TRANSFORMING GROWTH FACTOR-BETA-2-MEDIATED REGULATION OF C3 GENE-EXPRESSION IN MONOCYTES

In this report, we show that transforming growth factor-beta 2 (TGF-be ta 2) regulates C3 gene expression in the human monocyte cell lines, U 937 and THP-1, and human peripheral blood monocytes. Treatment of U937 or THP-1 cells with TGF-beta 2 resulted in a dose-dependent induction of C3 protein and mRNA expression. Dose-dependent increases of C3 pro tein and mRNA levels were also detected in TGF-beta 2-treated primary blood monocytes, demonstrating that TGF-beta 2 can modulate C3 express ion in nontransformed monocytes. Kinetic analysis demonstrated that TG F-beta 2-mediated induction of C3 mRNA and protein could be detected w ithin 8 hr, and the induction was continuous up to 72 hr. Exposure of cells to TGF-beta 2 for as little as 2 hr was sufficient to induce C3 expression. TGF-beta 2 did not significantly increase C3 mRNA stabilit y as determined by mRNA half-life studies. Collectively, our results d emonstrate that TGF-beta 2 regulates the expression of C3 in monocytes and suggest that TGF-beta 2 may play a role in modulating the synthes is of C3 during inflammatory responses. Copyright (C) 1996 Elsevier Sc ience Ltd.