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Sample records for pokeweed mitogen pwm

  1. The relationship between lymphocytes activated by pokeweed mitogen and by lipopolysaccharides and their radiosensitivity

    International Nuclear Information System (INIS)

    Su Liaoyuan; Liu Fenju; Liu Keliang; Xu Changshao; Xu Yingdong; Geng Yongzhi

    1992-07-01

    Human whole blood was incubated in vitro. Lymphocytes were activated by poke-weed mitogen (PWM) and by Lipopolysaccharides (LPS). The relationship between the two kinds of lymphocytes was investigated using radioactive compound incorporation. The study showed that PWM-activated lymphocytes were able to promote the stimulating effect of LPS on B lymphocytes. The stimulating effect of PWM-activated lymphocytes was obviously decreased after they were irradiated with 10 Gy gamma rays. When PWM-activated lymphocytes and LPS-activated lymphocytes were incubated together after one of the cell populations had been exposed 10 Gy 60 Co gamma rays, the incorporation of [ 3 H] TdR was much decreased and the synergistic function disappeared, especially when the PWM-activated lymphocytes were irradiated. In cells from patients treated with 60 Co gamma rays for carcinoma of nasopharynx, the incorporation in LPS-activated lymphocytes approached normal levels while that in PWM-activated lymphocytes was reduced significantly and the stimulating effect of PWM-activated lymphocytes on LPS-activated lymphocytes was also markedly reduced. These demonstrate that PWM-activated lymphocytes have a similar function to T-helper cells and seem to be more radiosensitive than LPS-activated lymphocytes

  2. Suppression of pokeweed mitogen-stimulated immunoglobulin production in patients with rheumatoid arthritis after treatment with total lymphoid irradiation

    International Nuclear Information System (INIS)

    Kotzin, B.L.; Strober, S.; Kansas, G.S.; Terrell, C.P.; Engleman, E.G.

    1984-01-01

    Patients with intractable rheumatoid arthritis (RA) were treated with total lymphoid irradiation (TLI, 200 rad). The authors previously reported long-lasting clinical improvement in this group associated with a persistent decrease in circulating Leu-3 (helper subset) T cells and marked impairment of in vitro lymphocyte function. In the present experiments, they studied the mechanisms underlying the decrease in pokeweed mitogen stimulated immunoglobulin (Ig) secretion observed after TLI. Peripheral blood mononuclear cells (PBL) from TLI-treated patients produced 10-fold less Ig (both IgM and IgG) in response to pokeweed mitogen than before radiotherapy. This decrease in Ig production was associated with the presence of suppressor cells in co-culture studies. By using responder cells obtained from normal individuals (allogeneic system), PBL from eight of 12 patients after TLI suppressed Ig synthesis by more than 50%. In contrast, PBL from the same patients before TLI failed to suppress Ig synthesis. PBL with suppressive activity contained suppressor T cells, and the latter cells bore the Leu-2 surface antigen. In 50% of the patients studied suppressor cells were also found in the non-T fraction and were adherent to plastic. Interestingly, the Leu-2 + cells from TLI-treated patients were no more potent on a cell per cell basis than purified Leu-2 + cells obtained before TLI. Additional experiments suggested that the suppression mediated by T cells after TLI is related to the increased ratio of Leu-2 to Leu-3 cells observed after radiotherapy

  3. Lymphocyte transformation response to pokeweed mitogen as a predictive marker for development of AIDS and AIDS related symptoms in homosexual men with HIV antibodies

    DEFF Research Database (Denmark)

    Hofmann, B; Lindhardt, B O; Gerstoft, J

    1987-01-01

    To identify factors that may predict the development of the acquired immune deficiency syndrome (AIDS) or AIDS related symptoms various immunological measurements were studied in a group of homosexual men attending screening clinics for AIDS in Copenhagen. Fifty seven men whose ratio of T helper...... the transformation responses to pokeweed mitogen and cytomegalovirus and the absolute count of CD4 positive lymphocytes were the most common abnormal values. In particular, a low relative response to pokeweed mitogen on initial investigation correlated with a worsened clinical condition on reinvestigation. The risk...

  4. HIV-induced immunodeficiency. Relatively preserved phytohemagglutinin as opposed to decreased pokeweed mitogen responses may be due to possibly preserved responses via CD2/phytohemagglutinin pathway

    DEFF Research Database (Denmark)

    Hofmann, B; Jakobsen, K D; Odum, N

    1989-01-01

    We studied the proliferative response of PBL to the mitogens PHA and PWM and Candida albicans Ag in 301 HIV seropositive homosexual men, of whom 55 had AIDS. The responses to PHA were reduced only in the clinically ill HIV seropositive subjects. In contrast, the responses to PWM were profoundly...... and eight controls were chosen for the following studies. Expression of T3, Ti, delta receptors, and CD2 was investigated and showed an increased percentage of CD2 receptors positive cells in HIV seropositive subjects without AIDS. The proliferative responses of PBL to stimulation with PHA, PWM, antibodies...

  5. Normal mitogen-induced suppression of the interleukin-6 (IL-6) response and its deficiency in systemic lupus erythematosus

    International Nuclear Information System (INIS)

    Warrington, R.J.; Rutherford, W.J.

    1990-01-01

    A low-frequency suppressor-cell population in normal peripheral blood inhibits the B-cell CESS response to IL-6, following pokeweed mitogen stimulation. The suppression of IL-6 responsiveness is radiation sensitive, directed against CESS targets and not mediated by inhibition of IL-6 production, and associated with nonspecific cytotoxic activity against CESS targets. The generation of these cytolytic cells is also radiation sensitive. A correlation was found between PWM-induced cytotoxicity against CESS and the suppression of IL-6-dependent IgG production. But cytotoxicity toward CESS targets is not responsible for this suppression because IL-2 induces equivalent or greater nonspecific cytotoxicity against CESS in the total absence of suppression of CESS-derived IgG production and suppression is also induced by mitogen-activated PBL separated from CESS targets by a cell-impermeable membrane. This suppression was not mediated by TNF alpha/beta or IFN-gamma. In systemic lupus erythematosus, suppression of IL-6-dependent IgG production is impaired in patients with active disease (29.2 +/- 13.7%) compared to patients with inactive disease (70 +/- 19.5%) or normal controls (82.8 +/- 9.2%). There is also a defect in mitogen-induced nonspecific cytotoxicity in active SLE (specific lysis 15.1 +/- 3.5%, compared to 34 +/- 4% in normals). Pokeweed mitogen-activated PBL can therefore normally induce suppression of B-cell IL-6 responses and this response is deficient in lupus

  6. Aqueous exposure to Aroclor 1254 modulates the mitogenic response of Atlantic salmon anterior kidney T-cells: Indications of short- and long-term immunomodulation

    Energy Technology Data Exchange (ETDEWEB)

    Iwanowicz, Luke R. [Department of Natural Resources Conservation, University of Massachusetts, Amherst, MA 01003 (United States) and USGS, Leetown Science Center, National Fish Health Research Laboratory, Kearneysville, WV 25430 (United States)]. E-mail: luke_iwanowicz@usgs.gov; Lerner, Darren T. [Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003 (United States); Blazer, Vicki S. [USGS, Leetown Science Center, National Fish Health Research Laboratory, Kearneysville, WV 25430 (United States); McCormick, Stephen D. [Organismic and Evolutionary Biology, University of Massachusetts, Amherst, MA 01003 (United States); USGS, Leetown Science Center, Conte Anadromous Fish Research Center, Turners Falls, MA 01376 (United States)

    2005-05-15

    Polychlorinated biphenyls (PCBs) exist as persistent organic pollutants in numerous river systems in the United States. Unfortunately, some of these rivers are sites of active Atlantic salmon restoration programs, and polychlorinated biphenyls have been implicated as ancillary factors contributing to failed salmon restoration. Here, we investigate the immediate and chronic effects of intermediate duration aqueous PCB exposure (1 or 10 {mu}g L{sup -1} Aroclor 1254) on the mitogen-stimulated lymphoproliferative response of Atlantic salmon anterior kidney leukocytes (AKLs). A short-term study was designed to examine immunomodulation in Atlantic salmon smolts immediately following 21 days of aqueous exposure, while a long-term study evaluated chronic impacts in the mitogen response in parr 15 months post-exposure as larvae. The proliferative response of AKLs to the mitogens concanavalin A (CON A), phytohemaglutinnin-P (PHA-P), pokeweed mitogen (PWM), and lipopolysaccharide were used as an indice of immunomodulation. The proliferative response to the T-cell mitogens CON A and PHA-P was significantly increased in the 10 {mu}g L{sup -1} group (n = 10; P = 0.043 and 0.002, respectively) immediately following exposure of smolts. Additionally, The PHA-P response was significantly increased in the 1 {mu}g L{sup -1} exposure group (n = 10, P = 0.036). In fish treated as larvae and tested 15 months later, the PHA-P sensitive populations exhibited elevated proliferation in the 1 and 10 {mu}g L{sup -1} groups (n = 12, P < 0.04) relative to the vehicle control while the PWM response was significantly increased (n = 12, P 0.036) only in the 10 {mu}g L{sup -1} treated groups. These results demonstrate an immunomodulatory effect of PCBs on T-cell mitogen sensitive populations of lymphocytes in Atlantic salmon as well as long-term immunomodulation in PHA-P and PWM sensitive populations.

  7. Mitogen-induced responses in lymphocytes from platypus, the Tasmanian devil and the eastern barred bandicoot.

    Science.gov (United States)

    Stewart, N J; Bettiol, S S; Kreiss, A; Fox, N; Woods, G M

    2008-10-01

    As the platypus (Ornithorhynchus anatinus), the Tasmanian devil (Sarcophilus harrisi) and the eastern barred bandicoot (Perameles gunni) are currently at risk of serious population decline or extinction from fatal diseases in Tasmania, the goal of the present study was to describe the normal immune response of these species to challenge using the lymphocyte proliferation assay, to give a solid basis for further studies. For this preliminary study, we performed lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) from the three species. We used the common mitogens phytohaemagglutinin (PHA), concanavalin A (ConA), lipopolysaccharide (LPS) and pokeweed mitogen (PWM). All three species recorded the highest stimulation index (SI) with the T-cell mitogens PHA and ConA. Tasmanian devils and bandicoots had greater responses than platypuses, although variability between individual animals was high. For the first time, we report the normal cellular response of the platypus, the Tasmanian devil and the eastern barred bandicoot to a range of commonly used mitogens.

  8. Pokeweed (Phytolacca americana): possible source of a molluscicide

    Science.gov (United States)

    Arnold Krochmal; P.W. LeQuesne; P.W. LeQuesne

    1970-01-01

    Pokeweed, a plant abundant in Appalachia, exhibits some chemical similarities to a related species that has shown molluscicidal properties. Because this suggests that pokeweed, Phytolacca americana L. (P. decandra L.), has potential for controlling fresh-water snails, we have compiled this report of its chenlical composition, uses, propagation methods, and other...

  9. The mitogenic response of cryopreserved human lymphocytes in a microculture system.

    Science.gov (United States)

    Steel, C M; Ennis, M; Levin, A G; Wasunna, A

    1977-01-01

    Fresh blood lymphocytes from nine health donors have been compared with samples from the same donors, recovered after period of 2 to 21 months storage in liquid nitrogen, for the capacity to respond to a range of mitogens in vitro. A microculture assay was used, requireing aliquots of only 25,000 cells. The mean levels of 14C-thymidine uptake for fresh and frozen samples were closely comparable when the cells had been stimulated by PHA, Pokeweed or mitomycin-C-treated allogeneic lymphoblastoid cells. Lymphocytes from six East African donors, frozen by a very simple technique, were recovered after 3 or more years storage in liquid nitrogen. Five of the samples were in good condition as judged by cell viability and the capacity to form spontaneous 'E' rosettes with sheep erythrocytes. These five samples also responded extremely well to PHA, PWM and mitomycin-C-treated allogeneic lymphoblastoid cells using the microculture assay. This study extends the range of applications of cell banks in which small aliquots of blood lymphocytes are stored in liquid nitrogen for periods of several years.

  10. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC patients

    Directory of Open Access Journals (Sweden)

    Bouzouita Kamel

    2004-09-01

    Full Text Available Abstract Background Undifferentiated Nasopharyngeal Carcinoma (NPC patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL and tumor- infiltrating (TIL lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10 and three immunoglobulin isotypes (IgM, IgG, IgA. Methods Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA. Data were analysed using Student's t-test and probability values below 5% were considered significant. Results The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002, IL-10 (p = 0,020, IgM (p= 0,0003 and IgG (p Conclusion Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

  11. Testing of disease-resistance of pokeweed antiviral protein gene ...

    African Journals Online (AJOL)

    Transformation of pokeweed antiviral protein gene (PAP) into plants was shown to improve plant resistance to several viruses or fungi pathogens with no much negative effect on plant growth. The non-virulent defective PAP inhibits only the virus but does not interfere with the host. A non-virulent defective PAP gene ...

  12. The pokeweed leaf mRNA transcriptome and its regulation by jasmonic acid.

    Directory of Open Access Journals (Sweden)

    Kira C.M. Neller

    2016-03-01

    Full Text Available The American pokeweed plant, Phytolacca americana, is recognized for synthesizing pokeweed antiviral protein (PAP, a ribosome inactivating protein (RIP that inhibits the replication of several plant and animal viruses. The plant is also a heavy metal accumulator with applications in soil remediation. However, little is known about pokeweed stress responses, as large-scale sequencing projects have not been performed for this species. Here, we sequenced the mRNA transcriptome of pokeweed in the presence and absence of jasmonic acid (JA, a hormone mediating plant defense. Trinity-based de novo assembly of mRNA from leaf tissue and BLASTx homology searches against public sequence databases resulted in the annotation of 59 096 transcripts. Differential expression analysis identified JA-responsive genes that may be involved in defense against pathogen infection and herbivory. We confirmed the existence of several PAP isoforms and cloned a potentially novel isoform of PAP. Expression analysis indicated that PAP isoforms are differentially responsive to JA, perhaps indicating specialized roles within the plant. Finally, we identified 52 305 natural antisense transcript pairs, four of which comprised PAP isoforms, suggesting a novel form of RIP gene regulation. This transcriptome-wide study of a Phytolaccaceae family member provides a source of new genes that may be involved in stress tolerance in this plant. The sequences generated in our study have been deposited in the SRA database under project # SRP069141.

  13. High power PWM rectifier research report

    International Nuclear Information System (INIS)

    Song Tao; Wang Weiqiang; Chen Duo

    2014-01-01

    This report describes the high power PWM rectifier control principle, hardware and software design technique. By analysis of waveforms and data proves the rectifier meet the application requirements. (authors)

  14. Analisis Harmonisa Inverter PWM Satu Fasa

    OpenAIRE

    Rejeki Simanjorang

    2008-01-01

    Pada tesis ini dianalisis harmonisa inverter PWM satu fasa. Inverter PWM satu fasa yang akan ditinjau adalah inverter satu fasa jembatan penuh (konvensional) dan inverter komposit. Analisis difokuskan pada penentuan pola penyaklaran yang optimum agar pembangkitan harmonisa dan switching losses inverter rendah. Untuk menentukan pola penyaklaran optimum maka dilakukan analisis yang berbasis pada rangkaian ekivalen harmonisa inverter satu fasa. Dengan menggunakan pola penyaklaran optimum, kedua ...

  15. Discrete/PWM Ballast-Resistor Controller

    Science.gov (United States)

    King, Roger J.

    1994-01-01

    Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.

  16. Modified PWM Technique for Harmonic Reduction

    OpenAIRE

    Hoseinpour, Alireza; Ghazi, Reza

    2012-01-01

    This paper presents a Shunt Active Filter (SAF) based on the Variable Index Pulse Width Modulation approach. In the proposed method of Pulse Width Modulation (PWM), the triangular wave is derived by integration of the reference signals. This method introduces two basic advantages; the first one is that the triangular signal contains the information of the signal to be obtained in output and the second advantage is that its amplitude is varied in proportion to the amplitude of the reference si...

  17. Lymphocyte transformation response to pokeweed mitogen as a predictive marker for development of AIDS and AIDS related symptoms in homosexual men with HIV antibodies

    DEFF Research Database (Denmark)

    Hofmann, B; Lindhardt, B O; Gerstoft, J

    1987-01-01

    To identify factors that may predict the development of the acquired immune deficiency syndrome (AIDS) or AIDS related symptoms various immunological measurements were studied in a group of homosexual men attending screening clinics for AIDS in Copenhagen. Fifty seven men whose ratio of T helper...

  18. Comparing seven mitogens with PHA-M for improved lymphocyte stimulation in dicentric chromosome analysis for bio-dosimetry

    International Nuclear Information System (INIS)

    Beinke, C.; Port, M.; Lamkowski, A.; Abend, M.

    2016-01-01

    Dicentric chromosome analysis (DCA) is the gold standard for individual radiation dose estimation. Two limiting factors of DCA are the time-consuming lymphocyte stimulation and proliferation using the lectin PHA-M and the upper dose limit of individual dose assessment of ∼4 Gy. By measuring the mitotic index (MI), the authors investigated systematically whether the stimulation of lymphocytes can be improved after administration of alternative (and combined) mitogens. The authors compared the lymphocyte stimulation effectiveness of the traditionally used PHA-M (from Phaseolus vulgaris) with seven cited mitogens by determination of MIs: five lectins namely CNA (concanavalin A), PW (pokeweed), LMA (Maackia amurensis), LTV (T. vulgaris), PHA-L (P. vulgaris) as well as LPS (lipopolysaccharide, Escherichia coli) and SLO (strepto-lysine O, Streptococcus pyogenes) were applied. The conventional protocol using PHA-M for lymphocyte stimulation proved to be superior over lower/higher PHA-M concentrations as well as seven other mitogens administered either alone or combined with SLO or LPS. (authors)

  19. EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier

    Directory of Open Access Journals (Sweden)

    R. Dolecek

    2008-12-01

    Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.

  20. Noise Shaping Filter Compensating PWM Distortion for Fully Digital Amplifier

    Science.gov (United States)

    Yoneya, Akihiko

    The full-digital audio amplifiers have several merits such as a high power enabling a small size of the amplifier and digital implementation of the signal processing which allows desired precision of the processing except for the final stage switching amplifiers. Unfortunately, the pulse width modulation (PWM) causes signal distortions because of the non-linearity of the modulation from the viewpoint of the transient response. This paper proposes a compensation method of the PWM distortion with feedback approach. In the noise-shaping filter of the delta-sigma modulator to calculate the pulse codes for the PWM, the distortion caused by the PWM is evaluated and fed it back to compensate the distortion. Eventually the filter is implemented as a state-variable filter with non-linear feedback from the quantizer. The calculation of the filter elements is also described. By using proposed filters, PWM signals with small distortions and small floor noise can be obtained to realize high-fidelity audio amplifiers.

  1. Transistorized PWM inverter-induction motor drive system

    Science.gov (United States)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  2. SYNTHESIS OF VOLTAGES OF UNIFORM PWM IN TIME REGULATION

    Directory of Open Access Journals (Sweden)

    A. G. Stryzhniou

    2014-01-01

    Full Text Available The article describes a process of synthesis and qualitative assessment of the harmonic composition of voltages of multiple and single PWM pulses in time regulation, being, along with amplitude, frequency and phase method, one of control methods of an asynchronous motor. The main point of time regulation is that a pause after any two single PWM pulses with different polarity or after any two groups of multiple PWM pulses with different polarity changes during a process of regulation. Feature of time regulation is that a motor has fast response in the range of small-signal of control and good linearity of speed-torque characteristics in the whole control range. Analytical expressions of parameters of PWM pulses ai and ti are obtained which allow to simplify considerably a process of formation and implementation of time regulation using tabular or indexed-tabular methods. These expressions allow not only to define voltage amplitude of  harmonic but also to perform qualitative assessment of harmonic composition of output voltages at time regulation. It is specified that harmonic frequencies wi = w0/q change in inverse proportion to magnitude of parameter q during a process of regulation and there is a replacement of a fundamental frequency by frequencies of higher harmonics.The offered approach allows to synthesize voltage of uniform single and multiple PWM pulses and to perform their comparative and qualitative analysis and the obtained expressions can be used at modeling of AC motor work. Voltage of multiple PWM pulses which is formed using stepped reference voltage with even quantity of steps in a half period and a pause on a zero level has the best parameters by criterion of a minimum of harmonic components and a maximum of a factor of anharmonicity Kнс at time regulation.

  3. A new Zero-Current-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

  4. Simple PWM modulator topology with excellent dynamic behavior

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    This paper proposes a new PWM modulator topology. The modulator is used in switch mode audio power amplifiers, but the topology can be used in a wide range of applications. Due to excellent transient behavior, the modulator is very suited for VRMs or other types of DC-DC or DC-AC applications....

  5. Stator insulation systems for medium voltage PWM drives fed motors

    International Nuclear Information System (INIS)

    Gao, G.; Chen, W.

    2005-01-01

    This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)

  6. A new Zero-Voltage-Transition PWM switching cell

    Energy Technology Data Exchange (ETDEWEB)

    Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics

    1997-12-31

    In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

  7. Control Strategy of PWM Rectifiers Connected to Unbalanced Grids

    Czech Academy of Sciences Publication Activity Database

    Bejvl, Martin; Švec, J.; Tlustý, J.; Valouch, V.

    -, č. 11 (2013) ISSN 2172-038X. [International Conference on Renewable Energies and Power Quality (ICREPQ´13). Bilbao, 20.03.2013-22.03.2013] Institutional support: RVO:61388998 Keywords : electric power system * PWM rectifier * dc voltage ripple Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  8. Boosted PWM open loop control of hydraulic proportional valves

    International Nuclear Information System (INIS)

    Amirante, R.; Innone, A.; Catalano, L.A.

    2008-01-01

    This paper presents an innovative open loop control technique for direct single stage hydraulic proportional valves whose response rate is significantly higher than that obtained by standard open loop control techniques, even comparable to more costly commercial closed loop systems. Different from standard open loop techniques, which provide the coil with a constant current proportional to the target position, the control strategy proposed in this paper employs the peak and hold (P and H) technique, widely used in Diesel engine modern supply systems, to boost the duty cycle value of the pulse width modulation (PWM) signal for a short time, namely during the spool displacement, while maintaining a lower duty cycle for holding the spool in the required opening position. The developed 'boosted PWM' technique only requires a low cost microcontroller, such as a peripheral interface controller (PIC) equipped with a metal oxide semiconductor (MOS) power driver. The PWM parameters are calibrated as a function of the spool displacement so as to maximize the response rate without introducing overshoots: the collected data are stored in the PIC. Different valve opening procedures with step response have been compared to demonstrate the merits of the proposed boosted PWM technique. No overshoots have been registered. Moreover, the proposed method is characterized by a significantly higher response rate with respect to a standard open loop control, which approximately has the same cost. Similar experimental tests show that the proposed boosted PWM technique has a response rate even higher than that provided by the more costly commercial closed loop system mounted on the valve, and it produces no overshoots

  9. A unified triangle carrier based PWM strategy for three-phase N-level diode clamped inverters

    DEFF Research Database (Denmark)

    Li, Kai; Xie, Chuan; Wei, Min

    2017-01-01

    The triangle carrier based pulse width modulation (TCB-PWM) can be functionally equivalent to space vector base PWM (SVB-PWM). For multi-level inverter, it is very difficult to realize the SVB-PWM because its vector space is very complex. In this paper, a unified TCB-PWM strategy for three-phase N......-level diode clamped inverter, including continuous PWM (CPWM) and discontinuous PWM (DPWM), is proposed. With the proposed strategy, the final modulation signals can be easily obtained by twice common mode voltage (CMV) injections. The PWM driver signals are generated by comparing the final modulation signals...... and phase deposition triangle carriers. Especially, the procedures to realize different types of PWM method are demonstrated in this paper. The proposed method can be directly implemented in digital processers....

  10. CNS activity of Pokeweed Anti-viral Protein (PAP in mice infected with Lymphocytic Choriomeningitis Virus (LCMV

    Directory of Open Access Journals (Sweden)

    Tibbles Heather E

    2005-02-01

    Full Text Available Abstract Background Others and we have previously described the potent in vivo and in vitro activity of the broad-spectrum antiviral agent PAP (Pokeweed antiviral protein against a wide range of viruses. The purpose of the present study was to further elucidate the anti-viral spectrum of PAP by examining its effects on the survival of mice challenged with lymphocytic choriomeningitis virus (LCMV. Methods We examined the therapeutic effect of PAP in CBA mice inoculated with intracerebral injections of the WE54 strain of LCMV at a 1000 PFU dose level that is lethal to 100% of mice within 7–9 days. Mice were treated either with vehicle or PAP administered intraperitoneally 24 hours prior to, 1 hour prior to and 24 hours, 48 hours 72 hours and 96 hours after virus inoculation. Results PAP exhibits significant in vivo anti- LCMV activity in mice challenged intracerebrally with an otherwise invariably fatal dose of LCMV. At non-toxic dose levels, PAP significantly prolonged survival in the absence of the majority of disease-associated symptoms. The median survival time of PAP-treated mice was >21 days as opposed to 7 days median survival for the control (p = 0.0069. Conclusion Our results presented herein provide unprecedented experimental evidence that PAP exhibits antiviral activity in the CNS of LCMV-infected mice.

  11. Application of digital PWM technology in current transducers

    International Nuclear Information System (INIS)

    Liu Huifang; Hu Zhimin; Li Rui

    2012-01-01

    With the development of DSP technology and mature use of PID technology,, a new program for DC or AC signal measurement is proposed. Combined with the DSP chip timer module and PID algorithm, PWM signals are generated to control the feedback circuit for the compensation current. Finally the measured current value can be obtained according to the ampere-turns compensation current and the measured current. Studies have shown that this technology enables new current transducers have high stability. (authors)

  12. Power electronic converters PWM strategies and current control techniques

    CERN Document Server

    Monmasson, Eric

    2013-01-01

    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  13. Single-carrier phase-disposition PWM implementation for multilevel flying capacitor converters

    OpenAIRE

    Ghias, Amer M.Y.M; Pou Félix, Josep; Capellá Frau, Gabriel José; Agelidis, Vassilios; Aguilera, Ricardo P; Meynard, Thierry A.

    2015-01-01

    This letter proposes a new implementation of phase-disposition pulse-width modulation (PD-PWM) for multilevel flying capacitor (FC) converters using a single triangular carrier. The proposed implementation is much simpler than conventional PD-PWM techniques based on multiple trapezoidal-shaped carriers, generates the same results as far as natural capacitor voltage balance is concerned and offers better quality line-to-line voltages when compared to phase-shifted PWM. The proposed algorithm i...

  14. Synthesis of Voltages of Multiple Uniform PWM, Generated by Trapezoidal and Sinusoidal Functions

    Directory of Open Access Journals (Sweden)

    A. G. Ctryzhniou

    2013-01-01

    Full Text Available The problem of synthesis and qualitative estimation of the harmonic composition of voltages of multiple uniform PWM pulses generated by trapezoidal and sinusoidal functions is considered. Analytical expressions for PWM pulses parameters ai  and ti have been received and they can be used for program-based generation of multiple uniform PWM, determination of n-harmonic magnitude in pulse-width regulation and AC motor operation simulation.

  15. A New Method to Implement Resampled Uniform PWM Suitable for Distributed Control of Modular Multilevel Converters

    DEFF Research Database (Denmark)

    Huang, Shaojun; Mathe, Laszlo; Teodorescu, Remus

    2013-01-01

    the proper switching instances needed for the resampling modulation technique. The software implementation of the proposed phase shifted PWM (PS-PWM) method, and its application in a distributed control system for MMC, are fully discussed in this paper. Simulation and experiment results show...... that the proposed solution can realize the resampled uniform PWM and provide high effective sampling frequency and low time delay, which is critical for the distributed control of MMC....

  16. High flexibility and low cost digital implementation for modern PWM strategies

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas

    2011-01-01

    In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods...... like AZSPWM, NSPWM, or ACRPWM. By using a conventional PWM unit from a microcontroller, these modern modulation techniques are often difficult, or even impossible, to implement. The proposed method can be used to implement PWM strategies even for those microcontrollers which are not equipped...

  17. Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    This paper presents results of analysis and comparison of novel synchronised schemes of pulsewidth modulation (PWM), applied to three-level voltage source inverters with control algorithms providing elimination of the common-mode voltage. The proposed approach is based on a new strategy of digital...... PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...

  18. Comparative Study of two PWM techniques for Three Phase Shunt Hybrid Active Power Filter to Suppress Line Current Harmonics

    OpenAIRE

    SELVAMUTHUKUMARAN Rajasekar; NATARAJAN Muraly; PERIANAYAGAM Ajay-D-VimalRaj; MAHALINGAM Sudhakaran

    2010-01-01

    This paper investigates the performanceand comparison of two pulse-width-modulation (PWM)techniques by employing direct current control strategyapplied to three phase shunt hybrid active power filter(SHAPF). The objective of SHAPF is to eliminate linecurrent harmonics and to incur reactive powercompensation. The direct current control strategy isimplemented using Standard PWM (S-PWM) and aModified PWM (M-WM), in order to compensatecurrent harmonic and reactive power generated bydifferent load...

  19. CONTROL TECHNIQUES FOR VARIOUS BIPOLAR PWM STRATEGIES OF THREE PHASE FIVE LEVEL CASCADED INVERTER

    Directory of Open Access Journals (Sweden)

    C. R. BALAMURUGAN

    2015-07-01

    Full Text Available This paper presents different types of bipolar Pulse Width Modulation (PWM strategies for the chosen Cascaded MultiLevel Inverter (CMLI. The main purpose of MLI is to use power semiconductor devices of lower voltage ratings to realize high voltage levels at inverter output. Due to their ability to obtain refined output voltage waveforms, reduced Total Harmonic Distortion (THD and reduced EMI problems by reducing the switching dv/dt. In this paper, a three phase CMLI is controlled with Sinusoidal PWM strategy with Phase Disposition PWM (PDPWM, Phase Opposition and Disposition PWM (PODPWM, Alternative Phase Opposition and Disposition PWM (APODPWM, Phase Shift PWM (PSPWM and hybrid modulation strategy and the variation of THD in their outputs are observed by varying the modulation index. Simulations are performed using MATLAB-SIMULINK. It is observed that APODPWM and PSPWM provide output with relatively low distortion. It is also seen that PS, APOD and hybrid PWM are found to perform better since they provide relatively higher fundamental RMS output voltage. From hardware results it is seen that POD PWM provides output with relatively low distortion. It is also observed that PSPWM is found to perform better since it provide relatively higher fundamental RMS output voltage.

  20. Development of a PWM precision spraying controller for unmanned aerial vehicles

    Science.gov (United States)

    This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...

  1. Robust Design of Motor PWM Control using Modeling and Simulation

    Science.gov (United States)

    Zhan, Wei

    A robust design method is developed for Pulse Width Modulation (PWM) motor speed control. A first principle model for DC permanent magnetic motor is used to build a Simulink model for simulation and analysis. Based on the simulation result, the main factors that contributed to the average speed variation are identified using Design of Experiment (DOE). A robust solution is derived to reduce the aver age speed control variation using Response Surface Method (RSM). The robustness of the new design is verified using the simulation model.

  2. Optimized choice of method for determining proliferation response of peripheral lymphocytes to mitogens in low dose irradiation with cyclotron fast neutrons

    International Nuclear Information System (INIS)

    Refka, Z.; Svec, M.; Aganov, P.; Svoboda, V.; Podzimek, F.

    1989-01-01

    Heparinized venous blood sampled from seven donors was irradiated with doses of 0.1; 0.25; 0.5; 1.0; 2.0 and 3.0 Gy of fast neutrons of a mean energy of 7.6 MeV using the U 120 M isochronous cyclotron. A non-irradiated control sample was also prepared. A lymphoblastic transformation test was conducted with both the intact and irradiated samples. The samples were cultivated in the RPMI-1640 medium with and without a mitogen addition, this in five time variants, viz., for 48, 72, 90, 96 and 120 hours. The proliferation was monitored of lymphocytes stimulated with mitogens PHA, CON-A and PWM in dependence on the time of cultivation and on the radiation dose. The dose dependent relative response was also studied of the irradiated lymphocytes. (E.J.). 8 figs., 1 tab., 18 refs

  3. Distortion-Free 1-Bit PWM Coding for Digital Audio Signals

    Directory of Open Access Journals (Sweden)

    John Mourjopoulos

    2007-01-01

    Full Text Available Although uniformly sampled pulse width modulation (UPWM represents a very efficient digital audio coding scheme for digital-to-analog conversion and full-digital amplification, it suffers from strong harmonic distortions, as opposed to benign non-harmonic artifacts present in analog PWM (naturally sampled PWM, NPWM. Complete elimination of these distortions usually requires excessive oversampling of the source PCM audio signal, which results to impractical realizations of digital PWM systems. In this paper, a description of digital PWM distortion generation mechanism is given and a novel principle for their minimization is proposed, based on a process having some similarity to the dithering principle employed in multibit signal quantization. This conditioning signal is termed “jither” and it can be applied either in the PCM amplitude or the PWM time domain. It is shown that the proposed method achieves significant decrement of the harmonic distortions, rendering digital PWM performance equivalent to that of source PCM audio, for mild oversampling (e.g., ×4 resulting to typical PWM clock rates of 90 MHz.

  4. Distortion-Free 1-Bit PWM Coding for Digital Audio Signals

    Directory of Open Access Journals (Sweden)

    Mourjopoulos John

    2007-01-01

    Full Text Available Although uniformly sampled pulse width modulation (UPWM represents a very efficient digital audio coding scheme for digital-to-analog conversion and full-digital amplification, it suffers from strong harmonic distortions, as opposed to benign non-harmonic artifacts present in analog PWM (naturally sampled PWM, NPWM. Complete elimination of these distortions usually requires excessive oversampling of the source PCM audio signal, which results to impractical realizations of digital PWM systems. In this paper, a description of digital PWM distortion generation mechanism is given and a novel principle for their minimization is proposed, based on a process having some similarity to the dithering principle employed in multibit signal quantization. This conditioning signal is termed "jither" and it can be applied either in the PCM amplitude or the PWM time domain. It is shown that the proposed method achieves significant decrement of the harmonic distortions, rendering digital PWM performance equivalent to that of source PCM audio, for mild oversampling (e.g., resulting to typical PWM clock rates of 90 MHz.

  5. Novel Three-Phase Current-Regulated Digital PWM and its Behavioral Analysis

    Science.gov (United States)

    Ohshima, Masaaki; Masada, Eisuke

    With respect to PWM algorithm for a three-phase voltage-source ac/dc power converter various studies have been executed and their results have been published since the analog modulation scheme based on triangular carrier wave was proposed in 1960's. PWM algorithm can be considered the heart of the electronic power conversion. Along with progress and evolution of digital technology gate signals are increasingly requested to be generated directly by digital IC, e.g. MPU, DSP or FPGA/CPLD. The paper analyzes quantitatively the precision of the current controllability of digital PWM taking into account of both the sampling period and the delay time the latter of which is inevitably accompanied by digital procedure. The delay time is pointed out to affect the current error double. In addition the paper derives theoretically the condition for digital PWM to accomplish PPCR (Pulse Polarity Consistency Rule, i.e. the next gate command moves only to the adjacent ones). In so far as the authors know no paper offers the mathematical requirements to execute PPCR taking account of the effect by the delay time with digital PWM. The derived theoretical results are summarized as the digital PWM design criteria for a three-phase PWM converter in order to facilitate practical implementation of the theory, which guarantee the PPCR behavior as well as the quantitative preciseness of the current regulation.

  6. Pengaruh Penambahan PWM (Pulse Width Modulation Pada Generator HHO Tipe Dry Cell

    Directory of Open Access Journals (Sweden)

    Fungky Dyan Pertiwi

    2013-09-01

    Full Text Available Generator HHO memanfaatkan proses elektrolisis air agar mendapatkan gas H2. Namun, pada praktiknya pemakaian arus dari aki yang besar dan temperatur tinggi membuat bejana generator menjadi cepat rusak, sehingga dibutuhkan tambahan rangkaian elektronika PWM pada pengujian generator HHO guna mengatasi permasalahan tersebut. Penelitian menggunakan elektroda plat berjumlah 9 berdimensi 120mm 120mm, tebal 1mm dan dibatasi oleh o-ring dengan diameter 126mm, tebal 3mm. Pengujian dilakukan secara eksperimen dengan 2 kelompok yaitu kelompok control yang mana pengujian tanpa menggunakan PWM serta kelompok uji dimana pengujian menggunakan PWM dengan variasi duty cycle 30%, 50% dan 70%. Pengujian dilakukan hingga temperatur elektrolit 93oC. Hasil uji didapatkan bahwa arus, laju produksi dan efisiensi terbesar didapatkan pada pengujian tanpa PWM yang mencapai 60,6A, 6,033 10-6kg/s dan 25,69%. Namun, pada pengambilan data kedua efisiensi turun menjadi 19,74%. Penambahan PWM pada pengujian berpengaruh pada arus dan temperatur yang stabil meskipun laju produksi dan efisiensi lebih kecil daripada pengujian tanpa PWM. Pengujian dengan PWM pada duty cycle 70% menghasilkan laju produksi dan efisiensi terbesar yang mencapai 1,843 10-6 kg/s dan 15,19%.

  7. Soft-switching PWM full-bridge converters topologies, control, and design

    CERN Document Server

    Ruan, Xinbo

    2014-01-01

    Soft-switching PWM full-bridge converters have been widely used in medium-to-high power dc-dc conversions for topological simplicity, easy control and high efficiency. Early works on soft-switching PWM full-bridge converter by many researchers included various topologies and modulation strategies.  However, these works were scattered, and the relationship among these topologies and modulation strategies had not been revealed. This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and

  8. PWM Inverter control and the application thereof within electric vehicles

    Science.gov (United States)

    Geppert, Steven

    1982-01-01

    An inverter (34) which provides power to an A.C. machine (28) is controlled by a circuit (36) employing PWM control strategy whereby A.C. power is supplied to the machine at a preselectable frequency and preselectable voltage. This is accomplished by the technique of waveform notching in which the shapes of the notches are varied to determine the average energy content of the overall waveform. Through this arrangement, the operational efficiency of the A.C. machine is optimized. The control circuit includes a micro-computer and memory element which receive various parametric inputs and calculate optimized machine control data signals therefrom. The control data is asynchronously loaded into the inverter through an intermediate buffer (38). In its preferred embodiment, the present invention is incorporated within an electric vehicle (10) employing a 144 VDC battery pack (32) and a three-phase induction motor (18).

  9. A digital input class-D audio amplifier with sixth-order PWM

    Science.gov (United States)

    Shumeng, Luo; Dongmei, Li

    2013-11-01

    A digital input class-D audio amplifier with a sixth-order pulse-width modulation (PWM) modulator is presented. This modulator moves the PWM generator into the closed sigma—delta modulator loop. The noise and distortions generated at the PWM generator module are suppressed by the high gain of the forward loop of the sigma—delta modulator. Therefore, at the output of the modulator, a very clean PWM signal is acquired for driving the power stage of the class-D amplifier. A sixth-order modulator is designed to balance the performance and the system clock speed. Fabricated in standard 0.18 μm CMOS technology, this class-D amplifier achieves 110 dB dynamic range, 100 dB signal-to-noise rate, and 0.0056% total harmonic distortion plus noise.

  10. A New Method for Maintaining Constant Dither Amplitude in Low Frequency PWM

    Directory of Open Access Journals (Sweden)

    KANG, H.

    2017-02-01

    Full Text Available Various controls for fluid flow and pressure are now required in related industries, and the pulse width modulation (PWM and dithering techniques have become essential for the proportional control of solenoids. However, there is a fatal drawback when the dither current signals are generated as a by-product of low frequency PWM. That is, the average current and the dither amplitude in low frequency PWM cannot be controlled independently. Therefore, a new method for maintaining constant dither amplitudes is proposed in this paper. Throughout the mathematical analysis, the effect of PWM frequency and duty cycle on the average current and dither amplitude was investigated, and the analysis result was validated by electrical experiments. Based on the mathematical analysis, a new method that properly varies both the duty cycle and the PWM frequency to obtain the desired average current and constant dither amplitude was established and verified. This method requires only the calculations for determining the proper PWM frequency and duty cycle, so it is possible to improve the performance of a proportional solenoid valve without additional devices or cost.

  11. Immunological studies in the acquired immunodeficiency syndrome. II. Active suppression or intrinsic defect--investigated by mixing AIDS cells with HLA-DR identical normal cells

    DEFF Research Database (Denmark)

    Hofmann, B; Ødum, Niels; Jakobsen, B K

    1986-01-01

    The lymphocyte transformation responses to mitogens (phytohaemagglutinin (PHA), concanavalin A (Con A), and pokeweed mitogen (PWM)), allogeneic cells, and the antigen-purified protein derivative (PPD) were studied in six acquired immunodeficiency syndrome (AIDS) patients and in six healthy controls......, each of whom was HLA-DR- and mixed lymphocyte culture (MLC)-identical with one of the AIDS patients. No evidence of suppression was observed when irradiated or non-irradiated AIDS peripheral blood mononuclear cells (PBMC) were added to cultures of HLA-DR-identical PMBC from healthy controls stimulated...... with the strong mitogens PHA and Con A or with allogeneic cells, but suppression may be involved in the decreased responses in cultures stimulated with PWM or PPD. Addition of supernatants from macrocultures of AIDS cells did not suppress responses of control PBMC. Thus, suppression by any lymphocyte subset...

  12. Transistor Clamped Five-Level Inverter using Non-Inverting Double Reference Single Carrier PWM Technique for photovoltaic applications

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Padmanaban, Sanjeevikumar; Fedák, Viliam

    2017-01-01

    supplies or capacitor banks. To design the proposed five level inverter five numbers of power control switches and eight diodes are required. The proposed inverter circuitry is investigated by using Non-Inverting Double Reference Single Carrier PWM (NIDRSC PWM) Technique in terms of harmonics content...

  13. Comparative analysis of third harmonic injection PWM and SPWM control techniques for UPS inverter

    Energy Technology Data Exchange (ETDEWEB)

    Wanjekeche, T.; Nicolae, D.V.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa). Dept. of Electrical Engineering

    2008-07-01

    Pulse width modulation (PWM) techniques for uninterruptible power supply (UPS) applications were investigated. The results of analytical and simulation studies were studied in order to determine the equivalence between sinusoidal PWM and third harmonic PWM control technologies in relation to the high conversion factor (CF) and total harmonic distortion (THD) of UPS applications. The inverter simulation used a 3-phase 3-wire topology with a 3-level voltage source inverter. PI controller compensators were included in each of the voltage and current controllers. A voltage major loop controller was used to ensure sinusoidal output voltage. The capacitor voltage, inductor current, and load current were used as feedback control signals. Fourier transform equations were used to characterize harmonic components for double variable controlled waveforms. Results of the study demonstrated that THD-PWMs reduced the peak size of the envelope of each phase leg voltage and increased the modulation index without causing modulation. 9 refs., 1 tab., 12 figs.

  14. EVALUATION OF VARIOUS UNIPOLAR MULTICARRIER PWM STRATEGIES FOR FIVE LEVEL FLYING CAPACITOR INVERTER

    Directory of Open Access Journals (Sweden)

    B. SHANTHI

    2012-06-01

    Full Text Available This paper presents the comparison of unipolar multicarrier Pulse Width Modulation (PWM techniques for the Flying Capacitor Multi Level Inverter (FCMLI. Due to switch combination redundancies, there are certain degrees of freedom to generate the five level AC output voltage. This paper presents the use of Control Freedom Degree (CFD combination. The effectiveness of the PWM strategies developed using CFD are demonstrated by simulation and experimentation. The results indicate that the multilevel inverter triggered by the developed USHPWM strategy exhibits reduced harmonics. PWM strategies developed are implemented in real time using dSPACE/Real Time Interface (RTI. The simulation and experimental output closely match with each other validating the strategies presented.

  15. Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2004-03-15

    In this report a class of isolated PDM and PWM DC-AC SICAMs is described, which introduce the audio reference only in the output stage. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitor. Isolation from the AC mains is achieved using a high frequency (HF) transformer, receiving the HF voltage pulses from the input 'inverter' stage and transferring them to the output 'rectifier+inverter' stage, which can use either PDM or PWM. The latter stage is then interfaced to the load using an output low-pass filter. Each of the dedicated stages is discussed in detail. Measurements on the master/slave PWM DC-AC SICAM prototype are presented to help benchmarking the performance of this class of SICAMs and identify the advantages and drawbacks. (au)

  16. Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

    Directory of Open Access Journals (Sweden)

    Sreenivasappa Veeranna Bhupasandra

    2010-01-01

    Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

  17. High frequency three-phase PWM grid connected drive using silicon-carbide switches

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Pedersen, Jacob Lykke; Nymand, Morten

    2016-01-01

    This paper presents controller design procedure for a fully silicon-carbide (SiC) based three-phase grid-connected PWM drive. The influence of the feedforward compensation for the presented setup is studied and the transfer function of the system with feedforward is derived and compared with the ......This paper presents controller design procedure for a fully silicon-carbide (SiC) based three-phase grid-connected PWM drive. The influence of the feedforward compensation for the presented setup is studied and the transfer function of the system with feedforward is derived and compared...

  18. Led spectral and power characteristics under hybrid PWM/AM dimming strategy

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2010-01-01

    In order to dim LEDs the pulse width modulation (PWM) or amplitude modulation (AM) dimming scheme is typically used. Previous studies show that these dimming schemes can have opposite effects on diodes peak wavelength shift. An experimental study was conducted to test the behavior of InGaN diodes...... and phosphor-converted white diodes under hybrid PWM/AM modulation. Feed forward control schemes that provide stable peak wavelength position during dimming and the ability to compensate the thermally induced color shifts and the decrease of the luminous flux are investigated....

  19. Parallel implementation of DNA sequences matching algorithms using PWM on GPU architecture.

    Science.gov (United States)

    Sharma, Rahul; Gupta, Nitin; Narang, Vipin; Mittal, Ankush

    2011-01-01

    Positional Weight Matrices (PWMs) are widely used in representation and detection of Transcription Factor Of Binding Sites (TFBSs) on DNA. We implement online PWM search algorithm over parallel architecture. A large PWM data can be processed on Graphic Processing Unit (GPU) systems in parallel which can help in matching sequences at a faster rate. Our method employs extensive usage of highly multithreaded architecture and shared memory of multi-cored GPU. An efficient use of shared memory is required to optimise parallel reduction in CUDA. Our optimised method has a speedup of 230-280x over linear implementation on GPU named GeForce GTX 280.

  20. Soft Switching Full-Bridge PWM DC/DC Converter Using Secondary Snubber

    Directory of Open Access Journals (Sweden)

    Jaroslav Dudrik

    2009-05-01

    Full Text Available A novel full-bridge PWM DC/DCconverter with controlled secondary side rectifier usingsecondary snubber is presented in this paper.Limitation of the circulating current as well as softswitching for all power switches of the inverter isachieved for full load range from no-load to shortcircuit by using controlled rectifier and snubber on thesecondary side. Phase shift PWM control strategy isused for the converter. The principle of operation isexplained and analyzed and the experimental resultson a 1kW, 50 kHz laboratory model of the converterare presented.

  1. Mitogenic stimulation of peripheral lymphocytes of thorium workers

    International Nuclear Information System (INIS)

    Serio, C.S.; Henning, C.B.; Lloyd, E.L.

    1979-01-01

    Mitogenic stimulation of lymphocyte cultures from 30 thorium workers was studied to determine whether their immunocompetence was affected by their occupational exposure to radiation. A decrease in lymphocyte responsiveness was seen in these workers when compared with age-matched normal control subjects. The mean decrease relative to the normal controls for three different mitogens tested was 26% with phytohemagglutinin, 40% with concanavalin A, and 30% with poke week mitogen

  2. Electromagnetic phenomena analysis in brushless DC motor with speed control using PWM method

    Science.gov (United States)

    Ciurys, Marek Pawel

    2017-12-01

    Field-circuit model of a brushless DC motor with speed control using PWM method was developed. Waveforms of electrical and mechanical quantities of the designed motor with a high pressure vane pump built in a rotor of the motor were computed. Analysis of electromagnetic phenomena in the system: single phase AC network - converter - BLDC motor was carried out.

  3. Electromagnetic phenomena analysis in brushless DC motor with speed control using PWM method

    Directory of Open Access Journals (Sweden)

    Ciurys Marek Pawel

    2017-12-01

    Full Text Available Field-circuit model of a brushless DC motor with speed control using PWM method was developed. Waveforms of electrical and mechanical quantities of the designed motor with a high pressure vane pump built in a rotor of the motor were computed. Analysis of electromagnetic phenomena in the system: single phase AC network – converter - BLDC motor was carried out.

  4. Performance analysis of SHE-PWM using Fourier Series and Newton-Raphson analysis

    Science.gov (United States)

    Lada, M. Y.; Khiar, M. S. A.; Ghani, S. A.; Nawawi, M. R. M.; Nor, A. S. M.; Yuen, J. G. M.

    2015-05-01

    The performance of inverter has become a vital role in contributing effective power system nowadays. However the major issue that will reduce the inverter performance is the harmonic distortions that contribute to power losses. Thus, there are a variety of controls techniques have been implemented for inverters switching such as square wave, SHE-PWM, unipolar and bipolar. The square wave type inverter produces output voltage in square shape which has simple logic control and power switches. Next, unipolar and bipolar techniques are using comparator to compare the reference voltage waveform with the triangular waveform. The difference between unipolar and bipolar is there are two reference signals which are compared with the triangular waveform for unipolar switching. On the other hand, bipolar switching compares triangular waveform with a reference signal. Selective Harmonic Elimination Pulse-Width Modulation (SHE-PWM) is another control technique for inverters. This research propose SHE-PWM as a low switching frequency strategy that uses Fourier Series and Newton-Raphson analysis to calculate the switching angles for elimination of harmonic distortion. Fourier Series is used to determine the amplitude of any odd harmonic in the output signal whereas Newton-Raphson is used to solve the equation for finding switching angles. As a result, SHE-PWM can select the low frequency harmonic components need to be eliminated and reduce the harmonic distortion. It also prevents the harmonic distortion that sensitive to the inverter performance

  5. Parallel Interleaved VSCs: Influence of the PWM Scheme on the Design of the Coupled Inductor

    DEFF Research Database (Denmark)

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Maheshwari, Ram Krishan

    2014-01-01

    . To limit the circulating current, magnetic coupling between the interleaved legs of the corresponding phase is provided by means of a Coupled Inductor (CI). The design of the CI is strongly influenced by the Pulsewidth Modulation (PWM) scheme used. The analytical model to evaluate the flux...

  6. New PWM method and commutation strategy for HF-link converters for fuel cells and photovoltaics

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a new PWM method and commutation strategy for HF-link converters, which leads to safe commutation of the load current in the output bidirectional bridge. The proposed implementation is independent of the particular HF-link converter topology and bidirectional switch selection ...

  7. The efficiency of three-level Active NPC converter for different PWM strategies

    DEFF Research Database (Denmark)

    Floricau, D.; Gateau, G.; Leredde, A.

    2009-01-01

    The efficiency of power conversion is an important factor to design static converters. The paper is focused on the calculus of total losses of 3L-NPC and 3L-Active-NPC converters for different PWM strategies. The calculus was made in the most critical operating points when certain switches have...

  8. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provides...

  9. An Analytical Modelling of Three-Phase Four-Switch PWM Rectifier Under Unbalanced Supply Conditions

    Czech Academy of Sciences Publication Activity Database

    Klíma, J.; Škramlík, Jiří; Valouch, Viktor

    2007-01-01

    Roč. 54, č. 12 (2007), s. 1155-1159 ISSN 1549-7747 R&D Projects: GA AV ČR IAA200760703 Institutional research plan: CEZ:AV0Z20570509 Keywords : modelling * pulsewidth modulation (PWM) * reactive power Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.104, year: 2007

  10. Analytical closed-form solution of three-phase four-switch PWM rectifier

    Czech Academy of Sciences Publication Activity Database

    Škramlík, Jiří; Valouch, Viktor; Klíma, J.; Pecha, I.

    2010-01-01

    Roč. 55, č. 3 (2010), s. 223-235 ISSN 0001-7043 R&D Projects: GA MPO FT-TA5/123 Institutional research plan: CEZ:AV0Z20570509 Keywords : four-switch PWM rectifier * space vector modulation * closed-form analytical solution Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  11. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Energy Technology Data Exchange (ETDEWEB)

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics

    1997-12-31

    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  12. Apparatus and method for heat-run test on high-power PWM ...

    Indian Academy of Sciences (India)

    ilar or higher rating), both connected in parallel on the ac side and open on the dc side. .... In a PWM converter, there are losses in both IGBT and its anti-parallel diode due to conduction as well as switching ..... Chen T P 2009 Dual-modulator compensation technique for parallel inverters using space-vector modula- tion.

  13. Prognostic value of immunologic abnormalities and HIV antigenemia in asymptomatic HIV-infected individuals: proposal of immunologic staging

    DEFF Research Database (Denmark)

    Hofmann, B; Bygbjerg, Ib Christian; Dickmeiss, E

    1989-01-01

    The prognostic value of various immunologic tests was investigated in 150 HIV-seropositive homosexual men, who were initially without HIV-related symptoms or AIDS and who were followed for a median of 12 months (range 3-28 months). The laboratory investigations included HIV antigen in serum, total...... lymphocyte count, T-helper (CD4) and T-cytotoxic/suppressor (CD8) counts, and lymphocyte transformation responses to the mitogens phytohemagglutinin (PHA) and pokeweed mitogen (PWM), and to antigenic extracts from Candida albicans and cytomegalovirus. 24 individuals developed HIV-related symptoms or AIDS (11...... cases). All parameters except the CD8 count were of prognostic value, but a multivariate analysis of symptom-free survival showed that HIV antigenemia, a CD4 count less than 0.5 x 10(9)/l, and relative response to PWM below 25% of controls contained all the prognostic information. Individuals abnormal...

  14. A new power supply regulated PWM-ZCS supplied in current: analysis, project and experiments; Uma nova fonte chaveada PWM-ZCS alimentada em corrente: analise, projeto e experimentacao

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Peter Mantovanelli

    1993-10-01

    This work introduces a new power supply by PWM, operating at constant frequency, with soft communication. The new topology uses only two active switches and absorbs the transformer leakage inductance. Besides, the soft communication takes place with no conduction loss penalty, in comparison with conventional hard switch PWM converters. Principle of operation, analysis, design and experimentation results taken from laboratory prototype rated at 400 W/48 v, 40 Khz, using IGBT are presented. (author) 10 refs., 71 figs.

  15. The harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter.

    OpenAIRE

    ПАНЧЕНКО, В В

    2015-01-01

    The author investigates a rectifier unit constructed on the basis of cascade connection of the main non-controlled m-pulse rectifier and PWM voltage booster converter. The research presents the analysis of the harmonic composition of the output voltage of a rectifier unit with a PWM voltage booster converter on completely controlled keys. The dependence of the relative harmonic amplitude on the commutation corner is defined. The estimation of a rectifier unit electromagnetic compatibility wit...

  16. The PWM strategies of grid-connected distributed generation active NPC inverters

    DEFF Research Database (Denmark)

    Ma, Lin; Xinmin, Jin; Kerekes, Tamas

    2009-01-01

    The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which...... leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy......, namely the Adjustable Losses Distribution (ALD) PWM strategy is proposed for better losses distribution in the Active NPC (ANPC) topology. Simulations using Simulink and the PLECS toolbox have been done for evaluating efficiency of different NPC topologies and some experimental results are presented...

  17. Shunt PWM advanced var compensators based on voltage source inverters for Facts applications

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Pedro G.; Misaka, Isamu; Watanabe, Edson H. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia

    1994-12-31

    Increased attention has been given to improving power system operation. This paper presents modeling, analysis and design of reactive shunt power compensators based on PWM-Voltage Source Inverters (Pulse Width Modulation -Voltage Source Inverters). (Pulse Width Modulation - Voltage Source Inverters). The control algorithm is based on new concepts of instantaneous active and reactive power theory. The objective is to show that with a small capacitor in the side of a 3-phase PWM-VSI it is possible to synthesize a variable reactive (capacitive or inductive) device. Design procedures and experimental results are presented. The feasibility of this method was verified by digital simulations and measurements on a small scale model. (author) 9 refs., 12 figs.

  18. Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms

    DEFF Research Database (Denmark)

    Oleschuk, V.; Blaabjerg, Frede

    2004-01-01

    synchronous PWM at higher values of the fundamental frequency has also been described. Results of analysis of the spectral characteristics of the output voltage of the inverter show advantage of synchronous PWM in comparison with conventional asynchronous modulation at low indices of the frequency ratio...... their position inside clock-intervals. In order to provide smooth shock-less pulse-ratio changing and quarter-wave symmetry of the voltage waveforms, special synchronising signals are formed on the boundaries of the 60 clock-intervals. The process of gradual transition from continuous to discontinuous...... between the switching and the fundamental frequency. Special attention has been given to the analysis and comparison of the computational effectiveness of the proposed algorithms of synchronized modulation. 0...

  19. Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive

    Directory of Open Access Journals (Sweden)

    Mohanty Kant Nalin

    2010-01-01

    Full Text Available This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI, less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using MATLAB SIMULINK and in the experimental work a prototype model is built to verify the simulation results. PIC microcontroller (PIC 16F877A is used to generate the PWM pulses for FSTPI to drive the 0.5 hp 3-phase Induction Motor.

  20. Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter

    Science.gov (United States)

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes nongrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was small, the phenomenon that polarity of the common mode voltage and shaft voltage reversed was observed. In order to model this phenomenon, the bridge type equivalent circuit is proposed. It is verified with the calculation and experiment that shaft voltage values and polarity are accurately calculated with the proposed equivalent circuit.

  1. Six-Phase Vehicular Drive with Renewable DC Sources and Hybrid PWM Control of Four Inverters

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Ermuratskii, Vladimir; Blaabjerg, Frede

    2015-01-01

    The paper presents results of research of quad-inverter-based automotive system with combined scheme of PWM control of inverters, supplied by two renewable dc sources (by fuel cells and by battery). It has been shown, that hybrid switching techniques can be used successfully for control of vehicle...... drive with non-equal (variable) voltages of dc-links. Results of modeling proved the fact of symmetries of waveforms of the phase voltages of the system for any operating conditions....

  2. PERFORMANCE EVALUATION OF THREE PHASE SCALAR CONTROLLED PWM RECTIFIER USING DIFFERENT CARRIER AND MODULATING SIGNAL

    OpenAIRE

    J. CHELLADURAI; B. VINOD

    2015-01-01

    Power quality problems caused by significant increase of non-linear loads initiated intensive research in high power factor converters. Most of the modern power electronic systems like variable speed drives, DC power supplies and battery charging systems uses uncontrolled diode bridge rectifier. The uncontrolled rectifier system injects lot of harmonics in to the AC supply system there by reducing the power factor to less than unity. Single stage PWM rectifier is the novel solution to elim...

  3. Method of a single phase PWM for a utility-connected power supply in photovoltaic power generation systems; Keito renkeigata taiyoko hatsuden system no tanso PWM no ichihoshiki

    Energy Technology Data Exchange (ETDEWEB)

    Nakae, T. [Kanazawa Technical College, Ishikawa (Japan); Kanamaru, Y.; Amemiya, Y. [Kanazawa Institute of Technology, Ishikawa (Japan)

    1998-09-01

    A method for PWM control of inverter circuits in photovoltaic power generation systems is developed to connect them to utility power supply systems for residences. For controlling sine-wave PWM inverters, it is possible to control a basic wave voltage for inverter output in a range from 0 to 100% by the on-off actions of the switching device, after comparing heights of the carrier wave (triangular wave) and signal wave (sine wave) with each other, to change the signal wave amplitude. The authors has proposed a new method in which the carrier wave is swung over the positive and negative regions corresponding to the positive and negative signal wave, and the on-off phase of the switching device is deviated a little from the phase determined by comparing heights of the carrier and signal waves with each other. Basic wave voltage for inverter output can be increased by about 18%, e.g., at a modulation degree of 80%, from the level obtained by the conventional method. In other words, it is possible to reduce photovoltaic cell array voltage by 15% (i.e., 1/1.18 = 0.85 times) to obtain the same voltage as given by the conventional method. Number of cell modules can be reduced by that, accordingly. The effect of the harmonic component is found to be small. 7 refs., 9 figs., 3 tabs.

  4. PERFORMANCE EVALUATION OF THREE PHASE SCALAR CONTROLLED PWM RECTIFIER USING DIFFERENT CARRIER AND MODULATING SIGNAL

    Directory of Open Access Journals (Sweden)

    J. CHELLADURAI

    2015-04-01

    Full Text Available Power quality problems caused by significant increase of non-linear loads initiated intensive research in high power factor converters. Most of the modern power electronic systems like variable speed drives, DC power supplies and battery charging systems uses uncontrolled diode bridge rectifier. The uncontrolled rectifier system injects lot of harmonics in to the AC supply system there by reducing the power factor to less than unity. Single stage PWM rectifier is the novel solution to eliminate the harmonics and to improve the input power factor. In this paper, a scalar controlled PWM rectifier is modeled and the system is compared with the conventional bridge rectifier with and without filter.The major advantages of using this technique are less intensive computational control and sensor less input voltage operation. The PWM rectifier system is investigated using the different carrier and modulating signal. The scalar control technique is used to control the boost rectifier output voltage and input power factor. The performance of the rectifier with different carrier and modulating techniques were compared with respect to the Total Harmonic Distortion (THD in source current. Simulation results demonstrate the effectiveness of the modified modulating signal and triangular carrier signal for effectively reducing the source current THD.

  5. Converter-flux-based current control of voltage source PWM rectifiers - analysis and implementation

    Energy Technology Data Exchange (ETDEWEB)

    Poellaenen, R.

    2003-07-01

    Pulsewidth-modulated (PWM) rectifier technology is increasingly used in industrial applications like variable-speed motor drives, since it offers several desired features such as sinusoidal input currents, controllable power factor, bidirectional power flow and high quality DC output voltage. To achieve these features, however, an effective control system with fast and accurate current and DC voltage responses is required. From various control strategies proposed to meet these control objectives, in most cases the commonly known principle of the synchronous-frame current vector control along with some space-vector PWM scheme have been applied. Recently, however, new control approaches analogous to the well-established direct torque control (DTC) method for electrical machines have also emerged to implement a high-performance PWM rectifier. In this thesis the concepts of classical synchronous-frame current control and DTC-based PWM rectifier control are combined and a new converter-flux-based current control (CFCC) scheme is introduced. To achieve sufficient dynamic performance and to ensure a stable operation, the proposed control system is thoroughly analysed and simple rules for the controller design are suggested. Special attention is paid to the estimation of the converter flux, which is the key element of converter-flux-based control. Discrete-time implementation is also discussed. Line-voltage-sensorless reactive reactive power control methods for the L- and LCL-type line filters are presented. For the L-filter an open-loop control law for the d-axis current reference is proposed. In the case of the LCL-filter the combined open-loop control and feedback control is proposed. The influence of the erroneous filter parameter estimates on the accuracy of the developed control schemes is also discussed. A new zero vector selection rule for suppressing the zero-sequence current in parallel-connected PWM rectifiers is proposed. With this method a truly standalone and

  6. Research on Single-Phase PWM Converter with Reverse Conducting IGBT Based on Loss Threshold Desaturation Control

    Directory of Open Access Journals (Sweden)

    Xianjin Huang

    2017-11-01

    Full Text Available In the application of vehicle power supply and distributed power generation, there are strict requirements for the pulse width modulation (PWM converter regarding power density and reliability. When compared with the conventional insulated gate bipolar transistor (IGBT module, the Reverse Conducting-Insulated Gate Bipolar Transistor (RC-IGBT with the same package has a lower thermal resistance and higher current tolerance. By applying the gate desaturation control, the reverse recovery loss of the RC-IGBT diode may be reduced. In this paper, a loss threshold desaturation control method is studied to improve the output characteristics of the single-phase PWM converter with a low switching frequency. The gate desaturation control characteristics of the RC-IGBT’s diode are studied. A proper current limit is set to avoid the ineffective infliction of the desaturation pulse, while the bridge arm current crosses zero. The expectation of optimized loss decrease is obtained, and the better performance for the RC-IGBTs of the single-phase PWM converter is achieved through the optimized desaturation pulse distribution. Finally, the improved predictive current control algorithm that is applied to the PWM converter with RC-IGBTs is simulated, and is operated and tested on the scaled reduced power platform. The results prove that the gate desaturation control with the improved predictive current algorithm may effectively improve the RC-IGBT’s characteristics, and realize the stable output of the PWM converter.

  7. Postoperative radiation therapy and adjuvant chemoimmunotherapy in breast cancer. Aspects of timing and immune competence

    Energy Technology Data Exchange (ETDEWEB)

    Klefstroem, P.; Nuortio, L.; Taskinen, E.

    The effects of radiation therapy and adjuvant chemoimmunotherapy on the immune competence of patients with breast cancer were investigated. The tests performed included intradermal tuberculin tests, T- and B-lymphocyte counts, and lymphocyte blast transformation tests; phytohemagglutinin (PHA), concanavalin A (ConA) and pokeweed mitogen (PMW) were used as mitogens. Enhancement in lymphocyte proliferative response to mitogenic stimulation by PHA and PMW was seen in patients after 3 courses of chemotherapy + levamisole, whereas irradiation given after chemotherapy caused long-lasting depression in response to PHA and PWM (not significant). T-lymphocyte counts were also lower after irradiation than after chemoimmunotherapy. Clinically, the 16 patients treated with radiation therapy after chemotherapy exhibited a higher recurrence rate than the 24 patients treated first by irradiation. Enhanced reactivity to tuberculin tests occurred generally in patients receiving a planned treatment including irradiation, chemotherapy (5-fluorouracil, doxorubicin, cyclophosphamide) and levamisole. Enhancement of reactivity was seen more often in patients who had not relapsed.

  8. 交流電動機の極座標空間ベクトル制御に適した新方式電圧形 PWM インバータ

    OpenAIRE

    松本, 久男; 高見, 弘; 清水, 良規; 池田, 隆

    1986-01-01

    This paper presents a new PWM voltage source inverter and an example of its applications. In this PWM inverter, the magnitude and frequency of the motor voltage are separately controlled. This inverter has the following special merits. 1) The arbitrary voltage space vector can be obtained in real time. 2) Compared with the conventional PWM method which synthesize the PWM pattern by comparing a sinusoidal reference signal with a triangular carrier, switching frequency of the switching elements...

  9. Lymphocyte mitogen-induced proliferation in patients with allergic rhinitis

    International Nuclear Information System (INIS)

    Chorostowska-Wynimko, J.; Kleniewska, D.; Sokolnicka, I.; Rogala, E.; Skopinska-Rozewska, E.

    1995-01-01

    Lymphocytes play a central regulatory role in mechanisms contributing to impaired function of immune system in atopy. The aim of our study was evaluate the mitogen-induced proliferation of lymphocytes in a group of asymptomatic, seasonal allergic rhinitis patients. A highly significant lower mitogen-induced proliferation and, in contrast to other studies, significantly lower background proliferative activity of lymphocytes were found in the atopic persons, comparing to the controls. We concluded that the decreased mitogen-induced proliferation of lymphocytes observed in allergic patients reflects abnormal T cell function, which is due to the atopic status, and not only as it was believed to the antigen-induced lymphocyte activation. (author). 26 refs, 1 tab

  10. Lymphocyte mitogen-induced proliferation in patients with allergic rhinitis

    Energy Technology Data Exchange (ETDEWEB)

    Chorostowska-Wynimko, J.; Kleniewska, D.; Sokolnicka, I.; Rogala, E.; Skopinska-Rozewska, E. [Dept. of Immunology. Institute of Tuberculosis and Lung Diseases, Warsaw (Poland)

    1995-12-31

    Lymphocytes play a central regulatory role in mechanisms contributing to impaired function of immune system in atopy. The aim of our study was evaluate the mitogen-induced proliferation of lymphocytes in a group of asymptomatic, seasonal allergic rhinitis patients. A highly significant lower mitogen-induced proliferation and, in contrast to other studies, significantly lower background proliferative activity of lymphocytes were found in the atopic persons, comparing to the controls. We concluded that the decreased mitogen-induced proliferation of lymphocytes observed in allergic patients reflects abnormal T cell function, which is due to the atopic status, and not only as it was believed to the antigen-induced lymphocyte activation. (author). 26 refs, 1 tab.

  11. The optimized PWM driving for the lighting system based on physiological characteristic of human vision

    Science.gov (United States)

    Wang, Ping-Chieh; Uang, Chii-Maw; Hong, Yi-Jian; Ho, Zu-Sheng

    2011-10-01

    Saving energy, White-light LED plays a main role in solid state lighting system. Find the best energy saving driven solution is the engineer endless hard work. Besides DC and AC driving, LED using Pulse Width Modulation (PWM) operation is also a valuable research topic. The most important issue for this work is to find the drive frequency and duty for achieving both energy saving and better feeling on the human vision sensation. In this paper, psychophysics of human vision response to the lighting effect, including Persistence of vision, Bloch's Law, Broca-Sulzer Law, Ferry-Porter Law, Talbot-Plateau Law, and Contrast Sensitivity, will be discussed and analyzed. From the human vision system, we found that there are three factors: the flash sensitivity, the illumination intensity and the background environment illumination, that are used to decide the frequency and duty of the PWM driving method. A set of controllable LED lamps with adjustable frequency and duty is fitted inside a non-closed box is constructed for this experiment. When the background environment illumination intensity is high, the variation of the flash sensitivity and illumination intensity is not easy to observe. Increasing PWM frequency will eliminate flash sensitivity. When the duty is over 70%, the vision sensitivity is saturated. For warning purpose, the better frequency range is between 7Hz to 15Hz and the duty cycle can be lower down to 70%. For general lighting, the better frequency range is between 200Hz to 1000Hz and the duty cycle can also be lower down to 70%.

  12. Design of a High Performance Green-Mode PWM Controller IC with Smart Sensing Protection Circuits

    Directory of Open Access Journals (Sweden)

    Shen-Li Chen

    2014-08-01

    Full Text Available A design of high performance green-mode pulse-width-modulation (PWM controller IC with smart sensing protection circuits for the application of lithium-ion battery charger (1.52 V ~ 7.5 V is investigated in this paper. The protection circuits architecture of this system mainly bases on the lithium battery function and does for the system design standard of control circuit. In this work, the PWM controller will be with an automatic load sensing and judges the system operated in the operating mode or in the standby mode. Therefore, it reduces system’s power dissipation effectively and achieves the saving power target. In the same time, many protection sensing circuits such as: (1 over current protection (OCP and under current protection (UCP, (2 over voltage protection (OVP and under voltage protection (UVP, (3 loading determintion and short circuit protection (SCP, (4 over temperature protection (OTP, (5 VDD surge-spiking protection are included. Then, it has the characteristics of an effective monitoring the output loading and the harm prevention as a battery charging. Eventually, this green-mode pulse-width-modulation (PWM controller IC will be that the operation voltage is 3.3 V, the operation frequency is 0.98 MHz, and the output current range is from 454 mA to 500 mA. Meanwhile, the output convert efficiency is range from 74.8 % to 91 %, the power dissipation efficiency in green-mode is 25 %, and the operation temperature range is between -20 0C ~ 114 0C.

  13. A generalized discontinuous PWM based neutral point voltage balancing method for three-level NPC voltage source inverter with switching losses reduction

    DEFF Research Database (Denmark)

    Li, Kai; Wei, Min; Xie, Chuan

    2017-01-01

    In order to control the neutral point voltage of inverter with discontinuous PWM (DPWM), this paper proposed a generalized discontinuous PWM (GDPWM) based neutral point voltage balancing method for three level neutral point clamped (NPC) voltage source inverter (VSI). Firstly, a triangle carrier ...

  14. Windowed SHE-PWM of Interleaved Four-Quadrant Converters for Resonance Suppression in Traction Power Supply Systems

    DEFF Research Database (Denmark)

    Song, Kejian; Konstantinou, Georgios; Mingli, Wu

    2017-01-01

    AC electric locomotives that use a number of interleaved four-quadrant converters generate high-frequency switching harmonics which may stimulate certain resonances in traction power supply systems (TPSSs). A windowed selective harmonic elimination pulse-width modulation (SHE-PWM) method...... is proposed to suppress such resonances. Owing to the windowed design and the precalculated solutions, the proposed method covers the wide potential resonant frequency range and addresses the resonant frequency variation while keeping the low switching frequency of the traction converters. The proposed...... windowed SHE-PWM is fully tested with a closed-loop controller in a simulation model with the TPSS and the ac electric locomotive. Comparative simulation results show that the windowed SHE-PWM is an effective alternative that overcomes the resonance suppression limitations of the conventional phase...

  15. Analysis and Mitigation of Dead Time Harmonics in the Single-Phase Full-Bridge PWM Converters with Repetitive Controllers

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Wang, Huai

    2018-01-01

    -Width Modulation (PWM) schemes. Both solutions will contribute to a degradation of the injected current quality. As a consequence, the harmonics induced by the dead time (referred to as "dead time harmonics" hereafter) have to be compensated in order to achieve a satisfactory current quality as required...... by standards. In this paper, the emission mechanism of dead time harmonics in single-phase PWM inverters is thus presented considering the modulation schemes in details. More importantly, a repetitive controller has been adopted to eliminate the dead time effect in single-phase grid-connected PWM converters....... The repetitive controller has been plugged into a proportional resonant-based fundamental current controller so as to mitigate the dead time harmonics and also maintain the control of the fundamental-frequency grid current in terms of dynamics. Simulations and experiments are provided, which confirm...

  16. Design of a ZVS PWM inverter for a brushless DC motor in an EMA application

    Science.gov (United States)

    Bell, J. Brett; Nelms, R. M.; Shepherd, Michael T.

    1993-01-01

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A.

  17. Design of a ZVS PWM inverter for a brushless DC motor in an EMA application

    Science.gov (United States)

    Bell, J. Brett; Nelms, R. M.; Shepherd, Michael T.

    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A.

  18. Digital P.W.M. Control For Induction Motor Drives Using Boxes Theory

    Science.gov (United States)

    Shaker, Mahmoud; Lorenzo, Santiago; Ruiz, J. M.; Martin, A.

    1987-10-01

    Accuraty output torque is necessary to get, when the induction motor drives is fed by an inverter (like P.W.M.). In this paper we presented a new algorithm to control the DC/AC inverter, that is called BOXES algorithm. Boxes Hardware to control an induction motor is also presented. Field-oriented Theory is used in this work to facilitate the motor simulation and, as known, to can used the motor model as state observor. Finally, (Recursive Least Sequare) identification method, and digital freq-uency analysis is used to design the induction motor control algorithm.

  19. Intermittent Misfiring Default Detection and Localisation on a PWM Inverter Using Wavelet Decomposition

    Directory of Open Access Journals (Sweden)

    H. Ben Attia Sethom

    2008-06-01

    Full Text Available This paper presents a method to detect and localize intermittent misfiring default on a Pulse Width Modulation (PWM inverter supplying a squirrel cage induction machine. The proposed method is based on the Discrete Wavelet Transform (DWT technique to analyse stator current signals. The intermittent misfiring detection is performed thanks to the Daubechies wavelet mother in high frequency bands of the stator current signal. The localisation of the phase where the intermittent misfiring occurs is determined by a statistic approach. This approach is based on the computing of mean power characteristics of the detail signals which are obtained from the stator current wavelet decomposition.

  20. Design Research on Three-Phase PWM Rectifier Based on Double Closed Loop Control Technology

    Directory of Open Access Journals (Sweden)

    Guang Ya LIU

    2014-02-01

    Full Text Available Based on the high frequency of three-phase voltage source PWM rectifier, this paper established a mathematical model of three phase current inner ring and outer ring voltage, and put forward the setting method of three phase double closed loop control. Finally, it was verified through simulation. The experimental results show that Three-phase output of DC voltage is stable with the operation of regulating systems, the current flowing into the grid tends to be sinusoidal and power factor is close to 1, which greatly reduce the interference of harmonics on the grid, thus improve grid operation.

  1. Tobacco constituents are mitogenic for arterial smooth-muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Becker, C.G.; Hajjar, D.P.; Hefton, J.M.

    1985-07-01

    Tobacco glycoprotein (TGP) purified from flue-cured tobacco leaves, tar-derived material (TAR), the water soluble, nondialyzable, delipidized extract of cigarette smoke condensate, rutin-bovine serum albumin conjugates, quercetin, and chlorogenic acid are mitogenic for bovine aortic smooth-muscle cells, but not adventitial fibroblasts. The mitogenicity appears to depend on polyphenol epitopes on carrier molecules. Ellagic acid, another plant polyphenol, inhibited arterial smooth-muscle proliferation. These results suggest that a number of ubiquitous, plant-derived substances may influence smooth-muscle cell proliferation in the arterial wall.

  2. Research on the Control Strategy for Grid-side Converter of PWM Doubly Fed Induction Wind Power Generators

    Science.gov (United States)

    Liu, Yifang; Wang, Zhijie; Li, Renfu; Jiang, Xiuchen; Sheng, Gehao; Liu, Tianyu; Liu, Sanming

    2017-05-01

    When the grid voltage drop, over current of transient rotor and over voltage may damage the power electronic devices. The attenuation of electromagnetic torque will lead to speed up. This paper proposes an improved feed-forward control strategy and its application in the PWM converter. When the PWM converter on voltage drops, bus voltage will be more stable. So over current problems of the DFIG rotor side can be reduced, and it also can improve voltage regulation speed of the DC bus voltage and reduce the oscillation amplitude. Furthermore, the stability of doubly fed wind generator system can be improved. The simulation results verify the validity of the modified control strategy.

  3. Cytokine production by porcine mononuclear leukocytes stimulated by mitogens

    Czech Academy of Sciences Publication Activity Database

    Rašková, G.; Kovářů, František; Bártová, J.

    2005-01-01

    Roč. 74, - (2005), s. 521-525 ISSN 0001-7213 R&D Projects: GA ČR GA524/05/0267 Institutional research plan: CEZ:AV0Z50450515 Keywords : cytokine * ELISpot * mitogen Subject RIV: ED - Physiology Impact factor: 0.353, year: 2005

  4. Lectins, Mitogenicity and Seed Germination: A Comparative Study ...

    African Journals Online (AJOL)

    Dr J. T. Ekanem

    2007-05-24

    May 24, 2007 ... generally, e. g. Lactose, but also by Galactose. Secondly, the seeds of A. communis, a plant belonging to the family Moraceae contain a mitogenic haemagglutinin (Artocarpin) that is specifically inhibited by the Melibiose, (6-O-α-. D-galactopyranosyl-D-glucose), but neither by. Lactose nor Galactose4.

