Regional Differences in Integrin Expression

Abstract—There is increasing evidence to suggest that coronary smooth muscle cells (SMCs) differ from noncoronary SMCs. As integrin adhesion molecules regulate many SMC functions, we hypothesized that differences in integrin expression on coronary and noncoronary SMCs may account for cellular differences. Analysis of integrin expression on freshly isolated porcine coronary and noncoronary SMCs revealed that coronary SMCs express significantly less α5β1 than noncoronary SMCs, whereas the expression of total β1 and that of αvβ3 are similar. Consistent with these findings, coronary SMCs demonstrated significantly less adhesion to fibronectin, compared with carotid artery SMCs. As α5β1-mediated signaling has been associated with cellular proliferation, the effects of differential α5β1 expression on cell proliferation were examined by comparing primary coronary and carotid artery SMC proliferation. Coronary SMC growth was significantly lower than that of carotid artery SMCs when plated on fibronectin or type I...