The effect of leustroducsin B on the production of cytokines by human mesenchymal cells.

Leustroducsin B (LSN-B), a novel colony-stimulating factor (CSF) inducer, has been shown to have various biologic activities in vivo. To compare the CSF-inducing activity of LSN-B in vitro with that of the well-known cytokine inducer, interleukin-1 beta (IL-1 beta), bacterial lipopolysaccharide (LPS), and phorbol 12-myristate 13-acetate (PMA), we measured granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF levels that were induced with the stimuli in several mesenchymal cells, The results indicated that each stimulant displayed a different profile in the induction of G-CSF and GM-CSF, Next, to investigate if LSN-B induces cytokines other than G-CSF and GM-CSF, we characterized cytokines that were induced with LSN-B from bone marrow stromal cells (BMSCs), The results showed that a variety of cytokines, including G-CSF and GM-CSF, were induced in both clonal and primary BMSCs, From these results, we speculate that LSN-B induces cytokine production via a regulatory pathway distinct from that of IL-1 beta, LPS, or PMA and that this signaling of LSN-B might lead to the production of a variety of cytokines in BMSCs, In addition, from our in vitro and in vivo results, we speculate that the biologic activities of LSN-B in vivo might be based on its own cytokine-inducing activity even though the target cell type of LSN-B in vivo remains to be determined.