MUC1 expression is elevated in severe preeclamptic placentas and suppresses trophoblast cell invasion via β1-integrin signaling.

Context: Preeclampsia is a pregnancy-specific disorder that features insufficient extravillous trophoblast (EVT) invasion. We have previously shown that MUC1 expression in human placenta increases with gestational age and inhibits choriocarcinoma cell invasion.

Objective: Here, we studied whether MUC1 expression in preeclamptic placentas is dysregulated and the mechanism of EVT invasion regulated by MUC1.

Design: MUC1 expression in severe preeclamptic placentas and gestational age-matched control placentas was analyzed by real-time RT-PCR, Western blot analysis, and immunohistochemistry. The effects of MUC1 expression on cell-matrix adhesion, invasion, and cell signaling were studied in HTR8/SVneo EVT cells.

Results: We found that MUC1 mRNA and MUC1 protein were significantly up-regulated in severe preeclamptic placentas when compared with the gestational age-matched control placentas. Immunohistochemical analyses showed increased expression of MUC1 in the syncytiotrophoblast and EVT of severe preeclamptic placentas. In addition, MUC1 overexpression suppressed cell-matrix adhesion and invasion of EVT cells. Importantly, our data showed that MUC1 overexpression inhibited β1-integrin activity and phosphorylation of focal adhesion kinase, whereas the surface expression of β1-integrin was not significantly changed.

Conclusions: Our findings suggest that MUC1 is overexpressed in severe preeclamptic placentas and that MUC1 overexpression suppresses EVT invasion mainly via modulating β1-integrin signaling.