Calcium ionophore but not phorbol ester promotes eicosanoids release by
proliferating interleukin-3-dependent bone marrow cells
Y Shibata, PG McCaffrey, H Sato and Y Oghiso
Fujisaki Cell Center, Hayashibara Biochemical Laboratories Inc., Okayama,
Japan.
Eicosanoid release during multilineage hematopoiesis was assessed using
freshly isolated mouse bone marrow cells cultured in the presence of
interleukin-3 (IL-3) (10% WEHI-3 culture-conditioned medium). Cells that
could release prostaglandin E2 (PGE2) when stimulated with calcium
ionophore A23187, but not with phorbol ester (PMA), appeared within 4 days.
The cells harvested on day 10 released 42 ng of PGE2/10(6) cells/mL after
A23187 stimulation. Leukotriene B4 (LTB4) (4 ng/mL) was also detected after
A23187 stimulation, but there was no detectable LTC4 (less than 0.5 ng/mL).
Nonadherent bone marrow cells were isolated from 28-day cultures and
cloned. All clones were strongly IL-3- dependent. Although other growth
factors such as granulocyte colony- stimulating factor (G-CSF),
granulocyte-macrophage CSF (GM-CSF), and CSF-1 failed to promote survival
or support proliferation of the cells, three clones (11-1-A6, 3-2-D5, and
11-1-A1) showed significant increases in 3H-thymidine incorporation,
respectively, after PMA treatment for 24 hours. Surviving cells displayed
dominantly myeloid type morphology and phenotypic characteristics. The data
suggest that IL-3 is important in the formation of PGE2-producing cells. In
contrast to many macrophages (MO), neither the IL-3-dependent cell lines
nor the IL-3-cultured bone marrow cells released significant amounts of
PGE2 when stimulated with PMA or IL-3, although PMA and IL-3 both induced
translocation of protein kinase C (PKC) to the membrane fraction. The lack
of production of PGE2 and other eicosanoids by the PMA- and IL-3-
stimulated cell lines was confirmed by measuring the release of 3H-
arachidonic acid. The data suggest that in IL-3-dependent bone marrow cell
lines the activation of eicosanoid metabolism requires elevated cellular
Ca2+; PKC activation alone does not appear to be a sufficient stimulus.
Volume 76,
Issue 8,
pp. 1586-1592,
10/15/1990
Copyright © 1990 by The American Society of Hematology
