The luteotrophic function of galectin-1 by binding to the glycans on vascular endothelial growth factor receptor-2 in bovine luteal cells

J Reprod Dev. 2015;61(5):439-48. doi: 10.1262/jrd.2015-056. Epub 2015 Jul 9.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Inbred Strains
  • Binding, Competitive
  • Cattle
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Survival / drug effects
  • Cells, Cultured
  • Corpus Luteum / cytology
  • Corpus Luteum / drug effects
  • Corpus Luteum / metabolism*
  • Female
  • Galectin 1 / antagonists & inhibitors
  • Galectin 1 / genetics
  • Galectin 1 / metabolism*
  • Gene Expression Regulation, Developmental*
  • Humans
  • Lactose / analogs & derivatives
  • Lactose / metabolism
  • Luteal Cells / cytology
  • Luteal Cells / drug effects
  • Luteal Cells / metabolism*
  • Luteinization* / drug effects
  • Polysaccharides / chemistry
  • Polysaccharides / metabolism*
  • Protein Kinase Inhibitors / pharmacology
  • Protein Transport
  • Recombinant Proteins / metabolism
  • Signal Transduction / drug effects
  • Surface Properties
  • Vascular Endothelial Growth Factor Receptor-2 / agonists*
  • Vascular Endothelial Growth Factor Receptor-2 / antagonists & inhibitors
  • Vascular Endothelial Growth Factor Receptor-2 / chemistry
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism

Substances

  • Galectin 1
  • LGALS1 protein, human
  • Polysaccharides
  • Protein Kinase Inhibitors
  • Recombinant Proteins
  • Vascular Endothelial Growth Factor Receptor-2
  • Lactose