Identifying miRNA regulatory mechanisms in preeclampsia by systems biology approaches

The Role of microRNAs in Inflammation

Inflammation is a biological response of the immune system to various insults, such as pathogens, toxic compounds, damaged cells, and radiation. The complex network of pro- and anti-inflammatory factors and their direction towards inflammation often leads to the development and progression of various inflammation-associated diseases. The role of small non-coding RNAs (small ncRNAs) in inflammation has gained much attention in the past two decades for their regulation of inflammatory gene expression at multiple levels and their potential to serve as biomarkers and therapeutic targets in various diseases. One group of small ncRNAs, microRNAs (miRNAs), has become a key regulator in various inflammatory disease conditions. Their fine-tuning of target gene regulation often turns out to be an important factor in controlling aberrant inflammatory reactions in the system. This review summarizes the biogenesis of miRNA and the mechanisms of miRNA-mediated gene regulation. The review also briefly discusses various pro- and anti-inflammatory miRNAs, their targets and functions, and provides a detailed discussion on the role of miR-10a in inflammation.

miR-24-3p regulation of retinol binding protein 4 in trophoblast biofunction and preeclampsia

Preeclampsia (PE) is a pregnancy-related disease and is the leading cause of overall maternal mortality and morbidity. Our previous studies have shown that the serum and placental levels of retinol-binding protein 4 (RBP4) in PE are reduced. Our previous bioinformatics analysis predicted that RBP4 is a target of the microRNA miRNA-24-3p. In this study, our database analysis also indicated that RBP4 is a miR-24-3p target. Compared with that of the normal placenta, the expression level of RBP4 in human PE placenta was significantly reduced, and miR-24-3p was highly expressed. In HTR-8/SVneo cells, transfection of exogenous miR-24-3p reduced RBP4 expression. A dual-luciferase reporter assay validated RBP4 as a direct target of miR-24-3p, indicating that it directly binds to the 3'-untranslated region of RBP4. This binding was reversed by a mutation in the microRNA-binding site. Transwell invasion experiments and CCK8 assay showed that inhibitory effect of miR-24-3p reduced RBP4 mediated HTR-8/SVneo cell invasion and proliferation. These data provide a new overarching perspective on the physiological role played by miR-24-3p in regulating RBP4 during trophoblast dysfunction and PE development.

Mast cell-derived exosomal miR-181a-5p modulated trophoblast cell viability, migration, and invasion via YY1/MMP-9 axis

Background

Mast cells regulate the process of preeclampsia (PE). Since we previously identified mast cells specifically expressing miR‐181a‐5p in the placenta of PE patients, it is plausible to examine the effect and mechanism of mast cell‐derived exosomal miR‐181a‐5p on trophoblast cells.

Methods

The miR‐181a‐5p and YY1 levels were determined by quantitative real‐time reverse transcription‐polymerase chain reaction. Exosomes were identified by transmission electron microscopy, Western blot, and PKH‐26 labeling. Mast cells or trophoblast cell malignant phenotype were detected using 3‐(4,5‐dimethyl‐2‐thiazolyl)‐2,5‐diphenyl‐2‐H‐tetrazolium bromide, wound healing, and Transwell assays. Quantification of YY1 and metastasis‐related proteins was performed using Western blot. TargetScan, JASPAR, dual‐luciferase reporter genes, and chromatin immunoprecipitation were exploited to verify the relationship between miR‐181a‐5p, YY1, and MMP‐9.

Results

MiR‐181a‐5p was overexpressed in mast cells of PE patients. Overexpressed miR‐181a‐5p restrained mast cell viability. Mast cell exosomes were successfully isolated, containing high expressions of CD63 and HSP70 and low expression of Calnexin and could be transported to the cytoplasm of trophoblast cells. Mast cell exosomes attenuated the viability, migration, and invasion of HTR‐8/SVneo cells, inhibited YY1, N‐cadherin, Vimentin, and MMP‐9 protein expressions, and promoted E‐cadherin protein expression. The effect of exosomes was enhanced by miR‐181a‐5p mimic but was reversed by miR‐181a‐5p inhibitor. MiR‐181a‐5p targeted YY1 which bound to the MMP‐9 promoter. Overexpressed YY1 in HTR‐8/SVneo cells accelerated the malignant phenotype of the cells and reversed the regulatory effects of exosomal miR‐181a‐5p.

Conclusion

Mast cell‐derived exosomal miR‐181a‐5p modulates HTR‐8/SVneo cell viability, migration, and invasion via YY1/MMP‐9.

