Gene expression analysis of HUVEC in response to TF-binding

Introduction: Tissue factor (TF), the cofactor for factor VII/VIIa (FVII/FVIIa) and initiator of the extrinsic pathway, is transiently expressed on intravascular cells under control of cytokines and growth factors. In addition, endothelial cells express a binding site for external TF. In the present study, we investigated gene expression of endothelial cells derived from human umbilical veins (HUVEC) in response to TF-binding to identify differentially expressed genes.

Materials and methods: HUVEC were treated with recombinant relipidated TF (Innovin) versus nontreated cells, as well as TF/FVIIa versus FVIIa alone. TF binding was measured by ELISA. Gene expression profiles were examined using HG-U133 plus 2.0 arrays (Affymetrix).

Results: Gene expression analysis of HUVEC showed 148 up-regulated and 29 down-regulated genes 4h after TF binding. Notably, the genes, which were significantly up- and down-regulated, either by TF alone or by the complex of TF/FVIIa, exhibited a complete overlap, indicating that activation of endothelial cells after binding of external added TF does not depend on FVIIa as has been demonstrated for TF-expressing cells. TF-mediated regulation of gene expression of several genes, involved in regulation of apoptosis, cell adhesion, cell motility, and angiogenesis, was confirmed by qPCR. Furthermore, in case of SELE, TGFB2, TNFAIP3, TNFSF4, TNFSF18, TAGLN, CXCL1, PCF11 antibodies directed to TF clearly inhibited TF-mediated regulation of gene expression.

Conclusions: The results demonstrate that interaction of TF with HUVEC via a binding site, independent from FVIIa, may result in regulation of a variety of genes involved in arteriosclerosis, cancer, and cardiovascular diseases.