  5. Mitogenic Properties Of Lectin From Mucuna Sloanei Seed Extracts ...

    African Journals Online (AJOL)

    Mitogenic properties of lectin from mucuna sloanei seed extracts were studied. The seeds of mucuna sloanie were shelled and ground using an electric grinder. The powder meal was then defatted with petroleum ether, and adjusted to 10 %( w/v) in potassium inorganic phosphates k-pi (A) buffer (pH 7.5). The suspension ...

  6. Identification of a coelomic mitogenic factor in Eisenia foetida earthworm.

    Science.gov (United States)

    Hanusová, R; Bilej, M; Brys, L; De-Baetselier, P; Beschin, A

    1999-02-01

    Coelomic fluid of earthworms Eisenia foetida (Oligochaeta, Annelida) exerts a mitogenic activity on murine splenocytes. Total coelomic fluid was subjected to size-exclusion chromatography and a semi-purified mitogenic fraction (fraction 5) was isolated and further characterized. Both coelomic fluid and the semi-purified fraction 5 block concanavalin A (ConA)-induced spleen cell proliferation but exert a synergistic effect on LPS-triggered spleen cell proliferation. Using a polyclonal antiserum neutralizing the mitogenic activity of the semi-purified fraction 5, a 60-kDa component was identified and named CMF (coelomic mitogenic factor). CMF was found to bind ConA which could account for its ability to inhibit ConA-induced spleen cell proliferation. CMF is present in the coelomic fluid as a trimer of a 20-kDa protein. N-terminal amino acid sequence of monomeric CMF reveals partial sequence homology with phospholipase A2 (PLA2). Moreover, CMF-enriched coelomic fluid fraction 5 exerts phospholipase activity comparable with that of bovine pancreatic PLA2. Our results suggest that coelomic fluid of E. foetida contains a ubiquitous PLA2-like enzyme which might be involved in immune reactions in earthworms such as anti-bacterial mechanisms.

  7. Estimating return levels from maxima of non-stationary random sequences using the Generalized PWM method

    Directory of Open Access Journals (Sweden)

    P. Ribereau

    2008-12-01

    Full Text Available Since the pioneering work of Landwehr et al. (1979, Hosking et al. (1985 and their collaborators, the Probability Weighted Moments (PWM method has been very popular, simple and efficient to estimate the parameters of the Generalized Extreme Value (GEV distribution when modeling the distribution of maxima (e.g., annual maxima of precipitations in the Identically and Independently Distributed (IID context. When the IID assumption is not satisfied, a flexible alternative, the Maximum Likelihood Estimation (MLE approach offers an elegant way to handle non-stationarities by letting the GEV parameters to be time dependent. Despite its qualities, the MLE applied to the GEV distribution does not always provide accurate return level estimates, especially for small sample sizes or heavy tails. These drawbacks are particularly true in some non-stationary situations. To reduce these negative effects, we propose to extend the PWM method to a more general framework that enables us to model temporal covariates and provide accurate GEV-based return levels. Theoretical properties of our estimators are discussed. Small and moderate sample sizes simulations in a non-stationary context are analyzed and two brief applications to annual maxima of CO2 and seasonal maxima of cumulated daily precipitations are presented.

  8. A high efficiency PWM CMOS class-D audio power amplifier

    Science.gov (United States)

    Zhangming, Zhu; Lianxi, Liu; Yintang, Yang; Han, Lei

    2009-02-01

    Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 μA. The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

  9. Immunological changes in human immunodeficiency virus (HIV)-infected individuals during HIV-specific protease inhibitor treatment

    DEFF Research Database (Denmark)

    Ullum, H; Katzenstein, T; Aladdin, H

    1999-01-01

    The present study examines the influence of effective anti-retroviral treatment on immune function, evaluated by a broad array of immunological tests. We followed 12 individuals infected with human immunodeficiency virus (HIV) for 6 months after initiation of combination anti-retroviral treatment...... including a protease inhibitor. Unstimulated and pokeweed mitogen (PWM)-, interleukin (IL)-2- and phytohaemagglutinin (PHA)-stimulated lymphocyte proliferative responses increased during follow-up reaching average levels from 1.3-fold (PHA) to 3.7-fold (PWM) above baseline values. The total CD4+ lymphocyte...... count increased mainly due to increases in numbers of CD4+ CD28+ and CD4+ CD45RO+ cells, whereas increases in numbers of CD4+ CD45RA+ cells contributed little to the increase in CD4+ cell count. The total cytotoxic T-cell (CTL) killing of autologous B cells infected with HIV-encoding recombinant...

  10. Proliferation and telomere length in acutely mobilized blood mononuclear cells in HIV infected patients

    DEFF Research Database (Denmark)

    Søndergaard, S R; Essen, M V; Schjerling, P

    2002-01-01

    The aim of the study was to investigate the mobilization of T cells in response to a stressful challenge (adrenalin stimulation), and to access T cells resided in the peripheral lymphoid organs in HIV infected patients. Seventeen patients and eight HIV seronegative controls received an adrenalin...... infusion for 1 h. Blood was sampled before, during and 1 h after adrenalin infusion. Proliferation and mean telomere restriction fragment length (telomeres) of blood mononuclear cells (BMNC) and purified CD8+ and CD4+ cells were investigated at all time points. In patients, the proliferation to pokeweed...... mitogens (PWM) was lower and decreased more during adrenalin infusion. After adrenalin infusion the proliferation to PWM was restored only in the controls. In all subjects telomeres in CD4+ cells declined during adrenalin infusion. Additionally, the patients had shortened telomeres in their CD8+ cells...

  11. Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters

    Directory of Open Access Journals (Sweden)

    Gabriele Grandi

    2013-08-01

    Full Text Available Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.

  12. Modeling and the analysis of control logic for a digital PWM controller based on a nano electronic single electron transistor

    Directory of Open Access Journals (Sweden)

    Rathnakannan Kailasam

    2008-01-01

    Full Text Available This paper describes the modelling and the analysis of control logic for a Nano-Device- based PWM controller. A comprehensive simple SPICE schematic model for Single Electron transistor has been proposed. The operation of basic Single Electron Transistor logic gates and SET flip flops were successfully designed and their performances analyzed. The proposed design for realizing the logic gates and flip-flops is used in constructing the PWM controller utilized for switching the buck converter circuit. The output of the converter circuit is compared with reference voltage, and when the error voltage and the reference are matched the latch is reset so as to generate the PWM signal. Due to the simplicity and accuracy of the compact model, the simulation time and speed are much faster, which makes it potentially applicable in large-scale circuit simulation. This study confirms that the SET-based PWM controller is small in size, consumes ultra low power and operates at high speeds without compromising any performance. In addition these devices are capable of measuring charges of extremely high sensitivity.

  13. A ZVS PWM control strategy with balanced capacitor current for half-bridge three-level DC/DC converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Chen, Zhe

    2017-01-01

    PWM strategy, which can eliminate the current imbalance among the two input capacitors. Therefore, the proposed control strategy can improve the converter's performance and reliability in: 1) reducing the switching losses and noises of the power switches; 2) balancing the thermal stresses...

  14. Mitogen-activated protein kinase signaling in plants

    DEFF Research Database (Denmark)

    Rodriguez, Maria Cristina Suarez; Petersen, Morten; Mundy, John

    2010-01-01

    Eukaryotic mitogen-activated protein kinase (MAPK) cascades have evolved to transduce environmental and developmental signals into adaptive and programmed responses. MAPK cascades relay and amplify signals via three types of reversibly phosphorylated kinases leading to the phosphorylation of subs...... the Arabidopsis thaliana MAPKs MPK3, 4, and 6 and MAP2Ks MKK1, 2, 4, and 5. Future work needs to focus on identifying substrates of MAPKs, and on understanding how specificity is achieved among MAPK signaling pathways.......Eukaryotic mitogen-activated protein kinase (MAPK) cascades have evolved to transduce environmental and developmental signals into adaptive and programmed responses. MAPK cascades relay and amplify signals via three types of reversibly phosphorylated kinases leading to the phosphorylation...... of substrate proteins, whose altered activities mediate a wide array of responses, including changes in gene expression. Cascades may share kinase components, but their signaling specificity is maintained by spaciotemporal constraints and dynamic protein-protein interactions and by mechanisms that include...

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

    Directory of Open Access Journals (Sweden)

    Koul Sweaty

    2004-06-01

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

  16. Analysis of Multicarrier PWM techniques for Photovoltaic fed Cascaded H-Bridge Multilevel Inverter

    Directory of Open Access Journals (Sweden)

    VENKATRAMAN Thiyagarajan

    2017-05-01

    Full Text Available Recently multilevel inverter technology emerging as an important alternative in the field of high power, medium voltage energy control. The various topologies for multilevel inverters such as diode-clamped, flying capacitor and cascaded H-bridge have been proposed over the years. This paper analysis the performance of a single phase seven level cascaded H-bridge inverter for photovoltaic applications. The Phase Disposition PWM (PDPWM technique is used to generate gate signals. The performance is compared for both sinusoidal reference waveform and trapezoidal reference waveform. The analysis is carried out for different modulation index and different shading pattern of photovoltaic (PV array. The simulation is carried out using MATLAB/SIMULINK software.

  17. Thin grain oriented electrical steel for PWM voltages fed magnetic cores

    Science.gov (United States)

    Belgrand, Thierry; Lemaître, Régis; Benabou, Abdelkader; Blaszkowski, Jonathan; Wang, Chaoyong

    2018-04-01

    This paper reports on performances of high permeability grain oriented electrical steel when used in association with power electronic switching devices. Loss measurement results obtained from the Epstein test, using sinusoidal or various PWM voltages in medium frequency range, show that for both studied thicknesses (HGO 0.23mm and HGO 0.18mm), comparing performances at a fixed induction level between the various situations may not be the most convenient method. The effect of magnetic domain refinement has been investigated. After having shown the interest of lowering the thickness, an alternative way of looking at losses is proposed that may help to design the magnetic core when it comes to the matter of reducing size in considering frequency and magnetization levels.

  18. Advanced Control Strategy of Back-to-Back PWM Converters in PMSG Wind Power System

    Directory of Open Access Journals (Sweden)

    Tan Luong Van

    2015-01-01

    Full Text Available This paper proposes a control scheme of back-to-back PWM converters for the permanent magnet synchronous generator (PMSG wind turbine system. The DC-link voltage can be controlled at the machine-side converter (MSC, while the grid-side converter (GSC controls the grid active power for a maximum power point tracking (MPPT. At the grid fault condition, the DC-link voltage controller is designed using a feedback linearization (FL theory. For the MPPT, a proportional control loop is added to the torque control to reduce the influence of the inertia moment in the wind turbines, which can improve its dynamic performance. The validity of this control algorithm has been verified by the simulation of the 2-MW PMSG wind turbine system.

  19. Internal-Model-Principle-Based Specific Harmonics Repetitive Controller for Grid-Connected PWM Inverters

    Directory of Open Access Journals (Sweden)

    Wenzhou Lu

    2016-01-01

    Full Text Available This paper analyzes the general properties of IMP-based controller and presents an internal-model-principle-based (IMP-based specific harmonics repetitive control (SHRC scheme. The proposed SHRC is effective for specific nk±m order harmonics, with n>m≥0 and k=0,1,2,…. Using the properties of exponential function, SHRC can also be rewritten into the format of multiple resonant controllers in parallel, where the control gain of SHRC is n/2 multiple of that of conventional RC (CRC. Therefore, including SHRC in a stable closed-loop feedback control system, asymptotic disturbance eliminating, or reference tracking for any periodic signal only including these specific harmonic components at n/2 times faster error convergence rate compared with CRC can be achieved. Application examples of SHRC controlled three-phase/single-phase grid-connected PWM inverters demonstrate the effectiveness and advantages of the proposed SHRC scheme.

  20. Multilevel-Dc-Bus Inverter For Providing Sinusoidal And Pwm Electrical Machine Voltages

    Science.gov (United States)

    Su, Gui-Jia [Knoxville, TN

    2005-11-29

    A circuit for controlling an ac machine comprises a full bridge network of commutation switches which are connected to supply current for a corresponding voltage phase to the stator windings, a plurality of diodes, each in parallel connection to a respective one of the commutation switches, a plurality of dc source connections providing a multi-level dc bus for the full bridge network of commutation switches to produce sinusoidal voltages or PWM signals, and a controller connected for control of said dc source connections and said full bridge network of commutation switches to output substantially sinusoidal voltages to the stator windings. With the invention, the number of semiconductor switches is reduced to m+3 for a multi-level dc bus having m levels. A method of machine control is also disclosed.

  1. Mitogen-activated protein kinases in the acute diabetic myocardium

    Czech Academy of Sciences Publication Activity Database

    Strnisková, M.; Barančík, M.; Neckář, Jan; Ravingerová, T.

    2003-01-01

    Roč. 249, 1-2 (2003), s. 59-65 ISSN 0300-8177 R&D Projects: GA MŠk LN00A069 Grant - others:VEGA(SK) 2/2063/22 Institutional research plan: CEZ:AV0Z5011922 Keywords : experimental diabetes * ischemia * mitogen-activated protein kinases (MAPK) Subject RIV: ED - Physiology Impact factor: 1.763, year: 2003

  2. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    Science.gov (United States)

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.

    2011-08-01

    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  3. Dynamic Sliding Mode Evolution PWM Controller for a Novel High-Gain Interleaved DC-DC Converter in PV System

    Directory of Open Access Journals (Sweden)

    Taizhou Bei

    2014-01-01

    Full Text Available Considering the disadvantages of the traditional high-gain DC-DC converter such as big size, high voltage stress of switches, and large input current ripple, a novel high-gain interleaved boost converter with coupled-inductor and switched-capacitor was proposed correspondingly and the operation principle together with the steady-state analysis of this converter was also described. Besides, a new control approach-dynamic sliding mode evolution PWM controller (DSME PWM for the novel topological converter based on both dynamic evolution and sliding mode control was also presented. From the simulation results and experimental validation the proposed converter can fulfill high-gain boost, low ripple of both the input current and the output voltage. Furthermore, MPPT technique can be also achieved in a short time by simulation. The efficiency and stability of the converter proposed in this paper can be improved.

  4. A Novel Electronically Controllable of Current-mode Level Shifted Multicarrier PWM Based on MO-CFTA

    OpenAIRE

    W. Kongnun; A. Aurasopon

    2013-01-01

    This paper proposes the application of an electronically controlled current-mode for a level shifted multicarrier PWM generator. The proposed circuit consists of two multiple-output current follower transconductance amplifiers (MO-CFTAs) for the multiple-output triangular generator and four current follower transconductance amplifiers (CFTAs) for the signal comparator. The characteristics of the circuit are as follows: the current output can be controlled by bias current, the maximum amplitud...

  5. A single-phase PWM controlled AC to DC converter based on control of unity displacement power factor

    OpenAIRE

    Funabiki, Shigeyuki

    1990-01-01

    A modified pulse-width modulation (PWM) technique that improves the displacement power factor and the input power factor of a single-phase AC to DC converter is discussed. The modified converter is shown to have a high input power factor and allows the of DC voltage from zero to more than the maximum value of the source voltage. The displacement power factor is unity, and the input power factor is almost unity in the wide range of current command

  6. Astrocyte Mitogen Inhibitor Related to Epidermal Growth Factor Receptor

    Science.gov (United States)

    Nieto-Sampedro, Manuel

    1988-06-01

    Epidermal growth factor (EGF) is a well-characterized polypeptide hormone with diverse biological activities, including stimulation of astrocyte division. A soluble astrocyte mitogen inhibitor, immunologically related to the EGF receptor, is present in rat brain. Injury to the brain causes a time-dependent reduction in the levels of this inhibitor and the concomitant appearance of EGF receptor on the astrocyte surface. Intracerebral injection of antibody capable of binding the inhibitor caused the appearance of numerous reactive astrocytes. EGF receptor-related inhibitors may play a key role in the control of glial cell division in both normal and injured brain.

  7. Highly Sensitive Temperature Sensors Based on Fiber-Optic PWM and Capacitance Variation Using Thermochromic Sensing Membrane.

    Science.gov (United States)

    Khan, Md Rajibur Rahaman; Kang, Shin-Won

    2016-07-09

    In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R² ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system.

  8. An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.

    Science.gov (United States)

    Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

    2013-11-01

    This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  9. A PWM Controller of a Full Bridge Single-Phase Synchronous Inverter for Micro-Grid System

    Science.gov (United States)

    Rahman, Tawfikur; Motakabber, S. M. A.; Ibrahimy, M. I.; Raghib, Aliza ‘Aini Binti Md Ralib@ Md

    2017-12-01

    Nowadays, microgrid system technology is becoming popular for small area power management systems. It is essential to be less harmonic-distortion and high efficiency of the inverter for microgrid applications. Pulse width modulation (PWM) controller is a conventional switching control technique which is suitable to use in the microgrid connected power inverter system. The control method and algorithm of this technique are challenging, and different approaches are required to avoid the complexity for a customized solution of the microgrid application. This paper proposes a comparative analysis of different controller and their operational methods. A PWM controller is used to reduce the ripple voltage noise while a continuous current mode provides a small output ripple which gives steady-state error as zero on fundamental and cutoff frequency. To reduce the ripple current, higher frequency harmonic distortion, switching loss and phase noise, LC low pass filter is used on either side of input and output terminals. The proposed inverter is designed by MATLAB 2016a simulation software. A balanced load resistance (RL = 20.5 Ω) of star configuration and a dual input DC voltage of ± 35V are considered. In this design, the circuit parameters, the fundamental frequency of 50 Hz, the PWM duty cycle of 95%, the cutoff frequency of the switching controller of 33 kHz are considered. The inverter in this paper exhibits THD of 0.44% and overall efficiency approximately of 98%. The proposed inverter is expected to be suitable for microgrid applications.

  10. Highly Sensitive Temperature Sensors Based on Fiber-Optic PWM and Capacitance Variation Using Thermochromic Sensing Membrane

    Science.gov (United States)

    Khan, Md. Rajibur Rahaman; Kang, Shin-Won

    2016-01-01

    In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R2 ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system. PMID:27409620

  11. Single-carrier sinusoidal PWM-equivalent selective harmonic elimination for a five-level voltage source converter

    Energy Technology Data Exchange (ETDEWEB)

    Dahidah, Mohamed S.A. [School of Electrical and Electronic Engineering, The University of Nottingham, Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor (Malaysia); Agelidis, Vassilios G. [School of Electrical and Information Engineering, The University of Sydney, NSW (Australia)

    2008-11-15

    The paper presents a new variation of selective harmonic elimination pulse-width modulation (SHE-PWM) technique suitable for a high-power five-level converter used in constant frequency utility applications. The governing system of equations associated with the elimination of specific harmonics is defined based on an equal number of switching transitions when compared against the single-carrier sinusoidal PWM (SC-SPWM) technique. For this paper, it is assumed that the modulating signal (triangular carrier) of the equivalent SC-SPWM method has twenty per unit frequency. The switching transitions for every quarter period are therefore distributed between the converter levels according to the modulation index of SC-SPWM. It is confirmed that the proposed technique offers significantly higher converter bandwidth and higher dc bus utilization for the same switching transitions. Furthermore, the proposed SHE-PWM offers better harmonic performance compared to its SC-SPWM counterpart. Selected solutions for the switching transitions are presented and verified experimentally in order to confirm the effectiveness of the proposed technique. (author)

  12. Math Model and Calculation Analysis of Inter-harmonic of Double PWM Speed Control System in Distribution Network

    Directory of Open Access Journals (Sweden)

    Yang Wen-Huan

    2014-11-01

    Full Text Available Aiming at the problem that the distribution network voltage will fluctuate because of the inter-harmonic currents injected into the network by double PWM speed control system when regulating the speed of the asynchronous motor, we established the inter-harmonic current math model of double PWM speed control system according to switching function based on a real bridge crane. The distribution law of the inter-harmonic is got by calculating the grid-side currents and their spectrum while letting the motor run at different quadrants and frequencies. The result which is verified by simulation and experiment shows that the content of the inter harmonic currents is more than that of harmonic currents in double PWM speed control system, the frequency of the inter harmonics of the grid-side current mainly focus on the scope lower than the fundamental frequency, and when the motor runs at low frequencies, the THD of the grid-side current is high. The result has verified the reason why the voltage of a bridge crane distribution system of a deepwater port in Shanghai flickers.

  13. A High-Precision Control for a ZVT PWM Soft-Switching Inverter to Eliminate the Dead-Time Effect

    Directory of Open Access Journals (Sweden)

    Baoquan Kou

    2016-07-01

    Full Text Available Attributing to the advantages of high efficiency, low electromagnetic interference (EMI noise and closest to the pulse-width-modulation (PWM converter counterpart, zero-voltage-transition (ZVT PWM soft-switching inverters are very suitable for high-performance applications. However, the conventional control algorithms intended for high efficiency generally results in voltage distortion. Thus, this paper, for the first time, proposes a high-precision control method to eliminate the dead-time effect through controlling the auxiliary current in the auxiliary resonant snubber inverter (ARSI, which is a typical ZVT PWM inverter. The dead-time effect of ARSI is analyzed, which is distinguished from hard-switching inverters. The proposed high-precision control is introduced based on the investigation of dead-time effect. A prototype was developed to verify the effectiveness of the proposed control. The experimental results shows that the total harmonic distortion (THD of the output current of the ARSI can be reduced compared with that of the hard-switching inverter, because the blanking delay error is eliminated. The quality of the output current and voltage can be further improved by utilizing the proposed control method.

  14. Localised mitogenic activity in horses following infection with Streptococcus equi.

    Science.gov (United States)

    McLean, R; Rash, N L; Robinson, C; Waller, A S; Paillot, R

    2015-06-01

    Streptococcus equi subspecies equi (S. equi) is the causative agent of strangles, a highly contagious upper respiratory disease of equids. Streptococcus equi produces superantigens (sAgs), which are thought to contribute to strangles pathogenicity through non-specific T-cell activation and pro-inflammatory response. Streptococcus equi infection induces abscesses in the lymph nodes of the head and neck. In some individuals, some abscess material remains into the guttural pouch and inspissates over time to form chondroids which can harbour live S. equi. The aim of this study was to determine the sites of sAg production during infection and therefore improve our understanding of their role. Abscess material, chondroids and serum collected from Equidae with signs of strangles were tested in mitogenic assays. Mitogenic sAg activity was only detected in abscess material and chondroids. Our data support the localised in vivo activity of sAg during both acute and carrier phases of S. equi infection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Engineering a Therapeutic Lectin by Uncoupling Mitogenicity from Antiviral Activity

    Science.gov (United States)

    Swanson, Michael D.; Boudreaux, Daniel M.; Salmon, Loïc; Chugh, Jeetender; Winter, Harry C.; Meagher, Jennifer L.; André, Sabine; Murphy, Paul V.; Oscarson, Stefan; Roy, René; King, Steven; Kaplan, Mark H.; Goldstein, Irwin J.; Tarbet, E. Bart; Hurst, Brett L.; Smee, Donald F.; de la Fuente, Cynthia; Hoffmann, Hans-Heinrich; Xue, Yi; Rice, Charles M.; Schols, Dominique; Garcia, J. Victor; Stuckey, Jeanne A.; Gabius, Hans-Joachim; Al-Hashimi, Hashim M.; Markovitz, David M.

    2015-01-01

    Summary A key effector route of the Sugar Code involves lectins that exert crucial regulatory controls by targeting distinct cellular glycans. We demonstrate that a single amino acid substitution in a banana lectin, replacing histidine 84 with a threonine, significantly reduces its mitogenicity while preserving its broad-spectrum antiviral potency. X-ray crystallography, NMR spectroscopy, and glycocluster assays reveal that loss of mitogenicity is strongly correlated with loss of pi-pi stacking between aromatic amino acids H84 and Y83, which removes a wall separating two carbohydrate binding sites, thus diminishing multivalent interactions. On the other hand, monovalent interactions and antiviral activity are preserved by retaining other wild-type conformational features and possibly through unique contacts involving the T84 side chain. Through such fine-tuning, target selection and downstream effects of a lectin can be modulated so as to knock down one activity while preserving another, thus providing tools for therapeutics and for understanding the Sugar Code. PMID:26496612

  16. Harmonic Analyzing of the Double PWM Converter in DFIG Based on Mathematical Model

    Directory of Open Access Journals (Sweden)

    Jing Liu

    2017-12-01

    Full Text Available Harmonic pollution of double fed induction generators (DFIGs has become a vital concern for its undesirable effects on power quality issues of wind generation systems and grid-connected system, and the double pulse width modulation (PWMconverter is one of the main harmonic sources in DFIGs. Thus the harmonic analysis of the converter in DFIGs is a necessary step to evaluate their harmonic pollution of DFIGs. This paper proposes a detailed harmonic modeling method to discuss the main harmonic components in a converter. In general the harmonic modeling could be divided into the low-order harmonic part (up to 30th order and the high-order harmonic part (greater than order 30 parts in general. The low-order harmonics are produced by the circuit topology and control algorithm, and the harmonic component will be different if the control strategy changes. The high-order harmonics are produced by the modulation of the switching function to the dc variable. In this paper, the low-order harmonic modeling is established according to the directions of power flow under the vector control (VC, and the high-order harmonic modeling is established by the switching function of space vector PWM and dc currents. Meanwhile, the simulations of harmonic a components in a converter are accomplished in a real time digital simulation system. The results indicate that the proposed modeling could effectively show the harmonics distribution of the converter in DFIGs.

  17. Phase shift PWM with double two-switch bridge for high power capacitor charging

    International Nuclear Information System (INIS)

    Karandikar, U.S.; Singh, Yashpal; Thakurta, A.C.

    2013-01-01

    Pulse power supply systems working at higher voltage and high repetition rate demands for higher power from capacitor chargers. Capacitor charging requirement become more challenging in such cases. In pulse power circuits, energy storage capacitor should be charged to its desired voltage before the next switching occurs. It is discharged within a small time, delivering large pulse power. A capacitor charger has to work with wide load variation repeatedly. Many schemes are used for this purpose. The proposed scheme aims at reducing stresses on switches by reducing peak current and their evils. A high voltage power supply is designed for capacitor charging. The proposed scheme is based on a Phase-Shifted PWM without using any extra component to achieve soft switching. Indirect constant average current capacitor charging is achieved with a simple control scheme. A double two-switch bridge is proposed to enhance reliability. Power supply has been developed to charge a capacitor of 50 μF to 2.5 kV at 25 Hz. (author)

  18. Desain dan Realisasi Sistem Komunikasi Cahaya Tampak untuk Streaming Teks berbasis PWM

    Directory of Open Access Journals (Sweden)

    Trio Adiono

    2017-12-01

    Full Text Available The design and implementation of visible light communication systems for transmitting digital data (texts have been discussed in this paper. Then, two evaluations were performed also, i.e. the demonstration of streaming text through the visible light as a proof-of-concept system design. The next evaluation is a BER measurement intended to know the VLC system performance quantitatively. The value of BER against the several parameters: by the variation of distance and its reception angle. The proposed VLC system works well until the photodiode reception angle to the LEDs up to 50°. According to evaluation, our system can operate optimally within 30 – 80 cm or 50 – 130 cm of optical channel range depending on the Gain setting option. To support the reliability of noise from ambient light and interference lamps such as fluorescent lamps, the filters circuit are employed: high pass filter and DC-offset remover. Based on the BER analysis, the filters can compensate the problem of ambient light noise (DC-offset signal and interference lamp (100-150 Hz of carrier frequency. The speed of data-rate obtained with 1-PWM modulation and the low-cost analog component is 3.3 kbps.

  19. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    Science.gov (United States)

    Santiago, Walter

    2004-01-01

    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  20. Changes in some pro-and anti-inflammatory cytokines produced by bovine peripheral blood mononuclear cells following foot and mouth disease vaccination

    Directory of Open Access Journals (Sweden)

    N. Delirezh

    2016-09-01

    Full Text Available Interleukin (IL-17 is exclusively produced by CD4 helper T-cells upon activation. It most often acts as a pro-inflammatory cytokine, which stimulates the release of pro-inflammatory cytokines IL-6, IL-8, TNF-α, and granulocyte-macrophage colony-stimulating factor (GM-CSF. In this study, we studied the in-vitro IL-17 response to specific antigens and a variety of mitogens and compared the IL-17 response to IL-2, IL-4, IL-5, IL-6, IL-10, and IFN-γ responses. We used a foot and mouth disease (FMD vaccine as specific antigens and mitogens (phytohemagglutinin [PHA], pokeweed mitogen [PWM], and concanavalin A [Con A] to stimulate peripheral blood mononuclear cells (PBMCs of vaccinated calves. Cell culture supernatant was harvested and analyzed for cytokines, using commercially available bovine ELISA kits. The mitogens induced a significant increase in IL-17 production. IL-17 was produced at high levels in response to the T cell-stimulated mitogens, PHA, and Con A, and at low levels in response to PWM mitogens. In contrast, level of the produced IL-17 cytokines in response to the FMDV antigens was lower as compared to those produced by mitogens. The FMDV antigens and mitogens significantly increased IL-17 production. There was not a correlation between IL-17 production and type-1 cytokine, IFN-γ, and IL-2, while there was a correlation between type-2 cytokine, IL-4, and IL-5 at either cytokine level produced by PBMCs stimulated by FMDV antigens. Moreover, there was an interaction between IL-17 and IL-6, that is, as IL-6 cytokine level elevated or diminished, IL-17 cytokine level increased or decreased, as well.

  1. Development of a chemically defined medium and discovery of new mitogenic growth factors for mouse hepatocytes: mitogenic effects of FGF1/2 and PDGF.

    Science.gov (United States)

    Bowen, William C; Michalopoulos, Amantha W; Orr, Anne; Ding, Michael Q; Stolz, Donna B; Michalopoulos, George K

    2014-01-01

    Chemically defined serum-free media for rat hepatocytes have been useful in identifying EGFR ligands and HGF/MET signaling as direct mitogenic factors for rat hepatocytes. The absence of such media for mouse hepatocytes has prevented screening for discovery of such mitogens for mouse hepatocytes. We present results obtained by designing such a chemically defined medium for mouse hepatocytes and demonstrate that in addition to EGFR ligands and HGF, the growth factors FGF1 and FGF2 are also important mitogenic factors for mouse hepatocytes. Smaller mitogenic response was also noticed for PDGF AB. Mouse hepatocytes are more likely to enter into spontaneous proliferation in primary culture due to activation of cell cycle pathways resulting from collagenase perfusion. These results demonstrate unanticipated fundamental differences in growth biology of hepatocytes between the two rodent species.

  2. A Novel Soft Switching PWM Power Frequency Converter with Non DC Smoothing Filter Link for Consumer High Frequency Induction Heating

    Science.gov (United States)

    Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo

    In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.

  3. Zero-Voltage Switching PWM Strategy Based Capacitor Current-Balancing Control for Half-Bridge Three-Level DC/DC Converter

    DEFF Research Database (Denmark)

    Liu, Dong; Deng, Fujin; Zhang, Qi

    2018-01-01

    The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation...... modes is proposed. Based on the proposed ZVS PWM strategy, a capacitor current-balancing control is proposed for the HBTL DC/DC converter, where the currents on the two input capacitors can be kept balanced by alternating the two operation modes of the proposed ZVS PWM strategy. Therefore, the proposed...... control strategy can improve the performance and reliability of the converter in the aspect of balancing the thermal stresses and lifetimes among the two input capacitors. Finally, simulation and experimental studies are conducted and results verify the proposed control strategy....

  4. Análisis y diseño de un rectificador trifásico elevador PWM

    OpenAIRE

    García Bragado, Alejandro

    2010-01-01

    El principal objetivo de este proyecto es el de analizar, modelar, simular y validar experimentalmente un rectificador trifásico controlado tipo elevador, a partir de sus ecuaciones matemáticas. Para ello se utilizará la aplicación informática Matlab®, y su entorno Simulink®, junto con la herramienta de simulación PSIM®. Posteriormente se diseñará un sistema de control basado en la modulación por ancho de pulso (PWM) con las mismas herramientas para implementar dicho sistema de control en un ...

  5. Comparison of Current Control Methods on Carrier Based VSI-PWM Inverter Drives From Line Power Quality Aspect

    Directory of Open Access Journals (Sweden)

    Muh. Imran Hamid

    2008-08-01

    Full Text Available This paper describes simulation result of two methods in current controlling for carrier based VSI-PWM inverter: hysteresis and ramp comparison control. The simulation is useful in selection of ASDs and generally–converter, from power quality point of view. Simulation results show that both ramp comparison and hysteresis control methods gives difference characteristic on line voltage and line current. A ramp comparison method is better in form of lower effect on line current distortion compare with hysteresis control method. Meanwhile, for line voltage distortion, hysteresis control seen better.

  6. One-Stage and Two-Stage Schemes of High Performance Synchronous PWM with Smooth Pulses-Ratio Changing

    DEFF Research Database (Denmark)

    Oleschuk, V.; Blaabjerg, Frede

    2002-01-01

    This paper presents detailed description of one-stage and two-stage schemes of a novel method of synchronous, pulsewidth modulation (PWM) for voltage source inverters for ac drive application. The proposed control functions provide accurate realization of different versions of voltage space vector...... modulation with synchronization of the voltage waveform of the inverter and with smooth pulse-ratio changing. Voltage spectra do not contain even harmonic and sub-harmonics (combined harmonics) during the whole control range including the zone of overmodulation. Examples of determination of the basic control...

  7. Cytogenic follow-up studies in six radiation accident victims 16 and 17 years post-exposure

    International Nuclear Information System (INIS)

    Littlefield, L.G.; Joiner, E.E.

    1978-01-01

    Detailed cytogenetic evaluations were recently conducted in cultured lymphocytes from six men accidentally exposed to fission neutron and gamma radiation in 1958 (dose range 22.8-365 rads). Two-day lymphocyte cultures stimulated with phytohaemagglutinin (PHA) and seven-day cultures stimulated with pokeweed mitogen (PWM) were initiated on all six men for routine microscopic and karyotypic analysis. PHA-stimulated cultures from the two men with the highest exposures were also evaluated using Giemsa-banding procedures. Approximately 9% of the metaphases in the PHA cultures and 11% of the metaphases in the PWM cultures were found to have residual radiation-induced aberrations (symmetrical and asymmetrical exchanges and deletions). In both the PHA and PWM cultures the highest frequencies of lesions were observed in preparations from three men with the highest radiation exposures. Among the abnormal metaphases from the various PHA cultures five possible clones were identified (two or more cells having apparently identical lesions) whereas no stemlines were detected in the PWM cultures. The frequency of stable lesions in 92 banded metaphases from the two men with the highest exposures did not differ significantly from the frequency of lesions detected in 300 metaphases evaluated with routine staining and karyotypic procedures. These data suggest that radiation-damaged lymphocytes responsive to mitogenic stimulation by PHA and PWM may survive for many years following exposure, that the frequency of lymphocytes with persistent aberrations can be roughly correlated with dose, and that in some instances cells bearing 'stable' radiation-induced lesions may propagate in vivo. The findings also show that banding procedures, compared with routine microscopic and karyotypic methods, do not significantly improve the rate of detection of symmetrical lesions in lymphocytes from irradiated persons

  8. DC Bus Control of Back-to-Back Connected Two-Level PWM Rectifier-Five-Level NPC Voltage Source Inverter to Torque Ripple Reduction in Induction Motor

    Directory of Open Access Journals (Sweden)

    Abdelkrim Thameur

    2015-01-01

    Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.

  9. A Medium-Voltage Motor Drive with a Modular Multilevel PWM Inverter Part II. Startup Method and Performance

    Science.gov (United States)

    Nishimura, Kazutoshi; Hagiwara, Makoto; Akagi, Hirofumi

    This paper presents a medium-voltage motor drive with a modular multilevel PWM inverter, and focuses on a startup method and its performance. It is formed by six modular arms, each of which consists of a cascaded stack of multiple bidirectional chopper-cells. The frequency of the dominant ac-voltage fluctuation is equal to the motor (inverter) frequency. These fluctuations occur in the dc capacitor of each chopper-cell, and the magnitude of the fluctuation is inversely proportional to the motor frequency. Because of the increased voltage fluctuation in low-frequency regions, the so-called “volt-per-hertz control” cannot be applied in motor starting. The startup method proposed in this paper is suitable for a motor drive with the modular multilevel PWM inverter. It enables the motor to produce a startup torque loaded on the motor at an initial amplitude and a fixed frequency of the inverter while taking into account constraints on the motor current and the ac-voltage fluctuation. The validity of the startup method as well as the startup performance is confirmed by experiment and simulation.

  10. Phase Opposition Disposition PWM Strategy and Hardware in the Loop Validation for a 3-SM Modular Multilevel Converter

    Directory of Open Access Journals (Sweden)

    Imen Ouerdani

    2017-03-01

    Full Text Available This paper focuses on the carrier disposition Pulse Width Modulation (PWM strategies for Modular Multilevel Converters (MMC. The authors propose a new Phase Opposition Disposition PWM (PODPWM scheme applicable regardless of the converter’s sub-modules number. Moreover, a capacitor voltage sorting algorithm is synthesized aiming to ensure the converter’s balanced operation. Simulation results of a 3.6 MVA, 3-SM-MMC are presented and discussed. In addition, a Hardware In the Loop (HIL validation of the proposed PODPWM has been made using Field Programmable Gate Array (FPGA target. The actual power system (the 3-SM-MMC and the 3-phase RL load is then replaced by its real-time emulator. The latter is interfaced to the PODPWM control under test and both are implemented and run altogether in the same Xilinx XC7Z020 Zynq FPGA device. The obtained real-time HIL emulation results are presented and compared to the offline simulation results.

  11. Elevated CO2 increases Cs uptake and alters microbial communities and biomass in the rhizosphere of Phytolacca americana Linn (pokeweed) and Amaranthus cruentus L. (purple amaranth) grown on soils spiked with various levels of Cs

    International Nuclear Information System (INIS)

    Song, Ningning; Zhang, Ximei; Wang, Fangli; Zhang, Changbo; Tang, Shirong

    2012-01-01

    General concern about increasing global atmospheric CO 2 levels owing to the ongoing fossil fuel combustion and elevated levels of radionuclides in the environment, has led to growing interest in the responses of plants to interactive effects of elevated CO 2 and radionuclides in terms of phytoremediation and food safety. To assess the combined effects of elevated CO 2 and cesium contamination on plant biomass, microbial activities in the rhizosphere soil and Cs uptake, Phytolacca americana Linn (pokeweed, C3 specie) and Amaranthus cruentus L. (purple amaranth, C4 specie) were grown in pots of soils containing five levels of cesium (0, 100, 300, 500 and 1000 mg Cs kg −1 ) under two levels of CO 2 (360 and 860 μL L −1 , respectively). Shoot and root biomass of P. americana and Amaranthus crentus was generally higher under elevated CO 2 than under ambient CO 2 for all treatments. Both plant species exhibited higher Cs concentration in the shoots and roots under elevated CO 2 than ambient CO 2 . For P. americana grown at 0, 100, 300, 500 and 1000 mg Cs kg −1 , the increase magnitude of Cs concentration due to elevated CO 2 was 140, 18, 11, 34 and 15% in the shoots, and 150, 20, 14, 15 and 19% in the roots, respectively. For A. cruentus, the corresponding value was 118, 28, 21, 14 and 17% in the shoots, and 126, 6, 11, 17 and 22% in the roots, respectively. Higher bioaccumulation factors were noted for both species grown under elevated CO 2 than ambient CO 2 . The populations of bacteria, actinomycetes and fungi, and the microbial C and N in the rhizosphere soils of both species were higher at elevated CO 2 than at ambient CO 2 with the same concentration of Cs. The results suggested that elevated CO 2 significantly affected plant biomass, Cs uptake, soil C and N concentrations, and community composition of soil microbes associated with P. americana and A. cruentus roots. The knowledge gained from this investigation constitutes an important advancement in

  12. A Schwann cell mitogen accompanying regeneration of motor neurons.

    Science.gov (United States)

    Livesey, F J; O'Brien, J A; Li, M; Smith, A G; Murphy, L J; Hunt, S P

    1997-12-11

    Motor neurons are the only adult mammalian neurons of the central nervous system to regenerate following injury. This ability is dependent on the environment of the peripheral nerve and an intrinsic capacity of motor neurons for regrowth. We report here the identification, using a technique known as messenger RNA differential display, of an extracellular signalling molecule, previously described as the pancreatic secreted protein Reg-2, that is expressed solely in regenerating and developing rat motor and sensory neurons. Axon-stimulated Schwann cell proliferation is necessary for successful regeneration, and we show that Reg-2 is a potent Schwann cell mitogen in vitro. In vivo, Reg-2 protein is transported along regrowing axons and inhibition of Reg-2 signalling significantly retards the regeneration of Reg-2-containing axons. During development, Reg-2 production by motor and sensory neurons is regulated by contact with peripheral targets. Strong candidates for peripheral factors regulating Reg-2 production are cytokines of the LIF/CNTF family, because Reg-2 is not expressed in developing motor or sensory neurons of mice carrying a targeted disruption of the LIF receptor gene, a common component of the receptor complexes for all of the LIF/CNTF family.

  13. Interleaved Boost-Half-Bridge Dual–Input DC-DC Converter with a PWM plus Phase-Shift Control for Fuel Cell Applications

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    the performance of the proposed PWM converter. The principle of operation is analyzed and some design considerations are discussed. Simulation results using PLECS are given to verify the proposed analysis and design. An experimental converter prototype has been designed, constructed and tested in the laboratory...

  14. Loss Distribution Analysis of Three-Level Active Neutral-Point-Clamped (3L-ANPC) Converter with Different PWM Strategies

    DEFF Research Database (Denmark)

    Zhang, Gang; Yang, Yongheng; Iannuzzo, Francesco

    2016-01-01

    The three-level (3L) Active Neutral-Point-Clamped (ANPC) topology has been introduced to resolve the uneven loss distribution issue in the classical 3L Neutral-Point-Clamped (NPC) topology. This Pulse-Width-Modulation (PWM) strategy is then an important means to fully explore the potential benefits...

  15. Mitogen activated protein kinase signaling in the kidney: Target for intervention?

    NARCIS (Netherlands)

    de Borst, M.H.; Wassef, L.; Kelly, D.J.; van Goor, H.; Navis, Ger Jan

    2006-01-01

    Mitogen activated protein kinases (MAPKs) are intracellular signal transduction molecules, which connect cell-surface receptor signals to intracellular processes. MAPKs regulate a range of cellular activities including cell proliferation, gene expression, apoptosis, cell differentiation and cytokine

  16. Heat- and radiation effects on the hemaglutinating- and mitogenic activity of phytohemaglutinins

    International Nuclear Information System (INIS)

    Mancini Filho, J.; Vizeu, D.M.; Lajolo, F.M.

    1975-01-01

    The effect of ionizing radiation on hemaglutinating and mitogenic activity of phytohemaglutinins (PHA) in solution is studied. 10 Krad (electron beam) are neede for the destruction of 50% of the aglutinating capacity. The mitogenic effect is more resistent to irradiation (70 Krad for 50% inactivation) may be because both effects are due to different molecules. Changes were also followed by electrophoresis in polyacrylamida. The resistence to irradiation showed to be exponential function of the concentration of PHA in solution. (author) [pt

  17. Manifestation of radiaton injury of human lymphocytes using PHA mitogenic stimulation in different culture systems

    International Nuclear Information System (INIS)

    Horky, J.

    1986-01-01

    The proliferative response of human lymphocytes to phytohemagglutinin in vitro is affected by X-irradiation. Dose-related changes in mitogenic stimulation of irradiated lymphocytes were compared for two culture systems - the cultivation of separated lymphocytes and the cultivation of whole blood. In the whole blood cultures, the proliferative activity of stimulated lyphocytes was markedly and reproducibly depressed by irradiation. An exponential curve could be fitted to the values of mitogenic response within a dose range from 0 to 2.5 Gy with high correlation. In a modified test where the mitogenic stimulus was given after a 24 h delay, depression in the response was even more pronounced. Radiosensitivity of human lymphocytes as determined by means of mitogenic stimulation in the whole blood cultures appears to be a characteristic individual feature. The mean D 37 value of the radiation-induced depression in mitogenic response in a group of 20 healthy donors was 2.5 Gy in the standard test and 2.0 Gy in the test with a delayed mitogenic stimulus. In contrast, the data obtained from separated lymphocyte cultures were characterized by a high degree of test-to-test variability and by much lower radiosensitivity. The possible mechanisms of these distinctive manifestations of the same primary radiation injury are discussed. (author) 3 tabs., 2 figs., 12 refs

  18. Distribution of kappa and lambda light chain isotypes among human blood immunoglobulin-secreting cells after vaccination with pneumococcal polysaccharides

    DEFF Research Database (Denmark)

    Heilmann, C; Barington, T

    1989-01-01

    The light chain isotype of immunoglobulin-secreting blood cells was investigated by means of monolayer plaque-forming cell assays allowing direct immunofluorescence staining for cytoplasmic kappa and lambda light chains in centre cells. The study revealed that cultured, polyclonally activated...... pokeweed mitogen (PWM) and Epstein-Barr virus (EBV), IgM-, IgG- and IgA-secreting cells expressed the kappa light chain isotype in approximately 65% of the cells. IgM- and IgG-secreting cells induced by vaccination with pneumococcal polysaccharides had a similar percentage of kappa light chain......-containing cells. In contrast, IgA-secreting cells induced by vaccination with pneumococcal polysaccharides showed a different (bimodal) distribution as regards expression of kappa light chain. The majority (56%) of the investigated individuals expressed kappa light chain in approximately 50% of the cells...

  19. PWM Regulation of Grid-Tied PV System on the Base of Photovoltaic-Fed Diode-Clamped Inverters

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2015-12-01

    Full Text Available Investigation of grid-tied photovoltaic system on the base of two diode-clamped inverters, controlled by specific algorithms of pulse-width modulation (PWM, has been done. This system includes two strings of photovoltaic panels feeding two diode-clamped inverters. The outputs of inverters are connected with the corresponding windings on the primary side of three-phase transformer, connected with a grid. In order to reduce phase voltage distortion and to increase efficiency of operation of the system, special scheme of control and modulation of inverters has been used, providing minimization of common-mode voltages and voltage waveforms symmetries under different operating conditions. Detailed simulation of processes in this photovoltaic-fed power conversion system has been executed. The results of simulations verify good performance of photovoltaic system regulated in accordance with specific strategy of control and modulation.

  20. Multi Channels PWM Controller for Thermoelectric Cooler Using a Programmable Logic Device and Lab-Windows CVI

    Directory of Open Access Journals (Sweden)

    Eli FLAXER

    2008-09-01

    Full Text Available We present a complete design of a multi channels PID controller for Thermoelectric Cooler (TEC using a pulse width modulation (PWM technique implemented by a dedicated programmable logic device (PLD programmed by VHDL. The PID control loop is implemented by software written by National Instrument Lab-Windows CVI. Due to the fact that the implementation is by a VHDL and PLD the design is modular, as a result, the circuit is very compact in size and very low cost as compared to any commercial product. In addition, since the control loop is implemented by software running on a personal computer (PC using a C language, it is easy to adjust the controller to various environmental conditions and for a width range of sensors like: a thermo couple (TC, thermistor, resistance temperature detectors (RTD etc. We demonstrate the performance of this circuit as a controller for a small incubator using thermistor as the temperature sensor.

  1. A nonlinear adaptive backstepping approach applied to a three phase PWM AC-DC converter feeding induction heating

    Science.gov (United States)

    Hadri-Hamida, A.; Allag, A.; Hammoudi, M. Y.; Mimoune, S. M.; Zerouali, S.; Ayad, M. Y.; Becherif, M.; Miliani, E.; Miraoui, A.

    2009-04-01

    This paper presents a new control strategy for a three phase PWM converter, which consists of applying an adaptive nonlinear control. The input-output feedback linearization approach is based on the exact cancellation of the nonlinearity, for this reason, this technique is not efficient, because system parameters can vary. First a nonlinear system modelling is derived with state variables of the input current and the output voltage by using power balance of the input and output, the nonlinear adaptive backstepping control can compensate the nonlinearities in the nominal system and the uncertainties. Simulation results are obtained using Matlab/Simulink. These results show how the adaptive backstepping law updates the system parameters and provide an efficient control design both for tracking and regulation in order to improve the power factor.

  2. Vibration and acoustic noise emitted by dry-type air-core reactors under PWM voltage excitation

    Science.gov (United States)

    Li, Jingsong; Wang, Shanming; Hong, Jianfeng; Yang, Zhanlu; Jiang, Shengqian; Xia, Shichong

    2018-05-01

    According to coupling way between the magnetic field and the structural order, structure mode is discussed by engaging finite element (FE) method and both natural frequency and modal shape for a dry-type air-core reactor (DAR) are obtained in this paper. On the basis of harmonic response analysis, electromagnetic force under PWM (Pulse Width Modulation) voltage excitation is mapped with the structure mesh, the vibration spectrum is gained and the consequences represents that the whole structure vibration predominates in the radial direction, with less axial vibration. Referring to the test standard of reactor noise, the rules of emitted noise of the DAR are measured and analyzed at chosen switching frequency matches the sample resonant frequency and the methods of active vibration and noise reduction are put forward. Finally, the low acoustic noise emission of a prototype DAR is verified by measurement.

  3. High benefits approach for electrical energy conversion in electric vehicles from DC to PWM-AC without any generated harmonic

    International Nuclear Information System (INIS)

    Fathabadi, Hassan

    2014-01-01

    Highlights: • Novel hybrid power source including AC feature for using in electric/hybrid vehicles. • Minimizing the energy loss in electric/hybrid vehicles by using the proposed system. • Suitable AC wave form for braking/accelerating purposes in electric/hybrid vehicles. • A novelty is that the harmonic generated by the added AC feature is really zero. • Another novelty is the capability of choosing arbitrary frequency for AC feature. - Abstract: This paper presents a novel hybrid power source, including a Li-ion battery together with an interface, which generates simultaneously electrical energy with the forms of both DC and AC for electric vehicles. A novel and high benefits approach is applied to convert the electrical energy of the Li-ion battery from DC form to single-phase symmetric pulse-width modulation (PWM)-AC form. Harmonic generation is one of the important problems when electrical energy is converted from DC to AC but there are not any generated harmonic during the DC/AC conversion using the proposed technique. The proposed system will be widely used in electric/hybrid vehicles because it has many benefits. Minimizing the energy loss (saving energy), no generated harmonic (it is really zero), the capability of arbitrary/necessary frequency selection for output AC voltage and the ability of long distance energy transmission are some novelties and advantages of the proposed system. The proposed hybrid power source including DC/AC PWM inverter is simulated in Proteus 6 software environment and a laboratory-based prototype of the hybrid power source is constructed to validate the theoretical and simulation results. Simulation and experimental results are presented to prove the superiority of the proposed hybrid power supply

  4. Glycoprotein profiles of macrophages at different stages of activation as revealed by lectin binding after electrophoretic separation.

    Science.gov (United States)

    Irimura, T; North, S M; Nicolson, G L

    1987-01-01

    Glycoprotein profiles of rat macrophages (M phi) at different stages of activation were studied by examining the reactivity of various lectins to the glycoproteins separated by polyacrylamide gel electrophoresis. Ricinus communis agglutinin 1 (RCA1) revealed several components including glycoproteins of Mr 160 kDa and 65 kDa prominent in resident M phi. A pokeweed mitogen (PWM) isolectin, Pa-4, recognizes branched poly(N-acetyllactosamine)-type carbohydrate chains, and revealed a significant increase in glycoproteins of Mr ranging from 70 kDa to 150 kDa on thioglycolate-elicited M phi. Increased reactivity of PWM to thioglycolate-elicited M phi was observed by direct binding of 125I-labeled Pa-4 to intact or glutaraldehyde-fixed M phi. Histochemical staining of formaldehyde-fixed M phi in vitro with biotinylated Pa-4 was consistent with the gel analysis, that is, resident M phi had no reactivity while thioglycolate-elicited M phi showed slight reactivity. Alveolar and intratumoral M phi bound more Pa-4 than resident or thioglycolate-elicited M phi. The PWM isolectin may therefore serve as a marker for an early stage of M phi activation.

  5. Immunological monitoring of patients affected by anaplastic glioma concerning the effects of surgery, radio-, and chemotherapy

    International Nuclear Information System (INIS)

    Servadei, F.; Gaist, G.; Padovani, R.; Parente, R.; Bucci, M.; Spagnolli, F.; Steiner, L.

    1982-01-01

    The authors studied 24 patients affected by anaplastic gliomas as regards immunology. In all of them the authors evaluated the lymphocyte subpopulation (B and T), firstly by simple lymphocyte count, secondly by studying the rosettes E-total and EAC, thirdly by stimulating the lymphocytes with mitogenes phytohaemoagglutinin-P (PHA), concanavalin A (Con A), and poke-weed mitogen (PWM), and lastly by counting the release of Cr 51 in Chang liver cells culture in order to obtain antibody dependent cellular cytotoxicity (ADCC). The parameters were also evaluated after surgery and during conventional radio-chemotherapy with BCNU. Whereas the so-called B-pool seems to be unaffected, the preliminary results show that the T-pool (identified by the E-t rosettes and by responses to PHA, PWM and ConA) is depressed to a statistically significant degree, if compared with a control group. This depression seems to be related to the tumoral mass and it is not increased by radio-chemotherapy. In addition, ADCC also seems to be depressed in our glioma patients in comparison with a control group and with a group of bladder cancer patients. (author)

  6. A Medium-Voltage Motor Drive with a Modular Multilevel PWM Inverter Part I. Experimental Verification by a 400-V, 15-kW Downscaled Model

    Science.gov (United States)

    Hagiwara, Makoto; Nishimura, Kazutoshi; Akagi, Hirofumi

    This paper presents a medium-voltage motor drive with a three-phase modular multilevel PWM inverter and focuses on its control method and operating performance. This motor drive is particularly suitable for fans, blowers, pumps, and compressors, in which the load torque is proportional to the square of the rotating speed. Particular attention is paid to the dc-capacitor voltage fluctuation of each chopper-cell because it may affect the voltage rating of the power switching devices used. This paper describes the theoretical equations related to the amount of the voltage fluctuation. A downscaled model rated at 400V and 15kW is designed and built to confirm the validity and effectiveness of the nine-level (17-level in line-to-line) PWM inverter that is intended for use in medium-voltage motor drives to achieve energy savings.

  7. PWM Carrier Displacement in Multi-N-Phase Drives: An Additional Degree of Freedom to Reduce the DC-Link Stress

    Directory of Open Access Journals (Sweden)

    Michela Diana

    2018-02-01

    Full Text Available The paper presents a particular Pulse Width Modulation (PWM strategy to reduce the (Direct Current DC-link capacitor stress for multi-n-phase drives. A multi-n-phase drive is composed of multiple independent systems of n inverter supplying a multi-n-phase electric machine. The paper focused on the investigation of the best phase shifting between carriers for a triple-3-phase drive compared to the 3-phase counterpart in order to reduce the capacitor bench design point. Simulation and experimental results show as the control technique proposed is able to reduce the value of the DC-link capacitor current in any operating condition including fault case. In this sense, the PWM carrier displacement appears like an additional degree of freedom that can be exploited in multi-n-phase drives but also in multi-motor application.

  8. Parathyroid mitogenic activity in plasma from patients with familial multiple endocrine neoplasia type 1

    International Nuclear Information System (INIS)

    Brandi, M.L.; Aurbach, G.D.; Fitzpatrick, L.A.; Quarto, R.; Spiegel, A.M.; Bliziotes, M.M.; Norton, J.A.; Doppman, J.L.; Marx, S.J.

    1986-01-01

    Hyperplasia of the parathyroid glands is a central feature of familial multiple endocrine neoplasia type 1. We used cultured bovine parathyroid cells to test for mitogenic activity in plasma from patients with this disorder. Normal plasma stimulated [ 3 H]thymidine incorporation, on the average, to the same extent as it was stimulated in a plasma-free control culture. This contrasted with the results of the tests with plasma from patients with familial multiple endocrine neoplasia type 1, in which parathyroid mitogenic activity increased 2400 percent over the control value (P less than 0.001). Plasma from these patients also stimulated the proliferation of bovine parathyroid cells in culture, whereas plasma from normal subjects inhibited it. Parathyroid mitogenic activity in plasma from the patients with familial multiple endocrine neoplasia type 1 was greater than that in plasma from patients with various other disorders, including sporadic primary hyperparathyroidism (with adenoma, hyperplasia, or cancer of the parathyroid), sporadic primary hypergastrinemia, sporadic pituitary tumor, familial hypocalciuric hypercalcemia, and multiple endocrine neoplasia type 2 (P less than 0.05). Parathyroid mitogenic activity in the plasma of patients with familial multiple endocrine neoplasia type 1 persisted for up to four years after total parathyroidectomy. The plasma also had far more mitogenic activity in cultures of parathyroid cells than did optimal concentrations of known growth factors or of any parathyroid secretagogue. This mitogenic activity had an apparent molecular weight of 50,000 to 55,000. We conclude that primary hyperparathyroidism in familial multiple endocrine neoplasia type 1 may have a humoral cause

  9. Stimulated mitogen-activated protein kinase is necessary but not sufficient for the mitogenic response to angiotensin II. A role for phospholipase D.

    Science.gov (United States)

    Wilkie, N; Morton, C; Ng, L L; Boarder, M R

    1996-12-13

    Activation of the mitogen-activated protein kinase (MAPK) cascade has been widely associated with cell proliferation; previous studies have shown that angiotensin II (AII), acting on 7-transmembrane G protein-coupled receptors, stimulates the MAPK pathway. In this report we investigate whether the MAPK pathway is required for the mitogenic response to AII stimulation of vascular smooth muscle cells derived from the hypertensive rat (SHR-VSM). AII stimulates the phosphorylation of MAPK, as determined by Western blot specific for the tyrosine 204 phosphorylated form of the protein. This MAPK phosphorylation was inhibited by the presence of the inhibitor of MAPK kinase activation, PD 098059. Using a peptide kinase assay shown to measure the p42 and p44 isoforms of MAPK, the stimulated response to AII was inhibited by PD 098059 with an IC50 of 15.6 +/- 1.6 microM. The AII stimulation of [3H]thymidine incorporation was inhibited by PD 098059 with an IC50 of 17.8 +/- 3.1 microM. PD 098059 had no effect on AII-stimulated phospholipase C or phospholipase D (PLD) activity. When the SHR-VSM cells were stimulated with phorbol ester, there was an activation of MAPK similar in size and duration to the response to AII, but there was no significant enhancement of [3H]thymidine incorporation. There was also no activation of PLD by phorbol ester, while AII produced a robust PLD response. Diversion of the product of the PLD reaction by 1-butanol caused a partial loss of the [3H]thymidine response; this did not occur with tertiary butanol, which did not interfere with the PLD reaction. These results show that in these cells the MAPK cascade is required but not sufficient for the mitogenic response to AII, and suggest that the full mitogenic response requires both MAPK in conjunction with other signaling components, one of which is PLD.

  10. Tipe Dry Cell dan Wet Cell berdimensi 80 x 80 mm dengan Penambahan PWM E-3 FF (1 kHz

    Directory of Open Access Journals (Sweden)

    Yanur Arzaqa Ghiffari

    2013-09-01

    Full Text Available Ketersediaan bahan bakar minyak semakin terbatas dan hasil pembakarannya berdampak pada pencemaran lingkungan, salah satu solusinya dengan memanfaatkan gas HHO pada kendaraan bermotor. Penelitian dengan sistem direct connection, temperatur mencapai lebih dari 90oC menyebabkan  generator HHO menjadi rusak dan meleleh, maka penelitian ini menambahan alat untuk mengkontrol besarnya arus, frekuensi, dan duty cycle. Pengembangan generator HHO menggunakan tipe kering (dry cell dan tipe basah (wet cell dengan penambahan PWM (Pulse Width Modulation E-3 Fixed Frequency 1 kHz divariasikan berupa duty cycle: 20%, 40%, 60%, 80%  dan direct connection. Pengujian dilakukan di Laboratorium Teknik Pembakaran dan Bahan Bakar - Teknik Mesin ITS.  Dari hasil penelitian didapatkan karakteristik unjuk kerja terbaik pada kedua tipe generator HHO dengan penambahan PWM. Nilai arus dan tegangan lebih stabil dibandingkan dengan tanpa penambahan PWM (direct connection, namun arus cenderung meningkat seiring dengan kenaikan temperatur mencapai 70oC. Efisiensi terbaik pada generator tipe wet dengan duty cycle 80%,  yaitu 27,7 %.

  11. Cyclic AMP counteracts mitogen-induced inositol phosphate generation and increases in intracellular Ca2+ concentrations in human lymphocytes

    NARCIS (Netherlands)

    van Tits, L. J.; Michel, M. C.; Motulsky, H. J.; Maisel, A. S.; Brodde, O. E.

    1991-01-01

    1. The effects of increases in intracellular adenosine 3':5'-cyclic monophosphate (cyclic AMP) on mitogen-induced generation of inositol phosphates and increases in intracellular Ca2+ concentration were investigated in human peripheral blood mononuclear leukocytes (MNL). 2. The mitogens concanavalin

  12. Lack of direct mitogenic activity of dichloroacetate and trichloroacetate in cultured rat hepatocytes

    International Nuclear Information System (INIS)

    Walgren, Jennie L.; Kurtz, David T.; McMillan, JoEllyn M.

    2005-01-01

    Dichloroacetate (DCA) and trichloroacetate (TCA) are hepatocarcinogenic metabolites of the common groundwater contaminant, 1,1,2-trichloroethylene. DCA and TCA have been shown to induce hepatocyte proliferation in vivo, but it is not known if this response is the result of direct mitogenic activity or whether cell replication occurs indirectly in response to tissue injury or inflammation. In this study we used primary cultures of rat hepatocytes, a species susceptible to DCA- but not TCA-induced hepatocarcinogenesis, to determine whether DCA and TCA are direct hepatocyte mitogens. Rat hepatocytes, cultured in growth factor-free medium, were treated with 0.01-1.0 mM DCA or TCA for 10-40 h; cell replication was then assessed by measuring incorporation of 3 H-thymidine into DNA and by cell counts. DCA or TCA treatment did not alter 3 H-thymidine incorporation in the cultured hepatocytes. Although an increase in cell number was not observed, DCA treatment significantly abrogated the normal background cell loss, suggesting an ability to inhibit apoptotic cell death in primary hepatocyte cultures. Furthermore, treatment with DCA synergistically enhanced the mitogenic response to epidermal growth factor. The data indicate that DCA and TCA are not direct mitogens in hepatocyte cultures, which is of interest in view of their ability to stimulate hepatocyte replication in vivo. Nevertheless, the synergistic enhancement of epidermal growth factor-induced hepatocyte replication by DCA is of particular interest and warrants further study

  13. Regulation of mitogen-activated protein kinase 3/1 activity during meiosis resumption in mammals

    Czech Academy of Sciences Publication Activity Database

    Procházka, Radek; Blaha, Milan

    2015-01-01

    Roč. 61, č. 6 (2015), s. 495-502 ISSN 0916-8818 R&D Projects: GA MZe(CZ) QJ1510138 Institutional support: RVO:67985904 Keywords : cumulus oocyte complexes * meiosis resumption * mitogen-activated protein kinase 3/1 (MAPK3/1) Subject RIV: GI - Animal Husbandry ; Breeding Impact factor: 1.453, year: 2015

  14. Mitogen requirement for cell cycle progression in the absence of pocket protein activity

    NARCIS (Netherlands)

    Foijer, Floris; Wolthuis, Rob M F; Doodeman, Valerie; Medema, René H; te Riele, Hein

    2005-01-01

    Primary mouse embryonic fibroblasts lacking expression of all three retinoblastoma protein family members (TKO MEFs) have lost the G1 restriction point. However, in the absence of mitogens these cells become highly sensitive to apoptosis. Here, we show that TKO MEFs that survive serum depletion pass

  15. Insulin resistance enhances the mitogen-activated protein kinase signaling pathway in ovarian granulosa cells.

    Directory of Open Access Journals (Sweden)

    Linghui Kong

    Full Text Available The ovary is the main regulator of female fertility. Granulosa cell dysfunction may be involved in various reproductive endocrine disorders. Here we investigated the effect of insulin resistance on the metabolism and function of ovarian granulosa cells, and dissected the functional status of the mitogen-activated protein kinase signaling pathway in these cells. Our data showed that dexamethasone-induced insulin resistance in mouse granulosa cells reduced insulin sensitivity, accompanied with an increase in phosphorylation of p44/42 mitogen-activated protein kinase. Furthermore, up-regulation of cytochrome P450 subfamily 17 and testosterone and down-regulation of progesterone were observed in insulin-resistant mouse granulosa cells. Inhibition of p44/42 mitogen-activated protein kinase after induction of insulin resistance in mouse granulosa cells decreased phosphorylation of p44/42 mitogen-activated protein kinase, downregulated cytochrome P450 subfamily 17 and lowered progesterone production. This insulin resistance cell model can successfully demonstrate certain mechanisms such as hyperandrogenism, which may inspire a new strategy for treating reproductive endocrine disorders by regulating cell signaling pathways.

  16. PV Power-Generation System with a Phase-Shift PWM Technique for High Step-Up Voltage Applications

    Directory of Open Access Journals (Sweden)

    Cheng-Tao Tsai

    2012-01-01

    Full Text Available A PV power-generation system with a phase-shift pulse-width modulation (PWM technique for high step-up voltage applications is proposed. The proposed power-generation system consists of two stages. In the input stage, all power switches of the full-bridge converter with phase-shift technique can be operated with zero-current switching (ZCS at turn-on or turn-off transition. Hence, the switching losses of the power switches can be reduced. Then, in the DC output stage, a voltage-doubler circuit is used to boost a high dc-link bus voltage. To supply a utility power, a dc/ac inverter is connected to induce a sinusoidal source. In order to draw a maximum power from PV arrays source, a microcontroller is incorporated with the perturbation and observation method to implement maximum power point tracking (MPPT algorithm and power regulating scheme. In this study, a full load power of 300 W prototype has been built. Experimental results are presented to verify the performance and feasibility of the proposed PV power-generation system.

  17. An NPC/H-bridge modular photovoltaic grid connected inverter with new-phase shifted PWM technique

    Energy Technology Data Exchange (ETDEWEB)

    Wanjekeche, T.; Nicolae, D.V.; Jimoh, A.A. [Tshwane Univ. of Technology, Pretoria (South Africa). Dept. of Electrical Engineering

    2010-08-13

    The commonly used topologies for converting direct current power generated by solar panels to high quality alternating current power at the interface to the grid are the high- frequency and line frequency voltage source grid interface system. These topologies utilize transformers which come with negative features such as increase in cost, size and weight of the whole inverter. In addition, the efficiency and reliability of the system is reduced. A novel option for inverters is the multilevel concept as it is based on low frequency switching and provides voltage or current of low sharing between the power semiconductors. The key topologies which have been suggested for multilevel converters are diode clamped or neutral point clamped (NPC); capacitor clamped of flying capacitors (FC); and cascaded H-bridge inverters with separate direct current sources. The cascaded H-bridge converter demonstrates superior qualities among the multilevel converter topologies as a result of its modularity and flexibility. This paper investigated the operating principle of a cascaded NPC/H-bridge inverter for photovoltaic-grid application. The superior characteristics of the model were analyzed using the state space techniques and double Fourier principle. A new and improved phase sifted PWM technique was proposed and its performance was compared. The main system configuration, mathematical modeling, and simulation model were presented. The state space equation showed that the model has 8 different operating modes which can be utilized to realize 5 level voltages per cell. 13 refs., 1 tab., 6 figs.

  18. Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

    Directory of Open Access Journals (Sweden)

    N. Belhaouchet

    2008-03-01

    Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.

  19. A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Fengjun, E-mail: wufengjun@impcas.ac.cn [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Cui, Yuan [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yan, Hongbin [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Zhang, Huajian [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Bin [University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohui [Institute of Modern Physics, CAS, Lanzhou 730000 (China)

    2016-08-01

    To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.

  20. Design and implementation of predictive current control of three-phase PWM rectifier using space-vector modulation (SVM)

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Gaubert, Jean-Paul; Krim, Fateh

    2010-01-01

    This paper is concerned with the design and implementation of current control of three-phase PWM rectifier based on predictive control strategy. The proposed predictive current control technique operates with constant switching frequency, using space-vector modulation (SVM). The main goal of the designed current control scheme is to maintain the dc-bus voltage at the required level and to achieve the unity power factor (UPF) operation of the converter. For this purpose, two predictive current control algorithms, in the sense of deadbeat control, are developed for direct controlling input current vector of the converter in the stationary α-β and rotating d-q reference frame, respectively. For both predictive current control algorithms, at the beginning of each switching period, the required rectifier average voltage vector allowing the cancellation of both tracking errors of current vector components at the end of the switching period, is computed and applied during a predefined switching period by means of SVM. The main advantages of the proposed predictive current control are that no need to use hysteresis comparators or PI controllers in current control loops, and constant switching frequency. Finally, the developed predictive current control algorithms were tested both in simulations and experimentally, and illustrative results are presented here. Results have proven excellent performance in steady and transient states, and verify the validity of the proposed predictive current control which is compared to other control strategies.

  1. Tetrandrine potentiates the glucocorticoid pharmacodynamics via inhibiting P-glycoprotein and mitogen-activated protein kinase in mitogen-activated human peripheral blood mononuclear cells.

    Science.gov (United States)

    Xu, Wencheng; Meng, Kehan; Tu, Yuanchao; Tanaka, Sachiko; Onda, Kenji; Sugiyama, Kentaro; Hirano, Toshihiko; Yamada, Haruki

    2017-07-15

    Glucocorticoids play significant roles in treatments of inflammatory and autoimmune diseases. Some patients show a poor or absent response even to high doses of glucocorticoids. The purpose of this study was to explore whether tetrandrine combined with glucocorticoids could be a new treatment strategy to resolve glucocorticoids resistance. Information on glucocorticoids sensitivity was usually obtained through mitogen-activated human peripheral blood mononuclear cells in cell culture procedures. Thus, human peripheral blood mononuclear cells was chosen as a model to study the immunosuppressive effect of methylprednisolone combined with tetrandrine, including the possible action mechanisms. Tetrandrine decreased the IC 50 value of methylprednisolone significantly, but it showed little toxic effect on the concanavalin A-activated human peripheral blood mononuclear cells. Both tetrandrine and methylprednisolone inhibited the secretion of pro-inflammatory cytokines TNFα and IL-6 significantly and the combination showed stronger inhibitory ability. Tetrandrine and/or methylprednisolone did not increase the percentage of CD4 + CD25 + Foxp3 + regulatory T cells in CD4 + T cells. However tetrandrine with or without methylprednisolone significantly inhibited the function of drug efflux pump P-glycoprotein 170 of CD4 + , CD8 + T cells and lymphocytes. Tetrandrine tended to suppress the phosphorylation of mitogen-activated protein kinase and this effect was potentiated by methylprednisolone. These tetrandrine effects were suggested to be beneficial for improving the immunosuppressive efficacy of glucocorticoids. Glucocorticoids combined with tetrandrine could be a new therapeutic approach to resolve glucocorticoids-resistance possibly via inhibiting the function of P-glycoprotein and blocking mitogen-activated protein kinase signaling pathway from but not affecting on CD4 + CD25 + Foxp3 + regulatory cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. DMPD: Manipulation of mitogen-activated protein kinase/nuclear factor-kappaB-signalingcascades during intracellular Toxoplasma gondii infection. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 15361242 Manipulation of mitogen-activated protein kinase/nuclear factor-kappaB-sig...mmunol Rev. 2004 Oct;201:191-205. (.png) (.svg) (.html) (.csml) Show Manipulation of mitogen-activated protein kinase/nuclear... gondii infection. PubmedID 15361242 Title Manipulation of mitogen-activated protein kinase/nuclear factor-k

  3. Isolated PWM DC-AC SICAM with an active capacitive voltage clamp[Pulse Density Modulated; Pulse Width Modulation

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.

    2004-03-15

    In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)

  4. Relationship between hyperthermic killing and the mitogenic response to serum and growth factors

    International Nuclear Information System (INIS)

    Lin, P.P.; Hahn, G.M.

    1987-01-01

    The possibility that hyperthermic killing involves disruption of the mitogenic response to serum and growth factors was investigated. Subconfluent HA-1 (Chinese Hamster Ovary) cells were made quiescent by 24 hour incubation in serum-free media. Quiescent cells were stimulated with either serum or the growth factors FGF, insulin, and transferrin. DNA synthesis was measured by /sup 3/H-thymidine incorporation. Twenty-four hour incubation in serum-free media did not sensitize HA-1 cells to heat. Survival after 45 0 C heating was similar to survival of exponentially growing cells. The mitogenic response to serum and growth factors was assayed after 45 0 C heating. This correlated well with survival. Preliminary experiments using flow cytometry indicated that clonogenically live cells could be stimulated to progress from G/sub 1/ to G/sub 2/ whereas clonogenically dead (but metabolically alive) cells could not be stimulated

  5. Transcriptional integration of mitogenic and mechanical signals by Myc and YAP.

    Science.gov (United States)

    Croci, Ottavio; De Fazio, Serena; Biagioni, Francesca; Donato, Elisa; Caganova, Marieta; Curti, Laura; Doni, Mirko; Sberna, Silvia; Aldeghi, Deborah; Biancotto, Chiara; Verrecchia, Alessandro; Olivero, Daniela; Amati, Bruno; Campaner, Stefano

    2017-10-15

    Mammalian cells must integrate environmental cues to determine coherent physiological responses. The transcription factors Myc and YAP-TEAD act downstream from mitogenic signals, with the latter responding also to mechanical cues. Here, we show that these factors coordinately regulate genes required for cell proliferation. Activation of Myc led to extensive association with its genomic targets, most of which were prebound by TEAD. At these loci, recruitment of YAP was Myc-dependent and led to full transcriptional activation. This cooperation was critical for cell cycle entry, organ growth, and tumorigenesis. Thus, Myc and YAP-TEAD integrate mitogenic and mechanical cues at the transcriptional level to provide multifactorial control of cell proliferation. © 2017 Croci et al.; Published by Cold Spring Harbor Laboratory Press.

  6. Expression of the superantigen Mycoplasma arthritidis mitogen in Escherichia coli and characterization of the recombinant protein.

    OpenAIRE

    Knudtson, K L; Manohar, M; Joyner, D E; Ahmed, E A; Cole, B C

    1997-01-01

    Mycoplasma arthritidis mitogen (MAM), is a soluble protein with classical superantigenic properties and is produced by an organism that causes an acute and chronic proliferative arthritis. Unfortunately, the process of obtaining purified MAM from M. arthritidis culture supernatants is extremely time-consuming and costly, and very little material is recovered. Thus, our laboratory has expressed MAM in Escherichia coli by using a protein fusion expression system. The construction and expression...

  7. Competing memories of mitogen and p53 signalling control cell-cycle entry.

    Science.gov (United States)

    Yang, Hee Won; Chung, Mingyu; Kudo, Takamasa; Meyer, Tobias

    2017-09-21

    Regulation of cell proliferation is necessary for immune responses, tissue repair, and upkeep of organ function to maintain human health. When proliferating cells complete mitosis, a fraction of newly born daughter cells immediately enter the next cell cycle, while the remaining cells in the same population exit to a transient or persistent quiescent state. Whether this choice between two cell-cycle pathways is due to natural variability in mitogen signalling or other underlying causes is unknown. Here we show that human cells make this fundamental cell-cycle entry or exit decision based on competing memories of variable mitogen and stress signals. Rather than erasing their signalling history at cell-cycle checkpoints before mitosis, mother cells transmit DNA damage-induced p53 protein and mitogen-induced cyclin D1 (CCND1) mRNA to newly born daughter cells. After mitosis, the transferred CCND1 mRNA and p53 protein induce variable expression of cyclin D1 and the CDK inhibitor p21 that almost exclusively determines cell-cycle commitment in daughter cells. We find that stoichiometric inhibition of cyclin D1-CDK4 activity by p21 controls the retinoblastoma (Rb) and E2F transcription program in an ultrasensitive manner. Thus, daughter cells control the proliferation-quiescence decision by converting the memories of variable mitogen and stress signals into a competition between cyclin D1 and p21 expression. We propose a cell-cycle control principle based on natural variation, memory and competition that maximizes the health of growing cell populations.

  8. Mitogenic stimuli and phosphatidylinositol (PI) turnover in cultured 3T3 fibroblasts

    International Nuclear Information System (INIS)

    Kohler, C.; Petersen, R.

    1986-01-01

    The hydrolysis of PI and polyphosphoinositides by phopholipase C is an early and rapid response to cell activation by a variety of neurotransmitters, hormones, growth factors and pharmacological agonists. The authors have examined the role of PI turnover and the generation of second messengers (diacylglycerol and inositol trisphosphate) in the mitogenic response of cultured Balb/c and Swiss 3T3 cells to polypeptide growth factors. Cells were prelabelled with 3 H inositol for 18-20 hours, washed and suspended in Herpes + Li + buffer, and stimulated with platelet-derived growth factor (PDGF), vasopressin, insulin, and other growth factors. PI turnover was measured as the increase in total inositol phosphate (IP) production. IP1, IP2, and IP3 were characterized by sequential elution from a Dowex column. Partially purified PDGF produced a 2-4 fold stimulation of total IP production. This was seen as early as 30 seconds after stimulation and increased for up to 1-2 hours. Balb/c cells were more sensitive than Swiss cells to the mitogenic and PI effects of PDGF. Other mitogenic stimuli had differential effects on PI turnover. Vasopressin (4-400 ng/ml) markedly stimulated PI turnover (3-6 fold) in Swiss, but not Balb/c cells. Insulin (100 ng/ml - 10 μg/ml) increased total IP to a greater degree in Balb/c cells. Epidermal growth factor (10 ng/ml - 10 μg/ml) had no effect on PI turnover and fibroblast growth factor (10 ng/ml - 10 μg/ml) only stimulated at the higher concentrations in Swiss cells. Thrombin (1U/ml - 10 U/ml) produced a 1.5 - 2 fold stimulation in Balb/c cells. Thus, various polypeptide growth factors have differential effects on PI turnover depending on their mitogenic potential and the effector cell type

  9. Activation of mitogen-activated protein kinase by heat shock treatment in Drosophila.

    OpenAIRE

    Chen, F; Torres, M; Duncan, R F

    1995-01-01

    Heat shock treatment of Drosophila melanogaster tissue culture cells causes increased tyrosine phosphorylation of several 44 kDa proteins, which are identified as Drosophila mitogen-activated protein (MAP) kinases. Tyrosine phosphorylation occurs within 5 min, and is maintained at high levels during heat shock. It decreases to basal levels during recovery, concurrent with the repression of heat shock transcription and heat-shock-protein synthesis. The increased MAP kinase tyrosine phosphoryla...

