LECTURE Modulation of Elastin Expression and Cell Proliferation in Vascular Smooth Muscle Cells in vitro

Elastin expression in cultured vascular smooth muscle cell (VSMC) was found to be enhanced by potent inhibitors of VSMC proliferation including minoxidil, heparin and retinoic acid. By contrast, elastin expression was declined by potent stimulators of VSMC proliferation like epidermal growth factor, high K+, angiotension II and phorbol ester. To elucidate the relationship between elastin expression and cell proliferation, the elastin expression in the different cell growth states brought by cell-synchronizing culture or suspension culture, a culture system independent of potent modulators of VSMC proliferation. Elastin was found to be expressed maximally at GO and minimally at G2/M phases, suggesting that cell growth state regulates elastin expression in VSMC culture. Synthetic elastin peptide VPGVG or its polymeric form (VPGVG)n enhanced VSMC proliferation, which resulted in the reduction of elastin expression. The results suggests that elastin fragment regulates VSMC proliferation. These correlation between elastin expression and cell growth state may play an essential role in elastin metabolism under the normal and diseased conditions. (Keio J Med 45 (1): 58-62, March 1996)