The effect of calcium mobilization on LPS-induced IL-1 beta production depends on the differentiation stage of the monocytes/macrophages.
The role of elevated intracellular calcium concentration [Ca2+]i in the LPS-induced activation of interleukin-1 beta (IL-1 beta) production was examined in cells representing different stages of myeloid differentiation (undifferentiated monocytic leukaemia cell line THP-1, THP-1 cells induced to adherent, macrophage-like cells by phorbol ester treatment and normal peripheral blood-derived adherent monocytes). LPS did not elevate the [Ca2+]i as measured by the Fura-2 fluorescence technique. When these cells were stimulated with LPS in the presence of the calcium ionophore A23187, a clear increase in the IL-1 beta protein production was observed in the undifferentiated THP-1 cells but not in the more differentiated cell types. This ionophore-induced increase was also seen in the IL-1 beta mRNA levels. Thus these data confirm the previous findings demonstrating that elevation of [Ca2+]i is not involved in the LPS-dependent signal transmission. However, the LPS-induced signals are greatly potentiated by the elevated [Ca2+]i, but only in undifferentiated monocytic cells.
Hurme
M
M
Department of Bacteriology, University of Helsinki, Finland.
Viherluoto
J
J
Nordström
T
T
D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis*; D008070:Lipopolysaccharides; D008262:Macrophage Activation; D008264:Macrophages / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D009693:Nucleic Acid Hybridization; D012313:RNA / Q000032:analysis / Q000302:isolation & purification
D007375:Interleukin-1; D008070:Lipopolysaccharides; D000001:Calcimycin; D012313:RNA; D002118:Calcium