EXPRESSION OF FOLLISTATIN, AN ACTIVIN-BINDING PROTEIN, IN VASCULAR SMOOTH-MUSCLE CELLS AND ARTERIOSCLEROTIC LESIONS

Activin-A has a mitogenic effect on vascular smooth muscle cells (SMCs ) and is produced by monocyte/macrophage lineage cells. Here, we studi ed the expression of follistatin, an activin-binding protein, in both A10 cells, a rat aortic SMC line, and vascular SMCs derived from adult rat aorta. Follistatin mRNA was detected in these cells by Northern b lot analysis. Ligand blot and immunoblot analyses demonstrated that fo llistatin was produced in the conditioned medium at a higher level by A10 cells than by SMCs. Furthermore, immunostaining and in situ hybrid ization of the arteriosclerotic lesions showed that follistatin was hi ghly expressed in the diseased artery, where abnormal proliferation of SMCs occurred. We suggest that follistatin is produced by vascular SM Cs and is involved in the course of atherogenesis.