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1

Shebuski, R. J., D. E. Berry, D. B. Bennett, et al. "Demonstration of Ac-Arg-Gly-Asp-Ser-NH2 as an Antiaggregatory Agent in the Dog by Intracoronary Administration." Thrombosis and Haemostasis 61, no. 02 (1989): 183–88. http://dx.doi.org/10.1055/s-0038-1646556.

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SummaryThis study compared the anti-platelet effect of Ac-RGDS-NH2 which is a peptide fragment from fibrinogen to Ac-RGES-NH2 in which the aspartic acid (D) of Ac-RGDS-NH2 has been replaced by glutamic acid (E). When Ac-RGDS-NH2 was infused intracoronary at concentrations of 100–400 mM, acute platelet dependent thrombus formation in the dog coronary artery was inhibited. However, infusion of Ac-RGES-NH2 intracoronary at similar concentrations to Ac-RGDS-NH2 failed to inhibit platelet dependent thrombus formation in the dog. Ac-RGDS-NH2 and Ac-RGES-NH2 were also tested for their ability to inhibit collagen-induced platelet aggregation in vitro. Ac-RGDS-NH2 elicited concentration-dependent inhibition of collagen-induced aggregation with no effect of Ac-RGES-NHz otr collagen-induced platelet aggregation. Thus, Ac-RGDS-NH2 is an effective antiplatelet agent after intracoronary administration in the dog and also inhibits collagen-induced platelet aggregation in vitro. Ac-RGDS-NH2 is a specific inhibitor of platelet aggregation as replacement of the aspartic acid in Ac-RGDS-NH2 with glutamic acid results in complete loss of biological activity.
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2

Plow, EF, MD Pierschbacher, E. Ruoslahti, G. Marguerie, and MH Ginsberg. "Arginyl-glycyl-aspartic acid sequences and fibrinogen binding to platelets." Blood 70, no. 1 (1987): 110–15. http://dx.doi.org/10.1182/blood.v70.1.110.110.

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Abstract Human fibrinogen has an Arg-Gly-Asp-Ser (RGDS) sequence at residues 572- 575 of its A alpha-chain. Although RGDS-containing peptides inhibit fibrinogen binding to stimulated platelets, these peptides also inhibit platelet binding of human fibrinogen fragment X and rat fibrinogen, which lack RGDS sequences corresponding to A alpha 572–575. Thus competition between free RGD-containing peptides and internal RGDS sequence at A alpha 572–575 is not the basis for their inhibition of fibrinogen binding to platelets. Addition of a Thr to the carboxy- terminus and an Asn to the amino-terminus of the RGDS sequence, the amino acids corresponding to A alpha 576 and 571 respectively, reduced the inhibitory potency of RGDS-containing peptides by fourfold to tenfold. Arg-Gly-Asp-Phe (RGDF) corresponds to A alpha 95–98, and the RGDF peptide was an effective inhibitor of fibrinogen binding, fourfold to fivefold more potent than RGDS. Thus, local primary structure may play an important role in regulating the capacity of RGD sequences in proteins to interact with specific adhesion receptors.
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3

Plow, EF, MD Pierschbacher, E. Ruoslahti, G. Marguerie, and MH Ginsberg. "Arginyl-glycyl-aspartic acid sequences and fibrinogen binding to platelets." Blood 70, no. 1 (1987): 110–15. http://dx.doi.org/10.1182/blood.v70.1.110.bloodjournal701110.

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Human fibrinogen has an Arg-Gly-Asp-Ser (RGDS) sequence at residues 572- 575 of its A alpha-chain. Although RGDS-containing peptides inhibit fibrinogen binding to stimulated platelets, these peptides also inhibit platelet binding of human fibrinogen fragment X and rat fibrinogen, which lack RGDS sequences corresponding to A alpha 572–575. Thus competition between free RGD-containing peptides and internal RGDS sequence at A alpha 572–575 is not the basis for their inhibition of fibrinogen binding to platelets. Addition of a Thr to the carboxy- terminus and an Asn to the amino-terminus of the RGDS sequence, the amino acids corresponding to A alpha 576 and 571 respectively, reduced the inhibitory potency of RGDS-containing peptides by fourfold to tenfold. Arg-Gly-Asp-Phe (RGDF) corresponds to A alpha 95–98, and the RGDF peptide was an effective inhibitor of fibrinogen binding, fourfold to fivefold more potent than RGDS. Thus, local primary structure may play an important role in regulating the capacity of RGD sequences in proteins to interact with specific adhesion receptors.
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4

Hirano, Yoshiaki, Yoshihiro Kando, Toshio Hayashi, Kunio Goto, and Akio Nakajima. "Synthesis and cell attachment activity of bioactive oligopeptides: RGD, RGDS, RGDV, and RGDT." Journal of Biomedical Materials Research 25, no. 12 (1991): 1523–34. http://dx.doi.org/10.1002/jbm.820251209.

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5

Donaldson, D. J., J. T. Mahan, and G. N. Smith. "Newt epidermal cell migration over collagen and fibronectin involves different mechanisms." Journal of Cell Science 90, no. 2 (1988): 325–33. http://dx.doi.org/10.1242/jcs.90.2.325.

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Effects of the synthetic peptides, Arg-Gly-Asp-Ser (RGDS), the amino acid sequence representing the fibroblast attachment site in fibronectin, and Arg-Gly-Glu-Ser (RGES), on collagen- and fibronectin-mediated migration in newt epidermal cells were compared. When RGDS at 50 micrograms ml-1 was included in the incubation medium of skin explants, migration in fibronectin-coated dishes was almost totally blocked. In type I collagen-coated dishes, this concentration of RGDS also inhibited migration, but to a lesser degree than on fibronectin. With 250 micrograms ml-1 of RGES in the medium, the reverse was true. Here, migration on collagen was practically non-existent, while migration on fibronectin was affected only moderately. Collagen-mediated migration was sensitive to RGDS even when the peptide was added after migration on the coated substratum was well underway. At a coating concentration of 10 micrograms ml-1 CB3, a cyanogen bromide fragment of the collagen alpha 1(I) chain, which contains no RGD sequences, was as good a migration substratum as intact collagen applied at the same coating concentration. At lower concentrations intact collagen was somewhat better than equivalent concentrations of CB3. The presence of RGDS in the medium throughout an experiment inhibited migration in CB3-coated dishes in a manner similar to its effect in dishes coated with collagen. On both substrata there appeared to be a peptide-sensitive and a peptide-insensitive component to migration. The inhibitory effect of RGES on CB3-mediated migration was also similar to its effect in collagen-coated dishes.(ABSTRACT TRUNCATED AT 250 WORDS)
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6

Hirano, Yoshiaki, Motoya Okuno, Toshio Hayashi, Kunio Goto, and Akio Nakajima. "Cell-attachment activities of surface immobilized oligopeptides RGD, RGDS, RGDV, RGDT, and YIGSR toward five cell lines." Journal of Biomaterials Science, Polymer Edition 4, no. 3 (1993): 235–43. http://dx.doi.org/10.1163/156856293x00546.

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7

Kouns, WC, D. Kirchhofer, P. Hadvary, et al. "Reversible conformational changes induced in glycoprotein IIb-IIIa by a potent and selective peptidomimetic inhibitor." Blood 80, no. 10 (1992): 2539–47. http://dx.doi.org/10.1182/blood.v80.10.2539.2539.

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Abstract Platelet glycoprotein (GP) IIb-IIIa inhibitors may become useful antithrombotic agents. Ro 4–5054 is a low molecular weight, noncyclic, peptidomimetic inhibitor that is three orders of magnitude more potent than RGDS in inhibiting fibrinogen binding to purified GPIIb-IIIa and in preventing platelet aggregation. Comparisons of RGDS and Ro 4–5054 in cell adhesion assays showed that, in contrast to RGDS, Ro 4–5054 was highly selective GPIIb-IIIa inhibitor. Effects of RGDV and Ro 4– 5054 on the conformation and activation state of GPIIb-IIIa were also examined. RGDV and Ro 4–5054 induced conformational changes in purified inactive GPIIb-IIIa as determined by binding of the monoclonal antibody D3GP3 (D3). These conformational alterations were not reversed after inhibitor removal, as indicated by the continued exposure of the D3 epitope and a newly acquired ability to bind fibrinogen. Similarly, RGDV and Ro 4–5054 induced conformational changes in GPIIb-IIIa on the intact platelet. However, after removal of the inhibitors, exposure of the D3 epitope was fully reversed and the platelets did not aggregate in the absence of agonist. Thus, while RGD(X) peptides and Ro 4–5054 transformed purified inactive GPIIb-IIIa into an irreversibly activated conformer, the effects of these inhibitors were reversible on the intact platelet. This suggests that factors present in the platelet membrane or cytoplasm may regulate in part the ability of the complex to shift between active and inactive conformers.
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8

Kouns, WC, D. Kirchhofer, P. Hadvary, et al. "Reversible conformational changes induced in glycoprotein IIb-IIIa by a potent and selective peptidomimetic inhibitor." Blood 80, no. 10 (1992): 2539–47. http://dx.doi.org/10.1182/blood.v80.10.2539.bloodjournal80102539.

