The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hsinhou Chang - One of the best experts on this subject based on the ideXlab platform.
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pi3 kinase is essential for adp stimulated integrin αiibβ3 mediated platelet Calcium Oscillation implications for p2y receptor pathways in integrin αiibβ3 initiated signaling cross talks
Journal of Biomedical Science, 2005Co-Authors: Dershan Sun, Chi Hung Lin, Yao Fong Chen, Weijern Tsai, Hsinhou ChangAbstract:Phosphatidylinositol 3-kinase (PI3K) pathway is important for platelet activation. Recent studies showed that PI3K and oscillative Calcium could cross talk to each other and positively regulate integrin alpha (IIb)beta3-mediated outside-in signaling. However, the mechanism of this feedback regulation remains to be further characterized. Here we found that treatments of both PI3K inhibitor wortmannin and P2Y1 inhibitor A3P5P could inhibit granular secretion in platelets. Additionally, when RGD-substrate adherent platelets were treated with the ADP scavenger apyrase to deplete the granular-released ADP, their attachments in engaging with substrates became looser and the frequency of Calcium Oscillation decreased. Since it is known that ADP stimulates the PI3K and Calcium signal primarily through P2Y12 and P2Y1 receptors respectively, our data indicated that integrin alpha(IIb)beta3 downstream PI3K and Calcium activation might be not completely coupled to integrin associated signaling complex, but in part through feedback stimulation by granular released ADP. Our data indicates the important roles of PI3K and granular released ADP in coordinating the feedback regulations in integrin alpha(IIb)beta3-mediated platelet activation.
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Calcium Oscillation and phosphatidylinositol 3 kinase positively regulate integrin αiibβ3 mediated outside in signaling
Journal of Biomedical Science, 2005Co-Authors: Dershan Sun, Chi Hung Lin, Ching Yi Huang, Yao Fong Chen, Hsinhou ChangAbstract:The frequency of Calcium Oscillation reveals the platelet activation status, however, the biological significance of the periodic Calcium responses and methods of communication with other integrin-mediated signals are not clear. RGD-containing disintegrin rhodostomin coated substrates were employed to enhance platelet spreading and Calcium Oscillation through direct binding and clustering of the receptor integrin αIIbβ3. The results showed that the activation of phosphatidylinositol 3-kinase (PI3-K) and internal Calcium pathways were crucial for αIIbβ3 outside-in signaling. PI3-K antagonists wortmannin and LY294002 inhibited disintegrin substrates and induced platelet spreading and Calcium Oscillation. At the same time, pretreatment of platelets with the microsomal Calcium–ATPase inhibitor thapsigargin to deplete internal Calcium stores severely impaired the Calcium Oscillation as well as PI3-K activation and spreading on disintegrin substrates. Because inhibition of one pathway could inhibit the other, our data indicates that PI3-K and Calcium Oscillation are synergistically operated and form a positive-feedback regulation in integrin αIIbβ3-mediated outside-in signaling.
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recombinant rhodostomin substrates induce transformation and active Calcium Oscillation in human platelets
Experimental Cell Research, 1999Co-Authors: Hsinhou Chang, Chi Hung LinAbstract:Platelet activation has been a focus of numerous studies in normal and abnormal states. Morphological changes and Calcium signals found with activated platelets in vitro have been well characterized. However, the rate of cell spreading on substrates and the frequency of Calcium Oscillation within individual platelets upon activation have not yet been reported. In this study, we first examined the ability of a recombinant fusion protein of rhodostomin (GST–rhodostomin), a snake disintegrin containing an Arg-Gly-Asp (RGD) motif, to activate platelets when GST–rhodostomin served as a substrate. Four aspects of platelet activities induced by immobilized GST–rhodostomin and fibrinogen were analyzed in parallel. Examinations of (1) translocation of P-selectin from intracellular compartments to the plasma membrane, (2) platelet adhesion to and spreading on substrates, (3) platelet contact pattern on substrates, and (4) the degree of phosphorylation of focal adhesion kinase in platelets indicated that GST–rhodostomin was a better substrate for platelet activation than fibrinogen. Analysis of the rate of platelet spreading on GST–rhodostomin was examined by time-lapsed video microscopy. The spreading rate averaged 0.43 μm/minute, while cell spreading averaged 0.22 μm/minute when platelets were plated on fibrinogen and treated with thrombin. A newly developed method, using time-lapsed microscopy and the Metamorph program, was used to analyze Calcium signals within platelets. We found that platelets on GST–rhodostomin evoked Calcium Oscillation at a frequency of 4.77 spike/cell/minute vs 2.76 spike/cell/minute on fibrinogen. The results of cell spreading and Calcium Oscillation were consistent with the results of microscopic and biochemical assays. We therefore conclude that the determination of the rate of platelet spreading and the frequency of Calcium Oscillation within platelets performed in this study provides more quantitative parameters for measuring platelet activities. Our results also suggest that GST–rhodostomin might potentially be used as a probe to dissect the molecular mechanisms underlying the kinetic processes of platelet activation.
