Interleukin-1β (IL-1β) Induces Transforming Growth Factor-β1 (TGF-β1) Production by Rat Aortic Smooth Muscle Cells

Abstract In cultured rat aortic smooth muscle cells (RASMCs) IL-1β induced TGF-β 1 mRNA expression, which was concentration (10 pM-10 nM)- and time (2-48 h)-dependent, and sensitive to cycloheximide. The maximal increase in TGF-β 1 mRNA was 4.5 times the basal level at 10 nM of IL-1β. A parallel increase In TGF-β 1 protein in the culture medium of IL-1β-stimulated RASMCs was also observed. A detectable level of TGF-β 1 was found 8 h after stimulation and a plateau was reached at 72 h with a maximal increase of 5-fold and was inhibited by IL-1 receptor antagonist (IL-1ra). Our data demonstrate for the first time that IL-1β is a potent inducer of TGF-β 1 synthesis and release in vascular smooth muscle cells.