Identification of potential early biomarkers of preeclampsia Angelika V. Timofeeva a, * , Vladyslava A. Gusar a , Nataliya E. Kan a , Kseniya N. Prozorovskaya a , Anna O. Karapetyan a , Oleg R. Bayev a , Vitaliy V. Chagovets a , Sergei F. Kliver b, c , Daria Yu. Iakovishina c , Vladimir E. Frankevich a , Gennadiy T. Sukhikh a a Federal State Budget Institution “Research Center for Obstetrics, Gynecology and Perinatology”, Ministry of Healthcare of the Russian Federation, Oparin Street, 4, Moscow, 117997, Russia b Theodosius Dobzhansky Center for Genome Bioinformatics, Saint Petersburg State University, 41A Sredniy Avenue, St. Petersburg,199004, Russia c Ksivalue LLC, Russia article info Article history: Received 24 February 2017 Received in revised form 16 November 2017 Accepted 18 November 2017 Keywords: Preeclampsia NGS RT-PCR miRNA Placenta Blood plasma abstract Introduction: It is thought that poor placental perfusion caused by inadequate remodelling of the maternal spiral arteries leads to preeclampsia (PE). To identify novel signalling pathways that contribute to PE pathogenesis and to create prerequisites for the non-invasive diagnosis of PE before clinical manifestations of the disease, this study aimed to evaluate miRNA expression levels in the placenta and blood plasma of pregnant women. Methods: miRNA deep sequencing followed by real-time quantitative RT-PCR was applied to compare miRNA expression profiles in the placenta and blood plasma from women with early- and late-onset PE relative to the control group. Results: A more than two-fold decrease in miR-532-5p, -423-5p, -127-3p, -539-5p, -519a-3p, and -629- 5p and let-7c-5p expression levels was observed in the placenta, while a more than two-fold increase in miR-423-5p, 519a-3p, and -629-5p and let-7c-5p was observed in the blood plasma of pregnant women with PE. The above-listed miRNAs are associated with PE for the first time in this study, except for miR- 519a-3p, whose role in PE has already been postulated. Using a logistic regression, plasma samples were classified into the early-onset PE group (probability p ¼ 0.01, 80% specificity, 87.5% sensitivity and 87.5% precision) and showed increased miR-423-5p expression levels that were confirmed by the 9.8-fold up- regulation (р ¼ 0.0002498) of miR-423-5p expression observed in the blood plasma at 11e13 GW by RT- PCR in a group of pregnant women manifesting severe PE clinical signs at 28e33 GW. Conclusions: miR-423-5p may be considered a potential candidate for the early diagnosis of PE during the targeted management of high-risk pregnancies. © 2017 Elsevier Ltd. All rights reserved. 1. Introduction Preeclampsia (PE), a multisystem pathological condition that occurs in 3e5% of pregnant women, is one of the leading causes of maternal and perinatal mortality [1]. Typically, the disease mani- fests in the second half of pregnancy with a classic triad of symp- toms including hypertension, proteinuria and peripheral oedema [2]. Although the aetiology and pathogenesis of PE have not been fully elucidated, the development of PE is considered to occur following a two-step process. The first stage involves a placentation defect, probably as a result of a maladjustment of the maternal local immune response against foetal tissues [3] coupled with an abnormal differentiation of cytotrophoblast cells during their in- vasion of the spiral uterine arteries [4e7]. This symptom results in a decreased placental size and restricted utero-placental blood flow, which does not meet the needs of the growing foetus [8]. As a consequence, ischaemia/hypoxia of the placenta is followed by an increase in syncytiotrophoblast apoptosis and necrosis and by the release of microvesicles and cellular debris by the trophoblasts [9]. There is also a release of damaging factors of placental origin, such as soluble fms-like tyrosine kinase 1 (sFlt1), proinflammatory cy- tokines, antibodies to the angiotensin 1 receptor, soluble endoglin, tumour necrosis factor alpha, interleukin 1, fibronectin, and blood coagulation factor VIII into the mother's bloodstream [10]. Overall, these changes lead to the onset of the second stage of PE that occurs * Corresponding author. E-mail address: avtimofeeva28@gmail.com (A.V. Timofeeva). Contents lists available at ScienceDirect Placenta journal homepage: www.elsevier.com/locate/placenta https://doi.org/10.1016/j.placenta.2017.11.011 0143-4004/© 2017 Elsevier Ltd. All rights reserved. Placenta 61 (2018) 61e71