Placental expression of microRNA-17 and -19b is down-regulated in early pregnancy loss

ObjectiveFirst, to determine if microRNA-17 and -19b are expressed in villous samples at early stages of pregnancy. Second, to determine whether placental expressions of these microRNAs along with their main targets (PTEN, CREB-1, TGFβ-1 and TGFβ-RII) are altered in early pregnancy loss.Study designExpression levels of microRNAs and mRNA targets in villous samples from early pregnancy loss (n = 11) and matched normal cases (n = 20) by gestational age were determined by RT-PCR.ResultsBoth microRNA-17 and -19b were expressed in all cases of normal pregnancy. They were significantly down-regulated (relative ratios: 0.35 and 0.34 respectively) in early pregnancy loss. Their main target, PTEN mRNA, was significantly up-regulated in early pregnancy loss (relative ratio: 2.6, 95%CI: 0.2–29.8). TGF-β1, CREB-1 and TGFβ-RII were not significantly different between the two groups.ConclusionmicroRNA-17 and -19b are expressed in early stages of pregnancy. They are down-regulated in villous samples from early pregnancy loss. We suggest that these main members of the microRNA-17-92 cluster might be involved in placental invasion and its dysregulation might also be related to other conditions characterized by defective placentation.