Downregulation of notch signaling pathway in late preterm and term placentas from pregnancies complicated by preeclampsia.

Preeclampsia (PE) is a major cause of maternal mortality and morbidity, affecting 3-5% of all pregnancies. The Notch signaling pathway plays an important role during placental development, activating several target genes. Defects in the Notch pathway have adverse effect on placentation. The aim of this study was to investigate the expression of receptors NOTCH1,-2,-3,-4, ligands DLL1,-3,-4, JAG1,-2 and target genes HEY1,-2 in placental tissue samples from 20 late preterm or term pregnancies complicated by PE versus 20 normal pregnancies. mRNA levels of the studied molecules were measured by quantitative Real-Time PCR (qRT-PCR), while the protein expression of the intracellular domain of NOTCH2 (NICD2) and NOTCH3 (NICD3) was measured by Western Blot (WB). qRT-PCR analysis revealed that NOTCH1, NOTCH4 and DLL1 were not expressed in the placenta. On the contrary, NOTCH2, NOTCH3, DLL3, DLL4, JAG1, JAG2, HEY1 and HEY2 mRNA levels were downregulated in PE samples vs. controls (p<0.01). WB confirmed that NICD2 (p = 0.014) and NICD3 (p