Paracrine communication modulates production of Wnt antagonists and COX1-mediated prostaglandins in a decidual-trophoblast co-culture model.

Wnt signalling has important roles in decidualisation, implantation and placentation. We investigated the role of decidua-trophoblast communication and Wnt signalling in the placenta using a co-culture model. Expression of a wide range of Wnt-related genes was observed in both decidual and trophoblast cells using PCR array, with remarkably similar expression profiles. Co-culture induced altered expression of several Wnt-related proteins, with the Wnt inhibitors sFPR4 and DKK1 being among the most differentially expressed genes. Media concentrations of sFRP4 and DKK1 were increased with co-culture, coincident with a decrease in canonical Wnt signalling activity. Expression of PTGS1 mRNA and COX1 protein was also increased with co-culture as were media PGE2 concentrations; these changes were replicated by addition of exogenous DKK1 and sFRP4. Collectively, these data suggest that paracrine interactions between decidua and trophoblast stimulate Wnt antagonist secretion leading to increased placental prostaglandin production. This may be important for implantation and placental function.