Dardik R, Shenkman B, Tamarin I, Eskaraev R, Harsfalvi J, Varon D, Inbal A
Institute of Thrombosis and Hemostasis, Sheba Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Hashomer, Tel Aviv, Israel.
Thromb Res. 2002 Feb 15;105(4):317-23. doi: 10.1016/s0049-3848(02)00014-2.
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.
凝血因子 XIII（FXIII）是一种转谷氨酰胺酶，可催化纤维蛋白凝块中的交联形成。内皮细胞（EC）已被证明可通过其α(v)β3整合素受体结合FXIII。FXIII也被证明可结合血小板糖蛋白IIb/IIIa受体。在本研究中，我们分析了FXIII是否能介导血小板与内皮细胞的相互作用。FXIII和活化的FXIII（FXIIIa）均与内皮细胞单层结合；添加Mn2+可增强这种结合，而针对α(v)β3整合素的单克隆抗体L609可抑制这种结合。正常洗涤血小板也能结合表面固定化或可溶性的FXIII和FXIIIa，且这种结合依赖于GPIIb/IIIa。研究了FXIII浓缩物（Fibrogammin-P）治疗对6名FXIII缺乏症患者的内皮细胞与血小板相互作用的影响。用3H-腺嘌呤对患者的血小板进行放射性标记，洗涤后，重悬于自体血浆中，并使其黏附于永生化内皮细胞系EAhy926。静脉输注FXIII浓缩物后，FXIII缺乏症患者的血小板与内皮细胞的黏附增加了1.7±0.4倍（P = 0.01）。同样，在体外向患者的富血小板血浆中添加1 U/ml的FXIII浓缩物可使黏附增加1.8±0.5倍（P = 0.008）。用浓度递增的FXIII或FXIIIa对内皮细胞单层进行预孵育，可使正常洗涤血小板与内皮细胞的黏附呈剂量依赖性增加。当内皮细胞结合的FXIII或FXIIIa浓度为10 U/ml时，血小板黏附分别增强了1.7±0.25倍（P = 0.03）和2.5±0.5倍（P = 0.02）。用抗α(v)β3抗体L609预处理内皮细胞或用GPIIb/IIIa抑制剂阿昔单抗对血小板进行预孵育，可完全消除血小板黏附的增加。综上所述，我们的数据表明，FXIII通过在内皮细胞的α(v)β3和血小板的GPIIb/IIIa整合素之间形成桥梁，介导血小板与内皮细胞的相互作用。这种相互作用可能与FXIII缺乏症患者血管损伤后的组织重塑和伤口修复有关。
