Differential placental methylation and expression of VEGF, FLT-1 and KDR genes in human term and preterm preeclampsia

DNA methylation landscape in pregnancy-induced hypertension: progress and challenges

Gestational hypertension (PIH), especially pre-eclampsia (PE), is a common complication of pregnancy. This condition poses significant risks to the health of both the mother and the fetus. Emerging evidence suggests that epigenetic modifications, particularly DNA methylation, may play a role in initiating the earliest pathophysiology of PIH. This article describes the relationship between DNA methylation and placental trophoblast function, genes associated with the placental microenvironment, the placental vascular system, and maternal blood and vascular function, abnormalities of umbilical cord blood and vascular function in the onset and progression of PIH, as well as changes in DNA methylation in the progeny of PIH, in terms of maternal, fetal, and offspring. We also explore the latest research on DNA methylation-based early detection, diagnosis and potential therapeutic strategies for PIH. This will enable the field of DNA methylation research to continue to enhance our understanding of the epigenetic regulation of PIH genes and identify potential therapeutic targets.

Docosahexaenoic acid, eicosapentaenoic acid, arachidonic acid, and neural tube defects in Tunisian population

OBJECTIVE

To determine the effect of maternal status in (plasma and red blood cell) folate, vitamin B12, homocysteine, and vitamin D, as well as their interaction with MTHFR (C677T and A1298C) and MTRR A66G polymorphisms, on maternal plasma docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and arachidonic acid (ARA) levels and the risk of neural tube defects (NTDs).

METHODS

ARA, EPA, and DHA composition was assessed using capillary gas chromatography.

RESULTS

ARA and DHA levels were higher in controls than in case mothers for low plasma folate status. For low red blood cell folate status, DHA levels were higher in controls than in case mothers. For high homocysteine levels, ARA and DHA levels were higher in controls than in case mothers. NTD mothers had lower EPA and DHA levels for low vitamin B12 levels. NTD mothers had lower DHA levels for low vitamin D levels. For low plasma folate status, DHA levels in the MTHFR C677T gene and ARA and EPA levels in MTHFR A1298C gene were different among the three genotypes in case mothers. DHA levels in the MTHFR C677T gene were different among the three genotypes in case mothers for both low and high homocysteine levels. For low vitamin B12 levels, ARA and DHA levels were different among the three genotypes of the MTHFR C677T gene in case mothers. In the MTHFR C677T gene, ARA and DHA levels were different among the three genotypes in case mothers for low vitamin D levels.

CONCLUSIONS

More advanced research is required to verify a suitable biochemical parameter status in relation to the genotypes in pregnant women.

Mechanistic study of pre-eclampsia and macrophage-associated molecular networks: bioinformatics insights from multiple datasets

Background

Pre-eclampsia is a pregnancy-related disorder characterized by hypertension and proteinuria, severely affecting the health and quality of life of patients. However, the molecular mechanism of macrophages in pre-eclampsia is not well understood.

Methods

In this study, the key biomarkers during the development of pre-eclampsia were identified using bioinformatics analysis. The GSE75010 and GSE74341 datasets from the GEO database were obtained and merged for differential analysis. A weighted gene co-expression network analysis (WGCNA) was constructed based on macrophage content, and machine learning methods were employed to identify key genes. Immunoinfiltration analysis completed by the CIBERSORT method, R package "ClusterProfiler" to explore functional enrichment of these intersection genes, and potential drug predictions were conducted using the CMap database. Lastly, independent analysis of protein levels, localization, and quantitative analysis was performed on placental tissues collected from both preeclampsia patients and healthy control groups.

Results

We identified 70 differentially expressed NETs genes and found 367 macrophage-related genes through WGCNA analysis. Machine learning identified three key genes: FNBP1L, NMUR1, and PP14571. These three key genes were significantly associated with immune cell content and enriched in multiple signaling pathways. Specifically, these genes were upregulated in PE patients. These findings establish the expression patterns of three key genes associated with M2 macrophage infiltration, providing potential targets for understanding the pathogenesis and treatment of PE. Additionally, CMap results suggested four potential drugs, including Ttnpb, Doxorubicin, Tyrphostin AG 825, and Tanespimycin, which may have the potential to reverse pre-eclampsia.

