterize preferential flow. In a first step we ran 20.000 Monte Carlo simulations of these irrigation experiments in a 1m2 column of the headwater catchment model, varying the dual permeability parameters (15 variable parameters). These simulations identified many equifinal, yet very different parameter sets that reproduced the bromide depth profiles well. Therefore, in the next step we chose 52 parameter sets (the 40 best and 12 low performing sets) for testing the effect of incorporating preferential flow in the headwater catchment scale model. The variability of the flow pattern responses at the headwater catchment scale was small between the different parameterizations and did not coincide with the variability at plot scale. The simulated discharge time series of the different parameterizations clustered in six groups of similar response, ranging from nearly unaffected to completely changed responses compared to the base case model without dual permeability. Yet, in none of the groups the

  7. Differential Effects of Tautomycetin and Its Derivatives on Protein Phosphatase Inhibition, Immunosuppressive Function and Antitumor Activity

    PubMed Central

    Niu, Mingshan; Sun, Yan; Liu, Bo

    2012-01-01

    In the present work, we studied the structure-activity relationship (SAR) of tautomycetin (TMC) and its derivatives. Further, we demonstrated the correlation between the immunosuppressive fuction, anticancer activity and protein phosphatase type 1 (PP1) inhibition of TMC and its derivatives. We have prepared some TMC derivatives via combinatorial biosynthesis, isolation from fermentation broth or chemical degradation of TMC. We found that the immunosuppressive activity was correlated with anticancer activity for TMC and its analog compounds, indicating that TMC may home at the same targets for its immunosuppressive and anticancer activities. Interestingly, TMC-F1, TMC-D1 and TMC-D2 all retained significant, albeit reduced PP1 inhibitory activity compared to TMC. However, only TMC-D2 showed immunosuppressive and anticancer activities in studies carried out in cell lines. Moreover, TMC-Chain did not show any significant inhibitory activity towards PP1 but showed strong growth inhibitory effect. This observation implicates that the maleic anhydride moiety of TMC is critical for its phosphatase inhibitory activity whereas the C1-C18 moiety of TMC is essential for the inhibition of tumor cell proliferation. Furthermore, we measured in vivo phosphatase activities of PP1 in MCF-7 cell extracts treated with TMC and its related compounds, and the results indicate that the cytotoxicity of TMC doesn't correlate with its in vivo PP1 inhibition activity. Taken together, our study suggests that the immunosuppressive and anticancer activities of TMC are not due to the inhibition of PP1. Our results provide a novel insight for the elucidation of the underlying molecular mechanisms of TMC's important biological functions. PMID:22563261

  8. Antioxidant activity and peroxidase inhibition of Amazonian plants extracts traditionally used as anti-inflammatory.

    PubMed

    de Vargas, Fabiano S; Almeida, Patricia D O; de Boleti, Ana Paula A; Pereira, Maria M; de Souza, Tatiane P; de Vasconcellos, Marne C; Nunez, Cecilia Veronica; Pohlit, Adrian M; Lima, Emerson S

    2016-02-27

    The Amazon is the largest rainforest in the world and is home to a rich biodiversity of medicinal plants. Several of these plants are used by the local population for the treatment of diseases, many of those with probable anti-inflammatory effect. The aim of the present investigation was to evaluate the in vitro antioxidant and anti-peroxidases potential of the ethanol extracts of five plants from the Brazilian Amazon (Byrsonima japurensis, Calycophyllum spruceanum, Maytenus guyanensis, Passiflora nitida and Ptychopetalum olacoides). DPPH, ABTS, superoxide anion radical, singlet oxygen and the β-carotene bleaching methods were employed for characterization of free radical scavenging activity. Also, total polyphenols were determined. Antioxidant activities were evaluated using murine fibroblast NIH3T3 cell. Inhibition of HRP and MPO were evaluated using amplex red® as susbtract. The stem bark extracts of C. spruceanum and M. guyanensis provided the highest free radical scavenging activities. C. spruceanum exhibited IC50 = 7.5 ± 0.9, 5.0 ± 0.1, 18.2 ± 3.0 and 92.4 ± 24.8 μg/mL for DPPH(•), ABTS(+•), O2 (-•) and (1)O2 assays, respectively. P. olacoides and C. spruceanum extracts also inhibited free radicals formation in the cell-based assay. At a concentration of 100 μg/mL, the extracts of C. spruceanum, B. japurensis inhibited horseradish peroxidase by 62 and 50 %, respectively. C. spruceanum, M. guyanensis, B. japurensis also inhibited myeloperoxidase in 72, 67 and 56 %, respectively. This work supports the folk use these species that inhibited peroxidases and exhibited significant free radical scavenging and antioxidant activities what can be related to treatment of inflammation.

  9. Cigarette smoke exposure inhibits contact hypersensitivity via the generation of platelet activating factor agonists

    PubMed Central

    Sahu, Ravi P.; Petrache, Irina; Van Demark, Mary J; Rashid, Badri M.; Ocana, Jesus A.; Tang, Yuxuan; Yi, Qiaofang; Turner, Matthew J.; Konger, Raymond L.; Travers, Jeffrey B.

    2013-01-01

    Previous studies have established that pro-oxidative stressors suppress host immunity due to their ability to generate oxidized lipids with PAF-receptor (PAF-R) agonist activity. Although exposure to the pro-oxidative stressor cigarette smoke (CS) is known to exert immunomodulatory effects, little is known regarding the role of platelet-activating factor (PAF) in these events. The current studies sought to determine the role of PAF-R signaling in CS-mediated immunomodulatory effects. We demonstrate that CS exposure induces the generation of a transient PAF-R agonistic activity in the blood of mice. CS exposure inhibits contact hypersensitivity in a PAF-R-dependent manner as PAF-R-deficient mice were resistant to these effects. Blocking PAF-R agonist production either by systemic antioxidants or treatment with serum PAF-acetyl hydrolase enzyme blocked both the CS-mediated generation of PAF-R-agonists and PAF-R dependent inhibition of CHS reactions, indicating a role for oxidized glycerophosphocholines with PAF-R agonistic activity in this process. In addition, cyclooxygenase-2 (COX-2) inhibition did not block PAF-R agonist production but prevented CS-induced inhibition of CHS. This suggests that COX-2 acts downstream of the PAF-R in mediating CS-induced systemic immunosuppression. Moreover, CS-exposure induced a significant increase in the expression of the regulatory T cell reporter gene in FoxP3EGFP mice but not in FoxP3EGFP mice on a PAF-R-deficient background. Finally, Treg depletion via anti-CD25 antibodies blocked CS-mediated inhibition of CHS, indicating the potential involvement of Tregs in CS-mediated systemic immunosuppression. These studies provide the first evidence that the pro-oxidative stressor CS can modulate cutaneous immunity via the generation of PAF-R agonists produced through lipid oxidation. PMID:23355733

  10. Network Evolution by Relevance and Importance Preferential Attachment

    DTIC Science & Technology

    2014-08-06

    Polytechnic Institute 110 8th Street Troy , NY 12180 -3522 ABSTRACT Network Evolution by Relevance and Importance Preferential Attachment Report Title...Science 286 (5439): 509-512. [3] Watts , Duncan J.; Strogatz, Steven H. (1998). ”Collective dynamics of ’small-world’ networks”. Nature 393 (6684): 440