Upregulation of circRNA hsa_circ_0008726 in Pre-eclampsia Inhibits Trophoblast Migration, Invasion, and EMT by Regulating miR-345-3p/RYBP Axis

Accumulating evidence shows that impaired spiral artery remodeling, placental dysfunction, and insufficient trophoblast infiltration contribute to the etiology and pathogenesis of pre-eclampsia (PE). circRNAs are a class of endogenous non-coding RNAs implicated in the pathogenesis of many diseases, including PE. This study aims to investigate the role of circRNA hsa_circ_0008726 in regulating the migration and invasion of extravillous trophoblast cells. RNase R assay was performed to confirm that circ_0008726 was a circular transcript. The expression of circ_0008726, RYBP, and miR-345-3p was examined by qRT-PCR. The functional interaction between miR-345-3p and circ_0008726 or RYBP was confirmed using dual-luciferase reporter assay and RNA immunoprecipitation (RIP). Cell migration and invasion ability was analyzed by Transwell assays. Western blot was used for the quantification of RYBP protein level. Circ_0008726 expression was significantly increased in PE placenta tissues as compared with normal placenta tissues. Circ_0008726 was resistant to RNase R digestion and was predominately located in the cytoplasm of HTR-8/SVneo cells. Silencing circ_0008726 promoted cell migration and EMT (epithelial-mesenchymal transition), while circ_0008726 overexpression suppressed these processes. Mechanistically, circ_0008726 sponged miR-345-3p to negatively regulate its expression, and miR-345-3p negatively modulated the expression of RYBP. In PE samples, the expression level of circ_0008726 was negatively correlated with miR-345-3p level, but was positively correlated with RYBP expression. Transfection of miR-345-3p mimic or RYBP knockdown counteracted the effects of circ_0008726 overexpression on cell migration and EMT. Our data demonstrate the upregulation of circ_0008726 in PE placenta, which inhibits the migration, invasion, and EMT of HTR-8/SVneo cells by targeting miR-345-3p/RYBP axis. These data suggest that circ_0008726 could be a potential biomarker and therapeutic target for PE.

Epigenetic processes during preeclampsia and effects on fetal development and chronic health

Preeclampsia (PE), the leading cause of maternal and fetal morbidity and mortality, is associated with poor fetal growth, intrauterine growth restriction (IUGR) and low birth weight (LBW). Offspring of women who had PE are at increased risk for cardiovascular (CV) disease later in life. However, the exact etiology of PE is unknown. Moreover, there are no effective interventions to treat PE or alleviate IUGR and the developmental origins of chronic disease in the offspring. The placenta is critical to fetal growth and development. Epigenetic regulatory processes such as histone modifications, microRNAs and DNA methylation play an important role in placental development including contributions to the regulation of trophoblast invasion and remodeling of the spiral arteries. Epigenetic processes that lead to changes in placental gene expression in PE mediate downstream effects that contribute to the development of placenta dysfunction, a critical mediator in the onset of PE, impaired fetal growth and IUGR. Therefore, this review will focus on epigenetic processes that contribute to the pathogenesis of PE and IUGR. Understanding the epigenetic mechanisms that contribute to normal placental development and the initiating events in PE may lead to novel therapeutic targets in PE that improve fetal growth and mitigate increased CV risk in the offspring.

Circular RNA hsa_circ_0026552 inhibits the proliferation, migration and invasion of trophoblast cells via the miR‑331‑3p/TGF‑βR1 axis in pre‑eclampsia

Globally, pre-eclampsia (PE) is a gestational disorder that causes increased morbidity of the fetus and mortality induced by pregnancy. Despite various studies, the understanding of the causes or mechanism of the development of PE remains elusive. Thus, the present study aimed to investigate the role of circular (circ)RNA hsa_circ_0026552 (hsa_circ_0026552) in the development of PE and its mechanism of regulation. hsa_circ_0026552 differential expression in PE tissue data and clinical samples were analyzed and it was observed that hsa_circ_0026552 is highly upregulated in PE samples. Furthermore, miR-331-3p was detected as an hsa_circ_0026552 target miRNA and TGF-βR1 gene as a target of miR-331-3p. These results were confirmed using various assays, including dual-luciferase reporter, reverse transcription-quantitative PCR and RNA pull-down assay. It was observed that miR-331-3p expression was negatively correlated to hsa_circ_0026552 relative expression, while TGF-βR1 expression was positively correlated to hsa_circ_0026552 expression evaluated by Pearson's correlation test. The functional experiments, including Cell Counting Kit-8, colony formation and Transwell assay, showed that silencing hsa_circ_0026552 could significantly strengthen the proliferation, migration and invasion of the trophoblastic HTR-8/SVneo cells, but the subsequent overexpression of hsa_circ_0026552 reversed this. Mechanistically, it was concluded that hsa_circ_0026552 acts as a miR-331-3p sponge to upregulate TGF-βR1 expression in trophoblasts and is involved significantly in PE development and progression in pregnant women. The circRNA hsa_circ_0026552 could be a novel therapeutic target and prognostic biomarker for PE.

