FIGURE 6.

MED14 knockdown in U937 cells abolishes GC-sparing effects of VitD on MKP-1 induction by DEX. Base-line and VitD-induced MED14 mRNA (A) and protein (B and C) expression are inhibited by MED14 siRNA but not control siRNA in U937 cells. Following the transfection of siRNA, U937 cells were cultured in RPMI 1640 medium for 24 h. Cells were treated with or without VitD in the presence of 60 pg/ml GM-CSF to examine MED14 mRNA (A) and MED14 protein (B) expression 6 and 24 h post-stimulation, respectively. C, -fold changes in the densitometry readings of MED14 protein expression normalized to β-actin were calculated in comparison with vehicle control set as 1. D, MED14 siRNA inhibits VitD induction of MKP-1 mRNA and VitD enhancement of DEX-induced MKP-1 mRNA in the U937 cell line. Cells were treated with 60 pg/ml GM-CSF and VitD or vehicle control for 21 h, followed by DEX (10 nm) treatment for 3 h. MKP-1 mRNA levels were tested by real-time PCR and were normalized to β-actin mRNA. Values represent mean ± S.E. (error bars).