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Sample records for puva inhibits degranulation

  1. Inhibition of rat mast cell degranulation and histamine release by histamine-rat gammaglobulin conjugate.

    PubMed

    Ishikawa, T; Shimada, T; Kessoku, N; Kiyoi, M

    1979-01-01

    Histamin-rat-gamma-globulin conjugate inhibited degranulation and histamine release of rat peritoneal mast cells to a greater extent than the rat globulin or histamine alone. Since mast cells contain histamine receptors, it may be assumed that the histamine bound to the gamma-globulin combines with the rat mast cell histamine receptor and inhibits the degranulation and histamine release by a feedback mechanism. PMID:87381

  2. Gangliosides inhibit bee venom melittin cytotoxicity but not phospholipase A{sub 2}-induced degranulation in mast cells

    SciTech Connect

    Nishikawa, Hirofumi; Kitani, Seiichi

    2011-05-01

    Sting accident by honeybee causes severe pain, inflammation and allergic reaction through IgE-mediated anaphylaxis. In addition to this hypersensitivity, an anaphylactoid reaction occurs by toxic effects even in a non-allergic person via cytolysis followed by similar clinical manifestations. Auto-injectable epinephrine might be effective for bee stings, but cannot inhibit mast cell lysis and degranulation by venom toxins. We used connective tissue type canine mast cell line (CM-MC) for finding an effective measure that might inhibit bee venom toxicity. We evaluated degranulation and cytotoxicity by measurement of {beta}-hexosaminidase release and MTT assay. Melittin and crude bee venom induced the degranulation and cytotoxicity, which were strongly inhibited by mono-sialoganglioside (G{sub M1}), di-sialoganglioside (G{sub D1a}) and tri-sialoganglioside (G{sub T1b}). In contrast, honeybee venom-derived phospholipase A{sub 2} induced the net degranulation directly without cytotoxicity, which was not inhibited by G{sub M1}, G{sub D1a} and G{sub T1b}. For analysis of distribution of G{alpha}{sub q} and G{alpha}{sub i} protein by western blotting, lipid rafts were isolated by using discontinuous sucrose gradient centrifuge. Melittin disrupted the localization of G{alpha}{sub q} and G{alpha}{sub i} at lipid raft, but gangliosides stabilized the rafts. As a result from this cell-based study, bee venom-induced anaphylactoid reaction can be explained with melittin cytotoxicity and phospholipase A{sub 2}-induced degranulation. Taken together, gangliosides inhibit the effect of melittin such as degranulation, cytotoxicity and lipid raft disruption but not phospholipase A{sub 2}-induced degranulation in mast cells. Our study shows a potential of gangliosides as a therapeutic tool for anaphylactoid reaction by honeybee sting.

  3. Degranulation of mast cells and inhibition of the response to secretory agents by phototoxic compounds and ultraviolet radiation

    SciTech Connect

    Gendimenico, G.J.; Kochevar, I.E.

    1984-11-01

    The symptoms of cutaneous phototoxicity from coal tar compounds and the nonsteroidal anti-inflammatory drug benoxaprofen are characterized by wheal and flare formation which is mediated by histamine released from dermal mast cells. Rat serosal mast cells were used as an in vitro model system to study the direct effect of phototoxic compounds on mast cell degranulation. The coal tar compounds studied included acridine and pyrene. Combined exposure of cells to acridine and UVA (320 to 400 nm) radiation caused mast cells to degranulate, as assayed by the release of (/sup 3/H)serotonin. Maximum (/sup 3/H)serotonin release (70 to 80%) was obtained with 50 microM acridine and 300 kJ/m2 UVA. Pyrene (25 microM), when photoexcited with UVB (280 to 360 nm) radiation, caused about 80% release of (/sup 3/H)serotonin. No degranulation occurred with 20 microM benoxaprofen and UVB doses up to 7.2 kJ/m2. Trypan blue staining correlated well with degranulation caused by acridine plus UVA; however, with pyrene plus UVB there was greater (/sup 3/H)serotonin release than dye uptake. Excitation of photosensitizers with doses of UV radiation that did not cause trypan blue staining suppressed degranulation of mast cells in response to chemical stimulation. Acridine, pyrene, and benoxaprofen in the presence of UV radiation inhibited the mast cells from responding to compound 48/80 or the calcium ionophore, chlortetracycline. Two other phototoxic compounds, chlorpromazine and deoxytetracycline, also abolished degranulation by compound 48/80. These findings indicate that phototoxic compounds: (1) cause degranulation in the presence of high doses of UV radiation; and (2) suppress degranulation of mast cells in response to secretory stimuli at doses of UV radiation that do not cause release of mediator.

  4. Hydroxytyrosol and oleuropein of olive oil inhibit mast cell degranulation induced by immune and non-immune pathways.

    PubMed

    Persia, Fabio Andrés; Mariani, María Laura; Fogal, Teresa Hilda; Penissi, Alicia Beatriz

    2014-09-25

    The aim of this study was to determine whether hydroxytyrosol and oleuropein, the major phenols found in olives and olive oil, inhibit mast cell activation induced by immune and non-immune pathways. Purified peritoneal mast cells were preincubated in the presence of test compounds (hydroxytyrosol or oleuropein), before incubation with concanavalin A, compound 48/80 or calcium ionophore A23187. Dose-response and time-dependence studies were carried out. Comparative studies with sodium cromoglycate, a classical mast cell stabilizer, were also made. After incubation the supernatants and pellets were used to determine the ?-hexosaminidase content by colorimetric reaction. The percentage of ?-hexosaminidase release in each tube was calculated and taken as a measure of mast cell activation. Other samples of cell pellets were used for cell viability studies by the trypan blue dye exclusion test, or fixed for light and electron microscopy. Biochemical and morphological findings of the present study showed for the first time that hydroxytyrosol and oleuropein inhibit mast cell degranulation induced by both immune and non-immune pathways. These results suggest that olive phenols, particularly hydroxytyrosol and oleuropein, may provide insights into the development of useful tools for the prevention and treatment of mast cell-mediated disorders. PMID:25007967

  5. Nicotine Inhibits Fc?RI-induced Cysteinyl Leukotrienes and Cytokine Production without Affecting Mast Cell Degranulation Through Alpha7/Alpha9/Alpha10-nicotinic Receptors1

    PubMed Central

    Mishra, Neerad C.; Rir-sima-ah, Jules; Boyd, R. Thomas; Singh, Shashi P.; Gundavarapu, Sravanthi; Langley, Raymond J.; Razani-Boroujerdi, Seddigheh; Sopori, Mohan L

    2010-01-01

    Smokers are less likely to develop some inflammatory and allergic diseases. In Brown-Norway rats, nicotine inhibits several parameters of allergic asthma including the production of Th2 cytokines and the cysteinyl leukotriene LTC4. Cysteinyl leukotrienes are primarily produced by mast cells, and these cells play a central role in allergic asthma. Mast cells express a high affinity receptor for IgE (Fc?RI). Following its cross-linking, cells degranulate and release preformed inflammatory mediators (early phase), and synthesize and secrete cytokines/chemokines and leukotrienes (late phase). The mechanism by which nicotine modulates mast cell activation is unclear. Using ?-bungarotoxin binding, qPCR, and PCR product sequencing, we show that the rat mast/basophil cell line RBL-2H3 express nicotinic acetylcholine receptors (nAChRs) ?7, ?9, and ?10, and exposure to exceedingly low concentrations of nicotine (nanomolar), but not the biologically inactive metabolite cotinine for ?8h suppressed the late phase (leukotriene/cytokine production) but not degranulation (histamine and hexosaminidase release). These effects were unrelated to those of nicotine on intracellular free calcium concentration but causally associated with the inhibition of cPLA2 activity and PI3K/ERK/NF-?B pathway, including phosphorylation of Akt and ERK, and nuclear translocation of NF-?B. The suppressive effect of nicotine on the late-phase response was blocked by the ?7/?9-nAChRs antagonist methyllycaconitine and ?-bungarotoxin, and by siRNA knockdown of ?7, ?9, or ?10 nAChRs, suggesting a functional interaction between ?7, ?9, and ?10 nAChRs that might explain the response of RBL to nanomolar concentrations of nicotine. This “hybrid” receptor might serve as a target for novel anti-allergic/asthmatic therapies. PMID:20505147

  6. Cardiovascular stress of photochemotherapy (PUVA)

    SciTech Connect

    Ciafone, R.A.; Rhodes, A.R.; Audley, M.; Freedberg, I.M.; Abelmann, W.H.

    1980-11-01

    The recently devised therapy for psoriasis and related skin diseases, consisting of long-wave ultraviolet light and oral 8-methoxypsoralen (PUVA), was investigated for its cardiovascular effects. In seventeen patients, long-wave ultraviolet light therapy in a treatment enclosure (mean duration, 19.3 minutes) resulted in ambient temperatures of 39.2 degrees C +/- 2.1 degrees C (SD) and skin temperatures of 38.2 degrees C +/- 1.4 degrees C. In upright subjects, heart rate rose 30.8% to 114.4 +/- 25.2 beats per minute (bpm). Intensive room air conditioning, outside of the treatment enclosure, although significantly lowering skin and ambient temperatures, did not affect the heart rates significantly. PUVA therapy is associated with a definite cardiovascular stress when the box type of therapeutic unit is used. Possible modifications are discussed.

  7. Gene expression profiling reveals the role of RIG1 like receptor signaling in p53 dependent apoptosis induced by PUVA in keratinocytes.

    PubMed

    Chowdhari, Shruti; Saini, Neeru

    2016-01-01

    Photochemotherapy using 8-methoxypsoralen in combination with UVA radiation (PUVA) is an effective treatment for various skin dermatosis including psoriasis however its molecular mechanism is not clear. Previously we demonstrated that PUVA differentially regulates miRNA expression profile with a significant up-regulation of hsa-miR-4516. To study in detail the molecular mechanism of PUVA in keratinocytes, we investigated the genome wide transcriptomic changes using Illumina whole genome gene expression beadchip. Microarray analysis revealed 1932 differentially expressed gene and their Insilico analysis revealed Retinoic Acid Inducible Gene-I (RIG-1) signaling, apoptosis and p53 pathway to be associated with PUVA induced effects. We demonstrate that miR-4516 mediated down-regulation of UBE2N promotes p53 nuclear translocation and pro-apoptotic activity of PUVA is independent of IRF3 but is mediated by the RIG-I in a p53 and NF?B dependent manner. Additionally, PUVA inactivated the AKT/mTOR pathway in concert with inhibition of autophagy and suppressed cell migration. Taken together this study broadens our understanding about the mechanism of action of PUVA providing possible new strategy targeting proapoptotic function of RIG-1, a regulator of innate immune response or p53 for psoriasis therapy. PMID:26518362

  8. Effects of PUVA on the eye

    SciTech Connect

    Backman, H.A.

    1982-01-01

    Psoriasis is a common skin disease which may be treated with 8-methoxy psoralen and long-wave ultraviolet light (PUVA). Eye protection is provided during and after treatment to prevent the development of photokeratitis and cataracts. Fifteen patients, treated with medication and ultraviolet A (UVA) had an initial complete eye examination and a repeat examination after each treatment. No patients developed cataracts but almost one-half of the patients had a mild form of photokeratoconjunctivitis. The ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye ocular manifestations included photophobia, conjunctivitis, keratitis, and dry eyes. Tear break-up time was reduced significantly immediately after treatment for two patients but returned to normal 8 hr later. Dermatologists who employ PUVA treatments should be concerned about photokeratoconjunctivitis and the dry-eye syndrome.

  9. Cytochrome P450 CYP1B1 Interacts with 8-Methoxypsoralen (8-MOP) and Influences Psoralen-Ultraviolet A (PUVA) Sensitivity

    PubMed Central

    Deeni, Yusuf Y.; Ibbotson, Sally H.; Woods, Julie A.; Wolf, C. Roland; Smith, Gillian

    2013-01-01

    Background There are unpredictable inter-individual differences in sensitivity to psoralen-UVA (PUVA) photochemotherapy, used to treat skin diseases including psoriasis. Psoralens are metabolised by cytochrome P450 enzymes (P450), and we hypothesised that variability in cutaneous P450 expression may influence PUVA sensitivity. We previously showed that P450 CYP1B1 was abundantly expressed in human skin and regulated by PUVA, and described marked inter-individual differences in cutaneous CYP1B1 expression. Objectives We investigated whether CYP1B1 made a significant contribution to 8-methoxypsoralen (8-MOP) metabolism, and whether individuality in CYP1B1 activity influenced PUVA sensitivity. Methods We used E. coli membranes co-expressing various P450s and cytochrome P450 reductase (CPR) to study 8-MOP metabolism and cytotoxicity assays in CYP1B1-expressing mammalian cells to assess PUVA sensitivity. Results We showed that P450s CYP1A1, CYP1A2, CYP1B1, CYP2A6 and CYP2E1 influence 8-MOP metabolism. As CYP1B1 is the most abundant P450 in human skin, we further demonstrated that: (i) CYP1B1 interacts with 8-MOP (ii) metabolism of the CYP1B1 substrates 7-ethoxyresorufin and 17-?-estradiol showed concentration-dependent inhibition by 8-MOP and (iii) inhibition of 7-ethoxyresorufin metabolism by 8-MOP was influenced by CYP1B1 genotype. The influence of CYP1B1 on PUVA cytotoxicity was further investigated in a Chinese hamster ovary cell line, stably expressing CYP1B1 and CPR, which was more sensitive to PUVA than control cells, suggesting that CYP1B1 metabolises 8-MOP to a more phototoxic metabolite(s). Conclusion Our data therefore suggest that CYP1B1 significantly contributes to cutaneous 8-MOP metabolism, and that individuality in CYP1B1 expression may influence PUVA sensitivity. PMID:24086543

  10. A novel inhaled Syk inhibitor blocks mast cell degranulation and early asthmatic response.

    PubMed

    Ramis, Isabel; Otal, Raquel; Carreño, Cristina; Domènech, Anna; Eichhorn, Peter; Orellana, Adelina; Maldonado, Mónica; De Alba, Jorge; Prats, Neus; Fernández, Joan-Carles; Vidal, Bernat; Miralpeix, Montserrat

    2015-09-01

    Spleen tyrosine kinase (Syk) is essential for signal transduction of immunoreceptors. Inhibition of Syk abrogates mast cell degranulation and B cell responses. We hypothesized that Syk inhibition in the lung by inhaled route could block airway mast cells degranulation and the early asthmatic response without the need of systemic exposure. We discovered LAS189386, a novel Syk inhibitor with suitable properties for inhaled administration. The aim of this study was to characterize the in vitro and in vivo profile of LAS189386. The compound was profiled in Syk enzymatic assay, against a panel of selected kinases and in Syk-dependent cellular assays in mast cells and B cells. Pharmacokinetics and in vivo efficacy was assessed by intratracheal route. Airway resistance and mast cell degranulation after OVA challenge was evaluated in an ovalbumin-sensitized Brown Norway rat model. LAS189386 potently inhibits Syk enzymatic activity (IC50 7.2 nM), Syk phosphorylation (IC50 41 nM), LAD2 cells degranulation (IC50 56 nM), and B cell activation (IC50 22 nM). LAS189386 inhibits early asthmatic response and airway mast cell degranulation without affecting systemic mast cells. The present results support the hypothesis that topical inhibition of Syk in the lung, without systemic exposure, is sufficient to inhibit EAR in rats. Syk inhibition by inhaled route constitutes a promising therapeutic option for asthma. PMID:26051661

  11. Influence of PUVA and UVB radiation on delayed hypersensitivity in the guinea pig

    SciTech Connect

    Morison, W.L.; Parrish, J.A.; Woehler, M.E.; Krugler, J.I.; Bloch, K.J.

    1981-06-01

    Exposure of guinea pigs to UVA (320--400 nm) radiation following administration of 8-methoxypsoralen by gavage (referred to by the acronym, PUVA) or exposure to UVB (290--320 nm) radiation, produced suppression of the cutaneous delayed hypersensitivity reaction at the site of exposure to radiation and at distant nonexposed sites. In these experiments, the animals were immunized by injection of dinitrophenyl-bovine gamma-globulin (DNP-BGG) in complete Freund's adjuvant and delayed hypersensitivity responses were provoked by intradermal injections of DNP-BGG, DNP and BGG on the flanks. Exposure to erythemogenic doses of either PUVA or UVB radiation for 7 days prior to immunization and for the 7 days between immunization and challenge (total period of radiation: 14 days) produced inhibiton of responses to each of the test substances. In addition, treatment with erythemogenic doses of PUVA either for 7 days prior to immunization or during the interval between immunization and challenge with DNP-BGG, inhibited the delayed hypersensitivity responses at the site of irradiation and at a nonexposed site. These findings suggest that in vivo exposure to nonionizing radiation leads to both local and systemic alteration of certain immune responses.

  12. Microvascular leakage of plasma proteins after PUVA and UVA

    SciTech Connect

    Staberg, B.; Worm, A.M.; Rossing, N.; Brodthagen, H.

    1982-04-01

    The transcapillary escape rate of albumin (TERalb), is a parameter of the leakage of macromolecules from the total microvasculature. In patients with psoriasis short-term PUVA treatment induces an increase in TERalb. In this study TERalb was measured in 3 groups of normal humans treated with PUVA, UVA and 8-methoxypsoralen. Treatment with PUVA and UVA caused a statistically significant increase in TERalb, whereas treatment with 8-methoxypsoralen did not induce any measurable changes. It is concluded that the UVA irradiation causes the abnormal leakage of macromolecules, whereas psoralen is not the responsible component. Furthermore the phenomenon can be elicited in normals and is not based on a preexisting psoriasis.

  13. PUVA: A Monte Carlo code for intra-articular PUVA treatment of arthritis

    SciTech Connect

    Descalle, M.A.; Laing, T.J.; Martin, W.R.

    1996-12-31

    Current rheumatoid arthritis treatments are only partially successful. Intra-articular psoralen-ultraviolet light (PUVA) phototherapy appears to be a new and valid alternative. Ultraviolet laser light (UVA) delivered in the knee joint through a fiber optic is used in combination with 8-methoxypsoralen (8-MOP), a light-sensitive chemical administered orally. A few hours after ingestion, the psoralen has diffused in all body cells. Once activated by UVA light, it binds to biological molecules, inhabiting cell division and ultimately causing local control of the arthritis. The magnitude of the response is proportional to the number of photoproducts delivered to tissues (i.e., the number of absorbed photons): the PUVA treatment will only be effective if a sufficient and relatively uniform dose is delivered to the diseased synovial tissues, while sparing other tissues such as cartilage. An application is being developed, based on analog Monte Carlo methods, to predict photon densities in tissues and the minimum number of intra-articular catheter positions necessary to ensure proper treatment of the diseased zone. Other interesting aspects of the problem deal with the compexity of the joint geometry, the physics of light scattering in tissues (a relatively new field of research that is not fully understood because of the variety of tissues and tissue components), and, finally, the need to include optic laws (reflection and refraction) at interfaces.

  14. Effect of Pakistani medicinal plants on IgE/antigen- and ionophore-induced mucosal mast cells degranulation.

    PubMed

    Zaidi, Syed Faisal; Kim, Ji-Hyun; Tomoe, Yashiro; Usmanghani, Khan; Kadowaki, Makoto

    2014-07-01

    Cumulative evidence has now demonstrated the stimulation of mucosal mast cells by both allergic and non-allergic triggers and their inhibition as a potential therapeutic target in many diseases like food allergy and ulcerative colitis. Hence, we screened medicinal plants from Pakistan against antigen- and ionophore-induced degranulation of mucosal mast cells. Aqueous ethanol extracts were screened. IgE/antigen- and A23187-induced degranulation of mucosal-type murine bone marrow derived mast cells (mBMMCs) were screening assays and ?-hexosaminidase released from degranulated mBMMCs was measured. Real time-polymerase chain reaction was employed to examine the expression of TNF-? and IL-4 mRNA. Acetoxychavicol acetate, was examined by degranulation assays and real time-PCR. Among the ten plants screened against IgE/antigen stimulated degranulation, five plants; Alpinia galangal, Mentha arvensis, Myrtus communis, Polygonum bistorta and Syzygium aromaticum demonstrated significant (p<0.01) suppression of the degranulation at 100 ?g/ml. Of them, Alpinia galangal showed significant (p<0.01) inhibition at 32 mg/ml. In A23187-induced degranulation, all plants showed significant (p<0.01) inhibition at 100 ?g/ml except Tamarix dioica. Again Alpinia galangal exhibited significant (p<0.01) suppression at 32 ?g/ml. In a concentration dependent assay, Alpinia galangal revealed significant suppression at 10 ?g/ml against A23187-stimulated degranulation. Acetoxychavicol acetate demonstrated significant (p<0.01) inhibition at 3.2 ?M in IgE/antigen-treated cells and at 10 ?M in A23187-treated cells. Furthermore, both Alpinia galangal and acetoxychavicol acetate suppressed the IgE/antigen- and A23187-enhanced mRNA expression of inflammatory cytokines, TNF-a and IL-4, in mBMMCs. Our findings revealed the suppressive effect of Alpinia galangal and acetoxychavicol acetate on degranulation of mBMMCs by allergic and non-allergic stimuli, which can be utilized for future drug development against food allergy or ulcerative colitis. PMID:25016264

  15. Effect of fruits of Opuntia elatior Mill on mast cell degranulation

    PubMed Central

    Chauhan, Sanjay P.; Sheth, N. R.; Suhagia, B. N.

    2015-01-01

    Background: The presence of potentially active nutrients and their multifunctional properties make prickly pear a perfect candidate for the production of phytopharmaceutical products. Among the numerous Opuntia species, bioactive compounds have been isolated and characterized primarily from Opuntia ficus-indica, Opuntia polycantha, Opuntia stricta, Opuntia dilleni for various medicinal properties. Objective: Based on the traditional use of prickly pear for enhancement of immune function, the objective of the present study to evaluate the effect of prickly pear on mast cell degranulation function. Materials and Methods: The Opuntia fruit juice (OFJ) (10-200 ?l/ml) were studied for the effect on sensitized rat peritoneal mast cell degranulation induced by immunological (egg albumin), and nonimmunological (compound 48/80) stimuli and compared with that of the reference standard, sodium cromoglycate and ketotifen (10 ?g/ml). Results and Conclusion: The OFJ exhibited significantly (P < 0.001) concentration dependent inhibition of mast cell degranulation. The IC50 value of OFJ was found 12.24 and 18 ?l/ml for immunological and nonimmunological induced mast cell degranulation, respectively. The betacyanin is an active principle compound in prickly pear that may responsible for mast cell stabilizing action. PMID:25883521

  16. Modulation of Basophils' Degranulation and Allergy-Related Enzymes by Monomeric and Dimeric Naphthoquinones

    PubMed Central

    Pinho, Brígida R.; Sousa, Carla; Valentão, Patrícia; Oliveira, Jorge M. A.; Andrade, Paula B.

    2014-01-01

    Allergic disorders are characterized by an abnormal immune response towards non-infectious substances, being associated with life quality reduction and potential life-threatening reactions. The increasing prevalence of allergic disorders demands for new and effective anti-allergic treatments. Here we test the anti-allergic potential of monomeric (juglone, menadione, naphthazarin, plumbagin) and dimeric (diospyrin and diosquinone) naphthoquinones. Inhibition of RBL-2H3 rat basophils' degranulation by naphthoquinones was assessed using two complementary stimuli: IgE/antigen and calcium ionophore A23187. Additionally, we tested for the inhibition of leukotrienes production in IgE/antigen-stimulated cells, and studied hyaluronidase and lipoxidase inhibition by naphthoquinones in cell-free assays. Naphthazarin (0.1 µM) decreased degranulation induced by IgE/antigen but not A23187, suggesting a mechanism upstream of the calcium increase, unlike diospyrin (10 µM) that reduced degranulation in A23187-stimulated cells. Naphthoquinones were weak hyaluronidase inhibitors, but all inhibited soybean lipoxidase with the most lipophilic diospyrin, diosquinone and menadione being the most potent, thus suggesting a mechanism of competition with natural lipophilic substrates. Menadione was the only naphthoquinone reducing leukotriene C4 production, with a maximal effect at 5 µM. This work expands the current knowledge on the biological properties of naphthoquinones, highlighting naphthazarin, diospyrin and menadione as potential lead compounds for structural modification in the process of improving and developing novel anti-allergic drugs. PMID:24587235

  17. Treatment of chronic graft-versus-host disease with ultraviolet irradiation and psoralen (PUVA).

    PubMed

    Vogelsang, G B; Wolff, D; Altomonte, V; Farmer, E; Morison, W L; Corio, R; Horn, T

    1996-06-01

    Chronic graft-versus-host disease (GVHD) remains a difficult clinical problem to treat and manage. We have reviewed our treatment of 40 patients treated at a single institution with PUVA (ultraviolet irradiation and psoralen) over a 14 year period. Thirty-five patients were treated for refractory chronic GVHD and five patients were treated at presentation of high-risk chronic GVHD. Overall, 31 of 40 patients improved on PUVA treatment. Sixteen patients achieved a complete response to PUVA added to their GVHD regimen. Four of the 15 partial responders had complete resolution of cutaneous GVHD but persistence of other systemic manifestations. The remaining partial responders had at least a 50% improvement in GVHD. We have also used PUVA with a glass fiber extension to treat intra-oral GVHD. PUVA is well tolerated with a high rate of response in the skin and mild side effects except for three patients who had therapy discontinued after phototoxicity (burn). PMID:8807115

  18. Imperatorin Suppresses Degranulation and Eicosanoid Generation in Activated Bone Marrow-Derived Mast Cells

    PubMed Central

    Jeong, Kyu-Tae; Lee, Eujin; Park, Na-Young; Kim, Sun-Gun; Park, Hyo-Hyun; Lee, Jiean; Lee, Youn Ju; Lee, Eunkyung

    2015-01-01

    Imperatorin has been known to exert many biological functions including anti-inflammatory activity. In this study, we investigated the inhibitory effects of imperatorin on the production of inflammatory mediators in mouse bone marrow-derived mast cells (BMMC). Imperatorin inhibited degranulation and the generation of eicosanoids (leukotriene C4 (LTC4) and prostaglandin D2 (PGD2)) in IgE/antigen (Ag)-stimulated BMMC. To elucidate the molecular mechanism involved in this process, we investigated the effect of imperatorin on intracellular signaling in BMMC. Biochemical analyses of the IgE/Ag-mediated signaling pathway demonstrated that imperatorin dramatically attenuated degranulation and the production of 5-lipoxygenase-dependent LTC4 and cyclooxygenase-2-dependent PGD2 through the inhibition of intracellular calcium influx/phospholipase C?1, cytosolic phospholipase A2/mitogen-activated protein kinases and/or nuclear factor-?B pathways in BMMC. These results suggest that the effects of imperatorin on inhibition of degranulation and eicosanoid generation through the suppression of multiple steps of IgE/Ag-mediated signaling pathways would be beneficial for the prevention of allergic inflammation. PMID:26336581

  19. PUVA treatment in chromium hypersensitivity: effect on skin reactivity and lymphocyte functions.

    PubMed

    Jansén, C T; Viander, M; Kalimo, K; Soppi, A M; Soppi, E

    1981-01-01

    Two male patients with longstanding contact sensitivity to chromium were treated with PUVA. One patient, suffering from concomitant photosensitivity, reacted very favorably; his skin lesions cleared and light tolerance increased. This was paralleled by a decrease in the photopatch test reactivity and by the extinction of the patch-test reactivity on PUVA-exposed (pigmented) skin. Patch and photopatch tests on PUVA-shielded skin showed no decrease in skin test reactivity. PUVA-treatment caused a decrease in the number of rosette-forming T cells and an increase in lymphocyte stimulation in both patients. In one patient, abnormally high PHA-induced suppressor cell activities were recorded prior to treatment; after PUVA therapy the values were back to normal. In both patients, the PPD-induced suppressor cell activity of PWN response was clearly increased by PUVA-therapy. Other suppressor cell functions were not much affected. It is concluded that while PUVA-therapy may produce some systemic immunological effects, its abating effect on contact sensitivity and photosensitivity is mainly mediated through local mechanisms in the skin. PMID:7271310

  20. hsa-miR-4516 mediated downregulation of STAT3/CDK6/UBE2N plays a role in PUVA induced apoptosis in keratinocytes.

    PubMed

    Chowdhari, Shruti; Saini, Neeru

    2014-11-01

    Psoriasis is a chronic inflammatory skin disorder mediated by cross-talk occurring between epidermal keratinocytes, dermal vascular cells and immunocytes. Literature reveals that Signal transducer and activator of transcription 3 (STAT3), a protein involved in transmitting extracellular signals to the nucleus, is a possible important link between keratinocytes and immunocytes and is crucial to the development of psoriasis. Although photochemotherapy using UV in combination with 8 methoxypsoralen is one of the most effective therapy for moderate to severe plaque psoriasis, its mechanism of action is largely unknown. Herein, we studied the change in miRNA profiles of cultured human keratinocytes (HaCaT cells) before and after in vitro PUVA treatment by 8 methoxypsoralen and found significant up regulation of hsa-miR-4516. We for the first time demonstrate that ectopic expression of hsa-miR-4516 directly targets STAT3 protein by binding to its 3'UTR in HaCaT cells as confirmed by Luciferase reporter assays and Western blot analysis. We further show that overexpression of hsa-miR-4516 downregulates STAT3, p-STAT3, CDK6, and UBE2N proteins that are consistently upregulated in psoriasis and induces apoptosis in HaCaT cells. We also observed that anti-miR-4516 treatment was able to partially inhibit PUVA-induced apoptosis, suggesting that miR-4516 is involved in PUVA-induced apoptosis. Taken together, these results not only indicate the mechanistic involvement of hsa-miR-4516 in PUVA mediated effects by down-regulating STAT3 in HaCaT keratinocytes, but also highlight the potential of hsa-miR-4516 in development of novel therapeutic strategies. J. Cell. Physiol. 229: 1630-1638, 2014. © 2014 Wiley Periodicals, Inc. PMID:24610393

  1. Neutrophil degranulation by Helicobacter pylori proteins.

    PubMed Central

    Nøorgaard, A; Andersen, L P; Nielsen, H

    1995-01-01

    Mucosal biopsy specimens from patients with Helicobacter pylori infection in gastric antrum contain an increased amount of myeloperoxidase. This study was performed to elucidate the interaction of H pylori sonicate protein(s) and neutrophils concerning myeloperoxidase release. Neutrophil degranulation with myeloperoxidase release was examined in a direct stimulating assay. Priming activity of H pylori was examined after preincubating neutrophils in sonicate, either crude or modified by heat treatment, pronase inactivation and dialysis, and stimulating with N-formyl-methionyl-leucyl-phenylalanine (fMLP) or serum opzonised zymosan (OZ). It was found that H pylori sonicate protein(s) stimulates neutrophil degranulation with myeloperoxidase release in a concentration dependent way. The activity was distinct from fMLP and capable of priming the subsequent fMLP and OZ response. Experiments with the modified bacterial sonicate suggest the activity is caused by a protein, but the findings show that non-protein molecules, for example, lipopolysaccarides were also part of the H pylori sonicate priming activity. The increased mucosal myeloperoxidase in H pylori associated disease can be a direct consequence of bacteria derived stimulation of inflammatory neutrophils. PMID:7698692

  2. Triggering of degranulation in mast cells by exogenous type II phospholipase A2.

    PubMed

    Murakami, M; Hara, N; Kudo, I; Inoue, K

    1993-11-15

    We have previously shown the possibility that endogenous type II phospholipase A2 (PLA2) might participate in degranulation in mast cells (MC) (Murakami, M., et al. 1992. Eur. J. Biochem. 209:257). Now we have examined whether or not exogenously added type II PLA2 triggers MC degranulation. When rat peritoneal connective tissue MC (CTMC) were exposed to purified rat type II PLA2 at concentrations of more than 10 micrograms/ml, significant release of histamine was observed, whereas PGD2 was not generated under the same conditions. Mouse peritoneal CTMC as well as bone marrow-derived immature MC also responded to PLA2. Preincubation of CTMC with tyrosine kinase inhibitors, genistein, and herbimycin A, but not with pertussis toxin, resulted in abolition of the sensitivity to PLA2. The ability of type II PLA2 to induce histamine release was inhibited by an antibody or chemicals, both of which blocked the catalytic activity of type II PLA2. Heparin or an antibody recognizing the heparin-binding domain of type II PLA2 also suppressed the MC-degranulating activity, probably due to inhibition of binding of PLA2 to the cells. The interaction between heparan sulfate on cell surface and the heparin-binding domain of type II PLA2 may be important for the induction of exocytosis. The catalytic domain of the enzyme is also crucially important for the degranulation induction. Furthermore, we found that nerve growth factor, one of the potent regulators of MC function, significantly potentiated type II PLA2-induced histamine release from rat CTMC. These results suggest the possible role of extracellular type II PLA2 in activation of CTMC primed with nerve growth factor at inflamed sites. PMID:8228255

  3. Inhibitory effect of ganglioside on mastoparan-induced cytotoxicity and degranulation in lipid raft of connective tissue type mast cell.

    PubMed

    Nishikawa, Hirofumi; Kitani, Seiichi

    2011-01-01

    Antihistamine, the most important drug for Hymenoptera stinging, cannot attenuate cytotoxicity and mast cell direct activation by mastoparan that is the most abundant polypeptides in the venoms of social wasps. The aim of this study was to investigate whether gangliosides inhibit the effect of mastoparan on mast cells activation. The degranulation and cytotoxicity in canine cutaneous mastocytoma cells (CM-MC) were done by measurement of ?-hexosaminidase release and MTT assay. Lipid raft was isolated with discontinuous sucrose gradient centrifuge for the analysis of distribution of G?(q) and G?(i) protein by western blotting. We found that mastoparan induced the degranulation in (CM-MC) via direct activation of G?(i) and G?(q) with a decrease in their amount in lipid raft. Ganglioside G(D1a) (disialoganglioside) and G(M1) (monosialoganglioside) strongly reduced the degranulation and cytotoxicity through stabilizing the structure of lipid raft domain. In addition, mastoparan generated intracellular reactive oxygen species (ROS) independently from cytotoxicity, through arachidonic cascade but not G-protein activations. Crude wasp venom showed cytotoxicity and induction of the release from CM-MC, which were potently reduced by gangliosides. We show here that mastoparan activates both G?(i) and G?(q) protein and that the exogenous ganglioside G(D1a) and G(M1) inhibit the degranulation and cytotoxicity through stabilizing lipid raft. Gangliosides have potentials to be therapeutic tool or clinical prophylaxis for wasp stinging. PMID:21671308

  4. OM-X®, Fermented Vegetables Extract Suppresses Antigen-Stimulated Degranulation in Rat Basophilic Leukemia RBL-2H3 Cells and Passive Cutaneous Anaphylaxis Reaction in Mice.

    PubMed

    Itoh, Tomohiro; Miyake, Yasuyoshi; Kasashima, Takuya; Shimomiya, Yoshie; Nakamura, Yuki; Ando, Masashi; Tsukamasa, Yasuyuki; Takahata, Muneaki

    2015-09-01

    OM-X® is a hand-made and naturally manufactured probiotic supplement. This fermented food product is made from vegetables, fruits, seaweeds and mushrooms, using 12 strains of lactic acid bacteria and bifidobacteria. OM-X® is also known to have beneficial health properties, and some of its components show effects on antigen (Ag)-stimulated degranulation activity, indicating that OM-X® may be useful in the treatment of allergy responses and symptoms. In this study, we evaluated the inhibitory effects of OM-X® on Ag-stimulated degranulation in rat basophilic leukemia RBL-2H3 cells, clarified the underlying mechanisms, and determined the active compounds in OM-X® for suppression of degranulation. Treatment with OM-X® gradually suppressed Ag-stimulated degranulation throughout the maturation period. OM-X® also gradually produced melanoidins by lactic acid bacterial fermentation during the maturation process. There was a high correlation between the suppression levels of Ag-stimulated degranulation and the browning of OM-X®. Furthermore, the inhibition of Ag-stimulated degranulation by OM-X® was found to be partially due to the direct inactivation of NADPH oxidase. To elucidate the in vivo effects of OM- X®, type I allergy model mice were orally administered with OM-X®, and the passive cutaneous anaphylaxis (PCA) reaction was measured. OM-X® intake remarkably suppressed the PCA reaction. Taken together, our findings suggest that OMX® could be a beneficial food to ameliorate allergic reactions. PMID:26594768

  5. Fyn kinase controls Fc{epsilon}RI receptor-operated calcium entry necessary for full degranulation in mast cells

    SciTech Connect

    Sanchez-Miranda, Elizabeth; Ibarra-Sanchez, Alfredo; Gonzalez-Espinosa, Claudia

    2010-01-22

    IgE-antigen-dependent crosslinking of the high affinity IgE receptor (Fc{epsilon}RI) on mast cells leads to degranulation, leukotriene synthesis and cytokine production. Calcium (Ca{sup 2+}) mobilization is a sine qua non requisite for degranulation, allowing the rapid secretion of stored pro-inflammatory mediators responsible for allergy symptoms. Fyn is a Src-family kinase that positively controls Fc{epsilon}RI-induced mast cell degranulation. However, our understanding of the mechanism connecting Fyn activation to secretion of pre-synthesized mediators is very limited. We analyzed Fc{epsilon}RI-dependent Ca{sup 2+} mobilization in bone marrow-derived mast cells (BMMCs) differentiated from WT and Fyn -/- knock out mice. Fyn -/- BMMCs showed a marked defect in extracellular Ca{sup 2+} influx after Fc{epsilon}RI crosslinking but not after thapsigargin addition. High concentrations of Gadolinium (Gd{sup 3+}) partially blocked Fc{epsilon}RI-induced Ca{sup 2+} influx in WT cells but, in contrast, completely inhibited Ca{sup 2+} mobilization in Fyn -/- cells. Low concentrations of an inhibitor of the canonical transient receptor potential (TRPC) Ca{sup 2+} channels (2-aminoethoxyphenyl-borane, 2-APB) blocked Fc{epsilon}RI-induced maximal Ca{sup 2+} rise in WT but not in Fyn -/- cells. Ca{sup 2+} entry through Fyn-controlled, 2-APB sensitive channels was found to be important for full degranulation and IL-2 mRNA accumulation in WT cells. Immunoprecipitation assays showed that Fyn kinase interacts with TRPC 3/6/7 channels after IgE-antigen stimulation, but its association is not related to protein tyrosine phosphorylation. Results indicate Fyn kinase mediates the receptor-dependent activation of TRPC channels that contribute to degranulation in Fc{epsilon}RI-stimulated mast cells.

  6. Silver nanoparticle-induced degranulation observed with quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Yang, Wenzhong; Lee, Seungrag; Lee, Jiyong; Bae, Yoonsung; Kim, Dugyoung

    2010-07-01

    Monitoring a degranulation process in a live mast cell is a quite important issue in immunology and pharmacology. Because the size of a granule is normally much smaller than the resolution limit of an optical microscope system, there is no direct real-time live cell imaging technique for observing degranulation processes except for fluorescence imaging techniques. In this research, we propose optical quantitative phase microscopy (QPM) as a new observation tool to study degranulation processes in a live mast cell without any fluorescence labeling. We measure the cell volumes and the cross sectional profiles (x-z plane) of an RBL-2H3 cell and a HeLa cell, before and after they are exposed to calcium ionophore A23187 and silver nanoparticles (AgNPs). We verify that the volume and the cross sectional line profile of the RBL-2H3 cell were changed significantly when it was exposed to A23187. When 50 ?g/mL of AgNP is used instead of A23187, the measurements of cell volume and cross sectional profiles indicate that RBL-2H3 cells also follow degranulation processes. Degranulation processes for these cells are verified by monitoring the increase of intracellular calcium ([Ca2+]i) and histamine with fluorescent methods.

  7. Gastrin-releasing peptide induces itch-related responses through mast cell degranulation in mice.

    PubMed

    Andoh, Tsugunobu; Kuwazono, Takashi; Lee, Jung-Bum; Kuraishi, Yasushi

    2011-10-01

    Gastrin-releasing peptide (GRP), secreted from the central terminals of primary afferents, is involved in the transmission of itch signals in the spinal dorsal horn. Although primary afferents containing GRP are distributed throughout the skin, the role of peripherally released GRP in the itch response is unknown. We investigated whether GRP acts on the skin to induce an itch response in mice. Intradermal injections of GRP(18-27) (1-300 nmol/site) elicited scratching. GRP(18-27)-induced scratching was inhibited by the ?-opioid receptor antagonist naltrexone hydrochloride, the BB(2) bombesin receptor antagonist RC-3095, the H(1) histamine receptor antagonists fexofenadine hydrochloride and chlorpheniramine maleate, and the PAR(2) proteinase-activated receptor antagonist FSLLRY-NH(2). Mast cell deficiency significantly, but not completely, reduced the GRP(18-27)-induced scratching. BB(2) bombesin receptors are present in mast cells in the skin, and intradermal injection of GRP(18-27), not only induced scratching, but also led to mast cell degranulation. GRP(18-27)-induced mast cell degranulation was inhibited by the BB(2) bombesin receptor antagonist RC-3095. These results suggest that peripherally released GRP can induce an itch response, at least partly, through activation of BB(2) receptors present in the mast cells, triggering their degradation and the release of histamine and the serine proteinase, tryptase. PMID:21933692

  8. Quantifying psoralen in tissues by fluorescence: dosimetry for psoralen administration followed by ultraviolet A irradiation (PUVA) to block restenosis

    NASA Astrophysics Data System (ADS)

    Jacques, Steven L.; Buckley, Lisa A.; Prahl, Scott A.; Gregory, Kenton W.

    1994-07-01

    PUVA therapy may prove effective in preventing restenosis of vessels following balloon angioplasty to open vessels narrowed by atherosclerosis. The technique relies on the ability of PUVA (psoralen administration followed by ultraviolet A irradiation) to cause crosslinks and monoadducts that prevent cellular proliferation without causing cell death. Such PUVA treatment has been successful in controlling cutaneous cell proliferation of psoriasis. The efficacy of PUVA treatment depends on the drug concentration and the light dose. The amount of light delivered is easily modified to adapt to variations in the drug concentration if the drug levels in the vessel wall are known. This paper demonstrates the feasibility of assaying psoralen levels in tissues and in serum samples using psoralen fluorescence as an indictor.

  9. Bullous pemphigoid. Occurrence in a patient with mycosis fungoides receiving PUVA and topical nitrogen mustard therapy

    SciTech Connect

    Patterson, J.W.; Ali, M.; Murray, J.C.; Hazra, T.A.

    1985-04-01

    A 57-year-old woman with mycosis fungoides developed blisters within cutaneous plaques while receiving PUVA therapy and topical nitrogen mustard. Direct and indirect immunofluorescence studies showed the findings of bullous pemphigoid. Her bullous disease was controlled after cessation of these therapies and institution of prednisone and methotrexate. During the 5 months following completion of a course of electron-beam therapy, she has been free of the cutaneous manifestations of both diseases. Previous instances of PUVA-related pemphigoid have occurred in psoriatics. The role of ultraviolet light in the induction of pemphigoid is discussed, particularly with regard to its possible interaction with the altered skin of psoriasis or mycosis fungoides. Some of the rare cases of bullous mycosis fungoides might actually have represented ultraviolet-unmasked bullous pemphigoid.

  10. DNA damage in human skin fibroblasts exposed to UVA light used in clinical PUVA treatment

    SciTech Connect

    Bredberg, A.

    1981-06-01

    Human skin fibroblasts were irradiated with a clinically used UVA light source. The doses (1.1 and 3 J/cm2) were similar to those reaching the dermis during clinical PUVA treatment of psoriasis. DNA strand breaks, as determined by alkaline elution, were formed in a dose-dependent way and disappeared within 1 hr of postincubation at 37 degrees C. These findings have clinical implications since UVA-induced DNA damage may be accompanied by mutagenic and tumor promoting effects.

  11. The inhibitory effect of piperine from Fructus piperis extract on the degranulation of RBL-2H3 cells.

    PubMed

    Huang, Jing; Zhang, Tao; Han, Shengli; Cao, Jingjing; Chen, Qinhua; Wang, Sicen

    2014-12-01

    Allergy is an abnormal immune response to an allergen. Type I hypersensitivity is an immunoglobulin (Ig) E-mediated allergic disorder. Fructus piperis is derived from the ripe fruit of the pepper, which is widely used as a spice in human diets and is also administered as a medicine in many countries. Piperine has been shown to have anti-oxidant, anti-depressant, anti-tumor, and anti-inflammatory activities. However, the effect of piperine on IgE-mediated allergic responses has not been reported. Here, the rat basophilic leukemia cells by membrane chromatography (RBL-2H3/CMC) coupled to high performance liquid chromatography/mass spectrometry (HPLC/MS) to discover and identify piperine can bind to RBL-2H3 cell membranes. Piperine inhibited the expression of cytokines, and the release of both ?-hexosaminidase and histamine, which could be stimulated by antigen in RBL-2H3 mast cells. We found that the levels of intracellular Ca(2+) also decreased. Furthermore, RT-PCR showed that the mRNA expression levels of IL-4, IL-13, and TNF-? were significantly suppressed by piperine. The inhibitory effect of piperine on IgE-mediated degranulation and cytokine production by RBL-2H3 cells may be caused by the inhibition of IgE-mediated signaling pathways, including the phosphorylation of Lyn, p38, Erk, and Ras. In summary, piperine can inhibit antigen-induced allergic reactions that control degranulation. PMID:25307563

  12. Quantitative analysis on PUVA-induced skin photodamages using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Zhai, Juan; Guo, Zhouyi; Liu, Zhiming; Xiong, Honglian; Zeng, Changchun; Jin, Ying

    2009-08-01

    Psoralen plus ultraviolet A radiation (PUVA) therapy is a very important clinical treatment of skin diseases such as vitiligo and psoriasis, but associated with an increased risk of skin photodamages especially photoaging. Since skin biopsy alters the original skin morphology and always requires an iatrogenic trauma, optical coherence tomography (OCT) appears to be a promising technique to study skin damage in vivo. In this study, the Balb/c mice had 8-methoxypsralen (8-MOP) treatment prior to UVA radiation was used as PUVA-induced photo-damaged modal. The OCT imaging of photo-damaged group (modal) and normal group (control) in vivo was obtained of mice dorsal skin at 0, 24, 48, 72 hours after irradiation respectively. And then the results were quantitatively analyzed combined with histological information. The experimental results showed that, PUVA-induced photo-damaged skin had an increase in epidermal thickness (ET), a reduction of attenuation coefficient in OCT images signal, and an increase in brightness of the epidermis layer compared with the control group. In conclusion, noninvasive high-resolution imaging techniques such as OCT may be a promising tool for photobiological studies aimed at assessing photo-damage and repair processes in vivo. It can be used to quantitative analysis of changes in photo-damaged skin, such as the ET and collagen in dermis, provides a theoretical basis for treatment and prevention of skin photodamages.

  13. Emodin attenuates A23187-induced mast cell degranulation and tumor necrosis factor-? secretion through protein kinase C and I?B kinase 2 signaling.

    PubMed

    Kim, Dong-Young; Kang, Tae-Bong; Shim, Do-Wan; Sun, Xiao; Han, Ji-Won; Ji, Young-Eun; Kim, Tack-Joong; Koppula, Sushruta; Lee, Kwang-Ho

    2014-01-15

    Mast cells are known to play a pivotal role in allergic diseases. Cross-linking of the high-affinity IgE receptor (Fc?RI) is known to be one of the major causes that lead to degranulation and allergic inflammation. An increase in intracellular calcium (Ca(2+)) concentration also triggers degranulation, bypassing receptor activation. Emodin (1,3,8-trihydroxy-6-methylanthraquinone) is known to exhibit a variety of pharmacological activities including anti-allergic effects. However, the detailed molecular mechanisms involved in exhibiting anti-allergic effects by emodin were remained to be clarified. In the present investigation we report the regulatory function of emodin on the allergic signal mediators through Ca(2+) ionophore activation in mast cells. Emodin significantly inhibited A23187-induced tumor necrosis factor-? production and degranulation through the attenuation of protein kinase C, I?B kinase 2, and soluble N-ethylmaleimide-sensitive fusion factor attachment protein receptor complex formation, bypassing Fc?RI activation. Data from our study indicated that emodin acts by regulating multiple signaling pathways in inhibiting the allergic reactions in mast cells. PMID:24239713

  14. Sulfur mustard primes human neutrophils for increased degranulation and stimulates cytokine release via TRPM2/p38 MAPK signaling

    SciTech Connect

    Ham, Hwa-Yong; Hong, Chang-Won; Lee, Si-Nae; Kwon, Min-Soo; Kim, Yeon-Ja; Song, Dong-Keun

    2012-01-01

    Sulfur mustard (2,2?-bis-chloroethyl-sulfide; SM) has been a military threat since the World War I. The emerging threat of bioterrorism makes SM a major threat not only to military but also to civilian world. SM injury elicits an inflammatory response characterized by infiltration of neutrophils. Although SM was reported to prime neutrophils, the mechanism has not been identified yet. In the present study, we investigated the mechanism of SM-induced priming in human neutrophils. SM increased [Ca{sup 2+}]{sub i} in human neutrophils in a concentration-dependent fashion. Transient receptor potential melastatin (TRPM) 2 inhibitors (clotrimazole, econazole and flufenamic acid) and silencing of TRPM2 by shRNA attenuated SM-induced [Ca{sup 2+}]{sub i} increase. SM primed degranulation of azurophil and specific granules in response to activation by fMLP as previously reported. SB203580, an inhibitor of p38 MAPK, inhibited SM-induced priming. Neither PD98057, an ERK inhibitor, nor SP600215, a JNK inhibitor, inhibited SM-induced priming. In addition, SM enhanced phosphorylation of NF-kB p65 and release of TNF-?, interleukin (IL)-6 and IL-8. SB203580 inhibited SM-induced NF-kB phosphorylation and cytokine release. These results suggest the involvement of TRPM2/p38 MAPK pathway in SM-induced priming and cytokines release in neutrophils. -- Highlights: ? SM increased [Ca{sup 2+}]{sub i} in human neutrophils through TPRM2-mediated calcium influx. ? SM primed degranulation of azurophil and specific granules. ? SM enhanced p38 MAPK and NF-?B p65 phosphorylation in human neutrophils. ? SM enhanced release of TNF-?, interleukin (IL)-6 and IL-8 from human neutrophils. ? SB203580 inhibited SM-induced priming, NF-?B p65 phosphorylation and cytokine release.

  15. ORAI1-mediated calcium influx is required for human cytotoxic lymphocyte degranulation and target cell lysis

    PubMed Central

    Maul-Pavicic, Andrea; Chiang, Samuel C. C.; Rensing-Ehl, Anne; Jessen, Birthe; Fauriat, Cyril; Wood, Stephanie M.; Sjöqvist, Sebastian; Hufnagel, Markus; Schulze, Ilka; Bass, Thilo; Schamel, Wolfgang W.; Fuchs, Sebastian; Pircher, Hanspeter; McCarl, Christie-Ann; Mikoshiba, Katsuhiko; Schwarz, Klaus; Feske, Stefan; Bryceson, Yenan T.; Ehl, Stephan

    2011-01-01

    Lymphocytes mediate cytotoxicity by polarized release of the contents of cytotoxic granules toward their target cells. Here, we have studied the role of the calcium release-activated calcium channel ORAI1 in human lymphocyte cytotoxicity. Natural killer (NK) cells obtained from an ORAI1-deficient patient displayed defective store-operated Ca2+ entry (SOCE) and severely defective cytotoxic granule exocytosis leading to impaired target cell lysis. Similar findings were obtained using NK cells from a stromal interaction molecule 1-deficient patient. The defect occurred at a late stage of the signaling process, because activation of leukocyte functional antigen (LFA)-1 and cytotoxic granule polarization were not impaired. Moreover, pharmacological inhibition of SOCE interfered with degranulation and target cell lysis by freshly isolated NK cells and CD8+ effector T cells from healthy donors. In addition to effects on lymphocyte cytotoxicity, synthesis of the chemokine macrophage inflammatory protein-1? and the cytokines TNF-? and IFN-? on target cell recognition was impaired in ORAI1-deficient NK cells, as previously described for T cells. By contrast, NK cell cytokine production induced by combinations of IL-12, IL-15, and IL-18 was not impaired by ORAI1 deficiency. Taken together, these results identify a critical role for ORAI1-mediated Ca2+ influx in granule exocytosis for lymphocyte cytotoxicity as well as for cytokine production induced by target cell recognition. PMID:21300876

  16. Modulation of human neutrophil oxidative metabolism and degranulation by extract of Tamarindus indica L. fruit pulp.

    PubMed

    Paula, Fabiana S; Kabeya, Luciana M; Kanashiro, Alexandre; de Figueiredo, Andréa S G; Azzolini, Ana Elisa C S; Uyemura, Sérgio A; Lucisano-Valim, Yara Maria

    2009-01-01

    The tamarind (Tamarindus indica L.) is indigenous to Asian countries and widely cultivated in the American continents. The tamarind fruit pulp extract (ExT), traditionally used in spices, food components and juices, is rich in polyphenols that have demonstrated anti-atherosclerotic, antioxidant and immunomodulatory activities. This study evaluated the modulator effect of a crude hydroalcoholic ExT on some peripheral human neutrophil functions. The neutrophil reactive oxygen species generation, triggered by opsonized zymosan (OZ), n-formyl-methionyl-leucyl-phenylalanine (fMLP) or phorbol myristate acetate (PMA), and assessed by luminol- and lucigenin-enhanced chemiluminescence (LumCL and LucCL, respectively), was inhibited by ExT in a concentration-dependent manner. ExT was a more effective inhibitor of the PMA-stimulated neutrophil function [IC50 (in microg/10(6)cells)=115.7+/-9.7 (LumCL) and 174.5+/-25.9 (LucCL)], than the OZ- [IC50=248.5+/-23.1 (LumCL) and 324.1+/-34.6 (LucCL)] or fMLP-stimulated cells [IC50=178.5+/-12.2 (LumCL)]. The ExT also inhibited neutrophil NADPH oxidase activity (evaluated by O2 consumption), degranulation and elastase activity (evaluated by spectrophotometric methods) at concentrations higher than 200 microg/10(6)cells, without being toxic to the cells, under the conditions assessed. Together, these results indicate the potential of ExT as a source of compounds that can modulate the neutrophil-mediated inflammatory diseases. PMID:19022329

  17. Neuropeptides degranulate serous cells of ferret tracheal glands

    SciTech Connect

    Gashi, A.A.; Borson, D.B.; Finkbeiner, W.E.; Nadel, J.A.; Basbaum, C.B.

    1986-08-01

    To determine whether serous or mucous cells in tracheal submucosal glands respond to the neuropeptides substance P (SP) and vasoactive intestinal peptide (VIP). The authors studied the peptide-induced changes in gland cell morphology accompanying release of TVSO4-labeled macromolecules from tracheal explants of ferrets. Explants were labeled for 1 h in medium containing TVSO4 and washed for 3.5 additional hours. Base-line secretion in the absence of drugs declined between 1.5 and 3.5 h after the pulse. Between 2.5 and 3.5 h, the average percent change in counts per minute recovered per sample period was not significantly different from zero. Substance P and VIP added 4 h after labeling each increased greatly the release of TVSO4-labeled macromolecules above base line. Bethanechol, a muscarinic-cholinergic agonist, increased secretion by an average of 142% above base line. Light and electron microscopy of the control tissues showed glands with narrow lumens and numerous secretory granules. Glands treated with SP or VIP had enlarged lumens and the serous cells were markedly degranulated. These phenomena were documented by morphometry and suggest that SP and VIP cause secretion from glands at least partially by stimulating exocytosis from serous cells.

  18. Singlet oxygen generation in PUVA therapy studied using electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Serrano-Pérez, Juan José; Olaso-González, Gloria; Merchán, Manuela; Serrano-Andrés, Luis

    2009-06-01

    The ability of furocoumarins to participate in the PUVA (Psoralen + UV-A) therapy against skin disorders and some types of cancer, is analyzed on quantum chemical grounds. The efficiency of the process relies on its capability to populate its lowest triplet excited state, and then either form adducts with thymine which interfere DNA replication or transfer its energy, generating singlet molecular oxygen damaging the cell membrane in photoactivated tissues. By determining the spin-orbit couplings, shown to be the key property, in the intersystem crossing yielding the triplet state of the furocoumarin, the electronic couplings in the triplet-triplet energy transfer process producing the singlet oxygen, and the reaction rates and lifetimes, the efficiency in the phototherapeutic action of the furocoumarin family is predicted as: khellin < 5-methoxypsoralen (5-MOP) < 8-methoxypsoralen (8-MOP) < psoralen < 4,5?,8-trimethylpsoralen (TMP) < 3-carbethoxypsoralen (3-CPS), the latter being the most efficient photosensitizer and singlet oxygen generator.

  19. Suppressive effects of carotenoids on the antigen-induced degranulation in RBL-2H3 rat basophilic leukemia cells.

    PubMed

    Manabe, Yuki; Hirata, Takashi; Sugawara, Tatsuya

    2014-01-01

    In this study, the anti-degranulation effects of fifteen carotenoids were evaluated using RBL-2H3 rat basophilic leukemia cell line as a mast cell model. Nine carotenoids, fucoxanthin, zeaxanthin, ?-carotene, astaxanthin, 3-hydroxyechinenone, fucoxanthinol, lycopene, ?-cryptoxanthin, and siphonaxanthin significantly suppressed antigen-induced mast cell degranulation. Under the same conditions, the cellular carotenoid contents were quantified using high performance liquid chromatography-photodiode array (HPLC-PDA). There was no correlation between the cellular carotenoid contents and their anti-degranulation activities. These results indicate that the differences in the anti-degranulation activities of carotenoids were not related to their uptake by the cells. PMID:24492380

  20. Mast cell degranulation induced by type 1 fimbriated Escherichia coli in mice.

    PubMed Central

    Malaviya, R; Ross, E; Jakschik, B A; Abraham, S N

    1994-01-01

    The strategic location of mast cells at the host-environment interface and their ability to release potent mediators of inflammation have suggested that these cells may play a pivotal role in host defense against bacterial infection. The ability of the opportunistic pathogen, Escherichia coli, to induce degranulation of mast cells obtained from the mouse peritoneum was investigated. We determined that unlike a mutant derivative deficient in the FimH subunit of the fimbriae or nonfimbriated E. coli, type 1 fimbriated E. coli induced mast cell degranulation in vitro. The magnitude of mast cell degranulation was directly proportional to the number of adherent bacteria on the cell surface in the initial period of the interaction. Using a mouse model of bacterial peritonitis, we demonstrated mast cell degranulation and histamine release by type 1 fimbriated bacteria in vivo. Furthermore, beads coated with FimH but not with FimA, the major subunit of type 1 fimbriae, evoked mast cell release of histamine in vivo in amounts comparable to that elicited by type 1 fimbriated E. coli. These studies reveal that mast cells can be degranulated by interaction with type 1 fimbriated E. coli and that FimH, the mannose-binding component of the fimbriae, is a potent mast cell stimulant. Images PMID:7512987

  1. Flow microfluorometric analysis of phagocyte degranulation in bacteria-infected whole human blood cell cultures

    NASA Astrophysics Data System (ADS)

    Kravtsov, Alexander L.; Bobyleva, Elena V.; Grebenyukova, Tatyana P.; Kuznetsov, Oleg S.; Kulyash, Youri V.

    2002-07-01

    A quantitative flow microfluorometric method was used to study the intensity of human blood phagocyte degranulation in response to viable staphylococcus aureus or Yersinia pestis cells. Microorganisms were added directly to defibrinated whole blood. Uninfected and infected blood samples were incubated at 37 degrees C to 8 h. The results were recorded in dynamics after the staining of whole blood with acridine orange solution. Lymphocytes with a low azurophilic granule per cell content were discriminated from phagocytes by the measurement of single cell red cytoplasmic granule fluorescence. 30,000 cells in each sample were examined. S. aureus cells caused a dose-dependent decrease in the number of phagocytes having a high red cytoplasmic fluorescence intensity and a corresponding increase in the weakly fluorescence cell population. In the presence of an initial S. aureus-to-phagocyte ratio more than 1:1, degranulation was measured after 3 h of incubation and to 8 h the percentage of degranulated phagocytes was at least 100 percent Y. pestis cells grown for 48 h at 28 degrees C caused at same condition as the degranulation only about 50 percent of cells. Y.pestis EV cells preincubated in broth for 12 h at 37 degrees C did no stimulate the phahocyte degranulation. The results of these studies suggest that analysis of cell populations via flow microfluorimeter technology may be a powerful tool in analysis bacterial infection.

  2. Soluble IL-2 receptor and CD25 cells in psoriasis: effects of cyclosporin A and PUVA therapy.

    PubMed Central

    Duncan, J I; Horrocks, C; Ormerod, A D; Powles, A V; Whiting, P H; Fry, L; Thomson, A W

    1991-01-01

    A study was conducted to quantify soluble IL-2 receptor (sIL-2R) levels in sera of 57 chronic plaque psoriasis patients and correlate these measurements with disease activity and the number of IL-2R-positive (CD25+) lymphocytes in lesional biopsies of 11 cyclosporin A (CsA) and 13 psoralen plus ultraviolet radiation (PUVA) treated patients. Levels of sIL-2R showed a strong correlation with the psoriasis area and severity index (PASI). CsA and PUVA significantly reduced the PASI and sIL-2R levels to a similar degree after 4 weeks of treatment. Although the majority of CsA-treated patients who were biopsied showed reductions in lesional CD25+ cells, these did not reach statistical significance; in five patients biopsied who had PUVA treatment, no consistent effect on the numbers of CD25+ cells was observed. A significant correlation was found between CD25+ cells in lesional biopsies and the PASI score. PMID:1864010

  3. A Combination of Screening and Computational Approaches for the Identification of Novel Compounds That Decrease Mast Cell Degranulation

    PubMed Central

    McShane, Marisa P.; Friedrichson, Tim; Giner, Angelika; Meyenhofer, Felix; Barsacchi, Rico; Bickle, Marc

    2015-01-01

    High-content screening of compound libraries poses various challenges in the early steps in drug discovery such as gaining insights into the mode of action of the selected compounds. Here, we addressed these challenges by integrating two biological screens through bioinformatics and computational analysis. We screened a small-molecule library enriched in amphiphilic compounds in a degranulation assay in rat basophilic leukemia 2H3 (RBL-2H3) cells. The same library was rescreened in a high-content image-based endocytosis assay in HeLa cells. This assay was previously applied to a genome-wide RNAi screen that produced quantitative multiparametric phenotypic profiles for genes that directly or indirectly affect endocytosis. By correlating the endocytic profiles of the compounds with the genome-wide siRNA profiles, we identified candidate pathways that may be inhibited by the compounds. Among these, we focused on the Akt pathway and validated its inhibition in HeLa and RBL-2H3 cells. We further showed that the compounds inhibited the translocation of the Akt-PH domain to the plasma membrane. The approach performed here can be used to integrate chemical and functional genomics screens for investigating the mechanism of action of compounds. PMID:25838434

  4. Propofol Attenuates Small Intestinal Ischemia Reperfusion Injury through Inhibiting NADPH Oxidase Mediated Mast Cell Activation

    PubMed Central

    Gan, Xiaoliang; Xing, Dandan; Su, Guangjie; Li, Shun; Luo, Chenfang; Irwin, Michael G.; Xia, Zhengyuan; Li, Haobo; Hei, Ziqing

    2015-01-01

    Both oxidative stress and mast cell (MC) degranulation participate in the process of small intestinal ischemia reperfusion (IIR) injury, and oxidative stress induces MC degranulation. Propofol, an anesthetic with antioxidant property, can attenuate IIR injury. We postulated that propofol can protect against IIR injury by inhibiting oxidative stress subsequent from NADPH oxidase mediated MC activation. Cultured RBL-2H3 cells were pretreated with antioxidant N-acetylcysteine (NAC) or propofol and subjected to hydrogen peroxide (H2O2) stimulation without or with MC degranulator compound 48/80 (CP). H2O2 significantly increased cells degranulation, which was abolished by NAC or propofol. MC degranulation by CP further aggravated H2O2 induced cell degranulation of small intestinal epithelial cell, IEC-6 cells, stimulated by tryptase. Rats subjected to IIR showed significant increases in cellular injury and elevations of NADPH oxidase subunits p47phox and gp91phox protein expression, increases of the specific lipid peroxidation product 15-F2t-Isoprostane and interleukin-6, and reductions in superoxide dismutase activity with concomitant enhancements in tryptase and ?-hexosaminidase. MC degranulation by CP further aggravated IIR injury. And all these changes were attenuated by NAC or propofol pretreatment, which also abrogated CP-mediated exacerbation of IIR injury. It is concluded that pretreatment of propofol confers protection against IIR injury by suppressing NADPH oxidase mediated MC activation. PMID:26246867

  5. Regulation of human eosinophil degranulation and activation by endogenous phospholipase A2.

    PubMed Central

    White, S R; Strek, M E; Kulp, G V; Spaethe, S M; Burch, R A; Neeley, S P; Leff, A R

    1993-01-01

    The unique granular proteins of eosinophils may have a pathogenetic role in asthma and in the defense against parasitic infestations. However, the mechanisms regulating eosinophil degranulation are largely unknown. We examined the hypothesis that release of these proteins is regulated by endogenous activation of phospholipase A2. Human eosinophils (HE) were isolated from the peripheral blood of 42 subjects either by Percoll density separation or by negative-selection immunomagnetic fractionation. Eosinophil activation was initiated in vitro with 10(-6) M FMLP and 5 micrograms/ml cytochalasin B and was assessed by measurement of eosinophil peroxidase (EPO), leukotriene C4 (LTC4) and superoxide radical (.O2-) secretion. Treatment of HE with 100 microM mepacrine before activation blocked EPO release (2.0 +/- 0.2 vs 10.2 +/- 2.1% cell content for activated HE, P < 0.004, n = 9), .O2- generation (2.6 +/- 0.9 vs 44.2 +/- 10.8 nmol/ml per 10(6) HE, P < 0.002, n = 5), and LTC4 secretion (68.2 +/- 32.2 vs 1,125.2 +/- 526.8 pg/ml per 10(6) HE, P < 0.04, n = 8). Pretreatment of HE with 100 microM 4-bromophenacyl bromide before activation similarly blocked EPO release, .O2- generation and LTC4 secretion. Addition of AA to HE after treatment with 100 microM mepacrine and before subsequent activation reversed the inhibition of both EPO (10.4 +/- 2.2% with 1 microM AA vs 2.0 +/- 0.2% for mepacrine, n = 5, P < 0.02) and LTC4 secretion (695.1 +/- 412.9 with 10 microM AA vs 68.2 +/- 32.2 pg/ml per 10(6) HE for mepacrine, n = 8, P < 0.04), but did not reverse inhibition of .O2- generation by mepacrine. We demonstrate that secretion of preformed cytotoxic proteins and .O2- by eosinophils is regulated endogenously by phospholipase A2. PMID:8387540

  6. Central role of mitochondria and p53 in PUVA-induced apoptosis in human keratinocytes cell line NCTC-2544

    SciTech Connect

    Viola, Giampietro Fortunato, Elena; Cecconet, Laura; Del Giudice, Laura; Dall'Acqua, Francesco; Basso, Giuseppe

    2008-02-15

    Despite strong evidence concerning the high efficiency of PUVA therapy (psoralen plus UVA light), its mechanism of action has not yet been fully elucidated. In this study, we have evaluated in a cell line of human keratinocytes (NCTC-2544) the effects of two linear psoralen derivatives, 8-methoxypsoralen (8-MOP) and 5-methoxypsoralen (5-MOP), that are widely used in PUVA therapy and two angular derivatives, Angelicin (ANG) and 4,6,4'-trymetyl angelicin (TMA). All derivatives photoinduce cellular death, TMA being the most active compound. The cell cycle analysis showed that the four derivatives induce, 24 h after irradiation, a cell cycle arrest in G1 phase later followed by massive apoptosis. The G1 arrest is correlated to an increase in the expression of p21{sup Waf1/Cip1}, a protein associated with the cell cycle block and apoptosis. Furthermore, treatment of NCTC-2544 resulted in p53 activation by 5-MOP, 8-MOP, and ANG but not TMA and its phosphorylation at serine-15. The levels of p21{sup Waf1/Cip1} paralleled p53 protein staining pattern suggesting that p53 activation correlated with p21{sup Waf1/Cip1} induction. Simultaneous to p53 activation, psoralens induced mitochondrial depolarization, cytochrome c release, mitochondrial production of reactive oxygen species, as well as caspase-3 and -9 activation. Thus these results strongly indicate the necessity of p53 activation and the induction of the apoptotic machinery downstream of mitochondria.

  7. Mast cell degranulation mediates compound 48/80-induced hyperalgesia in mice

    PubMed Central

    Chatterjea, Devavani; Wetzel, Abigail; Mack, Madison; Engblom, Camilla; Allen, Juliann; Mora-Solano, Carolina; Paredes, Luisa; Balsells, Evelyn; Martinov, Tijana

    2012-01-01

    Mast cells mediate allergies, hypersensitivities, host defense, and venom neutralization. An area of recent interest is the contribution of mast cells to inflammatory pain. Here we found that specific, local activation of mast cells produced plantar hyperalgesia in mice. Basic secretagogue compound 48/80 induced plantar mast cell degranulation accompanied by thermal hyperalgesia, tissue edema, and neutrophil influx in the hindpaws of ND4 Swiss mice. Blocking mast cell degranulation, neutrophil extravasation, and histamine signaling abrogated these responses. Compound 48/80 also produced edema, pain, and neutrophil influx in WT C57BL/6 but not in genetically mast cell-deficient C57BL/6-KitW-sh/W-sh mice. These responses were restored following plantar reconstitution with bone marrow-derived cultured mast cells. PMID:22828511

  8. Regulation of Neutrophil Degranulation and Cytokine Secretion: A Novel Model Approach Based on Linear Fitting

    PubMed Central

    Naegelen, Isabelle; Beaume, Nicolas; Plançon, Sébastien; Schenten, Véronique; Tschirhart, Eric J.; Bréchard, Sabrina

    2015-01-01

    Neutrophils participate in the maintenance of host integrity by releasing various cytotoxic proteins during degranulation. Due to recent advances, a major role has been attributed to neutrophil-derived cytokine secretion in the initiation, exacerbation, and resolution of inflammatory responses. Because the release of neutrophil-derived products orchestrates the action of other immune cells at the infection site and, thus, can contribute to the development of chronic inflammatory diseases, we aimed to investigate in more detail the spatiotemporal regulation of neutrophil-mediated release mechanisms of proinflammatory mediators. Purified human neutrophils were stimulated for different time points with lipopolysaccharide. Cells and supernatants were analyzed by flow cytometry techniques and used to establish secretion profiles of granules and cytokines. To analyze the link between cytokine release and degranulation time series, we propose an original strategy based on linear fitting, which may be used as a guideline, to (i) define the relationship of granule proteins and cytokines secreted to the inflammatory site and (ii) investigate the spatial regulation of neutrophil cytokine release. The model approach presented here aims to predict the correlation between neutrophil-derived cytokine secretion and degranulation and may easily be extrapolated to investigate the relationship between other types of time series of functional processes. PMID:26579547

  9. Impaired mast cell maturation and degranulation and attenuated allergic responses in Ndrg1-deficient mice.

    PubMed

    Taketomi, Yoshitaka; Sunaga, Kohei; Tanaka, Satoshi; Nakamura, Masanori; Arata, Satoru; Okuda, Tomohiko; Moon, Tae-Chul; Chang, Hyeun-Wook; Sugimoto, Yukihiko; Kokame, Koichi; Miyata, Toshiyuki; Murakami, Makoto; Kudo, Ichiro

    2007-06-01

    We have previously reported that N-myc downstream regulated gene-1 (NDRG1) is an early inducible protein during the maturation of mouse bone marrow-derived mast cells (BMMCs) toward a connective tissue mast cell-like phenotype. To clarify the function of NDRG1 in mast cells and allergic responses, we herein analyzed mast cell-associated phenotypes of mice lacking the Ndrg1 gene. Allergic responses including IgE-mediated passive systemic and cutaneous anaphylactic reactions were markedly attenuated in Ndrg1-deficient mice as compared with those in wild-type mice. In Ndrg1-deficient mice, dermal and peritoneal mast cells were decreased in number and morphologically abnormal with impaired degranulating ability. Ex vivo, Ndrg1-deficient BMMCs cocultured with Swiss 3T3 fibroblasts in the presence of stem cell factor, a condition that facilitates the maturation of BMMCs toward a CTMC-like phenotype, displayed less exocytosis than replicate wild-type cells after the cross-linking of FcepsilonRI or stimulation with compound 48/80, even though the exocytotic response of IL-3-maintained, immature BMMCs from both genotypes was comparable. Unlike degranulation, the production of leukotriene and cytokines by cocultured BMMCs was unaffected by NDRG1 deficiency. Taken together, the altered phenotypes of Ndrg1-deficient mast cells both in vivo and ex vivo suggest that NDRG1 has roles in the terminal maturation and effector function (degranulation) of mast cells. PMID:17513753

  10. Dexmedetomidine alleviates the spinal cord ischemia-reperfusion injury through blocking mast cell degranulation

    PubMed Central

    Ma, Jun; Zhang, Xiao-Long; Wang, Cheng-Yu; Lin, Zhi; Tao, Jie-Ru; Liu, Hua-Cheng

    2015-01-01

    Objective: To investigate the neuro-protective effects of dexmedetomidine (dex) on I/R-induced spinal injury and potential mechanisms. Methods: sprague-Dawley rats in the treatment group received intraperitoneal injections of 25 mg/kg dexmedetomidine, MC stabilizer cromolyn (100 mg/kg), MCs stimuliser compound 48/80 (80 mg/kg), PBS at 24 h befor IR. Underwent 5 minutes of aortic occlusion via median sternotomy, functional scores were recorded at 12, 24, 36 and 48 hours after reperfusion. Additionally, 3 mice underwent sham surgery with sternotomy and dissection of the aorta and subclavian artery with no occlusion. Spinal cords were examined for protein kinase B (AKT), CREB, and brain-derived neurotrophic factor (BDNF) following treatment alone or ischemia-reperfusion surgery. Collected the serum to observe the expression of pro-inflammation cytokines (TNF-?, INF-? and IL-1?) and anti-inflammation cytokines (TGF-?, IL-10 and IL-6). Then the MCs were harvested to test the expression surface molecular of Fc?R and MCs’ degranulation. Results: Pretreated the rats with dexmedetomidine has higher neurologic function at all time points after I/R injury. We collected the serum of rats then detected the pro-inflammation cytokines TNF-?, INF-? and IL-1? levels and anti-inflammation cytokinses TGF-?, IL-10 and IL-6 levels, found that the pro-inflammation cytokines of dexmedetomidine group was decreased whereas the anti-inflammation cytokinses was increased. At the same time the protect protein of AKT, CREB and mRNA BDNF were increased. They had the same results with cromolyn group, and opposite with the compound 48/80 group. We pretreated MCs with dexmedetomidine in vitro, and found that the activity surface molecular of MCs was down-regulation, and MCs degranulation was decreased. Conclusion: We thus demonstrate a possible mechanism by which dexmedetomidine alleviates spinal cord I/R injury through blocking the MCs degranulation. PMID:26628956

  11. Disaggregation of HeLa-Cx43- and HeLa-spheroids induced by PUVA and photo-oxidized psoralen (POP)

    NASA Astrophysics Data System (ADS)

    Lysenko, Eugene P.; Pliquett, Fritz; Wunderlich, Siegfried; Potapenko, Alexander Y.

