Bidirectional Regulation of Smooth Muscle Cell Proliferation by IFN-γ

Abstract

We studied the effects of interferon gamma (IFN-γ), a T-cell lymphokine, on the proliferation and chemotaxis of vascular smooth muscle cells (SMC). Recombinant human IFN-γ dose-dependently inhibited the proliferation of SMC cultured in the presence of 20% fetal calf serum. It also inhibited PDGF-induced chemotaxis of SMC. Similar concentrations of IFN-γ induced DNA-synthesis of SMC cultured in mitogen-depleted medium for 5 days. The inhibition and the stimulation of SMC proliferation were accompanied by concomitant decrease and increase in the number of PDGF receptors. Our study indicated that IFN-γ is a bidirectional regulator of SMC proliferation.