  11. Inhibiting fungal multidrug resistance by disrupting an activator-Mediator interaction.

    PubMed

    Nishikawa, Joy L; Boeszoermenyi, Andras; Vale-Silva, Luis A; Torelli, Riccardo; Posteraro, Brunella; Sohn, Yoo-Jin; Ji, Fei; Gelev, Vladimir; Sanglard, Dominique; Sanguinetti, Maurizio; Sadreyev, Ruslan I; Mukherjee, Goutam; Bhyravabhotla, Jayaram; Buhrlage, Sara J; Gray, Nathanael S; Wagner, Gerhard; Näär, Anders M; Arthanari, Haribabu

    2016-02-25

    Eukaryotic transcription activators stimulate the expression of specific sets of target genes through recruitment of co-activators such as the RNA polymerase II-interacting Mediator complex. Aberrant function of transcription activators has been implicated in several diseases. However, therapeutic targeting efforts have been hampered by a lack of detailed molecular knowledge of the mechanisms of gene activation by disease-associated transcription activators. We previously identified an activator-targeted three-helix bundle KIX domain in the human MED15 Mediator subunit that is structurally conserved in Gal11/Med15 Mediator subunits in fungi. The Gal11/Med15 KIX domain engages pleiotropic drug resistance transcription factor (Pdr1) orthologues, which are key regulators of the multidrug resistance pathway in Saccharomyces cerevisiae and in the clinically important human pathogen Candida glabrata. The prevalence of C. glabrata is rising, partly owing to its low intrinsic susceptibility to azoles, the most widely used antifungal agent. Drug-resistant clinical isolates of C. glabrata most commonly contain point mutations in Pdr1 that render it constitutively active, suggesting that this transcriptional activation pathway represents a linchpin in C. glabrata multidrug resistance. Here we perform sequential biochemical and in vivo high-throughput screens to identify small-molecule inhibitors of the interaction of the C. glabrata Pdr1 activation domain with the C. glabrata Gal11A KIX domain. The lead compound (iKIX1) inhibits Pdr1-dependent gene activation and re-sensitizes drug-resistant C. glabrata to azole antifungals in vitro and in animal models for disseminated and urinary tract C. glabrata infection. Determining the NMR structure of the C. glabrata Gal11A KIX domain provides a detailed understanding of the molecular mechanism of Pdr1 gene activation and multidrug resistance inhibition by iKIX1. We have demonstrated the feasibility of small-molecule targeting of a

  12. Preferential attachment and growth dynamics in complex systems

    NASA Astrophysics Data System (ADS)

    Yamasaki, Kazuko; Matia, Kaushik; Buldyrev, Sergey V.; Fu, Dongfeng; Pammolli, Fabio; Riccaboni, Massimo; Stanley, H. Eugene

    2006-09-01

    Complex systems can be characterized by classes of equivalency of their elements defined according to system specific rules. We propose a generalized preferential attachment model to describe the class size distribution. The model postulates preferential growth of the existing classes and the steady influx of new classes. According to the model, the distribution changes from a pure exponential form for zero influx of new classes to a power law with an exponential cut-off form when the influx of new classes is substantial. Predictions of the model are tested through the analysis of a unique industrial database, which covers both elementary units (products) and classes (markets, firms) in a given industry (pharmaceuticals), covering the entire size distribution. The model’s predictions are in good agreement with the data. The paper sheds light on the emergence of the exponent τ≈2 observed as a universal feature of many biological, social and economic problems.

  13. Conformationally constrained peptides target the allosteric kinase dimer interface and inhibit EGFR activation.

    PubMed

    Fulton, Melody D; Hanold, Laura E; Ruan, Zheng; Patel, Sneha; Beedle, Aaron M; Kannan, Natarajan; Kennedy, Eileen J

    2018-03-15

    Although EGFR is a highly sought-after drug target, inhibitor resistance remains a challenge. As an alternative strategy for kinase inhibition, we sought to explore whether allosteric activation mechanisms could effectively be disrupted. The kinase domain of EGFR forms an atypical asymmetric dimer via head-to-tail interactions and serves as a requisite for kinase activation. The kinase dimer interface is primarily formed by the H-helix derived from one kinase monomer and the small lobe of the second monomer. We hypothesized that a peptide designed to resemble the binding surface of the H-helix may serve as an effective disruptor of EGFR dimerization and activation. A library of constrained peptides was designed to mimic the H-helix of the kinase domain and interface side chains were optimized using molecular modeling. Peptides were constrained using peptide "stapling" to structurally reinforce an alpha-helical conformation. Peptide stapling was demonstrated to notably enhance cell permeation of an H-helix derived peptide termed EHBI2. Using cell-based assays, EHBI2 was further shown to significantly reduce EGFR activity as measured by EGFR phosphorylation and phosphorylation of the downstream signaling substrate Akt. To our knowledge, this is the first H-helix-based compound targeting the asymmetric interface of the kinase domain that can successfully inhibit EGFR activation and signaling. This study presents a novel, alternative targeting site for allosteric inhibition of EGFR. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Interleukin-35 Inhibits Endothelial Cell Activation by Suppressing MAPK-AP-1 Pathway.

    PubMed

    Sha, Xiaojin; Meng, Shu; Li, Xinyuan; Xi, Hang; Maddaloni, Massimo; Pascual, David W; Shan, Huimin; Jiang, Xiaohua; Wang, Hong; Yang, Xiao-feng

    2015-07-31

    Vascular response is an essential pathological mechanism underlying various inflammatory diseases. This study determines whether IL-35, a novel responsive anti-inflammatory cytokine, inhibits vascular response in acute inflammation. Using a mouse model of LPS-induced acute inflammation and plasma samples from sepsis patients, we found that IL-35 was induced in the plasma of mice after LPS injection as well as in the plasma of sepsis patients. In addition, IL-35 decreased LPS-induced proinflammatory cytokines and chemokines in the plasma of mice. Furthermore, IL-35 inhibited leukocyte adhesion to the endothelium in the vessels of lung and cremaster muscle and decreased the numbers of inflammatory cells in bronchoalveolar lavage fluid. Mechanistically, IL-35 inhibited the LPS-induced up-regulation of endothelial cell (EC) adhesion molecule VCAM-1 through IL-35 receptors gp130 and IL-12Rβ2 via inhibition of the MAPK-activator protein-1 (AP-1) signaling pathway. We also found that IL-27, which shares the EBI3 subunit with IL-35, promoted LPS-induced VCAM-1 in human aortic ECs and that EBI3-deficient mice had similar vascular response to LPS when compared with that of WT mice. These results demonstrated for the first time that inflammation-induced IL-35 inhibits LPS-induced EC activation by suppressing MAPK-AP1-mediated VCAM-1 expression and attenuates LPS-induced secretion of proinflammatory cytokines/chemokines. Our results provide insight into the control of vascular inflammation by IL-35 and suggest that IL-35 is an attractive novel therapeutic reagent for sepsis and cardiovascular diseases. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. Rosmarinic acid counteracts activation of hepatic stellate cells via inhibiting the ROS-dependent MMP-2 activity: Involvement of Nrf2 antioxidant system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lu, Changfang; Zou, Yu; Liu, Yuzhang