Insight into the Key Points of Preeclampsia Pathophysiology: Uterine Artery Remodeling and the Role of MicroRNAs

Preeclampsia affects about 3-8% of all pregnancies. It represents a complex and multifaceted syndrome with at least several potential pathways leading to the development of disease. The main dogma in preeclampsia is the two-stage model of disease. Stage 1 (placental stage) takes place in early pregnancy and is thought to be impaired placentation due to inadequate trophoblastic invasion of the maternal spiral arteries that leads to reduced placental perfusion and release of numerous biological factors causing endothelial damage and development of acute maternal syndrome with systemic multiorgan failure (stage 2-the onset of maternal clinical symptoms, maternal stage). Recently, in the light of the vast body of evidence, two-stage model of preeclampsia has been updated with a few novel pathways leading to clinical manifestation in the second part of pregnancy. This paper reviews current state of knowledge about pathophysiology of preeclampsia and places particular focus on the recent advances in understanding of uterine artery remodeling alterations, as well as the role of microRNAs in preeclampsia.

miR-483 is downregulated in pre-eclampsia via targeting insulin-like growth factor 1 (IGF1) and regulates the PI3K/Akt/mTOR pathway of endothelial progenitor cells

AIM

Pre-eclampsia is a serious pregnancy-specific disease with an incidence of 9.4%. MicroRNAs play a key role in regulating factors in pre-eclampsia, but related research is still limited. This study aims to reveal the role and potential mechanisms of miR-483 in pre-eclampsia.

METHODS

miR-483 was detected in venous blood, umbilical cord blood and placental tissue of pre-eclampsia patients by Real-time Quantitative polymerase chain reaction (qRT-PCR). Insulin-like growth factor (IGF1) and miR-483 were detected by qRT-PCR and western blot in endothelial progenitor cells isolated from fetal umbilical cord blood. miR-483 was overexpressed and inhibited to detect changes of IGF1 and PI3K/Akt/mTOR pathway in endothelial progenitor cells by qRT-PCR and western blot.

RESULTS

miR-483 was downregulated in venous blood, umbilical cord blood and placental tissue of pre-eclampsia patients. In endothelial progenitor cells, overexpression of miR-483 inhibited the expression of IGF1, and inhibition of miR-483 promoted the expression of IGF1. miR-483 regulates the expression of PI3K, Akt, and mTOR in endothelial progenitor cells.

CONCLUSION

miR-483 is downregulated in pre-eclampsia and regulates endothelial progenitor cells by targeting IGF1. miR-483 is a potential alternative for diagnosing and treating pre-eclampsia.

Circular RNA circ_0111277 attenuates human trophoblast cell invasion and migration by regulating miR-494/HTRA1/Notch-1 signal pathway in pre-eclampsia

Mounting evidence has revealed that impaired spiral artery remodeling, placental dysfunction, and inadequate trophoblast invasion are closely correlated with the etiology and pathogenesis of pre-eclampsia (PE). Moreover, defective trophoblast invasion may trigger poor maternal-fetal circulation and placental hypoxia, leading to PE. However, the detailed molecular pathology of PE remains unclear. Although circRNAs, as a new type of stable and abundant endogenous noncoding RNA, have been proven to be essential to the pathogenesis of various diseases, their role in PE requires further verification. In this context, it is necessary to unveil the roles of circRNAs in regulating the migration and invasion of extravillous trophoblasts. In this study, using quantitative real-time PCR, we confirmed that hsa_circ_0111277 was upregulated in PE placentas relative to the level in normal pregnancy placentas. In addition, positive correlations between hsa_circ_0111277 expression and PE-related factors (proteinuria level at 24 h and placental weight) were identified by Pearson's analysis based on the clinical data of 25 PE patients. Moreover, fluorescence in situ hybridization analysis illustrated that circ_0111277 was preferentially localized within the cytoplasm. Mechanistically, circ_0111277 sponged hsa-miR-494-3p in trophoblast cells to attenuate the latter's repression by regulating HTRA1/Notch-1 expression. In conclusion, trophoblast cell migration and invasion were shown to be promoted and modulated by the hsa_circ_0111277/miR-494-3p/HTRA1/Notch-1 axis, which provides useful insight for exploring a new therapeutic approach for PE.

