Extracellular vesicle microRNA in early versus late pregnancy with birth outcomes in the MADRES study

Optimizing Protocols for MicroRNA Profiling of Infant and Toddler Stool

Background

MicroRNAs (miRNAs) are increasingly being investigated as potential biomarkers for child development and disease. Although a growing number of studies are utilizing infant and toddler stool for transcriptomic analyses, no studies have compared protocols for preserving and extracting miRNAs from this specimen type, despite unique challenges, including abundant levels of RNAses and microbial RNA.

Methods

To address this, we first compared three commercially available kits and four preservation methods for their ability to yield high quality RNA from infant and toddler stool (Phase 1). RNA quality was determined by fragment analyzer.

Results

Of the three RNA extraction kits compared, Zymo BIOMICs yielded the highest overall RNA Quality Number (RQN) (median (range) RQN 9.4 (5.7-10.0)). Of the four preservation methods tested, stool collected in RNAlater and Zymo DNA/RNA Shield Fecal Collection Tubes yielded the highest two RQNs (median (range) RQN 9.8 (5.7-10.0) and 9.4 (5.4-10.0), respectively), which did not differ significantly from each other ( p = 0.47). Second, using miRNA-seq we directly compared miRNA profiles for RNA extracted using the Zymo BIOMICs kit from paired aliquots of the same stool sample from four infants collected into RNAlater and Zymo DNA/RNA Shield Fecal Collection Tubes (Phase 2). Given that microbial sequences greatly outnumber human miRNAs in stool, reads were first classified as human versus microbial prior to aligning human-classified reads to miRBase v22.1. The percentage of reads classified as human and the percentage of human reads aligning to miRBase did not differ for samples collected in RNAlater versus Zymo Shield ( p = 0.12 and p = 0.86, respectively). Furthermore, after multiple testing correction, normalized miRNA counts did not differ significantly between the two preservatives for any of the 42 human miRNAs detected across the eight samples.

Conclusions

Collecting infant and toddler stool in either RNAlater or Zymo DNA/RNA Shield Fecal Collection Tubes, when paired with RNA extraction using the Zymo BIOMICs extraction kit, yielded high-quality RNA with similar human miRNA profiles. Moreover, of the 42 miRNAs that were detected, several (i.e., miR-194a-3p, miR-200c-3p, miR-26a-5p) are thought to contribute to overall gut homeostasis. These findings may inform protocols for future studies that aim to profile miRNAs in infant and toddler stool to evaluate their potential utility as biomarkers for children's health.

Decreased Extracellular Vesicle Vasorin in Severe Preeclampsia Plasma Mediates Endothelial Dysfunction

BACKGROUND

Preeclampsia is a serious pregnancy complication affecting 5% to 8% of pregnancies globally. preeclampsia is a leading cause of maternal and neonatal morbidity and death. Despite its prevalence, the underlying mechanisms of preeclampsia remain unclear. This study investigated the role of vasorin in preeclampsia pathogenesis by examining its levels in extracellular vesicles (EVs) and effects on vascular function.

METHODS AND RESULTS

We conducted unbiased proteomics on urine-derived EVs from women with severe preeclampsia and normotensive pregnancies, identifying differentially abundant proteins. Vasorin expression levels were measured in urinary EVs, plasma EVs, and placental tissue. EVs were generated from human and murine placental explants. Vascular functions were assessed using murine aortic rings and human aortic endothelial cells. Vasorin expression was manipulated in human aortic endothelial cells via overexpression and knockdown followed by RNA sequencing. One hundred twenty proteins showed ≥±1.5-fold regulation (P<0.05) between severe preeclampsia and NTP. Vasorin levels decreased in severe preeclampsia in urinary EVs, plasma EVs, and placental tissue. Vasorin levels increased with gestational age in murine pregnancy and were diminished in a murine model of preeclampsia. Severe preeclampsia and murine preeclampsia EVs impaired human aortic endothelial cell migration and inhibited murine aortic ring vasorelaxation. Vasorin overexpression counteracted these effects. RNA sequencing showed that vasorin manipulation in human aortic endothelial cells differentially regulated hundreds of genes linked to vasculogenesis, proliferation, migration, and apoptosis.

CONCLUSIONS

The data suggest that vasorin, delivered to the endothelium via EVs, regulates vascular function and that the loss of EV vasorin may be one of the mechanistic drivers of preeclampsia.