Conclusion

Studying the expression levels of three key genes in pre-eclampsia provides valuable insights into the prevention and treatment of this condition. We propose that these genes play a crucial role in regulating the maternal-fetal immune microenvironment in PE patients, and the pathways associated with these genes offer potential avenues for exploring the molecular mechanisms underlying preeclampsia and identifying therapeutic targets. Additionally, by utilizing the Connectivity Map database, we identified drug targets like Ttnpb, Doxorubicin, Tyrphostin AG 825, and Tanespimycin as potential clinical treatments for preeclampsia.

Amino acids analysis reveals serum methionine contributes to diagnosis of the Kawasaki disease in mice and children

BACKGROUND

Kawasaki disease (KD) patients often lack early and definitive diagnosis due to insufficient clinical criteria, whereas biomarkers might accelerate the diagnostic process and treatment.

METHODS

The KD mouse models were established and thirteen amino acids were determined. A total of 551 serum samples were collected including KD patients (n = 134), HCs (n = 223) and KD patients after intravascular immunoglobulin therapy (IVIG, n = 194). A paired analysis of pre- and post-IVIG was employed in 10 KD patients.

RESULTS

The pathological alterations of the aorta, myocardial interstitium and coronary artery vessel were observed in KD mice; the serum levels of methionine in KD mice (n = 40) were markedly altered and negatively correlated with the C-reactive protein levels. Consistent with the mouse model, serum methionine were significantly decreased in KD children, with the relative variation ratio of KD with HCs above 30% and AUROC value of 0.845. Serum methionine were correlated with Z-Score and significantly restored to the normal ranges after KD patient IVIG treatment. Another case-control study with 10 KD patients with IVIG sensitivity and 20 healthy controls validated serum methionine as a biomarker for KD patients with AUROC of 0.86. Elevation of serum DNMT1 activities, but no differences of DNMT3a and DNMT3b, were observed in KD patients when comparing with those in the HCs.

CONCLUSIONS

Our study validated that serum methionine was a potential biomarker for KD, the alteration of which is associated with the activation of DNMT1 in KD patients.

The Relation of VEGFA, VEGFR2, VEGI, and HIF1A Genetic Variants and Their Serum Protein Levels with Breast Cancer in Egyptian Patients

Breast cancer is the most common type of cancer in Egyptian females. Polymorphisms in the angiogenesis pathway have been implicated previously in cancer risk and prognosis. The aim of the current study was to determine whether certain polymorphisms in the genes of vascular endothelial growth factor A (VEGFA), vascular endothelial growth factor receptor 2 (VEGFR2), vascular endothelial growth inhibitor (VEGI), and hypoxia-inducible factor-1α (HIF1A) associated with breast cancer development. The study included 154 breast cancer patients and 132 apparently healthy age-matched females as a control group. VEGFA rs25648 genotyping was performed using (ARMS) PCR technique; while VEGFR2 rs2071559, VEGI rs6478106, and HIF-1α rs11549465 were genotyped by the PCR-RFLP method. Serum levels of VEGF, VEGFR2, VEGI, and HIF1A proteins in breast cancer patients and controls were measured by ELISA. There was a significant association between the VEGFA rs25648 C allele and breast cancer risk (OR 2.5, 95% CI 1.7-3.6, p < 0.001). VEGFA rs25648 C/C genotype was statistically significantly higher in breast cancer patients vs. control (p < 0.001). Participants with the T/T and T/C VEGFR2 rs2071559 genotypes had 5.46 and 5 higher odds, respectively, of having breast cancer than those with the C/C genotype. For the VEGI rs6478106 polymorphism, there was a higher proportion of C allele in breast cancer patients vs. control (p = 0.003). Moreover, the C/C genotype of VEGI rs6478106 was statistically significantly higher in breast cancer patients vs. control (p = 0.001). There was no significant difference in genotypes and allele frequencies of HIF1A rs11549465 polymorphism between breast cancer cases and control individuals (p > 0.05). Serum levels of VEGFA, VEGI, and HIF1A were considerably greater in women with breast cancer than in the control (p < 0.001). In conclusion, the genetic variants VEGFA rs25648, VEGFR2 rs2071559, and VEGI rs6478106 revealed a significant association with increased breast cancer risk in Egyptian patients.