  10. Increased rate of repair of ultraviolet-induced DNA strand breaks in mitogen stimulated lymphocytes

    International Nuclear Information System (INIS)

    Hamlet, S.M.; Lavin, M.F.; Jennings, P.A.; Queensland Univ., St. Lucia; Queensland Univ. St. Lucia

    1982-01-01

    Previous results have shown that phytohaemagglutinin-stimulated bovine lymphocytes exhibit a peak of ultraviolet-induced DNA repair synthesis 3 to 4 days after addition of mitogen. The level of repair synthesis was approximately tenfold higher than that in unstimulated lymphocytes. These studies have been extended to examine the rate of repair of strand breaks in U.V.-irradiated bovine lymphocytes. The extent of breakage of DNA was shown to be the same in mitogen-stimulated and unstimulated lymphocytes from two breeds of cattle, when determined by sedimentation of nucleoids on sucrose gradients. However, in mitogen-stimulated cells the time taken to repair DNA strand breaks was 6 hours compared with 12 hours in stationary phase lymphocytes after a U.V. dose of 5 J/m 2 . These results suggest that the increased rate of repair of strand breaks is due to the induction of enzymes involved at the post-incision stage of DNA repair. Thus the increased level of repair synthesis observed in earlier work correlates with an increased rate of repair of DNA strand breaks in phytohaemagglutinin-stimulated bovine lymphocytes. (author)

  11. Mitogen-activated protein kinases in the porcine retinal arteries and neuroretina following retinal ischemia-reperfusion

    DEFF Research Database (Denmark)

    Gesslein, Bodil; Håkansson, Gisela; Carpio, Ronald

    2010-01-01

    The aim of the present study was to examine changes in the expression of intracellular signal-transduction pathways, specifically mitogen-activated protein kinases, following retinal ischemia-reperfusion....

  12. Implementation of Carrier-Based Simple Boost Pulse Width Modulation (PWM) for Z-Source Inverter (ZSI) using Field Programming Gate Array (FPGA)

    Science.gov (United States)

    Muhammad, M.; Rasin, Z.; Jidin, A.

    2017-08-01

    In recent years, the research on the Z-source inverter (ZSI) has received a wide acceptance due to its attractive solution for example in the renewable energy interface that requires voltage boost capability. The conventional inverter circuit based on the SPWM technique for example does not able to fully utilize its DC input voltage to produce a greater output voltage. The ZSI shoot-through implementation in high switching frequency requires a processor with fast sampling and high precision. In simulation, this can be easily carried out with the available advanced engineering software. In the hardware implementation however, the processor used is not only handle the switching, but also needs to read the data obtained by the sensor, voltage and current control, information display etc. This limits the capacity that can be used to implement the switching fast sampling with high precision. The aims of this work are to implement high precision of carrier-based simple boost PWM for ZSI using FPGA and to verify its real time hardware implementation. The high precision of PWM control algorithm based on the FPGA platform is verified by comparing the simulation results with the experimental results for different modulation index and boost factor, and a good agreement is concluded. It is observed that the application of FPGA reduces complexity, increases speed and the design of the switching technique can be altered without having to modify the hardware implementation.

  13. Assessment of an Average Controller for a DC/DC Converter via Either a PWM or a Sigma-Delta-Modulator

    Directory of Open Access Journals (Sweden)

    R. Silva-Ortigoza

    2014-01-01

    Full Text Available Sliding mode control is a discontinuous control technique that is, by its nature, appropriate for controlling variable structure systems, such as the switch regulated systems employed in power electronics. However, when designing control laws based on the average models of these systems a modulator is necessary for their experimental implementation. Among the most widely used modulators in power electronics are the pulse width modulation (PWM and, more recently, the sigma-delta-modulator (Σ-Δ-modulator. Based on the importance of achieving an appropriate implementation of average control laws and the relevance of the trajectory tracking task in DC/DC power converters, for the first time, this research presents the assessment of the experimental results obtained when one of these controllers is implemented through either a PWM or a Σ-Δ-modulator to perform such a task. A comparative assessment based on the integral square error (ISE index shows that, at frequencies with similar efficiency, the Σ-Δ-modulator provides a better tracking performance for the DC/DC Buck converter. In this paper, an average control based on differential flatness was used to perform the experiments. It is worth mentioning that a different trajectory tracking controller could have been selected for this research.

  14. Design and implementation of high performance direct power control of three-phase PWM rectifier, via fuzzy and PI controller for output voltage regulation

    International Nuclear Information System (INIS)

    Bouafia, Abdelouahab; Krim, Fateh; Gaubert, Jean-Paul

    2009-01-01

    This paper proposes direct power control (DPC) for three-phase PWM rectifiers using a new switching table, without line voltage sensors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The main goal of the control system is to maintain the dc-bus voltage at the required level, while input currents drawn from the power supply should be sinusoidal and in phase with respective phase voltages to satisfy the unity power factor (UPF) operation. Conventional PI and a designed fuzzy logic-based controller, in the dc-bus voltage control loop, have been used to provide active power command. A dSPACE based experimental system was developed to verify the validity of the proposed DPC. The steady-state, and dynamic results illustrating the operation and performance of the proposed control scheme are presented. As a result, it was confirmed that the novel DPC is much better than the classical one. Line currents very close to sinusoidal waveforms (THD < 2%) and good regulation of dc-bus voltage are achieved using PI or fuzzy controller. Moreover, fuzzy logic controller gives excellent performance in transient state, a good rejection of impact load disturbance, and a good robustness

  15. Effect of the serotonin receptor agonist, buspirone, on immune function in HIV-infected individuals: a six-month randomized, double-blind, placebo-controlled trial

    DEFF Research Database (Denmark)

    Eugen-Olsen, Jesper; Benfield, T; Axen, T E

    2000-01-01

    PURPOSE: Previous studies have shown that agents modulating the cAMP/PKA pathway have a beneficial effect on immune reconstitution in HIV-infected individuals. Here we evaluate the effect of buspirone on immune function as measured by CD4 and CD8 T-cell counts, CD4/CD8 T-cell ratio, HIV viral load......, and response to pokeweed mitogen (PWM) in antiretroviral naive HIV-1-infected individuals. METHOD: Twenty-three HIV-infected patients with CD4 T-cell counts above 300 per microL were enrolled in a 6-month double-blinded placebo controlled trial. No patients received antiretroviral therapy during the study...... to placebo-treated patients was observed. There were no significant differences in CD4 T-cell counts, HIV viral load, or proliferative response to PWM between those receiving placebo and those receiving buspirone. CONCLUSION: Buspirone treatment leads to significant changes in CD8 T-cell count and in CD4/CD8...

  16. Functional studies on lymphocytes from two siblings with congential hypogammaglobulinaemia

    International Nuclear Information System (INIS)

    Tauris, P.; Wendelboe Hansen, P.

    1983-01-01

    Two brothers with hypogammaglobulinaemia classified as common variable immunodeficiency (CVID) were investigated for distribution of pheripheral blood lymphocyte (PBL) subpopulations, DNA synthesis and plaque-forming cell (PFC) capability of pokeweed mitogen (PWM) activated autologous and allogenic cocultures. Both patients had a decreased absolute number of T cells and normal or elevated levels of surface immunoglobulin (SmIg) bearing cells. Isolated B cells cocultured with autologous or allogeneic 4000 r irradiated T cells responded subnormally to PWM monitored by the 3 H-thymidine incorporation in microcultures whereas B cells cocultured with allogeneic untreated normal T cells proliferated normally. PBL from parallel macrocultures of unfractionated or T/B separated patients' cells were not able to produce plaques using a reversed haemolytic protein A assay. Addition of glucocorticoid to unfractionated PBL did not reverse the unresponsiveness. In allogeneic cocultures patients' untreated or 2000 r irradiated T cells induced a normal PFC response. Normal untreated T cells induced a reduced number of IgM- and IgG-PFC from patients' B cells but this response was almost eliminated using irradiated normal T cells. These results demonstrate a primary B cell defect in the patients and indicate an impaired cooperation between patients' B and T cells. Activation of patients' B cells to Ig secretion requires the presence of proliferating T cells. (author)

  17. Effects of atomic bomb radiation on differentiation of B lymphocytes and on the function of concanavalin A-induced suppressor T lymphocytes

    International Nuclear Information System (INIS)

    Yamada, Y.; Neriishi, S.; Ishimaru, T.; Shimba, N.; Hamilton, H.B.; Ohgushi, Y.; Koyanagi, M.; Ichimaru, M.

    1985-01-01

    The differentiation of peripheral blood B lymphocytes into immunoglobulin-producing cells (Ig-PC) by pokeweed mitogen (PWM) and the function of concanavalin A (Con A)-induced suppressor T lymphocytes were examined to elucidate the late effects of atomic bomb radiation. A total of 140 individuals, 70 with an exposure dose of 100 rad or more and an equal number with an exposure dose of 0 rad matched by sex and age, were selected from the Nagasaki Adult Health Study (AHS) sample. Both the differentiation of peripheral blood B lymphocytes into Ig-PC by PWM and the function of Con A-induced suppressor T lymphocytes tended to be more depressed in the exposed group than in the control group, but a statistically significant difference could not be observed between the two groups. The function of Con A-induced suppressor T lymphocytes tended to decrease with age, but a statistical significance was detected only for percentage suppression against IgM-PC

  18. A Harmonic Resonance Suppression Strategy for a High-Speed Railway Traction Power Supply System with a SHE-PWM Four-Quadrant Converter Based on Active-Set Secondary Optimization

    Directory of Open Access Journals (Sweden)

    Runze Zhang

    2017-10-01

    Full Text Available Pulse width modulation (PWM technology is widely used in traction converters for high-speed railways. The harmonic distribution caused by PWM is quite extensive, and increases the possibility of grid–train coupling resonance in the traction power supply system (TPSS. This paper first analyzes the mechanism of resonance, when the characteristic harmonic frequency of a four-quadrant converter (4QC current that injects into the traction grid matches the resonant frequency of the traction grid, which may result in resonance in the system. To suppress resonance, this paper adopts specific harmonic elimination–pulse width modulation (SHE-PWM technology combined with a transient direct current control strategy to eliminate the harmonics in the resonant frequency, which may suppress the grid–train coupling resonance. Due to the fact that the SHE-PWM process with multiple switching angles contains complex transcendental equations, the initial value is difficult to provide, and is difficult to solve using ordinary iterative algorithms. In this paper, an active-set secondary optimization method is used to solve the equation. The algorithm has the benefits of low dependence on initial values, fast convergence and high solution accuracy. Finally, the feasibility of the resonant suppression algorithm is verified by means of Matlab simulation.

  19. Systems biology analysis of mitogen activated protein kinase inhibitor resistance in malignant melanoma.

    Science.gov (United States)

    Zecena, Helma; Tveit, Daniel; Wang, Zi; Farhat, Ahmed; Panchal, Parvita; Liu, Jing; Singh, Simar J; Sanghera, Amandeep; Bainiwal, Ajay; Teo, Shuan Y; Meyskens, Frank L; Liu-Smith, Feng; Filipp, Fabian V

    2018-04-04

    Kinase inhibition in the mitogen activated protein kinase (MAPK) pathway is a standard therapy for cancer patients with activating BRAF mutations. However, the anti-tumorigenic effect and clinical benefit are only transient, and tumors are prone to treatment resistance and relapse. To elucidate mechanistic insights into drug resistance, we have established an in vitro cellular model of MAPK inhibitor resistance in malignant melanoma. The cellular model evolved in response to clinical dosage of the BRAF inhibitor, vemurafenib, PLX4032. We conducted transcriptomic expression profiling using RNA-Seq and RT-qPCR arrays. Pathways of melanogenesis, MAPK signaling, cell cycle, and metabolism were significantly enriched among the set of differentially expressed genes of vemurafenib-resistant cells vs control. The underlying mechanism of treatment resistance and pathway rewiring was uncovered to be based on non-genomic adaptation and validated in two distinct melanoma models, SK-MEL-28 and A375. Both cell lines have activating BRAF mutations and display metastatic potential. Downregulation of dual specific phosphatases, tumor suppressors, and negative MAPK regulators reengages mitogenic signaling. Upregulation of growth factors, cytokines, and cognate receptors triggers signaling pathways circumventing BRAF blockage. Further, changes in amino acid and one-carbon metabolism support cellular proliferation despite MAPK inhibitor treatment. In addition, treatment-resistant cells upregulate pigmentation and melanogenesis, pathways which partially overlap with MAPK signaling. Upstream regulator analysis discovered significant perturbation in oncogenic forkhead box and hypoxia inducible factor family transcription factors. The established cellular models offer mechanistic insight into cellular changes and therapeutic targets under inhibitor resistance in malignant melanoma. At a systems biology level, the MAPK pathway undergoes major rewiring while acquiring inhibitor resistance

  20. The effect of midazolam on neutrophil mitogen-activated protein kinase.

    LENUS (Irish Health Repository)

    Ghori, Kamran

    2010-06-01

    Neutrophil p38 mitogen-activated protein kinase (MAPK) is a key enzyme in the intracellular signalling pathway that is responsible for many neutrophil functions, which are important in neutrophil-endothelial interaction. The imidazole compounds are inhibitors of this enzyme system. The objectives of this in-vitro investigation were to examine the effect of midazolam on neutrophil p38 MAPK activation (phosphorylation) following in-vitro ischaemia-reperfusion injury, and the expression of adhesion molecule CD11b\\/CD18.

  1. Asymmetric Carrier Random PWM

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand

    2010-01-01

    index. The flat motor current spectrum generates an acoustical noise close to the white noise, which may improve the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits. The modulation method can be used in open, as well...

  2. Convergence of mitogenic signalling cascades from diverse classes of receptors at the cyclin D-cyclin-dependent kinase-pRb-controlled G1 checkpoint.

    OpenAIRE

    Lukas, J; Bartkova, J; Bartek, J

    1996-01-01

    The commitment of mammalian cells in late G1 to replicate the genome and divide in response to mitogenic growth factors operating via tyrosine kinase receptors depends on phosphorylation of the retinoblastoma protein (pRb), a process controlled by cyclin D-associated cyclin-dependent kinases (cdks) and their inhibitors. This study addressed the issue of whether also other mitogenic signalling cascades require activation of cyclin D-associated kinases or whether any mitogenic pathway can bypas...

  3. Detection and partial purification of a potent mitogenic factor for human thyroid follicular cells.

    Science.gov (United States)

    Bond, J A; Graham, G J; Freshney, M; Dawson, T; Sawhney, N; Williams, E D; Wynford-Thomas, D

    1992-03-01

    Normal adult human thyroid follicular cells have an extremely limited proliferative capacity in vitro. No previously studied mitogen, including thyrotropin (TSH) or epidermal growth factor (EGF), has in our hands resulted in a significant improvement over the 3-4% nuclear [3H]thymidine pulse-labelling index (LI) obtainable with 10% fetal calf serum. Here we report the detection in the conditioned medium from a sub-clone of NIH3T3 fibroblasts of a mitogenic activity capable of increasing this response up to 10-fold, to an LI of over 20%, together with an even greater relative stimulation of mitotic activity. Preliminary characterisation has excluded EGF and TGF alpha, and demonstrated that the activity is bound reversibly by heparin-Sepharose, thus pointing to a member of the heparin-binding fibroblast- or hepatocyte-growth factor families. This material should have wide practical application in facilitating primary culture of follicular cells, and may reveal new mechanisms of stromal-epithelial interaction regulating normal and neoplastic thyroid growth in vivo.

  4. Cellular and Molecular Action of the Mitogenic Protein-Deamidating Toxin from Pasteurella multocida

    Science.gov (United States)

    Wilson, Brenda A.; Ho, Mengfei

    2011-01-01

    Summary The mitogenic toxin from Pasteurella multocida (PMT) is a member of the dermonecrotic toxin family, which includes toxins from Bordetella, E. coli and Yersinia. Members of the dermonecrotic toxin family modulate G-protein targets in host cells through selective deamidation and/or transglutamination of a critical active site glutamine residue in the G-protein target, which results in activation of the intrinsic GTPase activity. Structural and biochemical data point to the uniqueness of PMT among these toxins in its structure and action. Whereas the other dermonecrotic toxins act on small Rho GTPases, PMT acts on the α subunits of heterotrimeric Gq, Gi and G12/13 protein families. To date, experimental evidence support a model whereby PMT potently stimulates various mitogenic and survival pathways through activation of Gq and G12/13 signaling, ultimately leading to cellular proliferation, while strongly inhibiting pathways involved in cellular differentiation through activation of Gi signaling. The resulting cellular outcomes account for the global physiological effects observed during infection with toxinogenic P. multocida, as well as hint at potential long-term sequelae that may result from PMT exposure. PMID:21569202

  5. Comparative studies of mitogen- and antigen-induced lymphocyte proliferation in four captive rhinoceros species.

    Science.gov (United States)

    Vance, Carrie K; Kennedy-Stoskopf, Suzanne; Obringer, Amy R; Roth, Terri L

    2004-12-01

    Cellular immune function in four rhinoceros species was evaluated by way of in vitro lymphocyte proliferation responses to mitogenic and antigenic stimuli to establish normative data on white blood cell activity for each species and to identify species-specific differences that might help explain the predisposition of black rhinoceroses (Diceros bicornis) to disease. A cross section of the U.S. rhinoceros population encompassing all four captive species was sampled, including the Sumatran rhinoceros (Dicerorhinus sumatrensis) (n = 3); Indian rhinoceros (Rhinoceros unicornis) (n = 4); African black rhinoceros (n = 16); and African white rhinoceros (Ceratotherium simum) (n = 10). Of the four species evaluated, African black rhinoceroses exhibited the weakest (P white rhinoceroses, Indian rhinoceroses, and Sumatran rhinoceroses. However, lymphocyte response to bacterial endotoxin lipopolysaccharide was similar (P > 0.05) across species. Antigenic stimulation produced much weaker responses than mitogenic stimulation. No differences (P > 0.05) were observed among rhinoceros species in response to 1 and 10 microg/ml of Leptospira icterohemorrhagiae or Leptospira gryppotyphosa. Lymphocytes from African white rhinoceroses proliferated weakly in the presence of Aspergillus fumigatus filtrate, whereas lymphocytes from the southern black rhinoceros subspecies appeared slightly suppressed in the presence of increasing doses (0.1, 1, and 10 microg/ml) of Aspergillus filtrate. This comparative data set characterizing lymphocyte proliferation in the rhinoceros reveals several differences in immune cell responses among rhinoceros species and provides some evidence that lymphocytes of captive African black rhinoceroses are less vigorous than those of the other rhinoceros species.

  6. Approaches to Suppressing Shaft Voltage in Brushless DC Motor Driven by PWM Inverter Based on Ungrounded Common-Mode Equivalent Circuit

    Science.gov (United States)

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes an ungrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was is small, the reversal of the polarities of the common-mode voltage and shaft voltage is observed. In order to model this reversal, a bridge-type equivalent circuit is proposed. On the basis of calculations and experiment, it is found the values and polarity of the shaft voltage can be are accurately determined with the proposed equivalent circuit. Furthermore, the capacitance value of the insulated rotor required to make the shaft voltage equal to or less than the dielectric breakdown voltage of the bearing grease is obtained.

  7. In vitro metabolic and mitogenic signaling of insulin glargine and its metabolites.

    Directory of Open Access Journals (Sweden)

    Mark R Sommerfeld

    Full Text Available BACKGROUND: Insulin glargine (Lantus is a long-acting basal insulin analog that demonstrates effective day-long glycemic control and a lower incidence of hypoglycemia than NPH insulin. After subcutaneous injection insulin glargine is partly converted into the two main metabolites M1 ([Gly(A21]insulin and M2 ([Gly(A21,des-Thr(B30]insulin. The aim of this study was to characterize the glargine metabolites in vitro with regard to their insulin receptor (IR and IGF-1 receptor (IGF1R binding and signaling properties as well as their metabolic and mitogenic activities. METHODS: The affinity of human insulin, insulin glargine and its metabolites to the IR isoforms A and B or IGF1R was analyzed in a competitive binding assay using SPA technology. Receptor autophosphorylation activities were studied via In-Cell Western in CHO and MEF cells overexpressing human IR-A and IR-B or IGF1R, respectively. The metabolic response of the insulins was studied as stimulation of lipid synthesis using primary rat adipocytes. Thymidine incorporation in Saos-2 cells was used to characterize the mitogenic activity. CONCLUSIONS: The binding of insulin glargine and its metabolites M1 and M2 to the IR were similar and correlated well with their corresponding autophosphorylation and metabolic activities in vitro. No differences were found towards the two IR isoforms A or B. Insulin glargine showed a higher affinity for IGF1R than insulin, resulting in a lower EC(50 value for autophosphorylation of the receptor and a more potent stimulation of thymidine incorporation in Saos-2 cells. In contrast, the metabolites M1 and M2 were significantly less active in binding to and activation of the IGF1R and their mitogenicity in Saos-2 cells was equal to human insulin. These findings strongly support the idea that insulin glargine metabolites contribute with the same potency as insulin glargine to blood glucose control but lead to significantly reduced growth-promoting activity.

  8. Carbohydrate metabolism of lymphocytes: modified methodology and comparisons of diabetics with non-diabetics

    International Nuclear Information System (INIS)

    Glassman, A.B.; Bennett, C.E.

    1980-01-01

    Changes in the hexose monophosphate shunt (HMPS) and Krebs cycle activity during lymphocyte blast transformation are reported in 50 patients with diabetes mellitus and 50 non-diabetics. A modified technique using 12 X 75 mm sterile tubes and micropipette tips stuffed with filter paper was used. The filter paper, soaked with hyamine hydroxide, absorbed radioactively labeled CO 2 produced from [ 14 C]- labeled glucose incorporated by cells. [ 14 C]CO 2 from glucose labeled at the C-1 position measured the activity of the HMPS. [ 14 C]CO 2 from glucose labeled at the C-2 position measured the HMPS activity associated with the feedback of pentose sugars. [ 14 C]-labeled CO 2 from glucose labeled at the C-6 position was used to measure Krebs cycle activity. A statistically significant decrease in HMPS activity was found in diabetic cells exposed to the mitogens phytohemagglutinin-P (PHA-P), concanavalin-A (CON-A) and pokeweed mitogen (PWM) (P<0.01). This decrease in HMPS activity and its relation to lymphocyte blast transformation may be related to the increased incidence of infection known to occur in patients with diabetes mellitus. (Auth.)

  9. Rapamycin Induces Mitogen-activated Protein (MAP) Kinase Phosphatase-1 (MKP-1) Expression through Activation of Protein Kinase B and Mitogen-activated Protein Kinase Kinase Pathways*

    Science.gov (United States)

    Rastogi, Ruchi; Jiang, Zhongliang; Ahmad, Nisar; Rosati, Rita; Liu, Yusen; Beuret, Laurent; Monks, Robert; Charron, Jean; Birnbaum, Morris J.; Samavati, Lobelia

    2013-01-01

    Mitogen-activated protein kinase phosphatase-1 (MKP-1), also known as dual specificity phosphatase-1 (DUSP-1), plays a crucial role in the deactivation of MAPKs. Several drugs with immune-suppressive properties modulate MKP-1 expression as part of their mechanism of action. We investigated the effect of mTOR inhibition through rapamycin and a dual mTOR inhibitor (AZD2014) on MKP-1 expression. Low dose rapamycin led to a rapid activation of both AKT and ERK pathways with a subsequent increase in MKP-1 expression. Rapamycin treatment led to phosphorylation of CREB, transcription factor 1 (ATF1), and ATF2, three transcription factors that bind to the cyclic AMP-responsive elements on the Mkp-1 promoter. Inhibition of either the MEK/ERK or the AKT pathway attenuated rapamycin-mediated MKP-1 induction. AZD2014 did not activate AKT but activated the ERK pathway, leading to a moderate MKP-1 induction. Using bone marrow-derived macrophages (BMDMs) derived from wild-type (WT) mice or mice deficient in AKT1 and AKT2 isoforms or BMDM from targeted deficiency in MEK1 and MEK2, we show that rapamycin treatment led to an increased MKP1 expression in BMDM from WT but failed to do so in BMDMs lacking the AKT1 isoform or MEK1 and MEK2. Importantly, rapamycin pretreatment inhibited LPS-mediated p38 activation and decreased nitric oxide and IL-6 production. Our work provides a conceptual framework for the observed immune modulatory effect of mTOR inhibition. PMID:24126911

  10. Mitogen-activated protein kinase signaling pathways of the tangerine pathotype of Alternaria alternata

    Directory of Open Access Journals (Sweden)

    Kuang-Ren Chung

    2013-06-01

    Full Text Available Mitogen-activated protein kinase (MAPK- mediated signaling pathways have been known to have important functions in eukaryotic organisms. The mechanisms by which the filamentous fungus Alternaria alternata senses and responds to environmental signals have begun to be elucidated. Available data indicate that A. alternata utilizes the Fus3, Hog1 and Slt2 MAPK-mediated signaling pathways, either separately or in a cooperative manner, for conidia formation, resistance to oxidative and osmotic stress, and pathogenesis to citrus. This review provides an overview of our current knowledge of MAPK signaling pathways, in conjunction with the two-component histidine kinase and the Skn7 response regulator, in the tangerine pathotype of A. alternata.

  11. The motogenic and mitogenic responses to HGF are amplified by the Shc adaptor protein

    DEFF Research Database (Denmark)

    Pelicci, G; Giordano, S; Zhen, Z

    1995-01-01

    that phosphotyrosines Y1349VHV and Y1356VNV can work as docking sites for Shc. The Kd of this interaction, measured in real time using synthetic phosphopeptides and recombinant Shc on a BIAcore biosensor, is 150 nm for both sites. After stimulation of the HGF receptor, Shc is phosphorylated on Y317VNV, generating......-type Shc, but not of the Y317-->F mutant, enhances cell migration and growth in response to HGF. These data show that Shc is a relevant substrate of the HGF receptor, and works as an 'amplifier' of the motogenic as well as of the mitogenic response....... an high affinity binding site for Grb2 (Kd = 15 nM). This duplicates the high affinity binding site for Grb2 present on the HGF receptor (Y1356VNV). Thus HGF stimulation can trigger the Ras pathway by recruiting Grb2 both directly through the receptor, and indirectly, through Shc. Overexpression of wild...

  12. Cyclic AMP activates the mitogen-activated protein kinase cascade in PC12 cells

    DEFF Research Database (Denmark)

    Frödin, M; Peraldi, P; Van Obberghen, E

    1994-01-01

    Mitogen-activated protein (MAP) kinases are activated in response to a large variety of extracellular signals, including growth factors, hormones, and neurotransmitters, which activate distinct intracellular signaling pathways. Their activation by the cAMP-dependent pathway, however, has not been...... reported. In rat pheochromocytoma PC12 cells, we demonstrate here a stimulation of the MAP kinase isozyme extracellular signal-regulated kinase 1 (ERK1) following elevation of intracellular cAMP after exposure of the cells to isobutylmethylxanthine, cholera toxin, forskolin, or cAMP-analogues. cAMP acted...... synergistically with phorbol ester, an activator of protein kinase C, in the stimulation of ERK1. In accordance with this observation, the peptide neurotransmitter pituitary adenylate cyclase-activating polypeptide 38 (PACAP38), which stimulates cAMP production as well as phosphatidylinositol breakdown in PC12...

  13. Functional Roles of p38 Mitogen-Activated Protein Kinase in Macrophage-Mediated Inflammatory Responses

    Directory of Open Access Journals (Sweden)

    Yanyan Yang

    2014-01-01

    Full Text Available Inflammation is a natural host defensive process that is largely regulated by macrophages during the innate immune response. Mitogen-activated protein kinases (MAPKs are proline-directed serine and threonine protein kinases that regulate many physiological and pathophysiological cell responses. p38 MAPKs are key MAPKs involved in the production of inflammatory mediators, including tumor necrosis factor-α (TNF-α and cyclooxygenase-2 (COX-2. p38 MAPK signaling plays an essential role in regulating cellular processes, especially inflammation. In this paper, we summarize the characteristics of p38 signaling in macrophage-mediated inflammation. In addition, we discuss the potential of using inhibitors targeting p38 expression in macrophages to treat inflammatory diseases.

  14. Expression of different mitogen-regulated protein/proliferin mRNAs in Ehrlich carcinoma cells.

    Science.gov (United States)

    Gil-Torregrosa, B; Urdiales, J L; Lozano, J; Mates, J M; Sanchez-Jimenez, F

    1994-08-08

    Results from in vivo and from serum-free primary cultures of Ehrlich cells suggest that the expression of mitogen-regulated protein/proliferin (MRP/PLF) mRNAs is not essential for proliferation of this murine tumor. Two sizes for MRP/PRL-related open reading frames (ORFs) have been detected by reverse transcription/PCR amplification. They are almost identical to that reported for PLF-1; but 20% of the amplified cDNA included a shorter ORF, which lacks the entire sequence corresponding to that of the exon 3 of the mrp/plf genes. Ehrlich carcinoma may represent a good model to study regulation of expression and physiological roles of MRP/PLFs in vivo.

  15. A single point mutation changes the crystallization behavior of Mycoplasma arthritidis-derived mitogen

    International Nuclear Information System (INIS)

    Guo, Yi; Li, Zhong; Van Vranken, Sandra J.; Li, Hongmin

    2006-01-01

    The mutagenesis, crystallization and preliminary crystallographic analysis of M. arthritidis-derived mitogen is described. Mycoplasma arthritidis-derived mitogen (MAM) functions as a conventional superantigen (SAg). Although recombinant MAM has been crystallized by the hanging-drop vapour-diffusion method, the crystals diffracted poorly to only 5.0 Å resolution, with large unit-cell parameters a = 163.8, b = 93.0, c = 210.9 Å, β = 93.7° in the monoclinic space group P2 1 . Unit-cell content analysis revealed that as many as 24 molecules could be present in the asymmetric unit. Systematic alanine mutagenesis was applied in order to search for mutants that give crystals of better quality. Two mutants, L50A and K201A, were crystallized under the same conditions as wild-type MAM (MAM wt ). Crystals of the L50A mutant are isomorphous with those of MAM wt , while a new crystal form was obtained for the K201 mutant, belonging to the cubic space group P4 1 32 with unit-cell parameters a = b = c = 181.9 Å. Diffraction data were collected to 3.6 and 2.8 Å resolution from crystals of the MAM L50A and K201A mutants, respectively. Molecular-replacement calculations suggest the presence of two molecules in the asymmetric unit for the MAM K201A mutant crystal, resulting in a V M of 5.0 Å Da −1 and a solvent content of 75%. An interpretable electron-density map for the MAM K201A mutant crystal was produced using the molecular-replacement method

  16. Pentachlorophenol-Induced Cytotoxic, Mitogenic, and Endocrine-Disrupting Activities in Channel Catfish, Ictalurus punctatus

    Directory of Open Access Journals (Sweden)

    Paul B. Tchounwou

    2004-09-01

    Full Text Available Pentachlorophenol (PCP is an organochlorine compound that has been widely used as a biocide in several industrial, agricultural, and domestic applications. Although it has been shown to induce systemic toxicity and carcinogenesis in several experimental studies, the literature is scarce regarding its toxic mechanisms of action at the cellular and molecular levels. Recent investigations in our laboratory have shown that PCP induces cytotoxicity and transcriptionally activates stress genes in human liver carcinoma (HepG2 cells [1]. In this research, we hypothesize that environmental exposure to PCP may trigger cytotoxic, mitogenic, and endocrine-disrupting activities in aquatic organisms including fish. To test this hypothesis, we carried out in vitro cultures of male channel catfish hepatocytes, and performed the fluorescein diacetate assay (FDA to assess for cell viability, and the Western Blot analysis to assess for vitellogenin expression following exposure to PCP. Data obtained from FDA experiments indicated a strong dose-response relationship with respect to PCP cytotoxicity. Upon 48 hrs of exposure, the chemical dose required to cause 50% reduction in cell viability (LD50 was computed to be 1,987.0 + 9.6 μg PCP/mL. The NOAEL and LOAEL were 62.5 + 10.3 μg PCP/mL and 125.0+15.2 μg PCP/mL, respectively. At lower levels of exposure, PCP was found to be mitogenic, showing a strong dose- and time-dependent response with regard to cell proliferation. Western Blot analysis demonstrated the potential of PCP to cause endocrine-disrupting activity, as evidenced by the up regulation of the 125-kDa vitellogenin protein the hepatocytes of male channel catfish.

  17. A glucuronic acid binding leguminous lectin with mitogenic activity toward mouse splenocytes.

    Science.gov (United States)

    Chan, Yau Sang; Wong, Jack Ho; Ng, Tzi Bun

    2011-02-01

    A dimeric 64-kDa lectin was purified from seeds of French bean (Phaseolus vulgaris) cultivar number 1. The purification protocol entailed Q-Sepharose, Affi-gel blue gel, Mono S and Superdex 75. The lectin-enriched fraction was adsorbed on Q-Sepharose and Affi-gel blue gel and desorbed using 1M NaCl in the starting buffer. Hemagglutinating activity was adsorbed on Mono S and eluted with a linear 0.3-1 M NaCl gradient. Gel filtration on Superdex 75 yielded a single absorbance peak which appeared as a single 32-kDa in sodium dodecyl sulfate poylacylamide gel electrophoresis. Full hemagglutinating activity was observed when the lectin was exposed to a pH ranging from 3 to 11. About 50% activity remained at pH 12, and about 25% at pH 0 to pH 2. Activity was totally abolished at pH 13-14. The activity was completely preserved when the ambient temperature was 20 °C-60 °C. However, only 50% and 12.5% of the activity remained at 65 °C and 70 °C, respectively. Activity was barely discernible at 75 °C and completely abrogated at and above 80 °C. Hemagglutinating activity of the lectin was inhibited by glucuronic acid. Maximum mitogenic activity of the lectin toward murine splenocytes occurred at a lectin concentration of 0.488 µM. The mitogenic activity was nearly eliminated in the presence of 250 mM glucuronic acid. The lectin did not exhibit antiproliferative activity toward hepatoma (HepG2) cells, breast cancer (MCF7) cells, and nasopharynegeal carcinoma CNE stage 1 and stage 2 cells. It was also devoid of significant anti-HIV reverse transcriptase activity.

  18. Autoradiographic research on cell proliferation of prenatal rat lung cells and their influence using the mitogen Kallikrein

    International Nuclear Information System (INIS)

    Bock-Lamberlin, P.R.

    1980-01-01

    In this work autoradiographic experiments were carried out on the kinetics of proliferation of four cell populations of the prenatal rat lung with the help of the determination of the 3 H-thymidine marker indices, with the following results: 1. The four studied cell populations exhibited variable proliferation rates on the twentieth or twenty-first day of development. 2. The strongest affect of the exogenously applied mitogen Kallikrein was demonstrated on the vessel wall cells, the next strongest on the bronchial epithelial cells, then the cartilage cells and finally the alveolar wall cells. 3. The mitogenic effect is dependent on dose. Higher doses significantly increased the 3 H-thymidine marker indices of the four cell populations tested in this work. 4. When the exposure time of the Kallikrein was extended by one hour this lead partially to stronger mitogenic effects than by the shorter exposure times at the same and higher dose levels of mitogen. 5. The 3 H-thymidine marker indices are dependent on the exposure time. 6. With increasing litter size, the 3 H indices as a rule decrease. (orig./MG) [de

  19. In vitro, inhibition of mitogen-activated protein kinase pathways protects against bupivacaine- and ropivacaine-induced neurotoxicity

    NARCIS (Netherlands)

    Lirk, Philipp; Haller, Ingrid; Colvin, Hans Peter; Lang, Leopold; Tomaselli, Bettina; Klimaschewski, Lars; Gerner, Peter

    2008-01-01

    Animal models show us that specific activation of the p38 mitogen-activated protein kinase (MAPK) may be a pivotal step in lidocaine neurotoxicity, but this has not been investigated in the case of two very widely used local anesthetics, bupivacaine and ropivacaine. We investigated the hypotheses

  20. The Mitogen-Activated Protein Kinase p38 alpha Regulates Tubular Damage in Murine Anti-Glomerular Basement Membrane Nephritis

    NARCIS (Netherlands)

    Mueller, Ralf; Daniel, Christoph; Hugo, Christian; Amann, Kerstin; Mielenz, Dirk; Endlich, Karlhans; Braun, Tobias; van der Veen, Betty; Heeringa, Peter; Schett, Georg; Zwerina, Jochen

    2013-01-01

    p38 mitogen-activated protein kinase (MAPK) is thought to play a central role in acute and chronic inflammatory responses. Whether p38MAPK plays a pathogenic role in crescentic GN (GN) and which of its four isoforms is preferentially involved in kidney inflammation is not definitely known. We thus

  1. Inhibition of human antigen-induced lymphoblastoid B-cell function by an in vivo-induced suppressor T cell.

    Science.gov (United States)

    Brieva, J A; Stevens, R H

    1983-04-01

    Lymphoblastoid (LB) B cells which spontaneously produce antitetanus toxoid IgG antibodies (Tet-IgG) in short-term cultures (3 days) appear in the circulation 5-7 days after immunization with tetanus toxoid. Addition of pokeweed mitogen (PWM), normally a stimulator of antibody production, caused instead a reduction in the in vitro synthesis of Tet-IgG by the LB cells. In order for this inhibition of antibody production to occur, T cells had to be present, and the inhibition was proportional to the number of T cells added to the culture, demonstrating the existence of PWM-inducible suppressor cells. The cells mediating the suppression had the OKT8 phenotype and also exhibited the following characteristics: (1) a PWM pretreatment period as little as 14 hr was enough to complete activation; (2) conventional inhibitors of suppressor T cells as hydrocortisone and cyclosporin A only partially reversed its effect; and (3) DNA synthesis was not required. The T-suppressor activity was detectable in the circulation before immunization, increased two- to fourfold by 5-12 days after boosting, and waned after 3 weeks. The mechanism of action of this suppression does not appear to involve conventional cytotoxic T cells as (1) the suppression was mediated across allogeneic barriers and (2) the suppression could not be reversed by inclusion of anti-Leu-2a antibodies in the culture. These results suggest that this suppressor T-cell subset may be important in the normal regulation of activated stages of human B lymphocytes.

  2. Surface-expressed insulin receptors as well as IGF-I receptors both contribute to the mitogenic effects of human insulin and its analogues

    DEFF Research Database (Denmark)

    Lundby, Anders; Bolvig, Pernille; Hegelund, Anne Charlotte

    2015-01-01

    There is a medical need for new insulin analogues. Yet, molecular alterations to the insulin molecule can theoretically result in analogues with carcinogenic effects. Preclinical carcinogenicity risk assessment for insulin analogues rests to a large extent on mitogenicity assays in cell lines. We...... therefore optimized mitogenicity assay conditions for a panel of five cell lines. All cell lines expressed insulin receptors (IR), IGF-I receptors (IGF-IR) and hybrid receptors, and in all cell lines, insulin as well as the comparator compounds X10 and IGF-I caused phosphorylation of the IR as well as IGF......-IR. Insulin exhibited mitogenicity EC50 values in the single-digit nanomolar to picomolar range. We observed correlations across cell types between (i) mitogenic potency of insulin and IGF-IR/IR ratio, (ii) Akt phosphorylation and mitogenic potency and (iii) Akt phosphorylation and IR phosphorylation. Using...

  3. Energy optimal control strategies for electro motors; low-cost and sensorless PWM-VSI based induction motor control. Vol. 1: Main report, appendix and annex

    Energy Technology Data Exchange (ETDEWEB)

    Abrahamsen, F.

    1998-02-01

    When variable speed induction motor drives are used in applications that run at low load for long periods, energy can be saved by reducing the motor flux at low load. In this report the efficiency of 2.2 kW standard and high-efficiency motor drives are investigated experimentally with efficiency optimized and constant flux control, with sinusoidal and PWM voltage supply and with varying switching frequency. Steady-state motor models are developed and verified experimentally, and are used to analyze and develop efficiency optimizing control strategies. Four energy optimal control strategies are tested experimentally: cos({phi}) control, model-based control, off-line calculated airgap flux control and stator current/input power minimising search control. Their dynamical properties and their ability to reject load disturbances are analysed. Their ability to save energy is tested on a water pump system. For a typical predefined test-cycle the energy optimal control reduces the energy consumption with 10% compared with classical constant V/Hz control. (au)

  4. A Generation Control of Arbitrary AC Waveforms for the Single-phase Voltage Source PWM Inverter Utilizing an Adaptive Frequency Loss-less Resonator

    Science.gov (United States)

    Hashino, Satoshi; Wada, Keiji; Shimizu, Toshihisa

    Power supplies used on the electric power environment test process for electronic products and audio-amplifiers are required to generate arbitrary ac voltage waveforms in the wide frequency range. Traditionally, analogue amplifier technologies have been used for those application even though those have the disadvantages of low-efficiency, bulky in volume, and heavy in weight. Recently, however, research on the arbitrary waveform power generator becomes to be attractive among power electronics engineers, because the audio amplifiers utilizes the D-Mode switching technologies have been move into the market. This paper presents an arbitrary ac power generator utilizes a novel instantaneous waveform control method for a single-phase voltage source PWM inverter. A remarkable feature of this control method is that an adaptive frequency band-pass filter based on a rotation frame transformation and a command generator on the rotation frame is used. The proposed method can suppress the resonance caused by the LC filter at the output line, and hence it enables to generate a rectangular voltage waveform without overshoot. The command generator generates both an instantaneous frame angle and accurate voltage commands on the rotating frame from one an analogue signal. The effectiveness of this method is verified through 500W experimental set-up.

  5. Development of an On-Line Self-Tuning FPGA-PID-PWM Control Algorithm Design for DC-DC Buck Converter in Mobile Applications

    Directory of Open Access Journals (Sweden)

    Ahmed Sabah Al-Araji

    2017-08-01

    Full Text Available This paper presents a new development of an on-line hybrid self-tuning control algorithm of the Field Programmable Gate Array - Proportional Integral Derivative - Pulse Width Modulation (FPGA-PID-PWM controller for DC-DC buck converter which is used in battery operation of mobile applications. The main goal in this work is to propose structure of the hybrid Bees-PSO tuning control algorithm which has a capability of quickly and precisely searching in the global regions in order to obtain optimal gain parameters for the proposed controller to generate the best voltage control action to achieve the desired performance of the Buck converter output. Matlab simulation results and Xilinx development tool Integrated Software Environment (ISE experimental work show the robustness and effectiveness of the proposed on-line hybrid Bees-PSO tuning control algorithm in terms of obtaining smooth and unsaturated state voltage control action and minimizing the tracking voltage error of the Buck converter output. Moreover, the fitness evaluation number is reduced.

  6. Clinicopathological and prognostic significance of mitogen-activated protein kinases (MAPK) in breast cancers.

    Science.gov (United States)

    Ahmad, Dena A J; Negm, Ola H; Alabdullah, M Layth; Mirza, Sameer; Hamed, Mohamed R; Band, Vimla; Green, Andrew R; Ellis, Ian O; Rakha, Emad A

    2016-10-01

    Mitogen-activated protein kinases (MAPKs) are signalling transduction molecules that have different functions and diverse behaviour in cancer. In breast cancer, MAPK is related to oestrogen receptor (ER) and HER2. Protein expression of a large panel of MAPKs (JNK1/2, ERK, p38, C-JUN and ATF2 including phosphorylated forms) were assessed immunohistochemically in a large (n = 1400) and well-characterised breast cancer series prepared as tissue microarray. Moreover, reverse phase protein array was applied to quantify protein expression of MAPKs in six breast cancer cell lines with different phenotypes including HER2-transfected cells. MAPKs expression was associated with clinicopathological variables characteristic of good prognosis. These associations were most significant in the whole series and in the ER+ subgroup compared to other BC classes. Most of MAPKs showed a positive association with ER, BCL2 and better outcome and were negatively associated with the proliferation marker Ki67 and p53. Association of MAPK with HER2 was mainly seen in the ER- subgroup. Reverse phase protein array confirmed immunohistochemistry results and revealed differential expression of MAPK proteins in ER+ and ER- cell lines. MAPKs are associated with good prognosis and their expression is mainly related to ER. Studying a large panel rather than individual biomarkers may provide improved understanding of the pathway.

  7. Lymphocyte proliferative responses to mitogens in rats having an ancestry of a perinatal iodine-131 insult

    International Nuclear Information System (INIS)

    Stevens, R.H.; Cheng, H.F.

    1987-01-01

    The possible existence of a genealogical memory consisting of altered lymphocyte proliferative responses to a perinatal iodine-131 insult has been investigated in two generations of inbred Fischer F344 rat offspring. The studies which involved exposure to the radioiodine during late pregnancy with concentrations ranging from 1.85 MBq (50 μCi) to 7.4 MBq (200 μCi) revealed that only the peripheral blood T lymphocytes of the first generation male animals were significantly affected. These animals were found to possess T lymphocytes which exhibited increased proliferative responses expressed toward the mitogens concanavalin A and phytohemagglutin; however, no significant changes were noticeable in their B cell population following exposure to lipopolysaccharide. Neither the first generation females nor the male and female offspring of the second generation developed through sibling interbreeding seemed to be affected, this was unlike the cellular, humoral, and natural immunity which had previously been observed to be changed in both the second and third generation animals. These observations suggest that the effects of the radiation insult upon immunocompetency as measured by lymphocyte proliferation do not appear to be inherited

  8. Regulation of WRKY46 transcription factor function by mitogen-activated protein kinases in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Arsheed Hussain Sheikh

    2016-02-01

    Full Text Available AbstractMitogen-activated protein kinase (MAPK cascades are central signalling pathways activated in plants after sensing internal developmental and external stress cues. Knowledge about the downstream substrate proteins of MAPKs is still limited in plants. We screened Arabidopsis WRKY transcription factors as potential targets downstream of MAPKs, and concentrated on characterizing WRKY46 as a substrate of the MAPK, MPK3. Mass spectrometry revealed in vitro phosphorylation of WRKY46 at amino acid position S168 by MPK3. However, mutagenesis studies showed that a second phosphosite, S250, can also be phosphorylated. Elicitation with pathogen-associated molecular patterns (PAMPs, such as the bacterial flagellin-derived flg22 peptide led to in vivo destabilization of WRKY46 in Arabidopsis protoplasts. Mutation of either phosphorylation site reduced the PAMP-induced degradation of WRKY46. Furthermore, the protein for the double phosphosite mutant is expressed at higher levels compared to wild-type proteins or single phosphosite mutants. In line with its nuclear localization and predicted function as a transcriptional activator, overexpression of WRKY46 in protoplasts raised basal plant defence as reflected by the increase in promoter activity of the PAMP-responsive gene, NHL10, in a MAPK-dependent manner. Thus, MAPK-mediated regulation of WRKY46 is a mechanism to control plant defence.

  9. Mitogen-activated protein kinase (MAPK) dynamics determine cell fate in the yeast mating response.

    Science.gov (United States)

    Li, Yang; Roberts, Julie; AkhavanAghdam, Zohreh; Hao, Nan

    2017-12-15

    In the yeast Saccharomyces cerevisiae , the exposure to mating pheromone activates a prototypic mitogen-activated protein kinase (MAPK) cascade and triggers a dose-dependent differentiation response. Whereas a high pheromone dose induces growth arrest and formation of a shmoo-like morphology in yeast cells, lower pheromone doses elicit elongated cell growth. Previous population-level analysis has revealed that the MAPK Fus3 plays an important role in mediating this differentiation switch. To further investigate how Fus3 controls the fate decision process at the single-cell level, we developed a specific translocation-based reporter for monitoring Fus3 activity in individual live cells. Using this reporter, we observed strikingly different dynamic patterns of Fus3 activation in single cells differentiated into distinct fates. Cells committed to growth arrest and shmoo formation exhibited sustained Fus3 activation. In contrast, most cells undergoing elongated growth showed either a delayed gradual increase or pulsatile dynamics of Fus3 activity. Furthermore, we found that chemically perturbing Fus3 dynamics with a specific inhibitor could effectively redirect the mating differentiation, confirming the causative role of Fus3 dynamics in driving cell fate decisions. MAPKs mediate proliferation and differentiation signals in mammals and are therapeutic targets in many cancers. Our results highlight the importance of MAPK dynamics in regulating single-cell responses and open up the possibility that MAPK signaling dynamics could be a pharmacological target in therapeutic interventions. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Mitogen-activated protein kinases interacting kinases are autoinhibited by a reprogrammed activation segment.

    Science.gov (United States)

    Jauch, Ralf; Cho, Min-Kyu; Jäkel, Stefan; Netter, Catharina; Schreiter, Kay; Aicher, Babette; Zweckstetter, Markus; Jäckle, Herbert; Wahl, Markus C

    2006-09-06

    Autoinhibition is a recurring mode of protein kinase regulation and can be based on diverse molecular mechanisms. Here, we show by crystal structure analysis, nuclear magnetic resonance (NMR)-based nucleotide affinity studies and rational mutagenesis that nonphosphorylated mitogen-activated protein (MAP) kinases interacting kinase (Mnk) 1 is autoinhibited by conversion of the activation segment into an autoinhibitory module. In a Mnk1 crystal structure, the activation segment is repositioned via a Mnk-specific sequence insertion at the N-terminal lobe with the following consequences: (i) the peptide substrate binding site is deconstructed, (ii) the interlobal cleft is narrowed, (iii) an essential Lys-Glu pair is disrupted and (iv) the magnesium-binding loop is locked into an ATP-competitive conformation. Consistently, deletion of the Mnk-specific insertion or removal of a conserved phenylalanine side chain, which induces a blockade of the ATP pocket, increase the ATP affinity of Mnk1. Structural rearrangements required for the activation of Mnks are apparent from the cocrystal structure of a Mnk2 D228G -staurosporine complex and can be modeled on the basis of crystal packing interactions. Our data suggest a novel regulatory mechanism specific for the Mnk subfamily.

  11. Sustained mitogen-activated protein kinase activation reprograms defense metabolism and phosphoprotein profile in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Ines eLassowskat

    2014-10-01

    Full Text Available Mitogen-activated protein kinases (MAPKs target a variety of protein substrates to regulate cellular signaling processes in eukaryotes. In plants, the number of identified MAPK substrates that control plant defense responses is still limited. Here, we generated transgenic Arabidopsis thaliana plants with an inducible system to simulate in vivo activation of two stress-activated MAPKs, MPK3 and MPK6. Metabolome analysis revealed that this artificial MPK3/6 activation (without any exposure to pathogens or other stresses is sufficient to drive the production of major defense-related metabolites, including various camalexin, indole glucosinolate and agmatine derivatives. An accompanying (phosphoproteome analysis led to detection of hundreds of potential phosphoproteins downstream of MPK3/6 activation. Besides known MAPK substrates, many candidates on this list possess typical MAPK-targeted phosphosites and in many cases, the corresponding phosphopeptides were detected by mass spectrometry. Notably, several of these putative phosphoproteins have been reported to be associated with the biosynthesis of antimicrobial defense substances (e.g. WRKY transcription factors and proteins encoded by the genes from the PEN pathway required for penetration resistance to filamentous pathogens. Thus, this work provides an inventory of candidate phosphoproteins, including putative direct MAPK substrates, for future analysis of MAPK-mediated defense control. (Proteomics data are available with the identifier PXD001252 via ProteomeXchange, http://proteomecentral.proteomexchange.org.

  12. Review: Mitogen-Activated Protein kinases in nutritional signaling in Arabidopsis

    KAUST Repository

    Chardin, Camille

    2017-04-14

    Mitogen-Activated Protein Kinase (MAPK) cascades are functional modules widespread among eukaryotic organisms. In plants, these modules are encoded by large multigenic families and are involved in many biological processes ranging from stress responses to cellular differentiation and organ development. Furthermore, MAPK pathways are involved in the perception of environmental and physiological modifications. Interestingly, some MAPKs play a role in several signaling networks and could have an integrative function for the response of plants to their environment. In this review, we describe the classification of MAPKs and highlight some of their biochemical actions. We performed an in silico analysis of MAPK gene expression in response to nutrients supporting their involvement in nutritional signaling. While several MAPKs have been identified as players in sugar, nitrogen, phosphate, iron and potassium-related signaling pathways, their biochemical functions are yet mainly unknown. The integration of these regulatory cascades in the current understanding of nutrient signaling is discussed and potential new avenues for approaches toward plants with higher nutrient use efficiencies are evoked.

  13. Effects of the mitogen concanavalin A on pathways of thymocyte energy metabolism.

    Science.gov (United States)

    Krauss, S; Buttgereit, F; Brand, M D

    1999-06-30

    The lectin concanavalin A (Con A) acts as a mitogen that preferentially activates T-cells. It stimulates the energy metabolism of thymocytes within seconds of exposure. We studied short-term effects (<30 min) of Con A on a conceptually simplified model system of rat thymocyte energy metabolism in the concentration range of 0-2 microg Con A per 107 cells, using metabolic control analysis. The model system consisted of three blocks of reactions, linked by the common intermediate mitochondrial membrane potential (Delta[psi]m): the substrate oxidation reactions, which produce the linking intermediate, and the proton conductance (or leak) and ATP turnover pathways which consume Delta[psi]m. Firstly, we used top-down elasticity analysis to establish which subsystems are targeted by Con A. Secondly, we quantitatively analysed the steady-state regulation of the system variables by Con A: how do the subsystem fluxes respond to Con A individually and as a whole? Our results indicate that: (1) steady-state respiration and Delta[psi]m increase as Con A concentration is raised, but at higher concentrations the increase in respiration is less and Delta[psi]m falls; (2) Con A independently changes the kinetics of the reactions that produce and consume Delta[psi]m: the Delta[psi]m-producing reactions are inhibited, and the reactions involved in ATP turnover are stimulated; and (3) the overall effects of Con A are mostly mediated by effects on ATP turnover.

  14. [Activation and cell-aggregation of mononucleus cells after short-term stimulation with mitogen and tuberculin].

    Science.gov (United States)

    Fischnaller, M; Flicker, M; Gerstner, L; Kramer, H; Stockinger, L; Bergmann, K C

    1982-01-01

    The aim of the study was the description of morphological changes in mononukleated cells after short-term stimulation by mitogen and tuberculin visible by light- and electronmicroscopy and in differences between nucleus areas measured by planimetry. Already 1 hr. after p.h.a. stimulation lymphocytes forme clusters in which the mononucleated cells were present mostly as irritated and exhausted cells. In PPD-stimulated lymphocytes clusters were formed after 16 to 24 hrs. These cells were activated. Within clusters strong intercellular contacts were visible using the electron-microscopy. The results of planimetry in regard to nucleus areas of lymphocytes and monocytes were significantly dependent from the kind of mitogen or antigen and the duration of incubation time (analysis of variance).

  15. Inhibition by Isoptin (a calcium antagonist) of the mitogenic stimulation of lymphocytes prior to the S-phase

    International Nuclear Information System (INIS)

    Blitstein-Willinger, E.; Diamantstein, T.

    1978-01-01

    Isoptin (α-isopropyl-α-(N-methyl-N-homoveratryl) -γ-amino-propyl-3,4-dimethoxyphenylacetonitril-hydrochloride) - a calcium antagonist - inhibited mitogenic stimulation of lymphocytes. Isoptin acted prior to the S-phase of the cell cycle but did not prevent the early events involved in triggering of cell mitosis. The drug seems to be a good tool for studying the relevance of the 'early events' assumed to be involved in lymphocyte stimulation. (author)

  16. MEK-1 phosphorylation by MEK kinase, Raf, and mitogen-activated protein kinase: analysis of phosphopeptides and regulation of activity.

    OpenAIRE

    Gardner, A M; Vaillancourt, R R; Lange-Carter, C A; Johnson, G L

    1994-01-01

    MEK-1 is a dual threonine and tyrosine recognition kinase that phosphorylates and activates mitogen-activated protein kinase (MAPK). MEK-1 is in turn activated by phosphorylation. Raf and MAPK/extracellular signal-regulated kinase kinase (MEKK) independently phosphorylate and activate MEK-1. Recombinant MEK-1 is also capable of autoactivation. Purified recombinant wild type MEK-1 and a mutant kinase inactive MEK-1 were used as substrates for MEKK, Raf, and autophosphorylation. MEK-1 phosphory...

  17. Activation and translocation of p38 mitogen-activated protein kinase after stimulation of monocytes with contact sensitizers.

    Science.gov (United States)

    Brand, Pia; Plochmann, Sibylle; Valk, Elke; Zahn, Sabine; Saloga, Joachim; Knop, Jürgen; Becker, Detlef

    2002-07-01

    Recently we described the induction of tyrosine phosphorylation by contact sensitizers as an early molecular event during the activation of antigen- presenting cells. In this study, the role of the p38 mitogen-activated protein kinase for the activation of human monocytes after exposure to four structurally unrelated contact sensitizers was analyzed in comparison with the irritant benzalkonium chloride and an inductor of oxidative stress (H2O2) using immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay techniques. Bio chemical analysis revealed a translocation of p38 from the cytoplasm to the detergent-resistant cell fraction only upon stimulation with contact sensitizers. The activity of p38 was studied by quantification of its phosphorylated active form with a specific antibody and by kinase assay. Although all stimulants used in this study led to the activation of p38, a translocation to the detergent-resistant fraction as well phosphorylation of the mitogen-activated protein kinase dependent transcription factor Elk-1 was induced only by contact sensitizers. Evidence for a functional relevance of mitogen-activated protein kinase activation was provided by measurement of the hapten-induced production of the proinflammatory cytokine interleukin-1beta. Its release was inhibited by blocking p38-mediated signaling using the imidazole compounds SB203580 and SB202190. These data show that contact sensitizers are strong activators of the p38 mitogen-activated protein kinase. Although activation of this stress-associated pathway has been reported for many other stimuli, a unique translocation of p38 from the cytoplasm to the detergent-resistant fraction seems to be a specific event during hapten-induced activation of antigen-presenting cells.

  18. A novel endocrine-disrupting agent in corn with mitogenic activity in human breast and prostatic cancer cells.

    Science.gov (United States)

    Markaverich, Barry; Mani, Shaila; Alejandro, Mary Ann; Mitchell, Andrea; Markaverich, David; Brown, Trellis; Velez-Trippe, Claudia; Murchison, Chris; O'Malley, Bert; Faith, Robert

    2002-01-01

    Housing adult rats on ground corncob bedding impedes male and female mating behavior and causes acyclicity in females. The suppressive effects on ovarian cyclicity are mimicked by a mitogenic agent purified from the ground corncob bedding material (corn mitogen; CM), which stimulates the proliferation of estrogen receptor (ER)-positive (MCF-7 cells) and ER-negative (MDA-MD-231 cells) breast cancer cells. Purified CM does not compete for [(3)H]estradiol binding to ER or nuclear type II sites, and its effects on MCF-7 breast cancer cell proliferation are not blocked by the antiestrogen ICI-182,780. These results suggest that the active component is unlikely to be a phytoestrogen, bioflavonoid, mycotoxin, or other known endocrine-disrupting agent that modifies cell growth via ER or type II [(3)H]estradiol binding sites. CM also stimulates the proliferation of PC-3 human prostatic cancer cells in vitro, and the growth rate of PC-3 cell xenografts is accelerated in nude male mice housed on ground corncob as opposed to pure cellulose bedding. Consequently, this endocrine-disrupting agent in ground corncob bedding may influence behavioral and physiologic reproductive response profiles and malignant cell proliferation in experimental animals. Fresh corn (kernels and cob) or corn tortillas also contain CM, indicating that human exposure is likely; consequently, CM and/or related mitogens in corn products may influence human health and development. PMID:11836146

  19. Replacement of insulin receptor tyrosine residues 1162 and 1163 does not alter the mitogenic effect of the hormone

    International Nuclear Information System (INIS)

    Debant, A.; Clauser, E.; Ponzio, G.; Filloux, C.; Auzan, C.; Contreres, J.O.; Rossi, B.

    1988-01-01

    Chinese hamster ovary transfectants that express insulin receptors in which tyrosine residues 1162 and 1163 were replaced by phenylalanine exhibit a total inhibition of the insulin-mediated tyrosine kinase activity toward exogenous substrates; this latter activity is associated with total inhibition of the hypersensitivity reported for insulin in promoting 2-deoxyglucose uptake. The authors now present evidence that the twin tyrosines also control the insulin-mediated stimulation of glycogen synthesis. Surprisingly, this type of Chinese hamster ovary transfectant is as hypersensitive to insulin for its mitogenic effect as are Chinese hamster ovary cells expressing many intact insulin receptors. Such data suggest that (i) the insulin mitogenic effect routes through a different pathway than insulin uses to activate the transport and metabolism of glucose and (ii) the mitogenic effect of insulin is not controlled by the twin tyrosines. At the molecular level, the solubilized mutated receptor has not insulin-dependent tyrosine kinase activity, whereas this receptor displays measurable insulin-stimulated phosphorylation of its β subunit in 32 P-labeled cells. The authors therefore propose that the autocatalytic phosphorylating activity of the receptor reports a cryptic tyrosine kinase activity that cannot be visualized by the use of classical exogenous substrates

  20. Differential expression of insulin like growth factor I and other fibroblast mitogens in porcine colostrum and milk

    Energy Technology Data Exchange (ETDEWEB)

    Tan, T.J.; Simmen, R.C.M.; Simmen, F.A.

    1987-05-01

    Sow mammary secretions contain at least 3 distinct growth factor activities, distinguished by their size and relative abundance in colostrum or later milk. Gel filtration of colostrum in Sephadex G-200 columns, followed by acid-ethanol extraction and radioimmunoassay (RIA) for insulin like growth factor I (IGF-I) revealed high levels of this factor in the 150K and 50K MW regions, characteristic of IGF-I: binding protein complexes. Acid treatment of these fractions yielded free IGF-I peptide (7.5K). Parallel mitogen assays with a fibroblast cell line (AKR-2B) demonstrated a predominant peak of high MW activity (sow colostral growth factor-I, SCGF-I) eluting near the column void volume (MW > 150K). Treatment of SCGF-I with 1M acetic acid resulted in a size reduction of the mitogenic activity (MW < 10K), suggesting association of SCGF-I with a binding protein. The SCGF-I peptide was noncompetitive in IGF-I RIA, was distinct in MW from free IGF-I, and was not mitogenic for chick embryo fibroblasts. Sow milk contains less IGF-I and SCGF-I but does display a predominant peak of small MW (approx. 3K) AKR-2B activity. The changes in expression of these growth factors during lactation may reflect differing roles in lactogenesis and/or neonatal growth and development.

  1. Pre-ERCP infusion of semapimod, a mitogen-activated protein kinases inhibitor, lowers post-ERCP hyperamylasemia but not pancreatitis incidence

    NARCIS (Netherlands)

    van Westerloo, David J.; Rauws, Erik A.; Hommes, Daan; de Vos, Alex F.; van der Poll, Tom; Powers, Barbara L.; Fockens, Paul; Dijkgraaf, Marcel G. W.; Bruno, Marco J.

    2008-01-01

    BACKGROUND: Acute pancreatitis and hyperamylasemia are frequent complications of an ERCP. Semapimod is a synthetic guanylhydrazone that inhibits the mitogen-activated protein kinase (MAPK) pathway, macrophage activation, and the production of several inflammatory cytokines. OBJECTIVE: This study

  2. Lectins of Erythrina poeppigiana and Erythrina steyermarkii (Leguminosae: characterization and mitogenic effect

    Directory of Open Access Journals (Sweden)

    Silvia Quesada

    1998-12-01

    Full Text Available Erythrina species are widely distributed in Costa Rica and known popularly as "poró". In this study, two species were selected, Erythrina poeppigiana and Erythrina steyermarkii. Seed extracts were prepared in phosphate-buffered saline. The presence of lectins in the extracts was verified by hemagglutinating effect over suspensions of human erythrocytes. A selective hemagglutinating effect on erythrocytes of several mammal species, goat, horse and rabbit red cells was tested; only the latter were agglutinated by E. steyermarkii. The hemagglutinating effect of both lectins was inhibited with the following carbohydrates: D-galactose, N-acetyl galactosamine, D-lactose and D-raffinose. The lectin from E. steyermarkii was also inhibited with L-rhamnose. Both lectins were isolated with gel filtration and affinity chromatography using lactose as ligand. Fractions that proved positive were tested with the sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE. Gel filtration and SDS-PAGE showed that these lectins have an apparent molecular mass of 50kDa, and are formed by two subunits of approximately 25 kDa. E. poeppigiana had no mitogenic effect, but the extract of E. steyermarkii had a mitogenic effect on human mononuclear cells isolated from peripheral blood. The stability of the lectins was tested at different temperature and pH ranges (4 to 100 °C and at pH 2 to 12. Both were stable at a pH range from 2 to 10, and at temperatures from 40 to 70 °C.Las diferentes especies de Erythrina se encuentran ampliamente distribuidas en Costa Rica y se las conoce popularmente con el nombre de "poró". En el presente estudio, se seleccionaron dos especies: Erythrina poeppigiana y Erythrina steyermarkii. Se prepararon extractos de las semillas en solución tampón salina de fosfatos y se verificó la presencia de lectinas en ellos mediante la técnica de hemaglutinación, utilizando eritrocitos humanos. Se trató de demostrar un efecto selectivo

  3. beta. -endorphin modulation of mitogen-stimulated calcium uptake by rat thymocytes

    Energy Technology Data Exchange (ETDEWEB)

    Hemmick, L.M.; Bidlack, J.M.

    1987-10-19

    Lymphocytes stimulated by mitogens or antigens exhibit an enhanced calcium uptake early in the proliferation or activation response. Modulation of this calcium uptake results in alterations of proliferation and immunocompetence. ..beta..-endorphin and other opioids affect several parameters of lymphocyte competence. Limited data are available concerning the mechanism(s) of these effects. This study examines whether a possible opioid mechanism is the modification of the early calcium influx into stimulated lymphocytes. The time course of both concanavalin A (Con A) and phytohemagglutinin (PHA)-stimulated /sup 45/Ca/sup 2 +/ uptake into thymocytes was characterized to determine the optimal time for testing the effects of opioids. BETA-Endorphin 1-31 significantly enhanced Con A-stimulated /sup 45/Ca/sup 2 +/ uptake into rat thymocytes. This peptide had no significant effect on PHA-simulated /sup 45/Ca/sup 2 +/ uptake or on basal thymocyte /sup 45/Ca/sup 2 +/ flux. The ..beta../sub h/-endorphin stimulatory effect was titratable in the range of 0.1 nM to 10 ..mu..M. Naloxone did not reverse the enhancement. Met-enkephalinamide and other opioid agonists did not duplicate the stimulatory effect. Thus, the ..beta../sub h/-endorphin 1-31 enhancement of Con A-stimulated /sup 45/Ca/sup 2 +/ uptake by rat thymocytes does not operate via classical opioid receptor mechanisms. ..beta../sub h/-endorphin 1-31 appears to be acting on a subset of T cells that are responsive to Con A but not to PHA. 30 references, 4 figures, 1 table.

  4. Obesity Increases Mitogen-Activated Protein Kinase Phosphatase-3 Levels in the Hypothalamus of Mice

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    Bárbara de A. Rodrigues

    2017-10-01

    Full Text Available Mitogen-activated Protein Kinase Phosphatase 3 (MKP-3 has been involved in the negative regulation of insulin signaling. The absence of MKP-3 is also associated with reduced adiposity, increased energy expenditure and improved insulin sensitivity. The MKP-3 is known as the main Erk1/2 phosphatase and FoxO1 activator, which has repercussions on the gluconeogenesis pathway and hyperglycemia in obese mice. Recently, we showed that MKP-3 overexpression decreases FoxO1 phosphorylation in the hypothalamus of lean mice. However, the hypothalamic interaction between MKP-3 and FoxO1 during obesity was not investigated yet. Here, the MKP-3 expression and the effects on food intake and energy expenditure, were investigated in high-fat diet-induced obese mice. The results indicate that obesity in mice increased the MKP-3 protein content in the hypothalamus. This hypothalamic upregulation led to an increase of food intake, adiposity, and body weight. Furthermore, the obese mice with increased MKP-3 showed an insulin signaling impairment with reduction of insulin-induced FoxO1 and Erk1/2 phosphorylation in the hypothalamus. Moreover, a bioinformatics analysis of data demonstrated that hypothalamic MKP-3 mRNA levels were positively correlated with body weight and negatively correlated to oxygen consumption (VO2 in BXD mice. Taken together, our study reports that obesity is associated with increased protein levels of hypothalamic MKP-3, which is related to the reduction of FoxO1 and Erk1/2 phosphorylation in the hypothalamus as well as to an increase in body weight and a reduction in energy expenditure.

  5. Noise exposure immediately activates cochlear mitogen-activated protein kinase signaling

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    Kumar N Alagramam

    2014-01-01

    Full Text Available Noise-induced hearing loss (NIHL is a major public health issue worldwide. Uncovering the early molecular events associated with NIHL would reveal mechanisms leading to the hearing loss. Our aim is to investigate the immediate molecular responses after different levels of noise exposure and identify the common and distinct pathways that mediate NIHL. Previous work showed mice exposed to 116 decibels sound pressure level (dB SPL broadband noise for 1 h had greater threshold shifts than the mice exposed to 110 dB SPL broadband noise, hence we used these two noise levels in this study. Groups of 4-8-week-old CBA/CaJ mice were exposed to no noise (control or to broadband noise for 1 h, followed by transcriptome analysis of total cochlear RNA isolated immediately after noise exposure. Previously identified and novel genes were found in all data sets. Following exposure to noise at 116 dB SPL, the earliest responses included up-regulation of 243 genes and down-regulation of 61 genes, while a similar exposure at 110 dB SPL up-regulated 155 genes and down-regulated 221 genes. Bioinformatics analysis indicated that mitogen-activated protein kinase (MAPK signaling was the major pathway in both levels of noise exposure. Nevertheless, both qualitative and quantitative differences were noticed in some MAPK signaling genes, after exposure to different noise levels. Cacna1b , Cacna1g , and Pla2g6 , related to calcium signaling were down-regulated after 110 dB SPL exposure, while the fold increase in the expression of Fos was relatively lower than what was observed after 116 dB SPL exposure. These subtle variations provide insight on the factors that may contribute to the differences in NIHL despite the activation of a common pathway.

  6. Noise exposure immediately activates cochlear mitogen-activated protein kinase signaling.

    Science.gov (United States)

    Alagramam, Kumar N; Stepanyan, Ruben; Jamesdaniel, Samson; Chen, Daniel H-C; Davis, Rickie R

    2014-01-01

    Noise-induced hearing loss (NIHL) is a major public health issue worldwide. Uncovering the early molecular events associated with NIHL would reveal mechanisms leading to the hearing loss. Our aim is to investigate the immediate molecular responses after different levels of noise exposure and identify the common and distinct pathways that mediate NIHL. Previous work showed mice exposed to 116 decibels sound pressure level (dB SPL) broadband noise for 1 h had greater threshold shifts than the mice exposed to 110 dB SPL broadband noise, hence we used these two noise levels in this study. Groups of 4-8-week-old CBA/CaJ mice were exposed to no noise (control) or to broadband noise for 1 h, followed by transcriptome analysis of total cochlear RNA isolated immediately after noise exposure. Previously identified and novel genes were found in all data sets. Following exposure to noise at 116 dB SPL, the earliest responses included up-regulation of 243 genes and down-regulation of 61 genes, while a similar exposure at 110 dB SPL up-regulated 155 genes and down-regulated 221 genes. Bioinformatics analysis indicated that mitogen-activated protein kinase (MAPK) signaling was the major pathway in both levels of noise exposure. Nevertheless, both qualitative and quantitative differences were noticed in some MAPK signaling genes, after exposure to different noise levels. Cacna1b , Cacna1g , and Pla2g6 , related to calcium signaling were down-regulated after 110 dB SPL exposure, while the fold increase in the expression of Fos was relatively lower than what was observed after 116 dB SPL exposure. These subtle variations provide insight on the factors that may contribute to the differences in NIHL despite the activation of a common pathway.

  7. Cyclic nucleotides and mitogen-activated protein kinases: regulation of simvastatin in platelet activation

    Directory of Open Access Journals (Sweden)

    Hou Ssu-Yu

    2010-06-01

    Full Text Available Abstract Background 3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA reductase inhibitors (statins have been widely used to reduce cardiovascular risk. These statins (i.e., simvastatin may exert other effects besides from their cholesterol-lowering actions, including inhibition of platelet activation. Platelet activation is relevant to a variety of coronary heart diseases. Although the inhibitory effect of simvastatin in platelet activation has been studied; the detailed signal transductions by which simvastatin inhibit platelet activation has not yet been completely resolved. Methods The aim of this study was to systematically examine the detailed mechanisms of simvastatin in preventing platelet activation. Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance studies were used to assess the antiplatelet activity of simvastatin. Results Simvastatin (20-50 μM exhibited more-potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists (i.e., thrombin. Simvastatin inhibited collagen-stimulated platelet activation accompanied by [Ca2+]i mobilization, thromboxane A2 (TxA2 formation, and phospholipase C (PLCγ2, protein kinase C (PKC, and mitogen-activated protein kinases (i.e., p38 MAPK, JNKs phosphorylation in washed platelets. Simvastatin obviously increased both cyclic AMP and cyclic GMP levels. Simvastatin markedly increased NO release, vasodilator-stimulated phosphoprotein (VASP phosphorylation, and endothelial nitric oxide synthase (eNOS expression. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the simvastatin-mediated inhibitory effects on platelet aggregation, PLCγ2 and p38 MAPK phosphorylation, and simvastatin-mediated stimulatory effects on VASP and eNOS phosphorylation. Conclusion The most important findings of this study demonstrate for the first time that inhibitory effect of simvastatin in platelet activation may involve activation of the cyclic AMP

  8. Mitogen-Activated Protein Kinase Kinase 3 Regulates Seed Dormancy in Barley.

    Science.gov (United States)

    Nakamura, Shingo; Pourkheirandish, Mohammad; Morishige, Hiromi; Kubo, Yuta; Nakamura, Masako; Ichimura, Kazuya; Seo, Shigemi; Kanamori, Hiroyuki; Wu, Jianzhong; Ando, Tsuyu; Hensel, Goetz; Sameri, Mohammad; Stein, Nils; Sato, Kazuhiro; Matsumoto, Takashi; Yano, Masahiro; Komatsuda, Takao

    2016-03-21

    Seed dormancy has fundamental importance in plant survival and crop production; however, the mechanisms regulating dormancy remain unclear [1-3]. Seed dormancy levels generally decrease during domestication to ensure that crops successfully germinate in the field. However, reduction of seed dormancy can cause devastating losses in cereals like wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.) due to pre-harvest sprouting, the germination of mature seed (grain) on the mother plant when rain occurs before harvest. Understanding the mechanisms of dormancy can facilitate breeding of crop varieties with the appropriate levels of seed dormancy [4-8]. Barley is a model crop [9, 10] and has two major seed dormancy quantitative trait loci (QTLs), SD1 and SD2, on chromosome 5H [11-19]. We detected a QTL designated Qsd2-AK at SD2 as the single major determinant explaining the difference in seed dormancy between the dormant cultivar "Azumamugi" (Az) and the non-dormant cultivar "Kanto Nakate Gold" (KNG). Using map-based cloning, we identified the causal gene for Qsd2-AK as Mitogen-activated Protein Kinase Kinase 3 (MKK3). The dormant Az allele of MKK3 is recessive; the N260T substitution in this allele decreases MKK3 kinase activity and appears to be causal for Qsd2-AK. The N260T substitution occurred in the immediate ancestor allele of the dormant allele, and the established dormant allele became prevalent in barley cultivars grown in East Asia, where the rainy season and harvest season often overlap. Our findings show fine-tuning of seed dormancy during domestication and provide key information for improving pre-harvest sprouting tolerance in barley and wheat. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Cholesterol homeostasis and cell proliferation by mitogenic homologs: insulin, benzo-α-pyrene and UV radiation.

    Science.gov (United States)

    Pandey, Hemlata; Talukdar, Ayantika; Gangte, Jeremy S; Gupta, S Datta; Chandra, N C

    2017-11-03

    Low-Density Lipoprotein (LDL) is known to promote the unregulated proliferation of cells that is progression of cancer. We aimed to investigate the effect of mitogens on the expression of cell cycle proteins, nuclear cholesterol and cell proliferation. We observed that insulin and benzo-α-pyrene (BaP) induced the expression of Low-Density Lipoprotein receptor (LDLR) on HepG2 cells, thereby enhancing the uptake of LDL. The internalized LDL increased the concentration of cholesterol in the cytoplasm and nucleus of the cell. At the same time, insulin and BaP also stimulated the expression of cell cycle proteins viz., Cyclin E and Cdk2, and thus induced more incorporation of Bromodeoxyuridine (BrdU) in cultured cells indicating increased DNA synthesis. Increased expression of cell cycle proteins and DNA synthesis are the indications of DNA replication and new cell synthesis. This suggests a link between the enhanced nuclear cholesterol concentration and new cell formation. On the other hand, UV irradiation with selectively given dose of cell death eventually decreases nuclear cholesterol concentration and LDLR expression. Reduced LDLR shows low functional activity. This, again, repeated the plausibility of the same link between intracellular cholesterol concentration and cell population. The biasness of adverse effect observed by UV irradiation has been compromised by inactivating LDLR with anti-LDLR antibody, resulting in similar effects on Cyclin E expression in the cultured cells. Hence, we concluded that in all the conditions, LDLR expression was found to be a translational event of its transcription factor, SREBP-2, by the induction of insulin, BaP and UV irradiation.

  10. Mitogen activated protein kinases selectively regulate palytoxin-stimulated gene expression in mouse keratinocytes

    International Nuclear Information System (INIS)

    Zeliadt, Nicholette A.; Warmka, Janel K.; Wattenberg, Elizabeth V.

    2003-01-01

    We have been investigating how the novel skin tumor promoter palytoxin transmits signals through mitogen activated protein kinases (MAPKs). Palytoxin activates three major MAPKs, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38, in a keratinocyte cell line derived from initiated mouse skin (308). We previously showed that palytoxin requires ERK to increase matrix metalloproteinase-13 (MMP-13) gene expression, an enzyme implicated in carcinogenesis. Diverse stimuli require JNK and p38 to increase MMP-13 gene expression, however. We therefore used the JNK and p38 inhibitors SP 600125 and SB 202190, respectively, to investigate the role of these MAPKs in palytoxin-induced MMP-13 gene expression. Surprisingly, palytoxin does not require JNK and p38 to increase MMP-13 gene expression. Accordingly, ERK activation, independent of palytoxin and in the absence of JNK and p38 activation, is sufficient to induce MMP-13 gene expression in 308 keratinocytes. Dexamethasone, a synthetic glucocorticoid that inhibits activator protein-1 (AP-1), blocked palytoxin-stimulated MMP-13 gene expression. Therefore, the AP-1 site present in the promoter of the MMP-13 gene appears to be functional and to play a key role in palytoxin-stimulated gene expression. Previous studies showed that palytoxin simulates an ERK-dependent selective increase in the c-Fos content of AP-1 complexes that bind to the promoter of the MMP-13 gene. JNK and p38 can also modulate c-Fos. Palytoxin does not require JNK or p38 to increase c-Fos binding, however. Altogether, these studies indicate that ERK plays a distinctly essential role in transmitting palytoxin-stimulated signals to specific nuclear targets in keratinocytes derived from initiated mouse skin

  11. β-endorphin modulation of mitogen-stimulated calcium uptake by rat thymocytes

    International Nuclear Information System (INIS)

    Hemmick, L.M.; Bidlack, J.M.