Long non-coding RNA HOTAIR modulates the progression of preeclampsia through inhibiting miR-106 in an EZH2-dependent manner

AIMS

Preeclampsia (PE) accounts for the foremost cause of maternal and fetal mortality worldwide, whereas, there are no effective treatments for the disease yet. Long non-coding RNAs (lncRNAs) play critical roles in various human disorders, including PE. Here, we identified an up-regulated lncRNA HOTAIR, and explored its underlying mechanisms in PE.

MAIN METHODS

qRT-PCR analysis was used to examine HOTAIR expression in PE tissues and cell lines. Trophoblast proliferation was examined by colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assays. Trophoblast migration and invasion was determined by transwell and wound healing assays. Bioinformatics analysis was performed to verify the regulation HOTAIR on miRNAs. The interaction between HOTAIR and EZH2 was detected using RNA immunoprecipitation assay (RIP). Chromatin immunoprecipitation (CHIP) assay was also performed to verify that the negative regulation of HOTAIR on miR-106a was dependent on the epigenetic repressor EZH2.

KEY FINDINGS

HOTAIR was up-regulated in PE placenta tissues, which repressed the proliferation, migration and invasion of trophoblast cells. HOTAIR significantly repressed miR-106a expression and the reduced miR-106a level was also observed in placentas from PE patients. Additionally, miR-106a mimic enhanced the migration and invasion of trophoblast cells. Further mechanistic analyses implied that the action of HOTAIR is moderately attributable to its repression of miR-106a via association with EZH2.

SIGNIFICANCE

High level of HOTAIR repressed the proliferation, migration and invasion of trophoblast cells through targeting miR-106 in an EZH2-dependent manner, which may provide new insights into the roles of HOTAIR and miR-106a as potential regulators in PE.

A review of omics approaches to study preeclampsia

Preeclampsia is a medical condition affecting 5-10% of pregnancies. It has serious effects on the health of the pregnant mother and developing fetus. While possible causes of preeclampsia are speculated, there is no consensus on its etiology. The advancement of big data and high-throughput technologies enables to study preeclampsia at the new and systematic level. In this review, we first highlight the recent progress made in the field of preeclampsia research using various omics technology platforms, including epigenetics, genome-wide association studies (GWAS), transcriptomics, proteomics and metabolomics. Next, we integrate the results in individual omic level studies, and show that despite the lack of coherent biomarkers in all omics studies, inhibin is a potential preeclamptic biomarker supported by GWAS, transcriptomics and DNA methylation evidence. Using network analysis on the biomarkers of all the literature reviewed here, we identify four striking sub-networks with clear biological functions supported by previous molecular-biology and clinical observations. In summary, omics integration approach offers the promise to understand molecular mechanisms in preeclampsia.

MicroRNA-576-5p enhances the invasion ability of trophoblast cells in preeclampsia by targeting TFAP2A

Background

Preeclampsia (PE) is a common pregnancy‐related syndrome characterized by hypertension and proteinuria, and a major cause of maternal mortality. Therefore, there is an urgent need to identify early biomarkers of PE. The aim of the present study was to identify the functions of miR‐576‐5p in PE.

Methods

Effects of miR‐576‐5p and transcription factor AP‐2α (TFAP2A) on invasion of human trophoblast HTR8/SVneo cells were investigated. Real‐time quantitative polymerase chain reaction (RT‐qPCR) and western blotting were used to assess the expression of miR‐576‐5p, TFAP2A, E‐cad, and Vimentin in PE tissues and cells. Additionally, immunofluorescence was used to detect the expression of TFAP2A in PE trophoblastic tissue. Subsequently, constructed miR‐576‐5p mimics, miR‐576‐5p inhibitor, and siRNA‐TFAP2A plasmids were transfected into HTR8/SVneo cells for further experiments, including a CCK‐8 assay for cell proliferation, Transwell assay for cell invasion and the luciferase reporter gene system was employed for target verification.

