Figure 4.

Ectopic expression of Ski yields opposite effects on MMP‐2 and MMP‐9 gelatinase activity in cardiac myofibroblasts. First passage (P1) primary cardiac MFB were grown to 70% confluency, serum‐deprived and infected with either Ad‐LacZ or Ad‐Ski at 50 MOI (for the MMP‐9 assay) or a range of 10 to 150 MOI (for the MMP‐2 assay) for 48 h. Untreated controls were serum‐deprived, but not infected with either virus. Concentrated conditioned media (15 μg protein/lane) from all groups were assayed for MMP activity by gelatin zymography. Native human MMP‐2 protein (5 μg) served as a positive control in MMP‐2 studies. (A) Representative gelatin zymography of concentrated conditioned media for secreted MMP‐9. (B) Histogram showing data obtained in A. Data are normalized to the control expression ± SEM. The level of secreted MMP‐9 activity was significantly elevated in response to Ski overexpression at an AdSki MOI of 50. Data are representative of the mean ± SEM where n = 3; **P ≤ 0.01 compared to untreated control and AdLacZ‐50 control values. (C) Representative gelatin zymography of concentrated conditioned media (15 μg protein/lane) from all groups for MMP‐2 activity. The level of secreted MMP‐2 activity was significantly attenuated in response to Ski overexpression at MOI of 150, relative to LacZ‐infected controls. (D) Histogram showing data obtained in Figure 4C. Data are normalized to the control expression level ± SEM. MMP‐2 activity is significantly decreased in response to AdSki treatment compared to AdLacZ treated and uninfected controls. Data are representative of the means ± SEM where n = 3. *P ≤ 0.05 compared to untreated and AdLacZ‐150 controls.