CDW49B CD29 INTEGRIN COMPLEX MEDIATES THE DIFFERENTIATION OF HUMAN ENDOTHELIAL-CELLS INTO CAPILLARY-LIKE STRUCTURES IN-VITRO/

We have investigated different beta-1 integrins (CDw49/CD29) on human umbilical vein endothelial cells (HUVEC) with regard to their roles in modifying the morphological structure of these cells on/in matrigel. The inhibition of matrigel-induced capillary formation by antibodies a gainst subunits of beta-1 integrins was examined quantitatively using a digital analyzer. Antibodies to CDw49b and CD29 (common beta chain) caused a marked inhibition of capillary formation (up to 70%) in a dos e-dependent manner, whereas antibodies to CDw49d, CDw49e and CDw49f we re less inhibitory. We also examined the appearance of HUVEC cultured in matrigel. HUVEC suspended in matrigel for 24 h formed extended cell processes which connected, resulting in the formation of a capillary network. In contrast, fibroblasts cultured in matrigel showed only bip olar extensions without cell-cell contact. After 48 h in culture in ma trigel, some HUVEC showed the capillary-unit of a lumen encircled by E C which may mimic the basic putative unit in the formation of capillar ies. However, HUVEC pretreated with antibodies to CDw49b and CD29 fail ed to form significant processes and a hollow lumen. These phenomena m ay illustrate the importance of endothelial cell-basement membrane mat rix interaction (through integrins, especially CDw49b/CD29 complex) oc curring during differentiation of endothelial cells in angiogenesis.