miRNA expression profiling in formalin-fixed and paraffin-embedded placental tissue samples from pregnancies with severe preeclampsia

Placental expressions of Anti-Mullerian hormone/Receptor, vascular endothelial growth factor and related microRNAs in patients with preeclampsia: a case control study

Anti-Mullerian hormone (AMH) has been implicated in the pathogenesis of preeclampsia. The present study was primarily designed to determine the placental tissue AMH, Anti-Mullerian hormone Receptor II (AMHRII), vascular endothelial growth factor (VEGF) and microRNA (miRNA) 26a/126/155/210 expressions and serum miRNA 26a/126/155/210 levels in patients with preeclampsia to examine their potential role in the pathogenesis of preeclampsia. Placental tissue samples from patients with preeclampsia (n = 20) and control subjects (n = 20) were examined by immunohistochemical staining and quantitative polymerase chain reaction (qPCR) for AMH, AMHRII, VEGF mRNA expression levels and miRNA 26a/126/155/210 expressions. Serum levels of miRNA 26a/126/155/210 were measured by qPCR. Patients with preeclampsia had lower AMH/AMHRII immunostaining, particularly in syncytiotrophoblastic cells compared to control subjects (p < 0.05). The relative mRNA expressions of AMH/AMHRII were increased (1.535 ± 0.121 and 1.155 ± 0.049 fold, p < 0.0002 and p < 0.033, respectively) and the relative mRNA expression of VEGF was decreased (4.878 ± 0.331 fold, p < 0.0002) in patients with preeclampsia compared to control subjects. The miR-26a expression was increased and miR-126 expression was decreased in serum samples of patients with preeclampsia compared to control subjects (p < 0.0002). miR-155 and miR-210 expressions were increased in serum and placental tissue samples of patients with preeclampsia compared to control subjects (p < 0.0002). In conclusion, reduced placental tissue immunostaining of AMH/AMHRII along with increased AMH/AMHRII mRNA expressions may indicate posttranscriptional dysregulation. Robust increase in expressions of hypoxia/inflammation-related miRNAs particularly miR-155 and miR-210 might have a role in this mechanistic pathway. Increased serum levels of miR 26a, 155 and 210 are potential early diagnostic markers for preeclampsia.

The role of circular RNA in preeclampsia: From pathophysiological mechanism to clinical application

Preeclampsia (PE) is a common pregnancy-induced hypertension disorder that poses a significant threat to the health of pregnant women and fetuses, and has become a leading cause of maternal, fetal, and neonatal mortality. Currently, the therapy strategy for PE is mainly prevention management and symptomatic treatment, and only delivery can completely terminate PE. Therefore, a deeper understanding of the pathogenesis of PE is needed to make treatment and prevention more effective and targeted. With the deepening of molecular etiology research, circular RNAs (circRNAs) have been found to be widely involved in various processes of PE pathogenesis. As a kind of RNA with a special "head to tail" loop structure, the characteristics of circRNAs enable them to play diverse roles in the pathophysiology of PE, and can also serve as ideal biomarkers for early prediction and monitoring progression of PE. In this review, we summarized the latest research on PE-related circRNAs, trying to elucidate the unique or shared roles of circRNAs in various pathophysiological mechanisms of PE, aiming to provide a whole picture of current research on PE-related circRNAs, and extend a new perspective for the precise screening and targeted therapy of PE.

Integration of circulating microRNAs and transcriptome signatures identifies early-pregnancy biomarkers of preeclampsia

BACKGROUND

MicroRNAs (miRNAs) have been implicated in the pathobiology of preeclampsia, a common hypertensive disorder of pregnancy. In a nested matched case-control cohort within the Vitamin D Antenatal Asthma Reduction Trial (VDAART), we previously identified peripheral blood mRNA signatures related to preeclampsia and vitamin D status (≤30 ng/mL) during gestation from 10 to 18 weeks, using differential expression analysis.

METHODS

Using quantitative PCR arrays, we conducted profiling of circulating miRNAs at 10-18 weeks of gestation in the same VDAART cohort to identify differentially expressed (DE) miRNAs associated with preeclampsia and vitamin D status. For the validation of the expression of circulating miRNA signatures in the placenta, the HTR-8/SVneo trophoblast cell line was used. Targets of circulating miRNA signatures in the preeclampsia mRNA signatures were identified by consensus ranking of miRNA-target prediction scores from four sources. The connected component of target signatures was identified by mapping to the protein-protein interaction (PPI) network and hub targets were determined. As experimental validation, we examined the gene and protein expression of IGF1R, one of the key hub genes, as a target of the DE miRNA, miR-182-5p, in response to a miR-182-5p mimic in HTR-8/SVneo cells.

RESULTS

Pregnant women with preeclampsia had 16 circulating DE miRNAs relative to normal pregnancy controls that were also DE under vitamin D insufficiency (9/16 = 56% upregulated, FDR < .05). Thirteen miRNAs (13/16 = 81.3%) were detected in HTR-8/SVneo cells. Overall, 16 DE miRNAs had 122 targets, of which 87 were unique. Network analysis demonstrated that the 32 targets of DE miRNA signatures created a connected subnetwork in the preeclampsia module with CXCL8, CXCL10, CD274, MMP9 and IGF1R having the highest connectivity and centrality degree. In an in vitro validation experiment, the introduction of an hsa-miR-182-5p mimic resulted in significant reduction of its target IGF1R gene and protein expression within HTR-8/SVneo cells.

CONCLUSIONS

The integration of the circulating DE miRNA and mRNA signatures associated preeclampsia added additional insights into the subclinical molecular signature of preeclampsia. Our systems and network biology approach revealed several biological pathways, including IGF-1, that may play a role in the early pathophysiology of preeclampsia. These pathways and signatures also denote potential biomarkers for the early stages of preeclampsia and suggest possible preventive measures.

MiR-133b regulates oxidative stress injury of trophoblasts in preeclampsia by mediating the JAK2/STAT3 signaling pathway

Preeclampsia (PE) is a pregnancy-related syndrome. Aberrant placental microRNAs (miRNAs) expression might associate with PE, including miR-133b. However, its role in the pathogenesis of preeclampsia remains elusive. Therefore, this study explored the role of miR-133b in oxidative stress injury of trophoblasts in preeclampsia (PE) by mediating the JAK2/STAT3 signaling pathway. Placental tissues were collected from PE patients to detect the expression of miR-133b and JAK2/STAT3. Then, in vitro experiments were performed on human extravillous trophoblast-derived HTR-8/SVneo cells, which were divided into Normal, hypoxia/reoxygenation (H/R), H/R + miR-NC, H/R + miR-133b inhibitor, H/R + JAK2 siRNA and H/R + miR-133b inhibitor + JAK2 siRNA groups. Cell invasion and migration abilities were detected by Transwell and wound healing assays, while apoptosis was detected by flow cytometry. The intracellular oxidative stress levels were also measured. Furthermore, the expression of miR-133b and the JAK2/STAT3 pathway was determined by qRT-PCR and Western blotting. We found that miR-133b was up-regulated, with decreases in JAK2 and p-STAT3/STAT3 in placental tissues of PE patients. Additionally, HTR8/SVneo cells in the H/R group had decreased invasion and migration abilities with increased apoptotic rates and oxidative stress levels. Moreover, the expression of miR-133b was up-regulated with decreases in p-JAK2 and p-STAT3 in H/R-treated HTR8/SVneo cells. These indicators in the H/R + miR-133b inhibitor group were ameliorated in comparison with those in the H/R group but deteriorated in the H/R + JAK2 siRNA group. Moreover, JAK2 siRNA reversed the positive effect of the miR-133b inhibitor on the invasion and migration abilities of trophoblasts. In summary, inhibiting miR-133b may improve oxidative stress injury to promote the migration and invasion of trophoblasts and suppress apoptosis by activating the JAK2/STAT3 pathway.