    1987-01-01

    Lymphocytes stimulated by mitogens or antigens exhibit an enhanced calcium uptake early in the proliferation or activation response. Modulation of this calcium uptake results in alterations of proliferation and immunocompetence. β-endorphin and other opioids affect several parameters of lymphocyte competence. Limited data are available concerning the mechanism(s) of these effects. This study examines whether a possible opioid mechanism is the modification of the early calcium influx into stimulated lymphocytes. The time course of both concanavalin A (Con A) and phytohemagglutinin (PHA)-stimulated 45 Ca 2+ uptake into thymocytes was characterized to determine the optimal time for testing the effects of opioids. Β-Endorphin 1-31 significantly enhanced Con A-stimulated 45 Ca 2+ uptake into rat thymocytes. This peptide had no significant effect on PHA-simulated 45 Ca 2+ uptake or on basal thymocyte 45 Ca 2+ flux. The β/sub h/-endorphin stimulatory effect was titratable in the range of 0.1 nM to 10 μM. Naloxone did not reverse the enhancement. Met-enkephalinamide and other opioid agonists did not duplicate the stimulatory effect. Thus, the β/sub h/-endorphin 1-31 enhancement of Con A-stimulated 45 Ca 2+ uptake by rat thymocytes does not operate via classical opioid receptor mechanisms. β/sub h/-endorphin 1-31 appears to be acting on a subset of T cells that are responsive to Con A but not to PHA. 30 references, 4 figures, 1 table

  12. Mitogen-Activated Protein Kinase (MAPK) Pathway Regulates Branching by Remodeling Epithelial Cell Adhesion

    Science.gov (United States)

    Ihermann-Hella, Anneliis; Lume, Maria; Miinalainen, Ilkka J.; Pirttiniemi, Anniina; Gui, Yujuan; Peränen, Johan; Charron, Jean; Saarma, Mart; Costantini, Frank; Kuure, Satu

    2014-01-01

    Although the growth factor (GF) signaling guiding renal branching is well characterized, the intracellular cascades mediating GF functions are poorly understood. We studied mitogen-activated protein kinase (MAPK) pathway specifically in the branching epithelia of developing kidney by genetically abrogating the pathway activity in mice lacking simultaneously dual-specificity protein kinases Mek1 and Mek2. Our data show that MAPK pathway is heterogeneously activated in the subset of G1- and S-phase epithelial cells, and its tissue-specific deletion results in severe renal hypodysplasia. Consequently to the deletion of Mek1/2, the activation of ERK1/2 in the epithelium is lost and normal branching pattern in mutant kidneys is substituted with elongation-only phenotype, in which the epithelium is largely unable to form novel branches and complex three-dimensional patterns, but able to grow without primary defects in mitosis. Cellular characterization of double mutant epithelium showed increased E-cadherin at the cell surfaces with its particular accumulation at baso-lateral locations. This indicates changes in cellular adhesion, which were revealed by electron microscopic analysis demonstrating intercellular gaps and increased extracellular space in double mutant epithelium. When challenged to form monolayer cultures, the mutant epithelial cells were impaired in spreading and displayed strong focal adhesions in addition to spiky E-cadherin. Inhibition of MAPK activity reduced paxillin phosphorylation on serine 83 while remnants of phospho-paxillin, together with another focal adhesion (FA) protein vinculin, were augmented at cell surface contacts. We show that MAPK activity is required for branching morphogenesis, and propose that it promotes cell cycle progression and higher cellular motility through remodeling of cellular adhesions. PMID:24603431

  13. Mitogen-activated protein kinase (MAPK pathway regulates branching by remodeling epithelial cell adhesion.

    Directory of Open Access Journals (Sweden)

    Anneliis Ihermann-Hella

    2014-03-01

    Full Text Available Although the growth factor (GF signaling guiding renal branching is well characterized, the intracellular cascades mediating GF functions are poorly understood. We studied mitogen-activated protein kinase (MAPK pathway specifically in the branching epithelia of developing kidney by genetically abrogating the pathway activity in mice lacking simultaneously dual-specificity protein kinases Mek1 and Mek2. Our data show that MAPK pathway is heterogeneously activated in the subset of G1- and S-phase epithelial cells, and its tissue-specific deletion results in severe renal hypodysplasia. Consequently to the deletion of Mek1/2, the activation of ERK1/2 in the epithelium is lost and normal branching pattern in mutant kidneys is substituted with elongation-only phenotype, in which the epithelium is largely unable to form novel branches and complex three-dimensional patterns, but able to grow without primary defects in mitosis. Cellular characterization of double mutant epithelium showed increased E-cadherin at the cell surfaces with its particular accumulation at baso-lateral locations. This indicates changes in cellular adhesion, which were revealed by electron microscopic analysis demonstrating intercellular gaps and increased extracellular space in double mutant epithelium. When challenged to form monolayer cultures, the mutant epithelial cells were impaired in spreading and displayed strong focal adhesions in addition to spiky E-cadherin. Inhibition of MAPK activity reduced paxillin phosphorylation on serine 83 while remnants of phospho-paxillin, together with another focal adhesion (FA protein vinculin, were augmented at cell surface contacts. We show that MAPK activity is required for branching morphogenesis, and propose that it promotes cell cycle progression and higher cellular motility through remodeling of cellular adhesions.

  14. Mitogen-Activated Protein Kinases Mediate Upregulation of Hypothalamic AT1 Receptors in Heart Failure Rats

    Science.gov (United States)

    Wei, Shun-Guang; Yu, Yang; Zhang, Zhi-Hua; Weiss, Robert M.; Felder, Robert B.

    2009-01-01

    In heart failure (HF), angiotensin type-1 receptor (AT1-R) expression is upregulated in brain regions regulating sympathetic drive, blood pressure and body fluid homeostasis. However, the mechanism by which brain AT1-R are upregulated in HF remains unknown. The present study examined the hypothesis that the angiotensin II (ANG II)-triggered mitogen-activated protein kinases (MAPK) p44/42, p38 and c-Jun N-terminal kinase (JNK) contribute to upregulation of the AT1-R in the hypothalamus of rats with HF. AT1-R protein, AT1-R mRNA and AT1-R immunoreactivity increased in the paraventricular nucleus of hypothalamus (PVN) and the subfornical organ (SFO) of rats with ischemia-induced HF, compared with sham-operated controls. Phosphorylated p44/42 MAPK, JNK, and p38 MAPK also increased in PVN and SFO. A 4-week intracerebroventricular (ICV) infusion of the AT1-R antagonist losartan decreased AT1-R protein and phosphorylation of p44/42 MAPK, JNK and p38 MAPK in the HF rats. A 4-week ICV infusion of the p44/42 MAPK inhibitor PD98059 or the JNK inhibitor SP600125 significantly decreased AT1-R protein and AT1-R immunoreactivity in the PVN and SFO, but the p38 MAPK inhibitor SB203580 did not. Treatment with ICV losartan, PD98059 and SP600125 had no effect on AT1-R expression by Western blot in sham-operated rats. In untreated HF rats 4 weeks after coronary ligation, a 3-hour ICV infusion of PD98059, SP600125 or losartan reduced AT1-R mRNA in PVN and SFO. These data indicate that MAPK plays an important role in the upregulation of AT1-R in the rat forebrain in heart failure, and suggest that ANG II upregulates its own receptor by this mechanism. PMID:18768402

  15. Thymic Stromal Lymphopoietin Promotes Fibrosis and Activates Mitogen-Activated Protein Kinases in MRC-5 Cells.

    Science.gov (United States)

    Li, Li; Tang, Su; Tang, Xiaodong

    2016-07-06

    BACKGROUND Acute lung injury (ALI) is a life-threatening hypoxemic respiratory disorder with high incidence and mortality. ALI usually manifests as widespread inflammation and lung fibrosis with the accumulation of pro-inflammatory and pro-fibrotic factors and collagen. Thymic stromal lymphopoietin (TSLP) has a significant role in regulation of inflammation but little is known about its roles in lung fibrosis or ALI. This study aimed to define the role and possible regulatory mechanism of TSLP in lung fibrosis. MATERIAL AND METHODS We cultured human lung fibroblast MRC-5 cells and overexpressed or inhibited TSLP by the vector or small interfering RNA transfection. Then, the pro-fibrotic factors skeletal muscle actin alpha (α-SMA) and collagen I, and the 4 mitogen-activated protein kinases (MAPKs) - MAPK7, p38, extracellular signal-regulated kinase 1 (ERK1), and c-Jun N-terminal kinase 1 (JNK1) - were detected by Western blot. RESULTS Results showed that TSLP promoted the production of α-SMA and collagen I (PMRC-5 cell fibrosis. It also activated the expression of MAPK7, p-p38, p-ERK1, and p-JNK1, but the total MAPK7, p-38, ERK1, and JNK1 protein levels were mostly unchanged, indicating the activated MAPK pathways that might contribute to the promotion of cell fibrosis. CONCLUSIONS This study shows the pro-fibrotic role of TSLP in MRC-5 cells, suggesting TSLP is a potential therapeutic target for treating lung fibrosis in ALI. It possibly functions via activating MAPKs. These findings add to our understanding of the mechanism of fibrosis.

  16. Evolution of insulin-like growth factor-1, prostaglandin E2, and mitogenic activity of bovine mammary primary lymph during the dry period and lactogenesis.

    Science.gov (United States)

    Lacasse, P; Block, E; Turner, J; Woodward, T; Couture, Y; Petitclerc, D

    1996-10-01

    Four pregnant cows near the end of lactation were fitted with a catheter in a lymph duct afferent to the supramammary lymph node. Cows were dried off 3 d after surgery, and samples of lymph were collected daily from the day of surgery until 4 d postpartum. Samples of blood and mammary secretions were taken before and after drying off and at parturition. Concentrations of most metabolites were lower in lymph than in serum. Concentrations of IGF-I and prostaglandin E2 were not affected at drying off but decreased and increased, respectively, at parturition. All IGF-binding proteins that were present in serum were also present in lymph fluid, but the binding activity was lower. Mitogenic activities of lymph samples taken at various physiological stages were determined on mammary epithelial (MAC-T) and fibroblast cell lines. Lymph was mitogenic, but mitogenic activity was not related to physiological stages. The correlation was high between mitogenic activity of lymph on MAC-T cells and the content of prostaglandin E2 in lymph. Supplementation of lymph with additional prostaglandin E2 increased mitogenic activity, and neutralization of lymph by antibodies reduced mitogenic activity. Basal medium conditioned by the epithelial cell line contained 100 to 250 pg/ml of immunoassayable prostaglandin E2.

  17. Diseño y construcción de un inversor monofásico tipo puente con control de frecuencia y modulación de ancho de pulso (pwm)

    OpenAIRE

    Barrera Villacres, Narcisa De Jesus; Chong Aguirre, Pedro; Villagomez Gavilanes, Yary Justo; Chootong Ching, Norman

    2009-01-01

    El trabajo a desarrollarse en este tópico consiste en el diseño de un inversor monofásico de frecuencia variable y modulación de ancho de pulso o PWM, lo que significa que se puede variar el ancho del pulso alterno producido. Esto es un convertidor de potencia dc a potencia ac con la posibilidad de variar la frecuencia dentro de un amplio rango de trabajo. Se ha diseñado con la capacidad de que la carga no afecte el funcionamiento del inversor (como cuando se introduce una carga inductiva). ...

  18. Changes in resting mitogen-activated protein kinases following resistance exercise overreaching and overtraining.

    Science.gov (United States)

    Nicoll, Justin X; Fry, Andrew C; Galpin, Andrew J; Sterczala, Adam J; Thomason, Donald B; Moore, Christopher A; Weiss, Lawrence W; Chiu, Loren Z F

    2016-12-01

    Many physiological maladaptations persist after overreaching and overtraining resistance exercise (RE). However, no studies have investigated changes in mitogen-activated protein kinases (MAPK) after overtraining in humans, despite their critical role regulating exercise-induced muscular adaptations. The purpose of this study was to describe the changes in total and resting phosphorylation status of extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun NH 2 -terminal kinase (JNK) and p38-MAPK following a period of RE overreaching or overtraining. Following 2-4 weeks of normal training (low volume/low intensity), two groups of males performed either a high-power overreaching protocol (HPOR n = 6, mean ± SD, age 23 ± 3.4 years, mass 86.5 ± 17.7 kg, height 1.77 ± 0.06 m) or high-intensity overtraining protocol (HIOT n = 8, age 19.8 ± 1.8 years, mass 76.8 ± 6.7 kg, height 1.8 ± 0.06 m). Resting muscle biopsies were obtained at baseline (BL; end of normal training period) and 24 h after the final session of stressful training (i.e., HPOR or HIOT programs). Total MAPK and ratio of phosphorylated/total (p-MAPK)- ERK1/2, JNK, and p38-MAPK were analyzed via western blotting. 2 × 2 (group × time) ANOVA determined differences in MAPK between BL and post-training protocols. Compared to BL, total-ERK increased after HPOR, but decreased after HIOT (p ≤ 0.05). p-ERK1/2/total-ERK increased after HIOT (p ≤ 0.05). The ratio of p-JNK/total-JNK and p-ERK1/2/total-ERK decreased after HPOR (p ≤ 0.05); however, this result was primarily due to increased total MAPK content. p-p38-MAPK decreased after HPOR (p ≤ 0.05). Total and p-MAPK are differentially expressed after HPOR and HIOT RE. These changes are likely involved in the maladaptation reported in overreaching and overtraining exercise. This is the first study describing altered MAPK in RE overtrained and overreached humans.

  19. Overexpression of Populus trichocarpa Mitogen-Activated Protein Kinase Kinase4 Enhances Salt Tolerance in Tobacco

    Directory of Open Access Journals (Sweden)

    Chengjun Yang

    2017-10-01

    Full Text Available Mitogen-activated protein kinase (MAPK is one of the factors of cascade reactions affecting responses to signal pathway of environmental stimuli. Throughout the life of plants, MAPK family members participate in signal transduction pathways and regulate various intracellular physiological and metabolic reactions. To gain insights into regulatory function of MAPK kinase (MAPKK in Populus trichocarpa under salt stress, we obtained full-length cDNA of PtMAPKK4 and analyzed different expression levels of PtMAPKK4 gene in leaves, stems, and root organs. The relationship between PtMAPKK4 and salt stress was studied by detecting expression characteristics of mRNA under 150 mM NaCl stress using real-time quantitative polymerase chain reaction. The results showed that expression of PtMAPKK4 increased under salt (NaCl stress in leaves but initially reduced and then increased in roots. Thus, salt stress failed to induce PtMAPKK4 expression in stems. PtMAPKK4 possibly participates in regulation of plant growth and metabolism, thereby improving its salt tolerance. We used Saccharomyces cerevisiae strain INVScI to verify subcellular localization of PtMAPKK4 kinase. The yeast strains containing pYES2-PtMAPKK4-GFP plasmid expressed GFP fusion proteins under the induction of d-galactose, and the products were located in nucleus. These results were consistent with network prediction and confirmed location of PtMAPKK4 enzyme in the nucleus. We tested NaCl tolerance in transgenic tobacco lines overexpressing PtMAPKK4 under the control of 35S promoter at germination stage to detect salt tolerance function of PtMAPKK4. Compared withK326 (a wild-type tobacco, lines overexpressing PtMAPKK4 showed a certain degree of improvement in tolerance, germination, and growth. NaCl inhibited growth of overexpressed line and K326 at the seedling stage. However, statistical analysis showed longer root length, higher fresh weight, and lower MDA content in transgenic lines in

  20. Catalytic reaction pathway for the mitogen-activated protein kinase ERK2.

    Science.gov (United States)

    Prowse, C N; Hagopian, J C; Cobb, M H; Ahn, N G; Lew, J

    2000-05-23

    The structural, functional, and regulatory properties of the mitogen-activated protein kinases (MAP kinases) have long attracted considerable attention owing to the critical role that these enzymes play in signal transduction. While several MAP kinase X-ray crystal structures currently exist, there is by comparison little mechanistic information available to correlate the structural data with the known biochemical properties of these molecules. We have employed steady-state kinetic and solvent viscosometric techniques to characterize the catalytic reaction pathway of the MAP kinase ERK2 with respect to the phosphorylation of a protein substrate, myelin basic protein (MBP), and a synthetic peptide substrate, ERKtide. A minor viscosity effect on k(cat) with respect to the phosphorylation of MBP was observed (k(cat) = 10 +/- 2 s(-1), k(cat)(eta) = 0.18 +/- 0.05), indicating that substrate processing occurs via slow phosphoryl group transfer (12 +/- 4 s(-1)) followed by the faster release of products (56 +/- 4 s(-1)). At an MBP concentration extrapolated to infinity, no significant viscosity effect on k(cat)/K(m(ATP)) was observed (k(cat)/K(m(ATP)) = 0.2 +/- 0.1 microM(-1) s(-1), k(cat)/K(m(ATP))(eta) = -0.08 +/- 0.04), consistent with rapid-equilibrium binding of the nucleotide. In contrast, at saturating ATP, a full viscosity effect on k(cat)/K(m) for MBP was apparent (k(cat)/K(m(MBP)) = 2.4 +/- 1 microM(-1) s(-1), k(cat)/K(m(MBP))(eta) = 1.0 +/- 0.1), while no viscosity effect was observed on k(cat)/K(m) for the phosphorylation of ERKtide (k(cat)/K(m(ERKtide)) = (4 +/- 2) x 10(-3) microM(-1) s(-1), k(cat)/K(m(ERKtide))(eta) = -0.02 +/- 0.02). This is consistent with the diffusion-limited binding of MBP, in contrast to the rapid-equilibrium binding of ERKtide, to form the ternary Michaelis complex. Calculated values for binding constants show that the estimated value for K(d(MBP)) (/= 1.5 mM). The dramatically higher catalytic efficiency of MBP in comparison to that

  1. Convergence of mitogenic signalling cascades from diverse classes of receptors at the cyclin D-cyclin-dependent kinase-pRb-controlled G1 checkpoint.

    Science.gov (United States)

    Lukas, J; Bartkova, J; Bartek, J

    1996-12-01

    The commitment of mammalian cells in late G1 to replicate the genome and divide in response to mitogenic growth factors operating via tyrosine kinase receptors depends on phosphorylation of the retinoblastoma protein (pRb), a process controlled by cyclin D-associated cyclin-dependent kinases (cdks) and their inhibitors. This study addressed the issue of whether also other mitogenic signalling cascades require activation of cyclin D-associated kinases or whether any mitogenic pathway can bypass the cyclin D-pRb checkpoint. We show that mitogenic signal transduction pathways from three classes of receptors, the membrane tyrosine kinase receptors activated by serum mitogens or epidermal growth factor, estrogen receptors triggered by estradiol, and the cyclic AMP-dependent signalling from G-protein-coupled thyrotropin receptors, all converge and strictly require the cyclin D-cdk activity to induce S phase in human MCF-7 cells and/or primary dog thyrocytes. Combined microinjection and biochemical approaches showed that whereas these three mitogenic cascades are sensitive to the p16 inhibitor of cdk4/6 and/or cyclin D1-neutralizing antibody and able to induce pRb kinase activity, their upstream biochemical routes are distinct as demonstrated by their differential sensitivity to lovastatin and requirements for mitogen-activated protein kinases whose sustained activation is seen only in the growth factor-dependent pathway. Taken together, these results support the candidacy of the cyclin D-cdk-pRb interplay for the convergence step of multiple signalling cascades and a mechanism contributing to the restriction point switch.

  2. Studies on binding and mitogenic effect of insulin and insulin-like growth factor I in glomerular mesangial cells

    International Nuclear Information System (INIS)

    Conti, F.G.; Striker, L.J.; Lesniak, M.A.; MacKay, K.; Roth, J.; Striker, G.E.

    1988-01-01

    The mesangial cells are actively involved in regulating glomerular hemodynamics. Their overlying endothelium is fenestrated; therefore, these cells are directly exposed to plasma substances, including hormones such as insulin and insulin-like growth factor I (IGF-I). These peptides may contribute to the mesangial sclerosis and cellular hyperplasia that characterize diabetic glomerulopathy. We report herein the characterization of the receptors and the mitogenic effects of IGF-I and insulin on mouse glomerular mesangial cells in culture. The IGF-I receptor was characterized on intact cells. The Kd of the IGF-I receptor was 1.47 X 10(-9) M, and the estimated number of sites was 64,000 receptors/cell. The binding was time, temperature, and pH dependent, and the receptor showed down-regulation after exposure to serum. The expression of the receptor did not change on cells at different densities. The specific binding for insulin was too low to allow characterization of the insulin receptor on intact cells. However, it was possible to identify the insulin receptor in a wheat germ agglutinin-purified preparation of solubilized mesangial cells. This receptor showed the characteristic features of the insulin receptor, including pH dependence of binding and a curvilinear Scatchard plot. The mitogenic effects of insulin and IGF-I on mesangial cells were measured by the incorporation of [3H]thymidine into DNA. IGF-I was more potent than insulin. The half-maximal response to IGF-I stimulation occurred at 1.3 X 10(-10) M, and a similar increase with insulin was observed at concentrations in the range of 10(-7) M, suggesting that this insulin action was mediated through the IGF-I receptor. These data show that the mouse microvascular smooth muscle cells of the glomerulus express a cell surface receptor for IGF-I in vitro and that this peptide is a potent mitogen for these mesangial cells

  3. Contribution of Each of Four Superantigens to Streptococcus equi-Induced Mitogenicity, Gamma Interferon Synthesis, and Immunity ▿

    Science.gov (United States)

    Paillot, Romain; Robinson, Carl; Steward, Karen; Wright, Nicola; Jourdan, Thibaud; Butcher, Nicola; Heather, Zoe; Waller, Andrew S.

    2010-01-01

    Streptococcus equi is the causative agent of strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to characterize the contribution of each of these S. equi sAgs to mitogenic activity in vitro and quantify the sAg-neutralizing capacity of sera from naturally infected horses in order to better understand their role in pathogenicity. Each of the sAgs was successfully cloned, and soluble proteins were produced in Escherichia coli. SeeI, SeeL, and SeeM induced a dose-dependent proliferative response in equine CD4 T lymphocytes and synthesis of gamma interferon (IFN-γ). SeeH did not stimulate equine peripheral blood mononuclear cells (PBMC) but induced proliferation of asinine PBMC. Allelic replacement mutants of S. equi strain 4047 with sequential deletion of the superantigen genes were generated. Deletion of seeI, seeL, and seeM completely abrogated the mitogenic activity and synthesis of IFN-γ, in equine PBMC, of the strain 4047 culture supernatant. Sera from naturally infected convalescent horses had only limited sAg-neutralizing activities. We propose that S. equi sAgs play an important role in S. equi pathogenicity by stimulating an overzealous and inappropriate Th1 response that may interfere with the development of an effective immune response. PMID:20123710

  4. Contribution of each of four Superantigens to Streptococcus equi-induced mitogenicity, gamma interferon synthesis, and immunity.

    Science.gov (United States)

    Paillot, Romain; Robinson, Carl; Steward, Karen; Wright, Nicola; Jourdan, Thibaud; Butcher, Nicola; Heather, Zoe; Waller, Andrew S

    2010-04-01

    Streptococcus equi is the causative agent of strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to characterize the contribution of each of these S. equi sAgs to mitogenic activity in vitro and quantify the sAg-neutralizing capacity of sera from naturally infected horses in order to better understand their role in pathogenicity. Each of the sAgs was successfully cloned, and soluble proteins were produced in Escherichia coli. SeeI, SeeL, and SeeM induced a dose-dependent proliferative response in equine CD4 T lymphocytes and synthesis of gamma interferon (IFN-gamma). SeeH did not stimulate equine peripheral blood mononuclear cells (PBMC) but induced proliferation of asinine PBMC. Allelic replacement mutants of S. equi strain 4047 with sequential deletion of the superantigen genes were generated. Deletion of seeI, seeL, and seeM completely abrogated the mitogenic activity and synthesis of IFN-gamma, in equine PBMC, of the strain 4047 culture supernatant. Sera from naturally infected convalescent horses had only limited sAg-neutralizing activities. We propose that S. equi sAgs play an important role in S. equi pathogenicity by stimulating an overzealous and inappropriate Th1 response that may interfere with the development of an effective immune response.

  5. Contribution of Each of Four Superantigens to Streptococcus equi-Induced Mitogenicity, Gamma Interferon Synthesis, and Immunity ▿

    OpenAIRE

    Paillot, Romain; Robinson, Carl; Steward, Karen; Wright, Nicola; Jourdan, Thibaud; Butcher, Nicola; Heather, Zoe; Waller, Andrew S.

    2010-01-01

    Streptococcus equi is the causative agent of strangles, the most frequently diagnosed infectious disease of horses worldwide. The disease is characterized by abscessation and swelling of the lymph nodes of the head and neck, which can literally strangle the horse to death. S. equi produces four recently acquired phage-associated bacterial superantigens (sAgs; SeeH, SeeI, SeeL, and SeeM) that share homology with the mitogenic toxins of Streptococcus pyogenes. The aim of this study was to chara...

  6. Ligand binding affinity at the insulin receptor isoform A (IR-A and subsequent IR-A tyrosine phosphorylation kinetics are important determinants of mitogenic biological outcomes.

    Directory of Open Access Journals (Sweden)

    Harinda eRajapaksha

    2015-07-01

    Full Text Available The insulin receptor (IR is a tyrosine kinase receptor that can mediate both metabolic and mitogenic biological actions. The IR isoform-A (IR-A arises from alternative splicing of exon 11 and has different ligand binding and signalling properties compared to the IR isoform-B. The IR-A not only binds insulin but also insulin-like growth factor-II (IGF-II with high affinity. IGF-II acting through the IR-A promotes cancer cell proliferation, survival and migration by activating some unique signalling molecules compared to those activated by insulin. This observation led us to investigate whether the different IR-A signalling outcomes in response to IGF-II and insulin could be attributed to phosphorylation of a different subset of IR-A tyrosine residues or to the phosphorylation kinetics. We correlated IR-A phosphorylation to activation of molecules involved in mitogenic and metabolic signalling (MAPK and Akt and receptor internalisation rates (related to mitogenic signalling. We also extended this study to incorporate two ligands that are known to promote predominantly mitogenic ([His4, Tyr15, Thr49, Ile51] IGF-I, qIGF-I or metabolic (S597 peptide biological actions, to see if common mechanisms can be used to define mitogenic or metabolic signalling through the IR-A. The 3-fold lower mitogenic action of IGF-II compared to insulin was associated with a decreased potency in activation of Y960, Y1146, Y1150, Y1151, Y1316 and Y1322, in MAPK phosphorylation and in IR-A internalization. With the poorly mitogenic S597 peptide it was a decreased rate of tyrosine phosphorylation rather than potency that was associated with a low mitogenic potential. We conclude that both decreased affinity of IR-A binding and the kinetics of IR-A phosphorylation can independently lead to a lower mitogenic activity. None of the studied parameters could account for the lower metabolic activity of qIGF-I.

  7. Diseño asistido por computadora del patrón de encendido en inversores de tensión, utilizando la técnica de control PWM

    Directory of Open Access Journals (Sweden)

    Elio Castro Alfonso

    2011-03-01

    Full Text Available El artículo se relaciona con el desarrollo de un programa de ayuda para el diseño de los patrones de control deinversores de potencia tipo puente que utilizan técnicas PWM (Pulse Width Modulation. Este método de controlbien establecido, permite incorporar todas las funciones del inversor, pero en lo fundamental garantizar la regulaciónde la tensión de salida manteniendo el factor de distorsión de armónicos lo suficientemente bajo (3-5 % comopara ser tolerado por los consumidores usuales. Obtener un adecuado diseño del patrón de tablas de búsquedapara su utilización en un inversor real empleando microcontrolador, es el problema fundamental a resolver. Losresultados del trabajo han sido comprobados con la ayuda de un procesador 8031.  This paper is related with a program which calculates the control pattern of single-phase power inverters usingPWM techniques.This kind of control if it's well established makes possible to incorporate not all the inverterfunctions,but mainly the voltage regulation by keeping the total harmonics distorsion as low as possible (3-5%;quite good for any consumer.The main problem to solve is to get a proper design of the tables search pattern tobe used in a real single-phase inverter control using any processor.The experimental work has been done usingthe 8031 microcontroller.

  8. Systemic immune dysfunction in pancreatic cancer patients.

    Science.gov (United States)

    Poch, Bertram; Lotspeich, Errki; Ramadani, Marco; Gansauge, Susanne; Beger, Hans G; Gansauge, Frank

    2007-05-01

    We investigated the immune status in 32 pancreatic cancer patients (PC) in comparison with healthy controls (HC). Using flow cytometry, peripheral blood lymphocytes (PBL) were characterized by the expression of surface markers for T helper cells (CD4), T suppressor cells (CD8), B cells (CD19) and NK cells (CD56). The blastogenic response of PBL was analyzed after stimulation with concavalin A (ConA), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and anti-CD3 antibodies. The serum levels of TNF-alpha, IL-1beta, IL-2, IL-10, IL-12, IL-18, IL-1RA, sIL-2R and TGF-beta were determined by ELISA. No differences in the distribution of peripheral immunocytes in PC were found, whereas the blastogenic response of peripheral blood lymphocytes (PBL) after stimulation with PHA or anti-CD3 antibodies was significantly decreased in PC. In PC, we found reduced serum levels of IL-2 and significantly elevated levels of TNF-alpha, TGF-beta1, IL-10, IL-2R, IL-1beta and IL-1RA. These data provide evidence for a systemic immune dysfunction in pancreatic cancer patients characterized by a shift towards a T helper cell type 2 cytokine profile, a significant elevation of substances related to T cell suppression and a reduced blastogenic response to PHA and anti-CD3 antibodies of PBL.

  9. Potassium humate inhibits complement activation and the production of inflammatory cytokines in vitro

    Energy Technology Data Exchange (ETDEWEB)

    van Rensburg, C.E.J.; Naude, P.J. [University of Pretoria, Pretoria (South Africa)

    2009-08-15

    The effects of brown coal derived potassium humate on lymphocyte proliferation, cytokine production and complement activation were investigated in vitro. Potassium humate increased lymphocyte proliferation of phytohaemaglutinin A (PHA) and pokeweed mitogen (PWM) stimulated mononuclear lymphocytes (MNL) in vitro from concentrations of 20 to 80 {mu} g/ml, in a dose dependant manner. On the other hand potassium humate, at 40 {mu} g/ml, significantly inhibited the release of TNF-alpha, IL-1 beta, IL-6 and IL-10 by PHA stimulated MNL. Regarding complement activation it was found that potassium humate inhibits the activation of both the alternative and classical pathways without affecting the stability of the red blood cell membranes. These results indicate that the anti-inflammatory potential of potassium humate could be partially due to the inhibition of pro-inflammatory cytokines responsible for the initiation of these reactions as well as inhibition of complement activation. The increased lymphocyte proliferation observed, might be due to increased IL-2 production as previously been documented.

  10. The role of monocytes and T cells in 1,25-dihydroxyvitamin D3 mediated inhibition of B cell function in vitro

    DEFF Research Database (Denmark)

    Müller, K; Heilmann, C; Poulsen, L K

    1991-01-01

    1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) inhibits immunoglobulin production by human mononuclear cells (MNC) in vitro. The present study was undertaken to evaluate the role of T cells and monocytes in 1,25-(OH)2D3 induced suppression of B cell functions. The synthetic vitamin D3 analogue MC 903...... are not directly affected by 1,25-(OH)2D3 was further supported by the fact that 24 h of culture with 10(-8) M 1,25-(OH)2D3 failed to reduce immunoglobulin production by in vivo activated B cells....... was examined in parallel. 1,25-(OH)2D3 and MC 903 showed a dose-related inhibition of IgM, IgG and IgA plaque-forming cells in poke-weed mitogen (PWM) activated cultures of MNC. This effect was most likely mediated through impairment of T cell and monocyte functions. First, the inhibitory effect was seen after...

  11. Characterization and expression analysis of B Cell receptor accessory molecule CD79 gene in humphead snapper ( Lutjanus sanguineus)

    Science.gov (United States)

    Huang, Yucong; Yan, Xiuying; Cai, Shuanghu; Cai, Jia; Jian, Jichang; Lu, Yishan; Tang, Jufen; Wu, Zaohe

    2016-04-01

    CD79, a key component of the B cell antigen receptor complex, is composed of CD79α(Igα) and CD79β(Igβ) encoded by mb-1 and B29 respectively, and plays an important role in B cell signaling. In this study, we isolated and characterized mb-1 and B29 from humphead snapper ( Lutjanus sanguineus). Their tissue distribution and expression profiles after stimulations in vitro and in vivo were also investigated. The humphead snapper mb-1 and B29 contain open reading frames of 684 bp and 606 bp, encoding 227 amino acids and 201 amino acids, respectively. Both CD79α and CD79β possess signal peptide, extracellular Ig domain, transmembrane region and immunoreceptor tyrosine kinase activation motif (ITAM). Mb-1 is highly expressed in lymphoid organs (thymus, posterior kidney and spleen) and mucosal-associated lymphoid tissues (gill and intestine), while B29 is mainly detected in posterior kidney, spleen, gill and skin. Furthermore, transcription of mb-1 and B29 in head kidney leucocytes was up-regulated following lipopolysaccharide (LPS), pokeweed mitogen (PWM), and polyinosinic-polycytidylic acid (PolyI:C) stimulation, respectively, and their expression level in anterior kidney and spleen was also increased after challenged with formalin-inactived Vibrio harveyi. These results indicated that humphead snapper CD79 molecule might play an important role in immune response to pathogen infection.

  12. Comparison of the immunosuppressive effect of fractionated total lymphoid irradiation (TLI) vs conventional immunosuppression (CI) in renal cadaveric allotransplantation

    International Nuclear Information System (INIS)

    Waer, M.; Vanrenterghem, Y.; Ang, K.K.; van der Schueren, E.; Michielsen, P.; Vandeputte, M.

    1984-01-01

    Beginning in November 1981, eight patients with end stage diabetic nephropathy underwent renal cadaveric transplantation after TLI. Transplantation was done between 2 to 11 days after the end of a fractionated TLI to a total dose of 20 to 30 Gy. During the same observation period, 60 nondiabetic patients with end stage renal disease of different origin also received a cadaveric kidney graft, with a conventional regimen of immunosuppression that consists of anti-lymphocyte-globulin, tapering high doses of prednisone, and azathioprine. Phytohemagglutinin (PHA)-, concanavalin A (con A)-, and pokeweed mitogen (PWM)-induced blastogenesis, as well as the mixed lymphocyte reaction (MLR) and the cell-mediated lympholysis (CML) decreased progressively during the first months after conventional immunosuppression to 50% of the pretransplantation level, and remained there for the first year after transplantation. These tests were much more impaired after TLI and again no recovery occurred during the first year. In the clinic, the more profound immunosuppression in TLI patients was more frequently associated with viral infections (cytomegalovirus and herpes zoster). The incidence of rejections, however, was somewhat less frequent in the TLI-treated group and occurred significantly later. After TLI, the mean cumulative dose of steroids needed for kidney transplantation during the first year after transplantation could be substantially reduced

  13. ASH1L Suppresses Matrix Metalloproteinase through Mitogen-activated Protein Kinase Signaling Pathway in Pulpitis.

    Science.gov (United States)

    Bei, Yin; Tianqian, Hui; Fanyuan, Yu; Haiyun, Luo; Xueyang, Liao; Jing, Yang; Chenglin, Wang; Ling, Ye

    2017-02-01

    Pulpitis is an inflammation of dental pulp produced by a response to external stimuli. The response entails substantial cellular and molecular activities. Both genetic and epigenetic regulators contribute to the occurrence of pulpitis. However, the epigenetic mechanisms are still poorly understood. In this research, we studied the role of the absent, small, or homeotic-like (ASH1L) gene in the process of pulpitis. Human dental pulp cells (HDPCs) were stimulated with proinflammatory cytokine tumor necrosis factor alpha (TNF-α). Gene expression profiling was performed to assess the occurrence of epigenetic regulators. Pulp tissue from rat experimental pulpitis was subjected to immunofluorescence to detect the occurrence of ASH1L and trimethylation of lysine 4 histone 3 (H3K4me3). The presence of ASH1L in HDPCs that had been generated by TNF-α stimulation was analyzed by Western blot procedures and cellular immunofluorescence. Once detected, ASH1L was silenced through the use of specific small interfering RNA. The effects of ASH1L on the occurrence and operation of matrix metalloproteinases (MMPs) were then tested by analysis of quantitative polymerase chain reactions, Western blotting, and zymography. Chromatin immunoprecipitation was performed to detect whether ASH1L and H3K4me3 were present in the promoter regions of MMPs. We then used Western blot procedures to examine the nuclear factor kappa B and the mitogen-activated protein kinase (MAPK) responses to the silencing of ASH1L. We also examined the specific pathway involved in ASH1L regulation of the MMPs. After stimulating HDPCs with TNF-α, ASH1L emerged as 1 of the most strongly induced epigenetic mediators. We found that TNF-α treatment induced the expression of ASH1L through the nuclear factor kappa B and MAPK signal pathways. ASH1L was found in both the nucleus and the cytoplasm. TNF-α treatment was particularly active in inducing the accumulation of ASH1L in cellular cytoplasm. As is also consistent

  14. "THE STUDY OF DOSE-RESPONSE MITOGENIC EFFECT OF L-DOPA ON THE HUMAN PERIODONTAL LIGAMENT FIBROBLAST CELLS"

    Directory of Open Access Journals (Sweden)

    M. Zarabian

    2004-10-01

    Full Text Available Avulsion is one of the most serious emergencies in dental office. In the event of any problem, the tooth should be stored in a medium that supports the periodontal ligament cell viability. In other clinical situations, preserving media, growth factors and mitogenic products may be useful in repairing the traumatized tissues. It has been previously reported that levodopa (L-dopa accelerates healing by increasing the growth hormone level. In this study, the local effect of L-dopa, as a mitogen, on human periodontal ligament fibroblast (HPLF cells was evaluated. Samples from impacted or semiimpacted wisdom or canine teeth, which were devoid of inflammation, were taken. The cells obtained from this tissue were cultured in an appropriate medium. The passage numbers between 3-6 were taken for further experiments. The viability of HPLF cells, which were treated by L-dopa, was evaluated by trypan blue dye exclusion and neutral red assay. Results indicated that low concentration of L-dopa produces significant increase of these cells compared to control group. These results confirmed previous studies about direct action of L- dopa on the viability of HPLF cells. On the basis of this study and previous reports, presence of L-dopa in preserving media may be useful in increasing the self-life transferring HPLF cells.

  15. Collagen directly stimulates bladder smooth muscle cell growth in vitro: regulation by extracellular regulated mitogen activated protein kinase.

    Science.gov (United States)

    Herz, Daniel B; Aitken, Karen; Bagli, Darius J

    2003-11-01

    Bladders clinically subjected to excessive pressure or distention demonstrate an altered extracellular matrix (ECM) composition. We determined how an altered collagen substratum might affect bladder smooth muscle cell (bSMC) growth in vitro and probed the mechanism of this response. Primary culture rat bSMCs were seeded onto culture plates pre-coated with normal type I collagen (NC) or heat denatured type I collagen (DNC) under standard culture conditions. In separate experiments bSMCs from the 2 substrates were enzymatically released and changed to growth on normal collagen (NC-->NC or DNC-->NC) or denatured collagen (DNC-->DNC or NC-->DNC). At 24 hours proliferation was assessed by 3H-thymidine incorporation. Statistical significance in triplicate wells was determined by ANOVA. The proliferation of bSMCs on DNC was 5-fold greater than on NC (p DNC-->DNC) showed 2-fold further augmentation in proliferation (p DNC-->NC) (p NC) generated a 33% decrease in the already low proliferation rate (p DNC) (p DNC. However, mitogenicity is only partially reversible by re-introducing NC. These results demonstrate striking bSMC responsiveness to ECM conformation. Signaling through the extracellular regulated kinase mitogen activated protein kinase pathway supports bSMC-ECM interaction. We speculate that remodeling the ECM in vivo may regulate bSMC growth.

  16. Procalcitonin NH2-terminal cleavage peptide has no mitogenic effect on normal human osteoblast-like cells

    International Nuclear Information System (INIS)

    Hassager, C.; Bonde, S.K.; Anderson, M.A.; Rink, H.; Spelsberg, T.C.; Riggs, B.L.

    1991-01-01

    The NH2-terminal cleavage peptide of procalcitonin (N-proCT) recently was reported to be a bone cell mitogen. The authors have investigated the effect of N-proCT on the proliferation of normal human cells that have the phenotype of mature osteoblasts (hOB cells). N-proCT treatment for 24, 48, or 96 h in concentrations from 1 nM to 1 microM did not significantly increase [3H]thymidine uptake (means ranged from -19% to 38% of control, no significant differences) in hOB cells (6-10 cell strains per experiment) plated at four different densities. However, the hOB cells responded significantly to treatment with transforming growth factor β (3 ng/ml), bovine insulin (300 micrograms/ml), or 30% fetal calf serum, which were included in all experiments as positive controls. The [3H]thymidine uptake data were confirmed in a direct cell count experiment tested at 96 h. Thus they data do not support the hypothesis that N-proCT is a potent mitogen for normal human osteoblasts

  17. Induced Mitogenic Activity in AML-12 Mouse Hepatocytes Exposed to Low-dose Ultra-Wideband Electromagnetic Radiation

    Directory of Open Access Journals (Sweden)

    P. B. Tchounwou

    2005-04-01

    Full Text Available Ultra–wideband (UWB technology has increased with the use of various civilian and military applications. In the present study, we hypothesized that low-dose UWB electromagnetic radiation (UWBR could elicit a mitogenic effect in AML-12 mouse hepatocytes, in vitro. To test this hypothesis, we exposed AML-12 mouse hepatocytes, to UWBR in a specially constructed gigahertz transverse electromagnetic mode (GTEM cell. Cells were exposed to UWBR for 2 h at a temperature of 23°C, a pulse width of 10 ns, a repetition rate of 1 kHz, and field strength of 5-20 kV/m. UWB pulses were triggered by an external pulse generator for UWBR exposure but were not triggered for the sham exposure. We performed an MTT Assay to assess cell viability for UWBR-treated and sham-exposed hepatocytes. Data from viability studies indicated a time-related increase in hepatocytes at time intervals from 8-24 h post exposure. UWBR exerted a statistically significant (p < 0.05 dose-dependent response in cell viability in both serum-treated and serum free medium (SFM -treated hepatocytes. Western blot analysis of hepatocyte lysates demonstrated that cyclin A protein was induced in hepatocytes, suggesting that increased MTT activity after UWBR exposure was due to cell proliferation. This study indicates that UWBR has a mitogenic effect on AML-12 mouse hepatocytes and implicates a possible role for UWBR in hepatocarcinoma.

  18. The effects of selected drugs, including chlorpromazine and non-steroidal anti-inflammatory agents, on polyclonal IgG synthesis and interleukin 1 production by human peripheral blood mononuclear cells in vitro.

    Science.gov (United States)

    Martinez, F; Coleman, J W

    1989-01-01

    We tested a range of drugs for their effects on in vitro polyclonal IgG synthesis by human peripheral blood mononuclear cells (PBMC) stimulated with the lectin pokeweed mitogen (PWM). The test drugs were selected on the basis of reported disruptive effects on immune function in vivo. IgG production between day 4 and days 7 or 8 of culture was measured by biotin-streptavidin sandwich ELISA. The anti-psychotic agent chlorpromazine (0.55-1.7 microM) enhanced IgG synthesis to approximately double control levels. In contrast, the non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin, piroxicam, ibuprofen and aspirin inhibited IgG synthesis by up to 50%, with a rank order of potency that reflects their activity as inhibitors of cyclo-oxygenase. Phenytoin, procainamide, propylthiouracil, methimazole, D-penicillamine and D-penicillamine-L-cysteine all failed to modulate IgG synthesis at non-toxic concentrations. The potentiation and inhibition of IgG synthesis by chlorpromazine and indomethacin, respectively, was observed only when the drug was present during the first 24 h of culture. Neither chlorpromazine nor indomethacin, at non-toxic concentrations, affected PHA- and PWM-stimulated proliferation of PBMC. In addition, chlorpromazine, indomethacin and piroxicam, at concentrations which produced maximal modulation of IgG synthesis, and D-penicillamine and D-penicillamine-L-cysteine at 10 microM failed to influence production of interleukin-1-like activity. We conclude that chlorpromazine and NSAIDs, although they exert opposite effects on IgG synthesis, act at an early stage of B cell differentiation that appears to be independent of interleukin 1 synthesis and early proliferative events. PMID:2788047

  19. Evaluation of an in vitro blood-based assay to detect production of interferon-gamma by Mycobacterium bovis-infected white-tailed deer (Odocoileus virginianus).

    Science.gov (United States)

    Palmer, Mitchell V; Waters, W Ray; Whipple, Diana L; Slaughter, Ralph E; Jones, Stephen L

    2004-01-01

    Tuberculosis due to Mycobacterium bovis in captive Cervidae was identified as an important disease in the United States in 1990 and prompted the addition of captive Cervidae to the USDA Uniform Methods and Rules for eradication of bovine tuberculosis. As well, M. bovis infection was identified in free-ranging white-tailed deer in northeast Michigan in 1995. Tuberculosis in both captive and free-ranging Cervidae represents a serious challenge to the eradication of M. bovis infection from the United States. Currently, the only approved antemortem tests for tuberculosis in Cervidae are the intradermal tuberculin skin test and the blood tuberculosis test (BTB). At present, the BTB is not available in North America. Tuberculin skin testing of Cervidae is time-consuming and involves repeated animal handling and risk of injury to animals and humans. This study evaluated the potential of a new blood-based assay for tuberculosis in Cervidae that would decrease animal handling, stress, and losses due to injury. In addition, a blood-based assay could provide a more rapid diagnosis. Twenty 6-9-month-old white-tailed deer, male and female, were experimentally inoculated by instillation of 300 colony-forming units of M. bovis in the tonsillar crypts. Seven, age-matched uninfected deer served as controls. Blood was collected on days 90, 126, 158, 180, 210, 238, 263, and 307 after inoculation and was analyzed for the production of interferon-gamma (IFN-gamma) in response to incubation with M. bovis purified protein derivative (PPDb), M. avium PPDa, pokeweed mitogen (PWM), or media alone. Production of IFN-gamma in response to PPDb was significantly greater (P deer as compared with uninfected control deer, whereas IFN-gamma production to PWM did not differ significantly between infected and control deer. Measurement of IFN-gamma production to PPDb may serve as a useful assay for the antemortem diagnosis of tuberculosis in Cervidae.

  20. In vitro effect of chloroquine, mefloquine and quinine on human lymphocyte proliferative responses to malaria antigens and other antigens/mitogens

    DEFF Research Database (Denmark)

    Bygbjerg, I C; Theander, T G; Andersen, B J

    1986-01-01

    -thymidine incorporation. On a weight base, the most potent drug was mefloquine. At clinically relevant doses, chloroquine and mefloquine did not affect the response to malaria antigens, but mefloquine decreased the response to phytohaemagglutinin; quinine suppressed the response to all mitogens (with the exception......The effect of 3 antimalarial quinoline derivatives, chloroquine, mefloquine and quinine on human blood mononuclear cells in vitro was studied. High concentrations profoundly suppressed the proliferation of mitogen- and antigen-stimulated lymphocytes, as indicated by decreased 14C...

  1. OncoPPi-informed discovery of mitogen-activated protein kinase kinase 3 as a novel binding partner of c-Myc | Office of Cancer Genomics

    Science.gov (United States)

    Mitogen-activated protein kinase kinase 3 (MKK3) is a dual threonine/tyrosine protein kinase that regulates inflammation, proliferation and apoptosis through specific phosphorylation and activation of the p38 mitogen-activated protein kinase. However, the role of MKK3 beyond p38-signaling remains elusive. Recently, we reported a protein-protein interaction (PPI) network of cancer-associated genes, termed OncoPPi, as a resource for the scientific community to generate new biological models. Analysis of the OncoPPi connectivity identified MKK3 as one of the major hub proteins in the network.

  2. p38gamma and p38delta mitogen activated protein kinases (MAPKs, new stars in the MAPK galaxy

    Directory of Open Access Journals (Sweden)

    Alejandra eEscós

    2016-04-01

    Full Text Available The protein kinases p38γ and p38δ belong to the p38 mitogen-activated protein kinase (MAPK family. p38MAPK signalling controls many cellular processes and is one of the most conserved mechanisms in eukaryotes for the cellular response to environmental stress and inflammation. Although p38γ and p38δ are widely expressed, it is likely that they perform specific functions in different tissues. Their involvement in human pathologies such as inflammation-related diseases or cancer is starting to be uncovered. In this article we give a general overview and highlight recent advances made in defining the functions of p38γ and p38δ, focusing in innate immunity and inflammation. We consider the potential of the pharmacological targeting of MAPK pathways to treat autoimmune and inflammatory diseases and cancer

  3. Modulation of mitogen-activated protein kinase-activated protein kinase 3 by hepatitis C virus core protein

    DEFF Research Database (Denmark)

    Ngo, HT; Pham, Long; Kim, JW

    2013-01-01

    and protein levels of MAPKAPK3 were elevated in both HCV subgenomic replicon cells and cell culture-derived HCV (HCVcc)-infected cells. Silencing of MAPKAPK3 expression resulted in decreases in both protein and HCV infectivity levels but not in the intracellular HCV RNA level. We showed that MAPKAPK3......Hepatitis C virus (HCV) is highly dependent on cellular proteins for its own propagation. In order to identify the cellular factors involved in HCV propagation, we performed protein microarray assays using the HCV core protein as a probe. Of ~9,000 host proteins immobilized in a microarray......, approximately 100 cellular proteins were identified as HCV core-interacting partners. Of these candidates, mitogen-activated protein kinase-activated protein kinase 3 (MAPKAPK3) was selected for further characterization. MAPKAPK3 is a serine/threonine protein kinase that is activated by stress and growth...

  4. Expression and sequence analysis of the Blumeria graminis mitogen-activated protein kinase genes, mpk1 and mpk2.

    Science.gov (United States)

    Zhang, Z; Gurr, S J

    2001-03-21

    Mitogen-activated protein (MAP) kinases represent a group of serine/threonine kinases which play a pivotal role in signal transduction processes in eukaryotic cells. Using degenerate PCR primer design based on published and aligned MAP kinase sequences we have cloned and characterised two MAP kinase genes from the barley powdery mildew fungus, Blumeria graminis. We have utilised 'step down' PCR to attain the full length mildew genomic clones. The single-copy genes, named mpk1 and mpk2, encode putative proteins of 356 and 410 amino acids and carry three and four introns, respectively. Expression studies, using RT-PCR, reveal a differing pattern of tissue gene expression with mpk1 and mpk2 during germling morphogenesis and this is compared with the constitutive expression of the 'control' beta-tubulin gene.

  5. Involvement of the mitogen-activated protein (MAP kinase signalling pathway in host cell invasion by Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Robert-Gangneux F.

    2000-06-01

    Full Text Available Little is known about signalling in Toxoplasma gondii, but it is likely that protein kinases might play a key role in the parasite proliferation, differentiation and probably invasion. We previously characterized Mitogen-Activated Protein (MAP kinases in T. gondii lysates. In this study, cultured cells were tested for their susceptibility to Toxoplasma gondii infection after tachyzoite pretreatment with drugs interfering with AMP kinase activation pathways. Protein kinases inhibitors, i.e. genistein, R031-8220 and PD098059, reduced tachyzoite infectivity by 38 ± 4.5 %, 85.5 ± 9 % and 56 ± 10 %, respectively. Conversely, protein kinases activators, i.e. bombesin and PMA, markedly increased infectivity (by 202 ± 37 % and 258 ± 14 %, respectively. These results suggest that signalling pathways involving PKC and AAAP kinases play a role in host cell invasion by Toxoplasma.

  6. Fibroblast growth factors 7 and 10 are involved in ameloblastoma proliferation via the mitogen-activated protein kinase pathway.

    Science.gov (United States)

    Nakao, Yu; Mitsuyasu, Takeshi; Kawano, Shintaro; Nakamura, Norifumi; Kanda, Shiori; Nakamura, Seiji

    2013-11-01

    Ameloblastoma is an epithelial benign tumor of the odontogenic apparatus and its growth mechanisms are not well understood. Fibroblast growth factor (FGF) 3, FGF7 and FGF10, which are expressed by the neural crest-derived ectomesenchymal cells, induce the proliferation of odontogenic epithelial cells during tooth development. Therefore, we examined the expression and function of these FGFs in ameloblastoma. We examined 32 cases of ameloblastoma as well as AM-1 cells (an ameloblastoma cell line) and studied the expression of FGF3, FGF7, FGF10 and their specific receptors, namely, FGF receptor (FGFR) 1 and FGFR2. Proliferation, mitogen-activated protein kinase (MAPK) signaling and PI3K signaling were examined in AM-1 cells after the addition of FGF7, FGF10 and these neutralizing antibodies. The expression of FGF7, FGF10, FGFR1 and FGFR2 was detected in ameloblastoma cells and AM-1 cells, while that of FGF3 was not. FGF7 and FGF10 stimulated AM-1 cell proliferation and phosphorylation of p44/42 MAPK. However, Akt was not phosphorylated. Blocking the p44/42 MAPK pathway by using a specific mitogen-activated protein/extracellular signal-regulated kinase (MEK) inhibitor (U0126) completely neutralized the effects of FGF7 and FGF10 on AM-1 cell proliferation. However, Anti FGF7 and FGF10 neutralizing antibodies did not decrease cell proliferation and MAPK phosphorylation of AM-1 cells. These results suggested that FGF7 and FGF10 are involved in the proliferation of ameloblastoma cells through the MAPK pathway.

  7. Mitogenic signaling pathways in the liver of growth hormone (GH)-overexpressing mice during the growth period.

    Science.gov (United States)

    Martinez, Carolina S; Piazza, Verónica G; González, Lorena; Fang, Yimin; Bartke, Andrzej; Turynl, Danie; Miquet, Johanna G; Sotelo, Ana I

    2016-01-01

    Growth hormone (GH) is a pleiotropic hormone that triggers STATs, ERK1/2 and Akt signaling, related to cell growth and proliferation. Transgenic mice overexpressing GH present increased body size, with a disproportionate liver enlargement due to hypertrophy and hyperplasia of the hepatocytes. We had described enhanced mitogenic signaling in liver of young adult transgenic mice. We now evaluate the activation of these signaling cascades during the growth period and relate them to the morphological alterations found. Signaling mediators, cell cycle regulators and transcription factors involved in cellular growth in the liver of GH-overexpressing growing mice were assessed by immunoblotting, RT-qPCR and immunohistochemistry. Hepatocyte enlargement can be seen as early as 2-weeks of age in GH-overexpressing animals, although it is more pronounced in young adults. Levels of cell cycle mediators PCNA and cyclin D1, and transcription factor c-Jun increase with age in transgenic mice with no changes in normal mice, whereas c-Myc levels are higher in 2-week-old transgenic animals and cyclin E levels decline with age for both genotypes. STAT3, Akt and GSK3 present higher activation in the adult transgenic mice than in the growing animals, while for c-Src and mTOR, phosphorylation in GH-overexpressing mice is higher than in control siblings at 4 and 9 weeks of age. No significant changes are observed for ERK1/2, neither by age or genotype. Thus, the majority of the mitogenic signaling pathways are gradually up-regulated in the liver of GH-transgenic mice, giving rise to the hepatic morphological changes these mice exhibit.

  8. A Role for Mitogen- and Stress-Activated Kinase 1 in L-DOPA-Induced Dyskinesia and ∆FosB Expression

    DEFF Research Database (Denmark)

    Feyder, Michael; Södersten, Erik; Santini, Emanuela

    2014-01-01

    of mitogen- and stress-activated kinase 1 (MSK1), a downstream target of extracellular signal-regulated kinases 1 and 2, and an important regulator of transcription in LID. METHODS: 6-Hydroxydopamine was used to produce a model of Parkinson's disease in MSK1 knockout mice and in ∆FosB- or ∆c...

  9. The immunodeficiency of bone marrow-transplanted patients. The effect of patient lymphocytes on the response of donor lymphocytes to mitogens and allogeneic cells

    DEFF Research Database (Denmark)

    Ødum, Niels; Hofmann, B; Platz, P

    1985-01-01

    Lymphocytes from patients after bone marrow transplantation (BMT) are in most cases predominantly of the Leu-2+ (cytotoxic/suppressor) phenotypes and are almost unresponsive to mitogens. In contrast, normal Leu-3+-depleted, Leu-2+-enriched lymphocyte suspensions retain approximately 50...

  10. Activation of overexpressed receptors for insulin and epidermal growth factor interferes in mitogenic signaling without affecting the activation of p21ras

    NARCIS (Netherlands)

    Osterop, A.P.R.M.; Medema, R.H.; Ouwens, D.M.; Zon, G.C.M. van der; Möller, W.; Maassen, J.A.

    1994-01-01

    Activated receptors with a tyrosine kinase activity induce a variety of responses like changes in the differentiation and mitogenic status of cells. These responses are mediated in part by p21ras. Some of these activated receptors induce in certain cell types a pronounced, but transient, increase in

  11. Constitutive Activation of the Fission Yeast Pheromone-Responsive Pathway Induces Ectopic Meiosis and Reveals Ste11 as a Mitogen-Activated Protein Kinase Target

    DEFF Research Database (Denmark)

    Kjærulff, Søren; Lautrup-Larsen, I.; Truelsen, S.

    2005-01-01

    In the fission yeast Schizosaccharomyces pombe, meiosis normally takes place in diploid zygotes resulting from conjugation of haploid cells. In the present study, we report that the expression of a constitutively activated version of the pheromone-responsive mitogen-activated protein kinase kinase...

  12. Isolation of a glucosamine binding leguminous lectin with mitogenic activity towards splenocytes and anti-proliferative activity towards tumor cells.

    Science.gov (United States)

    Chan, Yau Sang; Wong, Jack Ho; Fang, Evandro Fei; Pan, Wenliang; Ng, Tzi Bun

    2012-01-01

    A dimeric 64-kDa glucosamine-specific lectin was purified from seeds of Phaseolus vulgaris cv. "brown kidney bean." The simple 2-step purification protocol involved affinity chromatography on Affi-gel blue gel and gel filtration by FPLC on Superdex 75. The lectin was absorbed on Affi-gel blue gel and desorbed using 1M NaCl in the starting buffer. Gel filtration on Superdex 75 yielded a major absorbance peak that gave a single 32-kDa band in SDS-PAGE. Hemagglutinating activity was completely preserved when the ambient temperature was in the range of 20 °C-60 °C. However, drastic reduction of the activity occurred at temperatures above 65 °C. Full hemagglutinating activity of the lectin was observed at an ambient pH of 3 to 12. About 50% activity remained at pH 0-2, and only residual activity was observed at pH 13-14. Hemagglutinating activity of the lectin was inhibited by glucosamine. The brown kidney bean lectin elicited maximum mitogenic activity toward murine splenocytes at 2.5 µM. The mitogenic activity was nearly completely eliminated in the presence of 250 mM glucosamine. The lectin also increased mRNA expression of the cytokines IL-2, TNF-α and IFN-γ. The lectin exhibited antiproliferative activity toward human breast cancer (MCF7) cells, hepatoma (HepG2) cells and nasopharyngeal carcinoma (CNE1 and CNE2) cells with IC(50) of 5.12 µM, 32.85 µM, 3.12 µM and 40.12 µM respectively after treatment for 24 hours. Flow cytometry with Annexin V and propidum iodide staining indicated apoptosis of MCF7 cells. Hoechst 33342 staining also indicated formation of apoptotic bodies in MCF7 cells after exposure to brown kidney bean lectin. Western blotting revealed that the lectin-induced apoptosis involved ER stress and unfolded protein response.

  13. Light-mediated Reversible Modulation of the Mitogen-activated Protein Kinase Pathway during Cell Differentiation and Xenopus Embryonic Development.

    Science.gov (United States)

    Krishnamurthy, Vishnu V; Turgeon, Aurora J; Khamo, John S; Mondal, Payel; Sharum, Savanna R; Mei, Wenyan; Yang, Jing; Zhang, Kai

    2017-06-15

    Kinase activity is crucial for a plethora of cellular functions, including cell proliferation, differentiation, migration, and apoptosis. During early embryonic development, kinase activity is highly dynamic and widespread across the embryo. Pharmacological and genetic approaches are commonly used to probe kinase activities. Unfortunately, it is challenging to achieve superior spatial and temporal resolution using these strategies. Furthermore, it is not feasible to control the kinase activity in a reversible fashion in live cells and multicellular organisms. Such a limitation remains a bottleneck for achieving a quantitative understanding of kinase activity during development and differentiation. This work presents an optogenetic strategy that takes advantage of a bicistronic system containing photoactivatable proteins Arabidopsis thaliana cryptochrome 2 (CRY2) and the N-terminal domain of cryptochrome-interacting basic-helix-loop-helix (CIBN). Reversible activation of the mitogen-activated protein kinase (MAPK) signaling pathway is achieved through light-mediated protein translocation in live cells. This approach can be applied to mammalian cell cultures and live vertebrate embryos. This bicistronic system can be generalized to control the activity of other kinases with similar activation mechanisms and can be applied to other model systems.

  14. Mitogen-activated protein kinase Hog1 is activated in response to curcumin exposure in the budding yeast Saccharomyces cerevisiae.

    Science.gov (United States)

    Azad, Gajendra Kumar; Singh, Vikash; Thakare, Mayur Jankiram; Baranwal, Shivani; Tomar, Raghuvir Singh

    2014-12-19

    Curcumin (CUR), an active polyphenol derived from the spice turmeric, has been traditionally used for centuries in ancient Indian medicine to treat a number of diseases. The physiological effects of CUR have been shown to be diverse; however, the target molecules and pathways that CUR affects have yet to be fully described. Here, we demonstrate for the first time that the budding yeast mitogen-activated protein kinase (MAPK) Hog1 is essential for the response to CUR. Moreover, CUR-induced Hog1 phosphorylation was rescued by supplementation of iron to the growth medium. Hog1 was rapidly phosphorylated upon CUR treatment, but unlike the response to hyperosmotic shock (0.8 M NaCl), it remains activated for an extended period of time. A detailed analysis of HOG pathway mutants revealed that Pbs2p, Ptc2p, and Ssk2p are required for optimal CUR-induced Hog1 phosphorylation. We also observed a Hog1 dependent transcriptional response to CUR treatment that involved the up-regulation of glycerol-3-phosphate dehydrogenase 1 (GPD1), a factor that is essential for the hyperosmotic stress response. Our present finding revealed the role of Hog1 MAPK in regulation of CUR-induced transcriptional response. We anticipate that our finding will enhance the understanding on the molecular mode of action of CUR on S. cerevisiae.

  15. Up-regulation of integrin α6β4 expression by mitogens involved in dairy cow mammary development.

    Science.gov (United States)

    Zhao, Feng; Liu, Chang; Hao, Yu-Meng; Qu, Bo; Cui, Ying-Jun; Zhang, Na; Gao, Xue-Jun; Li, Qing-Zhang

    2015-03-01

    In dairy cows, the extracellular microenvironment varies significantly from the virgin state to lactation. The function of integrin α6β4 is dependent on cell type and extracellular microenvironment, and the precise expression profile of α6β4 and its effects on mammary development remain to be determined. In the present study, real-time PCR and immunohistochemistry were used to analyze the expression and localization of integrin α6β4 in Holstein dairy cow mammary glands. The effects of integrin α6β4 on the proliferation induced by mammogenic mitogens were identified by blocking integrin function in purified dairy cow mammary epithelial cells (DCMECs). The results showed that the localization of β4 subunit and its exclusive partner the α6 subunit were not consistent but were co-localized in basal luminal cells and myoepithelial cells, appearing to prefer the basal surface of the plasma membrane. Moreover, α6 and β4 subunit messenger RNA (mRNA) levels changed throughout the stages of dairy cow mammary development, reflected well by protein levels, and remained higher in the virgin and pregnancy states, with duct/alveolus morphogenesis and active cell proliferation, than during lactation, when growth arrest is essential for mammary epithelial cell differentiation. Finally, the upregulation of integrin expression by both mammogenic growth hormone and insulin-like growth factor-1 and the inhibited growth of DCMECs by function-blocking integrin antibodies confirmed that integrin α6β4 was indeed involved in dairy cow mammary development.

  16. Mitogen-Activated Protein Kinases Are Activated in Placental Injury in Rat Model of Acute Pancreatitis in Pregnancy.

    Science.gov (United States)

    Zuo, Teng; Yu, Jia; Wang, Wei-Xing; Zhao, Kai-Liang; Chen, Chen; Deng, Wen-Hong; He, Xiao-Bo; Wang, Peng; Shi, Qiao; Guo, Wen-Yi

    2016-07-01

    To establish a rat model of acute pancreatitis in pregnancy (APIP) and evaluate its general presentations, assess placental injury, and discuss possible mechanisms. The APIP rat model was induced by sodium taurocholate in Sprague-Dawley rats of later gestation. Normal and sham-operated (SO) rats in later gestation were set as controls, 3 time points were set in SO and APIP groups to determine optimal modeling time. Histological changes of pancreas and placenta were assessed. Placental injury was determined by immunohistochemistry stain of caspase-3. Serum levels of amylase, lipase, and Ca; proinflammatory cytokines as tumor necrosis factor-α, interleukin-1β (IL-1β), IL-6, and anti-inflammatory cytokine IL-10 by enzyme-linked immunosorbent assay; mitogen-activated protein kinases and their phosphorylated forms by Western blotting. Pancreatic necrotizing and placental injury occurred in time-dependent patterns. Serum levels of amylase and lipase significantly increased but Ca decreased; tumor necrosis factor-α, IL-1β, IL-6, and IL-10 were all increased in the APIP group; c-Jun N-terminal kinase, p38, and ERK1/2 were activated but with different distributing patterns in the placenta. Placental injury is involved in the rat model of APIP, and a modeling time of 6 hours is optimal and conducive to further studies; c-Jun N-terminal kinase and p38 may play important roles in placental injury during APIP.

  17. Riboflavin-Induced Disease Resistance Requires the Mitogen-Activated Protein Kinases 3 and 6 in Arabidopsis thaliana.

    Science.gov (United States)

    Nie, Shengjun; Xu, Huilian

    2016-01-01

    As a resistance elicitor, riboflavin (vitamin B2) protects plants against a wide range of pathogens. At molecular biological levels, it is important to elucidate the signaling pathways underlying the disease resistance induced by riboflavin. Here, riboflavin was tested to induce resistance against virulent Pseudomonas syringae pv. Tomato DC3000 (Pst DC3000) in Arabidopsis. Results showed that riboflavin induced disease resistance based on MAPK-dependent priming for the expression of PR1 gene. Riboflavin induced transient expression of PR1 gene. However, following Pst DC3000 inoculation, riboflavin potentiated stronger PR1 gene transcription. Further was suggested that the transcript levels of mitogen-activated protein kinases, MPK3 and MPK6, were primed under riboflavin. Upon infection by Pst DC3000, these two enzymes were more strongly activated. The elevated activation of both MPK3 and MPK6 was responsible for enhanced defense gene expression and resistance after riboflavin treatment. Moreover, riboflavin significantly reduced the transcript levels of MPK3 and MPK6 by application of AsA and BAPTA, an H2O2 scavenger and a calcium (Ca2+) scavenger, respectively. In conclusion, MPK3 and MPK6 were responsible for riboflavin-induced resistance, and played an important role in H2O2- and Ca2+-related signaling pathways, and this study could provide a new insight into the mechanistic study of riboflavin-induced defense responses.

  18. p38 mitogen activated protein kinase controls two successive-steps during the early mesodermal commitment of embryonic stem cells.

    Science.gov (United States)

    Barruet, Emilie; Hadadeh, Ola; Peiretti, Franck; Renault, Valérie M; Hadjal, Yasmine; Bernot, Denis; Tournaire, Roselyne; Negre, Didier; Juhan-Vague, Irène; Alessi, Marie-Christine; Binétruy, Bernard

    2011-07-01

    Embryonic stem (ES) cells differentiate in vitro into all cell lineages. We previously found that the p38 mitogen activated kinase (p38MAPK) pathway controls the commitment of ES cells toward either cardiomyogenesis (p38 on) or neurogenesis (p38 off ). In this study, we show that p38α knock-out ES cells do not differentiate into cardiac, endothelial, smooth muscle, and skeletal muscle lineages. Reexpression of p38MAPK in these cells partially rescues their mesodermal differentiation defects and corrects the high level of spontaneous neurogenesis of knock-out cells. Wild-type ES cells were treated with a p38MAPK-specific inhibitor during the differentiation process. These experiments allowed us to identify 2 early independent successive p38MAPK functions in the formation of mesodermal lineages. Further, the first one correlates with the regulation of the expression of Brachyury, an essential mesodermal-specific transcription factor, by p38MAPK. In conclusion, by genetic and biochemical approaches, we demonstrate that p38MAPK activity is essential for the commitment of ES cell into cardiac, endothelial, smooth muscle, and skeletal muscle mesodermal lineages.

  19. Mitogenic activation of B cells in vitro: the properties of adherent accessory cells as revealed by partition analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kettman, J.R.; Soederberg, A.; Lefkovits, I.

    1986-08-15

    The requirement of B cells activated by mitogen (dextran sulfate plus lipopolysaccharide) for accessory cells was studied by partition analysis. Small numbers of splenic B cells were activated to clonal growth, as determined by visual inspection, and to immunoglobulin (Ig) synthesis, as determined by release of Ig into the culture fluid. By placing irradiated adherent cells in the periphery of the microculture wells and forcing responding cells to different areas of the well (slant experiments), it was observed that no cell contact was necessary for B cell activation, and that promoted contact (Rock and Roll experiments) does not increase the efficiency of activation. Sequential microcultures suggest that only some irradiated adherent cells act as accessory cells, but they can perform this function to more than one B cell. Attempts to perform limiting dilution analysis by varying irradiated adherent cell input showed non-single-hit behavior. When the data were rearranged, taking into account the distribution of irradiated adherent cells, then single-hit behavior with about 1 to 5% of irradiated adherent cells acting as an accessory cells for B cell clonal activation was observed. The evidence suggests that an uncommon irradiated adherent cell releases a soluble factor necessary for B cell activation and/or clonal proliferation.

  20. Presenilin-2 regulates the degradation of RBP-Jk protein through p38 mitogen-activated protein kinase.

    Science.gov (United States)

    Kim, Su-Man; Kim, Mi-Yeon; Ann, Eun-Jung; Mo, Jung-Soon; Yoon, Ji-Hye; Park, Hee-Sae

    2012-03-01

    Transcriptional regulation performs a central role in Notch1 signaling by recombining binding protein Suppressor of Hairless (RBP-Jk)--a signaling pathway that is widely involved in determination of cell fate. Our earlier work demonstrated the possible regulation of the Notch1-RBP-Jk pathway through protein degradation of RBP-Jk; however, the potential regulator for the degradation of RBP-Jk remains to be determined. Here, we report that the expression of endogenous and exogenous RBP-Jk was increased significantly in cells treated with proteasome- and lysosome-specific inhibitors. The effects of these inhibitors on RBP-Jk occurred in a dose- and time-dependent manner. The level of RBP-Jk protein was higher in presenilin-2 (PS2)-knockout cells than in presenilin-1 (PS1)-knockout cells. Furthermore, the level of RBP-Jk was decreased by expression of PS2 in PS1 and PS2 double-knockout cells. We also found that PS1-knockout cells treated with a specific inhibitor of p38 mitogen-activated protein kinase ∂ (MAPK) had significantly increased levels of RBP-Jk. p38 MAPK phosphorylates RBP-Jk at Thr339 by physical binding, which subsequently induces the degradation and ubiquitylation of the RBP-Jk protein. Collectively, our results indicate that PS2 modulates the degradation of RBP-Jk through phosphorylation by p38 MAPK.

  1. TRAF6 promotes myogenic differentiation via the TAK1/p38 mitogen-activated protein kinase and Akt pathways.

    Directory of Open Access Journals (Sweden)

    Fang Xiao

    Full Text Available p38 mitogen-activated protein kinase (MAPK is an essential kinase involved in myogenic differentiation. Although many substrates of p38 MAPK have been identified, little is known about its upstream activators during myogenic differentiation. TRAF6 is known to function in cytokine signaling during inflammatory responses. However, not much is known about its role in myogenic differentiation and muscle regeneration. We showed here that TRAF6 and its intrinsic ubiquitin E3 ligase activity are required for myogenic differentiation. In mouse myoblasts, knockdown of TRAF6 compromised the p38 MAPK and Akt pathways, while deliberate activation of either pathway rescued the differentiation defect caused by TRAF6 knockdown. TAK1 acted as a key signal transducer downstream of TRAF6 in myogenic differentiation. In vivo, knockdown of TRAF6 in mouse muscles compromised the injury-induced muscle regeneration without impairing macrophage infiltration and myoblast proliferation. Collectively, we demonstrated that TRAF6 promotes myogenic differentiation and muscle regeneration via the TAK1/p38 MAPK and Akt pathways.

  2. Analysis of Mitogen-Activated Protein Kinases in Bone and Cartilage of Patients with Rheumatoid Arthritis Treated with Abatacept

    Directory of Open Access Journals (Sweden)

    Katsuaki Kanbe

    2016-01-01

    Full Text Available The aim of this study was to analyze the histological changes related to mitogen-activated protein (MAP kinases in bone and cartilage treated with abatacept for rheumatoid arthritis (RA. A total of 20 patients of bone and cartilage were assessed: 10 abatacept with methotrexate (MTX-treated RA patients were compared with 10 MTX-treated RA patients (control. The histology of bone and cartilage was observed by staining with hematoxylin and eosin and analyzed immunohistochemically for the expression of tumor necrosis factor-α, interleukin-6, CD4 (T cell, CD68 (macrophage, receptor activator of nuclear kappa-B ligand, osteoprotegerin, osteopontin, CD29 (β-1 integrin, phospho-p38 MAPK (Tyr180/Tyr182, phospho-p44/42 MAPK (extracellular signal-regulated kinase, ERK1/ERK2, and phosphor-c-Jun N-terminal kinase. The expressions of CD29 known as mechanoreceptor and ERK known as mechanotransduction signal protein in MAP kinases in the bone and cartilage of patients treated with abatacept were significantly different from those of control. These findings suggest that increases in CD29 and ERK in MAP kinases may change the metabolism of bone and cartilage in RA patients treated with abatacept.

  3. Heat Shock Proteins and Mitogen-activated Protein Kinases in Steatotic Livers Undergoing Ischemia-Reperfusion: Some Answers

    Science.gov (United States)

    Massip-Salcedo, Marta; Casillas-Ramirez, Araní; Franco-Gou, Rosah; Bartrons, Ramón; Ben Mosbah, Ismail; Serafin, Anna; Roselló-Catafau, Joan; Peralta, Carmen

    2006-01-01

    Ischemic preconditioning protects steatotic livers against ischemia-reperfusion (I/R) injury, but just how this is achieved is poorly understood. Here, I/R or preconditioning plus I/R was induced in steatotic and nonsteatotic livers followed by investigating the effect of pharmacological treatments that modulate heat shock proteins (HSPs) and mitogen-activated protein kinases (MAPKs). MAPKs, HSPs, protein kinase C, and transaminase levels were measured after reperfusion. We report that preconditioning increased HSP72 and heme-oxygenase-1 (HO-1) at 6 and 24 hours of reperfusion, respectively. Unlike nonsteatotic livers, steatotic livers benefited from HSP72 activators (geranylgeranylacetone) throughout reperfusion. This protection seemed attributable to HO-1 induction. In steatotic livers, preconditioning and geranylgeranylacetone treatment (which are responsible for HO-1 induction) increased protein kinase C activity. HO-1 activators (cobalt(III) protoporphyrin IX) protected both liver types. Preconditioning reduced p38 MAPK and c-Jun N-terminal kinase (JNK), resulting in HSP72 induction though HO-1 remained unmodified. Like HSP72, both p38 and JNK appeared not to be crucial in preconditioning, and inhibitors of p38 (SB203580) and JNK (SP600125) were less effective against hepatic injury than HO-1 activators. These results provide new data regarding the mechanisms of preconditioning and may pave the way to the development of new pharmacological strategies in liver surgery. PMID:16651615

  4. p38 Mitogen Activated Protein Kinase (MAPK): A New Therapeutic Target for Reducing the Risk of Adverse Pregnancy Outcomes

    Science.gov (United States)

    Menon, Ramkumar; Papaconstantinou, John

    2016-01-01

    Introduction Spontaneous preterm birth (PTB) and preterm premature rupture of the membranes (pPROM) remain as a major clinical and therapeutic problem for intervention and management. Current strategies, based on our knowledge of pathways of preterm labor, have only been effective, in part, due to major gaps in our existing knowledge of risks and risk specific pathways. Areas covered Recent literature has identified physiologic aging of fetal tissues as a potential mechanistic feature of normal parturition. This process is affected by telomere dependent and p38 mitogen activated protein kinase (MAPK) induced senescence activation. Pregnancy associated risk factors can cause pathologic activation of this pathway that can cause oxidative stress induced p38 MAPK activation leading to senescence and premature aging of fetal tissues. Premature aging is associated with sterile inflammation capable of triggering preterm labor or preterm premature rupture of membranes. Preterm activation of p38MAPK can be considered as a key contributor to adverse pregnancies. Expert Opinion This review considers p38MAPK activation as a potential target for therapeutic interventions to prevent adverse pregnancy outcomes mediated by stress factors. In this review, we propose multiple strategies to prevent p38MAPK activation and its functional effects. PMID:27459026

  5. Outer Membrane Protein 25 of Brucella Activates Mitogen-Activated Protein Kinase Signal Pathway in Human Trophoblast Cells

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2017-12-01

    Full Text Available Outer membrane protein 25 (OMP25, a virulence factor from Brucella, plays an important role in maintaining the structural stability of Brucella. Mitogen-activated protein kinase (MAPK signal pathway widely exists in eukaryotic cells. In this study, human trophoblast cell line HPT-8 and BALB/c mice were infected with Brucella abortus 2308 strain (S2308 and 2308ΔOmp25 mutant strain. The expression of cytokines and activation of MAPK signal pathway were detected. We found that the expressions of tumor necrosis factor-α, interleukin-1, and interleukin-10 (IL-10 were increased in HPT-8 cells infected with S2308 and 2308ΔOmp25 mutant. S2308 also activated p38 phosphorylation protein, extracellular-regulated protein kinases (ERK, and Jun-N-terminal kinase (JNK from MAPK signal pathway. 2308ΔOmp25 could not activate p38, ERK, and JNK branches. Immunohistochemistry experiments showed that S2308 was able to activate phosphorylation of p38 and ERK in BABL/c mice. However, 2308ΔOmp25 could weakly activate phosphorylation of p38 and ERK. These results suggest that Omp25 played an important role in the process of Brucella activation of the MAPK signal pathway.