    Recently, oxidative stress is involved in hepatofibrogenesis. Matrix metalloproteinase-2 (MMP-2) is required for activation of hepatic stellate cells (HSCs) in response to reactive oxygen species (ROS). This study was designed to explore the hypothesis that the inhibitory effect of rosmarinic acid (RA) on HSCs activation might mainly result from its antioxidant capability by increasing the synthesis of glutathione (GSH) involved in nuclear factor kappa B (NF-κB)-dependent inhibition of MMP-2 activity. Here, we demonstrate that RA reverses activated HSCs to quiescent cells. Concomitantly, RA inhibits MMP-2 activity. RNA interference-imposed knockdown of NF-κB abolished down-regulation of MMP-2 by RA. RA-mediated inactivation ofmore » NF-κB could be blocked by the diphenyleneiodonium chloride (DPI; a ROS inhibitor). Conversely, transfection of dominant-negative (DN) mutant of extracellular signal-regulated kinases 2 (ERK2), c-Jun N-terminal kinase 1 (JNK1), or p38α kinase had no such effect. Simultaneously, RA suppresses ROS generation and lipid peroxidation (LPO) whereas increases cellular GSH in HSC-T6 cells. Furthermore, RA significantly increased antioxidant response element (ARE)-mediated luciferase activity, nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and catalytic subunits from glutamate cysteine ligase (GCLc) expression, but not modulatory subunits from GCL (GCLm). RA-mediated up-regulation of GClc is inhibited by the shRNA-induced Nrf2 knockdown. The knocking down of Nrf2 or buthionine sulfoximine (a GCL inhibitor) abolished RA-mediated inhibition of ROS. Collectively, these results provide novel insights into the mechanisms of RA as an antifibrogenic candidate in the prevention and treatment of liver fibrosis. - Highlights: • RA reverses activated HSCs to quiescent cells. • RA suppresses MMP-2 activity through a NF-κB-dependent pathway. • Inhibition of oxidative stress by RA is dependent on nuclear translocation

  16. Dunye Guanxinning Improves Acute Myocardial Ischemia-Reperfusion Injury by Inhibiting Neutrophil Infiltration and Caspase-1 Activity

    PubMed Central

    Zhang, Q. G.; Wang, S. R.; Chen, X. M.; Guo, H. N.

    2018-01-01

    Acute myocardial infarction is the most serious manifestation of cardiovascular disease, and it is a life-threatening condition. Dunye Guanxinning (DG) is a protective traditional Chinese patent herbal medicine with high clinical efficacy and suitable for the treatment of myocardial infarction. However, the mechanism through which it is beneficial is unclear. In this study, we hypothesized that DG improves acute myocardial ischemia-reperfusion injury by inhibiting neutrophil infiltration and caspase-1 activity. We found that DG administration decreased infarct size and cardiomyocyte apoptosis and improved left ventricular ejection fraction, fractional shortening, end-systolic volume index, end-systolic diameter, and carotid arterial blood flow output in rats. DG administration also improved hemorheological parameters, myocardial damage biomarkers, and oxidative stress indexes. The findings showed that DG administration inhibited neutrophil infiltration and reduced the serum interleukin-1 beta (IL-1β) level and myocardial IL-1β maturation. Moreover, DG administration inhibited caspase-1 activity and activated adenosine monophosphate-activated protein kinase (AMPK) phosphorylation in rat hearts. These results suggested that DG administration inhibits inflammasome activity and IL-1β release through the AMPK pathway. Our findings support the clinical efficacy of DG and partially reveal its mechanism, which is beneficial for understanding the therapeutic effects of this protective traditional Chinese patent drug. PMID:29674944

  17. Platycodin D inhibits tumor growth by antiangiogenic activity via blocking VEGFR2-mediated signaling pathway

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Luan, Xin; Gao, Yun-Ge; Guan, Ying-Yun

    2014-11-15

    Platycodin D (PD) is an active component mainly isolated from the root of Platycodon grandiflorum. Recent studies proved that PD exhibited inhibitory effect on proliferation, migration, invasion and xenograft growth of diverse cancer cell lines. However, whether PD is suppressive for angiogenesis, an important hallmark in cancer development, remains unknown. Here, we found that PD could dose-dependently inhibit human umbilical vein endothelial cell (HUVEC) proliferation, motility, migration and tube formation. PD also significantly inhibited angiogenesis in the chick embryo chorioallantoic membrane (CAM). Moreover, the antiangiogenic activity of PD contributed to its in vivo anticancer potency shown in the decreased microvesselmore » density and delayed growth of HCT-15 xenograft in mice with no overt toxicity. Western blot analysis indicated that PD inhibited the phosphorylation of VEGFR2 and its downstream protein kinase including PLCγ1, JAK2, FAK, Src, and Akt in endothelial cells. Molecular docking simulation showed that PD formed hydrogen bonds and hydrophobic interactions within the ATP binding pocket of VEGFR2 kinase domain. The present study firstly revealed the high antiangiogenic activity and the underlying molecular basis of PD, suggesting that PD may be a potential antiangiogenic agent for angiogenesis-related diseases. - Highlights: • Platycodin D inhibits HUVEC proliferation, motility, migration and tube formation. • Platycodin D inhibits the angiogenesis in chick embryo chorioallantoic membrane. • Platycodin D suppresses the angiogenesis and growth of HCT-15 xenograft in mice. • Platycodin D inhibits the phosphorylation of VEGFR2 and downstream kinases in HUVEC.« less

  18. Effects of surfactants on lipase structure, activity, and inhibition.

    PubMed

    Delorme, Vincent; Dhouib, Rabeb; Canaan, Stéphane; Fotiadu, Frédéric; Carrière, Frédéric; Cavalier, Jean-François

    2011-08-01

    Lipase inhibitors are the main anti-obesity drugs prescribed these days, but the complexity of their mechanism of action is making it difficult to develop new molecules for this purpose. The efficacy of these drugs is known to depend closely on the physico-chemistry of the lipid-water interfaces involved and on the unconventional behavior of the lipases which are their target enzymes. The lipolysis reaction which occurs at an oil-water interface involves complex equilibria between adsorption-desorption processes, conformational changes and catalytic mechanisms. In this context, surfactants can induce significant changes in the partitioning of the enzyme and the inhibitor between the water phase and lipid-water interfaces. Surfactants can be found at the oil-water interface where they compete with lipases for adsorption, but also in solution in the form of micellar aggregates and monomers that may interact with hydrophobic parts of lipases in solution. These various interactions, combined with the emulsification and dispersion of insoluble substrates and inhibitors, can either promote or decrease the activity and the inhibition of lipases. Here, we review some examples of the various effects of surfactants on lipase structure, activity and inhibition, which show how complex the various equilibria involved in the lipolysis reaction tend to be.

  19. Selective inhibition of influenza virus protein synthesis by inhibitors of DNA function. [UV radiation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Minor, P.D.; Dimmock, N.J.