Overexpression of let-7b exerts beneficial effects on the functions of human placental trophoblasts by activating the ERK1/2 signaling pathway

The present work aimed to explore let-7b's molecular mechanisms that regulate the functions of placental trophoblasts and to examine placental let-7b expression in human pre-eclampsia (PE). Human trophoblast HTR-8/SVneo cells underwent transduction with control and let-7b overexpressing lentiviruses, respectively. Cell proliferation assessment utilized cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays. Apoptosis, autophagy, inflammation, epithelial-to-mesenchymal transition (EMT), and ERK1/2 signaling-associated proteins were assessed by immunoblot. Placental tissue samples were collected from women with normal pregnancy (n = 20) and PE patients (n = 14). Let-7b overexpression in HTR-8/SVneo cells remarkably induced cell proliferation and invasion, suppressed apoptosis and autophagy, and resulted in decreased tumor necrosis factorα (TNF-α) expression and increased interleukin 6 (IL-6) expression in trophoblasts. Notably, the beneficial effects of let-7b overexpression, including cell invasion and EMT, were largely reversed by treatment with U0126, an indirect ERK1/2 signaling inhibitor, in these cells. TGF-β receptor type-1 (TGFBR1) overexpression weakened let-7b's functions in ERK pathway activation and invasion in trophoblasts. Placental tissue specimens from PE cases demonstrated significantly lower let-7b expression compared with normal controls. Overexpression of let-7b exerts beneficial effects on the functions of human placental trophoblasts via ERK1/2 signaling, and placental let-7b is downregulated in human PE. These findings suggest let-7b is a promising biomarker for the prospective diagnosis and targeted therapy of PE.

Microrna analysis of human decidua mesenchymal stromal cells from preeclampsia patients

INTRODUCTION

In preeclampsia (PE), human decidua mesenchymal stromal cells (hDMSCs) are exposed to abnormally high levels of oxidative stress and inflammatory factors circulating in the maternal blood. MicroRNAs (miRNAs) have been shown to have a significant impact on the differentiation, maturation and function of mesenchymal stromal cells (MSCs). Our aim in the present study is firstly to investigate differentially expressed miRNA levels to be used as a biomarker in the early detection of PE and secondly to investigate whether those differentially expressed miRNAs in hDMSCs have an effect on the pathogenesis of PE.

METHODS

This study covers miRNA expression analysis of hDMSCs from 7 PE patient and 7 healthy pregnant women and is a preliminary study to investigate putative biomarkers. After cell culture and cell sorting, total RNA including miRNAs were isolated from hDMSCs. Let-7b-3p, let-7f-1-3p, miR-191-3p, miR-550a-5p, miR-33b-3p and miR-425-3p were used for miRNA analysis and U6 snRNA was used for normalization of the samples. MiRNA analysis was performed by droplet digital polymerase chain reaction (ddPCR) method and obtained results were evaluated statistically.

RESULTS

As a result of the analysis, it was observed that the levels of hsa-miR-33b-3p significantly (AUC: 0.93, p = 0.04, fold change: 4.5) increased in hDMSC of PE patients compared to healthy controls. However, let-7b-3p, let-7f-1-3p, miR-191-3p, miR-550a-5p, and miR-425-3p were not considered as significant because they did not meet the p < 0,05 requirement.

DISCUSSION

Within the scope of the study, it is predicted that miR-33b-3p (p = 0.004, AUC = 0.93) can be used as a biomarker in detecting PE.

A new pipeline for clinico-pathological and molecular placental research utilizing FFPE tissues

The placenta is at the core of many pregnancy pathologies, but we have limited knowledge about placental function because of two key research barriers: 1) lack of guidelines for sample collection and pathologic diagnosis; and 2) limited tools are available for molecular analysis of stored placental samples. We aimed to create a searchable, population-based placental database of pathologic diagnoses, and to validate molecular methods for gene expression studies of matching formalin fixed paraffin embedded (FFPE) placental blocks. Our database has over 1000 pregnancies coded for clinical diagnosis with corresponding FFPE blocks that are available for gene expression studies. RNA harvested from FFPE tissues is of sufficient quality for downstream applications. We successfully used this pipeline to identify FFPE placenta from term and preterm pregnancies, and compared their gene expression. The establishment of this platform, which links clinicopathological data and molecular gene expression, will increase our understanding of obstetrical diseases.

Diagnostic Potential of MicroRNAs as Biomarkers in the Detection of Preeclampsia

Preeclampsia is a multisystemic disorder that occurs in 5-8% of pregnant women and remains a leading cause of both maternal and fetal morbidity and mortality. The disease is characterized by the abnormal vascular response to placentation, but the exact pathophysiology and pathogenesis of preeclampsia remain unknown. Risk factors for preeclampsia include increased maternal age, obesity, multiple gestations, and a history of preeclampsia. Several studies have suggested that altered expression of some microRNAs (miRNAs) in placental tissue, and maternal circulation, may be associated with several types of pregnancy complications such as preeclampsia, preterm birth, and spontaneous abortion. It is assumed that these miRNAs play an important role in various cellular processes important for maintaining a healthy pregnancy, including promoting angiogenesis and the differentiation of trophoblast cells. In this review, we discuss the role of miRNAs as potential biomarkers of preeclampsia.

Information on dysregulation of microRNA in placenta linked to preeclampsia

MicroRNAs are single-stranded, non-coding RNA molecules, regulate gene expression at the post-transcriptional level. They are expressed in the human body and have a significant impact on the different processes of pathological illness. A developing placenta undergoes a series of stages after successful fertilization, such as cell division, migration, adhesion, apoptosis, and angiogenesis. MicroRNAs dysregulation in placenta has been linked to pregnancy-related complications such as preeclampsia. Therefore, it is of interest to document known information (list of microRNA) on this issue in the development of biological tools for diagnosis, treatment and prevention of the disease.

The expression of miRNA encoded by C19MC and miR-371-3 strongly varies among individual placentas but does not differ between spontaneous and induced abortions

miRNAs of the largest human miRNA gene cluster at all, i.e., C19MC, are almost exclusively expressed in the placenta. Nevertheless, only little is known about the interindividual variation of their expression and even about possible influence of gestational age, conflicting data is reported as well as for miRNAs of the much smaller miR-371-3 cluster. Our present study aims at the analyses of the expression of miRNAs from both clusters at different times of pregnancy, possible differences between placenta samples obtained from spontaneous or induced abortions in the first trimester, and the possible variation of miRNA expression at different sites within same placentas. miR-371a-3p, miR-372-3p, miR-373-3p, miR-517a-3p, and miR-520c-3p were quantified in 85 samples and miR-371a-3p was quantified in maternal serum samples taken immediately before delivery. While for miRNA-517a-3p and miR-520c-3p the expression increased with increasing gestational age, the present study revealed strong interindividual differences in the expression of miR-371-3 in full-term placental tissue as well as for miRNAs of the C19MC cluster, where the levels differed to a much lesser extent than for the former microRNAs. Also, strong interindividual differences were noted between the serum samples but differences related to the site of the placenta where the sample has been taken from were excluded. For neither of the data from placental tissue, the study revealed differences between the spontaneous and induced abortion group. Thus, the differences do not in general seem to be related to first trimester abortion. It remains to be elucidated whether or not they affect other prenatal processes.

