IndraLab

"For the present question of the binding of α5β1 with PHSRN and RGD, inhibition studies here and in a previous report have shown that both PHSRN and RGD are capable of competitively binding to this integrin to block cell adhesion to substrates presenting either peptide.( xref ) Another study similarly showed that both RGD and a PHSRN-containing peptide could inhibit the interaction between the αIIbβ3 integrin and FN.( xref ) These reports, taken together with the adhesion data presented in this current study, support a model where PHSRN and RGD competitively bind to the same site in the integrin receptor to mediate cell adhesion."

"The process of platelet interaction with the vessel wall and subendothelial matrix is accomplished through the involvement of many platelet receptors and their corresponding ligands ( xref ).[ xref ] Major platelet surface receptors include the GPIb-IX-V complex, GPVI, integrins αIIbβ3 (also known as GPIIbIIIa), α2β1, α5β1, α6β1, thrombin receptors PAR1 and PAR4 (protease activated receptors), ADP receptors (P2Y1, P2Y12 and P2X1) and thromboxane A2 receptors (TP).[ xref ] Platelet adhesion: Platelet-vessel wall interaction, the tethering and adhesion of platelets to the injured site, is primarily mediated by platelet surface GPIbα receptor in GPIb-IX-V complex which binds to the A1 domain of von Willebrand factor (VWF) immobilized on collagen upon vascular injury, particularly at high shear stress.[ xref ] Subsequent stable platelet adhesion is further mediated by other integrin ligands with their corresponding ligands such as integrin αIIbβ3 bound to fibronectin and fibrinogen/fibrin, α5β1 to fibronectin or collagen, and α2β1 to collagen.[ xref ] Platelet activation : Following initial tethering and adhesion of circulating resting platelets at the site of vascular injury, platelets rapidly undergo a well-defined signaling cascade (Ca 2+ influx, degranulation, phosphatidylserine exposure, etc.) that leads to platelet shape change facilitating further platelet activation and platelet granule release.[ xref ] Platelet α-granule (P-selectin[ xref ], VWF[ xref ], fibrinogen (Fg)[ xref ], fibronectin[ xref ], vitronectin[ xref ], multimerin[ xref ], platelet factor 4[ xref ], and many other proteins) and dense granule (adenosine di-phosphate (ADP), polyphosphates and other) contents are secreted and, in turn, amplify the activation process of integrin αIIbβ3 inside-out signaling, leading to further platelet aggregation.[ xref ] GPIba-VWF interaction is also shown to play an important role in platelet adhesion at low shear conditions.[ xref ] Platelet aggregation: Activation of platelets is a critical step for aggregation."