HEK293 cells were co-transfected with TNF-α and ADAM28 vectors in addition to either scrambled siRNA or three different human ADAM28 (A28) siRNA. After 48hrs, ADAM28 mRNA (A), ADAM28 protein (B, C and D), TNF-α shedding (E; top panel) and membrane bound pro-TNF-α protein levels (E; bottom panel) were determined. Data expressed as mean ± SEM (A, C, D and E). *p<0.05 compared to scrambled siRNA (scrambled); n=3–6 from at least 2 independent experiments.