  6. Molecular Cloning and Characterization of a P38-Like Mitogen-Activated Protein Kinase fromEchinococcus granulosus.

    Science.gov (United States)

    Lü, Guodong; Li, Jing; Zhang, Chuanshan; Li, Liang; Bi, Xiaojuan; Li, Chaowang; Fan, Jinliang; Lu, Xiaomei; Vuitton, Dominique A; Wen, Hao; Lin, Renyong

    2016-12-01

    Cystic echinococcosis (CE) treatment urgently requires a novel drug. The p38 mitogen-activated protein kinases (MAPKs) are a family of Ser/Thr protein kinases, but still have to be characterized in Echinococcus granulosus . We identified a 1,107 bp cDNA encoding a 368 amino acid MAPK protein (Egp38) in E. granulosus . Egp38 exhibits 2 distinguishing features of p38-like kinases: a highly conserved T-X-Y motif and an activation loop segment. Structural homology modeling indicated a conserved structure among Egp38, EmMPK2, and H. sapiens p38α, implying a common binding mechanism for the ligand domain and downstream signal transduction processing similar to that described for p38α. Egp38 and its phosphorylated form are expressed in the E. granulosus larval stages vesicle and protoscolices during intermediate host infection of an intermediate host. Treatment of in vitro cultivated protoscolices with the p38-MAPK inhibitor ML3403 effectively suppressed Egp38 activity and led to significant protoscolices death within 5 days. Treatment of in vitro-cultivated protoscolices with TGF-β1 effectively induced Egp38 phosphorylation. In summary, the MAPK, Egp38, was identified in E. granulosus , as an anti-CE drug target and participates in the interplay between the host and E. granulosus via human TGF-β1.

  7. Chitosan Controls Postharvest Decay on Cherry Tomato Fruit Possibly via the Mitogen-Activated Protein Kinase Signaling Pathway.

    Science.gov (United States)

    Zhang, Danfeng; Wang, Hongtao; Hu, Yi; Liu, Yongsheng

    2015-08-26

    The inhibitive effects of chitosan on gray mold caused by Botrytis cinerea on cherry tomato fruit were evaluated. Decay incidence was tested on tomato stored at 22 °C. Hydrogen peroxide accumulation, malondialdehyde (MDA) production, peroxidase (POD) activity, and several related gene expressions (including MPK3, MPK6, PR1a1, and PR5) were determined. Results showed that 0.2% of chitosan solution significantly inhibited the tomato gray mold 3 days after inoculation. Hydrogen peroxide accumulated in the fruit epidermal peel along with chitosan treatment, while MDA production was not increased. POD activity was remarkably enhanced by the application of chitosan. The relative expressions of MPK3, MPK6, and PR1a1 were significantly induced in 10 min after chitosan treatment, while PR5 was induced in 20 min. These findings suggested that the effects of chitosan on inhibiting gray mold in cherry tomato fruit were probably associated with the mitogen-activated protein kinase (MAPK) signaling pathway.

  8. Involvement of the mitogen-activated protein kinase kinase 2 in the induction of cell dissociation in pancreatic cancer.

    Science.gov (United States)

    Tan, Xiaodong; Egami, Hiroshi; Kamohara, Hidenobu; Ishikawa, Shinji; Kurizaki, Takashi; Yoshida, Naoya; Tamori, Yasuhiko; Takai, Eiji; Hirota, Masahiko; Ogawa, Michio

    2004-01-01

    In our previous investigation, mitogen-activated protein kinase kinase 2 (MEK2) was detected as a factor which was correlated to the potential of invasion-metastasis. In this study, the immunocytochemical, immunohistochemical and mRNA expressions of MEK2 were examined in pancreatic cancer cell lines and tissue samples, respectively. Constitutive expressions of MEK2 and phosphorylated MEK (p-MEK) were observed in PC-1.0 and ASPC-1 cells, which exhibited a growth pattern of single cells, whereas the relevant expressions were quite faint in PC-1 cells and CAPAN-2 cells, which exhibited a growth pattern of island-like clonies. Simultaneous inductions of MEK2 expressions and cell dissociation were observed after the treatment with a conditioned medium (CM) of PC-1.0 cells. The expression of MEK2 and p-MEK were reduced and the cell aggregation was found in PC-1.0 and ASPC-1 cells after U0126 (a MEK inhibitor) treatment. In vivo, both the MEK2 and p-MEK overexpressed in human pancreatic cancer tissues and p-MEK was found to be more strongly expressed in the invasive front than that in the center of tumor (Pcell dissociation. MEK2 activation is probably involved in the first step of the cascade in the invasion-metastasis of pancreatic cancer.

  9. Mesothelioma Cells Escape Heat Stress by Upregulating Hsp40/Hsp70 Expression via Mitogen-Activated Protein Kinases

    Directory of Open Access Journals (Sweden)

    Michael Roth

    2009-01-01

    Full Text Available Therapy with hyperthermal chemotherapy in pleural diffuse malignant mesothelioma had limited benefits for patients. Here we investigated the effect of heat stress on heat shock proteins (HSP, which rescue tumour cells from apoptosis. In human mesothelioma and mesothelial cells heat stress (39–42°C induced the phosphorylation of two mitogen activated kinases (MAPK Erk1/2 and p38, and increased Hsp40, and Hsp70 expression. Mesothelioma cells expressed more Hsp40 and were less sensitive to heat stress compared to mesothelial cells. Inhibition of Erk1/2 MAPK by PD98059 or by Erk1 siRNA down-regulated heat stress-induced Hsp40 and Hsp70 expression and reduced mesothelioma cell survival. Inhibition of p38MAPK by SB203580 or siRNA reduced Hsp40, but not Hsp70, expression and also increased mesothelioma cell death. Thus hyperthermia combined with suppression of p38 MAPK or Hsp40 may represent a novel approach to improve mesothelioma therapy.

  10. Mitogenic activation of B cells in vitro: the properties of adherent accessory cells as revealed by partition analysis

    International Nuclear Information System (INIS)

    Kettman, J.R.; Soederberg, A.; Lefkovits, I.

    1986-01-01

    The requirement of B cells activated by mitogen (dextran sulfate plus lipopolysaccharide) for accessory cells was studied by partition analysis. Small numbers of splenic B cells were activated to clonal growth, as determined by visual inspection, and to immunoglobulin (Ig) synthesis, as determined by release of Ig into the culture fluid. By placing irradiated adherent cells in the periphery of the microculture wells and forcing responding cells to different areas of the well (slant experiments), it was observed that no cell contact was necessary for B cell activation, and that promoted contact (Rock and Roll experiments) does not increase the efficiency of activation. Sequential microcultures suggest that only some irradiated adherent cells act as accessory cells, but they can perform this function to more than one B cell. Attempts to perform limiting dilution analysis by varying irradiated adherent cell input showed non-single-hit behavior. When the data were rearranged, taking into account the distribution of irradiated adherent cells, then single-hit behavior with about 1 to 5% of irradiated adherent cells acting as an accessory cells for B cell clonal activation was observed. The evidence suggests that an uncommon irradiated adherent cell releases a soluble factor necessary for B cell activation and/or clonal proliferation

  11. Hub nodes in the network of human Mitogen-Activated Protein Kinase (MAPK pathways: Characteristics and potential as drug targets

    Directory of Open Access Journals (Sweden)

    V.K. MD Aksam

    2017-01-01

    Full Text Available Proteins involved in the cross-talk between ERK1/2, ERK5, JNK, and P38 signalling pathways integrate the network of Mitogen-Activated Protein Kinase (MAPK pathways. Graph theory-based approach is used to construct the network of MAPK pathways, and to observe the network organisational principles. Connectivity pattern reveals rich-club among the hubs, enabling structural ordering. A positive correlation between the degree of the nodes and percentage of essential protein showed hubs are central to the network architecture and function. Furthermore, attributes like connectivity, inter/intra-pathway class, position in the pathway, protein type and subcellular localization of the essential and non-essential proteins are characterizing complex functional roles. Shared properties of 34 cancerous essential proteins lack to be drug targets. We identified the seven nodes overlapping properties of the hub, essential and causing side effects on targeting them. We exploit the strategy of cancerous, non-hub and non-essential proteins as potential drug targets and identified 4EBP1, BAD, CHOP10, GADD45, HSP27, MKP1, RNPK, MLTKa/b, cPLA2, eEF2K and elF4E. We have illustrated the implication of targeting hub nodes and proposed network-based drug targets which would cause less side effect.

  12. Reduced response of splenocytes after mitogen-stimulation in the prion protein (PrP) gene-deficient mouse: PrPLP/Doppel production and cerebral degeneration

    International Nuclear Information System (INIS)

    Kim, Chi-Kyeong; Hirose, Yuko; Sakudo, Akikazu; Takeyama, Natsumi; Kang, Chung-Boo; Taniuchi, Yojiro; Matsumoto, Yoshitsugu; Itohara, Shigeyoshi; Sakaguchi, Suehiro; Onodera, Takashi

    2007-01-01

    Splenocytes of wild-type (Prnp +/+ ) and prion protein gene-deficient (Prnp -/- ) mice were treated with various activation stimuli such as T cell mitogen concanavalin A (ConA), phorbol 12-myristate 13-acetate (PMA) + ionomycin (Io), or B cell mitogen lipopolysaccharide (LPS). Cellular prion protein (PrP C ) expression was enhanced following ConA stimulation, but not PMA + Io or LPS in Prnp +/+ splenocytes. Rikn Prnp -/- splenocytes elicited lower cell proliferations than Prnp +/+ or Zrch I Prnp -/- splenocytes after LPS stimulation and showed sporadic nerve cells in the cerebral cortex and deeper structure. Around the degenerated nerve cells, mild vacuolation in the neuropil was observed. This neural alteration correlated well to the suppressed response of B cells in the spleen. The finding that discrete lesions within the central nervous systems induced marked modulation of immune function probably indicates the existence of a delicately balanced neural-endocrine network by PrP C and PrPLP/Doppel

  13. Proliferation and mitogenic response to PDGF-BB of fibroblasts isolated from chronic venous leg ulcers is ulcer-age dependent

    DEFF Research Database (Denmark)

    Agren, M S; Steenfos, H H; Dabelsteen, S

    1999-01-01

    Several pathophysiologic mechanisms have been proposed to explain slow-healing leg ulcers, but little is known about the growth behavior of cells in these wounds. Platelet-derived growth factor-BB applied topically to chronic wounds has shown beneficial effects, although the effects have been less...... pronounced than would have been expected based on studies on acute wounds. The objective of this study was to compare fibroblasts in culture obtained from chronic wounds (non-healing chronic venous leg ulcers), acute wounds and normal dermis regarding growth, mitogenic response to platelet-derived growth...... from the oldest chronic wounds deviated substantially from those of acute wounds and normal dermis, and resembled in vitro aged or senescent fibroblasts. Mitogenic response of chronic wound fibroblasts to human recombinant platelet-derived growth factor-BB was also reduced with ulcer age...

  14. Evidence of a New Role for the High-Osmolarity Glycerol Mitogen-Activated Protein Kinase Pathway in Yeast: Regulating Adaptation to Citric Acid Stress†

    OpenAIRE

    Lawrence, Clare L.; Botting, Catherine H.; Antrobus, Robin; Coote, Peter J.

    2004-01-01

    Screening the Saccharomyces cerevisiae disruptome, profiling transcripts, and determining changes in protein expression have identified an important new role for the high-osmolarity glycerol (HOG) mitogen-activated protein kinase (MAPK) pathway in the regulation of adaptation to citric acid stress. Deletion of HOG1, SSK1, PBS2, PTC2, PTP2, and PTP3 resulted in sensitivity to citric acid. Furthermore, citric acid resulted in the dual phosphorylation, and thus activation, of Hog1p. Despite mino...

  15. UVB-mediated activation of p38 mitogen-activated protein kinase enhances resistance of normal human keratinocytes to apoptosis by stabilizing cytoplasmic p53.

    OpenAIRE

    Chouinard, Nadine; Valerie, Kristoffer; Rouabhia, Mahmoud; Huot, Jacques

    2002-01-01

    Human keratinocytes respond to UV rays by developing a fast adaptive response that contributes to maintaining their functions and survival. We investigated the role of the mitogen-activated protein kinase pathways in transducing the UV signals in normal human keratinocytes. We found that UVA, UVB or UVC induced a marked and persistent activation of p38, whereas c-Jun N-terminal kinase or extracellular signal-regulated kinase were less or not activated respectively. Inhibition of p38 activity ...

  16. The down-regulation of the mitogenic fibrinogen receptor (MFR) in serum-containing medium does not occur in defined medium.

    Science.gov (United States)

    Levesque, J P; Hatzfeld, A; Domart, I; Hatzfeld, J

    1990-02-01

    Normal human hemopoietic cells such as early bone marrow progenitors, or lymphoma-derived cell lines such as Raji or JM cells, possess a low-affinity receptor specific for fibrinogen. This receptor triggers a mitogenic effect. It differs from the glycoprotein IIb-IIIa which is involved in fibrinogen-induced platelet aggregation. We demonstrate here that this mitogenic fibrinogen receptor (MFR) can be internalized or reexpressed, depending on culture conditions. Internalization was temperature-dependent. At 37 degrees C in the presence of cycloheximide or actinomycin D, the half-life of cell surface MFRs was 2 h, independent of receptor occupancy. Binding of fibrinogen to the MFR resulted in a down-regulation which was fibrinogen dose-dependent. This occurred in serum-supplemented medium but not in defined medium supplemented with fatty acids. Reexpression of MFRs could be induced in 28 to 42 h by serum removal. The down-regulation of mitogenic receptors in plasma or serum could explain why normal cells do not proliferate in the peripheral blood.

  17. Distinct effects of cAMP and mitogenic signals on CREB-binding protein recruitment impart specificity to target gene activation via CREB

    Science.gov (United States)

    Mayr, Bernhard M.; Canettieri, Gianluca; Montminy, Marc R.

    2001-01-01

    Ser-133 phosphorylation of the cAMP-responsive element-binding protein (CREB) is sufficient to induce cellular gene expression in response to cAMP, but additional promoter-bound factors are required for target gene activation by CREB in response to mitogen/stress signals. To compare the relative effects of different signals on recruitment of the coactivator CREB-binding protein (CBP) to CREB in living cells, we developed a fluorescence resonance energy transfer (FRET) assay. cAMP promoted the interaction of CREB with CBP in a phosphorylation-dependent manner by FRET analysis, but mitogen/stress signals were far less effective in stimulating complex formation even though they induced comparable levels of Ser-133 phosphorylation. cAMP and non-cAMP stimuli were comparably active in promoting this interaction in the cytosol; the formation of CREB⋅CBP complexes in response to non-cAMP signals was specifically inhibited in the nucleus. Non-cAMP signals had no effect on intrinsic CREB- or CBP-binding activities by Far Western blot assay, thereby supporting the presence of a distinct CREB⋅CBP antagonist. Our studies indicate that the relative effects of cAMP and mitogen/stress signals on CREB⋅CBP complex formation impart selectivity to gene activation through CREB phosphorylated at Ser-133. PMID:11535812

  18. Roles of PU.1 in monocyte- and mast cell-specific gene regulation: PU.1 transactivates CIITA pIV in cooperation with IFN-gamma.

    Science.gov (United States)

    Ito, Tomonobu; Nishiyama, Chiharu; Nakano, Nobuhiro; Nishiyama, Makoto; Usui, Yoshihiko; Takeda, Kazuyoshi; Kanada, Shunsuke; Fukuyama, Kanako; Akiba, Hisaya; Tokura, Tomoko; Hara, Mutsuko; Tsuboi, Ryoji; Ogawa, Hideoki; Okumura, Ko

    2009-07-01

    Over-expression of PU.1, a myeloid- and lymphoid-specific transcription factor belonging to the Ets family, induces monocyte-specific gene expression in mast cells. However, the effects of PU.1 on each target gene and the involvement of cytokine signaling in PU.1-mediated gene expression are largely unknown. In the present study, PU.1 was over-expressed in two different types of bone marrow-derived cultured mast cells (BMMCs): BMMCs cultured with IL-3 plus stem cell factor (SCF) and BMMCs cultured with pokeweed mitogen-stimulated spleen-conditioned medium (PWM-SCM). PU.1 over-expression induced expression of MHC class II, CD11b, CD11c and F4/80 on PWM-SCM-cultured BMMCs, whereas IL-3/SCF-cultured BMMCs expressed CD11b and F4/80, but not MHC class II or CD11c. When IFN-gamma was added to the IL-3/SCF-based medium, PU.1 transfectant acquired MHC class II expression, which was abolished by antibody neutralization or in Ifngr(-/-) BMMCs, through the induction of expression of the MHC class II transactivator, CIITA. Real-time PCR detected CIITA mRNA driven by the fourth promoter, pIV, and chromatin immunoprecipitation indicated direct binding of PU.1 to pIV in PU.1-over-expressing BMMCs. PU.1-over-expressing cells showed a marked increase in IL-6 production in response to LPS stimulation in both IL-3/SCF and PWM-SCM cultures. These results suggest that PU.1 overproduction alone is sufficient for both expression of CD11b and F4/80 and for amplification of LPS-induced IL-6 production. However, IFN-gamma stimulation is essential for PU.1-mediated transactivation of CIITA pIV. Reduced expression of mast cell-related molecules and transcription factors GATA-1/2 and up-regulation of C/EBPalpha in PU.1 transfectants indicate that enforced PU.1 suppresses mast cell-specific gene expression through these transcription factors.

  19. Three mitogen-activated protein kinases required for cell wall integrity contribute greatly to biocontrol potential of a fungal entomopathogen.

    Directory of Open Access Journals (Sweden)

    Ying Chen

    Full Text Available Bck1, Mkk1 and Slt2 are three mitogen-activated protein (MAP kinases constituting cell wall integrity (CWI pathway that may control multi-stress responses via crosstalk with high-osmolarity glycerol (HOG pathway in budding yeast. In this study, Bck1, Mkk1 and Slt2 orthologues in Beauveria bassiana were confirmed as the three-module cascade essential for CWI because cell wall impairment occurred in the hyphae and conidia of Δbck1, Δmkk1 and Δslt2 examined in multiple experiments. Strikingly, all the deletion mutants became more sensitive to hyperosmotic NaCl and sorbitol with the Western blot of Hog1 phosphorylation being weakened in Δbck1 and absent in Δmkk1 and Δslt2. Apart from crossing responses to cell wall perturbation and high osmolarity, three deletion mutants exhibited faster growth and conidiation on nutrition-rich medium, much less virulence to Galleria mellonella larvae, and higher sensitivity to nutritional, fungicidal, thermal and UV-B irradiative stresses, accompanied with less accumulation of intracellular mannitol and trehalose. Moreover, Δmkk1 and Δslt2 were equally more sensitive to all the stresses of different types except wet-heat stress than wild type and more or less different from Δbck1 in sensitivity to most of the stresses despite their null responses to two oxidants. All the changes in three deletion mutants were restored by each targeted gene complementation. Taken together, the CWI-required Bck1, Mkk1 and Slt2 are all positive, but differential, regulators of multi-stress tolerance and virulence perhaps due to interplay with the HOG pathway essential for osmoregulation, thereby contributing greatly to the biocontrol potential of the fungal entomopathogen.

  20. Mitogen activated protein kinase phosphatase-1 prevents the development of tactile sensitivity in a rodent model of neuropathic pain

    Directory of Open Access Journals (Sweden)

    Ndong Christian

    2012-04-01

    Full Text Available Abstract Background Neuropathic pain due to nerve injury is one of the most difficult types of pain to treat. Following peripheral nerve injury, neuronal and glial plastic changes contribute to central sensitization and perpetuation of mechanical hypersensitivity in rodents. The mitogen activated protein kinase (MAPK family is pivotal in this spinal cord plasticity. MAPK phosphatases (MKPs limit inflammatory processes by dephosphorylating MAPKs. For example, MKP-1 preferentially dephosphorylates p-p38. Since spinal p-p38 is pivotal for the development of chronic hypersensitivity in rodent models of pain, and p-p38 inhibitors have shown clinical potential in acute and chronic pain patients, we hypothesize that induction of spinal MKP-1 will prevent the development of peripheral nerve-injury-induced hypersensitivity and p-p38 overexpression. Results We cloned rat spinal cord MKP-1 and optimize MKP-1 cDNA in vitro using transfections to BV-2 cells. We observed that in vitro overexpression of MKP-1 blocked lipopolysaccharide-induced phosphorylation of p38 (and other MAPKs as well as release of pro-algesic effectors (i.e., cytokines, chemokines, nitric oxide. Using this cDNA MKP-1 and a non-viral, in vivo nanoparticle transfection approach, we found that spinal cord overexpression of MKP-1 prevented development of peripheral nerve-injury-induced tactile hypersensitivity and reduced pro-inflammatory cytokines and chemokines and the phosphorylated form of p38. Conclusions Our results indicate that MKP-1, the natural regulator of p-p38, mediates resolution of the spinal cord pro-inflammatory milieu induced by peripheral nerve injury, resulting in prevention of chronic mechanical hypersensitivity. We propose that MKP-1 is a potential therapeutic target for pain treatment or prevention.

  1. Identification and functional analysis of mitogen-activated protein kinase kinase kinase (MAPKKK) genes in canola (Brassica napus L.).

    Science.gov (United States)

    Sun, Yun; Wang, Chen; Yang, Bo; Wu, Feifei; Hao, Xueyu; Liang, Wanwan; Niu, Fangfang; Yan, Jingli; Zhang, Hanfeng; Wang, Boya; Deyholos, Michael K; Jiang, Yuan-Qing

    2014-05-01

    Mitogen-activated protein kinase (MAPK) signalling cascades, consisting of three types of reversibly phosphorylated kinases (MAPKKK, MAPKK, and MAPK), are involved in important processes including plant immunity and hormone responses. The MAPKKKs comprise the largest family in the MAPK cascades, yet only a few of these genes have been associated with physiological functions, even in the model plant Arabidopsis thaliana. Canola (Brassica napus L.) is one of the most important oilseed crops in China and worldwide. To explore MAPKKK functions in biotic and abiotic stress responses in canola, 66 MAPKKK genes were identified and 28 of them were cloned. Phylogenetic analysis of these canola MAPKKKs with homologous genes from representative species classified them into three groups (A-C), comprising four MAPKKKs, seven ZIKs, and 17 Raf genes. A further 15 interaction pairs between these MAPKKKs and the downstream BnaMKKs were identified through a yeast two-hybrid assay. The interactions were further validated through bimolecular fluorescence complementation (BiFC) analysis. In addition, by quantitative real-time reverse transcription-PCR, it was further observed that some of these BnaMAPKKK genes were regulated by different hormone stimuli, abiotic stresses, or fungal pathogen treatments. Interestingly, two novel BnaMAPKKK genes, BnaMAPKKK18 and BnaMAPKKK19, which could elicit hypersensitive response (HR)-like cell death when transiently expressed in Nicotiana benthamiana leaves, were successfully identified. Moreover, it was found that BnaMAPKKK19 probably mediated cell death through BnaMKK9. Overall, the present work has laid the foundation for further characterization of this important MAPKKK gene family in canola.

  2. The p38α mitogen-activated protein kinase is a key regulator of myelination and remyelination in the CNS.

    Science.gov (United States)

    Chung, S-H; Biswas, S; Selvaraj, V; Liu, X-B; Sohn, J; Jiang, P; Chen, C; Chmilewsky, F; Marzban, H; Horiuchi, M; Pleasure, D E; Deng, W

    2015-05-07

    The p38α mitogen-activated protein kinase (MAPK) is one of the serine/threonine kinases regulating a variety of biological processes, including cell-type specification, differentiation and migration. Previous in vitro studies using pharmacological inhibitors suggested that p38 MAPK is essential for oligodendrocyte (OL) differentiation and myelination. To investigate the specific roles of p38α MAPK in OL development and myelination in vivo, we generated p38α conditional knockout (CKO) mice under the PLP and nerve/glial antigen 2 (NG2) gene promoters, as these genes are specifically expressed in OL progenitor cells (OPCs). Our data revealed that myelin synthesis was completely inhibited in OLs differentiated from primary OPC cultures derived from the NG2 Cre-p38α CKO mouse brains. Although an in vivo myelination defect was not obvious after gross examination of these mice, electron microscopic analysis showed that the ultrastructure of myelin bundles was severely impaired. Moreover, the onset of myelination in the corpus callosum was delayed in the knockout mice compared with p38α fl/fl control mice. A delay in OL differentiation in the central nervous system was observed with concomitant downregulation in the expression of OPC- and OL-specific genes such as Olig1 and Zfp488 during early postnatal development. OPC proliferation was not affected during this time. These data indicate that p38α is a positive regulator of OL differentiation and myelination. Unexpectedly, we observed an opposite effect of p38α on remyelination in the cuprizone-induced demyelination model. The p38α CKO mice exhibited better remyelination capability compared with p38α fl/fl mice following demyelination. The opposing roles of p38α in myelination and remyelination could be due to a strong anti-inflammatory effect of p38α or a dual reciprocal regulatory action of p38α on myelin formation during development and on remyelination after demyelination.

  3. Runx expression is mitogenic and mutually linked to Wnt activity in blastula-stage sea urchin embryos.

    Directory of Open Access Journals (Sweden)

    Anthony J Robertson

    Full Text Available The Runt homology domain (Runx defines a metazoan family of sequence-specific transcriptional regulatory proteins that are critical for animal development and causally associated with a variety of mammalian cancers. The sea urchin Runx gene SpRunt-1 is expressed throughout the blastula stage embryo, and is required globally during embryogenesis for cell survival and differentiation.Depletion of SpRunt-1 by morpholino antisense-mediated knockdown causes a blastula stage deficit in cell proliferation, as shown by bromodeoxyuridine (BrdU incorporation and direct cell counts. Reverse transcription coupled polymerase chain reaction (RT-PCR studies show that the cell proliferation deficit is presaged by a deficit in the expression of several zygotic wnt genes, including wnt8, a key regulator of endomesoderm development. In addition, SpRunt-1-depleted blastulae underexpress cyclinD, an effector of mitogenic Wnt signaling. Blastula stage cell proliferation is also impeded by knockdown of either wnt8 or cyclinD. Chromatin immunoprecipitation (ChIP indicates that Runx target sites within 5' sequences flanking cyclinD, wnt6 and wnt8 are directly bound by SpRunt-1 protein at late blastula stage. Furthermore, experiments using a green fluorescent protein (GFP reporter transgene show that the blastula-stage operation of a cis-regulatory module previously shown to be required for wnt8 expression (Minokawa et al., Dev. Biol. 288: 545-558, 2005 is dependent on its direct sequence-specific interaction with SpRunt-1. Finally, inhibitor studies and immunoblot analysis show that SpRunt-1 protein levels are negatively regulated by glycogen synthase kinase (GSK-3.These results suggest that Runx expression and Wnt signaling are mutually linked in a feedback circuit that controls cell proliferation during development.

  4. p38 mitogen-activated protein kinase is activated and linked to TNF-alpha signaling in inflammatory bowel disease.

    Science.gov (United States)

    Waetzig, Georg H; Seegert, Dirk; Rosenstiel, Philip; Nikolaus, Susanna; Schreiber, Stefan

    2002-05-15

    Inflammatory bowel diseases (IBD)--Crohn's disease and ulcerative colitis--are relapsing chronic inflammatory disorders which involve genetic, immunological, and environmental factors. The regulation of TNF-alpha, a key mediator in the inflammatory process in IBD, is interconnected with mitogen-activated protein kinase pathways. The aim of this study was to characterize the activity and expression of the four p38 subtypes (p38alpha-delta), c-Jun N-terminal kinases (JNKs), and the extracellular signal-regulated kinases (ERK)1/2 in the inflamed intestinal mucosa. Western blot analysis revealed that p38alpha, JNKs, and ERK1/2 were significantly activated in IBD, with p38alpha showing the most pronounced increase in kinase activity. Protein expression of p38 and JNK was only moderately altered in IBD patients compared with normal controls, whereas ERK1/2 protein was significantly down-regulated. Immunohistochemical analysis of inflamed mucosal biopsies localized the main expression of p38alpha to lamina propria macrophages and neutrophils. ELISA screening of the supernatants of Crohn's disease mucosal biopsy cultures showed that incubation with the p38 inhibitor SB 203580 significantly reduced secretion of TNF-alpha. In vivo inhibition of TNF-alpha by a single infusion of anti-TNF-alpha Ab (infliximab) resulted in a highly significant transient increase of p38alpha activity during the first 48 h after infusion. A significant infliximab-dependent p38alpha activation was also observed in THP-1 myelomonocytic cells. In human monocytes, infliximab enhanced TNF-alpha gene expression, which could be inhibited by SB 203580. In conclusion, p38alpha signaling is involved in the pathophysiology of IBD.

  5. High Cell Density Upregulates Calcium Oscillation by Increasing Calcium Store Content via Basal Mitogen-Activated Protein Kinase Activity.

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Morita

    Full Text Available Calcium releases of non-excitable cells are generally a combination of oscillatory and non-oscillatory patterns, and factors affecting the calcium dynamics are still to be determined. Here we report the influence of cell density on calcium increase patterns of clonal cell lines. The majority of HeLa cells seeded at 1.5 x 104/cm2 showed calcium oscillations in response to histamine and ATP, whereas cells seeded at 0.5 x 104/cm2 largely showed transient and sustained calcium increases. Cell density also affected the response of HEK293 cells to ATP in a similar manner. High cell density increased the basal activity of the mitogen-activated protein (MAP kinase and calcium store content, and both calcium oscillation and calcium store content were down-regulated by a MAP kinase inhibitor, U0126. Thus, MAP kinase-mediated regulation of calcium store likely underlie the effect of cell density on calcium oscillation. Calcium increase patterns of HeLa cells were conserved at any histamine concentrations tested, whereas the overexpression of histamine H1 receptor, which robustly increased histamine-induced inositol phospholipid hydrolysis, converted calcium oscillations to sustained calcium increases only at high histamine concentrations. Thus, the consequence of modulating inositol phospholipid metabolism was distinct from that of changing cell density, suggesting the effect of cell density is not attributed to inositol phospholipid metabolism. Collectively, our results propose that calcium increase patterns of non-excitable cells reflect calcium store, which is regulated by the basal MAP kinase activity under the influence of cell density.

  6. Involvement of a novel p38 mitogen-activated protein kinase in larval metamorphosis of the polychaete Hydroides elegans (Haswell)

    KAUST Repository

    Wang, Hao

    2010-04-19

    Hydroides elegans is a common marine fouling organism in most tropical and subtropical waters. The life cycle of H. elegans includes a planktonic larval stage in which swimming larvae normally take 5 days to attain competency to settle. Larval metamorphosis marks the beginning of its benthic life; however, the endogenous molecular mechanisms that regulate metamorphosis remain largely unknown. In this study, a PCR-based suppressive subtractive hybridization (SSH) library was constructed to screen the genes expressed in competent larvae but not in precompetent larvae. Among the transcripts isolated from the library, 21 significantly matched sequences in the GenBank. Many of these isolated transcripts have putative roles in the reactive oxygen species (ROS) signal transduction pathway or in response to ROS stress. A putative novel p38 mitogen-activated protein kinase (MAPK), which was also isolated with SSH screen, was then cloned and characterized. The MAPK inhibitors assay showed that both p38 MAPK inhibitors SB202190 and SB203580 effectively inhibited the biofilm-induced metamorphosis of H. elegans. A cell stressors assay showed that H2O2 effectively induced larval metamorphosis of H. elegans, but the inductivity of H2O2 was also inhibited by both SB inhibitors. The catalase assay showed that the catalase could effetely inhibit H. elegans larvae from responding to inductive biofilm. These results showed that the p38 MAPK-dependent pathway plays critical role in controlling larval metamorphosis of the marine polychaete H. elegans, and the reactive oxygen radicals produced by biofilm could be the cue inducing larval metamorphosis. © 2010 Wiley-Liss, Inc.

  7. T cell activation and proliferation following acute exercise in human subjects is altered by storage conditions and mitogen selection.

    Science.gov (United States)

    Siedlik, Jacob A; Deckert, Jake A; Benedict, Stephen H; Bhatta, Anuja; Dunbar, Amanda J; Vardiman, John P; Gallagher, Philip M

    2017-07-01

    Recent work investigating exercise induced changes in immunocompetence suggests that some of the ambiguity in the literature is resultant from different cell isolation protocols and mitogen selection. To understand this effect, we compared post-exercise measures of T cell activation and proliferation using two different stimulation methods (costimulation through CD28 or stimulation with phytohaemagglutinin [PHA]). Further, we investigated whether exercise induced changes are maintained when T cell isolation from whole blood is delayed overnight in either a room temperature or chilled (4°C) environment. As expected, an increased proliferation response was observed post-exercise in T cells isolated from whole blood of previously trained individuals immediately after blood collection. Also, cells stimulated with PHA after resting overnight in whole blood were not adversely impacted by the storage conditions. In contrast, allowing cells to rest overnight in whole blood prior to stimulation through CD28, lessened the proliferation observed by cells following exercise rendering both the room temperature and chilled samples closer to the results seen in the control condition. Changes in early markers of activation (CD25), followed a similar pattern, with activation in PHA stimulated cells remaining fairly robust after overnight storage; whereas cell activation following stimulation through CD3+CD28 was disproportionately decreased by the influence of overnight storage. These findings indicate that decisions regarding cell stimulation methods need to be paired with the timeline for T cell isolation from whole blood. These considerations will be especially important for field based studies of immunocompetence where there is a delay in getting whole blood samples to a lab for processing as well as clinical applications where a failure to isolate T cells in a timely manner may result in loss of the response of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. TMPYP4 exerted antitumor effects in human cervical cancer cells through activation of p38 mitogen-activated protein kinase.

    Science.gov (United States)

    Cheng, Ming-Jun; Cao, Yun-Gui

    2017-07-03

    The aim of the present study was to investigate the potential effects of the 5,10,15,20-tetrakis (1-methylpyridinium-4-yl) porphyrin (TMPyP4) on the proliferation and apoptosis of human cervical cancer cells and the underlying mechanisms by which TMPyP4 exerted its actions. After human cervical cancer cells were treated with different doses of TMPyP4, cell viability was determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) method, the apoptosis was observed by flow cytometry (FCM), and the expression of p38 mitogen-activated protein kinase (MAPK), phosphated p38 MAPK (p-p38 MAPK), capase-3, MAPKAPK2 (MK-2) and poly ADP-ribose polymerase (PARP) was measured by Western blot analysis. The analysis revealed that TMPyP4 potently suppressed cell viability and induced the apoptosis of human cervical cancer cells in a dose-dependent manner. In addition, the up-regulation of p-p38 MAPK expression levels was detected in TMPyP4-treated human cervical cancer cells. However, followed by the block of p38 MAPK signaling pathway using the inhibitor SB203580, the effects of TMPyP4 on proliferation and apoptosis of human cervical cancer cells were significantly changed. It was indicated that TMPyP4-inhibited proliferation and -induced apoptosis in human cervical cancer cells was accompanied by activating the p38 MAPK signaling pathway. Taken together, our study demonstrates that TMPyP4 may represent a potential therapeutic method for the treatment of cervical carcinoma.

  9. Effects of p38 mitogen-activated protein kinase on lung ischemia-reperfusion injury in diabetic rats.

    Science.gov (United States)

    Song, Linlin; Li, Di; Wang, Juan; Meng, Chao; Cui, Xiaoguang

    2017-08-01

    Lung ischemia-reperfusion injury (LIRI) is a pathologic process that is observed in several clinical conditions, and p38 mitogen-activated protein kinase (MAPK) is involved. Diabetes mellitus (DM) results in an increased incidence of ischemia-induced organ damage. The aims of this study were to examine the effects of DM on LIRI in a rat model of DM and to explore the possible mechanisms in relation to the p38 MAPK pathway. Forty rats were randomly divided into the following five groups (n = 8 each): a control + sham group, a control + IR group (CIR), a DM + sham group, a DM + IR group (DIR), and a DM + IR + SB203580 group. The control and streptozotocin-induced diabetic rats underwent a sham operation or left hilum occlusion for 90 min followed by reperfusion for 4 h. SB203580 was used to inhibit the p38 MAPK pathway. The pulmonary oxygenation index, inflammatory cytokines in the serum, lung edema, histopathology, oxidant stress, apoptosis, and phosphorylated/total-p38 MAPK protein levels were measured. The DIR group displayed greater concentrations of tumor necrosis factor-α, interleukin-6, and intercellular adhesion molecule-1 and increases in the wet weight-to-dry weight ratio, lung injury scores, malondialdehyde levels, and cellular apoptosis, and these effects were accompanied by lower pulmonary oxygenation compared with the CIR group (P < 0.05). In the DIR group, the expression levels of p38 MAPK protein were significantly upregulated compared with those of the CIR group. Additionally, all of these alterations were attenuated in the DM + IR + SB203580 group compared with the DIR group. Diabetes exacerbates LIRI by activating the p38 MAPK pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Involvement of p38 mitogen-activated protein kinase in acquired gemcitabine-resistant human urothelial carcinoma sublines

    Directory of Open Access Journals (Sweden)

    Yu-Ting Kao

    2014-07-01

    Full Text Available Resistance to chemotherapeutic drugs is one of the major challenges in the treatment of cancer. A better understanding of how resistance arises and what molecular alterations correlate with resistance is the key to developing novel effective therapeutic strategies. To investigate the underlying mechanisms of gemcitabine (Gem resistance and provide possible therapeutic options, three Gem-resistant urothelial carcinoma sublines were established (NG0.6, NG0.8, and NG1.0. These cells were cross-resistant to arabinofuranosyl cytidine and cisplatin, but sensitive to 5-fluorouracil. The resistant cells expressed lower values of [hENT1 × dCK/RRM1 × RRM2] mRNA ratio. Two adenosine triphosphate-binding cassette proteins ABCD1 as well as multidrug resistance protein 1 were elevated. Moreover, cyclin D1, cyclin-dependent kinases 2 and 4 were upregulated, whereas extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase (MAPK activity were repressed significantly. Administration of p38 MAPK inhibitor significantly reduced the Gem sensitivity in NTUB1 cells, whereas that of an extracellular signal-regulated kinase MAPK inhibitor did not. Furthermore, the Gem-resistant sublines also exhibited higher migration ability. Forced expression of p38 MAPK impaired the cell migration activity and augmented Gem sensitivity in NG1.0 cells. Taken together, these results demonstrate that complex mechanisms were merged in acquiring Gem resistance and provide information that can be important for developing therapeutic targets for treating Gem-resistant tumors.

  11. Activation of ZmMKK10, a maize mitogen-activated protein kinase kinase, induces ethylene-dependent cell death.

    Science.gov (United States)

    Chang, Ying; Yang, Hailian; Ren, Dongtao; Li, Yuan

    2017-11-01

    Mitogen-activated protein kinase (MAPK) cascades play important roles in regulating plant growth, development and stress responses. Here, we report that ZmMKK10, a maize MAP kinase kinase, positively regulates cell death. Sequence comparison to Arabidopsis MKKs has led to ZmMKK10 being classified as a group D MKK. Kinase activity analysis of recombinant ZmMKK10 showed that the Mg 2+ ion was required for its kinase activity. Transient expression of ZmMKK10 WT or ZmMKK10 DD (the active form of ZmMKK10) in maize mesophyll protoplast significantly increased the cell death rate. Inducible expression of ZmMKK10 WT or ZmMKK10 DD in Arabidopsis transgenic plants caused rapid HR-like cell death, whereas induction of ZmMKK10 KR (the inactive form of ZmMKK10) expression in transgenic plants did not yield the same phenotype. Genetic and pharmacological analysis revealed that ZmMKK10-induced cell death in transgenic plants requires the activation of Arabidopsis MPK3 and MPK6 and that it partially depended on ethylene biosynthesis. ZmMPK3 and ZmMPK7, the orthologues of Arabidopsis MPK3 and MPK6, interacted with ZmMKK10 in yeast and ZmMKK10 phosphorylated them both in vitro. Our results demonstrate that ZmMKK10 induces cell death in an ethylene-dependent manner. Furthermore, ZmMPK3 and ZmMPK7 may be the downstream MAPKs in this process. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Effect of chloroquine on human lymphocyte proliferation

    DEFF Research Database (Denmark)

    Bygbjerg, Ib Christian; Flachs, H

    1986-01-01

    the response to pokeweed mitogen. The response to concanavalin A and to various antigens was suppressed, especially the response to large particulate antigens. Oral intake of 300 mg of chloroquine base/week did not affect the lymphocyte proliferative responses. 600 mg of base/week decreased the response...

  13. B and T lymphocytes in man. I. Effect of infant thymic irradiation on the circulating B and T lymphocytes

    International Nuclear Information System (INIS)

    Reddy, M.M.; Goh, K.; Hempelmann, L.H.

    1976-01-01

    B and T lymphocytes were studied in a group of adults whose thymic glands were irradiated in infancy for alleged thymic enlargement. Two independent methods were used to determine the B and T lymphocytes from each peripheral blood specimen: (1) the relative proportion of cells with surface immunoglobulins (B lymphocytes) and cells forming rosettes with sheep erythrocytes (T lymphocytes); and (2) the relative mitogenic response to phytohemagglutinin (T lymphocytes) and to pokeweed mitogen (B lymphocytes). All specimens were coded. The results obtained indicate: (1) a reduction of B and T lymphocytes; and (2) a decreased mitogenic response of lymphocytes to phytohemagglutinin and pokeweed mitogen in this group of patients as compared with the controls. These observations suggest that (1) the effect of irradiation to the thymus gland on lymphocytes is long lasting and (2) both B and T lymphocytes are affected by irradiation to the thymus gland

  14. Signals involved in T cell activation. I. Phorbol esters enhance responsiveness but cannot replace intact accessory cells in the induction of mitogen-stimulated T cell proliferation

    International Nuclear Information System (INIS)

    Davis, L.; Lipsky, P.E.

    1985-01-01

    The role of accessory cells (AC) in the initiation of mitogen-induced T cell proliferation was examined by comparing the effect of intact macrophages (M phi) with that of 4-β-phorbol 12-myristate 13-acetate (PMA). In high-density cultures, purified guinea pig T cells failed to proliferate in response to stimulation with phytohemagglutinin (PHA), concanavalin A (Con A), or PMA alone. The addition of M phi to PHA or Con A but not PMA-stimulated cultures restored T cell proliferation. The addition of PMA to high-density T cell cultures stimulated with PHA or Con A also permitted [ 3 H]thymidine incorporation, but was less effective than intact M phi in this regard. This action of PMA was dependent on the small number of Ac contaminating the T cell cultures as evidenced by the finding that PMA could not support mitogen responsiveness of T cells that had been depleted of Ia-bearing cells by panning, even when these cells were cultured at high density. A low-density culture system was used to examine in greater detail the possibility that PMA could completely substitute for M phi in promoting T cells activation. In low-density cultures, mitogen-induced T cell proliferation required intact M phi. These results support a model of T cell activation in which AC play at least two distinct roles. The initiation of the response requires a signal conveyed by an intact M phi, which cannot be provided by either a M phi supernatant factor or PMA. The response can be amplified by additional M phi or M phi supernatant factors. PMA can substitute for M phi in this regard and can provide the signal necessary for amplification of T cell proliferation supported by small numbers of intact AC

  15. 31P NMR analysis of intracellular pH of Swiss Mouse 3T3 cells: effects of extracellular Na+ and K+ and mitogenic stimulation.

    Science.gov (United States)

    Civan, M M; Williams, S R; Gadian, D G; Rozengurt, E

    1986-01-01

    Swiss mouse 3T3 cells grown on microcarrier beads were superfused with electrolyte solution during continuous NMR analysis. Conventional 31P and 19F probes of intracellular pH (pHc) were found to be impracticable. Cells were therefore superfused with 1 to 4 mM 2-deoxyglucose, producing a large intracellular, pH-sensitive signal of 2-deoxyglucose phosphate (2DGP). The intracellular incorporation of 2DGP inhibited the Embden-Meyerhof pathway. However, intracellular ATP was at least in part retained and the cellular responsivity to changes in extracellular ionic composition and to the application of growth factors proved intact. Transient replacement of external Na+ with choline or K+ reversibly acidified the intracellular fluids. Quiescent cells and mitogenically stimulated cells displayed the same dependence of shifts in pHc on external Na+ concentration (CoNa). PHc also depended on intracellular Na+ concentration (CcNa). Increasing ccNa by withdrawing external K+ (thereby inhibiting the Na,K-pump) caused reversible intracellular acidification; subsequently reducing CoNa produced a larger acid shift in pHc than with external K+ present. Comparison of separate preparations indicated that pHc was higher in stimulated than in quiescent cells. Transient administration of mitogens also reversibly alkalinized quiescent cells studied continuously. This study documents the feasibility of monitoring pHc of Swiss mouse 3T3 cells using 31P NMR analysis of 2DGP. The results support the concept of a Na/H antiport operative in these cells, both in quiescence and after mitogenic stimulation. The data document by an independent technique that cytoplasmic alkalinization is an early event in mitogenesis, and that full activity of the Embden-Meyerhof pathway is not required for the expression of this event.

  16. Fibroblast-Specific Genetic Manipulation of p38 Mitogen-Activated Protein Kinase In Vivo Reveals Its Central Regulatory Role in Fibrosis.

    Science.gov (United States)

    Molkentin, Jeffery D; Bugg, Darrian; Ghearing, Natasha; Dorn, Lisa E; Kim, Peter; Sargent, Michelle A; Gunaje, Jagadambika; Otsu, Kinya; Davis, Jennifer

    2017-08-08

    In the heart, acute injury induces a fibrotic healing response that generates collagen-rich scarring that is at first protective but if inappropriately sustained can worsen heart disease. The fibrotic process is initiated by cytokines, neuroendocrine effectors, and mechanical strain that promote resident fibroblast differentiation into contractile and extracellular matrix-producing myofibroblasts. The mitogen-activated protein kinase p38α ( Mapk14 gene) is known to influence the cardiac injury response, but its direct role in orchestrating programmed fibroblast differentiation and fibrosis in vivo is unknown. A conditional Mapk14 allele was used to delete the p38α encoding gene specifically in cardiac fibroblasts or myofibroblasts with 2 different tamoxifen-inducible Cre recombinase-expressing gene-targeted mouse lines. Mice were subjected to ischemic injury or chronic neurohumoral stimulation and monitored for survival, cardiac function, and fibrotic remodeling. Antithetically, mice with fibroblast-specific transgenic overexpression of activated mitogen-activated protein kinase kinase 6, a direct inducer of p38, were generated to investigate whether this pathway can directly drive myofibroblast formation and the cardiac fibrotic response. In mice, loss of Mapk14 blocked cardiac fibroblast differentiation into myofibroblasts and ensuing fibrosis in response to ischemic injury or chronic neurohumoral stimulation. A similar inhibition of myofibroblast formation and healing was also observed in a dermal wounding model with deletion of Mapk14 . Transgenic mice with fibroblast-specific activation of mitogen-activated protein kinase kinase 6-p38 developed interstitial and perivascular fibrosis in the heart, lung, and kidney as a result of enhanced myofibroblast numbers. Mechanistic experiments show that p38 transduces cytokine and mechanical signals into myofibroblast differentiation through the transcription factor serum response factor and the signaling effector

  17. Genome-wide genetic analyses highlight mitogen-activated protein kinase (MAPK) signaling in the pathogenesis of endometriosis.

    Science.gov (United States)

    Uimari, Outi; Rahmioglu, Nilufer; Nyholt, Dale R; Vincent, Katy; Missmer, Stacey A; Becker, Christian; Morris, Andrew P; Montgomery, Grant W; Zondervan, Krina T

    2017-04-01

    Do genome-wide association study (GWAS) data for endometriosis provide insight into novel biological pathways associated with its pathogenesis? GWAS analysis uncovered multiple pathways that are statistically enriched for genetic association signals, analysis of Stage A disease highlighted a novel variant in MAP3K4, while top pathways significantly associated with all endometriosis and Stage A disease included several mitogen-activated protein kinase (MAPK)-related pathways. Endometriosis is a complex disease with an estimated heritability of 50%. To date, GWAS revealed 10 genomic regions associated with endometriosis, explaining endometriosis cases and 7060 controls of European ancestry with genotype data imputed up to 1000 Genomes Phase three reference panel. GWAS was performed for all endometriosis cases and for Stage A (revised American Fertility Society (rAFS) I/II, n = 1686) and B (rAFS III/IV, n = 1364) cases separately. The identified significant pathways were compared with pathways previously investigated in the literature through candidate association studies. The most comprehensive biological pathway databases, MSigDB (including BioCarta, KEGG, PID, SA, SIG, ST and GO) and PANTHER were utilized to test for enrichment of genetic variants associated with endometriosis. Statistical enrichment analysis was performed using the MAGENTA (Meta-Analysis Gene-set Enrichment of variaNT Associations) software. The first genome-wide association analysis for Stage A endometriosis revealed a novel locus, rs144240142 (P = 6.45 × 10-8, OR = 1.71, 95% CI = 1.23-2.37), an intronic single-nucleotide polymorphism (SNP) within MAP3K4. This SNP was not associated with Stage B disease (P = 0.086). MAP3K4 was also shown to be differentially expressed in eutopic endometrium between Stage A endometriosis cases and controls (P = 3.8 × 10-4), but not with Stage B disease (P = 0.26). A total of 14 pathways enriched with genetic endometriosis associations were identified (false

  18. p38 mitogen-activated protein kinase is involved in arginase-II-mediated eNOS-uncoupling in obesity.

    Science.gov (United States)

    Yu, Yi; Rajapakse, Angana G; Montani, Jean-Pierre; Yang, Zhihong; Ming, Xiu-Fen

    2014-07-18

    Endothelial nitric oxide synthase (eNOS)-uncoupling links obesity-associated insulin resistance and type-II diabetes to the increased incidence of cardiovascular disease. Studies have indicated that increased arginase is involved in eNOS-uncoupling through competing with the substrate L-arginine. Given that arginase-II (Arg-II) exerts some of its biological functions through crosstalk with signal transduction pathways, and that p38 mitogen-activated protein kinase (p38mapk) is involved in eNOS-uncoupling, we investigated here whether p38mapk is involved in Arg-II-mediated eNOS-uncoupling in a high fat diet (HFD)-induced obesity mouse model. Obesity was induced in wild type (WT) and Arg-II-deficient (Arg-II(-/-)) mice on C57BL/6 J background by high-fat diet (HFD, 55% fat) for 14 weeks starting from age of 7 weeks. The entire aortas were isolated and subjected to 1) immunoblotting analysis of the protein level of eNOS, Arg-II and p38mapk activation; 2) arginase activity assay; 3) endothelium-dependent and independent vasomotor responses; 4) en face staining of superoxide anion and NO production with Dihydroethidium and 4,5-Diaminofluorescein Diacetate, respectively, to assess eNOS-uncoupling. To evaluate the role of p38mapk, isolated aortas were treated with p38mapk inhibitor SB203580 (10 μmol/L, 1 h) prior to the analysis. In addition, the role of p38mapk in Arg-II-induced eNOS-uncoupling was investigated in cultured human endothelial cells overexpressing Arg-II in the absence or presence of shRNA against p38mapk. HFD enhanced Arg-II expression/activity and p38mapk activity, which was associated with eNOS-uncoupling as revealed by decreased NO and enhanced L-NAME-inhibitable superoxide in aortas of WT obese mice. In accordance, WT obese mice revealed decreased endothelium-dependent relaxations to acetylcholine despite of higher eNOS protein level, whereas Arg-II(-/-) obese mice were protected from HFD-induced eNOS-uncoupling and endothelial dysfunction, which

  19. The influence of in vitro and in vivo exposure to antibiotics on mitogen-induced proliferation of lymphoid cells in rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Lundén, T; Bylund, G

    2000-07-01

    The influence of five different antimicrobial drugs on mitogen-induced lymphoid cell proliferation in vitro and after oral administration of the drugs was studied in rainbow trout (Oncorhynchus mykiss). The drugs tested were: oxolinic acid, oxytetracycline, florfenicol and trimethoprim in combination with sulfadiazine in ratio 1:5. In the in vitro tests, trimethoprim:sulfadiazine increased the 3H-thymidine incorporation into the DNA of phytohaemagglutinin and lipopolysaccharide-stimulated lymphoid cells while all the other drugs tested interfered negatively with the incorporation in a dose dependent manner. In the experiment with oral drug administration, the fish were fed 10 days with a therapeutic dose of the drugs. After the drug treatment, lymphoid cells were isolated from the head kidney of the fish and tested for proliferating capacity. All drugs except trimethoprim+sulfadiazine, suppressed the mitogenic response of the head kidney cells. The suppression of the response was more severe in phytohaemagglutinin-stimulated than in lipopolysaccharide-stimulated cells indicating that the T-cells were more vulnerable to the toxic effects of the drugs than B-cells.

  20. Modulation of Cyclins, p53 and Mitogen-Activated Protein Kinases Signaling in Breast Cancer Cell Lines by 4-(3,4,5-Trimethoxyphenoxybenzoic Acid

    Directory of Open Access Journals (Sweden)

    Kuan-Han Lee

    2014-01-01

    Full Text Available Despite the advances in cancer therapy and early detection, breast cancer remains a leading cause of cancer-related deaths among females worldwide. The aim of the current study was to investigate the antitumor activity of a novel compound, 4-(3,4,5-trimethoxyphenoxybenzoic acid (TMPBA and its mechanism of action, in breast cancer. Results indicated the relatively high sensitivity of human breast cancer cell-7 and MDA-468 cells towards TMPBA with IC50 values of 5.9 and 7.9 µM, respectively compared to hepatocarcinoma cell line Huh-7, hepatocarcinoma cell line HepG2, and cervical cancer cell line Hela cells. Mechanistically, TMPBA induced apoptotic cell death in MCF-7 cells as indicated by 4',6-diamidino-2-phenylindole (DAPI nuclear staining, cell cycle analysis and the activation of caspase-3. Western blot analysis revealed the ability of TMPBA to target pathways mediated by mitogen-activated protein (MAP kinases, 5' adenosine monophosphate-activated protein kinase (AMPK, and p53, of which the concerted action underlined its antitumor efficacy. In addition, TMPBA induced alteration of cyclin proteins’ expression and consequently modulated the cell cycle. Taken together, the current study underscores evidence that TMPBA induces apoptosis in breast cancer cells via the modulation of cyclins and p53 expression as well as the modulation of AMPK and mitogen-activated protein kinases (MAPK signaling. These findings support TMPBA’s clinical promise as a potential candidate for breast cancer therapy.

  1. Epidermal Growth Factor Receptor Transactivation Is Required for Mitogen-Activated Protein Kinase Activation by Muscarinic Acetylcholine Receptors in HaCaT Keratinocytes

    Directory of Open Access Journals (Sweden)

    Wymke Ockenga

    2014-11-01

    Full Text Available Non-neuronal acetylcholine plays a substantial role in the human skin by influencing adhesion, migration, proliferation and differentiation of keratinocytes. These processes are regulated by the Mitogen-Activated Protein (MAP kinase cascade. Here we show that in HaCaT keratinocytes all five muscarinic receptor subtypes are expressed, but M1 and M3 are the subtypes involved in mitogenic signaling. Stimulation with the cholinergic agonist carbachol leads to activation of the MAP kinase extracellular signal regulated kinase, together with the protein kinase Akt. The activation is fully dependent on the transactivation of the epidermal growth factor receptor (EGFR, which even appears to be the sole pathway for the muscarinic receptors to facilitate MAP kinase activation in HaCaT cells. The transactivation pathway involves a triple-membrane-passing process, based on activation of matrix metalloproteases, and extracellular ligand release; whereas phosphatidylinositol 3-kinase, Src family kinases or protein kinase C do not appear to be involved in MAP kinase activation. Furthermore, phosphorylation, ubiquitination and endocytosis of the EGF receptor after cholinergic transactivation are different from that induced by a direct stimulation with EGF, suggesting that ligands other than EGF itself mediate the cholinergic transactivation.

  2. Effect of nerve growth factor on the expression of cell cycle regulatory proteins in PC12 cells: dissection of the neurotrophic response from the anti-mitogenic response.

    Science.gov (United States)

    van Grunsven, L A; Billon, N; Savatier, P; Thomas, A; Urdiales, J L; Rudkin, B B

    1996-03-21

    PC12 cells treated with nerve growth factor (NGF) undergo a G1 block and differentiate. Expression of selected cell cycle regulatory proteins was studied under culture conditions which permit observation of a differentiation response independently from a mitogenic or anti-mitogenic response. The expression of all cell cycle regulatory proteins studied is modulated by NGF addition to exponentially-growing cultures in the presence of serum. While levels of most of these proteins decrease, accumulation of cyclin D1 and the cyclin-dependent kinase inhibitor p21 Cip1/WAF1 is observed. Cyclin D1 associated kinase activity is inhibited, correlating with an increase in p21 protein. PC12 cells, synchronized by serum starvation, undergo morphological and functional differentiation in the presence of NGF. Neither cyclin D1 nor p21 are present in such cultures, nor is their expression upregulated by NGF, indicating that they are not required for this process. Removal of serum from differentiated PC12 cells results in loss of these proteins, but has no effect on differentiation or the nonproliferative state in presence of NGF. Together, the results indicate that cyclin D1 and p21 are not necessary for differentiation per se, nor are they required for maintenance of the differentiated state in the absence of serum.

  3. Recruitment of focal adhesion kinase and paxillin to β1 integrin promotes cancer cell migration via mitogen activated protein kinase activation

    Directory of Open Access Journals (Sweden)

    Ohannessian Arthur

    2004-05-01

    Full Text Available Abstract Background Integrin-extracellular matrix interactions activate signaling cascades such as mitogen activated protein kinases (MAPK. Integrin binding to extracellular matrix increases tyrosine phosphorylation of focal adhesion kinase (FAK. Inhibition of FAK activity by expression of its carboxyl terminus decreases cell motility, and cells from FAK deficient mice also show reduced migration. Paxillin is a focal adhesion protein which is also phosphorylated on tyrosine. FAK recruitment of paxillin to the cell membrane correlates with Shc phosphorylation and activation of MAPK. Decreased FAK expression inhibits papilloma formation in a mouse skin carcinogenesis model. We previously demonstrated that MAPK activation was required for growth factor induced in vitro migration and invasion by human squamous cell carcinoma (SCC lines. Methods Adapter protein recruitment to integrin subunits was examined by co-immunoprecipitation in SCC cells attached to type IV collagen or plastic. Stable clones overexpressing FAK or paxillin were created using the lipofection technique. Modified Boyden chambers were used for invasion assays. Results In the present study, we showed that FAK and paxillin but not Shc are recruited to the β1 integrin cytoplasmic domain following attachment of SCC cells to type IV collagen. Overexpression of either FAK or paxillin stimulated cancer cell migration on type IV collagen and invasion through reconstituted basement membrane which was dependent on MAPK activity. Conclusions We concluded that recruitment of focal adhesion kinase and paxillin to β1 integrin promoted cancer cell migration via the mitogen activated protein kinase pathway.

  4. Purification and characterization of erythrogenic toxins of Streptococcus pyogenes. VI. Mitogenic activity of isoelectrically focused erythrogenic toxin preparations and culture supernatants of group A streptococci.

    Science.gov (United States)

    Knöll, H; Gerlach, D; Ozegowski, J H; Hribalová, V; Köhler, W

    1983-11-01

    Isoelectric focusing (IF) was used to separate erythrogenic toxins (ET) type A, B and C from concentrated culture filtrates of Streptococcus pyogenes strains. The ET's were identified by their mitogenic activity on human lymphocytes in the lymphocyte transformation test: purified ET type A appeared at pH 5.3, ET type C at pH 6.8 and ET type B at pH 7.5 to 8.5; the ET type B was only biologically active when PAGE IF was used. IF on Sephadex G 100 failed to yield active B toxin. The application of as little as 0.1 micrograms ET type A to an isoelectric focusing gel was still sufficient to detect a mitogenic peak in the eluates. ET type A was identified in nine out of 10 culture filtrates, ET type C in 4 out of 10. Detection of ET type B (identical with streptococcal proteinase proenzyme) in culture filtrates after IF proved to be difficult. Here the pH of cultivation media and the autocatalytic conversion of streptococcal proteinase proenzyme to activated proteinase have to be considered.

  5. Mitogenic effects of a mesothelial cell growth factor: evidence for a potential autocrine regulation of normal and malignant mesothelial cell proliferation.

    Science.gov (United States)

    Donna, A.; Betta, P. G.; Ribotta, M.; Maran, E.; Mazzucco, G.; Mollo, F.; Bellingeri, D.; Libener, R.

    1992-01-01

    We have investigated the growth-factor-like activity of a approximately 200-kDa, IP 8.3, cytoplasmic glycoprotein, the expression of which appears to be restricted to normal and malignant human mesothelium. This substance stimulated the growth of human mesothelioma cell cultures at greater rates than did foetal calf serum, but it failed to induce proliferation of lung carcinoma cell cultures. In addition, we have tried to trace the biosynthetic pathway of this mitogenic factor in normal human mesothelial cells by means of immuno-electron microscopy with a polyclonal antibody directed against this molecule. Positive immunogold labelling was found in the lumina of the cisternae of the endoplasmic reticulum, to a lesser extent on the outer surface of the plasma membrane, and also in structures corresponding to the coated pits. These ultrastructural findings are consistent with the hypothesis of the glycosylation of the newly synthesized protein in the endoplasmic reticulum and the subsequent uptake of the secreted molecule, which accumulates in the coated pits before internalization. The results suggest that this mitogenic glycoprotein could play a role in an autocrine growth control mechanism influencing mesothelial cell proliferation. Images Fig. 1 Fig. 2 Fig. 3 PMID:1571279

  6. Gender differences and inflammation: an in vitro model of blood cells stimulation in prepubescent children

    Directory of Open Access Journals (Sweden)

    Corazza Francis

    2010-06-01

    Full Text Available Abstract Background Gender influences clinical presentations and markers in inflammatory diseases. In many chronic conditions, frequency of complications is greater in females, suggesting that continuous inflammatory reaction may induce greater damage in targeted organs and functions. Methods To investigate gender dimorphism at a cellular level, we evaluated the production of cytokines implicated in inflammatory processes (IL -1, IL- 6, PGE-2 and TNF alpha, in healthy prepubescent children of both sex and Turner's syndrome (TS patients (genotype XO. We used stimulation by LPS (0.2 and 1 ng/ml and Pokeweed Mitogen (PWM on overnight cultures from whole blood samples, collected in 57 subjects: 22 girls/26 boys (5-96 months, and 9 TS patients (6-15 years. The primary outcome was to evaluate if gender influences the production of cytokines, with potential relation to X chromosome monosomy. Secondary endpoints were to relate different cytokines level productions and conditions. Results We confirm the male over female increased cytokine productions already observed in adults. This is contrasting with numerous observations obtained in vivo about increased production of inflammatory markers in females (CRP, ESR and neutrophil counts, as we recently reported in children. Relative variations of the dimorphism according to stimulus, its concentration and cytokine type are discussed, presenting IL6 with a modulating function that could be more potent in males. TS subjects follow mostly the male pattern of reactivity, sustaining the role of some gene expression differing with X chromosome monosomy and disomy. Conclusions Persistence of the latter dimorphism throughout life casts doubts on its direct relationship with individual hormonal status, as already documented by others in vitro, and supports the need for alternative hypothesis, such as the influence of X chromosome gene products escaping X inactivation in females and absent in subjects with X monosomy

  7. Towards establishing a rhinoceros-specific interferon-gamma (IFN-γ) assay for diagnosis of tuberculosis.

    Science.gov (United States)

    Morar, D; Schreuder, J; Mény, M; van Kooten, P J S; Tijhaar, E; Michel, A L; Rutten, V P M G

    2013-11-01

    Mycobacterium bovis is the causal agent of bovine tuberculosis (BTB), with a diverse host range, extending from livestock to domestic and captive wild animals as well as free-ranging wildlife species. In South Africa, BTB is endemic in the Kruger National Park (KNP) and the Hluluwe iMfolozi National Park (HiP), where the high prevalence of M. bovis infections in buffalo herds has led to infection of a number of wildlife species. This has raised concerns about the spillover into the rhinoceros population, a species known to be susceptible to both M. bovis and Mycobacterium tuberculosis, jeopardizing breeding and relocation projects that serve to conserve and protect this species. In view of the advantages of the interferon-gamma (IFN-γ) assay in the diagnosis of BTB in a variety of species worldwide, such an assay has been developed for rhinoceroses by Morar and co-workers in 2007. In this study, this assay was optimized using recombinant eukaryotic rhinoceros IFN-γ and the lower detection limit was calculated to be 0.5 ng/ml. Subsequently, assessing the detection of native rhinoceros IFN-γ protein in whole-blood samples revealed stimulation with each of the mitogens: pokeweed (PWM), phytohaemagglutinin (PHA) & phorbol 12-myristate 13-acetate and calcium ionophore (PMA/CaI), though most prominently with the latter two. In addition, samples collected from 52 clinically healthy rhinoceroses, of presumed negative BTB status, from two different areas in South Africa were used to determine the cut-off value for a negative test result. This was calculated to be 0.10 (OD490 nm ) and as determined in this study is a preliminary recommendation based on IFN-γ responses observed in samples from BTB-free rhinoceroses only. © 2013 Blackwell Verlag GmbH.

  8. Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

    International Nuclear Information System (INIS)

    Gao, Gongming; Shen, Nan; Jiang, Xuefeng; Sun, Huiqing; Xu, Nanwei; Zhou, Dong; Nong, Luming; Ren, Kewei

    2016-01-01

    The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferation (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.

  9. Periodic mechanical stress activates EGFR-dependent Rac1 mitogenic signals in rat nucleus pulpous cells via ERK1/2

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Gongming [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Shen, Nan [Department of Clinical Pharmacy, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China); Jiang, Xuefeng; Sun, Huiqing [Department of Orthopedics, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China); Xu, Nanwei; Zhou, Dong [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Nong, Luming, E-mail: lumingnong@hotmail.com [Department of Orthopedics, The Affiliated Changzhou No. 2 Hospital of Nanjing Medical University, Changzhou 213003 (China); Ren, Kewei, E-mail: keweiren@hotmail.com [Department of Orthopedics, The Affiliated Jiangyin Hospital of Southeast University Medical School, Jiangyin 214400 (China)

    2016-01-15

    The mitogenic effects of periodic mechanical stress on nucleus pulpous cells have been studied extensively but the mechanisms whereby nucleus pulpous cells sense and respond to mechanical stimulation remain a matter of debate. We explored this question by performing cell culture experiments in our self-developed periodic stress field and perfusion culture system. Under periodic mechanical stress, rat nucleus pulpous cell proliferation was significantly increased (p < 0.05 for each) and was associated with increases in the phosphorylation and activation of EGFR, Rac1, and ERK1/2 (p < 0.05 for each). Pretreatment with the ERK1/2 selective inhibitor PD98059 reduced periodic mechanical stress-induced nucleus pulpous cell proliferation (p < 0.05 for each), while the activation levels of EGFR and Rac1 were not inhibited. Proliferation and phosphorylation of ERK1/2 were inhibited after pretreatment with the Rac1 inhibitor NSC23766 in nucleus pulpous cells in response to periodic mechanical stress (p < 0.05 for each), while the phosphorylation site of EGFR was not affected. Inhibition of EGFR activity with AG1478 abrogated nucleus pulpous cell proliferation (p < 0.05 for each) and attenuated Rac1 and ERK1/2 activation in nucleus pulpous cells subjected to periodic mechanical stress (p < 0.05 for each). These findings suggest that periodic mechanical stress promotes nucleus pulpous cell proliferation in part through the EGFR-Rac1-ERK1/2 signaling pathway, which links these three important signaling molecules into a mitogenic cascade. - Highlights: • The mechanism involved in nucleus pulpous cells to respond to mechanical stimuli. • Periodic mechanical stress can stimulate the phosphorylation of EGFR. • EGFR activates Rac1 and leads to rat nucleus pulpous cell proliferation. • EGFR and Rac1 activate ERK1/2 mitogenic signals in nucleus pulpous cells. • EGFR-Rac1-ERK1/2 is constitutes at least one critical signal transduction pathway.

  10. Cloning of a mitogen-inducible gene encoding a kappa B DNA-binding protein with homology to the rel oncogene and to cell-cycle motifs.

    Science.gov (United States)

    Bours, V; Villalobos, J; Burd, P R; Kelly, K; Siebenlist, U

    1990-11-01

    We have cloned and characterized a mitogen-inducible gene isolated from human T cells that predicts a protein of 968 amino acids. The amino-terminal domain has regions homologous to the oncogene rel and to the developmentally important gene dorsal of Drosophila. The carboxy-terminal domain contains repeat structures found in a variety of proteins that are involved in cell-cycle control of yeast and in tissue differentiation in Drosophila and Ceanorhabditis elegans, as well as in the putative human oncogene bcl-3 and in the ankyrin protein. A truncated form of the product of this gene translated in vitro is a DNA-binding protein which interacts specifically with the kappa B binding site found in many inducible genes, including the enhancer in human immunodeficiency virus. This gene is yet another in a growing list of important regulatory molecules whose expression is transcriptionally induced upon cellular activation.

  11. The Na+/H+ exchanger, NHE1, differentially regulates mitogen-activated protein kinase subfamilies after osmotic shrinkage in Ehrlich Lettre Ascites cells

    DEFF Research Database (Denmark)

    Petersen, Stine Helene Falsig; Rasmussen, Maria; Darborg, Barbara Vasek

    2007-01-01

    Osmotic stress modulates mitogen activated protein kinase (MAPK) activities, leading to altered gene transcription and cell death/survival balance, however, the mechanisms involved are incompletely elucidated. Here, we show, using a combination of biochemical and molecular biology approaches......, that three MAPKs exhibit unique interrelationships with the Na(+)/H(+) exchanger, NHE1, after osmotic cell shrinkage: Extracellular Signal Regulated Kinase (ERK1/2) is inhibited in an NHE1-dependent, pH(i)-independent manner, c-Jun N-terminal kinase (JNK1/2) is stimulated, in part through NHE1-mediated...... intracellular alkalinization, and p38 MAPK is activated in an NHE1-independent manner, and contributes to NHE1 activation and ERK inhibition. Shrinkage-induced ERK1/2 inhibition was attenuated in Ehrlich Lettre Ascites cells by NHE1 inhibitors (EIPA, cariporide) or removal of extracellular Na(+), and mimicked...

  12. Glucose, other secretagogues, and nerve growth factor stimulate mitogen-activated protein kinase in the insulin-secreting beta-cell line, INS-1

    DEFF Research Database (Denmark)

    Frödin, M; Sekine, N; Roche, E

    1995-01-01

    The signaling pathways whereby glucose and hormonal secretagogues regulate insulin-secretory function, gene transcription, and proliferation of pancreatic beta-cells are not well defined. We show that in the glucose-responsive beta-cell line INS-1, major secretagogue-stimulated signaling pathways...... converge to activate 44-kDa mitogen-activated protein (MAP) kinase. Thus, glucose-induced insulin secretion was found to be associated with a small stimulatory effect on 44-kDa MAP kinase, which was synergistically enhanced by increased levels of intracellular cAMP and by the hormonal secretagogues......-1. Phorbol ester, an activator of protein kinase C, stimulated 44-kDa MAP kinase by both Ca(2+)-dependent and -independent pathways. Nerve growth factor, independently of changes in cytosolic Ca2+, efficiently stimulated 44-kDa MAP kinase without causing insulin release, indicating that activation...

  13. IL-20 gene expression is induced by IL-1beta through mitogen-activated protein kinase and NF-kappaB-dependent mechanisms

    DEFF Research Database (Denmark)

    Otkjaer, Kristian; Kragballe, Knud; Johansen, Claus

    2007-01-01

    IL-20 is a novel member of the IL-10 cytokine family with pleiotropic effects. Current knowledge of what triggers and regulates IL-20 gene expression is sparse. The aim of this study was to investigate the regulation of IL-20 expression in cultured normal human keratinocytes. The expression of IL...... the p38 MAPK, MSK1, and NF-kappaB may be important new molecular targets for the modulation of IL-20 expression in these diseases. Udgivelsesdato: 2007-Jun...... activation of the downstream kinase mitogen- and stress-activated kinase 1 (MSK1), indicating transactivation of NF-kappaB driven IL-20 messenger RNA transcription as an important mechanism of action. IL-20 is assumed to be a key cytokine in the pathogenesis of psoriasis and possibly cancer, and therefore...

  14. T-cell subset alterations and lymphocyte responsiveness to mitogens and antigen during severe primary infection with HIV: a case series of seven consecutive HIV seroconverters

    DEFF Research Database (Denmark)

    Pedersen, C; Dickmeiss, E; Gaub, J

    1990-01-01

    Seven consecutive patients who presented with a severe acute mononucleosis-like illness associated with HIV seroconversion were evaluated by T-cell subset enumerations and measurements of lymphocyte transformation responses to mitogens and antigen during both their primary illness and a 1-year...... follow-up period. We observed a characteristic pattern of response to primary HIV infection; initial lymphopenia was followed by CD8 lymphocytosis and inversion of the CD4:CD8 ratio. During follow-up, the CD8 count gradually returned to normal, whereas the CD4:CD8 ratio remained inverted because....... We conclude that severe primary HIV infection may be followed by sustained lymphocyte hyporesponsiveness, a sustained low percentage of CD4 lymphocytes and sustained inversion of the CD4:CD8 ratio....

  15. Subtype activation and interaction of protein kinase C and mitogen-activated protein kinase controlling receptor expression in cerebral arteries and microvessels after subarachnoid hemorrhage

    DEFF Research Database (Denmark)

    Ansar, S.; Edvinsson, L.

    2008-01-01

    BACKGROUND AND PURPOSE: The pathogenesis of cerebral ischemia associated with subarachnoid hemorrhage (SAH) still remains elusive. The aim of this study was to examine the involvement of mitogen-activated protein kinase (MAPK) and protein kinase C (PKC) subtypes in the pathophysiology of cerebral...... ischemia after SAH in cerebral arteries and microvessels and to examine temporal activation of the kinases. We hypothesize that treatment with a MAPK or PKC inhibitor will prevent the SAH-induced kinase activation in brain vessels. METHODS: SAH was induced by injecting 250 microL blood...... into the prechiasmatic cistern in the rat. The activation of different MAPK and PKC isotypes in large circle of Willis cerebral arteries and intracerebral microvessels was examined at 0, 1, 3, 6, 12, 24, and 48 hours after SAH and after intrathecal treatment with PKC or MAPK inhibitor by use of Western blot. RESULTS...

  16. Beauvericin-induced cell apoptosis through the mitogen-activated protein kinase pathway in human nonsmall cell lung cancer A549 cells.

    Science.gov (United States)

    Lu, Chien-Lin; Lin, Hen-I; Chen, Bing-Fang; Jow, Guey-Mei

    2016-01-01

    Beauvericin (BEA) is a cyclic hexadepsipeptide that derives from Codyceps cicadae. Our previous study results indicated that the cytotoxic effects of BEA on human A549 lung cancer cells BEA occur through an apoptotic pathway, which involves the up-regulation of cytochrome c release from mitochondria, upregulation of caspase 3 activity, and cellular and morphological changes. In this study, we identified that the mitogen-activated protein kinase (MAPK) inhibitor U0126 inhibits the cytotoxic effects of BEA on A549 cells. After exposing human A549 cells to 10 μM BEA, we observed a significant and dose-dependent increase in the percentage of hypoploid (sub-G1) phase cells in the A549 population. Following the pretreatment of the A549 cells with 25 μM U0126, the distribution of A549 cells in the sub-G1 phase decreased significantly. The BEA treatment resulted in a significant increase apoptosis in A549 cells by in situ terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Moreover, the MEK1/2 (mitogen-activated protein kinase kinase)-ERK42/44 (extracellular signal-regulated kinases)-90RSK (ribosomal s6 kinase) signaling pathway was activated in BEA-induced apoptotic A549 cells. Furthermore, treatment with MEK1/2 inhibitor U0126 was capable to attenuate the BEA induced typical apoptotic morphological change, apoptotic cells, and MEK1/2-ERK42/44-90RSK signaling pathway. These results suggested that MEK1/2-ERK42/44-90RSK signaling pathway may play a important role in BEA-induced apoptosis in human NSCLC A549 cancer cells.

  17. Genome-wide identification of mitogen-activated protein kinase gene family in Gossypium raimondii and the function of their corresponding orthologs in tetraploid cultivated cotton.

    Science.gov (United States)

    Zhang, Xueying; Wang, Liman; Xu, Xiaoyang; Cai, Caiping; Guo, Wangzhen

    2014-12-10

    Mitogen-activated protein kinase (MAPK) cascades play a crucial role in plant growth and development as well as biotic and abiotic stress responses. Knowledge about the MAPK gene family in cotton is limited, and systematic investigation of MAPK family proteins has not been reported. By performing a bioinformatics homology search, we identified 28 putative MAPK genes in the Gossypium raimondii genome. These MAPK members were anchored onto 11 chromosomes in G. raimondii, with uneven distribution. Phylogenetic analysis showed that the MAPK candidates could be classified into the four known A, B, C and D groups, with more MAPKs containing the TEY phosphorylation site (18 members) than the TDY motif (10 members). Furthermore, 21 cDNA sequences of MAPKs with complete open reading frames (ORFs) were identified in G. hirsutum via PCR-based approaches, including 13 novel MAPKs and eight with homologs reported previously in tetraploid cotton. The expression patterns of 23 MAPK genes reveal their important roles in diverse functions in cotton, in both various developmental stages of vegetative and reproductive growth and in the stress response. Using a reverse genetics approach based on tobacco rattle virus-induced gene silencing (TRV-VIGS), we further verified that MPK9, MPK13 and MPK25 confer resistance to defoliating isolates of Verticillium dahliae in cotton. Silencing of MPK9, MPK13 and MPK25 can significantly enhance cotton susceptibility to this pathogen. This study presents a comprehensive identification of 28 mitogen-activated protein kinase genes in G. raimondii. Their phylogenetic relationships, transcript expression patterns and responses to various stressors were verified. This study provides the first systematic analysis of MAPKs in cotton, improving our understanding of defense responses in general and laying the foundation for future crop improvement using MAPKs.

