Platelet/polymorphonuclear leukocyte interaction in dynamic conditions: evidence of adhesion cascade and cross talk between P-selectin and the beta 2 integrin CD11b/CD18.
Platelet/polymorphonuclear leukocyte interaction in dynamic conditions: evidence of adhesion cascade and cross talk between P-selectin and the beta 2 integrin CD11b/CD18.
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DOI：
10.1182/blood.v88.11.4183.4183
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发表时间：
1996-12
期刊：
影响因子：
20.3
通讯作者：
V. Evangelista;S. Manarini;S. Rotondo;N. Martelli;R. Polischuk;JL McGregor;G. Gaetano;C. Cerletti
中科院分区：
文献类型：
--
作者：
V. Evangelista;S. Manarini;S. Rotondo;N. Martelli;R. Polischuk;JL McGregor;G. Gaetano;C. Cerletti
血小板与中性粒细胞(PMN)之间的黏附是血栓形成和炎症的关键事件。采用双色荧光激活细胞分选仪(FACS)检测混合细胞群体动态孵育时凝血酶激活的血小板与静息或激活的PMN的黏附程度和黏附动力学。活化的血小板会非常迅速地与中性粒细胞结合。混合细胞结合物在1分钟达到最大值，10分钟内可逆。血小板/PMN的粘附性既需要钙离子又需要镁离子，加入Mn2+可明显增强血小板/PMN的粘附性。后者使混合细胞结合物稳定长达10分钟。血小板的黏附需要PMN的代谢活性，并可被酪氨酸激酶抑制剂消除。此外，血小板与中性粒细胞的黏附导致一种称为β2整合素“激活报告基因”的单抗(单抗24)的结合。当PMN被外源性刺激激活时，血小板的粘附性显著增加：fMLP引起快速而短暂的作用，而PMA引起缓慢但稳定的混合结合物形成增加。两种抗CD18抗体KIM127和KIM185处理PMN后，混合细胞结合物的增加直接证明了激活的PMNβ2整合素能够结合血小板上的对抗性受体的假说。另外两种抗CD18抗体以及一种抗CD11b抑制抗体可以消除血小板/中性粒细胞的黏附。PMNβ2整合素激活并不是活化的血小板/PMN黏附发生的唯一机制：事实上，这一现象也可以被两种抗P-选择素抗体抑制。静息状态下的血小板与静息的PMN无粘附性，但与fMLP或PMA激活的PMN有明显的粘附性。抗CD18抗体可消除静息状态下的血小板/fMLP激活的PMN黏附，而抗P-选择素抗体则不能。总之，活化的血小板/中性粒细胞相互作用可被模拟为一个黏附级联反应，涉及P-选择素依赖的识别步骤和功能信号。后者通过酪氨酸激酶的激活而进行，使β2整合素依赖于与血小板表面结构性表达的尚未鉴定的对抗性受体的黏附。
Adhesion between platelets and polymorphonuclear leukocytes (PMN) is a key event in thrombosis and inflammation. Double color fluorescence-activated cell sorter (FACS) analysis was used to determine the extent and kinetics of adhesion of thrombin-activated platelets to resting or activated PMN when mixed cell populations were incubated in dynamic conditions. Activated platelets bound very rapidly to PMN. Mixed cell conjugates reached a maximum at 1 minute and were reversible within 10 minutes. Platelet/PMN adhesion required both Ca2+ and Mg2+ and was markedly increased by the presence of Mn2+. The latter made mixed cell conjugates stable up to 10 minutes. Adhesion of platelets required metabolic activity of PMN and was abolished by tyrosine kinase inhibitors. Furthermore, adhesion of platelets to PMN resulted in binding of a monoclonal antibody (MoAb 24) known as beta 2 integrins "activation reporter." When PMN were activated by exogenous stimuli, the adhesion of platelets was markedly increased: fMLP induced a rapid and transient effect, while PMA resulted in a slower, but stable, increase in mixed conjugates formation. The hypothesis that activated PMN beta 2 integrins are able to bind a counter-receptor on platelets was directly demonstrated by the increase of mixed cell conjugates following PMN treatment with KIM127 and KIM185, two anti-CD18 antibodies able to induce the active conformation of beta 2 integrins. Consistently, two other anti-CD18, as well as an anti-CD11b inhibitory antibody abolished platelet/PMN adhesion. PMN beta 2 integrin activation was not the only mechanism for activated platelet/PMN adhesion to occur: indeed, this phenomenon could also be inhibited by two anti-P-selectin antibodies. Resting platelets did not adhere to resting PMN, but markedly adhered to fMLP- or PMA-activated PMN. Resting platelet/fMLP-activated PMN adhesion was abolished by anti-CD18 antibodies, but not by anti-P-selectin antibodies. In conclusion, activated platelet/PMN interaction can be modeled as an adhesion cascade involving a P-selectin-dependent recognition step and a functional signal. The latter proceeds through tyrosine kinase activation and enables a beta 2 integrin-dependent adhesion to a not yet identified counter-receptor constitutively expressed on platelet surface.