Multivesicular bodies are an intermediate stage in the formation of platelet α-granules
Multivesicular bodies are an intermediate stage in the formation of platelet α-granules
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DOI：
10.1182/blood.v91.7.2313.2313_2313_2325
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发表时间：
1998-04-01
期刊：
影响因子：
20.3
通讯作者：
Sixma, JJ
中科院分区：
文献类型：
--
作者：
Heijnen, HFG;Debili, N;Sixma, JJ
我们用超薄冰冻切片和免疫金细胞化学方法研究了α-粒细胞在巨核细胞和血小板的内吞和生物合成途径中的位置。在形态上，我们区分了三种类型的颗粒：所谓的多泡小体I型(MVB I)，其内部仅有小泡和电子致密基质(MVB II)颗粒，以及主要内容密集的α颗粒，其外围通常是内膜小泡。在培养的巨核细胞和巨核母细胞系CHRF-288中，微血管密度较高，但在骨髓巨核细胞和血小板中数量较少，而α颗粒在成熟的骨髓巨核细胞和血小板中最为显著。牛血清白蛋白-金颗粒和纤维蛋白原的内化动力学依次位于MVB亚型和α-颗粒的内吞途径中。MVBS含有分泌蛋白von Willebrand因子(VWF)和β-血栓球蛋白(β=TG)、血小板特异性膜蛋白P-选择素和溶酶体膜蛋白CD63。在MVB中，内吞的纤维蛋白原和内源性的β-TG仅局限于基质，而vWF主要与内囊泡有关。CD63还与α颗粒中的内膜小泡相关。这些观察结果，以及从含有囊泡的颗粒到以致密物质为主的颗粒的逐渐形态转变，表明MVB代表着α颗粒成熟的一个发育阶段。(C)1998年由美国血液病学会主办。
We have used ultrathin cryosectioning and immunogold cytochemistry to study the position of alpha-grannies in the endocytic and biosynthetic pathways in megakaryocytes and platelets. Morphologically, we distinguished three types of granules; so-called multivesicular bodies type I (MVB I) with internal vesicles only granules with internal vesicles and an electron dense matrix (MVB II), and the alpha-granules with mainly a dense content and often internal membrane vesicles at their periphery. The MVBs were prominent in cultured megakaryocytes and the megakaryoblastic cell line CHRF-288, but were less numerous in bone marrow megakaryocytes and platelets, whereas alpha-granules were most prominent in mature bone marrow megakaryocytes and in platelets. The internalization kinetics of bovine serum albumin-gold particles and of fibrinogen positioned the MVB subtypes and alpha-granules sequentially in the endocytic pathway. MVBs contained the secretory proteins von Willebrand factor (VWF) and beta-thromboglobulin (beta=TG), the platelet-specific membrane protein P-selectin, and the lysosomal membrane protein CD63. Within the MVBs, endocytosed fibrinogen and endogenous beta-TG were restricted to the matrix, while vWF was predominantly associated with internal vesicles. CD63 was also observed in association with internal membrane vesicles in the alpha-granules. These observations, and the gradual morphologic transition from granules containing vesicles to granules containing predominantly dense material, suggest that MVBs represent a developmental stage in alpha-granule maturation. (C) 1998 by The American Society of Hematology.