Altered fibronectin-dependent cell adhesion by PDGF accompanies phenotypic modulation of vascular smooth muscle cells.

PDGF promotes growth of smooth muscle cells (SMCs) and induces morphological changes. We investigated the effects of PDGF on cell-matrix adhesion of SMCs. PDGF reorganized integrin distribution as well as actin filament structure. PDGF-treated cells attached more loosely to fibronectin than non-treated cells. Decreased expression of alpha-actin by PDGF was antagonized by coating culture dishes with fibronectin but not with vitronectin and laminin. The inhibition of cell adhesion by GRGDSP oligopeptide and anti-fibronectin receptor antibody led to the reduction in alpha-actin expression. These results suggest that PDGF may modulate phenotype of SMCs by altering fibronectin-integrin interaction.