Let-7a inhibits Bcl-xl and YAP1 expression to induce apoptosis of trophoblast cells in early-onset severe preeclampsia

Dysregulation of the MicroRNA (miR) Let-7 family has been implicated in preeclampsia (PE). Abnormal trophoblast cell proliferation and apoptosis associate with the pathogenesis of PE. The present study was designed to test the hypothesis whether let-7a could regulate the biological functions of trophoblasts and explore the mechanism how it works in the development of early-onset severe PE. The putative target genes Bcl-xl and YAP1 of let-7a were verified by luciferase assay. The roles of let-7a, Bcl-xl and YAP1 in regulating JEG-3 cell functions were examined by altering their expression with mimic, overexpression plasmids or siRNAs. The methylation status of let-7a-3 in PE was assessed by methylation-specific and bisulfite sequencing PCR assays. JEG-3 cells were treated with DNA methyltransferase inhibitor to analyze whether let-7a-3 demethylation functioned in PE. Tumor growth and cell apoptosis were measured from nude mice inoculated with JEG-3 cells overexpressing let-7a. The results revealed let-7a was highly expressed in early-onset severe PE and let-7a-3 presented a low methylation level. Functionally, let-7a upregulation could inhibit the viability and cell cycle progression but induce the apoptosis of JEG-3 cells. Bcl-xl and YAP1, target genes of let-7a, could rescue cell apoptosis induced by let-7a. The demethylation of let-7a-3 was also observed to elevate the expression of let-7a and enhance JEG-3 cell apoptosis. Let-7a inhibited tumorigenic ability of JEG-3 cells and enhanced cell apoptosis in vivo. Altogether, let-7a could enhance cell apoptosis in trophoblasts through downregulation of Bcl-xl and YAP1, which suggests that let-7a might be a key regulator in the progression of PE.

Circular RNA hsa_circ_0007121 regulates proliferation, migration, invasion, and epithelial-mesenchymal transition of trophoblast cells by miR-182-5p/PGF axis in preeclampsia

Background

Mounting evidence has revealed that abnormal expression of circular RNAs play pivotal roles in many human diseases including preeclampsia (PE). While human sapiens circular RNA 0007121 (hsa_circ_0007121) has been verified to be downregulated in human placental tissues, the underlying mechanisms were still unclear. This research aims to investigate the effect and underlying mechanisms of hsa_circ_0007121 in preeclampsia.

Methods

The expression of hsa_circ_0007121, microRNA (miR)-182-5p, and placental growth factor (PGF) was assessed by quantitative reverse transcription polymerase chain reaction in PE placentas relative to the expression in normal pregnancy placentas. After transfection, cell counting kit-8 assay was employed to detect cell proliferation. Cell migration and invasion were tested by the transwell assay. The relative level of epithelial–mesenchymal transition (EMT)-related proteins in HTR-8/SVneo cells and PGF in placentas samples were measured by western blot. The relationship between miR-182-5p and hsa_circ_0007121 or PGF was predicated by circular RNA interactome or ENCORI and verified by dual-luciferase reporter assay and RNA immunoprecipitation assay.

Results

The levels of hsa_circ_0007121 and PGF were significantly declined in PE placental tissues and HTR-8/SVneo cells, whereas miR-182-5p had an opposite result. Downregulation of hsa_circ_0007121 obviously inhibited HTR-8/SVneo cell proliferation, migration, invasion, and EMT, while upregulation of hsa_circ_0007121 promoted this process. Besides, miR-182-5p was a target gene of hsa_circ_0007121 and could target PGF. Further analysis indicated that hsa_circ_0007121 regulated the proliferation, migration, invasion, and EMT of HTR-8/SVneo cells via altering PGF expression by interacting with miR-182-5p.

Conclusion

Hsa_circ_0007121 mediated the progression of PE via miR-182-5p/PGF axis.

MSC-Secreted Exosomal H19 Promotes Trophoblast Cell Invasion and Migration by Downregulating let-7b and Upregulating FOXO1

Exosomes perform important functions for intercellular communication through extracellular signaling pathways, leading to the regulation of important biological processes, including cell proliferation, but also systemic dysfunctions such as preeclampsia (PE). However, the inhibitory effects of mesenchymal stem cell (MSCs)-derived exosomes in PE remain largely unknown. Thus, we assessed the possibility that exosomes could transport long non-coding RNA H19 and the correlation between H19 and the apoptosis of trophoblast cells. The expression of microRNA let-7b and forkhead box protein O1 (FOXO1) was characterized in placental tissues of PE patients. Gain- and loss-of-function experiments were performed to examine the roles of FOXO1 and let-7b in trophoblast cells. Interactions between let-7b and H19 as well as between let-7b and FOXO1 were confirmed by a dual-luciferase reporter assay, RNA pull-down, and RNA immunoprecipitation. HTR-8/SVneo cells were co-cultured with exosomes derived from MSCs overexpressing H19, followed by invasion, migration, and apoptosis assessments of trophoblast cells. We found that let-7b was highly expressed and FOXO1 was poorly expressed in placental tissues of PE patients. Furthermore, H19 acts as a competitive endogenous RNA against let-7b, and let-7b directly targeted FOXO1. Moreover, H19 could be transferred to trophoblast cells via MSC-secreted exosomes. MSC-derived exosomes overexpressing H19 decreased let-7b, increased FOXO1, and activated the protein kinase B (AKT) signaling pathway, thus increasing invasion and migration and inhibiting apoptosis of trophoblast cells. These results suggest that MSC-derived exosomes overexpressing H19 may be a novel direction for therapeutic strategies against PE.

MicroRNAs in Uteroplacental Vascular Dysfunction

Pregnancy complications of preeclampsia and intrauterine growth restriction (IUGR) are major causes of maternal and perinatal/neonatal morbidity and mortality. Although their etiologies remain elusive, it is generally accepted that they are secondary to placental insufficiency conferred by both failure in spiral artery remodeling and uteroplacental vascular malfunction. MicroRNAs (miRNAs) are small no-coding RNA molecules that regulate gene expression at the post-transcriptional level. Increasing evidence suggests that miRNAs participate in virtually all biological processes and are involved in numerous human diseases. Differentially expressed miRNAs in the placenta are typical features of both preeclampsia and IUGR. Dysregulated miRNAs target genes of various signaling pathways in uteroplacental tissues, contributing to the development of both complications. In this review, we provide an overview of how aberrant miRNA expression in preeclampsia and IUGR impacts the expression of genes involved in trophoblast invasion and uteroplacental vascular adaptation.

Epigenetic Biomarkers in Cardiovascular Diseases

Cardiovascular diseases are the number one cause of death worldwide and greatly impact quality of life and medical costs. Enormous effort has been made in research to obtain new tools for efficient and quick diagnosis and predicting the prognosis of these diseases. Discoveries of epigenetic mechanisms have related several pathologies, including cardiovascular diseases, to epigenetic dysregulation. This has implications on disease progression and is the basis for new preventive strategies. Advances in methodology and big data analysis have identified novel mechanisms and targets involved in numerous diseases, allowing more individualized epigenetic maps for personalized diagnosis and treatment. This paves the way for what is called pharmacoepigenetics, which predicts the drug response and develops a tailored therapy based on differences in the epigenetic basis of each patient. Similarly, epigenetic biomarkers have emerged as a promising instrument for the consistent diagnosis and prognosis of cardiovascular diseases. Their good accessibility and feasible methods of detection make them suitable for use in clinical practice. However, multicenter studies with a large sample population are required to determine with certainty which epigenetic biomarkers are reliable for clinical routine. Therefore, this review focuses on current discoveries regarding epigenetic biomarkers and its controversy aiming to improve the diagnosis, prognosis, and therapy in cardiovascular patients.

