Next, we knocked down NFAT5 mRNA levels in MDM using an siRNA that suppresses both NFAT5 mRNA and NFAT5 protein levels [31]. As shown in Figure 2, transfection of the siRNA specific for NFAT5 reduces NFAT5 mRNA levels in both MTb-uninfected (p = 0.048) and MTb-infected (p = 0.021) MDM as compared to transfection of control GFP siRNA into MTb-uninfected or -infected MDM (Figure 2B). We note that although siRNA normally is effective for 48–72 hours in cell lines that divide rapidly, in human MDM, which are non-dividing cells, siRNA to host factors remains detectable and functional up to at least 15 days post-transfection [47].