The effect of growth factors, cytokines, and extracellular matrix proteins on fibronectin production in human vascular smooth muscle cells

Abstract

Purpose: Although 60% to 80% of the mature intimal hyperplastic plaque is composed of extracellular matrix (ECM) proteins, little is known about the factors that stimulate smooth muscle cells (SMCs) to produce these proteins. A major component of the ECM protein is fibronectin. Thus we studied fibronectin production and its response to various growth factors, cytokines, and other ECM proteins that are released at the time of vascular injury. Methods: Quiescent cultured human SMCs were stimulated for varying intervals with increasing concentrations of agonist. Fibronectin in the cell medium was assayed by immunoblotting with a fibronectin-specific antibody. Results: After 72 hours of stimulation, transforming growth factor-β (10 ng/mL) had the most profound effect on fibronectin production (9.6- ± 2.1-fold; P < .05). Time course studies of fibronectin production up to 72 hours revealed kinetics that varied with each agonist. Transforming growth factor- β stimulated significant early production of fibronectin, whereas fibronectin production in response to epidermal growth factor and collagen type I was initially modest but increased with time. The effect of angiotensin II did not become evident until 72 hours. Conclusion: Cytokines, growth factors, and matrix proteins have varying quantitative effects on ECM protein production by human vascular SMCs. Knowledge of the factors that influence ECM protein production may allow for the design of specific inhibitors that can prevent intimal hyperplasia.