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Platelet glycoprotein (GP) IIb-IIIa inhibitors may become useful antithrombotic agents. Ro 4–5054 is a low molecular weight, noncyclic, peptidomimetic inhibitor that is three orders of magnitude more potent than RGDS in inhibiting fibrinogen binding to purified GPIIb-IIIa and in preventing platelet aggregation. Comparisons of RGDS and Ro 4–5054 in cell adhesion assays showed that, in contrast to RGDS, Ro 4–5054 was highly selective GPIIb-IIIa inhibitor. Effects of RGDV and Ro 4– 5054 on the conformation and activation state of GPIIb-IIIa were also examined. RGDV and Ro 4–5054 induced conformational changes in purified inactive GPIIb-IIIa as determined by binding of the monoclonal antibody D3GP3 (D3). These conformational alterations were not reversed after inhibitor removal, as indicated by the continued exposure of the D3 epitope and a newly acquired ability to bind fibrinogen. Similarly, RGDV and Ro 4–5054 induced conformational changes in GPIIb-IIIa on the intact platelet. However, after removal of the inhibitors, exposure of the D3 epitope was fully reversed and the platelets did not aggregate in the absence of agonist. Thus, while RGD(X) peptides and Ro 4–5054 transformed purified inactive GPIIb-IIIa into an irreversibly activated conformer, the effects of these inhibitors were reversible on the intact platelet. This suggests that factors present in the platelet membrane or cytoplasm may regulate in part the ability of the complex to shift between active and inactive conformers.
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9

Lankhof, H., YP Wu, T. Vink, et al. "Role of the glycoprotein Ib-binding A1 repeat and the RGD sequence in platelet adhesion to human recombinant von Willebrand factor." Blood 86, no. 3 (1995): 1035–42. http://dx.doi.org/10.1182/blood.v86.3.1035.1035.

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Abstract To assess the relative importance of the glycoprotein (GP) Ib binding domain and the RGDS binding site in platelet adhesion to isolated von Willebrand factor (vWF) and to collagen preincubated with vWF, we deleted the A1 domain yielding delta A1-vWF and introduced an aspartate- to-glycine substitution in the RGDS sequence by site-directed mutagenesis (RGGS-vWF). Recombinant delta A1-vWF and RGGS-vWF, purified from transfected baby hamster kidney cells, were compared with recombinant wild-type vWF (WT-vWF) in platelet adhesion under static and flow conditions. Purified mutants were coated on glass or on a collagen type III surface and exposed to circulating blood in a perfusion system. Platelet adhesion under static condition, under flow conditions, and in vWF-dependent adhesion to collagen has an absolute requirement for GPIb-vWF interaction. The GPIIb/IIIa-vWF interaction is required for adhesion to coated vWF under flow conditions. Under static condition and vWF-dependent adhesion to collagen, platelet adhesion to RGGS-vWF is similar as to WT-vWF, but platelet spreading and aggregation are abolished.
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10

Lankhof, H., YP Wu, T. Vink, et al. "Role of the glycoprotein Ib-binding A1 repeat and the RGD sequence in platelet adhesion to human recombinant von Willebrand factor." Blood 86, no. 3 (1995): 1035–42. http://dx.doi.org/10.1182/blood.v86.3.1035.bloodjournal8631035.

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To assess the relative importance of the glycoprotein (GP) Ib binding domain and the RGDS binding site in platelet adhesion to isolated von Willebrand factor (vWF) and to collagen preincubated with vWF, we deleted the A1 domain yielding delta A1-vWF and introduced an aspartate- to-glycine substitution in the RGDS sequence by site-directed mutagenesis (RGGS-vWF). Recombinant delta A1-vWF and RGGS-vWF, purified from transfected baby hamster kidney cells, were compared with recombinant wild-type vWF (WT-vWF) in platelet adhesion under static and flow conditions. Purified mutants were coated on glass or on a collagen type III surface and exposed to circulating blood in a perfusion system. Platelet adhesion under static condition, under flow conditions, and in vWF-dependent adhesion to collagen has an absolute requirement for GPIb-vWF interaction. The GPIIb/IIIa-vWF interaction is required for adhesion to coated vWF under flow conditions. Under static condition and vWF-dependent adhesion to collagen, platelet adhesion to RGGS-vWF is similar as to WT-vWF, but platelet spreading and aggregation are abolished.
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11

Xie, Shuangfeng, Songmei Yin, Danian Nie, et al. "The Effects of Glycoprotein IIb/IIIa Antagonist RGDS on Platelet Aggregation and Release Reaction In Vitro." Blood 108, no. 11 (2006): 3908. http://dx.doi.org/10.1182/blood.v108.11.3908.3908.

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Abstract Platelet activation, including platelet adhesion, platelet aggregation and platelet release reaction, played an important role in thrombogenesis. We all knew that Platelet glycoprotein IIb/IIIa antagonist was the most effective drug for anti-aggregation, while we don’t know clearly its effect on platelet release reaction and the relations between its effects on platelet aggregation and release reaction. Platelet release reactions included α-granules and dense granules releasing. When α-granules were released, its membrane glycoprotein CD62p was expressed in the platelet membrane. We used the CD62p expression as the index of platelet release reaction. In the current study, the 4-peptides RGDS (Arg-Gly-Asp-Ser) was used as glycoprotein IIb/IIIa antagonist. We detected the effects of RGDS on platelet aggregation and CD62p expression induced by adenosine diphosphate (ADP) (finial concentration, 5μmol/L) in vitro. 50, 100, 200, 400 and 800μmol/L RGDS were used separately in the test. RGDS of each concentration could significantly inhibited maximal platelet aggregation (PAG(M)) induced by ADP, the 50% inhibiting concentration was approximately 200μmol/L. 800μmol/L RGDS could inhibited PAG(M) by 80.48±8.18%. Only ≥200μmol/L RGDS could significantly inhibited platelet CD62p expression. 800μmol/L RGDS could inhibit platelet CD62p expression by 27.31±9.74%. The inhibiting effect of RGDS on PAG(M) and platelet CD62p expression had significantly correlation (r =0.976, P<0.05). These results indicated that RGDS in low concentration (<200μmol) had little negative effect on platelet release reaction induced by ATP, while in relatively high concentration (≥200μmol) RGDS could inhibit platelet release reaction. When RGDS concentrations were same its effect on platelet release reaction was much less than that on platelet aggregation, which indicated that platelet glycoprotein IIb/IIIa compound could only partly participated in the platelet release reaction but fully participated in platelet aggregation induced by ADP.
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12

Donaldson, D. J., J. T. Mahan, and G. N. Smith. "Newt epidermal cell migration in vitro and in vivo appears to involve Arg-Gly-Asp-Ser receptors." Journal of Cell Science 87, no. 4 (1987): 525–34. http://dx.doi.org/10.1242/jcs.87.4.525.

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The effect of a synthetic peptide consisting of Arg-Gly-Asp-Ser (RGDS), the amino acid sequence representing the fibroblast attachment site in fibronectin (FN), was tested on migrating newt epidermal cells. In one approach, skin explants were placed on the bottom of plastic dishes coated with human FN, human fibrinogen (FGN), human serum spreading factor (SF), or bovine type I collagen. The explants were then incubated overnight in serum-free medium with or without RGDS. In these experiments exposure to 50 micrograms ml-1 of RGDS reduced migration over FN, FGN and SF to 2–7% of control levels. Two peptides structurally dissimilar to RGDS (Val-Gly-Ser-Glu and Thr-Pro-Arg-Lys), and two that are structurally similar (Lys-Gly-Asp-Ser and Arg-Gly-Glu-Ser), had no effect on explant migration even when used at concentrations higher than 50 micrograms ml-1. Upon removal of the RGDS peptide, inhibited explants quickly recovered. In collagen-coated dishes 50 micrograms ml-1 of RGDS was much less effective than in dishes coated with the other substrates. Raising the RGDS concentration in collagen-coated dishes tenfold did not greatly increase the RGDS effect. When added to the medium bathing wounded limbs, 50 micrograms ml-1 of RGDS only moderately inhibited wound closure. This concentration of peptide, however, severely inhibited migration from skin explants in newt-plasma-coated-dishes and migration over pieces of newt-plasma-coated plastic placed under one edge of a skin wound. Increasing the RGDS concentration to 500 micrograms ml-1 resulted in almost total suppression of wound closure. Wounds exposed to this same concentration of Lys-Gly-Asp-Ser closed normally. These results indicate that newt epidermal cells possess RGDS receptors and that these receptors are involved in epidermal wound closure in vivo and in migration from skin explants onto plastic coated with FN, FGN, SF and collagen. The relative RGDS-insensitivity of wound closure in vivo and in migration from explants onto collagen may reflect in these instances the presence of a relatively high density of RGDS receptor binding sites on the substrate; the presence of RGDS receptor binding sites of relatively high affinity; or the participation of receptors other than those involved in migration over plastic coated with FN, FGN or SF.
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13

Cox, Dermot, Toshiaki Aoki, Jiro Seki, Yukio Motoyama, and Keizo Yoshida. "Pentamidine Is a Specific, Non-Peptide, GPIIb/llla Antagonist." Thrombosis and Haemostasis 75, no. 03 (1996): 503–9. http://dx.doi.org/10.1055/s-0038-1650305.

