Regulation of the human placental (pro)renin receptor-prorenin-angiotensin system by microRNAs

The placental renin-angiotensin system (RAS) is important for placentation. RAS expression is greatest in early gestation. This may be due (in part) to suppression of miRNAs that target the placental RAS, but this has never been explored. In this study, human placental miRNAs were measured at 10–11 (early), 14–18 (mid), and 38–40 (term) weeks gestation, as well as in placentae from women with early- or late-onset preeclampsia (n=4/group), using an Agilent miRNA microarray (V19). All miRNAs showed a gestational increase and could influence the transgestational profile of the human placental RAS. Additionally, on the array, three miRNAs predicted to target the RAS (miR-892c-3p, miR-378c and miR-514-3p ) were overexpressed in placentae of late-onset preeclamptic women. We have identified placental miRNAs that are differentially expressed in early gestation and target RAS mRNAs. At least two suppress renin production by trophoblasts. Placental miRNAs could potentially regulate placental growth and development through actions on the placental RAS. A total of 24 primary human placental samples were used in this study, from which we were able to compare the miRNA profiles across patients with and without preeclampsia, and all across gestation. Gene expression microarray analysis was used to reveal which transcripts were differentially expressed between different gestational time points and patients with preeclampsia.