  18. The potent, indirect adenosine monophosphate-activated protein kinase activator R419 attenuates mitogen-activated protein kinase signaling, inhibits nociceptor excitability, and reduces pain hypersensitivity in mice

    Directory of Open Access Journals (Sweden)

    Galo L. Mejia

    2016-07-01

    Full Text Available Abstract. There is a great need for new therapeutics for the treatment of pain. A possible avenue to development of such therapeutics is to interfere with signaling pathways engaged in peripheral nociceptors that cause these neurons to become hyperexcitable. There is strong evidence that mitogen-activated protein kinases and phosphoinositide 3-kinase (PI3K/mechanistic target of rapamycin signaling pathways are key modulators of nociceptor excitability in vitro and in vivo. Activation of adenosine monophosphate-activated protein kinase (AMPK can inhibit signaling in both of these pathways, and AMPK activators have been shown to inhibit nociceptor excitability and pain hypersensitivity in rodents. R419 is one of, if not the most potent AMPK activator described to date. We tested whether R419 activates AMPK in dorsal root ganglion (DRG neurons and if this leads to decreased pain hypersensitivity in mice. We find that R419 activates AMPK in DRG neurons resulting in decreased mitogen-activated protein kinase signaling, decreased nascent protein synthesis, and enhanced P body formation. R419 attenuates nerve growth factor (NGF-induced changes in excitability in DRG neurons and blocks NGF-induced mechanical pain amplification in vivo. Moreover, locally applied R419 attenuates pain hypersensitivity in a model of postsurgical pain and blocks the development of hyperalgesic priming in response to both NGF and incision. We conclude that R419 is a promising lead candidate compound for the development of potent and specific AMPK activation to inhibit pain hypersensitivity as a result of injury.

  19. Mitogen-activated protein kinase 1 from disk abalone (Haliotis discus discus): Roles in early development and immunity-related transcriptional responses.

    Science.gov (United States)

    Perera, N C N; Godahewa, G I; Lee, Jehee

    2016-12-01

    Mitogen-activated protein kinase (MAPK) is involved in the regulation of cellular events by mediating signal transduction pathways. MAPK1 is a member of the extracellular-signal regulated kinases (ERKs), playing roles in cell proliferation, differentiation, and development. This is mainly in response to growth factors, mitogens, and many environmental stresses. In the current study, we have characterized the structural features of a homolog of MAPK1 from disk abalone (AbMAPK1). Further, we have unraveled its expressional kinetics against different experimental pathogenic infections or related chemical stimulants. AbMAPK1 harbors a 5' untranslated region (UTR) of 23 bps, a coding sequence of 1104 bps, and a 3' UTR of 448 bp. The putative peptide comprises a predicted molecular mass of 42.2 kDa, with a theoretical pI of 6.28. Based on the in silico analysis, AbMAPK1 possesses two N-glycosylation sites, one S_TK catalytic domain, and a conserved His-Arg-Asp domain (HRD). In addition, a conservative glycine rich ATP-phosphate-binding loop and a threonine-x-tyrosine motif (TEY) important for the autophosphorylation were also identified in the protein. Homology assessment of AbMAPK1 showed several conserved regions, and ark clam (Aplysia californica) showed the highest sequence identity (87.9%). The phylogenetic analysis supported close evolutionary kinship with molluscan orthologs. Constitutive expression of AbMAPK1 was observed in six different tissues of disk abalone, with the highest expression in the digestive tract, followed by the gills and hemocytes. Highest AbMAPK1 mRNA expression level was detected at the trochophore developmental stage, suggesting its role in abalone cell differentiation and proliferation. Significant modulation of AbMAPK1 expression under pathogenic stress suggested its putative involvement in the immune defense mechanism. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Participation of Mitogen-activated Protein Kinase in Luteinizing Hormone-induced Differential Regulation of Steroidogenesis and Steroidogenic Gene Expression in Mural and Cumulus Granulosa Cells of Mouse Preovulatory Follicles

    DEFF Research Database (Denmark)

    Su, You-Qiang; Nyegaard, Mette; Overgaard, Michael Toft

    2006-01-01

    was to investigate whether these processes that commonly occur in mural granulosa cells (MGCs) also occur in cumulus cells, and whether they are mediated by the mitogen-activated protein kinase (MAPK), specifically MAPK3/1 (also commonly known as extracellular signal-regulated kinase 1&2, ERK1/2). The standard...

  1. NAD+ Levels Control Ca2+ Store Replenishment and Mitogen-induced Increase of Cytosolic Ca2+ by Cyclic ADP-ribose-dependent TRPM2 Channel Gating in Human T Lymphocytes*

    Science.gov (United States)

    Magnone, Mirko; Bauer, Inga; Poggi, Alessandro; Mannino, Elena; Sturla, Laura; Brini, Marisa; Zocchi, Elena; De Flora, Antonio; Nencioni, Alessio; Bruzzone, Santina

    2012-01-01

    Intracellular NAD+ levels ([NAD+]i) are important in regulating human T lymphocyte survival, cytokine secretion, and the capacity to respond to antigenic stimuli. NAD+-derived Ca2+-mobilizing second messengers, produced by CD38, play a pivotal role in T cell activation. Here we demonstrate that [NAD+]i modifications in T lymphocytes affect intracellular Ca2+ homeostasis both in terms of mitogen-induced [Ca2+]i increase and of endoplasmic reticulum Ca2+ store replenishment. Lowering [NAD+]i by FK866-mediated nicotinamide phosphoribosyltransferase inhibition decreased the mitogen-induced [Ca2+]i rise in Jurkat cells and in activated T lymphocytes. Accordingly, the Ca2+ content of thapsigargin-sensitive Ca2+ stores was greatly reduced in these cells in the presence of FK866. When NAD+ levels were increased by supplementing peripheral blood lymphocytes with the NAD+ precursors nicotinamide, nicotinic acid, or nicotinamide mononucleotide, the Ca2+ content of thapsigargin-sensitive Ca2+ stores as well as cell responsiveness to mitogens in terms of [Ca2+]i elevation were up-regulated. The use of specific siRNA showed that the changes of Ca2+ homeostasis induced by NAD+ precursors are mediated by CD38 and the consequent ADPR-mediated TRPM2 gating. Finally, the presence of NAD+ precursors up-regulated important T cell functions, such as proliferation and IL-2 release in response to mitogens. PMID:22547068

  2. NAD+ levels control Ca2+ store replenishment and mitogen-induced increase of cytosolic Ca2+ by Cyclic ADP-ribose-dependent TRPM2 channel gating in human T lymphocytes.

    Science.gov (United States)

    Magnone, Mirko; Bauer, Inga; Poggi, Alessandro; Mannino, Elena; Sturla, Laura; Brini, Marisa; Zocchi, Elena; De Flora, Antonio; Nencioni, Alessio; Bruzzone, Santina

    2012-06-15

    Intracellular NAD(+) levels ([NAD(+)](i)) are important in regulating human T lymphocyte survival, cytokine secretion, and the capacity to respond to antigenic stimuli. NAD(+)-derived Ca(2+)-mobilizing second messengers, produced by CD38, play a pivotal role in T cell activation. Here we demonstrate that [NAD(+)](i) modifications in T lymphocytes affect intracellular Ca(2+) homeostasis both in terms of mitogen-induced [Ca(2+)](i) increase and of endoplasmic reticulum Ca(2+) store replenishment. Lowering [NAD(+)](i) by FK866-mediated nicotinamide phosphoribosyltransferase inhibition decreased the mitogen-induced [Ca(2+)](i) rise in Jurkat cells and in activated T lymphocytes. Accordingly, the Ca(2+) content of thapsigargin-sensitive Ca(2+) stores was greatly reduced in these cells in the presence of FK866. When NAD(+) levels were increased by supplementing peripheral blood lymphocytes with the NAD(+) precursors nicotinamide, nicotinic acid, or nicotinamide mononucleotide, the Ca(2+) content of thapsigargin-sensitive Ca(2+) stores as well as cell responsiveness to mitogens in terms of [Ca(2+)](i) elevation were up-regulated. The use of specific siRNA showed that the changes of Ca(2+) homeostasis induced by NAD(+) precursors are mediated by CD38 and the consequent ADPR-mediated TRPM2 gating. Finally, the presence of NAD(+) precursors up-regulated important T cell functions, such as proliferation and IL-2 release in response to mitogens.

  3. LmxMPK4, an essential mitogen-activated protein kinase of Leishmania mexicana is phosphorylated and activated by the STE7-like protein kinase LmxMKK5

    DEFF Research Database (Denmark)

    John von Freyend, Simona; Rosenqvist, Heidi; Fink, Annette

    2010-01-01

    The essential mitogen-activated protein kinase (MAP kinase), LmxMPK4, of Leishmania mexicana is minimally active when purified following recombinant expression in Escherichia coli and was therefore unsuitable for drug screening until now. Using an E. coli protein co-expression system we identifie...... for new therapeutic drugs against leishmaniasis....

  4. Self oscillating PWM modulators, a topological comparison

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    's work with switch mode audio power amplifiers, where linear tracking of the reference signal is of major importance. Use of the modulator topologies presented are not limited to this kind of equipment, but can be used in a very wide range of applications from very low to very high power levels....

  5. Subclass of individual IgA-secreting human lymphocytes. Investigation of in vivo pneumococcal polysaccharide-induced and in vitro mitogen-induced blood B cells by monolayer plaque-forming cell assays

    DEFF Research Database (Denmark)

    Heilmann, C; Barington, T; Sigsgaard, T

    1988-01-01

    was recorded among IgA-secreting blood cells in PWM- and EBV-stimulated cultures. In contrast, a predominance of IgA2 (54%) was found among IgA-secreting cells (2531/10(6)) isolated from the blood 7 days after in vivo stimulation with pneumococcal polysaccharides, and a similar proportion (51%) of IgA2...... producing cells was found among IgA anti-pneumococcal polysaccharide-secreting cells. It was thus confirmed that IgA1 is the predominant subclass of blood IgA-secreting cells in general. However, the high percentage of IgA2-secreting cells found after vaccination with pneumococcal polysaccharides suggests...... that these Ag have an unusually high ability to activate IgA2 B cells, or that the B cells stimulated originate from lymphatic tissues with a high frequency of IgA2 committed cells....

  6. Induction of glutathione synthesis in human hepatocytes by acute and chronic arsenic exposure: Differential roles of mitogen-activated protein kinases

    International Nuclear Information System (INIS)

    Hou, Yongyong; Wang, Yi; Wang, Huihui; Xu, Yuanyuan

    2014-01-01

    Highlights: • Arsenic exposure increased intracellular levels of glutathione. • Mitogen-activated protein kinases were involved in glutathione homeostasis. • ERK contributed to glutathione synthesis during acute arsenic exposure. • Glutathione synthesis was regulated by p38 at least in part independent of NRF2 during chronic arsenic exposure. - Abstract: Glutathione (GSH) is a vital component of antioxidant defense which protects cells from toxic insults. Previously we found intracellular GSH was involved in cell resistance against arsenic-induced cytotoxicity. However, molecular mechanisms of GSH homeostasis during arsenic exposure are largely undefined. Here, we investigated roles of mitogen-activated protein kinases (MAPKs) in GSH synthesis pathway with two arsenic exposure strategies by using Chang human hepatocytes. In one strategy, acute arsenic exposure (20 μM, 24 h) was applied, as MAPK signaling is generally considered to be transient. In the other one, chronic arsenic exposure (500 nM, 20 weeks) was applied, which mimicked the general human exposure to arsenic. We found that acute arsenic exposure activated extracellular signal-regulated 1/2 kinases (ERK1/2) and c-Jun N-terminal kinase (JNK) in parallel with increased transcription and nuclear translocation of factor-erythroid 2-related factor 2 (NRF2) and enhanced expression of γ-glutamyl cysteine ligase catalytic subunit (GCLC), resulting in elevated intracellular GSH levels. Specific ERK inhibitor abolished arsenic-induced NRF2 nuclear translocation and GSH synthesis. During chronic arsenic exposure which induced a malignant cellular phenotype, continuous p38 activation and NRF2 nuclear translocation were observed with enhanced GSH synthesis. Specific p38 inhibitor attenuated arsenic-enhanced GSH synthesis without changing NRF2 nuclear translocation. Taken together, our results indicate MAPK pathways play an important role in cellular GSH homeostasis in response to arsenic. However, the

  7. MicroRNA-21 promotes hepatocellular carcinoma HepG2 cell proliferation through repression of mitogen-activated protein kinase-kinase 3

    International Nuclear Information System (INIS)

    Xu, Guangxian; Zhang, Yilin; Wei, Jun; Jia, Wei; Ge, Zhaohui; Zhang, Zhaobo; Liu, Xiaoming

    2013-01-01

    microRNA 21 (miR-21) has been demonstrated to be significantly elevated in many types of cancers, including the hepatocellular carcinoma (HCC). In the present study, we investigated the role of miR-21 in HCC by identifying its novel targets, as well as its underlying molecular mechanism. The expression of mitogen-activated protein kinase-kinase 3 (MAP2K3) in human HCC tumor tissues and adjacent non-tumor tissues was determined by immunohistochemistry staining (IHC) analysis. The 3’-untranslated region (3’-UTR) of MAP2K3 combined with miR-21 was experimentally verified by a miRNA luciferase reporter approach. Moreover, the role of miR-21 in regulating HCC cell proliferation was analyzed by an MTT assay infected with miR-21mimics/sponge inhibitor Adenoviral viral vectors. By immunohistochemistry staining analysis, we found that mitogen-activated protein kinase-kinase 3 (MAP2K3) was strikingly repressed in the human HCC tumor tissues, in comparison with the adjacent non-tumor tissues in clinical settings. More importantly, the repression of MAP2K3 was inversely correlated with the expression of miR-21 in HCC. Further study demonstrated that the MAP2K3 was a novel direct target of miR-21, which was experimentally validated by a miRNA luciferase reporter approach. In HepG2 cells, inhibition of miR-21 expression with an adenoviral miR-21 sponge vector profoundly suppressed cell proliferation by up-regulating MAP2K3 expression at both mRNA and protein levels. These results provide a clinical evidence that MAP2K3 may be a tumor repressor gene, and it is a direct target of miR-21 in HCC, indicating an underlying mechanism by which miR-21 is able to directly target MAP2K3 and inhibit its expression during the carcinogenesis of HCC, at both transcriptional and post-translational levels. This study also suggests that targeting miR-21-MAP2K3 pathway may be a promising strategy in the prevention and treatment of HCC

  8. Role of Akt/PKB and PFKFB isoenzymes in the control of glycolysis, cell proliferation and protein synthesis in mitogen-stimulated thymocytes.

    Science.gov (United States)

    Houddane, Amina; Bultot, Laurent; Novellasdemunt, Laura; Johanns, Manuel; Gueuning, Marie-Agnès; Vertommen, Didier; Coulie, Pierre G; Bartrons, Ramon; Hue, Louis; Rider, Mark H

    2017-06-01

    Proliferating cells depend on glycolysis mainly to supply precursors for macromolecular synthesis. Fructose 2,6-bisphosphate (Fru-2,6-P 2 ) is the most potent positive allosteric effector of 6-phosphofructo-1-kinase (PFK-1), and hence of glycolysis. Mitogen stimulation of rat thymocytes with concanavalin A (ConA) led to time-dependent increases in lactate accumulation (6-fold), Fru-2,6-P 2 content (4-fold), 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase isoenzyme 3 and 4 (PFKFB3 and PFKFB4) protein levels (~2-fold and ~15-fold, respectively) and rates of cell proliferation (~40-fold) and protein synthesis (10-fold) after 68h of incubation compared with resting cells. After 54h of ConA stimulation, PFKFB3 mRNA levels were 45-fold higher than those of PFKFB4 mRNA. Although PFKFB3 could be phosphorylated at Ser461 by protein kinase B (PKB) in vitro leading to PFK-2 activation, PFKFB3 Ser461 phosphorylation was barely detectable in resting cells and only increased slightly in ConA-stimulated cells. On the other hand, PFKFB3 and PFKFB4 mRNA levels were decreased (90% and 70%, respectively) by exposure of ConA-stimulated cells to low doses of PKB inhibitor (MK-2206), suggesting control of expression of the two PFKFB isoenzymes by PKB. Incubation of thymocytes with ConA resulted in increased expression and phosphorylation of the translation factors eukaryotic initiation factor-4E-binding protein-1 (4E-BP1) and ribosomal protein S6 (rpS6). Treatment of ConA-stimulated thymocytes with PFK-2 inhibitor (3PO) or MK-2206 led to significant decreases in Fru-2,6-P 2 content, medium lactate accumulation and rates of cell proliferation and protein synthesis. These data were confirmed by using siRNA knockdown of PFKFB3, PFKFB4 and PKB α/β in the more easily transfectable Jurkat E6-1 cell line. The findings suggest that increased PFKFB3 and PFKFB4 expression, but not increased PFKFB3 Ser461 phosphorylation, plays a role in increasing glycolysis in mitogen

  9. Leptin enhances NR2B-mediated N-methyl-D-aspartate responses via a mitogen-activated protein kinase-dependent process in cerebellar granule cells.

    Science.gov (United States)

    Irving, A J; Wallace, L; Durakoglugil, D; Harvey, J

    2006-01-01

    It is well documented that the hormone leptin regulates energy balance via its actions in the hypothalamus. However, evidence is accumulating that leptin plays a key role in numerous CNS functions. Indeed, leptin receptors are expressed in many extrahypothalamic brain regions, with high levels found in the hippocampus and cerebellum. In the hippocampus leptin has been shown to facilitate N-methyl-D-aspartate receptor function and modulate synaptic plasticity. A role for leptin in cerebellar function is also indicated as leptin-deficient rodents display reduced mobility that is unrelated to obesity. Here we show that leptin receptor immunolabeling can be detected in cultured cerebellar granule cells, being expressed at the somatic plasma membrane and also concentrated at synapses. Furthermore, leptin facilitated NR2B N-methyl-D-aspartate receptor-mediated Ca2+ influx in cerebellar granule cells via a mitogen-activated protein kinase-dependent pathway. These findings provide the first direct evidence for a cellular action of leptin in cerebellar neurons. In addition, given that N-methyl-D-aspartate receptor activity in the cerebellum is crucial for normal locomotor function, these data also have important implications for the potential role of leptin in the control of movement.

  10. Immunomodulatory Activity of Ganoderma atrum Polysaccharide on Purified T Lymphocytes through Ca2+/CaN and Mitogen-Activated Protein Kinase Pathway Based on RNA Sequencing.

    Science.gov (United States)

    Xiang, Quan-Dan; Yu, Qiang; Wang, Hui; Zhao, Ming-Ming; Liu, Shi-Yu; Nie, Shao-Ping; Xie, Ming-Yong

    2017-07-05

    Our previous study has demonstrated that Ganoderma atrum polysaccharide (PSG-1) has immunomodulatory activity on spleen lymphocytes. However, how PSG-1 exerts its effect on purified lymphocytes is still obscure. Thus, this study aimed to investigate the immunomodulatory activity of PSG-1 on purified T lymphocytes and further elucidate the underlying mechanism based on RNA sequencing (RNA-seq). Our results showed that PSG-1 promoted T lymphocytes proliferation and increased the production of IL-2, IFN-γ, and IL-12. Meanwhile, RNA-seq analysis found 394 differentially expressed genes. KEGG pathway analysis identified 20 significant canonical pathways and seven biological functions. Furthermore, PSG-1 elevated intracellular Ca 2+ concentration and calcineurin (CaN) activity and raised the p-ERK, p-JNK, and p-p38 expression levels. T lymphocytes proliferation and the production of IL-2, IFN-γ, and IL-12 were decreased by the inhibitors of calcium channel and mitogen-activated protein kinases (MAPKs). These results indicated that PSG-1 possesses immunomodulatory activity on purified T lymphocytes, in which Ca 2+ /CaN and MAPK pathways play essential roles.

  11. Moringa oleifera fruit induce apoptosis via reactive oxygen species-dependent activation of mitogen-activated protein kinases in human melanoma A2058 cells.

    Science.gov (United States)

    Guon, Tae Eun; Chung, Ha Sook

    2017-08-01

    The present study was performed to determine the effect of Moringa oleifera fruit extract on the apoptosis of human melanoma A2058 cells. A2058 cells were treated for 72 h with Moringa oleifera fruit extract at 50-100 µg/ml, and cell viability with apoptotic changes was examined. The involvement of reactive oxygen species (ROS) and mitogen-activated protein kinases (MAPKs) was examined. It was revealed that Moringa oleifera fruit extract significantly inhibited the cell viability and promoted apoptosis of A2058 cells in a concentration-dependent manner. Moringa oleifera fruit extract-treated A2058 cells exhibited increased activities of cleaved caspase-9 and caspase-3. It also caused an enhancement of MAPK phosphorylation and ROS production. The pro-apoptotic activity of Moringa oleifera fruit extract was significantly reversed by pretreatment with the c-Jun N-terminal kinase (JNK) inhibitor SP600125, extracellular-signal-regulated kinase (ERK) inhibitor PD98058 or ROS inhibitor N-acetyl-L-cysteine. Taken together, Moringa oleifera fruit extract is effective in inducing mitochondrial apoptosis of A2058 cells, which is mediated through induction of ROS formation, and JNK and ERK activation. Moringa oleifera fruit extract may thus have therapeutic benefits for human melanoma A2058 cells.

  12. A p38 Mitogen-Activated Protein Kinase-Regulated Myocyte Enhancer Factor 2–β-Catenin Interaction Enhances Canonical Wnt Signaling

    Science.gov (United States)

    Ehyai, Saviz; Dionyssiou, Mathew G.; Gordon, Joseph W.; Williams, Declan; Siu, K. W. Michael

    2015-01-01

    Canonical Wnt/β-catenin signaling plays a major role in various biological contexts, such as embryonic development, cell proliferation, and cancer progression. Previously, a connection between p38 mitogen-activated protein kinase (MAPK) signaling and Wnt-mediated activation of β-catenin was implied but poorly understood. In the present study, we investigated potential cross talk between p38 MAPK and Wnt/β-catenin signaling. Here we show that a loss of p38 MAPK α/β function reduces β-catenin nuclear accumulation in Wnt3a-stimulated primary vascular smooth muscle cells (VSMCs). Conversely, active p38 MAPK signaling increases β-catenin nuclear localization and target gene activity in multiple cell types. Furthermore, the effect of p38 MAPK α/β on β-catenin activity is mediated through phosphorylation of a key p38 MAPK target, myocyte enhancer factor 2 (MEF2). Here we report a p38 MAPK-mediated, phosphorylation-dependent interaction between MEF2 and β-catenin in multiple cell types and primary VSMCs that results in (i) increased β-catenin nuclear retention, which is reversed by small interfering RNA (siRNA)-mediated MEF2 gene silencing; (ii) increased activation of MEF2 and Wnt/β-catenin target genes; and (iii) increased Wnt-stimulated cell proliferation. These observations provide mechanistic insight into a fundamental level of cross talk between p38 MAPK/MEF2 signaling and canonical Wnt signaling. PMID:26552705

  13. Inhibition of p38 mitogen-activated protein kinase attenuates butyrate-induced intestinal barrier impairment in a Caco-2 cell monolayer model.

    Science.gov (United States)

    Huang, Xiao-Zhong; Li, Zhong-Rong; Zhu, Li-Bin; Huang, Hui-Ya; Hou, Long-Long; Lin, Jing

    2014-08-01

    Butyrate is well known to induce apoptosis in differentiating intestinal epithelial cells. The present study was designed to examine the role of p38 mitogen-activated protein kinase (MAPK) in butyrate-induced intestinal barrier impairment. The intestinal barrier was determined by measuring the transepithelial electrical resistance (TER) in a Caco-2 cell monolayer model. The permeability was determined by measuring transepithelial passage of fluorescein isothiocyanate-conjugated inulin (inulin-FITC). The morphology of the monolayers was examined with scanning electron microscopy. The apoptosis status was determined by annexin V-FITC labeling and flow cytometry. The activity of p38 MAPK was determined by the phosphorylation status of p38 with Western blotting. Butyrate at 5 mM increases the apoptosis rate of Caco-2 cells and induces impairment of intestinal barrier functions as determined by decreased TER and increased inulin-FITC permeability. Butyrate treatment activates p38 MAPK in a concentration- and time-dependent manner. SB203580, a specific p38 inhibitor, inhibits butyrate-induced Caco-2 cell apoptosis. Treatment of SB203580 significantly attenuates the butyrate-induced impairment of barrier functions in the Caco-2 cell monolayer model. p38 MAPK can be activated by butyrate and is involved in the butyrate-induced apoptosis and impairment of intestinal barrier function. Inhibition of p38 MAPK can significantly attenuate butyrate-induced intestinal barrier dysfunction.

  14. Involvement of mitogen-activated protein kinases and NFκB in LPS-induced CD40 expression on human monocytic cells

    International Nuclear Information System (INIS)

    Wu Weidong; Alexis, Neil E.; Chen Xian; Bromberg, Philip A.; Peden, David B.

    2008-01-01

    CD40 is a costimulatory molecule linking innate and adaptive immune responses to bacterial stimuli, as well as a critical regulator of functions of other costimulatory molecules. The mechanisms regulating lipopolysaccharide (LPS)-induced CD40 expression have not been adequately characterized in human monocytic cells. In this study we used a human monocytic cell line, THP-1, to investigate the possible mechanisms of CD40 expression following LPS exposure. Exposure to LPS resulted in a dose- and time-dependent increase in CD40 expression. Further studies using immunoblotting and pharmacological inhibitors revealed that mitogen-activated protein kinases (MAPKs) and NFκB were activated by LPS exposure and involved in LPS-induced CD40 expression. Activation of MAPKs was not responsible for LPS-induced NFκB activation. TLR4 was expressed on THP-1 cells and pretreatment of cells with a Toll-like receptor 4 (TLR4) neutralizing antibody (HTA125) significantly blunted LPS-induced MAPK and NFκB activation and ensuing CD40 expression. Additional studies with murine macrophages expressing wild type and mutated TLR4 showed that TLR4 was implicated in LPS-induced ERK and NFκB activation, and CD40 expression. Moreover, blockage of MAPK and NFκB activation inhibited LPS-induced TLR4 expression. In summary, LPS-induced CD40 expression in monocytic cells involves MAPKs and NFκB

  15. Acetylcorynoline impairs the maturation of mouse bone marrow-derived dendritic cells via suppression of IκB kinase and mitogen-activated protein kinase activities.

    Directory of Open Access Journals (Sweden)

    Ru-Huei Fu

    Full Text Available BACKGROUND: Dendritic cells (DCs are major modulators in the immune system. One active field of research is the manipulation of DCs as pharmacological targets to screen novel biological modifiers for the treatment of inflammatory and autoimmune disorders. Acetylcorynoline is the major alkaloid component derived from Corydalis bungeana herbs. We assessed the capability of acetylcorynoline to regulate lipopolysaccharide (LPS-stimulated activation of mouse bone marrow-derived DCs. METHODOLOGY/PRINCIPAL FINDINGS: Our experimental data showed that treatment with up to 20 µM acetylcorynoline does not cause cytotoxicity in cells. Acetylcorynoline significantly inhibited the secretion of tumor necrosis factor-α, interleukin-6, and interleukin-12p70 by LPS-stimulated DCs. The expression of LPS-induced major histocompatibility complex class II, CD40, and CD86 on DCs was also decreased by acetylcorynoline, and the endocytic capacity of LPS-stimulated DCs was restored by acetylcorynoline. In addition, LPS-stimulated DC-elicited allogeneic T-cell proliferation was blocked by acetylcorynoline, and the migratory ability of LPS-stimulated DCs was reduced by acetylcorynoline. Moreover, acetylcorynoline significantly inhibits LPS-induced activation of IκB kinase and mitogen-activated protein kinase. Importantly, administration of acetylcorynoline significantly attenuates 2,4-dinitro-1-fluorobenzene-induced delayed-type hypersensitivity. CONCLUSIONS/SIGNIFICANCE: Acetylcorynoline may be one of the potent immunosuppressive agents through the blockage of DC maturation and function.

  16. The Role of Unfolded Protein Response and Mitogen-Activated Protein Kinase Signaling in Neurodegenerative Diseases with Special Focus on Prion Diseases

    Directory of Open Access Journals (Sweden)

    Lifeng Yang

    2017-05-01

    Full Text Available Prion diseases are neurodegenerative pathologies characterized by the accumulation of a protease-resistant form of the cellular prion protein named prion protein scrapie (PrPSc in the brain. PrPSc accumulation in the endoplasmic reticulum (ER result in a dysregulated calcium (Ca2+ homeostasis and subsequent initiation of unfolded protein response (UPR leading to neuronal dysfunction and apoptosis. The molecular mechanisms for the transition between adaptation to ER stress and ER stress-induced apoptosis are still unclear. Mitogen-activated protein kinases (MAPKs are serine/threonine protein kinases that rule the signaling of many extracellular stimuli from plasma membrane to the nucleus. However the identification of numerous points of cross talk between the UPR and MAPK signaling pathways may contribute to our understanding of the consequences of ER stress in prion diseases. Indeed the MAPK signaling network is known to regulate cell cycle progression and cell survival or death responses following a variety of stresses including misfolded protein response stress. In this article, we review the UPR signaling in prion diseases and discuss the triad of MAPK signaling pathways. We also describe the role played by MAPK signaling cascades in Alzheimer’s (AD and Parkinson’s disease (PD. We will also overview the mechanisms of cell death and the role of MAPK signaling in prion disease progression and highlight potential avenues for therapeutic intervention.

  17. The pmk1-like mitogen-activated protein kinase from Lecanicillium (Verticillium) fungicola is not required for virulence on Agaricus bisporus.

    Science.gov (United States)

    Collopy, Patrick D; Amey, Richard C; Sergeant, Martin J; Challen, Michael P; Mills, Peter R; Foster, Gary D; Bailey, Andy M

    2010-05-01

    In plant-pathogenic fungi, the pmk1 mitogen-activated protein kinase (MAPK) signalling pathway plays an essential role in regulating the development of penetration structures and the sensing of host-derived cues, but its role in other pathosystems such as fungal-fungal interactions is less clear. We report the use of a gene disruption strategy to investigate the pmk1-like MAPK, Lf pmk1 in the development of Lecanicillium fungicola (formerly Verticillium fungicola) infection on the cultivated mushroom Agaricus bisporus. Lf pmk1 was isolated using a degenerate PCR-based approach and was shown to be present in a single copy by Southern blot analysis. Quantitative RT-PCR showed the transcript to be fivefold upregulated in cap lesions compared with pure culture. Agrobacterium-mediated targeted disruption was used to delete a central portion of the Lf pmk1 gene. The resulting mutants showed normal symptom development as assessed by A. bisporus mushroom cap assays, sporulation patterns were normal and there were no apparent changes in overall growth rates. Our results indicate that, unlike the situation in fungal-plant pathogens, the pmk1-like MAPK pathway is not required for virulence in the fungal-fungal interaction between the L. fungicola pathogen and A. bisporus host. This observation may be of wider significance in other fungal-fungal and/or fungal-invertebrate interactions.

  18. Immunomodulatory Efficacy of Standardized Annona muricata (Graviola) Leaf Extract via Activation of Mitogen-Activated Protein Kinase Pathways in RAW 264.7 Macrophages

    Science.gov (United States)

    2016-01-01

    Annona muricata, commonly known as Graviola, has been utilized as a traditional medicine to treat various human diseases. The aim of this study was to examine the immune-enhancing activity of Graviola leaf extracts in RAW 264.7 macrophage cells. Active ingredients in Graviola leaf extracts (GE) were identified as kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside by LC-MS/MS. When treated with steam or 50% ethanol GE, cell morphology was altered due to initiation of cell differentiation. While the cell viability was not altered by the steam GE, it was reduced by the ethanol GE. Both steam and ethanol GE induced the transcriptional expression of cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-1β, but only the steam extract upregulated inducible nitric oxide synthase (iNOS). In consistence with mRNA expression, the production of TNF-α and nitrite was elevated by both steam and ethanol extracts of Graviola leaves. This is mainly due to activation of mitogen-activated protein (MAP) kinase signaling pathways. These results suggest that Graviola leaves enhance immunity by activation of the MAP kinase pathways. These bioactive properties of Graviola indicate its potential as a health-promoting ingredient to boost the immune system. PMID:28096884

  19. Genome-Wide Identification of Mitogen-Activated Protein Kinase Gene Family across Fungal Lineage Shows Presence of Novel and Diverse Activation Loop Motifs.

    Directory of Open Access Journals (Sweden)

    Tapan Kumar Mohanta

    Full Text Available The mitogen-activated protein kinase (MAPK is characterized by the presence of the T-E-Y, T-D-Y, and T-G-Y motifs in its activation loop region and plays a significant role in regulating diverse cellular responses in eukaryotic organisms. Availability of large-scale genome data in the fungal kingdom encouraged us to identify and analyse the fungal MAPK gene family consisting of 173 fungal species. The analysis of the MAPK gene family resulted in the discovery of several novel activation loop motifs (T-T-Y, T-I-Y, T-N-Y, T-H-Y, T-S-Y, K-G-Y, T-Q-Y, S-E-Y and S-D-Y in fungal MAPKs. The phylogenetic analysis suggests that fungal MAPKs are non-polymorphic, had evolved from their common ancestors around 1500 million years ago, and are distantly related to plant MAPKs. We are the first to report the presence of nine novel activation loop motifs in fungal MAPKs. The specificity of the activation loop motif plays a significant role in controlling different growth and stress related pathways in fungi. Hence, the presences of these nine novel activation loop motifs in fungi are of special interest.

  20. Immunomodulatory Efficacy of Standardized Annona muricata (Graviola Leaf Extract via Activation of Mitogen-Activated Protein Kinase Pathways in RAW 264.7 Macrophages

    Directory of Open Access Journals (Sweden)

    Goon-Tae Kim

    2016-01-01

    Full Text Available Annona muricata, commonly known as Graviola, has been utilized as a traditional medicine to treat various human diseases. The aim of this study was to examine the immune-enhancing activity of Graviola leaf extracts in RAW 264.7 macrophage cells. Active ingredients in Graviola leaf extracts (GE were identified as kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside by LC-MS/MS. When treated with steam or 50% ethanol GE, cell morphology was altered due to initiation of cell differentiation. While the cell viability was not altered by the steam GE, it was reduced by the ethanol GE. Both steam and ethanol GE induced the transcriptional expression of cytokines, including tumor necrosis factor-α (TNF-α and interleukin-1β, but only the steam extract upregulated inducible nitric oxide synthase (iNOS. In consistence with mRNA expression, the production of TNF-α and nitrite was elevated by both steam and ethanol extracts of Graviola leaves. This is mainly due to activation of mitogen-activated protein (MAP kinase signaling pathways. These results suggest that Graviola leaves enhance immunity by activation of the MAP kinase pathways. These bioactive properties of Graviola indicate its potential as a health-promoting ingredient to boost the immune system.

  1. Immunomodulatory Efficacy of Standardized Annona muricata (Graviola) Leaf Extract via Activation of Mitogen-Activated Protein Kinase Pathways in RAW 264.7 Macrophages.

    Science.gov (United States)

    Kim, Goon-Tae; Tran, Nguyen Khoi Song; Choi, Eun-Hye; Song, Yoo-Jeong; Song, Jae-Hwi; Shim, Soon-Mi; Park, Tae-Sik

    2016-01-01

    Annona muricata , commonly known as Graviola, has been utilized as a traditional medicine to treat various human diseases. The aim of this study was to examine the immune-enhancing activity of Graviola leaf extracts in RAW 264.7 macrophage cells. Active ingredients in Graviola leaf extracts (GE) were identified as kaempferol-3-O-rutinoside and quercetin-3-O-rutinoside by LC-MS/MS. When treated with steam or 50% ethanol GE, cell morphology was altered due to initiation of cell differentiation. While the cell viability was not altered by the steam GE, it was reduced by the ethanol GE. Both steam and ethanol GE induced the transcriptional expression of cytokines, including tumor necrosis factor- α (TNF- α ) and interleukin-1 β , but only the steam extract upregulated inducible nitric oxide synthase (iNOS). In consistence with mRNA expression, the production of TNF- α and nitrite was elevated by both steam and ethanol extracts of Graviola leaves. This is mainly due to activation of mitogen-activated protein (MAP) kinase signaling pathways. These results suggest that Graviola leaves enhance immunity by activation of the MAP kinase pathways. These bioactive properties of Graviola indicate its potential as a health-promoting ingredient to boost the immune system.

  2. Analysis of the mitogenic pathway of the FLT3 receptor and characterization in its C terminal region of a specific binding site for the PI3' kinase.

    Science.gov (United States)

    Casteran, N; Rottapel, R; Beslu, N; Lecocq, E; Birnbaum, D; Dubreuil, P

    1994-05-01

    The FLT3 receptor tyrosine kinase (RTK) belongs to the class III subfamily which includes PDGF, CSF1 and SLF receptors. The recent cloning of the FLT3 ligand suggesting its important role in the differentiation and proliferation of the hematopoietic stem cells, has confirmed the initial expression analysis showing restricted pattern of receptor expression within the primitive hematopoietic population. To better understand the function of the FLT3 receptor and its relationship with the other hematopoietic RTKs, we analyzed the mitogenic pathway and substrate specificity of this receptor. The construction of a chimeric receptor called FF3, between the extracellular region of the CSF1 receptor fused with the transmembrane and the cytoplasmic regions of FLT3, has allowed an analysis in the absence of FLT3 ligand. We have shown in previous studies that FF3 is able to transduce the signal induced by CSF1, to induce tyrosine phosphorylation and/or association of several cytoplasmic proteins. We show here that this new receptor is fully functional in Ba/F3 hematopoietic cells, inducing a CSF1 dependence when expressed at the surface of this IL3 dependent cell line. The PI3' Kinase interacts with the FF3 receptor through SH2 domains and its binding site is localized on the tyrosine residue 958 in the C terminal part of the receptor.

  3. Role of mitogen-activated protein kinases in endothelin ETB receptor up-regulation after organ culture of rat mesenteric artery

    DEFF Research Database (Denmark)

    Uddman, Erik; Henriksson, Marie; Eskesen, Karen

    2003-01-01

    Organ culture of isolated arteries results in increased levels of endothelin ET(B) (ET(B)) receptor mRNA and in enhanced ET(B) receptor mediated contraction. The present study was designed to pinpoint the mitogen-activated protein kinase (MAPK) subtype involved in up-regulation of ET(B) receptors...... after organ culture of rat mesenteric arteries. Western blot and selective antibodies towards constitutional and phosphorylated MAPKs revealed the appearance of phosphorylated MAPK of the extracellular signal-regulated kinases (ERK) 1/2 type at 3 h of organ culture. The functional ET(B) receptor and its...... mRNA expression were up-regulated after 24 h of organ culture. Following incubation with the MEK 1/2 specific inhibitor SB408039 or the raf inhibitor SB386023b the up-regulation was attenuated both for ET(B) receptor responses and in ET(B) receptor mRNA expression in the vessel segments. Neither...

  4. Human chorionic gonadotropin stimulates spheroid attachment on fallopian tube epithelial cells through the mitogen-activated protein kinase pathway and down-regulation of olfactomedin-1.

    Science.gov (United States)

    So, Kam-Hei; Kodithuwakku, Suranga P; Kottawatta, Kottawattage S A; Li, Raymond H W; Chiu, Philip C N; Cheung, Annie N Y; Ng, Ernest H Y; Yeung, William S B; Lee, Kai-Fai

    2015-08-01

    To study the effect of human chorionic gonadotropin (hCG) on olfactomedin-1 (Olfm1) expression and spheroid attachment in human fallopian tube epithelial cells in vitro. Experimental study. Reproductive biology laboratory. Healthy nonpregnant women. No patient interventions. Luteinizing hormone/chorionic gonadotropin receptor (LHCGR) and Olfm1 expression in fallopian tube epithelium cell line (OE-E6/E7 cells). OE-E6/E7 cells treated with hCG, U0126 extracellular signal-regulated kinase (ERK) inhibitor, or XAV939 Wnt/β-catenin inhibitor were analyzed by Western blotting, real-time polymerase chain reaction, and in vitro spheroid attachment assay. Human chorionic gonadotropin increased spheroid attachment on OE-E6/E7 cells through down-regulation of Olfm1 and activation of Wnt and mitogen-activated protein kinase (MAPK) signaling pathways. U0126 down-regulated both MAPK and Wnt/β-catenin signaling pathways and up-regulated Olfm1 expression. XAV939 down-regulated only the Wnt/β-catenin signaling pathway but up-regulated Olfm1 expression. Human chorionic gonadotropin activated both ERK and Wnt/β-catenin signaling pathways and enhanced spheroid attachment on fallopian tube epithelial cells through down-regulation of Olfm1 expression. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  5. Mouse model of testosterone-induced muscle fiber hypertrophy: involvement of p38 mitogen-activated protein kinase-mediated Notch signaling.

    Science.gov (United States)

    Brown, Danielle; Hikim, Amiya P Sinha; Kovacheva, Ekaterina L; Sinha-Hikim, Indrani

    2009-04-01

    As a prerequisite for studies using mutant mice, we established a mouse model for investigating the molecular mechanisms by which testosterone (T) promotes muscle growth. Groups of six adult male mice (C57BL/6) received one of the following treatments: 1) vehicle (sterile distilled water; normal control) and 2) GnRH antagonist with empty (sham control) or 2 cm T- filled implant. Mice were killed 2, 6, and 8 weeks after treatment. T treatment for 8 weeks resulted in a significant (Phypertrophy was accompanied by up-regulation of the Notch ligand Delta 1 and activation of Notch signaling, as evidenced by increase in activated forms of Notch 1 and Notch 2. Consistent with this, we also observed an increase in the number of proliferating cell nuclear antigen (PCNA)-positive nuclei in muscles of T-treated mice, indicating that activation of Notch signaling enhanced cell proliferation. T supplementation not only triggered p38 mitogen-activated protein kinase (MAPK) activation but also concurrently inhibited c-Jun NH(2)-terminal kinase (JNK) activation within 2 weeks of treatment. Concomitant administration of SB203580, a p38 MAPK inhibitor, effectively blocked T-induced activation of Notch signaling and significantly (Phypertrophy through activation of Notch signaling and the inactivation of JNK together with the activation of p38 MAPK may be critical for T-induced activation of Notch signaling and, as a consequence, muscle fiber hypertrophy.

  6. Enhancement in irradiated mononuclear cells in culture of mitogen-induced incorporation of [3H]thymidine by homologous conditioned medium

    International Nuclear Information System (INIS)

    Sandru, G.; Greiner, R.

    1994-01-01

    Incorporation of [ 3 H]thymidine in irradiated peripheral blood mononuclear cell cultures irradiated in vitro was stimulated significantly by either concanavalin A or phytohemagglutinin only in the presence of homologous conditioned medium. Production of this activity by mononuclear cells was enhanced by irradiation and/or pulsed exposure to puromycin but was abolished by actinomycin D. Addition of anti-interleukin 1 or anti-interleukin 2 monoclonal antibodies to the conditioned medium before assay did not influence the stimulatory action. A similar significant stimulation of mononuclear cell cultures irradiated with 6 Gy by concanavalin A was obtained when purified preparations of homologous conditioned medium were used in the assay. Purification was done by ultrafiltration and concentration, heparin agarose chromatography, ammonium sulfate precipitation, concanavalin A agarose chromatography, DEAE-ion exchange chromatography and HPLC gel filtration chromatography. With SDS-PAGE and silver staining, the active HPLC fraction gave one band of 50 kDa, suggesting that this protein is responsible for the co-stimulatory effect of homologous conditioned medium for both mitogen-induced irradiated and nonirradiated mononuclear cell cultures. 42 refs., 9 figs., 3 tabs

  7. Premature chromosome condensation in human resting peripheral blood lymphocytes without mitogen stimulation for chromosome aberration analysis using specific whole chromosome DNA hybridization probes.

    Science.gov (United States)

    Pathak, Rupak; Prasanna, Pataje G S

    2014-01-01

    We have previously described a unique, simple, and rapid method for inducing premature chromosome condensation (PCC) in "resting" human peripheral blood lymphocytes (HPBLs) without mitogen stimulation and an approach for studying numerical changes and/or structural aberrations involving a specific pair of human chromosomes. The current protocol incorporates improvements that provide better PCC, incorporates a high-throughput automated sample preparation unit and metaphase harvester to minimize manual labor and improve quality, and supports simultaneous painting of multiple sets of human autosomes in interphase nuclei. To induce PCC, isolated HPBLs are incubated at 37 °C in cell culture medium supplemented with a phosphatase inhibitor (okadaic acid or calyculin A), adenosine triphosphate, and p34(cdc2)/cyclin B kinase (an essential component of mitosis-promoting factor) for a short period of time. PCC spreads are prepared on glass slides using a humidity- and temperature-controlled chamber (an auto-spreader) after a brief hypotonic treatment and fixation. Aberrations involving specific sets of painted human chromosome are analyzed using fluorescence microscopy. Each of the normal (undamaged) painted homologous chromosome pairs displays two fluorescent spots, whereas cells with numerical and/or structural aberration involving specific painted chromosome sets show deviation in the number of fluorescent spots. The identification and quantification of aberration involving specific chromosomes in interphase nuclei have important applications in radiobiology, toxicology, radiation therapeutics, and cancer research.

  8. The mitogen-activated protein kinase GlSlt2 regulates fungal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in Ganoderma lucidum.

    Science.gov (United States)

    Zhang, Guang; Sun, Zehua; Ren, Ang; Shi, Liang; Shi, Dengke; Li, Xiongbiao; Zhao, Mingwen

    2017-07-01

    The mitogen-activated protein kinases (MAPKs) are crucial signaling instruments in eukaryotes that play key roles in regulating fungal growth, development, and secondary metabolism and in adapting to the environment. In this study, we characterized an Slt2-type MAPK in Ganoderma lucidum, GlSlt2, which was transcriptionally induced during the primordium and fruiting body stages. RNA interference was used to examine the function of GlSlt2. Knockdown of GlSlt2 caused defects in growth and increased hyphal branching as well as hypersensitivity to cell wall-disturbing substances. Consistently, the chitin and β-1,3-d-glucan contents and the expression of cell wall biosynthesis genes were decreased and down-regulated, respectively, in GlSlt2 knockdown strains compared with those in the wild type (WT). In addition, no primordium or fruiting body could be observed in GlSlt2 knockdown strains. Furthermore, the intracellular reactive oxygen species (ROS) content and ganoderic acid biosynthesis also decreased in GlSlt2 knockdown strains. Addition of H 2 O 2 could recover the decreased ganoderic acid content in GlSlt2 knockdown strains, indicating that GlSlt2 might regulate ganoderic acid biosynthesis via the intracellular ROS level. Overall, GlSlt2 is involved in hyphal growth, fruiting body development, cell wall integrity, oxidative stress and ganoderic acid biosynthesis in G. lucidum. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Ethanol extract of the seed of Zizyphus jujuba var. spinosa potentiates hippocampal synaptic transmission through mitogen-activated protein kinase, adenylyl cyclase, and protein kinase A pathways.

    Science.gov (United States)

    Jo, So Yeon; Jung, In Ho; Yi, Jee Hyun; Choi, Tae Joon; Lee, Seungheon; Jung, Ji Wook; Yun, Jeanho; Lee, Young Choon; Ryu, Jong Hoon; Kim, Dong Hyun

    2017-03-22

    As the seed of Zizyphus jujuba var. spinosa (Bunge) Hu ex H.F. Chow (Rhamnaceae) has been used to sleep disturbances in traditional Chinese and Korean medicine, many previous studies have focused on its sedative effect. Recently, we reported the neuroprotective effect of the effect of Z. jujuba var. spinosa. However, its effects on synaptic function have not yet been studied. In this project, we examined the action of ethanol extract of the seed of Z. jujuba var. spinosa (DHP1401) on synaptic transmission in the hippocampus. To investigate the effects of DHP1401, field recordings were conducted using hippocampal slices (400µm). Object recognition test was introduced to examine whether DHP1401 affect normal recognition memory. DHP1401 (50μg/ml) induced a significant increase in synaptic activity in Shaffer collateral pathway in a concentration-dependent manner. This increase of synaptic responses was blocked by NBQX, a broad spectrum α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist, but not IEM-1460, a Ca 2+ -permeable AMPAR blocker. Moreover, U0126, a mitogen-activated protein kinase inhibitor, SQ22536, an adenylyl cyclase inhibitor, and PKI, a protein kinase A inhibitor, blocked DHP1401-induced increase in synaptic transmission. Finally, DHP1401 facilitated object recognition memory. These results suggest that DHP1401 increase synaptic transmission through increase of synaptic AMPAR transmission via MAPK, AC and PAK. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  10. Excessive L-cysteine induces vacuole-like cell death by activating endoplasmic reticulum stress and mitogen-activated protein kinase signaling in intestinal porcine epithelial cells.

    Science.gov (United States)

    Ji, Yun; Wu, Zhenlong; Dai, Zhaolai; Sun, Kaiji; Zhang, Qing; Wu, Guoyao

    2016-01-01

    High intake of dietary cysteine is extremely toxic to animals and the underlying mechanism remains largely unknown. This study was conducted to test the hypothesis that excessive L-cysteine induces cell death by activating endoplasmic reticulum (ER) stress and mitogen-activated protein kinase (MAPK) signaling in intestinal porcine epithelial cells. Jejunal enterocytes were cultured in the presence of 0-10 mmol/L L-cysteine. Cell viability, morphologic alterations, mRNA levels for genes involved in ER stress, protein abundances for glucose-regulated protein 78, C/EBP homologous protein (CHOP), alpha subunit of eukaryotic initiation factor-2 (eIF2α), extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and c-Jun N-terminal protein kinase (JNK1/2) were determined. The results showed that L-cysteine (5-10 mmol/L) reduced cell viability (P cysteine were not affected by the autophagy inhibitor 3-methyladenine. The protein abundances for CHOP, phosphorylated (p)-eIF2α, p-JNK1/2, p-p38 MAPK, and the spliced form of XBP-1 mRNA were enhanced (P cysteine induces vacuole-like cell death via the activation of ER stress and MAPK signaling in small intestinal epithelial cells. These signaling pathways may be potential targets for developing effective strategies to prevent the toxicity of dietary cysteine.

  11. ZmMKK4, a novel group C mitogen-activated protein kinase kinase in maize (Zea mays), confers salt and cold tolerance in transgenic Arabidopsis.

    Science.gov (United States)

    Kong, Xiangpei; Pan, Jiaowen; Zhang, Maoying; Xing, Xin; Zhou, Yan; Liu, Yang; Li, Dapeng; Li, Dequan

    2011-08-01

    Mitogen-activated protein kinase (MAPK) cascades are signalling modules that transduce extracellular signalling to a range of cellular responses. Plant MAPK cascades have been implicated in development and stress response. In this study, we isolated a novel group C MAPKK gene, ZmMKK4, from maize. Northern blotting analysis revealed that the ZmMKK4 transcript expression was up-regulated by cold, high salt and exogenous H(2)O(2,) but down-regulated by exogenous abscisic acid (ABA). Over-expression of ZmMKK4 in Arabidopsis conferred tolerance to cold and salt stresses by increased germination rate, lateral root numbers, plant survival rate, chlorophyll, proline and soluble sugar contents, and antioxidant enzyme [peroxidase (POD), catalase (CAT)] activities compared with control plants. Furthermore, ZmMKK4 enhanced a 37 kDa kinase activity after cold and salt stresses. RT-PCR analysis revealed that the transcript levels of stress-responsive transcription factors and functional genes were higher in ZmMKK4-over-expressing plants than in control plants. In addition, ZmMKK4 protein is localized in the nucleus. Taken together, these results indicate that ZmMKK4 is a positive regulator of salt and cold tolerance in plants. © 2011 Blackwell Publishing Ltd.

  12. Buddleja officinalis suppresses high glucose-induced vascular smooth muscle cell proliferation: role of mitogen-activated protein kinases, nuclear factor-kappaB and matrix metalloproteinases.

    Science.gov (United States)

    Lee, Yun Jung; Kim, Jin Sook; Kang, Dae Gill; Lee, Ho Sub

    2010-02-01

    Diabetes mellitus is a well-established risk factor for vascular diseases caused by atherosclerosis. In the development of diabetic atherogenesis, vascular smooth muscle cell proliferation is recognized as a key event. Thus, we aimed to investigate whether an ethanol extract of Buddleja officinalis (EBO) suppresses high glucose-induced proliferation in primary cultured human aortic smooth muscle cells (HASMC). [(3)H]-thymidine incorporation revealed that incubation of HASMC with a high concentration of glucose (25 mmol/L) increased cell proliferation. The expression levels of cell cycle protein were also increased by treatment with high glucose concentration. Pretreatment of HASMC with EBO significantly attenuated the increase of high glucose-induced cell proliferation as well as p38 mitogen-activated protein kinases (MAPK) and JNK phosphorylation. EBO suppressed high glucose-induced matrix metalloproteinase (MMP)-9 activity in a dose-dependent manner. In addition, EBO suppressed nuclear factor-kappaB (NF-kappaB) nuclear translocation and transcriptional activity in high glucose conditions. Taken together, the present data suggest that EBO could suppress high glucose-induced atherosclerotic processes through inhibition of p38, JNK, NF-kappaB and MMP signal pathways in HASMC.

  13. Stress-Stimulated Mitogen-Activated Protein Kinases Control the Stability and Activity of the Cdt1 DNA Replication Licensing Factor ▿

    Science.gov (United States)

    Chandrasekaran, Srikripa; Tan, Ting Xu; Hall, Jonathan R.; Cook, Jeanette Gowen

    2011-01-01

    DNA replication is tightly coordinated both with cell cycle cues and with responses to extracellular signals to maintain genome stability. We discovered that human Cdt1, an essential origin licensing protein whose activity must be restricted to G1 phase, is a substrate of the stress-activated mitogen-activated protein (MAP) kinases p38 and c-Jun N-terminal kinase (JNK). These MAP kinases phosphorylate Cdt1 both during unperturbed G2 phase and during an acute stress response. Phosphorylation renders Cdt1 resistant to ubiquitin-mediated degradation during S phase and after DNA damage by blocking Cdt1 binding to the Cul4 adaptor, Cdt2. Mutations that block normal cell cycle-regulated MAP kinase-mediated phosphorylation interfere with rapid Cdt1 reaccumulation at the end of S phase. Phosphomimetic mutations recapitulate the stabilizing effects of Cdt1 phosphorylation but also reduce the ability of Cdt1 to support origin licensing. Two other CRL4Cdt2 targets, the cyclin-dependent kinase (CDK) inhibitor p21 and the methyltransferase PR-Set7/Set8, are similarly stabilized by MAP kinase activity. These findings support a model in which MAP kinase activity in G2 promotes reaccumulation of a low-activity Cdt1 isoform after replication is complete. PMID:21930785

  14. Arabidopsis thaliana mitogen-activated protein kinase 6 is involved in seed formation and modulation of primary and lateral root development.

    Science.gov (United States)

    López-Bucio, J S; Dubrovsky, J G; Raya-González, J; Ugartechea-Chirino, Y; López-Bucio, J; de Luna-Valdez, L A; Ramos-Vega, M; León, P; Guevara-García, A A

    2014-01-01

    Mitogen-activated protein kinase (MAPKs) cascades are signal transduction modules highly conserved in all eukaryotes regulating various aspects of plant biology, including stress responses and developmental programmes. In this study, we characterized the role of MAPK 6 (MPK6) in Arabidopsis embryo development and in post-embryonic root system architecture. We found that the mpk6 mutation caused altered embryo development giving rise to three seed phenotypes that, post-germination, correlated with alterations in root architecture. In the smaller seed class, mutant seedlings failed to develop the primary root, possibly as a result of an earlier defect in the division of the hypophysis cell during embryo development, but they had the capacity to develop adventitious roots to complete their life cycle. In the larger class, the MPK6 loss of function did not cause any evident alteration in seed morphology, but the embryo and the mature seed were bigger than the wild type. Seedlings developed from these bigger seeds were characterized by a primary root longer than that of the wild type, accompanied by significantly increased lateral root initiation and more and longer root hairs. Apparently, the increment in primary root growth resulted from an enhanced cell production and cell elongation. Our data demonstrated that MPK6 plays an important role during embryo development and acts as a repressor of primary and lateral root development.

  15. The use of a spaceflight-compatible device to perform WBC surface marker staining and whole-blood mitogenic activation for cytokine detection by flow cytometry

    Science.gov (United States)

    Crucian, B. E.; Sams, C. F.

    1999-01-01

    Significant changes have recently been described regarding circulating peripheral immune cells immediately following spaceflight. Existing methods for immunophenotype staining of peripheral blood in terrestrial labs do not meet the constraints for flight on the Space Shuttle. We have recently described the development and use of the Whole Blood Staining Device (WBSD), a simple device for staining flow cytometry specimens during spaceflight. When preparing samples with the WBSD, all liquids are safely contained as the cells are moved through staining, lysis and fixation steps. Here we briefly review the use of the WBSD, and then describe another versatile adaptation, a modification to perform intracellular staining of cytokines for detection by flow cytometry. Alterations in cytokine production have been reported both in ground-based simulated microgravity culture and in astronaut samples returning from spaceflight. Data regarding microgravity effects on cytokine production for specific subpopulations of cells is lacking. Flow cytometric cytokine analysis offers the unique ability to perform simultaneous surface marker analysis and positively identity cytokine producing subsets of cells. The utilization of the WBSD provides the ability to perform rapid and routine mitogenic activation during spaceflight coupled with the ability to perform simultaneous surface marker analysis. The only external requirements for this procedure are an in-flight 37-degree incubator and the capacity for 4-degree storage.

  16. Induction of protection against paraquat-induced oxidative damage by abscisic acid in maize leaves is mediated through mitogen-activated protein kinase.

    Science.gov (United States)

    Ding, Hai-Dong; Zhang, Xiao-Hua; Xu, Shu-Cheng; Sun, Li-Li; Jiang, Ming-Yi; Zhang, A-Ying; Jin, Yin-Gen

    2009-10-01

    Mitogen-activated protein kinase (MAPK) cascade has been shown to be important components in stress signal transduction pathway. In the present study, protection of maize seedlings (Zea mays L.) against paraquat-generated oxidative toxicity by abscisic acid (ABA), its association with MAPK and ZmMPK5, a candidate for MAPK were investigated. Treatment of maize leaves with exogenous ABA led to significant decreases in the content of malondialdehyde, the percentage of ion leakage and the level of protein oxidation (in terms of carbonyl groups) under paraquat (PQ) stress. However, such decreases were blocked by the pretreatment with two MAPK kinase inhibitors PD98059 and U0126. The damage caused by PQ was further aggravated by inhibitors. Two inhibitors also suppressed the total activities of the antioxidant enzymes superoxide dismutase (SOD, EC 1.15.1.1), catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11), and glutathione reductase (GR, EC 1.6.4.2). Besides, treatment with PQ stimulated the activation of a 46 kDa MAPK, which was identified as ZmMPK5 by in-gel kinase assay with immunoprecipitation. These results reveal that ABA-induced protection against PQ-generated oxidative damage is mediated through MAPK cascade in maize leaves, in which ZmMPK5, a candidate for MAPK, is demonstrated to be involved.

  17. Comparison of gene expression of mitogenic kinin path in adherent and non-adherent CD 34-stem cells using oligonucleotide microarrays.

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    Krzysztof Machaj

    2008-02-01

    Full Text Available One of the more interesting cells present in the umbilical cord blood - as far as their potential clinical use is concerned - are stem cells not presenting the CD34 antigen. These are the pluripotential cells with their biological properties similar to mesenchymal stem cells, with the ability to differentiate into such tissue types as bone, cartilage, nervous (to some extent, glia and muscle. The authors compared the activity of genes coding the proteins in mitogenic signal paths activated by kinin receptors using oligonucleotide microarrays in adherent and non-adherent CD 34- cells derived from umbilical cord blood. In the linear regression model with a 95% prognosis area for differentiating genes outside this area, the following genes were selected: c-jun (present in 3 isoforms and c-fos. The fos and jun genes create the AP-1 transcriptive factor which regulates the expression of genes taking part in numerous cellular processes, including the cell cycle and mitosis. The obtained results shed some light on the molecular processes behind the MSC proliferation and are a starting point for further studies on the mesenchymal stem cell biology.

  18. Key signalling nodes in mammary gland development and cancer. Mitogen-activated protein kinase signalling in experimental models of breast cancer progression and in mammary gland development.

    Science.gov (United States)

    Whyte, Jacqueline; Bergin, Orla; Bianchi, Alessandro; McNally, Sara; Martin, Finian

    2009-01-01

    Seven classes of mitogen-activated protein kinase (MAPK) intracellular signalling cascades exist, four of which are implicated in breast disease and function in mammary epithelial cells. These are the extracellular regulated kinase (ERK)1/2 pathway, the ERK5 pathway, the p38 pathway and the c-Jun N-terminal kinase (JNK) pathway. In some forms of human breast cancer and in many experimental models of breast cancer progression, signalling through the ERK1/2 pathway, in particular, has been implicated as being important. We review the influence of ERK1/2 activity on the organised three-dimensional association of mammary epithelial cells, and in models of breast cancer cell invasion. We assess the importance of epidermal growth factor receptor family signalling through ERK1/2 in models of breast cancer progression and the influence of ERK1/2 on its substrate, the oestrogen receptor, in this context. In parallel, we consider the importance of these MAPK-centred signalling cascades during the cycle of mammary gland development. Although less extensively studied, we highlight the instances of signalling through the p38, JNK and ERK5 pathways involved in breast cancer progression and mammary gland development.

  19. Ibuprofen abates cypermethrin-induced expression of pro-inflammatory mediators and mitogen-activated protein kinases and averts the nigrostriatal dopaminergic neurodegeneration.

    Science.gov (United States)

    Singh, Ashish; Tripathi, Pratibha; Prakash, Om; Singh, Mahendra Pratap

    2016-12-01

    Cypermethrin induces oxidative stress, microglial activation, inflammation and apoptosis leading to Parkinsonism in rats. While ibuprofen, a non-steroidal anti-inflammatory drug, relieves from inflammation, its efficacy against cypermethrin-induced Parkinsonism has not yet been investigated. The study aimed to explore the protective role of ibuprofen in cypermethrin-induced Parkinsonism, an environmentally relevant model of Parkinson's disease (PD), along with its underlying mechanism. Animals were treated with/without cypermethrin in the presence/absence of ibuprofen. Behavioural, immunohistochemical and biochemical parameters of Parkinsonism and expression of pro-inflammatory and pro-apoptotic proteins along with mitogen-activated protein kinases (MAPKs) were determined. Ibuprofen resisted cypermethrin-induced behavioural impairments, striatal dopamine depletion, oxidative stress in the nigrostriatal tissues and loss of the nigral dopamine producing cells and increase in microglial activation along with atypical expression of pro-inflammatory and apoptotic proteins that include cyclooxygenase-2, tumour necrosis factor-α, MAPKs (c-Jun N-terminal kinase, p38 and extracellular signal-regulated kinase), B cell lymphoma 2-associated protein X, tumour suppressor protein p53, cytochrome c and caspase-3 in the nigrostriatal tissue. The results obtained thus demonstrate that ibuprofen lessens inflammation and regulates MAPKs expression thereby averts cypermethrin-induced Parkinsonism.

  20. Effect of cyclic hydrodynamic pressure-induced proliferation of human bladder smooth muscle through Ras-related C3 botulinum toxin substrate 1, mitogen-activated protein kinase kinase 1/2 and extracellular regulated protein kinases 1/2.

    Science.gov (United States)

    Wu, Tao; Chen, Lin; Wei, Tangqiang; Wang, Yan; Xu, Feng; Wang, Kunjie

    2012-09-01

    To examine the role of Ras-related C3 botulinum toxin substrate 1, mitogen-activated protein kinase kinase 1/2 and extracellular regulated protein kinases 1/2 in the cyclic hydrodynamic pressure-induced proliferation of human bladder smooth muscle cells. Human bladder smooth muscle cells were exposed to cyclic hydrodynamic pressures in vitro with defined parameters (static, 100 cmH(2) O, 200 cmH(2) O and 300 cmH(2) O pressure) for 24 h. The proliferation of cells was assessed by flow cytometry. Ras-related C3 botulinum toxin substrate 1, mitogen-activated protein kinase kinase 1/2 and extracellular regulated protein kinases 1/2 messenger ribonucleic acid, and protein expression was analyzed by real-time polymerase chain reaction and Western blot. Specificity of the Rac1 was determined with real-time polymerase chain reaction and Western blot technique with small interfering ribonucleic acid transfection and Rac1 inhibitor (NSC23766). The proliferation of human bladder smooth muscle cells was increased. Ras-related C3 botulinum toxin substrate 1, mitogen-activated protein kinase kinase 1/2 and extracellular regulated protein kinases 1/2 were activated by 200 and 300 cmH(2) O cyclic hydrodynamic pressure compared with static and 100 cmH(2) O pressure. The "knockdown" of activation of Rac1 using target small interfering ribonucleic acid transfection and Rac1 inhibitor (NSC23766) decreased proliferation of human bladder smooth muscle cells, and downregulated mitogen-activated protein kinase kinase 1/2, extracellular regulated protein kinases 1/2. The Rac1 pathway is activated in mechanotransduction and regulation of human bladder smooth muscle cell proliferation in response to cyclic hydrodynamic pressure. © 2012 The Japanese Urological Association.

  1. Regulation of brain capillary endothelial cells by P2Y receptors coupled to Ca2+, phospholipase C and mitogen-activated protein kinase.

    Science.gov (United States)

    Albert, J L; Boyle, J P; Roberts, J A; Challiss, R A; Gubby, S E; Boarder, M R

    1997-11-01

    1. The blood-brain barrier is formed by capillary endothelial cells and is regulated by cell-surface receptors, such as the G protein-coupled P2Y receptors for nucleotides. Here we investigated some of the characteristics of control of brain endothelial cells by these receptors, characterizing the phospholipase C and Ca2+ response and investigating the possible involvement of mitogen-activated protein kinases (MAPK). 2. Using an unpassaged primary culture of rat brain capillary endothelial cells we showed that ATP, UTP and 2-methylthio ATP (2MeSATP) give similar and substantial increases in cytosolic Ca2+, with a rapid rise to peak followed by a slower decline towards basal or to a sustained plateau. Removal of extracellular Ca2+ had little effect on the peak Ca2+-response, but resulted in a more rapid decline to basal. There was no response to alpha,beta-MethylATP (alpha,beta MeATP) in these unpassaged cells, but a response to this P2X agonist was seen after a single passage. 3. ATP (log EC50 -5.1+/-0.2) also caused an increase in the total [3H]-inositol (poly)phosphates ([3H]-InsPx) in the presence of lithium with a rank order of agonist potency of ATP=UTP=UDP>ADP, with 2MeSATP and alpha,beta MeATP giving no detectable response. 4. Stimulating the cells with ATP or UTP gave a rapid rise in the level of inositol 1,4,5-trisphosphate (Ins(1,4,5)P3), with a peak at 10 s followed by a decline to a sustained plateau phase. 2MeSATP gave no detectable increase in the level of Ins(1,4,5)P3. 5. None of the nucleotides tested affected basal cyclic AMP, while ATP and ATPgammaS, but not 2MeSATP, stimulated cyclic AMP levels in the presence of 5 microM forskolin. 6. Both UTP and ATP stimulated tyrosine phosphorylation of p42 and p44 mitogen-activated protein kinase (MAPK), while 2MeSATP gave a smaller increase in this index of MAPK activation. By use of a peptide kinase assay, UTP gave a substantial increase in MAPK activity with a concentration-dependency consistent with

  2. The p38 mitogen activated protein kinase regulates β-amyloid protein internalization through the α7 nicotinic acetylcholine receptor in mouse brain.

    Science.gov (United States)

    Ma, Kai-Ge; Lv, Jia; Yang, Wei-Na; Chang, Ke-Wei; Hu, Xiao-Dan; Shi, Li-Li; Zhai, Wan-Ying; Zong, Hang-Fan; Qian, Yi-Hua

    2018-03-01

    Alzheimer's disease (AD) is one of the most devastating neurodegenerative disorders. Intracellular β-amyloid protein (Aβ) is an early event in AD. It induces the formation of amyloid plaques and neuron damage. The α7 nicotinic acetylcholine receptor (α7nAChR) has been suggested to play an important role in Aβ caused cognition. It has high affinity with Aβ and could mediate Aβ internalization in vitro. However, whether in mouse brain the p38 MAPK signaling pathway is involved in the regulation of the α7nAChR mediated Aβ internalization and their role in mitochondria remains little known. Therefore, in this study, we revealed that Aβ is internalized by cholinergic and GABAergic neurons. The internalized Aβ were found deposits in lysosomes/endosomes and mitochondria. Aβ could form Aβ-α7nAChR complex with α7nAChR, activates the p38 mitogen activated protein kinase (MAPK). And the increasing of α7nAChR could in return mediate Aβ internalization in the cortex and hippocampus. In addition, by using the α7nAChR agonist PNU282987, the p38 phosphorylation level decreases, rescues the biochemical changes which are tightly associated with Aβ-induced apoptosis, such as Bcl2/Bax level, cytochrome c (Cyt c) release. Collectively, the p38 MAPK signaling pathway could regulate the α7nAChR-mediated internalization of Aβ. The activation of α7nAChR or the inhibition of p38 MAPK signaling pathway may be a beneficial therapy to AD. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Genome-Wide Survey and Expression Profile Analysis of the Mitogen-Activated Protein Kinase (MAPK) Gene Family in Brassica rapa.

    Science.gov (United States)

    Lu, Kun; Guo, Wenjin; Lu, Junxing; Yu, Hao; Qu, Cunmin; Tang, Zhanglin; Li, Jiana; Chai, Yourong; Liang, Ying

    2015-01-01

    Mitogen-activated protein kinase (MAPK) cascades are fundamental signal transduction modules in plants, controlling cell division, development, hormone signaling, and biotic and abiotic stress responses. Although MAPKs have been investigated in several plant species, a comprehensive analysis of the MAPK gene family has hitherto not been performed in Brassica rapa. In this study, we identified 32 MAPKs in the B. rapa genome by conducting BLASTP and syntenic block analyses, and screening for the essential signature motif (TDY or TEY) of plant MAPK proteins. Of the 32 BraMAPK genes retrieved from the Brassica Database, 13 exhibited exon splicing errors, excessive splicing of the 5' sequence, excessive retention of the 5' sequence, and sequencing errors of the 3' end. Phylogenetic trees of the 32 corrected MAPKs from B. rapa and of MAPKs from other plants generated by the neighbor-joining and maximum likelihood methods suggested that BraMAPKs could be divided into four groups (groups A, B, C, and D). Gene number expansion was observed for BraMAPK genes in groups A and D, which may have been caused by the tandem duplication and genome triplication of the ancestral genome of the Brassica progenitor. Except for five members of the BraMAPK10 subfamily, the identified BraMAPKs were expressed in most of the tissues examined, including callus, root, stem, leaf, flower, and silique. Quantitative real-time PCR demonstrated that at least six and five BraMAPKs were induced or repressed by various abiotic stresses and hormone treatments, respectively, suggesting their potential roles in the abiotic stress response and various hormone signal transduction pathways in B. rapa. This study provides valuable insight into the putative physiological and biochemical functions of MAPK genes in B. rapa.

  4. BIRB796, the inhibitor of p38 mitogen-activated protein kinase, enhances the efficacy of chemotherapeutic agents in ABCB1 overexpression cells.

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    Dan He

    Full Text Available ATP-binding-cassette family membrane proteins play an important role in multidrug resistance. In this study, we investigated BIRB796, an orally active inhibitor of p38 mitogen-activated protein kinase, reversed MDR induced by ABCB1, ABCG2 and ABCC1. Our results showed that BIRB796 could reverse ABCB1-mediated MDR in both the drug selected and transfected ABCB1-overexpressing cell models, but did not enhance the efficacy of substrate-chemotherapeutical agents in ABCC1 or ABCG2 overexpression cells and their parental sensitive cells. Furthermore, BIRB796 increased the intracellular accumulation of the ABCB1 substrates, such as rhodamine 123 and doxorubicin. Moreover, BIRB796 bidirectionally mediated the ATPase activity of ABCB1, stimulating at low concentration, inhibiting at high concentration. However, BIRB796 did not alter the expression of ABCB1 both at protein and mRNA level. The down-regulation of p38 by siRNA neither affected the expression of ABCB1 nor the cytotoxic effect of paclitaxel on KBV200. The binding model of BIRB796 within the large cavity of the transmembrane region of ABCB1 may form the basis for future lead optimization studies. Importantly, BIRB796 also enhanced the effect of paclitaxel on the inhibition of growth of the ABCB1-overexpressing KBV200 cell xenografts in nude mice. Overall, we conclude that BIRB796 reverses ABCB1-mediated MDR by directly inhibiting its transport function. These findings may be useful for cancer combinational therapy with BIRB796 in the clinic.

  5. P38 mitogen-activated protein kinase inhibitor, FR167653, inhibits parathyroid hormone related protein-induced osteoclastogenesis and bone resorption.

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    Huiren Tao

    Full Text Available p38 mitogen-activated protein kinase (MAPK acts downstream in the signaling pathway that includes receptor activator of NF-κB (RANK, a powerful inducer of osteoclast formation and activation. We investigated the role of p38 MAPK in parathyroid hormone related protein (PTHrP-induced osteoclastogenesis in vitro and PTHrP-induced bone resorption in vivo. The ability of FR167653 to inhibit osteoclast formation was evaluated by counting the number of tartrate-resistant acid phosphatase positive multinucleated cells (TRAP-positive MNCs in in vitro osteoclastgenesis assays. Its mechanisms were evaluated by detecting the expression level of c-Fos and nuclear factor of activated T cells c1 (NFATc1 in bone marrow macrophages (BMMs stimulated with sRANKL and M-CSF, and by detecting the expression level of osteoprotegerin (OPG and RANKL in bone marrow stromal cells stimulated with PTHrP in the presence of FR167653. The function of FR167653 on bone resorption was assessed by measuring the bone resorption area radiographically and by counting osteoclast number per unit bone tissue area in calvaria in a mouse model of bone resorption by injecting PTHrP subcutaneously onto calvaria. Whole blood ionized calcium levels were also recorded. FR167653 inhibited PTHrP-induced osteoclast formation and PTHrP-induced c-Fos and NFATc1 expression in bone marrow macrophages, but not the expression levels of RANKL and OPG in primary bone marrow stromal cells treated by PTHrP. Furthermore, bone resorption area and osteoclast number in vivo were significantly decreased by the treatment of FR167653. Systemic hypercalcemia was also partially inhibited. Inhibition of p38 MAPK by FR167653 blocks PTHrP-induced osteoclastogenesis in vitro and PTHrP-induced bone resorption in vivo, suggesting that the p38 MAPK signaling pathway plays a fundamental role in PTHrP-induced osteoclastic bone resorption.

  6. Effects of sustained sleep restriction on mitogen-stimulated cytokines, chemokines and T helper 1/ T helper 2 balance in humans.

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    John Axelsson

    Full Text Available BACKGROUND: Recent studies suggest that acute sleep deprivation disrupts cellular immune responses by shifting T helper (Th cell activity towards a Th2 cytokine profile. Since little is known about more long-term effects, we investigated how five days of sleep restriction would affect pro-inflammatory, chemotactic, Th1- and Th2 cytokine secretion. METHODS: Nine healthy males participated in an experimental sleep protocol with two baseline sleep-wake cycles (sleep 23.00-07.00 h followed by 5 days with restricted sleep (03.00-07.00 h. On the second baseline day and on the fifth day with restricted sleep, samples were drawn every third hour for determination of cytokines/chemokines (tumor necrosis factor alpha (TNF-α, interleukin (IL -1β, IL-2, IL-4 and monocyte chemoattractant protein-1 (MCP-1 after in vitro stimulation of whole blood samples with the mitogen phytohemagglutinin (PHA. Also leukocyte numbers, mononuclear cells and cortisol were analysed. RESULTS: 5-days of sleep restriction affected PHA-induced immune responses in several ways. There was a general decrease of IL-2 production (p<.05. A shift in Th1/Th2 cytokine balance was also evident, as determined by a decrease in IL2/IL4 ratio. No other main effects of restricted sleep were shown. Two significant interactions showed that restricted sleep resulted in increased TNF-α and MCP-1 in the late evening and early night hours (p's<.05. In addition, all variables varied across the 24 h day. CONCLUSIONS: 5-days of sleep restriction is characterized by a shift towards Th2 activity (i.e. lower 1L-2/IL-4 ratio which is similar to the effects of acute sleep deprivation and psychological stress. This may have implications for people suffering from conditions characterized by excessive Th2 activity like in allergic disease, such as asthma, for whom restricted sleep could have negative consequences.

  7. Decisive role of P42/44 mitogen-activated protein kinase in Δ9-tetrahydrocannabinol-induced migration of human mesenchymal stem cells.

    Science.gov (United States)

    Lüder, Ellen; Ramer, Robert; Peters, Kirsten; Hinz, Burkhard

    2017-12-01

    In past years, medical interest in Δ 9 -tetrahydrocannabinol (THC), the major psychoactive ingredient of the Cannabis plant, has been renewed due to the elucidation of the endocannabinoid system and diverse other receptor targets involved in biological cannabinoid effects. The present study therefore investigates the impact of THC on the migration of mesenchymal stem cells (MSCs) which are known to be involved in various regenerative processes such as bone healing. Using Boyden chamber assays, THC was found to increase the migration of adipose-derived MSCs. Migration by THC was almost completely suppressed by the CB 1 receptor antagonist AM-251 and to a lesser extent by the CB 2 receptor antagonist AM-630. By contrast, the TRPV1 antagonist capsazepine as well as the G protein-coupled receptor 55 (GRP55) agonist O-1602 did not significantly interfere with the promigratory effect of THC. Furthermore, increased migration by THC was fully suppressed by PD98059, an inhibitor of p42/44 mitogen-activated protein kinase (MAPK) activation, and was accompanied by a time-dependent activation of this pathway accordingly. In line with the migration data, additional inhibitor experiments pointed towards a decisive role of the CB 1 receptor in conferring THC-induced activation of p42/44 MAPK. Collectively, this study demonstrates THC to exert a promigratory effect on MSCs via a CB 1 receptor-dependent activation of p42/44 MAPK phosphorylation. This pathway may be involved in regenerative effects of THC and could be a target of pharmacological intervention.

  8. Mitogen activated protein kinase 6 and MAP kinase phosphatase 1 are involved in the response of Arabidopsis roots to L-glutamate.