Gen-xuan Wang - One of the best experts on this subject based on the ideXlab platform.
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Cytosolic Calcium Oscillation signaling in guard cell
Plant Science, 2004Co-Authors: Huimin Yang, Xiao-yan Zhang, Gen-xuan WangAbstract:Abstract Calcium signaling has been established to play a very important role in stomatal movements. More and more attentions have now been focused on cytosolic Calcium ([Ca 2+ ] cyt ) Oscillation in guard cell. It is still not clear how [Ca 2+ ] cyt Oscillation occurs and how it is decoded. Another point which attracted a lot of attentions is the relationship between the Oscillations in guard cell [Ca 2+ ] cyt and stomatal aperture. Recent data provide conclusive evidences that guard cell can decode complex Calcium Oscillation signaling and that [Ca 2+ ] cyt Oscillation in guard cell may induce stomatal Oscillation. This short review provides an introduction to [Ca 2+ ] cyt Oscillations in guard cell, the way in which they are generated and the correlations between [Ca 2+ ] cyt Oscillation and stomatal movements, especially stomatal Oscillation. The review concludes with a discussion that how [Ca 2+ ] cyt Oscillations are encoded and decoded, and a postulation that water channels may be involved in stomatal Oscillation.
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The parameters of guard cell Calcium Oscillation encodes stomatal Oscillation and closure in Vicia faba
Plant Science, 2004Co-Authors: Gen-xuan Wang, Ming Xin, Huimin YangAbstract:Oscillations in cytosolic Calcium ([Ca2+]cyt) are an important component of Ca2+-based signal transduction cascades and have been proposed as necessary for stomatal closure. The research about the roles of individual [Ca2+]cyt Oscillations parameters in regulating stomatal closure have been touched, but there still have many problems remaining largely unknown. We systematically vary the [Ca2+]cyt Oscillation parameters in Vicia faba L. guard cells to investigate their roles in stomatal movements. [Ca2+]cyt Oscillations could induce synchronous stomatal Oscillations and regulate the short-term stomatal closure during the Oscillation. The direct effect of [Ca2+]cyt on the activity of aquaporin may be the main cause of the stomatal Oscillation induced by [Ca2+]cyt Oscillations. Stomatal dynamics indicate the long-term steady-state stomatal closure can be apparently elicited by optimal [Ca2+]cyt Oscillation transient numbers and periods. The stomata in different growing phases have the different responses to the same [Ca2+]cyt Oscillation parameters.
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Cytosolic Calcium Oscillation may induce stomatal Oscillation in Vicia faba
Plant Science, 2003Co-Authors: Huimin Yang, Gen-xuan Wang, Xiao-yan Zhang, Yan LiAbstract:Abstract Whether guard cell cytosolic Calcium ([Ca2+]cyt) Oscillation induced stomatal Oscillation was investigated in Vicia faba leaf. Extracellular Ca2+, ABA and H2O2 treatments induced stomata to close in a dose- and time-dependent way. Both steady-state and rapid exchange treatments could first induce a steep decrease in stomatal aperture and then significantly induce stomatal Oscillations at small apertures. Steady-state extracellular Ca2+ and ABA treatments caused obvious but small and irregular stomatal Oscillations, and the Oscillations lasted for shorter time, while steady-state H2O2 treatment induced no stomatal Oscillation. Intriguingly, rapid exchange treatments of high [K+] buffer and high [Ca2+] buffer or high [ABA] buffer induced significant, strong, regular and longer time stomatal Oscillations, while no Oscillation occurred under H2O2 treatment in the same procedure. It was likely that [Ca2+]cyt Oscillations induced by extracellular Ca2+ and ABA could induce stomatal Oscillations and stomatal Oscillations occurred at small apertures.