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SummaryPentamidine was previously shown to act on glycoprotein (GP) Ilb/IIIa (Cox et al., Thromb Haemost 1992; 68: 731). In this paper we study the effect of pentamidine on other RGD-dependent receptors. In a cell adhesion assay, pentamidine was 500 times more potent than RGDS at inhibiting platelet adhesion to fibrinogen. While RGDS inhibited platelet adhesion to fibronectin, endothelial cell adhesion to vitronectin or fibronectin, 293 cell adhesion to vitronectin, IMR 32 cell adhesion to fibronectin and C32 cell adhesion to vitronectin; pentamidine failed to inhibit these interactions at doses as high as 1 mM. Resting platelets fixed in the presence of 1 mM RGDS had increased binding of fibrinogen, i.e., RGDS activated GPIMIIa, while pentamidine at 100 ΜM had no effect. Similarly, RGDS induced the binding of an anti-LIBS monoclonal antibody, while pentamidine had no effect. Pentamidine partially, but significantly, inhibited lysosome and a-granule release induced by the thrombin agonist peptide, while RGDS had no effect. Neither pentamidine nor RGDS affected ADP-induced Ca2+ influx. Pentamidine had no effect on ADP-induced intracellular pH changes while RGDS prevented the pH from returning to normal. Thus, pentamidine is a non-peptide GPIIb/IIIa antagonist that is non-activating and is specific for GPIIb/IIIa.
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14

Parker, RI, and HR Gralnick. "Inhibition of platelet-von Willebrand factor binding to platelets by adhesion site peptides." Blood 74, no. 4 (1989): 1226–30. http://dx.doi.org/10.1182/blood.v74.4.1226.1226.

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Abstract Synthetic peptides containing the adhesion site recognition sequences present on the A alpha and gamma chains of fibrinogen were studied for their effect on the binding of endogenous platelet-von Willebrand factor (vWF) and exogenous plasma-vWf to thrombin-stimulated platelets. In agreement with previously reported data, the tetrapeptide consisting of the RGDS sequence was a more potent inhibitor of plasma-vWf binding to platelets than was the pentadecapeptide of the carboxy terminus of the fibrinogen gamma-chain (IC50 10.6 mumol/L for the RGDS tetrapeptide v 44.9 mumol/L for the gamma-chain pentadecapeptide). No apparent synergy in the inhibition of plasma-vWf binding was noted when the RGDS and gamma-chain peptides were used together (IC50 15.2 mumol/L). In contrast, the gamma-chain peptide was significantly more inhibitory than was the RGDS tetrapeptide on the binding of platelet-vWf to platelets (IC50 1.4 mumol/L for the gamma-chain pentadecapeptide v 4.5 mumol/L for the RGDS tetrapeptide, P less than .05), and there was significant synergy in the inhibition of platelet-vWf binding noted when the gamma-chain and RGDS peptides were used together (IC50 0.04 mumol/L). These results indicate that the binding of platelet-vWf to its receptor on the platelet glycoprotein IIb/IIIa complex involves both the RGDS and gamma-chain recognition sites. In contrast to the results with plasma-vWf binding, the gamma-chain recognition site appears to be more important than the RGDS recognition site in platelet- vWf binding to platelets.
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15

Parker, RI, and HR Gralnick. "Inhibition of platelet-von Willebrand factor binding to platelets by adhesion site peptides." Blood 74, no. 4 (1989): 1226–30. http://dx.doi.org/10.1182/blood.v74.4.1226.bloodjournal7441226.

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Synthetic peptides containing the adhesion site recognition sequences present on the A alpha and gamma chains of fibrinogen were studied for their effect on the binding of endogenous platelet-von Willebrand factor (vWF) and exogenous plasma-vWf to thrombin-stimulated platelets. In agreement with previously reported data, the tetrapeptide consisting of the RGDS sequence was a more potent inhibitor of plasma-vWf binding to platelets than was the pentadecapeptide of the carboxy terminus of the fibrinogen gamma-chain (IC50 10.6 mumol/L for the RGDS tetrapeptide v 44.9 mumol/L for the gamma-chain pentadecapeptide). No apparent synergy in the inhibition of plasma-vWf binding was noted when the RGDS and gamma-chain peptides were used together (IC50 15.2 mumol/L). In contrast, the gamma-chain peptide was significantly more inhibitory than was the RGDS tetrapeptide on the binding of platelet-vWf to platelets (IC50 1.4 mumol/L for the gamma-chain pentadecapeptide v 4.5 mumol/L for the RGDS tetrapeptide, P less than .05), and there was significant synergy in the inhibition of platelet-vWf binding noted when the gamma-chain and RGDS peptides were used together (IC50 0.04 mumol/L). These results indicate that the binding of platelet-vWf to its receptor on the platelet glycoprotein IIb/IIIa complex involves both the RGDS and gamma-chain recognition sites. In contrast to the results with plasma-vWf binding, the gamma-chain recognition site appears to be more important than the RGDS recognition site in platelet- vWf binding to platelets.
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16

Wright, S. D., and B. C. Meyer. "Fibronectin receptor of human macrophages recognizes the sequence Arg-Gly-Asp-Ser." Journal of Experimental Medicine 162, no. 2 (1985): 762–67. http://dx.doi.org/10.1084/jem.162.2.762.

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When cultured human monocytes (MO) were spread on fibronectin (Fn)-coated surfaces, C3 receptors on the MO exhibited markedly enhanced capacity to promote phagocytosis. The activation of C3 receptors by Fn was mediated by a receptor that recognizes a sequence, Arg-Gly-Asp-Ser (RGDS), present in the cell-binding domain of Fn. Soluble, RGDS-containing peptides inhibited the activation of C3 receptors caused by surface-bound Fn, and surface-bound, RGDS-containing peptides themselves caused activation of the C3 receptors of attached MO. Although soluble, RGDS-containing peptides bound to Fn receptors, such monovalent ligation was insufficient to activate C3 receptors.
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17

Cui, Chunying, Yaonan Wang, Wen Zhao, et al. "RGDS covalently surfaced nanodiamond as a tumor targeting carrier of VEGF-siRNA: synthesis, characterization and bioassay." Journal of Materials Chemistry B 3, no. 48 (2015): 9260–68. http://dx.doi.org/10.1039/c5tb01602a.

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18

Thomas, D. D., J. B. Baseman, and J. F. Alderete. "Fibronectin tetrapeptide is target for syphilis spirochete cytadherence." Journal of Experimental Medicine 162, no. 5 (1985): 1715–19. http://dx.doi.org/10.1084/jem.162.5.1715.

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The syphilis bacterium, Treponema pallidum, parasitizes host cells through recognition of fibronectin (Fn) on cell surfaces. The active site of the Fn molecule has been identified as a four-amino acid sequence, arg-gly-asp-ser (RGDS), located on each monomer of the cell-binding domain. The synthetic heptapeptide gly-arg-gly-asp-ser-pro-cys (GRGDSPC), with the active site sequence RGDS, specifically competed with 125I-labeled cell-binding domain acquisition by T. pallidum. Additionally, the same heptapeptide with the RGDS sequence diminished treponemal attachment to HEp-2 and HT1080 cell monolayers. Related heptapeptides altered in one key amino acid within the RGDS sequence failed to inhibit Fn cell-binding domain acquisition or parasitism of host cells by T. pallidum. The data support the view that T. pallidum cytadherence of host cells is through recognition of the RGDS sequence also important for eukaryotic cell-Fn binding.
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19

Hantgan, RR, SC Endenburg, JJ Sixma, and PG de Groot. "Evidence that fibrin alpha-chain RGDX sequences are not required for platelet adhesion in flowing whole blood." Blood 86, no. 3 (1995): 1001–9. http://dx.doi.org/10.1182/blood.v86.3.1001.1001.

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Abstract The role of the RGDX putative receptor-recognition sites, which are present on the alpha chains of fibrin, in promoting platelet adhesion has been examined in flowing whole blood using the rectangular perfusion chamber at wall shear rates of 340 and 1,600/s. Platelets adhered to a comparable extent to surfaces coated with native fibrin and surfaces coated with fragment X-fibrin, a product of limited fibrinolysis that lacks the RGDS sites normally present at positions 572 to 575 of the alpha chains. The strengths of these adhesive interactions were comparable based on the concentrations of the antiadhesive peptide D-RGDW required to block platelet deposition to native and fragment X-fibrin at both low and high wall shear rate. Blocking either or both RGDX sequences with peptide-specific monoclonal antibodies did not inhibit platelet deposition in perfusion experiments performed with normal blood at 340/s, indicating that neither RGD motif is required for adhesion. However, adhesion was partly inhibited by anti-RGDX antibodies when perfusions were performed with blood from an afibrinogenemic patient, suggesting the RGDX sequences may play a limited role in platelet deposition. Exposure of fibrin surfaces to plasminogen/tissue-type plasminogen activator did cause a time- dependent loss of adhesiveness, but this effect was only weakly correlated with proteolysis of the fibrin alpha chains. These observations provide evidence that neither RGDX sequence is required for platelets to adhere avidly to fibrin in flowing blood. These results further suggest that incomplete fibrinolysis yields a highly thrombogenic surface.
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20

Hantgan, RR, SC Endenburg, JJ Sixma, and PG de Groot. "Evidence that fibrin alpha-chain RGDX sequences are not required for platelet adhesion in flowing whole blood." Blood 86, no. 3 (1995): 1001–9. http://dx.doi.org/10.1182/blood.v86.3.1001.bloodjournal8631001.