Maternal diet quality and circulating extracellular vesicle and particle miRNA during pregnancy

PURPOSE

During pregnancy, extracellular vesicle and particle microRNAs (EVP miRNA) in maternal circulation have the capacity to cross the placenta and facilitate maternal-fetal communication. Both dysregulation of circulating EVP miRNA during pregnancy and maternal diet quality have been previously associated with pregnancy complications and adverse birth outcomes. However, little is known about how maternal diet influences circulating EVP miRNA during pregnancy. This study assesses associations between maternal diet quality, as measured by the Alternative Healthy Eating Index (2010; AHEI-2010), and EVP miRNA levels in maternal circulation during pregnancy.

METHODS

In a pilot study of 53 pregnant participants in the New Hampshire Birth Cohort Study, maternal diet quality was assessed using AHEI-2010 and plasma (mean gestational age at blood collection: 28.8 weeks) EVP miRNA were profiled using the NanoString nCounter platform which interrogates 798 miRNA transcripts.

RESULTS

In covariate-adjusted models, the AHEI-2010 adherence score was negatively associated (P < 0.05) with the number of unique miRNA transcripts detectable in each sample. In post hoc analyses, greater consumption of red and processed meats was positively associated with levels of 7 miRNA (Q < 0.05), including hsa-miR-512-5p (PBonf < 0.01), a member of the placenta-specific chromosome 19 miRNA cluster.

CONCLUSION

We identified associations between the consumption of red and processed meat and levels of circulating select EVP miRNA during pregnancy, including placenta-specific miRNA and miRNA with target genes overrepresented in pathways involved in placental development. Additional research is needed to assess whether alterations in maternal circulating EVP miRNA may mediate maternal diet quality's impacts on pregnancy and birth outcomes.

Maternal glucose levels and late pregnancy circulating extracellular vesicle and particle miRNAs in the MADRES pregnancy cohort

Maternal hyperglycemia during pregnancy adversely affects maternal and child outcomes. While mechanisms are not fully understood, maternal circulating miRNAs may play a role. We examined whether continuous glucose levels and hyperglycemia subtypes (gestational diabetes, type 2 diabetes, and glucose intolerance) were associated with circulating miRNAs during late pregnancy. Seven miRNAs (hsa-miR-107, hsa-let-7b-5p, hsa-miR-126-3p, hsa-miR-181a-5p, hsa-miR-374a-5p, hsa-miR-382-5p, and hsa-miR-337-5p) were associated (p < 0.05) with either hyperglycemia or continuous glucose levels prior to multiple testing correction. These miRNAs target genes involved in pathways relevant to maternal and child health, including insulin signaling, placental development, energy balance, and appetite regulation.

Micro-RNA 7975 directly regulates MDTH expression and mediates endothelial cell proliferation and migration in the development of early atherosclerosis

Cardiovascular disease (CVD) is commonly due to the development of atherosclerosis. Endothelial integrity is critical in the prevention of pathogenesis of atherosclerosis. The key to prevention of CVD is understanding the molecular mechanisms responsible for initiation of early atherosclerosis. MiRNAs are mediators of endothelial homeostasis, and their dysregulation could lead to early atherosclerotic disorder. We previously revealed the expression of miR-7975 in early atherosclerotic lesions. The aim of this study was to investigate the novel roles of miR-7975 on endothelial cell proliferation and migration, and in the regulation of metadherin (MTDH) expression. We performed proliferation and migration assays coupled with luciferase assay. We show that miR-7975 promotes proliferation and migration of endothelial cells and that miR-7976 directly regulates (MTDH), previously associated with cancer pathogenesis. In conclusion our results show miR-7975 could be a potential mediator of endothelial homeostasis and that MTDH is a novel target of miR-7975.

Deregulation of MicroRNA-146a and 155 expression levels might underlie complicated pregnancy in Toxoplasma Gondii seronegative women

BACKGROUND

To evaluate the ability of the estimated plasma expression levels of genes of microRNA (MiR-) 146a and 155 to differentiate between samples of pregnant women suspected to be infected by T. gondii. 50 newly pregnant women who had at least one of the criteria of high risk for toxoplasma infection and 50 newly primigravida women free of these criteria gave blood samples for qualitative determination of serum toxoplasma antibodies and estimation of plasma expression levels of MiR-146a and 155 using the qRT-PCR. During the pregnancy course, the incidence of pregnancy complications was recorded.

