Circulating microRNAs as biomarkers for diagnosis and prediction of preeclampsia: A systematic review and meta-analysis

Value of Non-Coding RNA Expression in Biofluids to Identify Patients at Low Risk of Pathologies Associated with Pregnancy

Pregnancy-related complications (PRC) impact maternal and fetal morbidity and mortality and place a huge burden on healthcare systems. Thus, effective diagnostic screening strategies are crucial. Currently, national and international guidelines define patients at low risk of PRC exclusively based on their history, thus excluding the possibility of identifying patients with de novo risk (patients without a history of disease), which represents most women. In this setting, previous studies have underlined the potential contribution of non-coding RNAs (ncRNAs) to detect patients at risk of PRC. However, placenta biopsies or cord blood samples are required, which are not simple procedures. Our review explores the potential of ncRNAs in biofluids (fluids that are excreted, secreted, or developed because of a physiological or pathological process) as biomarkers for identifying patients with low-risk pregnancies. Beyond the regulatory roles of ncRNAs in placental development and vascular remodeling, we investigated their specific expressions in biofluids to determine favorable pregnancy outcomes as well as the most frequent pathologies of pregnant women. We report distinct ncRNA panels associated with PRC based on omics technologies and subsequently define patients at low risk. We present a comprehensive analysis of ncRNA expression in biofluids, including those using next-generation sequencing, shedding light on their predictive value in clinical practice. In conclusion, this paper underscores the emerging significance of ncRNAs in biofluids as promising biomarkers for risk stratification in PRC. The investigation of ncRNA expression patterns and their potential clinical applications is of diagnostic, prognostic, and theragnostic value and paves the way for innovative approaches to improve prenatal care and maternal and fetal outcomes.

Circulating miRNAs and Preeclampsia: From Implantation to Epigenetics

In this review, we comprehensively present the literature on circulating microRNAs (miRNAs) associated with preeclampsia, a pregnancy-specific disease considered the primary reason for maternal and fetal mortality and morbidity. miRNAs are single-stranded non-coding RNAs, 20-24 nt long, which control mRNA expression. Changes in miRNA expression can induce a variation in the relative mRNA level and influence cellular homeostasis, and the strong presence of miRNAs in all body fluids has made them useful biomarkers of several diseases. Preeclampsia is a multifactorial disease, but the etiopathogenesis remains unclear. The functions of trophoblasts, including differentiation, proliferation, migration, invasion and apoptosis, are essential for a successful pregnancy. During the early stages of placental development, trophoblasts are strictly regulated by several molecular pathways; however, an imbalance in these molecular pathways can lead to severe placental lesions and pregnancy complications. We then discuss the role of miRNAs in trophoblast invasion and in the pathogenesis, diagnosis and prediction of preeclampsia. We also discuss the potential role of miRNAs from an epigenetic perspective with possible future therapeutic implications.

Correlation and predictive value of serum miR-146b-5p expression during the first trimester of pregnancy with pre-eclampsia

The aim of this study was to investigate the correlation and predictive value of serum miR-146b-5p expression during the first trimester of pregnancy with pre-eclampsia (PE). In total, 32 normal pregnant women (the control group) and 58 subjects with PE were randomly selected from eligible case data. The serum levels of miR-146b-5p, pregnancy associated plasma protein A (PAPP-A) and free beta subunit of human chorionic gonadotropin (free β-hCG) were then detected. Next, we established predictive models of single or multiple markers for PE. The levels of miR-146b-5p in the mild pre-eclampsia (mPE) and severe pre-eclampsia (sPE) groups were higher than the control group and there were significant differences between the three groups (F = 3.424, P = 0.037). The statistical results of the model before and after 200 times 10-fold cross-validation were as follows: miR-146b-5p (AUC = 0.723 vs AUC = 0.710); miR-146b-5p + BMI + MAP + free β-hCG MoM + PAPP-A MoM (AUC = 0.929 vs AUC = 0.851). We found that expression levels of miR-146b-5p in the first trimester were significantly higher in the serum of pregnant women with PE than in the normal pregnancy group. A prediction model in combination with miR-146b-5p and other markers improved the early predictive value for PE.IMPACT STATEMENTWhat is already known on this subject? Pre-eclampsia is a complex systemic disease with hypertension as the main clinical manifestation and causes extensive damage to the body. Some existing maternal biochemical markers have limited value in predicting PE, and new biomarkers with high sensitivity and specificity are urgently needed in clinical practice. There are a variety of abnormal expression miRNAs in PE, however, the relationship between miR-146b-5p and PE has yet to be fully elucidated.What do the results of this study add? We first found that expression levels of serum miR-146b-5p in the first trimester were significantly higher in PE than in a normal pregnancy group. A prediction model a combination of miR-146b-5p and other maternal characteristics and biochemical markers can improve the early predictive value for PE.What are the implications of these findings for clinical practice and/or further research? PE progresses rapidly and has become a severe target organ complication when discovered. Therefore, the early prediction of a high risk of PE, along with early intervention and prevention measures, are of great significance. Compared to maternal biochemical markers, combination of miR-146b-5p and maternal characteristics and biochemical markers can improve the early predictive value for PE.