    1977-05-15

    Various known inhibitors of cellular DNA function were shown to inhibit cellular RNA synthesis and influenza (fowl plague) virus multiplication. The drugs were investigated for their effect upon the synthesis of influenza virus proteins. According to this effect they could be classified with previously studied compounds as follows: Group I (ethidium bromide, proflavine, and N-nitroquinoline-N-oxide) inhibited both viral and cellular protein synthesis; Group II (nogalomycin, daunomycin and ..cap alpha..-amanitin) inhibited viral but not cellular protein synthesis, and all viral proteins were inhibited coordinately; Group III (mithramycin, echinomycin, and actinomycin D) inhibited all viral but not cellular protein synthesis at highmore » concentrations, but at a lower critical concentration inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein preferentially; Group IV(uv irradiation and camptothecin) inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein, but not other viral proteins, even at high doses. The mode of action of these inhibitors is discussed in relation to the mechanism of the nuclear events upon which influenza virus multiplication is dependent.« less

  20. Inhibition of Nuclear Transcription Factor-κB and Activation of Peroxisome Proliferator-Activated Receptors in HepG2 Cells by Cucurbitane-Type Triterpene Glycosides from Momordica charantia

    PubMed Central

    Nhiem, Nguyen Xuan; Yen, Pham Hai; Ngan, Nguyen Thi Thanh; Quang, Tran Hong; Kiem, Phan Van; Minh, Chau Van; Tai, Bui Huu; Cuong, Nguyen Xuan; Song, Seok Bean

    2012-01-01

    Abstract Momordica charantia: is used to treat various diseases, including inflammatory conditions. Previous reports indicated that the extract of this plant inhibits activation of nuclear transcription factor-κB (NF-κB) but activates peroxisome proliferator-activated receptor (PPAR). Additionally, cucurbitane-type triterpene glycosides are the main bioactive components of the fruit of M. charantia. Therefore, we investigated the anti-inflammatory activity of 17 cucurbitane-type triterpene glycosides (1–17) isolated from this plant. Their inhibition of NF-κB and activation of PPAR activities in HepG2 cells were measured using luciferase reporter and PPAR subtype transactivation assays. Compounds 6 and 8 were found to inhibit NF-κB activation stimulated by tumor necrosis factor-α (TNFα) in a dose-dependent manner. With 50% inhibition concentration (IC50) values of 0.4 μM, compounds 6 and 8 were more potent inhibitors than the positive control, sulfasalazine (IC50=0.9 μM). Compounds 4, 6, and 8 also inhibited TNFα-induced expressions of inducible nitric oxide synthase and cyclooxygenase-2 mRNA. However, only compound 13 significantly increased PPARγ transactivation. PMID:22248180

  1. Lipid peroxidation inhibition and antiradical activities of some leaf fractions of Mangifera indica.

    PubMed

    Badmus, Jelili A; Adedosu, Temitope O; Fatoki, John O; Adegbite, Victor A; Adaramoye, Oluwatosin A; Odunola, Oyeronke A

    2011-01-01

    This study was undertaken to assess in vitro lipid peroxidation inhibitions and anti-radical activities of methanolic, chloroform, ethyl acetate and water fractions of Mangifera indica leaf. Inhibition of Fe(2+)-induced lipid peroxidation (LPO) in egg, brain, and liver homogenates, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl (OH-) radical scavenging activities were evaluated. Total phenol was assessed in all fractions, and the reducing power of methanolic fraction was compared to gallic acid and ascorbic acid. The results showed that Fe2+ induced significant lipid peroxidation (LPO) in all the homogenates. Ethyl acetate fraction showed the highest percentage inhibition of LPO in both egg yolk (68.3%) and brain (66.3%), while the aqueous fraction exerted the highest inhibition in liver homogenate (89.1%) at a concentration of 10 microg/mL. These observed inhibitions of LPO by these fractions were higher than that of ascorbic acid used as a standard. The DPPH radical scavenging ability exhibited by ethyl acetate fraction was found to be the highest with IC50 value of 1.5 microg/mL. The ethyl acetate and methanolic fractions had the highest OH- radical scavenging ability with the same IC50 value of 5 microg/mL. The total phenol content of ethyl acetate fraction was the highest with 0.127 microg/mg gallic acid equivalent (GAE). The reductive potential of methanolic fraction showed a concentration-dependent increase. This study showed that inhibition of LPO and the DPPH and OH- radicals scavenging abilities of Mangifera indica leaf could be related to the presence of phenolic compounds. Therefore, the ethyl acetate fraction of the leaf may be a good source of natural antioxidative agent.

  2. Searching for differences in race: is there evidence for preferential detection of other-race faces?

    PubMed

    Lipp, Ottmar V; Terry, Deborah J; Smith, Joanne R; Tellegen, Cassandra L; Kuebbeler, Jennifer; Newey, Mareka

    2009-06-01

    Previous research has suggested that like animal and social fear-relevant stimuli, other-race faces (African American) are detected preferentially in visual search. Three experiments using Chinese or Indonesian faces as other-race faces yielded the opposite pattern of results: faster detection of same-race faces among other-race faces. This apparently inconsistent pattern of results was resolved by showing that Asian and African American faces are detected preferentially in tasks that have small stimulus sets and employ fixed target searches. Asian and African American other-race faces are found slower among Caucasian face backgrounds if larger stimulus sets are used in tasks with a variable mapping of stimulus to background or target. Thus, preferential detection of other-race faces was not found under task conditions in which preferential detection of animal and social fear-relevant stimuli is evident. Although consistent with the view that same-race faces are processed in more detail than other-race faces, the current findings suggest that other-race faces do not draw attention preferentially.

  3. LINE-1 Retroelements Complexed and Inhibited by Activation Induced Cytidine Deaminase

    PubMed Central

    Metzner, Mirjam; Jäck, Hans-Martin; Wabl, Matthias

    2012-01-01

    LINE-1 (abbreviated L1) is a major class of retroelements in humans and mice. If unrestricted, retroelements accumulate in the cytoplasm and insert their DNA into the host genome, with the potential to cause autoimmune disease and cancer. Retroviruses and other retroelements are inhibited by proteins of the APOBEC family, of which activation-induced cytidine deaminase (AID) is a member. Although AID is mainly known for being a DNA mutator shaping the antibody repertoire in B lymphocytes, we found that AID also restricts de novo L1 integrations in B- and non-B-cell lines. It does so by decreasing the protein level of open reading frame 1 (ORF1) of both exogenous and endogenous L1. In activated B lymphocytes, AID deficiency increased L1 mRNA 1.6-fold and murine leukemia virus (MLV) mRNA 2.7-fold. In cell lines and activated B lymphocytes, AID forms cytoplasmic high-molecular-mass complexes with L1 mRNA, which may contribute to L1 restriction. Because AID-deficient activated B lymphocytes do not express ORF1 protein, we suggest that ORF1 protein expression is inhibited by additional restriction factors in these cells. The greater increase in MLV compared to L1 mRNA in AID-deficient activated B lymphocytes may indicate less strict surveillance of retrovirus. PMID:23133680

  4. Amino acid conjugated antimicrobial drugs: Synthesis, lipophilicity- activity relationship, antibacterial and urease inhibition activity.

