103. Dysregulated circulating microRNAs in preeclampsia: The role of miR-574-5p and miR-1972 in endothelial dysfunction

Introduction MicroRNAs are small non-coding RNAs responsible for post-transcriptional regulation of gene expression. MicroRNAs might be involved in the pathogenesis of endothelial cell dysfunction of preeclampsia. Objective Compare circulating microRNA concentrations in early-onset preeclampsia with healthy pregnancy. Subsequently determine if the differentially expressed microRNAs contribute to endothelial cell dysfunction in vitro. Methods Total RNA was isolated from plasma EDTA samples of early-onset preeclamptic patients (n = 10) and gestational age-matched healthy pregnant women (n = 10). MicroRNA expression was measured by miRNA 3.1 arrays (Affymetrix) and validated by RT-RT-PCR. Subsequently, human umbilical vein endothelial cells (HUVEC) were transfected (lipofectamine RNAiMAX), with microRNA mimics (Invitrogen) of the 3 most significantly upregulated microRNAs in preeclampsia. Tube formation, wound healing, and proliferation assays were performed to study endothelial cell function. Microarray (Affymetrix) on pooled RNA samples of transfected HUVEC was done and validated by RT-RT-PCR. Results 41 microRNAs were differentially expressed (p 0.01, fold change > 1.2 or -1.2) in preeclamptic women compared to healthy pregnant women. The top 3 upregulated microRNAs were miR-1972, miR-574-5p and miR-4792-3p; the top 3 downregulated microRNAs were miR-548a-3p, miR-874 and miR-451. Transfection of HUVEC with the miR-574-5p mimic decreased the wound healing capacity after 12 h (66%), and reduced proliferation of HUVEC (32%); transfection with the miR-1972 mimic reduced the tube formation capacity (number of loops formed decreased 19%). Using these assays no effects of the miR-4793-3p mimic on endothelial cell function were found. Array and RT-RT-PCR data revealed that the miR-574-5p mimic significantly decreased the expression of the proliferation marker MKI67. Discussion Differentially expressed microRNAs during preeclampsia might affect endothelial cell function. The negative effects of the microRNA mimics on proliferation and tube formation might indicate decreased proliferation and angiogenesis capacity of endothelial cells during preeclampsia. These microRNAs thus might be key modulators of endothelial dysfunction during preeclampsia.