OP008. Different dysregulation of placental mirnas in early- and late-onset preeclampsia.

Introduction: miRNAs are small ∼22nt RNAs, important in the fine-tuning of mRNA in many organs including placenta. Preeclampsia (PE) is a heterogenous disease which may be divided into early-onset PE, which is a more severe form with assumed placental origin, and late-onset PE, with assumed maternal origin. Objectives: The aim of this study was to investigate the differential expression of miRNAs in early and late-onset PE compared to controls using high throughput sequencing. Methods: Placentas were obtained from an ongoing biobank collection at Oslo University Hospital. 23 normotensive controls, 23 early-onset PE (delivery at gestational week <34) and 26 late-onset PE (week⩾34) samples were sequenced using Illumina sequencing technology. Differential expressed miRNAs were identified by the EdgeR package in R and predicted targets were estimated by miRWalk. Results: 3 placental miRNAs were differentially expressed between controls and late-onset PE, 4 miRNAs were differentially expressed between early- and late-onset PE and 51 miRNAs were differentially expressed between early-onset PE and controls. Combining with mRNA array data from a subgroup of the same patients, we identified predicted targets of some of these miRNAs with significant inverse correlation between the respective mRNAs/miRNAs. Conclusion: These preliminary results suggest that miRNAs in placenta could be more important in the dysregulation of mRNAs in early-onset PE than in late-onset of the disease. [Copyright &y& Elsevier]