    PubMed

    Ullah, Atta; Iftikhar, Fatima; Arfan, Muhammad; Batool Kazmi, Syeda Tayyaba; Anjum, Muhammad Naveed; Haq, Ihsan-Ul; Ayaz, Muhammad; Farooq, Sadia; Rashid, Umer

    2018-02-10

    Present work describes the in vitro antibacterial evaluation of some new amino acid conjugated antimicrobial drugs. Structural modification was attempted on the three existing antimicrobial pharmaceuticals namely trimethoprim, metronidazole, isoniazid. Twenty one compounds from seven series of conjugates of these drugs were synthesized by coupling with some selected Boc-protected amino acids. The effect of structural features and lipophilicity on the antibacterial activity was investigated. The synthesized compounds were evaluated against five standard American type culture collection (ATCC) i.e. Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi strains of bacteria. Our results identified a close relationship between the lipophilicity and the activity. Triazine skeleton proved beneficial for the increase in hydrophobicity and potency. Compounds with greater hydrophobicity have shown excellent activities against Gram-negative strains of bacteria than Gram-positive. 4-amino unsubstituted trimethoprim-triazine derivative 7b have shown superior activity with MIC = 3.4 μM (2 μg/mL) for S. aureus and 1.1 μM (0.66 μg/mL) for E. coli. The synthesized compounds were also evaluated for their urease inhibition study. Microbial urease from Bacillus pasteurii was chosen for this study. Triazine derivative 7a showed excellent inhibition with IC 50  = 6.23 ± 0.09 μM. Docking studies on the crystal structure of B. pasteurii urease (PDB ID 4UBP) were carried out. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  5. Fluid shear stress inhibits TNF-alpha-induced apoptosis in osteoblasts: a role for fluid shear stress-induced activation of PI3-kinase and inhibition of caspase-3

    NASA Technical Reports Server (NTRS)

    Pavalko, Fredrick M.; Gerard, Rita L.; Ponik, Suzanne M.; Gallagher, Patricia J.; Jin, Yijun; Norvell, Suzanne M.

    2003-01-01

    In bone, a large proportion of osteoblasts, the cells responsible for deposition of new bone, normally undergo programmed cell death (apoptosis). Because mechanical loading of bone increases the rate of new bone formation, we hypothesized that mechanical stimulation of osteoblasts might increase their survival. To test this hypothesis, we investigated the effects of fluid shear stress (FSS) on osteoblast apoptosis using three osteoblast cell types: primary rat calvarial osteoblasts (RCOB), MC3T3-E1 osteoblastic cells, and UMR106 osteosarcoma cells. Cells were treated with TNF-alpha in the presence of cyclohexamide (CHX) to rapidly induce apoptosis. Osteoblasts showed significant signs of apoptosis within 4-6 h of exposure to TNF-alpha and CHX, and application of FSS (12 dyne/cm(2)) significantly attenuated this TNF-alpha-induced apoptosis. FSS activated PI3-kinase signaling, induced phosphorylation of Akt, and inhibited TNF-alpha-induced activation of caspase-3. Inhibition of PI3-kinase, using LY294002, blocked the ability of FSS to rescue osteoblasts from TNF-alpha-induced apoptosis and blocked FSS-induced inhibition of caspase-3 activation in osteoblasts treated with TNF-alpha. LY294002 did not, however, prevent FSS-induced phosphorylation of Akt suggesting that activation of Akt alone is not sufficient to rescue cells from apoptosis. This result also suggests that FSS can activate Akt via a PI3-kinase-independent pathway. These studies demonstrate for the first time that application of FSS to osteoblasts in vitro results in inhibition of TNF-alpha-induced apoptosis through a mechanism involving activation of PI3-kinase signaling and inhibition of caspases. FSS-induced activation of PI3-kinase may promote cell survival through a mechanism that is distinct from the Akt-mediated survival pathway. Copyright 2002 Wiley-Liss, Inc.

  6. Activation of PPARδ attenuates neurotoxicity by inhibiting lipopolysaccharide-triggered glutamate release in BV-2 microglial cells.

    PubMed

    Lee, Won Jin; Ham, Sun Ah; Yoo, Hyunjin; Hwang, Jung Seok; Yoo, Taesik; Paek, Kyung Shin; Lim, Dae-Seog; Han, Sung Gu; Lee, Chi-Ho; Hong, Kwonho; Seo, Han Geuk

    2018-02-01

    Neuroinflammation-associated release of glutamate from activated microglia has been implicated in the progression of neurodegenerative diseases. However, the regulatory mechanisms underlying this glutamate release are poorly understood. Here, we show that peroxisome proliferator-activated receptor delta (PPARδ) modulates neurotoxicity by inhibiting glutamate release in lipopolysaccharide (LPS)-activated BV-2 microglial cells. Activation of PPARδ by GW501516, a specific PPARδ agonist, inhibited glutamate release in BV-2 cells. This effect of GW501516 was significantly blocked by shRNA-mediated knockdown of PPARδ and by treatment with GSK0660, a specific PPARδ antagonist, indicating that PPARδ is associated with blockade of glutamate release. Additionally, GW501516-activated PPARδ suppressed generation of reactive oxygen species and expression of gp91phox, a functional subunit of NADPH oxidase 2, in BV-2 cells stimulated with LPS. The inhibitory effect of GW501516 on gp91phox expression and glutamate release was further potentiated in the presence of AG490, a specific inhibitor of janus kinase 2 (JAK2), leading to the inhibition of signal transducer and activator of transcription 1 (STAT1). By contrast, GW501516 upregulated the expression of suppressor of cytokine signaling 1 (SOCS1), an endogenous inhibitor of JAK2. Furthermore, neurotoxicity induced by conditioned media from LPS-stimulated BV-2 cells was significantly reduced when conditioned media from BV-2 cells treated with both LPS and GW501516 were used. These results indicate that PPARδ attenuates LPS-triggered neuroinflammation by enhancing SOCS1-mediated inhibition of JAK2/STAT1 signaling, thereby inhibiting neurotoxicity associated with glutamate release. © 2018 Wiley Periodicals, Inc.

  7. Preferential Generation of 15-HETE-PE Induced by IL-13 Regulates Goblet Cell Differentiation in Human Airway Epithelial Cells.

    PubMed

    Zhao, Jinming; Minami, Yoshinori; Etling, Emily; Coleman, John M; Lauder, Sarah N; Tyrrell, Victoria; Aldrovandi, Maceler; O'Donnell, Valerie; Claesson, Hans-Erik; Kagan, Valerian; Wenzel, Sally

    2017-12-01

    Type 2-associated goblet cell hyperplasia and mucus hypersecretion are well known features of asthma. 15-Lipoxygenase-1 (15LO1) is induced by the type 2 cytokine IL-13 in human airway epithelial cells (HAECs) in vitro and is increased in fresh asthmatic HAECs ex vivo. 15LO1 generates a variety of products, including 15-hydroxyeicosatetraenoic acid (15-HETE), 15-HETE-phosphatidylethanolamine (15-HETE-PE), and 13-hydroxyoctadecadienoic acid (13-HODE). In this study, we investigated the 15LO1 metabolite profile at baseline and after IL-13 treatment, as well as its influence on goblet cell differentiation in HAECs. Primary HAECs obtained from bronchial brushings of asthmatic and healthy subjects were cultured under air-liquid interface culture supplemented with arachidonic acid and linoleic acid (10 μM each) and exposed to IL-13 for 7 days. Short interfering RNA transfection and 15LO1 inhibition were applied to suppress 15LO1 expression and activity. IL-13 stimulation induced expression of 15LO1 and preferentially generated 15-HETE-PE in vitro, both of which persisted after removal of IL-13. 15LO1 inhibition (by short interfering RNA and chemical inhibitor) decreased IL-13-induced forkhead box protein A3 (FOXA3) expression and enhanced FOXA2 expression. These changes were associated with reductions in both mucin 5AC and periostin. Exogenous 15-HETE-PE stimulation (alone) recapitulated IL-13-induced FOXA3, mucin 5AC, and periostin expression. The results of this study confirm the central importance of 15LO1 and its primary product, 15-HETE-PE, for epithelial cell remodeling in HAECs.

