Association of Wnt2 and sFRP4 Expression in the Third Trimester Placenta in Women With Severe Preeclampsia

Abstract

The Wnt signaling pathway is a conserved pathway and plays a crucial role in regulating trophoblast functions. Abnormal expression of the Wnt pathway may result in the dysfunction of the trophoblast that can contribute to the pathogenesis of preeclampsia (PE). However, published data regarding the association between Wnt pathway and PE in human pregnancy is rare. The aims of this study were to investigate the expression pattern of Wnt2 and secreted frizzled-related protein 4 (sFRP4) in the third trimester human placenta and to evaluate the relationship between changes in placental Wnt2 and sFRP4 expression and severe PE. The expression of Wnt2 and sFRP4 in normal and severe PE placentas was examined using immunohistochemistry (IHC), real-time polymerase chain reaction, and Western blot. Compared to the controls, the relative expression of Wnt2 messenger RNA was remarkably downregulated in the PE placentas, while there was no significant difference in sFRP4 between the 2 groups. The IHC indicated that Wnt2 and sFRP4 were expressed predominantly in the villous syncytiotrophoblast and the extravillous trophoblast, whereas Wnt2 in the control group showed higher staining intensity than in the PE group, and sFRP4 in the PE group had a higher staining intensity than in the control group. Furthermore, the results of the Western blots were consistent with the IHC. The Wnt signaling pathway was detected in human third trimester placentas, and the decreased placental expression of Wnt2 and increased placental expression of sFRP4 may be associated with the pathogenesis of severe PE.