Levels of Inositol Metabolites within Normal Myeloid Blast Cells and Changes during their Differentiation towards Monocytes

• Published in: Proceedings of the Royal Society. B, Biological sciences Vol. 247; no. 1318; pp. 27 - 33
• Main Authors: Bunce, C. M., French, P. J., Patton, W. Nigel, Turnell, Andrew S., Scott, Sophy A., Michell, Robert Hall, Kirk, C. J., Brown, G.
• Format: Journal Article
• Language: English
• Published: London The Royal Society 22-01-1992
• Subjects: Abortion, Spontaneous; Blasts; Cell Differentiation - drug effects; Cell lines; Cells, Cultured; Cellular differentiation; Cellular metabolism; Chromatography, High Pressure Liquid; Cultured cells; Female; Fetus; Humans; Inositol - metabolism; Inositol Phosphates - isolation & purification; Inositol Phosphates - metabolism; Inositols; Liver - cytology; Liver - drug effects; Liver - embryology; Lymphocytes; Monocytes; Monocytes - cytology; Monocytes - drug effects; Myeloid cells; Neutrophils; Pregnancy; Tetradecanoylphorbol Acetate - pharmacology
• ISSN: 0962-8452; 1471-2954
• DOI: 10.1098/rspb.1992.0005

A homogeneous population of undifferentiated myeloid blast cells was purified from human fetal liver by rosette sedimentation of erythroblasts and macrophages, after coating these cells with monoclonal antibodies, followed by a cell elutriation step. The undifferentiated blast cells were maintained in culture, in a serum-free medium containing 1 mg 1-1 inositol, by the presence of a high concentration of interleukin-3 (100 U ml-1). This allowed equilibrium labelling of cells with [2-3H]myo-inositol and analysis of the concentrations of inositol metabolites. The myeloid blast cells contained high concentrations of an unidentified inositol metabolite, possibly sn-glycero-3-phospho-I -inositol (GroPIns, 22 µm), inositol monophosphate (InsP, 16 µm, an unidentified inositol bisphosphate (InsP2, 9.4 µm), inositol pentakisphosphate (InsP5, 37 µm) and inositol hexakisphosphate (InsP6, 31 µm ). These high concentrations are similar to those reported in the promyeloid cell line, HL60. Treatment of the blast cells with 10 nM phorbol myristate acetate (PMA) resulted in rapid differentiation of 48% of the cells towards monocytes. Notable changes in the levels of inositol metabolites included an increase in the putative GroPIns peak (to 73 µm) and decreases in the concentrations of InsP4 (from 4 µm to 1 µm) and InsP5 (to 21 µm). These changes in response to PMA, with the exception of the rise in the putative GroPIns, are similar to those reported in HL60 cells undergoing monocyte differentiation. These observations suggest that the abundant inositol polyphosphates may have an as yet unknown role in myeloid differentiation.