Coordinate NF-kappaB and STAT1 activation promotes development of myeloid type 1 dendritic cells

NF-κB and STAT1 are critically involved in the initiation of the inflammatory cascade. Using semi-automated imaging cytometry and fluorescent antibodies, we screened several factors for their ability to induce nuclear translocation of RelA/NF-κB and STAT1 in subsets of monocyte-derived dendritic cells (DC). Detailed kinetics and dose–response studies are presented for IL-1-, LPS-, CD40L-, IFN-γ- and IFN-α-stimulated responses. The results are consistent with the notion that simultaneous activation of both STAT1 and NF-κB pathways at the initiation of differentiation culture is required for efficient priming of IL-12 production by DC. Maturation of DC led to characteristic NF-κB and STAT1 distribution and response patterns. During the resting stage, DC differentiated under the presence of IFN-γ showed sustained STAT activation and remained responsive to LPS. By contrast, PGE₂-supplemented DC could be characterized by negligible responses to LPS and IFN-γ and a remarkable NF-κB response to CD40L. STAT1 pathway was suppressed in PGE₂-supplemented cells. We conclude that the magnitude and temporal kinetics of the nuclear shift of STAT1 and NF-κB in myeloid DC are associated with IL-12p70 production and are dependent on the nature of the stimulating factors and the polarization state of cells.