Tropoelastin inhibits vascular calcification via 67-kDa elastin binding protein in cultured bovine aortic smooth muscle cells.

In cases of vascular calcification, the expression of tropoelastin is down-regulated, which most likely decreases elastic fiber formation. However, the function of tropoelastin in vascular calcification remains unknown. We investigated whether tropoelastin affects the induction of vascular calcification. Calcification was induced using inorganic phosphate in cultured bovine aortic smooth muscle cells. The increase in tropoelastin due to the addition of recombinant bovine tropoelastin (ReBTE; 1 or 10 microg/ml) or beta-aminopropionitrile (25 microg/ml) significantly inhibited calcification at day 6, as assessed by the o-cresolphthalein complexone method. The addition of an elastin-derived peptide, VGVAPG peptide (0.1-1,000 nM), inhibited calcification at day 6 in a dose-dependent manner. In addition, these responses of beta-aminopropionitrile, ReBTE, and VGVAPG peptide were confirmed using von Kossa staining. To examine whether ReBTE inhibited calcium deposition via the elastin binding protein, lactose and elastin-specific antibody were used. The combination of lactose (20 mM) or this antibody (50 microg/ml) with ReBTE (10 microg/ml) attenuated the inhibition of calcification. These results suggest that increased tropoelastin inhibits vascular calcification in this model via the interaction between tropoelastin and elastin binding protein.