Stephen P. Massia

β3-Integrins Rather Than β1-Integrins Dominate Integrin-Matrix Interactions Involved in Postinjury Smooth Muscle Cell Migration

Background—Smooth muscle cell (SMC) migration is a vital component in the response of the arterial wall to revascularization injury. Cell surface integrin–extracellular matrix interactions are essential for cell migration. SMCs express both β1- and β3-integrins. In this study, we examined the relative functional roles of β1- and β3-integrin–matrix interactions in postinjury SMC migration. Methods and Results—Flow cytometry and fluorescence microscopy of migrating SMCs immunostained with anti-β1 and anti-αvβ3/5 antibodies (Abs) revealed expression of both β1- and β3-integrins, with β1 observed as linear streaks and β3 found in focal contacts. In a scrape-wound migration assay, anti-β1 Abs (92.0±10.7% of control, P=.1) and 0.5 mmol/L linear RGD (105±5% of control, P=.2) did not alter SMC migration at 48 hours after injury. β3-Blockade, however, via Abs (anti-β3/5 35.7±4.5% of control, anti-β3 61±12% of control, both P<.001) and cyclic RGD (0.5 mmol/L) (12±10% of control, P<.001) decreased migration. Neither...