TABLE 1.

MMP13 induction is primarily dependent on FOS family members and ATF3 following IL-1 + OSM stimulation of chondrocytes

Prior to stimulation with IL-1 (0.05 ng/ml) in combination with OSM (10 ng/ml), human chondrocytes were transfected with siRNA specific for the indicated genes, or a non-targeting control (siCon; all 100 nm), and mRNA expression levels (mean ± S.D., n = 6) of MMP13 were measured at 24 h post-stimulation, relative to siCon-treated cells, normalized to 18S rRNA. The percentage inhibition of MMP13 expression relative to IL-1 + OSM + siCon was then calculated. Statistical comparisons are versus IL-1 + OSM + siCon (Student's two-tailed unpaired t test), where ****, p < 0.0001; ***, p < 0.001; **, p < 0.01; *, p < 0.05. The data are pooled from three separate experiments, each using chondrocyte cultures from different donors.

Gene (siRNA)	MMP13
	% Inhibition	p value
	± S.E.
ATF3	42.4 (15.2)	****
cFOS	42.2 (9.5)	****
FOSB	29.8 (19.9)	**
FOSL1	39.1 (8.9)	****
IER3	18.4 (11.7)	*
IRF1	19.5 (14.8)	*
JUN	23.9 (13.3)	**
RELA	17.7 (10.9)	*