Figure 2.

Increased stiffness promotes DDR1 (discoidin domain receptor-1) expression and osteochondrocytic differentiation in wild-type (WT) vascular smooth muscle cells (VSMCs) with long-term in vitro calcification. A, WT and knockout (KO) VSMCs grown on 5 or 100 kPa substrates were cultured in calcifying media for 12 d before lysis and immunoblot (n=3). B–F, Densitometry quantification of (B) DDR1 and (C–F) osteochondrocytic marker expression. *P<0.05, **P<0.01, ***P<0.001. Bars represent means±SEM. B–F, Statistical analysis was performed by 2-way ANOVA with Bonferroni post hoc test. BMP-2 indicates bone morphogenetic protein-2; OPN osteopontin; Runx2, Runt-related transcription factor 2; and Sox, SRY (sex-determining region Y)-box 9.