TWEAK is an endothelial cell growth and chemotactic factor that also potentiates FGF-2 and VEGF-A mitogenic activity.

Objective: TWEAK, a member of the tumor necrosis factor superfamily, binds to the Fn14 receptor and stimulates angiogenesis in vivo. In this study, we investigated Fn14 gene expression in human endothelial cells (ECs) and examined the effect of TWEAK, added either alone or in combination with fibroblast growth factor-2 (FGF-2) or vascular endothelial growth factor-A (VEGF-A), on EC proliferation, migration, and survival in vitro. We also determined whether a soluble Fn14-Fc fusion protein could inhibit TWEAK biologic activity on ECs and investigated TWEAK signal transduction in ECs.

The Fn14 cytoplasmic tail binds tumour-necrosis-factor-receptor-associated factors 1, 2, 3 and 5 and mediates nuclear factor-kappaB activation.

Fn14 is a growth-factor-inducible immediate-early-response gene encoding a 102-amino-acid type I transmembrane protein. The human Fn14 protein was recently identified as a cell-surface receptor for the tumour necrosis factor (TNF) superfamily member named TWEAK (TNF-like weak inducer of apoptosis). In the present paper, we report that the human TWEAK extracellular domain can also bind the murine Fn14 protein.