Distribution of Galectin-1 in Mouse Uterus During Early Pregnancy

Progesterone (P) signaling is critical for establishment and maintenance of pregnancy. Proteomic studies have identified galectin-1 (Gal-1) as a downstream target of progesterone receptor (PR). Genetically modified mice deficient for Gal-1 exhibit a higher rate of fetal loses. This indicates that beside P, Gal-1 has a pivotal role in maintaining a successful pregnancy. This study was undertaken to analyze the spatial and temporal expression of Gal-1 in mouse uterus during early pregnancy, and to examine the selective role of progesterone receptors, PRA and PRB, in Gal-1 regulation. Our analysis has shown that before and during implantation Gal-1 is present in the nucleus of stromal cells with a significantly increased expression level at the time of implantation. In contrast, during decidualization Gal-1 is localized primary in the cytoplasm of cells around the implantation site at the antimesometrial pole. Additionally, Gal-1 is found in uterine natural killer (uNK) cells on the mesometrial pole. uNK cells are specifically recruited to placental attachment sites where intensive formation of new maternal blood vessels takes place. Analysis of the cell type expressing Gal-1 and individual roles of PRA and PRB in Gal-1 regulation will be presented.