DEXAMETHASONE AND INTERLEUKIN-1 POTENTLY SYNERGIZE TO STIMULATE THE PRODUCTION OF GRANULOCYTE-COLONY-STIMULATING FACTOR IN DIFFERENTIATED THP-1 CELLS

The human monocytic leukemic cell line, THP-1, which differentiates to ward macrophages in response to phorbol 12-myristate 13-acetate (PMA) was investigated for its ability to produce granulocyte colony-stimula ting factor (G-CSF). G-CSF protein was neither produced during PMA-ind uced differentiation nor in response to dexamethasone (Dex) alone. How ever, when combined, PMA and Dex synergistically stimulated THP-1 cell s to produce G-CSF. The synergistic interaction between PMA and Dex on G-CSF production appeared to be mediated through the production of in terleukin-1 (IL-1) since neutralization of IL-1 activity completely in hibited G-CSF production. Further experiments demonstrated that in THP -1 cells pretreated with PMA, Dex potently synergized with IL-1 to sti mulate G-CSF production. (C) 1997 Academic Press.