Lactadherin binding and phosphatidylserine expression on cell surface-comparison with annexin A5
Lactadherin binding and phosphatidylserine expression on cell surface-comparison with annexin A5
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DOI：
10.1016/j.lab.2006.03.006
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发表时间：
2006-07-01
影响因子：
7.8
通讯作者：
Thiagarajan, Perlimal
中科院分区：
文献类型：
--
作者：
Dasgupta, Swapan K.;Guchhait, Prasenjit;Thiagarajan, Perlimal
背景资料：在血小板活化、红细胞衰老和细胞凋亡过程中，阴离子磷脂从质膜的内叶到外叶的跨双层运动发生。阴离子磷脂结合蛋白，膜联蛋白AS，已被用来检测存在的磷脂酰丝氨酸的细胞膜的外部小叶。巨噬细胞分泌的一种糖蛋白--乳凝集素，与凋亡细胞上的磷脂酰丝氨酸结合，促进其被巨噬细胞清除。研究方法：作者分离并标记lactadherin和annexin A5与FITC，并比较其通过流式细胞术检测磷脂酰丝氨酸表达的能力。结果如下：当用凝血酶（0.1单位/mL）或Ca 2+离子载体A23187（1 μ M）激活血小板时，FITC-乳凝集素诱导的直方图偏移和平均荧光强度高于FITC-膜联蛋白A5。同样，乳凝集素在检测诱导表达磷脂酰丝氨酸的红细胞中的磷脂酰丝氨酸时更敏感。此外，在HL 60细胞凋亡，lactadherin检测磷脂酰丝氨酸表达早于膜联蛋白A5。在弥漫性血管内凝血患者中，乳凝集素检测到大多数患者表达磷脂酰丝氨酸的血小板，而在类似条件下，FITC-膜联蛋白A5不能。结论：作者的研究表明，在检测表达磷脂酰丝氨酸的活化血小板、红细胞和凋亡细胞方面，FITC-乳凝集素是比膜联蛋白AS更好的探针。
Background: Transbilayer movement of anionic phospholipids from the inner to the outer leaflet of the plasma membrane occurs during platelet activation, red cell senescence, and apoptosis. The anionic phospholipid-binding protein, annexin AS, has been used to detect the presence of phosphatidylserine on the outer leaflet of the cell membrane. Lactadherin, a glycoprotein secreted by macrophages, binds to phosphatidylserine on apoptotic cells and promote their clearance by macrophages. Methods: The authors isolated and labeled lactadherin and annexin A5 with FITC and compared their ability to detect phosphatidylserine expression by flow cytometry. Results: FITC-lactadherin induced greater shift in the histogram and a higher mean fluorescence intensity than FITC-annexin A5 when platelets were activated with thrombin (0.1 unit/mL) or Ca2+ ionophore A23187 (1 mu M). Similarly, lactadherin was more sensitive in detecting phosphatidylserine in red cells induced to express phosphatidylserine. Also, in HL 60 cells undergoing apoptosis, lactadherin detected phosphatidylserine expression earlier than annexin A5. In patients with disseminated intravascular coagulation, lactadherin detected phosphatildyl-serine-expressing platelets in most patients, whereas under similar conditions, FITC-annexin A5 could not. Conclusions: The authors' studies show that FITC-lactadherin is a better probe than annexin AS in detecting phosphatidylserine-expressing activated platelets, red cells, and apoptotic cells.