Figure 9.

The effect of MD-2 mRNA knockdown on matrix metalloproteinase 1 (MMP-1) secretion from cells treated with lipopolysaccharide (LPS) or interferon-γ (IFN-γ) plus LPS. U937 cells were transfected with 200 nm of control or MD-2 small interfering (si) RNA for 24 hr. After the transfection, the cells were treated with or without 100 units/ml of IFN-γ for 24 hr, followed by treatment with 100 ng/ml of LPS for another 24 hr. At the end of the experiment, the cells were harvested for MD-2 mRNA quantification (a) and the medium was collected for MMP-1 quantification (b). The MD-2 and MMP-1 mRNA expression by cells transfected with control siRNA and treated with LPS was designated as 100%.