Stimulation of cell surface F1-ATPase activity by apolipoprotein A-I inhibits endothelial cell apoptosis and promotes proliferation.
OBJECTIVE
Several findings argue for a protective effect of high-density lipoproteins (HDLs) against endothelial dysfunction. The molecular mechanisms underlying this protective effect are not fully understood, although recent works suggest that the actions of HDL on the endothelium are initiated by multiple interactions between HDLs (lipid or protein moiety) and cell surface receptors. We previously showed that the mitochondrial related F(1)-ATPase is a cell surface receptor for HDLs and their main atheroprotective apolipoprotein (apoA-I). Herein we test the hypothesis that the cell surface F(1)-ATPase may contribute to the ability of apoA-I and HDLs to maintain endothelial cell survival.


RESULTS
Cell imaging and binding assays confirmed the presence of the F(1)-ATPase at the surface of human umbilical vein endothelial cells (HUVECs) and its ability to bind apoA-I. Cell surface F(1)-ATPase activity (ATP hydrolysis into ADP) was stimulated by apoA-I and was inhibited by its specific inhibitor IF(1)-H49K. Furthermore the antiapoptotic and proliferative effects of apoA-I on HUVECs were totally blocked by the F(1)-ATPase ligands IF(1)-H49K, angiostatin and anti-betaF(1)-ATPase antibody, independently of the scavenger receptor SR-BI and ABCA1.


CONCLUSIONS
This study suggests an important contribution of cell surface F(1)-ATPase to apoA-I-mediated endothelial cell survival, which may contribute to the atheroprotective functions of apoA-I.
INSERM U563, Département Lipoprotéines et Médiateurs Lipidiques, Toulouse, France.
Claudia
C
Radojkovic
Annelise
A
Genoux
Véronique
V
Pons
Guillaume
G
Combes
Hugo
H
de Jonge
Eric
E
Champagne
Corinne
C
Rolland
Bertrand
B
Perret
Xavier
X
Collet
François
F
Tercé
Laurent O
LO
Martinez
D016632:Apolipoprotein A-I / Q000502:physiology*; D017209:Apoptosis / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000502:physiology*; D006801:Humans; D006180:Proton-Translocating ATPases / Q000502:physiology*; D014471:Umbilical Veins / Q000166:cytology
D016632:Apolipoprotein A-I; D006180:Proton-Translocating ATPases