Transforming growth factor beta 1 modulates extracellular matrix organization and cell-cell junctional complex formation during in vitro angiogenesis

J Cell Physiol. 1990 Jan;142(1):117-28. doi: 10.1002/jcp.1041420115.

Abstract

Transforming growth factor-beta 1 (TGF-beta 1) is angiogenic in vivo. In two-dimensional (2-D) culture systems microvascular endothelial cell proliferation is inhibited up to 80% by TGF-beta 1; however, in three-dimensional (3-D) collagen gels TGF-beta 1 is found to have no effect on proliferation while eliciting the formation of calcium and magnesium dependent tube-like structures mimicking angiogenesis. DNA analyses performed on 3-D cell cultures reveal no significant difference in the amount of DNA or cell number in control versus TGF-beta 1 treated cultures. In 2-D cultures TGF-beta 1 is known to increase cellular fibronectin accumulation; however, in 3-D cultures no difference is seen between control and TGF-beta 1 treated cells as established by ELISA testing for type IV collagen, fibronectin, and laminin. In 3-D cultures there is increased synthesis and secretion of type V collagen in both control and TGF-beta 1 treated cultures over 2-D cultures. Even though an equal amount of type V collagen is seen in both 3-D conditions, there is a reorganization of the protein with concentration along an organizing basal lamina in TGF-beta 1 treated cultures. EM morphological analyses on 3-D cultures illustrate quiescent, control cells lacking cell contacts. In contrast, TGF-beta 1 treated cells show increased pseudopod formation, cell-cell contact, and organized basal lamina-like material closely apposed to the "abluminal" plasma membranes. TGF-beta 1 treated cells also appear to form junctional complexes between adjoining cells. Immunofluorescence using specific antibodies to the tight junction protein ZO-1 results in staining at apparent cell-cell junctions in the 3-D cultures. Northern blots of freshly isolated microvascular endothelium, 2-D and 3-D cultures, using cDNA and cRNA probes specific for the ZO-1 tight junction protein, reveal the presence of the 7.8 kb mRNA. Western blots of rat epididymal fat pad endothelial cells (RFC) monolayer lysates probed with anti-ZO-1 label a 220 kd band which co-migrates with the bonafide ZO-1 protein. These data confirm and support the hypothesis that TGF-beta 1 is angiogenic in vitro, eliciting microvascular endothelial cells to form tube-like structures with apparent tight junctions and abluminal basal lamina deposition in three-dimensional cultures.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Communication / drug effects
  • Cell Division / drug effects
  • Cells, Cultured
  • Endothelium, Vascular / cytology*
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / ultrastructure
  • Extracellular Matrix / drug effects*
  • Extracellular Matrix / ultrastructure
  • Intercellular Junctions / drug effects*
  • Intercellular Junctions / ultrastructure
  • Microscopy, Electron
  • Neovascularization, Pathologic / pathology*
  • Organelles / ultrastructure
  • Rats
  • Rats, Inbred Strains
  • Transforming Growth Factors / physiology*

Substances

  • Transforming Growth Factors