  8. Transcriptome-Wide Identification of Preferentially Expressed Genes in the Hypothalamus and Pituitary Gland

    PubMed Central

    St-Amand, Jonny; Yoshioka, Mayumi; Tanaka, Keitaro; Nishida, Yuichiro

    2012-01-01

    To identify preferentially expressed genes in the central endocrine organs of the hypothalamus and pituitary gland, we generated transcriptome-wide mRNA profiles of the hypothalamus, pituitary gland, and parietal cortex in male mice (12–15 weeks old) using serial analysis of gene expression (SAGE). Total counts of SAGE tags for the hypothalamus, pituitary gland, and parietal cortex were 165824, 126688, and 161045 tags, respectively. This represented 59244, 45151, and 55131 distinct tags, respectively. Comparison of these mRNA profiles revealed that 22 mRNA species, including three potential novel transcripts, were preferentially expressed in the hypothalamus. In addition to well-known hypothalamic transcripts, such as hypocretin, several genes involved in hormone function, intracellular transduction, metabolism, protein transport, steroidogenesis, extracellular matrix, and brain disease were identified as preferentially expressed hypothalamic transcripts. In the pituitary gland, 106 mRNA species, including 60 potential novel transcripts, were preferentially expressed. In addition to well-known pituitary genes, such as growth hormone and thyroid stimulating hormone beta, a number of genes classified to function in transport, amino acid metabolism, intracellular transduction, cell adhesion, disulfide bond formation, stress response, transcription, protein synthesis, and turnover, cell differentiation, the cell cycle, and in the cytoskeleton and extracellular matrix were also preferentially expressed. In conclusion, the current study identified not only well-known hypothalamic and pituitary transcripts but also a number of new candidates likely to be involved in endocrine homeostatic systems regulated by the hypothalamus and pituitary gland. PMID:22649398

  9. Transcriptome-wide identification of preferentially expressed genes in the hypothalamus and pituitary gland.

    PubMed

    St-Amand, Jonny; Yoshioka, Mayumi; Tanaka, Keitaro; Nishida, Yuichiro

    2011-01-01

    To identify preferentially expressed genes in the central endocrine organs of the hypothalamus and pituitary gland, we generated transcriptome-wide mRNA profiles of the hypothalamus, pituitary gland, and parietal cortex in male mice (12-15 weeks old) using serial analysis of gene expression (SAGE). Total counts of SAGE tags for the hypothalamus, pituitary gland, and parietal cortex were 165824, 126688, and 161045 tags, respectively. This represented 59244, 45151, and 55131 distinct tags, respectively. Comparison of these mRNA profiles revealed that 22 mRNA species, including three potential novel transcripts, were preferentially expressed in the hypothalamus. In addition to well-known hypothalamic transcripts, such as hypocretin, several genes involved in hormone function, intracellular transduction, metabolism, protein transport, steroidogenesis, extracellular matrix, and brain disease were identified as preferentially expressed hypothalamic transcripts. In the pituitary gland, 106 mRNA species, including 60 potential novel transcripts, were preferentially expressed. In addition to well-known pituitary genes, such as growth hormone and thyroid stimulating hormone beta, a number of genes classified to function in transport, amino acid metabolism, intracellular transduction, cell adhesion, disulfide bond formation, stress response, transcription, protein synthesis, and turnover, cell differentiation, the cell cycle, and in the cytoskeleton and extracellular matrix were also preferentially expressed. In conclusion, the current study identified not only well-known hypothalamic and pituitary transcripts but also a number of new candidates likely to be involved in endocrine homeostatic systems regulated by the hypothalamus and pituitary gland.

  10. CHILDHOOD MALTREATMENT PREDICTS REDUCED INHIBITION-RELATED ACTIVITY IN THE ROSTRAL ANTERIOR CINGULATE IN PTSD, BUT NOT TRAUMA-EXPOSED CONTROLS.

    PubMed

    Stevens, Jennifer S; Ely, Timothy D; Sawamura, Takehito; Guzman, Dora; Bradley, Bekh; Ressler, Kerry J; Jovanovic, Tanja

    2016-07-01

    A deficit in the ability to inhibit fear has been proposed as a biomarker of posttraumatic stress disorder (PTSD). Previous research indicates that individuals with PTSD show reduced inhibition-related activation in rostral anterior cingulate cortex (rACC). The goal of the current study was to investigate differential influences of an early environmental risk factor for PTSD-childhood maltreatment-on inhibition-related brain function in individuals with PTSD versus trauma-exposed controls. Individuals with PTSD (n = 37) and trauma-exposed controls (n = 53) were recruited from the primary care waiting rooms of an urban public hospital in Atlanta, GA. Participants completed an inhibition task during fMRI, and reported childhood and adult traumatic experiences. The groups were matched for adult and child trauma load. We observed an interaction between childhood maltreatment severity and PTSD status in the rACC (P < .05, corrected), such that maltreatment was negatively associated with inhibition-related rACC activation in the PTSD group, but did not influence rACC activation in the TC group. Rostral ACC activation was associated with inhibition-related task performance in the TC group but not the PTSD group, suggesting a possible contribution to stress resilience. Findings highlight individual differences in neural function following childhood trauma, and point to inhibition-related activation in rostral ACC as a risk factor for PTSD. © 2016 Wiley Periodicals, Inc.

  11. Preclinical anti-cancer activity and multiple mechanisms of action of a cationic silver complex bearing N-heterocyclic carbene ligands.

    PubMed

    Allison, Simon J; Sadiq, Maria; Baronou, Efstathia; Cooper, Patricia A; Dunnill, Chris; Georgopoulos, Nikolaos T; Latif, Ayşe; Shepherd, Samantha; Shnyder, Steve D; Stratford, Ian J; Wheelhouse, Richard T; Willans, Charlotte E; Phillips, Roger M

    2017-09-10

    Organometallic complexes offer the prospect of targeting multiple pathways that are important in cancer biology. Here, the preclinical activity and mechanism(s) of action of a silver-bis(N-heterocyclic carbine) complex (Ag8) were evaluated. Ag8 induced DNA damage via several mechanisms including topoisomerase I/II and thioredoxin reductase inhibition and induction of reactive oxygen species. DNA damage induction was consistent with cytotoxicity observed against proliferating cells and Ag8 induced cell death by apoptosis. Ag8 also inhibited DNA repair enzyme PARP1, showed preferential activity against cisplatin resistant A2780 cells and potentiated the activity of temozolomide. Ag8 was substantially less active against non-proliferating non-cancer cells and selectively inhibited glycolysis in cancer cells. Ag8 also induced significant anti-tumour effects against cells implanted intraperitoneally in hollow fibres but lacked activity against hollow fibres implanted subcutaneously. Thus, Ag8 targets multiple pathways of importance in cancer biology, is less active against non-cancer cells and shows activity in vivo in a loco-regional setting. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  12. When and where does preferential flow matter - from observation to large scale modelling

    NASA Astrophysics Data System (ADS)

