Abnormal megakaryocyte development and platelet function in Nbeal2-/- mice
Abnormal megakaryocyte development and platelet function in Nbeal2-/- mice
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DOI：
10.1182/blood-2013-04-499491
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发表时间：
2013-11-07
期刊：
影响因子：
20.3
通讯作者：
Gross, Peter L.
中科院分区：
文献类型：
--
作者：
Kahr, Walter H. A.;Lo, Richard W.;Gross, Peter L.
灰色血小板综合征（GPS）是一种遗传性出血性疾病，与巨血小板减少症和α-颗粒缺陷型血小板有关。GPS与NEABL 2（神经海滩蛋白样2）的功能缺失突变有关，我们在此描述了一种鼠GPS模型，Nbeal 2（-/-）小鼠。如在GPS中，Nbeal 2（-/-）小鼠表现出脾肿大、巨血小板减少症和血小板α颗粒及其货物（包括血管性血友病因子（VWF）、血小板反应蛋白-1和血小板因子4）的缺乏。血小板α-颗粒膜蛋白P-选择素以野生型水平的48%表达，并在血小板活化后外化。Nbeal 2（-/-）血小板中P-选择素的存在以及VPS 33 B和VPS 16 B的正常水平表明Nbeal 2在α颗粒生物发生的后期阶段独立于VPS 33 B/VPS 16 B发挥作用。通过流式细胞术、血小板聚集测定、出血测定和激光诱导动脉血栓形成的活体成像显示Nbeal 2（-/-）血小板功能受损。显微镜分析检测到Nbeal 2（-/-）骨髓巨核细胞的显著异常，其在培养时显示成熟延迟、存活率降低、倍性降低和发育异常，包括VWF的异常细胞外分布。我们的研究结果证实了α-颗粒分泌在血小板功能中起重要作用，并且它们还表明Nbeal 2（-/-）小鼠中异常的α-颗粒形成对巨核细胞存活、发育和血小板产生具有有害影响。
Gray platelet syndrome (GPS) is an inherited bleeding disorder associated with macrothrombocytopenia and alpha-granule-deficient platelets. GPS has been linked to loss of function mutations in NEABL2 (neurobeachin-like 2), and we describe here a murine GPS model, the Nbeal2(-/-) mouse. As in GPS, Nbeal2(-/-) mice exhibit splenomegaly, macrothrombocytopenia, and a deficiency of platelet alpha-granules and their cargo, including von Willebrand factor (VWF), thrombospondin-1, and platelet factor 4. The platelet alpha-granule membrane protein P-selectin is expressed at 48% of wild-type levels and externalized upon platelet activation. The presence of P-selectin and normal levels of VPS33B and VPS16B in Nbeal2(-/-) platelets suggests that NBEAL2 acts independently of VPS33B/VPS16B at a later stage of alpha-granule biogenesis. Impaired Nbeal2(-/-) platelet function was shown by flow cytometry, platelet aggregometry, bleeding assays, and intravital imaging of laser-induced arterial thrombus formation. Microscopic analysis detected marked abnormalities in Nbeal2(-/-) bone marrow megakaryocytes, which when cultured showed delayed maturation, decreased survival, decreased ploidy, and developmental abnormalities, including abnormal extracellular distribution of VWF. Our results confirm that alpha-granule secretion plays a significant role in platelet function, and they also indicate that abnormal alpha-granule formation in Nbeal2(-/-) mice has deleterious effects on megakaryocyte survival, development, and platelet production.