Hirata R K, Chen S T, Weil S C
Department of Pathology and Cell Biology, Cardeza Foundation, Thomas Jefferson University Medical College, Philadelphia, Pennsylvania 19107.
Hematol Pathol. 1993;7(4):225-38.
The granule proteins are among the most abundant and characteristic proteins of myeloid cells. They are essential for the antimicrobial activity of these cells and they provide important markers for the differentiation stage of the myeloid series and for the diagnosis of myeloid leukemias. In acute promyelocytic leukemia (APL) there is high production of myeloperoxidase, and its cytochemical detection as well as the t(15;17) chromosomal translocation are important markers in the diagnosis of this acute myelogenous disease. The expression of other granule protein genes in APL has not been systematically determined. We have used the reverse transcriptase-polymerase chain reaction (RT-PCR) method to determine the pattern of expression of granule protein genes at the mRNA level in APL cells. We have examined the expression of the primary granule proteins defensin, myeloperoxidase, elastase, and cathepsin G; the secondary granule proteins lactoferrin, collagenase, and transcobalamin; as well as lysozyme, a protein reportedly found in both primary and secondary granules. mRNAs for all of these granule proteins were present in normal bone marrow mononuclear cells. We found that APL cells from three patients contain, in addition to myeloperoxidase mRNA, mRNAs for elastase, cathepsin G, and lysozyme. One patient had faint but detectable lactoferrin mRNA signal, but collagenase and transcobalamin mRNAs were not detectable in this patient. Defensin mRNA was found in one of the three APL patients, and all the primary granule protein mRNAs measured were found to be expressed in the APL cell line NB4. None of the secondary granule protein mRNAs measured were detectable in NB4 cells. After treatment with retinoic acid (RA), which induces neutrophil maturation of these cells, weak induction of lactoferrin and collagenase but not transcobalamin was observed. However, in view of the weak transcobalamin signal observed in normal bone marrow, the absence of transcobalamin in RA-induced NB4 cells must be interpreted with caution. Interestingly, elastase and cathepsin G mRNA disappeared after RA induction, whereas defensin and myeloperoxidase mRNAs remained present. These findings indicate that granule protein mRNAs are regulated separately and differently, and that only minimal expression of secondary granule protein genes can occur in APL cells.
颗粒蛋白是髓细胞中含量最丰富且最具特征性的蛋白质之一。它们对于这些细胞的抗菌活性至关重要，并且为髓系细胞分化阶段及髓系白血病的诊断提供重要标志物。在急性早幼粒细胞白血病（APL）中，髓过氧化物酶产量很高，其细胞化学检测以及t(15;17)染色体易位是这种急性髓细胞性疾病诊断中的重要标志物。APL中其他颗粒蛋白基因的表达尚未得到系统测定。我们使用逆转录聚合酶链反应（RT-PCR）方法来确定APL细胞中颗粒蛋白基因在mRNA水平的表达模式。我们检测了初级颗粒蛋白防御素、髓过氧化物酶、弹性蛋白酶和组织蛋白酶G；次级颗粒蛋白乳铁蛋白、胶原酶和转钴胺素；以及溶菌酶（一种据报道在初级和次级颗粒中均有发现的蛋白质）的表达。所有这些颗粒蛋白的mRNA在正常骨髓单个核细胞中均存在。我们发现，三名患者的APL细胞除了含有髓过氧化物酶mRNA外，还含有弹性蛋白酶、组织蛋白酶G和溶菌酶的mRNA。一名患者有微弱但可检测到的乳铁蛋白mRNA信号，但该患者中未检测到胶原酶和转钴胺素mRNA。在三名APL患者中的一名检测到了防御素mRNA，并且所检测的所有初级颗粒蛋白mRNA在APL细胞系NB4中均有表达。在NB4细胞中未检测到所检测的任何次级颗粒蛋白mRNA。用维甲酸（RA）处理诱导这些细胞向中性粒细胞成熟后，观察到乳铁蛋白和胶原酶有微弱诱导，但转钴胺素没有。然而，鉴于在正常骨髓中观察到的转钴胺素信号微弱，RA诱导的NB4细胞中缺乏转钴胺素必须谨慎解读。有趣的是，RA诱导后弹性蛋白酶和组织蛋白酶G mRNA消失，而防御素和髓过氧化物酶mRNA仍然存在。这些发现表明颗粒蛋白mRNA受到不同且独立的调控，并且APL细胞中次级颗粒蛋白基因仅出现极少表达。