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The role of the RGDX putative receptor-recognition sites, which are present on the alpha chains of fibrin, in promoting platelet adhesion has been examined in flowing whole blood using the rectangular perfusion chamber at wall shear rates of 340 and 1,600/s. Platelets adhered to a comparable extent to surfaces coated with native fibrin and surfaces coated with fragment X-fibrin, a product of limited fibrinolysis that lacks the RGDS sites normally present at positions 572 to 575 of the alpha chains. The strengths of these adhesive interactions were comparable based on the concentrations of the antiadhesive peptide D-RGDW required to block platelet deposition to native and fragment X-fibrin at both low and high wall shear rate. Blocking either or both RGDX sequences with peptide-specific monoclonal antibodies did not inhibit platelet deposition in perfusion experiments performed with normal blood at 340/s, indicating that neither RGD motif is required for adhesion. However, adhesion was partly inhibited by anti-RGDX antibodies when perfusions were performed with blood from an afibrinogenemic patient, suggesting the RGDX sequences may play a limited role in platelet deposition. Exposure of fibrin surfaces to plasminogen/tissue-type plasminogen activator did cause a time- dependent loss of adhesiveness, but this effect was only weakly correlated with proteolysis of the fibrin alpha chains. These observations provide evidence that neither RGDX sequence is required for platelets to adhere avidly to fibrin in flowing blood. These results further suggest that incomplete fibrinolysis yields a highly thrombogenic surface.
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21

Wang, Peng, Lin Gui, Yuji Wang, and Sheng Wang. "In vitro evaluation of nanoparticle drug-coated balloons: a pectin-RGDS-OC8H17-paclitaxel solution." Applied Nanoscience 11, no. 4 (2021): 1339–47. http://dx.doi.org/10.1007/s13204-021-01736-4.

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AbstractDrug-coated balloons have proved to be an effective technology in percutaneous transluminal angioplasty in treating peripheral artery disease. Paclitaxel-based coating is mainly used. Solutions to such problems as drug loss and inefficient drug release during operations, however, have not been found yet. This study aims to explore the activity of a newly designed paclitaxel-coated balloon in vitro using pectin as the excipient (pectin-paclitaxel) compared with the commercially available shellac excipient balloon, and to characterize the novel nanoparticle paclitaxel-coated balloon with peptide (Arg-Gly-Asp-Ser, RGDS) derivative RGDS-OC8H17 (pectin-RGDS-OC8H17-paclitaxel). Two coating solutions, pectin-paclitaxel and pectin-RGDS-OC8H17-paclitaxel, were successively designed and prepared. The morphology of both coating solutions was first characterized compared with the control group, the commercially available paclitaxel-coated balloon. Then the in vitro experiments were conducted to determine the drug-releasing profiles of both pectin-paclitaxel and pectin-RGDS-OC8H17-paclitaxel coatings. The pectin-RGDS-OC8H17-paclitaxel-coated balloon was smoother and more homogeneous compared with the commercially available paclitaxel-coated balloon and the pectin-paclitaxel-coated balloon. This difference was more obvious when paclitaxel was at low concentration. During the in vitro trial, the drug-releasing curve of the pectin-RGDS-OC8H17-paclitaxel model showed an adjustable paclitaxel-releasing: more than 90% of the paclitaxel released in 2 h at 300 rpm and more than 99% released in 10 min at 1200 rpm. Compared to the performance of the current commercially available shellac excipient products and the pectin-paclitaxel coating, pectin-RGDS-OC8H17-paclitaxel coating provided higher drug-releasing speed. However, the clinical outcomes of this finding need to be further demonstrated. Paclitaxel-coated balloons as an effective therapeutic strategy currently in treating peripheral arterial disease need to be further improved in terms of its efficiency in anti-proliferative drug delivery and release. The pectin-RGDS-OC8H17-paclitaxel coating solution developed in this study exhibited excellent drug-releasing properties. Further experiments are still needed to demonstrate the performance of this novel drug-coated balloon in vivo and its clinical importance.
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22

Aguzzi, Maria Simona, Claudia Giampietri, Francesco De Marchis, et al. "RGDS peptide induces caspase 8 and caspase 9 activation in human endothelial cells." Blood 103, no. 11 (2004): 4180–87. http://dx.doi.org/10.1182/blood-2003-06-2144.

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Abstract Peptides containing the Arg-Gly-Asp (RGD) motif inhibit cell adhesion and exhibit a variety of other biologic effects including anticoagulant and antimetastatic activities. The aim of the present study was to examine the anchorage-independent effects of an RGD-containing peptide, Arg-Gly-Asp-Ser (RGDS), on human umbilical vein endothelial cells (HUVECs). Assays were performed on HUVECs seeded onto collagen IV; under these experimental conditions RGDS did not exert antiadhesive effects but significantly reduced FGF-2-dependent chemotaxis after 4 hours of treatment and reduced proliferation after 24 hours of treatment. Experiments carried out with caspase-specific inhibitors indicated that the observed antichemotactic effects required caspase 8 and caspase 9 activation. RGDS activated both caspase 8 and caspase 9 after 4 hours of treatment and caspase 3 after 24 hours of treatment, and markedly enhanced HUVEC apoptosis by transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)/Hoechst staining and fluorescence-activated cell sorting (FACS) analysis. Finally, confocal microscopy showed that RGDS localizes in the cytoplasm of live HUVECs within 4 hours and in vitro experiments showed that RGDS directly interacts with recombinant caspases 8 and 9 in a specific way. In summary, these results indicate that RGDS directly binds and activates caspases 8 and 9, inhibits chemotaxis, and induces apoptosis of HUVECs with a mechanism independent from its antiadhesive effect.
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23

Zanuy, David, Jordi Poater, Miquel Solà, Ian W. Hamley, and Carlos Alemán. "Fmoc–RGDS based fibrils: atomistic details of their hierarchical assembly." Physical Chemistry Chemical Physics 18, no. 2 (2016): 1265–78. http://dx.doi.org/10.1039/c5cp04269k.

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We describe the 3D supramolecular structure of Fmoc–RGDS fibrils, where Fmoc and RGDS refer to the hydrophobic N-(fluorenyl-9-methoxycarbonyl) group and the hydrophilic Arg-Gly-Asp-Ser peptide sequence, respectively.
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24

Mugnai, G., K. Lewandowska, B. Carnemolla, L. Zardi, and L. A. Culp. "Modulation of matrix adhesive responses of human neuroblastoma cells by neighboring sequences in the fibronectins." Journal of Cell Biology 106, no. 3 (1988): 931–43. http://dx.doi.org/10.1083/jcb.106.3.931.

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Attachment and neurite extension have been measured when Platt or La-N1 human neuroblastoma cells respond to tissue culture substrata coated with a panel of complementary fragments from the individual chains of human plasma (pFN) or cellular fibronectins (cFN) purified from thermolysin digests. A 110-kD fragment (f110), which contains the Arg-Gly-Asp-Ser sequence (RGDS)-dependent cell-binding domain but no heparin-binding domains and whose sequences are shared in common by both the alpha- and beta-subunits of pFN, facilitated attachment of cells that approached the level observed with either intact pFN or the heparan sulfate-binding platelet factor-4 (PF4). This attachment on f110 was resistant to RGDS-containing peptide in the medium. Neurite outgrowth was also maximal on f110, and half of these neurites were also resistant to soluble RGDS peptide. Treatment of cells with glycosaminoglycan lyases failed to alter these responses on f110. Therefore, there is a second "cell-binding" domain in the sequences represented by f110 that is not RGDS- or heparan sulfate-dependent and that facilitates stable attachment and some neurite outgrowth; this domain appears to be conformation-dependent. Comparisons were also made between two larger fragments generated from the two subunits of pFN-f145 from the alpha-subunit and f155 from the beta-subunit--both of which contain the RGDS-dependent cell-binding domain and the COOH-terminal heparin-binding domain but which differ in the former's containing some IIICS sequence at its COOH terminus and the latter's having an additional type III homology unit. Heparin-binding fragments (with no RGDS activity) of f29 and f38, derived from f145 or f155 of pFN, respectively, and having the same differences in sequence, were also compared with f44 + 47 having the "extra domain" characteristic of cFN. Attachment on f145 was slightly sensitive to soluble RGDS peptide; attachment on f155 was much more sensitive. There were also differences in the percentage of cells with neurites on f145 vs. f155 but neurites on either fragment were completely sensitive to RGDS peptide. Mixing of f29, f38, or PF4 with f110 could not reconstitute the activities demonstrated in f145 or f155, demonstrating that covalently linked sequences are critical in modulating these responses. However, mixing of f44 + 47 from cFN with f110 from pFN increased the sensitivity to RGDS peptide.(ABSTRACT TRUNCATED AT 400 WORDS)
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25

Peerschke, EI, and DK Galanakis. "The synthetic RGDS peptide inhibits the binding of fibrinogen lacking intact alpha chain carboxyterminal sequences to human blood platelets." Blood 69, no. 3 (1987): 950–52. http://dx.doi.org/10.1182/blood.v69.3.950.950.

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Abstract The alpha chain 572–574 Arg-Gly-Asp sequence of fibrinogen appears to play only a minor role in platelet aggregation based on the ability of fibrinogen preparations lacking alpha chain carboxyterminal segments to support platelet aggregation, but synthetic Arg-Gly-Asp-Ser (RGDS) peptides are capable of inhibiting platelet aggregation and fibrinogen binding. The present study thus examined the ability of RGDS peptides to inhibit platelet interactions with a plasmic degradation product of fibrinogen (8D–50) that resembles an intermediate fragment X. Gel- filtered, human blood platelets suspended in 0.01 mol/L HEPES-buffered modified Tyrode's solution, pH 7.5, were stimulated with 20 mumol/L adenosine diphosphate and the binding of 125I-labeled 8D–50 or intact fibrinogen (0.01 to 0.6 mg/mL) assessed in the presence of 0 to 117 mumol/L RGDS. The data revealed that RGDS decreased the apparent affinity of 8D–50 and intact fibrinogen for platelets but did not affect the maximum number of binding sites. RGDS thus appears to be a competitive inhibitor not only of intact fibrinogen (Ki = 12 +/- 2 mumol/L) but also of 8D–50 (Ki = 15 +/- 3 mumol/L) (mean +/- SD, n = 3).
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26

Peerschke, EI, and DK Galanakis. "The synthetic RGDS peptide inhibits the binding of fibrinogen lacking intact alpha chain carboxyterminal sequences to human blood platelets." Blood 69, no. 3 (1987): 950–52. http://dx.doi.org/10.1182/blood.v69.3.950.bloodjournal693950.