    2003-10-01

    To investigate the effects of PUVA (psoralen + UVA-irradiation) and photooxidized psoralen (POP) on cell-cell junctions, two kinds of multicellular spheroids, which were grown from HeLa cells of epithelioid human cervix carcinoma, were used as a model systems: i) defective in intercellular communication through gap junctions (HeLa-spheroids) and ii) transfected with coding sequences of murine connexin Cx43 with restored gap-junction coupling (HeLa-Cx43-spheroids). It was been found that both PUVA and POP induced disaggregation of HeLa-spheroids as well as HeLa-Cx43-spheroids. It implies that gap-junction plaques are not, apparently, critical targets in psoralen-photosensitized disaggregation. The rate of disaggregation was estimated as inverse time of disaggregation of 50% or 100% spheroids in suspensions (1/t50 or 1/t100, respectively). The rate of PUVA-induced disaggregation was found to increase with the increase of UVA-fluence up to 85 kJ/m2. Photosensitization coefficient was highest at low UVA-fluences (4-6 kJ/m2) and significantly decreased with increase in UVA-fluence. The viability of cells in spheroids was estimated with the use of trypan blue stain. At low UVA-fluences, the process of disaggregation was found to occur without the formation of trypan positive cells in spheroids. Results obtained evidence that PUVA-induced disaggregation of spheroids may occur, at least partially, through the action of POP-products.

  12. The use of fractal dimension and lacunarity in the characterization of mast cell degranulation in rainbow trout (Onchorhynchus mykiss).

    PubMed

    Manera, M; Dezfuli, B S; Borreca, C; Giari, L

    2014-11-01

    Fractal analysis is a reliable method for describing, summarizing object complexity and heterogeneity and has been widely used in biology and medicine to deal with scale, size and shape management problems. The aim of present survey was to use fractal analysis as a complexity measure to characterize mast cells (MCs) degranulation in a rainbow trout ex vivo model (isolated organ bath). Compound 48/80, a condensation product of N-methyl-p-methoxyphenethylamine with formaldehyde, was adopted as MCs degranulation agent in trout intestinal strips. Fractal dimension (D), as a measure of complexity, 'roughness' and lacunarity (?), as a measure of rotational and translational invariance, heterogeneity, in other words, of the texture, were compared in MCs images taken from intestinal strips before and after compound 48/80 addition to evaluate if and how they were affected by degranulation. Such measures were also adopted to evaluate their discrimination efficacy between compound 48/80 degranulated group and not degranulated group and the results were compared with previously reported data obtained with conventional texture analysis (image histogram, run-length matrix, co-occurrence matrix, autoregressive model, wavelet transform) on the same experimental material. Outlines, skeletons and original greyscale images were fractal analysed to evaluate possible significant differences in the measures values according to the analysed feature. In particular, and considering outline and skeleton as analysed features, fractal dimensions from compound 48/80 treated intestinal strips were significantly higher than the corresponding untreated ones (paired t and Wilcoxon test, p < 0.05), whereas corresponding lacunarity values were significantly lower (paired Wilcoxon test, p < 0.05) but only for outline as analysed feature. Outlines roughness increase is consistent with an increased granular mediators interface, favourable for their biological action; while lacunarity (image heterogeneity) reduction is consistent with the biological informative content decrease, due to granule content depletion. In spite of the significant differences in fractal dimension and lacunarity values registered according to the analysed feature (greyscale obtained values were, on average, lower than those obtained from outlines and skeletons; General Linear Model, p < 0.01), the discrimination power between not degranulated and degranulated MCs was, on average, the same and fully comparable with previously performed texture analysis on the same experimental material (outline and skeleton misclassification error, 20% [two false negative cases]; greyscale misclassification error, 30% [two false negative cases and one false positive case]). Fractal analysis proved to be a reliable and objective method for the characterization of MCs degranulation. PMID:25087582

  13. Mast cell degranulation by a hemolytic lipid toxin decreases GBS colonization and infection

    PubMed Central

    Gendrin, Claire; Vornhagen, Jay; Ngo, Lisa; Whidbey, Christopher; Boldenow, Erica; Santana-Ufret, Veronica; Clauson, Morgan; Burnside, Kellie; Galloway, Dionne P.; Waldorf, Kristina Adams; Piliponsky, Adrian M.; Rajagopal, Lakshmi

    2015-01-01

    Ascending infection of microbes from the lower genital tract into the amniotic cavity increases the risk of preterm birth, stillbirth, and newborn infections. Host defenses that are critical for preventing ascending microbial infection are not completely understood. Group B Streptococcus (GBS) are Gram-positive bacteria that frequently colonize the lower genital tract of healthy women but cause severe infections during pregnancy, leading to preterm birth, stillbirth, or early-onset newborn infections. We recently described that the GBS pigment is hemolytic, and increased pigment expression promotes GBS penetration of human placenta. Here, we show that the GBS hemolytic pigment/lipid toxin and hyperpigmented GBS strains induce mast cell degranulation, leading to the release of preformed and proinflammatory mediators. Mast cell–deficient mice exhibit enhanced bacterial burden, decreased neutrophil mobilization, and decreased immune responses during systemic GBS infection. In a vaginal colonization model, hyperpigmented GBS strains showed increased persistence in mast cell–deficient mice compared to mast cell–proficient mice. Consistent with these observations, fewer rectovaginal GBS isolates from women in their third trimester of pregnancy were hyperpigmented/hyperhemolytic. Our work represents the first example of a bacterial hemolytic lipid that induces mast cell degranulation and emphasizes the role of mast cells in limiting genital colonization by hyperpigmented GBS. PMID:26425734

  14. Differential Effects of Munc18s on Multiple Degranulation-Relevant Trans-SNARE Complexes

    PubMed Central

    Xu, Hao; Arnold, Matthew Grant; Kumar, Sushmitha Vijay

    2015-01-01

    Mast cell exocytosis, which includes compound degranulation and vesicle-associated piecemeal degranulation, requires multiple Q- and R- SNAREs. It is not clear how these SNAREs pair to form functional trans-SNARE complexes and how these trans-SNARE complexes are selectively regulated for fusion. Here we undertake a comprehensive examination of the capacity of two Q-SNARE subcomplexes (syntaxin3/SNAP-23 and syntaxin4/SNAP-23) to form fusogenic trans-SNARE complexes with each of the four granule-borne R-SNAREs (VAMP2, 3, 7, 8). We report the identification of at least six distinct trans-SNARE complexes under enhanced tethering conditions: i) VAMP2/syntaxin3/SNAP-23, ii) VAMP2/syntaxin4/SNAP-23, iii) VAMP3/syntaxin3/SNAP-23, iv) VAMP3/syntaxin4/SNAP-23, v) VAMP8/syntaxin3/SNAP-23, and vi) VAMP8/syntaxin4/SNAP-23. We show for the first time that Munc18a operates synergistically with SNAP-23-based non-neuronal SNARE complexes (i to iv) in lipid mixing, in contrast to Munc18b and c, which exhibit no positive effect on any SNARE combination tested. Pre-incubation with Munc18a renders the SNARE-dependent fusion reactions insensitive to the otherwise inhibitory R-SNARE cytoplasmic domains, suggesting a protective role of Munc18a for its cognate SNAREs. Our findings substantiate the recently discovered but unexpected requirement for Munc18a in mast cell exocytosis, and implicate post-translational modifications in Munc18b/c activation. PMID:26384026

  15. Hemichannels Are Required for Amyloid ?-Peptide-Induced Degranulation and Are Activated in Brain Mast Cells of APPswe/PS1dE9 Mice.

    PubMed

    Harcha, Paloma A; Vargas, Aníbal; Yi, Chenju; Koulakoff, Annette A; Giaume, Christian; Sáez, Juan C

    2015-06-24

    Mast cells (MCs) store an array of proinflammatory mediators in secretory granules that are rapidly released upon activation by diverse conditions including amyloid beta (A?) peptides. In the present work, we found a rapid degranulation of cultured MCs through a pannexin1 hemichannel (Panx1 HC)-dependent mechanism induced by A?25-35 peptide. Accordingly, A?25-35 peptide also increased membrane current and permeability, as well as intracellular Ca(2+) signal, mainly via Panx1 HCs because all of these responses were drastically inhibited by Panx1 HC blockers and absent in the MCs of Panx1(-/-) mice. Moreover, in acute coronal brain slices of control mice, A?25-35 peptide promoted both connexin 43 (Cx43)- and Panx1 HC-dependent MC dye uptake and histamine release, responses that were only Cx43 HC dependent in Panx1(-/-) mice. Because MCs have been found close to amyloid plaques of patients with Alzheimer's disease (AD), their distribution in brain slices of APPswe/PS1dE9 mice, a murine model of AD, was also investigated. The number of MCs in hippocampal and cortical areas increased drastically even before amyloid plaque deposits became evident. Therefore, MCs might act as early sensors of amyloid peptide and recruit other cells to the neuroinflammatory response, thus playing a critical role in the onset and progression of AD. PMID:26109673

  16. A neutrophil intrinsic impairment affecting Rab27a and degranulation in cystic fibrosis is corrected by CFTR potentiator therapy.

    PubMed

    Pohl, Kerstin; Hayes, Elaine; Keenan, Joanne; Henry, Michael; Meleady, Paula; Molloy, Kevin; Jundi, Bakr; Bergin, David A; McCarthy, Cormac; McElvaney, Oliver J; White, Michelle M; Clynes, Martin; Reeves, Emer P; McElvaney, Noel G

    2014-08-14

    Studies have endeavored to reconcile whether dysfunction of neutrophils in people with cystic fibrosis (CF) is a result of the genetic defect or is secondary due to infection and inflammation. In this study, we illustrate that disrupted function of the CF transmembrane conductance regulator (CFTR), such as that which occurs in patients with ?F508 and/or G551D mutations, correlates with impaired degranulation of antimicrobial proteins. We demonstrate that CF blood neutrophils release less secondary and tertiary granule components compared with control cells and that activation of the low-molecular-mass GTP-binding protein Rab27a, involved in the regulation of granule trafficking, is defective. The mechanism leading to impaired degranulation involves altered ion homeostasis caused by defective CFTR function with increased cytosolic levels of chloride and sodium, yet decreased magnesium measured in CF neutrophils. Decreased magnesium concentration in vivo and in vitro resulted in significantly decreased levels of GTP-bound Rab27a. Treatment of G551D patients with the ion channel potentiator ivacaftor resulted in normalized neutrophil cytosolic ion levels and activation of Rab27a, thereby leading to increased degranulation and bacterial killing. Our results confirm that intrinsic alterations of circulating neutrophils from patients with CF are corrected by ivacaftor, thus illustrating additional clinical benefits for CFTR modulator therapy. PMID:24934256

  17. Enhanced innate immune responses in a brood parasitic cowbird species: degranulation and oxidative burst

    USGS Publications Warehouse

    Hahn, D. Caldwell; Summers, Scott G.; Genovese, Kenneth J.; He, Haiqi; Kogut, Michael H.

    2013-01-01

    We examined the relative effectiveness of two innate immune responses in two species of New World blackbirds (Passeriformes, Icteridae) that differ in resistance to West Nile virus (WNV). We measured degranulation and oxidative burst, two fundamental components of phagocytosis, and we predicted that the functional effectiveness of these innate immune responses would correspond to the species' relative resistance to WNV. The brown-headed cowbird (Molothrus ater), an obligate brood parasite, had previously shown greater resistance to infection with WNV, lower viremia and faster recovery when infected, and lower subsequent antibody titers than the red-winged blackbird (Agelaius phoeniceus), a close relative that is not a brood parasite. We found that cowbird leukocytes were significantly more functionally efficient than those of the blackbird leukocytes and 50% more effective at killing the challenge bacteria. These results suggest that further examination of innate immunity in the cowbird may provide insight into adaptations that underlie its greater resistance to WNV. These results support an eco-immunological interpretation that species like the cowbird, which inhabit ecological niches with heightened exposure to parasites, experience evolutionary selection for more effective immune responses.

  18. Omega-3 Fatty Acids Modulate Weibel-Palade Body Degranulation and Actin Cytoskeleton Rearrangement in PMA-Stimulated Human Umbilical Vein Endothelial Cells

    PubMed Central

    Bürgin-Maunder, Corinna S.; Brooks, Peter R.; Russell, Fraser D.

    2013-01-01

    Long chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) produce cardiovascular benefits by improving endothelial function. Endothelial cells store von Willebrand factor (vWF) in cytoplasmic Weibel-Palade bodies (WPBs). We examined whether LC n-3 PUFAs regulate WPB degranulation using cultured human umbilical vein endothelial cells (HUVECs). HUVECs were incubated with or without 75 or 120 µM docosahexaenoic acid or eicosapentaenoic acid for 5 days at 37 °C. WPB degranulation was stimulated using phorbol 12-myristate 13-acetate (PMA), and this was assessed by immunocytochemical staining for vWF. Actin reorganization was determined using phalloidin-TRITC staining. We found that PMA stimulated WPB degranulation, and that this was significantly reduced by prior incubation of cells with LC n-3 PUFAs. In these cells, WPBs had rounded rather than rod-shaped morphology and localized to the perinuclear region, suggesting interference with cytoskeletal remodeling that is necessary for complete WPB degranulation. In line with this, actin rearrangement was altered in cells containing perinuclear WPBs, where cells exhibited a thickened actin rim in the absence of prominent cytoplasmic stress fibers. These findings indicate that LC n-3 PUFAs provide some protection against WBP degranulation, and may contribute to an improved understanding of the anti-thrombotic effects previously attributed to LC n-3 PUFAs. PMID:24217286

  19. Rosette Nanotubes Alter IgE-Mediated Degranulation in the Rat Basophilic Leukemia (RBL)-2H3 Cell Line.

    PubMed

    Ede, James D; Ortega, Van A; Boyle, David; Beingessner, Rachel L; Hemraz, Usha D; Fenniri, Hicham; Stafford, James L; Goss, Greg G

    2015-11-01

    In this study, the effects of rosette nanotube (RNT) exposure on immune cell viability and function were investigated in vitro using the rat basophilic leukemia (RBL)-2H3 cell line. RBL-2H3 viability was decreased in a dose- and time-dependent manner after lysine-functionalized RNT (K-RNT) exposure. In addition, K-RNTs had a significant effect on RBL-2H3 degranulation. When K-RNT exposure was concurrent with IgE sensitization, 50 and 100?mg?l(-1) K-RNTs elicited a heightened degranulatory response compared with IgE alone. Exposure to 50 and 100?mg?l(-1) K-RNTs also caused degranulation in RBL-2H3 cells not sensitized with IgE (0?ng?ml(-1) IgE). Furthermore, in cells preexposed to K-RNTs for 2 h and subsequently washed, sensitized, and stimulated with IgE, a potentiated degranulatory response was observed. Using confocal laser scanning microscopy and a fluorescein isothiocyanate (FITC)-functionalized RNT construct (termed FITC(1)/TBL(19)-RNT), we demonstrated a strong and direct affiliation between RNTs and RBL-2H3 cell membranes. We also demonstrated cellular internalization of RNTs after 2?h of exposure. Together, these data demonstrate that RNTs may affiliate with the cellular membrane of RBL-2H3 cells and can be internalized. These interactions can affect viability and alter the ability of these cells to elicit IgE-Fc?R mediated degranulation. PMID:26224082

  20. [Basic peptides from bee venom, IV. Synthesis of the mast cell-degranulating peptide by liquid-phase fragment condensation (author's transl)].

    PubMed

    Hartter, P

    1980-04-01

    The synthesis of the mast cell-degranulating peptide by liquid-phase fragment condensation is described. After the carboxyterminal of the peptide is condensated with polyethylene-glycol (Mr 10000) the following fragments are coupled stepwise on the polymer, a soluble carrier in dichloromethane by the dicyclohexylcarbodiimide/hydroxybenzotriazole-method. Pos. 17-21 Boc-Lys(Z)-Ile-Cys(SiPr)-Gly-Lys(Z) (I) Pos. 12-16 Boc-Pro-His(Trt)-Ile-Cys(Trt)-Arg(Tos) (II) Pos. 8-11 Boc-His(Trt)-Val-Ile-Lys(Z) (III) Pos. 5-7 Boc-Cys(SiPr)-Lys(Z)-Arg(Tos) (IV) Pos. 1-4 Boc-Ile-Lys(Z)-Cys(Trt)-Asn(Mbh) (V) It is practical to crystallize the polyethyleneglycol peptide-coupling products from ethanol after each step. Most of the protecting groups can be removed by treatment of the complete polyethylene-glycol-peptide in trifluoroacetic acid/HBr. In methanol, saturated with ammonia, the peptide is removed in the amid-form from the carrier. The guanidyl-blocking group disappears by solving the peptide in liquid HF. The crude peptide is converted into the tetra-S-sulfonate derivate by oxidative sulfitolysis and purified by ion-exchange and gel chromatography. After reduction by mercaptoethanol a cautious air-reoxidation of the SH- to the SS-peptide followed. Rechromatography on ion-exchange and dextran gels yields a peptide with good biological activity in rat cell histamin-liberation and inflammation inhibition compared with the natural recombinated product. PMID:7380391

  1. Rheumatoid arthritis synovial fluid phospholipase A2 activating protein (PLAP) stimulates human neutrophil degranulation and superoxide ion production.

    PubMed

    Bomalaski, J S; Baker, D; Resurreccion, N V; Clark, M A

    1989-06-01

    Rheumatoid arthritis is characterized by excessive eicosanoid production, and phospholipase enzymes are the rate limiting step in eicosanoid synthesis. We have shown previously that cells from patients with rheumatoid arthritis express enhanced phospholipase A2 enzyme activities. Recently, we have isolated a phospholipase A2 activating protein termed PLAP from rheumatoid synovial fluid. This novel human protein shares biochemical and antigenic similarities with melittin, a bee venom phospholipase activating protein. Because melittin has been shown to induce neutrophil degranulation and superoxide formation, and because exuberent release of lysosomal enzymes and superoxide have been implicated in the pathogenesis of rheumatoid arthritis, we examined the role of PLAP on inducing these neutrophil functions. PMID:2552770

  2. The antigen-induced degranulation of basophil leucocytes from atopic subjects, studied by phase-contrast microscopy

    PubMed Central

    Hastie, R.

    1971-01-01

    A type of microscopical chamber is described which enables monolayers of cells to be examined at 37°C by phase-contrast microscopy at high magnification and which can be perfused semi-automatically. Such chambers have been used to observe morphological changes in the basophil leucocytes of atopic subjects when challenged with an extract of Timothy grass pollen. The appearance of basophil leucocytes in monolayers prepared from both washed and defibrinated blood cell suspensions has been studied. Basophils taken from non-atopic subjects or atopic subjects who were not hypersensitive to grass pollen showed no reaction to Timothy grass pollen extract. By contrast, basophils taken from pollen sensitive atopic subjects reacted to Timothy grass pollen extract with an acute change in motility and many degranulated. The morphological changes observed are described and illustrated in detail. No significant changes were seen in other types of cell. Some immunological and cellular mechanisms which may underlie this degranulation of human basophil leucocytes are discussed. ImagesFIG. 2FIG. 3FIG. 4 PMID:4924942

  3. Polydatin (PD) inhibits IgE-mediated passive cutaneous anaphylaxis in mice by stabilizing mast cells through modulating Ca{sup 2+} mobilization

    SciTech Connect

    Yuan, Meichun; Department of Physiology, Hubei University of Medicine, Shiyan ; Li, Jianjie; Lv, Jingzhang; Mo, Xucheng; Yang, Chengbin; Chen, Xiangdong; Liu, Zhigang; Liu, Jie

    2012-11-01

    Mast cells play a key role in the pathogenesis of asthma and are a promising target for therapeutic intervention in asthma. This study investigated the effects of polydatin (PD), a resveratrol glucoside, on mast cell degranulation upon cross-linking of the high-affinity IgE receptors (Fc?RI), as well as the anti-allergic activity of PD in vivo. Herein, we demonstrated that PD treatment for 30 min suppressed Fc?RI-mediated mast cell degranulation in a dose-dependent manner. Concomitantly, PD significantly decreased Fc?RI-mediated Ca{sup 2+} increase in mast cells. The suppressive effects of PD on Fc?RI-mediated Ca{sup 2+} increase were largely inhibited by using LaCl{sub 3} to block the Ca{sup 2+} release-activated Ca{sup 2+} channels (CRACs). Furthermore, PD significantly inhibited Ca{sup 2+} entry through CRACs evoked by thapsigargin (TG). Knocking down protein expression of Orai1, the pore-forming subunit of CRACs, significantly decreased PD suppression of Fc?RI-induced intracellular Ca{sup 2+} influx and mast cell degranulation. In a mouse model of mast cell-dependent passive cutaneous anaphylaxis (PCA), in vivo PD administration suppressed mast cell degranulation and inhibited anaphylaxis. Taken together, our data indicate that PD stabilizes mast cells by suppressing Fc?RI-induced Ca{sup 2+} mobilization mainly through inhibiting Ca{sup 2+} entry via CRACs, thus exerting a protective effect against PCA. -- Highlights: ? Polydatin can prevent the pathogenesis of passive cutaneous anaphylaxis in mice. ? Polydatin stabilizes mast cells by decreasing Fc?RI-mediated degranulation. ? Polydatin suppresses Ca{sup 2+} entry through CRAC channels in mast cells.

  4. Novel phenotype in beagle dogs characterized by skin response to compound 48/80 focusing on skin mast cell degranulation.

    PubMed

    Uchida, Mitsuhiro; Ito, Fumi; Tsuchiya, Toshiyuki; Shoji, Yoko; Kurosawa, Toru

    2015-10-23

    Beagle dogs have long been employed in toxicology studies and as skin disease models. Compared with other experimental animal species, they are known to be susceptible to skin responses, such as rashes, from exposure to various chemical compounds. Here, a unique dog phenotype was identified that showed no skin response to compound 48/80, a mast cell degranulating agent. Although the skin responses to intradermal injection of polyoxyethylene castor oil derivative (HCO-60, a nonionic detergent), histamine dihydrochloride, concanavalin A (IgE receptor-mediated stimuli), or calcium ionophore A23187 were comparable in wild-type (WT) dogs and these nonresponder (NR) dogs, only the response to compound 48/80 was entirely absent from NR dogs. The skin mast cell density and histamine content per mast cell were histologically comparable between WT and NR dogs. By checking for skin responses to compound 48/80, NR dogs were found to exist at the proportion of 17-20% among four animal breeders. From retrospective analysis of in-house breeding histories, the NR phenotype appears to conform to the Mendelian pattern of recessive inheritance. The standard skin response in WT dogs developed at 2-4 months of age. In conclusion, this unique phenotype, typified by insensitivity in the compound 48/80-induced degranulation pathway in mast cells, has been widely retained by recessive inheritance in beagle dogs among general experimental animal breeders. The knowledge concerning this phenotype could lead to better utilization of dogs in studies and aid in model development. PMID:26062768

  5. Novel phenotype in beagle dogs characterized by skin response to compound 48/80 focusing on skin mast cell degranulation

    PubMed Central

    Uchida, Mitsuhiro; Ito, Fumi; Tsuchiya, Toshiyuki; Shoji, Yoko; Kurosawa, Toru

    2015-01-01

    Beagle dogs have long been employed in toxicology studies and as skin disease models. Compared with other experimental animal species, they are known to be susceptible to skin responses, such as rashes, from exposure to various chemical compounds. Here, a unique dog phenotype was identified that showed no skin response to compound 48/80, a mast cell degranulating agent. Although the skin responses to intradermal injection of polyoxyethylene castor oil derivative (HCO-60, a nonionic detergent), histamine dihydrochloride, concanavalin A (IgE receptor-mediated stimuli), or calcium ionophore A23187 were comparable in wild-type (WT) dogs and these nonresponder (NR) dogs, only the response to compound 48/80 was entirely absent from NR dogs. The skin mast cell density and histamine content per mast cell were histologically comparable between WT and NR dogs. By checking for skin responses to compound 48/80, NR dogs were found to exist at the proportion of 17–20% among four animal breeders. From retrospective analysis of in-house breeding histories, the NR phenotype appears to conform to the Mendelian pattern of recessive inheritance. The standard skin response in WT dogs developed at 2–4 months of age. In conclusion, this unique phenotype, typified by insensitivity in the compound 48/80-induced degranulation pathway in mast cells, has been widely retained by recessive inheritance in beagle dogs among general experimental animal breeders. The knowledge concerning this phenotype could lead to better utilization of dogs in studies and aid in model development. PMID:26062768

  6. Inhibition of Fc epsilon-RI-mediated activation of rat basophilic leukemia cells by Clostridium difficile toxin B (monoglucosyltransferase)

    PubMed

    Prepens, U; Just, I; von Eichel-Streiber, C; Aktories, K

    1996-03-29

    Treatment of rat basophilic leukemia (RBL) 2H3-hm1 cells with Clostridium difficile toxin B (2 ng/ml), which reportedly depolymerizes the actin cytoskeleton, blocked [3H]serotonin release induced by 2,4-dinitrophenyl-bovine serum albumin, carbachol, mastoparan, and reduced ionophore A23187-stimulated degranulation by about 55-60%. In lysates of RBL cells, toxin B 14C-glucosylated two major and one minor protein. By using two-dimensional gel electrophoresis and immunoblotting, RhoA and Cdc42 were identified as protein substrates of toxin B. In contrast to toxin B, Clostridium botulinum transferase C3 that selectively inactivates RhoA by ADP-ribosylation did not inhibit degranulation up to a concentration of 150 microg/ml. Antigen-stimulated tyrosine phosphorylation of a 110-kDa protein was inhibited by toxin B as well as by the phosphatidylinositol 3-kinase inhibitor wortmannin. Depolymerization of the microfilament cytoskeleton of RBL cells by C. botulinum C2 toxin or cytochalasin D resulted in an increased [3H]serotonin release induced by antigen, carbachol, mastoparan, or by calcium ionophore A23187, but without affecting toxin B-induced inhibition of degranulation. The data indicate that toxin B inhibits activation of RBL cells by glucosylation of low molecular mass GTP-binding proteins of the Rho subfamily (most likely Cdc42) by a mechanism not involving the actin cytoskeleton. PMID:8631752

  7. Britanin Suppresses IgE/Ag-Induced Mast Cell Activation by Inhibiting the Syk Pathway

    PubMed Central

    Lu, Yue; Li, Xian; Park, Young Na; Kwon, Okyun; Piao, Donggen; Chang, Young-Chae; Kim, Cheorl-Ho; Lee, Eunkyung; Son, Jong Keun; Chang, Hyeun Wook

    2014-01-01

    The aim of this study was to determine whether britanin, isolated from the flowers of Inula japonica (Inulae Flos), modulates the generation of allergic inflammatory mediators in activated mast cells. To understand the biological activity of britanin, the authors investigated its effects on the generation of prostaglandin D2 (PGD2), leukotriene C4 (LTC4), and degranulation in IgE/Ag-induced bone marrow-derived mast cells (BMMCs). Britanin dose dependently inhibited degranulation and the generations of PGD2 and LTC4 in BMMCs. Biochemical analyses of IgE/Ag-mediated signaling pathways demonstrated that britanin suppressed the phosphorylation of Syk kinase and multiple downstream signaling processes, including phospholipase C?1 (PLC?1)-mediated calcium influx, the activation of mitogen-activated protein kinases (MAPKs; extracellular signal-regulated kinase 1/2, c-Jun NH2-terminal kinase and p38), and the nuclear factor-?B (NF-?B) pathway. Taken together, the findings of this study suggest britanin suppresses degranulation and eicosanoid generation by inhibiting the Syk-dependent pathway and britanin might be useful for the treatment of allergic inflammatory diseases. PMID:25009699

  8. Spontaneous locomotor activity correlates with the degranulation of mast cells in the meninges rather than in the thalamus: Disruptive effect of cocaine

    PubMed Central

    Larson, Alice A.; Thomas, Mark J.; McElhose, Alex; Kovács, Katalin J.

    2011-01-01

    Mast cells are located in the central nervous system (CNS) of many mammals and stress induces their degranulation. We postulated that mast cells are associated with wakefulness and stimulatory tone in the CNS, as reflected by spontaneous motor activity. Because stress also precipitates drug-seeking behavior in cocaine addicts, we also postulated that cocaine manifests its effects through this relationship. We investigated the influence of single and repeated injections of cocaine on circulating corticosterone, motor activity and degranulation of mast cells in both the thalamus and meninges of mice. Mice were subjected to 5 consecutive days of cocaine or saline followed by a single injection of cocaine or saline 11 days later. Spontaneous locomotor activity was measure for one hour after the final injection before death. Neither a single injection nor prior treatment with cocaine increased motor activity compared to saline-injected controls, however, repeated administration of cocaine induced a significant sensitization to its behavioral effect when delivered 11 days later. In mice that received only saline, motor activity correlated positively with mast cell degranulation in the meninges but not in the thalamus. Cocaine, regardless of the treatment schedule, disrupted this correlation. The concentration of corticosterone did not differ amongst groups and did not correlate with either behavior or mast cell parameters in any group. The correlation between behavioral activity and the mast cell degranulation in the meninges suggests that these parameters are linked. The disruptive effect of cocaine on this relationship indicates a role downstream from mast cells in the regulation of motor activity. PMID:21561602

  9. Helicobacter pylori Outer Membrane Vesicle Proteins Induce Human Eosinophil Degranulation via a ?2 Integrin CD11/CD18- and ICAM-1-Dependent Mechanism

    PubMed Central

    Ko, Su Hyuk; Jeon, Jong Ik; Kim, Young-Jeon; Yoon, Ho Joo; Kim, Hyeyoung; Kim, Nayoung; Kim, Joo Sung; Kim, Jung Mogg

    2015-01-01

    Eosinophil cationic protein (ECP), a cytotoxic protein contained in eosinophils granules, can contribute to various inflammatory responses. Although Helicobacter pylori infection increases infiltration of eosinophils, the mechanisms of eosinophil degranulation by H. pylori infection are largely unknown. The goal of this study was to investigate the role of H. pylori outer membrane vesicles (OMVs) in modulating eosinophil degranulation. We found that eosinophils treated with H. pylori OMVs released significantly more ECP compared with untreated controls. In addition, eosinophils cocultured with OMV-preexposed primary gastric epithelial cells exhibited significantly increased ECP release. Similarly, eosinophils cocultured with culture supernatant (CM) from primary gastric epithelial cells exposed to OMVs (OMV-CM) released significantly higher amounts of ECP compared with eosinophils cocultured with CM from unexposed control cells. Furthermore, OMVs and OMV-CM both induced the upregulation of ICAM-1 on gastric epithelial cells and ?2 integrin CD11b on eosinophils. In addition, both transduction of ICAM-1 shRNA into gastric epithelial cells and treatment with neutralizing mAbs to CD18 significantly decreased OMV-mediated or OMV-CM-mediated release of ECP. These results suggest that the eosinophil degranulation response to H. pylori OMVs occurs via a mechanism that is dependent on both ?2 integrin CD11/CD18 and ICAM-1. PMID:25821353

  10. ADP-ribose/TRPM2-mediated Ca2+ signaling is essential for cytolytic degranulation and antitumor activity of natural killer cells

    PubMed Central

    Rah, So-Young; Kwak, Jae-Yong; Chung, Yun-Jo; Kim, Uh-Hyun

    2015-01-01

    Natural killer (NK) cells are essential for immunosurveillance against transformed cells. Transient receptor potential melastatin 2 (TRPM2) is a Ca2+-permeable cation channel gated by ADP-ribose (ADPR). However, the role of TRPM2-mediated Ca2+ signaling in the antitumor response of NK cells has not been explored. Here, we show that ADPR-mediated Ca2+ signaling is important for cytolytic granule polarization and degranulation but not involved in target cell recognition by NK cells. The key steps of this pathway are: 1) the activation of intracellular CD38 by protein kinase A following the interaction of the NK cell with a tumor cell results in the production of ADPR, 2) ADPR targets TRPM2 channels on cytolytic granules, and 3) TRPM2-mediated Ca2+ signaling induces cytolytic granule polarization and degranulation, resulting in antitumor activity. NK cells treated with 8-Br-ADPR, an ADPR antagonist, as well as NK cells from Cd38?/? mice showed reduced tumor-induced granule polarization, degranulation, granzyme B secretion, and cytotoxicity of NK cells. Furthermore, TRPM2-deficient NK cells showed an intrinsic defect in tumoricidal activity. These results highlight CD38, ADPR, and TRPM2 as key players in the specialized Ca2+ signaling system involved in the antitumor activity of NK cells. PMID:25879940

  11. Tacrolimus hydrate ointment inhibits skin plasma extravasation in rats induced by topical m-xylene but not capsaicin.

    PubMed

    Goto, Shiho; Kondo, Fumio; Ikai, Yoshitomo; Miyake, Mio; Futamura, Masaki; Ito, Komei; Sakamoto, Tatsuo

    2009-04-17

    Tacrolimus ointment is used to treat various chronic inflammatory skin diseases. However, the effect of this ointment on acute neurogenic inflammation in the skin remains to be fully elucidated. Topical capsaicin and m-xylene produce tachykinin release from sensory nerves in the skin, resulting in skin plasma leakage. We investigated the effect of tacrolimus ointment (0.1%) on skin microvascular leakage induced by topical capsaicin (10 mM) and m-xylene (neat), and intracutaneous compound 48/80 (c48/80) (10 microg/ml, 50 microl/site) in two groups of rats pretreated with excessive capsaicin or its vehicle. The amount of leaked Evans blue dye reflected skin plasma leakage. Capsaicin, m-xylene or c48/80 was applied to the shaved abdomens of rats 8 h after topical application of tacrolimus ointment or its base. Desensitization with capsaicin reduced the skin response to capsaicin and m-xylene by 100% and 65%, respectively, but not to c48/80. Tacrolimus ointment significantly inhibited the skin response induced by m-xylene and c48/80, regardless of pretreatment with capsaicin. However, topical tacrolimus did not influence the skin response induced by capsaicin. We also evaluated whether topical capsaicin and m-xylene, and intracutaneous c48/80 cause mast cell degranulation in skin treated with tacrolimus. Mast cell degranulation was microscopically assessed. Topical tacrolimus only significantly suppressed degranulation induced by m-xylene and c48/80. Our data shows that tacrolimus ointment partially inhibits plasma leakage and mast cell degranulation in rat skin induced by m-xylene and c48/80 but not capsaicin, suggesting that the inhibitory effect is not associated with a reduction in neurogenic-mediated mechanisms. PMID:19258015

  12. No effect of a 30-h period of sleep deprivation on leukocyte trafficking, neutrophil degranulation and saliva IgA responses to exercise.

    PubMed

    Ricardo, J S Costa; Cartner, Louise; Oliver, Samuel J; Laing, Stewart J; Walters, Robert; Bilzon, James L J; Walsh, Neil P

    2009-02-01

    A one night period without sleep is not uncommon amongst athletes travelling across time zones and military personnel during training and operations. However, the effect of one night without sleep on immune indices in response to strenuous exercise remains unknown. The objective was to determine the effect of one night without sleep on immune indices in response to subsequent strenuous exercise. Using a repeated measures cross-over design, on one occasion eleven male participants slept normally (CON) and on another they were sleep deprived for 30 h (SDEP). After 30 h participants performed 30 min steady state (SS) treadmill exercise at 60% VO2max followed by a 30 min treadmill time trial (TT). Blood and saliva samples were collected at 0 h, 30 h, post-SS, post-TT, 2 h post-TT and 18 h post-TT. Circulating leukocyte and T-lymphocyte subset counts, bacterially-stimulated neutrophil degranulation, saliva secretory immunoglobulin A (S-IgA) and plasma cortisol were determined. No trial x time interactions were observed for immune indices and plasma cortisol. A leukocytosis, neutrophilia, and lymphocytosis was observed post-TT compared with 30 h (P < 0.01). Also, at post-TT compared with 30 h an increase in circulating T-lymphocyte CD3 + (55%) and CD8 + (67%) counts (P < 0.05), a decrease in neutrophil degranulation (20%; P < 0.05) and an increase in S-IgA concentration (83%) was observed (P < 0.01). Plasma cortisol concentration increased post-TT (62%) compared with post-SS (P < 0.01). In conclusion, a 30 h period of sleep deprivation does not alter leukocyte trafficking, neutrophil degranulation or S-IgA responses either at rest or after submaximal and strenuous exercise. PMID:19018559

  13. Mouse and human eosinophils degranulate in response to platelet-activating factor (PAF) and lysoPAF via a PAF-receptor-independent mechanism: evidence for a novel receptor.

    PubMed

    Dyer, Kimberly D; Percopo, Caroline M; Xie, Zhihui; Yang, Zhao; Kim, John Dongil; Davoine, Francis; Lacy, Paige; Druey, Kirk M; Moqbel, Redwan; Rosenberg, Helene F

    2010-06-01

    Platelet-activating factor (PAF [1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine]) is a phospholipid mediator released from activated macrophages, mast cells, and basophils that promotes pathophysiologic inflammation. Eosinophil responses to PAF are complex and incompletely elucidated. We show in this article that PAF and its 2-deacetylated metabolite (lysoPAF) promote degranulation (release of eosinophil peroxidase) via a mechanism that is independent of the characterized PAFR. Specifically, we demonstrate that receptor antagonists CV-3988 and WEB-2086 and pertussis toxin have no impact on PAF- or lysoPAF-mediated degranulation. Furthermore, cultured mouse eosinophils from PAFR(-/-) bone marrow progenitors degranulate in response to PAF and lysoPAF in a manner indistinguishable from their wild-type counterparts. In addition to PAF and lysoPAF, human eosinophils degranulate in response to lysophosphatidylcholine, but not phosphatidylcholine, lysophosphatidylethanolamine, or phosphatidylethanolamine, demonstrating selective responses to phospholipids with a choline head-group and minimal substitution at the sn-2 hydroxyl. Human eosinophils release preformed cytokines in response to PAF, but not lysoPAF, also via a PAFR-independent mechanism. Mouse eosinophils do not release cytokines in response to PAF or lysoPAF, but they are capable of doing so in response to IL-6. Overall, our work provides the first direct evidence for a role for PAF in activating and inducing degranulation of mouse eosinophils, a crucial feature for the interpretation of mouse models of PAF-mediated asthma and anaphylaxis. Likewise, we document and define PAF and lysoPAF-mediated activities that are not dependent on signaling via PAFR, suggesting the existence of other unexplored molecular signaling pathways mediating responses from PAF, lysoPAF, and closely related phospholipid mediators. PMID:20421642

  14. Macelignan inhibits histamine release and inflammatory mediator production in activated rat basophilic leukemia mast cells.

    PubMed

    Han, Young Sun; Kim, Myung-Suk; Hwang, Jae-Kwan

    2012-10-01

    Type I allergy is characterized by the release of granule-associated mediators, lipid-derived substances, cytokines, and chemokines by activated mast cells. To evaluate the anti-allergic effects of macelignan isolated from Myristica fragrans Houtt., we determined its ability to inhibit calcium (Ca(2+)) influx, degranulation, and inflammatory mediator production in RBL-2 H3 cells stimulated with A23187 and phorbol 12-myristate 13-acetate. Macelignan inhibited Ca(2+) influx and the secretion of ?-hexosaminidase, histamine, prostaglandin E(2), and leukotriene C(4); decreased mRNA levels of cyclooxygenase-2, 5-lipoxygenase, interleukin-4 (IL-4), IL-13, and tumor necrosis factor-?; and attenuated phosphorylation of Akt and the mitogen-activated protein kinases extracellular signal-regulated kinase, p38, and c-Jun N-terminal kinase. These results indicate the potential of macelignan as a type I allergy treatment. PMID:22729280

  15. Effect of Scrophularia buergeriana extract on the degranulation of mast cells and ear swelling induced by dinitrofluorobenzene in mice.

    PubMed

    Kim, Jin-Kyung; Kim, Yoon Hee; Lee, Hee Hwan; Lim, Soon Sung; Park, Kyung Woo

    2012-02-01

    Scrophularia buergeriana Miquel (Scrophulariaceae, SB) is a biennial plant native to Korea, northern China, and Japan that plays an important role in traditional medicine. The dried root of SB has long been used in oriental medicine for treatment of fever, swelling, constipation, pharyngitis, neuritis, and laryngitis. In the present study, we evaluated the ethanol extract of SB (SBE) to determine if it exerted any anti-allergic effects that had not previously been demonstrated. SBE markedly inhibited ?-hexosaminidase and histamine release and suppressed the expression of tumor necrosis factor-? and interleukin-4 cytokines by RBL-2H3 mast cells. In addition, topical treatment with SBE effectively reduced allergic inflammation in a dinitrofluorobenzene-induced contact hypersensitivity mouse model. These results strongly suggest that SBE is a promising source of anti-allergic agents. PMID:21318391

  16. Cloning and characterization analysis of the genes encoding precursor of mast cell degranulating peptide from 2 honeybee and 3 wasp species.

    PubMed

    Zhang, Su-Fang; Shi, Wan-Jun; Cheng, Jia-An; Zhang, Chuan-Xi

    2003-09-01

    The precursors of mast cell degranulating peptide (MCDP) genes were amplified by RT-PCR from the total RNA of venom gland of two honeybee species, Apis mellifera ligustica, Apis cerana cerana, and three wasp species, Vespa magnifica, Vespa velutina nigrothorax and Polistes hebraeus, respectively. Their PCR products were ligated into pGEM T-easy vector and the nucleotide sequences were analyzed. The length of five fragments was the same, it was 341 bp containing an ORF of 153 bp coding the precursor of MCDP and 188 bp 3' noncoding region. They have more than 90% homologues with each other in nucleotide sequences. The precursors of MCDP of A. cerana cerana, V. magnifica, V. velutina nigrothorax and P. hebraeus shared 96%, 100%, 94% and 98% homology with A. mellifera ligustica, respectively. The two species of wasps, V. magnifica and V. velutina nigrothorax, contained the same MCDP as A. mellifera ligustica, though they belong to different families with quite different biological properties, while A. cerana cerana contained the different MCDP in their venom as A. mellifera ligustica though they belong to the same genus. The fifth amino acid residue of MCDP in A. cerana cerana and P. hebraeus is arginine, replacing the cysteine, an important disulfide bridges element, in the position as in A. mellifera ligustica. PMID:14577379

  17. Chronic Insulin Exposure Induces ER Stress and Lipid Body Accumulation in Mast Cells at the Expense of Their Secretory Degranulation Response

    PubMed Central

    Balajadia, Januaria; Shimoda, Lori M. N.; Sung, Carl; Turner, Helen

    2015-01-01

    Lipid bodies (LB) are reservoirs of precursors to inflammatory lipid mediators in immunocytes, including mast cells. LB numbers are dynamic, increasing dramatically under conditions of immunological challenge. We have previously shown in vitro that insulin-influenced lipogenic pathways induce LB biogenesis in mast cells, with their numbers attaining steatosis-like levels. Here, we demonstrate that in vivo hyperinsulinemia resulting from high fat diet is associated with LB accumulation in murine mast cells and basophils. We characterize the lipidome of purified insulin-induced LB, and the shifts in the whole cell lipid landscape in LB that are associated with their accumulation, in both model (RBL2H3) and primary mast cells. Lipidomic analysis suggests a gain of function associated with LB accumulation, in terms of elevated levels of eicosanoid precursors that translate to enhanced antigen-induced LTC4 release. Loss-of-function in terms of a suppressed degranulation response was also associated with LB accumulation, as were ER reprogramming and ER stress, analogous to observations in the obese hepatocyte and adipocyte. Taken together, these data suggest that chronic insulin elevation drives mast cell LB enrichment in vitro and in vivo, with associated effects on the cellular lipidome, ER status and pro-inflammatory responses. PMID:26263026

  18. Analysis of Phosphorylation-dependent Protein Interactions of Adhesion and Degranulation Promoting Adaptor Protein (ADAP) Reveals Novel Interaction Partners Required for Chemokine-directed T cell Migration.

    PubMed

    Kuropka, Benno; Witte, Amelie; Sticht, Jana; Waldt, Natalie; Majkut, Paul; Hackenberger, Christian P R; Schraven, Burkhart; Krause, Eberhard; Kliche, Stefanie; Freund, Christian

    2015-11-01

    Stimulation of T cells leads to distinct changes of their adhesive and migratory properties. Signal propagation from activated receptors to integrins depends on scaffolding proteins such as the adhesion and degranulation promoting adaptor protein (ADAP)(1). Here we have comprehensively investigated the phosphotyrosine interactome of ADAP in T cells and define known and novel interaction partners of functional relevance. While most phosphosites reside in unstructured regions of the protein, thereby defining classical SH2 domain interaction sites for master regulators of T cell signaling such as SLP76, Fyn-kinase, and NCK, other binding events depend on structural context. Interaction proteomics using different ADAP constructs comprising most of the known phosphotyrosine motifs as well as the structured domains confirm that a distinct set of proteins is attracted by pY571 of ADAP, including the ?-chain-associated protein kinase of 70 kDa (ZAP70). The interaction of ADAP and ZAP70 is inducible upon stimulation either of the T cell receptor (TCR) or by chemokine. NMR spectroscopy reveals that the N-terminal SH2 domains within a ZAP70-tandem-SH2 construct is the major site of interaction with phosphorylated ADAP-hSH3(N) and microscale thermophoresis (MST) indicates an intermediate binding affinity (Kd = 2.3 ?m). Interestingly, although T cell receptor dependent events such as T cell/antigen presenting cell (APC) conjugate formation and adhesion are not affected by mutation of Y571, migration of T cells along a chemokine gradient is compromised. Thus, although most phospho-sites in ADAP are linked to T cell receptor related functions we have identified a unique phosphotyrosine that is solely required for chemokine induced T cell behavior. PMID:26246585

  19. Once Phosphorylated, Tyrosines in Carboxyl Terminus of Protein-tyrosine Kinase Syk Interact with Signaling Proteins, Including TULA-2, a Negative Regulator of Mast Cell Degranulation*

    PubMed Central

    de Castro, Rodrigo Orlandini; Zhang, Juan; Groves, Jacqueline R.; Barbu, Emilia Alina; Siraganian, Reuben P.

    2012-01-01

    Activation of the high affinity IgE-binding receptor (Fc?RI) results in the tyrosine phosphorylation of two conserved tyrosines located close to the COOH terminus of the protein-tyrosine kinase Syk. Synthetic peptides representing the last 10 amino acids of the tail of Syk with these two tyrosines either nonphosphorylated or phosphorylated were used to precipitate proteins from mast cell lysates. Proteins specifically precipitated by the phosphorylated peptide were identified by mass spectrometry. These included the adaptor proteins SLP-76, Nck-1, Grb2, and Grb2-related adaptor downstream of Shc (GADS) and the protein phosphatases SHIP-1 and TULA-2 (also known as UBASH3B or STS-1). The presence of these in the precipitates was further confirmed by immunoblotting. Using the peptides as probes in far Western blots showed direct binding of the phosphorylated peptide to Nck-1 and SHIP-1. Immunoprecipitations suggested that there were complexes of these proteins associated with Syk especially after receptor activation; in these complexes are Nck, SHIP-1, SLP-76, Grb2, and TULA-2 (UBASH3B or STS-1). The decreased expression of TULA-2 by treatment of mast cells with siRNA increased the Fc?RI-induced tyrosine phosphorylation of the activation loop tyrosines of Syk and the phosphorylation of phospholipase C-?2. There was parallel enhancement of the receptor-induced degranulation and activation of nuclear factor for T cells or nuclear factor ?B, indicating that TULA-2, like SHIP-1, functions as a negative regulator of Fc?RI signaling in mast cells. Therefore, once phosphorylated, the terminal tyrosines of Syk bind complexes of proteins that are positive and negative regulators of signaling in mast cells. PMID:22267732

  20. Chromaffin cells in the adrenal homolog of Aphanius fasciatus (teleost fish) express piecemeal degranulation in response to osmotic stress: a hint for a conservative evolutionary process.

    PubMed

    Crivellato, Enrico; Civinini, Annalena; Gallo, Valentina Patrizia

    2006-10-01

    The effect of severe osmotic stress on the ultrastructural morphology of chromaffin cells in the adrenal homolog of Aphanius fasciatus, a small eurhyaline teleost living in saltpans, was evaluated by electron microscopy quantitative analysis. Fishes were transferred from salt water, whose salinity was 3.7%, to dechlorinated tap water and chromaffin cells were studied at resting condition and after 2 and 48 hr from the beginning of the experiment. Ultrastructural examination revealed a series of granule and cytoplasmic changes highly specific for piecemeal degranulation (PMD), a secretory process based on vesicular transport of cargoes from within granules for extracellular release, which was previously described in chromaffin cells of the mouse, rat, and human adrenal medulla. There was indeed a significant trend toward loss of content material from chromaffin granules accompanied by enlargement of granule size. Remarkably, chromaffin granules maintained their individual close structure during the whole releasing process and eventually transformed into large empty containers. A dramatic increase in the density of small, membrane-bound, variably electron-dense vesicles free in the cytoplasm or attached to granules was recognized during the first 2 hr of stress response. These features fell to control levels after 48 hr. A similar time-course pattern was observed concerning the formation of budding projections from the surface of chromaffin granules. This study provides new insight into PMD physiology and suggests that PMD is part of an adaptive secretory response to severe osmotic stress in fishes. From an evolutionary point of view, this study lends support to the concept that PMD is a secretory mechanism highly conserved throughout vertebrate classes. PMID:16964607

  1. Inhibition of interferon-gamma signaling by a mercurio-substituted dihydropsoralen in murine keratinocytes.

    PubMed

    Martey, Christine A; Vetrano, Anna M; Whittemore, Marilyn S; Mariano, Thomas M; Heck, Diane E; Laskin, Debra L; Heindel, Ned D; Laskin, Jeffrey D

    2005-12-01

    Psoralens and ultraviolet light A (PUVA) are used in the treatment of a variety of epidermal proliferative and inflammatory disorders. These compounds are known to intercalate and photo crosslink DNA. Specific receptor proteins for psoralens have also been identified. We describe a novel activity of a thiol reactive derivative, iodomercurio-4',5'-dihydrotrimethylpsoralen (iodomercurio-H2TMP) in keratinocytes. Without UVA, this psoralen was found to be an effective inhibitor of interferon-gamma (IFN-gamma)-signaling as measured by induction of nitric oxide biosynthesis (IC50 = 0.8 microM). This activity was increased (IC50 = 0.1 microM) when the cells were depleted of intracellular glutathione (GSH) with buthionine sulfoximine. In keratinocytes, IFN-gamma stimulates expression of inducible nitric oxide synthase (NOS2). Although iodomercurio-H2TMP did not alter NOS2 enzymatic activity, it blocked IFN-gamma-induced expression of NOS2 mRNA and protein, an effect that was enhanced in GSH-depleted cells. Iodomercurio-H2TMP was found to readily inhibit IFN-gamma signaling in transient transfection assays using NOS2 promoter/luciferase reporter constructs. NOS2 gene expression is known to require a variety of transcription factors including STAT-1, NF-kappaB and AP-1. Using mobility shift assays the psoralen, at concentrations that inhibit nitric oxide biosynthesis, had no effect on the DNA binding activity of STAT-1 or NF-kappaB. However, iodomercurio-H2TMP was found to suppress AP-1. These data indicate that iodomercurio-H2TMP acts at sulfhydryl-sensitive sites to inhibit NOS2. Moreover, this is dependent on early events in the IFN-gamma signal transduction pathway. Inhibition of AP-1 suggests that the psoralen functions by interfering with an important transcription factor that regulates expression of NOS2 in keratinocytes. PMID:16259964

  2. Balance between activating NKG2D, DNAM-1, NKp44 and NKp46 and inhibitory CD94/NKG2A receptors determine natural killer degranulation towards rheumatoid arthritis synovial fibroblasts

    PubMed Central

    Nielsen, Natasja; Pascal, Veronique; Fasth, Andreas E R; Sundström, Yvonne; Galsgaard, Elisabeth D; Ahern, David; Andersen, Martin; Baslund, Bo; Bartels, Else M; Bliddal, Henning; Feldmann, Marc; Malmström, Vivianne; Berg, Louise; Spee, Pieter; Söderström, Kalle

    2014-01-01

    Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation and synovial hyperplasia leading to progressive joint destruction. Fibroblast-like synoviocytes (FLS) are central components of the aggressive, tumour-like synovial structure termed pannus, which invades the joint space and cartilage. A distinct natural killer (NK) cell subset expressing the inhibitory CD94/NKG2A receptor is present in RA synovial fluid. Little is known about possible cellular interactions between RA-FLS and NK cells. We used cultured RA-FLS and the human NK cell line Nishi, of which the latter expresses an NK receptor repertoire similar to that of NK cells in RA synovial fluid, as an in vitro model system of RA-FLS/NK cell cross-talk. We show that RA-FLS express numerous ligands for both activating and inhibitory NK cell receptors, and stimulate degranulation of Nishi cells. We found that NKG2D, DNAM-1, NKp46 and NKp44 are the key activating receptors involved in Nishi cell degranulation towards RA-FLS. Moreover, blockade of the interaction between CD94/NKG2A and its ligand HLA-E expressed on RA-FLS further enhanced Nishi cell degranulation in co-culture with RA-FLS. Using cultured RA-FLS and the human NK cell line Nishi as an in vitro model system of RA-FLS/NK cell cross-talk, our results suggest that cell-mediated cytotoxicity of RA-FLS may be one mechanism by which NK cells influence local joint inflammation in RA. PMID:24673109

  3. Inhibition of rat peritoneal mast cell exocytosis by frusemide: a study with different secretagogues.

    PubMed

    Stenton, G R; Lau, H Y

    1996-10-01

    It has been reported that the loop diuretic frusemide can prevent exercise induced asthma, and that this effect may be due to the inhibition of mast cells in the airway. By using various mast cell secretagogues which increase intracellular calcium via different routes, this study attempted to elucidate the mechanism of the mast cell stabilizing action of frusemide. As well as confirming that immunologically induced histamine release from rat peritoneal mast cells was dose dependently inhibited by frusemide (10(-3) - 10(-5) M), the present study has extended the observation to histamine release induced by compound 48/80. The inhibitory potency was however less in the case of compound 48/80 induced release. Frusemide induced inhibition by the two secretagogues was decreased by drug preincubation. In contrast, histamine release induced by ionophore A23187 and thapsigargin was not inhibited by frusemide. The prototype antiallergic compound disodium cromoglycate (DSCG) demonstrated a similar specificity pattern against the various secretagogues. Another loop diuretic, bumetanide, did not show the same results as frusemide on rat peritoneal mast cell degranulation. Hence it is concluded that frusemide does not inhibit immunological activation of mast cells via its diuretic Na+/K+/Cl- co-transporter capacity. Instead, it protects mast cells in a similar manner to DSCG. PMID:8912016

  4. Kalanchoe pinnata inhibits mast cell activation and prevents allergic airway disease.

    PubMed

    Cruz, E A; Reuter, S; Martin, H; Dehzad, N; Muzitano, M F; Costa, S S; Rossi-Bergmann, B; Buhl, R; Stassen, M; Taube, C

    2012-01-15

    Aqueous extract of Kalanchoe pinnata (Kp) have been found effective in models to reduce acute anaphylactic reactions. In the present study, we investigate the effect of Kp and the flavonoid quercetin (QE) and quercitrin (QI) on mast cell activation in vitro and in a model of allergic airway disease in vivo. Treatment with Kp and QE in vitro inhibited degranulation and cytokine production of bone marrow-derived mast cells following IgE/Fc?RI crosslinking, whereas treatment with QI had no effect. Similarly, in vivo treatment with Kp and QE decreased development of airway hyperresponsiveness, airway inflammation, goblet cell metaplasia and production of IL-5, IL-13 and TNF. In contrast, treatment with QI had no effect on these parameters. These findings demonstrate that treatment with Kp or QE is effective in treatment of allergic airway disease, providing new insights to the immunomodulatory functions of this plant. PMID:21802918

  5. Damnacanthal inhibits IgE receptor-mediated activation of mast cells.

    PubMed

    Garcia-Vilas, Javier A; Medina, Miguel A; Melo, Fabio R; Pejler, Gunnar; Garcia-Faroldi, Gianni

    2015-05-01

    Damnacanthal, an anthraquinone obtained from the noni fruit (Morinda citrifolia L.), has been described to possess anti-cancer and anti-inflammatory properties. Since mast cells are key players in various inflammatory conditions as well as in cancer, we considered the possibility that the biological actions of damnacanthal, at least partly, could be due to effects on mast cells. Many of the biological activities of mast cells are mediated by IgE receptor cross-linking, which results in degranulation with release of preformed granule mediators, as well as de novo synthesis and release of additional compounds. Here we show that damnacanthal has profound inhibitory activity on mast cell activation through this pathway. The release of the granule compounds beta-hexosaminidase and tryptase release was completely abrogated by damnacanthal at doses that were non-toxic to mast cells. In addition, damnacanthal inhibited activation-dependent pro-inflammatory gene induction, as well as cytokine/chemokine release in response to mast cell stimulation. The mechanism underlying damnacanthal inhibition was linked to impaired phosphorylation of Syk and Akt. Furthermore, damnacanthal inhibited mast cell activation in response to calcium ionophore A23187. Altogether, the data presented here demonstrate that damnacanthal inhibits mast cell activation induced by different stimuli and open a new window for the use of this compound as a mast cell stabilizer. PMID:25656801

  6. Inhibition of an Allergen-Antibody Reaction Related to Japanese Cedar Pollinosis Using DNA Aptamers Against the Cry j 2 Allergen.

    PubMed

    Ogihara, Kazumasa; Savory, Nasa; Abe, Koichi; Yoshida, Wataru; Arakawa, Mitsuru; Asahi, Masahiko; Kamohara, Seika; Ikebukuro, Kazunori

    2015-12-01

    Japanese cedar pollinosis is one of the most prevalent allergies in Japan. Reducing the allergen content of pollen plays a major role in the alleviation of allergy symptoms. Aptamers, oligonucleotides with an affinity for specific molecules, have great potential for reducing allergic activity. In this study, we report that the anti-Cry j 2 aptamers, CJ2-04 and CJ2-08, inhibited allergen-antibody reactions between Cry j 2, one of the major allergens in Japanese cedar pollen, and immunoglobulin E in serum collected from a patient with Japanese cedar pollinosis. In addition, the suppression of Ca(2+) mobilization in basophils, which is related to degranulation, was observed in samples preincubated with either of these DNA aptamers. This study indicates that anti-Cry j 2 aptamers may inhibit allergen-antibody reactions and suppress the induction of Japanese cedar pollinosis, possibly leading to a novel external defense against this and other types of allergens. PMID:26484654

  7. Neutrophil migration towards C5a and CXCL8 is prevented by non-steroidal anti-inflammatory drugs via inhibition of different pathways

    PubMed Central

    Bertolotto, Maria; Contini, Paola; Ottonello, Luciano; Pende, Aldo; Dallegri, Franco; Montecucco, Fabrizio

    2014-01-01

    BACKGROUND AND PURPOSE Non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to induce PG-independent anti-inflammatory actions. Here, we investigated the role of three different NSAIDs (naproxen, ibuprofen and oxaprozin) on neutrophil responses to CXCL8 and C5a. EXPERIMENTAL APPROACH Human neutrophils were isolated from healthy volunteers by dextran and Ficoll-Hypaque density gradients. Neutrophils were pre-incubated with different concentrations (1–100 µM) of NSAIDs or kinase inhibitors. Neutrophil degranulation into supernatants was tested by elisa and zymography. Neutrophil chemotaxis was determined using Boyden chambers. F-actin polymerization was determined by Alexa-Fluor 488-conjugated phalloidin fluorescent assay. Integrin expression was assessed by flow cytometry. The phosphorylation of intracellular kinases was studied by Western blot. KEY RESULTS Pretreatment with NSAIDs did not affect neutrophil degranulation, but inhibited neutrophil migration and polymerization of F-actin, in response to CXCL8 and C5a. Pretreatment with different NSAIDs prevented C5a-induced integrin (CD11b) up-regulation, while only ibuprofen reduced CXCL8-induced CD11b up-regulation. Pre-incubation with naproxen or oxaprozin, but not ibuprofen, inhibited the PI3K/Akt-dependent chemotactic pathways. Both endogenous (released in cell supernatants) or exogenous (added to cell cultures) PGE2 did not affect C5a- or CXCL8-induced activities. Short-term incubation with NSAIDs did not affect neutrophil PGE2 release. CONCLUSION AND IMPLICATIONS Treatment with NSAIDs reduced C5a- and CXCL8-induced neutrophil migration and F-actin polymerization via different mechanisms. Inhibition by ibuprofen was associated with integrin down-regulation, while naproxen and oxaprozin blocked the PI3K/Akt pathway. Both NSAID actions were independent of COX inhibition and PGE2 release. PMID:24597536

  8. Mechanisms of growth inhibition in keratinocytes by mercurio-substituted 4',5'-dihydropsoralens.

    PubMed

    Martey, Christine A; Vetrano, Anna M; Whittemore, Marilyn S; Mariano, Thomas M; Gentile, Shannon L; Heck, Diane E; Laskin, Debra L; Heindel, Ned D; Laskin, Jeffrey D

    2002-06-01

    Psoralens, together with ultraviolet light A (PUVA), are used in the treatment of epidermal proliferative disorders. Although these compounds can enter cells and photo cross-link DNA, lipids and proteins, including a specific membrane receptor, are also potential targets for the psoralens. To better elucidate the site of action of the psoralens, we have synthesized a family of 5'-mercurio-substituted derivatives of 4',5'-dihydropsoralen. These compounds are identified by their heavy metal content and can be used as a model to deliver thiol reactive psoralen derivatives into keratinocytes. The 5'-mercuriopsoralen derivatives were found to be effective inhibitors of keratinocyte growth without photoactivation. The most active compound, 4,8-dimethyl-5'-iodomercuriomethyl-4',5'-dihydropsoralen (IC50=10 microM), was also a potent photosensitizer (IC50=0.3 microM). Depletion of keratinocyte GSH with buthionine sulfoximine markedly increased their sensitivity to this analog, both with and without UVA light. In contrast, N-acetyl-L-cysteine partially protected the cells from growth inhibition, indicating that a sulfhydryl-sensitive site is growth limiting and that this target can be photoactivated. Iodomercurio-4',5'-dihydropsoralen was found to form adducts with GSH and cysteine, which were not active without UVA light. Thus, these adducts may also contribute to the photosensitization reactions of the parent compound. Using plasmid DNA unwinding assays, iodomercurio-4',5'-dihydropsoralen was also found to modify DNA, an activity that increased following UVA light treatment. This suggests that DNA damage may contribute to the actions of these psoralens. Taken together, our data demonstrate that there are multiple sites of action for mercuriopsoralens. These compounds may prove useful for understanding the mechanisms of psoralen-induced growth inhibition in the skin. PMID:12093477

  9. Inhibition of human sPLA2 and 5-lipoxygenase activities by two neo-clerodane diterpenoids.

    PubMed

    Benrezzouk, R; Terencio, M C; Ferrándiz, M L; San Feliciano, A; Gordaliza, M; Miguel del Corral, J M; de la Puente, M L; Alcaraz, M J

    1999-01-01

    The inhibitory effect of two neo-clerodane diterpenoids, E-isolinaridial (EI) and its methylketone derivative (EIM), isolated from Linaria saxatilis var. glutinosa, on PLA2 and other enzyme activities involved in the inflammatory process was studied. Both compounds inhibited human synovial sPLA2 in a concentration-dependent manner with IC50 values of 0.20 and 0.49 microM, respectively, similar to scalaradial. Besides, these compounds decreased the cell-free 5-lipoxygenase activity and A23187-induced neutrophil LTB4 biosynthesis. Another function of human neutrophils, such as receptor-mediated degranulation, was also significantly reduced. In contrast, none of the compounds affected superoxide generation in leukocytes, or cyclooxygenase-1, cyclooxygenase-2 and inducible nitric oxide synthase activities in cell-free assays. PMID:10353635

  10. Piperine inhibits type II phosphatidylinositol 4-kinases: a key component in phosphoinositides turnover.

    PubMed

    Bojjireddy, Naveen; Sinha, Ranjeet Kumar; Subrahmanyam, Gosukonda

    2014-08-01

    Piperine has been shown to have anti-inflammatory properties. The molecular mechanisms by which it mediates anti-inflammatory activities remain elusive. Type II phosphatidylinositol 4-kinase(s) are key components in Fc?RI receptor-mediated signaling leading to inflammatory mediators release in RBL-2H3 cells. The effects of piperine on IgE-mediated signaling and mast cell degranulation were investigated. Pretreatment of RBL-2H3 cells with piperine inhibited IgE-induced activation of type II PtdIns 4-kinase(s). In vitro lipid kinase assays showed piperine-inhibited type II PtdIns 4-kinase activity in a dose-dependent fashion with no effect on PtdIns 3-kinase activity. Concomitantly, pretreatment of RBL-2H3 cells with piperine also inhibited IgE-induced ?-hexosaminidase release in RBL-2H3 cells. These results suggest that type II PtdIns 4-kinases are part of piperine-mediated anti-inflammatory signaling mechanisms. PMID:24671493

  11. Cheonggukjang Ethanol Extracts Inhibit a Murine Allergic Asthma via Suppression of Mast Cell-Dependent Anaphylactic Reactions

    PubMed Central

    Bae, Min-Jung; Shin, Hee Soon; See, Hye-Jeong

    2014-01-01

    Abstract Cheonggukjang (CGJ), a traditional Korean fermented soybean food, exerts immunomodulatory effects. Asthma is the most common chronic allergic disease to be associated with immune response to environmental allergens. In the pathogenesis of asthma, histamine is one of the important inflammatory mediators released from granules of mast cells. In this study, we evaluated the therapeutic effect of CGJ on a mouse model of ovalbumin (OVA)-induced asthma via the suppression of histamine release. C57BL/6 mice were sensitized by intraperitoneal injection of OVA or a phosphate-buffered saline (PBS) control and then challenged with OVA inhalation. Mice were treated intraperitoneally with either 70% ethanol-extracted CGJ (CGJE) (100?mg/kg/day) or equivalent PBS. Asthma-related inflammation was assessed by bronchoalveolar lavage fluid cell counts and histopathological and immunohistochemical analysis of lung tissues. To elucidate the mechanisms of asthma inhibition by CGJE treatment, we also examined degranulation and histamine release of compound 48/80-induced rat peritoneal mast cells (RPMCs). Treatment with CGJE downregulated the number of eosinophils and monocytes in the lungs of mice challenged with OVA and suppressed histopathological changes, such as eosinophil infiltration, mucus accumulation, goblet cell hyperplasia, and collagen fiber deposits. Moreover, CGJE alleviated compound 48/80-induced mast cell degranulation and histamine release from RPMCs through inhibition of calcium (Ca2+) uptake as well as ear swelling by infiltration of inflammatory cells. These findings demonstrated that CGJE can be used as an antiasthmatic dietary supplements candidate for histamine-mediated asthma. PMID:24456365

  12. Occupancy of adenosine receptors raises cyclic AMP alone and in synergy with occupancy of chemoattractant receptors and inhibits membrane depolarization.

    PubMed Central

    Cronstein, B N; Kramer, S B; Rosenstein, E D; Korchak, H M; Weissmann, G; Hirschhorn, R

    1988-01-01

    We have recently demonstrated that adenosine, acting via adenosine A2 receptors, inhibits generation of superoxide anions (O2-) by stimulated neutrophils. To determine the mechanism(s) by which adenosine inhibits O2- generation stimulated by the chemoattractant N-formylmethionylleucylphenylalanine (FMLP), we examined cyclic AMP (cAMP) concentrations, stimulated membrane depolarization and Ca2+ movements. Neither adenosine nor 5'-N-ethylcarboxamidoadenosine (NECA), the most potent agonist at adenosine A2 receptors, increases neutrophil cAMP content. However in the presence of the non-methylxanthine phosphodiesterase inhibitor, Ro-20-1724, both adenosine and NECA elicit a reversible increase in intracellular cAMP concentration. The chemoattractant FMLP also elicits an increment in the neutrophil cAMP content. NECA, in the presence of Ro-20-1724, synergistically enhances the increment in cAMP following stimulation by FMLP. However Ro-20-1724 does not potentiate the inhibition of O2- generation by NECA. Unlike other agents which increase neutrophil cAMP concentrations, NECA, even in the presence of a phosphodiesterase inhibitor, only trivially inhibits degranulation. We also found that adenosine markedly inhibits stimulated membrane depolarization but does not affect the stimulated increment in free ionized intracellular calcium. Moreover, inhibition by adenosine of O2- generation does not vary with the concentration of extracellular calcium. These results fulfil the last criterion for the demonstration of an A2 receptor on human neutrophils, and indicate that adenosine occupies an A2 receptor on neutrophils to raise intracellular cAMP in synergy with occupancy of the FMLP receptor. The results reported here also indicate that cAMP is not the second messenger for inhibition of O2- generation by adenosine and its analogues. PMID:2844154

  13. Nobiletin and tangeretin ameliorate scratching behavior in mice by inhibiting the action of histamine and the activation of NF-?B, AP-1 and p38.

    PubMed

    Jang, Se-Eun; Ryu, Kwon-Ryeol; Park, Sung-Hwan; Chung, Suna; Teruya, Yuto; Han, Myung Joo; Woo, Je-Tae; Kim, Dong-Hyun

    2013-11-01

    Nobiletin and tangeretin are polymethoxy flavonoids that are abundantly present in the pericarp of Citrus unshiu (family Rutaceae) and the fruit of Citrus depressa (family Rutaceae). They exhibit various biological activities, including anti-inflammatory and anti-asthmatic effects. To evaluate the anti-allergic effects of nobiletin and tangeretin, we measured their inhibitory effects in histamine- or compound 48/80-induced scratching behavioral mice. Nobiletin and tangeretin potently inhibited scratching behavior, as well as histamine-induced vascular permeability. Furthermore, they inhibited the expression of the allergic cytokines, IL-4 and TNF-? as well as the activation of their transcription factors NF-?B, AP-1 and p38 in histamine-stimulated skin tissues. They also inhibited the expression of IL-4 and TNF-? and the activation of NF-?B and c-jun in PMA-stimulated RBL-2H3 cells. Furthermore, nobiletin and tangeretin inhibited protein kinase C (PKC) activity and the IgE-induced degranulation of RBL-2H3 cells. These agents showed potent anti-histamine effect through the Magnus test when guinea pig ileum was used. Based on these results, nobiletin and tangeretin may ameliorate scratching behavioral reactions by inhibiting the action of histamine as well as the activation of the transcription factors NF-?B and AP-1 via PKC. PMID:23938254

  14. Monomethyl fumarate augments NK cell lysis of tumor cells through degranulation and the upregulation of NKp46 and CD107a.

    PubMed

    Vego, Heidi; Sand, Kristin L; Høglund, Rune A; Fallang, Lars-Egil; Gundersen, Glenn; Holmøy, Trygve; Maghazachi, Azzam A

    2016-01-01

    Dimethyl fumarate (DMF) is a new drug used to treat multiple sclerosis (MS) patients. Here, we examined the effects of DMF and the DMF metabolite monomethyl fumarate (MMF) on various activities of natural killer (NK) cells. We demonstrated that MMF augments the primary CD56(+), but not CD56(-), NK cell lysis of K562 and RAJI tumor cells. MMF induced NKp46 expression on the surface of CD56(+), but not CD56(-), NK cells after incubation for 24 h. This effect was closely correlated with the upregulation of CD107a expression on the surface of CD56(+) NK cells and the induction of Granzyme B release from these cells through this metabolite. An anti-NKp46 antibody inhibited the MMF-induced upregulation of CD107a and the lysis of tumor cells through CD56(+) NK cells. Thus, these results are the first to show that MMF augments CD56(+) NK cell lysis of tumor target cells, an effect mediated through NKp46. This novel effect suggests the use of MMF for therapeutic and/or preventive protocols in cancer. PMID:25435072

  15. Charybdotoxin is a new member of the K sup + channel toxin family that includes dendrotoxin I and mast cell degranulating peptide

    SciTech Connect

    Schweitz, H.; Bidard, J.N.; Lazdunski, M. ); Maes, P. )

    1989-12-12

    A polypeptide was identified in the venom of the scorpion Leiurus quinquestriatus hebraeus by its potency to inhibit the high affinity binding of the radiolabeled snake venom toxin dendrotoxin I ({sup 125}I-DTX{sub I}) to its receptor site. It has been purified, and its properties investigated by different techniques were found to be similar to those of MCD and DTX{sub I}, two polypeptide toxins active on a voltage-dependent K{sup +} channel. However, its amino acid sequence was determined, and it was shown that this toxin is in fact charybdotoxin (ChTX), a toxin classically used as a specific tool to block one class of Ca{sup 2+}-activated K{sup +} channels. ChTX, DTX{sub I}, and MCD are potent convulsants and are highly toxic when injected intracerebroventricularly in mice. Their toxicities correlate well with their affinities for their receptors in rat brain. These three structurally different toxins release ({sup 3}H)GABA from preloaded synaptosomes, the efficiency order being DTX{sub I} > ChTX > MCD. Both binding and cross-linking experiments of ChTX to rat brain membranes and to the purified MCD/DTX{sub I} binding protein have shown that the {alpha}-subunit of the MCD/DTX{sub I}-sensitive K{sup +} channel protein also contains the ChTX binding sites. Binding sites for DTX{sub I}, MCD, and ChTX are in negative allosteric interaction. The results show that charybdotoxin belongs to the family of toxins which already includes the dendrotoxins and MCD, which are blockers of voltage-sensitive K{sup +} channels. ChTX is clearly not selective for Ca{sup 2+}-activated K{sup +} channel.

  16. Osthol attenuates neutrophilic oxidative stress and hemorrhagic shock-induced lung injury via inhibition of phosphodiesterase 4.