RESULTS

Twenty-six women were IgM-/IgG-, 17 women were IgM+/IgG- and 7 women were IgM+/IgG+. Thirty-two women had pregnancy complications with significantly lower incidence in IgM-/IgG- women. Plasma expression levels of MiR-146a and 155 were significantly higher in total patients compared to control levels and were significantly higher in samples of IgM+/IgG+ patients than in other samples. Statistical analyses defined a high plasma level of MiR-155 as the highly significant predictor for oncoming pregnancy complications and high levels of both microRNAs as predictors for the presence of toxoplasmosis despite seronegativity. Kaplan-Meier regression analysis defined increasing cumulative risk of having toxoplasmosis despite seronegativity with plasma levels of MiR-146a and MiR-155 of 1.2 and 3, respectively.

CONCLUSION

The incidence of pregnancy complications is high, irrespective of the seronegativity of women at high risk of toxoplasmosis. Estimated plasma levels of MiR-155 might identify women liable to develop complications and differentiate seronegative women vulnerable to having T. gondii infection.

TRIAL REGISTRATION

The study protocol was approved preliminarily by the Local Ethical Committee at Benha Faculty of Medicine. Before enrollment, the study protocol was discussed in detail with the study participants, and those accepted to participate in the study signed written fully informed consents. The final approval of the study protocol was obtained after the end of case collection and registered by RC: 5-11-2022.

Decreased Extracellular Vesicle Vasorin in Severe Preeclampsia Plasma Mediates Endothelial Dysfunction

Background

Preeclampsia (PE) is a serious pregnancy complication affecting 5-8% of pregnancies globally. It is a leading cause of maternal and neonatal morbidity and mortality. Despite its prevalence, the underlying mechanisms of PE remain unclear. This study aimed to determine the potential role of vasorin (VASN) in PE pathogenesis by investigating its levels in extracellular vesicles (EV) and its effects on vascular function.

Methods & Results

We conducted unbiased proteomics on urine-derived EV from severe PE (sPE) and normotensive pregnant women (NTP), identifying differential protein abundances. Out of one hundred and twenty proteins with ≥ ±1.5-fold regulation at P<0.05 between sPE and NTP, we focused on Vasorin (VASN), which is downregulated in sPE in urinary EV, in plasma EV and in the placenta and is a known regulator of vascular function. We generated EV with high VASN content from both human and murine placenta explants (Plex EV), which recapitulated disease-state-dependent effects on vascular function observed when treating murine aorta rings (MAR) or human aortic endothelial cells (HAEC) with murine or human plasma-derived EV. In normal murine pregnancy, VASN increases with gestational age (GA), and VASN is decreased in plasma EV, in placenta tissue and in Plex EV after intravenous administration of adenovirus encoding short FMS-like tyrosine kinase 1 (sFLT-1), a murine model of PE (murine-PE). VASN is decreased in plasma EV, in placenta tissue and in EV isolated from conditioned media collected from placenta explants (Plex EV) in patients with sPE as compared to NTP. Human sPE and murine-PE plasma EV and Plex EV impair migration, tube formation, and induces apoptosis in human aortic endothelial cells (HAEC) and inhibit acetylcholine-induced vasorelaxation in murine vascular rings (MAR). VASN over-expression counteracts the effects of sPE EV treatment in HAEC and MAR. RNA sequencing revealed that over-expression or knock down of VASN in HAEC results in contrasting effects on transcript levels of hundreds of genes associated with vasculogenesis, endothelial cell proliferation, migration and apoptosis.

Conclusions

The data suggest that VASN, delivered to the endothelium via EV, regulates vascular function and that the loss of EV VASN may be one of the mechanistic drivers of PE.

CLINICAL PERSPECTIVE

What is NewVASN in circulating plasma EV in sPE is reduced compared with VASN content in plasma EV of gestational age-matched pregnant women.VASN is encapsulated and transported in EV and plays a pro-angiogenic role during pregnancy.VASN should be explored both for its pro-angiogenic mechanistic role and as a novel biomarker and potential predictive diagnostic marker for the onset and severity of PE.What Are the Clinical Implications?VASN plays a role in maintaining vascular health and the normal adaptive cardiovascular response in pregnancy. A decrease of VASN is observed in sPE patients contributing to cardiovascular maladaptation.Strategies to boost diminished VASN levels and/or to pharmacologically manipulate mechanisms downstream of VASN may be explored for potential therapeutic benefit in PE.The decrease in EV-associated VASN could potentially be used as a (predictive) biomarker for PE.