Results

A lower expression of miR‐576‐5p and a higher expression of TFAP2A were identified in PE rats. E‐cadherin was highly expressed while Vimentin was downregulated. Further statistical analysis indicated that cell proliferation of HTR8/SVneo cells decreased in the miR‐576‐5p inhibitor group and increased in the miR‐576‐5p mimics and siRNA‐TFAP2A groups. miR‐576‐5p inhibitor suppressed cell invasion, and miR‐576‐5p mimics and siRNA‐TFAP2A improved cell invasion. The analysis of luciferase reporter demonstrated a decreased luciferase activity in miR‐576‐5p mimics group compared with control group, which indicates that TFAP2A may be a target of miR‐576‐5p. Interference of TFAP2A could downregulate E‐cadherin and upregulate Vimentin expression.

Conclusion

Overexpression of miR‐576‐5p and knockdown of TFAP2A may elevate cell proliferation and invasion of human trophoblast cells in vitro. Therefore, miR‐576‐5p may be used as a notable biomarker for the diagnosis, prevention, and treatment of PE. miR‐576‐5p targeting TFAP2A deserve further investigation in order to explore their potential role in PE.

Circular RNAs in hypertension: challenges and clinical promise

Hypertension (HT), or high blood pressure (BP), is a chronic disease that is common among populations worldwide. The occurrence of HT is one of the leading causes of cardiovascular morbidity and mortality in adults. Although multiple studies have stressed the multifactorial and multigenic nature of HT, uncertainties about its etiology persist, and current diagnostic biomarkers can explain only a small part of the phenotypic variance of BP. Hence, the search for novel biomarkers that enable early disease prevention and guided therapy is warranted. Regulatory circRNAs have emerged as the newest player in HT-related gene networks and hold promise for improving the accuracy of diagnosis. These RNAs are genome products that are formed through back-splicing of specific regions of pre-mRNAs. Evidence suggests that these RNA species are involved in various metabolic diseases. Recent studies have revealed that aberrant expression of circRNAs is relevant to the occurrence and development of HT. Accordingly, circRNAs are proposed as a new generation of predictive biomarkers and potential therapeutic targets for different forms of HT, including pulmonary hypertension and preeclampsia. This paper presents an overview of the findings from current research focusing on the emerging role of circRNAs in the pathogenesis of hypertension. Furthermore, some of the challenges encountered by circRNA studies are highlighted, and perspectives are provided on the future of research in this area.

The Role of Epigenetics in Placental Development and the Etiology of Preeclampsia

In this review, we comprehensively present the function of epigenetic regulations in normal placental development as well as in a prominent disease of placental origin, preeclampsia (PE). We describe current progress concerning the impact of DNA methylation, non-coding RNA (with a special emphasis on long non-coding RNA (lncRNA) and microRNA (miRNA)) and more marginally histone post-translational modifications, in the processes leading to normal and abnormal placental function. We also explore the potential use of epigenetic marks circulating in the maternal blood flow as putative biomarkers able to prognosticate the onset of PE, as well as classifying it according to its severity. The correlation between epigenetic marks and impacts on gene expression is systematically evaluated for the different epigenetic marks analyzed.

miR‑342‑3p suppresses cell migration and invasion in preeclampsia by targeting platelet‑derived growth factor receptor α

miR-342-3p expression was increased in the placentas of women with preeclampsia (PE) according to previous examinations; the mechanism underlying the development and progression of PE requires further investigation. The present study aimed to explore the mechanism and functionality of microRNA (miR)-342-3p in trophoblastic cells. The expression of miR-342-3p and platelet-derived growth factor receptor α (PDGFRA) in the placentas of 30 patients with PE and 30 normal controls was detected. In addition, HTR8/SVneo cells were transfected with miR-342-3p mimics, small interfering RNA (siR)-PDGFRA or their corresponding negative controls; then the proliferation, migration, invasion and the distribution of the cell cycle of these cells were analyzed. Additionally, a dual-luciferase reporter assay was performed. According to these analyses, the expression of miR-342-3p was significantly increased, while that of PDGFRA was significantly lower in the PE group compared with the normal group. Transfection with miR-342-3p mimics led to a significant decrease in cell proliferation, migration and invasion, and also affected the cell cycle. Furthermore, miR-342-3p mimics reduced the expression of PDGFRA; miR-342-3p overexpression also reduced the mRNA and protein levels of BCL-2 and Caspase-3. In addition, transfection of siR-PDGFRA exhibited similar effects to those of miR-342-3p mimics. Finally, PDGFRA was reported to be a direct target of miR-342-3p. In conclusion, miR-342-3p was proposed to inhibit the proliferation, migration, invasion and G1/S phase transition of HTR8/SVneo cells by suppressing PDGFRA. Our findings suggest that miR-342-3p may be a novel clinical indicator or prognostic marker for PE.

