Hypermethylation of delta-like homolog 1/maternally expressed gene 3 loci in human umbilical veins: insights into offspring vascular dysfunction born after preeclampsia

Methylation aberrations in partner spermatozoa and impaired expression of imprinted genes in the placentae of early-onset preeclampsia

INTRODUCTION

Disturbed paternal epigenetic status of imprinted genes has been observed in infertility and recurrent spontaneous abortions. Shallow placentation has been associated with early-onset preeclampsia. Hence, the present study aimed to investigate the methylation patterns of imprinted genes involved in placental development, in the spermatozoa of partners of women experiencing preeclampsia.

METHODS

The study involved recruitment of couples into preeclampsia (n = 14) and control (n = 25) groups. Methylation analysis of imprinted gene differentially methylated regions (DMRs) and LINE1 repetitive element was carried out by pyrosequencing in the spermatozoa and placental villi. Global 5 mC levels in the spermatozoa were measured through ELISA. Expression of imprinted genes was quantified in the placental villi by real time qPCR. Association of birth weight with DNA methylation and gene expression was assessed.

RESULTS

KvDMR, PEG3 DMR, PEG10 DMR and DLK1-GTL2 IG-DMR were differentially methylated in the spermatozoa and placental villi of preeclampsia group. Global 5 mC content and LINE1 methylation levels did not differ between the spermatozoa of the two groups. Increased transcript levels of PEG3, IGF2, DLK1, PHLDA2 and CDKN1C were observed in the preeclamptic placental villi. Birth weight showed significant association with KvDMR, PEG10 DMR, DLK1-GTL2 IG-DMR and LINE1 methylation levels in the spermatozoa. DLK1 expression levels showed a negative association with birth weight.

DISCUSSION

The study highlighted the paternal contribution to early-onset preeclampsia, in the form of disrupted sperm DNA methylation patterns at imprinted gene loci. These loci, after further evaluation in future studies, could serve as sperm-based preeclampsia predictive markers, for couples planning pregnancy.

Methylation and expression of imprinted genes in circulating extracellular vesicles from women experiencing early onset preeclampsia

INTRODUCTION

Preeclampsia (PE) is a pregnancy complication marked by high blood pressure, posing risk to maternal and fetal health. "Genomic imprinting", an epigenetic phenomenon regulated by DNA methylation at Differently Methylated Regions (DMR's), influences placental development. Research on circulating extracellular vesicles (EVs) in PE suggests them as potential source for early biomarkers, but methylation status of EV-DNA in Preeclampsia is not reported yet.

METHODS

This study examines the methylation and expression profile of imprinted genes - PEG10, PEG3, MEST, and DLK1 in circulating EVs of 1st and 3rd trimester control and early onset preeclampsia (EOPE) pregnant women (n = 15) using pyrosequencing and qRT-PCR respectively.

RESULTS

In 1st trimester, PEG3 was significantly hypermethylated, whereas no significant methylation changes were noted in PEG10 and MEST in EOPE. In 3rd trimester, significant hypomethylation in PEG10, PEG3 and IGDMR was observed whereas significant hypermethyaltion noted in MEST. mRNA expression of PEG10, PEG3 and DLK1 was not affected in circulating EVs of 1st trimester EOPE. However, in 3rd trimester significant increased expression in PEG10, PEG3 and DLK1 noted. MEST expression was reduced in 3rd trimester EOPE. No correlation was observed between average DNA methylation and gene expression in PEG10 and PEG3 in 1st trimester. However, in 3rd trimester, significant negative correlation was noted in PEG10 (r = -0.426, p = 0.04), PEG3 (r = -0.496, p = 0.01), MEST (r = -0.398, p = 0.03) and DLK1 (r = -0.403, p = 0.03).

DISCUSSION

The results of our study strengthen the potential of circulating EVs from maternal serum as non-invasive indicators of placental pathophysiology, including preeclampsia.