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The alpha chain 572–574 Arg-Gly-Asp sequence of fibrinogen appears to play only a minor role in platelet aggregation based on the ability of fibrinogen preparations lacking alpha chain carboxyterminal segments to support platelet aggregation, but synthetic Arg-Gly-Asp-Ser (RGDS) peptides are capable of inhibiting platelet aggregation and fibrinogen binding. The present study thus examined the ability of RGDS peptides to inhibit platelet interactions with a plasmic degradation product of fibrinogen (8D–50) that resembles an intermediate fragment X. Gel- filtered, human blood platelets suspended in 0.01 mol/L HEPES-buffered modified Tyrode's solution, pH 7.5, were stimulated with 20 mumol/L adenosine diphosphate and the binding of 125I-labeled 8D–50 or intact fibrinogen (0.01 to 0.6 mg/mL) assessed in the presence of 0 to 117 mumol/L RGDS. The data revealed that RGDS decreased the apparent affinity of 8D–50 and intact fibrinogen for platelets but did not affect the maximum number of binding sites. RGDS thus appears to be a competitive inhibitor not only of intact fibrinogen (Ki = 12 +/- 2 mumol/L) but also of 8D–50 (Ki = 15 +/- 3 mumol/L) (mean +/- SD, n = 3).
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27

Choi, Moon-Jeong, R. Pierson, Yongmin Chang, Haiquing Guo, and Inn-Kyu Kang. "Enhanced Intracellular Uptake of CdTe Quantum Dots by Conjugation of Oligopeptides." Journal of Nanomaterials 2013 (2013): 1–8. http://dx.doi.org/10.1155/2013/291020.

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Arg-Gly-Asp-Ser (RGDS), a typical membrane-permeable carrier peptide, was conjugated with mercaptoisobutyric acid-immobilized CdTe quantum dot (CTNPs) to enhance the intracellular uptake of quantum dots. Mean size of mercaptoisobutyric acid-immobilized quantum dots (37 nm) as determined by dynamic light scattering was increased up to 54 nm after RGDS immobilization. It was found, fromin vitrocell culture experiment, that fibroblast (NIH 3T3) cells were well proliferated in the presence of RGDS-conjugated quantum dots (RCTNPs), and the intracellular uptake of CTNPs and RCTNPs was studied by means of ICP and fluorescence microscopy. As a result, the RCTNPs specifically bound to the membrane of NIH 3T3 cells and almost saturated after 6 hours incubation. The amount of RCTNPs uptaken by the cells was higher than that of CTNPs, demonstrating the enhancing effect of RGDS peptide conjugation on the intracellular uptake of quantum dots (QDs).
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28

Mouguelar, Valeria S., Marcelo O. Cabada, and Gabriela Coux. "The integrin-binding motif RGDS induces protein tyrosine phosphorylation without activation in Bufo arenarum (Amphibia) oocytes." REPRODUCTION 141, no. 5 (2011): 581–93. http://dx.doi.org/10.1530/rep-10-0411.

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Integrins are cell adhesion molecules that are thought to be involved in sperm–oocyte interaction. Nevertheless, their function in mammalian fertilization is still controversial, as different species behave differently. In amphibians, their role is mainly supported byXenopus laevisstudies, where RGDS peptide induces oocyte activation. We recently provided evidence suggesting the presence and involvement of integrins in the interaction of the oocyte plasma membrane (PM) with sperm in the amphibianBufo arenarum. In order to understand the role of integrin homologs in oocytes and their possible contribution to egg activation mechanisms, we examined the presence of integrin subunits and the effect of RGDS peptide on oocytes and during fertilization. Western blot studies detected integrin subunits α5, αV and β1 in oocytes. In sperm, we could detect only the αV integrin subunit. We found that RGDS peptide was unable to elicit egg activation or MAPK dephosphorylation, but can induce reversible inhibition of fertilization. A similar partial inhibition was produced by an anti-β1 integrin antibody. Using an anti-phosphotyrosine antibody we found major changes in phosphotyrosine-containing proteins in egg extracts minutes after fertilization. Cytosol and PMs isolated from oocytes and fertilized eggs showed additional fertilization-induced phosphorylated proteins. Some of these were also present in cytosol and PMs from RGDS-treated oocytes (partially mimicking fertilization). These findings suggest thatB. arenarumfertilization involves integrins (e.g. β1 subunit) as adhesion proteins. Our data support the view that RGDS-binding receptors may function as signaling receptors inB. arenarumoocytes, but integrin engagement by RGDS is not sufficient for oocyte activation.
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29

Yin, Songmei, Yiqing Li, Shuangfeng Xie, et al. "The Effects of Glycoprotein IIb/IIIa Antagonists and Chloride Channel Blockers on Platelet Cytoplasmic Free Calcium." Blood 106, no. 11 (2005): 3939. http://dx.doi.org/10.1182/blood.v106.11.3939.3939.

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Abstract Objective To explore the effects and interactions of GPIIb/IIIa antagonists and chloride channel blockers on the platelet cytoplasmic free calcium ([Ca2+]i ). Methods We washed and suspended fresh platelets with Hepes buffer containing 0.1% bovine serum albumin (BSA), then loaded platelets with 5μmol/L Fura-3/AM. Then RGDS, the GPIIb/IIIa antagonists, and the chloride channel blockers 4,4′-diisothiocyano-2,2′-disulfonic acid stilbene(DIDS) or niflumic acid(NFA) were added to the platelet suspension. After 2 minutes incubating, we observed the effects and interactions of GPIIb/IIIa antagonists and chloride channel blockers on platelet [Ca2+]i by measuring the Fura-3 fluorescence intensity. Results 1. Effects of GPIIb/IIIa antagonists and chloride channel blockers on platelet [Ca2+]i. The fluorescence intensity of resting platelet [Ca2+]i were 369.6±62.2, 381.9±72.4, 392.8 ±69.9 after adding RGDS(250 μmol/L), DIDS(100 μmol/L) or NFA( 100 μmol/L) respectively. every agent had no significant effect on resting [Ca2+]i (p>0.05). After thrombin(0.03 U/ml) stimulating and adding RGDS(250 μmol/L), DIDS(100 μmol/L) or NFA( 100 μmol/L), the platelet [Ca2+]i were 883.9±107.0, 789.8±99.8, 564.1±79.4. Compare with the control(977.9±108.8), the three agents could inhibit the elevation of [Ca2+]i stimulated by thrombin (p<0.05). The inhibiting rates were (9.37±7.5)%, (18.7±10.4)% and (41.8±10.1)% respectively. 2. Combined effects of GPIIb/IIIa antagonists and chloride channel blockers The fluorescence intensity of resting platelet [Ca2+]i was 383.9±67.9 after incubated with RGDS and DIDS. That had no significant effects. When platelets were stimulated by thrombin (0.03 U/ml), the combined inhibition rate was (24.4±10.8)%, RGDS and DIDS couldn’t weaken or enhance each other on thrombin-induced elevation of [Ca2+]i (p>0.05). Neither RGDS nor NFA had significant combined effects on resting [Ca2+]i(p>0.05). The combined inhibition rate was (46.0±7.3)%, they had no interactions too(p>0.05). Conclusion The GPIIb/IIIa antagonists RGDS and the chloride channel blockers DIDS or NFA have no effect on resting platelet [Ca2+]i. All of them can inhibit the elevation of platelet [Ca2+]i induced by thrombin. There are no interactions between GPIIb/IIIa antagonists RGDS and chloride channel blockers (DIDS or NFA) in resting platelet [Ca2+]i and elevation of platelet [Ca2+]i induced by thrombin, and their effects were independent.
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30

Harfenist, EJ, MA Packham, and JF Mustard. "Effects of the cell adhesion peptide, Arg-Gly-Asp-Ser, on responses of washed platelets from humans, rabbits, and rats." Blood 71, no. 1 (1988): 132–36. http://dx.doi.org/10.1182/blood.v71.1.132.132.

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Abstract Fibrinogen is a cofactor in the aggregation of human platelets, and is required for ADP-induced aggregation of washed platelets; however, exogenous fibrinogen is not required for ADP-induced aggregation of washed platelets from rabbits or rats. Because with human platelets the cell adhesion peptide, Arg-Gly-Asp-Ser (RGDS), inhibits aggregation and the binding of 125I-fibrinogen to ADP-stimulated platelets, its effects on rabbit and rat platelets were studied to investigate the differences in the fibrinogen requirements of platelets from the three species. RGDS (50 mumol/L) caused greater than 80% inhibition of thrombin- induced or (ADP + fibrinogen)-induced aggregation of human platelets, but only 3% to 9% inhibition of the aggregation of rabbit or rat platelets, regardless of whether fibrinogen was added. RGDS inhibited the binding of 125I-fibrinogen to ADP-stimulated human platelets by 80% to 90%, but by only 15% to 27% in the case of rabbit or rat platelets. The differences were due to the species of platelets, since human and rabbit fibrinogens gave similar results. In addition, RGDS failed to displace fibrinogen from the surface of rabbit platelets that had been stimulated with ADP. Thus, there are species differences in the ability of the cell adhesion peptide, RGDS, to block the platelet fibrinogen receptor, even within the mammalian species.
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31

Harfenist, EJ, MA Packham, and JF Mustard. "Effects of the cell adhesion peptide, Arg-Gly-Asp-Ser, on responses of washed platelets from humans, rabbits, and rats." Blood 71, no. 1 (1988): 132–36. http://dx.doi.org/10.1182/blood.v71.1.132.bloodjournal711132.