HIF-1α Stabilization Increases miR-210 Eliciting First Trimester Extravillous Trophoblast Mitochondrial Dysfunction

Preeclampsia is associated with first trimester placental dysfunction. miR-210, a small non-coding RNA, is increased in the preeclamptic placenta. The effects of elevated miR-210 on placental function remain unclear. The objectives of this study were to identify targets of miR-210 in first trimester primary extravillous trophoblasts (EVTs) and to investigate functional pathways altered by elevated placental miR-210 during early pregnancy. EVTs isolated from first trimester placentas were exposed to cobalt chloride (CoCl₂), a HIF-1α stabilizer and hypoxia mimetic, and miR-210 expression by qPCR, HIF1α protein levels by western blot and cell invasion were assessed. A custom TruSeq RNA array, including all known/predicted miR-210 targets, was run using miR-210 and miR-negative control transfected EVTs. Mitochondrial function was assessed by high resolution respirometry in transfected EVTs. EVTs exposed to CoCl₂ showed a dose and time-dependent increase in miR-210 and HIF1α and reductions in cell invasion. The TruSeq array identified 49 altered genes in miR-210 transfected EVTs with 27 genes repressed and 22 enhanced. Three of the top six significantly repressed genes, NDUFA4, SDHD, and ISCU, are associated with mitochondrial function. miR-210 transfected EVTs had decreased maximal, complex II and complex I+II mitochondrial respiration. This study suggests that miR-210 alters first trimester trophoblast function. miR-210 overexpression alters EVT mitochondrial function in early pregnancy. Mitochondrial dysfunction may lead to increased reactive oxygen species, trophoblast cell damage and likely contributes to the pathogenesis of preeclampsia.

Role of Circular RNAs in Preeclampsia

Circular RNAs (circRNAs) are noncoding RNAs characterized by circular covalently closed structures, which are generated by back-splicing. circRNA is more stable and conserved than linear RNA and exists in various organisms. Preeclampsia (PE), a common hypertensive disorder of pregnancy, has a profound impact on maternal and neonatal mortality and morbidity. Recent studies demonstrated that circRNAs were differentially expressed in PE maternal-fetal interface compared with those in the control and might mediate pathological processes in pregnancy complications. However, the mechanisms of action of circRNAs in PE are still unclear. Here, we provide a comprehensive review on the current state of knowledge on circRNAs associated with PE. We summarize the known expression profiles of circRNAs and discuss their potential application as biomarkers of PE. The possible mechanisms underlying circRNA dysregulation in the etiology of PE are also explored.

Identification of Key circRNAs/lncRNAs/miRNAs/mRNAs and Pathways in Preeclampsia Using Bioinformatics Analysis

BACKGROUND This study aimed to identify significantly altered circRNAs/lncRNAs/miRNAs/mRNAs pathways in preeclampsia (PE), investigate their target relationships, and determine their biological functions. MATERIAL AND METHODS Base on RNA-seq technique and the GEO database, expression profiles of circRNAs/lncRNAs/miRNAs/mRNAs related to PE were obtained. Differentially expressed RNAs were determined using the Limma package in R. Gene set enrichment analysis (GSEA) was performed using GSEA software (v. 3.0) and illustrated by ClusterProfiler and ggplot2 package in R. DAVID database (v. 6.8) was implemented to analyze functional categories and the association between genes and the corresponding Gene Ontology (GO) classification. The R visualization package GOPlot was used to get a better visualization of the relationships between genes and the selected functional categories. CeRNA networks which visualized the correlations between circRNA/lncRNA-miRNA-mRNA were constructed using Cytoscape software (v. 3.6.0). Targetscan and miRanda database were used to predict target relationships between circRNA/lncRNA-miRNA-mRNA. QRT-PCR and luciferase reporter assay were used to verify the expression and target relationship of has_circ_0088196/LINC01492/miR-100-5p/LIF (leukemia inhibitory factor). RESULTS The jak-stat signaling pathway was activated and miR-100-5p was downregulated in PE compared with normal tissues both in collected placental tissue samples and GEO database. Upregulated LIF, LINC01492, and hsa_circ_0088196 were negatively correlated with miR-100-5p expression and had a targeted relationship with miR-100-5p. CONCLUSIONS miR-100-5p may suppress PE development, while LIF, LINC01492, and hsa_circ_0088196 may promote it though inhibiting miR-100-5p. The jak-stat signaling pathway was activated and involved in PE progression.

