DMSO及RA对GPI-80分子表达的不同影响

以往的研究表明GPI-80的表达可能与髓系细胞的分化相关。DMSO及RA是两种不同的中性粒细胞的诱导分化剂，均可刺激HL-60白血病细胞向中性粒细胞分化。GPI-80是人糖基化磷脂酰肌醇锚糖蛋白，被认为是潜在的β2-黏合素分子依赖的白细胞黏附的调节剂，主要在人中性粒细胞上表达。本研究通过RT—PCR、流式细胞仪及Western—blot分析，检测分化细胞的GPI-80表达，并分析GPI-80的表达与CD11b及CD71表达之间的关系。结果表明GPI-80在RA诱导的类中性粒细胞上只有mRNA水平上的微弱表达，用流式细胞仪和Western—blot分析均检测不到，且RA可抑制GPI-80的表达；相反GPI-80在DMSO诱导的类中性粒细胞上有明显的表达，且随DMSO的浓度增加及诱导时间的延长而增强。GPI-80的表达出现在CD11b上调表达及CD71下调表达之后，提示GPI-80表达与DMSO诱导分化的类中性粒细胞的成熟密切相关。RA不能明确诱导GPI-80的表达，反而抑制GPI-80的表达，提示可能两者诱导HL-60细胞分化时所激活的信号传递通路不同。

Different impacts of DMSO and RA on GPI-80 expression]

Our previous studies suggested that GPI-80 expression might be associated with myeloid differentiation. Dimethyl sulfoxide (DMSO) and all-trans-retinoic acid (RA) are two main inducers that can induce HL-60 cell to differentiate down the way of neutrophilic lineage. GPI-80 is a novel member of a human glycosylphosphatidylinositol (GPI)-anchored family that has been proposed as a potential regulator of beta2-integrin-dependent leukocyte adhesion, and is expressed mainly in human neutrophils. RT-PCR, flow cytometry and western-blot assays were used to detect the GPI-80 expression on HL-60 cells induced by DMSO or RA and to analyze the relationship between GPI-80 expression and CD11b or transferrin receptor (CD71) expression. The results showed GPI-80 was slightly expressed on the level of mRNA on RA-induced HL-60 cells by RT-PCR, while using flow cytometry and western-blot assays, We could not detect any GPI-80 expression on these cells, Furthermore, RA suppressed the induction of GPI-80 expression. However, DMSO could clearly derive the GPI-80 expression and this expression correlated well with the increasing dose and duration of DMSO stimulation. GPI-80 positive cells, which were included in CD11b-strongly positive and transferrin receptor-completely negative populations, were sufficiently differentiated cells suggesting that GPI-80 expression is tightly associated with the neutrophilic maturation and can be used as a mature neutrophilic marker. RA inhibits the GPI-80 expression on DMSO induced HL-60 cells suggests that different signal conduction has been activated by DMSO and RA when they induce the HL-60 cells to the neutrophilic differentiation.