Dystroglycan Expression in Human Placenta: Basement Membrane Localization and Subunit Distribution Change Between the First and Third Trimester

Objectives: This study describes the distribution of dystroglycan (DG) in human placenta, membranes, and uterine decidua. Study design: Dystroglycan expression was characterized by Western blotting, immunohistochemistry, and immunofluorescence microscopy using human tissues and cultured cells. Results: Both alpha-DG and beta-DG are expressed in the term syncytiotrophoblast, and alpha-DG is localized to the basement membrane. In first-trimester chorionic villi, alpha-DG and beta-DG are localized to the periphery of the cytotrophoblast. Expression varies in term fetal membranes. alpha-Dystroglycan is not detectable in choriocarcinoma cells or HTR cells, but beta-DG is present in both normal and cleaved forms. Conclusion: Dystroglycan is expressed at high levels in human trophoblasts, and localization of the alpha- and beta-subunits varies with gestational age and trophoblast differentiation. Because DG expression inversely correlates with invasiveness in many cancers, its pattern of expression in trophoblasts suggests a possible function in inhibition of placental invasion.