Expression profile of Let-7s in peripheral blood mononuclear cells of normal and severe preeclampsia pregnant women

HEADINGS AIM

We aimed to investigate if the let-7 s expression level in the serum of peripheral blood from pregnant women with severe pre-eclampsia and normal pregnant women is related to the incidence of severe pre-eclampsia.

METHODS

Total RNA was extracted from collected peripheral blood mononuclear cells from 20 or over weeks pregnant women diagnosed with severe pre-eclampsia (age: 31.57 ± 4.94) and normal pregnant women (age: 29.75 ± 4.6) respectively, followed by real-time PCR to examine the expression of let-7 s. Correlation between let-7 s expression level and maternal age or body mass index of the normal pregnant women were also analyzed using SPSS21.0 software.

RESULTS

Let-7a and let-7 g were significantly increased in pregnant women with severe pre-eclampsia by 4.67 fold and 2.37 fold respectively compared to the normal pregnant women, whereas there was no significant difference in let-7b and let-7i. Moreover, there was no correlation between maternal age or body mass index and the expression level of let-7a, let-7b, let-7 g, and let-7i.

CONCLUSIONS

In conclusion, let-7a and let-7 g were significantly increased in the PBMCs of severe pre-eclampsia women compared to normal controls. Moreover, their expression level was not correlated to the maternal age or body mass of patients. Our data indicated that let-7a and let-7 g may be considered as predictive markers for SPE.

The role of NUDT21 in microRNA-binging sites of EZH2 gene increases the of risk preeclampsia

OBJECTIVES

Preeclampsia (PE) is a major cause of mortality and morbidity among pregnant mothers and their fetuses worldwide. Recent studies have shown that several microRNAs (miRNAs) play crucial role in pathogenesis of PE patients; however, the mechanisms responsible for differences in miRNA function in PE largely remain to be determined.

MATERIALS AND METHODS

We studied that NUDT21 expression was markedly increased, whereas EZH2 was decreased in placental samples from patients with PE. We identified NUDT21 as an interaction partner of enhancer of zeste homologue 2 (EZH2). NUDT21 co-localized with EZH2 in the human trophoblast cell line, HTR-8/SVneo and NUDT21 was shown to bind to EZH2 in RNA immunoprecipitation assays. NUDT21 has previously been reported to be involved in alternative polyadenylation; thus, the interaction between NUDT21 and EZH2 may play an important role in the crosstalk between alternative polyadenylation (APA) and miRNA-mediated gene silencing in PE.

RESULTS

In the human trophoblast cell line HTR-8/SVneo, loss-of-function assays indicated that knockdown of NUDT21 suppressed cell proliferation, migration and tube formation. Furthermore, functional studies showed that NUDT21 elongated the 3'-UTR of mRNAs thereby exposing more miRNA binding sites (including miR138 and miR363), which enhanced the efficiency of miRNA-mediated gene silencing and promoted EZH2 binding.

CONCLUSIONS

This is the first report about the relationship of NUDT21 and EZH2. The data indicate that the aberrant expression of NUDT21 contributes to PE by targeting 3'-UTR of EZH2 mRNA. These findings may provide novel targets for future investigations into therapeutic strategies for PE.

Extraction of RNA from formalin-fixed, paraffin-embedded equine placenta

Archived formalin-fixed, paraffin-embedded (FFPE) samples represent a valuable resource for the determination of gene expression for physio/pathological conditions. In the present study, we validated a protocol for the extraction of RNA from FFPE samples collected from healthy and diseased equine placenta. The quality and quantity of the extracted RNA from the FFPE and matching RNAlater™-preserved samples and expression levels of common housekeeping genes and reference microRNAs were evaluated. Precision of the expression data was evaluated by comparing relative expression of CYP19A1 and HSD3B1 in FFPE and RNAlater™ samples. The median RNA concentration recovered from FFPE samples was 316.8 ng/mm³ of tissue (ranging between 61.6 and 917.4 ng/mm³ ), average RNA integrity number was 2.3 ± 0.9 (mean ± standard deviation), and 84% of samples had RNA fragments longer than 200 nucleotides (DV₂₀₀ ). RNA concentrations and C_T values for GAPDH, ACTB, miR-8908a and miR-369 in FFPE samples were significantly correlated (r = -0.8, -0.7, -0.4 and -0.4, respectively; p < 0.001). Expression pattern of normalized CYP19A1 and HSD3B1 in paired FFPE and RNAlater™ samples was significantly correlated (r = 0.97 for CYP19A1 and HSD3B1; p < 0.001). This study demonstrates that RNA can be extracted from FFPE equine placental tissue and used for downstream transcriptomic analysis. Similar RNA expression patterns were obtained using RNAlater™ and FFPE tissue samples.

Roles of microRNAs in preeclampsia

Preeclampsia (PE) is a complex disorder that is characterized by hypertension and proteinuria after the 20th week of pregnancy, and it causes most neonatal morbidity and perinatal mortality. Most studies suggest that placental dysfunction is the main cause of PE. However, genetic factors, immune factors, and systemic inflammation are also related to the pathophysiology of this syndrome. Thus far, the exact pathogenesis of PE is not yet fully understood, and intense research efforts are focused on PE to elucidate the pathophysiological mechanisms. MicroRNAs (miRNAs) refer to small single-stranded and noncoding molecules that can negatively regulate gene expression, and miRNA regulatory networks play an important role in diverse pathological processes. Many studies have confirmed deregulated miRNA in pregnant patients with PE, and the function and mechanism of these differentially expressed miRNA are gradually being revealed. In this review, we summarize the current research about miRNA involved in PE, including placenta-specific miRNA, their predictive value, and their function in the development of PE. This review will provide fundamental evidence of miRNA in PE, and further studies are necessary to explore the roles of miRNA in the early diagnosis and treatment of PE.

Cardiac remodeling and pre-eclampsia: an overview of microRNA expression patterns

Pre-eclampsia (PE) is strongly associated with heart failure (HF) later in life. During PE pregnancy, the left ventricle undergoes concentric remodeling which often persists after delivery. This aberrant remodeling can induce a molecular signature that can be evaluated in terms of microRNAs (miRNAs) and which may help to explain the associated increased risk of HF. For this review, we performed a literature search of PubMed (National Center for Biotechnology Information), identifying studies on miRNA expression in concentric remodeling and on miRNA expression in PE. The miRNA data were stratified based on origin (isolated from humans or animals and from tissue or the circulation) and both datasets compared in order to generate a list of miRNA expression patterns in concentric remodeling and in PE. The nine miRNAs identified in both concentric remodeling and PE-complicated pregnancy were: miR-1, miR-18, miR-21, miR-29b, miR-30, miR-125b, miR-181b, miR-195 and miR-499-5p. We found five of these miRNAs (miR-18, miR-21, miR-125b, miR-195 and miR-499-5p) to be upregulated in both PE pregnancy and cardiac remodeling and two (miR-1 and miR-30) to be downregulated in both; the remaining two miRNAs (miR-29b and miR-181b) showed upregulation during PE but downregulation in cardiac remodeling. This innovative approach may be a step towards finding relevant biomarkers for complicated pregnancy and elucidating their relationship with remote cardiovascular disease. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

MiR-616-3p modulates cell proliferation and migration through targeting tissue factor pathway inhibitor 2 in preeclampsia

OBJECTIVES

Despite improvements in diagnosis and treatment, preeclampsia (PE) continues to pose a significant risk of maternal and foetal morbidity and mortality if not addressed promptly. An increasing number of studies have suggested that tissue factor pathway inhibitor 2 (TFPI2) acts as a suppressor gene, possibly inhibiting multiple serine proteases affecting cell proliferation and migration. It plays an essential role in the occurrence and development of PE, but the pathogenesis remains unclear.

