The Differentiation of HL-60 Cells Causes to Lose their Ability to Express TNF mRNA

Kim, Jung Hyun; Han, Soo Jin; Park, Choon Sik; Chung, Il Yup

Abstract

It is well known that HL-60 cell, a human promyelocytic line, is differentiated into eosinophil-like cells in the presence of butyric acid, and thus the differentiated HL-60 cells have been used as a model system to study irnmunological properties of peripheral eosinophils which are thought to be terminally differentiated. To study whether HL-60 cells alter their capability of expressing cytokines during differentiation to eosinophil-like cells, we examined TNF mRNA levels in HL-60 cells treated with butyric acid by Ribonuclease Protection Assay (RPA). HL-60 cells were incubated for 3 days in the presence of butyric acid (0.5 mM), and stimulated with PMA and lipopolysaccharide (LPS). The levels of TNF mRNA decreased by 50 % and 95 % upon one and two days of post-treatment of butyric acid, respectively. The decreased pattern in TNF mRNA levels was also observed in HL-60 cells that have been treated with retinoic acid known as an inducer for differentiation of them. In accordance with these results, prominent azurophilic granules typical in eosinophils appeared in the cytoplasm of the differentiated HL-60 cells. The decreased expression of TNF mRNA was not attributable to the presence of serum, since increasing concentrations of serum had no effect. Furthermore, interleukin-5 (IL-5), which is known to be involved in activation and trafficking of eosinophils in vivo and in vitro, failed to affect TNF mRNA production when it was used in place of butyric acid. These data suggest that the differentiated HL-60 cells may have immunological resemblance to eosinophils in that they weakly produce the cytokine mRNA.