Interleukin-1 beta induces production of granulocyte colony-stimulating factor in human hepatoma cells

Interleukin-1 (IL-1) is a proinflammatory cytokine that participates in the activation of the acute-phase plasma protein genes in hepatic cells during infection and injury. In human hepatoma HepG2 and Hep3B cells, IL-1 beta induced production of the granulocyte colony-stimulating factor (G-CSF) in a dose-dependent manner. Activation of G-CSF gene expression was an early and transient response. In HepG2 cells, G-CSF mRNA was strongly upregulated 2 hours after IL-1 beta treatment and returned to the pretreatment level by 6 hours. The secreted G-CSF was biologically active, as shown by the induction of gene transcription through the G-CSF receptor. Maximal G-CSF activity released to culture medium occurred after 8 hours. Previous studies have shown that liver expression of G-CSF was augmented in mice challenged by inflammatory stimuli. Our data suggest that IL-1 beta mediates, at least in part, this cytokine activation program in parenchymal cells and that liver- derived G-CSF may contribute to the regulation of hematopoiesis during the acute-phase response.