SOCS1 overexpression inhibits and its knockdown enhances MMPs and ADAMTS-4 production in SW1353 cells. The effect of SOCS1 over- or underexpression on MMPs secretion by SW1353 cells after IL-1β stimulation was investigated. After 24 hours, SOCS1-overexpressing SW1353 cells (white hatched bar) produced significantly lower amounts of MMP-1 (A), MMP-3 (B), and MMP-13 (C) than control SW1353 cells (white bar). Conversely, SOCS1-knockdown SW1353 cells (gray hatched bar) produced significantly higher amounts of MMP-1 (A), MMP-3 (B), and MMP-13 (C) than controls (gray bar). SOCS1 overexpression and knockdown showed a similar effect of SOCS1 on ADAMTS-4 transcript expression after IL-1β stimulation (10 ng/ml, D). Data were expressed as the mean ± SEM (n = 3). OE, overexpression; KD, knockdown; *P ≤ 0.005; †P < 0.05 by Mann–Whitney test.