Novel synthetic collagen fibers, poly(PHG), stimulate platelet aggregation through glycoprotein VI.

Novel synthetic collagen fibers, poly(PHG) made by polycondensation of Pro-Hyp-Gly, spontaneously assume polymeric structure with molecular weights greater than 10(5). Its application for biomaterials has been explored, but that for a platelet agonist has not been investigated. Poly(PHG)-induced platelet aggregation independently of thromboxane A(2) and integrin alpha2beta1. Poly(PHG)-induced tyrosine phosphorylation of glycoprotein VI (GPVI)-related molecules and failed to activate GPVI/FcRgamma-deficient platelets. Binding of GPVI to poly(PHG) was confirmed by a surface plasmon resonance spectroscopy, suggesting that poly(PHG) activates platelets through GPVI. Poly(PHG) is an useful research tool to investigate GPVI-mediated signals and a substitute for collagen in platelet functional assays.