Takeuchi K, Satoh M, Kuno H, Yoshida T, Kondo H, Takeuchi M
Osaka Prefectural College of Health Science, Habikino, Japan.
Br J Haematol. 1998 Feb;100(2):436-44. doi: 10.1046/j.1365-2141.1998.00576.x.
The platelet-sized particle formation in the human megakaryoblastic leukaemia cell line MEG-01 and its subline MEG-01s was examined. MEG-01 and MEG-01s cells spontaneously released platelet-sized particles into the culture medium, in which the cells occasionally extended cytoplasmic processes similar to those of megakaryocyte proplatelets. Scanning electron microscopic images showed cytoplasmic processes elongated from blebs on the MEG-01 and MEG-01s cell surface and were constricted between segments of platelet size. Immunofluorescence staining with anti-tubulin antibody showed that the cytoplasmic processes contained microtubules that were organized into a ring, which is a characteristic of circulating platelets. Some platelet-sized particles, probably released by ruptures at the sites of the process constriction, were metabolically active in an MTT assay (about 50%). Some particles also expressed the platelet-specific glycoproteins GPIIb, IIIa and GMP-140. Rarely, in response to thrombin, particles underwent a shape change from spherical to a shape with irregular membrane protrusions and fine filopodia, and aggregating with one another. The particles also had increased GMP-140 (P-selectin) expression with the addition of thrombin. These results show the usefulness of the MEG-01 and MEG-01s cell lines for the study of thrombopoiesis.
对人巨核母细胞白血病细胞系MEG - 01及其亚系MEG - 01s中血小板大小颗粒的形成进行了检测。MEG - 01和MEG - 01s细胞可自发地将血小板大小的颗粒释放到培养基中，细胞偶尔会伸出类似于巨核细胞前血小板的细胞质突起。扫描电子显微镜图像显示，细胞质突起从MEG - 01和MEG - 01s细胞表面的泡状结构延伸出来，并在血小板大小的节段之间收缩。用抗微管蛋白抗体进行免疫荧光染色显示，细胞质突起含有微管，这些微管排列成环，这是循环血小板的一个特征。一些可能在突起收缩部位破裂而释放的血小板大小的颗粒，在MTT试验中具有代谢活性（约50%）。一些颗粒还表达血小板特异性糖蛋白GPIIb、IIIa和GMP - 140。很少情况下，在凝血酶作用下，颗粒会从球形变为具有不规则膜突起和细丝状伪足的形状，并相互聚集。添加凝血酶后，颗粒的GMP - 140（P - 选择素）表达也增加。这些结果表明MEG - 01和MEG - 01s细胞系在血小板生成研究中的有用性。