MATERIALS AND METHODS

In our research, we performed western blotting, immunohistochemistry and qPCR assays to investigate TFPI2 and miR-616-3p expression in preeclamptic placental tissues. Cell assays were performed in HTR-8/SVneo and JEG3 cell lines. Cell proliferation and migration events were investigated by MTT, EdU and transwell assays. In conjunction with bioinformatics analysis, luciferase reporter assays were performed to elucidate the mechanism by which miR-616-3p binds to TFPI2 mRNA.

RESULTS

We established that TFPI2 protein levels were significantly upregulated in PE placental tissues. In addition, we found that miR-616-3p binds specifically to the 3'-UTR region of TFPI2 mRNA. Furthermore, miR-616-3p knockdown or TFPI2 overexpression substantially impaired cell growth and migration, whereas miR-616-3p upregulation or TFPI2 knockdown stimulated cell proliferation and migration. This miR-616-3p/TFPI2 axis was also found to affect the epithelial-mesenchymal transition process in PE.

CONCLUSIONS

Our results demonstrated that TFPI2 plays a vital role in the progression of PE and might provide a prospective therapeutic strategy to mitigate the severity of the disorder.

Maternal Circulating microRNAs and Pre-Eclampsia: Challenges for Diagnostic Potential

Pre-eclampsia (PE) is a common hypertensive disorder of pregnancy with a significant impact on maternal and neonatal mortality and morbidity. While the pathogenesis of PE has been well described, identification of a biomarker(s) with robust predictive utility in identifying women at the highest risk of developing the condition has yet to be identified. In the search for diagnostic markers, those that may be obtained from the circulation are preferred alternatives to those derived from organ tissue samples. Because of their stability in plasma, microRNAs (miRNAs) have been explored as biomarkers in a host of disease states, although there is comparably little literature available on the circulating miRNAome of PE. This article provides a narrative review on the current state of knowledge on miRNAs associated with PE. Literature on circulating miRNAs is presented and the challenges to developing the diagnostic and prognostic utility of miRNAs in this context is discussed.

Increased miR-223 expression in foetal organs is a signature of acute chorioamnionitis with systemic consequences

Acute chorioamnionitis, frequently observed in preterm placentas, is a major risk factor for the development of infection and non-infection-related adverse perinatal outcomes. MicroRNAs play important roles in immune cell development and function as well as in the development of cancers and neurologic diseases. We sought to investigate the changes in microRNA-223 (miR-223) expression and the functional significance of the changes in miR-223 expression in foetal organs in the presence of acute chorioamnionitis. Using formalin-fixed, paraffin-embedded (FFPE) tissue samples from foetal or neonatal autopsy cases, which are the most practical option to study the changes in several organs simultaneously, miR-223 expression profiles in foetal thymus, lung and liver were compared between cases with and without acute chorioamnionitis. Total RNA was extracted from FFPE specimens and qRT-PCR was conducted. miR-223-3p expression levels in foetal thymus (2.55-fold), lung (1.93-fold) and liver (1.70-fold) were significantly higher in cases with acute chorioamnionitis than in those without. Transfection of pre-miR-223-3p in Jurkat cells and luciferase assay and ribonucleoprotein immunoprecipitation followed by qRT-PCR analysis confirmed the binding of miR-223 to the 3' untranslated region (3'UTR) of forkhead box O1 (FoxO1) mRNA and the regulation of FoxO1 by miR-223. We report for the first time that foetuses with inflammation in the chorioamniotic membranes show increased expression of miR-223 in the thymus, lung and liver. Furthermore, FoxO1 is a target of miR-223. These findings suggest that post-transcriptional regulation of genes by miR-223 is a component of the foetal inflammatory response, which has systemic consequences in the foetus.

Small Molecule, Big Prospects: MicroRNA in Pregnancy and Its Complications

MicroRNAs are small, noncoding RNA molecules that regulate target gene expression in the posttranscriptional level. Unlike siRNA, microRNAs are "fine-tuners" rather than "switches" in the regulation of gene expression; thus they play key roles in maintaining tissue homeostasis. The aberrant microRNA expression is implicated in the disease process. To date, numerous studies have demonstrated the regulatory roles of microRNAs in various pathophysiological conditions. In contrast, the study of microRNA in pregnancy and its associated complications, such as preeclampsia (PE), fetal growth restriction (FGR), and preterm labor, is a young field. Over the last decade, the knowledge of pregnancy-related microRNAs has increased and the molecular mechanisms by which microRNAs regulate pregnancy or its associated complications are emerging. In this review, we focus on the recent advances in the research of pregnancy-related microRNAs, especially their function in pregnancy-associated complications and the potential clinical applications. Here microRNAs that associate with pregnancy are classified as placenta-specific, placenta-associated, placenta-derived circulating, and uterine microRNA according to their localization and origin. MicroRNAs offer a great potential for developing diagnostic and therapeutic targets in pregnancy-related disorders.

Blood laboratory testing for early prediction of preeclampsia: chasing the finish line or at the starting blocks?

Preeclampsia (PE) affects 2-8% of pregnancies worldwide, thus representing an important cause of maternal and neonatal morbidity, up to death. Many studies have been designed to identify putative biomarkers for accurate and timely diagnosing PE, but only some of them were focused on specific and sensitive biomarkers for early prediction of this life-threatening condition. In particular, some prospective studies aimed to investigate the predictive role of circulating biomarkers before 20 weeks of gestation in the general pregnant population yielded conflicting results. This article is hence centered on results obtained in studies investigating the predictive performances of angiogenic, anti-angiogenic, inflammatory, endocrine, and epigenetic biomarkers. The available evidence suggests that angiogenic and anti-angiogenic molecules, in particular the sFlt1:PlGF ratio, may be considered the biomarkers with the best diagnostic performance in the second trimester. However, doubts remain about their use in clinical settings before the 20th gestational week. Even lower evidence is available for other biomarkers, due to the fact that some positive results have not been confirmed in ensuing investigations, whereas unresolved analytical issues still contribute to make their clinical reliability rather questionable. Differential expression of microRNAs seems also a promising evidence for early prediction of PE, but additional research and well-designed prospective studies are needed to identify and validate routine predictive tests. KEY MESSAGES Preeclampsia affects 2-8% of pregnant women worldwide, thus remaining one of the leading causes of maternal and neonatal morbidity and mortality. Several studies have investigated the predictive role of circulating biomarkers before 20th week of gestation with conflicting results. Additional research and well-designed prospective studies are needed to identify and validate predictive tests in clinical practice.

Systematic Review of Micro-RNA Expression in Pre-Eclampsia Identifies a Number of Common Pathways Associated with the Disease

Background

Pre-eclampsia (PE) is a complex, multi-systemic condition of pregnancy which greatly impacts maternal and perinatal morbidity and mortality. MicroRNAs (miRs) are differentially expressed in PE and may be important in helping to understand the condition and its pathogenesis.

Methods

Case-control studies investigating expression of miRs in PE were collected through a systematic literature search. Data was extracted and compared from 58 studies to identify the most promising miRs associated with PE pathogenesis and identify areas of methodology which could account for often conflicting results.