Circulating exosomal and Argonaute-bound microRNAs in preeclampsia

INTRODUCTION

microRNAs (miRNAs) play important role in the regulation of placental development, and abnormal miRNA expression is associated with preeclampsia (PE). miRNAs are released from trophoblast cells to maternal blood flow, where they are highly stable, being encapsulated inside extracellular vesicles, like exosomes or bound to Argonaute proteins. In PE, placental dysfunction leads to aberrant extracellular miRNA secretion. hsa-miR-210 is a hypoxia-sensitive miRNA found to be upregulated in PE; however, it is unknown whether it is the cause or the consequence of the disease.

OBJECTIVE

Our aim was to analyze the expression of several miRNAs, including hsa-miR-210 in placenta, exosome and Ago-bound fractions comparing normal (N) and PE pregnancies. We performed in vitro analyses of extracellular hsa-miR-210 secretion of trophoblast cell cultures (of villous and extravillous origin) under hypoxic condition.

METHODS

PE and N placenta samples were collected from C-sections, and blood samples were drawn from each pregnant woman in the third trimester. HTR-8 and JAR cell lines were cultured in exosome-free media and treated with hypoxia-mimetic agents. Exosome and Ago-bound fractions were isolated by membrane affinity spin column method from plasma and cell media. Short RNAs were extracted from exosomes and vesicle-free fractions, and total-RNA was isolated from the placenta samples. The RNA purity and concentration were measured by spectrophotometry. Expression analysis was carried out by qPCR with specific primers to target and reference miRNAs.

RESULTS

The level of hsa-miR-210 was significantly higher in PE placentas, which could cause a minor increase of exosomal and a high elevation of Ago-bound miR-210 in circulation. Hypoxia lead to intracellular hsa-miR-210 upregulation in trophoblast cell lines. In extravillous cell (HTR-8) media, only the level of exosomal hsa-miR-210 was increased but no change in Ago-bound hsa-miR-210 level was observed. In contrast, in villous cell (JAR) media, the level of exosomal hsa-miR-210 was increased and enhanced release of Ago-bound hsa-miR-210 was also observed.

CONCLUSION

Based on our data, we postulate that in PE, exosomal hsa-miR-210 is secreted actively from the trophoblast, and by intercellular communication, it may have a role in disease etiology. In addition, there is a passive release of Ago-bound hsa-miR-210 into the circulation, which may represent by-products of cell-death and is thereby a possible consequence of the disease.

Competing endogenous RNA expression profiling in pre-eclampsia identifies hsa_circ_0036877 as a potential novel blood biomarker for early pre-eclampsia

Background

The etiology and pathogenesis of pre-eclampsia (PE) is unclear, and there is no ideal early clinical biomarker for prediction of PE. The competing endogenous RNA (ceRNA) hypothesis is a new approach to uncover the molecular pathology of PE. The first aim of this study was to perform messenger RNA, long non-coding RNA, and circular RNA (circRNA) expression profiling of human normal and severe pre-eclampsia (SPE) placentas. circRNA, which has a stable structure, is a more suitable biomarker than other types of RNA. Therefore, the second aim of our study was to select some differentially expressed circRNAs in PE placentas as early clinical biomarkers of PE in blood circulation.

Results

Using microarray analysis, we investigated differentially expressed ceRNAs in human normal and SPE placentas. Bioinformatics, such as gene ontology, KEGG pathway, and ceRNA network analyses, were performed to evaluate the microarray data and gain further insights into the biological processes. RNAs (Chd5, Furin, lnc-ELAVL4-9:1, lnc-RAP1GAP2-5:2, hsa_circ_0036877, hsa_circ_0036878, hsa_circ_0055724, hsa_circ_0049730, and hsa_circ_0036474) were validated by quantitative real-time PCR (qRT-PCR). RNA immunoprecipitation (RIP) of AGO2 in htra-8 cells and qRT-PCR analysis of hsa_circ_0036877 expression in maternal whole peripheral blood samples of participants were then conducted to confirm that hsa_circ_0036877 is a ceRNA and potential novel blood biomarker for early PE, respectively.