    PubMed

    Tsai, Yung-Fong; Yu, Huang-Ping; Chung, Pei-Jen; Leu, Yann-Lii; Kuo, Liang-Mou; Chen, Chun-Yu; Hwang, Tsong-Long

    2015-12-01

    Oxidative stress caused by neutrophils is an important pathogenic factor in trauma/hemorrhagic (T/H)-induced acute lung injury (ALI). Osthol, a natural coumarin found in traditional medicinal plants, has therapeutic potential in various diseases. However, the pharmacological effects of osthol in human neutrophils and its molecular mechanism of action remain elusive. In this study, our data showed that osthol potently inhibited the production of superoxide anion (O2(•-)) and reactive oxidants derived therefrom as well as expression of CD11b in N-formylmethionylleucylphenylalanine (FMLP)-activated human neutrophils. However, osthol inhibited neutrophil degranulation only slightly and it failed to inhibit the activity of subcellular NADPH oxidase. FMLP-induced phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) was inhibited by osthol. Notably, osthol increased the cAMP concentration and protein kinase A (PKA) activity in activated neutrophils. PKA inhibitors reversed the inhibitory effects of osthol, suggesting that these are mediated through cAMP/PKA-dependent inhibition of ERK and Akt activation. Furthermore, the activity of cAMP-specific phosphodiesterase (PDE) 4, but not PDE3 or PDE7, was significantly reduced by osthol. In addition, osthol reduced myeloperoxidase activity and pulmonary edema in rats subjected to T/H shock. In conclusion, our data suggest that osthol has effective anti-inflammatory activity in human neutrophils through the suppression of PDE4 and protects significantly against T/H shock-induced ALI in rats. Osthol may have potential for future clinical application as a novel adjunct therapy to treat lung inflammation caused by adverse circulatory conditions. PMID:26432981

  17. Activated protein C inhibits neutrophil migration in allergic asthma: a randomised trial.

    PubMed

    de Boer, J Daan; Berger, Marieke; Majoor, Christof J; Kager, Liesbeth M; Meijers, Joost C M; Terpstra, Sanne; Nieuwland, Rienk; Boing, Anita N; Lutter, René; Wouters, Diana; Mierlo, Gerard J van; Zeerleder, Sacha S; Bel, Elisabeth H; Veer, Cornelis Van't; Vos, Alex F de; Zee, Jaring S van der; Poll, Tom van der

    2015-12-01

    Asthma patients show evidence of a procoagulant state in their airways, accompanied by an impaired function of the anticoagulant protein C system. We aimed to study the effect of recombinant human activated protein C (rhAPC) in allergic asthma patients.We conducted a randomised, double-blind, placebo-controlled, proof-of-concept study in house dust mite (HDM) allergic asthma patients. Patients were randomised to receive intravenous rhAPC (24?µg·kg(-1)·h(-1); n=12) or placebo (n=12) for 11?h. 4?h after the start of infusion, a first bronchoscopy was performed to challenge one lung segment with saline (control) and a contralateral segment with a combination of HDM extract and lipopolysaccharide (HDM+LPS), thereby mimicking environmental house dust exposure. A second bronchoscopy was conducted 8?h after intrabronchial challenge to obtain bronchoalveolar lavage fluid (BALF).rhAPC did not influence HDM+LPS induced procoagulant changes in the lung. In contrast, rhAPC reduced BALF leukocyte counts by 43% relative to placebo, caused by an inhibitory effect on neutrophil influx (64% reduction), while leaving eosinophil influx unaltered. rhAPC also reduced neutrophil degranulation products in the airways.Intravenous rhAPC attenuates HDM+LPS-induced neutrophil migration and protein release in allergic asthma patients by an effect that does not rely on coagulation inhibition. PMID:26381519

  18. Pentoxifylline inhibits Vgamma9/Vdelta2 T lymphocyte activation of patients with active Behçets disease in vitro.

    PubMed

    Accardo-Palumbo, A; Ferrante, A; Ciccia, F; Cadelo, M; Giardina, A R; Impastato, R; Triolo, G

    2007-01-01

    The aim of this study is to evaluate the in vitro effect of pentoxifylline (PTX) on T Vgamma9/Vdelta2 lymphocyte function in Behçets disease (BD). We investigated the effect of PTX on Vgamma9/Vdelta2 T cell expansion and expression of TNFRII receptor and perforin content before and after PTX addition by means of FACS analysis lymphocyte cultures from patients with active and inactive BD and healthy subjects. The addition of PTX at a concentration of 1 mg/ml determined a significant inhibition of cell expansion, a down regulation of TNF receptor expression and inhibited the PMA-induced degranulation of perforin. Taken together these data indicate that PTX is capable of interfering with Vgamma9/Vdelta2 T cell function in BD, and although cell culture models cannot reliably predict all of the potential effects of the drug in vivo, our results encourage the possibility that this drug may find use in a range of immunological disorder characterized by dysregulated cell-mediated immunity. PMID:17880773

  19. Sevoflurane ameliorates intestinal ischemia-reperfusion-induced lung injury by inhibiting the synergistic action between mast cell activation and oxidative stress

    PubMed Central

    LUO, CHENFANG; YUAN, DONGDONG; ZHAO, WEICHENG; CHEN, HUIXIN; LUO, GANGJIAN; SU, GUANGJIE; HEI, ZIQING

    2015-01-01

    Preconditioning with sevoflurane (SEV) can protect against ischemia-reperfusion injury in several organs, however, the benefits of SEV against acute lung injury (ALI), induced by intestinal ischemia-reperfusion (IIR), and the underlying mechanisms remain to be elucidated. The present study was designed to investigate the effects of SEV preconditioning on IIR-mediated ALI and the associated mechanisms in a rat model. Female Sprague-Dawley rats treated with 2.3% SEV or apocynin (AP), an inhibitor of NADPH oxidase, were subjected to 75 min superior mesenteric artery occlusion followed by 2 h reperfusion in the presence or absence of the mast cell degranulator compound 48/80 (CP). SEV and AP were observed to downregulate the protein expression levels of p47phox and gp91phox in the lungs of normal rats. IIR resulted in severe lung injury, characterized by significant increases in pathological injury scores, lung wet/dry weight ratio, protein expression levels of p47phox, gp91phox and ICAM-1, the presence of hydrogen peroxide, malondydehyde and interleukin-6, and the activity of myeloperoxidase. In addition, significant reductions were observed in the expression of prosurfactant protein C, accompanied by an increase in MC degranulation, demonstrated by significant elevations in the number of mast cells, expression levels of tryptase and the concentration of ?-hexosaminidase. These changes were further augmented in the presence of CP. In addition, SEV and AP preconditioning significantly alleviated the above alterations induced by IIR alone or in combination with CP. These findings suggested that SEV and AP attenuated IIR-induced ALI by inhibiting NADPH oxidase and the synergistic action between oxidative stress and mast cell activation. PMID:25815524

  20. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O. (Rodeo, CA); Spevak, Wayne R. (Albany, CA); Dasgupta, Falguni (New Delhi, IN); Bertozzi, Carolyn (Albany, CA)

    1999-10-05

    This invention provides a system for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, this system can be used to palliate certain inflammatory and immunological conditions.

  1. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O. (Rodeo, CA); Spevak, Wayne R. (Albany, CA); Dasgupta, Falguni (New Delhi, IN); Bertozzi, Caroline (Albany, CA)

    2001-10-09

    This invention provides compositions for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, these composition scan be used to palliate certain inflammatory and immunological conditions.

  2. Inhibition of selectin binding

    DOEpatents

    Nagy, Jon O. (Rodeo, CA); Spevak, Wayne R. (Albany, CA); Dasgupta, Falguni (New Delhi, IN); Bertozzi, Caroline (Albany, CA)

    1999-01-01

    This invention provides compositions for inhibiting the binding between two cells, one expressing P- or L-selectin on the surface and the other expressing the corresponding ligand. A covalently crosslinked lipid composition is prepared having saccharides and acidic group on separate lipids. The composition is then interposed between the cells so as to inhibit binding. Inhibition can be achieved at an effective oligosaccharide concentration as low as 10.sup.6 fold below that of the free saccharide. Since selectins are involved in recruiting cells to sites of injury, these composition scan be used to palliate certain inflammatory and immunological conditions.

  3. AOP description: Acetylcholinesterase inhibition

    EPA Science Inventory

    This adverse outcome pathway (AOP) leverages existing knowledge in the open literature to describe the linkage between inhibition of acetylcholinesterase (AChE) and the subsequent mortality resulting from impacts at cholinergic receptors. The AOP takes a chemical category approa...

  4. Human renin inhibiting dipeptide.

    PubMed

    Toda, N; Miyazaki, M; Etoh, Y; Kubota, T; Iizuka, K

    1986-10-01

    KRI-1177, a dipeptide containing nor-statine inhibited renin activity in human and Japanese monkey plasma to a markedly greater extent than that in dog, rabbit and rat plasma. The systemic blood pressure of anesthetized monkeys was lowered by intravenous injections of this compound which also reduced plasma renin activity and concentration of angiotensins. KRI-1177 appears to selectively inhibit primate renin activity, thereby producing hypotension. PMID:3536533

  5. Uptake of donor lymphocytes treated with 8-methoxypsoralen and ultraviolet A light by recipient dendritic cells induces CD4{sup +}CD25{sup +}Foxp3{sup +} regulatory T cells and down-regulates cardiac allograft rejection

    SciTech Connect

    Zheng, De-Hua; Dou, Li-Ping; Wei, Yu-Xiang; Du, Guo-Sheng; Zou, Yi-Ping; Song, Ji-Yong; Zhu, Zhi-Dong; Cai, Ming; Qian, Ye-Yong; Shi, Bing-Yi

    2010-05-14

    Extracorporeal photopheresis (ECP) is an effective immunomodulatory therapy and has been demonstrated to be beneficial for graft-vs-host disease and solid-organ allograft rejection. ECP involves reinfusion of a patient's autologous peripheral blood leukocytes treated ex vivo with 8-methoxypsoralen and UVA light radiation (PUVA). Previous studies focused only on ECP treatment of recipient immune cells. Our study is the first to extend the target of ECP treatment to donor immune cells. The results of in vitro co-culture experiments demonstrate uptake of donor PUVA-treated splenic lymphocytes (PUVA-SPs) by recipient immature dendritic cells (DCs). Phagocytosis of donor PUVA-SPs does not stimulate phenotype maturation of recipient DCs. In the same co-culture system, donor PUVA-SPs enhanced production of interleukin-10 and interferon-{gamma} by recipient DCs and impaired the subsequent capability of recipient DCs to stimulate recipient naive T cells. Phagocytosis of donor PUVA-SP (PUVA-SP DCs) by recipient DCs shifted T-cell responses in favor of T helper 2 cells. Infusion of PUVA-SP DCs inhibited cardiac allograft rejection in an antigen-specific manner and induced CD4{sup +}CD25{sup high}Foxp3{sup +} regulatory T cells. In conclusion, PUVA-SP DCs simultaneously deliver the donor antigen and the regulatory signal to the transplant recipient, and thus can be used to develop a novel DC vaccine for negative immune regulation and immune tolerance induction.

  6. Modulation of neutrophil degranulation by hypoxia

    E-print Network

    Hoenderdos, Kim

    2015-02-03

    -formly-methionyl-leucyl-phenylalanine G-CSF Granulocyte colony stimulating factor GM-CSF Ganulocyte-macrophage colony-stimulating factor GPCR G-protein coupled receptors GTP Guanine triphosphate H2O2 Hydrogen peroxide HBSS Hanks balanced salt solution... membrane and interact with the membrane-associated cytochrome b558. The assembled NADPH oxidase complex then catalyses a sequence of reactions, culminating in the formation of hydrogen peroxide (H2O2). Catalysed by myeloperoxidase (MPO) from...

  7. Derivative of wheat germ agglutinin specifically inhibits formyl-peptide-induced polymorphonuclear leukocyte chemotaxis by blocking re-expression (or recycling) of receptors

    SciTech Connect

    Perez, H.D.; Elfman, F.; Lobo, E.; Sklar, L.; Chenoweth, D.; Hooper, C.

    1986-03-01

    The mechanism of action of a derivative of wheat germ agglutinin (WGA-D) which specifically and irreversibly inhibits N-formyl-methionyl-leucyl-phenylalanine (FMLP)-induced polymorphonuclear leukocyte (PMN) chemotaxis was examined. At a concentration that completely inhibited PMN chemotaxis, WGA-D had no effect on either the uptake or release of (/sup 3/H)-FMLP by PMN. Similarly, WGA-D did not affect either the short-term binding to, or internalization by, PMN of a fluoresceinated FMLP analog. WGA-D did interfere, however, with the re-expression (or recycling) of FMLP receptors by PMN that had been preincubated with 1 ..mu..M FMLP for 10 min at 4/sup 0/C. This effect was specific for WGA-D, because it was not observed when concanavalin A was used. Scatchard plot analysis of FMLP binding to PMN after receptor re-expression demonstrated that WGA-D-treated PMN had a significant diminution in the number of high affinity receptors. WGA-D-mediated inhibition of FMLP receptor re-expression was associated with inhibition of FMLP-induced PMN chemotaxis, but had no effect on either FMLP-induced PMN superoxide anion generation or degranulation. Studies using (/sup 12/%I)-WGA-D demonstrated that PMN did not internalize WGA-D spontaneously. The data indicate that WGA-D perhaps by binding to the FMLP receptor, inhibits FMLP-induced PMN chemotaxis by blocking the re-expression (or recycling) of a population of receptors required for continuous migration.

  8. Nitric oxide inhibition strategies

    PubMed Central

    Wong, Vivian (Wai Chong); Lerner, Ethan

    2015-01-01

    Nitric oxide is involved in many physiologic processes. There are efforts, described elsewhere in this volume, to deliver nitric oxide to tissues as a therapy. Nitric oxide also contributes to pathophysiologic processes. Inhibiting nitric oxide or its production can thus also be of therapeutic benefit. This article addresses such inhibitory strategies. PMID:26634146

  9. Feedback inhibition of nitrogenase.

    PubMed

    Gordon, J K; Shah, V K; Brill, W J

    1981-12-01

    No inhibition of nitrogenase activity by physiological levels of NH4+ or carbamyl phosphate was observed in extracts of Azotobacter vinelandii. All of the 15N2 reduced by cultures which received no NH4+ was found in the cells. By contrast, more than 95% of the 15N2 reduced by cultures which had been given NH4+ was found in the medium. Failure to examine the culture medium would lead to the erroneous conclusion that N2 fixation is inhibited by NH4+. Nitrogenase in a derepressed mutant strain of A. vinelandii was fully active in vivo in the presence of NH4+. The addition of NH4Cl to N2-fixing cultures resulted in no decrease in the N2-reducing activity of intact cells of Klebsiella pneumoniae or Clostridium pasteurianum and only a small (15%) decrease in A. vinelandii. Therefore, no significant inhibition of nitrogenase by NH4+ or metabolites derived from NH4+ exists in A. vinelandii, K. pneumoniae, or C. pasteurianum. PMID:7031035

  10. n-3 Polyunsaturated fatty acids inhibit Fc ? receptor I-mediated mast cell activation.

    PubMed

    Wang, Xiaofeng; Ma, David W L; Kang, Jing X; Kulka, Marianna

    2015-12-01

    In vivo models show that n-3 polyunsaturated fatty acids (PUFA) inhibit some of the processes associated with allergic inflammation but the direct effect of n-3 PUFA on mast cells, the major effector cells in allergy, is poorly understood. We sought to determine the effect and mechanism of n-3 PUFA on Fc ? receptor I (Fc?RI)-mediated signal transduction and mast cell activation. Bone marrow-derived mast cells (BMMC) were differentiated from bone marrow obtained from C57BL/6 wild-type (WT) and fat-1 transgenic mice. The fat-1 mice express fatty acid n-3 desaturase and produce endogenous n-3 PUFA. For comparison, exogenous n-3 PUFA were supplemented to WT BMMC and human mast cell (LAD2) cultures. Fat-1 BMMC released less ?-hexosaminidase (?-hex) and cysteinyl leukotrienes and produced less tumor necrosis factor and chemokine (C-C motif) ligand 2. n-3 PUFA supplementation reduced LAD2 and BMMC degranulation (?-hex release) following Fc?RI activation. Fat-1 BMMC expressed less constitutive Lyn and linker of activated T cells (LAT), and Fc?RI-mediated phosphorylation of Lyn, spleen tyrosine kinase and LAT were reduced in fat-1 BMMC. Although the expression of surface and whole cell Fc?RI was similar in WT and fat-1 BMMC, unstimulated fat-1 BMMC showed reduced Fc?RI localization to lipid rafts, and stimulation with antigen resulted in aberrant Fc?RI shuttling to the rafts. Our results show that n-3 PUFA suppress Fc?RI-mediated activation of mast cells, which results in reduced mediator release. This effect is associated with a decrease in LAT and Lyn expression as well as abnormal shuttling of Fc?RI to lipid rafts. PMID:26363927

  11. Immunization with Hypoallergens of Shrimp Allergen Tropomyosin Inhibits Shrimp Tropomyosin Specific IgE Reactivity

    PubMed Central

    Wai, Christine Y. Y.; Leung, Nicki Y. H.; Ho, Marco H. K.; Gershwin, Laurel J.; Shu, Shang An; Leung, Patrick S. C.; Chu, Ka Hou

    2014-01-01

    Designer proteins deprived of its IgE-binding reactivity are being sought as a regimen for allergen-specific immunotherapy. Although shrimp tropomyosin (Met e 1) has long been identified as the major shellfish allergen, no immunotherapy is currently available. In this study, we aim at identifying the Met e 1 IgE epitopes for construction of hypoallergens and to determine the IgE inhibitory capacity of the hypoallergens. IgE-binding epitopes were defined by three online computational models, ELISA and dot-blot using sera from shrimp allergy patients. Based on the epitope data, two hypoallergenic derivatives were constructed by site-directed mutagenesis (MEM49) and epitope deletion (MED171). Nine regions on Met e 1 were defined as the major IgE-binding epitopes. Both hypoallergens MEM49 and MED171 showed marked reduction in their in vitro reactivity towards IgE from shrimp allergy patients and Met e 1-sensitized mice, as well as considerable decrease in induction of mast cell degranulation as demonstrated in passive cutaneous anaphylaxis assay. Both hypoallergens were able to induce Met e 1-recognizing IgG antibodies in mice, specifically IgG2a antibodies, that strongly inhibited IgE from shrimp allergy subjects and Met e 1-sensitized mice from binding to Met e 1. These results indicate that the two designer hypoallergenic molecules MEM49 and MED171 exhibit desirable preclinical characteristics, including marked reduction in IgE reactivity and allergenicity, as well as ability to induce blocking IgG antibodies. This approach therefore offers promises for development of immunotherapeutic regimen for shrimp tropomyosin allergy. PMID:25365343

  12. 4-Chlorotetrazolo[1,5-a]quinoxaline inhibits activation of Syk kinase to suppress mast cells in vitro and mast cell-mediated passive cutaneous anaphylaxis in mice

    SciTech Connect

    Park, Kui Lea; Ko, Na Young; Lee, Jun Ho; Kim, Do Kyun; Kim, Hyuk Soon; Kim, A-Ram; Her, Erk; Kim, Bokyung; Kim, Hyung Sik; Moon, Eun-Yi; Kim, Young Mi; Kim, Hang-Rae; Choi, Wahn Soo

    2011-12-15

    4-Chlorotetrazolo[1,5-a]quinoxaline is a quinoxaline derivative. We aimed to study the effects of 4-chlorotetrazolo[1,5-a]quinoxaline on activation of mast cells in vitro and in mice. 4-Chlorotetrazolo[1,5-a]quinoxaline reversibly inhibited degranulation of mast cells in a dose-dependent manner, and also suppressed the expression and secretion of TNF-{alpha} and IL-4 in mast cells. Mechanistically, 4-chlorotetrazolo[1,5-a]quinoxaline inhibited activating phosphorylation of Syk and LAT, which are crucial for early Fc{epsilon}RI-mediated signaling events, as well as Akt and MAP kinases, which play essential roles in the production of various pro-inflammatory cytokines in mast cells. Notably, although 4-chlorotetrazolo[1,5-a]quinoxaline inhibited the activation of Fyn and Syk, minimal inhibition was observed in mast cells in the case of Lyn. Furthermore, consistent with its in vitro activity, 4-chlorotetrazolo[1,5-a]quinoxaline significantly suppressed mast cell-mediated passive cutaneous anaphylaxis in mice. In summary, the results from this study demonstrate that 4-chlorotetrazolo[1,5-a]quinoxaline shows an inhibitory effect on mast cells in vitro and in vivo, and that this is mediated by inhibiting the activation of Syk in mast cells. Therefore, 4-chlorotetrazolo[1,5-a]quinoxaline could be useful in the treatment of mast cell-mediated allergic diseases. -- Highlights: Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline is a quinoxaline derivative. Black-Right-Pointing-Pointer The effect of 4-chlorotetrazolo[1,5-a]quinoxaline on mast cells was investigated. Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline reversibly inhibited Syk activation. Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline could be useful for IgE-mediated allergy.

  13. Dietary Compound Kaempferol Inhibits Airway Thickening Induced by Allergic Reaction in a Bovine Serum Albumin-Induced Model of Asthma.

    PubMed

    Shin, Daekeun; Park, Sin-Hye; Choi, Yean-Jung; Kim, Yun-Ho; Antika, Lucia Dwi; Habibah, Nurina Umy; Kang, Min-Kyung; Kang, Young-Hee

    2015-01-01

    Asthma is characterized by aberrant airways including epithelial thickening, goblet cell hyperplasia, and smooth muscle hypertrophy within the airway wall. The current study examined whether kaempferol inhibited mast cell degranulation and prostaglandin (PG) release leading to the development of aberrant airways, using an in vitro model of dinitrophenylated bovine serum albumin (DNP-BSA)-sensitized rat basophilic leukemia (RBL-2H3) mast cells and an in vivo model of BSA-challenged asthmatic mice. Nontoxic kaempferol at 10-20 ?M suppressed ?-hexosaminidase release and cyclooxygenase 2 (COX2)-mediated production of prostaglandin D2 (PGD2) and prostaglandin F2? (PGF2?) in sensitized mast cells. Oral administration of ?20 mg/kg kaempferol blocked bovine serum albumin (BSA) inhalation-induced epithelial cell excrescence and smooth muscle hypertrophy by attenuating the induction of COX2 and the formation of PGD2 and PGF2?, together with reducing the anti-?-smooth muscle actin (?-SMA) expression in mouse airways. Kaempferol deterred the antigen-induced mast cell activation of cytosolic phospholipase A2 (cPLA2) responsive to protein kinase C? (PKC?) and extracellular signal-regulated kinase (ERK). Furthermore, the antigen-challenged activation of Syk-phospholipase C? (PLC?) pathway was dampened in kaempferol-supplemented mast cells. These results demonstrated that kaempferol inhibited airway wall thickening through disturbing Syk-PLC? signaling and PKC?-ERK-cPLA2-COX2 signaling in antigen-exposed mast cells. Thus, kaempferol may be a potent anti-allergic compound targeting allergic asthma typical of airway hyperplasia and hypertrophy. PMID:26694364

  14. Pharmacological Inhibition of FTO

    PubMed Central

    McMurray, Fiona; Demetriades, Marina; Aik, WeiShen; Merkestein, Myrte; Kramer, Holger; Andrew, Daniel S.; Scudamore, Cheryl L.; Hough, Tertius A.; Wells, Sara; Ashcroft, Frances M.; McDonough, Michael A.; Schofield, Christopher J.; Cox, Roger D.

    2015-01-01

    In 2007, a genome wide association study identified a SNP in intron one of the gene encoding human FTO that was associated with increased body mass index. Homozygous risk allele carriers are on average three kg heavier than those homozygous for the protective allele. FTO is a DNA/RNA demethylase, however, how this function affects body weight, if at all, is unknown. Here we aimed to pharmacologically inhibit FTO to examine the effect of its demethylase function in vitro and in vivo as a first step in evaluating the therapeutic potential of FTO. We showed that IOX3, a known inhibitor of the HIF prolyl hydroxylases, decreased protein expression of FTO (in C2C12 cells) and reduced maximal respiration rate in vitro. However, FTO protein levels were not significantly altered by treatment of mice with IOX3 at 60 mg/kg every two days. This treatment did not affect body weight, or RER, but did significantly reduce bone mineral density and content and alter adipose tissue distribution. Future compounds designed to selectively inhibit FTO’s demethylase activity could be therapeutically useful for the treatment of obesity. PMID:25830347

  15. Wortmannin blocks lipid and protein kinase activities associated with PI 3-kinase and inhibits a subset of responses induced by Fc epsilon R1 cross-linking.

    PubMed Central

    Barker, S A; Caldwell, K K; Hall, A; Martinez, A M; Pfeiffer, J R; Oliver, J M; Wilson, B S

    1995-01-01

    We have investigated the effects of wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI 3-kinase), on antigen-mediated signaling in the RBL-2H3 mast cell model. In RBL-2H3 cells, the cross-linking of high affinity IgE receptors (Fc epsilon R1) activates at least two cytoplasmic protein tyrosine kinases, Lyn and Syk, and stimulates secretion, membrane ruffling, spreading, pinocytosis, and the formation of actin plaques implicated in increased cell-substrate adhesion. In addition, Fc epsilon R1 cross-linking activates PI 3-kinase. It was previously shown that wortmannin causes a dose-dependent inhibition of PI 3-kinase activity and also inhibits antigen-stimulated degranulation. We report that the antigen-induced synthesis of inositol(1,4,5)P3 is also markedly inhibited by wortmannin. Consistent with evidence in other cell systems implicating phosphatidylinositol(3,4,5)P3 in ruffling, pretreatment of RBL-2H3 cells with wortmannin inhibits membrane ruffling and fluid pinocytosis in response to Fc epsilon R1 cross-linking. However, wortmannin does not inhibit antigen-induced actin polymerization, receptor internalization, or the actin-dependent processes of spreading and adhesion plaque formation that follow antigen stimulation in adherent cells. Wortmannin also fails to inhibit either of the Fc epsilon R1-coupled tyrosine kinases, Lyn or Syk, or the activation of mitogen-activated protein kinase as measured by in vitro kinase assays. Strikingly, there is substantial in vitro serine/threonine kinase activity in immunoprecipitates prepared from Fc epsilon R1-activated cells using antisera to the p85 subunit of PI 3-kinase. This activity is inhibited by pretreatment of the cells with wortmannin or by the direct addition of wortmannin to the kinase assay, suggesting that PI 3-kinase itself is capable of acting as a protein kinase. We conclude that Fc epsilon R1 cross-linking activates both lipid and protein kinase activities of PI 3-kinase and that inhibiting these activities with wortmannin results in the selective block of a subset of Fc epsilon R1-mediated signaling responses. Images PMID:8534912

  16. Method for decreasing radiation load in puva therapy

    SciTech Connect

    Wolff, K.

    1987-02-10

    An improved method is described for treating a psoriatic subject undergoing treatment with a psoralen in conjection with ultraviolet A radiation of from wavelength of 3200 to 4000 angstroms. The improved method comprises prior to initiation of the treatment, pretreating the subject for a period of from 4 to 10 days with an effective amount of an anti-psoriatic polyene compound, and thereafter initiating the treatment with a psoralen in conjunction with ultraviolet A radiation and continuing the treatment concurrently with the administration of the anti-psoriatic polyene compound.

  17. How Inhibition Shapes Cortical Activity

    PubMed Central

    Isaacson, Jeffery S.; Scanziani, Massimo

    2011-01-01

    Summary Cortical processing reflects the interplay of synaptic excitation and synaptic inhibition. Rapidly accumulating evidence is highlighting the crucial role of inhibition in shaping spontaneous and sensory-evoked cortical activity and thus underscores how a better knowledge of inhibitory circuits is necessary for our understanding of cortical function. We discuss current views of how inhibition regulates the function of cortical neurons and point to a number of important open questions. PMID:22017986

  18. Ethanol Inhibits High-Affinity Immunoglobulin E Receptor (Fc?RI) Signaling in Mast Cells by Suppressing the Function of Fc?RI-Cholesterol Signalosome

    PubMed Central

    Draberova, Lubica; Paulenda, Tomas; Halova, Ivana; Potuckova, Lucie; Bugajev, Viktor; Bambouskova, Monika; Tumova, Magda; Draber, Petr

    2015-01-01

    Ethanol has multiple effects on biochemical events in a variety of cell types, including the high-affinity immunoglobulin E receptor (Fc?RI) signaling in antigen-activated mast cells. However, the underlying molecular mechanism remains unknown. To get better understanding of the effect of ethanol on Fc?RI-mediated signaling we examined the effect of short-term treatment with non-toxic concentrations of ethanol on Fc?RI signaling events in mouse bone marrow-derived mast cells. We found that 15 min exposure to ethanol inhibited antigen-induced degranulation, calcium mobilization, expression of proinflammatory cytokine genes (tumor necrosis factor-?, interleukin-6, and interleukin-13), and formation of reactive oxygen species in a dose-dependent manner. Removal of cellular cholesterol with methyl-?-cyclodextrin had a similar effect and potentiated some of the inhibitory effects of ethanol. In contrast, exposure of the cells to cholesterol-saturated methyl-?-cyclodextrin abolished in part the inhibitory effect of ethanol on calcium response and production of reactive oxygen species, supporting lipid-centric theories of ethanol action on the earliest stages of mast cell signaling. Further studies showed that exposure to ethanol and/or removal of cholesterol inhibited early Fc?RI activation events, including tyrosine phosphorylation of the Fc?RI ? and ? subunits, SYK kinases, LAT adaptor protein, phospholipase C?, STAT5, and AKT and internalization of aggregated Fc?RI. Interestingly, ethanol alone, and particularly in combination with methyl-?-cyclodextrin, enhanced phosphorylation of negative regulatory tyrosine 507 of LYN kinase. Finally, we found that ethanol reduced passive cutaneous anaphylactic reaction in mice, suggesting that ethanol also inhibits Fc?RI signaling under in vivo conditions. The combined data indicate that ethanol interferes with early antigen-induced signaling events in mast cells by suppressing the function of Fc?RI-cholesterol signalosomes at the plasma membrane. PMID:26658290

  19. Fusion Peptides CPU1 and CPU2 Inhibit Matrix Metalloproteinases and Protect Mice from Endotoxin Shock Within a Strict Time Window.

    PubMed

    Qiu, Zheng; Zhang, Fengguo; Gong, Chengxin; Xu, Hanmei; Hu, Jialiang

    2015-12-01

    Endotoxin shock induction in mice is a commonly used animal model to evaluate the protective effect of biologically active reagents. After an lipopolysaccharides (LPS) stimulus, matrix metalloproteinase-8 (MMP-8) and matrix metalloproteinase-9 (MMP-9) are rapidly degranulated and released by neutrophils, aside other enzymes and effector molecules. MMPs cleave extracellular matrix components and cytokines, and such processes contribute to shock syndrome development. CPU1 and CPU2 are two peptide MMP inhibitors with different in vitro IC50 values to several key enzymes, including MMP-8 and MMP-9. In vivo work confirmed that CPU1 and CPU2 protected mice from endotoxin shock after intravenous and intraperitoneal injections. Furthermore, their minimal effective dose after an intravenous injection and the maximum time interval between intraperitoneal peptide injection (150 mg/kg) and intravenous LPS injection were determined. With the use of an indirect competitive ELISA, plasma CPU1 and CPU2 concentrations in different experimental settings were measured. In addition, the acuteness of MMP-9 release in the mouse circulation after an intravenous LPS injection was confirmed with the zymography technique. Our findings reinforce previous work with other inhibitors about a strict time window within which effective MMP inhibition is needed to obtain significant survival rate improvements and also show that, with strict pharmacokinetic monitoring, potent protease inhibitors may in the future become life-savers in shock conditions. PMID:26111477

  20. Cassia tora Seed Extract and Its Active Compound Aurantio-obtusin Inhibit Allergic Responses in IgE-Mediated Mast Cells and Anaphylactic Models.

    PubMed

    Kim, Myungsuk; Lim, Sue Ji; Lee, Hee-Ju; Nho, Chu Won

    2015-10-21

    Cassia tora seed is widely used due to its various biological properties including anticancer, antidiabetic, and anti-inflammatory effects. However, there has been no report of the effects of C. tora seed extract (CTE) on immunoglobulin E (IgE)-mediated allergic responses. In this research, we demonstrated the effects of CTE and its active compound aurantio-obtusin on IgE-sensitized allergic reactions in mast cells and passive cutaneous anaphylaxis (PCA). CTE and aurantio-obtusin suppressed degranulation, histamine production, and reactive oxygen species generation and inhibited the production and mRNA expression of tumor necrosis factor-? and interleukin-4. CTE and aurantio-obtusin also suppressed the prostaglandin E2 production and expression of cyclooxygenase 2. Furthermore, CTE and aurantio-obtusin suppressed IgE-mediated Fc?RI signaling such as phosphorylation of Syk, protein kinase C?, phospholipase C?, and extracellular signal-regulated kinases. CTE and aurantio-obtusin blocked mast cell-dependent PCA in IgE-mediated mice. These results suggest that CTE and aurantio-obtusin are a beneficial treatment for allergy-related diseases. PMID:26434611

  1. Propolis inhibits osteoclast maturation.

    PubMed

    Pileggi, Roberta; Antony, Kathryn; Johnson, Kristie; Zuo, Jian; Shannon Holliday, L

    2009-12-01

    Propolis, a natural product produced by the honey bee, has been successfully used in medicine as an anti-inflammatory and antimicrobial agent. Traumatic injuries to the teeth, especially avulsion injuries, present a challenging situation for the clinician because of post-treatment complications, such as inflammatory and/or replacement resorption. Agents that reduce osteoclast numbers and activity may be useful in the treatment of traumatic injuries to the teeth. In this study, we evaluated propolis as an anti-resorptive agent. Calcitriol-stimulated mouse marrow cultures, which contain both osteoclasts and osteoblasts, were exposed to the ethanol extracts of propolis or vehicle control and stained for tartrate-resistant acid phosphatase (TRAP)-activity to identify osteoclasts. A significant, dose-dependent reduction in multinuclear TRAP+ cells was demonstrated, although the propolis treatment accommodated cell growth and survival (P < 0.05). Propolis also reduced the formation of actin rings in pure cultures of RAW 264.7 osteoclast-like cells, suggesting that it exerts direct actions on osteoclast maturation. In summary, our data suggest that propolis inhibits late stages of osteoclast maturation including fusion of osteoclasts precursors to form giant cells and formation of actin rings. This supports the hypothesis that it may prove useful as a medicament to reduce resorption associated with traumatic injuries to the teeth. PMID:19843135

  2. Inhibition of MMPs by alcohols

    PubMed Central

    Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Hoshika, Tomohiro; Uchiyama, Toshikazu; Tjäderhane, Leo; Breschi, Lorenzo; Mazzoni, Annalisa; Thompson, Jeremy M.; McCracken, Courtney E.; Looney, Stephen W.; Tay, Franklin R.; Pashley, David H.

    2011-01-01

    Objectives While screening the activity of potential inhibitors of matrix metalloproteinases (MMPs), due to the limited water solubility of some of the compounds, they had to be solubilized in ethanol. When ethanol solvent controls were run, they were found to partially inhibit MMPs. Thus, the purpose of this study was to compare the MMP-inhibitory activity of a series of alcohols. Methods The possible inhibitory activity of a series of alcohols was measured against soluble rhMMP-9 and insoluble matrix-bound endogenous MMPs of dentin in completely demineralized dentin. Increasing concentrations (0.17, 0.86, 1.71 and 4.28 moles/L) of a homologous series of alcohols (i.e. methanol, ethanol, propanols, butanols, pentanols, hexanols, the ethanol ester of methacrylic acid, heptanols and octanol) were compared to ethanediol, and propanediol by regression analysis to calculate the molar concentration required to inhibit MMPs by 50% (i.e. the IC50). Results Using two different MMP models, alcohols were shown to inhibit rhMMP-9 and the endogenous proteases of dentin matrix in a dose-dependent manner. The degree of MMP inhibition by alcohols increased with chain length up to 4 methylene groups. Based on the molar concentration required to inhibit rhMMP-9 fifty percent, 2-hydroxyethylmethacrylate (HEMA), 3-hexanol, 3-heptanol and 1-octanol gave the strongest inhibition. Significance The results indicate that alcohols with 4 methylene groups inhibit MMPs more effectively than methanol or ethanol. MMP inhibition was inversely related to the Hoy's solubility parameter for hydrogen bonding forces of the alcohols (i.e. to their hydrophilicity). PMID:21676453

  3. Suppressive effects of Schizandra chinensis Baillon water extract on allergy-related cytokine generation and degranulation in IgE-antigen complex-stimulated RBL-2H3 cells

    PubMed Central

    Chung, Mi Ja; Kim, Jeong-Mi; Lee, Sangchul; Kim, Taewoo; Kim, Daejung; Baek, Jongmi; Kim, Taehyuk; Lee, Jaesung; Kim, Kyoungkon; Yoon, Jin A

    2012-01-01

    Schizandra chinensis Baillon is a traditional folk medicine plant that is used to treat and prevent several inflammatory diseases and cancer in Korea, but the underlying mechanisms involved in its anti-allergic activity are not fully understood. This study was designed to investigate mechanisms of anti-allergic activity of a Schizandra chinensis Baillon water extract (SCWE) in immunoglobulin E (IgE)-antigen complex-stimulated RBL2H3 cells and to assess whether gastric and intestinal digestion affects the anti-allergic properties of SCWE. Oxidative stress is an important consequence of the allergic inflammatory response. The antioxidant activities of SCWE increased in a concentration-dependent manner. RBL-2H3 cells were sensitized with monoclonal anti-dinitrophenol (DNP) specific IgE, treated with SCWE, and challenged with the antigen DNP-human serum albumin. SCWE inhibited ?-hexosaminidase release and expression of interleukin (IL)-4, IL-13, and tumor necrosis factor-alpha (TNF-?) mRNA and protein in IgE-antigen complex-stimulated RBL2H3 cells. We found that digested SCWE fully maintained its antioxidant activity and anti-allergic activity against the IgE-antigen complex-induced activation of RBL-2H3 cells. SCWE may be useful for preventing allergic diseases, such as asthma. Thus, SCWE could be used as a natural functional ingredient for allergic diseases in the food and/or pharmaceutical industries. PMID:22586497

  4. Remote inhibition of polymer degradation.

    SciTech Connect

    Clough, Roger Lee; Celina, Mathias Christopher

    2005-08-01

    Polymer degradation has been explored on the basis of synergistic infectious and inhibitive interaction between separate materials. A dual stage chemiluminescence detection system with individually controlled hot stages was applied to probe for interaction effects during polymer degradation in an oxidizing environment. Experimental confirmation was obtained that volatile antioxidants can be transferred over a relatively large distance. The thermal degradation of a polypropylene (PP) sample receiving traces of inhibitive antioxidants from a remote source is delayed. Similarly, volatiles from two stabilized elastomers were also capable of retarding a degradation process remotely. This observation demonstrates inhibitive cross-talk as a novel interactive phenomenon between different polymers and is consequential for understanding general polymer interactions, fundamental degradation processes and long-term aging effects of multiple materials in a single environment.

  5. Post-Stop-Signal Adjustments: Inhibition Improves Subsequent Inhibition

    ERIC Educational Resources Information Center

    Bissett, Patrick G.; Logan, Gordon D.

    2012-01-01

    Performance in the stop-signal paradigm involves a balance between going and stopping, and one way that this balance is struck is through shifting priority away from the go task, slowing responses after a stop signal, and improving the probability of inhibition. In 6 experiments, the authors tested whether there is a corresponding shift in…

  6. Action spectra for photosynthetic inhibition

    NASA Technical Reports Server (NTRS)

    Caldwell, M. M.; Flint, S.; Camp, L. B.

    1981-01-01

    The ultraviolet action spectrum for photosynthesis inhibition was determined to fall between that of the general DNA action spectrum and the generalized plant action spectrum. The characteristics of this action spectrum suggest that a combination of pronounced increase in effectiveness with decreasing wavelength, substantial specificity for the UV-B waveband, and very diminished response in the UV-A waveband result in large radiation amplification factors when the action spectra are used as weighting functions. Attempted determination of dose/response relationships for leaf disc inhibition provided inconclusive data from which to deconvolute an action spectrum.

  7. Subliminal priming of intentional inhibition.

    PubMed

    Parkinson, Jim; Haggard, Patrick

    2014-02-01

    Intentional choice is an important process underlying human behaviour. Intentional inhibition refers to the capacity to endogenously cancel an about-to-be-executed action at the last moment. Previous research suggested that such intentional inhibitory control requires conscious effort and awareness. Here we show that intentional decisions to inhibit are nevertheless influenced by unconscious processing. In a novel version of the Go/No-Go task, participants made speeded keypress actions to a Go target, or withheld responses to a No-Go target, or made free, spontaneous choices whether to execute or inhibit a keypress when presented with a free-choice target. Prior to each target, subliminal masked prime arrows were presented. Primes could be congruent with the Go or No-Go arrows, or neutral. Response times and proportion of action choices were measured. Primes were presented at latencies that would give either positive or negative compatibility effects (PCE, Experiment 1, and NCE, Experiment 2, respectively), based on previous literature. Go-primes at positive-compatibility latencies facilitated speeded response times as expected, but did not influence number of choices to act on free-choice trials. However, when Go primes were presented at negative-compatibility latencies, "free" decisions to inhibit were significantly increased. Decisions to act or not can be unconsciously manipulated, at least by inhibitory mechanisms. The cognitive mechanisms for intentionally withholding an action can be influenced by unconscious processing. We discuss possible moral and legal implications of these findings. PMID:24334316

  8. Infant Predictors of Behavioural Inhibition

    ERIC Educational Resources Information Center

    Moehler, Eva; Kagan, Jerome; Oelkers-Ax, Rieke; Brunner, Romuald; Poustka, Luise; Haffner, Johann; Resch, Franz

    2008-01-01

    Behavioural inhibition in the second year of life is a hypothesized predictor for shyness, social anxiety and depression in later childhood, adolescence and even adulthood. To search for the earliest indicators of this fundamental temperamental trait, this study examined whether behavioural characteristics in early infancy can predict behavioural…

  9. Islam Does Not Inhibit Science.

    ERIC Educational Resources Information Center

    Shanavas, T. O.

    1999-01-01

    Compares the science/religion relationship in both Christian and Islamic countries. Presents Muslim scholars' ideas about the presence of humans on earth. Presents ideas on active nature, Noah's curse, and the age of the universe. Refutes the notion that Islam inhibited science and advocates the belief that Islam promoted science. (YDS)

  10. Inhibition in Prolonged Work Tasks.

    ERIC Educational Resources Information Center

    van der Ven, A. H. G. S.; And Others

    1989-01-01

    A new model is presented that explains reaction time fluctuations in prolonged work tasks. The model extends the so-called Poisson-Erlang model and accounts for long-term trend effects in the reaction time curve. The model is consistent with Spearman's hypothesis that inhibition increases during work and decreases during rest. (TJH)

  11. Inhibition of Hsp90 in Streptomyces coelicolor

    E-print Network

    Wu, Katherine A. (Katherine Ann)

    2005-01-01

    Inhibition of the chaperone protein Hsp90 in plants and insects has been found to result in drastic changes in phenotype. We investigated the effect of Hsp90 inhibition on the bacteria Streptomyces coelicolor. These changes ...

  12. Threat interferes with response inhibition.

    PubMed

    Hartikainen, Kaisa M; Siiskonen, Anna R; Ogawa, Keith H

    2012-05-01

    A potential threat, such as a spider, captures attention and engages executive functions to adjust ongoing behavior and avoid danger. We and many others have reported slowed responses to neutral targets in the context of emotional distractors. This behavioral slowing has been explained in the framework of attentional competition for limited resources with emotional stimuli prioritized. Alternatively, slowed performance could reflect the activation of avoidance/freezing-type motor behaviors associated with threat. Although the interaction of attention and emotion has been widely studied, little is known on the interaction between emotion and executive functions. We studied how threat-related stimuli (spiders) interact with executive performance and whether the interaction profile fits with a resource competition model or avoidance/freezing-type motor behaviors. Twenty-one young healthy individuals performed a Go-NoGo visual discrimination reaction time (RT) task engaging several executive functions with threat-related and emotionally neutral distractors. The threat-related distractors had no effect on the RT or the error rate in the Go trials. The NoGo error rate, reflecting failure in response inhibition, increased significantly because of threat-related distractors in contrast to neutral distractors, P less than 0.05. Thus, threat-related distractors temporarily impaired response inhibition. Threat-related distractors associated with increased commission errors and no effect on RT does not suggest engagement of avoidance/freezing-type motor behaviors. The results fit in the framework of the resource competition model. A potential threat calls for evaluation of affective significance as well as inhibition of undue emotional reactivity. We suggest that these functions tax executive resources and may render other executive functions, such as response inhibition, temporarily compromised when the demands for resources exceed availability. PMID:22494999

  13. RAAS inhibition and cardiorenal syndrome.

    PubMed

    Onuigbo, Macaulay Amechi C

    2014-01-01

    The consensus conference on cardio-renal syndromes (2008) defined 'cardio-renal syndromes' as 'disorders of the heart and kidneys whereby acute or chronic dysfunction in one organ may induce acute or chronic dysfunction of the other' and identified five subtypes of the syndromes. Various pathophysiologic mechanisms underlie cardiorenal syndrome including hemodynamic derangements, reduced cardiac output leading to impaired renal perfusion, reduced stroke volume, raised atrial filling pressures, elevated atrial pressures, sodium and water retention, venous congestion, right ventricular dysfunction and venous hypertension causing increased renal venous pressure, intra-abdominal hypertension, various neurohormonal adaptations including activation of the renin-angiotensin-aldosterone system, adaptive activation of the sympathetic nervous system, cytokine release and oxidative stress. Although there are standardized clinical guidelines for the management of heart failure, and chronic kidney disease, respectively, there are no similar consensus clinical guidelines for the management of the cardiorenal syndromes. RAAS inhibition is advocated in treating systolic heart failure. There is evidence that RAAS inhibition is also useful in cardiorenal syndrome. However, RAAS inhibition, while potentially useful in the management of cardiorenal syndrome, is not the 'magic bullet', is sometimes limited by adverse renal events, is not applicable to all patients, and must be applied by physicians with due diligence and caution. Nevertheless, a more comprehensive multidisciplinary multipronged approach to managing patients with cardiorenal syndrome is even more pragmatic and commonsense given the multiple mechanisms and pathogenetic pathways implicated in the causation and perpetuation of cardiorenal syndrome. PMID:25549841

  14. Honokiol inhibits lung tumorigenesis through inhibition of mitochondrial function.

    PubMed

    Pan, Jing; Zhang, Qi; Liu, Qian; Komas, Steven M; Kalyanaraman, Balaraman; Lubet, Ronald A; Wang, Yian; You, Ming

    2014-11-01

    Honokiol is an important bioactive compound found in the bark of Magnolia tree. It is a nonadipogenic PPAR? agonist and capable of inhibiting the growth of a variety of tumor types both in vitro and in xenograft models. However, to fully appreciate the potential chemopreventive activity of honokiol, a less artificial model system is required. To that end, this study examined the chemopreventive efficacy of honokiol in an initiation model of lung squamous cell carcinoma (SCC). This model system uses the carcinogen N-nitroso-trischloroethylurea (NTCU), which is applied topically, reliably triggering the development of SCC within 24 to 26 weeks. Administration of honokiol significantly reduced the percentage of bronchial that exhibit abnormal lung SCC histology from 24.4% bronchial in control to 11.0% bronchial in honokiol-treated group (P = 0.01) while protecting normal bronchial histology (present in 20.5% of bronchial in control group and 38.5% of bronchial in honokiol-treated group. P = 0.004). P63 staining at the SCC site confirmed the lung SCCs phenotype. In vitro studies revealed that honokiol inhibited lung SCC cells proliferation, arrested cells at the G1-S cell-cycle checkpoint, while also leading to increased apoptosis. Our study showed that interfering with mitochondrial respiration is a novel mechanism by which honokiol changed redox status in the mitochondria, triggered apoptosis, and finally leads to the inhibition of lung SCC. This novel mechanism of targeting mitochondrial suggests honokiol as a potential lung SCC chemopreventive agent. PMID:25245764

  15. Self-regulation, ego depletion, and inhibition.

    PubMed

    Baumeister, Roy F

    2014-12-01

    Inhibition is a major form of self-regulation. As such, it depends on self-awareness and comparing oneself to standards and is also susceptible to fluctuations in willpower resources. Ego depletion is the state of reduced willpower caused by prior exertion of self-control. Ego depletion undermines inhibition both because restraints are weaker and because urges are felt more intensely than usual. Conscious inhibition of desires is a pervasive feature of everyday life and may be a requirement of life in civilized, cultural society, and in that sense it goes to the evolved core of human nature. Intentional inhibition not only restrains antisocial impulses but can also facilitate optimal performance, such as during test taking. Self-regulation and ego depletion- may also affect less intentional forms of inhibition, even chronic tendencies to inhibit. Broadly stated, inhibition is necessary for human social life and nearly all societies encourage and enforce it. PMID:25149821

  16. Kinetics and Inhibition of Reductive Dechlorination of Chlorinated

    E-print Network

    Semprini, Lewis

    Kinetics and Inhibition of Reductive Dechlorination of Chlorinated Ethylenes by Two Different Mixed inhibition between chlorinated ethylenes. The more chlorinated ethylenes inhibited the reductive dechlorination of the less chlorinated ethylenes, while the less chlorinated ethylenes weakly inhibited

  17. Interferon-? Inhibits Ebola Virus Infection

    PubMed Central

    Rhein, Bethany A.; Powers, Linda S.; Rogers, Kai; Anantpadma, Manu; Singh, Brajesh K.; Sakurai, Yasuteru; Bair, Thomas; Miller-Hunt, Catherine; Sinn, Patrick; Davey, Robert A.

    2015-01-01

    Ebola virus outbreaks, such as the 2014 Makona epidemic in West Africa, are episodic and deadly. Filovirus antivirals are currently not clinically available. Our findings suggest interferon gamma, an FDA-approved drug, may serve as a novel and effective prophylactic or treatment option. Using mouse-adapted Ebola virus, we found that murine interferon gamma administered 24 hours before or after infection robustly protects lethally-challenged mice and reduces morbidity and serum viral titers. Furthermore, we demonstrated that interferon gamma profoundly inhibits Ebola virus infection of macrophages, an early cellular target of infection. As early as six hours following in vitro infection, Ebola virus RNA levels in interferon gamma-treated macrophages were lower than in infected, untreated cells. Addition of the protein synthesis inhibitor, cycloheximide, to interferon gamma-treated macrophages did not further reduce viral RNA levels, suggesting that interferon gamma blocks life cycle events that require protein synthesis such as virus replication. Microarray studies with interferon gamma-treated human macrophages identified more than 160 interferon-stimulated genes. Ectopic expression of a select group of these genes inhibited Ebola virus infection. These studies provide new potential avenues for antiviral targeting as these genes that have not previously appreciated to inhibit negative strand RNA viruses and specifically Ebola virus infection. As treatment of interferon gamma robustly protects mice from lethal Ebola virus infection, we propose that interferon gamma should be further evaluated for its efficacy as a prophylactic and/or therapeutic strategy against filoviruses. Use of this FDA-approved drug could rapidly be deployed during future outbreaks. PMID:26562011

  18. Inhibition of human napsin A.

    PubMed

    Cronshaw, Rebecca F; Schauer-Vukasinovic, Vesna; Powell, David J; Giller, Thomas; Bur, Daniel; Kay, John

    2003-02-01

    The newly-discovered human aspartic proteinase, napsin A was not susceptible to protein inhibitors from potato, squash or yeast but was weakly inhibited by the 17 kDa polypeptide from Ascaris lumbricoides and potently by isovaleryl and lactoyl-pepstatins. A series of synthetic inhibitors was also investigated which contained in the P(1)-P(1)' positions the dipeptide analogue statine or its phenylalanine or cyclohexylalanine homologues and in which the residues occupying P(4)-P(3)' were varied systematically. On this basis, the active site of napsin A can be readily distinguished from other human aspartic proteinases. PMID:12625824

  19. Spider stimuli improve response inhibition.

    PubMed

    Wilson, Kyle M; Russell, Paul N; Helton, William S

    2015-05-01

    Anxiety can have positive effects on some aspects of cognition and negative effects on others. The current study investigated whether task-relevant anxiety could improve people's ability to withhold responses in a response inhibition task. Sixty-seven university students completed a modified and an unmodified version of the Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) and provided subjective measures of arousal and thoughts. Anxiety appeared to improve participants' ability to withhold responses. Further, participants' performance was consistent with a motor response inhibition perspective rather than a mind-wandering perspective of SART commission error performance. Errors of commission were associated with response times (speed-accuracy trade-off) as opposed to task-unrelated thoughts. Task-related thoughts were associated with the speed-accuracy trade-off. Conversely task-unrelated thoughts showed an association with errors of omission, suggesting this SART metric could be an indicator of sustained attention. Further investigation of the role of thoughts in the SART is warranted. PMID:25770464

  20. Graphene: corrosion-inhibiting coating.

    PubMed

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating. PMID:22299572

  1. Pharmacological inhibition of poly(ADP-ribose) polymerase inhibits angiogenesis

    SciTech Connect

    Rajesh, Mohanraj; Mukhopadhyay, Partha; Batkai, Sandor; Godlewski, Grzegorz; Hasko, Gyoergy; Liaudet, Lucas; Pacher, Pal . E-mail: pacher@mail.nih.gov

    2006-11-17

    Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which plays an important role in regulating cell death and cellular responses to DNA repair. Pharmacological inhibitors of PARP are being considered as treatment for cancer both in monotherapy as well as in combination with chemotherapeutic agents and radiation, and were also reported to be protective against untoward effects exerted by certain anticancer drugs. Here we show that pharmacological inhibition of PARP with 3-aminobenzamide or PJ-34 dose-dependently reduces VEGF-induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. These results suggest that treatment with PARP inhibitors may exert additional benefits in various cancers and retinopathies by decreasing angiogenesis.

  2. Behavioral Inhibition: Temperament or Prodrome?

    PubMed Central

    Pérez-Edgar, Koraly E.; Guyer, Amanda E.

    2014-01-01

    Individual differences in temperament emerge in the first months of life. Some infants display a heightened sensitivity to novelty and uncertainty in the world around them, leading a subset to fearfully withdraw from the social environment. Extreme forms of this temperament, Behavioral Inhibition (BI), are associated with increased risk for social anxiety disorder. Indeed, the link is so strong that some suggest that BI is not simply a risk factor for anxiety, but rather a milder form of the disorder. The current overview describes the literature linking BI and anxiety, highlighting the unique biobehavioral profiles evident in each construct. It then highlights specific evidence that may help distinguish the form and function of BI and anxiety. Finally, we briefly discuss unresolved issues that may help inform future work aimed at improving our understanding of individual development and shape therapeutic interventions directed at specific mechanisms of disorder. PMID:25101234

  3. Regulating anxiety with extrasynaptic inhibition.

    PubMed

    Botta, Paolo; Demmou, Lynda; Kasugai, Yu; Markovic, Milica; Xu, Chun; Fadok, Jonathan P; Lu, Tingjia; Poe, Michael M; Xu, Li; Cook, James M; Rudolph, Uwe; Sah, Pankaj; Ferraguti, Francesco; Lüthi, Andreas

    2015-10-01

    Aversive experiences can lead to complex behavioral adaptations including increased levels of anxiety and fear generalization. The neuronal mechanisms underlying such maladaptive behavioral changes, however, are poorly understood. Here, using a combination of behavioral, physiological and optogenetic approaches in mouse, we identify a specific subpopulation of central amygdala neurons expressing protein kinase C ? (PKC?) as key elements of the neuronal circuitry controlling anxiety. Moreover, we show that aversive experiences induce anxiety and fear generalization by regulating the activity of PKC?(+) neurons via extrasynaptic inhibition mediated by ?5 subunit-containing GABAA receptors. Our findings reveal that the neuronal circuits that mediate fear and anxiety overlap at the level of defined subpopulations of central amygdala neurons and demonstrate that persistent changes in the excitability of a single cell type can orchestrate complex behavioral changes. PMID:26322928

  4. Pharmacological Inhibition of Protein Lipidation.

    PubMed

    Ganesan, Lakshmi; Levental, Ilya

    2015-12-01

    Lipid modifications of mammalian proteins are widespread, modifying thousands of targets involved in all aspects of cellular physiology cellular physiology. Broadly, lipidations serve to increase protein hydrophobicity and association with cellular membranes. Often, these modifications are absolutely essential for protein stability and localization, and serve critical roles in dynamic regulation of protein function. A number of lipidated proteins are associated with diseases, including parasite infections, neurological diseases, diabetes, and cancer, suggesting that lipid modifications represent potentially attractive targets for pharmacological intervention. This review briefly describes the various types of posttranslational protein lipid modifications, proteins modified by them, and the enzymatic machinery associated with these. We then discuss several case studies demonstrating successful development of lipidation inhibitors of potential (and more rarely, realized) clinical value. Although this field remains in its infancy, we believe these examples demonstrate the potential utility of targeting protein lipidation as a viable strategy for inhibiting the function of pathogenic proteins. PMID:26280397

  5. Magnetic Catalysis vs Magnetic Inhibition

    E-print Network

    Kenji Fukushima; Yoshimasa Hidaka

    2012-09-06

    We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.

  6. Combined autophagy and HDAC inhibition

    PubMed Central

    Mahalingam, Devalingam; Mita, Monica; Sarantopoulos, John; Wood, Leslie; Amaravadi, Ravi K; Davis, Lisa E; Mita, Alain C; Curiel, Tyler J; Espitia, Claudia M; Nawrocki, Steffan T; Giles, Francis J; Carew, Jennifer S

    2014-01-01

    We previously reported that inhibition of autophagy significantly augmented the anticancer activity of the histone deacetylase (HDAC) inhibitor vorinostat (VOR) through a cathepsin D-mediated mechanism. We thus conducted a first-in-human study to investigate the safety, preliminary efficacy, pharmacokinetics (PK), and pharmacodynamics (PD) of the combination of the autophagy inhibitor hydroxychloroquine (HCQ) and VOR in patients with advanced solid tumors. Of 27 patients treated in the study, 24 were considered fully evaluable for study assessments and toxicity. Patients were treated orally with escalating doses of HCQ daily (QD) (d 2 to 21 of a 21-d cycle) in combination with 400 mg VOR QD (d one to 21). Treatment-related adverse events (AE) included grade 1 to 2 nausea, diarrhea, fatigue, weight loss, anemia, and elevated creatinine. Grade 3 fatigue and/or myelosuppression were observed in a minority of patients. Fatigue and gastrointestinal AE were dose-limiting toxicities. Six-hundred milligrams HCQ and 400 mg VOR was established as the maximum tolerated dose and recommended phase II regimen. One patient with renal cell carcinoma had a confirmed durable partial response and 2 patients with colorectal cancer had prolonged stable disease. The addition of HCQ did not significantly impact the PK profile of VOR. Treatment-related increases in the expression of CDKN1A and CTSD were more pronounced in tumor biopsies than peripheral blood mononuclear cells. Based on the safety and preliminary efficacy of this combination, additional clinical studies are currently being planned to further investigate autophagy inhibition as a new approach to increase the efficacy of HDAC inhibitors. PMID:24991835

  7. Inhibition in Autism: Children with Autism Have Difficulty Inhibiting Irrelevant Distractors but Not Prepotent Responses

    ERIC Educational Resources Information Center

    Adams, Nena C.; Jarrold, Christopher

    2012-01-01

    Resistance to distractor inhibition tasks have previously revealed impairments in children with autism. However, on the classic Stroop task and other prepotent response tasks, children with autism show intact inhibition. These data may reflect a distinction between prepotent response and resistance to distractor inhibition. The current study…

  8. Inhibited Power Motivation and Persuasive Communication

    E-print Network

    Schultheiss, Oliver C.

    Inhibited Power Motivation and Persuasive Communication: A Lens Model Analysis Oliver C the hypothesis that after motive arousal, individuals with an inhibited power motive (IPM) would excel-eight participants presented their point of view on a controversial subject to another person. Power motivation

  9. RESEARCH ARTICLE Iridovirus CARD Protein Inhibits Apoptosis

    E-print Network

    Gray, Matthew

    inhibited in cells expressing GIV-CARD. HeLa cells irradiated with UV or treated with anti-Fas antibody-expression of re- combinant GIV-CARD protein in HeLa cells inhibited apoptosis induced by mitochondrial and death receptor signaling. Finally, we report that expression of GIV-CARD in HeLa cells significantly reduced

  10. Thalamocortical NMDA Conductances and Intracortical Inhibition Can

    E-print Network

    Columbia University

    Abstract Cells in cerebral cortex fail to respond to fast-moving stimuli that evoke strong responses. In this circuit, inhibition dominates over excitation, but temporal modulations of excitation and inhibition occur an outstanding puzzle for the understanding of cerebral cortical circuitry. We recently introduced a model

  11. Acetylene Inhibition of Trichloroethene and Vinyl Chloride

    E-print Network

    Semprini, Lewis

    Acetylene Inhibition of Trichloroethene and Vinyl Chloride Reductive Dechlorination G E O R G E P O the biological activities of reductive dechlorination and methanogenesis. It can be added to inhibit reactions water standard (2 µg/L) (3). A variety of biochemical tools have been used to probe the complexity

  12. A Qualitative Approach to Enzyme Inhibition

    ERIC Educational Resources Information Center

    Waldrop, Grover L.

    2009-01-01

    Most general biochemistry textbooks present enzyme inhibition by showing how the basic Michaelis-Menten parameters K[subscript m] and V[subscript max] are affected mathematically by a particular type of inhibitor. This approach, while mathematically rigorous, does not lend itself to understanding how inhibition patterns are used to determine the…

  13. Inhibition: Mental Control Process or Mental Resource?

    ERIC Educational Resources Information Center

    Im-Bolter, Nancie; Johnson, Janice; Ling, Daphne; Pascual-Leone, Juan

    2015-01-01

    The current study tested 2 models of inhibition in 45 children with language impairment and 45 children with normally developing language; children were aged 7 to 12 years. Of interest was whether a model of inhibition as a mental-control process (i.e., executive function) or as a mental resource would more accurately reflect the relations among…

  14. Factors Impacting the Child with Behavioral Inhibition

    ERIC Educational Resources Information Center

    Hornbuckle, Suzanne R.

    2010-01-01

    Various factors influence the developmental course of the behaviorally inhibited child. These factors include reciprocating, contextual factors, such as the child's own traits, the environment, the maternal characteristics, and the environment. Behaviorally inhibited children show physiological and behavioral signs of fear and anxiety when…

  15. Optimal Decision Making in Neural Inhibition Models

    ERIC Educational Resources Information Center

    van Ravenzwaaij, Don; van der Maas, Han L. J.; Wagenmakers, Eric-Jan

    2012-01-01

    In their influential "Psychological Review" article, Bogacz, Brown, Moehlis, Holmes, and Cohen (2006) discussed optimal decision making as accomplished by the drift diffusion model (DDM). The authors showed that neural inhibition models, such as the leaky competing accumulator model (LCA) and the feedforward inhibition model (FFI), can mimic the…

  16. Basic models for differential inhibition of enzymes.

    PubMed

    Cappiello, Mario; Moschini, Roberta; Balestri, Francesco; Mura, Umberto; Del-Corso, Antonella

    2014-03-14

    The possible preferential action exerted by an inhibitor on the transformation of one of two agonist substrates catalyzed by the same enzyme has recently been reported in studies on aldose reductase inhibition. This event was defined as "intra-site differential inhibition" and the molecules able to exert this action as "differential inhibitors". This work presents some basic kinetic models describing differential inhibition. Using a simple analytic approach, the results show that differential inhibition can occur through either competitive or mixed type inhibition in which the inhibitor prevalently targets the free enzyme. The results may help in selecting molecules whose differential inhibitory action could be advantageous in controlling the activity of enzymes acting on more than one substrate. PMID:24530393

  17. Shed syndecan-2 inhibits angiogenesis

    PubMed Central

    De Rossi, Giulia; Evans, Alun R.; Kay, Emma; Woodfin, Abigail; McKay, Tristan R.; Nourshargh, Sussan; Whiteford, James R.

    2014-01-01

    ABSTRACT Angiogenesis is essential for the development of a normal vasculature, tissue repair and reproduction, and also has roles in the progression of diseases such as cancer and rheumatoid arthritis. The heparan sulphate proteoglycan syndecan-2 is expressed on mesenchymal cells in the vasculature and, like the other members of its family, can be shed from the cell surface resulting in the release of its extracellular core protein. The purpose of this study was to establish whether shed syndecan-2 affects angiogenesis. We demonstrate that shed syndecan-2 regulates angiogenesis by inhibiting endothelial cell migration in human and rodent models and, as a result, reduces tumour growth. Furthermore, our findings show that these effects are mediated by the protein tyrosine phosphatase receptor CD148 (also known as PTPRJ) and this interaction corresponds with a decrease in active ?1 integrin. Collectively, these data demonstrate an unexplored pathway for the regulation of new blood vessel formation and identify syndecan-2 as a therapeutic target in pathologies characterised by angiogenesis. PMID:25179601

  18. Prepulse inhibition and latent inhibition: the role of dopamine in the medial prefrontal cortex.

    PubMed

    Ellenbroek, B A; Budde, S; Cools, A R

    1996-11-01

    The prefrontal cortex has often been implicated in the pathophysiology of schizophrenia. Schizophrenic patients are known to suffer from certain information processing deficits, which can be detected, among others, in the prepulse inhibition and the latent inhibition paradigm. The present study was designed to investigate the role of dopamine receptors in the medial prefrontal cortex in prepulse inhibition and latent inhibition. The results show that the local application of the selective antagonist of the dopamine D1-like receptor family, SCH 39166, into the medial prefrontal cortex dose-dependently reduced prepulse inhibition. Likewise, the selective antagonist of the dopamine D2-like receptor family, sulpiride, injected into the medial prefrontal cortex dose-dependently reduced prepulse inhibition. Neither of these antagonists, however, influenced latent inhibition as measured with the conditioned taste aversion paradigm. These data further indicate that the neuronal substrates of latent inhibition and prepulse inhibition are clearly different. Since the prefrontal cortex is intimately related to subcortical dopamine, the possible differential involvement of subcortical dopaminergic terminal fields in prepulse inhibition and latent inhibition is discussed. PMID:8931016

  19. Structural and functional bases of inhibited temperament.

    PubMed

    Clauss, Jacqueline A; Seay, April L; VanDerKlok, Ross M; Avery, Suzanne N; Cao, Aize; Cowan, Ronald L; Benningfield, Margaret M; Blackford, Jennifer Urbano

    2014-12-01

    Children born with an inhibited temperament are at heightened risk for developing anxiety, depression and substance use. Inhibited temperament is believed to have a biological basis; however, little is known about the structural brain basis of this vulnerability trait. Structural MRI scans were obtained from 84 (44 inhibited, 40 uninhibited) young adults. Given previous findings of amygdala hyperactivity in inhibited individuals, groups were compared on three measures of amygdala structure. To identify novel substrates of inhibited temperament, a whole brain analysis was performed. Functional activation and connectivity were examined across both groups. Inhibited adults had larger amygdala and caudate volume and larger volume predicted greater activation to neutral faces. In addition, larger amygdala volume predicted greater connectivity with subcortical and higher order visual structures. Larger caudate volume predicted greater connectivity with the basal ganglia, and less connectivity with primary visual and auditory cortex. We propose that larger volume in these salience detection regions may result in increased activation and enhanced connectivity in response to social stimuli. Given the strong link between inhibited temperament and risk for psychiatric illness, novel therapeutics that target these brain regions and related neural circuits have the potential to reduce rates of illness in vulnerable individuals. PMID:24493850

  20. Regulation of spatial selectivity by crossover inhibition.

    PubMed

    Cafaro, Jon; Rieke, Fred

    2013-04-10

    Signals throughout the nervous system diverge into parallel excitatory and inhibitory pathways that later converge on downstream neurons to control their spike output. Converging excitatory and inhibitory synaptic inputs can exhibit a variety of temporal relationships. A common motif is feedforward inhibition, in which an increase (decrease) in excitatory input precedes a corresponding increase (decrease) in inhibitory input. The delay of inhibitory input relative to excitatory input originates from an extra synapse in the circuit shaping inhibitory input. Another common motif is push-pull or "crossover" inhibition, in which increases (decreases) in excitatory input occur together with decreases (increases) in inhibitory input. Primate On midget ganglion cells receive primarily feedforward inhibition and On parasol cells receive primarily crossover inhibition; this difference provides an opportunity to study how each motif shapes the light responses of cell types that play a key role in visual perception. For full-field stimuli, feedforward inhibition abbreviated and attenuated responses of On midget cells, while crossover inhibition, though plentiful, had surprisingly little impact on the responses of On parasol cells. Spatially structured stimuli, however, could cause excitatory and inhibitory inputs to On parasol cells to increase together, adopting a temporal relation very much like that for feedforward inhibition. In this case, inhibitory inputs substantially abbreviated a cell's spike output. Thus inhibitory input shapes the temporal stimulus selectivity of both midget and parasol ganglion cells, but its impact on responses of parasol cells depends strongly on the spatial structure of the light inputs. PMID:23575830

  1. Regulation of Spatial Selectivity by Crossover Inhibition

    PubMed Central

    Cafaro, Jon; Rieke, Fred

    2013-01-01

    Signals throughout the nervous system diverge into parallel excitatory and inhibitory pathways that later converge on downstream neurons to control their spike output. Converging excitatory and inhibitory synaptic inputs can exhibit a variety of temporal relationships. A common motif is feedforward inhibition, in which an increase (decrease) in excitatory input precedes a corresponding increase (decrease) in inhibitory input. The delay of inhibitory input relative to excitatory input originates from an extra synapse in the circuit shaping inhibitory input. Another common motif is push-pull or “crossover” inhibition, in which increases (decreases) in excitatory input occur together with decreases (increases) in inhibitory input. Primate On midget ganglion cells receive primarily feedforward inhibition and On parasol cells receive primarily crossover inhibition; this difference provides an opportunity to study how each motif shapes the light responses of cell types that play a key role in visual perception. For full-field stimuli, feedforward inhibition abbreviated and attenuated responses of On midget cells, while crossover inhibition, though plentiful, had surprisingly little impact on the responses of On parasol cells. Spatially structured stimuli, however, could cause excitatory and inhibitory inputs to On parasol cells to increase together, adopting a temporal relation very much like that for feedforward inhibition. In this case, inhibitory inputs substantially abbreviated a cell’s spike output. Thus inhibitory input shapes the temporal stimulus selectivity of both midget and parasol ganglion cells, but its impact on responses of parasol cells depends strongly on the spatial structure of the light inputs. PMID:23575830

  2. Inhibition of muscle force by vanadate.

    PubMed Central

    Wilson, G J; Shull, S E; Cooke, R

    1995-01-01

    Vanadate (Vi), an analogue of inorganic phosphate (Pi), is known to bind tightly with a long half life to the myosin MgATPase site, producing a complex which inhibits force. Both of these ligands bind to an actin.myosin.ADP state that follows the release of Pi in the enzymatic cycle, and their effects on muscle fibers and proteins in solution provide information on the properties of this state. The inhibition of active force generation began to occur at a [Vi] of 5 microM and was 90% complete at a [Vi] of 1 mM. Hill plots of the inhibition of force by Vi approximated that expected for a simple binding isotherm. Similar plots were obtained at both 25 degrees C and 5 degrees C. A simple binding isotherm is not expected to occur in a muscle fiber where steric constraints imposed by the intact filaments should introduce more complexity into the energetics of ligand binding. The inhibition of MgATPase activity for acto-subfragment-1 to 50% of controls occurred at a [Vi] which was only 20-fold higher than that required to inhibit force generation in fibers to the same level. Some models of actomyosin interactions would predict that the range of [Vi] required for complete force inhibition in fibers and the difference in the [Vi] required for inhibition in fibers and of myosin in solution would both be much larger. PMID:7711244

  3. Optogenetic inhibition of cocaine seeking in rats.

    PubMed

    Stefanik, Michael T; Moussawi, Khaled; Kupchik, Yonatan M; Smith, Kyle C; Miller, Rachel L; Huff, Mary L; Deisseroth, Karl; Kalivas, Peter W; LaLumiere, Ryan T

    2013-01-01

    Inhibitory optogenetics was used to examine the roles of the prelimbic cortex (PL), the nucleus accumbens core (NAcore) and the PL projections to the NAcore in the reinstatement of cocaine seeking. Rats were microinjected into the PL or NAcore with an adeno-associated virus containing halorhodopsin or archaerhodopsin. After 12 days of cocaine self-administration, followed by extinction training, animals underwent reinstatement testing along with the presence/absence of optically induced inhibition via laser light. Bilateral optical inhibition of the PL, NAcore or the PL fibers in the NAcore inhibited the reinstatement of cocaine seeking. PMID:22823160

  4. Praziquantel inhibits Schistosoma mansoni attachment in vitro.

    PubMed

    da-Silva, S P; Noel, F

    1990-01-01

    Male adult Schistosoma mansoni worms were placed in a glass dish containing Tyrode solution and observed for 15 min after addition of praziquantel (0.01 to 1 microM). Praziquantel promoted a concentration- and time-dependent inhibition of sucker-mediated attachment of the worm. Attachment inhibition was correlated with shortening of the parasite. We propose that the rapid and total inhibition of worm attachment observed in vitro with 1 microM praziquantel indicates that therapeutic concentrations of this drug should promote a rapid hepatic shift, in vivo, which may facilitate host tissue reaction. PMID:2101049

  5. Glycerol inhibition of ruminal lipolysis in vitro

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supplemental glycerol inhibits rumen lipolysis, a prerequisite for rumen biohydrogenation, which is responsible for the saturation of dietary fatty acids consumed by ruminant animals. Feeding excess glycerol, however, adversely affects dry matter digestibility. To more clearly define the effect of...

  6. Toxicants inhibiting anaerobic digestion: a review.

    PubMed

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion. PMID:25457225

  7. Inhibition of urinary calculi -- a spectroscopic study

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Govani, Jayesh; Durrer, William; Reza, Layra; Pinales, Luis

    2008-10-01

    Although a considerable number of investigations have already been undertaken and many causes such as life habits, metabolic disorders, and genetic factors have been noted as sources that accelerate calculi depositions and aggregations, there are still plenty of unanswered questions regarding efficient inhibition and treatment mechanisms. Thus, in an attempt to acquire more insights, we propose here a detailed scientific study of kidney stone formation and growth inhibition based on a traditional medicine approach with Rotula Aquatica Lour (RAL) herbal extracts. A simplified single diffusion gel growth technique was used for synthesizing the samples for the present study. The unexpected Zn presence in the sample with RAL inhibitor, as revealed by XPS measurements, explains the inhibition process and the dramatic reflectance of the incident light observed in the infrared transmission studies. Raman data demonstrate potential binding of the inhibitor with the oxygen of the kidney stone. Photoluminescence results corroborate to provide additional evidence of Zn-related inhibition.

  8. Quorum Sensing Inhibition, Relevance to Periodontics

    PubMed Central

    Yada, Sudheer; Kamalesh, B; Sonwane, Siddharth; Guptha, Indra; Swetha, R K

    2015-01-01

    Quorum sensing helps bacteria to communicate with each other and in coordinating their behavior. Many diseases of human beings, plants, and animals are mediated by quorum sensing. Various approaches are being tried to inhibit this communication to control the diseases caused by bacteria. Periodontal pathogens also communicate through quorum sensing and new approaches to treat periodontal disease using quorum sensing inhibition need to explored. PMID:25709373

  9. Inhibited solid propellant composition containing beryllium hydride

    NASA Technical Reports Server (NTRS)

    Thompson, W. W. (inventor)

    1978-01-01

    An object of this invention is to provide a composition of beryllium hydride and carboxy-terminated polybutadiene which is stable. Another object of this invention is to provide a method for inhibiting the reactivity of beryllium hydride toward carboxy-terminated polybutadiene. It was found that a small amount of lecithin inhibits the reaction of beryllium hydride with the acid groups in carboxy terminated polybutadiene.

  10. Activin inhibits telomerase activity in cancer

    SciTech Connect

    Katik, Indzi; Mackenzie-Kludas, Charley; Nicholls, Craig; Jiang, Fang-Xu; Zhou, Shufeng; Li, He; Liu, Jun-Ping

    2009-11-27

    Activin is a pleiotropic cytokine with broad tissue distributions. Recent studies demonstrate that activin-A inhibits cancer cell proliferation with unknown mechanisms. In this report, we demonstrate that recombinant activin-A induces telomerase inhibition in cancer cells. In breast and cervical cancer cells, activin-A resulted in telomerase activity in a concentration-dependent manner. Significant inhibition was observed at 10 ng/ml of activin-A, with a near complete inhibition at 80 ng/ml. Consistently, activin-A induced repression of the telomerase reverse transcriptase (hTERT) gene, with the hTERT gene to be suppressed by 60-80% within 24 h. In addition, activin-A induced a concomitant increase in Smad3 signaling and decrease of the hTERT gene promoter activity in a concentration-dependent fashion. These data suggest that activin-A triggered telomerase inhibition by down-regulating hTERT gene expression is involved in activin-A-induced inhibition of cancer cell proliferation.

  11. Piperine, a dietary phytochemical, inhibits angiogenesis

    PubMed Central

    Doucette, Carolyn D.; Hilchie, Ashley L.; Liwski, Robert; Hoskin, David W.

    2012-01-01

    Angiogenesis plays an important role in tumor progression. Piperine, a major alkaloid constituent of black pepper, has diverse physiological actions including killing of cancer cells; however, the effect of piperine on angiogenesis is not known. Here we show that piperine inhibited the proliferation and G1/S transition of human umbilical vein endothelial cells (HUVECs) without causing cell death. Piperine also inhibited HUVEC migration and tubule formation in vitro, as well as collagen-induced angiogenic activity by rat aorta explants and breast cancer cell-induced angiogenesis in chick embryos. Although piperine binds to and activates the cation channel transient receptor potential vanilloid 1 (TRPV1), its effects on endothelial cells did not involve TRPV1 since the antiproliferative effect of piperine was not affected by TRPV1-selective antagonists, nor did HUVECs express detectable TRPV1 mRNA. Importantly, piperine inhibited phosphorylation of Ser 473 and Thr 308 residues of Akt (protein kinase B), which is a key regulator of endothelial cell function and angiogenesis. Consistent with Akt inhibition as the basis of piperine’s action on HUVECs, inhibition of the phosphoinositide-3 kinase/Akt signaling pathway with LY-294002 also inhibited HUVEC proliferation and collagen-induced angiogenesis. Taken together, these data support the further investigation of piperine as an angiogenesis inhibitor for use in cancer treatment. PMID:22902327

  12. Mast cell stabilization, lipoxygenase inhibition, hyaluronidase inhibition, antihistaminic and antispasmodic activities of Aller-7, a novel botanical formulation for allergic rhinitis.