    Science.gov (United States)

    López-Bucio, Jesús Salvador; Raya-González, Javier; Ravelo-Ortega, Gustavo; Ruiz-Herrera, León Francisco; Ramos-Vega, Maricela; León, Patricia; López-Bucio, José; Guevara-García, Ángel Arturo

    2018-03-01

    The function and components of L-glutamate signaling pathways in plants have just begun to be elucidated. Here, using a combination of genetic and biochemical strategies, we demonstrated that a MAPK module is involved in the control of root developmental responses to this amino acid. Root system architecture plays an essential role in plant adaptation to biotic and abiotic factors via adjusting signal transduction and gene expression. L-Glutamate (L-Glu), an amino acid with neurotransmitter functions in animals, inhibits root growth, but the underlying genetic mechanisms are poorly understood. Through a combination of genetic analysis, in-gel kinase assays, detailed cell elongation and division measurements and confocal analysis of expression of auxin, quiescent center and stem cell niche related genes, the critical roles of L-Glu in primary root growth acting through the mitogen-activated protein kinase 6 (MPK6) and the dual specificity serine-threonine-tyrosine phosphatase MKP1 could be revealed. In-gel phosphorylation assays revealed a rapid and dose-dependent induction of MPK6 and MPK3 activities in wild-type Arabidopsis seedlings in response to L-Glu. Mutations in MPK6 or MKP1 reduced or increased root cell division and elongation in response to L-Glu, possibly modulating auxin transport and/or response, but in a PLETHORA1 and 2 independent manner. Our data highlight MPK6 and MKP1 as components of an L-Glu pathway linking the auxin response, and cell division for primary root growth.

  9. Mutations in the c-Kit Gene Disrupt Mitogen-Activated Protein Kinase Signaling during Tumor Development in Adenoid Cystic Carcinoma of the Salivary Glands

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    Osamu Tetsu

    2010-09-01

    Full Text Available The Ras/mitogen-activated protein kinase (MAPK pathway is considered to be a positive regulator of tumor initiation, progression, and maintenance. This study reports an opposite finding: we have found strong evidence that the MAPK pathway is inhibited in a subset of adenoid cystic carcinomas (ACCs of the salivary glands. ACC tumors consistently overexpress the receptor tyrosine kinase (RTK c-Kit, which has been considered a therapeutic target. We performed mutational analysis of the c-Kit gene (KIT in 17 cases of ACC and found that 2 cases of ACC had distinct missense mutations in KIT at both the genomic DNA and messenger RNA levels. These mutations caused G664R and R796G amino acid substitutions in the kinase domains. Surprisingly, the mutations were functionally inactive in cultured cells. We observed a significant reduction of MAPK (ERK1/2 activity in tumor cells, as assessed by immunohistochemistry. We performed further mutational analysis of the downstream effectors in the c-Kit pathway in the genes HRAS, KRAS, NRAS, BRAF, PIK3CA, and PTEN. This analysis revealed that two ACC tumors without KIT mutations had missense mutations in either KRAS or BRAF, causing S17N K-Ras and V590I B-Raf mutants, respectively. Our functional analysis showed that proteins with these mutations were also inactive in cultured cells. This is the first time that MAPK activity from the RTK signaling has been shown to be inhibited by gene mutations during tumor development. Because ACC seems to proliferate despite inactivation of the c-Kit signaling pathway, we suggest that selective inhibition of c-Kit is probably not a suitable treatment strategy for ACC.

  10. Skeletal muscle mitogen-activated protein kinases and ribosomal S6 kinases. Suppression in chronic diabetic rats and reversal by vanadium.

    Science.gov (United States)

    Hei, Y J; Chen, X; Pelech, S L; Diamond, J; McNeill, J H

    1995-10-01

    The mitogen-activated protein (MAP) kinases and ribosomal S6 protein kinases in the skeletal muscle of insulin-resistant long-term (2 and 6 months' duration) diabetic rats were investigated to understand further the changes in insulin intracellular signaling pathways that accompany diabetes. The effects of insulin-mimetic vanadium compounds on the activity of these kinases were also examined. In the insulin-resistant 2-month diabetic rats, the basal activities of MAP kinases were relatively unchanged, while the basal activities of S6 kinases were significantly increased. Intravenous injection of insulin moderately activated both the 42-kDa MAP kinase (p42mapk) and a 44-kDa MAP kinase (p44erk1) in the 2-month control rats but not in the 2-month diabetic rats. Insulin treatment markedly stimulated the activity of a novel 31-kDa S6 kinase and the previously described 90-kDa ribosomal S6 kinase encoded by one of the rsk genes (p90rsk) in the 2-month control rats, while the effect was substantially reduced in the diabetic rats. In the 6-month diabetic rats, the basal phosphotransferase activities of both MAP kinases were depressed threefold or greater. This correlated with reductions in the amount of immunoreactive p42mapk and p44erk1 proteins in extracts from the diabetic rats. The basal activity of the 31-kDa S6 kinase activity was also reduced fourfold in the 6-month diabetic rats. Treatment of the 2-month diabetic rats with vanadyl sulfate resulted in euglycemia, prevented the increase in the basal activity of S6 kinase, and improved the activation of S6 kinase by insulin.(ABSTRACT TRUNCATED AT 250 WORDS)

  11. Polyclonal activation of rat B cells. I. A single mitogenic signal can stimulate proliferation, but three signals are required for differentiation

    International Nuclear Information System (INIS)

    Stunz, L.L.; Feldbush, T.L.

    1986-01-01

    A water-soluble, proteinaceous preparation derived from the cell walls of Salmonella typhimurium Re mutants has recently been tested in this laboratory for its ability to act as a mitogen for rat lymphocytes. This preparation (STM) has been found to be a potent simulator of B lymphocyte proliferation, as measured both by 3 H-TdR incorporation and by cell cycle analysis performed with flow cytofluorometry. STM stimulates approximately 50% of rat B cells to enter cycle. Previous investigations by others have shown that at least two sets of signals are required for B cell differentiation; (a) proliferation signals that may consist of both a stimulator of B cell conversion from G 0 to G 1 and growth factors, and (b) differentiation signals that probably include at least two B cell differentiation factors (BCDF). When STM was tested in a differentiation system it did not drive purified B cells to differentiate to PFC, either alone or when supplemented with a supernatant from concanavalin A-stimulated spleen cells (CAS). However, when both CAS and dextran sulfate (DXS) were supplied to the STM-stimulated cells, a large number of PFC resulted. DXT does not act by stimulating an additional, CAS-responsive B cell subset, since it has only a marginal effect upon 3 H-TdR uptake and does not increase the number of B cells in cycle when used together with STM. The authors that the two agents may be acting sequentially: STM stimulates the B cells to proliferate, and DXS drives the proliferating cells to become responsive to CAS. This suggests that the signals for B cell differentiation must consist of at least three activities: a trigger to stimulate the cells to proliferate, a factor to drive the cells to a BCDF-responsive state, and a BCDF that can drive the cells to secrete antibody

  12. Both mitogen activated protein kinase and the mammalian target of rapamycin modulate the development of functional renal proximal tubules in matrigel.

    Science.gov (United States)

    Han, Ho Jae; Sigurdson, Wade J; Nickerson, Peter A; Taub, Mary

    2004-04-01

    Tubules may arise during branching morphogenesis through several mechanisms including wrapping, budding, cavitation and cord hollowing. In this report we present evidence that is consistent with renal proximal tubule formation through a process of cord hollowing (a process that requires the concomitant establishment of apicobasal polarity and lumen formation). Pockets of lumen filled with Lucifer Yellow were observed within developing cords of rabbit renal proximal tubule cells in matrigel. The observation of Lucifer Yellow accumulation suggests functional polarization. In the renal proximal tubule Lucifer Yellow is initially transported intracellularly by means of a basolaterally oriented p-aminohippurate transport system, followed by apical secretion into the lumen of the nephron. Consistent with such polarization in developing tubules, Triticum vulgare was observed to bind to the lumenal membranes within pockets of Lucifer Yellow-filled lumens. As this lectin binds apically in the rabbit renal proximal tubule, T. vulgare binding is indicative of the emergence of an apical domain before the formation of a contiguous lumen. Both epidermal growth factor and hepatocyte growth factor stimulated the formation of transporting tubules. The stimulatory effect of both epidermal growth factor and hepatocyte growth factor on tubulogenesis was inhibited by PD98059, a mitogen activated protein kinase kinase inhibitor, rather than by wortmannin, an inhibitor of phosphoinositide 3-kinase. Nevertheless, Lucifer Yellow-filled lumens were observed in tubules that formed in the presence of PD98059 as well as with wortmannin, indicating that these drugs did not prevent the process of cavitation. By contrast, rapamycin, an inhibitor of the mammalian target of rapamycin, prevented the process of cavitation without affecting the frequency of formation of developing cords. Multicellular cysts were observed to form in 8-bromocyclic AMP-treated cultures. As these cysts did not similarly

  13. Arabidopsis Raf-Like Mitogen-Activated Protein Kinase Kinase Kinase Gene Raf43 Is Required for Tolerance to Multiple Abiotic Stresses.

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    Nasar Virk

    Full Text Available Mitogen-activated protein kinase (MAPK cascades are critical signaling modules that mediate the transduction of extracellular stimuli into intracellular response. A relatively large number of MAPKKKs have been identified in a variety of plant genomes but only a few of them have been studied for their biological function. In the present study, we identified an Arabidopsis Raf-like MAPKKK gene Raf43 and studied its function in biotic and abiotic stress response using a T-DNA insertion mutant raf43-1 and two Raf43-overexpressing lines Raf43-OE#1 and Raf43-OE#13. Expression of Raf43 was induced by multiple abiotic and biotic stresses including treatments with drought, mannitol and oxidative stress or defense signaling molecule salicylic acid and infection with necrotrophic fungal pathogen Botrytis cinerea. Seed germination and seedling root growth of raf43-1 were significantly inhibited on MS medium containing mannitol, NaCl, H2O2 or methyl viologen (MV while seed germination and seedling root growth of the Raf43-OE#1 and Raf43-OE#13 lines was similar to wild type Col-0 under the above stress conditions. Soil-grown raf43-1 plants exhibited reduced tolerance to MV, drought and salt stress. Abscisic acid inhibited significantly seed germination and seedling root growth of the raf43-1 line but had no effect on the two Raf43-overexpressing lines. Expression of stress-responsive RD17 and DREB2A genes was significantly down-regulated in raf43-1 plants. However, the raf43-1 and Raf43-overexpressing plants showed similar disease phenotype to the wild type plants after infection with B. cinerea or Pseudomonas syringae pv. tomato DC3000. Our results demonstrate that Raf43, encoding for a Raf-like MAPKKK, is required for tolerance to multiple abiotic stresses in Arabidopsis.

  14. Electroacupuncture reduces apoptotic index and inhibits p38 mitogen-activated protein kinase signaling pathway in the hippocampus of rats with cerebral ischemia/reperfusion injury

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    Xiao Lan

    2017-01-01

    Full Text Available Electroacupuncture attenuates cerebral hypoxia and neuronal apoptosis induced by cerebral ischemia/reperfusion injury. To further identify the involved mechanisms, we assumed that electroacupuncture used to treat cerebral ischemia/reperfusion injury was associated with the p38 mitogen-activated protein kinase (MAPK signaling pathway. We established rat models of cerebral ischemia/reperfusion injury using the modified Zea-Longa's method. At 30 minutes before model establishment, p38 MAPK blocker SB20358 was injected into the left lateral ventricles. At 1.5 hours after model establishment, electroacupuncture was administered at acupoints of Chize (LU5, Hegu (LI4, Zusanli (ST36, and Sanyinjiao (SP6 for 20 minutes in the affected side. Results showed that the combination of EA and SB20358 injection significantly decreased neurologic impairment scores, but no significant differences were determined among different interventional groups. Hematoxylin-eosin staining also showed reduced brain tissue injuries. Compared with the SB20358 group, the cells were regularly arranged, the structures were complete, and the number of viable neurons was higher in the SB20358 + electroacupuncture group. Terminal deoxynucleotidyl transferase (TdT-mediated dUTP nick-end labeling assay showed a decreased apoptotic index in each group, with a significant decrease in the SB20358 + electroacupuncture group. Immunohistochemistry revealed reduced phosphorylated p38 expression at 3 days in the electroacupuncture group and SB20358 + electroacupuncture group compared with the ischemia/reperfusion group. There was no significant difference in phosphorylated p38 expression between the ischemia/reperfusion group and SB20358 group. These findings confirmed that the electroacupuncture effects on mitigating cerebral ischemia/reperfusion injury are possibly associated with the p38 MAPK signaling pathway. A time period of 3 days could promote the repair of ischemic cerebral nerves.

  15. Colletotrichum higginsianum Mitogen-Activated Protein Kinase ChMK1: Role in Growth, Cell Wall Integrity, Colony Melanization and Pathogenicity

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    Wei Wei

    2016-08-01

    Full Text Available Colletotrichum higginsianum is an economically important pathogen that causes anthracnose disease in a wide range of cruciferous crops. To facilitate the efficient control of anthracnose disease, it will be important to understand the mechanism by which the cruciferous crops and C. higginsianum interact. A key step in understanding this interaction is characterizing the mitogen-activated protein kinases (MAPK signaling pathway of C. higginsianum. MAPK plays important roles in diverse physiological processes of multiple pathogens. In this study, a Fus3/Kss1-related MAPK gene, ChMK1, from C. higginsianum was analyzed. The results showed that the Fus3/Kss1-related MAPK ChMK1 plays a significant role in cell wall integrity. Targeted deletion of ChMK1 resulted in a hypersensitivity to cell wall inhibitors, reduced conidiation and albinistic colonies. Further, the deletion mutant was also unable to form melanized appressorium, a specialized infection structure that is necessary for successful infection. Therefore, the deletion mutant loses pathogenicity on A. thaliana leaves, demonstrating that ChMK1 plays an essential role in the early infection step. In addition, the ChMK1 deletion mutant showed an attenuated growth rate that is different from that of its homologue in C. lagenarium, indicating the diverse roles that Fus3/Kss1-related MAPKs plays in phytopathogenic fungi. Furthermore, the expression level of three melanin synthesis associated genes were clearly decreased in the albinistic ChMK1 mutant compared to that of the wild type strain, suggesting that ChMK1 is also required for colony melanization in C. higginsianum.

  16. Upstream and Downstream Co-inhibition of Mitogen-Activated Protein Kinase and PI3K/Akt/mTOR Pathways in Pancreatic Ductal Adenocarcinoma

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    Matthew H. Wong

    2016-07-01

    Full Text Available BACKGROUND: Extensive cross talk exists between PI3K/Akt/mTOR and mitogen-activated protein kinase (MAPK pathways, and both are upregulated in pancreatic ductal adenocarcinoma (PDAC. Our previous study suggested that epidermal growth factor receptor inhibitor erlotinib which acts upstream of these pathways acts synergistically with PI3K inhibitors in PDAC. Horizontal combined blockade upstream and downstream of these two pathways is therefore explored. METHODS: Erlotinib paired with PI3K inhibitor (BYL719 was tested against erlotinib plus dual PI3K/mTOR inhibitor BEZ-235, and MEK inhibitor (PD98059 plus BEZ235, on five primary PDAC cell lines and on two pairs of parent and erlotinib-resistant (ER cell lines. A range of in vitro assays including cell proliferation, Western blotting, migration, clonogenic, cell cycle, and apopotic assays was used to test for the efficacy of combined blockade. RESULTS: Dual downstream blockade of the MAPK and PAM pathways was more effective in attenuating downstream molecular signals. Synergy was demonstrated for erlotinib and BEZ235 and for PD-98059 and BEZ-235. This resulted in a trend of increased growth cell cycle arrest, apoptosis, cell proliferation, and colony and migration suppression. This combination showed more efficacy in cell lines with acquired resistance to erlotinib. CONCLUSIONS: The additional mTOR blockade provided by BEZ235 in combined blockade resulted in increased anticancer effect. The hypersensitivity of ER cell lines to additional mTOR blockade suggested PAM pathway oncogenic dependence via mTOR. Dual downstream combined blockade of MAPK and PAM pathways with MEK and PI3K/mTOR inhibitor appeared most effective and represents an attractive therapeutic strategy against pancreatic cancer and its associated drug resistance.

  17. Crosstalk between Smad and Mitogen-Activated Protein Kinases for the Regulation of Apoptosis in Cyclosporine A- Induced Renal Tubular Injury

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    Hideyuki Iwayama

    2011-10-01

    Full Text Available Background/Aims: It remains elusive whether there is a crosstalk between Smad and mitogen-activated protein kinases (MAPKs and whether it regulates cyclosporine A (CyA-induced apoptosis in renal proximal tubular cells (RPTCs. Methods: The effect of CyA on nuclear translocation of Smad2/3 and MAPKs (measured by Western blotting or immunofluorescence and apoptosis (determined by Hoechst 33258 staining was examined in HK-2 cells. Results: CyA induced apoptosis at 24 h and nuclear translocation of phosphorylated (p-Smad2/3 at 3 h, which was continued till 24 h. CyA enhanced the expression of p-ERK at 1 h, which was continued till 24 h, and of p-p38MAPK at 1–6 h, which returned to control level at 12 h. CyA did not affect JNK. An inhibitor of ERK, PD98059, prevented CyA-induced nuclear translocation of Smad2/3 and apoptosis. An inhibitor of p38MAPK, SB202190, deteriorated CyA-induced nuclear translocation of p-Smad2/3. Epidermal growth factor (EGF activated ERK and p38MAPK but not JNK. EGF-induced activation of MAPKs ameliorated CyA-induced nuclear translocation of p-Smad2/3 and apoptosis. Inhibition of p38MAPK but not of ERK abolished the protective effect of EGF on CyA-induced nuclear translocation of p-Smad2/3 and apoptosis. Conclusion: Crosstalk between R-Smad and p38MAPK/ERK, but not JNK differentially regulates apoptosis in CyA-induced RPTC injury.

  18. Aloin promotes A549 cell apoptosis via the reactive oxygen species‑mitogen activated protein kinase signaling pathway and p53 phosphorylation.

    Science.gov (United States)

    Wan, Li; Zhang, Lin; Fan, Kai; Wang, Jianjun

    2017-11-01

    Aloin has the potential to be a novel anticancer agent in cancer therapies. However, the detailed anticancer effect of Aloin remains to be fully elucidated. The present study analyzed the p53‑dependent mechanisms in response to Aloin treatment. Using the p53‑proficient A549 cells, an Aloin‑induced apoptotic cell model was established, which was used to evaluate the potential underlying molecular mechanisms. The results demonstrated that 200, 300 and 400 µM Aloin induced intrinsic cell apoptosis, which was further confirmed by disruption of the mitochondrial membrane potential, elevation of cytosolic Ca2+ levels, and activation of B‑cell lymphoma 2 (Bcl‑2) homologous antagonist killer, Bcl‑2 X‑associated protein, p53 upregulated modulator of apoptosis and phorbol‑12‑myristate‑13‑acetate‑induced protein 1. Aloin‑induced apoptosis was also accompanied by the induction of p53 phosphorylation on Serine (Ser)15, Threonine 18, Ser20 and Ser392; however, there were no significant differences in the expression of p53 and mouse double minute 2 homolog. Aloin‑induced apoptosis was reactive oxygen species (ROS)‑ and c‑Jun/p38‑dependent, as specific inhibitors for ROS, phosphorylated (p)‑c‑Jun and p‑p38 may attenuate Aloin‑induced A549 cell proliferating inhibition. In conclusion, these results suggested that Aloin may induce apoptosis in A549 cells via the ROS‑mitogen activated protein kinase signaling pathway, with p53 phosphorylation. These results implicate Aloin as a potential therapeutic agent for the treatment of lung cancer.

  19. Xingshentongqiao Decoction Mediates Proliferation, Apoptosis, Orexin-A Receptor and Orexin-B Receptor Messenger Ribonucleic Acid Expression and Represses Mitogen-activated Protein Kinase Signaling

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    Yuanli Dong

    2015-01-01

    Full Text Available Background: Hypocretin (HCRT signaling plays an important role in the pathogenesis of narcolepsy and can be significantly influenced by Chinese herbal therapy. Our previous study showed that xingshentongqiao decoction (XSTQ is clinically effective for the treatment of narcolepsy. To determine whether XSTQ improves narcolepsy by modulating HCRT signaling, we investigated its effects on SH-SY5Y cell proliferation, apoptosis, and HCRT receptor 1/2 (orexin receptor 1 [OX1R] and orexin receptor 2 [OX2R] expression. The signaling pathways involved in these processes were also assessed. Methods: The effects of XSTQ on proliferation and apoptosis in SH-SY5Y cells were assessed using cell counting kit-8 and annexin V-fluorescein isothiocyanate assays. OX1R and OX2R expression was assessed by quantitative real-time polymerase chain reaction analysis. Western blotting for mitogen-activated protein kinase (MAPK pathway activation was performed to further assess the signaling mechanism of XSTQ. Results: XSTQ reduced the proliferation and induced apoptosis of SH-SY5Y cells. This effect was accompanied by the upregulation of OX1R and OX2R expression and the reduced phosphorylation of extracellular signal-regulated kinase (Erk 1/2, p38 MAPK and c-Jun N-terminal kinase (JNK. Conclusions: XSTQ inhibits proliferation and induces apoptosis in SH-SY5Y cells. XSTQ also promotes OX1R and OX2R expression. These effects are associated with the repression of the Erk1/2, p38 MAPK, and JNK signaling pathways. These results define a molecular mechanism for XSTQ in regulating HCRT and MAPK activation, which may explain its ability to treat narcolepsy.

  20. Mitogen-inducible gene-6 partly mediates the inhibitory effects of prenatal dexamethasone exposure on endochondral ossification in long bones of fetal rats.

    Science.gov (United States)

    Zhang, Xianrong; Shang-Guan, Yangfan; Ma, Jing; Hu, Hang; Wang, Linlong; Magdalou, Jacques; Chen, Liaobin; Wang, Hui

    2016-07-01

    Prenatal exposure to dexamethasone slows down fetal linear growth and bone mineralization but the regulatory mechanism remains unknown. Here we assessed how dexamethasone regulates bone development in the fetus. Dexamethasone (1 mg·kg(-1) ·day(-1) ) was injected subcutaneously every morning in pregnant rats from gestational day (GD)9 to GD20. Fetal femurs and tibias were harvested at GD20 for histological and gene expression analysis. Femurs of 12-week-old female offspring were harvested for microCT (μCT) measurement. Primary chondrocytes were treated with dexamethasone (10, 50, 250 and 1000 nM). Prenatal dexamethasone exposure resulted in accumulation of hypertrophic chondrocytes and delayed formation of the primary ossification centre in fetal long bone. The retardation was accompanied by reduced maturation of hypertrophic chondrocytes, decreased osteoclast number and down-regulated expression of osteocalcin and bone sialoprotein in long bone. In addition, the mitogen-inducible gene-6 (Mig6) and osteoprotegerin (OPG) expression were stimulated, and the receptor activator of NF-κB ligand (RANKL) expression was repressed. Moreover, dexamethasone activated OPG and repressed RANKL expression in both primary chondrocytes and primary osteoblasts, and the knockdown of Mig6 abolished the effect of dexamethasone on OPG expression. Further, μCT measurement showed loss of bone mass in femur of 12-week-old offspring with prenatal dexamethasone exposure. Prenatal dexamethasone exposure delays endochondral ossification by suppressing chondrocyte maturation and osteoclast differentiation, which may be partly mediated by Mig6 activation in bone. Bone development retardation in the fetus may be associated with reduced bone mass in later life. © 2016 The British Pharmacological Society.

  1. Inhibition of mitogen activated protein kinases increases the sensitivity of A549 lung cancer cells to the cytotoxicity induced by a kava chalcone analog.

    Science.gov (United States)

    Warmka, Janel K; Solberg, Eric L; Zeliadt, Nicholette A; Srinivasan, Balasubramanian; Charlson, Aaron T; Xing, Chengguo; Wattenberg, Elizabeth V

    2012-08-03

    We are interested in investigating the biological activity of chalcones, a major class of compounds found in the beverage kava, in order to develop potent and selective chemopreventive candidates. Consumption of kava in the South Pacific Islands is inversely correlated with cancer incidence, even among smokers. Accordingly, chalcones have anti-cancer activities in animal and cell culture models. To investigate signaling pathways that affect chalcone action we studied a potent analog, (E)-3-(3-hydroxy-4-methoxyphenyl)-1-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (chalcone-24). Chalcone-24 was selected from a series of chalcone analogs that were synthesized based on the structures derived from flavokawain compounds found in kava, and screened in A549 lung cancer cells for induction of cytotoxicity and inhibition of NF-κB, a transcription factor associated with cell survival. Incubation of A549 cells with chalcone-24 resulted in a dose-dependent inhibition of cell viability, inhibition of NF-κB, activation of caspases, and activation of extracellular signal regulated kinase 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK); ERK1/2 and JNK are mitogen activated protein kinases that play central roles in regulating cell fate. Pharmacological inhibitors of ERK1/2 or JNK increased the sensitivity of A549 cells to chalcone-24-induced cytotoxicity, without affecting NF-κB or caspase activity. These results will help refine the synthesis of chalcone analogs to maximize the combination of actions required to prevent and treat cancer. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. BRAF mutations and phosphorylation status of mitogen-activated protein kinases in the development of flat and depressed-type colorectal neoplasias

    Science.gov (United States)

    Konishi, K; Takimoto, M; Kaneko, K; Makino, R; Hirayama, Y; Nozawa, H; Kurahashi, T; Kumekawa, Y; Yamamoto, T; Ito, H; Yoshikawa, N; Kusano, M; Nakayama, K; Rembacken, B J; Ota, H; Imawari, M

    2006-01-01

    Although some molecular differences between flat-depressed neoplasias (FDNs) and protruding neoplasias (PNs) have been reported, it is uncertain if the BRAF mutations or the status of phosphorylated mitogen-activated protein kinase (p-MAPK) are different between theses two groups. We evaluated the incidence of BRAF and KRAS mutations, high-frequency microsatellite instability (MSI-H), and the immunohistochemical status of p-MAPK in the nonserrated neoplasias (46 FDNs and 57 PNs). BRAF mutations were detected in four FDNs (9%) and none of PNs (P=0.0369 by Fisher's exact test). KRAS mutations were observed in none of FDNs and in 14 PNs (25%; P=0.0002 by Fisher's exact test). MSI-H was detected in seven out of 44 FDNs (16%) and in one out of 52 of PNs (2%) (P=0.022 by Fisher's exact test). Type B and C immunostaining for p-MAPK was observed in 34 out of 46 FDNs (72%), compared with 24 out of 55 PNs (44%; P=0.0022 by χ2 test). There was no significant difference in the type B and C immunostaining of p-MAPK between FDNs with and without BRAF mutations. BRAF and KRAS mutations are mutually exclusive in the morphological characteristics of colorectal nonserrated neoplasia. Abnormal accumulation of p-MAPK protein is more likely to be implicated in the tumorigenesis of FDNs than of PNs. However, this abnormality in FDNs might occur via the genetic alteration other than BRAF or KRAS mutation. PMID:16404419

  3. Stimulated initiation of mitogen-activated protein kinase phosphatase-1 (MKP-1) gene transcription involves the synergistic action of multiple cis-acting elements in the proximal promoter.

    Science.gov (United States)

    Ryser, Stephan; Massiha, Abbas; Piuz, Isabelle; Schlegel, Werner

    2004-01-01

    Mitogen-activated protein kinases (MAPKs) are inactivated by a dual specificity phosphatase, MAPK phosphatase-1 (MKP-1). MKP-1 is transcribed as an immediate early response gene (IEG) following various stimuli. In the pituitary cell line GH4C1, MKP-1 gene transcription is strongly induced by thyrotropin-releasing hormone (TRH) as well as by epidermal growth factor (EGF) as a consequence of activated MAPK/extracellular-signal-regulated kinase (ERK) signalling. Intriguingly, reporter gene analysis with the MKP-1 promoter showed strong basal transcription, but only limited induction by TRH and EGF. Site-directed mutagenesis of the reporter construct combined with band-shift and in vivo studies revealed that part of the constitutive activity of the MKP-1 promoter resides in two GC boxes bound by Sp1 and Sp3 transcription factors in the minimal promoter. Basal transcription of transiently transfected luciferase reporter can be initiated by either of the two GC boxes or also by either of the two cAMP/Ca(2+) responsive elements or by the E-box present in the proximal promoter. On the other hand, when analysed by stable transfection, the five responsive elements are acting in synergy to transactivate the MKP-1 proximal promoter. We show in this study that the MKP-1 promoter can function as a constitutive promoter or as a rapid and transient sensor for the activation state of MAPKs/ERKs. This dual mode of transcription initiation may have different consequences for the control of a block to elongation situated in the first exon of the MKP-1 gene, as described previously [Ryser, Tortola, van Haasteren, Muda, Li and Schlegel (2001) J. Biol. Chem. 276, 33319-33327]. PMID:14609431

  4. Prevotella intermedia lipopolysaccharide stimulates release of tumor necrosis factor-alpha through mitogen-activated protein kinase signaling pathways in monocyte-derived macrophages.

    Science.gov (United States)

    Kim, Sung-Jo; Choi, Eun-Young; Kim, Eun Gyung; Shin, Su-Hwa; Lee, Ju-Youn; Choi, Jeom-Il; Choi, In-Soon

    2007-11-01

    The purpose of this study was to investigate the effects of lipopolysaccharide from Prevotella intermedia, a major cause of inflammatory periodontal disease, on the production of tumor necrosis factor (TNF)-alpha and the expression of TNF-alpha mRNA in differentiated THP-1 cells, a human monocytic cell line. The potential involvement of the three main mitogen-activated protein kinase (MAPK) signaling pathways in the induction of TNF-alpha production was also investigated. Lipopolysaccharide from P. intermedia ATCC 25611 was prepared by the standard hot phenol-water method. THP-1 cells were incubated in the medium supplemented with phorbol myristate acetate to induce differentiation into macrophage-like cells. It was found that P. intermedia lipopolysaccharide can induce TNF-alpha mRNA expression and stimulate the release of TNF-alpha in differentiated THP-1 cells without additional stimuli. Treatment of the cells with P. intermedia lipopolysaccharide resulted in a simultaneous activation of three MAPKs [extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinase 1/2 (JNK1/2) and p38]. Pretreatment of the cells with MAPK inhibitors effectively suppressed P. intermedia lipopolysaccharide-induced TNF-alpha production without affecting the expression of TNF-alpha mRNA. These data thus provided good evidence that the MAPK signaling pathways are required for the regulation of P. intermedia lipopolysaccharide-induced TNF-alpha synthesis at the level of translation more than at the transcriptional level.

  5. IgA Enhances IGF-1 Mitogenic Activity Via Receptor Modulation in Glomerular Mesangial Cells: Implications for IgA-Induced Nephropathy

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    Amal Al-Eisa

    2017-06-01

    Full Text Available Background/Aim: Glomerulonephritis due to mesangial proliferation is responsible for renal dysfunction in IgA nephropathy (IgAN, however molecular mechanisms of pathogenesis are not well known. We examined the effect of IgA on Insulin-like Growth Factor-1 (IGF-1 activity, a potent mitogen with vital role in growth and development of children, and IGF-1 receptor (IGF-1R in cultures of glomerular mesangial cells (GMC. Methods: GMC were isolated from rat kidneys using sieving and enzymatic digestion of tissue homogenates, and cultured in RPMI 1640 medium. GMC cultures were treated with IgA (0-10 µg/ml in the presence or absence of IGF-1 and fetal bovine serum (FBS, and BrdU incorporation was measured. IGF-1 levels were assayed along with real-time PCR quantification of IGF-1R mRNA. Results: Treatment of GMC with IgA (5 -10 µg/ml significantly (p < 0.01 increased the BrdU incorporation in the presence or absence of FBS or IGF-1. IgA-mediated effects were more pronounced in IGF-1 treated cells that were significantly (p < 0.01 blocked by pretreatment of cells with IGF-1 receptor antibody or genistein. IgA significantly increased the levels of IGF-1 in culture supernatants and GMC homogenates. IGF-1R mRNA was significantly (p < 0.01 increased in IgA treated cells particularly by co-treatment with IGF-1. Conclusion: These findings show that IgA enhances the IGF-1 activity in GMC via stimulation of IGF-1R gene transcription and suggest a role for IGF-1 in pathogenesis of IgAN.

  6. UVB-mediated activation of p38 mitogen-activated protein kinase enhances resistance of normal human keratinocytes to apoptosis by stabilizing cytoplasmic p53.

    Science.gov (United States)

    Chouinard, Nadine; Valerie, Kristoffer; Rouabhia, Mahmoud; Huot, Jacques

    2002-07-01

    Human keratinocytes respond to UV rays by developing a fast adaptive response that contributes to maintaining their functions and survival. We investigated the role of the mitogen-activated protein kinase pathways in transducing the UV signals in normal human keratinocytes. We found that UVA, UVB or UVC induced a marked and persistent activation of p38, whereas c-Jun N-terminal kinase or extracellular signal-regulated kinase were less or not activated respectively. Inhibition of p38 activity by expression of a dominant-negative mutant of p38 or with SB203580 impaired cell viability and led to an increase in UVB-induced apoptosis. This sensitization to apoptosis was independent of caspase activities. Inhibition of p38 did not sensitize transformed HaCaT keratinocytes to UVB-induced apoptosis. In normal keratinocytes, expression of a dominant-negative mutant of p53 increased UVB-induced cell death, pointing to a role for p53. In these cells, UVB triggered a p38-dependent phosphorylation of p53 on Ser-15. This phosphorylation was associated with an SB203580-sensitive accumulation of p53, even in the presence of a serine phosphatase inhibitor. Accumulated p53 was localized mainly in the cytoplasm, independently of CRM1 nuclear export. In HaCaT cells, p53 was localized exclusively in the nucleus and its distribution and level were not affected by UVB or p38 inhibition. However, UVB induced an SB203580-insensitive phosphorylation on Ser-15 of mutated p53. Overall, our results suggest that, in normal human keratinocytes, protection against UVB depends on p38-mediated phosphorylation and stabilization of p53 and is tightly associated with the cytoplasmic sequestration of wild-type p53. We conclude that the p38/p53 pathway plays a key role in the adaptive response of normal human keratinocytes against UV stress.

  7. Influence of physical exercise on interleukin-17, cortisol and melatonin levels in serum, whole blood and mitogen activated peripheral blood mononuclear cells

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    Zarei M.

    2016-10-01

    Full Text Available The purpose of this study was to assay the effect of two months exercise and two months silent on the levels of interleukin-17 (IL-17, melatonin and cortisol in serum, whole blood (WB and peripheral blood mononuclear cells (PBMCs cultures. Thirteen male non-athletic health volunteers participated in a two months moderate exercise program (running %50-%65 VO2 max. The blood samples were collected in three stages, 24 hours before to start exercise, 48 hours and two months after the last session of the training. WB and PBMCs were cultured with mitogens phytohemagglutinin and lipopolysaccharides for 48 hours. The serum and supernatants of WB and PBMCs were analyzed for IL-17, melatonin and cortisol by enzyme-linked immunosorbent assay. Red blood cells (RBC variables were also measured. IL-17 secretion by PBMCs in the post-exercise stage (51.14±5.43 pg/ml compared with pre-exercise (36.74±6.98 pg/ml was increased. But, the amount of melatonin produced by PBMCs in the post- exercise (7.94±0.35 pg/ml, and 2-month silent (6.05±0.27 pg/ml stages compared with pre-exercise (9.16±0.19 pg/ml were decreased. Regardless of the effect of the exercise, PBMcs had more ability to produce IL-17 than WB. As well as, level of cortisol in WB was higher than in serum and PBMCs culture. Mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration RBCs were also increased in post- exercise stage. The other measured parameters were not changed during exercise and recovery. Moderate exercise caused to higher in vitro production of IL-17 and lower production of melatonin by PBMCs.

  8. Inhibitors of the mitogen-activated protein kinase kinase 1/2 signaling pathway clear prion-infected cells from PrPSc.

    Science.gov (United States)

    Nordström, Elin K; Luhr, Katarina M; Ibáñez, Carlos; Kristensson, Krister

    2005-09-14

    Prions represent a unique class of infectious agents in which the normal cellular prion protein (PrPC) is converted to an abnormal isoform (PrPSc), which accumulates in the brain and constitutes the major, if not the only, component of the infectious particle. Factors that still remain to be identified may facilitate the conversion of PrPC to PrPSc. In the present study, we first demonstrated that a growth factor of the neurotrophin family, brain-derived neurotrophic factor (BDNF), stimulates the formation of PrPSc in a gonadotropin-releasing hormone-secreting neuronal cell line (GT1-1 cells) infected with the Rocky Mountain Laboratory (RML) strain of scrapie as determined by Western blot analysis. We then observed that the prion-infected cells can be cleared from PrPSc by treatment with three inhibitors of mitogen-activated protein kinase kinase 1/2 (MEK1/2) [1,4-diamino-2,3-dicyano-1,4-bis(o-aminophenylmercapto)butadiene and 2-(2-amino-3-methyoxyphenyl)-4H-1-benzopyran-4-one, as well as alpha-[amino[(4-aminophenyl)thio]methylene]-2-(trifluoromethyl) benzeneacetonitrile, which passes the blood-brain barrier], a component of one of the intracellular signaling pathways activated by BDNF. The MEK1/2 inhibitors were also efficient in clearing PrPSc from prion-infected GT1-1 cells stimulated to accumulate high levels of PrPSc by enhanced serum concentrations in the medium or by the use of a serum-free neuron-specific neurobasal medium. PrPSc did not reappear in the cultures within 5 weeks after completion of treatment. We conclude that inhibitors of the MEK1/2 pathway can efficiently and probably irreversibly clear PrP(Sc) from prion-infected cells. The MEK pathway may therefore be a suitable target for therapeutic intervention in prion diseases.

  9. MicroRNA-197 reverses the drug resistance of fluorouracil-induced SGC7901 cells by targeting mitogen-activated protein kinase 1

    Science.gov (United States)

    XIONG, HAI-LIN; ZHOU, SI-WEI; SUN, AI-HUA; HE, YING; LI, JUN; YUAN, XIA

    2015-01-01

    MicroRNAs (miRNAs) are a group of small non-coding RNA molecules, which serve an important function in the development of multidrug resistance in cancer through the post-transcriptional regulation of gene expression and RNA silencing. In the present study, the functional effects of miR-197 were analyzed in chemo-resistant gastric cancer cells. Low expression levels of miR-197 were observed in the fluorouracil (5-FU)-resistant gastric cell line SGC7901/5-FU when compared with those in the parental gastric cell line SGC7901. Overexpression of miR-197 in SGC7901/5-FU cells was identified to partially restore 5-FU sensitivity. miRNA target prediction algorithms suggested that mitogen-activated protein kinase 1 (MAPK1) is a candidate target gene for miR-197. A luciferase reporter assay confirmed that miR-197 led to silencing of the MAPK1 gene by recognizing and then specifically binding to the predicted site of the MAPK1 mRNA 3′-untranslated region. When miR-197 was overexpressed in SGC7901 cells, the protein levels of MAPK1 were downregulated. Furthermore, MAPK1 knockdown significantly increased the growth inhibition rate of the SGC7901/5-FU cells compared with those in the control group. These results indicated that miR-197 may influence the sensitivity of 5-FU treatment in a gastric cancer cell line by targeting MAPK1. PMID:26151540

  10. Long-acting β2-agonists increase fluticasone propionate-induced mitogen-activated protein kinase phosphatase 1 (MKP-1 in airway smooth muscle cells.

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    Melanie Manetsch

    Full Text Available Mitogen-activated protein kinase phosphatase 1 (MKP-1 represses MAPK-driven signalling and plays an important anti-inflammatory role in asthma and airway remodelling. Although MKP-1 is corticosteroid-responsive and increased by cAMP-mediated signalling, the upregulation of this critical anti-inflammatory protein by long-acting β2-agonists and clinically-used corticosteroids has been incompletely examined to date. To address this, we investigated MKP-1 gene expression and protein upregulation induced by two long-acting β2-agonists (salmeterol and formoterol, alone or in combination with the corticosteroid fluticasone propionate (abbreviated as fluticasone in primary human airway smooth muscle (ASM cells in vitro. β2-agonists increased MKP-1 protein in a rapid but transient manner, while fluticasone induced sustained upregulation. Together, long-acting β2-agonists increased fluticasone-induced MKP-1 and modulated ASM synthetic function (measured by interleukin 6 (IL-6 and interleukin 8 (IL-8 secretion. As IL-6 expression (like MKP-1 is cAMP/adenylate cyclase-mediated, the long-acting β2-agonist formoterol increased IL-6 mRNA expression and secretion. Nevertheless, when added in combination with fluticasone, β2-agonists significantly repressed IL-6 secretion induced by tumour necrosis factor α (TNFα. Conversely, as IL-8 is not cAMP-responsive, β2-agonists significantly inhibited TNFα-induced IL-8 in combination with fluticasone, where fluticasone alone was without repressive effect. In summary, long-acting β2-agonists increase fluticasone-induced MKP-1 in ASM cells and repress synthetic function of this immunomodulatory airway cell type.

  11. A Comparison Study of Sinusoidal PWM and Space Vector PWM Techniques for Voltage Source Inverter

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    Ömer Türksoy

    2017-06-01

    Full Text Available In this paper, the methods used to control voltage source inverters which have been intensively investigated in recent years are compared. Although the most efficient result is obtained with the least number of switching elements in the inverter topologies, the method used in the switching is at least as effective as the topology. Besides, the selected switching method to control the inverter will play an effective role in suppressing harmonic components while producing the ideal output voltage. There are many derivatives of pulse width modulation techniques that are commonly used to control voltage source inverters. Some of widespread methods are sinusoidal pulse width modulation and space vector pulse width modulation techniques. These modulation techniques used for generating variable frequency and amplitude output voltage in voltage source inverters, have been simulated by using MATLAB/SIMULINK. And, the total harmonic distortions of the output voltages are compared. As a result of simulation studies, sinusoidal pulse width modulation has been found to have more total harmonic distortion in output voltages of voltage source inverters in the simulation. Space vector pulse width modulation has been shown to produce a more efficient output voltage with less total harmonic distortion.

  12. Nitric oxide mediates the indole acetic acid induction activation of a mitogen-activated protein kinase cascade involved in adventitious root development.

    Science.gov (United States)

    Pagnussat, Gabriela Carolina; Lanteri, María Luciana; Lombardo, María Cristina; Lamattina, Lorenzo

    2004-05-01

    Recently, it was demonstrated that nitric oxide (NO) and cGMP are involved in the auxin response during the adventitious rooting process in cucumber (Cucumis sativus; Pagnussat et al., 2002, 2003). However, not much is known about the complex molecular network operating during the cell proliferation and morphogenesis triggered by auxins and NO in that process. Anatomical studies showed that formation of adventitious root primordia was clearly detected in indole acetic acid (IAA)- and NO-treated cucumber explants, while neither cell proliferation nor differentiation into root primordia could be observed in control explants 3 d after primary root was removed. In order to go further with signal transduction mechanisms that operate during IAA- and NO-induced adventitious root formation, experiments were designed to test the involvement of a mitogen-activated protein kinase (MAPK) cascade in that process. Cucumber explants were treated with the NO-donor sodium nitroprusside (SNP) or with SNP plus the specific NO-scavenger cPTIO. Protein extracts from those explants were assayed for protein kinase (PK) activity by using myelin basic protein (MBP) as substrate in both in vitro and in-gel assays. The activation of a PK of approximately 48 kD could be detected 1 d after NO treatment with a maximal activation after 3 d of treatment. In control explants, a PK activity was detected only after 4 d of treatment. The MBP-kinase activity was also detected in extracts from IAA-treated explants, while no signal was observed in IAA + cPTIO treatments. The PK activity could be inhibited by the cell-permeable MAPK kinase inhibitor PD098059, suggesting that the NO-dependent MBP-kinase activity is a MAPK. Furthermore, when PD098059 was administered to explants treated with SNP or IAA, it produced a delay in root emergence and a dose-dependent reduction in root number. Altogether, our results suggest that a MAPK signaling cascade is activated during the adventitious rooting process

  13. Nicotine stimulates urokinase-type plasminogen activator receptor expression and cell invasiveness through mitogen-activated protein kinase and reactive oxygen species signaling in ECV304 endothelial cells

    International Nuclear Information System (INIS)

    Khoi, Pham Ngoc; Park, Jung Sun; Kim, Nam Ho; Jung, Young Do

    2012-01-01

    Urokinase-type plasminogen activator receptor (uPAR) expression is elevated during inflammation, tissue remodeling and in many human cancers. This study investigated the effect of nicotine, a major alkaloid in tobacco, on uPAR expression and cell invasiveness in ECV304 endothelial cells. Nicotine stimulated uPAR expression in a dose-dependent manner and activated extracellular signal-regulated kinases-1/2 (Erk-1/2), c-Jun amino-terminal kinase (JNK) and p38 mitogen activated protein kinase (MAPK). Specific inhibitors of MEK-1 (PD98059) and JNK (SP600125) inhibited the nicotine-induced uPAR expression, while the p38 MAPK inhibitor SB203580 did not. Expression vectors encoding dominant negative MEK-1 (pMCL-K97M) and JNK (TAM67) also prevented nicotine-induced uPAR promoter activity. The intracellular hydrogen peroxide (H 2 O 2 ) content was increased by nicotine treatment. The antioxidant N-acetylcysteine prevented nicotine-activated production of reactive oxygen species (ROS) and uPAR expression. Furthermore, exogenous H 2 O 2 increased uPAR mRNA expression. Deleted and site-directed mutagenesis demonstrated the involvement of the binding sites of transcription factor nuclear factor-kappaB (NF-κB) and activator protein (AP)-1 in the nicotine-induced uPAR expression. Studies with expression vectors encoding mutated NF-κB signaling molecules and AP-1 decoy confirmed that NF-κB and AP-1 were essential for the nicotine-stimulated uPAR expression. MAPK (Erk-1/2 and JNK) and ROS functioned as upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. In addition, ECV304 endothelial cells treated with nicotine displayed markedly enhanced invasiveness, which was partially abrogated by uPAR neutralizing antibodies. The data indicate that nicotine induces uPAR expression via the MAPK/AP-1 and ROS/NF-κB signaling pathways and, in turn, stimulates invasiveness in human ECV304 endothelial cells. -- Highlights: ► Endothelial cells treated with nicotine

  14. Nicotine stimulates urokinase-type plasminogen activator receptor expression and cell invasiveness through mitogen-activated protein kinase and reactive oxygen species signaling in ECV304 endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Khoi, Pham Ngoc; Park, Jung Sun; Kim, Nam Ho; Jung, Young Do, E-mail: ydjung@chonnam.ac.kr

    2012-03-01

    Urokinase-type plasminogen activator receptor (uPAR) expression is elevated during inflammation, tissue remodeling and in many human cancers. This study investigated the effect of nicotine, a major alkaloid in tobacco, on uPAR expression and cell invasiveness in ECV304 endothelial cells. Nicotine stimulated uPAR expression in a dose-dependent manner and activated extracellular signal-regulated kinases-1/2 (Erk-1/2), c-Jun amino-terminal kinase (JNK) and p38 mitogen activated protein kinase (MAPK). Specific inhibitors of MEK-1 (PD98059) and JNK (SP600125) inhibited the nicotine-induced uPAR expression, while the p38 MAPK inhibitor SB203580 did not. Expression vectors encoding dominant negative MEK-1 (pMCL-K97M) and JNK (TAM67) also prevented nicotine-induced uPAR promoter activity. The intracellular hydrogen peroxide (H{sub 2}O{sub 2}) content was increased by nicotine treatment. The antioxidant N-acetylcysteine prevented nicotine-activated production of reactive oxygen species (ROS) and uPAR expression. Furthermore, exogenous H{sub 2}O{sub 2} increased uPAR mRNA expression. Deleted and site-directed mutagenesis demonstrated the involvement of the binding sites of transcription factor nuclear factor-kappaB (NF-κB) and activator protein (AP)-1 in the nicotine-induced uPAR expression. Studies with expression vectors encoding mutated NF-κB signaling molecules and AP-1 decoy confirmed that NF-κB and AP-1 were essential for the nicotine-stimulated uPAR expression. MAPK (Erk-1/2 and JNK) and ROS functioned as upstream signaling molecules in the activation of AP-1 and NF-κB, respectively. In addition, ECV304 endothelial cells treated with nicotine displayed markedly enhanced invasiveness, which was partially abrogated by uPAR neutralizing antibodies. The data indicate that nicotine induces uPAR expression via the MAPK/AP-1 and ROS/NF-κB signaling pathways and, in turn, stimulates invasiveness in human ECV304 endothelial cells. -- Highlights: ► Endothelial cells

  15. The quiescent and mitogen stimulated peripheral blood mononuclear cells after gamma irradiation and their P53, P21 and H2AX expression

    International Nuclear Information System (INIS)

    Vilasova, Z.; Vavrova, J.; Sinkorova, Z.; Tichy, A.; Oesterreicher, J.; Rezacova, M.; Zoelzer, F.

    2008-01-01

    The aim of this study was to compare reaction of quiescent and proliferating PHA (mitogenic lectin phytohemagglutinin)-stimulated human peripheral blood mononuclear cells (PBMCs) to γ-irradiation and analyze changes of proteins related to repair if DNA damage and apoptosis, such as γH2A.X, p53 and its phosphorylations on serine 15 and 392, and p21. Protein changes induced by radiation are different in quiescent and stimulated PBMCs. W e analyzed changes in proteins related to DNA damage repair and apoptosis using the western blot method in quiescent and stimulated PBMCs. Western blot technique can detect γH2A.X increase only at later times, when the phosphorylation of H2A.X is related to the onset of apoptosis (24-72 h after irradiation by the dose of 4 Gy). The level of H2A.X phosphorylation increased after stimulation of PBMC by PHA (72 h, 10 μg/ml) and as shown here it was detectable by western blot analysis. The increase in γH2A.X that we detected by western blot 4 h after irradiation of stimulated lymphocytes was dose dependent. It can be concluded that measurement of γH2A.X during the first hours after the irradiation is a good marker of the received dose of radiation. We compared the dynamics of p53 induction after irradiation by IR in both quiescent and stimulated lymphocytes. p53 increase was observed only in stimulated lymphocytes, as was p53 phosphorylation at serines-392 and -15. The increase in the amount of p53 was not dose-dependent 4 h after the irradiation. On the other hand, phosphorylation of p53 at serine-15 analyzed 4 h after the irradiation is dose-dependent over the studied dose range. Despite the fact that p53 was not detected in quiescent lymphocytes and a reaction to irradiation was not observed either, p21 levels increased after irradiation in both quiescent and stimulated lymphocytes in a dose-dependent manner. IR induces phosphorylation of p53 at both serines-15 and -392 in PHA stimulated human lymphocytes. However

  16. A mitogen-activated protein kinase Tmk3 participates in high osmolarity resistance, cell wall integrity maintenance and cellulase production regulation in Trichoderma reesei.

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    Mingyu Wang

    Full Text Available The mitogen-activated protein kinase (MAPK pathways are important signal transduction pathways conserved in essentially all eukaryotes, but haven't been subjected to functional studies in the most important cellulase-producing filamentous fungus Trichoderma reesei. Previous reports suggested the presence of three MAPKs in T. reesei: Tmk1, Tmk2, and Tmk3. By exploring the phenotypic features of T. reesei Δtmk3, we first showed elevated NaCl sensitivity and repressed transcription of genes involved in glycerol/trehalose biosynthesis under higher osmolarity, suggesting Tmk3 participates in high osmolarity resistance via derepression of genes involved in osmotic stabilizer biosynthesis. We also showed significant downregulation of genes encoding chitin synthases and a β-1,3-glucan synthase, decreased chitin content, 'budded' hyphal appearance typical to cell wall defective strains, and increased sensitivity to calcofluor white/Congo red in the tmk3 deficient strain, suggesting Tmk3 is involved in cell wall integrity maintenance in T. reesei. We further observed the decrease of cellulase transcription and production in T. reesei Δtmk3 during submerged cultivation, as well as the presence of MAPK phosphorylation sites on known transcription factors involved in cellulase regulation, suggesting Tmk3 is also involved in the regulation of cellulase production. Finally, the expression of cell wall integrity related genes, the expression of cellulase coding genes, cellulase production and biomass accumulation were compared between T. reesei Δtmk3 grown in solid state media and submerged media, showing a strong restoration effect in solid state media from defects resulted from tmk3 deletion. These results showed novel physiological processes that fungal Hog1-type MAPKs are involved in, and present the first experimental investigation of MAPK signaling pathways in T. reesei. Our observations on the restoration effect during solid state cultivation suggest

  17. N-Farnesyloxy-norcantharimide inhibits progression of human leukemic Jurkat T cells through regulation of mitogen-activated protein kinase and interleukin-2 production.

    Science.gov (United States)

    Chang, Ming-Che; Wu, Jin-Yi; Liao, Hui-Fen; Chen, Yu-Jen; Kuo, Cheng-Deng

    2015-11-01

    This study investigated the anticancer effects of N-farnesyloxy-norcantharimide (NOC15), a newly synthesized norcantharidin (NCTD) analogue, on human leukemic Jurkat T cells and the signaling pathway underlying its effects. We found that the half maximal inhibitory concentration (IC50) of NOC15 on Jurkat T cells is 1.4 μmol/l, which is 11.14-fold (=15.6÷1.4) smaller than the 15.6 μmol/l of NCTD on Jurkat T cells, whereas the IC50 of NOC15 on human normal lymphoblast (HNL) is 207.9 μmol/l, which is 8.17-fold (=1698.0÷207.8) smaller than the 1698.0 μmol/l of NCTD on HNL cells. These results indicated that NOC15 exerts a higher anticancer effect on Jurkat T cells and has higher toxicity toward HNL cells than NCTD. Thus, NOC15 is 1.36-fold (=11.14÷8.17) beneficial as an anticancer agent toward Jurkat T cells compared with NCTD. Moreover, NOC15 can increase the percentage of cells in the sub-G1 phase and reduce the cell viability of Jurkat T cells, stimulate p38 and extracellular signal-regulated protein kinase 1/2 (ERK1/2) of mitogen-activated protein kinases (MAPKs) signaling pathway, and inhibit calcineurin expression and interleukin-2 (IL-2) production. However, NOC15 exerted no effects on the Jun-N-terminal kinase 1/2 (JNK1/2) signaling pathway, the production of IL-8, and tumor necrosis factor-α. We conclude that the anticancer activity of the newly synthesized NOC15 is 1.36-fold beneficial than NCTD as an anticancer agent and that NOC15 can increase the percentage of cells in the sub-G1 phase through the stimulation of p38 and ERK1/2 of the MAPK signaling pathway and the inhibition of calcineurin expression and IL-2 production. The NOC15 may have the potential of being developed into an anticancer agent in the future.

  18. Mitogen-activated protein kinase kinase 1/2 inhibition and angiotensin II converting inhibition in mice with cardiomyopathy caused by lamin A/C gene mutation

    Energy Technology Data Exchange (ETDEWEB)

    Muchir, Antoine, E-mail: a.muchir@institut-myologie.org [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Wu, Wei [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Sera, Fusako; Homma, Shunichi [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Worman, Howard J., E-mail: hjw14@columbia.edu [Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY (United States); Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, NY (United States)

    2014-10-03

    Highlights: • Both ACE and MEK1/2 inhibition are beneficial on cardiac function in Lmna cardiomyopathy. • MEK1/2 inhibitor has beneficial effects beyond ACE inhibition for Lmna cardiomyopathy. • These results provide further preclinical rationale for a clinical trial of a MEK1/2 inhibitor. - Abstract: Background: Mutations in the LMNA gene encoding A-type nuclear lamins can cause dilated cardiomyopathy with or without skeletal muscular dystrophy. Previous studies have shown abnormally increased extracellular signal-regulated kinase 1/2 activity in hearts of Lmna{sup H222P/H222P} mice, a small animal model. Inhibition of this abnormal signaling activity with a mitogen-activated protein kinase kinase 1/2 (MEK1/2) inhibitor has beneficial effects on heart function and survival in these mice. However, such treatment has not been examined relative to any standard of care intervention for dilated cardiomyopathy or heart failure. We therefore examined the effects of an angiotensin II converting enzyme (ACE) inhibitor on left ventricular function in Lmna{sup H222P/H222P} mice and assessed if adding a MEK1/2 inhibitor would provide added benefit. Methods: Male Lmna{sup H222P/H222P} mice were treated with the ACE inhibitor benazepril, the MEK1/2 inhibitor selumetinib or both. Transthoracic echocardiography was used to measure left ventricular diameters and fractional shortening was calculated. Results: Treatment of Lmna{sup H222P/H222P} mice with either benazepril or selumetinib started at 8 weeks of age, before the onset of detectable left ventricular dysfunction, lead to statistically significantly increased fractional shortening compared to placebo at 16 weeks of age. There was a trend towards a great value for fractional shortening in the selumetinib-treated mice. When treatment was started at 16 weeks of age, after the onset of left ventricular dysfunction, the addition of selumetinib treatment to benazepril lead to a statistically significant increase in left

  19. Effects of estrogens and bladder inflammation on mitogen-activated protein kinases in lumbosacral dorsal root ganglia from adult female rats

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    Keast Janet R

    2009-12-01

    Full Text Available Abstract Background Interstitial cystitis is a chronic condition associated with bladder inflammation and, like a number of other chronic pain states, symptoms associated with interstitial cystitis are more common in females and fluctuate during the menstrual cycle. The aim of this study was to determine if estrogens could directly modulate signalling pathways within bladder sensory neurons, such as extracellular signal-related kinase (ERK and p38 mitogen-activated protein (MAP kinases. These signalling pathways have been implicated in neuronal plasticity underlying development of inflammatory somatic pain but have not been as extensively investigated in visceral nociceptors. We have focused on lumbosacral dorsal root ganglion (DRG neurons projecting to pelvic viscera (L1, L2, L6, S1 of adult female Sprague-Dawley rats and performed both in vitro and in vivo manipulations to compare the effects of short- and long-term changes in estrogen levels on MAPK expression and activation. We have also investigated if prolonged estrogen deprivation influences the effects of lower urinary tract inflammation on MAPK signalling. Results In studies of isolated DRG neurons in short-term (overnight culture, we found that estradiol and estrogen receptor (ER agonists rapidly stimulated ER-dependent p38 phosphorylation relative to total p38. Examination of DRGs following chronic estrogen deprivation in vivo (ovariectomy showed a parallel increase in total and phosphorylated p38 (relative to β-tubulin. We also observed an increase in ERK1 phosphorylation (relative to total ERK1, but no change in ERK1 expression (relative to β-tubulin. We observed no change in ERK2 expression or phosphorylation. Although ovariectomy increased the level of phosphorylated ERK1 (vs. total ERK1, cyclophosphamide-induced lower urinary tract inflammation did not cause a net increase of either ERK1 or ERK2, or their phosphorylation. Inflammation did, however, cause an increase in p38

  20. Wheat mitogen-activated protein kinase gene TaMPK4 improves plant tolerance to multiple stresses through modifying root growth, ROS metabolism, and nutrient acquisitions.

    Science.gov (United States)

    Hao, Lin; Wen, Yanli; Zhao, Yuanyuan; Lu, Wenjing; Xiao, Kai

    2015-12-01

    Wheat MAPK member TaMPK4 responds to abiotic stresses of Pi and N deprivations and high salinity and is crucial in regulating plant tolerance to aforementioned stresses. Mitogen-activated protein kinase (MAPK) cascades are important signal transduction modules in regulating plant responses to various environmental stresses. In this study, a wheat MAPK member referred to TaMPK4 was characterized for its roles in mediating plant tolerance to diverse stresses. TaMPK4 shares conserved domains generally identified in plant MAPKs and possesses in vitro kinase activity. Under stresses of Pi and N deprivations and high salinity, TaMPK4 was strongly upregulated and its expressions were restored upon recovery treatments from above stresses. Sense- and antisense-expressing TaMPK4 in tobacco significantly modified plant growth under the stress conditions and dramatically modified the root architecture through transcriptional regulation of the auxin transport-associated genes NtPIN3 and NtPIN9, whose downregulated expressions dramatically reduced the root growth. Compared with wild type (WT), the antioxidant enzymatic activities under the stress conditions, P accumulation under P deprivation, and N amount under N deficiency were altered dramatically in the transgenic plants, showing higher in the TaMPK4-overexpressing and lower in the TaMPK4-knockout plants, which were in concordance with the modified expressions of a set of antioxidant enzyme genes (NtPOD2;1, NtPOD9, NtSOD2, NtFeSOD, and NtCAT), two phosphate transporter genes (NtPT and NtPT2), and two nitrate transporter genes (NtNRT1.1-s and NtNRT1.1-t), respectively. Downregulated expression of above genes in tobacco largely reduced the plant growth, and Pi and N acquisitions under the stress conditions. TaMPK4 also involved regulations of plant K(+) and osmolyte contents under high salinity. Thus, TaMPK4 is functional in regulating plant tolerance to diverse stresses through modifying various biological processes.

  1. Mitogen-activated protein kinases and NFκB are involved in SP-A-enhanced responses of macrophages to mycobacteria

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    Vigerust David J

    2009-07-01

    Full Text Available Abstract Background Surfactant protein A (SP-A is a C-type lectin involved in surfactant homeostasis as well as host defense in the lung. We have recently demonstrated that SP-A enhances the killing of bacillus Calmette-Guerin (BCG by rat macrophages through a nitric oxide-dependent pathway. In the current study we have investigated the role of tyrosine kinases and the downstream mitogen-activated protein kinase (MAPK family, and the transcription factor NFκB in mediating the enhanced signaling in response to BCG in the presence of SP-A. Methods Human SP-A was prepared from alveolar proteinosis fluid, and primary macrophages were obtained by maturation of cells from whole rat bone marrow. BCG-SP-A complexes were routinely prepared by incubation of a ratio of 20 μg of SP-A to 5 × 105 BCG for 30 min at 37°C. Cells were incubated with PBS, SP-A, BCG, or SP-A-BCG complexes for the times indicated. BCG killing was assessed using a 3H-uracil incorporation assay. Phosphorylated protein levels, enzyme assays, and secreted mediator assays were conducted using standard immunoblot and biochemical methods as outlined. Results Involvement of tyrosine kinases was demonstrated by herbimycin A-mediated inhibition of the SP-A-enhanced nitric oxide production and BCG killing. Following infection of macrophages with BCG, the MAPK family members ERK1 and ERK2 were activated as evidence by increased tyrosine phosphorylation and enzymatic activity, and this activation was enhanced when the BCG were opsonized with SP-A. An inhibitor of upstream kinases required for ERK activation inhibited BCG- and SP-A-BCG-enhanced production of nitric oxide by approximately 35%. Macrophages isolated from transgenic mice expressing a NFκB-responsive luciferase gene showed increased luciferase activity following infection with BCG, and this activity was enhanced two-fold in the presence of SP-A. Finally, lactacystin, an inhibitor of IκB degradation, reduced BCG- and SP

  2. EphA2 modulates radiosensitive of hepatocellular carcinoma cells via p38/mitogen-activated protein kinase-mediated signal pathways

    Directory of Open Access Journals (Sweden)

    Qiao Jin

    2015-10-01

    Full Text Available This experiment was conducted to investigate the role of EPH receptor A2 (EphA2 in the modulation of radiosensitivity of hepatic cellular cancer (HCC cells and to determine whether p38/mitogen-activated protein kinase (p38MAPK signaling mediated EphA2 function in this respect. The protein expressions of EphA2 and phosphorylated p38MAPK were tested in HCC and normal hepatic tissues. In HCC 97H cells, EphA2 was overexpressed and knocked out by transfection with EphA2 expression vector and EphA2-ShRNA, respectively, prior to cell exposure to low-dose irradiation. Significantly upregulated EphA2 and phosphorylated p38MAPK were observed in HCC tissues, compared with those in normal hepatic tissues. Low-dose irradiation (1 Gy only caused minor damage to HCC 97H cells, as assessed by alterations in cell viability, apoptosis rate, and cell healing capacity (p = 0.072, p = 0.078, and p = 0.069 respectively. However, EphA2 knock-out in HCC 97H cells induced significant reduction in cell viability and cell healing capacity after these cells were subjected to low-dose irradiation. Apoptosis rate underwent dramatic increase (p < 0.01. By contrast, EphA2 overexpression in HCC 97H cells reversed these effects and enhanced cell colony formation rate, thus displaying remarkable attenuation of radiosensitivity of HCC 97H cells. Further, SB203580, a specific inhibitor of p38MAPK, was added to HCC 97H cells over-expressing EphA2. The effect of EphA2 overexpression on the radiosensitivity of HCC 97H cells was abrogated. Thus, the present study indicates that EphA2 have the ability to negatively regulate the radiosensitivity of HCC 97H cells, which mainly depends on 38MAPK-mediated signal pathways.

  3. Bioactive glass induced osteogenic differentiation of human adipose stem cells is dependent on cell attachment mechanism and mitogen-activated protein kinases.

    Science.gov (United States)

    Ojansivu, M; Hyväri, L; Kellomäki, M; Hupa, L; Vanhatupa, S; Miettinen, S

    2018-01-30

    Bioactive glasses (BaGs) are widely utilised in bone tissue engineering (TE) but the molecular response of cells to BaGs is poorly understood. To elucidate the mechanisms of cell attachment to BaGs and BaG-induced early osteogenic differentiation, we cultured human adipose stem cells (hASCs) on discs of two silica-based BaGs S53P4 (23.0 Na2O - 20.0 CaO - 4.0 P2O5 - 53.0 SiO2 (wt-%)) and 1-06 (5.9 Na2O - 12.0 K2O - 5.3 MgO - 22.6 CaO - 4.0 P2O5 - 0.2 B2O3 - 50.0 SiO2) in the absence of osteogenic supplements. Both BaGs induced early osteogenic differentiation by increasing alkaline phosphatase activity (ALP) and the expression of osteogenic marker genes RUNX2a and OSTERIX. Based on ALP activity, the slower reacting 1-06 glass was a stronger osteoinducer. Regarding the cell attachment, cells cultured on BaGs had enhanced integrinβ1 and vinculin production, and mature focal adhesions were smaller but more dispersed than on cell culture plastic (polystyrene). Focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK)-induced c-Jun phosphorylations were upregulated by glass contact. Moreover, the BaG-stimulated osteoinduction was significantly reduced by FAK and mitogen-activated protein kinase (MAPK) inhibitors, indicating an important role for FAK and MAPKs in the BaG-induced early osteogenic commitment of hASCs. Upon indirect insert culture, the ions released from the BaG discs could not reproduce the observed cellular changes, which highlighted the role of direct cell-BaG interactions in the osteopotential of BaGs. These findings gave valuable insight into the mechanism of BaG-induced osteogenic differentiation and therefore provided knowledge to aid the future design of new functional biomaterials to meet the increasing demand for clinical bone TE treatments.

  4. Phosphorylation and activation of p42 and p44 mitogen-activated protein kinase are required for the P2 purinoceptor stimulation of endothelial prostacyclin production.

    Science.gov (United States)

    Patel, V; Brown, C; Goodwin, A; Wilkie, N; Boarder, M R

    1996-11-15

    Extracellular ATP and ADP, released from platelets and other sites stimulate the endothelial production of prostacyclin (PGI2) by acting on G-protein-coupled P2Y2 and P2Y2 purinoceptors, contributing to the maintenance of a non-thrombogenic surface. The mechanism, widely described as being dependent on elevated cytosolic [Ca2+], also requires protein tyrosine phosphorylation. Here we show that activation of both these P2 receptor types leads to the tyrosine phosphorylation and activation of both the p42 and p44 forms of mitogen-activated protein kinase (MAPK). 2-Methylthio-ATP and UTP, selectively activating P2Y1 and P2Y2 purinoceptors respectively, and ATP, a non-selective agonist at these two receptors, stimulate the tyrosine phosphorylation of both p42mapk and p44mapk, as revealed by Western blots with an antiserum specific for the tyrosine-phosphorylated forms of the enzymes. By using separation on Resource Q columns, peptide kinase activity associated with the phosphorylated MAPK enzymes distributes into two peaks, one mainly p42mapk and one mainly p44mapk, both of which are stimulated by ATP with respect to kinase activity and phospho-MAPK immunoreactivity. Stimulation of P2Y1 or P2Y2 purinoceptors leads to a severalfold increase in PGI2 efflux; this was blocked in a dose-dependent manner by the selective MAPK kinase inhibitor PD98059. This drug also blocked the agonist-stimulated increase in phospho-MAPK immunoreactivity for both p42mapk and p44mapk but left the phospholipase C response to P2 agonists essentially unchanged. Olomoucine has been reported to inhibit p44mapk activity. Here we show that in the same concentration range olomoucine inhibits activity in both peaks from the Resource Q column and also the agonist stimulation of 6-keto-PGF1, but has no effect on agonist-stimulated phospho-MAPK immunoreactivity. These results provide direct evidence for the involvement of p42 and p44 MAPK in the PGI2 response of intact endothelial cells: we have shown

  5. Blockade of adenosine A2A receptors prevents interleukin-1β-induced exacerbation of neuronal toxicity through a p38 mitogen-activated protein kinase pathway

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    Simões Ana

    2012-08-01

    Full Text Available Abstract Background and purpose Blockade of adenosine A2A receptors (A2AR affords robust neuroprotection in a number of brain conditions, although the mechanisms are still unknown. A likely candidate mechanism for this neuroprotection is the control of neuroinflammation, which contributes to the amplification of neurodegeneration, mainly through the abnormal release of pro-inflammatory cytokines such as interleukin(IL-1β. We investigated whether A2AR controls the signaling of IL-1β and its deleterious effects in cultured hippocampal neurons. Methods Hippocampal neuronal cultures were treated with IL-1β and/or glutamate in the presence or absence of the selective A2AR antagonist, SCH58261 (50 nmol/l. The effect of SCH58261 on the IL-1β-induced phosphorylation of the mitogen-activated protein kinases (MAPKs c-Jun N-terminal kinase (JNK and p38 was evaluated by western blotting and immunocytochemistry. The effect of SCH58261 on glutamate-induced neurodegeneration in the presence or absence of IL-1β was evaluated by nucleic acid and by propidium iodide staining, and by lactate dehydrogenase assay. Finally, the effect of A2AR blockade on glutamate-induced intracellular calcium, in the presence or absence of IL-1β, was studied using single-cell calcium imaging. Results IL-1β (10 to 100 ng/ml enhanced both JNK and p38 phosphorylation, and these effects were prevented by the IL-1 type 1 receptor antagonist IL-1Ra (5 μg/ml, in accordance with the neuronal localization of IL-1 type 1 receptors, including pre-synaptically and post-synaptically. At 100 ng/ml, IL-1β failed to affect neuronal viability but exacerbated the neurotoxicity induced by treatment with 100 μmol/l glutamate for 25 minutes (evaluated after 24 hours. It is likely that this resulted from the ability of IL-1β to enhance glutamate-induced calcium entry and late calcium deregulation, both of which were unaffected by IL-1β alone. The selective A2AR antagonist, SCH58261 (50 nmol

  6. Adenosine A2A receptor blockade prevents synaptotoxicity and memory dysfunction caused by beta-amyloid peptides via p38 mitogen-activated protein kinase pathway.

    Science.gov (United States)

    Canas, Paula M; Porciúncula, Lisiane O; Cunha, Geanne M A; Silva, Carla G; Machado, Nuno J; Oliveira, Jorge M A; Oliveira, Catarina R; Cunha, Rodrigo A

    2009-11-25

    Alzheimer's disease (AD) is characterized by memory impairment, neurochemically by accumulation of beta-amyloid peptide (namely Abeta(1-42)) and morphologically by an initial loss of nerve terminals. Caffeine consumption prevents memory dysfunction in different models, which is mimicked by antagonists of adenosine A(2A) receptors (A(2A)Rs), which are located in synapses. Thus, we now tested whether A(2A)R blockade prevents the early Abeta(1-42)-induced synaptotoxicity and memory dysfunction and what are the underlying signaling pathways. The intracerebral administration of soluble Abeta(1-42) (2 nmol) in rats or mice caused, 2 weeks later, memory impairment (decreased performance in the Y-maze and object recognition tests) and a loss of nerve terminal markers (synaptophysin, SNAP-25) without overt neuronal loss, astrogliosis, or microgliosis. These were prevented by pharmacological blockade [5-amino-7-(2-phenylethyl)-2-(2-furyl)-pyrazolo[4,3-e]-1,2,4-triazolo[1,5-c]pyrimidine (SCH58261); 0.05 mg . kg(-1) . d(-1), i.p.; for 15 d] in rats, and genetic inactivation of A(2A)Rs in mice. Moreover, these were synaptic events since purified nerve terminals acutely exposed to Abeta(1-42) (500 nm) displayed mitochondrial dysfunction, which was prevented by A(2A)R blockade. SCH58261 (50 nm) also prevented the initial synaptotoxicity (loss of MAP-2, synaptophysin, and SNAP-25 immunoreactivity) and subsequent loss of viability of cultured hippocampal neurons exposed to Abeta(1-42) (500 nm). This A(2A)R-mediated control of neurotoxicity involved the control of Abeta(1-42)-induced p38 phosphorylation and was independent from cAMP/PKA (protein kinase A) pathway. Together, these results show that A(2A)Rs play a crucial role in the development of Abeta-induced synaptotoxicity leading to memory dysfunction through a p38 MAPK (mitogen-activated protein kinase)-dependent pathway and provide a molecular basis for the benefits of caffeine consumption in AD.

  7. Biodentine induces human dental pulp stem cell differentiation through mitogen-activated protein kinase and calcium-/calmodulin-dependent protein kinase II pathways.

    Science.gov (United States)

    Luo, Zhirong; Kohli, Meetu R; Yu, Qing; Kim, Syngcuk; Qu, Tiejun; He, Wen-xi

    2014-07-01

    Biodentine (Septodont, Saint-Maur-des-Fossès, France), a new tricalcium silicate cement formulation, has been introduced as a bioactive dentine substitute to be used in direct contact with pulp tissue. The aim of this study was to investigate the response of human dental pulp stem cells (hDPSCs) to the material and whether mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF-κB), and calcium-/calmodulin-dependent protein kinase II (CaMKII) signal pathways played a regulatory role in Biodentine-induced odontoblast differentiation. hDPCs obtained from impacted third molars were incubated with Biodentine. Odontoblastic differentiation was evaluated by alkaline phosphatase activity, alizarin red staining, and quantitative real-time reverse-transcriptase polymerase chain reaction for the analysis of messenger RNA expression of the following differentiation gene markers: osteocalcin (OCN), dentin sialophosprotein (DSPP), dentin matrix protein 1 (DMP1), and bone sialoprotein (BSP). Cell cultures in the presence of Biodentine were exposed to specific inhibitors of MAPK (U0126, SB203580, and SP600125), NF-κB (pyrrolidine dithiocarbamate), and CaMKII (KN-93) pathways to evaluate the regulatory effect on the expression of these markers and mineralization assay. Biodentine significantly increased alkaline phosphatase activity and mineralized nodule formation and the expression of OCN, DSPP, DMP1, and BSP. The MAPK inhibitor for extracellular signal-regulated kinase 1/2 (U0126) and Jun N-terminal kinase (SP600125) significantly decreased the Biodentine-induced mineralized differentiation of hDPSCs and OCN, DSPP, DMP1, and BSP messenger RNA expression, whereas p38 MAPK inhibitors (SB203580) had no effect. The CaMKII inhibitor KN-93 significantly attenuated and the NF-κB inhibitor pyrrolidine dithiocarbamate further enhanced the up-regulation of Biodentine-induced gene expression and mineralization. Biodentine is a bioactive and biocompatible material capable

  8. A Role for Protein Phosphatase 2A in Regulating p38 Mitogen Activated Protein Kinase Activation and Tumor Necrosis Factor-Alpha Expression during Influenza Virus Infection

    Directory of Open Access Journals (Sweden)

    Anna H. Y. Law

    2013-04-01

    Full Text Available Influenza viruses of avian origin continue to pose pandemic threats to human health. Some of the H5N1 and H9N2 virus subtypes induce markedly elevated cytokine levels when compared with the seasonal H1N1 virus. We previously showed that H5N1/97 hyperinduces tumor necrosis factor (TNF-alpha through p38 mitogen activated protein kinase (MAPK. However, the detailed mechanisms of p38MAPK activation and TNF-alpha hyperinduction following influenza virus infections are not known. Negative feedback regulations of cytokine expression play important roles in avoiding overwhelming production of proinflammatory cytokines. Here we hypothesize that protein phosphatases are involved in the regulation of cytokine expressions during influenza virus infection. We investigated the roles of protein phosphatases including MAPK phosphatase-1 (MKP-1 and protein phosphatase type 2A (PP2A in modulating p38MAPK activation and downstream TNF-alpha expressions in primary human monocyte-derived macrophages (PBMac infected with H9N2/G1 or H1N1 influenza virus. We demonstrate that H9N2/G1 virus activated p38MAPK and hyperinduced TNF-alpha production in PBMac when compared with H1N1 virus. H9N2/G1 induced PP2A activity in PBMac and, with the treatment of a PP2A inhibitor, p38MAPK phosphorylation and TNF-alpha production were further increased in the virus-infected macrophages. However, H9N2/G1 did not induce the expression of PP2A indicating that the activation of PP2A is not mediated by p38MAPK in virus-infected PBMac. On the other hand, PP2A may not be the targets of H9N2/G1 in the upstream of p38MAPK signaling pathways since H1N1 also induced PP2A activation in primary macrophages. Our results may provide new insights into the control of cytokine dysregulation.

  9. The Role of Mitogen-Activated Protein (MAP Kinase Signaling Components in the Fungal Development, Stress Response and Virulence of the Fungal Cereal Pathogen Bipolaris sorokiniana.

