Activated platelets form protected zones of adhesion on fibrinogen and fibronectin-coated surfaces.
Activated platelets form protected zones of adhesion on fibrinogen and fibronectin-coated surfaces.
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DOI：
10.1083/jcb.121.4.945
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发表时间：
1993-05
期刊：
影响因子：
--
通讯作者：
Silverstein SC
中科院分区：
文献类型：
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作者：
Loike JD;Silverstein R;Cao L;Solomon L;Weitz J;Haber E;Matsueda GR;Bernatowicz MS;Silverstein SC
当白细胞粘附在配体包被的表面时，它们形成紧密贴壁的区域。由于血浆蛋白被排除在这些接触区之外，我们称它们为粘附保护区。为了确定血小板是否形成类似的粘附保护区，允许用凝血酶或ADP刺激的凝胶过滤的血小板粘附到纤维蛋白原或纤连蛋白包被的表面。用荧光染料缀合的山羊抗人纤维蛋白原或抗人纤连蛋白抗体或用罗丹明缀合的聚乙二醇聚合物对附着有血小板的蛋白质包被的表面进行染色。荧光显微术显示F（ab '）2抗纤维蛋白原（100 kD）没有渗透到刺激的血小板和下面的纤维蛋白原包被的表面之间的接触区，而Fab抗纤维蛋白原（50 kD）和10 kD聚乙二醇容易渗透并染色血小板下面的底物。凝血酶或ADP刺激的血小板也在纤连蛋白包被的表面上形成粘附保护区。F（ab ′）2抗纤连蛋白和10 kD聚乙二醇被排除在这些粘附区之外，表明它们的渗透性比由血小板在纤维蛋白原包被的表面上形成的那些低得多。受刺激的血小板在涂有纤维蛋白原和纤连蛋白的表面上形成的粘附保护区的渗透性与单独在纤连蛋白上形成的粘附区相似。针对α IIb β 3整联蛋白的mAb 7E3阻断凝血酶刺激的血小板与纤维蛋白原或纤连蛋白包被表面之间受保护的粘附区的形成。mAb C13针对血小板上的α 5 β 1整联蛋白。用这种mAb处理的刺激血小板在用纤连蛋白包被的表面上形成粘附保护区。这些保护区对F（ab '）2抗纤连蛋白是不可渗透的，但对10 kD聚乙二醇是可渗透的。这些结果表明，活化的血小板形成受保护的粘附区，并且从这些区排除的分子的大小取决于血小板粘附的基质蛋白的组成。他们还表明，血小板粘附保护区的形成需要α IIb β 3整联蛋白，而这些粘附区的渗透性由α IIb β 3和α 5 β 1整联蛋白调节。
Leukocytes form zones of close apposition when they adhere to ligand- coated surfaces. Because plasma proteins are excluded from these contact zones, we have termed them protected zones of adhesion. To determine whether platelets form similar protected zones of adhesion, gel-filtered platelets stimulated with thrombin or ADP were allowed to adhere to fibrinogen- or fibronectin-coated surfaces. The protein- coated surfaces with platelets attached were stained with either fluorochrome-conjugated goat anti-human fibrinogen or anti-human fibronectin antibodies, or with rhodamine-conjugated polyethylene glycol polymers. Fluorescence microscopy revealed that F(ab')2 anti- fibrinogen (100 kD) did not penetrate into the contact zones between stimulated platelets and the underlying fibrinogen-coated surface, while Fab antifibrinogen (50 kD) and 10 kD polyethylene glycol readily penetrated and stained the substrate beneath the platelets. Thrombin- or ADP-stimulated platelets also formed protected zones of adhesion on fibronectin-coated surfaces. F(ab')2 anti-fibronectin and 10 kD polyethylene glycol were excluded from these adhesion zones, indicating that they are much less permeable than those formed by platelets on fibrinogen-coated surfaces. The permeability properties of protected zones of adhesion formed by stimulated platelets on surfaces coated with both fibrinogen and fibronectin were similar to the zones of adhesion formed on fibronectin alone. mAb 7E3, directed against the alpha IIb beta 3 integrin blocked the formation of protected adhesion zones between thrombin-stimulated platelets and fibrinogen or fibronectin coated surfaces. mAb C13 is directed against the alpha 5 beta 1 integrin on platelets. Stimulated platelets treated with this mAb formed protected zones of adhesion on surfaces coated with fibronectin. These protected zones were impermeable to F(ab')2 antifibronectin but were permeable to 10 kD polyethylene glycol. These results show that activated platelets form protected zones of adhesion and that the size of molecules excluded from these zones depends upon the composition of the matrix proteins to which the platelets adhere. They also show that formation of protected zones of adhesion by platelets requires alpha IIb beta 3 integrins while the permeability properties of these zones of adhesion are regulated by both alpha IIb beta 3 and alpha 5 beta 1 integrins.