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Fibrinogen is a cofactor in the aggregation of human platelets, and is required for ADP-induced aggregation of washed platelets; however, exogenous fibrinogen is not required for ADP-induced aggregation of washed platelets from rabbits or rats. Because with human platelets the cell adhesion peptide, Arg-Gly-Asp-Ser (RGDS), inhibits aggregation and the binding of 125I-fibrinogen to ADP-stimulated platelets, its effects on rabbit and rat platelets were studied to investigate the differences in the fibrinogen requirements of platelets from the three species. RGDS (50 mumol/L) caused greater than 80% inhibition of thrombin- induced or (ADP + fibrinogen)-induced aggregation of human platelets, but only 3% to 9% inhibition of the aggregation of rabbit or rat platelets, regardless of whether fibrinogen was added. RGDS inhibited the binding of 125I-fibrinogen to ADP-stimulated human platelets by 80% to 90%, but by only 15% to 27% in the case of rabbit or rat platelets. The differences were due to the species of platelets, since human and rabbit fibrinogens gave similar results. In addition, RGDS failed to displace fibrinogen from the surface of rabbit platelets that had been stimulated with ADP. Thus, there are species differences in the ability of the cell adhesion peptide, RGDS, to block the platelet fibrinogen receptor, even within the mammalian species.
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32

Hill, D. J., and A. F. Rowley. "Are integrins involved in the aggregatory and phagocytic behaviour of fish haemostatic cells?" Journal of Experimental Biology 201, no. 4 (1998): 599–608. http://dx.doi.org/10.1242/jeb.201.4.599.

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The involvement of a putative integrin-like fibrinogen receptor in the aggregatory and phagocytic behaviour of thrombocytes (platelet equivalents of fish) from the rainbow trout Oncorhynchus mykiss was studied. Aggregation of trout thrombocytes was induced by the thromboxane mimetic U-46619 in the presence of trout fibrinogen. Thrombocyte aggregation was inhibited by the tetrapeptide RGDS, but not by RGES or fibrinogen binding inhibitor peptide (HHLGGAKQAGDV). A range of monoclonal antibodies against the human platelet integrin alphaIIbbeta3 (anti-CD41a, anti-beta3 and LK7r) showed no reactivity with trout thrombocytes. Subsequently, a panel of monoclonal antibodies was raised against thrombocyte membrane preparations in an attempt to obtain an antibody against the putative integrin fibrinogen receptor. Of these monoclonal antibodies, four were found to inhibit thrombocyte aggregation, namely 12G2, 30D8, 32F8 and 32H10. The antibody 32H10 was shown significantly to inhibit the attachment of thrombocytes to immobilised trout fibrinogen, suggesting that it and the other antibodies recognise the putative fibrinogen receptor on trout thrombocytes. FITC-labelled Bacillus cereus were employed as test particles to prove that thrombocytes internalise bacteria via an active process and not simply by passive sequestration into the open canalicular system. Preincubation of bacteria with trout fibrinogen resulted in a significant increase in the number of thrombocytes exhibiting phagocytosis. This enhancement of phagocytosis by preincubation of B. cereus with trout fibrinogen could be inhibited by the tetrapeptide RGDS, but not by RGES, hence implicating the putative fibrinogen receptor in the internalisation of microorganisms. The relevance of these findings to the possible existence of an integrin-like receptor on trout thrombocytes is discussed.
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33

Qian, Bin, Yingqing Sun, Yan Guo, Xin Dang, and Binggen Ru. "A prourokinase-RGDS chimera." Science in China Series C: Life Sciences 42, no. 3 (1999): 259–66. http://dx.doi.org/10.1007/bf03183601.

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34

Fu, Ya, Meina Huang, Yanfeng Luo, Chengbo Hu, and Yuanliang Wang. "Studying the Effective Concentration of RGDS on RGDS-Poly(DL-Lactic Acid)." Asian Journal of Chemistry 25, no. 2 (2013): 763–66. http://dx.doi.org/10.14233/ajchem.2013.12878.

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35

Fressinaud, Edith, Jean Pierre Girma, J. Evan Sadler, Hans R. Baumgartner, and Dominique Meyer. "Synthetic RGDS-Containing Peptides of von Willebrand Factor Inhibit Platelet Adhesion to Collagen." Thrombosis and Haemostasis 64, no. 04 (1990): 589–93. http://dx.doi.org/10.1055/s-0038-1647363.

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SummaryWe compared the effect of a synthetic dodecapeptide of residues 400-411 of the Γ chain of fibrinogen (Γ Fg 400-411) and of three synthetic peptides (15 to 18 aminoacids), of human von Willebrand Factor (vWF), containing the 1744-1747 Arg-Gly-Asp-Ser (RGDS) sequence, upon platelet adhesion to collagen in flowing blood. Both types of peptides are known to inhibit the binding of adhesive proteins to platelet membrane glycoprotein Ilb/IIIa (GPIIb/IIIa). Collagen was coated onto plastic cover slips and exposed in parallel-plate perfusion chambers to reconstituted human blood at various shear rates for 5 min at 37 °C. At a shear rate of 2,600 s−1, RGDS peptides inhibited platelet adhesion to collagen in a dose-dependent manner and appeared to be more potent inhibitors than the Γ Fg 400-411 on a molar basis. No synergetic effect between RGDS and Γ Fg 400-411 peptides was observed. These results suggest that the RGDS peptides affect adhesion by inhibiting the GPIIb/IIIa-vWF interaction and confirm the involvement of this platelet receptor in vWF-mediated platelet adhesion to collagen at high shear rate.
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36

Zhou, Xuejun, Wenxiong Huang, Jie Li, and Ding Chen. "Robust Geotechnical Design for Soil Slopes considering Uncertain Parameters." Mathematical Problems in Engineering 2020 (March 16, 2020): 1–11. http://dx.doi.org/10.1155/2020/5190580.

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Designing the geometry of soil slope is an effective treatment for preventing slope failure. How to deal with the uncertainties involved in soil parameters in geotechnical design is a main concern of geotechnical engineers. In this study, a robust geotechnical design for soil slopes (RGDS) approach was proposed, in which the Uncertainty Theory was introduced to describe explicitly the uncertainties involved in soil parameters. The uncertain reliability is often used to describe the risk of slope failure. The design robustness describing the insensitivity between the variation in the system response and the variation of input uncertain soil parameters was evaluated by the signal-to-noise ratio. The objectives of this design are to maximize the design robustness, minimize the excavation cost, and guarantee the safety (maximize the uncertain reliability). Therefore, the RGDS was formulated as a multiobjective optimization, and the optimal design can be determined based on the concepts of Pareto front and knee point. The proposed RGDS approach was illustrated through a numerical case of a two-layer slope design. The numerical results indicate that the RGDS approach is not only more intuitive and easier to follow but also more computationally efficient.
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37

Lewandowska, K., E. Balza, L. Zardi, and L. A. Culp. "Requirement for two different cell-binding domains in fibronectin for neurite extension of neuronal derivative cells." Journal of Cell Science 95, no. 1 (1990): 75–83. http://dx.doi.org/10.1242/jcs.95.1.75.

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Some neuron-derived cells, such as neuroblastoma cells, adhere and extend neurites on fibronectin (FN) substrata by processes that can be independent of binding to the Arg-Gly-Asp-Ser sequence (RGDS in FN) and independent of proteoglycan/ganglioside-binding activities of FN. Proteolytic fragments of various FNs have been used in this study to map a new adhesion-promoting domain in FNs that may be neural cell-specific. A thermolysin-generated fragment of human plasma FN (F110 containing the RGDS domain) or the analagous fragment from transformed human cell FN (F120, also containing the alternately spliced extra domain b[EDb]) facilitate RGDS-independent adherence and neurite extension of human neuroblastoma cells and an F11 hybrid neuronal line (by fusion of mouse neuroblastoma cells with rat dorsal root ganglion neurons) as effectively as adherence and neurite extension on intact FN. Since neither F110 nor F120 contains sequences from the alternately spliced IIICS region of FN, neurite-promoting activity in these fragments cannot be ascribed to a recently discovered cell-binding domain in this region. Furthermore, F120 could be cleaved into two subfragments retaining virtually all the sequence of the parent fragment: F35 from the C terminus of F120 containing the RGDS domain, and F90 from the N terminus containing most of the EDb region bordering the thermolysin cleavage site. These neuronal cells could adhere but not extend neurites on substrata coated with either F35 or F90 alone while 3T3 cells could adhere only on F35. Mixtures of F35 and F90 on substrata could reconstitute some, but not nearly all, of the neurite-promoting activity of F120. Therefore, these data identify a new cell-binding domain in common sequences of FNs on the N-terminal side of EDb and demonstrate cooperativity between this RGDS-independent domain and the RGDS-dependent domain for maximal differentiation of these neuron-derived cells. Several possibilities for a receptor directed to this new domain are discussed.
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38

Nakatani, Shingo, Takaaki Hato, Yoko Minamoto, and Shigeru Fujita. "Differential Inhibition of Fibrinogen Binding to Agonist-and RGDS Peptide-activated States of GPIIb-IIIa by an anti-GPIIIa Monoclonal Antibody, PMA5." Thrombosis and Haemostasis 76, no. 06 (1996): 1030–37. http://dx.doi.org/10.1055/s-0038-1650703.

