Figure 4. Extracellular S100A4 (S100 calcium‐binding protein A4) enhances MMPs expression in mouse vascular smooth muscle cells (VSMCs) and regulates VSMC proliferation and migration in vitro.
A, Bar graphs showing the levels of Mmp2, Mmp9, and Mmp13 mRNA in mouse VSMCs incubated with different concentrations (0–0.1 μg/mL) of recombinant mouse S100A4 protein for 16 hours. The expression level of Mmp2 increased at concentrations between 0.02 and 0.1 μg/mL, whereas the expression levels of Mmp9 and Mmp13 increased at a concentration of 0.1 μg/mL. B, Bar graph showing the proliferation of mouse VSMCs treated for 48 hours with different concentrations (0–1.0 μg/mL) of recombinant mouse S100A4 protein. Cell proliferation was enhanced by treatment with S100A4 at concentrations higher than 0.1 μg/mL. C, Bar graph showing the chemoattractant activity of S100A4 for mouse VSMCs using a chemotaxis assay. VSMCs' migration to the opposite compartment containing 1 μg/mL recombinant S100A4 was greater than VSMCs' migration to the compartment containing the control medium. *P<0.05, **P<0.01. MMP indicates matrix metalloproteinase; and WST, water‐soluble tetrazolium salt.