Overexpression of A1, an NF-κB-inducible anti-apoptotic Bcl gene, inhibits endothelial cell activation

A1 is an anti-apoptotic bcl gene that is expressed in endothelial cells (EC) in response to pro-inflammatory stimuli. We show that in addition to protecting EC from apoptosis, A1 inhibits EC activation and its associated expression of proinflammatory proteins by inhibiting the transcription factor nuclear factor (NF)-kappa B, This new anti-inflammatory function gives a broader dimension to the protective role of A1 in EC, We also show that activation of NF-kappa B is essential for the expression of A1. Taken together, our data suggest that A1 downregulates not only the pro-apoptotic and pro-inflammatory response, but also its own expression, thus restoring a quiescent phenotype to EC. (C) 1999 by The American Society of Hematology.