REORGANIZATION OF ENDOTHELIAL CORD-LIKE STRUCTURES ON BASEMENT-MEMBRANE COMPLEX (MATRIGEL) - INVOLVEMENT OF TRANSFORMING GROWTH-FACTOR-BETA-1

The formation of capillary-like network structures by cultured vascula r endothelial cells on reconstituted basement membrane matrix, Matrige l, models endothelial cell differentiation, the final step of angiogen esis (Kubota et al., 1988; Grant et al., 1989). When endothelial cells derived from bovine aorta and brain capillaries were plated on Matrig el, DNA synthesis was suppressed and a network oi capillary-like struc tures rapidly formed in 8-12 h. With time, the network broke down, res ulting in dense cellular cords radiating from multiple cellular cluste rs in 16-24 h. Finally, multicellular aggregates of cells were formed as the network underwent further retraction. Network regression was pr evented when either dithiothreitol (DTT) or anti-TGF-beta 1 antibodies were added during the assay. The addition of exogenous TCF-beta 1 pro moted the regression of endothelial cells into the clusters. This resp onse to TGF-beta 1 was blocked by potent serine threonine protein kina se inhibitors, H-7 and HA100. TGF-beta 1 was released from polymerized Matrigel by incubation with Dulbecco's modified eagle's medium (DMEM) in the absence of cells. The Matrigel-conditioned DMEM inhibited endo thelial DNA synthesis even in the presence of anti-TCF-beta 1 antibodi es. These results suggest that TGF-beta 1 and possibly other soluble f actors from Matrigel may be important for differentiation and remodeli ng of endothelial cells in a capillary network with possible implicati ons for wound healing and development. (C) 1994 Wiley-Liss, Inc.