    PubMed

    Amit, A; Saxena, V S; Pratibha, N; D'Souza, P; Bagchi, M; Bagchi, D; Stohs, S J

    2003-01-01

    Allergic rhinitis, also known as hay fever, rose fever or summer catarrh, is a major challenge to health professionals. A large number of the world's population, including approximately 40 million Americans, suffers from allergic rhinitis. A novel, botanical formulation (Aller-7) has been developed for the treatment of allergic rhinitis using a combination of extracts from seven medicinal plants, including Phyllanthus emblica, Terminalia chebula, T. bellerica, Albizia lebbeck, Piper nigrum, Zingiber officinale and P. longum, which have a proven history of efficacy and health benefits. The clinical manifestations of allergy are due to a number of mediators that are released from mast cells. The effect of Aller-7 on rat mesenteric mast cell degranulation was studied by incubating different concentrations of Aller-7 and challenging them with a degranulating agent, compound 48/80. The inhibitory activity of Aller-7 was determined against lipoxygenase and hyaluronidase, the key enzymes involved in the initiation and maintenance of inflammatory responses. Furthermore, most of these manifestations are due to histamine, which causes vasodilatation, increasing capillary permeability and leading to bronchoconstriction. Hence, the antihistaminic activity of Aller-7 was determined is isolated guinea pig ileum substrate using cetirizine as a positive control. The antispasmodic effect of Aller-7 on contractions of guinea pig tracheal chain was determined using papaverine and cetirizine as controls. Aller-7 exhibited potent activity in all these in vitro models tested, thus demonstrating the novel anti-allergic potential of Aller-7. PMID:14708456

  13. Magnesium inhibition of calcite dissolution kinetics

    SciTech Connect

    Arvidson, Rolf S.; Collier, Martin; Davis, Kevin J.; Vinson, Michael D.; Amonette, James E.; Luttge, Andreas

    2006-02-01

    We present evidence of inhibition of calcite dissolution by dissolved magnesium through direct observations of the (104) surface using atomic force microscopy (AFM) and vertical scanning interferometry (VSI). Far from equilibrium, the pattern of magnesium inhibition is dependent on solution composition and specific to surface step geometry. In CO2-free solutions (pH 8.8), dissolved magnesium brings about little inhibition even at concentrations of 0.8 x 10-3 molal. At the same pH, magnesium concentrations of less than 0.05 x 10-3 molal in carbonate-buffered solutions generate significant inhibition, although no changes in surface and etch pit morphology are observed. As concentrations exceed magnesite saturation, the dissolution rate shows little additional decrease; however, selective pinning of step edges results in unique etch-pit profiles, seen in both AFM and VSI datasets. Despite the decreases in step velocity, magnesium addition in carbonated solutions also appears to activate the surface by increasing the nucleation rate of new defects. These relationships suggest that the modest depression of the bulk rate measured by VSI reflects a balance between competing reaction mechanisms that simultaneously depress the rate through selective inhibition of step movement, but also enhance reactivity on terraces by lowering the energy barrier to new etch-pit formation.

  14. Ribavirin inhibits angiogenesis by tetrahydrobiopterin depletion.

    PubMed

    Michaelis, Martin; Michaelis, Ruth; Suhan, Tatyana; Schmidt, Helmut; Mohamed, Annisuddin; Doerr, Hans Wilhelm; Cinatl, Jindrich

    2007-01-01

    Ribavirin is a broad-spectrum antiviral drug that is used to treat hepatitis C virus (HCV)-infected patients. The virological response after ribavirin treatment appears to be insufficient to fully explain ribavirin-induced beneficial effects. Angiogenesis plays a pathogenic role in HCV-induced liver damage. Here, we investigated the influence of therapeutic ribavirin concentrations on angiogenesis. Ribavirin inhibited endothelial cell tube formation in vitro and vessel formation in the chick chorioallantoic membrane assay in vivo. Ribavirin inhibits inosine monophosphate dehydrogenase, which causes depletion of cellular GTP and in turn reduction of cellular tetrahydrobiopterin levels. The availability of tetrahydrobiopterin limits NO production by endothelial NO synthase. Ribavirin reduced levels of tetrahydrobiopterin (as revealed by HPLC), NO (as revealed by electron spin resonance spectroscopy), and cGMP (as revealed by RIA) in endothelial cells. Addition of tetrahydrobiopterin or NO prevented ribavirin-induced tube formation inhibition. In conclusion, angiogenesis inhibition by ribavirin has not been described before. This inhibition may contribute to ribavirin-induced pharmacological effects including adverse events. PMID:17135367

  15. Enhanced response inhibition in experienced fencers

    PubMed Central

    Zhang, Dandan; Ding, Haiyan; Wang, Xiaochun; Qi, Changzhu; Luo, Yuejia

    2015-01-01

    The inhibition of a prepotent response is an essential executive function which enables us to suppress inappropriate actions in a given context. Individuals with fencing expertise exhibit behavioral advantages on tasks with high demands on response inhibition. This study examines the electrophysiological basis for the superior response inhibition in experienced fencers. In the Go/Nogo task where frequent stimuli required a motor response while reaction had to be withheld to rare stimuli, the fencers, compared with the non-fencers, exhibited behavioral as well as electrophysiological advantages when suppressing prepotent responses. The superior response inhibition in the fencers was characterized by enhanced Nogo-N2 and reduced Nogo-P3. Single-trial analysis revealed that the amplitude difference of the Nogo-N2 between two groups was caused by lower single-trial latency variability in the fencers (may be due to low attentional fluctuation and/or stable neural processing speed) while the amplitude difference of the Nogo-P3 resulted from truly weaker neural activity in the fencers (may be because few cognitive sources are needed and few control efforts are made). The two inhibition-related components are distinct neurophysiological indexes that, on the one hand, provide effective guidance to titrate the level of executive function in fencers, and on the other hand, facilitate to monitor fencers’ improvement in the training process. PMID:26541899

  16. Enhanced response inhibition in experienced fencers.

    PubMed

    Zhang, Dandan; Ding, Haiyan; Wang, Xiaochun; Qi, Changzhu; Luo, Yuejia

    2015-01-01

    The inhibition of a prepotent response is an essential executive function which enables us to suppress inappropriate actions in a given context. Individuals with fencing expertise exhibit behavioral advantages on tasks with high demands on response inhibition. This study examines the electrophysiological basis for the superior response inhibition in experienced fencers. In the Go/Nogo task where frequent stimuli required a motor response while reaction had to be withheld to rare stimuli, the fencers, compared with the non-fencers, exhibited behavioral as well as electrophysiological advantages when suppressing prepotent responses. The superior response inhibition in the fencers was characterized by enhanced Nogo-N2 and reduced Nogo-P3. Single-trial analysis revealed that the amplitude difference of the Nogo-N2 between two groups was caused by lower single-trial latency variability in the fencers (may be due to low attentional fluctuation and/or stable neural processing speed) while the amplitude difference of the Nogo-P3 resulted from truly weaker neural activity in the fencers (may be because few cognitive sources are needed and few control efforts are made). The two inhibition-related components are distinct neurophysiological indexes that, on the one hand, provide effective guidance to titrate the level of executive function in fencers, and on the other hand, facilitate to monitor fencers' improvement in the training process. PMID:26541899

  17. Inhibition of ethylene production by putrescine alleviates aluminium-induced root inhibition in wheat plants.

    PubMed

    Yu, Yan; Jin, Chongwei; Sun, Chengliang; Wang, Jinghong; Ye, Yiquan; Zhou, Weiwei; Lu, Lingli; Lin, Xianyong

    2016-01-01

    Inhibition of root elongation is one of the most distinct symptoms of aluminium (Al) toxicity. Although putrescine (Put) has been identified as an important signaling molecule involved in Al tolerance, it is yet unknown how Put mitigates Al-induced root inhibition. Here, the possible mechanism was investigated by using two wheat genotypes differing in Al resistance: Al-tolerant Xi Aimai-1 and Al-sensitive Yangmai-5. Aluminium caused more root inhibition in Yangmai-5 and increased ethylene production at the root apices compared to Xi Aimai-1, whereas the effects were significantly reversed by ethylene biosynthesis inhibitors. The simultaneous exposure of wheat seedlings to Al and ethylene donor, ethephon, or ethylene biosynthesis precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), increased ethylene production and aggravated root inhibition, which was more pronounced in Xi Aimai-1. In contrast, Put treatment decreased ethylene production and alleviated Al-induced root inhibition in both genotypes, and the effects were more conspicuous in Yangmai-5. Furthermore, our results indicated that Al-induced ethylene production was mediated by ACC synthase (ACS) and ACC oxidase, and that Put decreased ethylene production by inhibiting ACS. Altogether, these findings indicate that ethylene is involved in Al-induced root inhibition and this process could be alleviated by Put through inhibiting ACS activity. PMID:26744061

  18. The role of (dis)inhibition in creativity: decreased inhibition improves idea generation.

    PubMed

    Radel, Rémi; Davranche, Karen; Fournier, Marion; Dietrich, Arne

    2015-01-01

    There is now a large body of evidence showing that many different conditions related to impaired fronto-executive functioning are associated with the enhancement of some types of creativity. In this paper, we pursue the possibility that the central mechanism associated with this effect might be a reduced capacity to exert inhibition. We tested this hypothesis by exhausting the inhibition efficiency through prolonged and intensive practice of either the Simon or the Eriksen Flanker task. Performance on another inhibition task indicated that only the cognitive resources for inhibition of participants facing high inhibition demands were impaired. Subsequent creativity tests revealed that exposure to high inhibition demands led to enhanced fluency in a divergent thinking task (Alternate Uses Task), but no such changes occurred in a convergent task (Remote Associate Task; studies 1a and 1b). The same manipulation also led to a hyper-priming effect for weakly related primes in a Lexical Decision Task (Study 2). Together, these findings suggest that inhibition selectively affects some types of creative processes and that, when resources for inhibition are lacking, the frequency and the originality of ideas was facilitated. PMID:25460384

  19. Inhibition of 5-lipoxygenase by vitamin E.

    PubMed

    Reddanna, P; Rao, M K; Reddy, C C

    1985-11-25

    Purified 5-lipoxygenase from potato tubers was inhibited strongly by vitamin E and its analogs. The inhibition by d-alpha-tocopherol was found to be irreversible and non-competitive with respect to arachidonic acid. An IC50 of 5 microM was calculated for d-alpha-tocopherol. The inhibition appears to be unrelated to its antioxidant function. Binding studies with 14C-labelled d-alpha-tocopherol revealed that there is a strong interaction between vitamin E and 5-lipoxygenase. Tryptic digestion and peptide mapping of 5-lipoxygenase-vitamin E complex indicate that vitamin E binds strongly to a single peptide. These studies suggest that cellular vitamin E levels may have profound influence on the formation of leukotrienes. PMID:3934003

  20. Distractor inhibition: Evidence from lateralized readiness potentials.

    PubMed

    Pramme, Lisa; Dierolf, Angelika M; Naumann, Ewald; Frings, Christian

    2015-08-01

    The present study investigated distractor inhibition on the level of stimulus representation. In a sequential distractor-to-distractor priming task participants had to respond to target letters flanked by distractor digits. Reaction time and stimulus-locked lateralized readiness potentials (S-LRPs) of probe responses were measured. Distractor-target onset asynchrony was varied. For RTs responses to probe targets were faster in the case of prime-distractor repetition compared to distractor changes indicating distractor inhibition. Benefits in RTs and the latency of S-LRP onsets for distractor repetition were also modulated by distractor-target onset asynchrony. For S-LRPs distractor inhibition was only present with a simultaneous onset of distractors and target. The results confirm previous results indicating inhibitory mechanisms of object-based selective attention on the level of distractor representations. PMID:26114922

  1. Inhibiting macrophage proliferation suppresses atherosclerotic plaque inflammation

    PubMed Central

    Tang, Jun; Lobatto, Mark E.; Hassing, Laurien; van der Staay, Susanne; van Rijs, Sarian M.; Calcagno, Claudia; Braza, Mounia S.; Baxter, Samantha; Fay, Francois; Sanchez-Gaytan, Brenda L.; Duivenvoorden, Raphaël; Sager, Hendrik; Astudillo, Yaritzy M.; Leong, Wei; Ramachandran, Sarayu; Storm, Gert; Pérez-Medina, Carlos; Reiner, Thomas; Cormode, David P.; Strijkers, Gustav J.; Stroes, Erik S.G.; Swirski, Filip K.; Nahrendorf, Matthias; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J.M.

    2015-01-01

    Inflammation drives atherosclerotic plaque progression and rupture, and is a compelling therapeutic target. Consequently, attenuating inflammation by reducing local macrophage accumulation is an appealing approach. This can potentially be accomplished by either blocking blood monocyte recruitment to the plaque or increasing macrophage apoptosis and emigration. Because macrophage proliferation was recently shown to dominate macrophage accumulation in advanced plaques, locally inhibiting macrophage proliferation may reduce plaque inflammation and produce long-term therapeutic benefits. To test this hypothesis, we used nanoparticle-based delivery of simvastatin to inhibit plaque macrophage proliferation in apolipoprotein E deficient mice (Apoe?/?) with advanced atherosclerotic plaques. This resulted in rapid reduction of plaque inflammation and favorable phenotype remodeling. We then combined this short-term nanoparticle intervention with an eight-week oral statin treatment, and this regimen rapidly reduced and continuously suppressed plaque inflammation. Our results demonstrate that pharmacologically inhibiting local macrophage proliferation can effectively treat inflammation in atherosclerosis. PMID:26295063

  2. Complete corrosion inhibition through graphene defect passivation.

    PubMed

    Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

    2014-01-28

    Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ?50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods. PMID:24359599

  3. Surface modification for aluminium pigment inhibition.

    PubMed

    Karlsson, Philip; Palmqvist, Anders E C; Holmberg, Krister

    2006-12-21

    This review concerns surface treatment of aluminium pigments for use in water borne coatings. Aluminium pigments are commonly used in coatings to give a silvery and shiny lustre to the substrate. Such paints and inks have traditionally been solvent borne, since aluminium pigment particles react with water. For environmental and health reasons solvent borne coatings are being replaced by water borne and the aluminium pigments then need to be surface modified in order to stand exposure to water. This process is called inhibition and both organic and inorganic substances are used as inhibiting agents. The organic inhibiting agents range from low molecular weight substances, such as phenols and aromatic acids, via surfactants, in particular alkyl phosphates and other anionic amphiphiles, to high molecular weight compounds, such as polyelectrolytes. A common denominator for them all is that they contain a functional group that interacts specifically with aluminium at the surface. A particularly strong interaction is obtained if the inhibiting agent contains functional groups that form chelating complex with surface Al(III). Encapsulation of the pigment can be made by in situ polymerization at the surface of the pigment and a recent approach is to have the polymerization occur within a double layer of adsorbed surfactant. The inorganic route is dominated by coating with silica, and recent progress has been made using an alkoxide, such as tetraethoxysilane as silica precursor. Such silica coated aluminium pigments are comparable in performance to chromate inhibited pigments and thus offer a possible heavy metal-free alternative. There are obvious connections between surface modifications made to prevent the pigment to react with water and inhibition of corrosion of macroscopic aluminium surfaces. PMID:17239333

  4. In Vivo Activation of Human NK Cells by Treatment with an Interleukin-15 Superagonist Potently Inhibits Acute In Vivo HIV-1 Infection in Humanized Mice

    PubMed Central

    Seay, Kieran; Church, Candice; Zheng, Jian Hua; Deneroff, Kathryn; Ochsenbauer, Christina; Kappes, John C.; Liu, Bai; Jeng, Emily K.; Wong, Hing C.

    2015-01-01

    ABSTRACT Natural killer (NK) cells with anti-HIV-1 activity may inhibit HIV-1 replication and dissemination during acute HIV-1 infection. We hypothesized that the capacity of NK cells to suppress acute in vivo HIV-1 infection would be augmented by activating them via treatment with an interleukin-15 (IL-15) superagonist, IL-15 bound to soluble IL-15R?, an approach that potentiates human NK cell-mediated killing of tumor cells. In vitro stimulation of human NK cells with a recombinant IL-15 superagonist significantly induced their expression of the cytotoxic effector molecules granzyme B and perforin; their degranulation upon exposure to K562 cells, as indicated by cell surface expression of CD107a; and their capacity to lyse K562 cells and HIV-1-infected T cells. The impact of IL-15 superagonist-induced activation of human NK cells on acute in vivo HIV-1 infection was investigated by using hu-spl-PBMC-NSG mice, NOD-SCID-IL2r??/? (NSG) mice intrasplenically injected with human peripheral blood mononuclear cells (PBMCs) which develop productive in vivo infection after intrasplenic inoculation with HIV-1. IL-15 superagonist treatment potently inhibited acute HIV-1 infection in hu-spl-PBMC-NSG mice even when delayed until 3 days after intrasplenic HIV-1 inoculation. Removal of NK cells from human PBMCs prior to intrasplenic injection into NSG mice completely abrogated IL-15 superagonist-mediated suppression of in vivo HIV-1 infection. Thus, the in vivo activation of NK cells, integral mediators of the innate immune response, by treatment with an IL-15 superagonist increases their anti-HIV activity and enables them to potently suppress acute in vivo HIV-1 infection. These results indicate that in vivo activation of NK cells may represent a new immunotherapeutic approach to suppress acute HIV-1 infection. IMPORTANCE Epidemiological studies have indicated that NK cells contribute to the control of HIV-1 infection, and in vitro studies have demonstrated that NK cells can selectively kill HIV-1-infected cells. We demonstrated that in vivo activation of NK cells by treatment with an IL-15 superagonist that potently stimulates the antitumor activity of NK cells markedly inhibited acute HIV-1 infection in humanized mice, even when activation of NK cells by IL-15 superagonist treatment is delayed until 3 days after HIV-1 inoculation. NK cell depletion from PBMCs prior to their intrasplenic injection abrogated the suppression of in vivo HIV-1 infection observed in humanized mice treated with the IL-15 superagonist, demonstrating that activated human NK cells were mediating IL-15 superagonist-induced inhibition of acute HIV-1 infection. Thus, in vivo immunostimulation of NK cells, a promising therapeutic approach for cancer therapy, may represent a new treatment modality for HIV-1-infected individuals, particularly in the earliest stages of infection. PMID:25833053

  5. Experimental studies of inhibited counterflow flames

    NASA Astrophysics Data System (ADS)

    Truett, Leonard Franklin, III

    An experimental and numerical study was performed to investigate the fundamental mechanisms of chemical inhibition. The first part of this work examined the structure of non-premixed counterflow methane-air flames. Gas samples were taken with a quartz microprobe and analyzed using a gas chromatograph with a thermal conductivity detector. Experimental and detailed numerical results were obtained for an uninhibited flame and flames inhibited by 1.5% CF3Br and 1.5% CF3I added to the oxidizer, all with a strain rate of 150s-1. The experimental data showed a slight shift toward the oxidizer duct above the flame, but showed excellent agreement with the numerical results below the flame in all cases. The inhibiting effect of CF3Br on a non-premixed diluted hydrogen-air flame was also investigated in the counterflowing configuration. Extinction results were obtained for 15%H2/85%N2 and 16%H 2/84%N2 in the fuel stream. The experimental results supported the theory that carbon chemistry does not play a significant role in inhibition by CF3Br. These results were compared with two different numerical models with different inhibition mechanisms. The effect of partially premixing a methane-air counterflow flame on the extinction strain rate was also examined. Premixing the oxidizer flow had a stabilizing effect, premixing the fuel flow had a weak inhibiting effect, and premixing in both flows had a very weak stabilizing effect that was basically the average of the two individual cases. These results were compared with detailed calculations, asymptotic and one-step analysis. The detailed numerical calculations had excellent agreement with the experiments but the asymptotic and one-step analysis predicted incorrect trends for all cases. Tests were also performed to examine the inhibiting effectiveness of alkali metal salts. Experiments were performed with NaHCO3 and KHCO3 with particle sizes of <30 microns and <20 microns, NaBr and KBr with a particle size of 5--25 microns, and silica (SiO 2) with a particle size of 1--3 microns. Inhibiting effectiveness increased as the particle sized decreased for all powders. The KHCO3 was approximately twice as effective as the NaHCO3, NaBr and KBr for similar particle sizes. These powders were approximately 10 times more efficient than silica and CF3Br on a mass basis.

  6. Crossed disynaptic inhibition of sacral motoneurones.

    PubMed

    Jankowska, E; Padel, Y; Zarzecki, P

    1978-12-01

    1. Intracellular recording was made from motoneurones in lower sacral (S2 and S3) segments of the spinal cord in cats, to analyse the neuronal organization of the inhibition evoked in these motoneurones from contralateral afferents. 2. It was confirmed that stimulation of the lowest threshold afferents of contralateral dorsal roots evokes i.p.s.p.s with latencies similar to those of disynaptic i.p.s.p.s. evoked from group Ia muscle spindle afferents in limb motoneurones. 3. The crossed disynaptic i.p.s.p.s in sacral motoneurones were found to be mediated by interneurones which are themselves inhibited by Renshaw cells, these interneurones and Renshaw cells being activated from the dorsal and ventral roots respectively, on the side of the body opposite to the location of the inhibited motoneurones. 4. In unanaesthetized decerebrate preparations crossed recurrent facilitation of sacral motoneurones was evoked with a time course similar to that of recurrent facilitation of lumbar motoneurones. It was taken to indicate a tonic inhibition of sacral motoneurones by interneurones responsible for their crossed disynaptic inhibition, and a disinhibition following stimulation of contralateral ventral roots. 5. In anaesthetized preparations crossed recurrent inhibition appeared, instead of the recurrent facilitation, in more than one half of the tested motoneurones. 6. A comparison of the input from ipsilateral and contralateral afferents to identified motoneurones of tail muscles with the input to pudendal motoneurones led to the conclusion that crossed disynaptic inhibition is evoked specifically in tail motoneurones. 7. Intracellular staining of sacral motoneurones with horseradish peroxidase revealed that the tail motoneurones and others with crossed disynaptic inhibition differ from the pudendal motoneurones in their location and in a number of morphological features; tail motoneurones are larger, they have differently directed dendrites and they show more extensively branched initial axon collaterals which appeared to ramify only within the ventral and lateral parts of the ipsilateral ventral horn. 8. One Renshaw cell which was stained with horseradish peroxidase was found to project contralaterally, after giving a number of axon collaterals ipsilaterally. PMID:745104

  7. Halenaquinone inhibits RANKL-induced osteoclastogenesis.

    PubMed

    Tsukamoto, Sachiko; Takeuchi, Tomoharu; Kawabata, Tetsuro; Kato, Hikaru; Yamakuma, Michiko; Matsuo, Kanae; El-Desoky, Ahmed H; Losung, Fitje; Mangindaan, Remy E P; de Voogd, Nicole J; Arata, Yoichiro; Yokosawa, Hideyoshi

    2014-11-15

    Halenaquinone was isolated from the marine sponge Petrosia alfiani as an inhibitor of osteoclastogenic differentiation of murine RAW264 cells. It inhibited the RANKL (receptor activator of nuclear factor-?B ligand)-induced upregulation of TRAP (tartrate-resistant acid phosphatase) activity as well as the formation of multinuclear osteoclasts. In addition, halenaquinone substantially suppressed RANKL-induced I?B degradation and Akt phosphorylation. Thus, these results suggest that halenaquinone inhibits RANKL-induced osteoclastogenesis at least by suppressing the NF-?B and Akt signaling pathways. PMID:25278237

  8. Curcumin inhibition of angiogenesis and adipogenesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The growth of new blood vessels or angiogenesis is necessary for the growth of adipose tissue. Adipokines produced by fat cells stimulate this process. Some dietary polyphenols with antiangiogenic activity may suppress adipose tissue growth not only by inhibiting angiogenesis, but also by interferin...

  9. Inhibited interferon production after space flight

    NASA Technical Reports Server (NTRS)

    Sonnenfeld, G.; Gould, C. L.; Williams, J.; Mandel, A. D.

    1988-01-01

    Several studies have been performed in our laboratories indicating that interferon production may be impaired in rodents after space flight. Using an antiorthostatic suspension model that simulates some of the effects of microgravity seen during space flight, we have shown that interferon-alpha/beta production was inhibited. The inhibition was not due solely to the stress of suspension. The inhibited interferon production was transient, as suspended animals returned to normal caging recovered the ability to produce interferon. Antiorthostatic suspension of mice also resulted in a loss of resistance to infection with the diabetogenic strain of encephalomyocarditis virus, which correlated with the drop in interferon production. In rats flown in US Space Shuttle mission SL-3, interferon-gamma production was inhibited severely when spleen cells were challenged with concanavalin-A upon return to earth. In contrast, interleukin-3 production by these cells was normal. These results suggest that immune responses may be altered after antiorthostatic modeling or space flight, and the resistance to viral infections may be especially affected.

  10. Inhibiting Intuitive Thinking in Mathematics Education

    ERIC Educational Resources Information Center

    Thomas, Michael O. J.

    2015-01-01

    The papers in this issue describe recent collaborative research into the role of inhibition of intuitive thinking in mathematics education. This commentary reflects on this research from a mathematics education perspective and draws attention to some of the challenges that arise in collaboration between research fields with different cultures,…

  11. Aromatase Inhibition in a Transcriptional Network Context

    EPA Science Inventory

    A variety of chemicals in the environment have the potential to inhibit aromatase, an enzyme critical to estrogen synthesis. We examined the responses of female fathead minnow ovaries (FHM, Pimephales promelas) to a model aromatase inhibitor, fadrozole, using a transcriptional ne...

  12. The Mechanism Underlying Inhibition of Saccadic Return

    ERIC Educational Resources Information Center

    Ludwig, Casimir J. H.; Farrell, Simon; Ellis, Lucy A.; Gilchrist, Iain D.

    2009-01-01

    Human observers take longer to re-direct gaze to a previously fixated location. Although there has been some exploration of the characteristics of inhibition of saccadic return (ISR), the exact mechanisms by which ISR operates are currently unknown. In the framework of accumulation models of response times, in which evidence is integrated over…

  13. Search Asymmetry, Sustained Attention, and Response Inhibition

    ERIC Educational Resources Information Center

    Stevenson, Hugh; Russell, Paul N.; Helton, William S.

    2011-01-01

    In the present experiment, we used search asymmetry to test whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed feature present and feature absent target detection tasks using either a sustained attention to response task (SART; high Go low No-Go) or a…

  14. Motivational Influences on Response Inhibition Measures

    ERIC Educational Resources Information Center

    Leotti, Lauren A.; Wager, Tor D.

    2010-01-01

    Psychological research has placed great emphasis on inhibitory control due to its integral role in normal cognition and clinical disorders. The stop-signal task and associated measure--stop-signal reaction time (SSRT)--provides a well-established paradigm for measuring response inhibition. However, motivational influences on stop-signal…

  15. Elucidating Influenza Inhibition Pathways via Network Reconstruction

    E-print Network

    Sharan, Roded

    Elucidating Influenza Inhibition Pathways via Network Reconstruction ARNON MAZZA,1 IRIT GAT-VIKS,2 by testing it on the response to influenza infection in humans, with and without the viral inhibitory protein on the influenza A virus, whose NS1 protein is known as an antiviral signaling inhibitor (Gack et al., 2009; Li et

  16. Temporal Preparation, Response Inhibition and Impulsivity

    ERIC Educational Resources Information Center

    Correa, Angel; Trivino, Monica; Perez-Duenas, Carolina; Acosta, Alberto; Lupianez, Juan

    2010-01-01

    Temporal preparation and impulsivity involve overlapping neural structures (prefrontal cortex) and cognitive functions (response inhibition and time perception), however, their interrelations had not been investigated. We studied such interrelations by comparing the performance of groups with low vs. high non-clinical trait impulsivity during a…

  17. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis

    SciTech Connect

    Szkudlarek-Mikho, Maria; Saunders, Rudel A.; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Salinomycin inhibits preadipocyte differentiation into adipocytes. Black-Right-Pointing-Pointer Salinomycin inhibits transcriptional regulation of adipogenesis. Black-Right-Pointing-Pointer Pharmacological effects of salinomycin suggest toxicity in cancer therapy. -- Abstract: The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor {gamma}. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy.

  18. Poliovirus 3C proteinase inhibition by organotelluranes.

    PubMed

    Gouvea, Iuri E; Santos, Jorge A N; Burlandy, Fernanda M; Tersariol, Ivarne L S; da Silva, Edson E; Juliano, Maria A; Juliano, Luiz; Cunha, Rodrigo L O R

    2011-04-01

    The 3C proteinase, essential for human poliovirus (PV) replication, has unique characteristics as its three-dimensional structure resembles chymotrypsin, but its catalytic nucleophile is a cysteine SH group rather than the OH group of serine. Here, we describe the use of tellurium compounds as inhibitors of PV3C proteinase. A rapid, stoichiometric and covalent inactivation of PV3C was observed with both a chloro-telluroxetane and a bis-vinylic organotellurane. These compounds also inhibit human cathepsins B, L, S, and K with second order rate constants higher than those obtained for PV3C. Chloro-telluroxetane inhibits replication of PV in human embryonic rhabdomyosarcoma cells in the low micromolar range and below the toxic level for the host cells. Bis-vinylic organotellurane is more effective as antiviral agent but reduces the cell viability by 20% at 10 ?m, a concentration almost completely inhibiting virus growth. This is the first description of inhibition of viral 3C proteinase with antiviral property by this class of compounds. PMID:21521074

  19. Cyclosporine inhibits macrophage-mediated antigen presentation

    SciTech Connect

    Ziegler, H.K.; Palay, D.; Wentworth, P.; Cluff, C.

    1986-03-01

    The influence of cyclosporine on antigen-specific, macrophage-dependent T cell activation was analyzed in vitro. Murine T cell activation by antigens derived from Listeria monocytogenes was monitored by the production of interleukin-2. Pretreatment (2 hrs., 37/sup 0/C) of macrophages with cyclosporine resulted in a population of macrophages with a markedly diminished capacity to support the activation of T lymphocytes. When cyclosporine-pretreated macrophages were added to cultures of antigen and untreated T cells, the dose of cyclosporine which produced 50% inhibition was 1.5 ..mu..g/ml. Appropriate control experiments indicated that cyclosporine was indeed inhibiting at the macrophage level. The addition of interleukin-1 or indomethacin to the cultures did not alter the inhibitory effect of cyclosporine. Under conditions which produced >90% inhibition of antigen presentation, macrophage surface Ia expression was not altered, and the uptake and catabolism of radiolabelled antigen was normal. Thus, cyclosporine inhibits antigen presentation by a mechanism which appears unrelated to changes in Il-1 elaboration, prostaglandin production, Ia expression, or antigen uptake and catabolism.

  20. Hemagglutinin inhibition assay with swine sera

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hemagglutination is based on the ability of certain viruses to agglutinate red blood cells (RBC) of certain animal species by formation of cross-linking lattices between RBC. Antibodies that have the ability to inhibit the hemagglutination property of influenza A viruses are generally thought to pro...

  1. Product Inhibition in Native-State Proteolysis

    PubMed Central

    Kasper, Joseph R.; Andrews, Elizabeth C.; Park, Chiwook

    2014-01-01

    The proteolysis kinetics of intact proteins by nonspecific proteases provides valuable information on transient partial unfolding of proteins under native conditions. Native-state proteolysis is an approach to utilize the proteolysis kinetics to assess the energetics of partial unfolding in a quantitative manner. In native-state proteolysis, folded proteins are incubated with nonspecific proteases, and the rate of proteolysis is determined from the disappearance of the intact protein. We report here that proteolysis of intact proteins by nonspecific proteases, thermolysin and subtilisin deviates from first-order kinetics. First-order kinetics has been assumed for the analysis of native-state proteolysis. By analyzing the kinetics of proteolysis with varying concentrations of substrate proteins and also with cleavage products, we found that the deviation from first-order kinetics results from product inhibition. A kinetic model including competitive product inhibition agrees well with the proteolysis time course and allows us to determine the uninhibited rate constant for proteolysis as well as the apparent inhibition constant. Our finding suggests that the likelihood of product inhibition must be considered for quantitative assessment of proteolysis kinetics. PMID:25360755

  2. Inhibition of Ultrasonic Vocalizations by Beta-

    E-print Network

    Inhibition of Ultrasonic Vocalizations by Beta- Adrenoceptor Agonists Mark S. Blumberg Eric D-mail: mark-blumberg@uiowa.edu ABSTRACT: Infant rat ultrasonic vocalizations (USVs) are widely believed The ultrasonic vocalization (USV) of infant rats has been variously interpreted as a signal of the emotional

  3. Target Predictability, Sustained Attention, and Response Inhibition

    ERIC Educational Resources Information Center

    Carter, Leonie; Russell, Paul N.; Helton, William S.

    2013-01-01

    We examined whether the sustained attention to response task is a better measure of response inhibition or sustained attention. Participants performed a number detection task for 37.3 min using either a Sustained Attention to Response Task (SART; high Go low No-Go) or a more traditionally formatted vigilance task (TFT; high No-Go low Go) response…

  4. Behavioral Inhibition in Children with Learning Disabilities

    ERIC Educational Resources Information Center

    De Weerdt, Frauke; Desoete, Annemie; Roeyers, Herbert

    2013-01-01

    Children with reading disabilities (RD, n = 17), mathematical disabilities (MD, n = 22), combined reading and mathematical disabilities (RD + MD, n = 28) and control peers (n = 45) were tested on behavioral inhibition with a Go/no-go task in a picture, letter and digit-modality. In contrast to children without RD, children with RD made…

  5. BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL TROPHOBLAST DIFFERENTIATION

    EPA Science Inventory

    BROMODICHLOROMETHANE INHIBITS HUMAN PLACENTAL
    TROPHOBLAST DIFFERENTIATION
    Jiangang Chen, Twanda L. Thirkill, Peter N. Lohstroh, Susan R. Bielmeier, Michael
    G. Narotsky, Deborah S. Best, Randy A. Harrison, Kala Natarajan, Rex A. Pegram,
    Bill L. Lasley, and Gordon C. Do...

  6. COMMUNICATION Inhibition of Mammalian Glycan Biosynthesis Produces

    E-print Network

    design. Here, we show that chemical inhibition of mammalian glycoprotein synthesis, with the plant/non-self discrimination between viral and host glycans, by a neutralising antibody. Moreover, this study provides an alternative protein engineering approach to the design of a carbohydrate vaccine for HIV-1 by chemical

  7. Illustrating Enzyme Inhibition Using Gibbs Energy Profiles

    ERIC Educational Resources Information Center

    Bearne, Stephen L.

    2012-01-01

    Gibbs energy profiles have great utility as teaching and learning tools because they present students with a visual representation of the energy changes that occur during enzyme catalysis. Unfortunately, most textbooks divorce discussions of traditional kinetic topics, such as enzyme inhibition, from discussions of these same topics in terms of…

  8. TRIMETHYLTIN REDUCES RECURRENT INHIBITION IN RATS

    EPA Science Inventory

    Rats with electrodes chronically implanted in the perforant path for electrical stimulation, and dentate gyrus for recording were treated with a single oral administration of either saline, 5 mg/kg trimethyltin (TMT) or 6 mg/kg TMT. Recurrent inhibition was assessed by paired pul...

  9. Inhibition of denitrification by ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Mancinelli, R. L.; White, M. R.

    It has been shown that UV-A (? = 320- 400 nm) and UV-B (? = 280 - 320 nm) inhibit photosynthesis, nitrogen fixation and nitrification. The purpose of this study was to determine the effects, if any, on denitrification in a microbial community inhabiting the intertidal. The community studied is the microbial mat consisting primarily of Lyngbya that inhabits the Pacific marine intertidal, Baja California, Mexico. Rates of denitrification were determined using the acetylene blockage technique. Pseudomonas fluorescens (ATCC # 17400) was used as a control organism, and treated similarly to the mat samples. Samples were incubated either beneath a PAR transparent, UV opaque screen (OP3), or a mylar screen to block UV-B, or a UV transparent screen (UVT) for 2 to 3 hours. Sets of samples were also treated with nitrapyrin to inhibit nitrification, or DCMU to inhibit photosynthesis and treated similarly. Denitrification rates were greater in the UV protected samples than in the UV exposed samples the mat samples as well as for the Ps. fluorescens cultures. Killed controls exhibited no activity. In the DCMU and nitrapyrin treated samples denitrification rates were the same as in the untreated samples. These data indicate that denitrification is directly inhibited by UV radiation.

  10. Nitrite inhibition of denitrification by Pseudomonas fluorescens

    SciTech Connect

    Almeida, J.S.; Julio, S.M.; Reis, M.A.M. |

    1995-05-05

    Using a pure culture of Pseudomonas fluorescens as a model system nitrite inhibition of denitrification was studied. A mineral media with acetate and nitrate as sole electron donor and acceptor, respectively, was used. Results obtained in continuous stirred-tank reactors (CSTR) operated at pH values between 6.6 and 7.8 showed that growth inhibition depended only on the nitrite undissociated fraction concentration (nitrous acid). A mathematical model to describe this dependence is put forward. The maximum nitrous acid concentration compatible with cell growth and denitrification activity was found to be 66 {mu}g N/L. Denitrification activity was partially associated with growth, as described by the Luedeking-Piret equation. However, when the freshly inoculated reactor was operated discontinuously, nitrite accumulation caused growth uncoupling from denitrification activity. The authors suggest that these results can be interpreted considering that (a) nitrous acid acts as a proton uncoupler; and (b) cultures continuously exposed to nitrous acid prevent the uncoupling effect but not the growth inhibition. Examination of the growth dependence on nitrite concentration at pH 7.0 showed that adapted cultures (growth on CSTR) are less sensitive to nitrous acid inhibition than the ones cultivated in batch.

  11. Nickel inhibits mitochondrial fatty acid oxidation.

    PubMed

    Uppala, Radha; McKinney, Richard W; Brant, Kelly A; Fabisiak, James P; Goetzman, Eric S

    2015-08-01

    Nickel exposure is associated with changes in cellular energy metabolism which may contribute to its carcinogenic properties. Here, we demonstrate that nickel strongly represses mitochondrial fatty acid oxidation-the pathway by which fatty acids are catabolized for energy-in both primary human lung fibroblasts and mouse embryonic fibroblasts. At the concentrations used, nickel suppresses fatty acid oxidation without globally suppressing mitochondrial function as evidenced by increased glucose oxidation to CO2. Pre-treatment with l-carnitine, previously shown to prevent nickel-induced mitochondrial dysfunction in neuroblastoma cells, did not prevent the inhibition of fatty acid oxidation. The effect of nickel on fatty acid oxidation occurred only with prolonged exposure (>5 h), suggesting that direct inhibition of the active sites of metabolic enzymes is not the mechanism of action. Nickel is a known hypoxia-mimetic that activates hypoxia inducible factor-1? (HIF1?). Nickel-induced inhibition of fatty acid oxidation was blunted in HIF1? knockout fibroblasts, implicating HIF1? as one contributor to the mechanism. Additionally, nickel down-regulated the protein levels of the key fatty acid oxidation enzyme very long-chain acyl-CoA dehydrogenase (VLCAD) in a dose-dependent fashion. In conclusion, inhibition of fatty acid oxidation by nickel, concurrent with increased glucose metabolism, represents a form of metabolic reprogramming that may contribute to nickel-induced carcinogenesis. PMID:26051273

  12. MFR PAPER 1339 Phosphonoacetic Acid Inhibition of

    E-print Network

    MFR PAPER 1339 Phosphonoacetic Acid Inhibition of Channel Catfish Virus Replication Roger W. Koment The virus responsible for epizootic outbreaks of channel catfish disease was first isolated by Fijan et al and Darlington (197 [) clearly indicated the assignment of channel catfish virus (CCY) to the her- pesvirus group

  13. Gold Nanoparticles Inhibit Matrix Metalloproteases without Cytotoxicity.

    PubMed

    Hashimoto, M; Sasaki, J I; Yamaguchi, S; Kawai, K; Kawakami, H; Iwasaki, Y; Imazato, S

    2015-08-01

    Nanoparticles (NPs) are currently the focus of considerable attention for dental applications; however, their biological effects have not been fully elucidated. The long-term, slow release of matrix metalloproteases (MMPs) digests collagen fibrils within resin-dentin bonds. Therefore, MMP inhibitors can prolong the durability of resin-dentin bonds. However, there have been few reports evaluating the combined effect of MMP inhibition and the cytotoxic effects of NPs for dentin bonding. The aim of this study was to evaluate MMP inhibition and cytotoxic responses to gold (AuNPs) and platinum nanoparticles (PtNPs) stabilized by polyvinylpyrrolidone (PVP) in cultured murine macrophages (RAW264) by using MMP inhibition assays, measuring cell viability and inflammatory responses (quantitative reverse transcription polymerase chain reaction [RT-qPCR]), and conducting a micromorphological analysis by fluorescence and transmission electron microscopy. Cultured RAW264 cells were exposed to metal NPs at various concentrations (1, 10, 100, and 400 µg/mL). AuNPs and PtNPs markedly inhibited MMP-8 and MMP-9 activity. Although PtNPs were cytotoxic at high concentrations (100 and 400 µg/mL), no cytotoxic effects were observed for AuNPs at any concentration. Transmission electron microscopy images showed a significant nonrandom intercellular distribution for AuNPs and PtNPs, which were mostly observed to be localized in lysosomes but not in the nucleus. RT-qPCR analysis demonstrated inflammatory responses were not induced in RAW264 cells by AuNPs or PtNPs. The cytotoxicity of nanoparticles might depend on the core metal composition and arise from a "Trojan horse" effect; thus, MMP inhibition could be attributed to the surface charge of PVP, which forms the outer coating of NPs. The negative charge of the surface coating of PVP binds to Zn(2+) from the active center of MMPs by chelate binding and results in MMP inhibition. In summary, AuNPs are attractive NPs that effectively inhibit MMP activity without cytotoxicity or inflammatory responses. PMID:26040283

  14. Collaborative inhibition in spatial memory retrieval.

    PubMed

    Sjolund, Lori A; Erdman, Matthew; Kelly, Jonathan W

    2014-08-01

    Collaborative inhibition refers to the finding that pairs of people working together to retrieve information from memory-a collaborative group-often retrieve fewer unique items than do nominal pairs, who retrieve individually but whose performance is pooled. Two experiments were designed to explore whether collaborative inhibition, which has heretofore been studied using traditional memory stimuli such as word lists, also characterizes spatial memory retrieval. In the present study, participants learned a layout of objects and then reconstructed the layout from memory, either individually or in pairs. The layouts created by collaborative pairs were more accurate than those created by individuals, but less accurate than those of nominal pairs, providing evidence for collaborative inhibition in spatial memory retrieval. Collaborative inhibition occurred when participants were allowed to dictate the order of object placement during reconstruction (Exp. 1), and also when object order was imposed by the experimenter (Exp. 2), which was intended to disrupt the retrieval processes of pairs as well as of individuals. Individual tests of perspective taking indicated that the underlying representations of pair members were no different than those of individuals; in all cases, spatial memories were organized around a reference frame aligned with the studied perspective. These results suggest that inhibition is caused by the product of group recall (i.e., seeing a partner's object placement), not by the process of group recall (i.e., taking turns choosing an object to place). The present study has implications for how group performance on a collaborative spatial memory task may be optimized. PMID:24622929

  15. VISUALIZATION-BASED ANALYSIS FOR A MIXED-INHIBITION BINARY PBPK MODEL: DETERMINATION OF INHIBITION MECHANISM

    EPA Science Inventory

    A physiologically-based pharmacokinetic (PBPK) model incorporating mixed enzyme inhibition was used to determine mechanism of the metabolic interactions occurring during simultaneous inhalation exposures to the organic solvents chloroform and trichloroethylene (TCE).

    V...

  16. Inhibition of topoisomerase 2 does not inhibit transcription of RNA polymerase 1 and 2 genes

    SciTech Connect

    Dunaway, M. )

    1990-06-01

    Injection of VM-26 (teniposide) into {ital Xenopus} oocytes inhibits the activity of topoisomerase II but does not inhibit transcription by RNA polymerases I and II. A specific assay for topoisomerase II, resolution of catenated DNA molecules into product rings, was used to quantitate VM-26 inhibition in vivo. When catenanes were injected without VM-26, about 60% of them were separated into product rings in the first 5 min after injection, and decatenation of the remainder was complete within 15 min. When VM-26 was coinjected, 60% of the catenanes were separated into product rings in the first 5 min after injection, but the remaining 40% were stable over the next 40 min. At 1 h after injection catenanes were no longer detected in the gel analysis, but the increasing numbers of linear product rings indicated that topoisomerase II continued to be inhibited by VM-26. These results suggest that a short lag of approximately 5 min is required for VM-26 to inhibit topoisomerase II and that after this initial period topoisomerase II is inhibited by more than 90%.

  17. Crocetinic acid inhibits hedgehog signaling to inhibit pancreatic cancer stem cells.

    PubMed

    Rangarajan, Parthasarathy; Subramaniam, Dharmalingam; Paul, Santanu; Kwatra, Deep; Palaniyandi, Kanagaraj; Islam, Shamima; Harihar, Sitaram; Ramalingam, Satish; Gutheil, William; Putty, Sandeep; Pradhan, Rohan; Padhye, Subhash; Welch, Danny R; Anant, Shrikant; Dhar, Animesh

    2015-09-29

    Pancreatic cancer is the fourth leading cause of cancer deaths in the US and no significant treatment is currently available. Here, we describe the effect of crocetinic acid, which we purified from commercial saffron compound crocetin using high performance liquid chromatography. Crocetinic acid inhibits proliferation of pancreatic cancer cell lines in a dose- and time-dependent manner. In addition, it induced apoptosis. Moreover, the compound significantly inhibited epidermal growth factor receptor and Akt phosphorylation. Furthermore, crocetinic acid decreased the number and size of the pancospheres in a dose-dependent manner, and suppressed the expression of the marker protein DCLK-1 (Doublecortin Calcium/Calmodulin-Dependent Kinase-1) suggesting that crocetinic acid targets cancer stem cells (CSC). To understand the mechanism of CSC inhibition, the signaling pathways affected by purified crocetinic acid were dissected. Sonic hedgehog (Shh) upon binding to its cognate receptor patched, allows smoothened to accumulate and activate Gli transcription factor. Crocetinic acid inhibited the expression of both Shh and smoothened. Finally, these data were confirmed in vivo where the compound at a dose of 0.5 mg/Kg bw suppressed growth of tumor xenografts. Collectively, these data suggest that purified crocetinic acid inhibits pancreatic CSC, thereby inhibiting pancreatic tumorigenesis. PMID:26317547

  18. Wogonin inhibits osteoclast differentiation by inhibiting NFATc1 translocation into the nucleus

    PubMed Central

    GENG, XIAOLIN; YANG, LIBIN; ZHANG, CHAO; QIN, HUA; LIANG, QIUDONG

    2015-01-01

    The aim of the present study was to identify a natural product with the ability to inhibit nuclear factor of activated T cells c1 (NFATc1) translocation from the cytoplasm to the nucleus by high-throughput screening, and to investigate the effect of the natural product upon osteoclast differentiation and its underlying mechanism. An NFATc1 antagonist redistribution assay was performed in U2OS-NFATc1 cells against a natural product library, and Wogonin was found to have the ability to inhibit the NFATc1 translocation from the cytoplasm to the nucleus. The effect of Wogonin on NFATc1 transcription activation was further determined by luciferase assay. An osteoclast differentiation assay was executed to evaluate the effect of Wogonin on osteoclast differentiation. The effect of Wogonin upon the vital genes in osteoclast differentiation was investigated using fluorescent quantitative polymerase chain reaction analysis. The natural product Wogonin significantly inhibited the translocation of NFATc1 from the cytoplasm to the nucleus and its transcriptional activation activity. Wogonin also significantly inhibited osteoclast differentiation and decreased the transcription of osteoclast-associated immunoglobulin-like receptor, tartrate-resistant acid phosphatase and calcitonin receptor. In conclusion, the natural product Wogonin inhibited osteoclast differentiation through the inhibition of NFATc1 translocation from the cytoplasm to the nucleus, and thus the downregulation of genes associated with osteoclast differentiation, which marked Wogonin as a potential treatment for osteoporosis.

  19. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  20. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  1. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  2. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  3. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Vinyl chloride: Inhibiting and inerting. 154...Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that:...

  4. Ptilomycalin A inhibits laccase and melanization in Cryptococcus neoformans

    PubMed Central

    Dalisay, Doralyn S.; Saludes, Jonel P.; Molinski, Tadeusz F.

    2011-01-01

    The antifungal spirocyclic guanidine alkaloid, ptilomycalin A, from marine sponge Monanchora arbuscula, inhibits melanogenesis of Cryptococcus neoformans in vitro through inhibition of biosynthesis of laccase in the melanin biosynthetic pathway with an IC50 of 7. 3 ?M. PMID:21715177

  5. Hydrochlorothiazide inhibits osteoclastic bone resorption in vitro.

    PubMed

    Hall, T J; Schaueblin, M

    1994-10-01

    Long-term thiazide diuretic use is associated with higher bone mineral density and reduced hip fracture rates, which are attributed to increased serum calcium levels and decreased parathyroid activity that lead to decreased bone resorption. The present study shows that 1-100 microM hydrochlorothiazide (HCTZ) dose dependently inhibits bone resorption by isolated rat osteoclasts in the bone slice assay with an IC50 of approximately 20 microM. At these concentrations, HCTZ did not affect osteoclast survival on bone slices and had no effect on the proliferation of UMR-106 rat osteoblasts, indicating that the compound is not cytotoxic. However, such concentrations of HCTZ are unlikely to be achieved in man where therapeutic doses are usually 12.5-100 mg/day. That the in vitro effect of HCTZ on bone resorption may be due to inhibition of osteoclast carbonic anhydrase is discussed. PMID:7820777

  6. Allosteric Inhibition of the Neuropeptidase Neurolysin*

    PubMed Central

    Hines, Christina S.; Ray, Kallol; Schmidt, Jack J.; Xiong, Fei; Feenstra, Rolf W.; Pras-Raves, Mia; de Moes, Jan Peter; Lange, Jos H. M.; Melikishvili, Manana; Fried, Michael G.; Mortenson, Paul; Charlton, Michael; Patel, Yogendra; Courtney, Stephen M.; Kruse, Chris G.; Rodgers, David W.

    2014-01-01

    Neuropeptidases specialize in the hydrolysis of the small bioactive peptides that play a variety of signaling roles in the nervous and endocrine systems. One neuropeptidase, neurolysin, helps control the levels of the dopaminergic circuit modulator neurotensin and is a member of a fold group that includes the antihypertensive target angiotensin converting enzyme. We report the discovery of a potent inhibitor that, unexpectedly, binds away from the enzyme catalytic site. The location of the bound inhibitor suggests it disrupts activity by preventing a hinge-like motion associated with substrate binding and catalysis. In support of this model, the inhibition kinetics are mixed, with both noncompetitive and competitive components, and fluorescence polarization shows directly that the inhibitor reverses a substrate-associated conformational change. This new type of inhibition may have widespread utility in targeting neuropeptidases. PMID:25378390

  7. AMPK inhibition in health and disease

    PubMed Central

    Viollet, Benoit; Horman, Sandrine; Leclerc, Jocelyne; Lantier, Louise; Foretz, Marc; Billaud, Marc; Giri, Shailendra; Andreelli, Fabrizio

    2010-01-01

    All living organisms depend on dynamic mechanisms that repeatedly reassess the status of amassed energy, in order to adapt energy supply to demand. The AMP-activated protein kinase (AMPK) ??? heterotrimer has emerged as an important integrator of signals managing energy balance. Control of AMPK activity involves allosteric AMP and ATP regulation, auto-inhibitory features and phosphorylation of its catalytic (?) and regulatory (? and ?) subunits. AMPK has a prominent role not only as a peripheral sensor but also in the central nervous system as a multifunctional metabolic regulator. AMPK represents an ideal second messenger for reporting cellular energy state. For this reason, activated AMPK acts as a protective response to energy stress in numerous systems. However, AMPK inhibition also actively participates in the control of whole body energy homeostasis. In this review, we discuss recent findings that support the role and function of AMPK inhibition under physiological and pathological states. PMID:20522000

  8. Preventing MIC through microbial adhesion inhibition

    SciTech Connect

    Videla, H.A.; Guiamet, P.S.; Gomez de Saravia, S.G.

    1998-12-31

    The key to the alteration of conditions at a metal surface before the initiation of microbially induced corrosion (MIC) is the formation of a biofilm. Thus, prevention of bacterial adhesion processes on metal surfaces would be one of the potential weapons to avoid MIC. Serum globulin and by-products were used to prevent bacterial adhesion on different corrosion resistant metal surfaces generally used as implantable biomaterials. In this paper an immunoglobulin combination (IgA, IgG and IgM) has been used to prevent the formation of Pseudomonas fluorescens (P.fluorescens) biofilms on carbon steel and two different types of stainless steel (SS). A marked inhibition of bacterial adhesion was found under different experimental conditions. Several microscopic techniques were used for assessing adhesion inhibition while the electrochemical behavior of the steels was evaluated by means of different electrochemical techniques applied in the presence and in the absence of the immunoglobulins.

  9. Role of inhibition in respiratory pattern generation.

    PubMed

    Janczewski, Wiktor A; Tashima, Alexis; Hsu, Paul; Cui, Yan; Feldman, Jack L

    2013-03-27

    Postsynaptic inhibition is a key element of neural circuits underlying behavior, with 20-50% of all mammalian (nongranule) neurons considered inhibitory. For rhythmic movements in mammals, e.g., walking, swimming, suckling, chewing, and breathing, inhibition is often hypothesized to play an essential rhythmogenic role. Here we study the role of fast synaptic inhibitory neurotransmission in the generation of breathing pattern by blocking GABA(A) and glycine receptors in the preBötzinger complex (preBötC), a site essential for generation of normal breathing pattern, and in the neighboring Bötzinger complex (BötC). The breathing rhythm continued following this blockade, but the lung inflation-induced Breuer-Hering inspiratory inhibitory reflex was suppressed. The antagonists were efficacious, as this blockade abolished the profound effects of the exogenously applied GABA(A) receptor agonist muscimol or glycine, either of which under control conditions stopped breathing in vagus-intact or vagotomized, anesthetized, spontaneously breathing adult rats. In vagotomized rats, GABA(A)ergic and glycinergic antagonists had little, if any, effect on rhythm. The effect in vagus-intact rats was to slow the rhythm to a pace equivalent to that seen after suppression of the aforementioned Breuer-Hering inflation reflex. We conclude that postsynaptic inhibition within the preBötC and BötC is not essential for generation of normal respiratory rhythm in intact mammals. We suggest the primary role of inhibition is in shaping the pattern of respiratory motor output, assuring its stability, and in mediating reflex or volitional apnea, but not in the generation of rhythm per se. PMID:23536061

  10. The WAVE Regulatory Complex is Inhibited

    PubMed Central

    Ismail, Ayman M.; Padrick, Shae B.; Chen, Baoyu; Umetani, Junko; Rosen, Michael K.

    2009-01-01

    The WAVE Regulatory Complex (WRC) transmits information from the Rac GTPase to the actin nucleator, Arp2/3 complex. We have reconstituted recombinant human and Drosophila WRC in several forms and shown that they are inactive toward Arp2/3 complex, but can be activated by Rac in nucleotide dependent fashion. Our observations identify core components needed for WAVE inhibition, reconcile contradictory existing mechanisms and reveal common regulatory principles for the WAVE/WASP family. PMID:19363480

  11. Inhibiting the Function of an Enzyme

    SciTech Connect

    2015-06-17

    In order to stop bacteria from reproducing and causing a disease like tuberculosis, researchers must first block its enzymes' ability to bind with certain molecules. A research team from Brandeis University worked with the Advanced Protein Characterization Facility at Argonne National Laboratory to define 13 different bacterial structures and uncover the mechanism by which their enzymes form and break bonds with molecules. This animation depicts how an enzyme may be inhibited using this knowledge.

  12. Chondroitin sulphate inhibits connective tissue mast cells.

    PubMed

    Theoharides, T C; Patra, P; Boucher, W; Letourneau, R; Kempuraj, D; Chiang, G; Jeudy, S; Hesse, L; Athanasiou, A

    2000-11-01

    1. Mast cells derive from the bone marrow and are responsible for the development of allergic and possibly inflammatory reactions. Mast cells are stimulated by immunoglobulin E (IgE) and specific antigen, but also by a number of neuropeptides such as neurotensin (NT), somatostatin or substance P (SP), to secrete numerous pro-inflammatory molecules that include histamine, cytokines and proteolytic enzymes. 2. Chondroitin sulphate, a major constituent of connective tissues and of mast cell secretory granules, had a dose-dependent inhibitory effect on rat peritoneal mast cell release of histamine induced by the mast cell secretagogue compound 48/80 (48/80). This inhibition was stronger than that of the clinically available mast cell 'stabilizer' disodium cromoglycate (cromolyn). Inhibition by chondroitin sulphate increased with the length of preincubation and persisted after the drug was washed off, while the effect of cromolyn was limited by rapid tachyphylaxis. 3. Immunologic stimulation of histamine secretion from rat connective tissue mast cells (CTMC) was also inhibited, but this effect was weaker in umbilical cord-derived human mast cells and was absent in rat basophilic leukemia (RBL) cells which are considered homologous to mucosal mast cells (MMC). Oligo- and monosaccharides were not as effective as the polysaccharides. 4. Inhibition, documented by light and electron microscopy, involved a decrease of intracellular calcium ion levels shown by confocal microscopy and image analysis. Autoradiography at the ultrastructural level showed that chondroitin sulphate was mostly associated with plasma and perigranular membranes. 5. Chondroitin sulphate appears to be a potent mast cell inhibitor of allergic and nonimmune stimulation with potential clinical implications. PMID:11082109

  13. ROLE OF INHIBITION IN RESPIRATORY PATTERN GENERATION

    PubMed Central

    Janczewski, Wiktor A.; Tashima, Alexis; Hsu, Paul; Cui, Yan; Feldman, Jack L.

    2013-01-01

    Postsynaptic inhibition is a key element of neural circuits underlying behavior, with 20-50% of all mammalian (non-granule) neurons considered inhibitory. For rhythmic movements in mammals, e.g., walking, swimming, suckling, chewing, breathing, inhibition is often hypothesized to play an essential rhythmogenic role. Here we study the role of fast synaptic inhibitory neurotransmission in the generation of breathing pattern by blocking GABAA and glycine receptors in the preBötzinger Complex (preBötC), a site essential for generation of normal breathing pattern, and in the neighboring Bötzinger Complex (BötC). The breathing rhythm continued following this blockade, but the lung inflation-induced Breuer-Hering inspiratory-inhibitory reflex was suppressed. The antagonists were efficacious, as this blockade abolished the profound effects of the exogenously applied GABAA receptor agonist muscimol or glycine, either of which under control conditions stopped breathing in vagus-intact or vagotomized, anesthetized, spontaneously breathing adult rats. In vagotomized rats, GABAAergic and glycinergic antagonists had little, if any, effect on rhythm. The effect in vagus intact rats was to slow the rhythm to a pace equivalent to that seen after suppression of the aforementioned Breuer-Hering inflation reflex. We conclude that postsynaptic inhibition within the preBötC and BötC is not essential for generation of normal respiratory rhythm in intact mammals. We suggest the primary role of inhibition is in shaping the pattern of respiratory motor output, assuring its stability, and in mediating reflex or volitional apnea, but not in the generation of rhythm per se. PMID:23536061

  14. Inhibition of tyrosinase by protocatechuic aldehyde.

    PubMed

    No, Jae Kyung; Kim, Min Sun; Kim, You Jung; Bae, Song Ja; Choi, Jae Sue; Chung, Hae Young

    2004-01-01

    The purpose of this study was to determine the inhibitory action of protocatechuic aldehyde (PCA) on tyrosinase activity. PCA is one of the compounds found in the root of Salvia miltiorrhiza. Our study documented that PCA has a potent inhibitory effect on tyrosinase, which catalyzes the rate-limiting step of melanin biosynthesis. Although melanin biosynthesis has an essential function normally in human skin for defense against ultraviolet light of the sun, its abnormal activity as seen in pigmentation disorder could lead to serious medical problems. Our data showed that PCA, with concentrations ranging from 1 x 10(-5) M to 8 x 10(-5) M, exhibited dose-dependent inhibition of the enzyme activity with 50% of inhibition at 19.92 x 10(-6) M. A further kinetic analysis on PCA inactivation of tyrosinase activity revealed a competitive inhibition of the enzyme at the L-tyrosine binding site. The findings of our present study merit further research on the applicability of PCA as a potential agent for treatment of pigmentation disorder. PMID:15154289

  15. JAK INHIBITION AND PROGRESSIVE KIDNEY DISEASE

    PubMed Central

    Brosius, Frank C.; He, John Cijiang

    2015-01-01

    Purpose of review To review the role of JAK-STAT signaling in the progression of chronic kidney diseases. Recent findings The JAK-STAT pathway transmits signals from extracellular ligands, including many cytokines and chemokines. While these responses are best characterized in lymphoid cells, they also occur in kidney cells such as podocytes, mesangial cells, and tubular cells. JAK-STAT expression and signaling abnormalities occur in humans and animal models of different chronic kidney diseases. Enhanced expression and augmented activity of JAK1, JAK2 and STAT3 promote diabetic nephropathy and their inhibition appears to reduce disease. Activation of JAK-STAT signaling in autosomal dominant polycystic kidney disease may play an important role in cyst growth. Activation of JAK-STAT signaling promotes HIV-associated nephropathy and may also participate in the tubular responses to chronic obstructive uropathy. Based on data from experimental models, inhibition of JAK-STAT signaling, via increased expression of the suppressors of cytokine signaling proteins or pharmacologic inhibition of JAK and STAT proteins, could play a therapeutic role in multiple chronic kidney diseases. Summary Activation of the JAK-STAT pathway appears to play a role in the progression of some chronic kidney diseases. More work is needed to determine the specific role the pathway plays in individual diseases. PMID:25415616

  16. Antipneumococcal activity of neuraminidase inhibiting artocarpin.

    PubMed

    Walther, E; Richter, M; Xu, Z; Kramer, C; von Grafenstein, S; Kirchmair, J; Grienke, U; Rollinger, J M; Liedl, K R; Slevogt, H; Sauerbrei, A; Saluz, H P; Pfister, W; Schmidtke, M

    2015-05-01

    Streptococcus (S.) pneumoniae is a major cause of secondary bacterial pneumonia during influenza epidemics. Neuraminidase (NA) is a virulence factor of both pneumococci and influenza viruses. Bacterial neuraminidases (NAs) are structurally related to viral NA and susceptible to oseltamivir, an inhibitor designed to target viral NA. This prompted us to evaluate the antipneumococcal potential of two NA inhibiting natural compounds, the diarylheptanoid katsumadain A and the isoprenylated flavone artocarpin. Chemiluminescence, fluorescence-, and hemagglutination-based enzyme assays were applied to determine the inhibitory efficiency (IC(50) value) of the tested compounds towards pneumococcal NAs. The mechanism of inhibition was studied via enzyme kinetics with recombinant NanA NA. Unlike oseltamivir, which competes with the natural substrate of NA, artocarpin exhibits a mixed-type inhibition with a Ki value of 9.70 ?M. Remarkably, artocarpin was the only NA inhibitor (NAI) for which an inhibitory effect on pneumococcal growth (MIC: 0.99-5.75 ?M) and biofilm formation (MBIC: 1.15-2.97 ?M) was observable. In addition, we discovered that the bactericidal effect of artocarpin can reduce the viability of pneumococci by a factor of >1000, without obvious harm to lung epithelial cells. This renders artocarpin a promising natural product for further investigations. PMID:25592264

  17. Spatholobus suberectus inhibits osteoclastogenesis and stimulates chondrogenesis.

    PubMed

    Im, Nam-Kyung; Lee, Sung-Gyu; Lee, Dong-Sung; Park, Pil-Hoon; Lee, In-Seon; Jeong, Gil-Saeng

    2014-01-01

    This study was carried out to investigate the effect of Spatholobus suberectus Dunn (SS) on the protection of chondral defect and inhibition of osteoclastogenesis. To examine these effects, we measured the matrix metalloproteinase (MMP) levels in SW1353 chondrosarcoma cells and performed tartrate-resistant acid phosphatase (TRAP) staining in bone marrow macrophage (BMM)-derived osteoclasts. To investigate the anti-osteoarthritis (OA) effects, we assessed TNF-?-induced MMP-1, -3, -9 and tissue inhibitors of matrix metalloproteinase (TIMP) expression levels in SW1353 cells. We observed that SS extract significantly inhibited MMP and TIMP expression in SW1353 cells. Also, SS extract inhibited the receptor activator of nuclear factor-?B ligand (RANKL)-induced osteoclast differentiation. These results suggest that SS extract may have a potential in the treatment of bone loss and chondral defect by suppressing osteoclast differentiation and decreasing the expression of OA factors. Therefore, clarification of the mechanism of the action of SS extract and its active components is needed. PMID:25242079

  18. Pharmacological Inhibition of Feline Immunodeficiency Virus (FIV)

    PubMed Central

    Mohammadi, Hakimeh; Bienzle, Dorothee

    2012-01-01

    Feline immunodeficiency virus (FIV) is a member of the retroviridae family of viruses and causes an acquired immunodeficiency syndrome (AIDS) in domestic and non-domestic cats worldwide. Genome organization of FIV and clinical characteristics of the disease caused by the virus are similar to those of human immunodeficiency virus (HIV). Both viruses infect T lymphocytes, monocytes and macrophages, and their replication cycle in infected cells is analogous. Due to marked similarity in genomic organization, virus structure, virus replication and disease pathogenesis of FIV and HIV, infection of cats with FIV is a useful tool to study and develop novel drugs and vaccines for HIV. Anti-retroviral drugs studied extensively in HIV infection have targeted different steps of the virus replication cycle: (1) inhibition of virus entry into susceptible cells at the level of attachment to host cell surface receptors and co-receptors; (2) inhibition of fusion of the virus membrane with the cell membrane; (3) blockade of reverse transcription of viral genomic RNA; (4) interruption of nuclear translocation and viral DNA integration into host genomes; (5) prevention of viral transcript processing and nuclear export; and (6) inhibition of virion assembly and maturation. Despite much success of anti-retroviral therapy slowing disease progression in people, similar therapy has not been thoroughly investigated in cats. In this article we review current pharmacological approaches and novel targets for anti-lentiviral therapy, and critically assess potentially suitable applications against FIV infection in cats. PMID:22754645

  19. Inhibition of enveloped viruses infectivity by curcumin.

    PubMed

    Chen, Tzu-Yen; Chen, Da-Yuan; Wen, Hsiao-Wei; Ou, Jun-Lin; Chiou, Shyan-Song; Chen, Jo-Mei; Wong, Min-Liang; Hsu, Wei-Li

    2013-01-01

    Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA) activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB)-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter) than for the pseudorabies virus (approximately 180 nm) and the vaccinia virus (roughly 335 × 200 × 200 nm). These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses. PMID:23658730

  20. Inhibition of Enveloped Viruses Infectivity by Curcumin

    PubMed Central

    Wen, Hsiao-Wei; Ou, Jun-Lin; Chiou, Shyan-Song; Chen, Jo-Mei; Wong, Min-Liang; Hsu, Wei-Li

    2013-01-01

    Curcumin, a natural compound and ingredient in curry, has antiinflammatory, antioxidant, and anticarcinogenic properties. Previously, we reported that curcumin abrogated influenza virus infectivity by inhibiting hemagglutination (HA) activity. This study demonstrates a novel mechanism by which curcumin inhibits the infectivity of enveloped viruses. In all analyzed enveloped viruses, including the influenza virus, curcumin inhibited plaque formation. In contrast, the nonenveloped enterovirus 71 remained unaffected by curcumin treatment. We evaluated the effects of curcumin on the membrane structure using fluorescent dye (sulforhodamine B; SRB)-containing liposomes that mimic the viral envelope. Curcumin treatment induced the leakage of SRB from these liposomes and the addition of the influenza virus reduced the leakage, indicating that curcumin disrupts the integrity of the membranes of viral envelopes and of liposomes. When testing liposomes of various diameters, we detected higher levels of SRB leakage from the smaller-sized liposomes than from the larger liposomes. Interestingly, the curcumin concentration required to reduce plaque formation was lower for the influenza virus (approximately 100 nm in diameter) than for the pseudorabies virus (approximately 180 nm) and the vaccinia virus (roughly 335 × 200 × 200 nm). These data provide insights on the molecular antiviral mechanisms of curcumin and its potential use as an antiviral agent for enveloped viruses. PMID:23658730

  1. Allosteric Inhibition of Human Immunodeficiency Virus Integrase

    PubMed Central

    Gupta, Kushol; Brady, Troy; Dyer, Benjamin M.; Malani, Nirav; Hwang, Young; Male, Frances; Nolte, Robert T.; Wang, Liping; Velthuisen, Emile; Jeffrey, Jerry; Van Duyne, Gregory D.; Bushman, Frederic D.

    2014-01-01

    HIV-1 replication in the presence of antiviral agents results in evolution of drug-resistant variants, motivating the search for additional drug classes. Here we report studies of GSK1264, which was identified as a compound that disrupts the interaction between HIV-1 integrase (IN) and the cellular factor lens epithelium-derived growth factor (LEDGF)/p75. GSK1264 displayed potent antiviral activity and was found to bind at the site occupied by LEDGF/p75 on IN by x-ray crystallography. Assays of HIV replication in the presence of GSK1264 showed only modest inhibition of the early infection steps and little effect on integration targeting, which is guided by the LEDGF/p75·IN interaction. In contrast, inhibition of late replication steps was more potent. Particle production was normal, but particles showed reduced infectivity. GSK1264 promoted aggregation of IN and preformed LEDGF/p75·IN complexes, suggesting a mechanism of inhibition. LEDGF/p75 was not displaced from IN during aggregation, indicating trapping of LEDGF/p75 in aggregates. Aggregation assays with truncated IN variants revealed that a construct with catalytic and C-terminal domains of IN only formed an open polymer associated with efficient drug-induced aggregation. These data suggest that the allosteric inhibitors of IN are promising antiviral agents and provide new information on their mechanism of action. PMID:24904063

  2. Eye Blink Startle Responses in Behaviorally Inhibited and Uninhibited Children

    ERIC Educational Resources Information Center

    van Brakel, Anna M. L.; Muris, Peter; Derks, Wendy

    2006-01-01

    The present study examined the startle reflex as a physiological marker of behavioral inhibition. Participants were 7 to 12-year-old children who had been previously identified as inhibited or uninhibited as part of an ongoing longitudinal study on the role of behavioral inhibition in the development of anxiety disorders. Analysis of their scores…

  3. Mechanism of zinc-mediated inhibition of caspase-9

    E-print Network

    Hardy, Jeanne

    Mechanism of zinc-mediated inhibition of caspase-9 Kristen L. Huber and Jeanne A. Hardy* Department; Accepted 25 April 2012 DOI: 10.1002/pro.2090 Published online 9 May 2012 proteinscience.org Abstract: Zinc-mediated inhibition is implicated in global caspase regulation, with relief of zinc- mediated inhibition central

  4. differential equations dynamical systems Inhibition of Bacterial Respiration

    E-print Network

    differential equations dynamical systems Inhibition of Bacterial Respiration Suppose we have consequences. To start off, let's consider the dynamics of respiration without inhibition. Suppose we add of x on which the nonlinear inhibition of respiration becomes large? (f) Show that there is a unique

  5. Chemistry and mechanism of urease inhibition.

    PubMed

    Amtul, Z; Rahman, Atta-Ur; Siddiqui, R A; Choudhary, M I

    2002-07-01

    Studies on enzyme inhibition remain an important area of pharmaceutical research since these studies have led to the discoveries of drugs useful in a variety of physiological conditions. The enzyme inhibitors can interact with enzymes and block their activity towards natural substrates. Urease inhibitors have recently attracted much attention as potential new anti-ulcer drugs. Ironically, urease was the first enzyme crystallized but its mechanism of action is still largely misunderstood. This chapter therefore reviews comprehensive developments in the field of urease inhibitors. Inhibitors of urease can be broadly classified into two categories: (1) active site directed (substrate-like), (2) mechanism-based directed. We present here the examples of selected inhibitors along with their mechanisms of action to characterize their mode of urease inhibition. The observations that urease due to its high substrate (urea) specificity can only bind to a few inhibitors with a similar binding mode as urea is also discussed. Several non-covalent interactions including hydrogen bonds and hydrophobic contacts stabilize the enzyme-inhibitor complex. Regardless of the class of compound, it is reported that only a few functional groups with electronegative atoms such as oxygen, nitrogen and sulfur act either as bidentate (mostly), tridentate (rarely), or as ligand-chelator to form octahedral complexes with two slightly distorted octahedral Ni ions of the enzyme. Bulky groups attached to the pharmacophore were found to decrease the activity of inhibitors, since the lack of a bulky attachment makes it easier for urease inhibitors to enter the substrate-binding pocket as well as avoid unfavorable steric interactions with amino acid residues in its vicinity. This review is intended to provide highlights of the inhibition of urease by hydroxamic acids (HXAs), phosphorodiamidates (PPDs), imidazoles, phosphazene and related compounds. These compounds are compared to previously reported urease inhibitors for the catalytic models proposed for urease activity. The differences in inhibition of urease activities from plants and of bacterial origin by various inhibitors and physiological implications of urease inhibition are discussed. PMID:12132990

  6. Inhibition of hepatic uptake transporters by flavonoids.

    PubMed

    Mandery, Kathrin; Balk, Bettina; Bujok, Krystyna; Schmidt, Ingrid; Fromm, Martin F; Glaeser, Hartmut

    2012-05-12

    Members of the human SLC superfamily such as organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, and organic cation transporter 1 (OCT1) are drug uptake transporters that are localised on the basolateral membrane of hepatocytes mediating the uptake of drugs such as atorvastatin and metformin into hepatocytes. Ingredients of food such as flavonoids influence the effects of drugs, e.g. by inhibition of drug transporters. Therefore, we investigated the impact of the Ginkgo biloba flavonoids apigenin, kaempferol, and quercetin, and the grapefruit flavonoids naringenin, naringin, and rutin on the OATP1B1, OATP1B3, and OCT1 transport activity. Transporter expressing HEK293 cell lines were used with [3H]sulfobromophthalein ([3H]BSP) as substrate for OATP1B1 and OATP1B3, [3H]atorvastatin as substrate for OATP1B1, and [3H]1-methyl-4-phenylpyridinium ([3H]MPP(+)) as substrate for OCT1. The G. biloba flavonoids showed a competitive inhibition of the OATP1B1- and OATP1B3-mediated [3H]BSP and the OATP1B1-mediated [3H]atorvastatin uptake. Quercetin was the most potent inhibitor of the OATP1B1- and OATP1B3-mediated [3H]BSP transport with K(i)-values of 8.8±0.8?M and 7.8±1.7?M, respectively. For the inhibition of the OATP1B1-mediated [3H]atorvastatin transport, apigenin was the most potent inhibitor with a K(i) value of 0.6±0.2?M. Among the grapefruit flavonoids, naringenin was the most potent inhibitor of the OATP1B1- and OATP1B3-mediated [3H]BSP transport with IC(50)-values of 81.6±1.1?M and 101.1±1.1?M, respectively. All investigated flavonoids showed no significant inhibition of the OCT1-mediated [3H]MPP(+) uptake. Taken together, these in vitro studies showed that the investigated flavonoids inhibit the OATP1B1- and OATP1B3-mediated drug transport, which could be a mechanism for food-drug interactions in humans. PMID:22394605

  7. Differential effects of cognitive inhibition and intelligence on creativity

    PubMed Central

    Benedek, Mathias; Franz, Fabiola; Heene, Moritz; Neubauer, Aljoscha C.

