The C-terminal domain of A1/Bfl-1 regulates its anti-inflammatory function in human endothelial cells.

Published

Journal Article

A1/Bfl-1 is a NF-κB dependent, anti-apoptotic Bcl-2 family member that contains four Bcl-2 homology domains (BH) and an amphipathic C-terminal domain, and is expressed in endothelial cells (EC). Based on NF-κB reporter assays in bovine aortic EC, we have previously demonstrated that A1, like Bcl-2 and Bcl-xL, inhibits NF-κB activation. These results, however, do not fully translate when evaluating the cell's own NF-κB machinery in human EC overexpressing A1 by means of recombinant adenovirus (rAd.) mediated gene transfer. Indeed, overexpression of full-length A1 in human umbilical vein EC (HUVEC), and human dermal microvascular EC (HDMEC) failed to inhibit NF-κB activation. However, overexpression of a mutant lacking the C-terminal domain of A1 (A1ΔC) demonstrated a potent NF-κB inhibitory effect in these cells. Disparate effects of A1 and A1ΔC on NF-κB inhibition in human EC correlated with mitochondrial (A1) versus non-mitochondrial (A1ΔC) localization. In contrast, both full-length A1 and A1ΔC protected EC from staurosporine (STS)-induced cell death, indicating that mitochondrial localization was not necessary for A1's cytoprotective function in human EC. In conclusion, our data uncover a regulatory role for the C-terminal domain of A1 in human EC: anchoring A1 to the mitochondrion, which conserves but is not necessary for its cytoprotective function, or by its absence freeing A1 from the mitochondrion and uncovering an additional anti-inflammatory effect.

Full Text

Duke Authors

Cited Authors

  • Guedes, RP; Rocha, E; Mahiou, J; Moll, HP; Arvelo, MB; Taube, JM; Peterson, CR; Kaczmarek, E; Longo, CR; da Silva, CG; Ferran, C

Published Date

  • June 2013

Published In

Volume / Issue

  • 1833 / 6

Start / End Page

  • 1553 - 1561

PubMed ID

  • 23499873

Pubmed Central ID

  • 23499873

Electronic International Standard Serial Number (EISSN)

  • 1878-2434

International Standard Serial Number (ISSN)

  • 0006-3002

Digital Object Identifier (DOI)

  • 10.1016/j.bbamcr.2013.03.001

Language

  • eng