title: The luteotrophic function of galectin-1 by binding to the glycans on vascular endothelial growth factor receptor-2 in bovine luteal cells.
abstract: The corpus luteum (CL) is a temporary endocrine gland producing a large amount of progesterone, which is essential for the establishment and maintenance of pregnancy. Galectin-1 is a β-galactose-binding protein that can modify functions of membrane glycoproteins and is expressed in the CL of mice and women. However, the physiological role of galectin-1 in the CL is unclear. In the present study, we investigated the expression and localization of galectin-1 in the bovine CL and the effect of galectin-1 on cultured luteal steroidogenic cells (LSCs) with special reference to its binding to the glycans on vascular endothelial growth factor receptor-2 (VEGFR-2). Galectin-1 protein was highly expressed at the mid and late luteal stages in the membrane fraction of bovine CL tissue and was localized to the surface of LSCs in a carbohydrate-dependent manner. Galectin-1 increased the viability in cultured LSCs. However, the viability of LSCs was decreased by addition of β-lactose, a competitive carbohydrate inhibitor of galectin-1 binding activity. VEGFR-2 protein, like galectin-1, is also highly expressed in the mid CL, and it was modified by multi-antennary glycans, which can be recognized by galectin-1. An overlay assay using biotinylated galectin-1 revealed that galectin-1 directly binds to asparagine-linked glycans (N-glycans) on VEGFR-2. Enhancement of LSC viability by galectin-1 was suppressed by a selective inhibitor of VEGFR-2. The overall findings suggest that galectin-1 plays a role as a survival factor in the bovine CL, possibly by binding to N-glycans on VEGFR-2.
authors.affiliation: Laboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sano
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Hashiba
authors.forename: Junko
authors.initials: J
authors.lastname: Nio-Kobayashi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okuda
mesh_terms: D000818:Animals; D017849:Animals, Inbred Strains; D001667:Binding, Competitive; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003338:Corpus Luteum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D037483:Galectin 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007785:Lactose / Q000031:analogs & derivatives / Q000378:metabolism; D008184:Luteal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D034461:Luteinization / Q000187:drug effects; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021381:Protein Transport; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013499:Surface Properties; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism
chemical_list: D037483:Galectin 1; C445499:LGALS1 protein, human; D011134:Polysaccharides; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D040301:Vascular Endothelial Growth Factor Receptor-2; D007785:Lactose