Fig. 3. Elastin controls migration of vascular smooth muscle cells. (A) Eln^+/+ and Eln^-/- vascular smooth muscle cells migrate to tropoelastin in a concentration-dependent manner, indicating that tropoelastin is a specific and direct stimulus for vascular smooth muscle cell localization. In addition, Eln^-/- cells consistently migrated at a higher rate than Eln^+/+ cells, suggesting that the autocrine production of elastin by Eln^+/+ cells reduces their chemotaxis to external stimuli. (B) Tropoelastin inhibits vascular smooth muscle cell migration to the chemotactic growth factor PDGF. A modified Boyden chamber assay was used for all experiments to determine the total number of migrated cells in 15 randomly selected high power microscope fields (HPF). Data shown are the mean±s.e.m. from three independent wells.