Fig. 1. Correlation between MT1-MMP expression and VSMC contractile-protein expression. (A) MT1-MMP levels were assessed by immunoblotting protein extracts from the aortas of 4-day-old wild-type (+/+) and MT1-MMP^–/– (–/–) mice, and from the corresponding isolated VSMCs at the indicated passages using antibodies against the catalytic domain of MT1-MMP. Extracts from human HT-1080 fibrosarcoma cells that expressed constitutively activated MT1-MMP were analyzed as controls side-by-side with the tenth-passage VSMCs. β-tubulin served as a loading control. Mean values of relative MT1-MMP levels are expressed below each lane (n=2). Relative mobilities of the molecular-mass markers are indicated in kDa. (B) Aortic frozen sections of 4-day-old wild-type (MT1-MMP^+/+) and MT1-MMP^–/– mice, and the corresponding isolated passage-1 and -10 VSMCs from the aortas of wild-type and MT1-MMP^–/– mice, were analyzed for SMA by immunofluorescence. Nuclei were visualized by DAPI. Note the high SMA expression in the tenth-passage MT1-MMP^–/– VSMCs. Scale bars: 20 µm.