Regulated expression of cadherin-11 in human epithelial cells: a role for cadherin-11 in trophoblast-endometrium interactions?

Cadherin-11 is a novel member of the cadherin supergene family. Cadherin-11 expression is localized to mesenchymal tissue and specific regions of the neural tube during mouse embryogenesis. Here we report that cadherin-11 is spatiotemporally expressed in the epithelial cells of the human placenta. Cadherin-11 mRNA levels were low in freshly isolated cytotrophoblast cells but increased as the cytotrophoblast cells aggregated and fused to form syncytiotrophoblast cells in vitro. The increase in cadherin-11 mRNA levels was concomitant with a decrease in E-cadherin expression. Cadherin-11 was localized to the syncytial trophoblast and extravillous cytotrophoblasts, but not the villous cytotrophoblasts of the human placenta by immunohistochemistry. As both of the former cell types have intimate interactions with the endometrium, we examined cadherin-11 expression in the human endometrium. Cadherin-11 was detected in the glandular and surface epithelium of the endometrium at all stages of the menstrual cycle. However, cadherin-11 was abundant only in the stroma in the late secretory stage of the menstrual cycle. The accumulation of cadherin-11 in the stroma correlated with decidualization. Taken together, our observations demonstrate that cadherin-11 is expressed in certain epithelial cell lineages and suggest the possibility that cadherin-11 plays an important role in mediating trophoblast-endometrium interactions.