Epigenetic Responses to Nonchemical Stressors: Potential Molecular Links to Perinatal Health Outcomes

PURPOSE OF REVIEW

We summarize the recent literature investigating exposure to four nonchemical stressors (financial stress, racism, psychosocial stress, and trauma) and DNA methylation, miRNA expression, and mRNA expression. We also highlight the relationships between these epigenetic changes and six critical perinatal outcomes (preterm birth, low birth weight, preeclampsia, gestational diabetes, childhood allergic disease, and childhood neurocognition).

RECENT FINDINGS

Multiple studies have found financial stress, psychosocial stress, and trauma to be associated with DNA methylation and/or miRNA and mRNA expression. Fewer studies have investigated the effects of racism. The majority of studies assessed epigenetic or genomic changes in maternal blood, cord blood, or placenta. Several studies included multi-OMIC assessments in which DNA methylation and/or miRNA expression were associated with gene expression. There is strong evidence for the role of epigenetics in driving the health outcomes considered. A total of 22 biomarkers, including numerous HPA axis genes, were identified to be epigenetically altered by both stressors and outcomes. Epigenetic changes related to inflammation, the immune and endocrine systems, and cell growth and survival were highlighted across numerous studies. Maternal exposure to nonchemical stressors is associated with epigenetic and/or genomic changes in a tissue-specific manner among inflammatory, immune, endocrine, and cell growth-related pathways, which may act as mediating pathways to perinatal health outcomes. Future research can test the mediating role of the specific biomarkers identified as linked with both stressors and outcomes. Understanding underlying epigenetic mechanisms altered by nonchemical stressors can provide a better understanding of how chemical and nonchemical exposures interact.

Are Vascular Endothelium and Angiogenesis Effective MicroRNA Biomarkers Associated with the Prediction of Early-Onset Preeclampsia (EOPE) and Adverse Perinatal Outcomes?

MicroRNA is associated with angiogenesis, invasion, proliferation, and vascular endothelial remodeling of various diseases. We aimed to investigate serum MicroRNA (miRNA) levels in preeclampsia (PE) and to determine whether any changes in miRNA levels are useful in predicting early onset preeclampsia (EOPE) and adverse perinatal outcomes. A total of 89 pregnant patients were enrolled in this prospective case-control study (55 PE and 34 healthy controls). miR-17, miR-20a, miR-20b, miR126, miR155, miR-200, miR-222, and miR-210 levels were studied in maternal serum in preeclamptic pregnant women. Multiple logistic regression analyses analyzed the risk factors which are associated with EOPE and adverse maternal outcomes. The Real-time RT-PCR method was used to determine maternal serum miRNA levels. Serum miR-17, miR-20a, miR-20b, miR126, and miR-210 levels were significantly higher in PE than the control group (p < .001, p < .001, p < .001, p < .001 and p = .047 respectively). Increased miR-17, miR-20a, and miR-20b levels were independently associated with PE (OR: 0.642, 95%Cl: 0.486-0.846, p = .002; OR: 0.899, 95%Cl: 0.811-0.996, p = .042 and OR: 0.817, 95%Cl: 0.689-0.970, p = .021). Increased miR-17 and miR-126 levels were negatively correlated with serum EOPE in PE (r = -.313, p = .020), and increased miR-210 levels were significantly positively correlated with EOPE in PE (r = .285, p = .005). Increased expression of serum miR-17, miR-20a, miR-20b, miR126, and miR-210 were found to be associated with PE, also increased expression of miR-17, miR-20a, and miR-20b were to be predicted with PE, also increased maternal serum miR-17 and miR-126 expressions were negatively correlated and increased miR-210 expression was positively correlated with EOPE in PE women.

Maternal-Infant Factors in Relation to Extracellular Vesicle and Particle miRNA in Prenatal Plasma and in Postpartum Human Milk

