title: The involvement of CD146 and its novel ligand Galectin-1 in apoptotic regulation of endothelial cells.
abstract: CD146 is a highly glycosylated junctional adhesion molecule, expressed on human vascular endothelial cells and involved in the control of vessel integrity. Galectin-1 is a lectin produced by vascular cells that can binds N- and O-linked oligosaccharides of cell membrane glycoproteins. Because both CD146 and Galectin-1 are involved in modulation of cell apoptosis, we hypothesized that Galectin-1 could interact with CD146, leading to functional consequences in endothelial cell apoptosis. We first characterized CD146 glycosylations and showed that it is mainly composed of N-glycans able to establish interactions with Galectin-1. We demonstrated a sugar-dependent binding of recombinant CD146 to Galectin-1 using both ELISA and Biacore assays. This interaction is direct, with a K(D) of 3.10(-7) M, and specific as CD146 binds to Galectin-1 and not to Galectin-2. Moreover, co-immunoprecipitation experiments showed that Galectin-1 interacts with endogenous CD146 that is highly expressed by HUVEC. We observed a Galectin-1-induced HUVEC apoptosis in a dose-dependent manner as demonstrated by Annexin-V/7AAD staining. Interestingly, both down-regulation of CD146 cell surface expression using siRNA and antibody-mediated blockade of CD146 increase this apoptosis. Altogether, our results identify Galectin-1 as a novel ligand for CD146 and this interaction protects, in vitro, endothelial cells against apoptosis induced by Galectin-1.
authors.affiliation: Aix-Marseille Université, INSERM, UMR-S 1076, 13385 Marseille, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jouve
authors.forename: Nicolas
authors.initials: N
authors.lastname: Despoix
authors.forename: Marion
authors.initials: M
authors.lastname: Espeli
authors.forename: Laurent
authors.initials: L
authors.lastname: Gauthier
authors.forename: Sophie
authors.initials: S
authors.lastname: Cypowyj
authors.forename: Karim
authors.initials: K
authors.lastname: Fallague
authors.forename: Claudine
authors.initials: C
authors.lastname: Schiff
authors.forename: Françoise
authors.initials: F
authors.lastname: Dignat-George
authors.forename: Frédéric
authors.initials: F
authors.lastname: Vély
authors.forename: Aurélie S
authors.initials: AS
authors.lastname: Leroyer
mesh_terms: D017209:Apoptosis; D051929:CD146 Antigen / Q000737:chemistry*; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000166:cytology*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005347:Fibroblasts / Q000378:metabolism; D037483:Galectin 1 / Q000378:metabolism*; D037501:Galectin 2 / Q000378:metabolism; D005786:Gene Expression Regulation; D006031:Glycosylation; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007700:Kinetics; D008024:Ligands; D011134:Polysaccharides / Q000737:chemistry; D011485:Protein Binding; D034741:RNA, Small Interfering / Q000378:metabolism; D020349:Surface Plasmon Resonance; D014162:Transfection
chemical_list: D051929:CD146 Antigen; D018076:DNA, Complementary; D037483:Galectin 1; D037501:Galectin 2; D008024:Ligands; D011134:Polysaccharides; D034741:RNA, Small Interfering