P40. MIR-21 and mir-221 overexpression in placental tissue of preeclamptic patients

Abstract

Introduction Preeclampsia is a hypertensive disorder potentially leading to severe complications in mother and the fetus. Etiology of preeclampsia is multifactorial including partially genetic and immunological pathways; the process of apoptosis is also involved in the development of preeclampsia. MicroRNAs (miRNAs) - small noncoding molecules- are emerging as critical regulators of biological function (including apoptosis), and alterations to the miRNAome have been described in the context of pregnancy and PE. Objectives Goal of this work was to assess expression of pre-selected miRNAs in preeclamptic placental samples and comparison with samples from physiological pregnancies. We designed a 96-well reaction plate to analyze 21 miRNAs in duplicates described to be involved in the apoptosis regulation and expressed in placenta: pro- apoptotic miR-1, let-7c, let-7g, mir-200c, mir-143, mir-205, mir-122, mir-409-3p, mir-449, mir-708, mir-149, mir-204,mir-133 and anti-apoptotic : mir-214, mir221, mir 222, and miRNAs with both the anti-apoptotic and apoptotic targets mir29a and mir29c. Methods The normalization was performed against RNU44. The miRNAs were extracted from placental tissue obtained after delivery from both preeclamptic women and healthy controls. After stem-loop primer reverse transcription in one tube, the samples were analyzed on the plates and evaluated by delta Ct algorithm. The aberrantly expressed miRNAs were subsequently validated by TaqMan MicroRNA Assay by relative quantification with the standard curves. Results Overexpression of miRNA was observed in mir-122, mir-21, mir-221, mir-29a, mir-29c and mir-449. The validation was performed on 13 preeclamptic placental samples and 6 placental samples from physiological pregnancies; significant overexpression of mir-21 and mir-221 with p =0.0055 (CI 95% 25.2–123.47) and p =0.0047 (CI 95% 12.16–57.20) was observed, respectively. Conclusion Analysis of miRNA deregulation can help in the identification of deregulated signaling in preeclamptic placentas for detection of new, potentially usable biomarkers. Even though authors would like to point out the necessity of validation on a larger sample cohort.