Results

Some of the most frequently differentially expressed miRs in PE include miR-210, miR-223 and miR-126/126* which associate strongly with the etiological domains of hypoxia, immunology and angiogenesis. Members of the miR-515 family belonging to the imprinted chromosome 19 miR cluster with putative roles in trophoblast invasion were also found to be differentially expressed. Certain miRs appear to associate with more severe forms of PE such as miR-210 and the immune-related miR-181a and miR-15 families. Patterns of miR expression may help pinpoint key pathways (e.g. IL-6/miR-223/STAT3) and aid in untangling the heterogeneous nature of PE. The detectable presence of many PE-associated miRs in antenatal circulatory samples suggests their usefulness as predictive biomarkers. Further progress in ascertaining the clinical value of miRs and in understanding how they might contribute to pathogenesis is predicated upon resolving current methodological challenges in studies. These include differences in diagnostic criteria, cohort characteristics, sampling technique, RNA isolation and platform-dependent variation in miR profiling.

Conclusion

Reviewing studies of PE-associated miRs has revealed their potential as informants of underlying target genes and pathways relating to PE pathogenesis. However, the incongruity in results across current studies hampers their capacity to be useful biomarkers of the condition.

miRNAs as common regulators of the transforming growth factor (TGF)-β pathway in the preeclamptic placenta and cadmium-treated trophoblasts: Links between the environment, the epigenome and preeclampsia

Preeclampsia (PE) is a pregnancy disorder characterized by high blood pressure and proteinuria that can cause adverse health effects in both mother and fetus. There is no current cure for PE other than delivery of the fetus/placenta. While the etiology is unknown, poor placentation due to aberrant signaling of growth and angiogenic factors has been postulated as a causal factor of PE. In addition, environmental contaminants, such as the metal cadmium (Cd), have been linked to placental toxicity and increased risk of developing PE. Here, we use a translational study design to investigate genomic and epigenomic alterations in both placentas and placental trophoblasts, focused on the angiogenesis-associated transforming growth factor-beta (TGF-β) pathway. Genes within the TGF-β pathway displayed increased expression in both the preeclamptic placenta and Cd-treated trophoblasts. In addition, miRNAs that target the TGF-β pathway were also significantly altered within the preeclamptic placenta and Cd-treated trophoblasts. Integrative analysis resulted in the identification of a subset of Cd-responsive miRNAs, including miR-26a and miR-155, common to preeclamptic placentas and Cd-treated trophoblasts. These miRNAs have previously been linked to PE and are predicted to regulate members of the TGF-β pathway. Results from this study provide future targets for PE treatment.

MicroRNA-128a-induced apoptosis in HTR-8/SVneo trophoblast cells contributes to pre-eclampsia

INTRODUCTION

Pre-eclampsia (PE) can endanger the survival of the mother and fetus. Currently, the pathogenesis of PE is not completely understood and no fundamental therapeutics are available. The present study was performed to determine the function of miR-128a in HTR-8/SVneo trophoblast cells and to ascertain its underlying role in the pathogenesis of PE.

METHODS

We investigated the function of miR-128a in HTR-8/SVneo cells by overexpressing. We analyzed the apoptosis of HTR-8/SVneo cells by performing apoptosis assays and measured the loss of mitochondrial membrane potential (Δym), the generation of reactive oxygen species (ROS) and caspase activity. In addition, miR-128a target genes were predicted.

RESULTS

Using computer-based programs, we identified Bax as a direct target of miR-128a. In the apoptosis assays of HTR-8/SVneo cells, miR-128a decreased the Δψm, depleted ATP levels and increased ROS generation, cytochrome c release as well as caspase activation. Further studies showed that miR-128a induced the apoptosis of HTR-8/SVneo cells by down-regulating Bax through the mitochondrial apoptosis pathway.

CONCLUSIONS

miR-128a is an up-regulated miRNA in patient with PE. Our study demonstrated that the miR-128a-induced apoptosis of HTR-8/SVneo cells may contribute to PE and miR-128a may be a novel potential therapeutic target for PE.

The aberrantly expressed miR-193b-3p contributes to preeclampsia through regulating transforming growth factor-β signaling

Preeclampsia (PE) is a leading cause of maternal mortality worldwide. Several studies have detected some differentially expressed microRNAs in the preeclamptic placenta, but few of the identified microRNAs demonstrated consistent findings among different research studies. In this study, high-throughput microRNA sequencing (HTS) of 9 preeclamptic and 9 normal placentas was performed. Seventeen microRNAs were identified to be up-regulated, and 8 down-regulated in preeclamptic placentas. Eight differentially expressed microRNAs except one identified in our study were determined to be consistent with at least one previous study, while sixteen were newly found. We performed qRT-PCR with independent 22 preeclamptic placentas and 20 control placentas to verify the differentially expressed microRNAs, and ten microRNAs were validated. The predicted target genes of the aberrantly expressed miR-193b-3p were enriched in the following gene ontology categories: cell motility and migration, cell proliferation and angiogenesis. We also found that miR-193b-3p significantly decreased the migration and invasion of trophoblast (HTR-8/SVneo) cells and that miR-193b-3p could regulate trophoblasts migration and invasion through binding onto the 3′UTR target site of TGF-β2. In conclusion, we identified a list of differentially expressed microRNAs in PE placentas by HTS and provided preliminary evidence for the role of miR-193b-3p in the pathogenesis of preeclampsia.

Quantification of preeclampsia-related microRNAs in maternal serum

To identify the specific serum preeclampsia (PE)-related biomarkers, 10 microRNAs (miRNAs) were selected based on their reported aberrant (4 upregulated and 6 downregulated) expression in PE placenta. A total of 1,035 pregnant patients were enrolled. Finally, 32 pregnancies with PE and 32 healthy pregnancies were incorporated in the study. The expression of these 10 miRNAs in the different trimesters was determined by SYBR-Green reverse transcription-quantitative polymerase chain reaction. Compared with that in the healthy controls, the expression levels of miR-152, miR-183 and miR-210 in PE serum were higher in the second and third trimester, whereas the expression of miR-182 was only higher in the third trimester. The expression levels of 6 miRNAs (miR-1, miR-328, miR-363, miR-377, miR-500 and miR-584) that were downregulated in PE placenta showed no significant differences between pregnancies complicated by PE and healthy pregnancies throughout the 3 trimesters. Areas under the receiver operating characteristic [standard error (SE)] during the 20-24th gestational week for predicting PE were miR-152: 0.94 (SE, 0.026), miR-183: 0.97 (SE, 0.031) and miR-210: 0.93 (SE, 0.018). In conclusion, the expression levels of serum miR-152, miR-183 and miR-210 were elevated since the second trimester in pregnancies complicated with PE, indicating their potentials as serum biomarkers for forecasting PE.

Cardiovascular and Cerebrovascular Disease Associated microRNAs Are Dysregulated in Placental Tissues Affected with Gestational Hypertension, Preeclampsia and Intrauterine Growth Restriction

Aims

To demonstrate that pregnancy-related complications are associated with alterations in cardiovascular and cerebrovascular microRNA expression. Gene expression of 32 microRNAs (miR-1-3p, miR-16-5p, miR-17-5p, miR-20a-5p, miR-20b-5p, miR-21-5p, miR-23a-3p, miR-24-3p, miR-26a-5p, miR-29a-3p, miR-33a-5p, miR-92a-3p, miR-100-5p, miR-103a-3p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-130b-3p, miR-133a-3p, miR-143-3p, miR-145-5p, miR-146a-5p, miR-155-5p, miR-181a-5p, miR-195-5p, miR-199a-5p, miR-208a-3p, miR-210-3p, miR-221-3p, miR-342-3p, miR-499a-5p, and miR-574-3p) was assessed in placental tissues, compared between groups (35 gestational hypertension, 80 preeclampsia, 35 intrauterine growth restriction and 20 normal pregnancies) and correlated with the severity of the disease with respect to clinical signs, delivery date, and Doppler ultrasound parameters. Initially, selection and validation of endogenous controls for microRNA expression studies in placental tissues affected by pregnancy-related complications have been carried out.

