Spangenberg P, Till U, Gschmeissner S, Crawford N
Institute of Pathological Biochemistry, Medical Academy of Erfurt, G.D.R.
Br J Haematol. 1987 Dec;67(4):443-50. doi: 10.1111/j.1365-2141.1987.tb06167.x.
Exposure of blood platelets to diamide (azodicarboxylic acid-bis-dimethylamide) results in oxidation of sulphydryl groups present in the cytoskeleton and other proteins. This results in dramatic changes in functional behaviour of the cells. The distribution and level of organization of the major cytoskeletal protein actin has been studied analytically by the DNase-I inhibition assay and morphologically by electron microscopy (EM) of Triton X-100 treated platelets adherent to EM grids. Exposure to diamide results in a redistribution of actin within the cell reflected in an increase in cytoskeletal F-actin and a concomitant decrease in cytosolic actin. The magnitude of these changes depends upon the concentration of diamide and the time of exposure. Diamide also alters platelet aggregatory functions in response to certain stimuli. Treatment of normal human platelets with 0.1 mM diamide proceeds via disaggregation (5 min exposure to diamide), inhibition of aggregation (30 min exposure), to finally a normalization of the aggregation response after 60-120 min incubation with diamide. In parallel with the return to full functional response the distribution of F-actin between the cytoskeleton and cytoplasmic compartments returns to the control pattern. Incubation of the platelets with 0.5 mM diamide for 60 or more minutes leads to total inhibition of the aggregatory ability. In these cells the cytoskeleton associated F-actin remains significantly elevated and the structural organization of the cytoskeleton is markedly altered. In contrast to the network of filaments subadjacent to the surface membrane seen in unstimulated platelets, the cytoskeleton now shows electron dense zones in the more central parts of the cytoplasm. This diamide-induced structural reorganization of platelet cytoskeletal elements, associated with the inhibition of functional responses, emphasizes the dynamic nature of the membrane-cytoskeletal axis and its importance in the expression of shape changes and aggregatory phenomena in response to surface stimuli.
使血小板暴露于二酰胺（偶氮二甲酸双二甲酰胺）会导致细胞骨架及其他蛋白质中存在的巯基发生氧化。这会导致细胞功能行为发生显著变化。主要细胞骨架蛋白肌动蛋白的分布和组织水平已通过DNase-I抑制试验进行了分析研究，并通过对附着在电子显微镜（EM）网格上的经Triton X-100处理的血小板进行电子显微镜（EM）观察进行了形态学研究。暴露于二酰胺会导致细胞内肌动蛋白重新分布，表现为细胞骨架F-肌动蛋白增加，同时胞质肌动蛋白减少。这些变化的程度取决于二酰胺的浓度和暴露时间。二酰胺还会改变血小板对某些刺激的聚集功能。用0.1 mM二酰胺处理正常人血小板时，过程为先解聚（暴露于二酰胺5分钟），然后抑制聚集（暴露30分钟），最终在与二酰胺孵育60 - 120分钟后聚集反应恢复正常。随着功能反应完全恢复，细胞骨架和细胞质区室之间的F-肌动蛋白分布也恢复到对照模式。用0.5 mM二酰胺孵育血小板60分钟或更长时间会导致聚集能力完全抑制。在这些细胞中，与细胞骨架相关的F-肌动蛋白仍显著升高，细胞骨架的结构组织也明显改变。与未刺激血小板中可见的紧邻表面膜的细丝网络不同，现在细胞骨架在细胞质更中心的部分显示出电子致密区。这种由二酰胺诱导的血小板细胞骨架元件的结构重组，与功能反应的抑制相关，强调了膜 - 细胞骨架轴的动态性质及其在响应表面刺激时形状变化和聚集现象表达中的重要性。
