EXPRESSION OF A DISINTEGRIN-LIKE PROTEIN IN CULTURED HUMAN VASCULAR CELLS AND IN-VIVO

Metalloproteinase-like, disintegrin-like, and cysteine-rich. proteins (MDCs) are potential novel regulators of cell-cell and cell-matrix int eractions, as well as of matrix degradation, We have asked whether MDC s are expressed in cultured diploid vascular cells, and have identifie d MDC 15 in human aortic smooth muscle (SMC) and umbilical vein endoth elium (HUVEC), MDC 15 mRNA is expressed at higher levels in HUVECs tha n in SMCs. In cultured SMCs, MDC 15 mRNA levels are not regulated by P DGF or IGF-I or by adherence to different extracellular matrices, Nor is regulation of MDC 15 mRNA levels observed in HUVEC monolayers at di fferent cell densities, after multi-scratch wounding, or after treatme nt with TNF-alpha, LPS, or thrombin, However, differences in proteolyt ic processing of MDC 15 are observed in different HUVEC strains, In co ntrast to cultured arterial cells, MDC 15 protein is not expressed in vivo in normal vessels, but is up-regulated in lesions of atherosclero sis, These findings suggest that MDC 15 may be a potential regulator o f vascular cell function and may be involved in the development of les ions of atherosclerosis.