Results

The expression profile of microRNAs was different between pregnancy-related complications and controls. The up-regulation of miR-499a-5p was a common phenomenon shared between gestational hypertension, preeclampsia, and intrauterine growth restriction. Preeclamptic pregnancies delivering after 34 weeks of gestation and IUGR with abnormal values of flow rate in the umbilical artery demonstrated up-regulation of miR-1-3b. Preeclampsia and IUGR requiring termination of gestation before 34 weeks of gestation were associated with down-regulation of miR-26a-5p, miR-103a-3p and miR-145-5p. On the other hand, some of microRNAs (miR-16-5p, miR-100-5p, miR-122-5p, miR-125b-5p, miR-126-3p, miR-143-3p, miR-195-5p, miR-199a-5p, miR-221-3p, miR-342-3p, and miR-574-3p) were only down-regulated or showed a trend to down-regulation just in intrauterine growth restriction pregnancies requiring the delivery before 34 weeks of gestation.

Conclusion

Epigenetic changes induced by pregnancy-related complications in placental tissue may cause later onset of cardiovascular and cerebrovascular diseases in offspring.

miRNAs in pregnancy-related complications

MicroRNAs (miRNAs) constitute a highly conserved class of small non-coding RNAs, involved in post-transcriptional regulation processes by modifying the expression of specific mRNAs. During placental development, cell differentiation, adhesion, migration, apoptosis and angiogenesis are regulated by specific miRNAs and aberrant expression has been associated with the pathogenesis of pregnancy-related complications. Recent studies focusing on placental and maternal peripheral blood miRNA profiling showed different expression between normal and complicated pregnancies, providing valuable information about the pathophysiological role of miRNAs and identifying potential biomarkers for monitoring pregnancy complications. This review summarizes the current knowledge in the field and presents the possible use of miRNAs as biomarkers for early detection and monitoring of these complications.

Gestational tissue transcriptomics in term and preterm human pregnancies: a systematic review and meta-analysis

BACKGROUND

Preterm birth (PTB), or birth before 37 weeks of gestation, is the leading cause of newborn death worldwide. PTB is a critical area of scientific study not only due to its worldwide toll on human lives and economies, but also due to our limited understanding of its pathogenesis and, therefore, its prevention. This systematic review and meta-analysis synthesizes the landscape of PTB transcriptomics research to further our understanding of the genes and pathways involved in PTB subtypes.

METHODS

We evaluated published genome-wide pregnancy studies across gestational tissues and pathologies, including those that focus on PTB, by performing a targeted PubMed MeSH search and systematically reviewing all relevant studies.

RESULTS

Our search yielded 2,361 studies on gestational tissues including placenta, decidua, myometrium, maternal blood, cervix, fetal membranes (chorion and amnion), umbilical cord, fetal blood, and basal plate. Selecting only those original research studies that measured transcription on a genome-wide scale and reported lists of expressed genetic elements identified 93 gene expression, 21 microRNA, and 20 methylation studies. Although 30 % of all PTB cases are due to medical indications, 76 % of the preterm studies focused on them. In contrast, only 18 % of the preterm studies focused on spontaneous onset of labor, which is responsible for 45 % of all PTB cases. Furthermore, only 23 of the 10,993 unique genetic elements reported to be transcriptionally active were recovered 10 or more times in these 134 studies. Meta-analysis of the 93 gene expression studies across 9 distinct gestational tissues and 29 clinical phenotypes showed limited overlap of genes identified as differentially expressed across studies.

CONCLUSIONS

Overall, profiles of differentially expressed genes were highly heterogeneous both between as well as within clinical subtypes and tissues as well as between studies of the same clinical subtype and tissue. These results suggest that large gaps still exist in the transcriptomic study of specific clinical subtypes as well in the generation of the transcriptional profile of well-studied clinical subtypes; understanding the complex landscape of prematurity will require large-scale, systematic genome-wide analyses of human gestational tissues on both understudied and well-studied subtypes alike.

Expression profile of C19MC microRNAs in placental tissue in pregnancy-related complications

To demonstrate that pregnancy-related complications are associated with alterations in placental microRNA expression. Gene expression of 15 C19MC microRNAs (miR-512-5p, miR-515-5p, miR-516-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-519e-5p, miR-520a-5p, miR-520h, miR-524-5p, miR-525, miR-526a, and miR-526b) was assessed in placental tissues, compared between groups (21 gestational hypertension [GH], 63 preeclampsia, 36 fetal growth restriction [FGR], and 42 normal pregnancies), and correlated with the severity of the disease with respect to clinical signs, delivery date, and Doppler ultrasound parameters. The expression profile of microRNAs was different between pregnancy-related complications and controls. The downregulation of 4 of 15 (miR-517-5p, miR-519d, miR-520a-5p, and miR-525), 6 of 15 (miR-517-5p, miR-518f-5p, miR-519a, miR-519d, miR-520a-5p, and miR-525), and 11 of 15 (miR-515-5p, miR-517-5p, miR-518b, miR-518f-5p, miR-519a, miR-519d, miR-520a-5p, miR-520h, miR-524-5p, miR-525, and miR-526a) microRNAs was associated with GH, FGR, and preeclampsia, respectively. Sudden onset of severe preeclampsia requiring immediate termination of gestation and mild forms of preeclampsia (persisting for several weeks) were associated with similar microRNA expression profile (downregulation of miR-517-5p, miR-520a-5p, miR-524-5p, and miR-525). In addition, miR-519a was found to be associated with severe preeclampsia. The longer the pregnancy-related disorder lasted, the more extensive was the downregulation of microRNAs (miR-515-5p, miR-518b, miR-518f-5p, miR-519d, and miR-520h). The downregulation of some C19MC microRNAs is a common phenomenon shared between GH, preeclampsia, and FGR. On the other hand, some of the C19MC microRNAs are only downregulated just in preeclampsia.

Differential expression of microRNAs in decidua-derived mesenchymal stem cells from patients with pre-eclampsia

BACKGROUND

Mesenchymal stem cells (MSCs) at maternal-fetal interface are considered to play an important role in the pathogenesis of pre-eclampsia (PE). microRNAs (miRNAs) also have an important influence on differentiation, maturation, and functions of MSCs. Our aim in this study was to determine the differential expression of miRNAs in decidua-derived MSCs (dMSCs) from severe PE and normal pregnancies.