    2012-01-01

    There are different conceptions about how cognitive inhibition is related to creativity. Creativity has either been associated with effective inhibition, or with disinhibition, or with an adaptive engagement of inhibition. In this study, we examined the relationship of cognitive inhibition, assessed by means of the random motor generation task, with different measures of creativity. We also analyzed whether this relation is mediated by intelligence. We generally found a positive correlation of inhibition and creativity measures. Moreover, latent variable analyses indicate that inhibition may primarily promote the fluency of ideas, whereas intelligence specifically promotes the originality of ideas. These findings support the notion that creative thought involves executive processes and may help to better understand the differential role of inhibition and intelligence in creativity. PMID:22945970

  8. Anthranilic acid release in adenosine-inhibited cultures of Saccharomyces cerevisiae and its inhibition by thiamin.

    PubMed

    Iwashima, A; Kawasaki, Y; Kimura, Y; Hasegawa, T

    1992-10-01

    Adenosine, at 1 mM concentrations or above, was found to have a fungistatic effect on Saccharomyces cerevisiae. A substance with amethyst fluorescence was detected in the medium of adenosine-inhibited cultures of S. cerevisiae. This compound was isolated and physicochemically identified as anthranilic acid. Both the inhibition of growth and release of anthranilic acid induced by adenosine were abrogated by thiamin or by the pyrimidine portion of thiamin, 2-methyl-4-amino-5-hdroxymethyl-pyrimidine (hydroxymethyl-pyrimidine); the latter was found to restore intracellular thiamin content that had been reduced by adenosine. It was demonstrated that effects of thiamin and hydroxymethylpyrimidine on S. cerevisiae cultured with adenosine resulted from their inhibition of adenosine uptake by growing yeast cells. PMID:1426996

  9. INHIBITION IN THE EYE OF LIMULUS

    PubMed Central

    Hartline, H K.; Wagner, Henry G; Ratliff, Floyd

    1956-01-01

    In the compound lateral eye of Limulus each ommatidium functions as a single receptor unit in the discharge of impulses in the optic nerve. Impulses originate in the eccentric cell of each ommatidium and are conducted in its axon, which runs without interruption through an extensive plexus of nerve fibers to become a fiber of the optic nerve. The plexus makes interconnections among the ommatidia, but its exact organization is not understood. The ability of an ommatidium to discharge impulses in the axon of its eccentric cell is reduced by illumination of other ommatidia in its neighborhood: the threshold to light is raised, the number of impulses discharged in response to a suprathreshold flash of light is diminished, and the frequency with which impulses are discharged during steady illumination is decreased. Also, the activity that can be elicited under certain conditions when an ommatidium is in darkness can be inhibited similarly. There is no evidence for the spread of excitatory influences in the eye of Limulus. The inhibitory influence exerted upon an ommatidium that is discharging impulses at a steady rate begins, shortly after the onset of the illumination on neighboring ommatidia, with a sudden deep minimum in the frequency of discharge. After partial recovery, the frequency is maintained at a depressed level until the illumination on the neighboring receptors is turned off, following which there is prompt, though not instantaneous recovery to the original frequency. The inhibition is exerted directly upon the sensitive structure within the ommatidium: it has been observed when the impulses were recorded by a microelectrode thrust into an ommatidium, as well as when they were recorded more proximally in single fibers dissected from the optic nerve. Receptor units of the eye often inhibit one another mutually. This has been observed by recording the activity of two optic nerve fibers simultaneously. The mediation of the inhibitory influence appears to depend upon the integrity of nervous interconnections in the plexus: cutting the lateral connections to an ommatidium abolishes the inhibition exerted upon it. The nature of the influence that is mediated by the plexus and the mechanism whereby it exerts its inhibitory action on the receptor units are not known. The depression of the frequency of the discharge of nerve impulses from an ommatidium increases approximately linearly with the logarithm of the intensity of illumination on receptors in its vicinity. Inhibition of the discharge from an ommatidium is greater the larger the area of the eye illuminated in its vicinity. However, equal increments of area become less effective as the total area is increased. The response of an ommatidium is most effectively inhibited by the illumination of ommatidia that are close to it; the effectiveness diminishes with increasing distance, but may extend for several millimeters. Illumination of a fixed region of the eye at constant intensity produces a depression of the frequency of discharge of impulses from a nearby ommatidium that is approximately constant, irrespective of the level of excitation of the ommatidium. The inhibitory interaction in the eye of Limulus is an integrative process that is important in determining the patterns of nervous activity in the visual system. It is analogous to the inhibitory component of the interaction that takes place in the vertebrate retina. Inhibitory interaction results in the exaggeration of differences in sensory activity from different regions of the eye illuminated at different intensities, thus enhancing visual contrast. PMID:13319654

  10. Inhibition, Executive Function, and Freezing of Gait

    PubMed Central

    Cohen, Rajal G.; Klein, Krystal A.; Nomura, Mariko; Fleming, Michael; Mancini, Martina; Giladi, Nir; Nutt, John G.; Horak, Fay B.

    2014-01-01

    Background Studies suggest that freezing of gait (FoG) in people with Parkinson’s disease (PD) is associated with declines in executive function (EF). However, EF is multi-faceted, including three dissociable components: inhibiting prepotent responses, switching between task sets, and updating working memory. Objective This study investigated which aspect of EF is most strongly associated with FoG in PD. Method Three groups were studied: adults with PD (with and without FoG) and age-matched, healthy adults. All participants completed a battery of cognitive tasks previously shown to discriminate among the three EF components. Participants also completed a turning-in-place task that was scored for FoG by neurologists blind to subjects’ self-reported FoG. Results Compared to both other groups, participants with FoG showed significant performance deficits in tasks associated with inhibitory control, even after accounting for differences in disease severity, but no significant deficits in task-switching or updating working memory. Surprisingly, the strongest effect was an intermittent tendency of participants with FoG to hesitate, and thus miss the response window, on go trials in the Go-Nogo task. The FoG group also made slower responses in the conflict condition of the Stroop task. Physician-rated FoG scores were correlated both with failures to respond on go trials and with failures to inhibit responses on nogo trials in the Go-Nogo task. Conclusion These results suggest that FoG is associated with a specific inability to appropriately engage and release inhibition, rather than with a general executive deficit. PMID:24496099

  11. CCR7 signaling inhibits T cell proliferation.

    PubMed

    Ziegler, Ekkehard; Oberbarnscheidt, Martin; Bulfone-Paus, Silvia; Förster, Reinhold; Kunzendorf, Ulrich; Krautwald, Stefan

    2007-11-15

    CCR7 and its ligands, CCL19 and CCL21, are responsible for directing the migration of T cells and dendritic cells into lymph nodes, where these cells play an important role in the initiation of the immune response. Recently, we have shown that systemic application of CCL19-IgG is able to inhibit the colocalization of T cells and dendritic cells within secondary lymphoid organs, resulting in pronounced immunosuppression with reduced allograft rejection after organ transplantation. In this study, we demonstrate that the application of sustained high concentrations of either soluble or immobilized CCL19 and CCL21 elicits an inhibitory program in T cells. We show that these ligands specifically interfere with cell proliferation and IL-2 secretion of CCR7(+) cells. This could be demonstrated for human and murine T cells and was valid for both CD4(+) and CD8(+) T cells. In contrast, CCL19 had no inhibitory effect on T cells from CCR7 knockout mice, but CCR7(-/-) T cells showed a proliferative response upon TCR-stimulation similar to that of CCL19-treated wild-type cells. Furthermore, the inhibition of proliferation is associated with delayed degradation of the cyclin-dependent kinase (CDK) inhibitor p27(Kip1) and the down-regulation of CDK1. This shows that CCR7 signaling is linked to cell cycle control and that sustained engagement of CCR7, either by high concentrations of soluble ligands or by high density of immobilized ligands, is capable of inducing cell cycle arrest in TCR-stimulated cells. Thus, CCR7, a chemokine receptor that has been demonstrated to play an essential role during activation of the immune response, is also competent to directly inhibit T cell proliferation. PMID:17982037

  12. Inhibition of ?-galactosidases with mono- and disaccharides

    NASA Astrophysics Data System (ADS)

    Pilipenko, O. S.; Atyaksheva, L. F.; Chukhrai, E. S.

    2010-01-01

    It was demonstrated that, in reactions of the hydrolysis of model substrate 2-nitrophenyl-?-D-galactopyranoside (2-NPGP) monosaccharides D-fructose and D-xylose with hydroxyl substituents oppositely directed at the neighboring carbon atoms in the furan ring, as in D-glucose, act as noncompetitive inhibitors of ?-galactosidase from E. coli; for mushroom, ?-galactosidases from P. canescens and A. oryzae D-galactose is a stronger inhibitor. It was also found that the inhibition constant is the highest in the case of the most active enzyme ( E. coli) and is the lowest for the least active one ( P. canescens).

  13. Inhibition of AGEs formation by natural products.

    PubMed

    Nagai, Ryoji; Shirakawa, Jun-Ichi; Ohno, Rei-Ichi; Moroishi, Narumi; Nagai, Mime

    2014-02-01

    Since advanced glycation end-products (AGEs) inhibitors such as benfotiamine, pyridoxamine and aminoguanidine significantly inhibit the development of retinopathy and neuropathy in streptozotocin-induced diabetic rats, treatment with AGEs inhibitors is believed to be a potential strategy for preventing lifestyle-related diseases such as diabetic complications and atherosclerosis. Furthermore, preventive medicine is the most important approach to preventing lifestyle-related diseases, and improving daily nutritional intake is thought to prevent the pathogenesis of such diseases. Therefore, AGEs inhibitors that can be obtained from daily meals are preferred to prescribed drugs. In this article, we describe a strategy for developing new AGEs inhibitors from natural products. PMID:23504149

  14. Inhibition of forearm EMG by palatal myoclonus.

    PubMed

    Elble, R J

    1991-01-01

    The forearm electromyogram (EMG), pharyngeal EMG, and wrist tremor were recorded simultaneously from a 74-year-old woman with the syndrome of palatal myoclonus and progressive ataxia. Her wrist tremor had the characteristics of enhanced physiologic tremor. The enhancement of her tremor was attributable to 50- to 80-ms silent periods in the forearm EMG that followed the 1.9-Hz bursts of palatal myoclonus by 50 to 60 ms. This observation and those of previous authors support the notion that rhythmic olivocerebellar discharges can cause tremorogenic excitation and inhibition of postural EMG activity in the upper extremities. PMID:1758450

  15. IGF-1 receptor antagonism inhibits autophagy

    E-print Network

    Renna, Maurizio; Bento, Carla F.; Fleming, Angeleen; Menzies, Fiona M.; Siddiqi, Farah H.; Ravikumar, Brinda; Puri, Claudia; Garcia-Arencibia, Moises; Sadiq, Oana; Corrochano, Silvia; Carter, Sarah; Brown, Steve D. M.; Acevedo-Arozena, Abraham; Rubinsztein, David C.

    2013-06-25

    -regulation in model organisms increases longevity (7). In mammalian cells, autophagosomes are formed from precursor membrane structures that include a complex of the autophagic proteins Atg5, Atg12 and Atg16L1. †The authors wish it to be known that, in their opinion... –4) and neurode- generative insults (6,7). Since IGF-1 has been reported to block autophagy throughAKT inhibition, which would be expected to occur via AKT activation of the direct autophagy inhibitor rapa- mycin complex 1 (mTORC1) (12,13), we anticipated chronic...

  16. Formation and inhibition of photochemical smog

    SciTech Connect

    Heicklen, J.

    1987-01-01

    Photochemical smog is caused by a free-radical chain mechanism which converts NO to NO/sub 2/. The NO/sub 2/ further reacts to produce ozone, nitric acid, and peracylnitrates. This chain mechanism can be inhibited by suitable free-radical scavengers. The chemistry and toxicology of one such free-radical scavenger, diethylhydroxylamine, has been studied in depth. It has been shown to be effective, safe, and practical for use in urban atmospheres to prevent photochemical smog formation. 42 references.

  17. Expressive Inhibition Following Interpersonal Trauma: An Analysis of Reported Function

    PubMed Central

    Clapp, Joshua D.; Jones, Judiann M.; Jaconis, Maryanne; Olsen, Shira A.; Woodward, Matthew J.; Beck, J. Gayle

    2014-01-01

    Existing research indicates veterans with PTSD may deliberately inhibit the expression of emotion. However, the degree to which inhibition generalizes to other trauma populations and the specific reasons survivors with PTSD inhibit expression remains unclear. The present study looked to evaluate expressive inhibition among survivors of intimate partner violence (N = 74), to determine reasons for inhibition in this population, and to examine whether any justifications for inhibition are unique to individuals with PTSD. The frequency and intensity of inhibition scores were similar to those noted in previous research although no differences were observed across women with and without PTSD. Self-reported justifications for inhibition indicated five general themes: Concern for others, Mistrust/fear of exploitation, Perception of others as indifferent/uncaring, Control/Experiential avoidance, and Situation-specific inhibition. Only mistrust/exploitation motives were uniquely associated with PTSD. Whereas expressive inhibition may be elevated within help-seeking samples, individuals who develop PTSD appear to hold unique reasons for restricting emotional expression. PMID:24507632

  18. Inhibition of pathologic retinal neovascularization by ?-defensins

    PubMed Central

    Economopoulou, Matina; Bdeir, Khalil; Cines, Douglas B.; Fogt, Franz; Bdeir, Yasmina; Lubkowski, Jacek; Lu, Wuyuan; Preissner, Klaus T.; Hammes, Hans-Peter; Chavakis, Triantafyllos

    2005-01-01

    Proliferative retinopathies, such as those complicating prematurity and diabetes, are major causes of blindness. A prominent feature of these retinopathies is excessive neovascularization, which is orchestrated by the hypoxia-induced vascular endothelial growth factor (VEGF) stimulating endothelial cells and the integrin-mediated adhesive interactions of endothelial cells with extracellular matrix components such as fibronectin (FN). Recently, we demonstrated that ?-defensins interfere with ?5?1–FN interactions and dependent endothelial cell functions. Here, ?-defensins were studied in hypoxia-induced proliferative retinopathy. In vitro, ?-defensins specifically inhibited ?5?1-integrin–dependent migration of bovine retinal endothelial cells (BRECs) to FN, attenuated the VEGF-stimulated increase in endothelial permeability, and blocked BREC proliferation and capillary sprout formation in 3-dimensional fibrin-matrices. An up-regulation of ?1-integrin and FN was observed in the retinal vessels in the mouse model of hypoxia-induced retinal angiogenesis. Systemic and local administration of ?-defensins reduced retinal neovascularization by 45% and 60%, respectively, and this effect was comparable to the inhibitory effect of ?5?1-blocking antibody. ?-Defensins were detected in human diabetic retinas associated with normal retinal vessels but were absent from proliferative lesions. Together, these data show that ?-defensins inhibit pathologic retinal neovascularization in vivo and may provide a clinically efficient strategy against proliferative retinopathies. PMID:16123222

  19. Inhibition Of Washed Sludge With Sodium Nitrite

    SciTech Connect

    Congdon, J. W.; Lozier, J. S.

    2012-09-25

    This report describes the results of electrochemical tests used to determine the relationship between the concentration of the aggressive anions in washed sludge and the minimum effective inhibitor concentration. Sodium nitrate was added as the inhibitor because of its compatibility with the DWPF process. A minimum of 0.05M nitrite is required to inhibit the washed sludge simulant solution used in this study. When the worst case compositions and safety margins are considered, it is expected that a minimum operating limit of nearly 0.1M nitrite will be specified. The validity of this limit is dependent on the accuracy of the concentrations and solubility splits previously reported. Sodium nitrite additions to obtain 0.1M nitrite concentrations in washed sludge will necessitate the additional washing of washed precipitate in order to decrease its sodium nitrite inhibitor requirements sufficiently to remain below the sodium limits in the feed to the DWPF. Nitrite will be the controlling anion in "fresh" washed sludge unless the soluble chloride concentration is about ten times higher than predicted by the solubility splits. Inhibition of "aged" washed sludge will not be a problem unless significant chloride dissolution occurs during storage. It will be very important tomonitor the composition of washed sludge during processing and storage.

  20. Tigecycline inhibits proliferation of Acanthamoeba castellanii.

    PubMed

    Jha, Bijay Kumar; Seo, Incheol; Kong, Hyun-Hee; Suh, Seong-Il; Suh, Min-Ho; Baek, Won-Ki

    2015-03-01

    Acanthamoeba is an opportunistic protozoan parasite responsible for different diseases in humans, such as granulomatous amoebic encephalitis and amoebic keratitis. Tigecycline, a third-generation tetracycline antibiotic, has potential activity to treat most of the antibiotic resistant bacterial infections. The effects of tigecycline in eukaryotic cells as well as parasites are less well studied. In the present study, we tested the effects of tigecycline on trophozoites of Acanthamoeba castellanii. The inhibitory effect of tigecycline on Acanthamoeba was determined by resazurin reduction and trypan blue exclusion assays. We found that tigecycline significantly inhibited the growth of Acanthamoeba (46.4 % inhibition at the concentration of 100 ?M) without affecting cell viability and induction of encystation, whereas other tetracycline groups of antibiotics such as tetracycline and doxycycline showed no inhibitory effects. Furthermore, tigecycline decreased cellular adenosine triphosphate (ATP) level by 26 % than the control and increased mitochondrial mass, suggesting mitochondrial dysfunction in tigecycline-treated cells. These findings suggest that mitochondrial dysfunction with decreased ATP production might play an important mechanism of tigecycline in suppression of Acanthamoeba proliferation. PMID:25563616

  1. Inhibition of nickel precipitation by organic ligands

    SciTech Connect

    Hu, H.L.; Nikolaidis, N.P.; Grasso, D.

    1996-11-01

    Wastewaters from electroplating are very complex due to the composition of the plating baths. A nickel plating bath typically consists of a nickel source (nickel chloride or nickel sulfate), complexing agents to solubilize nickel ions controlling their concentration in the solution, buffering agents to maintain pH, brighteners to improve brightness of the plated metal, stabilizers (inhibitors) to prevent undesired reactions, accelerators to enhance speed of reactions, wetting agents to reduce surface tension at the metal surface, and reducing agents (only for electroless nickel plating) to supply electrons for reduction of the nickel. Alkaline precipitation is the most common method of recovering nickel from wastewaters. However, organic constituents found in the wastewaters can mask or completely inhibit the precipitation of nickel. The objective of this study was to conduct an equilibrium study to explore the inhibition behavior of various organic ligands on nickel precipitation. This will lay the groundwork for development of technologies efficacious in the treatment of complexed nickel. The organic ligands used in this study are EDTA, triethanolamine (TEA), gluconate, and tartrate.

  2. Salinomycin, A Polyether Ionophoric Antibiotic, Inhibits Adipogenesis

    PubMed Central

    Szkudlarek-Mikho, Maria; Saunders, Rudel A.; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-01-01

    The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor ?. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy. PMID:23123626

  3. Salinomycin, a polyether ionophoric antibiotic, inhibits adipogenesis.

    PubMed

    Szkudlarek-Mikho, Maria; Saunders, Rudel A; Yap, Sook Fan; Ngeow, Yun Fong; Chin, Khew-Voon

    2012-11-30

    The polyether ionophoric antibiotics including monensin, salinomycin, and narasin, are widely used in veterinary medicine and as food additives and growth promoters in animal husbandry including poultry farming. Their effects on human health, however, are not fully understood. Recent studies showed that salinomycin is a cancer stem cell inhibitor. Since poultry consumption has risen sharply in the last three decades, we asked whether the consumption of meat tainted with growth promoting antibiotics might have effects on adipose cells. We showed in this report that the ionophoric antibiotics inhibit the differentiation of preadipocytes into adipocytes. The block of differentiation is not due to the induction of apoptosis nor the inhibition of cell proliferation. In addition, salinomycin also suppresses the transcriptional activity of the CCAAT/enhancer binding proteins and the peroxisome proliferator-activated receptor ?. These results suggest that the ionophoric antibiotics can be exploited as novel anti-obesity therapeutics and as pharmacological probes for the study of adipose biology. Further, the pharmacological effects of salinomycin could be a harbinger of its toxicity on the adipose tissue and other susceptible target cells in cancer therapy. PMID:23123626

  4. A Wee1 checkpoint inhibits anaphase onset

    PubMed Central

    Lianga, Noel; Williams, Elizabeth C.; Kennedy, Erin K.; Doré, Carole; Pilon, Sophie; Girard, Stéphanie L.; Deneault, Jean-Sebastien

    2013-01-01

    Cdk1 drives both mitotic entry and the metaphase-to-anaphase transition. Past work has shown that Wee1 inhibition of Cdk1 blocks mitotic entry. Here we show that the budding yeast Wee1 kinase, Swe1, also restrains the metaphase-to-anaphase transition by preventing Cdk1 phosphorylation and activation of the mitotic form of the anaphase-promoting complex/cyclosome (APCCdc20). Deletion of SWE1 or its opposing phosphatase MIH1 (the budding yeast cdc25+) altered the timing of anaphase onset, and activation of the Swe1-dependent morphogenesis checkpoint or overexpression of Swe1 blocked cells in metaphase with reduced APC activity in vivo and in vitro. The morphogenesis checkpoint also depended on Cdc55, a regulatory subunit of protein phosphatase 2A (PP2A). cdc55? checkpoint defects were rescued by mutating 12 Cdk1 phosphorylation sites on the APC, demonstrating that the APC is a target of this checkpoint. These data suggest a model in which stepwise activation of Cdk1 and inhibition of PP2ACdc55 triggers anaphase onset. PMID:23751495

  5. Inhibition of dioscin on Saprolegnia in vitro.

    PubMed

    Liu, Lei; Shen, Yu-Feng; Liu, Guang-Lu; Ling, Fei; Liu, Xin-Yang; Hu, Kun; Yang, Xian-Le; Wang, Gao-Xue

    2015-12-01

    As one of the most serious pathogens in the freshwater aquatic environment, Saprolegnia can induce a high mortality rate during the fish egg incubation period. This study investigated the anti-Saprolegnia activity of a total of 108 plants on Saprolegnia parasitica in vitro and Dioscorea collettii was selected for further studies. By loading on an open silica gel column and eluting with petroleum ether-ethyl acetate-methanol, dioscin (C45H72O16) was isolated from D. collettii. Saprolegnia parasitica growth was inhibited significantly when dioscin concentration was more than 2.0 mg L(-1). When compared with formalin and hydrogen peroxide, dioscin showed a higher inhibitory effect. As potential inhibition mechanisms, dioscin could cause the S. parasitica mycelium morphologic damage, dense folds, or disheveled protuberances observed by field emission scanning electron microscopy and the influx of Propidium iodide. The structural changes in the treated mycelium were indicative of an efficient anti-Saprolegnia activity of dioscin. The oxidative stress results showed that dioscin also accumulated reactive oxygen species excessively and increased total antioxidant and superoxide dismutase activity. These situations could render S. parasitica more vulnerable to oxidative damage. Additionally, when dioscin concentration was less than 2.0 mg L(-1), the survival rate of embryos was more than 70%. Therefore, the use of dioscin could be a viable way of preventing and controlling saprolegniasis. PMID:26472687

  6. Bortezomib inhibits cell proliferation in prostate cancer

    PubMed Central

    ZHENG, REN-PING; WANG, WEI; WEI, CHUAN-DONG

    2015-01-01

    Despite the improvement in chemotherapeutic agents, the outcome of patients with prostate cancer remains poor. It is therefore imperative that new anticancer drugs are explored. The aim of the present study was to investigate the inhibitory effect of bortezomib on DU145 prostate cancer cells. The DU145 cell proliferation rate was detected via MTT assay prior to and following exposure to various concentrations of bortezomib, and the level of cell apoptosis and the cell cycle distribution were tested using flow cytometry. In addition, western blotting was used to measure the expression of Bcl-2-interacting killer (Bik) and active-caspase-3. The results showed that bortezomib inhibited the proliferation of DU145 cells in a time- and dose-dependent manner. Following treatment with 1.6 µmol/l bortezomib, the DU145 cells showed marked nuclear condensation, chromatin condensation and fragmentation. Analysis of the cell cycle revealed a significantly increased percentage of cells in the G0/G1 phase and a decreased percentage in the S and G2/M phases. The rate of DU145 cell apoptosis was significantly higher in the bortezomib group than that in the control group, and this was accompanied by an enhanced expression of Bik and active-caspase-3. It can be concluded that bortezomib inhibits the proliferation of DU145 cells by inducing apoptosis. The underlying mechanism may involve the upregulation of Bik and active-caspase-3 expression.

  7. Inhibition of Flavobacterium psychrophilum adhesion in vitro.

    PubMed

    Papadopoulou, Anna; Howell, Amy; Wiklund, Tom

    2015-12-01

    Flavobacterium psychrophilum, a bacterium known for its adhesion ability to surfaces, has recently been shown to express phenotypic variation, as smooth and rough colony types in vitro. The aim of this study was to assess the effect of different compounds on adhesion of both phenotypes of F. psychrophilum to polystyrene surfaces of 96-well microtiter plates. Cells of F. psychrophilum of both phenotypes (10(8) CFU ml(-1)) were treated with different compounds for 1 h at 15°C and were subsequently allowed to adhere to polystyrene surfaces. The adhered cells were stained with crystal violet and optical density measured at 595 nm. The compounds were classified as non, weak, moderate or strong inhibitors of the F. psychrophilum adhesion. The results showed that a combination of selected carbohydrates, D- and L-amino acids, phytochemicals, an ion chelating agent (EDTA) and proteinase K strongly inhibited the adhesion of mainly smooth cells. We suggest that the compounds inhibit the cell adhesion by presumably disrupting the protein-protein interactions that hold smooth cells together and by negatively affecting the surface hydrophobicity of smooth cells. In contrast, rough cells exhibit resistance to most inhibitor compounds. PMID:26500088

  8. Immunoperoxidase inhibition assay for rabies antibody detection.

    PubMed

    Batista, H B C R; Lima, F E S; Maletich, D; Silva, A C R; Vicentini, F K; Roehe, L R; Spilki, F R; Franco, A C; Roehe, P M

    2011-06-01

    An immunoperoxidase inhibition assay (IIA) for detection of rabies antibodies in human sera is described. Diluted test sera are added to microplates with paraformaldehyde-fixed, CER cells infected with rabies virus. Antibodies in test sera compete with a rabies polyclonal rabbit antiserum which was added subsequently. Next, an anti-rabbit IgG-peroxidase conjugate is added and the reaction developed by the addition of the substrate 3-amino-9-ethylcarbazole (AEC). The performance of the assay was compared to that of the "simplified fluorescence inhibition microtest" (SFIMT), an established virus neutralization assay, by testing 422 human sera. The IIA displayed 97.6% sensitivity, 98% specificity and 97.6% accuracy (Kappa correlation coefficient=0.9). The IIA results can be read by standard light microscopy, where the clearly identifiable specific staining is visible in antibody-negative sera, in contrast to the absence of staining in antibody-positive samples. The assay does not require monoclonal antibodies or production of large amounts of virus; furthermore, protein purification steps or specialized equipment are not necessary for its performance. The IIA was shown to be suitable for detection of rabies antibodies in human sera, with sensitivity, specificity and accuracy comparable to that of a neutralization-based assay. This assay may be advantageous over other similar methods designed to detect rabies-specific binding antibodies, in that it can be easily introduced into laboratories, provided basic cell culture facilities are available. PMID:21458492

  9. Bivalency as a principle for proteasome inhibition

    PubMed Central

    Loidl, Günther; Groll, Michael; Musiol, Hans-Jürgen; Huber, Robert; Moroder, Luis

    1999-01-01

    The proteasome, a multicatalytic protease, is known to degrade unfolded polypeptides with low specificity in substrate selection and cleavage pattern. This lack of well-defined substrate specificities makes the design of peptide-based highly selective inhibitors extremely difficult. However, the x-ray structure of the proteasome from Saccharomyces cerevisiae reveals a unique topography of the six active sites in the inner chamber of the protease, which lends itself to strategies of specific multivalent inhibition. Structure-derived active site separation distances were exploited for the design of homo- and heterobivalent inhibitors based on peptide aldehyde head groups and polyoxyethylene as spacer element. Polyoxyethylene was chosen as a flexible, linear, and proteasome-resistant polymer to mimic unfolded polypeptide chains and thus to allow access to the proteolytic chamber. Spacer lengths were selected that satisfy the inter- and intra-ring distances for occupation of the active sites from the S subsites. X-ray analysis of the proteasome/bivalent inhibitor complexes confirmed independent recognition and binding of the inhibitory head groups. Their inhibitory potencies, which are by 2 orders of magnitude enhanced, compared with pegylated monovalent inhibitors, result from the bivalent binding. The principle of multivalency, ubiquitous in nature, has been successfully applied in the past to enhance affinity and avidity of ligands in molecular recognition processes. The present study confirms its utility also for inhibition of multicatalytic protease complexes. PMID:10318898

  10. Calcineurin/NFAT signalling inhibits myeloid haematopoiesis

    PubMed Central

    Fric, Jan; Lim, Clarice X F; Koh, Esther G L; Hofmann, Benjamin; Chen, Jinmiao; Tay, Hock Soon; Isa, Siti Aminah Bte Mohammad; Mortellaro, Alessandra; Ruedl, Christiane; Ricciardi-Castagnoli, Paola

    2012-01-01

    Nuclear factor of activated T cells (NFAT) comprises a family of transcription factors that regulate T cell development, activation and differentiation. NFAT signalling can also mediate granulocyte and dendritic cell (DC) activation, but it is unknown whether NFAT influences their development from progenitors. Here, we report a novel role for calcineurin/NFAT signalling as a negative regulator of myeloid haematopoiesis. Reconstituting lethally irradiated mice with haematopoietic stem cells expressing an NFAT-inhibitory peptide resulted in enhanced development of the myeloid compartment. Culturing bone marrow cells in media supplemented with Flt3-L in the presence of the calcineurin/NFAT inhibitor Cyclosporin A increased numbers of differentiated DC. Global gene expression analysis of untreated DC and NFAT-inhibited DC revealed differential expression of transcripts that regulate cell cycle and apoptosis. In conclusion, these results provide evidence that calcineurin/NFAT signalling negatively regulates myeloid lineage development. The finding that inhibition of NFAT enhances myeloid development provides a novel insight into understanding how the treatment with drugs targeting calcineurin/NFAT signalling influence the homeostasis of the innate immune system. PMID:22311511

  11. A Fusion-Inhibiting Peptide against Rift Valley Fever Virus Inhibits Multiple, Diverse Viruses

    E-print Network

    Bird, Centers for Disease Control and Prevention, United States of America Received April 17, 2013, we show that infectivity can be inhibited for diverse, unrelated RNA viruses that have Class I (Ebola acidification and rearrangement of Gc, the peptide is then able to specifically bind to Gc and prevent fusion

  12. Ketoconazole Inhibits the Cellular Uptake of Anandamide via Inhibition of FAAH at Pharmacologically Relevant Concentrations

    PubMed Central

    Björklund, Emmelie; Larsson, Therése N. L.; Jacobsson, Stig O. P.; Fowler, Christopher J.

    2014-01-01

    Background The antifungal compound ketoconazole has, in addition to its ability to interfere with fungal ergosterol synthesis, effects upon other enzymes including human CYP3A4, CYP17, lipoxygenase and thromboxane synthetase. In the present study, we have investigated whether ketoconazole affects the cellular uptake and hydrolysis of the endogenous cannabinoid receptor ligand anandamide (AEA). Methodology/Principal Findings The effects of ketoconazole upon endocannabinoid uptake were investigated using HepG2, CaCo2, PC-3 and C6 cell lines. Fatty acid amide hydrolase (FAAH) activity was measured in HepG2 cell lysates and in intact C6 cells. Ketoconazole inhibited the uptake of AEA by HepG2 cells and CaCo2 cells with IC50 values of 17 and 18 µM, respectively. In contrast, it had modest effects upon AEA uptake in PC-3 cells, which have a low expression of FAAH. In cell-free HepG2 lysates, ketoconazole inhibited FAAH activity with an IC50 value (for the inhibitable component) of 34 µM. Conclusions/Significance The present study indicates that ketoconazole can inhibit the cellular uptake of AEA at pharmacologically relevant concentrations, primarily due to its effects upon FAAH. Ketoconazole may be useful as a template for the design of dual-action FAAH/CYP17 inhibitors as a novel strategy for the treatment of prostate cancer. PMID:24466356

  13. Distinct Neural Correlates for Two Types of Inhibition in Bilinguals: Response Inhibition versus Interference Suppression

    ERIC Educational Resources Information Center

    Luk, Gigi; Anderson, John A. E.; Craik, Fergus I. M.; Grady, Cheryl; Bialystok, Ellen

    2010-01-01

    To examine the effects of bilingualism on cognitive control, we studied monolingual and bilingual young adults performing a flanker task with functional MRI. The trial types of primary interest for this report were incongruent and no-go trials, representing interference suppression and response inhibition, respectively. Response times were similar…

  14. Rethinking Inhibition Theory: On the Problematic Status of the Inhibition Theory for Forgetting

    ERIC Educational Resources Information Center

    Raaijmakers, Jeroen G. W.; Jakab, Emoke

    2013-01-01

    The standard textbook account of interference and forgetting is based on the assumption that retrieval of a memory trace is affected by competition by other memory traces. In recent years, a number of researchers have questioned this view and have proposed an alternative account of forgetting based on a mechanism of suppression. In this inhibition

  15. Thymol inhibits Staphylococcus aureus internalization into bovine mammary epithelial cells by inhibiting NF-?B 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 ?-defensin (BNBD5), and the inhibition of NF-?B activation in bMEC infected with S. aureus. Our results showed that thymol (16-64 ?g/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-?B activation in a dose-dependent manner. In conclusion, these results indicated that thymol inhibits S. aureus internalization into bMEC by inhibiting NF-?B activation. PMID:24583152

  16. Doxycycline inhibits leukemic cell migration via inhibition of matrix metalloproteinases and phosphorylation of focal adhesion kinase

    PubMed Central

    WANG, CHUNHUAI; XIANG, RU; ZHANG, XIANGZHONG; CHEN, YUNXIAN

    2015-01-01

    Doxycycline, a tetracycline-based antibiotic, has been reported to attenuate melanoma cell migration through inhibiting the focal adhesion kinase (FAK) signaling pathway. However, it remains to be elucidated whether doxycycline exerts this effect on leukemia cell migration. The present study aimed to examine the role of doxycycline in leukemia cell migration. The invasion capacities of the human leukemia cell lines KG1a (acute myelogenous leukemia) and K562 (chronic myelogenous leukemia) were evaluated using Matrigel® matrix-coated Transwell® chamber assays; leukemic cell lines treated with doxycycline (1 µg/ml) or anti-?1-integrin antibodies were added to the upper chamber, while untreated cells were included as controls. Reverse transcription quantitative polymerase chain reaction was performed in order to further understand the influence of doxycycline treatment on the expression of FAK and gelatinases in the KG1a and K562 leukemic cell lines. In addition, FAK protein expression and phosphorylation were determined using western blot analysis in order to investigate the mechanism by which doxycycline inhibited leukemic cell migration. The results revealed that doxycycline treatment significantly attenuated the migration of KG1a and K562 cells, which was demonstrated to be associated with inhibition of the expression and phosphorylation of FAK. In addition, doxycycline treatment inhibited matrix metalloproteinase (MMP)-2 and MMP-9 expression. Furthermore, incubation with blocking anti-?1-integrin antibodies had an analogous inhibitory effect on leukemic cell migration to that of doxycycline. In conclusion, the results of the present study suggested that doxycycline attenuated leukemic cell migration through inhibiting the FAK signaling pathway. Therefore, doxycycline may have potential for use as a novel strategy for the treatment of leukemia. PMID:26004127

  17. Molecular mechanisms of DNA repair inhibition by caffeine

    SciTech Connect

    Selby, C.P.; Sancar, A. )

    1990-05-01

    Caffeine potentiates the mutagenic and lethal effects of genotoxic agents. It is thought that this is due, at least in some organisms, to inhibition of DNA repair. However, direct evidence for inhibition of repair enzymes has been lacking. Using purified Escherichia coli DNA photolyase and (A)BC excinuclease, we show that the drug inhibits photoreactivation and nucleotide excision repair by two different mechanisms. Caffeine inhibits photoreactivation by interfering with the specific binding of photolyase to damaged DNA, and it inhibits nucleotide excision repair by promoting nonspecific binding of the damage-recognition subunit, UvrA, of (A)BC excinuclease. A number of other intercalators, including acriflavin and ethidium bromide, appear to inhibit the excinuclease by a similar mechanism--that is, by trapping the UvrA subunit in nonproductive complexes on undamaged DNA.

  18. Principles governing the operation of synaptic inhibition in dendrites.

    PubMed

    Gidon, Albert; Segev, Idan

    2012-07-26

    Synaptic inhibition plays a key role in shaping the dynamics of neuronal networks and selecting cell assemblies. Typically, an inhibitory axon contacts a particular dendritic subdomain of its target neuron, where it often makes 10-20 synapses, sometimes on very distal branches. The functional implications of such a connectivity pattern are not well understood. Our experimentally based theoretical study highlights several new and counterintuitive principles for dendritic inhibition. We show that distal "off-path" rather than proximal "on-path" inhibition effectively dampens proximal excitable dendritic "hotspots," thus powerfully controlling the neuron's output. Additionally, with multiple synaptic contacts, inhibition operates globally, spreading centripetally hundreds of micrometers from the inhibitory synapses. Consequently, inhibition in regions lacking inhibitory synapses may exceed that at the synaptic sites themselves. These results offer new insights into the synergetic effect of dendritic inhibition in controlling dendritic excitability and plasticity and in dynamically molding functional dendritic subdomains and their output. PMID:22841317

  19. Tangeretin inhibits extracellular-signal-regulated kinase (ERK) phosphorylation.

    PubMed

    Van Slambrouck, Séverine; Parmar, Virinder S; Sharma, Sunil K; De Bondt, Bart; Foré, Fleur; Coopman, Peter; Vanhoecke, Barbara W; Boterberg, Tom; Depypere, Herman T; Leclercq, Guy; Bracke, Marc E

    2005-03-14

    Tangeretin is a methoxyflavone from citrus fruits, which inhibits growth of human mammary cancer cells and cytolysis by natural killer cells. Attempting to unravel the flavonoid's action mechanism, we found that it inhibited extracellular-signal-regulated kinases 1/2 (ERK1/2) phosphorylation in a dose- and time-dependent way. In human T47D mammary cancer cells this inhibition was optimally observed after priming with estradiol. The spectrum of the intracellular signalling kinase inhibition was narrow and comparison of structural congeners showed that inhibition of ERK phosphorylation was not unique for tangeretin. Our data add tangeretin to the list of small kinase inhibitors with a restricted intracellular inhibition profile. PMID:15757658

  20. Inhibition of Macrophage Migration by Nucleotide-Containing Streptococcal Preparations

    PubMed Central

    Bültmann, B.; Heymer, B.; Schachenmayr, W.; Haferkamp, O.; Schmidt, W. C.

    1973-01-01

    Certain extracts of streptococcal cell walls are known to inhibit macrophage migration in vitro. In this study, we attempted to identify the streptococcal components responsible for this phenomenon. Trypsinized cell walls and cytoplasm from groups A and B streptococci were extracted with hot formamide followed by acetone precipitation. Subsequent gel filtration in aqueous solutions yielded a fraction devoid of C-carbohydrate and containing mostly oligonucleotides, apparently derived from streptococcal cytoplasm. This fraction significantly inhibited the migration of peritoneal exudate cells from rats sensitized to groups A and B streptococci. It was noteworthy that no inhibition of migration was observed with cells from nonsensitized animals or control rats injected with BCG or complete Freund adjuvant. Similarly, no inhibition was obtained with formamide extracts of calf thymus RNA. Although the inhibition does not show specificity for streptococcal groups, it seems to have immunological specificity since prior sensitization with streptococci is required for migration inhibition. PMID:4542963

  1. Inhibition of granulocyte migration by tiotropium bromide

    PubMed Central

    2011-01-01

    Study objectives Neutrophil influx into the airways is an important mechanism in the pathophysiology of the inflammatory process in the airways of patients with chronic obstructive pulmonary disease (COPD). Previously it was shown that anticholinergic drugs reduce the release of non-neuronal paracrine mediators, which modulate inflammation in the airways. On this basis, we investigated the ability of the long-acting anticholinergic tiotropium bromide to inhibit a) alveolar macrophage (AM)-mediated chemotaxis of neutrophils, and b) cellular release of reactive oxygen species (ROS). Method AM and neutrophils were collected from 71 COPD patients. Nanomolar concentrations of tiotropium bromide were tested in AM cultured up to 20 h with LPS (1 ?g/ml). AM supernatant was tested for TNF?, IL8, IL6, LTB4, GM-CSF, MIP?/? and ROS. It was further used in a 96-well chemotaxis chamber to stimulate the migration of fluorescence labelled neutrophils. Control stimulants consisted of acetylcholine (ACh), carbachol, muscarine or oxotremorine and in part PMA (phorbol myristate acetate, 0.1 ?g/ml). Potential contribution of M1-3-receptors was ascertained by a) analysis of mRNA transcription by RT-PCR, and b) co-incubation with selective M-receptor inhibitors. Results Supernatant from AM stimulated with LPS induced neutrophilic migration which could be reduced by tiotropium in a dose dependent manner: 22.1 ± 10.2 (3 nM), 26.5 ± 18,4 (30 nM), and 37.8 ± 24.0 (300 nM, p < 0.001 compared to non-LPS activated AM). Concomitantly TNF? release of stimulated AM dropped by 19.2 ± 7.2% of control (p = 0.001). Tiotropium bromide did not affect cellular IL8, IL6, LTB4, GM-CSF and MIP?/? release in this setting. Tiotropium (30 nM) reduced ROS release of LPS stimulated AM by 36.1 ± 15.2% (p = 0.002) and in carbachol stimulated AM by 46.2 ± 30.2 (p < 0.001). M3R gene expression dominated over M2R and M1R. Chemotaxis inhibitory effect of tiotropium bromide was mainly driven by M3R inhibition. Conclusion Our data confirm that inhibiting muscarinic cholinergic receptors with tiotropium bromide reduces TNF? mediated chemotactic properties and ROS release of human AM, and thus may contribute to lessen cellular inflammation. PMID:21352583

  2. High molecular weight polysaccharide that binds and inhibits virus

    DOEpatents

    Konowalchuk, Thomas W

    2014-01-14

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods on inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  3. Inhibition of the ablation rate of graphite by gaseous chlorine.

    NASA Technical Reports Server (NTRS)

    Maahs, H. G.

    1972-01-01

    Investigation of the inhibiting effect of gaseous chlorine on the ablation rate of graphite. It is shown that small amounts of chlorine gas, when present in a supersonic high-temperature air environment, can inhibit the ablation rate of graphite and depress its surface temperature below that measured in pure air. The ablation inhibition performance of chlorine is presented in graphs in terms of mass loss rate and surface temperature depression as a function of chlorine concentration.

  4. Method for inhibiting oxidation of metal sulfide-containing material

    DOEpatents

    Elsetinow, Alicia; Borda, Michael J.; Schoonen, Martin A.; Strongin, Daniel R.

    2006-12-26

    The present invention provides means for inhibiting the oxidation of a metal sulfide-containing material, such as ore mine waste rock or metal sulfide taiulings, by coating the metal sulfide-containing material with an oxidation-inhibiting two-tail lipid coating (12) thereon, thereby inhibiting oxidation of the metal sulfide-containing material in acid mine drainage conditions. The lipids may be selected from phospholipids, sphingolipids, glycolipids and combinations thereof.

  5. Competition, inhibition, and critical periods of cortical plasticity.

    PubMed

    Trachtenberg, Joshua T

    2015-12-01

    Maturation of cortical inhibition just after eye opening is a necessary precedent for the emergence of competitive, experience-dependent ocular dominance plasticity in the visual cortex. What inhibition is doing in this context, though, is not clear. Here I outline new hypotheses on the roles of somatic and dendritic inhibition in the opening and closure of critical periods, and their roles in the competitive processes therein. PMID:26126153

  6. Inhibition of Mild Steel Corrosion under Hydrodynamic Conditions

    SciTech Connect

    Musa, Ahmed Y.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Takriff, Mohd Sobri; Kamarudin, Siti Kartom; Daud, Abdul Razak

    2010-07-07

    The inhibition of mild steel corrosion by 4-amino-5-phenyl-4H-1, 2, 4-trizole-3-thiol (APTT) in 2.5 M H{sub 2}SO{sub 4} solution and the effect of hydrodynamic condition on inhibition process were studied. The hydrodynamic condition experiments are simulated by rotating cylinder electrode (RCE). Change of open circuit potential (OCP) with immersion time and potentiodynamic polarization were used to study the effect of hydrodynamic conditions on the inhibition process. Results obtained from changes of open circuit potential (OCP) with immersion time, and potentiodynamic polarization are in good agreement and indicated that the inhibition process was flow velocity dependence.

  7. Erasing Sensorimotor Memories via PKM? Inhibition

    PubMed Central

    von Kraus, Lee Michael; Sacktor, Todd Charlton; Francis, Joseph Thachil

    2010-01-01

    Sensorimotor cortex has a role in procedural learning. Previous studies suggested that this learning is subserved by long-term potentiation (LTP), which is in turn maintained by the persistently active kinase, protein kinase Mzeta (PKM?). Whereas the role of PKM? in animal models of declarative knowledge is established, its effect on procedural knowledge is not well understood. Here we show that PKM? inhibition, via injection of zeta inhibitory peptide (ZIP) into the rat sensorimotor cortex, disrupts sensorimotor memories for a skilled reaching task even after several weeks of training. The rate of relearning the task after the memory disruption by ZIP was indistinguishable from the rate of initial learning, suggesting no significant savings after the memory loss. These results indicate a shared molecular mechanism of storage for declarative and procedural forms of memory. PMID:20559553

  8. [Inhibition of neutrophil adhesion by pectic galacturonans].

    PubMed

    Popov, S V; Ovodova, R G; Popova, G Iu; Nikitina, I R; Ovodov, Iu S

    2007-01-01

    The inhibition of the adhesion of neutrophils to fibronectin by the fragments of the main galacturonan chain of the following pectins was demonstrated: comaruman from the marsh cinquefoil Comarum polustre, bergenan from the Siberian tea Bergenia crassifolia, lemnan from the duckweed Lemna minor, zosteran from the seagrass Zostera marina, and citrus pectin. The parent pectins, except for comaruman, did not affect the cell adhesion. Galacturonans prepared from the starting pectins by acidic hydrolysis were shown to reduce the neutrophil adhesion stimulated by phorbol 12-myristate 13-acetate (1.625 microM) and dithiothreitol (0.5 mM) at a concentration of 50-200 microg/ml. The presence of carbohydrate chains with molecular masses higher than 300, from 100 to 300, and from 50 to 100 kDa in the galacturonan fractions was proved by membrane ultrafiltration. PMID:17375675

  9. Pericellular Hydrogel/Nanonets Inhibit Cancer Cells

    PubMed Central

    Kuang, Yi; Shi, Junfeng; Li, Jie; Yuan, Dan; Alberti, Kyle A.; Xu, Qiaobing

    2014-01-01

    Fibrils formed by proteins are vital components for cells. However, selective formation of xenogenous nanofibrils of small molecules on mammalian cells has yet to be observed. Here we report an unexpected observation of hydrogel/nanonets of a small D-peptide derivative in pericellular space. Surface and secretory phosphatases dephosphorylate a precursor of a hydrogelator to trigger the self-assembly of the hydrogelator and to result in pericellular hydrogel/nanonets selectively around the cancer cells that overexpress phosphatases. Cell based assays confirm that the pericellular hydrogel/nanonets block cellular mass exchange to induce apoptosis of cancer cells, including multidrug-resistance (MDR) cancer cells, MES-SA/Dx5. Pericellular hydrogel/nanonets of small molecules to exhibit distinct functions illustrates a fundamentally new way to engineer molecular assemblies spatiotemporally in cellular microenvironment for inhibiting cancer cell growth and even metastasis. PMID:24820524

  10. Paliperidon mediated modification of cortical inhibition.

    PubMed

    Prikryl, Radovan; Ustohal, Libor; Kucerova, Hana Prikrylova; Ceskova, Eva

    2009-01-01

    Transcranial magnetic stimulation is a neurophysiological method which enables direct quantitative in vivo assessment of cortical excitability and inhibition. The aim of the study was to assess the impact of paliperidone on the motor threshold and cortical silent period, in a drug-naive patient, with first episode schizophrenia using this technique. Paliperidone monotherapy caused a significant reduction of severity of schizophrenic symptomatology in the patient. At the same time, a significant prolongation of the cortical silent period, from 118.68 ms before to 185.13 ms after therapy, occurred. Because the cortical silent period is a function of GABA(B) receptors, we can assume that paliperidone may have the ability to enhance GABA(B) receptor-mediated neurotransmission. PMID:19855366

  11. PI3K? Inhibitors That Inhibit Metastasis

    PubMed Central

    Schmidt-Kittler, Oleg; Zhu, Jiuxiang; Yang, Jian; Liu, Guosheng; Hendricks, William; Lengauer, Christoph; Gabelli, Sandra B.; Kinzler, Kenneth W.; Vogelstein, Bert; Huso, David L.; Zhou, Shibin

    2010-01-01

    Previous genetic analyses have suggested that mutations of the genes encoding PI3K? facilitate invasion and metastasis but have less effect on primary tumor growth. These findings have major implications for therapeutics but have not been factored into pre-clinical drug development designs. Here we show that the inhibition of PI3K? by newly designed small molecule inhibitors prevented metastasis formation in mice but had much less effect on the growth of subcutaneous xenografts or primary intra-abdominal tumors. These data support the idea that PI3K? plays an important role in the metastatic process and suggest a more informed strategy for selecting drugs worthy of further development for clinical application. PMID:21179398

  12. Multi-kinase inhibition in ovarian cancer

    PubMed Central

    Dent, Paul

    2014-01-01

    Sorafenib (Nexavar) is a multi-kinase inhibitor that was developed as an inhibitor of RAF-1, in the ERK1/2 pathway, but which was subsequently shown to inhibit class III tyrosine kinase receptors.1 More recently regorafenib (Stivarga) has been developed, which is a further fluorinated version of sorafenib with greater bioavailability and similar inhibitory properties against RAF-1/class III RTKs.2 Some of the anti-tumor effects of sorafenib have been ascribed to anti-angiogenic actions of this agent on endothelial associated kinases such as VEGFR2. Other effects of sorafenib clearly have to be due to its effects on the inherent biology of the tumor cells themselves. For example, through various mechanisms sorafenib has been shown in the laboratory and the clinic to suppress expression of the protective protein MCL-1.3 Sorafenib has also been linked to inhibition of STAT3, NF?B, and activation of the death receptor CD95.4 Sorafenib is routinely dosed daily (400 mg BID) and 7 d after the start of dosing has a Cmax of ~21 ?M with a nadir at 12 h of ~10 ?M, and is a highly protein bound based on in vitro assays.5 Despite this in vitro binding data sorafenib has profound in vivo effects on tumor cells in renal carcinoma and hepatocellular carcinoma patients; cells which are not per se addicted to high activity oncogene signals that are targets of sorafenib/regorafenib. Thus the precise stable bioavailable level of sorafenib/regorafenib in patient plasma is not known. PMID:24309512

  13. 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

  14. Pharmacologic inhibition of lactate production prevents myofibroblast differentiation.

    PubMed

    Kottmann, Robert Matthew; Trawick, Emma; Judge, Jennifer L; Wahl, Lindsay A; Epa, Amali P; Owens, Kristina M; Thatcher, Thomas H; Phipps, Richard P; Sime, Patricia J

    2015-12-01

    Myofibroblasts are one of the primary cell types responsible for the accumulation of extracellular matrix in fibrosing diseases, and targeting myofibroblast differentiation is an important therapeutic strategy for the treatment of pulmonary fibrosis. Transforming growth factor-? (TGF-?) has been shown to be an important inducer of myofibroblast differentiation. We previously demonstrated that lactate dehydrogenase and its metabolic product lactic acid are important mediators of myofibroblast differentiation, via acid-induced activation of latent TGF-?. Here we explore whether pharmacologic inhibition of LDH activity can prevent TGF-?-induced myofibroblast differentiation. Primary human lung fibroblasts from healthy patients and those with pulmonary fibrosis were treated with TGF-? and or gossypol, an LDH inhibitor. Protein and RNA were analyzed for markers of myofibroblast differentiation and extracellular matrix generation. Gossypol inhibited TGF-?-induced expression of the myofibroblast marker ?-smooth muscle actin (?-SMA) in a dose-dependent manner in both healthy and fibrotic human lung fibroblasts. Gossypol also inhibited expression of collagen 1, collagen 3, and fibronectin. Gossypol inhibited LDH activity, the generation of extracellular lactic acid, and the rate of extracellular acidification in a dose-dependent manner. Furthermore, gossypol inhibited TGF-? bioactivity in a dose-dependent manner. Concurrent treatment with an LDH siRNA increased the ability of gossypol to inhibit TGF-?-induced myofibroblast differentiation. Gossypol inhibits TGF-?-induced myofibroblast differentiation through inhibition of LDH, inhibition of extracellular accumulation of lactic acid, and inhibition of TGF-? bioactivity. These data support the hypothesis that pharmacologic inhibition of LDH may play an important role in the treatment of pulmonary fibrosis. PMID:26408551

  15. Liposomal curcumin inhibits Lewis lung cancer growth primarily through inhibition of angiogenesis

    PubMed Central

    WANG, LIQIANG; ZHANG, JING; CAI, LULU; WEN, JING; SHI, HUASHAN; LI, DAN; GUO, FUCHUN; WANG, YONGSHENG

    2012-01-01

    Curcumin has been proven to effectively inhibit tumor growth by both targeting tumor cells and angiogenesis; however, poor water solubility limits further clinical application. In the present study, we prepared water-soluble liposomal curcumin to investigate its anti-tumor effects and the underlying mechanism. The MTT assay was used to test the anti-proliferative activities for the MS1 murine endothelial and LL/2 Lewis lung cancer cell lines. Apoptosis and cell cycle arrest induced by liposomal curcumin were analysed by flow cytometry. Anti-angiogenic agents and the resulting anti-tumor effects were investigated in a murine lung cancer model. Zebrafish were used to investigate the anti-angiogenic effect of liposomal curcumin in the development of embryos. In vitro, liposomal curcumin inhibited the proliferation of MS1 cells and induced cell cycle arrest and apoptosis. Notably, LL/2 cells showed less sensitivity to the liposomal curcumin in vitro. In vivo, the systemic administration of liposomal curcumin resulted in significant inhibition of tumor growth. CD31 immunohistochemical analysis and alginate encapsulation assay revealed that angiogenesis was decreased by liposomal curcumin treatment. Angiogenesis was also suppressed in the development of zebrafish. Liposomal curcumin showed potent inhibitory activity against murine endothelial cells but not lung cancer cells. Liposomal curcumin treatment is capable of significantly inhibiting tumor growth in vivo, a process that may depend primarily on its anti-angiogenic effects. Our study also indicates that liposomal curcumin may be developed not only for cancer therapy, but also for the treatment of other angiogenesis-related diseases.

  16. Metformin inhibits gastric cancer via the inhibition of HIF1?/PKM2 signaling

    PubMed Central

    Chen, Guangxia; Feng, Wan; Zhang, Shu; Bian, Kangqi; Yang, Yan; Fang, Cheng; Chen, Min; Yang, Jun; Zou, Xiaoping

    2015-01-01

    Recent evidence suggests that anti-diabetic drug metformin prevents cancer progression, but the mechanism by which metformin inhibits tumor growth remains elusive. In this study, we investigated the anticancer role of metformin in gastric cancer and explored the underlying mechanism. The expression of hypoxia inducible factor 1? (HIF1?) and pyruvate kinase M2 (PKM2) in different stages of gastric cancer tissues was detected by immunohistochemistry. Gastric cancer cell viability was evaluated by CCK-8 assay; apoptosis and cell cycle were analyzed by flow cytometry. The expression of PI3K, Akt, HIF1?, PARP, PKM2 and COX in gastric cancer cells was detected by immunofluorescence and Western blot analysis. We found that HIF1? and PKM2 protein expression levels were higher in advanced gastric cancer tissues than in gastritis tissues. Metformin reduced gastric cancer cell viability, invasion and migration. Metformin induced apoptosis and cell cycle arrest in part through inhibiting PARP expression. Metformin downregulated PI3K, Akt, HIF1?, PARP, PKM2 and COX expression. Moreover, overexpression of HIF1? increased gastric cancer cell viability, invasion and migration. In summary, metformin has profound antitumor effect for gastric cancer by inducing intrinsic apoptosis via the inhibition of HIF1?/PKM2 signaling pathway. PMID:26101707

  17. Tumor suppressor XAF1 induces apoptosis, inhibits angiogenesis and inhibits tumor growth in hepatocellular carcinoma

    PubMed Central

    Zhu, Li Ming; Shi, Dong Mei; Dai, Qiang; Cheng, Xiao Jiao; Yao, Wei Yan; Sun, Ping Hu; Ding, Yan Fei; Qiao, Min Min; Wu, Yun Lin; Jiang, Shi Hu; Tu, Shui Ping

    2014-01-01

    X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1), a XIAP-binding protein, is a tumor suppressor gene. XAF1 was silent or expressed lowly in most human malignant tumors. However, the role of XAF1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we investigated the effect of XAF1 on tumor growth and angiogenesis in hepatocellular cancer cells. Our results showed that XAF1 expression was lower in HCC cell lines SMMC-7721, Hep G2 and BEL-7404 and liver cancer tissues than that in paired non-cancer liver tissues. Adenovirus-mediated XAF1 expression (Ad5/F35-XAF1) significantly inhibited cell proliferation and induced apoptosis in HCC cells in dose- and time- dependent manners. Infection of Ad5/F35-XAF1 induced cleavage of caspase -3, -8, -9 and PARP in HCC cells. Furthermore, Ad5/F35-XAF1 treatment significantly suppressed tumor growth in a xenograft model of liver cancer cells. Western Blot and immunohistochemistry staining showed that Ad5/F35-XAF1 treatment suppressed expression of vascular endothelial growth factor (VEGF), which is associated with tumor angiogenesis, in cancer cells and xenograft tumor tissues. Moreover, Ad5/F35-XAF1 treatment prolonged the survival of tumor-bearing mice. Our results demonstrate that XAF1 inhibits tumor growth by inducing apoptosis and inhibiting tumor angiogenesis. XAF1 may be a promising target for liver cancer treatment. PMID:24980821

  18. Tumor suppressor XAF1 induces apoptosis, inhibits angiogenesis and inhibits tumor growth in hepatocellular carcinoma.

    PubMed

    Zhu, Li Ming; Shi, Dong Mei; Dai, Qiang; Cheng, Xiao Jiao; Yao, Wei Yan; Sun, Ping Hu; Ding, Yanfei; Qiao, Min Min; Wu, Yun Lin; Jiang, Shi Hu; Tu, Shui Ping

    2014-07-30

    X-linked inhibitor of apoptosis (XIAP)-associated factor 1 (XAF1), a XIAP-binding protein, is a tumor suppressor gene. XAF1 was silent or expressed lowly in most human malignant tumors. However, the role of XAF1 in hepatocellular carcinoma (HCC) remains unknown. In this study, we investigated the effect of XAF1 on tumor growth and angiogenesis in hepatocellular cancer cells. Our results showed that XAF1 expression was lower in HCC cell lines SMMC-7721, Hep G2 and BEL-7404 and liver cancer tissues than that in paired non-cancer liver tissues. Adenovirus-mediated XAF1 expression (Ad5/F35-XAF1) significantly inhibited cell proliferation and induced apoptosis in HCC cells in dose- and time- dependent manners. Infection of Ad5/F35-XAF1 induced cleavage of caspase -3, -8, -9 and PARP in HCC cells. Furthermore, Ad5/F35-XAF1 treatment significantly suppressed tumor growth in a xenograft model of liver cancer cells. Western Blot and immunohistochemistry staining showed that Ad5/F35-XAF1 treatment suppressed expression of vascular endothelial growth factor (VEGF), which is associated with tumor angiogenesis, in cancer cells and xenograft tumor tissues. Moreover, Ad5/F35-XAF1 treatment prolonged the survival of tumor-bearing mice. Our results demonstrate that XAF1 inhibits tumor growth by inducing apoptosis and inhibiting tumor angiogenesis. XAF1 may be a promising target for liver cancer treatment. PMID:24980821

  19. Linalool inhibits cigarette smoke-induced lung inflammation by inhibiting NF-?B activation.

    PubMed

    Ma, Jianqun; Xu, Hai; Wu, Jun; Qu, Changfa; Sun, Fenglin; Xu, Shidong

    2015-12-01

    Linalool, a natural compound that exists in the essential oils of several aromatic plants species, has been reported to have anti-inflammatory effects. However, the effects of linalool on cigarette smoke (CS)-induced acute lung inflammation have not been reported. In the present study, we investigated the protective effects of linalool on CS-induced acute lung inflammation in mice. Linalool was given i.p. to mice 2h before CS exposure daily for five consecutive days. The numbers of macrophages and neutrophils in bronchoalveolar lavage fluid (BALF) were measured. The production of TNF-?, IL-6, IL-1?, IL-8 and MCP-1 were detected by ELISA. The expression of NF-?B was detected by Western blotting. Our results showed that treatment of linalool significantly attenuated CS-induced lung inflammation, coupled with inhibited the infiltration of inflammatory cells and TNF-?, IL-6, IL-1?, IL-8 and MCP-1 production. Meanwhile, treatment of linalool inhibited CS-induced lung MPO activity and pathological changes. Furthermore, linalool suppressed CS-induced NF-?B activation in a dose-dependent manner. In conclusion, our results demonstrated that linalool protected against CS-induced lung inflammation through inhibiting CS-induced NF-?B activation. PMID:26432179

  20. Mullerian inhibiting substance inhibits growth of a human ovarian cancer in nude mice.

    PubMed Central

    Donahoe, P K; Fuller, A F; Scully, R E; Guy, S R; Budzik, G P

    1981-01-01

    Mullerian inhibiting substance (MIS) was investigated for its ability to inhibit growth of a human ovarian cancer in nude mice. Biologically active preparations from newborn calf testes, obtained after sequential ion exchange chromatography, delayed or prevented growth of a human ovarian cancer (HOC-21) when 2 X 10(6) cells were preincubated with them prior to subcutaneous injection of the tumor cells into Balb/C homozygous nude mice. Preincubation of a human colon carcinoma cells (SW-48) with similar preparations of MIS failed to inhibit growth of the tumor cells in nude mice. Human serous carcinomas are thought to arise from the ovarian surface epithelium, a derivative of the coelomic epithelium of the urogenital ridge, which invaginates to form the mullerian duct early in embryonic life. The neoplastic cells of serous tumors simulate morphologically the lining cells of the fallopian tube, which are derivatives of mullerian duct epithelium. This study provides physiologic confirmation of the mullerian nature of this type of tumor and suggests that MIS may ultimately prove to be effective in its therapy. Images Fig. 1. Fig. 2. PMID:6895157

  1. Direct Inhibition of the Longevity-Promoting Factor SKN-1

    E-print Network

    Blackwell, Keith

    Direct Inhibition of the Longevity-Promoting Factor SKN-1 by Insulin-like Signaling in C. elegans, reductions in IIS increase stress resis- tance and longevity, effects that require the IIS- inhibited FOXO activation. SKN-1 contributes to the increased stress tolerance and longevity resulting from reduced IIS

  2. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  3. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  4. Inhibition of dynamin completely blocks compensatory synaptic vesicle endocytosis

    E-print Network

    Kirchhausen, Tomas

    Inhibition of dynamin completely blocks compensatory synaptic vesicle endocytosis A. Jamila Newton vesicle endocytosis remains unclear. Here, we have tested the role of dynamin in synaptic vesicle endocytosis by using a small molecule called dynasore, which rapidly inhibits the GTPase activity of dynamin

  5. The Influence of Cue Type on Backward Inhibition

    ERIC Educational Resources Information Center

    Arbuthnott, Katherine D.

    2005-01-01

    Backward inhibition is proposed as a process of lateral inhibition that operates during response selection in task switching, reducing interference caused by the most recently abandoned task set. The effect has been observed across a wide range of contexts but is eliminated by using spatial location to cue tasks (K. D. Arbuthnott & T. S. Woodward,…

  6. Physiological Evidence for Response Inhibition in Choice Reaction Time Tasks

    ERIC Educational Resources Information Center

    Burle, Boris; Vidal, Frank; Tandonnet, Christophe; Hasbroucq, Thierry

    2004-01-01

    Inhibition is a widely used notion proposed to account for data obtained in choice reaction time (RT) tasks. However, this concept is weakly supported by empirical facts. In this paper, we review a series of experiments using Hoffman reflex, transcranial magnetic stimulation and electroencephalography to study inhibition in choice RT tasks. We…

  7. Multiple mechanisms allow Mycobacterium tuberculosis to continuously inhibit MHC class

    E-print Network

    Kirschner, Denise

    Multiple mechanisms allow Mycobacterium tuberculosis to continuously inhibit MHC class II as the preferred host for Mycobacterium tuberculosis (Mtb), the intracellular pathogen that causes TB. On the other that Mycobacterium tubercu- losis inhibits a number of macrophage intracellular processes associ- ated with antigen

  8. REGULAR ARTICLE Why calcium inhibits magnesium-dependent enzyme

    E-print Network

    Liao, Rongzhen

    REGULAR ARTICLE Why calcium inhibits magnesium-dependent enzyme phosphoserine phosphatase. Keywords Phosphoserine phosphatase Á Magnesium Á Calcium Á Density functional calculations Á Inhibition mechanism 1 Introduction Phosphoserine phosphatase (PSP, EC 3.1.3.3) is a mono- nuclear magnesium

  9. Dihydropyridines Inhibit Translation and Early Replication of Hepatitis C Virus 

    E-print Network

    Klemashevich, Cory

    2013-05-09

    additional DHP compounds. We also show that DHP compounds inhibit IRES dependent translation in full-length HCV. This inhibition of two separate steps of the viral life cycle may be a unique feature of DHPs making them superior DAAs. Among these DHPs...

  10. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  11. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  12. 46 CFR 154.1740 - Vinyl chloride: Inhibiting and inerting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Vinyl chloride: Inhibiting and inerting. 154.1740... Operating Requirements § 154.1740 Vinyl chloride: Inhibiting and inerting. When a vessel is carrying vinyl chloride, the master shall ensure that: (a) Section 154.1818 is met; or (b) Section 154.1710 is met,...

  13. COMMUNICATION TO THE EDITOR The Inhibition of Escherichia coli lac

    E-print Network

    Relue, Patricia

    COMMUNICATION TO THE EDITOR The Inhibition of Escherichia coli lac Operon Gene Expression to quantitatively describe the inhibition of the Escherichia coli lac operon gene expression by triplex 70: 467­472, 2000 Keywords: genetically structured model; Escherichia coli lac operon; gene

  14. The Affective Consequences of Cognitive Inhibition: Devaluation or Neutralization?

    ERIC Educational Resources Information Center

    Frischen, Alexandra; Ferrey, Anne E.; Burt, Dustin H. R.; Pistchik, Meghan; Fenske, Mark J.

    2012-01-01

    Affective evaluations of previously ignored visual stimuli are more negative than those of novel items or prior targets of attention or response. This has been taken as evidence that inhibition has negative affective consequences. But inhibition could act instead to attenuate or "neutralize" preexisting affective salience, predicting opposite…

  15. Belief Inhibition in Children's Reasoning: Memory-Based Evidence

    ERIC Educational Resources Information Center

    Steegen, Sara; Neys, Wim De

    2012-01-01

    Adult reasoning has been shown as mediated by the inhibition of intuitive beliefs that are in conflict with logic. The current study introduces a classic procedure from the memory field to investigate belief inhibition in 12- to 17-year-old reasoners. A lexical decision task was used to probe the memory accessibility of beliefs that were cued…

  16. Men in the Triangle: Grief, Inhibition, and Defense

    ERIC Educational Resources Information Center

    Clayton, Robert E.

    2015-01-01

    Inhibition of emotional experience is a widely acknowledged characteristic of many Western-raised men. While this affective inhibition may impact men chronically in many ways, it becomes particularly salient when men are bereaved or otherwise grieving and are unable fully to experience normative emotional responses to loss. This article briefly…

  17. Metformin inhibits the inflammatory response associated with cellular transformation and

    E-print Network

    , inhibits cel- lular transformation and selectively kills cancer stem cells in breast cancer cell lines cells compared with non-stem cancer cells in the same population. The ability of metformin to block system (5, 9), and selec- tively inhibits the growth of cancer stem cells (CSCs) in geneti- cally

  18. Simulating cholinesterase inhibition in birds caused by dietary insecticide exposure

    USGS Publications Warehouse

    Corson, M.S.; Mora, M.A.; Grant, W.E.

    1998-01-01

    We describe a stochastic simulation model that simulates avian foraging in an agricultural landscape to evaluate factors affecting dietary insecticide exposure and to predict post-exposure cholinesterase (ChE) inhibition. To evaluate the model, we simulated published field studies and found that model predictions of insecticide decay and ChE inhibition reasonably approximated most observed results. Sensitivity analysis suggested that foraging location usually influenced ChE inhibition more than diet preferences or daily intake rate. Although organophosphorus insecticides usually caused greater inhibition than carbamate insecticides, insecticide toxicity appeared only moderately important. When we simulated impact of heavy insecticide applications during breeding seasons of 15 wild bird species, mean maximum ChE inhibition in most species exceeded 20% at some point. At this level of inhibition, birds may experience nausea and/or may exhibit minor behavioral changes. Simulated risk peaked in April-May and August-September and was lowest in July. ChE inhibition increased with proportion of vegetation in the diet. This model, and ones like it, may help predict insecticide exposure of and sublethal ChE inhibition in grassland animals, thereby reducing dependence of ecological risk assessments on field studies alone.

  19. Cholesterol Depletion Delocalizes Phosphatidylinositol Bisphosphate and Inhibits Hormone-stimulated

    E-print Network

    Pike, Linda J.

    Cholesterol Depletion Delocalizes Phosphatidylinositol Bisphosphate and Inhibits Hormone- enriched domains (DIGs) are cholesterol-enriched mem- brane domains that have been implicated in signal) are compartmentalized in these domains. We report here that depletion of cellular cholesterol leads to the inhibition

  20. Inhibition of fatty acid-supported mitochondrial respiration by cyclosporine.

    PubMed

    Lemmi, C A; Miller, R L; Rajfer, J

    1990-12-01

    We have shown that, in addition to inhibition of the succinate-supported energy pathway (5), CS inhibition of mitochondrial Complex II activity also limits fatty acid oxidation. These results are consistent with the participation of altered lipid metabolism in CS nephrotoxicity. PMID:2288768

  1. Kinetic and Inhibition Studies for the Aerobic Cometabolism of

    E-print Network

    Semprini, Lewis

    Kinetic and Inhibition Studies for the Aerobic Cometabolism of 1,1,1-Trichloroethane, 1 performed for the aerobic cometabolism of 1,1,1- trichloroethane (1,1,1-TCA), 1,1-dichloroethylene (1,1- DCE­508, 2002. Keywords: aerobic cometabolism of CAH mixtures; com- petitive and mixed inhibition; direct linear

  2. Temperature profiles of inhibited flames using Raman spectroscopy

    NASA Technical Reports Server (NTRS)

    Drake, M. C.; Hastie, J. W.

    1981-01-01

    Laser Raman scattering from vibrational and rotational states of N2 and H2 has been used to determine temperature profiles for several H2/O2/N2 flames with and without HBr present. The inhibiting effect of HBr is clearly demonstrated and the derived properties of burning velocity and inhibition index are in good agreement with previous experimental measurements and theoretical calculations.

  3. ORIGINAL ARTICLE Inhibition of Maternal Behaviour by Central Infusion of

    E-print Network

    Saltzman, Wendy

    , the incidence of child abuse rises in families affected by natural disasters (9), whereas infant abuse may@ucr.edu). Stress can inhibit maternal behaviour and increase rates of child abuse in humans and other animals, Madison, WI, USA. Stress can inhibit maternal behaviour and increase the risk of off- spring abuse

  4. Stuttering Inhibition via Altered Auditory Feedback during Scripted Telephone Conversations

    ERIC Educational Resources Information Center

    Hudock, Daniel; Kalinowski, Joseph

    2014-01-01

    Background: Overt stuttering is inhibited by approximately 80% when people who stutter read aloud as they hear an altered form of their speech feedback to them. However, levels of stuttering inhibition vary from 60% to 100% depending on speaking situation and signal presentation. For example, binaural presentations of delayed auditory feedback…

  5. Selective serotonin reuptake inhibition modulates response inhibition in Parkinson’s disease

    PubMed Central

    Ye, Zheng; Altena, Ellemarije; Nombela, Cristina; Housden, Charlotte R.; Maxwell, Helen; Rittman, Timothy; Huddleston, Chelan; Rae, Charlotte L.; Regenthal, Ralf; Sahakian, Barbara J.; Barker, Roger A.; Robbins, Trevor W.

