Abstract MP29: Preeclampsia Dysregulates The MicroRNA Profile Of Small Extracellular Vesicles From Endothelial Colony Forming Cells

Abstract

Umbilical cord blood contains an enriched population of endothelial colony forming cells (ECFCs), which are vital for de novo vasculogenesis and vessel homeostasis. Previously, our lab has shown that preeclampsia (PE), a hypertensive disorder of pregnancy seen after 20 weeks of gestation, causes perturbations in how the ECFCs function, including decreased vasculogenic potential, and could cause increased risks to the infant later in life. Developing methods to monitor and restore the changes in these cells could significantly improve fetal outcomes. One such method is monitoring small extracellular vesicles (sEVs), which contain a cargo of RNA, DNA, and proteins that can influence other cell’s function through paracrine signaling. By quantifying microRNA (miRNA) expression in the PREC sEVs, we aim to identify potential biomarkers and determine their ability to restore PREC functionality. ECFCs from healthy (ECFCs) and preeclamptic (PRECs) pregnancies were isolated from cord blood. Three low passage (P4-5) and three high passage (P7-8) cell lines were used for each condition. The supernatant from each cell type was collected, filtered, and ultracentrifuged to isolate the sEVs. The miRNA isolated from the sEVs was quantified using the Nanostring nCounter. Results were assessed using nSolver for data normalization, R for differential expression, and MetaCore for pathway analysis. High and low passage ECFC sEVs were added to the media of the PRECs (1x10 8 sEVs/mL). After 24 hours of treatment, a tube formation assay was run. There is significant dysregulation of miRNA in the PRECs compared to the ECFCs. Most of the miRNA were associated with proliferation, gene transcription, migration, and angiogenesis. In addition, there are some PE associated functions affected including endometrial remodeling, decidualization, and embryonic development. After treating the PRECs with ECFC exosomes of high and low passages, the PRECs had a more distinct network with clear loops and more branching compared to the untreated control. PE causes a distinct miRNA profile in PRECs. This data suggests that the dysregulated profile could be used as biomarkers to assess the progression of PE as some miRNA was identified in high or low passage only as well as provide a method for earlier diagnosis. In addition, treatment with healthy sEVs improving PREC tube forming ability indicates their potential as a therapeutic for enhancing vascularization post-PE and improving perinatal outcomes.