Constitutive expression of the DNA-binding domain of Ets1 increases endothelial cell adhesion and stimulates their organization into capillary-like structures

We previously reported that the Ets1 transcription factor is expressed in e ndothelial cells during angiogenesis both in normal and pathological develo pment. We analyse here the effects of the stable expression of an Ets trans dominant negative mutant (Ets1-DB), consisting in an Ets1 protein lacking i ts transactivation domain. A retrovirus containing the Ets1-DB sequence fus ed to an IRES-Neo sequence was designed and used to infect brain capillary (IBE) and aorta (MAE) mouse endothelial cell hues, Cells expressing this Et s1 mutant were examined for proliferation, migration and adhesion, Consiste nt changes were observed on cell morphology, with increased spreading and m odifications in the organization of the cytoskeleton, and increased cell ad hesion. We investigated the ability of endothelial cells to organise into c apillary-like structures using three-dimensional gels, On Matrigel, all end othelial cell lines formed a cord-like network within 24 h, with an increas ed ability of Ets1-DB cells to spread on this substrate. In long term cultu res, IBE cells expressing Ets1-DB showed a higher capacity to form branched structures; this effect was potentiated by FGF2, These results demonstrate a role of the Ets transcription factors in the regulation of the adhesive and morphogenetic properties of endothelial cells.