MSCs were treated with IFNγ, TNFα, or both for 24 h., and STAT1 expression was determined by real time PCR (A). MSCs transfected with siRNA specific for STAT1 or a scrambled siRNA control were tested after 72 h. for STAT1 expression by real time PCR (B) or by Western blotting analysis (C), or siRNA-transfected MSCs were stimulated with IFNγ, TNFα, or both 48 h after transfection, incubated for an additional 24 h, and the expression of IL-6, iNOS, CCL5 and CXCL1 was determined by real time PCR (D).