Background: Preeclampsia (PET) and intrauterine fetal growth restriction (IUGR) are significant causes of fetal and perinatal morbidity and mortality, and are risk factors for cardiovascular disease and diabetes in adults. PET, which can lead to IUGR, is thought to arise from suboptimal placentation, possibly related to aberrant insulin-like growth factor (IGF) signaling. IGF2 mRNA binding proteins (Igf2BP) are important mediators of migration of non-malignant and malignant cells. Their role in trophoblast migration and placentation is unknown.
Objective: to investigate the expression pattern of Igf2BP in trophoblast cells throughout pregnancy.
Methods: We examined extravillous trophoblast cell line (HChEpC1b) for Igf2BP expression by real time PCR and immunoblotting. We also performed immunohistochemical staining for Igf2BP on normal placental material from all three trimesters.
Results: HChEpC1b cells express all three Igf2BP isoforms. In the first trimester Igf2BP are strongly expressed in villous trophoblast and in proliferating but not in the invading extravillous cytotrophoblast. In the third trimester strong staining of the vasculosyncytial membrane was observed at the fetal and maternal plates only, with no staining in the intervening parenchyma and extravillous trophoblast (EVT).
Conclusions: Igf2BP is expressed in villotrophoblast cells throughout pregnancy but a temporal regulation is evident in the EVT. Therefore they may play a role in trophoblast physiology. Igf2BP knockdown and HChEpC1b cell migration assays may help us understand the role of Igf2BP in trophoblast invasion.
Karen Meir1, Gilad Vainer1 and Joel Yisraeli2
1. Department of Pathology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
2. Department of Developmental Biology and Cancer Research, IMRIC ,Hebrew University of Jerusalem, Jerusalem, Israel