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    Yueqiang Leng

    Full Text Available Mitogen-activated protein kinases (MAPKs have been demonstrated to be involved in fungal development, sexual reproduction, pathogenicity and/or virulence in many filamentous plant pathogenic fungi, but genes for MAPKs in the fungal cereal pathogen Bipolaris sorokiniana have not been characterized. In this study, orthologues of three MAPK genes (CsSLT2, CsHOG1 and CsFUS3 and one MAPK kinase kinase (MAPKKK gene (CsSTE11 were identified in the whole genome sequence of the B. sorokiniana isolate ND90Pr, and knockout mutants were generated for each of them. The ∆Csfus3 and ∆Csste11 mutants were defective in conidiation and formation of appressoria-like structures, showed hypersensitivity to oxidative stress and lost pathogenicity on non-wounded leaves of barley cv. Bowman. When inoculated on wounded leaves of Bowman, the ∆Csfus3 and ∆Csste11 mutants were reduced in virulence compared to the wild type. No morphological changes were observed in the ∆Cshog1 mutants in comparison with the wild type; however, they were slightly reduced in growth under oxidative stress and were hypersensitive to hyperosmotic stress. The ∆Cshog1 mutants formed normal appressoria-like structures but were reduced in virulence when inoculated on Bowman leaves. The ∆Csslt2 mutants produced more vegetative hyphae, had lighter pigmentation, were more sensitive to cell wall degrading enzymes, and were reduced in virulence on Bowman leaves, although they formed normal appressoria like the wild type. Root infection assays indicated that the ∆Cshog1 and ∆Csslt2 mutants were able to infect barley roots while the ∆Csfus3 and ∆Csste11 failed to cause any symptoms. However, no significant difference in virulence was observed for ∆Cshog1 mutants while ∆Csslt2 mutants showed significantly reduced virulence on barley roots in comparison with the wild type. Our results indicated that all of these MAPK and MAPKKK genes are involved in the regulation of fungal

  10. Effects of Terminalia bellerica Roxb. methanolic extract on mouse immune response in vitro

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    Aurasorn Saraphanchotiwitthaya1

    2008-06-01

    Full Text Available In this study, the effects of Terminalia bellerica methanolic extract (0.1, 1, 10, 100 and 500 g/ml on the mouse immune system were investigated in vitro. Phagocytic activity and lymphocyte proliferation were assayed. The results indicated the effect of the extract (500 g/ml on the stimulation of macrophage phagocytosis, through the production of superoxide anions and acid phosphatase, with a phagocytic index (PI value of approximately 1.5 and 1.3, respectively. For the lymphocyte proliferation assay, the extract (500 g/ml with phytohemagglutinin exhibited maximal activation, with a stimulation index (SI value of approximately 5.8. With concanavalin A, lipopolysaccharide, and pokeweed mitogen, similar activation (SI 4.5 of lymphocyte proliferation was observed. However, at low concentrations (0.1 g/ml, T. bellerica extract with concanavalin A and pokeweed mitogen caused suppressant activity (SI 0.7. The results suggested that the effect of extract on T-lymphocyte proliferation occurred through the same mechanism as phytohemagglutinin, concanavalin A and B-lymphocyte proliferation through T-cell independent and T-cell dependent mechanisms, in manners similar to lipopolysaccharide and pokeweed mitogen respectively. It might be concluded that the methanolic extract of T. bellerica affected the mouse immune system, specifically both the cellular and humoral immune response in vitro, corresponding with its folklore applications. These results can be further applied to the treatment of human immune mediated diseases.

  11. Increased susceptibility of peripheral blood mononuclear cells to equine herpes virus type 1 infection upon mitogen stimulation: a role of the cell cycle and of cell-to-cell transmission of the virus.

    Science.gov (United States)

    van der Meulen, Karen M; Nauwynck, Hans J; Pensaert, Maurice B

    2002-04-22

    Equine herpesvirus-1 (EHV-1) is an important pathogen of horses, causing abortion and nervous system disorders, even in vaccinated animals. During the cell-associated viremia, EHV-1 is carried by peripheral blood mononuclear cells (PBMC), mainly lymphocytes. In vitro, monocytes are the most important fraction of PBMC in which EHV-1 replicates, however, mitogen stimulation prior to EHV-1 infection increases the percentage of infected lymphocytes. The role of the cell cycle in viral replication and the role of cluster formation in cell-to-cell transmission of the virus were examined in mitogen-stimulated PBMC. Involvement of the cell cycle was examined by stimulating PBMC with ionomycin/phorbol dibutyrate (IONO/PDB) during 0, 12, 24 and 36 h prior to inoculation. Cell cycle distribution at the moment of inoculation and the percentage of EHV-1 antigen-positive PBMC at 0, 12 and 24 hours post inoculation (hpi) were determined by flow cytometry and immunofluorescence microscopy, respectively. The role of clusters was examined by immunofluorescence staining within clusters of stimulated PBMC using antibodies against EHV-1. Significant correlations were found between the increase of cells in the S- or G2/M-phase after a certain time interval of prestimulation and the increase of EHV-1 antigen-positive cells. The percentage of clusters with adjacent infected cells significantly increased from 3.3% at 8 hpi to 23.7% at 24 hpi and the maximal number of adjacent infected cells increased from 2 to 7. Addition of anti-EHV-1 hyperimmune serum did not significantly alter these percentages. Mitogen stimulation favours EHV-1 infection in PBMC by: (i) initiating cell proliferation and (ii) inducing formation of clusters, thereby facilitating direct cell-associated transmission of virus.

  12. Anti-inflammatory effects of cordycepin in lipopolysaccharide-stimulated RAW 264.7 macrophages through Toll-like receptor 4-mediated suppression of mitogen-activated protein kinases and NF-κB signaling pathways

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    Choi YH

    2014-10-01

    Full Text Available Yung Hyun Choi,1,2 Gi-Young Kim,3 Hye Hyeon Lee4 1Department of Biochemistry, Dongeui University College of Korean Medicine, Busan, 2Anti-Aging Research Center and Blue-Bio Industry RIC, Dongeui University, Busan, 3Laboratory of Immunobiology, Department of Marine Life Sciences, Jeju National University, Jeju, 4Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea Abstract: Cordycepin is the main functional component of the Cordyceps species, which has been widely used in traditional Oriental medicine. This compound possesses many pharmacological properties, such as an ability to enhance immune function, as well as antioxidant, antiaging, and anticancer effects. In the present study, we investigated the anti-inflammatory effects of cordycepin using a murine macrophage RAW 264.7 cell model. Our data demonstrated that cordycepin suppressed production of proinflammatory mediators such as nitric oxide (NO and prostaglandin E2 by inhibiting inducible NO synthase and cyclooxygenase-2 gene expression. Cordycepin also inhibited the release of proinflammatory cytokines, including tumor necrosis factor-alpha and interleukin-1-beta, through downregulation of respective mRNA expression. In addition, pretreatment with cordycepin significantly inhibited lipopolysaccharide (LPS-induced phosphorylation of mitogen-activating protein kinases and attenuated nuclear translocation of NF-κB by LPS, which was associated with abrogation of inhibitor kappa B-alpha degradation. Furthermore, cordycepin potently inhibited the binding of LPS to macrophages and LPS-induced Toll-like receptor 4 and myeloid differentiation factor 88 expression. Taken together, the results suggest that the inhibitory effects of cordycepin on LPS-stimulated inflammatory responses in RAW 264.7 macrophages are associated with suppression of mitogen-activating protein kinases and activation of NF-κB by inhibition of the Toll-like receptor 4 signaling pathway. Keywords

  13. Expression profiles of the immune genes CD4, CD8β, IFNγ, IL-4, IL-6 and IL-10 in mitogen-stimulated koala lymphocytes (Phascolarctos cinereus by qRT-PCR

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    Iona E. Maher

    2014-03-01

    Full Text Available Investigation of the immune response of the koala (Phascolarctos cinereus is needed urgently, but has been limited by scarcity of species-specific reagents and methods for this unique and divergent marsupial. Infectious disease is an important threat to wild populations of koalas; the most widespread and important of these is Chlamydial disease, caused by Chlamydia pecorum and Chlamydia pneumoniae. In addition, koala retrovirus (KoRV, which is of 100% prevalence in northern Australia, has been proposed as an important agent of immune suppression that could explain the koala’s susceptibility to disease. The correct balance of T regulatory, T helper 1 (Th1 and Th2 lymphocyte responses are important to an individual’s susceptibility or resistance to chlamydial infection. The ability to study chlamydial or KoRV pathogenesis, effects of environmental stressors on immunity, and the response of koalas to vaccines under development, by examining the koala’s adaptive response to natural infection or in-vitro stimulation, has been limited to date by a paucity of species- specific reagents. In this study we have used cytokine sequences from four marsupial genomes to identify mRNA sequences for key T regulatory, Th1 and Th2 cytokines interleukin 4 (IL-4, interleukin 6 (IL-6, interleukin 10 (IL-10 and interferon gamma (IFNγ along with CD4 and CD8β. The koala sequences used for primer design showed >58% homology with grey short-tailed opossum, >71% with tammar wallaby and 78% with Tasmanian devil amino acid sequences. We report the development of real-time RT-PCR assays to measure the expression of these genes in unstimulated cells and after three common mitogen stimulation protocols (phorbol myristate acetate/ionomycin, phorbol myristate acetate/phytohemagglutinin and concanavalin A. Phorbol myristate acetate/ionomycin was found to be the most effective mitogen to up-regulate the production of IL-4, IL-10 and IFNγ. IL-6 production was not

  14. Improvement in neurological outcome and abolition of cerebrovascular endothelin B and 5-hydroxytryptamine 1B receptor upregulation through mitogen-activated protein kinase kinase 1/2 inhibition after subarachnoid hemorrhage in rats

    DEFF Research Database (Denmark)

    Larsen, Carl Christian; Povlsen, Gro Klitgaard; Rasmussen, Marianne Nelly Paola

    2011-01-01

    (B)) and 5-hydroxytryptamine 1B (5-HT(1B)) receptors has been demonstrated in cerebral artery smooth muscles in the delayed ischemic phase after experimental SAH, and intracellular signaling via the mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase 1/2 pathway has been shown...... to be involved in this upregulation. The aim in the present study was to determine whether treatment with the MEK1/2 inhibitor U0126 can prevent cerebrovascular receptor upregulation and improve functional outcome after experimental SAH in rats....

  15. Rapid, sequential activation of mitogen-activated protein kinases and transcription factors precedes proinflammatory cytokine mRNA expression in spleens of mice exposed to the trichothecene vomitoxin.

    Science.gov (United States)

    Zhou, Hui-Ren; Islam, Zahidul; Pestka, James J

    2003-03-01

    Since proinflammatory cytokine mRNA expression is induced within lymphoid tissue in vivo by the trichothecene vomitoxin (VT) in a rapid (1-2 h) and transient (4-8 h) fashion, it was hypothesized that mitogen-activated protein kinases (MAPKs) and transcription factors associated upstream with gene transcription of these cytokines are activated prior to or within these time windows. To test this hypothesis, mice were first treated with a single oral dose of VT and then analyzed for MAPK phosphorylation in the spleen. As little as 1 mg/kg of VT induced JNK 1/2, ERK 1/2, and p38 phosphorylation with maximal effects being observed at 5 to 100 mg/kg of VT. VT transiently induced JNK and p38 phosphorylation over a 60-min time period with peak effects being observed at 15 and 30 min, respectively. In contrast, ERK remained phosphorylated from 15 to 120 min. Next, the binding of activating protein 1 (AP-1), CCAAT enhancer-binding protein (C/EBP), CRE-binding protein (CREB), and nuclear factor-kappaB (NF-kappaB) was measured by electrophoretic mobility shift assay (EMSA) using four different consensus transcriptional control motifs at 0, 0.5, 1.5, 4, and 8 h after oral exposure to 25 mg/kg of VT. AP-1 binding activity was differentially elevated from 0.5 h to 8 h, whereas C/EBP binding was elevated only at 0.5 h. CREB binding decreased slightly at 0.5 h but gradually increased, reaching a maximum at 4 h. NF-kappaB binding was increased only slightly at 4 and 8 h. The specificities of AP-1, C/EBP, CREB, and NF-kappaB for relevant DNA motifs were verified by competition assays, using an excess of unlabeled consensus and mutant oligonucleotides. Supershift EMSAs and Western blot analysis identified specific VT-inducible DNA binding proteins for AP-1 (cJun, phospho c-jun, JunB, and JunD), C/EBP (C/EBPbeta), CREB (CREB-1 and ATF-2), and NF-kappaB (p50 and cRel). Finally, when the effects of oral VT exposure on proinflammatory gene expression were assessed at 3, 6, and 9 h

  16. Cytotoxicity and mitogenicity assays with real-time and label-free monitoring of human granulosa cells with an impedance-based signal processing technology intergrating micro-electronics and cell biology.

    Science.gov (United States)

    Oktem, Ozgur; Bildik, Gamze; Senbabaoglu, Filiz; Lack, Nathan A; Akin, Nazli; Yakar, Feridun; Urman, Defne; Guzel, Yilmaz; Balaban, Basak; Iwase, Akira; Urman, Bulent

    2016-04-01

    A recently developed technology (xCelligence) integrating micro-electronics and cell biology allows real-time, uninterrupted and quantitative analysis of cell proliferation, viability and cytotoxicity by measuring the electrical impedance of the cell population in the wells without using any labeling agent. In this study we investigated if this system is a suitable model to analyze the effects of mitogenic (FSH) and cytotoxic (chemotherapy) agents with different toxicity profiles on human granulosa cells in comparison to conventional methods of assessing cell viability, DNA damage, apoptosis and steroidogenesis. The system generated the real-time growth curves of the cells, and determined their doubling times, mean cell indices and generated dose-response curves after exposure to cytotoxic and mitogenic stimuli. It accurately predicted the gonadotoxicity of the drugs and distinguished less toxic agents (5-FU and paclitaxel) from more toxic ones (cisplatin and cyclophosphamide). This platform can be a useful tool for specific end-point assays in reproductive toxicology. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. ZmMKK1, a novel group A mitogen-activated protein kinase kinase gene in maize, conferred chilling stress tolerance and was involved in pathogen defense in transgenic tobacco.

    Science.gov (United States)

    Cai, Guohua; Wang, Guodong; Wang, Li; Pan, Jiaowen; Liu, Yang; Li, Dequan

    2014-01-01

    As an important intracellular signaling module, the mitogen-activated protein kinase (MAPK) cascades have been previously implicated in signal transduction during plants responsing to various environmental stresses as well as pathogen attack. The mitogen-activated protein kinase kinase acts as the convergent point of MAPK cascades during a variety of stress signaling. In this study, a novel MAPKK gene, ZmMKK1, in maize (Zea mays L.) belonging to group A MAPKK was isolated and functionally characterized. ZmMKK1 was mainly localized in the cytoplasm and its constitutive kinase-active form ZmMKK1DD was localized in both cytoplasm and nucleus. QRT-PCR analysis uncovered that ZmMKK1 expression was triggered by abiotic and biotic stresses and exogenous signaling molecules. Moreover, hydrogen peroxide (H2O2) and Ca(2+) mediated 12°C-induced up-regulated expressing of ZmMKK1 at mRNA level. Ectopic expression of ZmMKK1 in tobacco (Nicotiana tabacum) conferred tolerance to chilling stress by higher antioxidant enzyme activities, more accumulation of osmoregulatory substances and more significantly up-expression of ROS-related and stress-responsive genes compared with empty vector control plants. Furthermore, ZmMKK1 played differential functions in biotrophic versus necrotrophic pathogen-induced responses. These results suggested ZmMKK1 played a crucial role in chilling stress and pathogen defense in plants. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  18. The elephant interferon gamma assay: a contribution to diagnosis of tuberculosis in elephants.

    Science.gov (United States)

    Angkawanish, T; Morar, D; van Kooten, P; Bontekoning, I; Schreuder, J; Maas, M; Wajjwalku, W; Sirimalaisuwan, A; Michel, A; Tijhaar, E; Rutten, V

    2013-11-01

    Mycobacterium tuberculosis (M. tb) has been shown to be the main causative agent of tuberculosis in elephants worldwide. M. tb may be transmitted from infected humans to other species including elephants and vice versa, in case of prolonged intensive contact. An accurate diagnostic approach covering all phases of the infection in elephants is required. As M. tb is an intracellular pathogen and cell-mediated immune (CMI) responses are elicited early after infection, the skin test is the CMI assay of choice in humans and cattle. However, this test is not applicable in elephants. The interferon gamma (IFN-γ) assay is considered a good alternative for the skin test in general, validated for use in cattle and humans. This study was aimed at development of an IFN-γ assay applicable for diagnosis of tuberculosis in elephants. Recombinant elephant IFN-γ (rEpIFN-γ) produced in eukaryotic cells was used to immunize mice and generate the monoclonal antibodies. Hybridomas were screened for IFN-γ-specific monoclonal antibody production and subcloned, and antibodies were isotyped and affinity purified. Western blot confirmed recognition of the rEpIFN-γ. The optimal combination of capture and detection antibodies selected was able to detect rEpIFN-γ in concentrations as low as 1 pg/ml. The assay was shown to be able to detect the native elephant IFN-γ, elicited in positive-control cultures (pokeweed mitogen (PWM), phorbol myristate acetate plus ionomycin (PMA/I)) of both Asian and African elephant whole-blood cultures (WBC). Preliminary data were generated using WBC from non-infected elephants, a M. tb infection-suspected elephant and a culture-confirmed M. tb-infected elephant. The latter showed measurable production of IFN-γ after stimulation with ESAT6/CFP10 PPDB and PPDA in concentration ranges as elicited in WBC by Mycobacterium tuberculosis complex (MTBC)-specific antigens in other species. Hence, the IFN-γ assay presented potential as a diagnostic tool for the

  19. Phloretin induces apoptosis in H-Ras MCF10A human breast tumor cells through the activation of p53 via JNK and p38 mitogen-activated protein kinase signaling.

    Science.gov (United States)

    Kim, Mi-Sung; Kwon, Jung Yeon; Kang, Nam Joo; Lee, Ki Won; Lee, Hyong Joo

    2009-08-01

    Mutations in Ras play a critical role in the development of human cancers, including breast cancer. We investigated the possible antiproliferative effects of the naturally occurring dihydrochalcone phloretin [2',4',6'-trihydroxy-3-(4-hydroxyphenyl)-propiophenone] on H-Ras-transformed MCF10A human breast epithelial (H-Ras MCF10A) cells. Phloretin suppressed H-Ras MCF10A cell proliferation in a dose-dependent manner and induced nuclear condensation in the cells, indicating that phloretin-induced cell death occurs mainly via the induction of apoptosis. Prominent upregulation of p53 and Bax and cleavage of poly (ADP)-ribose polymerase were also detected in the phloretin-treated cells. Finally, phloretin markedly increased caspase-3 activity as well as JNK and p38 mitogen-activated protein kinase signaling. Our findings suggest that the phloretin-induced apoptosis of breast tumor cells contributes to the chemopreventive potential of phloretin against breast cancer.

  20. Induction of viral, 7-methyl-guanosine cap-independent translation and oncolysis by mitogen-activated protein kinase-interacting kinase-mediated effects on the serine/arginine-rich protein kinase.

    Science.gov (United States)

    Brown, Michael C; Bryant, Jeffrey D; Dobrikova, Elena Y; Shveygert, Mayya; Bradrick, Shelton S; Chandramohan, Vidyalakshmi; Bigner, Darell D; Gromeier, Matthias

    2014-11-01

    Protein synthesis, the most energy-consuming process in cells, responds to changing physiologic priorities, e.g., upon mitogen- or stress-induced adaptations signaled through the mitogen-activated protein kinases (MAPKs). The prevailing status of protein synthesis machinery is a viral pathogenesis factor, particularly for plus-strand RNA viruses, where immediate translation of incoming viral RNAs shapes host-virus interactions. In this study, we unraveled signaling pathways centered on the ERK1/2 and p38α MAPK-interacting kinases MNK1/2 and their role in controlling 7-methyl-guanosine (m(7)G) "cap"-independent translation at enterovirus type 1 internal ribosomal entry sites (IRESs). Activation of Raf-MEK-ERK1/2 signals induced viral IRES-mediated translation in a manner dependent on MNK1/2. This effect was not due to MNK's known functions as eukaryotic initiation factor (eIF) 4G binding partner or eIF4E(S209) kinase. Rather, MNK catalytic activity enabled viral IRES-mediated translation/host cell cytotoxicity through negative regulation of the Ser/Arg (SR)-rich protein kinase (SRPK). Our investigations suggest that SRPK activity is a major determinant of type 1 IRES competency, host cell cytotoxicity, and viral proliferation in infected cells. We are targeting unfettered enterovirus IRES activity in cancer with PVSRIPO, the type 1 live-attenuated poliovirus (PV) (Sabin) vaccine containing a human rhinovirus type 2 (HRV2) IRES. A phase I clinical trial of PVSRIPO with intratumoral inoculation in patients with recurrent glioblastoma (GBM) is showing early promise. Viral translation proficiency in infected GBM cells is a core requirement for the antineoplastic efficacy of PVSRIPO. Therefore, it is critically important to understand the mechanisms controlling viral cap-independent translation in infected host cells. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Selective involvement of ERK and JNK mitogen-activated protein kinases in early rheumatoid arthritis (1987 ACR criteria compared to 2010 ACR/EULAR criteria): a prospective study aimed at identification of diagnostic and prognostic biomarkers as well as therapeutic targets

    NARCIS (Netherlands)

    de Launay, Daphne; van de Sande, Marleen G. H.; de Hair, Maria J. H.; Grabiec, Aleksander M.; van de Sande, Gijs P. M.; Lehmann, K. Aad; Wijbrandts, Carla A.; van Baarsen, Lisa G. M.; Gerlag, Danielle M.; Tak, Paul P.; Reedquist, Kris A.

    2012-01-01

    Objectives To investigate the expression and activation of mitogen-activated protein kinases in patients with early arthritis who are disease-modifying antirheumatic drug (DMARD) naive. Methods A total of 50 patients with early arthritis who were DMARD naive (disease duration <1 year) were

  2. Pro-life role for c-Jun N-terminal kinase and p38 mitogen-activated protein kinase at rostral ventrolateral medulla in experimental brain stem death.

    Science.gov (United States)

    Chang, Alice Y W

    2012-11-17

    Based on an experimental brain stem death model, we demonstrated previously that activation of the mitogen-activated protein kinase kinase 1/2 (MEK1/2)/extracellular signal-regulated kinase 1/2 (ERK1/2)/ mitogen-activated protein kinase signal-interacting kinase 1/2 (MNK1/2) cascade plays a pro-life role in the rostral ventrolateral medulla (RVLM), the origin of a life-and-death signal detected from systemic arterial pressure, which sequentially increases (pro-life) and decreases (pro-death) to reflect progressive dysfunction of central cardiovascular regulation during the advancement towards brain stem death in critically ill patients. The present study assessed the hypothesis that, in addition to ERK1/2, c-Jun NH2-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK), the other two mammalian members of MAPKs that are originally identified as stress-activated protein kinases, are activated specifically by MAPK kinase 4 (MAP2K4) or MAP2K6 and play a pro-life role in RVLM during experimental brain stem death. We further delineated the participation of phosphorylating activating transcriptional factor-2 (ATF-2) and c-Jun, the classical transcription factor activated by JNK or p38MAPK, in this process. An experimental model of brain stem death that employed microinjection of the organophosphate insecticide mevinphos (Mev; 10 nmol) bilaterally into RVLM of Sprague-Dawley rats was used, alongside cardiovascular, pharmacological and biochemical evaluations. Results from ELISA showed that whereas the total JNK, p38MAPK, MAP2K4 and MAP2K6 were not affected, augmented phosphorylation of JNK at Thr183 and Tyr185 and p38MAPK at Thr180 and Tyr182, accompanied by phosphorylation of their upstream activators MAP2K4 at Ser257 and Thr261 and MAP2K6 at Ser207 and Thr211 in RVLM occurred preferentially during the pro-life phase of experimental brain stem death. Moreover, the activity of transcription factors ATF-2 at Thr71 and c-Jun at Ser73, rather than Elk-1 at

  3. Short communication: Camel milk ameliorates inflammatory responses and oxidative stress and downregulates mitogen-activated protein kinase signaling pathways in lipopolysaccharide-induced acute respiratory distress syndrome in rats.

    Science.gov (United States)

    Zhu, Wei-Wei; Kong, Gui-Qing; Ma, Ming-Ming; Li, Yan; Huang, Xiao; Wang, Li-Peng; Peng, Zhen-Yi; Zhang, Xiao-Hua; Liu, Xiang-Yong; Wang, Xiao-Zhi

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is a complex syndrome disorder with high mortality rate. Camel milk (CM) contains antiinflammatory and antioxidant properties and protects against numerous diseases. This study aimed to demonstrate the function of CM in lipopolysaccharide (LPS)-induced ARDS in rats. Camel milk reduced the lung wet:dry weight ratio and significantly reduced LPS-induced increases in neutrophil infiltration, interstitial and intra-alveolar edema, thickness of the alveolar wall, and lung injury scores of lung tissues. It also had antiinflammatory and antioxidant effects on LPS-induced ARDS. After LPS stimulation, the levels of proinflammatory cytokines (tumor necrosis factor-α, IL-10, and IL-1β) in serum and oxidative stress markers (malondialdehyde, myeloperoxidase, and total antioxidant capacity) in lung tissue were notably attenuated by CM. Camel milk also downregulated mitogen-activated protein kinase signaling pathways. Given these results, CM is a potential complementary food for ARDS treatment. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  4. Effects of the activated mitogen-activated protein kinase pathway via the c-ros receptor tyrosine kinase on the T47D breast cancer cell line following alcohol exposure.

    Science.gov (United States)

    Lee, Hyung Tae; Kim, Se Kye; Choi, Mi Ran; Park, Ji Hyun; Jung, Kyoung Hwa; Chai, Young Gyu

    2013-03-01

    Compared to other cancers affecting women, breast cancer is significantly associated with alcohol consumption. However, the principles underlying the carcinogenesis of alcohol-induced breast cancer and the related metastatic mechanisms have yet to be established. To observe the effect of alcohol on the growth regulation in breast cancer cells, we identified differentially expressed proteins in alcohol-exposed human breast cancer T47D cells using gel-based proteomics analysis. The expression of c-ros receptor tyrosine kinase (ROS1) was increased and activated by autophosphorylation, thereby activating mitogen- and stress-activated protein kinase 1 (MSK1) through the mitogen‑activated protein kinase (MAPK) pathway; activated MSK1, in turn, phosphorylated histone 3 serine 10 (H3S10p) residues in the nucleus. The increase in H3S10 phosphorylation consequently increased the level of expression of immediate-early gene such as c-fos. This study demonstrated that when breast cancer cells are exposed to alcohol, phosphorylated ROS1 activates MSK1 via Erk1/2 in the MAPK pathway, which then induces modifications to histone residues that regulate gene expression by 14-3-3 protein recruitment, leading to a lack of control of breast cancer cell proliferation.

  5. Ligustrazine attenuates the platelet-derived growth factor-BB-induced proliferation and migration of vascular smooth muscle cells by interrupting extracellular signal-regulated kinase and P38 mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yu, Lifei; Huang, Xiaojing; Huang, Kai; Gui, Chun; Huang, Qiaojuan; Wei, Bin

    2015-07-01

    The abnormal proliferation and migration of vascular smooth muscle cells (VSMCs) leads to intimal thickening of the aorta and is, therefore, important in the development of arteriosclerosis. As a result, the use of antiproliferative and antimigratory agents for VSMCs offers promise for the treatment of vascular disorders. Although several studies have demonstrated that ligustrazine may be used to treat heart and blood vessel diseases, the detailed mechanism underlying its actions remain to be elucidated. In the present study, the inhibitory effect of ligustrazine on platelet-derived growth factor (PDGF)-BB-stimulated VSMC proliferation and migration, and the underlying mechanisms were investigated. The findings demonstrated that ligustrazine significantly inhibited PDGF-BB-stimulated VSMC proliferation. VSMCs dedifferentiated into a proliferative phenotype under PDGF-BB stimulation, which was effectively reversed by the administration of ligustrazine. In addition, ligustrazine also downregulated the production of nitric oxide and cyclic guanine monophosphate, induced by PDGF-BB. Additionally, ligustrazine significantly inhibited PDGF-BB-stimulated VSMC migration. Mechanistic investigation indicated that the upregulation of cell cycle-associated proteins and the activation of the extracellular signal-regulated kinase (ERK) and P38 mitogen-activated protein kinase (MAPK) signaling induced by PDGF-BB was suppressed by the administration of ligustrazine. In conclusion, the present study, demonstrated for the first time, to the best of our knowledge, that ligustrazine downregulated PDGF-BB-induced VSMC proliferation and migration partly, at least, through inhibiting the activation of the ERK and P38 MAPK signaling.

  6. p38 mitogen-activated protein kinase (p38MAPK) upregulates catalase levels in response to low dose H2O2 treatment through enhancement of mRNA stability.

    Science.gov (United States)

    Sen, Prosenjit; Chakraborty, Prabir Kumar; Raha, Sanghamitra

    2005-08-15

    V79 fibroblasts were repetitively stressed through multiple exposures to a low dose (30 microM) H2O2 in culture for 4 weeks. Catalase activity, protein levels and mRNA levels increased markedly (5-6-fold) during this time and these augmentations were inhibited by the simultaneous presence of SB203580, an inhibitor of p38 mitogen-activated protein kinase (p38MAPK). p38MAPK became dually phosphorylated and ATF-2, a p38MAPK substrate also became increasingly phosphorylated over the repetitive stress period. Short interfering RNA that induced effective silencing of p38MAPK, was used to silence p38MAPK in V79 fibroblasts. Silencing of p38MAPK drastically hindered the elevation in catalase (protein and mRNA) levels observed after a single low dose (50 microM) of H2O. The rise in catalase mRNA levels induced by low concentration (single and multiple dose) H2O2 treatment was established to be unconnected with transcriptional upregulation but was brought forth primarily by an enhancement in catalase mRNA stability through the action of p38MAPK. Therefore, our data strongly indicate that activation of p38MAPK is a key controlling step in the upregulation of catalase levels by low dose H2O2 treatment.

  7. RNA interference-based (RNAi) suppression of AtMPK6, an Arabidopsis mitogen-activated protein kinase, results in hypersensitivity to ozone and misregulation of AtMPK3

    International Nuclear Information System (INIS)

    Miles, Godfrey P.; Samuel, Marcus A.; Zhang Yuelin; Ellis, Brian E.

    2005-01-01

    The recent increase in tropospheric ozone (O 3 ) concentrations promotes additional oxidative stress through the production of reactive oxygen species (ROS) in plant tissues, resulting in the activation of genes whose products enable the stressed cells to retain their integrity and function. This response is made possible by an integration of highly regulated signaling networks that mediate the perception of, and response to, this oxidative assault. In Arabidopsis thaliana, ROS-induced signaling has been shown to flow through a protein phosphorylation cascade involving the mitogen-activated protein kinases (MAPKs) AtMPK3 (MPK3) and AtMPK6 (MPK6). We found that RNAi-mediated silencing of MPK6 renders the plant more sensitive to ozone, as determined by visible leaf damage. The MPK6-RNAi genotype also displayed a more intense and prolonged activation of MPK3 compared to that of WT plants. An MPK3 loss-of-function genotype is similarly very sensitive to ozone, and displays an abnormally prolonged MPK6 activation profile, suggesting reciprocity in regulation between these two MAPKs. - MPK6 is pivotal in the overall response to oxidative stress and regulation of MPK3 in Arabidopsis thaliana

  8. AMP N1-Oxide, a Unique Compound of Royal Jelly, Induces Neurite Outgrowth from PC12 Vells via Signaling by Protein Kinase A Independent of that by Mitogen-Activated Protein Kinase

    Directory of Open Access Journals (Sweden)

    Noriko Hattori

    2010-01-01

    Full Text Available Earlier we identified adenosine monophosphate (AMP N1-oxide as a unique compound of royal jelly (RJ that induces neurite outgrowth (neuritegenesis from cultured rat pheochromocytoma PC12 cells via the adenosine A2A receptor. Now, we found that AMP N1-oxide stimulated the phosphorylation of not only mitogen-activated protein kinase (MAPK but also that of cAMP/calcium-response element-binding protein (CREB in a dose-dependent manner. Inhibition of MAPK activation by a MEK inhibitor, PD98059, did not influence the AMP N1-oxide-induced neuritegenesis, whereas that of protein kinase A (PKA by a selective inhibitor, KT5720, significantly reduced neurite outgrowth. AMP N1-oxide also had the activity of suppressing the growth of PC12 cells, which correlated well with the neurite outgrowth-promoting activity. KT5720 restored the growth of AMP N1-oxide-treated PC12 cells. It is well known that nerve growth factor suppresses proliferation of PC12 cells before causing stimulation of neuronal differentiation. Thus, AMP N1-oxide elicited neuronal differentiation of PC12 cells, as evidenced by generation of neurites, and inhibited cell growth through adenosine A2A receptor-mediated PKA signaling, which may be responsible for characteristic actions of RJ.

  9. Lipoxin A4 regulates expression of the estrogen receptor and inhibits 17β-estradiol induced p38 mitogen-activated protein kinase phosphorylation in human endometriotic stromal cells.

    Science.gov (United States)

    Chen, Shuo; Wu, Rong-Feng; Su, Lin; Zhou, Wei-Dong; Zhu, Mao-Bi; Chen, Qiong-Hua

    2014-07-01

    To study the role of lipoxin A4 (LXA4) in endometriosis. Molecular analysis in human samples and primary human endometriotic stromal cells (ESCs). University hospital. Forty-nine premenopausal women (30 patients with endometriosis and 19 controls). Normal and ectopic endometrial biopsies obtained during surgery performed during the proliferative phase of the menstrual cycle; ESCs used for in vitro studies. Levels of LXA4 measured by enzyme-linked immunosorbent assay (ELISA); mRNA levels of the estrogen receptor (ER), progestogen receptor (PR), tumor necrosis factor α (TNF-α), and interleukin 6 (IL-6) quantified by quantitative reverse-transcription polymerase chain reaction (qRT-PCR); and p38 mitogen-activated protein kinase (p38 MAPK) phosphorylation evaluated by Western blotting. The LXA4 expression level decreased in ectopic tissue as well as ERα and PR, although the expression of ERβ increased in ectopic endometrium compared with the controls. Investigations with correlation analysis revealed the expression of LXA4 was positively correlated with ERα and negatively correlated with ERβ in vivo. Moreover, administering LXA4 could augment ERβ expression in ESCs and inhibit the 17β-estradiol-induced phosphorylation of p38 MAPK very likely through ERβ. Our findings indicate that LXA4 regulates ERβ expression and inhibits 17β-estradiol-induced phosphorylation of p38 MAPK, very likely through ERβ in ESCs. Copyright © 2014. Published by Elsevier Inc.

  10. Effects of inhibitors of vascular endothelial growth factor receptor 2 and downstream pathways of receptor tyrosine kinases involving phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin or mitogen-activated protein kinase in canine hemangiosarcoma cell lines.

    Science.gov (United States)

    Adachi, Mami; Hoshino, Yuki; Izumi, Yusuke; Sakai, Hiroki; Takagi, Satoshi

    2016-07-01

    Canine hemangiosarcoma (HSA) is a progressive malignant neoplasm with no current effective treatment. Previous studies showed that receptor tyrosine kinases and molecules within their downstream pathways involving phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (m-TOR) or mitogen-activated protein kinase (MAPK) were overexpressed in canine, human, and murine tumors, including HSA. The present study investigated the effects of inhibitors of these pathways in canine splenic and hepatic HSA cell lines using assays of cell viability and apoptosis. Inhibitors of the MAPK pathway did not affect canine HSA cell viability. However, cell viability was significantly reduced by exposure to inhibitors of vascular endothelial growth factor receptor 2 and the PI3K/Akt/m-TOR pathway; these inhibitors also induced apoptosis in these cell lines. These results suggest that these inhibitors reduce the proliferation of canine HSA cells by inducing apoptosis. Further study of these inhibitors, using xenograft mouse models of canine HSA, are warranted to explore their potential for clinical application.

  11. “Three Methods and Three Points” regulates p38 mitogen-activated protein kinase in the dorsal horn of the spinal cord in a rat model of sciatic nerve injury

    Directory of Open Access Journals (Sweden)

    Xin Guo

    2016-01-01

    Full Text Available Tuina is a traditional Chinese treatment for sensory disturbances caused by peripheral nerve injury and related diseases. Our previous studies showed that tuina regulates relevant regions and indices of the spinal dorsal horn using the Dian, Bo, and Rou method in Yinmen (BL37, Yanglingquan (GB34, and Weizhong (BL40. Treatment prevents muscle atrophy, protects spinal cord neurons, and promotes sciatic nerve repair. The mechanisms of action of tuina for treating peripheral nerve injury remain poorly understood. This study established rat models of sciatic nerve injury using the crushing method. Rats received Chinese tuina in accordance with the principle of “Three Methods and Three Points,” once daily for 20 days. Tuina intervention reduced paw withdrawal latency and improved wet weight of the gastrocnemius muscle, as well as promoting morphological recovery of sciatic nerve fibers, Schwann cells, and axons. The protein expression levels of phospho-p38 mitogen-activated protein kinase, tumor necrosis factor-α, and interleukin-1β also decreased. These findings indicate that “Three Methods and Three Points” promoted morphological recovery and improved behavior of rats with peripheral nerve injury.

  12. The Histone Deacetylase Inhibitors MS-275 and SAHA Suppress the p38 Mitogen-Activated Protein Kinase Signaling Pathway and Chemotaxis in Rheumatoid Arthritic Synovial Fibroblastic E11 Cells

    Directory of Open Access Journals (Sweden)

    Hai-Shu Lin

    2013-11-01

    Full Text Available MS-275 (entinostat and SAHA (vorinostat, two histone deacetylase (HDAC inhibitors currently in oncological trials, have displayed potent anti-rheumatic activities in rodent models of rheumatoid arthritis (RA. To further elucidate their anti-inflammatory mechanisms, the impact of MS-275 and SAHA on the p38 mitogen-activated protein kinase (MAPK signaling pathway and chemotaxis was assessed in human rheumatoid arthritic synovial fibroblastic E11 cells. MS-275 and SAHA significantly suppressed the expression of p38α  MAPK, but induced the expression of MAPK phosphatase-1 (MKP-1, an endogenous suppressor of p38α  in E11 cells. At the same time, the association between p38α and MKP-1 was up-regulated and consequently, the activation (phosphorylation of p38α  was inhibited. Moreover, MS-275 and SAHA suppressed granulocyte chemotactic protein-2 (GCP-2, monocyte chemotactic protein-2 (MCP-2 and macrophage migration inhibitory factor (MIF in E11 cells in a concentration-dependent manner. Subsequently, E11-driven migration of THP-1 and U937 monocytes was inhibited. In summary, suppression of the p38 MAPK signaling pathway and chemotaxis appear to be important anti-rheumatic mechanisms of action of these HDAC inhibitors.

  13. Research on Parallel Three Phase PWM Converters base on RTDS

    Science.gov (United States)

    Xia, Yan; Zou, Jianxiao; Li, Kai; Liu, Jingbo; Tian, Jun

    2018-01-01

    Converters parallel operation can increase capacity of the system, but it may lead to potential zero-sequence circulating current, so the control of circulating current was an important goal in the design of parallel inverters. In this paper, the Real Time Digital Simulator (RTDS) is used to model the converters parallel system in real time and study the circulating current restraining. The equivalent model of two parallel converters and zero-sequence circulating current(ZSCC) were established and analyzed, then a strategy using variable zero vector control was proposed to suppress the circulating current. For two parallel modular converters, hardware-in-the-loop(HIL) study based on RTDS and practical experiment were implemented, results prove that the proposed control strategy is feasible and effective.

  14. Comparison of Simple Self-Oscillating PWM Modulators

    DEFF Research Database (Denmark)

    Dahl, Nicolai J.; Iversen, Niels Elkjær; Knott, Arnold

    2016-01-01

    Switch-mode power amplifiers has become the conventional choice for audio applications due to their superior efficiency and excellent audio performance. These amplifiers rely on high frequency modulation of the audio input. Conventional modulators use a fixed high frequency for modulation. Self......-oscillating modulators do not have a fixed modulation frequency and can provide good audio performance with very simple circuitry. This paper proposes a new type of self-oscillating modulator. The proposed modulator is compared to an already existing modulator of similar type and their performances are compared both...... theoretically and experimentally. The result shows that the proposed modulator provides a higher degree of linearity resulting in around 2% lower Total Harmonic Distortion (THD)....

  15. Flash Welding Control by Use of PWM Inverter Power Supply

    Science.gov (United States)

    Nagura, Kouki; Sato, Yukihiko; Yamamura, Naoki; Ishida, Muneaki

    The flash welding is characterized by the high quality, the high production efficiency and the large sectional area welding, and is used to weld rails and hot coils in shop welding mainly. In order to realize high accuracy and high response control of flash welding, the inverter technology has been applied to flash welding in this study. In this paper, a method of process control combined with inverter flash control and mechanical control is proposed. Experiment results of the proposed process control combined with inverter flash control and mechanical control are presented.

  16. Application of Discontinuous PWM Modulation in Active Power Filters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Rodriguez, Pedro

    2008-01-01

    Classical discontinuous pulsewidth modulations (DPWMs) may not be efficiently applied in active power filters (APFs), because it is hard to predict the peak values of the inverter current, and consequently it is difficult to calculate the position of the clamped interval, that minimizes...

  17. Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Lungeanu, Florin; Sera, Dezso

    2012-01-01

    is very effective and is independent from the modulation index. The flat motor current spectrum generates an acoustical noise close to the white noise, which improves the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits...

  18. Adaptive control in series load PWM induction heating inverters

    Science.gov (United States)

    Szelitzky, Tibor; Henrietta Dulf, Eva

    2013-12-01

    Permanent variations of the electric properties of the load in induction heating equipment make difficult to control the plant. To overcome these disadvantages, the authors propose a new approach based on adaptive control methods. For real plants it is enough to present desired performances or start-up variables for the controller, from which the algorithms tune the controllers by itself. To present the advantages of the proposed controllers, comparisons are made to a PI controller tuned through Ziegler-Nichols method.

  19. A PWM transistor inverter for an ac electric vehicle drive

    Science.gov (United States)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  20. Advanced power electronics converters PWM converters processing AC voltages

    CERN Document Server

    dos Santos, Euzeli

    2014-01-01

    This book covers power electronics, in depth, by presenting the basic principles and application details, which can be used both as a textbook and reference book.  Introduces a new method to present power electronics converters called Power Blocks Geometry. Applicable for courses focusing on power electronics, power electronics converters, and advanced power converters. Offers a comprehensive set of simulation results to help understand the circuits presented throughout the book

  1. Effect of levamisole on immune function and reproductive performance in first-litter gilts.

    Science.gov (United States)

    Purswell, B J; Dawe, D L; Brown, J; Williams, D J

    1988-06-01

    First-litter commercial cross-bred gilts were treated with levamisole (1.5, 2.5, or 3.5 mg/kg of body weight) weekly during the last 4 weeks of gestation, because similar treatment of dairy heifers had improved postpartum maternal health and neonatal survival. In the gilts, differences in reproductive performance were not found on the basis of pig survival at birth, pig survival at weaning, birth weight, or weaning weight. Also, differences between treated and control gilts were not found in response of circulating lymphocytes to mitogen stimulation (phytohemagglutinin A, concanavalin A, and pokeweed mitogen). In all gilts, the lymphocyte response to mitogen stimulation was decreased during the first week after farrowing.

  2. Experimental porcine eperythrozoonosis: T-lymphocyte suppression and misdirected immune responses.

    Science.gov (United States)

    Zachary, J F; Smith, A R

    1985-04-01

    Immune responses and hematologic alterations were investigated in splenectomized pigs after IM inoculation with Eperythrozoon suis. Early hematologic alterations were massive parasitism of RBC, severe hypoglycemia, moderate bilirubinemia, and mild anemia; later findings included severe anemia, minimal parasitism of RBC, spontaneous agglutination of RBC at 25 C and 4 C which was reversible at 37 C, transient thrombocytopenia, and mild bilirubinemia. The humoral immune responses consisting of a transitory hyperglobulinemia and increase of indirect hemagglutination (IHA) titers against E suis were attributed to immunoglobulin M cold agglutinins. Cell-mediated immune responses, measured by phytohemagglutinin- and pokeweed mitogen-induced lymphocyte blastogenesis, were reduced after massive parasitemia. Blastogenesis induced by Escherichia coli lipopolysaccharide mitogen was increased before the hyperglobulinemia and an increase in IHA titer. There was an increase in the uptake of [3H]thymidine by lymphocytes cultured without mitogens after the decline in total globulin concentration and IHA titer.

  3. The p38 mitogen-activated protein kinase signaling pathway is involved in regulating low-density lipoprotein receptor-related protein 1-mediated β-amyloid protein internalization in mouse brain.

    Science.gov (United States)

    Ma, Kai-Ge; Lv, Jia; Hu, Xiao-Dan; Shi, Li-Li; Chang, Ke-Wei; Chen, Xin-Lin; Qian, Yi-Hua; Yang, Wei-Na; Qu, Qiu-Min

    2016-07-01

    Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Recently, increasing evidence suggests that intracellular β-amyloid protein (Aβ) alone plays a pivotal role in the progression of AD. Therefore, understanding the signaling pathway and proteins that control Aβ internalization may provide new insight for regulating Aβ levels. In the present study, the regulation of Aβ internalization by p38 mitogen-activated protein kinases (MAPK) through low-density lipoprotein receptor-related protein 1 (LRP1) was analyzed in vivo. The data derived from this investigation revealed that Aβ1-42 were internalized by neurons and astrocytes in mouse brain, and were largely deposited in mitochondria and lysosomes, with some also being found in the endoplasmic reticulum. Aβ1-42-LRP1 complex was formed during Aβ1-42 internalization, and the p38 MAPK signaling pathway was activated by Aβ1-42 via LRP1. Aβ1-42 and LRP1 were co- localized in the cells of parietal cortex and hippocampus. Furthermore, the level of LRP1-mRNA and LRP1 protein involved in Aβ1-42 internalization in mouse brain. The results of this investigation demonstrated that Aβ1-42 induced an LRP1-dependent pathway that related to the activation of p38 MAPK resulting in internalization of Aβ1-42. These results provide evidence supporting a key role for the p38 MAPK signaling pathway which is involved in the regulation of Aβ1-42 internalization in the parietal cortex and hippocampus of mouse through LRP1 in vivo. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Escherichia coli-derived and Staphylococcus aureus-derived extracellular vesicles induce MUC5AC expression via extracellular signal related kinase 1/2 and p38 mitogen-activated protein kinase in human airway epithelial cells.

    Science.gov (United States)

    Bae, Chang Hoon; Choi, Yoon Seok; Song, Si-Youn; Kim, Yoon-Keun; Kim, Yong-Dae

    2017-01-01

    Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) release extracellular vesicles (EVs). E. coli-derived and S. aureus-derived EVs are associated with neutrophilic respiratory inflammation. In neutrophilic respiratory inflammation of human, expression of mucin is increased in airway epithelial cells and is associated with increased morbidity and mortality of the affected patients. However, no study on the effects of EVs on expression of mucin genes has been reported in airway epithelial cells. Therefore, this study was conducted in order to examine the effects and the brief signaling pathways of E. coli-derived and S. aureus-derived EVs on MUC5AC expression in human airway epithelial cells. In mucin-producing human NCI-H292 airway epithelial cells and primary cultures of normal nasal epithelial cells, the effects and signaling pathways of E. coli-derived and S. aureus-derived EVs on MUC5AC expression were examined using reverse transcription-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with several specific inhibitors and small interfering RNA (siRNA). E. coli-derived and S. aureus-derived EVs induced MUC5AC expression. E. coli-derived and S. aureus-derived EVs significantly activated phosphorylation of extracellular signal related kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) and p38 MAPK. ERK1/2 MAPK inhibitor, p38 MAPK inhibitor, ERK1/2 MAPK siRNA, and p38 MAPK siRNA significantly blocked E. coli-derived and S. aureus-derived EVs induced MUC5AC messenger RNA (mRNA) expression. The results of this study suggest that E. coli-derived and S. aureus-derived EVs induced MUC5AC expression via ERK1/2 and p38 MAPK signaling pathways in human airway epithelial cells. © 2016 ARS-AAOA, LLC.

  5. Extract of Polygala tenuifolia Alleviates Stress-Exacerbated Atopy-Like Skin Dermatitis through the Modulation of Protein Kinase A and p38 Mitogen-Activated Protein Kinase Signaling Pathway.

    Science.gov (United States)

    Sur, Bongjun; Lee, Bombi; Yoon, Ye Seul; Lim, Pooreum; Hong, Riwon; Yeom, Mijung; Lee, Hyang Sook; Park, Hijoon; Shim, Insop; Lee, Hyejung; Jang, Young Pyo; Hahm, Dae-Hyun

    2017-01-18

    Atopic dermatitis (AD) and stress create a vicious cycle: stress exacerbates atopic symptoms, and atopic disease elicits stress and anxiety. Targeting multiple pathways including stress and allergic inflammation is, therefore, important for treating AD. In this study, we investigated the remedial value of Polygala tenuifolia Willd. (PTW) for treating immobilization (IMO) stress-exacerbated atopy-like skin dermatitis and its underlying mechanism. Trimellitic anhydride (TMA) was applied to dorsal skin for sensitization and subsequently both ears for eliciting T-cell-dependent contact hypersensitivity in mice, which underwent 2 h-IMO stress and PTW administration for the latter 6 and 9 days in the ear exposure period of TMA, respectively. To elicit in vitro degranulation of human mast cell line-1 (HMC-1), 10 µM substance P (SP) and 200 nM corticotrophin-releasing factor (CRF) were sequentially added with 48 h-interval. PTW extract (500 µg/mL) was added 30 min before CRF treatment. IMO stress exacerbated TMA-induced scratching behavior by 252%, and increased their blood corticosterone levels by two-fold. Treatment with 250 mg/kg PTW significantly restored IMO stress-exacerbated scratching behavior and other indicators such as skin inflammation and water content, lymph node weights, and serum histamine and immunoglobulin E (lgE) levels. Furthermore, it also reversed TMA-stimulated expression of tumor necrosis factor (TNF)-α and interleukin (IL)-4 mRNAs in ear tissues. PTW significantly inhibited SP/CRF-stimulated degranulation of HMC-1 cells, subsequent tryptase secretion, and protein kinase A (PKA) activity. PTW also selectively inhibited p38 mitogen-activated protein kinase (MAPK) phosphorylation in SP/CRF-treated HMC-1 cells. PTW significantly inhibited HMC-1 cell degranulation and alleviated IMO stress-exacerbated atopic dermatitis symptoms by modulating the PKA/p38 MAPK signaling pathway.

  6. Curcumin-induced apoptosis in ovarian carcinoma cells is p53-independent and involves p38 mitogen-activated protein kinase activation and downregulation of Bcl-2 and survivin expression and Akt signaling.

    Science.gov (United States)

    Watson, Jane L; Greenshields, Anna; Hill, Richard; Hilchie, Ashley; Lee, Patrick W; Giacomantonio, Carman A; Hoskin, David W

    2010-01-01

    New cytotoxic agents are urgently needed for the treatment of advanced ovarian cancer because of the poor long-term response of this disease to conventional chemotherapy. Curcumin, obtained from the rhizome of Curcuma longa, has potent anticancer activity; however, the mechanism of curcumin-induced cytotoxicity in ovarian cancer cells remains a mystery. In this study we show that curcumin exhibited time- and dose-dependent cytotoxicity against monolayer cultures of ovarian carcinoma cell lines with differing p53 status (wild-type p53: HEY, OVCA429; mutant p53: OCC1; null p53: SKOV3). In addition, p53 knockdown or p53 inhibition did not diminish curcumin killing of HEY cells, confirming p53-independent cytotoxicity. Curcumin also killed OVCA429, and SKOV3 cells grown as multicellular spheroids. Nuclear condensation and fragmentation, as well as DNA fragmentation and poly (ADP-ribose) polymerase-1 cleavage in curcumin-treated HEY cells, indicated cell death by apoptosis. Procaspase-3, procaspase-8, and procaspase-9 cleavage, in addition to cytochrome c release and Bid cleavage into truncated Bid, revealed that curcumin activated both the extrinsic and intrinsic pathways of apoptosis. Bax expression was unchanged but Bcl-2, survivin, phosphorylated Akt (on serine 473), and total Akt were downregulated in curcumin-treated HEY cells. Curcumin also activated p38 mitogen-activated protein kinase (MAPK) without altering extracellular signal-regulated kinase 1/2 activity. We conclude that p53-independent curcumin-induced apoptosis in ovarian carcinoma cells involves p38 MAPK activation, ablation of prosurvival Akt signaling, and reduced expression of the antiapoptotic proteins Bcl-2 and survivin. These data provide a mechanistic rationale for the potential use of curcumin in the treatment of ovarian cancer. 2009 Wiley-Liss, Inc.

  7. Enhanced expression of WD repeat-containing protein 35 (WDR35 stimulated by domoic acid in rat hippocampus: involvement of reactive oxygen species generation and p38 mitogen-activated protein kinase activation

    Directory of Open Access Journals (Sweden)

    Tsunekawa Koji

    2013-01-01

    Full Text Available Abstract Background Domoic acid (DA is an excitatory amino acid analogue of kainic acid (KA that acts via activation of glutamate receptors to elicit a rapid and potent excitotoxic response, resulting in neuronal cell death. Recently, DA was shown to elicit reactive oxygen species (ROS production and induce apoptosis accompanied by activation of p38 mitogen-activated protein kinase (MAPK in vitro. We have reported that WDR35, a WD-repeat protein, may mediate apoptosis in several animal models. In the present study, we administered DA to rats intraperitoneally, then used liquid chromatography/ion trap tandem mass spectrometry (LC-MS/MS to identify and quantify DA in the brains of the rats and performed histological examinations of the hippocampus. We further investigated the potential involvement of glutamate receptors, ROS, p38 MAPK, and WDR35 in DA-induced toxicity in vivo. Results Our results showed that intraperitoneally administered DA was present in the brain and induced neurodegenerative changes including apoptosis in the CA1 region of the hippocampus. DA also increased the expression of WDR35 mRNA and protein in a dose- and time-dependent manner in the hippocampus. In experiments using glutamate receptor antagonists, the AMPA/KA receptor antagonist NBQX significantly attenuated the DA-induced increase in WDR35 protein expression, but the NMDA receptor antagonist MK-801 did not. In addition, the radical scavenger edaravone significantly attenuated the DA-induced increase in WDR35 protein expression. Furthermore, NBQX and edaravone significantly attenuated the DA-induced increase in p38 MAPK phosphorylation. Conclusion In summary, our results indicated that DA activated AMPA/KA receptors and induced ROS production and p38 MAPK phosphorylation, resulting in an increase in the expression of WDR35 in vivo.

  8. Andrographolide stimulates p38 mitogen-activated protein kinase-nuclear factor erythroid-2-related factor 2-heme oxygenase 1 signaling in primary cerebral endothelial cells for definite protection against ischemic stroke in rats.

    Science.gov (United States)

    Yen, Ting-Lin; Chen, Ray-Jade; Jayakumar, Thanasekaran; Lu, Wan-Jung; Hsieh, Cheng-Ying; Hsu, Ming-Jen; Yang, Chih-Hao; Chang, Chao-Chien; Lin, Yen-Kuang; Lin, Kuan-Hung; Sheu, Joen-Rong

    2016-04-01

    Stroke pathogenesis involves complex oxidative stress-related pathways. The nuclear factor erythroid-2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1) pathways have been considered molecular targets in pharmacologic intervention for ischemic diseases. Andrographolide, a labdane diterpene, has received increasing attention in recent years because of its various pharmacologic activities. We determined that andrographolide modulates the mitogen-activated protein kinase (MAPK)-Nrf2-HO-1 signaling cascade in primary cerebral endothelial cells (CECs) to provide positive protection against middle cerebral artery occlusion (MCAO)-induced ischemic stroke in rats. In the present study, andrographolide (10 μM) increased HO-1 protein and messenger RNA expressions, Nrf2 phosphorylation, and nuclear translocation in CECs, and these activities were disrupted by a p38 MAPK inhibitor, SB203580, but not by the extracellular signal-regulated kinase inhibitor PD98059 or c-Jun amino-terminal kinase inhibitor SP600125. Similar results were observed in confocal microscopy analysis. Moreover, andrographolide-induced Nrf2 and HO-1 protein expressions were significantly inhibited by Nrf2 small interfering RNA. Moreover, HO-1 knockdown attenuated the protective effect of andrographolide against oxygen-glucose deprivation-induced CEC death. Andrographolide (0.1 mg/kg) significantly suppressed free radical formation, blood-brain barrier disruption, and brain infarction in MCAO-insulted rats, and these effects were reversed by the HO-1 inhibitor zinc protoporphyrin IX. The mechanism is attributable to HO-1 activation, as directly evidenced by andrographolide-induced pronounced HO-1 expression in brain tissues, which was highly localized in the cerebral capillary. In conclusion, andrographolide increased Nrf2-HO-1 expression through p38 MAPK regulation, confirming that it provides protection against MCAO-induced brain injury. These findings provide strong evidence that andrographolide could

  9. Insulin-Like Growth Factor 1 Receptor and p38 Mitogen-Activated Protein Kinase Signals Inversely Regulate Signal Transducer and Activator of Transcription 3 Activity to Control Human Dental Pulp Stem Cell Quiescence, Propagation, and Differentiation

    Science.gov (United States)

    Vandomme, Jerome; Touil, Yasmine; Ostyn, Pauline; Olejnik, Cecile; Flamenco, Pilar; El Machhour, Raja; Segard, Pascaline; Masselot, Bernadette; Bailliez, Yves; Formstecher, Pierre

    2014-01-01

    Dental pulp stem cells (DPSCs) remain quiescent until activated in response to severe dental pulp damage. Once activated, they exit quiescence and enter regenerative odontogenesis, producing reparative dentin. The factors and signaling molecules that control the quiescence/activation and commitment to differentiation of human DPSCs are not known. In this study, we determined that the inhibition of insulin-like growth factor 1 receptor (IGF-1R) and p38 mitogen-activated protein kinase (p38 MAPK) signaling commonly activates DPSCs and promotes their exit from the G0 phase of the cell cycle as well as from the pyronin Ylow stem cell compartment. The inhibition of these two pathways, however, inversely determines DPSC fate. In contrast to p38 MAPK inhibitors, IGF-1R inhibitors enhance dental pulp cell sphere-forming capacity and reduce the cells' colony-forming capacity without inducing cell death. The inverse cellular changes initiated by IGF-1R and p38 MAPK inhibitors were accompanied by inverse changes in the levels of active signal transducer and activator of transcription 3 (STAT3) factor, inactive glycogen synthase kinase 3, and matrix extracellular phosphoglycoprotein, a marker of early odontoblast differentiation. Our data suggest that there is cross talk between the IGF-1R and p38 MAPK signaling pathways in DPSCs and that the signals provided by these pathways converge at STAT3 and inversely regulate its activity to maintain quiescence or to promote self-renewal and differentiation of the cells. We propose a working model that explains the possible interactions between IGF-1R and p38 MAPK at the molecular level and describes the cellular consequences of these interactions. This model may inspire further fundamental study and stimulate research on the clinical applications of DPSC in cellular therapy and tissue regeneration. PMID:24266654

  10. Overcoming endocrine resistance due to reduced PTEN levels in estrogen receptor-positive breast cancer by co-targeting mammalian target of rapamycin, protein kinase B, or mitogen-activated protein kinase kinase.

    Science.gov (United States)

    Fu, Xiaoyong; Creighton, Chad J; Biswal, Nrusingh C; Kumar, Vijetha; Shea, Martin; Herrera, Sabrina; Contreras, Alejandro; Gutierrez, Carolina; Wang, Tao; Nanda, Sarmistha; Giuliano, Mario; Morrison, Gladys; Nardone, Agostina; Karlin, Kristen L; Westbrook, Thomas F; Heiser, Laura M; Anur, Pavana; Spellman, Paul; Guichard, Sylvie M; Smith, Paul D; Davies, Barry R; Klinowska, Teresa; Lee, Adrian V; Mills, Gordon B; Rimawi, Mothaffar F; Hilsenbeck, Susan G; Gray, Joe W; Joshi, Amit; Osborne, C Kent; Schiff, Rachel

    2014-09-11

    Activation of the phosphatidylinositol 3-kinase (PI3K) pathway in estrogen receptor α (ER)-positive breast cancer is associated with reduced ER expression and activity, luminal B subtype, and poor outcome. Phosphatase and tensin homolog (PTEN), a negative regulator of this pathway, is typically lost in ER-negative breast cancer. We set out to clarify the role of reduced PTEN levels in endocrine resistance, and to explore the combination of newly developed PI3K downstream kinase inhibitors to overcome this resistance. Altered cellular signaling, gene expression, and endocrine sensitivity were determined in inducible PTEN-knockdown ER-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer cell and/or xenograft models. Single or two-agent combinations of kinase inhibitors were examined to improve endocrine therapy. Moderate PTEN reduction was sufficient to enhance PI3K signaling, generate a gene signature associated with the luminal B subtype of breast cancer, and cause endocrine resistance in vitro and in vivo. The mammalian target of rapamycin (mTOR), protein kinase B (AKT), or mitogen-activated protein kinase kinase (MEK) inhibitors, alone or in combination, improved endocrine therapy, but the efficacy varied by PTEN levels, type of endocrine therapy, and the specific inhibitor(s). A single-agent AKT inhibitor combined with fulvestrant conferred superior efficacy in overcoming resistance, inducing apoptosis and tumor regression. Moderate reduction in PTEN, without complete loss, can activate the PI3K pathway to cause endocrine resistance in ER-positive breast cancer, which can be overcome by combining endocrine therapy with inhibitors of the PI3K pathway. Our data suggests that the ER degrader fulvestrant, to block both ligand-dependent and -independent ER signaling, combined with an AKT inhibitor is an effective strategy to test in patients.

  11. Cell surface marker profiling of human tracheal basal cells reveals distinct subpopulations, identifies MST1/MSP as a mitogenic signal, and identifies new biomarkers for lung squamous cell carcinomas.

    Science.gov (United States)

    Van de Laar, Emily; Clifford, Monica; Hasenoeder, Stefan; Kim, Bo Ram; Wang, Dennis; Lee, Sharon; Paterson, Josh; Vu, Nancy M; Waddell, Thomas K; Keshavjee, Shaf; Tsao, Ming-Sound; Ailles, Laurie; Moghal, Nadeem

    2014-12-31

    The large airways of the lungs (trachea and bronchi) are lined with a pseudostratified mucociliary epithelium, which is maintained by stem cells/progenitors within the basal cell compartment. Alterations in basal cell behavior can contribute to large airway diseases including squamous cell carcinomas (SQCCs). Basal cells have traditionally been thought of as a uniform population defined by basolateral position, cuboidal cell shape, and expression of pan-basal cell lineage markers like KRT5 and TP63. While some evidence suggests that basal cells are not all functionally equivalent, few heterogeneously expressed markers have been identified to purify and study subpopulations. In addition, few signaling pathways have been identified that regulate their cell behavior. The goals of this work were to investigate tracheal basal cell diversity and to identify new signaling pathways that regulate basal cell behavior. We used flow cytometry (FACS) to profile cell surface marker expression at a single cell level in primary human tracheal basal cell cultures that maintain stem cell/progenitor activity. FACS results were validated with tissue staining, in silico comparisons with normal basal cell and lung cancer datasets, and an in vitro proliferation assay. We identified 105 surface markers, with 47 markers identifying potential subpopulations. These subpopulations generally fell into more (~ > 13%) or less abundant (~ < 6%) groups. Microarray gene expression profiling supported the heterogeneous expression of these markers in the total population, and immunostaining of large airway tissue suggested that some of these markers are relevant in vivo. 24 markers were enriched in lung SQCCs relative to adenocarcinomas, with four markers having prognostic significance in SQCCs. We also identified 33 signaling receptors, including the MST1R/RON growth factor receptor, whose ligand MST1/MSP was mitogenic for basal cells. This work provides the largest description to date of

  12. Roles of Mitogen-Activating Protein Kinase Kinase Kinase Kinase-3 (MAP4K3) in Preterm Skeletal Muscle Satellite Cell Myogenesis and Mammalian Target of Rapamycin Complex 1 (mTORC1) Activation Regulation.

    Science.gov (United States)

    Guo, Chu-Yi; Yu, Mu-Xue; Dai, Jie-Min; Pan, Si-Nian; Lu, Zhen-Tong; Qiu, Xiao-Shan; Zhuang, Si-Qi

    2017-07-21

    BACKGROUND Preterm skeletal muscle genesis is a paradigm for myogenesis. The role of mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3) in preterm skeletal muscle satellite cells myogenesis or its relationship to mammalian target of rapamycin complex 1 (mTORC1) activity have not been previously elaborated. MATERIAL AND METHODS Small interfering RNA (siRNA) interference technology was used to inhibit MAP4K3 expression. Leucine stimulation experiments were performed following MAP4K3-siRNA interference. The differentiation of primary preterm skeletal muscle satellite cells was observed after siRNA-MAP4K3 interference. Western blot analysis was used to determine the expression of MAP4K3, MyHC, MyoD, myogenin, p-mTOR, and p-S6K1. The immunofluorescence fusion index of MyHC and myogenin were detected. MAP4K3 effects on preterm rat satellite cells differentiation and its relationship to mTORC1 activity are reported. RESULTS MAP4K3 siRNA knockdown inhibited myotube formation and both MyoD and myogenin expression in primary preterm rat skeletal muscle satellite cells, but MAP4K3 siRNA had no effect on the activity of mTORC1. In primary preterm rat skeletal muscle satellite cells, MAP4K3 knockdown resulted in significantly weaker, but not entirely blunted, leucine-induced mTORC1 signaling. CONCLUSIONS MAP4K3 positively regulates preterm skeletal muscle satellite cell myogenesis, but may not regulate mTORC1 activity. MAP4K3 may play a role in mTORC1 full activation in response to leucine.

  13. Nobiletin induces inhibitions of Ras activity and mitogen-activated protein kinase kinase/extracellular signal-regulated kinase signaling to suppress cell proliferation in C6 rat glioma cells.

    Science.gov (United States)

    Aoki, Koichi; Yokosuka, Akihito; Mimaki, Yoshihiro; Fukunaga, Kohji; Yamakuni, Tohru

    2013-01-01

    Ras, a small G-protein, physiologically directs cell proliferation and cell cycle via regulation of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling cascade. Dysregulation of Ras/MEK/ERK signaling has been reported to cause tumorigenesis and gliomas. Nobiletin, a citrus flavonoid, has been shown to have anti-tumor cells action. However, it remains elusive whether nobiletin could affect Ras activity. In this study, we provide the first evidence that nobiletin suppresses the proliferation by inhibiting Ras activity in C6 glioma cells, a rat glioma cell line. First, Ras pull-down assay showed that nobiletin inhibits Ras activity in a concentration-dependent manner in C6 cells. Second, farnesyltransferase inhibitor I, a Ras inhibitor, and U0126, a MEK inhibitor, induced an inhibition of the cell proliferation in C6 cells, while the cell proliferation was inhibited by nobiletin as well. Third, western blotting revealed that nobiletin showed inhibitory effects on MEK and ERK phopsphorylation levels in a concentration-dependent manner. Finally, such an inhibitory effect on the level of ERK phosphorylation by nobiletin was appreciably prevented by Gö6976, a selective inhibitor of conventional protein kinase Cs (PKCs) showing Ca(2+)-sensitivity, while GF109203X, a general inhibitor for PKCs, and BAPTA, a cell-permeable Ca(2+) chelator, to a lesser extent, suppressed a reduction of the phosphorylation. These findings suggest that the proliferation of C6 cells is Ras- and MEK/ERK signaling-dependent, and that nobiletin suppresses the cell proliferation by inhibiting Ras activity and MEK/ERK signaling cascade probably via a Ca(2+)-sensitive PKC-dependent mechanism. Thus, the natural compound has potential to be a therapeutic agent for glioma.

  14. Extract of Polygala tenuifolia Alleviates Stress-Exacerbated Atopy-Like Skin Dermatitis through the Modulation of Protein Kinase A and p38 Mitogen-Activated Protein Kinase Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Bongjun Sur

    2017-01-01

    Full Text Available Atopic dermatitis (AD and stress create a vicious cycle: stress exacerbates atopic symptoms, and atopic disease elicits stress and anxiety. Targeting multiple pathways including stress and allergic inflammation is, therefore, important for treating AD. In this study, we investigated the remedial value of Polygala tenuifolia Willd. (PTW for treating immobilization (IMO stress-exacerbated atopy-like skin dermatitis and its underlying mechanism. Trimellitic anhydride (TMA was applied to dorsal skin for sensitization and subsequently both ears for eliciting T-cell-dependent contact hypersensitivity in mice, which underwent 2 h-IMO stress and PTW administration for the latter 6 and 9 days in the ear exposure period of TMA, respectively. To elicit in vitro degranulation of human mast cell line-1 (HMC-1, 10 µM substance P (SP and 200 nM corticotrophin-releasing factor (CRF were sequentially added with 48 h-interval. PTW extract (500 µg/mL was added 30 min before CRF treatment. IMO stress exacerbated TMA-induced scratching behavior by 252%, and increased their blood corticosterone levels by two-fold. Treatment with 250 mg/kg PTW significantly restored IMO stress-exacerbated scratching behavior and other indicators such as skin inflammation and water content, lymph node weights, and serum histamine and immunoglobulin E (lgE levels. Furthermore, it also reversed TMA-stimulated expression of tumor necrosis factor (TNF-α and interleukin (IL-4 mRNAs in ear tissues. PTW significantly inhibited SP/CRF-stimulated degranulation of HMC-1 cells, subsequent tryptase secretion, and protein kinase A (PKA activity. PTW also selectively inhibited p38 mitogen-activated protein kinase (MAPK phosphorylation in SP/CRF-treated HMC-1 cells. PTW significantly inhibited HMC-1 cell degranulation and alleviated IMO stress-exacerbated atopic dermatitis symptoms by modulating the PKA/p38 MAPK signaling pathway.

  15. Progesterone increases brain-derived neuroptrophic factor expression and protects against glutamate toxicity in a mitogen-activated protein kinase- and phosphoinositide-3 kinase-dependent manner in cerebral cortical explants.

    Science.gov (United States)

    Kaur, Paramjit; Jodhka, Parmeet K; Underwood, Wendy A; Bowles, Courtney A; de Fiebre, Nancyellen C; de Fiebre, Christopher M; Singh, Meharvan

    2007-08-15

    The higher prevalence and risk for Alzheimer's disease in women relative to men has been partially attributed to the precipitous decline in gonadal hormone levels that occurs in women following the menopause. Although considerable attention has been focused on the consequence of estrogen loss, and thus estrogen's neuroprotective potential, it is important to recognize that the menopause results in a precipitous decline in progesterone levels as well. In fact, progesterone is neuroprotective, although the precise mechanisms involved remain unclear. Based on our previous observation that progesterone elicits the phosphorylation of ERK and Akt, key effectors of the neuroprotective mitogen-activated protein kinase (MAPK) and phosphoinositide-3 kinase (PI3-K) pathways, respectively, we determined whether activation of either of these pathways was necessary for progesterone-induced protection. With organotypic explants (slice culture) of the cerebral cortex, we found that progesterone protected against glutamate-induced toxicity. Furthermore, these protective effects were inhibited by either the MEK1/2 inhibitor UO126 or the PI3-K inhibitor LY294002, supporting the requirement for both the MAPK and PI3-K pathways in progesterone-induced protection. In addition, at a concentration and duration of treatment consistent with our neuroprotection data, progesterone also increased the expression of brain-derived neurotrophic factor (BDNF), at the level of both protein and mRNA. This induction of BDNF may be relevant to the protective effects of progesterone, in that inhibition of Trk signaling, with K252a, inhibited the protective effects of progesterone. Collectively, these data suggest that progesterone is protective via multiple and potentially related mechanisms. (c) 2007 Wiley-Liss, Inc. Copyright 2007 Wiley-Liss, Inc.

  16. Fluid shear stress stimulates osteogenic differentiation of human periodontal ligament cells via the extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase signaling pathways.

    Science.gov (United States)

    Tang, Min; Peng, Zhuli; Mai, Zhihui; Chen, Lin; Mao, Qin; Chen, Zheng; Chen, Qi; Liu, Limin; Wang, Yuxuan; Ai, Hong

    2014-12-01

    Fluid shear stress (FSS) is a major type of mechanical stress that is loaded on human periodontal ligament cells (hPDLCs) during mastication and orthodontic tooth movement. This study aims to clarify the effect of FSS on the osteogenic differentiation of hPDLCs and to further verify the involvement of mitogen-activated protein kinase (MAPK) signaling in this process. After isolation and characterization, hPDLCs were subjected to 2-hour FSS at 12 dynes/cm(2), and cell viability, osteogenic gene mRNA expression, alkaline phosphatase (ALP) activity, secretion of Type I collagen (COL-I), and calcium deposition were assayed. The levels of phosphorylated p38 and phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) in response to FSS were detected by Western blot, and the involvement of ERK1/2 and p38 MAPK signaling pathways in hPDLC osteogenesis under FSS was investigated using the specific MAPK inhibitors U0126 (2Z,3Z)-2,3-bis[amino(2-aminophenylthio)methylene]succinonitrile,ethanol) and SB203580 (4-[4-(4-fluorophenyl)-2-(4-[methylsulfinyl]phenyl)-1H-imidazol-5-yl]pyridine). The application of FSS on hPDLCs induced an early morphologic change and rearrangement of filamentous actin. ALP activity, messenger RNA (mRNA) levels of osteogenic genes, COL-I, and osteoid nodules were significantly increased by FSS. Moreover, ERK1/2 and p38 were activated in different ways after FSS exposure. U0126 and SB203580 completely blocked the FSS-induced increases in ALP activity and osteogenic gene mRNA expression and osteoid nodules formation. FSS is an effective approach for stimulating osteogenic differentiation of hPDLCs. The ERK1/2 and p38 MAPK signaling pathways are involved in this cellular process.

  17. Angiotensin II–Induced MMP-2 Activity and MMP-14 and Basigin Protein Expression Are Mediated via the Angiotensin II Receptor Type 1–Mitogen-Activated Protein Kinase 1 Pathway in Retinal Pigment Epithelium

    Science.gov (United States)

    Pons, Marianne; Cousins, Scott W.; Alcazar, Oscar; Striker, Gary E.; Marin-Castaño, Maria E.

    2011-01-01

    Accumulation of various lipid-rich extracellular matrix (ECM) deposits under the retinal pigment epithelium (RPE) has been observed in eyes with age-related macular degeneration (AMD). RPE-derived matrix metalloproteinase (MMP)-2, MMP-14, and basigin (BSG) are major enzymes involved in the maintenance of ECM turnover. Hypertension (HTN) is a systemic risk factor for AMD. It has previously been reported that angiotensin II (Ang II), one of the most important hormones associated with HTN, increases MMP-2 activity and its key regulator, MMP-14, in RPE, inducing breakdown of the RPE basement membrane, which may lead to progression of sub-RPE deposits. Ang II exerts most of its actions by activating the mitogen-activated protein kinase (MAPK) signaling pathway. Herein is explored the MAPK signaling pathway as a potential key intracellular modulator of Ang II–induced increase in MMP-2 activity and MMP-14 and BSG protein expression. It was observed that Ang II stimulates phosphorylation of extracellular signal-regulated kinase (ERK) and p38 MAPK in RPE cells and ERK/p38 and Jun N-terminal kinase (JNK) in mice. These effects were mediated by Ang II type 1 receptors. Blockade of ERK or p38 MAPK abrogated the increase in MMP-2 activity and MMP-14 and BSG proteins in ARPE-19 cells. A better understanding of the molecular events by which Ang II induces ECM dysregulation is of critical importance to further define its contribution to the progression of sub-RPE deposits in AMD patients with HTN. PMID:21641389

  18. Evaluation of the potential immunotoxicity of 3-monochloro-1,2-propanediol in Balb/c mice I. Effect on antibody forming cell, mitogen-stimulated lymphocyte proliferation, splenic subset, and natural killer cell activity

    International Nuclear Information System (INIS)

    Lee, Jong Kwon; Byun, Jung A.; Park, Seung Hee; Kim, Hyung Soo; Park, Jae Hyun; Eom, Juno H.; Oh, Hye Young

    2004-01-01

    3-Monochloro-1,2-propanediol (MCPD) is a well-known by-product of acid-hydrolyzed soy sauce during its manufacturing process. MCPD has been reported genotoxic in vitro, and reproductive toxicity and carcinogenicity in rats. However, no previous studies have investigated MCPD-induced alterations in the immune system. In the present study, MCPD was administered by gavage for 14 days at 0, 25, 50, and 100 mg/kg per day to female Balb/c mice. The antibody-mediated immune response to sheep red blood cells (SRBC) was assessed using the antibody-forming cell (AFC) assay, and splenic cell phenotypes were quantified by flow cytometry. Hematological and histopathological changes were assessed. Mitogen-stimulated spleen lymphocyte proliferation and natural killer (NK) cell activity were evaluated. The T-lymphocyte blastogenesis by concanavalin A (Con A) or anti-CD3 and B-lymphocyte blastogenesis by lipopolysaccharide (LPS) were not significantly changed. There were no significant changes in the hematological and histopathological findings of MCPD-treated mice. However, the significant decrease in thymus weight was observed in 100 mg dose group, even though that did not change body weight gain. The cellularities of spleen and thymus were significantly reduced in high-dose group. Exposure to high dose of MCPD decreased the AFC response to SRBC in mice. There was a significant decrease in NK cell activity of mice treated with high dose of MCPD. These results indicate that MCPD could modulate the immune function in Balb/c mice

  19. PsMPK7, a stress-associated mitogen-activated protein kinase (MAPK) in Phytophthora sojae, is required for stress tolerance, reactive oxygenated species detoxification, cyst germination, sexual reproduction and infection of soybean.

    Science.gov (United States)

    Gao, Jian; Cao, Mingna; Ye, Wenwu; Li, Haiyang; Kong, Liang; Zheng, Xiaobo; Wang, Yuanchao

    2015-01-01

    The sensing of stress signals and their transduction into appropriate responses are crucial for the adaptation, survival and infection of phytopathogenic fungi and oomycetes. Amongst evolutionarily conserved pathways, mitogen-activated protein kinase (MAPK) cascades function as key signal transducers that use phosphorylation to convey information. In this study, we identified a gene, designated PsMPK7, one of 14 predicted genes encoding MAPKs in Phytophthora sojae. PsMPK7 was highly transcribed in each tested stage, but was up-regulated in the zoospore, cyst and cyst germination stages. Silencing of PsMPK7 affected the growth of germinated cysts, oospore production and the pathogenicity of soybean. PsMPK7 transcription was induced by stresses from sorbitol, NaCl and hydrogen peroxide. Transformants in which PsMPK7 expression was silenced (PsMPK7-silenced) were significantly more sensitive to osmotic and oxidative stress. Aniline blue and diaminobenzidine staining revealed that the silenced lines did not suppress the host reactive oxygen species (ROS) burst, indicating that either the inoculated plants activated stronger defence responses to the transformants and/or the PsMPK7-silenced transformants failed to overcome plant defences. In addition, extracellular secretion of laccase decreased in the silenced lines. Overall, our results indicate that the PsMPK7 gene encodes a stress-associated MAPK in P. sojae that is important not only for responses to various stresses, but also for ROS detoxification, cyst germination, sexual oospore production and infection of soybean. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  20. Mitogen-activated protein kinases mediate Mycobacterium ...

    Indian Academy of Sciences (India)

    2012-01-19

    Jan 19, 2012 ... heat shock, UV irradiation and also to inflammatory cytokines. ERK is mainly activated by growth factors and phorbol esters. (Lewis et al. 1998; Cowan and Storey 2003). The activation of some MAPK family members by. M. tuberculosis H37Rv in human monocytes has already been reported. Song et al.