    Weiler, Markus; Leistert, Hannes; Steinbrich, Andreas

    2017-04-01

    Preferential flow can be of relevance in a wide range of soils and the interaction of different processes and factors are still difficult to assess. As most studies (including our own studies) focusing on the effect of preferential flow are based on relatively high precipitation rates, there is always the question how relevant preferential flow is under natural conditions, considering the site specific precipitation characteristics, the effect of the drying and wetting cycle on the initial soil water condition and shrinkage cracks, the site specific soil properties, soil structure and rock fragments, and the effect of plant roots and soil fauna (e.g. earthworm channels). In order to assess this question, we developed the distributed, process-based model RoGeR (Runoff Generation Research) to include a large number relevant features and processes of preferential flow in soils. The model was developed from a large number of process based research and experiments and includes preferential flow in roots, earthworm channels, along rock fragments and shrinkage cracks. We parameterized the uncalibrated model at a high spatial resolution of 5x5m for the whole state of Baden-Württemberg in Germany using LiDAR data, degree of sealing, landuse, soil properties and geology. As the model is an event based model, we derived typical event based precipitation characteristics based on rainfall duration, mean intensity and amount. Using the site-specific variability of initial soil moisture derived from a water balance model based on the same dataset, we simulated the infiltration and recharge amounts of all event classes derived from the event precipitation characteristics and initial soil moisture conditions. The analysis of the simulation results allowed us to extracts the relevance of preferential flow for infiltration and recharge considering all factors above. We could clearly see a strong effect of the soil properties and land-use, but also, particular for clay rich soils a

  13. Leveraging increased cytoplasmic nucleoside kinase activity to target mtDNA and oxidative phosphorylation in AML.

    PubMed

    Liyanage, Sanduni U; Hurren, Rose; Voisin, Veronique; Bridon, Gaëlle; Wang, Xiaoming; Xu, ChangJiang; MacLean, Neil; Siriwardena, Thirushi P; Gronda, Marcela; Yehudai, Dana; Sriskanthadevan, Shrivani; Avizonis, Daina; Shamas-Din, Aisha; Minden, Mark D; Bader, Gary D; Laposa, Rebecca; Schimmer, Aaron D

    2017-05-11

    Mitochondrial DNA (mtDNA) biosynthesis requires replication factors and adequate nucleotide pools from the mitochondria and cytoplasm. We performed gene expression profiling analysis of 542 human acute myeloid leukemia (AML) samples and identified 55% with upregulated mtDNA biosynthesis pathway expression compared with normal hematopoietic cells. Genes that support mitochondrial nucleotide pools, including mitochondrial nucleotide transporters and a subset of cytoplasmic nucleoside kinases, were also increased in AML compared with normal hematopoietic samples. Knockdown of cytoplasmic nucleoside kinases reduced mtDNA levels in AML cells, demonstrating their contribution in maintaining mtDNA. To assess cytoplasmic nucleoside kinase pathway activity, we used a nucleoside analog 2'3'-dideoxycytidine (ddC), which is phosphorylated to the activated antimetabolite, 2'3'-dideoxycytidine triphosphate by cytoplasmic nucleoside kinases. ddC is a selective inhibitor of the mitochondrial DNA polymerase γ. ddC was preferentially activated in AML cells compared with normal hematopoietic progenitor cells. ddC treatment inhibited mtDNA replication, oxidative phosphorylation, and induced cytotoxicity in a panel of AML cell lines. Furthermore, ddC preferentially inhibited mtDNA replication in a subset of primary human leukemia cells and selectively targeted leukemia cells while sparing normal progenitor cells. In animal models of human AML, treatment with ddC decreased mtDNA, electron transport chain proteins, and induced tumor regression without toxicity. ddC also targeted leukemic stem cells in secondary AML xenotransplantation assays. Thus, AML cells have increased cytidine nucleoside kinase activity that regulates mtDNA biogenesis and can be leveraged to selectively target oxidative phosphorylation in AML. © 2017 by The American Society of Hematology.

  14. Leveraging increased cytoplasmic nucleoside kinase activity to target mtDNA and oxidative phosphorylation in AML

    PubMed Central

    Liyanage, Sanduni U.; Hurren, Rose; Voisin, Veronique; Bridon, Gaëlle; Wang, Xiaoming; Xu, ChangJiang; MacLean, Neil; Siriwardena, Thirushi P.; Gronda, Marcela; Yehudai, Dana; Sriskanthadevan, Shrivani; Avizonis, Daina; Shamas-Din, Aisha; Minden, Mark D.; Bader, Gary D.; Laposa, Rebecca

    2017-01-01

    Mitochondrial DNA (mtDNA) biosynthesis requires replication factors and adequate nucleotide pools from the mitochondria and cytoplasm. We performed gene expression profiling analysis of 542 human acute myeloid leukemia (AML) samples and identified 55% with upregulated mtDNA biosynthesis pathway expression compared with normal hematopoietic cells. Genes that support mitochondrial nucleotide pools, including mitochondrial nucleotide transporters and a subset of cytoplasmic nucleoside kinases, were also increased in AML compared with normal hematopoietic samples. Knockdown of cytoplasmic nucleoside kinases reduced mtDNA levels in AML cells, demonstrating their contribution in maintaining mtDNA. To assess cytoplasmic nucleoside kinase pathway activity, we used a nucleoside analog 2′3′-dideoxycytidine (ddC), which is phosphorylated to the activated antimetabolite, 2′3′-dideoxycytidine triphosphate by cytoplasmic nucleoside kinases. ddC is a selective inhibitor of the mitochondrial DNA polymerase γ. ddC was preferentially activated in AML cells compared with normal hematopoietic progenitor cells. ddC treatment inhibited mtDNA replication, oxidative phosphorylation, and induced cytotoxicity in a panel of AML cell lines. Furthermore, ddC preferentially inhibited mtDNA replication in a subset of primary human leukemia cells and selectively targeted leukemia cells while sparing normal progenitor cells. In animal models of human AML, treatment with ddC decreased mtDNA, electron transport chain proteins, and induced tumor regression without toxicity. ddC also targeted leukemic stem cells in secondary AML xenotransplantation assays. Thus, AML cells have increased cytidine nucleoside kinase activity that regulates mtDNA biogenesis and can be leveraged to selectively target oxidative phosphorylation in AML. PMID:28283480

  15. Fucosylated chondroitin sulfate oligosaccharides exert anticoagulant activity by targeting at intrinsic tenase complex with low FXII activation: Importance of sulfation pattern and molecular size.

    PubMed

    Li, Junhui; Li, Shan; Yan, Lufeng; Ding, Tian; Linhardt, Robert J; Yu, Yanlei; Liu, Xinyue; Liu, Donghong; Ye, Xingqian; Chen, Shiguo

    2017-10-20

    Fucosylated chondroitin sulfates (fCSs) are structurally unusual glycosaminoglycans isolated from sea cucumbers that exhibit potent anticoagulant activity. These fCSs were isolated from sea cucumber, Isostichopus badionotus and Pearsonothuria graeffei. Fenton reaction followed by gel filtration chromatography afforded fCS oligosaccharides, with different sulfation patterns identified by mass and NMR spectroscopy, and these were used to clarify the relationship between the structures and the anticoagulant activities of fCSs. In vitro activities were measured by activated partial thromboplastin time (APTT), thrombin time (TT), thrombin and factor Xa inhibition, and activation of FXII. The results showed that free radicals preferentially acted on GlcA residues affording oligosaccharides that were purified from both fCSs. The inhibition of thrombin and factor X activities, mediated through antithrombin III and heparin cofactor II of fCSs oligosaccharides were affected by their molecular weight and fucose branches. Oligosaccharides with different sulfation patterns of the fucose branching had a similar ability to inhibit the FXa by the intrinsic factor Xase (factor IXa-VIIIa complex). Oligosaccharides with 2,4-O-sulfo fucose branches from fCS-Ib showed higher activities than ones with 3,4-O-disulfo branches obtained from fCS-Pg. Furthermore, a heptasaccharide is the minimum size oligosaccharide required for anticoagulation and FXII activation. This activity was absent for fCS oligosaccharides smaller than nonasaccharides. Molecular size and fucose branch sulfation are important for anticoagulant activity and reduction of size can reverse the activation of FXII caused by native fCSs. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Episodic Inhibition

    ERIC Educational Resources Information Center

    Racsmany, Mihaly; Conway, Martin A.