Maternal pregnancy hypertension impairs nitric oxide formation and results in increased arterial blood pressure in first-generation offspring female rats

OBJECTIVES

Maternal endothelial dysfunction in pregnancy hypertension is related to impairment of nitric oxide (NO) formation. However, NO levels and hemodynamic repercussions on the female offspring remain unclear. Therefore, this study hypothesized that maternal pregnancy hypertension reduces circulating NO metabolites and increases arterial blood pressure in first-generation offspring female rats.

STUDY DESIGN

Descendant female rats were distributed in four groups as follows: virgin offspring of normotensive (VN) and hypertensive (VH) mothers and pregnant offspring of normotensive (PN) and hypertensive (PH) mothers. Hemodynamic and biochemical analyses were performed.

MAIN OUTCOME MEASURES

The systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), and body weight were measured. NO metabolites in plasma, NO formation in human umbilical vein endothelial cells (HUVECs) incubated with plasma, and endothelial NO synthase (eNOS) expression in aortas were determined.

RESULTS

Increased SBP, DBP, and reduced HR were found on the 60 days of life in the VH group, whereas the PH group showed increased SBP and HR on pregnancy day 7. All groups showed no differences in body weight gain and eNOS expression. Plasma levels of NO metabolites were increased in the PN compared to the other groups. Increases in the NO formation were greater in HUVECs incubated with plasma from VN and PN groups compared to the VH and PH groups.

CONCLUSIONS

Female virgin and pregnant first-generation offspring rats from hypertensive pregnant mothers may have negative cardiovascular repercussions featured by increases in SBP, and possibly impaired NO formation is involved.

The Molecular Basis of the Augmented Cardiovascular Risk in Offspring of Mothers with Hypertensive Disorders of Pregnancy

The review examines the impact of maternal preeclampsia (PE) on the cardiometabolic and cardiovascular health of offspring. PE, a hypertensive disorder of pregnancy, is responsible for 2 to 8% of pregnancy-related complications. It significantly contributes to adverse outcomes for their infants, affecting the time of birth, the birth weight, and cardiometabolic risk factors such as blood pressure, body mass index (BMI), abdominal obesity, lipid profiles, glucose, and insulin. Exposure to PE in utero predisposes offspring to an increased risk of cardiometabolic diseases (CMD) and cardiovascular diseases (CVD) through mechanisms that are not fully understood. The incidence of CMD and CVD is constantly increasing, whereas CVD is the main cause of morbidity and mortality globally. A complex interplay of genes, environment, and developmental programming is a plausible explanation for the development of endothelial dysfunction, which leads to atherosclerosis and CVD. The underlying molecular mechanisms are angiogenic imbalance, inflammation, alterations in the renin-angiotensin-aldosterone system (RAAS), endothelium-derived components, serotonin dysregulation, oxidative stress, and activation of both the hypothalamic-pituitary-adrenal axis and hypothalamic-pituitary-gonadal axis. Moreover, the potential role of epigenetic factors, such as DNA methylation and microRNAs as mediators of these effects is emphasized, suggesting avenues for future research and therapeutic interventions.

Long-Term Impacts of Preeclampsia on the Cardiovascular System of Mother and Offspring

Preeclampsia is a pregnancy-specific complication that is associated with an increased postpartum risk of cardiovascular disease (CVD) in both women and their offspring, although the underlying mechanisms have yet to be fully elucidated. Nevertheless, differential methylation of cytosine-phosphate-guanosine islands and alterations in the expression of microRNA, associated with an elevated risk of CVD, have been observed in women and their children following preeclampsia. Among this specific population, genetic and epigenetic factors play crucial roles in the development of CVD in later life. A series of biomolecules involved in inflammation, oxidative stress, and angiogenesis may link pregnancy vascular bed disorders in preeclampsia to the pathogenesis of future CVD and thus could be valuable for the prediction and intervention of long-term CVD in women with a history of preeclampsia and their offspring. Here, we present insights into the cardiovascular structure and functional changes of women with a history of preeclampsia and their offspring. With a focus on various underlying mechanisms, the conclusions from this review are expected to provide more potential diagnostics and treatment strategies for clinical practice.