Conclusion

Our study is the first systematic profiling of ceRNAs in placentas of PE patients and revealed the global ceRNA network integration in PE. Moreover, hsa_circ_0036877 can function as a ceRNA and serve as a potential novel blood biomarker for early PE.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0482-3) contains supplementary material, which is available to authorized users.

Development of a miRNA surface-enhanced Raman scattering assay using benchtop and handheld Raman systems

DNA-functionalized nanoparticles, when paired with surface-enhanced Raman spectroscopy (SERS), can rapidly detect microRNA. However, widespread use of this approach is hindered by drawbacks associated with large and expensive benchtop Raman microscopes. MicroRNA-17 (miRNA-17) has emerged as a potential epigenetic indicator of preeclampsia, a condition that occurs during pregnancy. Biomarker detection using an SERS point-of-care device could enable prompt diagnosis and prevention as early as the first trimester. Recently, strides have been made in developing portable Raman systems for field applications. An SERS assay for miRNA-17 was assessed and translated from traditional benchtop Raman microscopes to a handheld system. Three different photoactive molecules were compared as potential Raman reporter molecules: a chromophore, malachite green isothiocyanate (MGITC), a fluorophore, tetramethylrhodamine isothiocyanate, and a polarizable small molecule 5,5-dithio-bis-(2-nitrobenzoic acid) (DTNB). For the benchtop Raman microscope, the DTNB-labeled assay yielded the greatest sensitivity under 532-nm laser excitation, but the MGITC-labeled assay prevailed at 785 nm. Conversely, DTNB was preferable for the miniaturized 785-nm Raman system. This comparison showed significant SERS enhancement variation in response to 1-nM miRNA-17, implying that the sensitivity of the assay may be more heavily dependent on the excitation wavelength, instrumentation, and Raman reporter chosen than on the plasmonic coupling from DNA/miRNA-mediated nanoparticle assemblies.

Various levels of circulating exosomal total-miRNA and miR-210 hypoxamiR in different forms of pregnancy hypertension

INTRODUCTION

Hypertension is a common complication during pregnancy, affecting 10% of pregnant women worldwide. Several microRNA (miRNA) were shown to be involved in hypertensive disorders of pregnancy. In preeclampsia (PE), placental dysfunction causes the enhanced release of extracellular vesicle-derived miRNAs. The hypoxia-sensitive hsa-mir-210 is the most common PE-associated miRNA, but its exosomal profile has not been investigated.

OBJECTIVES

Our aims were to measure exosomal total-miRNA concentration and to perform expression analysis of circulating exosomal hsa-miR-210 in women affected by chronic hypertension (CHT) gestational hypertension (GHT) or PE.

MATERIALS AND METHODS

We collected plasma samples from women with CHT, GHT, PE (moderate: mPE and severe: sPE) and from normotensive pregnancies. Exosomal miRNAs were extracted and miRNA concentration was measured. RT-PCR was carried out with hsa-miR-210-3p-specific primers and relative expression was calculated using the comparative Ct method.

RESULTS

The total-miRNA concentration was different in the disease subgroups, and was significantly higher in mPE and sPE compared to the other groups. We found a significant difference in the relative exosomal hsa-miR-210-3p expression between all hypertensive groups compared to the normotensive samples, but significant upregulation was only observed in case of mPE and sPE patients. Both the level of total-miRNA and hsa-miR-210 expression was higher in case of severe PE.

CONCLUSIONS

The level of circulating exosomal total-miRNA and hsa-miR-210 was elevated in women with PE, and it was higher in the severe form. We showed that hsa-miR-210 is secreted via exosomes, which may have a role in the pathomechanism of the disease.

New Insights into the Role of Matrix Metalloproteinases in Preeclampsia

Preeclampsia is a severe pregnancy complication globally, characterized by poor placentation triggering vascular dysfunction. Matrix metalloproteinases (MMPs) exhibit proteolytic activity implicated in the efficiency of trophoblast invasion to the uterine wall, and a dysregulation of these enzymes has been linked to preeclampsia. A decrease in MMP-2 and MMP-9 interferes with the normal remodeling of spiral arteries at early pregnancy stages, leading to the initial pathophysiological changes observed in preeclampsia. Later in pregnancy, an elevation in MMP-2 and MMP-9 induces abnormal release of vasoactive factors conditioning hypertension. Although these two enzymes lead the scene, other MMPs like MMP-1 and MMP-14 seem to have a role in this pathology. This review gathers published recent evidence about the implications of different MMPs in preeclampsia, and the potential use of these enzymes as emergent biomarkers and biological therapeutic targets, focusing on studies involving human subjects.