    2006-01-01

    Six experiments examined the proposal that an item of long-term knowledge can be simultaneously inhibited and activated. In 2 directed forgetting experiments items to-be-forgotten were found to be inhibited in list-cued recall but activated in lexical decision tasks. In 3 retrieval practice experiments, unpracticed items from practiced categories…

  17. Dithiocarbamates are teratogenic to developing zebrafish through inhibition of lysyl oxidase activity

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Boxtel, Antonius L. van, E-mail: thijs.van.boxtel@ivm.vu.n; Kamstra, Jorke H.; Fluitsma, Donna M.

    2010-04-15

    Dithiocarbamates (DTCs) are a class of compounds that are extensively used in agriculture as pesticides. As such, humans and wildlife are undoubtedly exposed to these chemicals. Although DTCs are thought to be relatively safe due to their short half lives, it is well established that they are teratogenic to vertebrates, especially to fish. In zebrafish, these teratogenic effects are characterized by distorted notochord development and shortened anterior to posterior axis. DTCs are known copper (Cu) chelators but this does not fully explain the observed teratogenic effects. We show here that DTCs cause malformations in zebrafish that highly resemble teratogenic effectsmore » observed by direct inhibition of a group of cuproenzymes termed lysyl oxidases (LOX). Additionally, we demonstrate that partial knockdown of three LOX genes, lox, loxl1 and loxl5b, sensitizes the developing embryo to DTC exposure. Finally, we show that DTCs directly inhibit zebrafish LOX activity in an ex vivo amine oxidase assay. Taken together, these results provide the first evidence that DTC induced teratogenic effects are, at least in part, caused by direct inhibition of LOX activity.« less

  18. Monoamine oxidase B (MAO-B) inhibition by active principles from Uncaria rhynchophylla.

    PubMed

    Hou, Wen-Chi; Lin, Rong-Dih; Chen, Cheng-Tang; Lee, Mei-Hsien

    2005-08-22

    Attenuation of monoamine oxidase B (MAO-B) activity may provide protection against oxidative neurodegeneration. For this reason, inhibition of MAO-B activity is used as part of the treatment of Parkinson's and Alzheimer's patients. The hook of Uncaria rhynchophylla (Miq.) Jacks. (Rubiaceae) is a traditional Chinese herbal drug that is generally used to treat convulsive disorders. In this study, the fractionation and purification of Uncaria rhynchophylla extracts using a bioguided assay isolated two known compounds, (+)-catechin and (-)-epicatechin. The compounds inhibited MAO-B, as measured by an assay of rat brain MAO-B separated by electrophoresis on a 7.5% native polyacrylamide gel. The IC(50) values of (+)-catechin and (-)-epicatechin were 88.6 and 58.9 microM, respectively, and inhibition occurred in a dose-dependent manner, as measured by the fluorescence method. The Lineweaver-Burk plot revealed K(i) values for (+)-catechin and (-)-epicatechin of 74 and 21 microM, respectively. This suggests that these two compounds, isolated here for the first time from Uncaria rhynchophylla, might be able to protect against neurodegeneration in vitro, and, therefore, the molecular mechanism deserves further study. This finding may also increase interest in the health benefits of Uncaria rhynchophylla.

  19. Which key properties controls the preferential transport in the vadose zone under transient hydrological conditions

    NASA Astrophysics Data System (ADS)

    Groh, J.; Vanderborght, J.; Puetz, T.; Gerke, H. H.; Rupp, H.; Wollschlaeger, U.; Stumpp, C.; Priesack, E.; Vereecken, H.

    2015-12-01

    Understanding water flow and solute transport in the unsaturated zone is of great importance for an appropriate land use management strategy. The quantification and prediction of water and solute fluxes through the vadose zone can help to improve management practices in order to limit potential risk on our fresh water resources. Water related solute transport and residence time is strongly affected by preferential flow paths in the soil. Water flow in soils depends on soil properties and site factors (climate or experiment conditions, land use) and are therefore important factors to understand preferential solute transport in the unsaturated zone. However our understanding and knowledge of which on-site properties or conditions define and enhance preferential flow and transport is still poor and mostly limited onto laboratory experimental conditions (small column length and steady state boundary conditions). Within the TERENO SOILCan lysimeter network, which was designed to study the effects of climate change on soil functions, a bromide tracer was applied on 62 lysimeter at eight different test sites between Dec. 2013 and Jan. 2014. The TERENO SOILCan infrastructure offers the unique possibility to study the occurrence of preferential flow and transport of various soil types under different natural transient hydrological conditions and land use (crop, bare and grassland) at eight TERENO SOILCan observatories. Working with lysimeter replicates at each observatory allows defining the spatial variability of preferential transport and flow. Additionally lysimeters in the network were transferred within and between observatories in order to subject them to different rainfall and temperature regimes and enable us to relate the soil type susceptibility of preferential flow and transport not only to site specific physical and land use properties, but also to different transient boundary conditions. Comparison and statistical analysis between preferential flow indicators 5

  20. [Inhibition rate of gamma-aminolevulinic acid dehydratase activity in erythrocytes as a reliable index for individual workers of low lead exposure].

    PubMed

    Hirano, H; Omichi, M; Ohishi, H; Ishikawa, K; Hirashima, N

    1983-09-01

    As the delta-aminolevulinic acid dehydratase (ALAD) activity in erythrocytes is decreased by lead exposure, we considered that a net reduction of ALAD activity by lead in blood should be the difference between the activity fully activated with zinc (Zn2+) and dithiothreitol (DTT) and that without activation. The optimal condition of activation of ALAD was found by addition of 0.25 mM of Zn2+ and 10 mM of DTT in the reaction mixture. Judging from our previous results that the amount of inhibition of ALAD activity can be represented as the rate of inhibition and is closely correlated with the dose of lead administered to rabbits, the inhibition rate of ALAD activity and lead content in blood (Pb-B) of lead workers were measured. The scatter diagram obtained from the inhibition rate and lead content in blood has two groups being divided at 50 micrograms/ml of Pb-B. In one group less than 50 micrograms/100 ml of Pb-B, the inhibition rate has been closely related to Pb-B., the regression equation being Y = 1.82 X + 11.7, and the correlation coefficient + 0.926. In another group more than 50 micrograms/100 ml of Pb-B the inhibition rate remained constant at the 90% level. Measurement of the inhibition rate suggests to have practical validity for monitoring lead exposure in workers, and by means of a nomograph lead content in blood can be estimated from the inhibition rate.