Figure 1.

IL-27 promotes osteoblast mineralization and prevents bone erosion. (a) IL-27 is a natural antagonist of IL6/11 and enables cells to coordinate a switch from STAT3 to primarily STAT1-driven cell signaling. Right panel, plot showing expression of receptors WSX1/IL27Ra and gp130 in osteoblasts and osteoclasts in mean fluorescence intensity units as assessed by flow cytometry. (b) Preosteoblast (MC3T3E1 clone 14 or pOB) mineralization as assessed by Alizarin Red staining is enhanced with IL-27 and is further augmented by addition of differentiation supplements containing ascorbic acid and beta-glycerol phosphate. Shown is osteoblastic differentiation by day 21 (OB). (c) Osteoclast (OC) formation from preosteoclasts (pOC) is inhibited by IL-27 (OC-27) even in the presence of RANKL; ^∗P < 0.05 osteoclast formation in RANKL+control (OC).