Endothelial microRNAs and long noncoding RNAs in cardiovascular ageing

Atherosclerosis and numerous other cardiovascular diseases develop in an age-dependent manner. The endothelial cells that line the vessel walls play an important role in the development of atherosclerosis. Non-coding RNA like microRNAs and long non-coding RNAs are known to play an important role in endothelial function and are implicated in the disease progression. Here, we summarize several microRNAs and long non-coding RNAs that are known to have an altered expression with endothelial aging and discuss their role in endothelial cell function and senescence. These processes contribute to aging-induced atherosclerosis development and by targeting the non-coding RNAs controlling endothelial cell function and senescence, atherosclerosis can potentially be attenuated.

Short- and Long-Term Outcomes of Preeclampsia in Offspring: Review of the Literature

Preeclampsia is a multisystemic clinical syndrome characterized by the appearance of new-onset hypertension and proteinuria or hypertension and end organ dysfunction even without proteinuria after 20 weeks of pregnancy or postpartum. Residing at the severe end of the spectrum of the hypertensive disorders of pregnancy, preeclampsia occurs in 3 to 8% of pregnancies worldwide and is a major cause of maternal and perinatal morbidity and mortality, accounting for 8-10% of all preterm births. The mechanism whereby preeclampsia increases the risk of the neurodevelopmental, cardiovascular, and metabolic morbidity of the mother's offspring is not well known, but it is possible that the preeclamptic environment induces epigenetic changes that adversely affect developmental plasticity. These developmental changes are crucial for optimal fetal growth and survival but may lead to an increased risk of chronic morbidity in childhood and even later in life. The aim of this review is to summarize both the short- and long-term effects of preeclampsia on offspring based on the current literature.

The multifaceted biology of lncR-Meg3 in cardio-cerebrovascular diseases

Cardio-cerebrovascular disease, related to high mortality and morbidity worldwide, is a type of cardiovascular or cerebrovascular dysfunction involved in various processes. Therefore, it is imperative to conduct additional research into the pathogenesis and new therapeutic targets of cardiovascular and cerebrovascular disorders. Long non-coding RNAs (lncRNAs) have multiple functions and are involved in nearly all cellular biological processes, including translation, transcription, signal transduction, and cell cycle control. LncR-Meg3 is one of them and is becoming increasingly popular. By binding proteins or directly or competitively binding miRNAs, LncR-Meg3 is involved in apoptosis, inflammation, oxidative stress, endoplasmic reticulum stress, epithelial-mesenchymal transition, and other processes. Recent research has shown that LncR-Meg3 is associated with acute myocardial infarction and can be used to diagnose this condition. This article examines the current state of knowledge regarding the expression and regulatory function of LncR-Meg3 in relation to cardiovascular and cerebrovascular diseases. The abnormal expression of LncR-Meg3 can influence neuronal cell death, inflammation, apoptosis, smooth muscle cell proliferation, etc., thereby aggravating or promoting the disease. In addition, we review the bioactive components that target lncR-Meg3 and propose some potential delivery vectors. A comprehensive and in-depth analysis of LncR-Meg3’s role in cardiovascular disease suggests that targeting LncR-Meg3 may be an alternative therapy in the near future, providing new options for slowing the progression of cardiovascular disease.

A novel regulatory mechanism network mediated by lncRNA TUG1 that induces the impairment of spiral artery remodeling in Preeclampsia

Preeclampsia (PE) is associated with maternal and fetal perinatal morbidity and mortality, which brings tremendous suffering and imposes an economic burden worldwide. The failure of uterine spiral artery remodeling may be related to the abnormal function of trophoblasts and lead to the occurrence and progression of PE. Aberrant expression of long non-coding RNAs (lncRNAs) is involved in the failure of uterine spiral artery remodeling. However, the regulation of lncRNA expression in PE is poorly characterized. Here, we reported that hypoxia-induced microRNA (miR)-218 inhibited the expression of lncRNA TUG1 by targeting FOXP1. Further RNA sequencing and mechanism analysis revealed that silencing of TUG1 increased the expression of DNA demethylase TET3 and proliferation-related DUSP family, including DUSP2, DUSP4, and DUSP5, via binding to SUV39H1 in the nucleus. Moreover, TUG1 modulated the DUSP family in vitro through a TET3-mediated epigenetic mechanism. Taken together, our results unmask a new regulatory network mediated by TUG1 as an essential determinant of the pathogenesis of PE, which regulates cell growth and possibly the occurrence and development of other diseases.

