[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.