Lactosaminoglycans are involved in uterine epithelial cell adhesion in vitro

The cell type specificity of glycoconjugate synthesis between the epithelial and stromal cells of the uterus is described. Lactosaminoglycans (LAGs) constituted a major fraction of the cell-associated glycoconjugates synthesized by epithelial, but not stromal, cells. Furthermore, LAGs comprised the bulk (greater than 90%) of glycoconjugates that could be released from epithelial cell surfaces by proteases. Several lines of evidence indicate that the epithelial cell-specific lactosaminoglycans appear to interact directly with a cell surface galactosyltransferase (GalTase). This includes the observation that agents that perturb galactosyltransferase function also interrupt epithelial cell adhesion and cause LAG release from the cell layer. In addition, LAGs are galactosylated when UDP-[3H]galactose is added to intact epithelial cell layers. Interference with cell surface GalTase activity with alpha-lactalbumin or UDP-galactose, but not other agents, specifically interrupted epithelial cell adhesion; however, the same agents had absolutely no effect on stromal cells. Collectively, these studies describe the novel occurrence of lactosaminoglycans on cell surfaces in an adult tissue other than hematopoietic cells and provide evidence for cell type-specific involvement of lactosaminoglycans in uterine cell adhesion processes.