MicroRNAs (miRNA) in extracellular vesicles and particles (EVPs) in maternal circulation during pregnancy and in human milk postpartum are hypothesized to facilitate maternal-offspring communication via epigenetic regulation. However, factors influencing maternal EVP miRNA profiles during these two critical developmental windows remain largely unknown. In a pilot study of 54 mother-child dyads in the New Hampshire Birth Cohort Study, we profiled 798 EVP miRNAs, using the NanoString nCounter platform, in paired maternal second-trimester plasma and mature (6-week) milk samples. In adjusted models, total EVP miRNA counts were lower for plasma samples collected in the afternoon compared with the morning (p = 0.024). Infant age at sample collection was inversely associated with total miRNA counts in human milk EVPs (p = 0.040). Milk EVP miRNA counts were also lower among participants who were multiparous after delivery (p = 0.047), had a pre-pregnancy BMI > 25 kg/m2 (p = 0.037), or delivered their baby via cesarean section (p = 0.021). In post hoc analyses, we also identified 22 specific EVP miRNA that were lower among participants who delivered their baby via cesarean section (Q < 0.05). Target genes of delivery mode-associated miRNAs were over-represented in pathways related to satiety signaling in infants (e.g., CCKR signaling) and mammary gland development and lactation (e.g., FGF signaling, EGF receptor signaling). In conclusion, we identified several key factors that may influence maternal EVP miRNA composition during two critical developmental windows, which should be considered in future studies investigating EVP miRNA roles in maternal and child health.

Periconceptional and Prenatal Exposure to Metals and Extracellular Vesicle and Particle miRNAs in Human Milk: A Pilot Study

Human milk is a rich source of microRNAs (miRNAs), which can be transported by extracellular vesicles and particles (EVPs) and are hypothesized to contribute to maternal-offspring communication and child development. Environmental contaminant impacts on EVP miRNAs in human milk are largely unknown. In a pilot study of 54 mother-child pairs from the New Hampshire Birth Cohort Study, we examined relationships between five metals (arsenic, lead, manganese, mercury, and selenium) measured in maternal toenail clippings, reflecting exposures during the periconceptional and prenatal periods, and EVP miRNA levels in human milk. 798 miRNAs were profiled using the NanoString nCounter platform; 200 miRNAs were widely detectable and retained for downstream analyses. Metal-miRNA associations were evaluated using covariate-adjusted robust linear regression models. Arsenic exposure during the periconceptional and prenatal periods was associated with lower total miRNA content in human milk EVPs (PBonferroni < 0.05). When evaluating miRNAs individually, 13 miRNAs were inversely associated with arsenic exposure, two in the periconceptional period and 11 in the prenatal period (PBonferroni < 0.05). Other metal-miRNA associations were not statistically significant after multiple testing correction (PBonferroni ≥ 0.05). Many of the arsenic-associated miRNAs are involved in lactation and have anti-inflammatory properties in the intestine and tumor suppressive functions in breast cells. Our findings raise the possibility that periconceptional and prenatal arsenic exposure may reduce levels of multiple miRNAs in human milk EVPs. However, larger confirmatory studies, which can apply environmental mixture approaches, evaluate potential effect modifiers of these relationships, and examine possible downstream consequences for maternal and child health and breastfeeding outcomes, are needed.

Extracellular vesicles-encapsulated microRNA in mammalian reproduction: A review

Extracellular vesicles (EVs) are nanoscale cell-derived lipid vesicles that participate in cell-cell communication by delivering cargo, including mRNAs, proteins and non-coding RNAs, to recipient cells. MicroRNA (miRNA), a non-coding RNA typically 22 nucleotides long, is crucial for nearly all developmental and pathophysiological processes in mammals by regulating recipient cells gene expression. Infertility is a worldwide health issue that affects 10-15% of couples during their reproductive years. Although assisted reproductive technology (ART) gives infertility couples hope, the failure of ART is mainly unknown. It is well accepted that EVs-encapsulated miRNAs have a role in different reproductive processes, implying that these EVs-encapsulated miRNAs could optimize ART, improve reproductive rate, and treat infertility. As a result, in this review, we describe the present understanding of EVs-encapsulated miRNAs in reproduction regulation.

Systematic review of transcriptome and microRNAome associations with gestational diabetes mellitus

PURPOSE

Gestational diabetes (GDM) is associated with increased risk for preterm birth and related complications for both the pregnant person and newborn. Changes in gene expression have the potential to characterize complex interactions between genetic and behavioral/environmental risk factors for GDM. Our goal was to summarize the state of the science about changes in gene expression and GDM.

DESIGN

The systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

METHODS

PubMed articles about humans, in English, from any date were included if they described mRNA transcriptome or microRNA findings from blood samples in adults with GDM compared with adults without GDM.

