Regulation of Fibronectin by Platelet-Derived Growth Factors in Cultured Rat Thoracic Aortic Smooth Muscle Cells.
Induction of fibronectin (FN) gene expression by platelet-derived growth factor (PDGF) isoforms in rat thoracic aortic smooth muscle cells (SMC) was examined. PDGF-BB enhances FN levels in SMC cultures in a time- and concentration-response fashion. PDGF-AA and PDGF-AB show no effect on FN levels. The effects of insulin and insulin-like growth factor-I (IGF-I) on PDGF-BB-induced FN levels were examined. No additivity of FN levels is observed between PDGF-BB and insulin and/or IGF-I. Experiments also show that PDGF-BB enhances FN mRNA levels, implying that acquisition of additional FN mRNA units accounts for the increase in FN levels. Induction of FN and FN mRNA levels by PDGF-BB could be one of the initial events in vascular SMC proliferation and extracellular matrix expansion, leading to atherosclerosis and hypertension. Copyright 1995 S. Karger AG, Basel
Lo
C.-S.
CS
Department of Physiology, Uniformed Services University of the Health Sciences, Bethesda, Md., USA.
Tamaroglio
T.
T
Zhang
J.
J