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Pharmacological actions of nobiletin in the modulation of platelet function.

Vaiyapuri S, Roweth H, Ali MS, Unsworth AJ, Stainer AR, Flora GD, Crescente M, Jones CI, Moraes LA, Gibbins JM - Br. J. Pharmacol. (2015)

Bottom Line: The effect of nobiletin in vivo was assessed by measuring tail bleeding time using C57BL/6 mice.Nobiletin extended bleeding time in mice and reduced the phosphorylation of PKB (Akt) and PLCγ2 within the collagen receptor (glycoprotein VI)-stimulated pathway, in addition to increasing the levels of cGMP and phosphorylation of vasodilator-stimulated phosphoprotein, a protein whose activity is associated with inhibitory cyclic nucleotide signalling.Therefore, nobiletin may represent a potential antithrombotic agent of dietary origins.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK.

No MeSH data available.


Related in: MedlinePlus

Integrin αIIbβ3-mediated outside-in signalling is inhibited by nobiletin. The effect of various concentrations of nobiletin (12.5, 25, 50 and 100 μM) on clot retraction was analysed in vitro using human PRP (A and B). (A) Representative image of clot retraction at 2 h in the presence or absence of different concentrations of nobiletin. Data in (B) represent mean ± SD (n = 4) of clot weights measured at 2 h. Washed human platelets were allowed to spread for 45 min in the presence and absence of 100 μM nobiletin on 100 μg·mL−1 fibrinogen-coated cover glasses and stained with Alexa fluor 488 labelled phalloidin prior to analysis using a Nikon A1-R-confocal microscope. The images shown in (C) are representative of multiple images acquired from four separate experiments. The images were analysed by ImageJ and the number of platelets found at different states of platelet spreading were calculated (D). The P-values were calculated using parametric repeated measures anova (***P = <0.001 and ****P = <0.0001).
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fig03: Integrin αIIbβ3-mediated outside-in signalling is inhibited by nobiletin. The effect of various concentrations of nobiletin (12.5, 25, 50 and 100 μM) on clot retraction was analysed in vitro using human PRP (A and B). (A) Representative image of clot retraction at 2 h in the presence or absence of different concentrations of nobiletin. Data in (B) represent mean ± SD (n = 4) of clot weights measured at 2 h. Washed human platelets were allowed to spread for 45 min in the presence and absence of 100 μM nobiletin on 100 μg·mL−1 fibrinogen-coated cover glasses and stained with Alexa fluor 488 labelled phalloidin prior to analysis using a Nikon A1-R-confocal microscope. The images shown in (C) are representative of multiple images acquired from four separate experiments. The images were analysed by ImageJ and the number of platelets found at different states of platelet spreading were calculated (D). The P-values were calculated using parametric repeated measures anova (***P = <0.001 and ****P = <0.0001).

Mentions: Following binding to fibrinogen, integrin αIIbβ3 clustering transduces signals (outside-in signalling) into platelets to allow spreading and in the latter phase of its formation, clot retraction (Calderwood, 2004). The modulatory effects of nobiletin on integrin αIIbβ3-mediated outside-in signalling were analysed by measuring clot retraction and platelet spreading under static conditions. Clot formation was initiated by adding thrombin to PRP in the absence or presence of nobiletin (12.5, 25, 50 and 100 μM), and the rate of clot retraction was monitored over 2 h by measuring the remaining clot weight. Although the initial clot formation was normal in vehicle and nobiletin-treated samples, clot retraction was reduced significantly in the presence of nobiletin (100 μM) at 2 h compared with the control samples (Figure 3A and 3B). Similarly, nobiletin-treated (100 μM) platelets were unable spread on fibrinogen to a similar extent to control platelets at 45 min. Most nobiletin-treated platelets failed to progress beyond filopodia formation with only a few cells progressing to lamellapodia formation and full spreading (Figure 3C and 3D). These data suggest that outside-in signalling through integrin αIIbβ3, which controls the coordinated process of clot retraction and platelet spreading on fibrinogen, is affected by nobiletin.


Pharmacological actions of nobiletin in the modulation of platelet function.