Huimin Yang - One of the best experts on this subject based on the ideXlab platform.
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Cytosolic Calcium Oscillation signaling in guard cell
Plant Science, 2004Co-Authors: Huimin Yang, Xiao-yan Zhang, Gen-xuan WangAbstract:Abstract Calcium signaling has been established to play a very important role in stomatal movements. More and more attentions have now been focused on cytosolic Calcium ([Ca 2+ ] cyt ) Oscillation in guard cell. It is still not clear how [Ca 2+ ] cyt Oscillation occurs and how it is decoded. Another point which attracted a lot of attentions is the relationship between the Oscillations in guard cell [Ca 2+ ] cyt and stomatal aperture. Recent data provide conclusive evidences that guard cell can decode complex Calcium Oscillation signaling and that [Ca 2+ ] cyt Oscillation in guard cell may induce stomatal Oscillation. This short review provides an introduction to [Ca 2+ ] cyt Oscillations in guard cell, the way in which they are generated and the correlations between [Ca 2+ ] cyt Oscillation and stomatal movements, especially stomatal Oscillation. The review concludes with a discussion that how [Ca 2+ ] cyt Oscillations are encoded and decoded, and a postulation that water channels may be involved in stomatal Oscillation.
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The parameters of guard cell Calcium Oscillation encodes stomatal Oscillation and closure in Vicia faba
Plant Science, 2004Co-Authors: Gen-xuan Wang, Ming Xin, Huimin YangAbstract:Oscillations in cytosolic Calcium ([Ca2+]cyt) are an important component of Ca2+-based signal transduction cascades and have been proposed as necessary for stomatal closure. The research about the roles of individual [Ca2+]cyt Oscillations parameters in regulating stomatal closure have been touched, but there still have many problems remaining largely unknown. We systematically vary the [Ca2+]cyt Oscillation parameters in Vicia faba L. guard cells to investigate their roles in stomatal movements. [Ca2+]cyt Oscillations could induce synchronous stomatal Oscillations and regulate the short-term stomatal closure during the Oscillation. The direct effect of [Ca2+]cyt on the activity of aquaporin may be the main cause of the stomatal Oscillation induced by [Ca2+]cyt Oscillations. Stomatal dynamics indicate the long-term steady-state stomatal closure can be apparently elicited by optimal [Ca2+]cyt Oscillation transient numbers and periods. The stomata in different growing phases have the different responses to the same [Ca2+]cyt Oscillation parameters.
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Cytosolic Calcium Oscillation may induce stomatal Oscillation in Vicia faba
Plant Science, 2003Co-Authors: Huimin Yang, Gen-xuan Wang, Xiao-yan Zhang, Yan LiAbstract:Abstract Whether guard cell cytosolic Calcium ([Ca2+]cyt) Oscillation induced stomatal Oscillation was investigated in Vicia faba leaf. Extracellular Ca2+, ABA and H2O2 treatments induced stomata to close in a dose- and time-dependent way. Both steady-state and rapid exchange treatments could first induce a steep decrease in stomatal aperture and then significantly induce stomatal Oscillations at small apertures. Steady-state extracellular Ca2+ and ABA treatments caused obvious but small and irregular stomatal Oscillations, and the Oscillations lasted for shorter time, while steady-state H2O2 treatment induced no stomatal Oscillation. Intriguingly, rapid exchange treatments of high [K+] buffer and high [Ca2+] buffer or high [ABA] buffer induced significant, strong, regular and longer time stomatal Oscillations, while no Oscillation occurred under H2O2 treatment in the same procedure. It was likely that [Ca2+]cyt Oscillations induced by extracellular Ca2+ and ABA could induce stomatal Oscillations and stomatal Oscillations occurred at small apertures.
Weilong Duan - One of the best experts on this subject based on the ideXlab platform.
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time delay induces saw tooth Calcium wave and transition in intracellular Calcium Oscillation
Chinese Journal of Physics, 2020Co-Authors: Pengfei Duan, Xiping Yuan, Shu Gan, Yu Zhang, Weilong DuanAbstract:Abstract In view of same time delay τ in active and passive transport processes of intracellular Ca 2 + with additive Gaussian colored noise, using second-order algorithm for stochastic simulation colored noise, intracellular Calcium Oscillation (ICO) is investigated. By researching the time series and stationary probability distribution (SPD) of intracellular Ca 2 + concentrations, take modest strength and enough long correlation time of additive colored noise, the results indicate that: time delay has a critical point τc ≃ 0.1s of time coherence, as τ > τc, ICO become periodical Oscillation, and the waveform converts slowly into square wave from saw-tooth Calcium wave as time delay further increases. Additionally, ICO system appears transition from monostable state to bistable state as time delay increases.
