TY - JOUR
T1 - The C-terminal domain of A1/Bfl-1 regulates its anti-inflammatory function in human endothelial cells
AU - Guedes, Renata P.
AU - Rocha, Eduardo
AU - Mahiou, Jerome
AU - Moll, Herwig P.
AU - Arvelo, Maria B.
AU - Taube, Janis M.
AU - Peterson, Clayton R.
AU - Kaczmarek, Elzbieta
AU - Longo, Christopher R.
AU - da Silva, Cleide G.
AU - Ferran, Christiane
N1 - Funding Information:
This work was supported by NIH/NHLBI and NIH/NIDDK ; Contract grant numbers: R01 HL080130 , R01 DK063275 to CF; Contract grant sponsor: Juvenile Diabetes Research Foundation ; Contract grant number: 1-2007-567 to CF. RPG and ER are the recipient of a fellowship award from the National Council for Scientific and Technological Development (CNPq), Brazil . CRP and CRL are the recipient of T32 NRSA grant T32 HL00734 , and JMT is the recipient of a Summer Von Liebig Research Fellowship for Medical Students .
PY - 2013/6
Y1 - 2013/6
N2 - 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.
AB - 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.
KW - A1/Bfl-1
KW - Apoptosis
KW - C-terminal domain
KW - Mitochondria
KW - Nuclear Factor Kappa-B
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U2 - 10.1016/j.bbamcr.2013.03.001
DO - 10.1016/j.bbamcr.2013.03.001
M3 - Article
C2 - 23499873
AN - SCOPUS:84876071367
VL - 1833
SP - 1553
EP - 1561
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
SN - 0167-4889
IS - 6
ER -