Dendritic cell maturation occurs through the inhibition of GSK-3β

Dendritic cell (DC) maturation results in changes in antigen processing and presentation, governing the fate of adaptive immunity. Understanding the intracellular signaling pathways governing DC maturation is therefore critical. In this study, we observed that the kinase, GSK-3β, is present in its active form in resting immature DCs isolated from the spleen and bone marrow of mice. Induction of DC maturation using GM-CSF, IL-4 and TNF-α resulted in GSK-3β inhibition, as reflected by increased phosphorylation of Serine 9 on the kinase, and concomitant stabilization of its substrate, β-catenin. Treatment of immature DCs with a GSK-3β inhibitor increased cell surface expression of CD80, CD86 and CD40 on DCs, enhancing their ability to present antigen and activating IL-2 secretion by T cells. GSK-3β inhibition also parallels dendritic cell maturation in vivo. Our results show that GSK-3β signaling controls DC maturation and suggest that this kinase could be manipulated to modulate adaptive immunity.