Hepatic IGF2/H19 Epigenetic Alteration Induced Glucose Intolerance in Gestational Diabetes Mellitus Offspring via FoxO1 Mediation

OBJECTIVE

The offspring of women with gestational diabetes mellitus (GDM) have a high predisposition to developing type 2 diabetes during childhood and adulthood. The aim of the study was to evaluate how GDM exposure in the second half of pregnancy contributes to hepatic glucose intolerance through a mouse model.

METHODS

By creating a GDM mouse model, we tested glucose and insulin tolerance of offspring by intraperitoneal glucose tolerance test (IPGTT), insulin tolerance test (ITT), and pyruvate tolerance test (PTT). In addition, we checked the expression of genes IGF2/H19, FoxO1, and DNMTs in the mouse liver by RT-qPCR. Pyrosequencing was used to detect the methylation status on IGF2/H19 differentially methylated regions (DMRs). In vitro insulin stimulation experiments were performed to evaluate the effect of different insulin concentrations on HepG2 cells. Moreover, we detect the interaction between FoxO1 and DNMT3A by chromatin immunoprecipitation-quantitative PCR (Chip-qPCR) and knock-down experiments on HepG2 cells.

RESULTS

We found that the first generation of GDM offspring (GDM-F1) exhibited impaired glucose tolerance (IGT) and insulin resistance, with males being disproportionately affected. In addition, the expression of imprinted genes IGF2 and H19 was downregulated in the livers of male mice via hypermethylation of IGF2-DMR0 and IGF2-DMR1. Furthermore, increased expression of transcriptional factor FoxO1 was confirmed to regulate DNMT3A expression, which contributed to abnormal methylation of IGF2/H19 DMRs. Notably, different insulin treatments on HepG2 demonstrated those genetic alterations, suggesting that they might be induced by intrauterine hyperinsulinemia.

CONCLUSION

Our results demonstrated that the intrauterine hyperinsulinemia environment has increased hepatic FoxO1 levels and subsequently increased expression of DNMT3A and epigenetic alterations on IGF2/H19 DMRs. These findings provide potential molecular mechanisms responsible for glucose intolerance and insulin resistance in the first male generation of GDM mice.

Long-Term Consequences of Placental Vascular Pathology on the Maternal and Offspring Cardiovascular Systems

Over the last thirty years, evidence has been accumulating that Hypertensive Disorders of Pregnancy (HDP) and, specifically, Preeclampsia (PE) produce not only long-term effects on the pregnant woman, but have also lasting consequences for the fetus. At the core of these consequences is the phenomenon known as defective deep placentation, being present in virtually every major obstetrical syndrome. The profound placental vascular lesions characteristic of this pathology can induce long-term adverse consequences for the pregnant woman's entire arterial system. In addition, placental growth restriction and function can, in turn, cause a decreased blood supply to the fetus, with long-lasting effects. Women with a history of HDP have an increased risk of Cardiovascular Diseases (CVD) compared with women with normal pregnancies. Specifically, these subjects are at a future higher risk of: Hypertension; Coronary artery disease; Heart failure; Peripheral vascular disease; Cerebrovascular accidents (Stroke); CVD-related mortality. Vascular pathology in pregnancy and CVD may share a common etiology and may have common risk factors, which are unmasked by the "stress" of pregnancy. It is also possible that the future occurrence of a CVD may be the consequence of endothelial dysfunction generated by pregnancy-induced hypertension that persists after delivery. Although biochemical and biophysical markers of PE abound, information on markers for a comparative evaluation in the various groups is still lacking. Long-term consequences for the fetus are an integral part of the theory of a fetal origin of a number of adult diseases, known as the Barker hypothesis. Indeed, intrauterine malnutrition and fetal growth restriction represent significant risk factors for the development of chronic hypertension, diabetes, stroke and death from coronary artery disease in adults. Other factors will also influence the development later in life of hypertension, coronary and myocardial disease; they include parental genetic disposition, epigenetic modifications, endothelial dysfunction, concurrent intrauterine exposures, and the lifestyle of the affected individual.

