Macrophage (M) foam cell formation is a characteristic event that occurs in the early stage of atherosclerosis. To examine the roles of activin-A, a member of the transforming growth factor-j3 superfamily, and follistatin, the binding protein for activin-A, in M4> function, we investigated their effects on foam cell formation of THP-1 M0s. When THP-1 M(j)S were treated with activin-A (5 nmol/L), foam cell formation and cellular cholesteryl ester accumulation were decreased. This downregulation

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... as paralleled by a reduction in cell association and degradation of acetylated LDL. The inhibitory effect of activin-A on cell association and degradation was dose dependent, and the effect was blocked by concomitant addition of follistatin. Activin-A (5 nmol/L) also decreased the Bmax for acetylated LDL and scavenger receptor mRNA expression. Follistatin showed an effect opposite to that of