Effects of the cell adhesion peptide, Arg-Gly-Asp-Ser, on responses of washed platelets from humans, rabbits, and rats

Harfenist, EJ; Packham, MA; Mustard, J. F.

doi:10.1182/blood.v71.1.132.132

Cited by 63 publications

(25 citation statements)

References 31 publications

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“…When stirred platelets were pre-treated (1 min) with a maximally effective concentration (1 mM) of RGDS (Arg-Gly-Asp-Ser), a fibrinogen-derived peptide which specifically inhibits the platelet aggregatory response [17,18], PMA (1 min)-induced aggregation was abolished, the decrease in cytosolic PKC activity was accompanied by increases in membrane-bound PKC, and the loss of total cellular PKC was completely prevented ( Table 2).…”

Section: Resultsmentioning

confidence: 99%

Receptor- and phorbol-ester-mediated redistribution of protein kinase C in human platelets. Evidence that aggregation promotes degradation of protein kinase C

Wheeler‐Jones

Patel

Kakkar

et al. 1989

Biochemical Journal

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Translocation of Ca2+/phospholipid-dependent protein kinase (PKC) activity from cytosolic to membrane fractions was assessed in washed human platelet suspensions. Phorbol myristate acetate (PMA) induced a rapid loss of PKC activity from the cytosolic compartment in stirred platelets, which was not accompanied by measurable increases in membrane-associated activity, but was paralleled by a decrease in total cellular enzyme activity (cytosol plus membrane). When platelet aggregation was prevented by not stirring, (i) cytosolic activity was decreased by PMA, (ii) significant and maintained (1-15 min with PMA) increases in membrane-bound PKC were detected, and (iii) the decline in total enzyme activity was markedly slower. In stirred platelets, total and specific inhibition of PMA-induced aggregation by a fibrinogen-derived peptide (RGDS, i.e. Arg-Gly-Asp-Ser) promoted maximal increases in membrane-associated PKC in the presence of PMA and completely prevented the loss in cellular activity. Thrombin and collagen both induced a decrease in cytosolic PKC and a loss of total activity, but a significant rise in membrane activity was seen only with collagen; ADP had no detectable effect on enzyme distribution. These results demonstrate an agonist-induced redistribution of PKC and indicate that platelet aggregation may play an important role in the proteolysis, and hence persistence, of membrane-associated PKC. This observation has implications for the potency and duration of PKC-mediated responses induced by agonists and exogenous PKC activators.

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Section: Resultsmentioning

confidence: 99%

Receptor- and phorbol-ester-mediated redistribution of protein kinase C in human platelets. Evidence that aggregation promotes degradation of protein kinase C

Wheeler‐Jones

Patel

Kakkar

et al. 1989

Biochemical Journal

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“…The general consensus of these reports is that platelet GPIIb-IIIa in conventional small animals used for in vivo studies (e.g. rats, mice, rabbits) are relatively less sensitive to RGD-based peptides, compared to GPIIb-IIIa of human platelets [32,33]. Consequently, a small animal model for in vivo testing of RGD-GPIIb-IIIa interaction is rare.…”

Section: Discussionmentioning

confidence: 99%

Affinity manipulation of surface-conjugated RGD peptide to modulate binding of liposomes to activated platelets

et al. 2008

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Platelet adhesion, activation and fibrinogen-mediated aggregation are primary events in vascular thrombosis and occlusion. An injectable delivery system that can carry thrombolytics selectively to the sites of active platelet aggregation has immense potential in minimally invasive targeted therapy of vascular occlusion. To this end we are studying liposomes surface-modified by fibrinogen-mimetic RGD motifs that can selectively target and bind integrin GPIIb-IIIa on activated platelets. Here we report liposome surface-modification with a conformationally constrained high affinity cyclic RGD motif to modulate the GPIIb-IIIa-binding capability of the liposomes. Such affinity enhancement is important for practical in vivo applications to compete with native fibrinogen towards binding GPIIb-IIIa. The platelet-binding of RGD-modified liposomes was studied by fluorescence and scanning electron microscopy, and flow cytometry, in vitro. Binding of RGD-modified liposomes was also tested in vivo in a rat carotid injury model and analyzed ex vivo by fluorescence microscopy. The results from all experiments show that cyclic RGD-liposomes bind activated platelets significantly higher compared to linear RGD-liposomes. Hence, the results establish the feasibility of modulating the platelet-targeting and binding ability of vascularly targeted liposomes by manipulating the affinity of surface-modifying ligands.

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“…RGDW peptide, which effectively inhibits GPIIb-IIIa-mediated platelet spreading, was used to determine the surface area covered by attached, but not spread, platelets. Since rodent GPIIb-IIIa is relatively less sensitive to inhibition by RGD peptide than is human GPIIb-IIIa (IC 50 ¼ 1.65 versus 0.04 mM, respectively) [19,20], it was used at a concentration of 2 mM, which has previously been shown to inhibit VWF/botrocetin-induced aggregation and spreading of murine platelets [18].…”

Section: Platelet Adhesion and Spreading On Vwf Under Static Conditionsmentioning

confidence: 99%

Phospholipase Cγ2 contributes to stable thrombus formation on VWF

et al. 2004

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Though phospholipase C PLCc2 is known to play an important role in platelet activation by collagen and fibrinogen, its importance in GPIb-mediated platelet activation is less well understood. To better understand the role of PLCc2 in GPIbmediated adhesion and thrombus formation, we examined the ability of wild-type and PLCc2-deficient murine platelets to spread on immobilized von Willebrand factor (VWF) under static conditions, and to attach to and form thrombi on VWF under conditions of arterial shear. While absence of PLCc2 had only a minimal effect on platelet adhesion to immobilized VWF, its absence impaired spreading and profoundly affected thrombus growth and stability on VWF.

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Effects of the cell adhesion peptide, Arg-Gly-Asp-Ser, on responses of washed platelets from humans, rabbits, and rats

Cited by 63 publications

References 31 publications

Receptor- and phorbol-ester-mediated redistribution of protein kinase C in human platelets. Evidence that aggregation promotes degradation of protein kinase C

Receptor- and phorbol-ester-mediated redistribution of protein kinase C in human platelets. Evidence that aggregation promotes degradation of protein kinase C

Affinity manipulation of surface-conjugated RGD peptide to modulate binding of liposomes to activated platelets

Phospholipase Cγ2 contributes to stable thrombus formation on VWF

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