    2014-01-01

    Impulsivity is common in Parkinson’s disease even in the absence of impulse control disorders. It is likely to be multifactorial, including a dopaminergic ‘overdose’ and structural changes in the frontostriatal circuits for motor control. In addition, we proposed that changes in serotonergic projections to the forebrain also contribute to response inhibition in Parkinson’s disease, based on preclinical animal and human studies. We therefore examined whether the selective serotonin reuptake inhibitor citalopram improves response inhibition, in terms of both behaviour and the efficiency of underlying neural mechanisms. This multimodal magnetic resonance imaging study used a double-blind randomized placebo-controlled crossover design with an integrated Stop-Signal and NoGo paradigm. Twenty-one patients with idiopathic Parkinson’s disease (46–76 years old, 11 male, Hoehn and Yahr stage 1.5–3) received 30 mg citalopram or placebo in addition to their usual dopaminergic medication in two separate sessions. Twenty matched healthy control subjects (54–74 years old, 12 male) were tested without medication. The effects of disease and drug on behavioural performance and regional brain activity were analysed using general linear models. In addition, anatomical connectivity was examined using diffusion tensor imaging and tract-based spatial statistics. We confirmed that Parkinson’s disease caused impairment in response inhibition, with longer Stop-Signal Reaction Time and more NoGo errors under placebo compared with controls, without affecting Go reaction times. This was associated with less stop-specific activation in the right inferior frontal cortex, but no significant difference in NoGo-related activation. Although there was no beneficial main effect of citalopram, it reduced Stop-Signal Reaction Time and NoGo errors, and enhanced inferior frontal activation, in patients with relatively more severe disease (higher Unified Parkinson’s Disease Rating Scale motor score). The behavioural effect correlated with the citalopram-induced enhancement of prefrontal activation and the strength of preserved structural connectivity between the frontal and striatal regions. In conclusion, the behavioural effect of citalopram on response inhibition depends on individual differences in prefrontal cortical activation and frontostriatal connectivity. The correlation between disease severity and the effect of citalopram on response inhibition may be due to the progressive loss of forebrain serotonergic projections. These results contribute to a broader understanding of the critical roles of serotonin in regulating cognitive and behavioural control, as well as new strategies for patient stratification in clinical trials of serotonergic treatments in Parkinson’s disease. PMID:24578545

  6. Cyclooxygenase inhibition and baroreflex sensitivity in humans.

    PubMed

    Monahan, Kevin D; Ray, Chester A

    2005-02-01

    Animal studies suggest that prostanoids (i.e., such as prostacyclin) may sensitize or impair baroreceptor and/or baroreflex responsiveness depending on the site of administration and/or inhibition. We tested the hypothesis that acute inhibition of cyclooxygenase (COX), the rate-limiting enzyme in prostanoid synthesis, impairs baroreflex regulation of cardiac period (R-R interval) and muscle sympathetic nerve activity (MSNA) in humans and augments pressor reactivity. Baroreflex sensitivity (BRS) was determined at baseline (preinfusion) and 60 min after (postinfusion) intravenous infusion of a COX antagonist (ketorolac; 45 mg) (24 +/- 1 yr; n = 12) or saline (25 +/- 1 yr; n = 12). BRS was assessed by using the modified Oxford technique (bolus intravenous infusion of nitroprusside followed by phenylephrine). BRS was quantified as the slope of the linear portion of the 1) R-R interval-systolic blood pressure relation (cardiovagal BRS) and 2) MSNA-diastolic blood pressure relation (sympathetic BRS) during pharmacological changes in arterial blood pressure. Ketorolac did not alter cardiovagal (19.4 +/- 2.1 vs. 18.4 +/- 2.4 ms/mmHg preinfusion and postinfusion, respectively) or sympathetic BRS (-2.9 +/- 0.7 vs. -2.6 +/- 0.4 arbitrary units.beat(-1).mmHg(-1)) but significantly decreased a plasma biomarker of prostanoid generation (plasma thromboxane B2) by 53 +/- 11%. Cardiovagal BRS (21.3 +/- 3.8 vs. 21.2 +/- 3.0 ms/mmHg), sympathetic BRS (-3.4 +/- 0.3 vs. -3.2 +/- 0.2 arbitrary units.beat(-1).mmHg(-1)), and thromboxane B2 (change in -1 +/- 12%) were unchanged in the control (saline infusion) group. Pressor responses to steady-state incremental (0.5, 1.0, and 1.5 microg.kg(-1).min(-1)) infusion (5 min/dose) of phenylephrine were not altered by ketorolac (n = 8). Collectively, these data indicate that acute pharmacological antagonism of the COX enzyme does not impair BRS (cardiovagal or sympathetic) or augment pressor reactivity in healthy young adults. PMID:15486039

  7. Basal forebrain neuronal inhibition enables rapid behavioral stopping.

    PubMed

    Mayse, Jeffrey D; Nelson, Geoffrey M; Avila, Irene; Gallagher, Michela; Lin, Shih-Chieh

    2015-10-01

    Cognitive inhibitory control, the ability to rapidly suppress responses inappropriate for the context, is essential for flexible and adaptive behavior. Although most studies on inhibitory control have focused on the fronto-basal-ganglia circuit, we found that rapid behavioral stopping is enabled by neuronal inhibition in the basal forebrain (BF). In rats performing the stop signal task, putative noncholinergic BF neurons with phasic bursting responses to the go signal were nearly completely inhibited by the stop signal. The onset of BF neuronal inhibition was tightly coupled with and temporally preceded the latency to stop, the stop signal reaction time. Artificial inhibition of BF activity in the absence of the stop signal was sufficient to reproduce rapid behavioral stopping. These results reveal a previously unknown subcortical mechanism of rapid inhibitory control by the BF, which provides bidirectional control over the speed of response generation and inhibition. PMID:26368943

  8. Gemcitabine Functions Epigenetically by Inhibiting Repair Mediated DNA Demethylation

    PubMed Central

    Schäfer, Andrea; Schomacher, Lars; Barreto, Guillermo; Döderlein, Gabi; Niehrs, Christof

    2010-01-01

    Gemcitabine is a cytotoxic cytidine analog, which is widely used in anti-cancer therapy. One mechanism by which gemcitabine acts is by inhibiting nucleotide excision repair (NER). Recently NER was implicated in Gadd45 mediated DNA demethylation and epigenetic gene activation. Here we analyzed the effect of gemcitabine on DNA demethylation. We find that gemcitabine inhibits specifically Gadd45a mediated reporter gene activation and DNA demethylation, similar to the topoisomerase I inhibitor camptothecin, which also inhibits NER. In contrast, base excision repair inhibitors had no effect on DNA demethylation. In Xenopus oocytes, gemcitabine inhibits DNA repair synthesis accompanying demethylation of oct4. In mammalian cells, gemcitabine induces DNA hypermethylation and silencing of MLH1. The results indicate that gemcitabine induces epigenetic gene silencing by inhibiting repair mediated DNA demethylation. Thus, gemcitabine can function epigenetically and provides a tool to manipulate DNA methylation. PMID:21124914

  9. Pancreatic polypepetide inhibits pancreatic enzyme secretion via a cholinergic pathway

    SciTech Connect

    Jung, G.; Louie, D.S.; Owyang, C. )

    1987-11-01

    In rat pancreatic slices, rat pancreatic polypeptide (PP) or C-terminal hexapeptide of PP (PP-(31-36)) inhibited potassium-stimulated amylase release in a dose-dependent manner. The inhibition was unaffected by addition of hexamethonium but blocked by atropine. In contrast, PP-(31-36) did not have any effect on acetylcholine- or cholecystokinin octapeptide-stimulated amylase release. In addition, when pancreatic slices were incubated with ({sup 3}H)choline, PP-(31-36) inhibited the potassium-evoked release of synthesized ({sup 3}H)acetylcholine in a dose-dependent manner. The inhibitory action of PP was unaffected by adrenergic, dopaminergic, or opioid receptor antagonists. Thus PP inhibits pancreatic enzyme secretion via presynaptic modulation of acetylcholine release. This newly identified pathway provides a novel mechanism for hormonal inhibition of pancreatic enzyme secretion via modulation of the classic neurotransmitter function.

  10. Dual mechanism of neuronal ensemble inhibition in primary auditory cortex

    PubMed Central

    O’Connell, M.N; Falchier, A; McGinnis, T; Schroeder, C.E; Lakatos, P

    2011-01-01

    SUMMARY Inhibition plays an essential role in shaping and refining the brain s representation of sensory stimulus attributes. In primary auditory cortex (A1), so-called “sideband” inhibition helps to sharpen the tuning of local neuronal responses. Several distinct types of anatomical circuitry could underlie sideband inhibition, including direct thalamocortical (TC) afferents, as well as indirect intracortical mechanisms. The goal of the present study was to characterize sideband inhibition in A1 and to determine its mechanism by analyzing laminar profiles of neuronal ensemble activity. Our results indicate that both lemniscal and non-lemniscal TC afferents play a role in inhibitory responses via feed-forward inhibition and oscillatory phase reset respectively. We propose that the dynamic modulation of excitability in A1 due to the phase reset of ongoing oscillations may alter the tuning of local neuronal ensembles and can be regarded as a flexible overlay upon the more obligatory system of lemniscal feed-forward type responses. PMID:21338888

  11. Thymoquinone Inhibits Escherichia coli ATP Synthase and Cell Growth

    PubMed Central

    Ahmad, Zulfiqar; Laughlin, Thomas F.; Kady, Ismail O.

    2015-01-01

    We examined the thymoquinone induced inhibition of purified F1 or membrane bound F1FO E. coli ATP synthase. Both purified F1 and membrane bound F1FO were completely inhibited by thymoquinone with no residual ATPase activity. The process of inhibition was fully reversible and identical in both membrane bound F1Fo and purified F1 preparations. Moreover, thymoquinone induced inhibition of ATP synthase expressing wild-type E. coli cell growth and non-inhibition of ATPase gene deleted null control cells demonstrates that ATP synthase is a molecular target for thymoquinone. This also links the beneficial dietary based antimicrobial and anticancer effects of thymoquinone to its inhibitory action on ATP synthase. PMID:25996607

  12. STUDIES ON THE CORRELATION BETWEEN BLOOD CHOLINESTERASE INHIBITION AND "TARGET TISSUE" INHIBITION IN PESTICIDE-TREATED RATS

    EPA Science Inventory

    Inhibition of cholinesterase activity in the blood has been proposed as an index of ChE activity in tissues targeted by ChE-inhibiting pesticides, including the muscle end-plate region and the central nervous system(CNS). hile opinions vary regarding the utility of blood ChE acti...

  13. Cyclooxygenase inhibition in ischemic brain injury

    E-print Network

    Eduardo Candelario-Jalil; Bernd L. Fiebich

    2008-07-09

    Neuroinflammation is one of the key pathological events involved in the progression of brain damage caused by cerebral ischemia. Metabolism of arachidonic acid through cyclooxygenase (COX) enzymes is known to be actively involved in the neuroinflammatory events leading to neuronal death after ischemia. Two isoforms of COX, termed COX-1 and COX-2, have been identified. Unlike COX-1, COX-2 expression is dramatically induced by ischemia and appears to be an effector of tissue damage. This review article will focus specifically on the involvement of COX isozymes in brain ischemia. We will discuss issues related to the biochemistry and selective pharmacological inhibition of COX enzymes, and further refer to their expression in the brain under normal conditions and following excitotoxicity and ischemic cerebral injury. We will review present knowledge of the relative contribution of each COX isoform to the brain ischemic pathology, based on data from investigations utilizing selective COX-1/COX-2 inhibitors and genetic knockout mouse models. The mechanisms of neurotoxicity associated with increased COX activity after ischemia will also be examined. Finally, we will provide a critical evaluation of the therapeutic potential of COX inhibitors in cerebral ischemia and discuss new targets downstream of COX with potential neuroprotective ability.

  14. Advances in Bacterial Methionine Aminopeptidase Inhibition.

    PubMed

    Helgren, Travis R; Wangtrakuldee, Phumvadee; Staker, Bart L; Hagen, Timothy J

    2016-01-01

    Methionine aminopeptidases (MetAPs) are metalloenzymes that cleave the N-terminal methionine from newly synthesized peptides and proteins. These MetAP enzymes are present in bacteria, and knockout experiments have shown that MetAP activity is essential for cell life, suggesting that MetAPs are good antibacterial drug targets. MetAP enzymes are also present in the human host and selectivity is essential. There have been significant structural biology efforts and over 65 protein crystal structures of bacterial MetAPs are deposited into the PDB. This review highlights the available crystallographic data for bacterial MetAPs. Structural comparison of bacterial MetAPs with human MetAPs highlights differences that can lead to selectivity. In addition, this review includes the chemical diversity of molecules that bind and inhibit the bacterial MetAP enzymes. Analysis of the structural biology and chemical space of known bacterial MetAP inhibitors leads to a greater understanding of this antibacterial target and the likely development of potential antibacterial agents. PMID:26268344

  15. Inhibition of Oxidation in Nuclear Graphite

    SciTech Connect

    Phil Winston; James W. Sterbentz; William E. Windes

    2013-10-01

    Graphite is a fundamental material of high temperature gas cooled nuclear reactors, providing both structure and neutron moderation. Its high thermal conductivity, chemical inertness, thermal heat capacity, and high thermal structural stability under normal and off normal conditions contribute to the inherent safety of these reactor designs. One of the primary safety issues for a high temperature graphite reactor core is the possibility of rapid oxidation of the carbon structure during an off normal design basis event where an oxidizing atmosphere (air ingress) can be introduced to the hot core. Although the current Generation IV high temperature reactor designs attempt to mitigate any damage caused by a postualed air ingress event, the use of graphite components that inhibit oxidation is a logical step to increase the safety of these reactors. Recent experimental studies of graphite containing between 5.5 and 7 wt% boron carbide (B4C) indicate that oxidation is dramatically reduced even at prolonged exposures at temperatures up to 900°C. The proposed addition of B4C to graphite components in the nuclear core would necessarily be enriched in B-11 isotope in order to minimize B-10 neutron absorption and graphite swelling. The enriched boron can be added to the graphite during billet fabrication. Experimental oxidation rate results and potential applications for borated graphite in nuclear reactor components will be discussed.

  16. Inhibition of glioblastoma malignancy by Lgl1.

    PubMed

    Gont, Alexander; Hanson, Jennifer E L; Lavictoire, Sylvie J; Daneshmand, Manijeh; Nicholas, Garth; Woulfe, John; Kassam, Amin; Da Silva, Vasco F; Lorimer, Ian A J

    2014-11-30

    lethal giant larvae (lgl) was first identified as a tumor suppressor in Drosophila, where its loss repressed the differentiation and promoted the invasion of neuroblasts, the Drosophila equivalent of the neural stem cell. Recently we have shown that a human homolog of Lgl, Lgl1 (LLGL1), is constitutively phosphorylated and inactivated in glioblastoma cells; this occurs as a downstream consequence of PTEN loss, one of the most frequent genetic events in glioblastoma. Here we have investigated the consequences of this loss of functional Lgl1 in glioblastoma in vivo. We used a doxycycline-inducible system to express a non-phosphorylatable, constitutively active version of Lgl1 (Lgl3SA) in either a glioblastoma cell line or primary glioblastoma cells isolated under neural stem cell culture conditions from patients. In both types of cells, expression of Lgl3SA, but not wild type Lgl1, inhibited cell motility in vitro. Induction of Lgl3SA in intracerebral xenografts markedly reduced the in vivo invasion of primary glioblastoma cells. Lgl3SA expression also induced the differentiation of glioblastoma cells in vitro and in vivo along the neuronal lineage. Thus the central features of Lgl function as a tumor suppressor in Drosophila are conserved in human glioblastoma. PMID:25426552

  17. Stathmin Potentiates Vinflunine and Inhibits Paclitaxel Activity

    PubMed Central

    Malesinski, Soazig; Tsvetkov, Philipp O.; Kruczynski, Anna; Peyrot, Vincent; Devred, François

    2015-01-01

    Cell biology and crystallographic studies have suggested a functional link between stathmin and microtubule targeting agents (MTAs). In a previous study we showed that stathmin increases vinblastine (VLB) binding to tubulin, and that conversely VLB increases stathmin binding to tubulin. This constituted the first biochemical evidence of the direct relationship between stathmin and an antimitotic drug, and revealed a new mechanism of action for VLB. The question remained if the observed interaction was specific for this drug or represented a general phenomenon for all MTAs. In the present study we investigated the binding of recombinant stathmin to purified tubulin in the presence of paclitaxel or another Vinca alkaloid, vinflunine, using Isothermal Titration Calorimetry (ITC). These experiments revealed that stathmin binding to tubulin is increased in the presence of vinflunine, whereas no signal is observed in the presence of paclitaxel. Further investigation using turbidity and co-sedimentation showed that stathmin inhibited paclitaxel microtubule-stabilizing activity. Taken together with the previous study using vinblastine, our results suggest that stathmin can be seen as a modulator of MTA activity and binding to tubulin, providing molecular explanation for multiple previous cellular and in vivo studies showing that stathmin expression level affects MTAs efficiency. PMID:26030092

  18. Inhibition of glioblastoma malignancy by Lgl1

    PubMed Central

    Gont, Alexander; Hanson, Jennifer E.L.; Lavictoire, Sylvie J.; Daneshmand, Manijeh; Nicholas, Garth; Woulfe, John; Kassam, Amin; Da Silva, Vasco F.; Lorimer, Ian A.J.

    2014-01-01

    lethal giant larvae (lgl) was first identified as a tumor suppressor in Drosophila, where its loss repressed the differentiation and promoted the invasion of neuroblasts, the Drosophila equivalent of the neural stem cell. Recently we have shown that a human homolog of Lgl, Lgl1 (LLGL1), is constitutively phosphorylated and inactivated in glioblastoma cells; this occurs as a downstream consequence of PTEN loss, one of the most frequent genetic events in glioblastoma. Here we have investigated the consequences of this loss of functional Lgl1 in glioblastoma in vivo. We used a doxycycline-inducible system to express a non-phosphorylatable, constitutively active version of Lgl1 (Lgl3SA) in either a glioblastoma cell line or primary glioblastoma cells isolated under neural stem cell culture conditions from patients. In both types of cells, expression of Lgl3SA, but not wild type Lgl1, inhibited cell motility in vitro. Induction of Lgl3SA in intracerebral xenografts markedly reduced the in vivo invasion of primary glioblastoma cells. Lgl3SA expression also induced the differentiation of glioblastoma cells in vitro and in vivo along the neuronal lineage. Thus the central features of Lgl function as a tumor suppressor in Drosophila are conserved in human glioblastoma. PMID:25426552

  19. Inhibition of dextromethorphan metabolism by moclobemide.

    PubMed

    Härtter, S; Dingemanse, J; Baier, D; Ziegler, G; Hiemke, C

    1998-01-01

    This pilot study was conducted to evaluate the potential of the new antidepressant moclobemide to inhibit the cytochrome enzyme P4502D6 (CYP2D6) using the cough suppressant dextromethorphan as a substrate in four extensive metabolizers (EM) of debrisoquine. The subjects received seven oral doses of 20 mg dextromethorphan at 4-h intervals over 2 days (1 and 2) and subsequently moclobemide (300 mg b.i.d.) for 9 days. On days 10 and 11, they received seven doses of 20 mg dextromethorphan in addition to moclobemide. During monotreatment and combined treatment, blood was collected on days 2 and 11, respectively, for determination of dextromethorphan and its demethylated metabolites using automated high-performance liquid chromatography with column switching. Concurrent administration of moclobemide markedly reduced the O-demethylation of dextromethorphan, whereas the N-demethylation of dextrorphan to hydroxymorphinan was not affected. The findings indicate that moclobemide can affect the pharmacokinetics of drugs that are mainly metabolized by CYP2D6. PMID:9489930

  20. Hsp90 Inhibition Decreases Mitochondrial Protein Turnover

    PubMed Central

    Margineantu, Daciana H.; Emerson, Christine B.; Diaz, Dolores; Hockenbery, David M.

    2007-01-01

    Background Cells treated with hsp90 inhibitors exhibit pleiotropic changes, including an expansion of the mitochondrial compartment, accompanied by mitochondrial fragmentation and condensed mitochondrial morphology, with ultimate compromise of mitochondrial integrity and apoptosis. Findings We identified several mitochondrial oxidative phosphorylation complex subunits, including several encoded by mtDNA, that are upregulated by hsp90 inhibitors, without corresponding changes in mRNA abundance. Post-transcriptional accumulation of mitochondrial proteins observed with hsp90 inhibitors is also seen in cells treated with proteasome inhibitors. Detailed studies of the OSCP subunit of mitochondrial F1F0-ATPase revealed the presence of mono- and polyubiquitinated OSCP in mitochondrial fractions. We demonstrate that processed OSCP undergoes retrotranslocation to a trypsin-sensitive form associated with the outer mitochondrial membrane. Inhibition of proteasome or hsp90 function results in accumulation of both correctly targeted and retrotranslocated mitochondrial OSCP. Conclusions Cytosolic turnover of mitochondrial proteins demonstrates a novel connection between mitochondrial and cytosolic compartments through the ubiquitin-proteasome system. Analogous to defective protein folding in the endoplasmic reticulum, a mitochondrial unfolded protein response may play a role in the apoptotic effects of hsp90 and proteasome inhibitors. PMID:17957250

  1. Method for inhibiting corrosion in aqueous systems

    DOEpatents

    DeMonbrun, James R. (Knoxville, TN); Schmitt, Charles R. (Oak Ridge, TN); Schreyer, James M. (Oak Ridge, TN)

    1980-01-01

    This invention is a method for inhibiting corrosion in aqueous systems containing components composed of aluminum, copper, iron, or alloys thereof. The method comprises (a) incorporating in the aqueous medium 2-10 ppm by weight of tolyltriazole; an effective amount of a biodegradable organic biocide; 500-1000 ppm by weight of sodium metasilicate; 500-2000 ppm by weight of sodium nitrite; and 500-2000 ppm by weight of sodium tetraborate, all of these concentrations being based on the weight of water in the system; and (b) maintaining the pH of the resulting system in the range of 7.5 to 8.0. The method permits longterm operation with very low corrosion rates and bacteria counts. All of the additives to the system are biodegradable, permitting the treated aqueous medium to be discharged to the environment without violating current regulations. The method has special application to solar systems in which an aqueous medium is circulated through aluminum-alloy heat exchangers.

  2. Chemical interaction: enhancement and inhibition of clastogenicity.

    PubMed

    Anwar, W A

    1993-10-01

    Most environmental exposures involve concurrent or sequential exposure to multiple chemicals in air, water, and food. Interactive effects in carcinogenesis have been described for certain combinations of agents. They are described in terms of enhancement or inhibition of carcinogenesis. Enhancement effects have been documented for cigarette smoking in combination with exposure to asbestos, radon, alcohol, or other exposures. A variety of inhibitors of carcinogenesis have also been described. They are classified into agents preventing formation of carcinogens; blocking agents; and suppressing agents. Assessment of risk from exposure to multiple agents can be derived either from epidemiological studies in relation to actual exposure or from laboratory studies after controlled exposure to different agents. Prediction of how toxic components of mixtures will interact should be based on an understanding of the mechanisms of such interactions. Compounds may interact chemically, yielding new toxic components or causing a change in the biological availability of the existing components or metabolites. In humans, great individual variability in response is to be expected because of genetic heterogeneity or acquired host susceptibility factors. Interaction is thus a key component in the risk assessment process. In this paper, the definition of interaction and the theoretical basis for different types of interaction in cancer causation are reviewed. Epidemiological and experimental studies showing interactive effects of two chemical carcinogens are also presented. PMID:8143617

  3. Inhibiting protein arginine deiminases has antioxidant consequences.

    PubMed

    Witalison, Erin E; Cui, Xiangli; Hofseth, Anne B; Subramanian, Venkataraman; Causey, Corey P; Thompson, Paul R; Hofseth, Lorne J

    2015-04-01

    Ulcerative colitis is a dynamic, idiopathic, chronic inflammatory condition that carries a high colon cancer risk. We previously showed that Cl-amidine, a small-molecule inhibitor of the protein arginine deiminases, suppresses colitis in mice. Because colitis is defined as inflammation of the colon associated with infiltration of white blood cells that release free radicals and citrullination is an inflammation-dependent process, we asked whether Cl-amidine has antioxidant properties. Here we show that colitis induced with azoxymethane via intraperitoneal injection + 2% dextran sulfate sodium in the drinking water is suppressed by Cl-amidine (also given in the drinking water). Inducible nitric oxide synthase, an inflammatory marker, was also downregulated in macrophages by Cl-amidine. Because epithelial cell DNA damage associated with colitis is at least in part a result of an oxidative burst from overactive leukocytes, we tested the hypothesis that Cl-amidine can inhibit leukocyte activation, as well as subsequent target epithelial cell DNA damage in vitro and in vivo. Results are consistent with this hypothesis, and because DNA damage is a procancerous mechanism, our data predict that Cl-amidine will not only suppress colitis, but we hypothesize that it may prevent colon cancer associated with colitis. PMID:25635139

  4. Inhibition of angiogenesis by S-adenosylmethionine

    SciTech Connect

    Sahin, Mehmet; Sahin, Emel; Guemueslue, Saadet; Erdogan, Abdullah; Gueltekin, Meral

    2011-04-29

    Highlights: {yields} Effects of S-adenosylmethionine (SAM) were investigated in endothelial cells. {yields} Our results showed that SAM decreased proliferation of endothelial cells. {yields} SAM influentially inhibited the percentage of cell migration. {yields} SAM probably stopped migration as independent from its effects on proliferation. {yields} SAM was shown to suppress in vitro angiogenesis. -- Abstract: Metastasis is a leading cause of mortality and morbidity in cancer. One of the steps in metastasis process is the formation of new blood vessels. Aberrant DNA methylation patterns are common in cancer cells. In recent studies, S-adenosylmethionine (SAM), which is a DNA methylating agent, has been found to have inhibitory effects on some carcinoma cells in vivo and in vitro. In the present study, we have used SAM to investigate whether it is effective against angiogenesis in vitro. Our results have shown that SAM can reduce the formation and organization of capillary-like structures of endothelial cells in tumoral environment. Besides, we have found SAM can block endothelial cell proliferation and the migration of cells towards growth factors-rich media. In conclusion, our study suggests that SAM may be used against angiogenesis as a natural bio-product.

  5. HDACIs and the inhibition of invasive potential

    PubMed Central

    Dent, Paul

    2013-01-01

    A major problem in the treatment of cancer and prolongation of patient survival is the dissemination of cells from a defined tumor site into a loco-regional disease and ultimately to full metastatic spread into distant organs. In the manuscript by Ierano et al. multiple chemically diverse histone deacetylase inhibitors (HDACIs) in tumor cell types of many diverse origins were shown to increase expression of the receptor CXCR4; a receptor whose expression promotes metastatic spread of tumor cells and that is correlated with a stage independent poor prognosis.1,2 The ligand of CXCR4, CXCL12, also called stromal cell-derived factor (SDF1), stimulates signaling through multiple pathways downstream of the CXCR4 receptor including SRC kinases, ERK1/2, and STAT3. Inhibition of SRC, ERK, or STAT3 can all suppress tumor cell migration and reduce the threshold at which tumor cells undergo apoptosis.3-8 The authors noted that despite increased CXCR4 expression following HDACI treatment, exogenous CXCL12 ligand had a reduced ability to stimulate cell signaling processes, with the phosphorylation of both SRC and STAT3 at activating sites declining. This resulted in less induced migration of HDACI-treated tumor cells. No studies were undertaken to determine whether HDACI-treated cells transduced to express activated forms of SRC or STAT3 or retained their invasive phenotype; however a loss of SRC and STAT3 signaling would predict for a less invasive phenotype. PMID:23974427

  6. Inhibition of immune functions by antiviral drugs.

    PubMed Central

    Heagy, W; Crumpacker, C; Lopez, P A; Finberg, R W

    1991-01-01

    Immune functions were evaluated in vitro for PBMC isolated from healthy donors and cultured with the antiviral agents, 3'-azido-3'-deoxythymidine (AZT), ribavirin, ganciclovir, 2'3'-dideoxyinosine (ddI), or acyclovir. To identify methods for assessing the effects of antiviral drugs on immune cells, the PBMC response to mitogens, Con A, or phytohemagglutinin was evaluated from measurements of [3H]thymidine and [14C]-leucine incorporation, cell growth, cellular RNA, DNA, and protein levels, and the PBMC proliferative cycle (i.e., progression from G0----G1----S----G2 + M). At clinically relevant concentrations, AZT, ribavirin, or ganciclovir diminished PBMC responsiveness to mitogen. The numbers of proliferating cells in G1, S, and G2 + M phases of the cell cycle, DNA content, and [3H]thymidine uptake were decreased in cultures treated with AZT, ribavirin, or ganciclovir. AZT or ribavirin but not ganciclovir reduced RNA and protein in the cultures and inhibited cell growth. Whereas AZT, ribavirin, or ganciclovir were antiproliferative, ddI or acyclovir had little, if any, effect on PBMC mitogenesis. The inhibitory effects of antivirals on immune cells may contribute to the immune deterioration observed in patients following prolonged use of the drugs. PMID:1904068

  7. High outgroup entitativity can inhibit intergroup retribution.

    PubMed

    Newheiser, Anna-Kaisa; Dovidio, John F

    2015-06-01

    Understanding the psychological processes that are involved in the perpetuation and escalation of intergroup conflict remains an important goal for intergroup relations research. In the present research, we examined perceived outgroup entitativity as a potential determinant of intergroup hostility. In intergroup conflict situations, high-entitative outgroups are perceived as particularly deserving of retribution; however, high-entitative outgroups are also perceived as efficacious and capable of retaliating successfully, suggesting that people may inhibit hostility against high-entitative (vs. low-entitative) outgroups that are in a position to retaliate. We tested this prediction in two studies. In Study 1, we manipulated intergroup provocation and outgroup entitativity, and found that higher negative mood predicted greater aggression against a low-entitative provoker outgroup, but failed to predict aggression against a high-entitative provoker outgroup that was plausibly in a position to retaliate. In Study 2, we held provocation constant while manipulating outgroup entitativity and the possibility of retaliation by the outgroup, and found that people acted in a retributive manner against a high-entitative provoker outgroup only when the outgroup was not in a position to retaliate. Implications for intergroup conflict are discussed. PMID:25066604

  8. Complement Activation and Inhibition in Retinal Diseases.

    PubMed

    Kleinman, Mark E; Ambati, Jayakrishna

    2016-01-01

    Within the past several decades, a brigade of dedicated researchers from around the world has provided essential insights into the critical niche of immune-mediated inflammation in the pathogenesis of age-related macular degeneration (AMD). Yet, the question has lingered as to whether disease-initiating events are more or less dependent on isolated immune-related responses, unimpeded inflammation, endogenous pathways of age-related cell senescence and oxidative stress, or any of the other numerous molecular derangements that have been identified in the natural history of AMD. There is now an abundant cache of data signifying immune system activation as an impetus in the pathogenesis of this devastating condition. Furthermore, recent rigorous investigations have revealed multiple inciting factors, including several important complement-activating components, thus creating a new array of disease-modulating targets for the research and development of molecular therapeutic interventions. While the precise in vivo effects of complement activation and inhibition in the progression and treatment of AMD remain to be determined, ongoing clinical trials of the first generation of complement-targeted therapeutics are hoped to yield critical data on the contribution of this pathway to the disease process. PMID:26501209

  9. Methylsulfonylmethane inhibits NLRP3 inflammasome activation.

    PubMed

    Ahn, Huijeong; Kim, Jeeyoung; Lee, Min-Jae; Kim, Young Jin; Cho, Young-Wook; Lee, Geun-Shik

    2015-02-01

    Methylsulfonylmethane (MSM) is an organosulfur compound and the health benefits associated with MSM include inflammation. Although MSM has been shown to have various physiological effects, no study has yet focused on inflammasome activation. The inflammasome is a multiprotein complex that serves as a platform for caspase 1-dependent proteolytic maturation and secretion of interleukin-1? (IL-1?). In this study, we tested the effect of MSM on inflammasome activation using mouse and human macrophages. In our results, MSM significantly attenuated NLRP3 inflammasome activation in lipopolysaccharide-primed macrophages, although it had no effect on NLCR4 or AIM2 inflammasome activation. Extracts of MSM-enriched vegetables presented the same inhibitory effect on NLRP3 inflammasome activation as MSM. MSM also attenuated the transcriptional expression of IL-1?, IL-1?, IL-6, and NLRP3. Taken together, these results show that MSM has anti-inflammatory characteristics, interrupts NLRP3 inflammasome activation, and inhibits pro-cytokine expression. We further confirmed the intracellular mechanism of MSM in relation to NLRP3 inflammasome activation, followed by comparison with that of DMSO. Both chemicals showed a synergic effect on anti-NLRP3 activation and attenuated production of mitochondrial reactive oxygen species (ROS). Thus, MSM is a selective inhibitor of NLRP3 inflammasome activation and can be developed as a supplement to control several metabolic disorders. PMID:25461402

  10. Inhibition of RAS in diabetic nephropathy

    PubMed Central

    Yacoub, Rabi; Campbell, Kirk N

    2015-01-01

    Diabetic kidney disease (DKD) is a progressive proteinuric renal disorder in patients with type 1 or type 2 diabetes mellitus. It is a common cause of end-stage kidney disease worldwide, particularly in developed countries. Therapeutic targeting of the renin–angiotensin system (RAS) is the most validated clinical strategy for slowing disease progression. DKD is paradoxically a low systematic renin state with an increased intrarenal RAS activity implicated in its pathogenesis. Angiotensin II (AngII), the main peptide of RAS, is not only a vasoactive peptide but functions as a growth factor, activating interstitial fibroblasts and mesangial and tubular cells, while promoting the synthesis of extracellular matrix proteins. AngII also promotes podocyte injury through increased calcium influx and the generation of reactive oxygen species. Blockade of the RAS using either angiotensin converting enzyme inhibitors, or angiotensin receptor blockers can attenuate progressive glomerulosclerosis in animal models, and slows disease progression in humans with DKD. In this review, we summarize the role of intrarenal RAS activation in the pathogenesis and progression of DKD and the rationale for RAS inhibition in this population. PMID:25926752

  11. PCSK9 inhibition in patients with hypercholesterolemia.

    PubMed

    Desai, Nihar R; Sabatine, Marc S

    2015-10-01

    Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease that plays an important role in modulating low-density lipoprotein cholesterol (LDL-C) levels by targeting LDL-C receptors for lysosomal degradation. Genetic association studies have demonstrated that loss-of-function mutations in PCSK9 are associated with low plasma LDL-C levels and a reduction in the incidence of adverse cardiovascular events. Monoclonal antibodies directed against PCSK9 have been developed and have been shown in phase 1, 2, and 3 trials to dramatically reduce LDL-C regardless of background lipid-lowering therapy, including in clinically challenging populations such as patients intolerant to statin therapy and those with familial hypercholesterolemia. To date, the clinical trials have not raised any significant safety concerns, with no appreciable excess of myalgias, elevation in aminotransferases, or other adverse events. Large, cardiovascular outcomes trials are underway to assess definitively the efficacy and safety of 3 monoclonal antibodies (evolocumab, alirocumab, and bococizumab), while additional non-monoclonal antibody approaches to inhibit PCSK9 continue in the early-phase development. PMID:25771732

  12. Inhibition of vascular permeability by antisense-mediated inhibition of plasma kallikrein and coagulation factor 12.

    PubMed

    Bhattacharjee, Gourab; Revenko, Alexey S; Crosby, Jeffrey R; May, Chris; Gao, Dacao; Zhao, Chenguang; Monia, Brett P; MacLeod, A Robert

    2013-06-01

    Hereditary angioedema (HAE) is a rare disorder characterized by recurrent, acute, and painful episodes of swelling involving multiple tissues. Deficiency or malfunction of the serine protease inhibitor C1 esterase inhibitor (C1-INH) results in HAE types 1 and 2, respectively, whereas mutations in coagulation factor 12 (f12) have been associated with HAE type 3. C1-INH is the primary inhibitor of multiple plasma cascade pathways known to be altered in HAE patients, including the complement, fibrinolytic, coagulation, and kinin-kallikrein pathways. We have selectively inhibited several components of both the kinin-kallikrein system and the coagulation cascades with potent and selective antisense oligonucleotides (ASOs) to investigate their relative contributions to vascular permeability. We have also developed ASO inhibitors of C1-INH and characterized their effects on vascular permeability in mice as an inducible model of HAE. Our studies demonstrate that ASO-mediated reduction in C1-INH plasma levels results in increased vascular permeability and that inhibition of proteases of the kinin-kallikrein system, either f12 or prekallikrein (PKK) reverse the effects of C1-INH depletion with similar effects on both basal and angiotensin converting enzyme (ACE) inhibitor-induced permeability. In contrast, inhibition of coagulation factors 11 (f11) or 7 (f7) had no effect. These results suggest that the vascular defects observed in C1-INH deficiency are dependent on the kinin-kallikrein system proteases f12 and PKK, and not mediated through the coagulation pathways. In addition, our results highlight a novel therapeutic modality that can potentially be employed prophylactically to prevent attacks in HAE patients. PMID:23582057

  13. Bee venom inhibits growth of human cervical tumors in mice.

    PubMed

    Lee, Hye Lim; Park, Sang Ho; Kim, Tae Myoung; Jung, Yu Yeon; Park, Mi Hee; Oh, Sang Hyun; Yun, Hye Seok; Jun, Hyung Ok; Yoo, Hwan Soo; Han, Sang-Bae; Lee, Ung Soo; Yoon, Joo Hee; Song, Min Jong; Hong, Jin Tae

    2015-03-30

    We studied whether bee venom (BV) inhibits cervical tumor growth through enhancement of death receptor (DR) expressions and inactivation of nuclear factor kappa B (NF-?B) in mice. In vivo study showed that BV (1 mg/kg) inhibited tumor growth. Similar inhibitory effects of BV on cancer growth in primary human cervical cancer cells were also found. BV (1-5 ?g/ml) also inhibited the growth of cancer cells, Ca Ski and C33Aby the induction of apoptotic cell death in a dose dependent manner. Agreed with cancer cell growth inhibition, expression of death receptors; FAS, DR3 and DR6, and DR downstream pro-apoptotic proteins including caspase-3 and Bax was concomitantly increased, but the NF-?B activity and the expression of Bcl-2 were inhibited by treatment with BV in tumor mice, human cancer cell and human tumor samples as well as cultured cancer cells. In addition, deletion of FAS, DR3 and DR6 by small interfering RNA significantly reversed BV-induced cell growth inhibitory effects as well as NF-?B inactivation. These results suggest that BV inhibits cervical tumor growth through enhancement of FAS, DR3 and DR6 expression via inhibition of NF-?B pathway. PMID:25730901

  14. Australine, a pyrrolizidine alkaloid that inhibits amyloglucosidase and glycoprotein processing

    SciTech Connect

    Tropea, J.E.; Molyneux, R.J.; Kaushal, G.P.; Pan, Y.T.; Mitchell, M.; Elbein, A.D. )

    1989-03-07

    Australine is a polyhydroxylated pyrrolizidine alkaloid that was isolated from the seeds of the Australian tree Castanospermum australe and characterized by NMR and X-ray diffraction analysis. Since swainsonine and catanospermine are polyhydroxylated indolizidine alkaloids that inhibit specific glycosidases, the authors tested australine against a variety of exoglycosidases to determine whether it would inhibit any of these enzymes. This alkaloid proved to be a good inhibitor of the {alpha}-glucosidase amyloglucosidase (50% inhibition at 5.8 {mu}M), but it did not inhibit {beta}-glucosidase, {alpha}- or {beta}-mannosidase, or {alpha}- or {beta}-galactosidase. The inhibition of amyloglucosidase was of a competitive nature. Australine also inhibited the glycoprotein processing enzyme glucosidase I, but had only slight activity toward glucosidase II. When incubated with cultured cells, this alkaloid inhibited glycoprotein processing at the glucosidase I step and caused the accumulation of glycoproteins with Glc{sub 3}Man{sub 7-9}(GlcNAc){sub 2}-oligosaccharides.

  15. Inhibition of Human Neutrophil Elastase by Pentacyclic Triterpenes

    PubMed Central

    Feng, Li; Liu, Xiaoyu; Zhu, Weiliang; Guo, Fujiang; YingchunWu; Wang, Rui; Chen, Kaixian; Huang, Cheng; Li, Yiming

    2013-01-01

    Scope Inhibiting human neutrophil elastase (HNE) is a promising strategy for treating inflammatory lung diseases, such as H1N1 and SARS virus infections. The use of sivelestat, the only clinically registered synthesized HNE inhibitor, is largely limited by its risk of organ toxicity because it irreversibly inhibits HNE. Therefore, potent reversible HNE inhibitors are promising alternatives to sivelestat. Methods and Results An in vitro HNE inhibition assay was employed to screen a series of triterpenes. Six pentacyclic triterpenes, but not tetracyclic triterpenes, significantly inhibited HNE. Of these pentacyclic triterpenes, ursolic acid exhibited the highest inhibitory potency (IC50?=?5.51 µM). The HNE inhibitory activity of ursolic acid was further verified using a mouse model of acute smoke-induced lung inflammation. The results of nuclear magnetic resonance and HNE inhibition kinetic analysis showed that the pentacyclic triterpenes competitively and reversibly inhibited HNE. Molecular docking experiments indicated that the molecular scaffold, 28-COOH, and a double bond at an appropriate location in the pentacyclic triterpenes are important for their inhibitory activity. Conclusion Our results provide insights into the effects of pentacyclic triterpenes on lung inflammatory actions through reversible inhibition of HNE activity. PMID:24376583

  16. Intentional inhibition in human action: the power of 'no'.

    PubMed

    Filevich, Elisa; Kühn, Simone; Haggard, Patrick

    2012-04-01

    The capacity to inhibit and withhold actions is a key feature of human cognition. Withholding action forms the basis of self-control, delayed gratification, social contracts, and trust in others. Most experimental studies of this function come from studying the processing of external stop signals. However, another important aspect of inhibition is 'will-power', i.e., intentional inhibitory control over one's own actions, in the absence of external countermanding signals. We review whether a concept of intentional inhibition is justified, and how it might differ from externally triggered inhibition. Further, we consider three types of neuroscientific evidence that can clarify the brain's mechanisms of inhibition: neuropsychology, neurostimulation and neuroimaging. Finally, we propose a model in which intentional inhibition, unlike externally triggered inhibition, is linked to representing longer range consequences of action decisions. We suggest that the human brain contains a 'neural brake' mechanism that blocks specific ongoing motor activity, and that this mechanism plays a key role in action decisions. PMID:22305996

  17. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine.

    PubMed

    Pakavathkumar, Prateep; Sharma, Gyanesh; Kaushal, Vikas; Foveau, Bénédicte; LeBlanc, Andrea C

    2015-01-01

    Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases. PMID:26400108

  18. Methylene Blue Inhibits Caspases by Oxidation of the Catalytic Cysteine

    PubMed Central

    Pakavathkumar, Prateep; Sharma, Gyanesh; Kaushal, Vikas; Foveau, Bénédicte; LeBlanc, Andrea C.

    2015-01-01

    Methylene blue, currently in phase 3 clinical trials against Alzheimer Disease, disaggregates the Tau protein of neurofibrillary tangles by oxidizing specific cysteine residues. Here, we investigated if methylene blue can inhibit caspases via the oxidation of their active site cysteine. Methylene blue, and derivatives, azure A and azure B competitively inhibited recombinant Caspase-6 (Casp6), and inhibited Casp6 activity in transfected human colon carcinoma cells and in serum-deprived primary human neuron cultures. Methylene blue also inhibited recombinant Casp1 and Casp3. Furthermore, methylene blue inhibited Casp3 activity in an acute mouse model of liver toxicity. Mass spectrometry confirmed methylene blue and azure B oxidation of the catalytic Cys163 cysteine of Casp6. Together, these results show a novel inhibitory mechanism of caspases via sulfenation of the active site cysteine. These results indicate that methylene blue or its derivatives could (1) have an additional effect against Alzheimer Disease by inhibiting brain caspase activity, (2) be used as a drug to prevent caspase activation in other conditions, and (3) predispose chronically treated individuals to cancer via the inhibition of caspases. PMID:26400108

  19. Inhibition of pinocytosis in rat embryo fibroblasts treated with monensin

    PubMed Central

    1982-01-01

    Rat embryo fibroblasts cultured in the presence of monensin exhibited an inhibited uptake of horseradish peroxidase. The inhibition was detected after 3 h, after which time the cells became increasingly vacuolated; the concentration of monensin required to inhibit pinocytosis (0.4 microM for half-maximum inhibition at 18 h) was similar to that found by others to inhibit secretion. Both the exchange of 5'-nucleotidase between the membranes of cytoplasmic organelles and the cell surface and the internalization of anti-5'-nucleotidase bound to the cell surface were inhibited by approximately 90% in monensin- treated cells. The effects of monensin were reversible: cells cultured first with monensin, and then in fresh medium, exhibited control levels of horseradish peroxidase uptake, exchange of 5'-nucleotidase, and internalization of anti-5'-nucleotidase bound to the cell surface. After monensin treatment, the median density of both galactosyl transferase and 5'-nucleotidase increased from 1.128 to 1.148, and the median density of both N-acetyl-beta-glucosaminidase and horseradish peroxidase taken up by endocytosis decreased from 1.194 to 1.160. The results indicate that monensin is a reversible inhibitor of pinocytosis and, presumably, therefore, of membrane recycling. They suggest that the inhibition of membrane recycling occurs at a step other than the fusion of pinocytic vesicles with lysosomes and is perhaps a consequence of an effect of the ionophore on the Golgi complex. PMID:6282896

  20. Mechanism of Feedback Allosteric Inhibition of ATP Phosphoribosyltransferase

    PubMed Central

    2012-01-01

    MtATP-phosphoribosyltransferase catalyzes the first and committed step in l-histidine biosynthesis in Mycobacterium tuberculosis and is therefore subjected to allosteric feedback regulation. Because of its essentiality, this enzyme is being studied as a potential target for novel anti-infectives. To understand the basis for its regulation, we characterized the allosteric inhibition using gel filtration, steady-state and pre-steady-state kinetics, and the pH dependence of inhibition and binding. Gel filtration experiments indicate that MtATP-phosphoribosyltransferase is a hexamer in solution, in the presence or absence of l-histidine. Steady-state kinetic studies demonstrate that l-histidine inhibition is uncompetitive versus ATP and noncompetitive versus PRPP. At pH values close to neutrality, a Kii value of 4 ?M was obtained for l-histidine. Pre-steady-state kinetic experiments indicate that chemistry is not rate-limiting for the overall reaction and that l-histidine inhibition is caused by trapping the enzyme in an inactive conformation. The pH dependence of binding, obtained by nuclear magnetic resonance, indicates that l-histidine binds better as the neutral ?-amino group. The pH dependence of inhibition (Kii), on the contrary, indicates that l-histidine better inhibits MtATP-phosphoribosytransferase with a neutral imidazole and an ionized ?-amino group. These results are combined into a model that accounts for the allosteric inhibition of MtATP-phosphoribosyltransferase. PMID:22989207

  1. Bee venom inhibits growth of human cervical tumors in mice

    PubMed Central

    Kim, Tae Myoung; Jung, Yu Yeon; Park, Mi Hee; Oh, Sang Hyun; Yun, Hye Seok; Jun, Hyung Ok; Yoo, Hwan Soo; Han, Sang-Bae; Lee, Ung Soo; Yoon, Joo Hee; Song, Min Jong; Hong, Jin Tae

    2015-01-01

    We studied whether bee venom (BV) inhibits cervical tumor growth through enhancement of death receptor (DR) expressions and inactivation of nuclear factor kappa B (NF-?B) in mice. In vivo study showed that BV (1 mg/kg) inhibited tumor growth. Similar inhibitory effects of BV on cancer growth in primary human cervical cancer cells were also found. BV (1–5 ?g/ml) also inhibited the growth of cancer cells, Ca Ski and C33Aby the induction of apoptotic cell death in a dose dependent manner. Agreed with cancer cell growth inhibition, expression of death receptors; FAS, DR3 and DR6, and DR downstream pro-apoptotic proteins including caspase-3 and Bax was concomitantly increased, but the NF-?B activity and the expression of Bcl-2 were inhibited by treatment with BV in tumor mice, human cancer cell and human tumor samples as well as cultured cancer cells. In addition, deletion of FAS, DR3 and DR6 by small interfering RNA significantly reversed BV-induced cell growth inhibitory effects as well as NF-?B inactivation. These results suggest that BV inhibits cervical tumor growth through enhancement of FAS, DR3 and DR6 expression via inhibition of NF-?B pathway. PMID:25730901

  2. Mechanism-based inhibition of cancer metastasis with (?)-epigallocatechin gallate

    SciTech Connect

    Takahashi, Atsushi; Graduate School of Science and Engineering, Saitama University, Saitama 338-8570; Green Tea Laboratory, Saitama Prefectural Agriculture and Forestry Research Center, Saitama 358-0042 ; Watanabe, Tatsuro; Mondal, Anupom; Suzuki, Kaori; Kurusu-Kanno, Miki; Li, Zhenghao; Yamazaki, Takashi; Graduate School of Science and Engineering, Saitama University, Saitama 338-8570 ; Fujiki, Hirota; Suganuma, Masami

    2014-01-03

    Highlights: •EGCG reduced cell motility of highly metastatic human lung cancer cells. •EGCG increased cell stiffness of the cells, indicating the inhibition of phenotypes of EMT. •EGCG inhibited expression of vimentin and Slug in the cells at the leading edge of scratch. •Treatment of M?CD increased cell stiffness, and inhibited cell motility and vimentin expression. •Inhibition of EMT phenotypes with EGCG is a mechanism-based inhibition of cancer metastasis. -- Abstract: Cell motility and cell stiffness are closely related to metastatic activity of cancer cells. (?)-Epigallocatechin gallate (EGCG) has been shown to inhibit spontaneous metastasis of melanoma cell line into the lungs of mice, so we studied the effects of EGCG on cell motility, cell stiffness, and expression of vimentin and Slug, which are molecular phenotypes of epithelial–mesenchymal transition (EMT). Treatments of human non-small cell lung cancer cell lines H1299 and Lu99 with 50 and 100 ?M EGCG reduced cell motility to 67.5% and 43.7% in H1299, and 71.7% and 31.5% in Lu99, respectively in in vitro wound healing assay. Studies on cell stiffness using atomic force microscope (AFM) revealed that treatment with 50 ?M EGCG increased Young’s modulus of H1299 from 1.24 to 2.25 kPa and that of Lu99 from 1.29 to 2.28 kPa, showing a 2-fold increase in cell stiffness, i.e. rigid elasticity of cell membrane. Furthermore, treatment with 50 ?M EGCG inhibited high expression of vimentin and Slug in the cells at a leading edge of scratch. Methyl-?-cyclodextrin, a reagent to deplete cholesterol in plasma membrane, showed inhibition of EMT phenotypes similar that by EGCG, suggesting that EGCG induces inhibition of EMT phenotypes by alteration of membrane organization.

  3. Pyridinylpyrimidines selectively inhibit human methionine aminopeptidase-1†

    PubMed Central

    Zhang, Pengtao; Yang, Xinye; Zhang, Feiran; Gabelli, Sandra B.; Wang, Renxiao; Zhang, Yihua; Bhat, Shridhar; Chen, Xiaochun; Furlani, Manuel; Amzel, L. Mario; Liu, Jun O.; Ma, Dawei

    2013-01-01

    Cellular protein synthesis is initiated with methionine in eukaryotes with few exceptions. Methionine aminopeptidases (MetAPs) which catalyze the process of N-terminal methionine excision are essential for all organisms. In mammals, type 2 MetAP (MetAP2) is known to be important for angiogenesis, while type 1 MetAP (MetAP1) has been shown to play a pivotal role in cell proliferation. Our previous high-throughput screening of a commercial compound library uncovered a novel class of inhibitors for both human MetAP1 (HsMetAP1) and human MetAP2 (HsMetAP2). This class of inhibitors contains a pyridinylpyrimidine core. To understand the structure-activity relationship (SAR) and to search for analogues of 2 with greater potency and higher HsMetAP1-selectivity, a total of fifty-eight analogues were acquired through either commercial source or by in-house synthesis and their inhibitory activities against HsMetAP1 and HsMetAP2 were determined. Through this systematic medicinal chemistry analysis, we have identified (1) 5-chloro-6-methyl-2-pyridin-2-ylpyrimidine as the minimum element for the inhibition of HsMetAP1; (2) 5?-chloro as the favored substituent on the pyridine ring for the enhanced potency against HsMetAP1; and (3) long C4 side chains as the essentials for higher HsMet AP1-selectivity. At the end of our SAR campaign, 25b, 25c, 26d and 30a–30c are among the most selective and potent inhibitors of purified HsMetAP1 reported to date. In addition, we also performed crystallographic analysis of one representative inhibitor (26d) in complex with N-terminally truncated HsMetAP1. PMID:23507151

  4. Inhibition of polyadenylation reduces inflammatory gene induction

    PubMed Central

    Kondrashov, Alexander; Meijer, Hedda A.; Barthet-Barateig, Adeline; Parker, Hannah N.; Khurshid, Asma; Tessier, Sarah; Sicard, Marie; Knox, Alan J.; Pang, Linhua; de Moor, Cornelia H.

    2012-01-01

    Cordycepin (3? deoxyadenosine) has long been used in the study of in vitro assembled polyadenylation complexes, because it terminates the poly(A) tail and arrests the cleavage complex. It is derived from caterpillar fungi, which are highly prized in Chinese traditional medicine. Here we show that cordycepin specifically inhibits the induction of inflammatory mRNAs by cytokines in human airway smooth muscle cells without affecting the expression of control mRNAs. Cordycepin treatment results in shorter poly(A) tails, and a reduction in the efficiency of mRNA cleavage and transcription termination is observed, indicating that the effects of cordycepin on 3? processing in cells are similar to those described in in vitro reactions. For the CCL2 and CXCL1 mRNAs, the effects of cordycepin are post-transcriptional, with the mRNA disappearing during or immediately after nuclear export. In contrast, although the recruitment of RNA polymerase II to the IL8 promoter is also unaffected, the levels of nascent transcript are reduced, indicating a defect in transcription elongation. We show that a reporter construct with 3? sequences from a histone gene is unaffected by cordycepin, while CXCL1 sequences confer cordycepin sensitivity to the reporter, demonstrating that polyadenylation is indeed required for the effect of cordycepin on gene expression. In addition, treatment with another polyadenyation inhibitor and knockdown of poly(A) polymerase ? also specifically reduced the induction of inflammatory mRNAs. These data demonstrate that there are differences in the 3? processing of inflammatory and housekeeping genes and identify polyadenylation as a novel target for anti-inflammatory drugs. PMID:23118416

  5. Inhibition of Inflammatory Arthritis Using Fullerene Nanomaterials

    PubMed Central

    Dellinger, Anthony L.; Cunin, Pierre; Lee, David; Kung, Andrew L.; Brooks, D. Bradford; Zhou, Zhiguo; Nigrovic, Peter A.; Kepley, Christopher L.

    2015-01-01

    Inflammatory arthritis (e.g. rheumatoid arthritis; RA) is a complex disease driven by the interplay of multiple cellular lineages. Fullerene derivatives have previously been shown to have anti-inflammatory capabilities mediated, in part, by their ability to prevent inflammatory mediator release by mast cells (MC). Recognizing that MC can serve as a cellular link between autoantibodies, soluble mediators, and other effector populations in inflammatory arthritis, it was hypothesized that fullerene derivatives might be used to target this inflammatory disease. A panel of fullerene derivatives was tested for their ability to affect the function of human skin-derived MC as well as other lineages implicated in arthritis, synovial fibroblasts and osteoclasts. It is shown that certain fullerene derivatives blocked Fc?R- and TNF-?-induced mediator release from MC; TNF-?-induced mediator release from RA synovial fibroblasts; and maturation of human osteoclasts. MC inhibition by fullerene derivatives was mediated through the reduction of mitochondrial membrane potential and Fc?R-mediated increases in cellular reactive oxygen species and NF-?B activation. Based on these in vitro data, two fullerene derivatives (ALM and TGA) were selected for in vivo studies using K/BxN serum transfer arthritis in C57BL/6 mice and collagen-induced arthritis (CIA) in DBA/1 mice. Dye-conjugated fullerenes confirmed localization to affected joints in arthritic animals but not in healthy controls. In the K/BxN moldel, fullerenes attenuated arthritis, an effect accompanied by reduced histologic inflammation, cartilage/bone erosion, and serum levels of TNF-?. Fullerenes remained capable of attenuating K/BxN arthritis in mast cell-deficient mice Cre-Master mice, suggesting that lineages beyond the MC represent relevant targets in this system. These studies suggest that fullerene derivatives may hold promise both as an assessment tool and as anti-inflammatory therapy of arthritis. PMID:25879437

  6. Volatile hydrocarbons inhibit methanogenic crude oil degradation

    PubMed Central

    Sherry, Angela; Grant, Russell J.; Aitken, Carolyn M.; Jones, D. Martin; Head, Ian M.; Gray, Neil D.

    2014-01-01

    Methanogenic degradation of crude oil in subsurface sediments occurs slowly, but without the need for exogenous electron acceptors, is sustained for long periods and has enormous economic and environmental consequences. Here we show that volatile hydrocarbons are inhibitory to methanogenic oil biodegradation by comparing degradation of an artificially weathered crude oil with volatile hydrocarbons removed, with the same oil that was not weathered. Volatile hydrocarbons (nC5–nC10, methylcyclohexane, benzene, toluene, and xylenes) were quantified in the headspace of microcosms. Aliphatic (n-alkanes nC12–nC34) and aromatic hydrocarbons (4-methylbiphenyl, 3-methylbiphenyl, 2-methylnaphthalene, 1-methylnaphthalene) were quantified in the total hydrocarbon fraction extracted from the microcosms. 16S rRNA genes from key microorganisms known to play an important role in methanogenic alkane degradation (Smithella and Methanomicrobiales) were quantified by quantitative PCR. Methane production from degradation of weathered oil in microcosms was rapid (1.1 ± 0.1 ?mol CH4/g sediment/day) with stoichiometric yields consistent with degradation of heavier n-alkanes (nC12–nC34). For non-weathered oil, degradation rates in microcosms were significantly lower (0.4 ± 0.3 ?mol CH4/g sediment/day). This indicated that volatile hydrocarbons present in the non-weathered oil inhibit, but do not completely halt, methanogenic alkane biodegradation. These findings are significant with respect to rates of biodegradation of crude oils with abundant volatile hydrocarbons in anoxic, sulphate-depleted subsurface environments, such as contaminated marine sediments which have been entrained below the sulfate-reduction zone, as well as crude oil biodegradation in petroleum reservoirs and contaminated aquifers. PMID:24765087

  7. Inhibiting efficiency of polymethylenebis-2,2-benzimidazoles

    SciTech Connect

    Starchak, V.G.; Sizova, O.I.; Krasovskii, A.N.

    1994-09-01

    The effect of various derivatives of polymethylenebis-2,2-benzimidazole on the corrosion and electrochemical behavior of steel in H{sub 2}S-containing acids has been studied. Pentamethylenebis-2,2-benzimidazole appeared to be the best inhibitor. The test compounds inhibit both electrochemical (anodic inhibition) and chemical corrosion. Stress corrosion tests also showed the inhibitors to be efficient. Rough estimates suggest that the blocking effect dominates over the energetic {Psi}{sub 1} and kinetic effects in the optimum mechanism of inhibition.

  8. Inhibition of gravitropism in oat coleoptiles by calcium chelation

    NASA Technical Reports Server (NTRS)

    Roux, S. J.

    1984-01-01

    Some cellular event necessary for gravitropism is inhibited by EGTA without interferring with the overall growth. Calcium relieves this inhibition and demonstrates both that inhibition is reversible and was probably due to a reduction in the ability to free calcium required for one or more at the transduction steps of gravitropism. At the near neutral pH used, EGTA is charged and would not be expected to readily cross the membrane. One of its primary effects, then, is probably the bringing of free calcium in the apoplastic space exterior to the cell membranes.

  9. Reciprocal inhibition between the muscles of the human forearm.

    PubMed Central

    Day, B L; Marsden, C D; Obeso, J A; Rothwell, J C

    1984-01-01

    Peripheral and central mechanisms of reciprocal inhibition between antagonist muscles in the forearm have been studied in ten human subjects. H reflexes were evoked in flexor muscles by stimulating the median nerve with single shocks at around motor threshold intensity. Peripheral inhibition of the flexor H reflex was produced by motor threshold stimulation with a single shock of the radial nerve supplying the extensor muscles. The conditioning radial nerve stimulus produced inhibition of the flexor H reflex consisting of three phases. In some individuals, an H reflex could be evoked in extensor muscles of the forearm. Stimulation of the median nerve produced inhibition of the extensor H reflex with a similar time course to that from extensors to flexors. The first phase of inhibition was apparent when the test median nerve shock was given from 1 ms before to 3 ms after the conditioning radial nerve shock. It was abrupt in onset and short in duration and could be evoked with a conditioning stimulus intensity as low as 0.75 X motor threshold. The second and third phases of inhibition were evident when the conditioning radial nerve stimulus preceded the median nerve test shock by 5 to 50, and 50 to 500 ms respectively. The characteristics of these later phases of inhibition are to be the subject of a separate report. The difference in timing of the peak initial short-latency inhibition from extensor to flexor and from flexor to extensor muscles enabled an estimate to be made of the central synaptic delay of the inhibitory process. This method yielded a central delay of 0.95 ms in excess of that of the H reflex. We conclude that the first phase of inhibition is mediated via large group I afferents acting through a single inhibitory interneurone . Central inhibition of the flexor H reflex was demonstrated with the radial nerve anaesthetized by injection of local anaesthetic at the elbow. Subjects were asked to try to contract the paralysed extensor muscles. Under this condition, attempted voluntary wrist extension inhibited the flexor H reflex even though no movement occurred. A shock was delivered to the radial nerve at a site proximal to the anaesthetic block. When the shock was applied in conjunction with an attempted voluntary contraction of the paralysed extensor muscles, the depth of inhibition was greater than that predicted from the effect of either a shock or a willed contraction acting independently.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:6737302

  10. Investigtion of the metabolic inhibition observed in solid-substrate cultivation of Clostidium thermocellum on avicel

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Clostridium thermocellum exhibits premature metabolic inhibition during solid-substrate cultivation on Avicel, but the reason for the inhibition is not well understood. Inhibition was investigated by comparing three different cultivation techniques; submerged fermentation (SmF), solid substrate cult...

  11. Irreversible inhibition of RANK expression as a possible mechanism for IL-3 inhibition of RANKL-induced osteoclastogenesis

    SciTech Connect

    Khapli, Shruti M.; Tomar, Geetanjali B.; Barhanpurkar, Amruta P.; Gupta, Navita; Yogesha, S.D.; Pote, Satish T.; Wani, Mohan R.

    2010-09-03

    Research highlights: {yields} IL-3 inhibits receptor activator of NF-{kappa}B ligand (RANKL)-induced osteoclastogenesis. {yields} IL-3 inhibits RANKL-induced JNK activation. {yields} IL-3 down-regulates expression of c-Fos and NFATc1 transcription factors. {yields} IL-3 down-regulates RANK expression posttranscriptionally and irreversibly. {yields} IL-3 inhibits in vivo RANK expression. -- Abstract: IL-3, a cytokine secreted by activated T lymphocytes, stimulates the proliferation, differentiation and survival of pluripotent hematopoietic stem cells. In this study, we investigated the mechanism of inhibitory action of IL-3 on osteoclast differentiation. We show here that IL-3 significantly inhibits receptor activator of NF-{kappa}B (RANK) ligand (RANKL)-induced activation of c-Jun N-terminal kinase (JNK). IL-3 down-regulates expression of c-Fos and nuclear factor of activated T cells (NFATc1) transcription factors. In addition, IL-3 down-regulates RANK expression posttranscriptionally in both purified osteoclast precursors and whole bone marrow cells. Furthermore, the inhibitory effect of IL-3 on RANK expression was irreversible. Interestingly, IL-3 inhibits in vivo RANK expression in mice. Thus, we provide the first evidence that IL-3 irreversibly inhibits RANK expression that results in inhibition of important signaling molecules induced by RANKL.

  12. Inhibition of auxin movement from the shoot into the root inhibits lateral root development in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Reed, R. C.; Brady, S. R.; Muday, G. K.

    1998-01-01

    In roots two distinct polar movements of auxin have been reported that may control different developmental and growth events. To test the hypothesis that auxin derived from the shoot and transported toward the root controls lateral root development, the two polarities of auxin transport were uncoupled in Arabidopsis. Local application of the auxin-transport inhibitor naphthylphthalamic acid (NPA) at the root-shoot junction decreased the number and density of lateral roots and reduced the free indoleacetic acid (IAA) levels in the root and [3H]IAA transport into the root. Application of NPA to the basal half of or at several positions along the root only reduced lateral root density in regions that were in contact with NPA or in regions apical to the site of application. Lateral root development was restored by application of IAA apical to NPA application. Lateral root development in Arabidopsis roots was also inhibited by excision of the shoot or dark growth and this inhibition was reversible by IAA. Together, these results are consistent with auxin transport from the shoot into the root controlling lateral root development.

  13. Cyclooxygenase inhibitors inhibit antibody response through interference with MAPK/ERK pathways and BLIMP-1 inhibition.

    PubMed

    Purssell, E

    2014-09-01

    Fever is a common symptom of illness in children, and although not harmful in itself, fever and its associated symptoms are often treated with antipyretic drugs. A number of national and other guidelines now recommend against their routine use; a conclusion that was initially supported by a study showing that the prophylactic use of paracetamol might reduce antibody response to some vaccine antigens, although data from booster vaccinations are more equivocal. Although in vivo data on the cause of this inhibition are scarce, in vitro data suggests that the cause may be due to inhibition of the mitogen activated protein kinase/extracellular regulated protein kinase pathways, and a subsequent reduction in the process of plasma cell differentiation at the beginning of the antibody response. This suggests that in high-risk patients these drugs could be avoided in the early part of an infection when plasma-cell differentiation is occurring. More data are needed to define this period; until then existing data support the recommendation against the routine use of these drugs. PMID:25012778

  14. Inhibition of protein-peptide interactions by small molecules 

    E-print Network

    Yen, Li-Hsuan

    2014-11-27

    In all kinds of disease models, many proteins involved in protein-protein interactions (PPIs) are mutated and do not function properly. The important role of PPIs in disease makes the design of small molecule inhibition ...

  15. Glycinergic inhibition tunes coincidence detection in the auditory brainstem

    PubMed Central

    Myoga, Michael H.; Lehnert, Simon; Leibold, Christian; Felmy, Felix; Grothe, Benedikt

    2014-01-01

    Neurons in the medial superior olive (MSO) detect microsecond differences in the arrival time of sounds between the ears (interaural time differences or ITDs), a crucial binaural cue for sound localization. Synaptic inhibition has been implicated in tuning ITD sensitivity, but the cellular mechanisms underlying its influence on coincidence detection are debated. Here we determine the impact of inhibition on coincidence detection in adult Mongolian gerbil MSO brain slices by testing precise temporal integration of measured synaptic responses using conductance-clamp. We find that inhibition dynamically shifts the peak timing of excitation, depending on its relative arrival time, which in turn modulates the timing of best coincidence detection. Inhibitory control of coincidence detection timing is consistent with the diversity of ITD functions observed in vivo and is robust under physiologically relevant conditions. Our results provide strong evidence that temporal interactions between excitation and inhibition on microsecond timescales are critical for binaural processing. PMID:24804642

  16. Flagging Drugs That Inhibit the Bile Salt Export Pump.

    PubMed

    Montanari, Floriane; Pinto, Marta; Khunweeraphong, Narakorn; Wlcek, Katrin; Sohail, M Imran; Noeske, Tobias; Boyer, Scott; Chiba, Peter; Stieger, Bruno; Kuchler, Karl; Ecker, Gerhard F

    2016-01-01

    The bile salt export pump (BSEP) is an ABC-transporter expressed at the canalicular membrane of hepatocytes. Its physiological role is to expel bile salts into the canaliculi from where they drain into the bile duct. Inhibition of this transporter may lead to intrahepatic cholestasis. Predictive computational models of BSEP inhibition may allow for fast identification of potentially harmful compounds in large databases. This article presents a predictive in silico model based on physicochemical descriptors that is able to flag compounds as potential BSEP inhibitors. This model was built using a training set of 670 compounds with available BSEP inhibition potencies. It successfully predicted BSEP inhibition for two independent test sets and was in a further step used for a virtual screening experiment. After in vitro testing of selected candidates, a marketed drug, bromocriptin, was identified for the first time as BSEP inhibitor. This demonstrates the usefulness of the model to identify new BSEP inhibitors and therefore potential cholestasis perpetrators. PMID:26642869

  17. Conceptual Tempo and Inhibition of Movement in Black Preschool Children

    ERIC Educational Resources Information Center

    Harrison, Algea; Nadelman, Lorraine

    1972-01-01

    Objectives of this study were to attempt to classify preschool children on conceptual tempo, to investigate a relationship between conceptual tempo and ability to inhibit movement, and to investigate the relationship of intelligence to both dimensions. (Authors)

  18. Inhibition of acidic iron corrosion by. gamma. -irradiated 2-mercaptobenzimidazole

    SciTech Connect

    Makovei, G.L.; Ushakov, V.G.; Bagin, V.K.; Shemshei, V.P.

    1987-01-01

    The authors report on the corrosion inhibition of St 3 steel in hydrochloric acid by 2-mercaptobenzimidazole previously gamma-irradiated from a cobalt 60 source over an absorbed dose range of 0.25-50 MGy. The electrochemical corrosion characteristics of the steel inhibited by both irradiated and unirradiated quantities of the inhibitor were determined under controlled conditions. The possible effects of gamma radiation on the inhibitor molecules was explored by taking their ultraviolet and infrared spectra. The authors postulate that the gamma radiation can split the -SH group from the molecule to form free sulfur in the inhibitor solution and alter the inhibitor from the thiol to the thione form. The radiation-induced accumulation of the thione form, whose inhibitive action is due to highly negative pi-electron population density at the sulfur atom, gives the irradiated imidazole consistently good inhibitive properties.

  19. Noninvasive optical inhibition with a red-shifted microbial rhodopsin

    E-print Network

    Chuong, Amy (Amy S.)

    2015-01-01

    Optogenetic inhibition of neurons enables the causal assessment of their contributions to brain functions, but a limit to the utility of optogenetic modulation is the quantity of neural tissue that can be successfully ...

  20. Noninvasive optical inhibition with a red-shifted microbial rhodopsin

    E-print Network

    Miri, Mitra L.

    Optogenetic inhibition of the electrical activity of neurons enables the causal assessment of their contributions to brain functions. Red light penetrates deeper into tissue than other visible wavelengths. We present a ...

  1. Biodiversity inhibits parasites: Broad evidence for the dilution effect

    E-print Network

    Rohr, Jason

    Biodiversity inhibits parasites: Broad evidence for the dilution effect David J. Civitello1 the mechanisms that shape outbreaks. Simultaneously, human activ- ities are drastically reducing biodiversity. These concurrent pat- terns have prompted repeated suggestions that biodiversity and disease are linked

  2. Prolegomenon to an investigation of inhibition in design

    E-print Network

    Lark, Michael (Michael Andrew), 1965-

    2001-01-01

    This thesis is a preliminary investigation of the phenomenon of inhibition in the design process. My interest stems from observations of the vagaries of my own success as a designer. Sometimes things have gone well, or ...

  3. Behavioural inhibition: is it a risk factor for anxiety?

    PubMed

    Lahat, Ayelet; Hong, Melanie; Fox, Nathan A

    2011-06-01

    Behavioural inhibition is a stable temperamental trait that is identifiable during infancy and toddlerhood and is characterized by fearful reactivity to novelty. Children identified as behaviourally inhibited have been shown to be at increased risk for developing anxiety disorders such as social phobia. The current review addresses the link between behavioural inhibition and the risk for developing anxiety disorders. Research suggests that this risk may be modulated by a number of extrinsic and intrinsic factors. Extrinsic factors include particular parental beliefs, parenting styles, and childrearing contexts. Intrinsic factors include executive function capacities such as attention bias, attention shifting, inhibitory control, and self-monitoring. In the present paper we review the contribution of these factors to the development of anxiety in behaviourally inhibited children. PMID:21923226

  4. A MATHEMATICAL MODEL OF HPPD INHIBITION. Mathematical Medicine Study Group

    E-print Network

    Derks, Gianne

    in the breakdown (catabolism) of excess tyrosine, an amino acid, in the body of mammals. The inhibition of HPPD can catabolism pathway. In plants the same enzyme has a completely different role, it is essential

  5. Noninvasive optical inhibition with a red-shifted microbial rhodopsin

    PubMed Central

    Chuong, Amy S; Miri, Mitra L; Busskamp, Volker; Matthews, Gillian A C; Acker, Leah C; Sørensen, Andreas T; Young, Andrew; Klapoetke, Nathan C; Henninger, Mike A; Kodandaramaiah, Suhasa B; Ogawa, Masaaki; Ramanlal, Shreshtha B; Bandler, Rachel C; Allen, Brian D; Forest, Craig R; Chow, Brian Y; Han, Xue; Lin, Yingxi; Tye, Kay M; Roska, Botond; Cardin, Jessica A; Boyden, Edward S

    2014-01-01

    Optogenetic inhibition of the electrical activity of neurons enables the causal assessment of their contributions to brain functions. Red light penetrates deeper into tissue than other visible wavelengths. We present a red-shifted cruxhalorhodopsin, Jaws, derived from Haloarcula (Halobacterium) salinarum (strain Shark) and engineered to result in red light–induced photocurrents three times those of earlier silencers. Jaws exhibits robust inhibition of sensory-evoked neural activity in the cortex and results in strong light responses when used in retinas of retinitis pigmentosa model mice. We also demonstrate that Jaws can noninvasively mediate transcranial optical inhibition of neurons deep in the brains of awake mice. The noninvasive optogenetic inhibition opened up by Jaws enables a variety of important neuroscience experiments and offers a powerful general-use chloride pump for basic and applied neuroscience. PMID:24997763

  6. Functional inhibition of UQCRB suppresses angiogenesis in zebrafish

    SciTech Connect

    Cho, Yoon Sun; Jung, Hye Jin; Seok, Seung Hyeok; Payumo, Alexander Y.; Chen, James K.; Kwon, Ho Jeong

    2013-04-19

    Highlights: ? This is the first functional characterization of UQCRB in vivo model. ? Angiogenesis is inhibited with UQCRB loss of function in zebrafish. ? UQCRB is introduced as a prognostic marker for mitochondria- and angiogenesis-related diseases. -- Abstract: As a subunit of mitochondrial complex III, UQCRB plays an important role in complex III stability, electron transport, and cellular oxygen sensing. Herein, we report UQCRB function regarding angiogenesis in vivo with the zebrafish (Danio rerio). UQCRB knockdown inhibited angiogenesis in zebrafish leading to the suppression of VEGF expression. Moreover, the UQCRB-targeting small molecule terpestacin also inhibited angiogenesis and VEGF levels in zebrafish, supporting the role of UQCRB in angiogenesis. Collectively, UQCRB loss of function by either genetic and pharmacological means inhibited angiogenesis, indicating that UQCRB plays a key role in this process and can be a prognostic marker of angiogenesis- and mitochondria-related diseases.

  7. Axonal conduction block as a novel mechanism of prepulse inhibition

    PubMed Central

    Lee, A. H.; Megalou, E. V.; Wang, J.; Frost, W.N.

    2012-01-01

    In prepulse inhibition (PPI), the startle response to a strong, unexpected stimulus is diminished if shortly preceded by the onset of a different stimulus. Because deficits in this inhibitory gating process are a hallmark feature of schizophrenia and certain other psychiatric disorders, the mechanisms underlying PPI are of significant interest. We previously used the invertebrate model system Tritonia diomedea to identify the first cellular mechanism for PPI–presynaptic inhibition of transmitter release from the afferent neurons (S-cells) mediating the startle response. Here we report the involvement of a second, more powerful PPI mechanism in Tritonia: prepulse-elicited conduction block of action potentials traveling in the startle pathway caused by identified inhibitory interneurons activated by the prepulse. This example of axo-axonic conduction block–neurons in one pathway inhibiting the propagation of action potentials in another–represents a novel and potent mechanism of sensory gating in prepulse inhibition. PMID:23115164

  8. Optical inhibition of motor nerve and muscle activity

    E-print Network

    Liske, Holly

    Introduction: There is no therapeutic approach that provides precise and rapidly reversible inhibition of motor nerve and muscle activity for treatment of spastic hypertonia. Methods: We used optogenetics to demonstrate ...

  9. Spectroscopic analysis of urinary calculi and inhibition of their growth

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Durrer, William; Govani, Jayesh; Reza, Layra; Pinales, Luis

    2009-10-01

    We present here a study of kidney stone formation and growth inhibition based on a traditional medicine approach with Aquatica Lour (RAL) herbal extracts. Kidney stone material systems were synthesized in vitro using a simplified single diffusion gel growth technique. With the objective of revealing the mechanism of inhibition of calculi formation by RAL extracts, samples prepared without the presence of extract, and with the presence of extract, were analyzed using Raman, photoluminescence, and XPS. The unexpected presence of Zn revealed by XPS in a sample prepared with RAL provides an explanation for the inhibition process, and also explains the dramatic reflectance of incident light observed in attempts to obtain infrared transmission data. Raman data are consistent with the binding of the inhibitor to the oxygen of the kidney stone. Photoluminescence data corroborate with the other results to provide additional evidence of Zn-related inhibition.