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SummaryPlatelet agonists and RGD-containing peptides can convert platelet membrane glycoprotein (GP) Ilb-IIIa from its resting state to an activated state competent to bind soluble fibrinogen. We examined the effects of two anti-GPIIb-IIIa monoclonal antibodies, PMA1 and PMA5, on fibrinogen binding to agonist- and RGD-activated GPIIb-IIIa. PMA1 abolished aggregation of both agonist- and RGDS peptide-activated fixed platelets, and inhibited the binding of 125I-fibrinogen to these platelets almost completely. PMA5 had the same effects on agonist-activated platelets, but had little effect on the aggregation of RGDS-activated fixed platelets, and inhibited fibrinogen binding to RGDS-activated fixed platelets by only 44%. PMA5 bound to agonist- and RGDS-activated platelets equally. Immunoblot analysis showed that PMA5 bound to intact GPIIIa, but not to a 66 kDa fragment of GPIIIa digested by chymotrypsin. Although PMA5 inhibited platelet adhesion to immobilized fibrinogen by 94%, 44% of the remaining adherent platelets were spread. In contrast, no platelet spreading was observed in the presence of PMA1. These findings indicate that PMA5 is a novel anti-GPIIIa monoclonal antibody with the ability to inhibit fibrinogen binding to agonist- and RGD-activated states of GPIIb-IIIa differentially, and suggest that binding of immobilized fibrinogen to RGD-activated GPIIb-IIIa is necessary for platelet spreading.
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39

Simms, H., and R. D'Amica. "Matrix protein regulation of PMN oxidative metabolism during ischemia." American Journal of Physiology-Cell Physiology 266, no. 3 (1994): C637—C647. http://dx.doi.org/10.1152/ajpcell.1994.266.3.c637.

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Matrix proteins upregulate polymorphonuclear neutrophil (PMN) oxidative metabolism in a normoxic environment. We sought to investigate the relationship between matrix proteins and adherent PMN oxidative metabolism during acute ischemia. PMN adherent to buffer, fibronectin, Arg-Gly-Asp-Ser (RGDS), or laminin were placed in either normoxic or ischemic media. PMN adherence, superoxide anion production, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) formazan production, and surface receptor expression (CD64, CD32w, CD16, CD35, and CD11b/CD18) using monoclonal antibodies directed against these receptors were assayed. Ischemia increased PMN adherence unless the PMN were adhered to fibronectin or RGDS. Ischemia reduced PMN superoxide anion, MTT formazan, and H2O2 production unless the PMN were adhered to fibronectin or RGDS. Fibronectin and RGDS prevented ischemic-induced suppression of FcR expression. Immunofluorescent studies demonstrated capping and clustering of PMN Fc and complement receptors during ischemia while adhered on matrix proteins. These results demonstrate that 1) ischemia suppresses matrix protein upregulation of PMN oxidative metabolism, which is restored by fibronectin; 2) fibronectin-mediated restoration of PMN oxidative metabolism involves the binding epitope of fibronectin; and 3) fibronectin maintains PMN oxidative metabolism during ischemia in part by maintaining PMN FcR on the cell surface and by recruiting a new population of PMN capable of undergoing oxidative metabolism.
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40

Brown, A. J., and E. J. Sanders. "Interactions between mesoderm cells and the extracellular matrix following gastrulation in the chick embryo." Journal of Cell Science 99, no. 2 (1991): 431–41. http://dx.doi.org/10.1242/jcs.99.2.431.

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In the gastrulating chick embryo, the mesoderm cells arise from the epiblast layer by ingression through the linear accumulation of cells called the primitive streak. The mesoderm cells emerge from the streak with a fibroblastic morphology and proceed to move away from the mid-line of the embryo using, as a substratum, the basement membrane of the overlying epiblast and the extracellular matrix. We have investigated the roles of fibronectin and laminin as putative substrata for mesoderm cells using complementary in vivo and in vitro methods. We have microinjected agents into the tissue space adjacent to the primitive streak of living embryos and, after further incubation, we have examined the embryos for perturbation of the mesoderm tissue. These agents were: cell-binding regions from fibronectin (RGDS) and laminin (YIGSR), antibodies to these glycoproteins, and a Fab' fragment of the antibody to fibronectin. We find that RGDS, antibody to fibronectin, and the Fab' fragment cause a decrease in the number of mesoderm cells spread on the basement membrane, and a perturbation of cell shape suggesting locomotory impairment. No such influence was seen with YIGSR or antibodies to laminin. These results were extended using in vitro methods in which mesoderm cells were cultured in fibronectin-free medium on fibronectin or laminin in the presence of various agents. These agents were: RGDS; YIGSR; antibodies to fibronectin, fibronectin receptor, laminin and vitronectin; and a Fab' fragment of the fibronectin antiserum. We find that cell attachment and spreading on fibronectin is impaired by RGDS, antiserum to fibronectin, the Fab' fragment of fibronectin antiserum, and antiserum to fibronectin receptor. The results suggest that although the RGDS site in fibronectin is important, it is probably not the only fibronectin cell-binding site involved in mediating the behaviour of the mesoderm cells. Cells growing on laminin were perturbed by YIGSR, RGDS and antibodies to laminin, suggesting that mesoderm cells are able to recognise at least two sites in the laminin molecule. We conclude that the in vivo dependence of mesoderm cells on fibronectin is confirmed, but that although these cells have the ability to recognise sites in laminin as mediators of attachment and spreading, the in vivo role of this molecule in mesoderm morphogenesis is not yet certain.
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41

Hartley, Taila, Gabrielle Lemire, Kristin D. Kernohan, Heather E. Howley, David R. Adams, and Kym M. Boycott. "New Diagnostic Approaches for Undiagnosed Rare Genetic Diseases." Annual Review of Genomics and Human Genetics 21, no. 1 (2020): 351–72. http://dx.doi.org/10.1146/annurev-genom-083118-015345.

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Accurate diagnosis is the cornerstone of medicine; it is essential for informed care and promoting patient and family well-being. However, families with a rare genetic disease (RGD) often spend more than five years on a diagnostic odyssey of specialist visits and invasive testing that is lengthy, costly, and often futile, as 50% of patients do not receive a molecular diagnosis. The current diagnostic paradigm is not well designed for RGDs, especially for patients who remain undiagnosed after the initial set of investigations, and thus requires an expansion of approaches in the clinic. Leveraging opportunities to participate in research programs that utilize new technologies to understand RGDs is an important path forward for patients seeking a diagnosis. Given recent advancements in such technologies and international initiatives, the prospect of identifying a molecular diagnosis for all patients with RGDs has never been so attainable, but achieving this goal will require global cooperation at an unprecedented scale.
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42

Rogers, S. L., P. C. Letourneau, B. A. Peterson, L. T. Furcht, and J. B. McCarthy. "Selective interaction of peripheral and central nervous system cells with two distinct cell-binding domains of fibronectin." Journal of Cell Biology 105, no. 3 (1987): 1435–42. http://dx.doi.org/10.1083/jcb.105.3.1435.

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Mechanisms of cell interaction with fibronectin have been studied with proteolytic fibronectin fragments that have well-defined ligand binding properties. Results of a previous study (Rogers, S. L., J. B. McCarthy, S. L. Palm, L. T. Furcht, and P. C. Letourneau, 1985, J. Neurosci., 5:369-378) demonstrated that (a) central (CNS) and peripheral (PNS) nervous system neurons adhere to, and extend neurites on a 33-kD carboxyl terminal fibronectin fragment that also binds heparin, and (b) neurons from the PNS, but not the CNS, have stable interactions with a 75-kD cell-binding fragment and with intact fibronectin. In the present study domain-specific reagents were used in inhibition assays to further differentiate cell surface interactions with the two fibronectin domains, and to define the significance of these domains to cell interactions with the intact fibronectin molecule. These reagents are (a) a soluble synthetic tetrapeptide Arg-Gly-Asp-Ser (RGDS; Pierschbacher, M. D., and E. Ruoslahti, 1984, Nature (Lond.), 309:30-33) representing a cell-binding determinant in the 75-kD fragment, and (b) an antibody raised against the 33-kD fragment that binds specifically to that fragment. Initial cell attachment to, and neurite extension upon, fibronectin and the two different fragments was evaluated in the presence and absence of the two reagents. Attachment of both PNS and CNS cells to intact fibronectin was reduced in the presence of RGDS, the former more so than the latter. In contrast, the antibody to the 33-kD fragment did not affect attachment of PNS cells to fibronectin, but significantly decreased attachment of CNS cells to the molecule. RGDS inhibited attachment of CNS cells to the molecule. RGDS inhibited attachment of both cell types to the 75-kD fragment to a greater degree than it did attachment to the intact molecule. Cell interaction with the 33-kD fragment was not affected by RGDS. Reduction of neurite lengths (determined after 24 h of culture) by the domain-specific reagents paralleled the reduction in initial adhesion to each substratum. Therefore, it appears that (a) both PNS and CNS cells have receptors for each cell-binding domain of fibronectin, (b) the receptor(s) for the two domains are distinct, with attachment to the 33-kD fragment being independent of RGDS, and (c) the relative importance of each domain to cell interaction with intact fibronectin is different for CNS and PNS cells.
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43

Svozilová, Hana, Zdeněk Plichta, Vladimír Proks, et al. "RGDS-Modified Superporous Poly(2-Hydroxyethyl Methacrylate)-Based Scaffolds as 3D In Vitro Leukemia Model." International Journal of Molecular Sciences 22, no. 5 (2021): 2376. http://dx.doi.org/10.3390/ijms22052376.

