Patterns of sialylation in differentiating rat decidual cells as revealed by lectin histochemistry

Lectin histochemistry was used to demonstrate changes in the surface glycan distribution of uterine stromal cells as they differentiate to form decidual cells. Decidualization was induced in hormone-treated, ovariectomized rat uteri by needle scratch. Uterine tissue from days 2 to 8 of deciduoma development was examined with a panel of lectins specific for terminal non-reducing structures in N- and O-linked classes of glycoprotein glycan, including alpha 2,3- and alpha 2,6-linked sialic acid residues. Immunostaining for desmin was used to identify decidual cells. An increase in N-linked glycans associated with the cell surface and recognized by lectins from Phaseolus vulgaris (leukoagglutinin) (l-PHA), Pisum sativum (PSA) and Triticum vulgaris (WGA) was found during the early growth of decidual cells. As decidualization progressed regionally from the antimesometrial to mesometrial uterus, an increase in alpha 2,3-linked sialic acid residues was followed by a loss of the alpha 2,6-linked form. The results suggest that as stromal cells differentiate, glycoprotein biosynthesis and glycosyl transferase activity are altered. These changes in patterns of glycosylation may give rise to altered decidual cell-matrix and cell-cell interactions during differentiation and play a role in the modulation of decidual cell interactions with trophoblast during early placentation.