Platelet-derived ERp57 mediates platelet incorporation into a growing thrombus by regulation of the βIIbβ3 integrin
Platelet-derived ERp57 mediates platelet incorporation into a growing thrombus by regulation of the βIIbβ3 integrin
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DOI：
10.1182/blood-2013-06-506691
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发表时间：
2013-11-21
期刊：
影响因子：
20.3
通讯作者：
Essex, David W.
中科院分区：
文献类型：
--
作者：
Wang, Lu;Wu, Yi;Essex, David W.
称为ERp 57的血小板蛋白二硫键异构酶介导血小板聚集，但其在血栓形成中的作用尚不清楚。为了确定血小板衍生的ERp 57在止血和血栓形成中的特定作用，我们产生了巨核细胞/血小板特异性敲除。尽管血小板计数和血小板糖蛋白表达正常，但ERp 57缺陷型血小板小鼠的尾部出血时间和血栓闭塞时间延长，FeCl 3诱导的颈动脉损伤。使用肠系膜动脉血栓形成模型，我们发现减少ERp 57缺陷型血小板纳入一个不断增长的血栓。缺乏ERp 57的血小板具有缺陷的α IIb β 3整合素活化和血小板聚集。通过加入外源性ERp 57纠正了聚集缺陷，表明表面ERp 57参与了血小板聚集。使用ERp 57的突变体，我们证明了第二个活性位点靶向血小板表面底物，以增强血小板聚集。Alexa 488标记的ERp 57与凝血酶活化和Mn 2+处理的缺乏β 3的血小板的结合显著降低，表明ERp 57与α IIb β 3直接相互作用。人血小板中ERp 57蛋白的表面表达和活性随着血小板活化而增加，蛋白表达发生在生理相关的时间范围内。总之，血小板衍生的ERp 57在该受体的活化过程中直接与α IIb β 3相互作用，并且是血小板掺入生长的血栓所必需的。
The platelet protein disulfide isomerase called ERp57 mediates platelet aggregation, but its role in thrombus formation is unknown. To determine the specific role of platelet-derived ERp57 in hemostasis and thrombosis, we generated a megakaryocyte/platelet-specific knockout. Despite normal platelet counts and platelet glycoprotein expression, mice with ERp57-deficient platelets had prolonged tail-bleeding times and thrombus occlusion times with FeCl3-induced carotid artery injury. Using a mesenteric artery thrombosis model, we found decreased incorporation of ERp57-deficient platelets into a growing thrombus. Platelets lacking ERp57 have defective activation of the alpha IIb beta 3 integrin and platelet aggregation. The defect in aggregation was corrected by the addition of exogenous ERp57, implicating surface ERp57 in platelet aggregation. Using mutants of ERp57, we demonstrate the second active site targets a platelet surface substrate to potentiate platelet aggregation. Binding of Alexa 488-labeled ERp57 to thrombin-activated and Mn2+-treated platelets lacking beta 3 was decreased substantially, suggesting a direct interaction of ERp57 with alpha IIb beta 3. Surface expression of ERp57 protein and activity in human platelets increased with platelet activation, with protein expression occurring in a physiologically relevant time frame. In conclusion, platelet-derived ERp57 directly interacts with alpha IIb beta 3 during activation of this receptor and is required for incorporation of platelets into a growing thrombus.