P 20 The expression profile of miR-517 family members in preeclamptic placenta and circulating exosome samples

Abstract

Introduction Preeclampsia is the major cause of maternal and fetal morbidity and mortality, affecting 3–8% of pregnancies worldwide. Recent findings suggest that placenta-specific miRNAs may contribute to pregnancy-related diseases. The miR-517 family was proposed as a major contributing factor to trophoblast dysfunction. Objectives Our aim was to analyze the expression of the miR-517 family members in placenta and circulating exosome samples comparing normal (N) and preeclamptic (PE) pregnancies. Methods PE and N placenta samples were collected from C-sections and stored in RNA-later. Blood samples were drawn from each pregnant in the third trimester. Plasma was separated, and exosomes were isolated by precipitation method. Short RNAs were extracted from the diluted exosomes on column, and total-RNA was isolated from the placenta samples with TRIzol. Expression analysis was carried out by qPCR with primers specific to miR-517a/b, miR-517c, and mir-517-5p; and relative expression was calculated using the comparative Ct method. Results We found significant differences in the expression of all assessed miRNAs between PE and N pregnancies. The level of placental hsa-miR-517a/b, hsa-miR-517c, and hsa-miR-517-5p was ∼2–3 times higher, comparing affected and control groups. The deviation was more pronounced in exosomal samples since all three miRNAs were expressed 4–6-times higher in the disease group. As expected, the level of miR-517a/b and c was ∼100 times higher than the passenger strand, miR-517-5p in both types of samples. Based on these data, it can be assumed that the sorting of these miRNAs varies between affected and normal pregnancy. Conclusion Placenta-specific miRNAs are believed to play important role in the regulation of pregnancy. We found that miR-517 family members are overexpressed both in preeclamptic placenta and circulating exosome samples. It can be assumed that the sorting of these miRNAs varies between affected and normal pregnancy.