Figure 4.

OB-Runx2 deficiency promotes MDSC expansion and activation in BM via IL-1β and IL-6. The number and activation state of MDSCs isolated from BM of OB-Runx2+/+ and OB-Runx2−/− mice were determined by FACS. A, Representative FACS plot (left) and quantification (right) of MDSCs (Gr1+ CD11bhi) (n=6 mice/group). B, Expression of ARG1, iNOS, and IL-10 in MDSCs from OB-Runx2−/− mice relative to that in OB-Runx2+/+ mice, as determined by FACS (n=6 mice/group). C, MDSCs isolated from BM of OB-Runx2+/+ mice were cultured in medium mixed in a 1:1 ratio with PBS, BMS from OB-Runx2+/+ or OB-Runx2−/− mice, or BMS from OB-Runx2−/− mice pretreated for 30 minutes with neutralizing antibodies against IL-1β (20 μg/ml) or IL-6 (20 μg/ml) or isotype IgG control. After 48 hours in culture, MDSCs were counted in triplicate by a Z1 Dual Threshold Coulter Counter (Beckman Coulter) (n=3/culture group). D, Expression of ARG1, iNOS, and IL-10 in MDSCs from each group in (C) relative to that in the cells cultured with PBS, as determined by FACS (n=3/culture group). Data are presented as mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001.