Disturbance of the Dlk1-Dio3 imprinted domain may underlie placental Dio3 suppression and extracellular thyroid hormone disturbance in placenta-derived JEG-3 cells following decabromodiphenyl ether (BDE209) exposure

Decabromodiphenyl ether (BDE209) has been widely used as a flame retardant in the past four decades, leading to human health consequences, especially neurological impairments. Our previous in vivo studies have suggested that developmental neurotoxicity in offspring may be the result of BDE209-induced placental type III iodothyronine deiodinase (Dio3) disturbance and consequent thyroid hormone (TH) instability. Dio3 is paternally imprinted gene, and its balanced expression is crucial in directing normal development and growth. In this study, we used placenta-derived cells to investigate how BDE209 affected Dio3 expression through interfering imprinting mechanisms in the delta-like homolog 1 (Dlk1)-Dio3 imprinted region. Gene chip analysis and RT-qPCR identified miR409-3p, miR410-5p, miR494-3p, miR668-3p and miR889-5p as potential candidates involved in Dio3 deregulation. The sodium bisulfite-clonal sequencing revealed the BDE209 affect methylation status of two differentially methylated regions (DMRs), intergenic-DMR (IG-DMR) and maternally expressed gene 3-DMR (MEG3-DMR). Our data indicate that placental Dio3 may be a potential molecular target for future study of BDE209 developmental toxicity. In particular, miRNAs, IG-DMR and MEG3-DMR in the Dlk1-Dio3 imprinted locus may be informative in directing studies in TH disturbance and developmental toxicity induced by in utero exposure to environmental persistent organic pollutants (POPs), and those candidate miRNAs may prove to be convenient and noninvasive biomarkers for future large-scale population studies.

Pregnancy Serum DLK1 Concentrations Are Associated With Indices of Insulin Resistance and Secretion

CONTEXT

Delta like noncanonical notch ligand 1 (DLK1) is a paternally expressed imprinted gene that encodes an epidermal growth factor repeat-containing transmembrane protein. A bioactive, truncated DLK1 protein is present in the circulation and has roles in development and metabolism.

OBJECTIVE

We sought to investigate links between maternal pregnancy circulating DLK1 concentrations and: (1) maternal and fetal DLK1 genotypes, (2) maternal insulin resistance and secretion, and (3) offspring size at birth.

PATIENTS, DESIGN, AND SETTING

We measured third-trimester maternal serum DLK1 concentrations and examined their associations with parentally transmitted fetal and maternal DLK1 genotypes, indices of maternal insulin resistance and secretion derived from 75-g oral glucose tolerance tests performed around week 28 of pregnancy, and offspring size at birth in 613 pregnancies from the Cambridge Baby Growth Study.

RESULTS

Maternal DLK1 concentrations were associated with the paternally transmitted fetal DLK1 rs12147008 allele (P = 7.8 × 10-3) but not with maternal rs12147008 genotype (P = 0.4). Maternal DLK1 concentrations were positively associated with maternal prepregnancy body mass index (P = 3.5 × 10-6), and (after adjustment for maternal body mass index) with both maternal fasting insulin resistance (Homeostatic Model Assessment of Insulin Resistance: P = 0.01) and measures of maternal insulin secretion in response to oral glucose (insulinogenic index: P = 1.2 × 10-3; insulin disposition index: P = 0.049). Further positive associations were found with offspring weight (P = 0.02) and head circumference at birth (P = 0.04).

CONCLUSION

These results are consistent with a partial paternal or placental origin for the maternal circulating DLK1 which may lead to increased maternal circulating DLK1 concentrations, stimulation of maternal insulin resistance and compensatory hyperinsulinemia during pregnancy, and the promotion of fetal growth.

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.