Cell type-specific regulation of fetal fibronectin expression in amnion: Conservation of glucocorticoid responsiveness in human and nonhuman primates

The appearance of oncofetal fibronectin (FFN) in cervical and vaginal secre tions is predictive of human labor. Levels of FFN in amnion increase with t he onset of labor in rhesus monkeys. Since glucocorticoid (GC) levels in se rum and amniotic fluid increase in association with parturition, we compare d GC-mediated regulation of FFN expression in cultures of amnion epithelial cells and fibroblasts isolated from human and baboon amnions. Cells were m aintained with and without dexamethasone (DEX), and levels of FFN in the co nditioned media were determined by ELISA. We observed that DEX treatment su ppressed FFN levels in both human and baboon amnion epithelial cells, where as it increased FFN levels in amnion fibroblasts. DEX treatment reduced FFN revels in cytotrophoblasts from human placenta and increased FFN levers in placental fibroblasts. Northern blots revealed that DEX reduced levers of fibronectin (FN) mRNA in amnion epithelial cells and cytotrophoblasts, wher eas it increased FN mRNA in amnion and placental fibroblasts. We conclude t hat CC differentially regulates FFN expression in epithelial and mesenchyma l cells from amnion and placenta. In addition, this pattern of cell type-sp ecific FFN regulation by CC is conserved in human and nonhuman primates and may be responsible for parturition-dependent changes in FFN expression in gestational tissues.