Vaiyapuri S, Roweth H, Ali MS, Unsworth AJ, Stainer AR, Flora GD, Crescente M, Jones CI, Moraes LA, Gibbins JM - Br. J. Pharmacol. (2015)

Integrin αIIbβ3-mediated outside-in signalling is inhibited by nobiletin. The effect of various concentrations of nobiletin (12.5, 25, 50 and 100 μM) on clot retraction was analysed in vitro using human PRP (A and B). (A) Representative image of clot retraction at 2 h in the presence or absence of different concentrations of nobiletin. Data in (B) represent mean ± SD (n = 4) of clot weights measured at 2 h. Washed human platelets were allowed to spread for 45 min in the presence and absence of 100 μM nobiletin on 100 μg·mL−1 fibrinogen-coated cover glasses and stained with Alexa fluor 488 labelled phalloidin prior to analysis using a Nikon A1-R-confocal microscope. The images shown in (C) are representative of multiple images acquired from four separate experiments. The images were analysed by ImageJ and the number of platelets found at different states of platelet spreading were calculated (D). The P-values were calculated using parametric repeated measures anova (***P = <0.001 and ****P = <0.0001).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4543618&req=5

fig03: Integrin αIIbβ3-mediated outside-in signalling is inhibited by nobiletin. The effect of various concentrations of nobiletin (12.5, 25, 50 and 100 μM) on clot retraction was analysed in vitro using human PRP (A and B). (A) Representative image of clot retraction at 2 h in the presence or absence of different concentrations of nobiletin. Data in (B) represent mean ± SD (n = 4) of clot weights measured at 2 h. Washed human platelets were allowed to spread for 45 min in the presence and absence of 100 μM nobiletin on 100 μg·mL−1 fibrinogen-coated cover glasses and stained with Alexa fluor 488 labelled phalloidin prior to analysis using a Nikon A1-R-confocal microscope. The images shown in (C) are representative of multiple images acquired from four separate experiments. The images were analysed by ImageJ and the number of platelets found at different states of platelet spreading were calculated (D). The P-values were calculated using parametric repeated measures anova (***P = <0.001 and ****P = <0.0001).
Mentions: Following binding to fibrinogen, integrin αIIbβ3 clustering transduces signals (outside-in signalling) into platelets to allow spreading and in the latter phase of its formation, clot retraction (Calderwood, 2004). The modulatory effects of nobiletin on integrin αIIbβ3-mediated outside-in signalling were analysed by measuring clot retraction and platelet spreading under static conditions. Clot formation was initiated by adding thrombin to PRP in the absence or presence of nobiletin (12.5, 25, 50 and 100 μM), and the rate of clot retraction was monitored over 2 h by measuring the remaining clot weight. Although the initial clot formation was normal in vehicle and nobiletin-treated samples, clot retraction was reduced significantly in the presence of nobiletin (100 μM) at 2 h compared with the control samples (Figure 3A and 3B). Similarly, nobiletin-treated (100 μM) platelets were unable spread on fibrinogen to a similar extent to control platelets at 45 min. Most nobiletin-treated platelets failed to progress beyond filopodia formation with only a few cells progressing to lamellapodia formation and full spreading (Figure 3C and 3D). These data suggest that outside-in signalling through integrin αIIbβ3, which controls the coordinated process of clot retraction and platelet spreading on fibrinogen, is affected by nobiletin.

Bottom Line: The effect of nobiletin in vivo was assessed by measuring tail bleeding time using C57BL/6 mice.Nobiletin extended bleeding time in mice and reduced the phosphorylation of PKB (Akt) and PLCγ2 within the collagen receptor (glycoprotein VI)-stimulated pathway, in addition to increasing the levels of cGMP and phosphorylation of vasodilator-stimulated phosphoprotein, a protein whose activity is associated with inhibitory cyclic nucleotide signalling.Therefore, nobiletin may represent a potential antithrombotic agent of dietary origins.

View Article: PubMed Central - PubMed

Affiliation: Institute for Cardiovascular and Metabolic Research, School of Biological Sciences, University of Reading, Reading, UK.

No MeSH data available.


Related in: MedlinePlus