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The phenomena of an intracellular Calcium Oscillation system with non-Gaussian noises☆
Chaos Solitons & Fractals, 2015Co-Authors: Ling Lin, Weilong DuanAbstract:Abstract An intracellular Calcium Oscillation (ICO) system with non-Gaussian noises in transmission processes of intracellular Ca 2 + is studied by means of a second-order stochastic Runge–Kutta type algorithm. The normalized autocorrelation function (NAF) and the characteristic correlation time (CCT) of cytosolic and Calcium store’s Ca 2 + concentration are simulated. The results exhibit that both NAFs of cytosolic and Calcium store’s Ca 2 + concentration show almost periodic Oscillation when the non-Gaussian noises are weak or the correlation time of non-Gaussian noises is long, but the Oscillations of both NAFs decrease when the non-Gaussian noises are strong or the correlation time is short. Moreover, both CCTs of cytosolic and Calcium store’s Ca 2 + concentration demonstrate that noises enhance stability, reverse resonance, and coherence resonance occur in the ICO system.
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colored noises decrease correlation in intracellular Calcium Oscillation
Chinese Journal of Physics, 2014Co-Authors: Weilong DuanAbstract:In view of the same time delay in the active and passive transmission processes with colored noises of the intracellular Ca^(2+), by means of a second-order algorithm for stochastic simulation of colored noises, the effect of colored noises on the normalized autocorrelation function (NAF) and characteristic correlation time (CCT) of the cytosolic and Calcium store's Ca^(2+) concentrations are presented, respectively. The results indicate that: (1) NAFs of the cytosolic and Calcium store's Ca^(2+) concentrations all appear with almost periodic Oscillation, and they decrease as colored noises strengthen but increase as the correlation time of the colored noises is prolonged; (2) the correlation of the intracellular Calcium Oscillation (ICO) system is decreased by strong colored noises.
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time delay induces oscillatory coherence in intracellular Calcium Oscillation system
Physica A-statistical Mechanics and Its Applications, 2014Co-Authors: Weilong DuanAbstract:Abstract In view of same time delay τ in active and passive transmission processes with colored noises of intracellular Ca 2+ , by means of second-order algorithm for stochastic simulation colored noises, the normalized autocorrelation function (NAF) and the characteristic correlation time (CCT) of cytosolic and Calcium store’s Ca 2+ concentration are studied. For the case of long τ : both NAFs of cytosolic and Calcium store’s Ca 2+ concentration exhibit periodically synchronous sawtooth wave, which linearly weakens as correlation time of colored noises or autocorrelation time increases. As τ increases, time delay induces oscillatory coherence in intracellular Calcium Oscillation system.
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colored noises commutate Calcium wave in intracellular Calcium Oscillation
Chinese Journal of Physics, 2014Co-Authors: Weilong Duan, Zebin FanAbstract:The revised role of colored noises in the intracellular Calcium Oscillation (ICO) system are investigated by means of a first-order algorithm for the stochastic simulation of colored noises. The simulation results showed clearly that the colored noises commutate a Calcium wave. Concretely, for a correlation time of colored noise τ1 there exists a threshold value τc which plays an important role in shifting a Calcium wave from negative to positive, however, the Calcium wave will show negative regardless of any noise's correlation time taking any value, so long as τ1 ＜ τc. So considering colored noises in the ICO could explain reasonably the ICO phenomenon.
Chi Hung Lin - One of the best experts on this subject based on the ideXlab platform.