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Superporous poly(2-hydroxyethyl methacrylate-co-2-aminoethyl methacrylate) (P(HEMA-AEMA)) hydrogel scaffolds are designed for in vitro 3D culturing of leukemic B cells. Hydrogel porosity, which influences cell functions and growth, is introduced by adding ammonium oxalate needle-like crystals in the polymerization mixture. To improve cell vitality, cell-adhesive Arg-Gly-Asp-Ser (RGDS) peptide is immobilized on the N-(γ-maleimidobutyryloxy)succinimide-activated P(HEMA-AEMA) hydrogels via reaction of SH with maleimide groups. This modification is especially suitable for the survival of primary chronic lymphocytic leukemia cells (B-CLLs) in 3D cell culture. No other tested stimuli (interleukin-4, CD40 ligand, or shaking) can further improve B-CLL survival or metabolic activity. Both unmodified and RGDS-modified P(HEMA-AEMA) scaffolds serve as a long-term (70 days) 3D culture platforms for HS-5 and M2-10B4 bone marrow stromal cell lines and MEC-1 and HG-3 B-CLL cell lines, although the adherent cells retain their physiological morphologies, preferably on RGDS-modified hydrogels. Moreover, the porosity of hydrogels allows direct cell lysis, followed by efficient DNA isolation from the 3D-cultured cells. P(HEMA-AEMA)-RGDS thus serves as a suitable 3D in vitro leukemia model that enables molecular and metabolic assays and allows imaging of cell morphology, interactions, and migration by confocal microscopy. Such applications can prospectively assist in testing of drugs to treat this frequently recurring or refractory cancer.
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44

Schaffner-Reckinger, Elisabeth, Nicolaas Brons та Nelly Kieffer. "Evidence from Site-directed Mutagenesis that the Cytoplasmic Domain of the β3 Subunit Influences the Conformational State of the αvβ3 Integrin Ectodomain". Thrombosis and Haemostasis 85, № 04 (2001): 716–23. http://dx.doi.org/10.1055/s-0037-1615658.

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SummaryIn order to explore the mechanisms leading to conformational changes of the vitronectin receptor αvβ3 following ligand or divalent cation binding, we have investigated the expression of epitopes known as ligand-induced binding sites (LIBS) on 3 cytoplasmic tail mutants expressed in CHO cells. Truncation of the entire 3 cytoplasmic domain induced constitutive LIBS exposure on αvβ3 and IIb β3. Deletion of the C-terminal NITY759 sequence or disruption of the NPLY747 motif by a Y747A substitution impaired extracellular conformational changes on αvβ3 following RGDS, echistatin or Mn2+ binding, whereas the substitutions Y747F, Y759A or Y759F allowed normal LIBS exposure. Furthermore, metabolic energy depletion totally prevented Mn2+-dependent LIBS exposure, but had only a minor effect on RGDS-induced conformational changes. Our results demonstrate that the structural integrity of the NPLY747 motif in the β3 cytoplasmic domain, rather than potential phosphorylation of Tyr747 or Tyr759, is a prerequisite for conformational changes within the αvβ3 ectodo-main, and suggest that two different mechanisms are responsible for RGDS- and Mn2+-dependent conformational changes.
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45

Ferreira, O. C., A. Garcia-Pardo, and C. Bianco. "Specific binding of the human monocytic cell line U937 to the alternatively spliced connecting segment (IIICS) of fibronectin." Journal of Experimental Medicine 171, no. 1 (1990): 351–56. http://dx.doi.org/10.1084/jem.171.1.351.

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U937 cells attach to the RGDS-containing 80-kD fragment of fibronectin (Fn). The present report examined whether these cells recognize other domains of Fn. U937 cells attach to a 38-kD fragment derived from the A chain of Fn, which includes the Hep II domain and most of the alternatively spliced IIICS region. U937 did not bind to a 58-kD fragment derived from the B chain (which lacks IIICS) and has the Hep II site. They also did not bind to a 31-kD COOH-terminal fibrin-binding fragment or to a 29-kD fragment containing the Hep I domain. Cell adhesion to the 38-kD fragment was not inhibited by the 80-kD fragment, by GRGDSPC synthetic peptides, or by a mAb directed to the RGDS-containing domain of Fn. Attachment was completely inhibited by the 38-kD fragment and by the synthetic peptide CS-1, comprising the first 25 amino acid residues of IIICS. These results indicate that U937 cells interact with two sites of Fn, the RGDS-containing region, and the IIICS region.
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46

Sorisky, A., W. G. King, and S. E. Rittenhouse. "Accumulation of PtdIns(3,4)P2 and PtdIns(3,4,5)P3 in thrombin-stimulated platelets. Different sensitivities to Ca2+ or functional integrin." Biochemical Journal 286, no. 2 (1992): 581–84. http://dx.doi.org/10.1042/bj2860581.

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Differences in regulation of the accumulation of PtdIns(3,4)P2 versus that of PtdIns(3,4,5)P3 were noted in thrombin-stimulated human platelets. The rapid (within 20 s) response of PtdIns(3,4,5)P3 contrasted with a distinct lag in the accumulation of PtdIns(3,4)P2 that was followed by a pronounced increase by 90 s. The presence of 2.5 mM-CaCl2 further elevated PtdIns(3,4)P2 by 50-120%, but only at a late stage (after 90 s). Tetrapeptide RGDS (Arg-Gly-Asp-Ser), which blocks the interaction of ligands such as fibrinogen with platelet integrin alpha IIb beta 3 (GPIIb-IIIa), inhibited only the late-phase PtdIns(3,4)P2 accumulation that was associated with added Ca2+. Although stimulated tyrosine phosphorylation of platelet protein (total cell lysate) was altered by Ca2+ or RGDS, we could not identify any such proteins that were affected comparably to PtdIns(3,4)P2. In contrast to the PtdIns(3,4)P2 response, the accumulation of PtdIns(3,4,5)P3 was unaffected by Ca2+ or RGDS at any time.
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47

Singer, I. I., D. W. Kawka, S. Scott, R. A. Mumford, and M. W. Lark. "The fibronectin cell attachment sequence Arg-Gly-Asp-Ser promotes focal contact formation during early fibroblast attachment and spreading." Journal of Cell Biology 104, no. 3 (1987): 573–84. http://dx.doi.org/10.1083/jcb.104.3.573.

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Cultured fibroblasts form focal contacts (FCs) associated with actin microfilament bundles (MFBs) during attachment and spreading on serum- or fibronectin (FN)-coated substrates. To determine if the minimum cellular adhesion receptor recognition signal Arg-Gly-Asp-Ser (RGDS) is sufficient to promote FC and MFB formation, rat (NRK), hamster (Nil 8), and mouse (Balb/c 3T3) fibroblasts in serum-free media were plated on substrates derivatized with small synthetic peptides containing RGDS. These cultures were studied with interference reflection microscopy to detect FCs, Normarski optics to identify MFBs, and immunofluorescence microscopy to observe endogenous FN fiber formation. By 1 h, 72-78% of the NRK and Nil 8 cells plated on RGDS-containing peptide had focal contacts without accompanying FN fibers, while these fibroblasts lacked FCs on control peptide. This early FC formation was followed by the appearance of coincident MFBs and colinear FN fibers forming fibronexuses at 4 h. NRK and Nil 8 cultures on substrates coated with native FN or 75,000-D FN-cell binding fragment showed similar kinetics of FC and MFB formation. In contrast, the Balb/c 3T3 mouse fibroblasts plated on Gly-Arg-Gly-Asp-Ser peptide-derivatized substrates, or on coverslips coated with 75,000-D FN cell-binding fragment, were defective in FC formation. These results demonstrate that the apparent binding of substrate-linked RGDS sequences to cell surface adhesion receptors is sufficient to promote early focal contact formation followed by the appearance of fibronexuses in some, but not all, fibroblast lines.
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48

Feric, Nicole T., Calvin C. H. Cheng, M. Cynthia Goh, Vyacheslav Dudnyk, Val Di Tizio, and Milica Radisic. "Angiopoietin-1 peptide QHREDGS promotes osteoblast differentiation, bone matrix deposition and mineralization on biomedical materials." Biomater. Sci. 2, no. 10 (2014): 1384–98. http://dx.doi.org/10.1039/c4bm00073k.

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49

Sedlačík, T., O. K. Acar, H. Studenovská та ін. "Chondrogenic potential of macroporous biodegradable cryogels based on synthetic poly(α-amino acids)". Soft Matter 14, № 2 (2018): 228–38. http://dx.doi.org/10.1039/c7sm02074k.

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50

Soultan, Al Halifa, Thomas Verheyen, Mario Smet, Wim M. De Borggraeve, and Jennifer Patterson. "Synthesis and peptide functionalization of hyperbranched poly(arylene oxindole) towards versatile biomaterials." Polymer Chemistry 9, no. 20 (2018): 2775–84. http://dx.doi.org/10.1039/c8py00139a.

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