RESULTS

Sixteen articles were found representing 1355 adults (n=674 with GDM, n=681 controls) from 12 countries. Three studies reported transcriptome results and thirteen reported microRNA findings. Identified pathways described various aspects of diabetes pathogenesis, including glucose and insulin signaling, regulation, and transport; natural killer cell mediated cytotoxicity; and fatty acid biosynthesis and metabolism. Studies described 135 unique miRNAs that were associated with GDM, of which eight (miR-16-5p, miR-17-5p, miR-20a-5p, miR-29a-3p, miR-195-5p, miR-222-3p, miR-210-3p, and miR-342-3p) were described in 2 or more studies. Findings suggest that miRNA levels vary based on the time in pregnancy when GDM develops, the time point at which they were measured, sex assigned at birth of the offspring, and both the pre-pregnancy and gestational body mass index of the pregnant person.

CONCLUSIONS

The mRNA, miRNA, gene targets, and pathways identified in this review contribute to our understanding of GDM pathogenesis; however, further research is warranted to validate previous findings. In particular, longitudinal repeated-measures designs are needed that control for participant characteristics (e.g., weight), use standardized data collection methods and analysis tools, and are sufficiently powered to detect differences between subgroups. Findings may be used to improve early diagnosis, prevention, medication choice and/or clinical treatment of patients with GDM.

Sex differences in microRNA expression in first and third trimester human placenta†

Maternal and fetal pregnancy outcomes related to placental function vary based on fetal sex, which may be due to sexually dimorphic epigenetic regulation of RNA expression. We identified sexually dimorphic miRNA expression throughout gestation in human placentae. Next-generation sequencing identified miRNA expression profiles in first and third trimester uncomplicated pregnancies using tissue obtained at chorionic villous sampling (n = 113) and parturition (n = 47). Sequencing analysis identified 986 expressed mature miRNAs from female and male placentae at first and third trimester (baseMean>10). Of these, 11 sexually dimorphic (FDR < 0.05) miRNAs were identified in the first and 4 in the third trimester, all upregulated in females, including miR-361-5p, significant in both trimesters. Sex-specific analyses across gestation identified 677 differentially expressed (DE) miRNAs at FDR < 0.05 and baseMean>10, with 508 DE miRNAs in common between female-specific and male-specific analysis (269 upregulated in first trimester, 239 upregulated in third trimester). Of those, miR-4483 had the highest fold changes across gestation. There were 62.5% more female exclusive differences with fold change>2 across gestation than male exclusive (52 miRNAs vs 32 miRNAs), indicating miRNA expression across human gestation is sexually dimorphic. Pathway enrichment analysis identified significant pathways that were differentially regulated in first and third trimester as well as across gestation. This work provides the normative sex dimorphic miRNA atlas in first and third trimester, as well as the sex-independent and sex-specific placenta miRNA atlas across gestation, which may be used to identify biomarkers of placental function and direct functional studies investigating placental sex differences.

Extracellular Vesicles in Blood: Sources, Effects, and Applications

Extracellular vesicles (EVs) are important players for intercellular communication. EVs are secreted by almost all cell types; they can transfer information between nearby or distant cells, and they are highly abundant in body fluids. In this review, we describe the general characteristics of EVs, as well as isolation and characterization approaches. Then, we focus on one of the most relevant sources of EVs: the blood. Indeed, apart from EVs secreted by blood cells, EVs of diverse origins travel in the bloodstream. We present the numerous types of EVs that have been found in circulation. Besides, the implications of blood-derived EVs in both physiological and pathological processes are summarized, highlighting their potential as biomarkers for the diagnosis, treatment monitoring, and prognosis of several diseases, and also as indicators of physiological modifications. Finally, the applications of EVs introduced in the circulatory system are discussed. We describe the use of EVs from distinct origins, naturally produced or engineered, autologous, allogeneic, or even from different species and the effects they have when introduced in circulation. Therefore, the present work provides a comprehensive overview of the components, effects, and applications of EVs in blood.

High-throughput miRNA sequencing of the human placenta: expression throughout gestation

Aim: To understand miRNA changes across gestation in healthy human placentae. This is essential before miRNAs can be used as biomarkers or prognostic indicators during pregnancy. Materials & methods: Using next-generation sequencing, we characterize the normative human placenta miRNome in first (n = 113) and third trimester (n = 47). Results & conclusion: There are 801 miRNAs expressed in both first and third trimester, including 182 with similar expression across gestation (p ≥ 0.05, fold change ≤2) and 180 significantly different (false discovery rate <0.05, fold change >2). Of placenta-specific miRNA clusters, chromosome 14 miRNA cluster decreases across gestation and chromosome 19 miRNA cluster is overall highly expressed. Chromosome 13 clusters are upregulated in first trimester. This work provides a rich atlas of healthy pregnancies to direct functional studies investigating the epigenetic differences in first and third trimester placentae.