Le Cabec V, Calafat J, Borregaard N
Department of Hematology, Finsen Center, The National University Hospital, Rigshospitalet, Copenhagen, Denmark.
Blood. 1997 Mar 15;89(6):2113-21.
The different types of human neutrophil granules (azurophil, specific, and gelatinase granules) are formed sequentially during maturation of neutrophils from the promyelocyte stage to the band cell stage. The promyelocytic HL-60 cells can maturate to segmented granulocytes but are incapable of activating the transcription of any known intragranular protein, normally located in specific or gelatinase granules. To study the sorting of granule proteins during maturation, we transfected HL-60 cells with the specific granule protein NGAL, inserted under control of a cytomegalovirus promoter. We previously showed that NGAL is sorted to azurophil granules and colocalizes with myeloperoxidase in undifferentiated HL-60 cells. We show here that, when such transfected HL-60 cells differentiate into granulocytes, newly synthesized NGAL is not retained in granules but is constitutively secreted. This indicates that highly specific mechanisms must exist that are responsible for diverting transport vesicles into storage granules, and that HL-60 cells not only lack the ability to activate transcription of specific granule proteins, but also lose the ability to form storage granules during maturation.
人类中性粒细胞的不同类型颗粒（嗜天青颗粒、特异性颗粒和明胶酶颗粒）在中性粒细胞从早幼粒细胞阶段到杆状核细胞阶段的成熟过程中依次形成。早幼粒细胞性HL-60细胞可以成熟为分叶核粒细胞，但无法激活任何已知的通常位于特异性颗粒或明胶酶颗粒中的颗粒内蛋白的转录。为了研究成熟过程中颗粒蛋白的分选，我们用在巨细胞病毒启动子控制下插入的特异性颗粒蛋白NGAL转染HL-60细胞。我们之前表明，在未分化的HL-60细胞中，NGAL被分选到嗜天青颗粒中并与髓过氧化物酶共定位。我们在此表明，当这种转染的HL-60细胞分化为粒细胞时，新合成的NGAL不会保留在颗粒中，而是持续分泌。这表明必须存在高度特异性的机制来负责将运输小泡转移到储存颗粒中，并且HL-60细胞不仅缺乏激活特异性颗粒蛋白转录的能力，而且在成熟过程中还失去了形成储存颗粒的能力。