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pi3 kinase is essential for adp stimulated integrin αiibβ3 mediated platelet Calcium Oscillation implications for p2y receptor pathways in integrin αiibβ3 initiated signaling cross talks
Journal of Biomedical Science, 2005Co-Authors: Dershan Sun, Chi Hung Lin, Yao Fong Chen, Weijern Tsai, Hsinhou ChangAbstract:Phosphatidylinositol 3-kinase (PI3K) pathway is important for platelet activation. Recent studies showed that PI3K and oscillative Calcium could cross talk to each other and positively regulate integrin alpha (IIb)beta3-mediated outside-in signaling. However, the mechanism of this feedback regulation remains to be further characterized. Here we found that treatments of both PI3K inhibitor wortmannin and P2Y1 inhibitor A3P5P could inhibit granular secretion in platelets. Additionally, when RGD-substrate adherent platelets were treated with the ADP scavenger apyrase to deplete the granular-released ADP, their attachments in engaging with substrates became looser and the frequency of Calcium Oscillation decreased. Since it is known that ADP stimulates the PI3K and Calcium signal primarily through P2Y12 and P2Y1 receptors respectively, our data indicated that integrin alpha(IIb)beta3 downstream PI3K and Calcium activation might be not completely coupled to integrin associated signaling complex, but in part through feedback stimulation by granular released ADP. Our data indicates the important roles of PI3K and granular released ADP in coordinating the feedback regulations in integrin alpha(IIb)beta3-mediated platelet activation.
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Calcium Oscillation and phosphatidylinositol 3 kinase positively regulate integrin αiibβ3 mediated outside in signaling
Journal of Biomedical Science, 2005Co-Authors: Dershan Sun, Chi Hung Lin, Ching Yi Huang, Yao Fong Chen, Hsinhou ChangAbstract:The frequency of Calcium Oscillation reveals the platelet activation status, however, the biological significance of the periodic Calcium responses and methods of communication with other integrin-mediated signals are not clear. RGD-containing disintegrin rhodostomin coated substrates were employed to enhance platelet spreading and Calcium Oscillation through direct binding and clustering of the receptor integrin αIIbβ3. The results showed that the activation of phosphatidylinositol 3-kinase (PI3-K) and internal Calcium pathways were crucial for αIIbβ3 outside-in signaling. PI3-K antagonists wortmannin and LY294002 inhibited disintegrin substrates and induced platelet spreading and Calcium Oscillation. At the same time, pretreatment of platelets with the microsomal Calcium–ATPase inhibitor thapsigargin to deplete internal Calcium stores severely impaired the Calcium Oscillation as well as PI3-K activation and spreading on disintegrin substrates. Because inhibition of one pathway could inhibit the other, our data indicates that PI3-K and Calcium Oscillation are synergistically operated and form a positive-feedback regulation in integrin αIIbβ3-mediated outside-in signaling.
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recombinant rhodostomin substrates induce transformation and active Calcium Oscillation in human platelets
Experimental Cell Research, 1999Co-Authors: Hsinhou Chang, Chi Hung LinAbstract:Platelet activation has been a focus of numerous studies in normal and abnormal states. Morphological changes and Calcium signals found with activated platelets in vitro have been well characterized. However, the rate of cell spreading on substrates and the frequency of Calcium Oscillation within individual platelets upon activation have not yet been reported. In this study, we first examined the ability of a recombinant fusion protein of rhodostomin (GST–rhodostomin), a snake disintegrin containing an Arg-Gly-Asp (RGD) motif, to activate platelets when GST–rhodostomin served as a substrate. Four aspects of platelet activities induced by immobilized GST–rhodostomin and fibrinogen were analyzed in parallel. Examinations of (1) translocation of P-selectin from intracellular compartments to the plasma membrane, (2) platelet adhesion to and spreading on substrates, (3) platelet contact pattern on substrates, and (4) the degree of phosphorylation of focal adhesion kinase in platelets indicated that GST–rhodostomin was a better substrate for platelet activation than fibrinogen. Analysis of the rate of platelet spreading on GST–rhodostomin was examined by time-lapsed video microscopy. The spreading rate averaged 0.43 μm/minute, while cell spreading averaged 0.22 μm/minute when platelets were plated on fibrinogen and treated with thrombin. A newly developed method, using time-lapsed microscopy and the Metamorph program, was used to analyze Calcium signals within platelets. We found that platelets on GST–rhodostomin evoked Calcium Oscillation at a frequency of 4.77 spike/cell/minute vs 2.76 spike/cell/minute on fibrinogen. The results of cell spreading and Calcium Oscillation were consistent with the results of microscopic and biochemical assays. We therefore conclude that the determination of the rate of platelet spreading and the frequency of Calcium Oscillation within platelets performed in this study provides more quantitative parameters for measuring platelet activities. Our results also suggest that GST–rhodostomin might potentially be used as a probe to dissect the molecular mechanisms underlying the kinetic processes of platelet activation.