  10. Pain inhibits pain; human brainstem mechanisms.

    PubMed

    Youssef, A M; Macefield, V G; Henderson, L A

    2016-01-01

    Conditioned pain modulation is a powerful analgesic mechanism, occurring when a painful stimulus is inhibited by a second painful stimulus delivered at a different body location. Reduced conditioned pain modulation capacity is associated with the development of some chronic pain conditions and the effectiveness of some analgesic medications. Human lesion studies show that the circuitry responsible for conditioned pain modulation lies within the caudal brainstem, although the precise nuclei in humans remain unknown. We employed brain imaging to determine brainstem sites responsible for conditioned pain modulation in 54 healthy individuals. In all subjects, 8 noxious heat stimuli (test stimuli) were applied to the right side of the mouth and brain activity measured using functional magnetic resonance imaging. This paradigm was then repeated. However, following the fourth noxious stimulus, a separate noxious stimulus, consisting of an intramuscular injection of hypertonic saline into the leg, was delivered (conditioning stimulus). During this test and conditioning stimulus period, 23 subjects displayed conditioned pain modulation analgesia whereas 31 subjects did not. An individual's analgesic ability was not influenced by gender, pain intensity levels of the test or conditioning stimuli or by psychological variables such as pain catastrophizing or fear of pain. Brain images were processed using SPM8 and the brainstem isolated using the SUIT toolbox. Significant increases in signal intensity were determined during each test stimulus and compared between subjects that did and did not display CPM analgesia (p<0.05, small volume correction). The expression of analgesia was associated with reduction in signal intensity increases during each test stimulus in the presence of the conditioning stimulus in three brainstem regions: the caudalis subdivision of the spinal trigeminal nucleus, i.e., the primary synapse, the region of the subnucleus reticularis dorsalis and in the dorsolateral pons in the region of the parabrachial nucleus. Furthermore, the magnitudes of these signal reductions in all three brainstem regions were significantly correlated to analgesia magnitude. Defining conditioned pain modulation circuitry provides a framework for the future investigations into the neural mechanisms responsible for the maintenance of persistent pain conditions thought to involve altered analgesic circuitry. PMID:26343321

  11. Promoting and inhibiting tunneling via nuclear motions.

    PubMed

    Császár, Attila G; Furtenbacher, Tibor

    2015-12-23

    Accurate, experimental rotational-vibrational energy levels determined via the MARVEL (Measured Active Rotational-Vibrational Energy Levels) algorithm and published recently for the symmetric-top (14)NH3 molecule in J. Quant. Spectrosc. Radiat. Transfer, 2015, 116, 117-130 are analyzed to unravel the promoting and inhibiting effects of vibrations and rotations on the tunneling splittings of the corresponding symmetric (s) and antisymmetric (a) rovibrational energy level pairs. The experimental transition data useful from the point of view of the present analysis cover the range 0.7-7000 cm(-1), sufficiently detailed rovibrational energy sets worth analyzing are available for 20 vibrational bands. The highest J value, where J stands for the rotational quantum number, within the experimental dataset employed is 30. Coupling of the "umbrella" motion of (14)NH3 with other vibrational degrees of freedom has only a minor effect on the a-s tunneling splitting characterizing the ground vibrational state, 0.79436(70) cm(-1). In the majority of the cases rotation around the C3 axis increases, while rotation around the two perpendicular axes decreases the tunneling splittings. For example, for the pair of vibrational ground states, 0(+) and 0(-), the tunneling splitting basically disappears at around J = 25 for the (J,K) = (J,1) states, where K = |k| is the usual quantum number characterizing the projection of the rotational angular momentum on the principal axis. The tunneling splittings, defined as energy differences E(a) - E(s) of corresponding energy level pairs, as a function of J and K show a very regular behavior for the ground state (GS) and the n?2 bands. For the other bands investigated exceptions from a regular behavior do occur, especially for bands characterized by degenerate vibrations, and occasionally the data available are not sufficient to arrive at definitive conclusions. The most irregular behavior is observed for rotational states characterized by the k - l = 3n rule (l is the vibrational angular momentum quantum number), with n = 0, 1, 2,… High-quality, variationally computed rovibrational data support all the conclusions of this study based on experimental energy levels. PMID:26660142

  12. Metal interactions in carcinogenesis: enhancement, inhibition

    PubMed Central

    Nordberg, Gunnar F.; Andersen, Ole

    1981-01-01

    Metals constitute a fundamentally important part of the total human environment. Since human exposure often involves complex mixtures of metal compounds and, possibly, organic compounds which may be carcinogenic per se, interactions between these compounds may add significantly to human cancer risk. Our present knowledge about these kinds of interactions is very limited. The best investigated area is benzo(a)pyrene (BP)-metal oxide particle interactions in respiratory carcinogenesis in the hamster. Metal oxide particles were also shown to modify the carcinogenic effect of nitrosamines. Several reports describe experiments in which selenium compounds exerted a generally anticarcinogenic and antimutagenic activity. Inorganic arsenic compounds, which are accepted to be carcinogenic in man, have so far been negative in animal experiments except for one recent suggested report. Several authors have, however, suggested that these compounds may act as cocarcinogens due to their inhibition of DNA repair, although animal experiments to demonstrate a cocarcinogenic effect of arsenic compounds have been negative so far, except for one preliminary report. The concentration of zinc in the diet seemed to influence both transplanted tumor growth and the carcinogenicity of several organic compounds, and the possibility of a correlation between dietary zinc and certain cancer forms in man has been suggested. Protection against development of Leydigiomas usually induced by cadmium injection was afforded by simultaneous injection of zinc salts. Nickel carcinogenesis has been reported to be antagonized by manganese, and synergism between Ni and organic carcinogens, e.g. BP, has been demonstrated. There is no firm evidence that lead may be a cocarcinogen, although some limited experimental evidence is available. Oxidizing agents have been demonstrated to increase, and reducing agents to antagonize, the mutagenic effect of chromium compounds in vitro. The content of carcinogenic and other metals in asbestos has been suggested to modify the carcinogenic properties of asbestos. Since much of the information available at present is suggestive, further research on these interactions as well as other possible interactions in metal carcinogenesis is needed. Studies should be made both in well defined in vitro systems and in relevant animal models. PMID:7023935

  13. Proliferative and toxic effects of ultraviolet light and inflammation on epidermal pigment cells

    SciTech Connect

    Nordlund, J.J.; Ackles, A.E.; Traynor, F.F.

    1981-10-01

    The ear of the mouse is useful for studying the effects of ultraviolet light on epidermal pigment cells. The quantity of light penetrating into the skin causing an inflammatory response can be assessed easily by measuring with an engineering calipers the swelling of the ear. The inflammatory response of the ear exhibits a linear relationship to the dose of light delivered. We observed that doses of shortwave ultraviolet light which are noninflammatory when repeated at daily intervals induce moderate to severe inflammation. Small doses of psoralen and prolonged exposure to UVA (PUVA) were more inflammatory than larger amounts of psoralen and short exposure to light. Doses of shortwave ultraviolet light and PUVA which produce only a minimal inflammation of the skin stimulate the proliferation of epidermal melanocytes. In contrast, PUVA in doses sufficiently large to cause a marked inflammatory reaction in the skin seems injurious to pigment cells and kills them or causes only a minimal proliferative response. The inflammatory reaction itself does not seem to stimulate or inhibit the proliferation of melanocytes. Prostaglandins A, E, and F2 alpha have no effect on the proliferation of epidermal pigment cells. In contrast, dimethyl sulfoxide (DMSO) and allergic contact dermatitis increase the numerical density of pigment cells. Steroids may block the function of the enzyme tyrosinase. Our experiments indicate that pigment cells, like many other varieties of cells, are susceptible to injury and can be killed at least by large doses of PUVA.

  14. 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 ?-melanocyte stimulating hormone (?-MSH)-stimulated melanin formation in intact B16 melanoma cells.

  15. Fluoride inhibits the antimicrobial peroxidase systems in human whole saliva.

    PubMed

    Hannuksela, S; Tenovuo, J; Roger, V; Lenander-Lumikari, M; Ekstrand, J

    1994-01-01

    Fluoride (F-) ions at concentrations present in vivo at the plaque/enamel interface (0.05-10 mM) inhibited the activities of lactoperoxidase (LP), myeloperoxidase (MP) and total salivary peroxidase (TSP) in a pH- and dose-dependent way. The inhibition was observed only at pH < or = 6.5 and with F- concentrations > or = 0.1 mM. At pH 5.5 LP activity was inhibited by 85% and MP by 34% with 10 mM F-. TSP activity was also inhibited only at low pH (5.5) by approximately 25%. Furthermore, the generation of the actual antimicrobial agent in vivo, hypothiocyanite (HOSCN/OSCN-), of the oral peroxidase systems was inhibited by F-, again at low pH (5.0-5.5) both in buffer (by 45%) and in saliva (by 15%). This inhibition was observed only with the highest F- concentrations studied (5-10 mM). Fluoridated toothpaste (with 0.10 or 0.14% F) mixed with saliva did not inhibit TSP or HOSCN/OSCN- generation. This may have been due to the 'buffering' effect of toothpaste which did not allow salivary pH to drop below 5.9. We conclude that the F- ions in acidic fluoride products, e.g. in gels or varnishes (but not in toothpastes), may have the potential to locally inhibit the generation of a nonimmune host defense factor, HOSCN/OSCN/SCN-, produced by oral peroxidase systems. The possible clinical significance of this finding remains to be shown. PMID:7850846

  16. Novel Antimicrobial Peptides That Inhibit Gram Positive Bacterial Exotoxin Synthesis

    PubMed Central

    Merriman, Joseph A.; Nemeth, Kimberly A.; Schlievert, Patrick M.

    2014-01-01

    Gram-positive bacteria, such as Staphylococcus aureus, cause serious human illnesses through combinations of surface virulence factors and secretion of exotoxins. Our prior studies using the protein synthesis inhibitor clindamycin and signal transduction inhibitors glycerol monolaurate and ?-globin and ?-globin chains of hemoglobin indicate that their abilities to inhibit exotoxin production by S. aureus are separable from abilities to inhibit growth of the organism. Additionally, our previous studies suggest that inhibition of exotoxin production, in absence of ability to kill S. aureus and normal flora lactobacilli, will prevent colonization by pathogenic S. aureus, while not interfering with lactobacilli colonization. These disparate activities may be important in development of novel anti-infective agents that do not alter normal flora. We initiated studies to explore the exotoxin-synthesis-inhibition activity of hemoglobin peptides further to develop potential agents to prevent S. aureus infections. We tested synthesized ?-globin chain peptides, synthetic variants of ?-globin chain peptides, and two human defensins for ability to inhibit exotoxin production without significantly inhibiting S. aureus growth. All of these peptides were weakly or not inhibitory to bacterial growth. However, the peptides were inhibitory to exotoxin production with increasing activity dependent on increasing numbers of positively-charged amino acids. Additionally, the peptides could be immobilized on agarose beads or have amino acid sequences scrambled and still retain exotoxin-synthesis-inhibition. The peptides are not toxic to human vaginal epithelial cells and do not inhibit growth of normal flora L. crispatus. These peptides may interfere with plasma membrane signal transduction in S. aureus due to their positive charges. PMID:24748386

  17. Oxygen-induced inhibition of silicon-on-insulator dewetting

    SciTech Connect

    Curiotto, S.; Leroy, F.; Cheynis, F.; Müller, P.

    2014-02-10

    We report that solid state dewetting of Si thin film on SiO{sub 2} can be reversibly inhibited by exposing the Si surface to a partial pressure of dioxygen (?10{sup ?7}Torr) at high temperature (?1100K). Coupling in situ Low-Energy Electron Microscopy and ex situ atomic force microscopy we propose that the pinning of the contact line induced by the presence of small amounts of silicon oxide is the main physical process that inhibits the dewetting.

  18. Alpha oscillatory correlates of motor inhibition in the aged brain

    PubMed Central

    Bönstrup, Marlene; Hagemann, Julian; Gerloff, Christian; Sauseng, Paul; Hummel, Friedhelm C.

    2015-01-01

    Exerting inhibitory control is a cognitive ability mediated by functions known to decline with age. The goal of this study is to add to the mechanistic understanding of cortical inhibition during motor control in aged brains. Based on behavioral findings of impaired inhibitory control with age we hypothesized that elderly will show a reduced or a lack of EEG alpha-power increase during tasks that require motor inhibition. Since inhibitory control over movements has been shown to rely on prior motor memory formation, we investigated cortical inhibitory processes at two points in time—early after learning and after an overnight consolidation phase and hypothesized an overnight increase of inhibitory capacities. Young and elderly participants acquired a complex finger movement sequence and in each experimental session brain activity during execution and inhibition of the sequence was recorded with multi-channel EEG. We assessed cortical processes of sustained inhibition by means of task-induced changes of alpha oscillatory power. During inhibition of the learned movement, young participants showed a significant alpha power increase at the sensorimotor cortices whereas elderly did not. Interestingly, for both groups, the overnight consolidation phase improved up-regulation of alpha power during sustained inhibition. This points to deficits in the generation and enhancement of local inhibitory mechanisms at the sensorimotor cortices in aged brains. However, the alpha power increase in both groups implies neuroplastic changes that strengthen the network of alpha power generation over time in young as well as elderly brains. PMID:26528179

  19. Adenosine inhibits glutamatergic input to basal forebrain cholinergic neurons

    PubMed Central

    Hawryluk, J. M.; Ferrari, L. L.; Keating, S. A.

    2012-01-01

    Adenosine has been proposed as an endogenous homeostatic sleep factor that accumulates during waking and inhibits wake-active neurons to promote sleep. It has been specifically hypothesized that adenosine decreases wakefulness and promotes sleep recovery by directly inhibiting wake-active neurons of the basal forebrain (BF), particularly BF cholinergic neurons. We previously showed that adenosine directly inhibits BF cholinergic neurons. Here, we investigated 1) how adenosine modulates glutamatergic input to BF cholinergic neurons and 2) how adenosine uptake and adenosine metabolism are involved in regulating extracellular levels of adenosine. Our experiments were conducted using whole cell patch-clamp recordings in mouse brain slices. We found that in BF cholinergic neurons, adenosine reduced the amplitude of AMPA-mediated evoked glutamatergic excitatory postsynaptic currents (EPSCs) and decreased the frequency of spontaneous and miniature EPSCs through presynaptic A1 receptors. Thus we have demonstrated that in addition to directly inhibiting BF cholinergic neurons, adenosine depresses excitatory inputs to these neurons. It is therefore possible that both direct and indirect inhibition may synergistically contribute to the sleep-promoting effects of adenosine in the BF. We also found that blocking the influx of adenosine through the equilibrative nucleoside transporters or inhibiting adenosine kinase and adenosine deaminase increased endogenous adenosine inhibitory tone, suggesting a possible mechanism through which adenosine extracellular levels in the basal forebrain are regulated. PMID:22357797

  20. Comparing the context specificity of extinction and latent inhibition.

    PubMed

    Miller, Ralph R; Laborda, Mario A; Polack, Cody W; Miguez, Gonzalo

    2015-12-01

    Exposure to a cue alone either before (i.e., latent inhibition treatment) or after (i.e., extinction) the cue is paired with an unconditioned stimulus results in attenuated conditioned responding to the cue. Here we report two experiments in which potential parallels between the context specificity of the effects of extinction and latent inhibition treatments were directly compared in a lick suppression preparation with rats. The reversed ordering of conditioning and nonreinforcement in extinction and latent inhibition designs allowed us to examine the effect of training order on the context specificity of what is learned given phasic reinforcement and nonreinforcement of a target cue. Experiment 1 revealed that when conditioned-stimulus (CS) conditioning and CS nonreinforcement were administered in the same context, both extinction and latent inhibition treatments had reduced impacts on test performance, relative to excitatory conditioning when testing occurred outside the treatment context. Similarly, Experiment 2 showed that when conditioning was administered in one context and nonreinforcement was administered in a second context, the effects of both extinction and latent inhibition treatments were attenuated when testing occurred in a neutral context, relative to the context in which the CS was nonreinforced. The observed context specificity of extinction and latent inhibition treatments has been previously reported in both cases, but not in a single experiment under otherwise identical conditions. The results of the two experiments convergently suggest that memory of nonreinforcement becomes context dependent after a cue is both reinforced and nonreinforced, independent of the order of training. PMID:26100525

  1. Inhibition of Mycobacterium tuberculosis Methionine Aminopeptidases by Bengamide Derivatives

    SciTech Connect

    Lu, Jing-Ping; Yuan, Xiu-Hua; Yuan, Hai; Wang, Wen-Long; Wan, Baojie; Franzblau, Scott G.; Ye, Qi-Zhuang

    2012-05-29

    Methionine aminopeptidase (MetAP) carries out an essential function of protein N-terminal processing in many bacteria and is a promising target for the development of novel antitubercular agents. Natural bengamides potently inhibit the proliferation of mammalian cells by targeting MetAP enzymes, and the X-ray crystal structure of human type 2 MetAP in complex with a bengamide derivative reveals the key interactions at the active site. By preserving the interactions with the conserved residues inside the binding pocket while exploring the differences between bacterial and human MetAPs around the binding pocket, seven bengamide derivatives were synthesized and evaluated for inhibition of MtMetAP1a and MtMetAP1c in different metalloforms, inhibition of M. tuberculosis growth in replicating and non-replicating states, and inhibition of human K562 cell growth. Potent inhibition of MtMetAP1a and MtMetAP1c and modest growth inhibition of M. tuberculosis were observed for some of these derivatives. Crystal structures of MtMetAP1c in complex with two of the derivatives provided valuable structural information for improvement of these inhibitors for potency and selectivity.

  2. Iron chelators ICL670 and 311 inhibit HIV-1 transcription

    SciTech Connect

    Debebe, Zufan; Ammosova, Tatyana; Jerebtsova, Marina; Kurantsin-Mills, Joseph; Niu, Xiaomei; Charles, Sharroya; Richardson, Des R.; Ray, Patricio E.; Gordeuk, Victor R.; Nekhai, Sergei

    2007-10-25

    HIV-1 replication is induced by an excess of iron and iron chelation by desferrioxamine (DFO) inhibits viral replication by reducing proliferation of infected cells. Treatment of cells with DFO and 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311) inhibit expression of proteins that regulate cell-cycle progression, including cycle-dependent kinase 2 (CDK2). Our recent studies showed that CDK2 participates in HIV-1 transcription and viral replication suggesting that inhibition of CDK2 by iron chelators might also affect HIV-1 transcription. Here we evaluated the effect of a clinically approved orally effective iron chelator, 4-[3,5-bis-(hydroxyphenyl)-1,2,4-triazol-1-yl]-benzoic acid (ICL670) and 311 on HIV-1 transcription. Both ICL670 and 311 inhibited Tat-induced HIV-1 transcription in CEM-T cells, 293T and HeLa cells. Neither ICL670 nor 311 induced cytotoxicity at concentrations that inhibited HIV-1 transcription. The chelators decreased cellular activity of CDK2 and reduced HIV-1 Tat phosphorylation by CDK2. Neither ICL670A or 311 decreased CDK9 protein level but significantly reduced association of CDK9 with cyclin T1 and reduced phosphorylation of Ser-2 residues of RNA polymerase II C-terminal domain. In conclusion, our findings add to the evidence that iron chelators can inhibit HIV-1 transcription by deregulating CDK2 and CDK9. Further consideration should be given to the development of iron chelators for future anti-retroviral therapeutics.

  3. Inhibition of renal membrane binding and nephrotoxicity of aminoglycosides

    SciTech Connect

    Williams, P.D.; Hottendorf, G.H.; Bennett, D.B.

    1986-06-01

    The initial event in the renal tubular reabsorption of nephrotoxic aminoglycosides involves binding to brush border membranes. This primary event was measured in renal brush border membrane vesicles prepared from rat renal cortex utilizing (3H)gentamicin. In order to gain structure-activity information regarding this interaction the effect of substances having chemical similarities to aminoglycosides (sugars, polyamines and amino acids) on gentamicin binding to brush border membranes was determined. Polyamino acids were found to possess the greatest inhibitory potency. In addition to polymers of cationic amino acids (lysine, ornithine, arginine and histidine), polymers of neutral (asparagine) and acidic (aspartic and glutamic acid) amino acids also exhibited inhibition of the membrane binding of gentamicin. Inasmuch as inhibition of renal membrane binding has the potential to decrease aminoglycoside nephrotoxicity, several polyamino acids that inhibited membrane binding were tested in vivo for potential protective activity vs. gentamicin- and amikacin-induced nephrotoxicity. Polyasparagine90 and polyaspartic acid100 inhibited gentamicin and amikacin nephrotoxicity completely when coadministered to rats with the aminoglycosides. Polylysine20 provided complete and partial inhibition of gentamicin and amikacin nephrotoxicity, respectively. Whereas in vivo distribution studies revealed that cortical levels of (3H)amikacin were elevated slightly by the coadministration of polyaspartic acid, brush border and basolateral membranes contained significantly lower levels of the aminoglycoside (46 and 41% inhibition, respectively). These results question the role of charge per se in the binding of aminoglycosides to renal membranes and further confirm the importance of membrane binding in the pathogenesis of aminoglycoside nephrotoxicity.

  4. Inhibition of murine cardiomyocyte respiration by amine local anesthetics.

    PubMed

    Aburawi, Elhadi H; Souid, Abdul-Kader

    2014-12-01

    The hydrophobic amino acyl amide-linked local anesthetics (e.g., lidocaine and bupivacaine) impose potent cardiac toxicity and direct mitochondrial dysfunction. To investigate these adverse events, an in vitro system was employed to measure their effects on O2 consumption (cellular respiration) by murine myocardium. Specimens were collected from the ventricular myocardium and immediately immersed in ice-cold Krebs-Henseleit buffer saturated with 95 % O2:5 % CO2. O2 concentration was determined as a function of time from the phosphorescence decay rates of Pd(II)-meso-tetra-(4-sulfonatophenyl)-tetrabenzoporphyrin. Myocardial O2 consumption was linear with time (zero-order kinetics); its rate (k, in ?M O2 min(-1)), thus, was the negative of the slope of [O2] vs. time. Cyanide inhibited O2 consumption, confirming the oxidation occurred in the respiratory chain. Lidocaine and bupivacaine produced immediate and sustained inhibition of cellular respiration at plasma concentrations of the drugs (low micromolar range). Bupivacaine was twice as potent as lidocaine. The inhibition was dose-dependent, saturating at concentrations ?30 ?M. At saturating doses, lidocaine produced ~20 % inhibition and bupivacaine ~40 % inhibition. Cellular ATP was also decreased in the presence of 30 ?M lidocaine or bupivacaine. The studied amines inhibited myocardial cellular respiration. This effect is consistent with their known adverse events on mitochondrial function. The described approach allows accurate assessments and comparisons of the toxic effects of local anesthetics on heart tissue bioenergetics. PMID:24254523

  5. Inhibition of Photosystem 2 primary photochemistry by photogenerated protons.

    PubMed

    Finazzi, G; Bianchi, R; Vianelli, A; Ehrenheim, A M; Forti, G

    1995-01-01

    Photosystem 2 photochemical efficiency, measured as the rate of Qa reduction, was observed to be inhibited by preillumination with single turnover flashes, whilst Fo and Fm were not affected. Such inhibition was reversed by the uncoupler nigericin or by incubating the thylakoids in the dark for ca. 2 min after the preillumination. The presence of ATP in micromolar concentrations increased the time of dark recovery from the inhibition. The inhibition of fluorescence rise was not changed when 70% of the excitation energy available in the antenna was quenched by dinitrobenzene. Quantitative analysis of the observed fluorescence induction indicates that this phenomenon is due to the inhibition of the photochemical reaction itself. Uncouplers such NH4Cl were unable to reverse the inhibition and only a few flashes of saturating intensity (10 or less) were required for the onset of it. This suggests that protons localised in domains rather than a pH gradient between the thylakoid lumen bulk solution and the external one are involved in this regulation of PS 2 efficiency. PMID:24301632

  6. Inhibition of apple polyphenol oxidase activity by sodium chlorite.

    PubMed

    Lu, Shengmin; Luo, Yaguang; Feng, Hao

    2006-05-17

    Sodium chlorite (SC) was shown to have strong efficacy both as a sanitizer to reduce microbial growth on produce and as a browning inhibitor on fresh-cut apples in previous experiments. This study was undertaken to investigate the inhibitory effect of SC on polyphenol oxidase (PPO) and the associated mechanisms. The experiment showed that SC had a strong inhibition of apple PPO. The extent of inhibition was influenced by SC concentration and pH. Inhibition was most prominent at pH 4.5, at which approximately 30% of enzyme activity was lost in the presence of 10 mM SC, followed closely by that at pH 4.0 with a 26% reduction in PPO activity. The inhibition mode was determined using Dixon and Lineweaver-Burk plots, which established SC to be a mixed inhibitor of apple PPO for the oxidation of catechol. Preincubation of PPO with 8 mM SC for 8 min caused a maximum of 46% activity reduction compared to noninhibited control. However, preincubation of SC with catechol for 8 min resulted in no additional loss of PPO activity. These findings provide further evidence that the inhibition of PPO activity by SC is due to the inhibition of the enzyme itself rather than removal of the substrate. PMID:19127746

  7. Bryostatin-1 specifically inhibits in vitro IgE synthesis.

    PubMed

    Rabah, D; Grant, S; Ma, C; Conrad, D H

    2001-11-01

    Bryostatin-1, a macrocyclic lactone, is an antineoplastic agent that potently activates protein kinase C. Bryostatin-1 (Bryo) had an immunomodulatory effect on murine B cells in that it specifically inhibited IgE production. IgE levels were inhibited in a B cell dose-response curve, whereas IgM and IgG1 were induced by Bryo treatment. Taken together, ELISPOT and surface Ig staining data suggested that Bryo inhibition occurred at the level of class switching. RT-PCR and real time PCR data showed that this inhibition was achieved at an early step in switch recombination, namely, the appearance of Iepsilon germline transcripts. Although Bryo caused a delay in the proliferative response of IL-4/CD40 ligand trimer-stimulated B cells, CFSE studies revealed that the Bryo-mediated inhibition of class switching to IgE occurred independently of the number of division cycles. Notably, Bryo showed the same specific IgE inhibition in human B cells. This study provides evidence for a unique mechanism regulating IgE production possibly downstream of PKC by specifically modulating Iepsilon germline transcription. PMID:11673496

  8. The Inhibition of Lipase and Glucosidase Activities by Acacia Polyphenol

    PubMed Central

    Ikarashi, Nobutomo; Takeda, Rumi; Ito, Kiyomi; Ochiai, Wataru; Sugiyama, Kiyoshi

    2011-01-01

    Acacia polyphenol (AP) extracted from the bark of the black wattle tree (Acacia mearnsii) is rich in unique catechin-like flavan-3-ols, such as robinetinidol and fisetinidol. In an in vitro study, we measured the inhibitory activity of AP on lipase and glucosidase. In addition, we evaluated the effects of AP on absorption of orally administered olive oil, glucose, maltose, sucrose and starch solution in mice. We found that AP concentration-dependently inhibited the activity of lipase, maltase and sucrase with an IC50 of 0.95, 0.22 and 0.60?mg?ml?1, respectively. In ICR mice, olive oil was administered orally immediately after oral administration of AP solution, and plasma triglyceride concentration was measured. We found that AP significantly inhibited the rise in plasma triglyceride concentration after olive oil loading. AP also significantly inhibited the rise in plasma glucose concentration after maltose and sucrose loading, and this effect was more potent against maltose. AP also inhibited the rise in plasma glucose concentration after glucose loading and slightly inhibited it after starch loading. Our results suggest that AP inhibits lipase and glucosidase activities, which leads to a reduction in the intestinal absorption of lipids and carbohydrates. PMID:21660093

  9. Gbetagamma inhibits Galpha GTPase-activating proteins by inhibition of Galpha-GTP binding during stimulation by receptor.

    PubMed

    Tang, Wei; Tu, Yaping; Nayak, Surendra K; Woodson, Jimmy; Jehl, Markus; Ross, Elliott M

    2006-02-24

    Gbetagamma subunits modulate several distinct molecular events involved with G protein signaling. In addition to regulating several effector proteins, Gbetagamma subunits help anchor Galpha subunits to the plasma membrane, promote interaction of Galpha with receptors, stabilize the binding of GDP to Galpha to suppress spurious activation, and provide membrane contact points for G protein-coupled receptor kinases. Gbetagamma subunits have also been shown to inhibit the activities of GTPase-activating proteins (GAPs), both phospholipase C (PLC)-betas and RGS proteins, when assayed in solution under single turnover conditions. We show here that Gbetagamma subunits inhibit G protein GAP activity during receptor-stimulated, steady-state GTPase turnover. GDP/GTP exchange catalyzed by receptor requires Gbetagamma in amounts approximately equimolar to Galpha, but GAP inhibition was observed with superstoichiometric Gbetagamma. The potency of inhibition varied with the GAP and the Galpha subunit, but half-maximal inhibition of the GAP activity of PLC-beta1 was observed with 5-10 nM Gbetagamma, which is at or below the concentrations of Gbetagamma needed for regulation of physiologically relevant effector proteins. The kinetics of GAP inhibition of both receptor-stimulated GTPase activity and single turnover, solution-based GAP assays suggested a competitive mechanism in which Gbetagamma competes with GAPs for binding to the activated, GTP-bound Galpha subunit. An N-terminal truncation mutant of PLC-beta1 that cannot be directly regulated by Gbetagamma remained sensitive to inhibition of its GAP activity, suggesting that the Gbetagamma binding site relevant for GAP inhibition is on the Galpha subunit rather than on the GAP. Using fluorescence resonance energy transfer between cyan or yellow fluorescent protein-labeled G protein subunits and Alexa532-labeled RGS4, we found that Gbetagamma directly competes with RGS4 for high-affinity binding to Galpha(i)-GDP-AlF4. PMID:16407201

  10. A comparison of the effects of amphetamine, strychnine and caffeine on prepulse inhibition and latent inhibition.

    PubMed

    Bakshi, V.P.; Geyer, M.A.; Taaid, N.; Swerdlow, N.R.

    1995-12-01

    Sensorimotor gating deficits characterize several neuropsychiatric disorders, including schizophrenia. Prepulse inhibition (PPI) and latent inhibition (LI) are measures that are used to assess sensorimotor gating and have been found to be reduced in schizophrenia patients. In PPI, a weak stimulus presented immediately prior to a startling stimulus attenuates the startle response. In LI, pre-exposure to a stimulus retards the subsequent association of that stimulus with a consequence (e.g. footshock). In rats, indirect dopamine (DA) agonists such as amphetamine disrupt both PPI and LI. Amphetamine has also been reported to increase exploratory locomotion at doses that decrease PPI and LI. Such behavioral activation might complicate the interpretation of amphetamine-induced changes in measures of sensorimotor gating. The present study was conducted in order to compare the effects of three behaviorally activating drugs on PPI, LI and locomotor activity. Separate groups of rats were treated with either vehicle, the DA releaser amphetamine (1.5mg/kg), the glycine antagonist strychnine (0.75mg/kg), or the adenosine receptor antagonist caffeine (10mg/kg) and then tested in either startle chambers (for PPI) or an active avoidance chamber (for LI). Locomotion was measured by inter-trial crossing in the avoidance chamber. Amphetamine stimulated locomotion and disrupted both PPI and LI, but did not elevate startle amplitude. In contrast, caffeine increased locomotion, but had no effect on PPI or LI. Strychnine did not increase locomotion significantly, but did increase startle amplitude and disrupt PPI and LI. Hence, neither increased startle amplitude nor locomotor activation are necessary or sufficient conditions for disruption of sensorimotor gating as measured by PPI and LI. PMID:11224383

  11. Tanshinone IIA inhibits viral oncogene expression leading to apoptosis and inhibition of cervical cancer.

    PubMed

    Munagala, Radha; Aqil, Farrukh; Jeyabalan, Jeyaprakash; Gupta, Ramesh C

    2015-01-28

    Human papilloma virus (HPV) is the well-established etiological factor of cervical cancer. E6 and E7 oncoproteins expressed by HPV are known to inactivate tumor suppressor proteins p53 and pRb, respectively. Tanshinone IIA (Tan IIA) is a diterpenoid naphthoquinone found in the traditional Chinese medicine Danshen (Salvia sp.). Tan IIA has been shown to possess anti-tumor activity against several cancer types. In this study we show that Tan IIA potently inhibited proliferation of the human cervical cancer CaSki, SiHa, HeLa and C33a cells. Mechanistically in HPV positive CaSki cells, Tan IIA was found to (i) downregulate expression of HPV E6 and E7 genes and modulate associated proteins E6AP and E2F1, (ii) cause S phase cell cycle arrest, (iii) induce accumulation of p53 and alter expression of p53-dependent targets, (iv) modulate pRb and related proteins, and (v) cause p53-mediated apoptosis by moderating Bcl2, Bax, caspase-3, and PARP cleavage expressions. In vivo, Tan IIA resulted in over 66% reduction in tumor volume of cervical cancer xenograft in athymic nude mice. Tan IIA treated tumor tissues had lower expression of proliferation marker PCNA and changes in apoptosis targets were in agreement with in vitro studies, further confirming reduced proliferation and involvement of multiple targets behind anti-cancer effects. This is the first demonstration of Tan IIA to possess significant anti-viral activity by repressing HPV oncogenes leading to inhibition of cervical cancer. Together, our data suggest that Tan IIA can be exploited as a potent therapeutic agent for the prevention and treatment of cervical and other HPV-related cancers. PMID:25304375

  12. Inhibition of Akt inhibits growth of glioblastoma and glioblastoma stem-like cells.

    PubMed

    Gallia, Gary L; Tyler, Betty M; Hann, Christine L; Siu, I-Mei; Giranda, Vincent L; Vescovi, Angelo L; Brem, Henry; Riggins, Gregory J

    2009-02-01

    A commonly activated signaling cascade in many human malignancies, including glioblastoma multiforme, is the Akt pathway. This pathway can be activated via numerous upstream alterations including genomic amplification of epidermal growth factor receptor, PTEN deletion, or PIK3CA mutations. In this study, we screened phosphatidylinositol 3-kinase/Akt small-molecule inhibitors in an isogenic cell culture system with an activated Akt pathway secondary to a PIK3CA mutation. One small molecule, A-443654, showed the greatest selective inhibition of cells with the mutant phenotype. Based on these findings, this inhibitor was screened in vitro against a panel of glioblastoma multiforme cell lines. All cell lines tested were sensitive to A-443654 with a mean IC(50) of approximately 150 nmol/L. An analogue of A-443654, methylated at a region that blocks Akt binding, was on average 36-fold less active. Caspase assays and dual flow cytometric analysis showed an apoptotic mechanism of cell death. A-443654 was further tested in a rat intracranial model of glioblastoma multiforme. Animals treated intracranially with polymers containing A-443654 had significantly extended survival compared with control animals; animals survived 79% and 43% longer than controls when A-443654-containing polymers were implanted simultaneously or in a delayed fashion, respectively. This small molecule also inhibited glioblastoma multiforme stem-like cells with similar efficacy compared with traditionally cultured glioblastoma multiforme cell lines. These results suggest that local delivery of an Akt small-molecule inhibitor is effective against experimental intracranial glioma, with no observed resistance to glioblastoma multiforme cells grown in stem cell conditions. PMID:19208828

  13. DMSO inhibits human platelet activation through cyclooxygenase-1 inhibition. A novel agent for drug eluting stents?

    SciTech Connect

    Asmis, Lars; Tanner, Felix C.; Center for Integrative Human Physiology, University of Zuerich, Zuerich; Cardiology, Cardiovascular Center, University Hospital Zuerich, Zuerich ; Sudano, Isabella; Luescher, Thomas F.; Center for Integrative Human Physiology, University of Zuerich, Zuerich; Cardiology, Cardiovascular Center, University Hospital Zuerich, Zuerich ; Camici, Giovanni G.

    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 analysis 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.

  14. Bcl-2 family inhibition sensitizes human prostate cancer cells to docetaxel and promotes unexpected apoptosis under caspase-9 inhibition.

    PubMed

    Tamaki, Hiroki; Harashima, Nanae; Hiraki, Miho; Arichi, Naoko; Nishimura, Nobuhiro; Shiina, Hiroaki; Naora, Kohji; Harada, Mamoru

    2014-11-30

    Docetaxel (DTX) is a useful chemotherapeutic drug for the treatment of hormone-refractory prostate cancer. However, emergence of DTX resistance has been a therapeutic hurdle. In this study, we investigated the effect of combining DTX with Bcl-2 family inhibitors using human prostate cancer cell lines (PC3, LNCaP, and DU145 cells). PC3 cells were less sensitive to DTX than were the other two cell lines. In contrast to ABT-199, which inhibits Bcl-2 and Bcl-w, both ABT-263 and ABT-737, which inhibit Bcl-2, Bcl-xL, and Bcl-w, significantly augmented the antitumor effect of DTX on PC3 cells. ABT-263 also enhanced the antitumor effect of DTX on a DTX-resistant PC3 variant cell line. The antitumor effect of ABT-263 was due mainly to its inhibitory effect on Bcl-xL. In a xenograft mouse model, DTX and ABT-737 combination therapy significantly inhibited PC3 tumor growth. Interestingly, although ABT-263 activated caspase-9 in PC3 cells, inhibition of caspase-9 unexpectedly promoted ABT-263-induced apoptosis in a caspase-8-dependent manner. This augmented apoptosis was also observed in LNCaP cells. These findings indicate that Bcl-xL inhibition can sensitize DTX-resistant prostate cancer cells to DTX, and they reveal a unique apoptotic pathway in which antagonism of Bcl-2 family members in caspase-9-inhibited prostate cancer cells triggers caspase-8-dependent apoptosis. PMID:25333266

  15. Celastrol inhibits TGF-?1-induced epithelial–mesenchymal transition by inhibiting Snail and regulating E-cadherin expression

    SciTech Connect

    Kang, Hyereen; Lee, Minjae; Jang, Sung-Wuk; Department of Biochemistry and Molecular Biology, University of Ulsan College of Medicine, Seoul 138-736

    2013-08-09

    Highlights: •We investigated the effects of celastrol on TGF-?1-induced EMT in epithelial cells. •Celastrol regulates TGF-?1-induced morphological changes and E-cadherin expression. •Celastrol inhibits TGF-?1-induced Snail expression. •Celastrol strongly suppresses TGF-?1-induced invasion in MDCK and A549 cells. -- Abstract: The epithelial–mesenchymal transition (EMT) is a pivotal event in the invasive and metastatic potentials of cancer progression. Celastrol inhibits the proliferation of a variety of tumor cells including leukemia, glioma, prostate, and breast cancer; however, the possible role of celastrol in the EMT is unclear. We investigated the effect of celastrol on the EMT. Transforming growth factor-beta 1 (TGF-?1) induced EMT-like morphologic changes and upregulation of Snail expression. The downregulation of E-cadherin expression and upregulation of Snail in Madin–Darby Canine Kidney (MDCK) and A549 cell lines show that TGF-?1-mediated the EMT in epithelial cells; however, celastrol markedly inhibited TGF-?1-induced morphologic changes, Snail upregulation, and E-cadherin expression. Migration and invasion assays revealed that celastrol completely inhibited TGF-?1-mediated cellular migration in both cell lines. These findings indicate that celastrol downregulates Snail expression, thereby inhibiting TGF-?1-induced EMT in MDCK and A549 cells. Thus, our findings provide new evidence that celastrol suppresses lung cancer invasion and migration by inhibiting TGF-?1-induced EMT.

  16. MMI-0100 inhibits cardiac fibrosis in myocardial infarction by direct actions on cardiomyocytes and fibroblasts via MK2 inhibition

    PubMed Central

    Xu, Lei; Yates, Cecelia C.; Lockyer, Pamela; Xie, Liang; Bevilacqua, Ariana; He, Jun; Lander, Cynthia; Patterson, Cam; Willis, Monte

    2014-01-01

    The cell-permeant peptide inhibitor of MAPKAP kinase 2 (MK2), MMI-0100, inhibits MK2 and downstream fibrosis and inflammation. Recent studies have demonstrated that MMI-0100 reduces intimal hyperplasia in a mouse vein graft model, pulmonary fibrosis in a murine bleomycin-induced model and development of adhesions in conjunction with abdominal surgery. MK2 is critical to the pathogenesis of ischemic heart injury as MK2 ?/? mice are resistant to ischemic remodeling. Therefore, we tested the hypothesis that inhibiting MK2 with MMI-0100 would protect the heart after acute myocardial infarction (AMI) in vivo. AMI was induced by placing a permanent LAD coronary ligation. When MMI-0100 peptide was given 30 minutes after permanent LAD coronary artery ligation, the resulting fibrosis was reduced/prevented ~50% at a 2 week time point, with a corresponding improvement in cardiac function and decrease in left ventricular dilation. In cultured cardiomyocytes and fibroblasts, MMI-0100 inhibited MK2 to reduce cardiomyocyte caspase 3/7 activity, while enhancing primary cardiac fibroblast caspase 3/7 activity, which may explain MMI-0100’s salvage of cardiac function and anti-fibrotic effects in vivo. These findings suggest that therapeutic inhibition of MK2 after acute MI, using rationally-designed cell-permeant peptides, inhibits cardiac fibrosis and maintains cardiac function by mechanisms that involve inhibiting cardiomyocyte apoptosis, while enhancing primary cardiac fibroblast cell death. PMID:25257914

  17. Hyperoxia Inhibits T Cell Activation in Mice

    NASA Astrophysics Data System (ADS)

    Hughes-Fulford, M.; Meissler, J.; Aguayo, E. T.; Globus, R.; Aguado, J.; Candelario, T.

    2013-02-01

    Background: The immune response is blunted in mice and humans in spaceflight. The effects of hyperoxia in mice alter expression of some of the same immune response genes. If these two conditions are additive, there could be an increased risk of infection in long duration missions. Immunosuppression is seen in healthy astronauts who have flown in space; however little is known about the mechanisms that cause the reduced immunity in spaceflight. Here we examine the role of oxidative stress on mice exposed to periods of high O2 levels mimicking pre-breathing protocols and extravehicular activity (EVA). To prevent decompression sickness, astronauts are exposed to elevated oxygen (hyperoxia) before and during EVA activities. Spaceflight missions may entail up to 24 hours of EVA per crewmember per week to perform construction and maintenance tasks. The effectiveness and success of these missions depends on designing EVA systems and protocols that maximize human performance and efficiency while minimizing health and safety risks for crewmembers. To our knowledge, no studies have been conducted on the immune system under 100% oxygen exposures to determine the potential for immune compromise due to prolonged and repeated EVAs. Methods: Animals were exposed to hyperoxic or control conditions for 8 hours per day over a period of 3 days, initiated 4 hours into the dark cycle (12h dark/12h light), using animal environmental control cabinets and oxygen controller (Biospherix, Lacona, NY). Experimental mice were exposed to 98-100% oxygen as a model for pre-breathing and EVA conditions, while control mice were maintained in chambers supplied with compressed air. These are ground control studies where we use real-time RTPCR (qRTPCR) to measure gene expression of the early immune gene expression during bead activation of splenocytes of normoxic and hyperoxic mice. All procedures were reviewed and approved by the IACUC at Ames Research Center. After the last 8h of hyperoxic exposure, spleens were removed and the splenocytes were isolated and kept as individual biological samples. We have also examined transcription factors (JASPAR) and pathways of the immune system to help us understand the mechanism of regulation. Results: Our recent mouse immunology experiment aboard STS-131 suggests that the early T cell immune response was inhibited in animals that have been exposed to spaceflight, even 24 hours after return to earth. Moreover, recent experiments in hyperoxic mice show that many of the same genes involved in early T cell activation were altered. Specifically, expression of IL-2R?, Cxcl2, TNF?, FGF2, LTA and BCL2 genes are dysregulated in mice exposed to hyperoxia. Conclusions: If these hyperoxia-induced changes of gene expression in early T cell activation are additive to the changes seen in the microgravity of spaceflight, there could be an increased infection risk to EVA astronauts, which should be addressed prior to conducting a Mars or other long-term mission.

  18. Global Precipitation Measurement (GPM) Safety Inhibit Timeline Tool

    NASA Technical Reports Server (NTRS)

    Dion, Shirley

    2012-01-01

    The Global Precipitation Measurement (GPM) Observatory is a joint mission under the partnership by National Aeronautics and Space Administration (NASA) and the Japan Aerospace Exploration Agency (JAXA), Japan. The NASA Goddard Space Flight Center (GSFC) has the lead management responsibility for NASA on GPM. The GPM program will measure precipitation on a global basis with sufficient quality, Earth coverage, and sampling to improve prediction of the Earth's climate, weather, and specific components of the global water cycle. As part of the development process, NASA built the spacecraft (built in-house at GSFC) and provided one instrument (GPM Microwave Imager (GMI) developed by Ball Aerospace) JAXA provided the launch vehicle (H2-A by MHI) and provided one instrument (Dual-Frequency Precipitation Radar (DPR) developed by NTSpace). Each instrument developer provided a safety assessment which was incorporated into the NASA GPM Safety Hazard Assessment. Inhibit design was reviewed for hazardous subsystems which included the High Gain Antenna System (HGAS) deployment, solar array deployment, transmitter turn on, propulsion system release, GMI deployment, and DPR radar turn on. The safety inhibits for these listed hazards are controlled by software. GPM developed a "pathfinder" approach for reviewing software that controls the electrical inhibits. This is one of the first GSFC in-house programs that extensively used software controls. The GPM safety team developed a methodology to document software safety as part of the standard hazard report. As part of this process a new tool "safety inhibit time line" was created for management of inhibits and their controls during spacecraft buildup and testing during 1& Tat GSFC and at the Range in Japan. In addition to understanding inhibits and controls during 1& T the tool allows the safety analyst to better communicate with others the changes in inhibit states with each phase of hardware and software testing. The tool was very useful for communicating compliance with safety requirements especially when working with a foreign partner.

  19. DASATINIB INHIBITS THE GROWTH OF MOLECULARLY HETEROGENEOUS MYELOID LEUKEMIAS

    PubMed Central

    Guerrouahen, Bella S.; Futami, Muneyoshi; Vaklavas, Christos; Kanerva, Jukka; Whichard, Zakary L.; Nwawka, Kenechi; Blanchard, Elisabeth G.; Lee, Francis Y.; Robinson, Lisa J.; Arceci, Robert; Kornblau, Steven M.; Wieder, Eric; Cayre, Yvon E.; Corey, Seth J.

    2010-01-01

    Purpose Dasatinib is a dual Src/Abl inhibitor, recently approved for Bcr-Abl+ leukemias with resistance or intolerance to prior therapy. Because Src kinases contribute to multiple blood cell functions by triggering a variety of signaling pathways, we hypothesized that their molecular targeting might lead to growth inhibition in acute myeloid leukemia (AML). Experimental Design We studied growth factor-dependent and independent leukemic cell lines, including three cell lines expressing mutants of receptor tyrosine kinases (Flt3 or c-Kit) as well as primary AML blasts for responsiveness to dasatinib. Results Dasatinib resulted in the inhibition of Src family kinases in all cell lines and blast cells at ~10?9 M. It also inhibited mutant Flt3 or Kit tyrosine phosphorylation at ~10?6 M. Mo7e cells expressing the activating mutation (codon 816) of c-Kit were most sensitive to growth inhibition with a GI50 5×10?9 M. Primary AML blast cells exhibited growth inhibition < 10?6 M. Cell lines which showed growth inhibition at ~10?6 M demonstrated a G1 cell cycle arrest and correlated with accumulation of p21 and p27 protein. Addition of rapamycin or cytotoxic agents enhanced the growth inhibition. Dasatinib also caused the apoptosis of Mo7e cells expressing oncogenic Kit. Conclusions While all of the precise targets for dasatinib are not known, this multi-kinase inhibitor causes either growth arrest or apoptosis in molecularly heterogeneous AML. Addition of cytotoxic or targeted agents can enhance its effects. PMID:20145167

  20. The endogenous cannabinoid anandamide inhibits human breast cancer cell proliferation.

    PubMed

    De Petrocellis, L; Melck, D; Palmisano, A; Bisogno, T; Laezza, C; Bifulco, M; Di Marzo, V

    1998-07-01

    Anandamide was the first brain metabolite shown to act as a ligand of "central" CB1 cannabinoid receptors. Here we report that the endogenous cannabinoid potently and selectively inhibits the proliferation of human breast cancer cells in vitro. Anandamide dose-dependently inhibited the proliferation of MCF-7 and EFM-19 cells with IC50 values between 0.5 and 1.5 microM and 83-92% maximal inhibition at 5-10 microM. The proliferation of several other nonmammary tumoral cell lines was not affected by 10 microM anandamide. The anti-proliferative effect of anandamide was not due to toxicity or to apoptosis of cells but was accompanied by a reduction of cells in the S phase of the cell cycle. A stable analogue of anandamide (R)-methanandamide, another endogenous cannabinoid, 2-arachidonoylglycerol, and the synthetic cannabinoid HU-210 also inhibited EFM-19 cell proliferation, whereas arachidonic acid was much less effective. These cannabimimetic substances displaced the binding of the selective cannabinoid agonist [3H]CP 55, 940 to EFM-19 membranes with an order of potency identical to that observed for the inhibition of EFM-19 cell proliferation. Moreover, anandamide cytostatic effect was inhibited by the selective CB1 receptor antagonist SR 141716A. Cell proliferation was arrested by a prolactin mAb and enhanced by exogenous human prolactin, whose mitogenic action was reverted by very low (0.1-0.5 microM) doses of anandamide. Anandamide suppressed the levels of the long form of the prolactin receptor in both EFM-19 and MCF-7 cells, as well as a typical prolactin-induced response, i.e., the expression of the breast cancer cell susceptibility gene brca1. These data suggest that anandamide blocks human breast cancer cell proliferation through CB1-like receptor-mediated inhibition of endogenous prolactin action at the level of prolactin receptor. PMID:9653194

  1. gp-91 mediates histone deacetylase inhibition-induced cardioprotection

    PubMed Central

    Zhao, Ting C; Zhang, Ling X; Cheng, Guangmao; Liu, Jun T

    2010-01-01

    We have recently shown that the inhibition of histone deacetylases (HDAC) protects the heart against ischemia and reperfusion (I/R) injury. The mechanism by which HDAC inhibition induces cardioprotection remains unknown. We sought to investigate whether the genetic disruption of gp-91, a subunit of NADPH-oxidase, would mitigate cardioprotection of HDAC inhibition. Wild-type and gp-91?/? mice were treated with a potent inhibitor of HDACs, trichostatin A (TSA, 0.1mg/kg, i.p.). Twenty-four hours later, the perfused hearts were subjected to 30 min of ischemia and 30 min of reperfusion. HDAC inhibition in wild-type mice produced marked improvements in ventricular functional recovery and the reduction of infarct size. TSA-induced cardioprotection was eliminated with genetic deletion of gp91. Notably, Western blot and immunostaining displayed a significant increase in gp-91 in myocardium following HDAC inhibition, which resulted in a mildly subsequent increase in the production of reactive oxygen species (ROS). The pretreatment of H9c2 cardiomyoblasts with TSA (50 nmol/L) decreased cell necrosis and increased viability in response to simulated ischemia (SI), which was abrogated by the transfection of cells with gp-91 siRNA, but not by scrambled siRNA. Furthermore, treatment of PLB-985 gp91+/+cells with TSA increased the resistance to SI, which also diminished with genetic disruption of gp91 in gp91phox-deficient PLB-985 cells. TSA treatment inhibited the increased active caspase-3 in H9c2 cardiomyoblasts and PLB-985 gp91+/+cells exposed to SI, which were prevented by knockdown of gp-91 by siRNA. These results suggest that a cascade consisting of gp-91 and HDAC inhibition plays an essential role in orchestrating the cardioprotective effect. PMID:20433879

  2. Benzonatate inhibition of voltage-gated sodium currents.

    PubMed

    Evans, M Steven; Maglinger, G Benton; Fletcher, Anita M; Johnson, Stephen R

    2016-02-01

    Benzonatate was FDA-approved in 1958 as an antitussive. Its mechanism of action is thought to be anesthesia of vagal sensory nerve fibers that mediate cough. Vagal sensory neurons highly express the Nav1.7 subtype of voltage-gated sodium channels, and inhibition of this channel inhibits the cough reflex. Local anesthetics inhibit voltage-gated sodium channels, but there are no reports of whether benzonatate affects these channels. Our hypothesis is that benzonatate inhibits Nav1.7 voltage-gated sodium channels. We used whole cell voltage clamp recording to test the effects of benzonatate on voltage-gated sodium (Na(+)) currents in two murine cell lines, catecholamine A differentiated (CAD) cells, which express primarily Nav1.7, and N1E-115, which express primarily Nav1.3. We found that, like local anesthetics, benzonatate strongly and reversibly inhibits voltage-gated Na(+) channels. Benzonatate causes both tonic and phasic inhibition. It has greater effects on channel inactivation than on activation, and its potency is much greater at depolarized potentials, indicating inactivated-state-specific effects. Na(+) currents in CAD cells and N1E-115 cells are similarly affected, indicating that benzonatate is not Na(+) channel subtype-specific. Benzonatate is a mixture of polyethoxy esters of 4-(butylamino) benzoic acid having varying degrees of hydrophobicity. We found that Na(+) currents are inhibited most potently by a benzonatate fraction containing the 9-ethoxy component. Detectable effects of benzonatate occur at concentrations as low as 0.3 ?M, which has been reported in humans. We conclude that benzonatate has local anesthetic-like effects on voltage-gated sodium channels, including Nav1.7, which is a possible mechanism for cough suppression by the drug. PMID:26386152

  3. Toll-like receptor 2 agonists inhibit human fibrocyte differentiation

    PubMed Central

    2010-01-01

    Background In healing wounds, some monocytes enter the wound and differentiate into fibroblast-like cells called fibrocytes. Since Toll-like receptors (TLRs) are present on monocytes, and pathogens that can infect a wound have and/or release TLR agonists, we examined whether TLR agonists affect fibrocyte differentiation. Results When human peripheral blood mononuclear cells (PBMCs) were cultured with TLR3, TLR4, TLR5, TLR7, TLR8 or TLR9 agonists, there was no significant effect on fibrocyte differentiation, even though enhanced extracellular tumor necrosis factor (TNF)-? accumulation and/or increased cell surface CD86 or major histocompatibility complex (MHC) class II levels were observed. However, all TLR2 agonists tested inhibited fibrocyte differentiation without any significant effect on cell survival. Adding TLR2 agonists to purified monocytes had no effect on fibrocyte differentiation. However, some TLR2 agonists caused PBMCs to secrete a factor that inhibits the differentiation of purified monocytes into fibrocytes. This factor is not interferon (IFN)-?, IFN-?, interleukin (IL)-12, aggregated immunoglobulin G (IgG) or serum amyloid P (SAP), factors known to inhibit fibrocyte differentiation. TLR2 agonist-treated PBMCs secrete low levels of IL-6, TNF-?, IFN-?, granulocyte colony-stimulating factor and tumor growth factor ?1, but combinations of these factors had no effect on fibrocyte differentiation from purified monocytes. Conclusions Our results indicate that TLR2 agonists indirectly inhibit fibrocyte differentiation and that, for some TLR2 agonists, this inhibition involves other cell types in the PBMC population secreting an unknown factor that inhibits fibrocyte differentiation. Together, these data suggest that the presence of some bacterial signals can inhibit fibrocyte differentiation and may thus slow wound closure. PMID:21106092

  4. Inhibition shapes acoustic responsiveness in spherical bushy cells.

    PubMed

    Keine, Christian; Rübsamen, Rudolf

    2015-06-01

    Signal processing in the auditory brainstem is based on an interaction of neuronal excitation and inhibition. To date, we have incomplete knowledge of how the dynamic interplay of both contributes to the processing power and temporal characteristics of signal coding. The spherical bushy cells (SBCs) of the anteroventral cochlear nucleus (AVCN) receive their primary excitatory input through auditory nerve fibers via large, axosomatic synaptic terminals called the endbulbs of Held and by additional, acoustically driven inhibitory inputs. SBCs provide the input to downstream nuclei of the brainstem sound source localization circuitry, such as the medial and lateral superior olive, which rely on temporal precise inputs. In this study, we used juxtacellular recordings in anesthetized Mongolian gerbils to assess the effect of acoustically evoked inhibition on the SBCs input-output function and on temporal precision of SBC spiking. Acoustically evoked inhibition proved to be strong enough to suppress action potentials (APs) of SBCs in a stimulus-dependent manner. Inhibition shows slow onset and offset dynamics and increasing strength at higher sound intensities. In addition, inhibition decreases the rising slope of the EPSP and prolongs the EPSP-to-AP transition time. Both effects can be mimicked by iontophoretic application of glycine. Inhibition also improves phase locking of SBC APs to low-frequency tones by acting as a gain control to suppress poorly timed EPSPs from generating postsynaptic APs to maintain precise SBC spiking across sound intensities. The present data suggest that inhibition substantially contributes to the processing power of second-order neurons in the ascending auditory system. PMID:26041924

  5. Response inhibition and its relation to multidimensional impulsivity.

    PubMed

    Wilbertz, Tilmann; Deserno, Lorenz; Horstmann, Annette; Neumann, Jane; Villringer, Arno; Heinze, Hans-Jochen; Boehler, Carsten N; Schlagenhauf, Florian

    2014-12-01

    Impulsivity is a multidimensional construct that has been suggested as a vulnerability factor for several psychiatric disorders, especially addiction disorders. Poor response inhibition may constitute one facet of impulsivity. Trait impulsivity can be assessed by self-report questionnaires such as the widely used Barratt Impulsiveness Scale (BIS-11). However, regarding the multidimensionality of impulsivity different concepts have been proposed, in particular the UPPS self-report questionnaire ('Urgency', 'Lack of Premeditation', 'Lack of Perseverance', 'Sensation Seeking') that is based on a factor analytic approach. The question as to which aspects of trait impulsivity map on individual differences of the behavioral and neural correlates of response inhibition so far remains unclear. In the present study, we investigated 52 healthy individuals that scored either very high or low on the BIS-11 and underwent a reward-modulated Stop-signal task during fMRI. Neither behavioral nor neural differences were observed with respect to high- and low-BIS groups. In contrast, UPPS subdomain Urgency best explained inter-individual variability in SSRT scores and was further negatively correlated to right IFG/aI activation in 'Stop>Go' trials - a key region for response inhibition. Successful response inhibition in rewarded compared to nonrewarded stop trials yielded ventral striatal (VS) activation which might represent a feedback signal. Interestingly, only participants with low Urgency scores were able to use this VS feedback signal for better response inhibition. Our findings indicate that the relationship of impulsivity and response inhibition has to be treated carefully. We propose Urgency as an important subdomain that might be linked to response inhibition as well as to the use of reward-based neural signals. Based on the present results, further studies examining the influence of impulsivity on psychiatric disorders should take into account Urgency as an important modulator of behavioral adaptation. PMID:25241087

  6. DIFFERENTIAL PROFILES OF CHOLINESTERASE INHIBITION AND NEUROBEHAVIORAL EFFECTS IN RATS EXPOSED TO FENAMIPHOS AND PROFENOPHOS.

    EPA Science Inventory

    The relationship between cholinesterase (ChE) inhibition and neurobehavioral changes was examined using two ChE-inhibiting organophosphorus pesticides, fenamiphos and profenophos. Both pesticides inhibit blood ChE, yet brain ChE is relatively spared (little to no inhibition up t...

  7. Reactive and Reciprocal Inhibition Therapies in the Group Treatment of Test Anxiety.

    ERIC Educational Resources Information Center

    Kearney, Maureen

    This experiment compares the effects of group reactive inhibition therapy and group reciprocal inhibition therapy with no treatment on the anxiety level of test-anxious college students. Twenty undergraduate students volunteered for the study and were assigned to either the reactive inhibition group, the reciprocal inhibition group, or the…

  8. Inhibited and Aggressive Preschool Children at 23 Years of Age: Personality and Social Transitions into Adulthood

    ERIC Educational Resources Information Center

    Asendorpf, Jens B.; Denissen, Jaap J. A.; van Aken, Marcel A. G.

    2008-01-01

    In a 19-year longitudinal study, the 15% most inhibited and the 15% most aggressive children at ages 4-6 years were followed up until age 23 years and were compared with controls who were below average in preschool inhibition or aggressiveness. As adults, inhibited boys and girls were judged as inhibited by their parents and showed a delay in…

  9. Small molecule proprotein convertase inhibitors for inhibition of embryo implantation.

    PubMed

    Ho, Huiting; Singh, Harmeet; Heng, Sophea; Nero, Tracy L; Paule, Sarah; Parker, Michael W; Johnson, Alan T; Jiao, Guan-Sheng; Nie, Guiying

    2013-01-01

    Uterine proprotein convertase (PC) 6 plays a critical role in embryo implantation and is pivotal for pregnancy establishment. Inhibition of PC6 may provide a novel approach for the development of non-hormonal and female-controlled contraceptives. We investigated a class of five synthetic non-peptidic small molecule compounds that were previously reported as potent inhibitors of furin, another PC member. We examined (i) the potency of these compounds in inhibiting PC6 activity in vitro; (ii) their binding modes in the PC6 active site in silico; (iii) their efficacy in inhibiting PC6-dependent cellular processes essential for embryo implantation using human cell-based models. All five compounds showed potent inhibition of PC6 activity in vitro, and in silico docking demonstrated that these inhibitors could adopt a similar binding mode in the PC6 active site. However, when these compounds were tested for their inhibition of decidualization of primary human endometrial stromal cells, a PC6-dependent cellular process critical for embryo implantation, only one (compound 1o) showed potent inhibition. The lack of activity in the cell-based assay may reflect the inability of the compounds to penetrate the cell membrane. Because compound's lipophilicity is linked to cell penetration, a measurement of lipophilicity (logP) was calculated for each compound. Compound 1o is unique as it appears the most lipophilic among the five compounds. Compound 1o also inhibited another crucial PC6-dependent process, the attachment of human trophoblast spheroids to endometrial epithelial cells (a model for human embryo attachment). We thus identified compound 1o as a potent small molecule PC6 inhibitor with pharmaceutical potential to inhibit embryo implantation. Our findings also highlight that human cell-based functional models are vital to complement the biochemical and in silico analyses in the selection of promising drug candidates. Further investigations for compound 1o are warranted in animal models to test its utility as an implantation-inhibiting contraceptive drug. PMID:24324690

  10. Transcriptome dynamics of the microRNA inhibition response.

    PubMed

    Wen, Jiayu; Leucci, Elenora; Vendramin, Roberto; Kauppinen, Sakari; Lund, Anders H; Krogh, Anders; Parker, Brian J

    2015-07-27

    We report a high-resolution time series study of transcriptome dynamics following antimiR-mediated inhibition of miR-9 in a Hodgkin lymphoma cell-line-the first such dynamic study of the microRNA inhibition response-revealing both general and specific aspects of the physiological response. We show miR-9 inhibition inducing a multiphasic transcriptome response, with a direct target perturbation before 4 h, earlier than previously reported, amplified by a downstream peak at ?32 h consistent with an indirect response due to secondary coherent regulation. Predictive modelling indicates a major role for miR-9 in post-transcriptional control of RNA processing and RNA binding protein regulation. Cluster analysis identifies multiple co-regulated gene regulatory modules. Functionally, we observe a shift over time from mRNA processing at early time points to translation at later time points. We validate the key observations with independent time series qPCR and we experimentally validate key predicted miR-9 targets. Methodologically, we developed sensitive functional data analytic predictive methods to analyse the weak response inherent in microRNA inhibition experiments. The methods of this study will be applicable to similar high-resolution time series transcriptome analyses and provides the context for more accurate experimental design and interpretation of future microRNA inhibition studies. PMID:26089393

  11. Transcriptome dynamics of the microRNA inhibition response

    PubMed Central

    Wen, Jiayu; Leucci, Elenora; Vendramin, Roberto; Kauppinen, Sakari; Lund, Anders H.; Krogh, Anders; Parker, Brian J.

    2015-01-01

    We report a high-resolution time series study of transcriptome dynamics following antimiR-mediated inhibition of miR-9 in a Hodgkin lymphoma cell-line—the first such dynamic study of the microRNA inhibition response—revealing both general and specific aspects of the physiological response. We show miR-9 inhibition inducing a multiphasic transcriptome response, with a direct target perturbation before 4 h, earlier than previously reported, amplified by a downstream peak at ?32 h consistent with an indirect response due to secondary coherent regulation. Predictive modelling indicates a major role for miR-9 in post-transcriptional control of RNA processing and RNA binding protein regulation. Cluster analysis identifies multiple co-regulated gene regulatory modules. Functionally, we observe a shift over time from mRNA processing at early time points to translation at later time points. We validate the key observations with independent time series qPCR and we experimentally validate key predicted miR-9 targets. Methodologically, we developed sensitive functional data analytic predictive methods to analyse the weak response inherent in microRNA inhibition experiments. The methods of this study will be applicable to similar high-resolution time series transcriptome analyses and provides the context for more accurate experimental design and interpretation of future microRNA inhibition studies. PMID:26089393

  12. Inhibition of a thermophilic deoxyribonucleic acid polymerase by fullerene derivatives.

    PubMed

    Meng, Xianmei; Li, Bo; Chen, Zhe; Yao, Lu; Zhao, Dongxu; Yang, Xinlin; He, Min; Yu, Qun

    2007-06-01

    Enzyme inhibition by fullerene derivatives has attracted much attention. In this communication, effects of two water-solube fullerene derivatives, fullerol and trimalonic acid C60 (TMA C60) on polymerase chain reaction (PCR) were investigated by using PCR of beta-actin cDNA derived from HeLa cells as an experimental model. Both fullerol and TMA C60 were found to inhibit PCR in a dose-dependent manner. PCR was ultimately inhibited while the concentrations of each compound were not less than 0.01 mM. In contrast, mannitol exerted no effects on PCR while its concentration increased up to 2 mM. Compensation experiments with Thermus aquaticus (Taq) DNA polymerase revealed that both fullerol and TMA C60 inhibited the enzymatic activity of Taq DNA polymerase, and the inhibitory potency of TMA C60 was slightly greater than that of fullerol. Our data provides some novel aspects on the enzyme inhibiting activities of fullerene derivatives. PMID:17674810

  13. In vitro reversibility of cadmium-induced inhibition of phagocytosis

    SciTech Connect

    Levy, L.; Vredevoe, D.L.; Cook, G.

    1986-12-01

    Cadmium chloride, administered chronically in the drinking water of CBA/H mice, produced a delayed clearance of particles and soluble material bearing Fc fragments. The inhibition was reversed upon removal of the cadmium from the water, even though a tissue load of cadmium persisted. An in vitro system was developed to analyze the mechanism of the inhibition. Binding and ingestion of sheep red blood cells (E) treated with IgG (for measurement of Fc receptor activity) or IgM and complement (C) (for measurement of complement receptor activity) were studied in resident and elicited murine peritoneal macrophages in vitro. Elicited macrophages provided the most definitive test system. With this system, there was significant inhibition of ingestion of E-IgG and E-IgMC. Binding of both types of erythrocytes was not inhibited, except at the highest concentration (10/sup -4/ M) of CdCl/sub 2/ at which binding of only E-IgMC was affected. These effects were reversible upon removal of cadmium. Migration of Fc and C receptors on the macrophage surface was not significantly affected by cadmium. In general, cadmium did not alter the expression or the binding of Fc or C receptors on macrophages. The mechanism for delayed clearance appears to be due to inhibited internalization of the particles. This is consistent with the interpretation that cadmium is a membrane active agent.

  14. Genistein suppresses FLT4 and inhibits human colorectal cancer metastasis

    PubMed Central

    Wang, Rui; Wang, Jiayin; Zhang, Song; Cai, Xiqiang; Wu, Kaichun; Bergan, Raymond C.; Xu, Li; Fan, Daiming

    2015-01-01

    Dietary consumption of genistein, found in soy, has been associated with a potentially protective role in colorectal cancer (CRC) development and progression. Herein we demonstrate that genistein will inhibit human CRC cell invasion and migration, that it does so at non-cytotoxic concentrations and we demonstrate this in multiple human CRC cell lines. After orthotopic implantation of human CRC tumors into mice, oral genistein did not inhibit tumor growth, but did inhibit distant metastasis formation, and was non-toxic to mice. Using a qPCR array, we screened for genistein-induced changes in gene expression, followed by Western blot confirmation, demonstrating that genistein downregulated matrix metalloproteinase 2 and Fms-Related Tyrosine Kinase 4 (FLT4; vascular endothelial growth factor receptor 3). After demonstrating that genistein suppressed neo-angiogenesis in mouse tumors, we examined FLT4 expression in primary CRC and adjacent normal colonic tissue from 60 human subjects, demonstrating that increased FLT4 significantly correlates with increased stage and decreased survival. In summary, we demonstrate for the first time that genistein inhibits human CRC metastasis at dietary, non-toxic, doses. FLT4 is identified as a marker of metastatic disease, and as a response marker for small molecule therapeutics that inhibit CRC metastasis. PMID:25605009

  15. Gamma irradiation inhibits wound induced browning in shredded cabbage.

    PubMed

    Banerjee, Aparajita; Suprasanna, Penna; Variyar, Prasad S; Sharma, Arun

    2015-04-15

    Gamma-radiation induced browning inhibition in minimally processed shredded cabbage stored (10 °C) for up to 8 days was investigated. ?-irradiation (2 kGy) resulted in inhibition of browning as a result of down-regulation (1.4-fold) in phenylalanine ammonia lyase (PAL) gene expression and a consequent decrease in phenylalanine ammonia lyase (PAL) activity. Activity of polyphenol oxidase and peroxidase, total and individual phenolic content as well as o-quinone concentration were, however, unaffected. In the non-irradiated samples, PAL activity increased as a consequence of up-regulation of PAL gene expression after 24 and 48 h by 1.2 and 7.7-fold, respectively, during storage that could be linearly correlated with enhanced quinone formation and browning. Browning inhibition in radiation processed shredded cabbage as a result of inhibition of PAL activity was thus clearly demonstrated. The present work provides an insight for the first time on the mechanism of browning inhibition at both biochemical and genetic level. PMID:25465992

  16. [Mechanisms of algal inhibition by rice straw extract].

    PubMed

    Feng, Jing; Zhu, Qing; Wu, Wei-zhong; Rui, Ke-jian; Li, Yan-bo

    2008-12-01

    An indoor experiment was conducted to investigate the inhibition effects and mechanisms of rice straw extracts to the harmful bloom-forming algae, Microcystis aeruginosa. It was found that there were algae inhibitory chemicals in rice straw. The inhabitation ratio of rice straw extract to Microcystis was 69.3% when stored at a low temperature of - 4 degrees C for 4 days with a concentration of 2.5 g/L. The algal inhibition depends on both chemicals and biological responses from decomposed rice straw extracts. Their relative contributions to the algal inhibition depended on decomposition pathway and time. Algal inhibitory chemicals played more important roles in anaerobic decomposed rice straw extracts than aerobic decomposed ones in the algal-inhibition process. For anaerobically decomposed straw extracts, if stored for 15 and 30 days with the concentration of 1.5 g/L, the inhabitation ratio of rice straw to Microcystis was 83% and 46% respectively. However, for aerobically decomposed straw extracts, the biologic mechanism was more important. The inhibition effects of biologic mechanism increased with the decomposition time. For aerobically decomposed straw extracts, if stored for 15 and 30 days with the concentration of 1.5 g/L, the inhabitation ratio of rice straw to Microcystis was 81% and 93% respectively. PMID:19256371

  17. Combined PDGFR and HDAC Inhibition Overcomes PTEN Disruption in Chordoma

    PubMed Central

    Kassam, Amin B.; Park, Myung-Jin; Gardner, Paul; Prevedello, Daniel; Henry, Stephanie; Horbinski, Craig; Beumer, Jan H.; Tawbi, Hussein; Williams, Brian J.; Shaffrey, Mark E.; Egorin, Merrill J.; Abounader, Roger; Park, Deric M.

    2015-01-01

    Background The majority of chordomas show activation of the platelet-derived growth factor receptor (PDGFR). Based on in vitro intertumoral variation in response to recombinant PDGF protein and PDGFR inhibition, and variable tumor response to imatinib, we hypothesized that chordomas resistant to PDGFR inhibition may possess downstream activation of the pathway. Methods Molecular profiling was performed on 23 consecutive chordoma primary tissue specimens. Primary cultures established from 20 of the 23 specimens, and chordoma cell lines, UCH-1 and UCH-2, were used for in vitro experiments. Results Loss of heterozygosity (LOH) at the phosphatase and tensin homolog (PTEN) locus was observed in 6 specimens (26%). PTEN disruption statistically correlated with increased Ki-67 proliferation index, an established marker of poor outcome for chordoma. Compared to wild type, PTEN deficient chordomas displayed increased proliferative rate, and responded less favorably to PDGFR inhibition. PTEN gene restoration abrogated this growth advantage. Chordomas are characterized by intratumoral hypoxia and local invasion, and histone deacetylase (HDAC) inhibitors are capable of attenuating both hypoxic signaling and cell migration. The combination of PDGFR and HDAC inhibition effectively disrupted growth and invasion of PTEN deficient chordoma cells. Conclusions Loss of heterozygosity of the PTEN gene seen in a subset of chordomas is associated with aggressive in vitro behavior and strongly correlates with increased Ki-67 proliferative index. Combined inhibition of PDGFR and HDAC attenuates proliferation and invasion in chordoma cells deficient for PTEN. PMID:26247786

  18. Inhibition of cyclooxygenase (COX)-2 affects endothelial progenitor cell proliferation

    SciTech Connect

    Colleselli, Daniela; Bijuklic, Klaudija; Mosheimer, Birgit A.; Kaehler, Christian M. . E-mail: C.M.Kaehler@uibk.ac.at

    2006-09-10

    Growing evidence indicates that inducible cyclooxygenase-2 (COX-2) is involved in the pathogenesis of inflammatory disorders and various types of cancer. Endothelial progenitor cells recruited from the bone marrow have been shown to be involved in the formation of new vessels in malignancies and discussed for being a key point in tumour progression and metastasis. However, until now, nothing is known about an interaction between COX and endothelial progenitor cells (EPC). Expression of COX-1 and COX-2 was detected by semiquantitative RT-PCR and Western blot. Proliferation kinetics, cell cycle distribution and rate of apoptosis were analysed by MTT test and FACS analysis. Further analyses revealed an implication of Akt phosphorylation and caspase-3 activation. Both COX-1 and COX-2 expression can be found in bone-marrow-derived endothelial progenitor cells in vitro. COX-2 inhibition leads to a significant reduction in proliferation of endothelial progenitor cells by an increase in apoptosis and cell cycle arrest. COX-2 inhibition leads further to an increased cleavage of caspase-3 protein and inversely to inhibition of Akt activation. Highly proliferating endothelial progenitor cells can be targeted by selective COX-2 inhibition in vitro. These results indicate that upcoming therapy strategies in cancer patients targeting COX-2 may be effective in inhibiting tumour vasculogenesis as well as angiogenic processes.

  19. The flavonone naringenin inhibits chloride secretion in isolated colonic epithelia.

    PubMed

    Collins, Danielle; Kopic, Sascha; Geibel, John P; Hogan, Aisling M; Medani, Mekki; Baird, Alan W; Winter, Desmond C

    2011-10-01

    Studies investigating the activating and inhibitory actions of bioflavonoids on colonic function have yielded conflicting results. At low concentrations, flavonoids may stimulate chloride secretion while at higher concentrations they may have antisecretory actions in the colon. Naringenin (4',5,7-trihydroxyflavanone), found predominantly in citrus fruits, confers a protective effect against colorectal cancer and is purported to modulate secretory function in colonic cell lines. The aim of this study was to investigate the effects of naringenin on ion transport in rat and human colonic mucosae. Naringenin inhibited basal and stimulated chloride secretion in rat and human colonic mucosae mounted in Ussing chambers (IC(50) 330 ?Mol/L and 360 ?Mol/L respectively) and did not alter intracellular cAMP generation. Naringenin inhibited chloride secretion in MQAE (N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide) loaded crypts stimulated with forskolin. In BCECF (2',7'-bis-(2-carboxyethyl)-5-(and 6)-carboxyfluorescein acetoxymethyl ester) loaded crypts, naringenin caused an intracellular acidification (?pH/min=0.05 ± 0.004) which was sensitive to the Na-K-Cl co-transporter (NKCC) inhibitor bumetanide. In addition, the antisecretory effect of naringenin was not inhibited by blockade of barium sensitive basolateral K(+) transporters or by inhibition of Na+/H(+) exchange by amiloride. We propose that the antisecretory action of naringenin is due to inhibition of basolateral NKCC1 in rat and human colon. PMID:21762688

  20. Inhibition of Carcinoma Cell Motility by Epoxyeicosatrienoic Acid (EET) Antagonists

    PubMed Central

    Nithipatikom, Kasem; Brody, Daniel M.; Tang, Alan T.; Manthati, Vijaya L.; Falck, John R.; Williams, Carol L.; Campbell, William B.

