After exposure to TNF-α (100 ng/ml) and cycloheximide (20 µg/ml) (TNF/CHX), TLR4 −/− MSC showed significantly higher caspase 3/7 activity (A) and a significant reduction in monolayer resistance (B, C) (panel A, **p < 0.01 WT vs TLR4 −/− MSC, n = 6 per group; panel B and C, **p < 0.01 TLR4 −/− MSC + TNF/CHX vs unstim TLR4 −/− MSC and WT MSC + TNF/CHX, n = 4 per group).