RESULTS

miRNA expression profiles in dMSCs from five patients with severe PE and five healthy pregnant women were screened using microarray. Then, bioinformatic analysis of the microarray results was performed. Out of 179 differentially expressed miRNAs, 49 miRNAs had significant (p < 0.05) differential expression of ≥ 2.0-fold changes, including 21 up-regulated and 28 down-regulated. miRNA-Gene-network and miRNA-Gene ontology (GO) -network analyses were performed. Overall, 21 up-regulated and 15 down-regulated miRNAs showed high degrees in these analyses. Moreover, the significantly enriched signaling pathways and GOs were identified. The analyses revealed that pathways associated with cell proliferation, angiogenesis, and immune functions were highly regulated by the differentially expressed miRNAs, including Wnt signaling pathway, mitogen-activated protein kinase signaling pathway, transforming growth factor beta signaling pathway, T-cell receptor signaling pathway, and B cell receptor signaling pathway. Four miRNA predicted target genes, vascular endothelial growth factor A (VEGFA), indoleamine 2,3-dioxygenase, suppression of cytokine signaling 3, and serine/threonine protein phosphatase 2A 55 kDa regulatory subunit B α isoform (PPP2R2A) were all decreased in dMSCs from patients with PE. Furthermore, the physiological roles of miR-16 and miR-136 in the down-regulation of VEGFA and PPP2R2A, respectively, were confirmed through reporter assays.

CONCLUSIONS

These findings suggest that miRNAs in dMSCs may be important regulatory molecules in the development of PE.

Epigenetics, the missing link in hypertension

Epigenetics refers to functional alterations in gene expression or phenotype without any change of the underlying DNA sequence. It is the study of the potential of a cell or organism to express different traits through functional regulation of its gene transcription. Though it is met as a necessary process in biology, epigenetics may often play a crucial part in the development of specific pathologic conditions, including cardiovascular diseases and hypertension.

MicroRNAs, immune cells and pregnancy

MicroRNAs (miRNAs) are a recently discovered class of non-coding RNAs that are expressed in many cell types, where they regulate the expression of complementary RNAs, thus modulating the stability and translation of mRNAs. miRNAs are predicted to regulate the expression of ∼50% of all protein coding genes in mammals. Therefore, they participate in virtually all cellular processes investigated so far. Altered miRNAs expressions are associated with both physiological (pregnancy) and pathological processes (cancer). As the dynamic maternal-fetal interface plays a critical role in the maintenance of successful pregnancy, it is not surprising that the miRNAs that are unique to reproductive tissues are abundantly expressed. Research in this field has demonstrated the presence and dysregulation of a distinct set of pregnancy-associated miRNAs; however, most studies have centered on localizing various miRNAs in reproductive microdomains associated with normal or complicated pregnancies. Although several independent miRNA regulatory mechanisms associated with endometrial receptivity, immune cells, angiogenesis and placental development have been studied, miRNA-mediated regulation of pregnancy remains poorly understood. This review provides a summary of the current data on miRNA regulation as well as functional profiles of miRNAs that are found in the uterus, in immune cells associated with maternal tolerance to the fetus, and those involved in angiogenesis and placental development.

MicroRNAs: are they the missing link between hypoxia and pre-eclampsia?

Pre-eclampsia is a multisystem disorder that occurs in the second half of pregnancy affecting 5% of pregnancies. It remains the leading cause of maternal and perinatal mortality and morbidity worldwide. Impaired placental implantation, hypoxia, endothelial dysfunction and systemic inflammation are thought to have a role in the pathogenesis of pre-eclampsia. MicroRNAs (miRNAs) are short non-coding RNAs. They are important regulators of gene expression and have been found to affect cell development, proliferation, differentiation and function. Specific patterns of miRNAs have been detected in the placenta and there is altered miRNA expression in the placenta of patients with pre-eclampsia to but their role in the pathogenesis remains unclear. Furthermore, deregulated miRNAs have also been reported in human villous trophoblasts during hypoxic stress. One of the more consistently elevated miRNAs by hypoxia and in the placenta of patients with pre-eclampsia is miR-210. Whether such miRNAs are bystander markers of hypoxia, or are directly involved in the pathogenesis of pre-eclampsia, needs to be clarified. There is potential for miRNAs to be used as predictors, markers or therapy in pre-eclampsia. This review provides current knowledge about miRNAs, particularly hypoxia-related miRNAs and the interaction of hypoxia, miRNAs and placenta in pre-eclampsia.

miRNA expression profiles determined in maternal sera of patients with HELLP syndrome

OBJECTIVE

Syndrome of hemolysis, elevated liver enzymes and low platelets (HELLP) represents a distinct subgroup of severe preeclampsia. The aim of our study was to identify differentially expressed miRNAs in sera of patients with HELLP syndrome in comparison to unaffected controls.

STUDY DESIGN

Blood samples were obtained from patients with manifest HELLP syndrome and matched unaffected controls. The expression of 754 mature miRNAs was assessed using the TaqMan Array format (n = 12). Results of seven differentially expressed miRNAs were further validated by single quantitative real-time polymerase chain reaction (qPCR) assays.

RESULTS

Serum miRNA analysis allowed detection of maternal and fetal miRNAs. Distinct miRNA expressions were confirmed for miR-122, miR-758 and miR-133a represented by a median up-regulation ≥ two-fold in the HELLP group. The liver specific miR-122 was 11.5-fold increased with an area under curve (AUC) of 0.82 in the receiver operating characteristic (ROC) analysis. Cluster analyses of our data uncovered subgroups of HELLP patients were associated with clinical subtypes and differences in organ manifestation.

CONCLUSION

In our proof of principle study, we demonstrated that patients with HELLP syndrome showed alterations of serum miRNA expression patterns. Data analysis goes along with the hypothesis that HELLP syndrome is regarded to be a heterogeneous disease.

MicroRNA analysis in placentas from patients with preeclampsia: comparison of new and published results

OBJECTIVE

The aim was to identify differences in microRNA expression between patients with and without preeclampsia.

METHODS

Microarray-based study was carried out with placental samples.

RESULTS

Comparison of eight previous studies with the current study revealed a total of 138 microRNAs; only 20/138 (14%), however, were seen in more than one study and the results agreed in the direction of change. Bioinformatic analysis of these 20 microRNAs identified a wide range of biological functions including apoptosis and cell movement for their mRNA targets.

CONCLUSION

The associations between miRNA expression and preeclampsia suggest a potential role for microRNAs in preeclampsia pathobiology.

MicroRNA expression profiles in placenta with severe preeclampsia using a PNA-based microarray

INTRODUCTION

Preeclampsia (PE) is a leading cause of maternal and neonatal mortality and morbidity worldwide. However, the pathophysiology of this disease is not yet fully understood. MiRNA plays an important role in post-transcriptional gene regulation. Recent studies have suggested that dysregulation of miRNAs in placental tissue is involved in the pathogenesis of PE. Therefore, we investigated miRNA profiles in PE placenta to understand the miRNA function in PE pathogenesis.

METHODS

MiRNA profiling was performed in 20 formalin-fixed and paraffin-embedded samples (10 placentas from severe PE and 10 from a control group). We used a hybridization-based microarray with a PNA-probe comprised of 158 miRNAs.

RESULTS

Thirteen miRNAs (miR-92b, miR-197, miR-342-3p, miR-296-5p, miR-26b, miR-25, miR-296-3p, miR-26a, miR-198, miR-202, miR-191, miR-95, and miR-204) were significantly overexpressed and two miRNAs (miR-21 and miR-223) were underexpressed in PE compared with the control group. Among 15 differentially expressed miRNAs, miR-26b, miR-296-5p, and miR-223 were found to be consistent with results from previous studies. We identified 893 genes that were predicted by at least three of four computational algorithms. Target genes participated in several signaling pathways, adherens junction, focal adhesion, and regulation of the actin cytoskeleton.

CONCLUSIONS

Several miRNAs are found to be dysregulated in placentas of PE patients and they seem to be closely associated with the early pathogenesis of PE. Further study is necessary to develop tools for early detection and management.