    2012-01-01

    Summary Cytochrome P450 (CYP) epoxygenases, CYP2C8, 2C9 and 2J2 mRNAs and proteins, were expressed in prostate carcinoma (PC-3, DU-145 and LNCaP) cells. 11,12-Epoxyeicosatrienoic acid (11,12-EET) was the major arachidonic acid metabolite in these cells. Blocking the EET synthesis by a selective CYP epoxygenase inhibitor (MS-PPOH) inhibited tonic (basal) invasion and migration (motility) while exogenously added EETs induced cell motility in a concentration-dependent manner. An EGFR kinase inhibitor (AG494) or a PI3 kinase inhibitor (LY294002) inhibited cell migration and reduced 11,12-EET-induced cell migration. Importantly, synthetic EET antagonists (14,15-EEZE, 14,15-EEZE-PEG and 14,15-EEZE-mSI) inhibited EET-induced cell invasion and migration. 11,12-EET induced cell stretching and myosin-actin microfilament formation as well as increased phosphorylation of EGFR and Akt (Ser473) while 14,15-EEZE inhibited these effects. These results suggest that EETs induce and EET antagonists inhibit cell motility, possibly by putative EET receptor-mediated EGFR and PI3K/Akt pathways, and suggest EET antagonists as potential therapeutic agents for prostate cancer. PMID:20804500

  1. Pyridinylquinazolines Selectively Inhibit Human Methionine Aminopeptidase-1 in Cells

    PubMed Central

    Zhang, Feiran; Bhat, Shridhar; Gabelli, Sandra B.; Chen, Xiaochun; Miller, Michelle S.; Nacev, Benjamin A.; Cheng, Yim Ling; Meyers, David J.; Tenney, Karen; Shim, Joong Sup; Crews, Phillip; Amzel, L. Mario; Ma, Dawei; Liu, Jun O.

    2013-01-01

    Methionine aminopeptidases (MetAPs) which remove the initiator methionine from nascent peptides are essential in all organisms. While MetAP2 has been demonstrated to be a therapeutic target for inhibiting angiogenesis in mammals, MetAP1 seems to be vital for cell proliferation. Our earlier efforts identified two structural classes of human MetAP1 (HsMetAP1)-selective inhibitors (1–4). But all of them failed to inhibit cellular HsMetAP1. Using Mn(II) or Zn(II) to activate HsMetAP1, we found that 1–4 could only effectively inhibit purified HsMetAP1 in the presence of physiologically unachievable concentrations of Co(II). In an effort to seek Co(II)-independent inhibitors, a novel structural class containing a 2-(pyridin-2-yl)quinazoline core has been discovered. Many compounds in this class potently and selectively inhibited HsMetAP1 without Co(II). Subsequently, we demonstrated that 11j, an auxiliary metal-dependent inhibitor, effectively inhibited HsMetAP1 in primary cells. This is the first report that an HsMetAP1-selective inhibitor is effective against its target in cells. PMID:23634668

  2. IGF-1 receptor inhibition by picropodophyllin in medulloblastoma

    SciTech Connect

    Ohshima-Hosoyama, Sachiko; Hosoyama, Tohru; Nelon, Laura D.; Keller, Charles; Department of Pediatrics, University of Texas Health Science Center, San Antonio, TX 78229; Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio, TX 78229

    2010-09-03

    Research highlights: {yields} Igf1r is overexpressed and activated in a Sonic Hedgehog driven model of medulloblastoma. {yields} Picropodophyllin targets and abrogates IGF signaling in medulloblastoma. {yields} Picropodophyllin inhibits medulloblastoma tumor cell growth by induction of apoptosis. -- Abstract: The insulin-like growth factor-1 receptor (Igf1r) is a multifunctional membrane-associated tyrosine kinase associated with regulation of transformation, proliferation, differentiation and apoptosis. Increased IGF pathway activity has been reported in human and murine medulloblastoma. Tumors from our genetically-engineered medulloblastoma mouse model over-express Igf1r, and thus this mouse model is a good platform with which to study the role of Igf1r in tumor progression. We hypothesize that inhibition of IGF pathway in medulloblastoma can slow or inhibit tumor growth and metastasis. To test our hypothesis, we tested the role of IGF in tumor growth in vitro by treatment with the tyrosine kinase small molecule inhibitor, picropodophyllin (PPP), which strongly inhibits the IGF pathway. Our results demonstrate that PPP-mediated downregulation of the IGF pathway inhibits mouse tumor cell growth and induces apoptotic cell death in vitro in primary medulloblastoma cultures that are most reflective of tumor cell behavior in vivo.

  3. Nitrosative stress suppresses checkpoint activation after DNA synthesis inhibition

    PubMed Central

    Tomko, Robert J.; Azang-Njaah, Ndang N.; Lazo, John S.

    2009-01-01

    DNA synthesis is promoted by the dephosphorylation and activation of cyclin-dependent kinase 2 (Cdk2) complexes by Cdc25A. Nitrosative stress suppresses Cdk2 dephosphorylation by Cdc25A in vitro and inhibits Cdc25A protein translation in cells, but the effects on S-phase progression remain unexamined. Herein we report that nitrosative stress catalyzed by inducible nitric oxide (•NO) synthase (iNOS) or the chemical nitrosant S-nitrosocysteine ethyl ester (SNCEE) rapidly inhibited DNA synthesis concomitant with Cdc25A loss. Surprisingly, this inhibition of DNA synthesis was refractory to ectopic expression of Cdc25A or a Cdc25-independent Cdk2 mutant. Nitrosative stress inhibited DNA synthesis without activating checkpoint signaling, thus distinguishing it from S-phase arrest mediated by other reactive •NO-derived species. The apparent lack of checkpoint activation was due to an active suppression because accumulation of pSer345-Chk1, pThr68-Chk2, and ?H2AX was inhibited by nitrosative stress in cells exposed to DNA damage or replication inhibitors. We speculate that failure to activate the S-phase checkpoint in precancerous cells undergoing nitrosative stress may elevate the risk of transmitting damaged genomes to daughter cells upon cell cycle reentry. PMID:19158509

  4. Organic peroxides inhibit neutrophil leukotriene B4 biosynthesis.

    PubMed

    Okazaki, I J; Newman, L M; Allen, D W

    1992-12-01

    Leukotriene B4, an autacoid metabolite of arachidonic acid produced by polymorphonuclear neutrophils, induces chemokinesis, chemotaxis, and adhesion of these cells at sites of inflammation. Because neutrophil infiltration is a self-limited process, we hypothesized that oxidized lipid products of neutrophil-damaged tissue might inhibit leukotriene B4 biosynthesis, thereby preventing additional neutrophil infiltration and limiting peroxidative tissue damage. Erythrocyte ghosts exposed to a hydrogen peroxide-generating system served as a model of peroxidized tissue in inflammation and inhibited neutrophil leukotriene B4 production by 50% compared with unoxidized ghosts. Organic peroxides, including tert-butylhydroperoxide, peracetic acid, and linoleic hydroperoxide, resembling the product(s) of tissue membrane peroxidation in lipid solubility and catalase resistance, inhibited leukotriene B4 biosynthesis in a dose-dependent manner (50% inhibitory concentration of 3.9 microM compared to 530 microM for H2O2). Biosynthetic steps prior to the 5-lipoxygenase did not appear to be the site of inhibition. Likewise, the step after the 5-lipoxygenase, the leukotriene A4 hydrolase, was not primarily involved. Thus a possible mechanism for controlling the influx of neutrophils and their oxidative damage during inflammation may be inhibition of the 5-lipoxygenase by catalase-resistant lipid peroxides released by tissue membranes. PMID:1334502

  5. Pharmacodynamics of telomerase inhibition and telomere shortening by noncytotoxic suramin.

    PubMed

    Gan, Yuebo; Lu, Jie; Yeung, Bertrand Z; Cottage, Christopher T; Wientjes, M Guillaume; Au, Jessie L-S

    2015-01-01

    We reported that suramin is an effective chemosensitizer at noncytotoxic concentrations (<50 ?M); this effect was observed in multiple types of human xenograft tumors in vitro and in vivo. Clinical evaluation of noncytotoxic suramin is ongoing. Because (a) suramin inhibits reverse transcriptase, (b) telomerase is a reverse transcriptase, and (c) inhibition of telomerase enhances tumor chemosensitivity, we studied the pharmacodynamics of noncytotoxic suramin on telomerase activity and telomere length in cultured cells and tumors grown in animals. In three human cancer cells that depend on telomerase for telomere maintenance (pharynx FaDu, prostate PC3, breast MCF7), suramin inhibited telomerase activity in cell extracts and intact cells at concentrations that exhibited no cytotoxicity (IC50 of telomerase was between 1 and 3 ?M vs. >60 ?M for cytotoxicity), and continuous treatment at 10-25 ?M for 6 weeks resulted in gradual telomere shortening (maximum of 30%) and cell senescence (measured by ?-galactosidase activity and elevation of mRNA levels of two senescence markers p16 and p21). In contrast, noncytotoxic suramin did not shorten the telomere in telomerase-independent human osteosarcoma Saos-2 cells. In mice bearing FaDu tumors, treatment with noncytotoxic suramin for 6 weeks resulted in telomere erosion in >95% of the tumor cells with an average telomere shortening of >40%. These results indicate noncytotoxic suramin inhibits telomerase, shortens telomere and induces cell senescence, and suggest telomerase inhibition as a potential mechanism of its chemosensitization. PMID:25425294

  6. Inhibition of renal Na+, K+-adenosine triphosphatase by gentamicin

    SciTech Connect

    Williams, P.D.; Trimble, M.E.; Crespo, L.; Holohan, P.D.; Freedman, J.C.; Ross, C.R.

    1984-11-01

    Inhibition of renal Na+,K+-adenosine triphosphatase is an early biochemical manifestation of gentamicin treatment in rats. Studies with isolated, perfused rat kidneys in filtering and nonfiltering modes indicate that gentamicin is transported across the brush border membrane before enzyme inhibition. The drug caused enzyme inhibition (42%) only in filtering kidneys, and this inhibition was blocked by spermine, an inhibitor of gentamicin binding. In purified rat renal basolateral membranes, bound (/sup 3/H)gentamicin was displaced 88% by unlabeled gentamicin. After in vivo exposure to (/sup 3/H)gentamicin, the radioactivity associated with the isolated basolateral membranes was displaced only 46% by unlabeled drug. These results suggest that inhibition of renal Na+,K+-adenosine triphosphatase by gentamicin is probably due to an interaction at the cytoplasmic face of the basolateral membrane. Scatchard plots of (/sup 3/H)gentamicin binding to basolateral and brush border membranes revealed a single class of noninteracting sites in each membrane. Gentamicin did not change the bulk membrane lipid fluidity, as estimated by the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene.

  7. Dual inhibition of acetylcholinesterase and butyrylcholinesterase enzymes by allicin

    PubMed Central

    Kumar, Suresh

    2015-01-01

    Objectives: The brain of mammals contains two major form of cholinesterase enzymes, acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE). The dual inhibition of these enzymes is considered as a promising strategy for the treatment of neurological disorder such as Alzheimer's disease (AD), senile dementia, ataxia, and myasthenia gravis. The present study was undertaken to explore the anticholinesterase inhibition property of allicin. Materials and Methods: An assessment of cholinesterase inhibition was carried out by Ellman's assay. Results: The present study demonstrates allicin, a major ingredient of crushed garlic (Allium sativum L.) inhibited both AChE and BuChE enzymes in a concentration-dependent manner. For allicin, the IC50 concentration was 0.01 mg/mL (61.62 ?M) for AChE and 0.05 ± 0.018 mg/mL (308.12 ?M) for BuChE enzymes. Conclusions: Allicin shows a potential to ameliorate the decline of cognitive function and memory loss associated with AD by inhibiting cholinesterase enzymes and upregulate the levels of acetylcholine (ACh) in the brain. It can be used as a new lead to target AChE and BuChE to upregulate the level of ACh which will be useful in alleviating the symptoms associated with AD. PMID:26288480

  8. IGFBP-3, hypoxia and TNF-{alpha} inhibit adiponectin transcription

    SciTech Connect

    Zappala, Giovanna; Rechler, Matthew M.; Clinical Endocrinology Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD

    2009-05-15

    The thiazolidinedione rosiglitazone, an agonist ligand for the nuclear receptor PPAR-{gamma}, improves insulin sensitivity in part by stimulating transcription of the insulin-sensitizing adipokine adiponectin. It activates PPAR-{gamma}-RXR-{alpha} heterodimers bound to PPAR-{gamma} response elements in the adiponectin promoter. Rosiglitazone-stimulated adiponectin protein synthesis in 3T3-L1 mouse adipocytes has been shown to be inhibited by IGFBP-3, which can be induced by hypoxia and the proinflammatory cytokine, TNF-{alpha}, two inhibitors of adiponectin transcription. The present study demonstrates that IGFBP-3, the hypoxia-mimetic agent cobalt chloride, and TNF-{alpha} inhibit rosiglitazone-induced adiponectin transcription in mouse embryo fibroblasts that stably express PPAR-{gamma}2. Native IGFBP-3 can bind RXR-{alpha} and inhibited rosiglitazone stimulated promoter activity, whereas an IGFBP-3 mutant that does not bind RXR-{alpha} did not. These results suggest that IGFBP-3 may mediate the inhibition of adiponectin transcription by hypoxia and TNF-{alpha}, and that IGFBP-3 binding to RXR-{alpha} may be required for the observed inhibition.

  9. Stereoselective effects of MDMA on inhibition of monoamine uptake

    SciTech Connect

    Steele, T.D.; Nichols, D.E.; Yim, G.K.W.

    1986-03-05

    The R(-)-isomers of hallucinogenic phenylisopropylamines are most active, whereas the S(+)-enantiomers of amphetamine (AMPH) and methylenedioxymethamphetamine (MDMA) are more potent centrally. To determine if MDMA exhibits stereoselective effects at the biochemical level that resemble either those of amphetamine or the potent hallucinogen 2,5-dimethoxy-4-methylamphetamine (DOM), the ability of the isomers of MDMA, AMPH and DOM to inhibit uptake of radiolabelled monoamines into synaptosomes was measured. AMPH was more potent than MDMA in inhibiting uptake of /sup 3/H-norepinephrine (NE) into hypothalamic synaptosomes and /sup 3/H-dopamine (DA) into striatal synaptosomes. The S(+)-isomer was more active in each case. MDMA was more potent than AMPH in inhibiting uptake of /sup 3/H-serotonin (5-HT) into hippocampal synaptosomes and exhibited a high degree of stereoselectivity, in favor of the S(+)-isomer. DOM showed only minimal activity in inhibiting uptake of any monoamine (IC/sub 50/ > 10/sup -5/M). These results suggest that MDMA exhibits stereoselective effects similar to those of amphetamine on monoamine uptake inhibition, a parameter that is unrelated to the mechanism of action of the hallucinogen DOM.

  10. Inhibition by Methylphenidate of Transport Across the Yeast Cell Membrane

    PubMed Central

    Spoerl, Edward; Doyle, R. J.

    1968-01-01

    The influence of methylphenidate on glycolysis in yeast cells was studied to describe more fully the nature of the reactions in which this drug participates. CO2 production and O2 uptake of yeast cells was inhibited 75% by a 10 mm concentration of the compound. This effect, with glucose as a substrate, occurred at pH 7.0, but not at pH 4.5. Kinetic data indicated that the reaction was noncompetitive and complex; the methylphenidate effect on CO2 production could not readily be reversed. Glycolysis by cell-free extracts was not inhibited at the 10-mm concentration, but was affected at 100 mm. Utilization of O2 with maltose and ethyl alcohol as substrates also was reduced. Entry into the cells of a number of different carbohydrates and of glycine was inhibited to different degrees. The loss from suspended cells of materials absorbing at 280 nm was reduced, and the efflux of sorbose, arabinose, and lactose was decreased. Thus, transport into and out of the cells was inhibited and leakage, or permeability, was reduced. It is hypothesized that methylphenidate reacts with a cell membrane constituent, or constituents, and inhibits glycolysis by blocking sugar passage. PMID:5732507

  11. Inhibition by methylphenidate of transport across the yeast cell membrane.

    PubMed

    Spoerl, E; Doyle, R J

    1968-09-01

    The influence of methylphenidate on glycolysis in yeast cells was studied to describe more fully the nature of the reactions in which this drug participates. CO(2) production and O(2) uptake of yeast cells was inhibited 75% by a 10 mm concentration of the compound. This effect, with glucose as a substrate, occurred at pH 7.0, but not at pH 4.5. Kinetic data indicated that the reaction was noncompetitive and complex; the methylphenidate effect on CO(2) production could not readily be reversed. Glycolysis by cell-free extracts was not inhibited at the 10-mm concentration, but was affected at 100 mm. Utilization of O(2) with maltose and ethyl alcohol as substrates also was reduced. Entry into the cells of a number of different carbohydrates and of glycine was inhibited to different degrees. The loss from suspended cells of materials absorbing at 280 nm was reduced, and the efflux of sorbose, arabinose, and lactose was decreased. Thus, transport into and out of the cells was inhibited and leakage, or permeability, was reduced. It is hypothesized that methylphenidate reacts with a cell membrane constituent, or constituents, and inhibits glycolysis by blocking sugar passage. PMID:5732507

  12. Cyclosporin A inhibits CD40 ligand expression in T lymphocytes.

    PubMed Central

    Fuleihan, R; Ramesh, N; Horner, A; Ahern, D; Belshaw, P J; Alberg, D G; Stamenkovic, I; Harmon, W; Geha, R S

    1994-01-01

    The ligand for CD40 is expressed on activated T lymphocytes and delivers contact-dependent activation signals to B lymphocytes. The mechanisms regulating CD40 ligand gene expression are largely unknown. Optimal expression of CD40 ligand required activation of protein kinase C and a rise in intracellular calcium concentration. CD40 ligand expression was inhibited by pretreatment of T cells with cyclosporin A. Cyclosporin A analogues inhibited CD40 ligand expression with a potency mirroring the ability of each compound to inhibit calcineurin activity, indicating that calcineurin plays a key role in CD40 ligand gene expression. Cyclosporin A inhibited IL-4-driven CD40 ligand-dependent IgE isotype switching in PBMC but did not inhibit IgE synthesis induced by CD40 mAb plus IL-4. PBMC derived from transplant patients receiving cyclosporin A failed to express CD40 ligand upon stimulation. These results suggest that patients receiving cyclosporin A may be deficient in CD40 ligand-dependent T cell help. Images PMID:7907604

  13. Geranylgeranylacetone inhibits ovarian cancer progression in vitro and in vivo

    SciTech Connect

    Hashimoto, Kae; Morishige, Ken-ichirou . E-mail: mken@gyne.med.osaka-u.ac.jp; Sawada, Kenjiro; Ogata, Seiji; Tahara, Masahiro; Shimizu, Shoko; Sakata, Masahiro; Tasaka, Keiichi; Kimura, Tadashi

    2007-04-27

    Geranylgeranylacetone (GGA), an isoprenoid compound, is an anti-ulcer drug developed in Japan. In our previous study, GGA was shown to inhibit ovarian cancer invasion by attenuating Rho activation [K. Hashimoto, K. Morishige, K. Sawada, M. Tahara, S. Shimizu, M. Sakata, K. Tasaka, Y. Murata, Geranylgeranylacetone inhibits lysophosphatidic acid-induced invasion of human ovarian carcinoma cells in vitro. Cancer 103 (2005) 1529-1536.]. In the present study, GGA treatment inhibited ovarian cancer progression in vitro and suppressed the tumor growth and ascites in the in vivo ovarian cancer model. In vitro analysis, treatment of cancer cells by GGA resulted in the inhibition of cancer cell proliferation, the inactivation of Ras, and the suppression of tyrosine phosphorylation of mitogen-activated protein kinase (MAPK). In conclusion, this is the first report that GGA inhibited ovarian cancer progression and the anti-tumor effect by GGA is, at least in part, derived not only from the suppression of Rho activation but also Ras-MAPK activation.

  14. Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide.

    PubMed Central

    Hyman, M R; Kim, C Y; Arp, D J

    1990-01-01

    Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined. Low concentrations of CS2 (less than 400 microM) produced a time-dependent inhibition of ammonia-dependent O2 uptake but did not inhibit hydrazine-oxidizing activity. CS2 also produced distinct changes in difference spectra of whole cells. These results suggest that ammonia monooxygenase (AMO) is the site of action of CS2. Unlike the case for thiourea and acetylene, saturating concentrations of CS2 did not fully inhibit AMO, and the inhibition resulted in a low but significant rate of ammonia-dependent O2 uptake. The effects of CS2 were not competitive with respect to ammonia concentration, and the inhibition by CS2 did not require the turnover of AMO to take effect. The ability of CS2-treated cells to incorporate [14C]acetylene into the 28-kilodalton polypeptide of AMO was used to demonstrate that the effects of CS2 are compatible with a mode of action which involves a reduction of the rate of turnover of AMO without effects on the catalytic mechanism. It is proposed that CS2 may act on AMO by reversibly reacting with a suitable nucleophilic amino acid in close proximity to the active site copper. Images PMID:2118501

  15. Lens epithelial inhibition by PMMA optic: implications for lens design.

    PubMed

    Santos, B A; Pastora, R; DelMonte, M A; O'Donnell, F E

    1986-01-01

    It has been a clinical impression that posterior chamber lens implants in some way inhibit opacification of the posterior lens capsule after extracapsular cataract extraction. The mechanism of this inhibition is unclear; it may be related to mechanical contact or blockage of migration of lens epithelial cells, or possibly to the leeching of toxic factors from the lens itself. A better understanding of the exact mechanism of opacification inhibition may have important clinical implications for intraocular lens design. For example, some lens designs that facilitate Nd:YAG capsulotomy by physically separating the posterior chamber lens and the posterior capsule may result in less inhibition and in fact more opacification of posterior capsules. We performed in vitro tissue culture studies of the effect of the polymethylmethacrylate (PMMA) optic of a planoconvex intraocular lens on cultured rabbit lens epithelium. These studies demonstrated both inhibition of lens epithelial migration beneath the PMMA optic (plano side down) as well as metaplasia and necrosis of lens cells growing directly beneath the optic. The clinical implications of these studies for intraocular lens design are discussed. PMID:3958946

  16. Development of an inhibitive enzyme assay for copper.

    PubMed

    Shukor, M Y; Bakar, N A; Othman, A R; Yunus, I; Shamaan, N A; Syed, M A

    2009-01-01

    In this work the development of an inhibitive assay for copper using the molybdenum-reducing enzyme assay is presented. The enzyme is assayed using 12-molybdophosphoric acid at pH 5.0 as an electron acceptor substrate and NADH as the electron donor substrate. The enzyme converts the yellowish solution into a deep blue solution. The assay is based on the ability of copper to inhibit the molybdenum-reducing enzyme from the molybdate-reducing Serratia sp. Strain DRY5. Other heavy metals tested did not inhibit the enzyme at 10 mg l(-1). The best model with high regression coefficient to measure copper inhibition is one-phase binding. The calculated IC50 (concentration causing 50% inhibition) is 0.099 mg l(-1) and the regression coefficient is 0.98. The comparative LC50, EC50 and IC50 data for copper in different toxicity tests show that the IC50 value for copper in this study is lower than those for immobilized urease, bromelain, Rainbow trout, R. meliloti, Baker's Yeast dehydrogenase activity Spirillum volutans, P. fluorescens, Aeromonas hydrophilia and synthetic activated sludge assays. However the IC50 value is higher than those for Ulva pertusa and papain assays, but within the reported range for Daphnia magna and Microtox assays. PMID:20112861

  17. Emodin inhibits tonic tension through suppressing PKC?-mediated inhibition of myosin phosphatase in rat isolated thoracic aorta

    PubMed Central

    Lim, Kyung-Min; Kwon, Jae-Hyuk; Kim, Keunyoung; Noh, Ji-Yoon; Kang, Seojin; Park, Jung-Min; Lee, Moo-Yeol; Bae, Ok-Nam; Chung, Jin-Ho

    2014-01-01

    Background and Purpose Dysregulated tonic tension and calcium sensitization in blood vessels has frequently been observed in many cardiovascular diseases. Despite a huge therapeutic potential, little is known about natural products targeting tonic tension and calcium sensitization. Experimental Approach We screened natural products for inhibitory effects on vasoconstriction using the rat isolated thoracic aorta and found that an anthraquinone derivative, emodin, attenuated tonic tension. Organ bath system, primary vascular smooth muscle cells, confocal microscopy and Western blot analysis were employed to demonstrate the suppressive effects of emodin on PKC?-mediated myosin phosphatase inhibition. Key Results Emodin, an active ingredient of Polygonum multiflorum extract, inhibited phenylephrine-induced vasoconstriction in rat isolated thoracic aorta, and inhibited vasoconstriction induced by 5-HT and endothelin-1. It also generally suppressed vasoconstrictions mediated by voltage-operated, store-operated calcium channels and intracellular calcium store. However, emodin did not affect agonist-induced calcium increases in primary smooth muscle cells. In contrast, post-treatment with emodin following phenylephrine stimulation potently suppressed tonic tension in rat aortic rings. Western blot analysis revealed that emodin inhibited phenylephrine-induced phospho-myosin light chain (pMLC) and the phosphorylation of myosin-targeting subunit and C-kinase-activated protein phosphatase-1 inhibitor (CPI-17). This was mediated by selective inhibition of PKC?, whereas PKC? was not involved. Conclusion and Implications Emodin attenuates tonic tension through the blockade of PKC? and CPI-17-mediated MLC-phosphatase inhibition. This new mode of action for the suppression of tonic tension and structural insights into PKC? inhibition revealed by emodin may provide new information for the development of modulators of tonic tension and for the treatment of hypertension. PMID:24909118

  18. Structure of a thermophilic F1-ATPase inhibited by an ?-subunit: deeper insight into the ?-inhibition mechanism.

    PubMed

    Shirakihara, Yasuo; Shiratori, Aya; Tanikawa, Hiromi; Nakasako, Masayoshi; Yoshida, Masasuke; Suzuki, Toshiharu

    2015-08-01

    F1-ATPase (F1) is the catalytic sector in F(o)F1-ATP synthase that is responsible for ATP production in living cells. In catalysis, its three catalytic ?-subunits undergo nucleotide occupancy-dependent and concerted open-close conformational changes that are accompanied by rotation of the ?-subunit. Bacterial and chloroplast F1 are inhibited by their own ?-subunit. In the ?-inhibited Escherichia coli F1 structure, the ?-subunit stabilizes the overall conformation (half-closed, closed, open) of the ?-subunits by inserting its C-terminal helix into the ?3?3 cavity. The structure of ?-inhibited thermophilic F1 is similar to that of E. coli F1, showing a similar conformation of the ?-subunit, but the thermophilic ?-subunit stabilizes another unique overall conformation (open, closed, open) of the ?-subunits. The ?-C-terminal helix 2 and hook are conserved between the two structures in interactions with target residues and in their positions. Rest of the ?-C-terminal domains are in quite different conformations and positions, and have different modes of interaction with targets. This region is thought to serve ?-inhibition differently. For inhibition, the ?-subunit contacts the second catches of some of the ?- and ?-subunits, the N- and C-terminal helices, and some of the Rossmann fold segments. Those contacts, as a whole, lead to positioning of those ?- and ?- second catches in ?-inhibition-specific positions, and prevent rotation of the ?-subunit. Some of the structural features are observed even in IF1 inhibition in mitochondrial F1. PMID:26032434

  19. Characteristics of the blood pressure lowering action of renin inhibition and comparison with angiotensin converting enzyme inhibition.

    PubMed

    Blaine, E H

    1989-04-01

    Mean arterial blood pressure (MAP) was 100 +/- 4 mmHg in a group (n = 3) of conscious sodium-deficient dogs. A 3-day infusion of the renin inhibitor isovaleryl -His-Pro-Phe-His-Sta-Leu-Phe-NH2 (SCRIP) lowered MAP to an average of 79 +/- 4 mmHg. Termination of the infusion resulted in a prompt rise in MAP to 100 +/- 5 mmHg but plasma renin activity (PRA), which was 22 +/- 2 ng angiotensin (Ang) l/ml per h before the infusion, recovered only to 5 +/- 1 ng Ang l/ml per h during the same time (4 h after infusion). In other experiments in sodium-deficient dogs, a direct comparison was made between inhibition of PRA and the reduction of blood pressure. Over the dose range 0.1-2 micrograms/kg per min, PRA was inhibited in a dose-related manner, but MAP was not reduced. At dose levels beginning an order of magnitude higher (e.g. 20-160 g/kg per min), PRA was completely inhibited and there was a dose-related fall in MAP. These data suggest that there is no correlation between inhibition of PRA and the reduction in blood pressure in chronically sodium-deficient dogs. In other studies comparing renin inhibition with angiotensin converting enzyme (ACE) inhibition, there was evidence for greater efficacy of ACE inhibition in conscious sodium-deficient dogs, but no evidence of any difference in one-kidney, one clip hypertensive dogs. PMID:2666614

  20. Complete inhibition of creatine kinase in isolated perfused rat hearts

    SciTech Connect

    Fossel, E.T.; Hoefeler, H.

    1987-01-01

    Transient exposure of an isolated isovolumic perfused rat heart to low concentrations (0.5 mM) of perfusate-born iodoacetamide resulted in complete inhibition of creatine kinase and partial inhibition of glyceraldehyde-3-phosphate dehydrogenase in the heart. At low levels of developed pressure, hearts maintained mechanical function, ATP, and creatine phosphate levels at control values. However, iodoacetamide-inhibited hearts were unable to maintain control values of end diastolic pressure or peak systolic pressure as work load increased. Global ischemia resulted in loss of all ATP without loss of creatine phosphate, indicating lack of active creatine kinase. These results indicate that isovolumic perfused rat hearts are able to maintain normal function and normal levels of high-energy phosphates without active creatine kinase at low levels of developed pressure. /sup 31/P-NMR of the heart was carried out.

  1. Ethanol inhibits mitogen-induced calcium mobilization in mouse splenocytes

    SciTech Connect

    Yoshitatsu Sei; McIntyre, T.; Skolnick, P.; Arora, P.K. )

    1992-01-01

    Ethanol inhibited the mitogen-induced initial increase in cytoplasmic free-calcium (Ca{sup 2+})i in mouse splenocytes. This effect was concentration-dependent, reversible, and observed at pharmacologically relevant concentrations. Other short-chain alcohols such as propanol, butanol, and pentanol also inhibited this mitogen-induced increase in (Ca{sup 2+})i. The potencies of these alcohols to produce this effect were highly correlated with their membrane/buffer partition coefficients. Analysis of mouse splenocyte subpopulations demonstrated that this effect was manifest in both B and T lymphocytes. Within T lymphocyte subpopulations, both CD4{sup +} and CD8{sup +} T cells were affected. These results suggest that the inhibition of (Ca{sup 2+})i increase may be an early event mediating ethanol-induced immunosuppression and that this may be a predisposing factor to infection and malignancies associated with alcoholism.

  2. Mechanism of inhibition of ribonucleotide reductase with motexafin gadolinium (MGd)

    SciTech Connect

    Zahedi Avval, Farnaz; Berndt, Carsten; Pramanik, Aladdin; Holmgren, Arne

    2009-02-13

    Motexafin gadolinium (MGd) is an expanded porphyrin anticancer agent which selectively targets tumor cells and works as a radiation enhancer, with promising results in clinical trials. Its mechanism of action is oxidation of intracellular reducing molecules and acting as a direct inhibitor of mammalian ribonucleotide reductase (RNR). This paper focuses on the mechanism of inhibition of RNR by MGd. Our experimental data present at least two pathways for inhibition of RNR; one precluding subunits oligomerization and the other direct inhibition of the large catalytic subunit of the enzyme. Co-localization of MGd and RNR in the cytoplasm particularly in the S-phase may account for its inhibitory properties. These data can elucidate an important effect of MGd on the cancer cells with overproduction of RNR and its efficacy as an anticancer agent and not only as a general radiosensitizer.

  3. Indomethacin derivatives as tubulin stabilizers to inhibit cancer cell proliferation.

    PubMed

    Chennamaneni, Snigdha; Gan, Chunfang; Lama, Rati; Zhong, Bo; Su, Bin

    2016-01-15

    Cyclooxygenase (COX) inhibitor Indomethacin analogs exhibited more potent cancer cell growth inhibition and apoptosis inducing activities than the parental compound. The anti-proliferative mechanism investigation of the analogs revealed that they inhibited tubulin polymerization at high concentrations whereas enhanced polymerization at low concentrations. The two opposite activities might antagonize each other and impaired the anti-proliferative activity of the derivatives eventually. In this study, we further performed lead optimization based on the structure activity relationship (SAR) generated. One of the new Indomethacin derivatives compound 11 {2-(4-(benzyloxy)phenyl)-N-(1-(4-bromobenzoyl)-3-(2-((2-(dimethylamino)ethyl)amino)-2-oxoethyl)-2-methyl-1H-indol-5-yl)acetamide} inhibited the proliferation of a panel of cancer cell lines with IC50s at the sub-micromole levels. Further study revealed that the compound only enhanced tubulin polymerization and was a tubulin stabilizer. PMID:26712098

  4. NOTCH INHIBITION AS A PROMISING NEW APPROACH TO CANCER THERAPY

    PubMed Central

    Purow, Benjamin

    2012-01-01

    The Notch pathway powerfully influences stem cell maintenance, development and cell fate and is increasingly recognized for the key roles it plays in cancer. Notch promotes cell survival, angiogenesis and treatment resistance in numerous cancers, making it a promising target for cancer therapy. It also crosstalks with other critical oncogenes, providing a means to affect numerous signaling pathways with one intervention. While the gamma-secretaase inhibitors are the only form of Notch inhibitors in clinical trials, other forms of Notch inhibition have been developed or are theoretically feasible. In this chapter we review the rationales for Notch inhibition in cancer and then discuss in detail the various modalities for Notch inhibition, both current and speculative. PMID:22399357

  5. ATP level and caffeine efficiency on cytokinesis inhibition in plants.

    PubMed

    López-Sáez, J F; Mingo, R; González-Fernández, A

    1982-06-01

    Plant cytokinesis appears to be a topographically organized process of exocytosis. Golgi vesicles which contain cell wall precursors are translocated during telophase, by interzonal microtubules, to the equatorial region of the mitotic apparatus where they fuse with each other giving rise to the new cell wall. Caffeine inhibits cytokinesis by hindering Golgi vesicle coalescence. The present results demonstrate that treatments which increase the cellular ATP level (adenosine, cycloheximide and anisomycin) counteract caffein-induced cytokinesis inhibition in meristem cells of onion root tips (Allium cepa L.), while treatments which decrease ATP level potentiate this caffeine effect (dinitrophenol, fluoroacetate, low oxygen tensions, etc.). We postulate that caffeine, in competition with the cellular ATP level, blocks cell plate formation by inhibiting a certain ATPase activity required for membrane fusion of Golgi vesicles. PMID:7117265

  6. Combined product and substrate inhibition equation for cellobiase

    SciTech Connect

    Hong, J.; Ladisch, M.R.; Gong, C.S.; Wankat, P.C.; Tsao, G.T.

    1981-12-01

    Cellobiase is a beta-glucosidase which hydrolyzes cellobiose to glucose and is known to be subject to both product and substrate inhibition. This work reports a model which combines both product and substrate inhibition effects for cellobiase isolated from a commercial preparation of Trichoderma viride from Miles Laboratories (Elkhart, IN). An integrated rate equation is presented which predicts the trends of time courses for hydrolyses of cellobiose at concentrations ranging from 14.6-146 mM cellobiose. The constants used in the model (determined from initial rate data) are compared to those reported for cellobiase obtained from other sources of Trichoderma viride. Most notable in this comparison is the apparently higher activity and reduced inhibition of this enzyme compared to other sources of cellobiase. (Refs. 15).

  7. Inhibition of human polymorphonuclear leukocyte chemotaxis by oxygenated sterol compounds

    SciTech Connect

    Gordon, L.I.; Bass, J.; Yachnin, S.

    1980-07-01

    When preincubated with certain oxygenated sterol compounds in lipoprotein-depleted serum (20% (vol/vol)), human polymorphonuclear leukocytes show inhibition of chemotaxis toward the synthetic dipeptide N-formylmethionylphenylalinine without alteration of random movement or loss of cell viability. These effects can occur at sterol concentrations as low as 6.25 ..mu..M and after as little as 5 min of preincubation, but they are increased at higher concentrations and longer preincubation times. The inhibition can be almost completely reversed by preincubation in lipoprotein-replete serum (human AB serum, 20% (vol/vol)) and may be partially corrected by addition of free cholesterol (0.125 mM) to the medium. These effects are unlikely to be due to inhibition of cellular sterol synthesis, competition for chemotaxin membrane binding sites, or deactivation of the leukocytes but they may be a consequence of insertion of the sterol molecule into the leukocyte plasma membranes.

  8. Modeling of laccase inhibition by formetanate pesticide using theoretical approaches.

    PubMed

    Martins, Ana C V; Ribeiro, Francisco W P; Zanatta, Geancarlo; Freire, Valder N; Morais, Simone; de Lima-Neto, Pedro; Correia, Adriana N

    2016-04-01

    The inhibition of laccase enzymatic catalytic activity by formetanate hydrochloride (FMT) was investigated by cyclic voltammetry and by quantum chemical calculations based on density functional theory with a protein fragmentation approach. The cyclic voltammograms were obtained using a biosensor prepared by enzyme immobilization on gold electrodes modified with gold nanoparticles and 4-aminophenol as the target molecule. The decrease in the peak current in the presence of FMT was used to characterize the inhibition process. The calculations identified Asp206 as the most relevant moiety in the interaction of FMT with the laccase enzymatic ligand binding domain. The amino acid residue Cys453 was important, because the Cys453-FMT interaction energy was not affected by the dielectric constant, although it was not a very close residue. This study provides an overview of how FMT inhibits laccase catalytic activity. PMID:26720841

  9. Ribavirin Inhibits Parrot Bornavirus 4 Replication in Cell Culture

    PubMed Central

    Musser, Jeffrey M. B.; Heatley, J. Jill; Koinis, Anastasia V.; Suchodolski, Paulette F.; Guo, Jianhua; Escandon, Paulina; Tizard, Ian R.

    2015-01-01

    Parrot bornavirus 4 is an etiological agent of proventricular dilatation disease, a fatal neurologic and gastrointestinal disease of psittacines and other birds. We tested the ability of ribavirin, an antiviral nucleoside analog with antiviral activity against a range of RNA and DNA viruses, to inhibit parrot bornavirus 4 replication in duck embryonic fibroblast cells. Two analytical methods that evaluate different products of viral replication, indirect immunocytochemistry for viral specific nucleoprotein and qRT-PCR for viral specific phosphoprotein gene mRNA, were used. Ribavirin at concentrations between 2.5 and 25 ?g/mL inhibited parrot bornavirus 4 replication, decreasing viral mRNA and viral protein load, in infected duck embryonic fibroblast cells. The addition of guanosine diminished the antiviral activity of ribavirin suggesting that one possible mechanism of action against parrot bornavirus 4 may likely be through inosine monophosphate dehydrogenase inhibition. This study demonstrates parrot bornavirus 4 susceptibility to ribavirin in cell culture. PMID:26222794

  10. Inhibition of Insulin-Regulated Aminopeptidase (IRAP) by Arylsulfonamides

    PubMed Central

    Borhade, Sanjay R; Rosenström, Ulrika; Sävmarker, Jonas; Lundbäck, Thomas; Jenmalm-Jensen, Annika; Sigmundsson, Kristmundur; Axelsson, Hanna; Svensson, Fredrik; Konda, Vivek; Sköld, Christian; Larhed, Mats; Hallberg, Mathias

    2014-01-01

    The inhibition of insulin-regulated aminopeptidase (IRAP, EC 3.4.11.3) by angiotenesin IV is known to improve memory and learning in rats. Screening 10 500 low-molecular-weight compounds in an enzyme inhibition assay with IRAP from Chinese Hamster Ovary (CHO) cells provided an arylsulfonamide (N-(3-(1H-tetrazol-5-yl)phenyl)-4-bromo-5-chlorothiophene-2-sulfonamide), comprising a tetrazole in the meta position of the aromatic ring, as a hit. Analogues of this hit were synthesized, and their inhibitory capacities were determined. A small structure–activity relationship study revealed that the sulfonamide function and the tetrazole ring are crucial for IRAP inhibition. The inhibitors exhibited a moderate inhibitory potency with an IC50=1.1±0.5 ?m for the best inhibitor in the series. Further optimization of this new class of IRAP inhibitors is required to make them attractive as research tools and as potential cognitive enhancers. PMID:25558444

  11. Proteasome Inhibition by Fellutamide B Induces Nerve Growth Factor Synthesis

    PubMed Central

    Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M.

    2008-01-01

    SUMMARY Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High resolution structural information obtained from co-crystallization of the 20S proteasome reveals novel aspects regarding ?-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

  12. Proteasome inhibition by fellutamide B induces nerve growth factor synthesis.

    PubMed

    Hines, John; Groll, Michael; Fahnestock, Margaret; Crews, Craig M

    2008-05-01

    Neurotrophic small molecules have the potential to aid in the treatment of neuronal injury and neurodegenerative diseases. The natural product fellutamide B, originally isolated from Penicillium fellutanum, potently induces nerve growth factor (NGF) release from fibroblasts and glial-derived cells, although the mechanism for this neurotrophic activity has not been elucidated. Here, we report that fellutamide B potently inhibits proteasome catalytic activity. High-resolution structural information obtained from cocrystallization of the 20S proteasome reveals novel aspects regarding beta-subunit binding and adduct formation by fellutamide B to inhibit their hydrolytic activity. We demonstrate that fellutamide B and other proteasome inhibitors increased NGF gene transcription via a cis-acting element (or elements) in the promoter. These results demonstrate an unrecognized connection between proteasome inhibition and NGF production, suggesting a possible new strategy in the development of neurotrophic agents. PMID:18482702

  13. Inhibition of methane consumption in forest soils by monoterpenes

    SciTech Connect

    Amaral, J.A.; Knowles, R.

    1998-04-01

    Selected monoterpenes were tested for their ability to inhibit atmospheric methane consumption by three forest soils from different vegetation types and by the cultured methanotrophic strain, Methylosinus trichosporium OB3b. Subsurface soil from coniferous (Pinus banksiana), deciduous (Populus tremuloides), and mixed hardwood (Tsuga canadensis and Prunus pensylvanica) stands was used under field-moist and slurry conditions. Most of the hydrocarbon monoterpenes tested significantly inhibited methane consumption by soils at environmentally relevant levels, with ({minus})-{alpha}-pinene being the most effective. With the exception of {beta}-myrcene, monoterpenes also strongly inhibited methane oxidation by Methylosinus trichosporium OB3b. Carbon dioxide production was stimulated in all of the soils by the monoterpenes tested. In one case, methane production was stimulated by ({minus})-{alpha}-pinene in an intact, aerobic core. Oxide and alcohol monoterpenoids stimulated methane production. Thus, monoterpenes appear to be potentially important regulators of methane consumption and carbon metabolism in forest soils.

  14. Sulfonamide inhibition studies of the ? carbonic anhydrase from Drosophila melanogaster.

    PubMed

    Syrjänen, Leo; Parkkila, Seppo; Scozzafava, Andrea; Supuran, Claudiu T

    2014-07-01

    An inibition study of the ?-carbonic anhydrase (CA, EC 4.2.1.1) DmBCA from the insect Drosophila melanogaster with sulfonamides and sulfamates is reported. Among the panel of 40 investigated compounds, the best DmBCA inhibitors were the sulfonylated benzenesulfonamides and ethoxzolamide, which showed inhibition constants in the range of 65.3-138 nM. Methazolamide and sulthiame were also effective inhibitors with KIs ranging between 237 and 249 nM, whereas most of the simple aromatic/heterocyclic sulfonamides showed inhibition constants in the range of 0.47-6.40 ?M. Topiramate, zonisamide and saccharine did not inhibit DmBCA. As orthologs of this mitochondrial CA are found in many insect species involved in the spread of various diseases, inhibitors interfering with their activity may be of interest for developing insecticides with an alternative mechanism of action to the presently used agents, for which many insects developed extensive resistance. PMID:24852120

  15. D-Glucosamine inhibits proliferation of human cancer cells through inhibition of p70S6K

    SciTech Connect

    Oh, Hyun-Ji; Lee, Jason S.; Song, Dae-Kyu; Shin, Dong-Hoon; Jang, Byeong-Churl; Suh, Seong-Il; Park, Jong-Wook; Suh, Min-Ho; Baek, Won-Ki . E-mail: wonki@dsmc.or.kr

    2007-09-07

    Although D-glucosamine has been reported as an inhibitor of tumor growth both in vivo and in vitro, the mechanism for the anticancer effect of D-glucosamine is still unclear. Since there are several reports suggesting D-glucosamine inhibits protein synthesis, we examined whether D-glucosamine affects p70S6 K activity, an important signaling molecule involved in protein translation. In the present study, we found D-glucosamine inhibited the activity of p70S6K and the proliferation of DU145 prostate cancer cells and MDA-MB-231 breast cancer cells. D-Glucosamine decreased phosphorylation of p70S6K, and its downstream substrates RPS6, and eIF-4B, but not mTOR and 4EBP1 in DU145 cells, suggesting that D-glucosamine induced inhibition of p70S6K is not through the inhibition of mTOR. In addition, D-glucosamine enhanced the growth inhibitory effects of rapamycin, a specific inhibitor of mTOR. These findings suggest that D-glucosamine can inhibit growth of cancer cells through dephosphorylation of p70S6K.

  16. Inhibition of Adipogenesis by Oligonol through Akt-mTOR Inhibition in 3T3-L1 Adipocytes

    PubMed Central

    Park, Jae-Yeo; Kim, Younghwa; Im, Jee Ae; You, Seungkwon

    2014-01-01

    Polyphenols have recently become an important focus of study in obesity research. Oligonol is an oligomerized polyphenol, typically comprised of catechin-type polyphenols from a variety of fruits, which has been found to exhibit better bioavailability and bioreactivity than natural polyphenol compounds. Here, we demonstrated that Oligonol inhibits 3T3-L1 adipocyte differentiation by reducing adipogenic gene expression. During adipogenesis, Oligonol downregulated the mRNA levels of peroxisome proliferator-activated receptor ? (PPAR?), CCAAT/enhancer binding proteins ? (C/EBP?), and ? (C/EBP?) in a dose-dependent manner and the expression of genes involved in lipid biosynthesis. The antiadipogenic effect of Oligonol appears to originate from its ability to inhibit the Akt and mammalian target of rapamycin (mTOR) signaling pathway by diminishing the phosphorylation of ribosomal protein S6 kinase (p70S6K), a downstream target of mTOR and forkhead box protein O1 (Foxo1). These results suggest that Oligonol may be a potent regulator of obesity by repressing major adipogenic genes through inhibition of the Akt signaling pathway, which induces the inhibition of lipid accumulation, ultimately inhibiting adipogenesis. PMID:25295069

  17. Inhibition of virulence potential of Vibrio cholerae by natural compounds

    PubMed Central

    Yamasaki, Shinji; Asakura, Masahiro; Neogi, Sucharit Basu; Hinenoya, Atsushi; Iwaoka, Emiko; Aoki, Shunji

    2011-01-01

    The rise in multi-drug resistant Vibrio cholerae strains is a big problem in treatment of patients suffering from severe cholera. Only a few studies have evaluated the potential of natural compounds against V. cholerae. Extracts from plants like ‘neem’, ‘guazuma’, ‘daio’, apple, hop, green tea and elephant garlic have been shown to inhibit bacterial growth or the secreted cholera toxin (CT). However, inhibiting bacterial growth like common antimicrobial agents may also impose selective pressure facilitating development of resistant strains. A natural compound that can inhibit virulence in V. cholerae is an alternative choice for remedy. Recently, some common spices were examined to check their inhibitory capacity against virulence expression of V. cholerae. Among them methanol extracts of red chili, sweet fennel and white pepper could substantially inhibit CT production. Fractionation of red chili methanol extracts indicated a hydrophobic nature of the inhibitory compound(s), and the n-hexane and 90 per cent methanol fractions could inhibit >90 per cent of CT production. Purification and further fractionation revealed that capsaicin is one of the major components among these red chili fractions. Indeed, capsaicin inhibited the production of CT in various V. cholerae strains regardless of serogroups and biotypes. The quantitative reverse transcription real-time PCR assay revealed that capsaicin dramatically reduced the expression of major virulence-related genes such as ctxA, tcpA and toxT but enhanced the expression of hns gene that transcribes a global prokaryotic gene regulator (H-NS). This indicates that the repression of CT production by capsaicin or red chili might be due to the repression of virulence genes transcription by H-NS. Regular intake of spices like red chili might be a good approach to fight against devastating cholera. PMID:21415500

  18. Kinetics of inhibition of platelet calpain II by human kininogens.

    PubMed Central

    Bradford, H N; Schmaier, A H; Colman, R W

    1990-01-01

    The plasma kininogens, high-molecular-mass and low-molecular-mass kininogens, are the most potent plasma inhibitors of platelet calpain. We explored the kinetic mechanisms for kininogen inhibition of calpain by comparing calpain inactivation by human high-molecular-mass kininogen (HK) and human low-molecular-mass kininogen (LK). With a [14C]methylated alpha-casein substrate, the inhibition of calpain by HK did not follow classic Michaelis-Menten kinetics. With the use of a fluorogenic assay with the dipeptide substrate for calpain, 3-carboxypropionyl-leucyltyrosine 7-(4-methyl)coumarylamide, the inhibition by HK and LK fitted a kinetic model of tight-binding inhibition. LK was found to be a non-competitive inhibitor of platelet calpain with a Ki of 2.7 nM. HK showed mixed non-competitive inhibition of calpain with a Ki of 2.3 nM in the absence of substrate and Ki of 0.71 nM in the presence of saturating substrate, almost 4-fold tighter than LK. Proteolysis of HK by plasma and tissue kallikreins did not influence its ability to inhibit calpain. Digestion of the HK light chain by Factor XIa also did not alter its calpain-inhibitory function. These studies indicate that the kininogens are tight-binding non-competitive inhibitors of platelet calpain, the inhibitory domain in each case being mainly on the heavy chain. The light chain of HK appears to influence its kinetic behaviour. Images Fig. 1. Fig. 2. PMID:2396995

  19. Proton pump inhibition--the ultimate control of acid secretion

    SciTech Connect

    Zdon, M.J.; Ballantyne, G.H.; Schafer, D.E.; Tyshkov, M.; Cambria, R.P.; Modlin, I.M.

    1986-04-01

    The cellular mechanisms of acid secretion by the parietal cell (PC) include stimulation of membrane receptors, increases in cytosolic cyclic AMP levels, and activation of protein kinase systems. These events culminate in stimulation of a membrane-based proton pump. This consists of a non-electrogenic H+-K+-ATPase which transports H+ ions into the secretory canaliculus of the PC in exchange for the cation K+. It has been proposed that blockade of this proton pump would result in inhibition of acid secretion by all classes of acid secretagogues. Thus, the effects of membrane receptor agonists as well as any agents which augment cellular cAMP levels should be inhibited. Substituted benzimidazoles are weak bases which prevent acid secretion by blocking the H+-K+-ATPase system. In order to test the above hypothesis, we investigated the effects of the substituted benzimidazole H168/68 and cimetidine (C) on histamine (H) and 8B-stimulated acid secretion. The rabbit isolated gastric gland (IGG) model was used and acid secretion assessed by the accumulation of /sup 14/C-labeled weak base aminopyrine (AP) within the IGG in response to secretagogue stimulation. H168/68 and C both inhibited H (5 X 10(-5) M)-stimulated (/sup 14/C)AP accumulation in a concentration-dependent manner (P less than 0.05). H168/68 inhibited both H- and 8B-stimulated (/sup 14/C)AP accumulation (P less than 0.05), while C inhibited only H-stimulated (/sup 14/C)AP accumulation (P less than 0.05). H168/68 suppressed (/sup 14/C)AP below even unstimulated levels of (/sup 14/C)AP accumulation. These results support the hypothesis that H168/68 inhibits the PC distal to cAMP stimulation.

  20. SPATIALLY SPECIFIC DEPENDENCE OF SACCADE INHIBITION ON DISTRACTOR REPETITION.

    PubMed

    Shan, Yijing; Edelman, Jay

    2015-09-01

    The sudden appearance of a visual distractor can briefly, but powerfully, inhibits saccades (Reingold and Stampe, 2002). However, this inhibitory influence of distractors may by habituation with repeated distractor presentation at a single retinotopic location, or by a more spatially general dampening of inhibition, occurring when distractors appear at a high frequency at any location in the visual field. Indeed, such a spatially generalized mechanism could be useful during behavior in highly dynamic visual environments. We examined these possibilities by recording the eye movements of 2 subjects in tasks that required the execution of saccades in the face of visual distractors. Eye movements were recorded at 500 Hz (Eyelink II, SR Research). Trials began with central fixation. A 1° square was flashed (250 ms) 10° to the left or right. 700-1000 ms later, fixation point disappearance ("go" signal) cued saccade initiation. Subjects were instructed to make a saccade to the target's remembered location. There were 4 experimental tasks: 1) no distractor; 2) single distractor appearing soon after go signal, opposite the remembered target; 3) 3 distractors at 200 ms intervals at a single location opposite the remembered target; 4) three distractors at 200 ms intervals at three separate locations distant from the remembered target, with the final distractor appearing opposite the remembered target. As in previous experiments (Edelman and Xu, 2009) we found strong inhibition in Task 2. Saccade inhibition was virtually eliminated in Task 3. In Task 4, saccade inhibition was intermediate to that of Tasks 2 and 3. These results suggest that stimulus repetition at a single location strongly ameliorates saccade inhibition, but that a more spatially generalized amelioration mechanism for repeated distractor presentation also exists. Supported by NCRR 2G12RR03060-26A1, NIMHHD 8G12MD007603-27 Meeting abstract presented at VSS 2015. PMID:26326967

  1. Inhibition of virulence potential of Vibrio cholerae by natural compounds.

    PubMed

    Yamasaki, Shinji; Asakura, Masahiro; Neogi, Sucharit Basu; Hinenoya, Atsushi; Iwaoka, Emiko; Aoki, Shunji

    2011-02-01

    The rise in multi-drug resistant Vibrio cholerae strains is a big problem in treatment of patients suffering from severe cholera. Only a few studies have evaluated the potential of natural compounds against V. cholerae. Extracts from plants like 'neem', 'guazuma', 'daio', apple, hop, green tea and elephant garlic have been shown to inhibit bacterial growth or the secreted cholera toxin (CT). However, inhibiting bacterial growth like common antimicrobial agents may also impose selective pressure facilitating development of resistant strains. A natural compound that can inhibit virulence in V. cholerae is an alternative choice for remedy. Recently, some common spices were examined to check their inhibitory capacity against virulence expression of V. cholerae. Among them methanol extracts of red chili, sweet fennel and white pepper could substantially inhibit CT production. Fractionation of red chili methanol extracts indicated a hydrophobic nature of the inhibitory compound(s), and the n-hexane and 90 per cent methanol fractions could inhibit >90 per cent of CT production. Purification and further fractionation revealed that capsaicin is one of the major components among these red chili fractions. Indeed, capsaicin inhibited the production of CT in various V. cholerae strains regardless of serogroups and biotypes. The quantitative reverse transcription real-time PCR assay revealed that capsaicin dramatically reduced the expression of major virulence-related genes such as ctxA, tcpA and toxT but enhanced the expression of hns gene that transcribes a global prokaryotic gene regulator (H-NS). This indicates that the repression of CT production by capsaicin or red chili might be due to the repression of virulence genes transcription by H-NS. Regular intake of spices like red chili might be a good approach to fight against devastating cholera. PMID:21415500

  2. Nesfatin-1 inhibits ovarian epithelial carcinoma cell proliferation in vitro

    SciTech Connect

    Xu, Yang; Pang, Xiaoyan; Dong, Mei; Wen, Fang Zhang, Yi

    2013-11-01

    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 obesity 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.

  3. Equalizing Excitation-Inhibition Ratios across Visual Cortical Neurons

    PubMed Central

    Xue, Mingshan; Atallah, Bassam V; Scanziani, Massimo

    2014-01-01

    The relationship between synaptic excitation and inhibition (E/I ratio), two opposing forces in the mammalian cerebral cortex, affects many cortical functions like feature selectivity and gain1,2. Individual pyramidal cells show stable E/I ratios in time despite fluctuating cortical activity levels because when excitation increases, inhibition increases proportionally through the increased recruitment of inhibitory neurons, a phenomenon referred to as excitation-inhibition balance3–9. However, little is known about the distribution of E/I ratios across pyramidal cells. Through their highly divergent axons inhibitory neurons indiscriminately contact most neighboring pyramidal cells10,11. Is inhibition homogeneously distributed or is it individually matched to the different amounts of excitation received by distinct pyramidal cells? Here we discover that pyramidal cells in layer 2/3 of mouse primary visual cortex (V1) each receive inhibition in a similar proportion to their excitation. As a consequence E/I ratios are equalized across pyramidal cells. This matched inhibition is mediated by parvalbumin-expressing (PV) but not somatostatin-expressing (SOM) inhibitory neurons and results from the independent adjustment of synapses originating from the same PV cell but targeting different pyramidal cells. Furthermore, this match is activity-dependent as it is disrupted by perturbing pyramidal cell activity. Thus, the equalization of E/I ratios across pyramidal cells reveals an unexpected degree of order in the spatial distribution of synaptic strengths and indicates that the relationship between cortex’s two opposing forces is stabilized not only in time but also in space. PMID:25043046

  4. Vanadate-induced inhibition of renin secretion is unrelated to inhibition Na,K-ATPase activity

    SciTech Connect

    Churchill, P.C.; Rossi, N.F.; Churchill, M.C.; Ellis, V.R. )

    1990-01-01

    There is evidence that three inhibitors of Na,K-ATPase activity-ouabain, K-free extracellular fluid, and vanadate--inhibit renin secretion by increasing Ca{sup 2+} concentration in juxtaglomerular cells, but in the case of vanadate, it is uncertain whether the increase in Ca{sup 2+} is due to a decrease in Ca{sup 2+} efflux or to an increase in Ca{sup 2+} influx through potential operated Ca channels. In the present experiments, the rat renal cortical slice preparation was used to compare and contrast the effects of ouabain, of K-free fluid, and of vanadate on renin secretion, in the absence and presence of methoxyverapamil, A Ca channel blocker. Basal renin secretory rate averaged 7.7 {plus minus} 0.3 GU/g/60 min, and secretory rate was reduced to nearly zero by 1 mM ouabain, by K-free fluid, by 0.5 mM vanadate, and by K-depolarization. Although 0.5 {mu}M methoxyverapamil completely blocked the inhibitory effect of K-depolarization, it failed to antagonize the inhibitory effects of ouabain, of K-free fluid, and of vanadate.

  5. Antisense inhibition of hyaluronan synthase-2 in human osteosarcoma cells inhibits hyaluronan retention and tumorigenicity

    SciTech Connect

    Nishida, Yoshihiro . E-mail: ynishida@med.nagoya-u.ac.jp; Knudson, Warren; Knudson, Cheryl B.; Ishiguro, Naoki

    2005-07-01

    Osteosarcoma is a common malignant bone tumor associated with childhood and adolescence. The results of numerous studies have suggested that hyaluronan plays an important role in regulating the aggressive behavior of various types of cancer cells. However, no studies have addressed hyaluronan with respect to osteosarcomas. In this investigation, the mRNA expression copy number of three mammalian hyaluronan synthases (HAS) was determined using competitive RT-PCR in the osteoblastic osteosarcoma cell line, MG-63. MG-63 are highly malignant osteosarcoma cells with an abundant hyaluronan-rich matrix. The results demonstrated that HAS-2 is the predominant HAS in MG-63. Accumulation of intracellular hyaluronan increased in association with the proliferative phase of these cells. The selective inhibition of HAS-2 mRNA in MG-63 cells by antisense phosphorothioate oligonucleotides resulted in reduced hyaluronan accumulation by these cells. As expected, the reduction in hyaluronan disrupted the assembly of cell-associated matrices. However, of most interest, coincident with the reduction in hyaluronan, there was a substantial decrease in cell proliferation, a decrease in cell motility and a decrease in cell invasiveness. These data suggest that hyaluronan synthesized by HAS-2 in MG-63 plays a crucial role in osteosarcoma cell proliferation, motility, and invasion.

  6. Cigarette Smoke Inhibits Engulfment of Apoptotic Cells by Macrophages through Inhibition of Actin Rearrangement

    PubMed Central

    Minematsu, Naoto; Blumental-Perry, Anna; Shapiro, Steven D.

    2011-01-01

    Exposure to cigarette smoke (CS) was shown to impair the capacity of macrophages to clear bacteria and apoptotic cells. Here, we show that both the exposure of macrophages to cigarette smoke extract (CSE) in vitro and an acute single exposure to CS in vivo impair the macrophage clearance of apoptotic polymorphonuclear leukocytes (PMNs). Upon longer periods of exposure to smoke in vivo (4–12 weeks), the impaired capacity of macrophages to clear apoptotic cells persisted after the cessation of smoking, with slow recovery to normality observed 4 weeks later. With respect to the mechanism by which CS impairs the macrophage uptake of apoptotic PMNs, we did not detect altered surface expression of receptors associated with apoptotic cell clearance. We did observe the impaired phosphorylation of the guanine nucleotide exchange factor Vav1 and the downstream inhibition of Ras-related C3 botulinum toxin substrate 1 (Rac1) activation. Consistent with these findings, CS impaired the macrophage cytoskeletal changes observed after stimulation with apoptotic cells. A loss of actin occurred at the leading edge, manifested as impaired ruffling of the cell membrane and a decreased capacity to engulf apoptotic cells. The inability to clear PMNs would lead to a greater release of destructive PMN products, and would diminish the reparative phenotype induced by the macrophage clearance of apoptotic cells. PMID:20525804

  7. Inhibition of brain tumor cell proliferation by alternating electric fields

    SciTech Connect

    Jeong, Hyesun; Oh, Seung-ick; Hong, Sunghoi E-mail: radioyoon@korea.ac.kr; Sung, Jiwon; Jeong, Seonghoon; Yoon, Myonggeun E-mail: radioyoon@korea.ac.kr; Koh, Eui Kwan

    2014-11-17

    This study was designed to investigate the mechanism by which electric fields affect cell function, and to determine the optimal conditions for electric field inhibition of cancer cell proliferation. Low-intensity (<2?V/cm) and intermediate-frequency (100–300 kHz) alternating electric fields were applied to glioblastoma cell lines. These electric fields inhibited cell proliferation by inducing cell cycle arrest and abnormal mitosis due to the malformation of microtubules. These effects were significantly dependent on the intensity and frequency of applied electric fields.

  8. Inhibition of soluble epoxide hydrolase by fulvestrant and sulfoxides

    PubMed Central

    Morisseau, Christophe; Pakhomova, Svitlana; Hwang, Sung Hee; Newcomer, Marcia E; Hammock, Bruce D.

    2013-01-01

    The soluble epoxide hydrolase (sEH) is a key enzyme in the metabolism of epoxy-fatty acids, signaling molecules involved in numerous biologies. Toward finding novel inhibitors of sEH, a library of known drugs was tested for inhibition of sEH. We found that fulvestrant, an anticancer agent, is a potent (KI = 26 nM) competitive inhibitor of sEH. From this observation we found that alkyl-sulfoxides represent a new kind of pharmacophore for the inhibition of sEH. PMID:23684894

  9. Nonlinear group-contribution models of corrosion inhibition

    SciTech Connect

    Lukovits, I.; Kalman, E.; Palinkas, G.

    1995-03-01

    The correlation between the molecular structure and the inhibitor efficiency (E{sub i}) of triamines was investigated. The group-contribution approach was adapted to account for Langmuir- and Frumkin-type inhibition. The group contributions (a{sub j}) were obtained using a nonlinear regression technique. It was assumed that corrosion inhibition was proportional with coverage, which in turn was accounted for by the langmuir and Frumkin models of adsorption. The multiple correlation coefficient obtained by the linear group-contribution model was improved markedly by using adsorption models. On the basis of these results, a more efficient inhibitor molecule was proposed.

  10. Inhibition of methicillin resistant Staphylococcus aureus by a plasma needle

    NASA Astrophysics Data System (ADS)

    Mileti?, Maja; Vukovi?, Dragana; Živanovi?, Irena; Daki?, Ivana; Soldatovi?, Ivan; Maleti?, Dejan; Lazovi?, Saša; Malovi?, Gordana; Petrovi?, Zoran Lj.; Pua?, Nevena

    2014-03-01

    In numerous recent papers plasma chemistry of non equilibrium plasma sources operating at atmospheric pressure has been linked to plasma medical effects including sterilization. In this paper we present a study of the effectiveness of an atmospheric pressure plasma source, known as plasma needle, in inhibition of the growth of biofilm produced by methicillin resistant Staphylococcus aureus (MRSA). Even at the lowest powers the biofilms formed by inoculi of MRSA of 104 and 105 CFU have been strongly affected by plasma and growth in biofilms was inhibited. The eradication of the already formed biofilm was not achieved and it is required to go to more effective sources.

  11. Inhibition of cyclin-dependent kinases by purine analogues.

    PubMed

    Veselý, J; Havlicek, L; Strnad, M; Blow, J J; Donella-Deana, A; Pinna, L; Letham, D S; Kato, J; Detivaud, L; Leclerc, S

    1994-09-01

    While testing purines related to the non-specific protein kinase inhibitors N6-dimethylaminopurine and N6-(delta 2-isopentenyl)adenine as potential inhibitors of the p34cdc2/cyclin B kinase, we discovered a compound with high specificity, 2-(2-hydroxyethylamino)-6- benzylamino-9-methylpurine (olomoucine). Kinetic analysis of kinase inhibition reveals that olomoucine behaves as a competitive inhibitor for ATP and as a non-competitive inhibitor for histone H1 (linear inhibition for both substrates). The kinase specificity of this inhibition was investigated for 35 highly purified kinases (including p34cdk4/cyclin D1, p40cdk6/cyclin D3, cAMP-dependent and cGMP-dependent kinases, eight protein kinase C isoforms, calmodulin-dependent kinase II, myosin light-chain kinase, mitogen-activated S6 kinase, casein kinase 2, double-stranded RNA-activated protein kinase, AMP-stimulated kinase, eight tyrosine kinases). Most kinases are not significantly inhibited. Only the cell-cycle regulating p34cdc2/cyclin B, p33cdk2/cyclin A and p33cdk2/cyclin E kinases, the brain p33cdk5/p35 kinase and the ERK1/MAP-kinase (and its starfish homologue p44mpk) are substantially inhibited by olomoucine (IC50 values are 7, 7, 7, 3 and 25 microM, respectively). The cdk4/cyclin D1 and cdk6/cyclin D3 kinases are not significantly sensitive to olomoucine (IC50 values greater than 1 mM and 150 microM, respectively). N6-(delta 2-Isopentenyl)adenine is confirmed as a general kinase inhibitor with IC50 values of 50-100 microM for many kinases. The purine specificity of cyclin-dependent kinase inhibition was investigated: among 81 purine derivatives tested, only C2, N6 and N9-substituted purines exert a strong inhibitory effect on the p34cdc2/cyclin B kinase. An essentially similar sensitivity to this olomoucine family of compounds was observed for the brain-specific cdk5/p35 kinase. Structure/activity relationship studies allow speculation on the interactions of olomoucine and its analogues with the kinase catalytic subunit. Olomoucine inhibits in vitro M-phase-promoting factor activity in metaphase-arrested Xenopus egg extracts, inhibits in vitro DNA synthesis in Xenopus interphase egg extracts and inhibits the licensing factor, an essential replication factor ensuring that DNA is replicated only once in each cell cycle. Olomoucine inhibits the starfish oocyte G2/M transition in vivo. Through its unique selectivity olomoucine provides an anti-mitotic reagent that may preferentially inhibit certain steps of the cell cycle. PMID:7925396

  12. Enhanced innate immune responses in a brood parasitic cowbird species: Degranulation and oxidative burst

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Design and functionality of the immune system may play a key role in the success of invasive species. We examined the relative effectiveness of functional innate immune defenses in the brown-headed cowbird (Molothrus ater, Icteridae), an invasive avian species that has shown unusual resistance to i...

  13. CTAB-coated gold nanorods elicit allergic response through degranulation and cell death in human basophils

    NASA Astrophysics Data System (ADS)

    Cheung, Ka Lun; Chen, Huanjun; Chen, Qiulan; Wang, Jianfang; Ho, Ho Pui; Wong, Chun Kwok; Kong, Siu Kai

    2012-07-01

    The effect of CTAB (cetyltrimethylammonium bromide)- or PEG (polyethylene glycol)-coated gold-nanorods (Au-NRs) on the non-IgE mediated allergic response was studied. We found that the CTAB-Au-NRs released more allergic mediators such as histamine and ?-hexosaminidase from human basophil KU812, a common model for studying allergy, after 20 min incubation. Also, the CTAB-Au-NRs induced more apoptosis than the PEG-Au-NRs in KU812 24 h after treatment. These short- and long-term effects were not solely due to the CTAB residues in the supernatant desorbed from the Au-NRs.The effect of CTAB (cetyltrimethylammonium bromide)- or PEG (polyethylene glycol)-coated gold-nanorods (Au-NRs) on the non-IgE mediated allergic response was studied. We found that the CTAB-Au-NRs released more allergic mediators such as histamine and ?-hexosaminidase from human basophil KU812, a common model for studying allergy, after 20 min incubation. Also, the CTAB-Au-NRs induced more apoptosis than the PEG-Au-NRs in KU812 24 h after treatment. These short- and long-term effects were not solely due to the CTAB residues in the supernatant desorbed from the Au-NRs. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30435j

  14. UPREGULATION OF OXIDATIVE BURST AND DEGRANULATION IN CHICKEN HETEROPHILIS STIMULATED WITH PROBIOTIC BACTERIA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The immune system of neonatal chicks is functionally immature during the first week of life. Researchers have previously demonstrated that the avian humoral response can be increased through the use of probiotics. Although the humoral response provides the chick with an effective mechanism to comb...

  15. Neural correlates of intentional and stimulus-driven inhibition: a comparison.

    PubMed

    Schel, Margot A; Kühn, Simone; Brass, Marcel; Haggard, Patrick; Ridderinkhof, K Richard; Crone, Eveline A

    2014-01-01

    People can inhibit an action because of an instruction by an external stimulus, or because of their own internal decision. The similarities and differences between these two forms of inhibition are not well understood. Therefore, in the present study the neural correlates of intentional and stimulus-driven inhibition were tested in the same subjects. Participants performed two inhibition tasks while lying in the scanner: the marble task in which they had to choose for themselves between intentionally acting on, or inhibiting a prepotent response to measure intentional inhibition, and the classical stop signal task in which an external signal triggered the inhibition process. Results showed that intentional inhibition decision processes rely on a neural network that has been documented extensively for stimulus-driven inhibition, including bilateral parietal and lateral prefrontal cortex and pre-supplementary motor area. We also found activation in dorsal frontomedian cortex and left inferior frontal gyrus during intentional inhibition that depended on the history of previous choices. Together, these results indicate that intentional inhibition and stimulus-driven inhibition engage a common inhibition network, but intentional inhibition is also characterized by additional context-dependent neural activation in medial prefrontal cortex. PMID:24550808

  16. Inhibition of Antisocial Behavior and Eysenck's Theory of Conscience.

    ERIC Educational Resources Information Center

    Jackson, Nora Mary; Center, David B.

    This report discusses the outcomes of a study that examined a hypothesis about the acquisition of behavioral inhibitions offered by Hans Eysenck, which suggests that what is often described as morality or conscience is acquired through conditioning experiences to which individuals respond differently according to their temperament-based…

  17. Reliability and Plasticity of Response Inhibition and Interference Control

    ERIC Educational Resources Information Center

    Wostmann, Nicola M.; Aichert, Desiree S.; Costa, Anna; Rubia, Katya; Moller, Hans-Jurgen; Ettinger, Ulrich

    2013-01-01

    This study investigated the internal reliability, temporal stability and plasticity of commonly used measures of inhibition-related functions. Stop-signal, go/no-go, antisaccade, Simon, Eriksen flanker, Stroop and Continuous Performance tasks were administered twice to 23 healthy participants over a period of approximately 11 weeks in order to…

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

    SciTech Connect

    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{sup 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.

  19. FOXO1 inhibits osteoclastogenesis partially by antagnozing MYC.

    PubMed

    Tan, Peng; Guan, Hanfeng; Xie, Linka; Mi, Baoguo; Fang, Zhong; Li, Jing; Li, Feng

    2015-01-01

    FOXO transcription factors especially FOXO1 have profound roles in bone development and remodeling. The regulation of cells of the osteoblast lineage by FOXOs is suggested to be stage-specific or context dependent. Intriguingly, recent studies on the role played by FOXOs in osteoclastogenesis reached different conclusion. Bartell et al. showed that FOXOs restrained osteoclastogenesis and bone resorption partially by upregulation of the H2O2-inactivating enzyme catalase. Wang et al. demonstrated that FOXO1 activated osteoclast formation. In the present study, we confirmed the results of Bartell et al. that FOXO1 expression was reduced upon stimulation of RANKL; FOXO1 inhibition promoted and FOXO1 activation repressed, osteoclast differentiation and activity; the inhibitory effect of FOXO1 on osteoclastogenesis was partially mediated by ROS since treatment with ROS scavengers cancelled the effect of FOXO1 inhibition on osteoclastogenesis. We further investigated the mechanisms responsible for repressed osteoclastogenesis by FOXO1. We found that FOXO1 inhibition modulated MAPKs, NF-?B and AP-1. Finally, we proved that the inhibitory effect of FOXO1 on osteoclast formation was partially mediated by MYC suppression by showing that MYC repression almost totally abrogated the effect of FOXO1 inhibition on osteoclastogenesis. To conclude, our study confirmed FOXO1 as a cell-autonomous inhibitor of osteoclastogenesis. PMID:26568463

  20. GSK3? Inhibition Promotes Synaptogenesis in Drosophila and Mammalian Neurons

    PubMed Central

    Enriquez-Barreto, Lilian; Ferrús, Alberto; Morales, Miguel; Acebes, Ángel

    2015-01-01

    The PI3K-dependent activation of AKT results in the inhibition of GSK3? in most signaling pathways. These kinases regulate multiple neuronal processes including the control of synapse number as shown for Drosophila and rodents. Alzheimer disease’s patients exhibit high levels of circulating GSK3? and, consequently, pharmacological strategies based on GSK3? antagonists have been designed. The approach, however, has yielded inconclusive results so far. Here, we carried out a comparative study in Drosophila and rats addressing the role of GSK3? in synaptogenesis. In flies, the genetic inhibition of the shaggy-encoded GSK3? increases the number of synapses, while its upregulation leads to synapse loss. Likewise, in three weeks cultured rat hippocampal neurons, the pharmacological inhibition of GSK3? increases synapse density and Synapsin expression. However, experiments on younger cultures (12 days) yielded an opposite effect, a reduction of synapse density. This unexpected finding seems to unveil an age- and dosage-dependent differential response of mammalian neurons to the stimulation/inhibition of GSK3?, a feature that must be considered in the context of human adult neurogenesis and pharmacological treatments for Alzheimer’s disease based on GSK3? antagonists. PMID:25764078