Small Non-Coding RNAs in the Human Placenta: Regulatory Roles and Clinical Utility

The placenta is a vital organ formed during pregnancy, and being the interface between the mother and fetus, it is paramount that placental functioning is strictly controlled. Gene expression in the placenta is finely tuned-with aberrant expression causing placental pathologies and inducing stress on both mother and fetus. Gene regulation is brought upon by several mechanisms, and small non-coding RNAs (sncRNAs) have recently been appreciated for their contribution in gene repression. Their dysregulation has been implicated in a range of somatic and inherited disorders, highlighting their importance in maintaining healthy organ function. Their specific roles within the placenta, however, are not well understood, and require further exploration. To this end, we summarize the mechanisms of microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs), small nuclear RNAs (snRNAs), small nucleolar RNAs (snoRNAs), and transfer RNAs (tRNAs), their known contributions to human placental health and disease, the relevance of sncRNAs as promising biomarkers throughout pregnancy, and the current challenges faced by placental sncRNA studies.

Overexpression of microRNAs miR-25-3p, miR-185-5p and miR-132-3p in Late Onset Fetal Growth Restriction, Validation of Results and Study of the Biochemical Pathways Involved

In a prospective study, 48 fetuses were evaluated with Doppler ultrasound after 34 weeks and classified, according to the cerebroplacental ratio (CPR) and estimated fetal weight (EFW), into fetuses with normal growth and fetuses with late-onset fetal growth restriction (LO-FGR). Overexpression of miRNAs from neonatal cord blood belonging to LO-FGR fetuses, was validated by real-time PCR. In addition, functional characterization of overexpressed miRNAs was performed by analyzing overrepresented pathways, gene ontologies, and prioritization of synergistically working miRNAs. Three miRNAs: miR-25-3p, miR-185-5p and miR-132-3p, were significantly overexpressed in cord blood of LO-FGR fetuses. Pathway and gene ontology analysis revealed over-representation of certain molecular pathways associated with cardiac development and neuron death. In addition, prioritization of synergistically working miRNAs highlighted the importance of miR-185-5p and miR-25-3p in cholesterol efflux and starvation responses associated with LO-FGR phenotypes. Evaluation of miR-25-3p; miR-132-3p and miR-185-5p might serve as molecular biomarkers for the diagnosis and management of LO-FGR; improving the understanding of its influence on adult disease.

Circulating noncoding RNAs as early predictive biomarkers in preeclampsia: a diagnostic meta-analysis

BACKGROUND

We designed a meta-analysis to evaluate the clinical significance and efficacy of circulating noncoding RNAs (ncRNAs) in the early prediction of preeclampsia.

METHODS

PubMed, Embase and the Cochrane Library were used to search for literature. The combined prediction performance was evaluated by calculating the area under the summary receiver operator characteristic (SROC) curve. The potential sources of heterogeneity were analysed by meta-regression analysis and subgroup analysis. All statistical analyses and mapping were performed by RevMan 5.3 and Stata 12.0.

RESULTS

A total of 41 studies from 14 articles, including 557 preeclampsia patients and 842 controls, were included in our meta-analysis. All studies collected blood before onset. NcRNAs in blood performed relatively well in predicting preeclampsia. The combined sensitivity was 0.71, the specificity was 0.84, and the area under the SROC curve (AUC) was 0.86. Peripheral blood mononuclear cell (PBMC) samples showed the best diagnostic accuracy. The combined AUC was 0.93. Combined detection was better than single detection, and miRNA was better than circRNA. The heterogeneity of the study was determined by sample size, lncRNA characteristics, lncRNA source and race.

CONCLUSION

Circulating ncRNAs can be valuable biomarkers used as candidates for noninvasive early predictive biomarkers of preeclampsia and have great clinical application prospects. The clinical value of ncRNAs needs to be tested by further multicentre, comprehensive and prospective studies, and the test criteria should be established.

The Value of Circulating microRNAs for Diagnosis and Prediction of Preeclampsia: a Meta-analysis and Systematic Review

Preeclampsia (PE) is one of the main causes of maternal death worldwide, but our understanding of the molecular characteristics of disease progression is limited. In this meta-analysis, we aimed to assess the value of peripheral blood microRNAs (miRNAs) as diagnostic and predictive markers of PE. We screened PubMed, Web of Science, and Embase databases; searched articles about "miRNAs and PE" up to November 30, 2020; and conducted biological information and subgroup analysis. We used QUADAS-2 (quality assessment of diagnostic accuracy studies-2) to evaluate the included articles by two independent reviewers, calculated the combined diagnostic and predictive indicators using the random effects model, explored the sources of potential heterogeneity through subgroup analysis, and evaluated publication bias using Deeks' funnel plot asymmetry test using Stata 14.0 and Review Manager 5.3 software. Forty-three miRNAs from 15 studies, including 2042 healthy controls and 2685 PE patients, had a pooled sensitivity of 0.86 (95% CI: 0.81-0.90), specificity of 0.89 (95% CI: 0.85-0.92), and an AUC of 0.94 (95% CI: 0.91-0.96). Moreover, before 20 weeks of gestation, the combined sensitivity was 0.86 (95% CI: 0.75-0.92), and the specificity was 0.90 (95% CI: 0.83-0.95), which indicated that some of the circulating miRNAs had changed significantly before the clinical symptoms appeared in PE patients. Circulating miRNAs have high diagnostic and predictive accuracy and may be used as non-invasive biomarkers for the diagnosis and prediction of PE. However, a large sample prospective study is still needed.

