Dog platelets accumulate intracellular fibrinogen as they age.
Dog platelets accumulate intracellular fibrinogen as they age.
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随着年龄的增长，狗的血小板会积聚细胞内纤维蛋白原。
DOI：
10.1002/jcp.1041610104
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发表时间：
1994
影响因子：
5.6
通讯作者：
Dale,GL
中科院分区：
文献类型：
--
作者：
Heilmann,E;Hynes,LA;Friese,P;George,IN;Burstein,SA;Dale,GL
循环血小板的α颗粒是分别通过合成和摄取获得内源性和外源性组分的动态结构。外源性成分的摄取是受体介导的内吞作用或液相胞饮作用的结果。尽管对α颗粒的功能和含量进行了许多详细的研究，但对血小板年龄对这些细胞器的影响知之甚少。在这份报告中，我们描述了使用血小板生物素化来鉴定和分离老化血小板，以分析α颗粒含量。当老年血小板透化，并利用荧光标记抗体的流式细胞术检查，两个外源获得的蛋白质，纤维蛋白原和免疫球蛋白G，被发现显着增加与血小板年龄。发现细胞内纤维蛋白原水平相对于对照升高，在生物素化后第4天和第5天分别为114 ± 2%和119 ± 5%;犬血小板的寿命为6.0天。细胞内免疫球蛋白G含量增加相似。两种内源性合成的蛋白质，血小板反应蛋白和P-选择素，在老化血小板中没有升高。通过荧光激活细胞分选分离老化的生物素化血小板，并采用ELISA测定法定量纤维蛋白原水平，确认流式细胞术数据。对于平均4.6日龄的血小板，纤维蛋白原水平升高至整个血小板群体水平的128 ± 23%。这些数据表明，外源性α颗粒蛋白确实会发生年龄依赖性变化，并且这些蛋白质的吸收机制在整个血小板寿命期间都是活跃的。© 1994 Wiley利斯公司
The alpha granules of circulating platelets are dynamic structures that acquire endogenous and exogenous components by synthesis and uptake, respectively. The uptake of exogenous components is a result of either receptor‐mediated endocytosis or fluid‐phase pinocytosis. Despite many detailed studies on the function and content of α‐granules, little is known of the impact of platelet age on these organelles. In this report, we describe the use of platelet biotinylation to identify and isolate aged platelets for the analysis of α‐granule contents. When aged platelets were permeabilized and examined by flow cytometry utilizing fluorescently labeled antibodies, two exogenously acquired proteins, fibrinogen and immunoglobulin G, were found to increase significantly with platelet age. The levels of intracellular fibrinogen were found to be elevated relative to control, 114 ± 2% and 119 ± 5% on days 4 and 5 postbiotinylation, respectively; the life span of dog platelets is 6.0 days. Intracellular immunoglobulin G content increased similarly. Levels of two endogenously synthesized proteins, thrombosponding and P‐selectin, were not elevated in aged platelets. Confirmation of the flow cytometric data was obtained by isolating aged, biotinylated platelets by fluorescence‐activated cell sorting and quantitating the fibrinogen levels with an ELISA assay. For platelets averaging 4.6 days of age, the fibrinogen level was elevated to 128 ± 23% of the level for the entire platelet population. These data demonstrate that age‐dependent changes in exogenously acquired α‐granule proteins do occur and that the uptake mechanism for these proteins is active through out the platelet life span. © 1994 Wiley‐Liss, Inc.