title: Factor XIII mediates adhesion of platelets to endothelial cells through alpha(v)beta(3) and glycoprotein IIb/IIIa integrins.
abstract: Coagulation factor XIII (FXIII) is a transglutaminase that catalyzes crosslink formation in fibrin clots. Endothelial cells (EC) were demonstrated to bind FXIII via their alpha(v)beta3 integrin receptor. FXIII was also shown to bind platelet glycoprotein IIb/IIIa receptor. In the present study, we analyzed if FXIII can mediate platelet-EC interaction. Both FXIII and activated FXIII (FXIIIa) bound to EC monolayers; this binding was enhanced by the addition of Mn2+ and was inhibited by the monoclonal antibody L609 against alpha(v)beta3 integrin. Normal washed platelets also bound surface-immobilized or soluble FXIII and FXIIIa, and the binding was GPIIb/IIIa dependent. The effect of FXIII concentrate (Fibrogammin-P) treatment on the interaction of ECs with platelets from six FXIII-deficient patients was studied. Patients' platelets were radiolabeled with 3H-Adenine, washed, resuspended in autologous plasma and allowed to adhere to immortalized EC line EAhy926. Adhesion of platelets from FXIII-deficient patients to ECs increased 1.7+/-0.4-fold (P=.01) following intravenous infusion of FXIII concentrate. Similarly, addition of 1 U/ml of FXIII concentrate to the patients' PRP in vitro increased the adhesion 1.8+/-0.5-fold (P=.008). Preincubation of the EC monolayers with increasing concentrations of either FXIII or FXIIIa augmented the adhesion of normal washed platelets to ECs in a dose-dependent manner. At 10 U/ml of EC-bound FXIII or FXIIIa, platelet adhesion enhanced 1.7+/-0.25-fold (P=.03) and 2.5+/-0.5-fold (P=.02), respectively. The increase in platelet adhesion was completely abolished by pretreatment of ECs with the anti-alpha(v)beta3 antibody L609 or by preincubation of the platelets with the GPIIb/IIIa inhibitor Abciximab. Taken together, our data indicate that FXIII mediates the interaction of platelets with ECs by bridging between endothelial alpha(v)beta3 and platelet GPIIb/IIIa integrins. This interaction may be relevant for tissue remodeling and wound repair after vascular injury in FXIII-deficient patients.
authors.affiliation: Institute of Thrombosis and Hemostasis, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Hashomer, Tel Aviv, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Dardik
authors.forename: B
authors.initials: B
authors.lastname: Shenkman
authors.forename: I
authors.initials: I
authors.lastname: Tamarin
authors.forename: R
authors.initials: R
authors.lastname: Eskaraev
authors.forename: J
authors.initials: J
authors.lastname: Harsfalvi
authors.forename: D
authors.initials: D
authors.lastname: Varon
authors.forename: A
authors.initials: A
authors.lastname: Inbal
mesh_terms: D002460:Cell Line; D004730:Endothelium, Vascular / Q000502:physiology; D005176:Factor XIII / Q000494:pharmacology / Q000502:physiology*; D005177:Factor XIII Deficiency / Q000097:blood*; D026122:Factor XIIIa / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D039302:Integrin alphaVbeta3 / Q000097:blood*; D010973:Platelet Adhesiveness / Q000187:drug effects / Q000502:physiology*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000502:physiology*; D012995:Solubility
chemical_list: D039302:Integrin alphaVbeta3; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D005176:Factor XIII; D026122:Factor XIIIa