Non-Coding RNAs in Preeclampsia-Molecular Mechanisms and Diagnostic Potential

Preeclampsia (PE) is a leading cause of maternal and neonatal morbidity and mortality worldwide. Defects in trophoblast invasion, differentiation of extravillous trophoblasts and spiral artery remodeling are key factors in PE development. Currently there are no predictive biomarkers clinically available for PE. Recent technological advancements empowered transcriptome exploration and led to the discovery of numerous non-coding RNA species of which microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) are the most investigated. They are implicated in the regulation of numerous cellular functions, and as such are being extensively explored as potential biomarkers for various diseases. Altered expression of numerous lncRNAs and miRNAs in placenta has been related to pathophysiological processes that occur in preeclampsia. In the following text we offer summary of the latest knowledge of the molecular mechanism by which lnRNAs and miRNAs (focusing on the chromosome 19 miRNA cluster (C19MC)) contribute to pathophysiology of PE development and their potential utility as biomarkers of PE, with special focus on sample selection and techniques for the quantification of lncRNAs and miRNAs in maternal circulation.

Effect of lncRNA-ATB/miR-651-3p/Yin Yang 1 pathway on trophoblast-endothelial cell interaction networks

Our previous studies have confirmed that lncRNA‐ATB may be involved in the pathogenesis of preeclampsia, however, it is uncertain whether lncRNA‐ATB influence the interaction between trophoblast and endothelial cells, which is crucial to the uterine spiral artery remodelling. Scratch wound healing and transwell invasion assay were conducted to test the migration and invasion of trophoblast cells. Co‐culture model was used to simulate the physiological environment in vivo. The expression levels of lncRNA‐ATB were analyzed in placenta tissues from healthy pregnant women and preeclampsia patients. Subsequently, the binding site of lncRNA‐ATB and miR‐651‐3p was verified using dual‐luciferase reporter assay, and the rescue experiment was used to study the effects of these two on the biological function. The direct effects of miR‐651‐3p and Yin Yang 1 (YY1) were verified using similar methods. LncRNA‐ATB was found to be down‐regulated in the placenta of preeclampsia patients. LncRNA‐ATB knockdown decreased trophoblast migration, invasion and colocalisation with human umbilical vein endothelial cells. MiR‐651‐3p was a direct target of lncRNA‐ATB and they had opposite effects. Moreover, the expression of lncRNA‐ATB and miR‐651‐3p in placental tissues was negatively correlated. MiR‐651‐3p has been confirmed to directly target the 3′ untranslated region of YY1. The inhibitory effects of YY1 low expression on biological function was rescued by miR‐651‐3p depletion. Western blot analysis showed that lncRNA‐ATB could regulate YY1 expression by sponging miR‐651‐3p. LncRNA‐ATB functioned as a competitive endogenous RNA of miR‐651‐3p to regulate YY1 on progress of spiral artery remodelling.

Association of Circulating miRNA Expression with Preeclampsia, Its Onset, and Severity

MicroRNAs (miRNAs) are one of the important regulators of cellular functions fundamental for healthy pregnancy processes, including angiogenesis and differentiation of trophoblast cells, and their deregulation could be implicated in the pathogenesis of pregnancy complications, including preeclampsia (PE). The aim of this study was to assess the association of miRNA expression in plasma samples with PE, its onset, and severity. Our study enrolled 59 pregnant women, 27 in the preeclamptic study group and 32 in the control group with physiological pregnancy. Preeclamptic pregnancies were divided into subgroups based on the severity and onset of disease. Relative expression of miR-21-5p, miR-155-5p, miR-210-5p, miR-16-5p, and miR-650 isolated from plasma samples was analysed by quantitative real-time PCR and normalised to experimentally established reference genes. Our results revealed upregulation of miR-21-5p (1.16-fold change, p = 0.0015), miR-155-5p (1.62-fold change, p = 0.0005) in preeclamptic pregnancies, compared to controls. Overexpression of these two miRNAs was observed, especially in subgroups of severe and late-onset PE compared to healthy pregnancies. Although we hypothesised that the expression level of studied miRNAs could vary between PE subtypes (mild vs. severe, early onset vs. late-onset), no obvious differences were detected. In conclusion, our study could contribute to the large-scale studies for the identification of non-invasive biomarkers for PE detection to improve outcomes for women and their new-borns.