Hypoxia Inducible Factors (HIF1α and HIF3α) are differentially methylated in preeclampsia placentae and are associated with birth outcomes

Preeclampsia is a placental vascular pathology and hypoxia is known to influence placental angiogenesis. Hypoxia Inducible Factors (HIF1α and HIF3α) mediate the response to cellular oxygen concentration and bind to hypoxia response element of target genes. However the mechanism regulating above activity is not well-understood. We investigated if placental DNA methylation (DNAm) and expression of HIF1α and 3α genes are altered and associated with pre-eclampsia, placental weight and birth outcomes. Using a cohort comprising women with preeclampsia [N = 100, delivering at term (N = 43) and preterm (N = 57)] and normotensive controls (N = 100), we analysed DNAm in HIF1α and 3α, and their mRNA expression in placentae, employing pyrosequencing and quantitative real-time PCR, respectively. We observed significant hypermethylation at cg22891070 of HIF3α in preeclampsia placentae compared to controls (β = 1.5%, p = 0.04). CpG8 in the promoter region of HIF1α, showed marginally significant hypomethylation in preterm preeclampsia compared to controls (β = - 0.15%, p = 0.055). HIF1α expression was significantly lower in preterm preeclampsia compared to controls (mean ± SE = 10.16 ± 2.00 vs 4.25 ± 0.90, p = 0.04). Further, DNAm in HIF1α promoter region was negatively associated with its expression levels (β =  - 0.165, p = 0.024). Several CpGs in HIF1α were negatively associated with placental weight and birth outcomes including birth weight (β range =  - 0.224-0.300) and birth length [β range =  - 0.248 to - 0.301 (p < 0.05 for all)]. Overall, we demonstrate altered DNAm in HIF1α and HIF3α in preeclampsia placentae, also associated with various birth outcomes. Correlation of DNAm in HIF1α and its expression suggests a possible role in the pathogenesis of pre-eclampsia. Further investigations on interactions between HIF1α and HIF3α in preeclampsia would be interesting.

Vascular Distribution and Expression Patterns of Angiogenic Factors in Caruncle during the Early Stage of Pregnancy in Goats (Capra hircus)

The placenta is a temporary maternal−fetal organ, and its maternal placenta (caruncle) is essential for fetal growth and development. The exchange function of the placenta requires vascular development (angiogenesis). However, the angiogenesis of the caruncle is poorly understood in goats during the early stage of pregnancy. Here, we investigated the vascular distribution, mRNA expression of major angiogenic factors, and the methylation levels of ANGPT2 in the goat caruncle. It showed that CAD (capillary area density), CSD (capillary surface density), and APC (area per capillary) increased gradually, while CND (capillary number density) showed an insignificant change, probably due to the variability between animals. The proportion of proliferating cells was observed to be very high (>26%) and increased (p < 0.002) approximately 2-fold from day 20 to 60 of pregnancy. Furthermore, the expression patterns of major angiogenic factors changed during the early stage of pregnancy. Interestingly, we discovered an absolute correlation between the mRNA for ANGPT2, TEK, FGF2, and vascular distribution. Subsequently, we evaluated the DNA methylation of ANGPT2, where we found that mean methylation was negatively correlated with CAD. The methylation at the CpG sites, such as CpG 4/18, CpG 9.10.11, and CpG 15, showed significant changes during the early stage of pregnancy. Thus, our findings suggest that the methylation of ANGPT2 may be involved in the regulation of caruncle angiogenesis during the early stage of pregnancy.

DNA methylation in diabetic retinopathy: pathogenetic role and potential therapeutic targets

Background

Diabetic retinopathy (DR), a specific neuron-vascular complication of diabetes, is a major cause of vision loss among middle-aged people worldwide, and the number of DR patients will increase with the increasing incidence of diabetes. At present, it is limited in difficult detection in the early stages, limited treatment and unsatisfactory treatment effects in the advanced stages.

Main body

The pathogenesis of DR is complicated and involves epigenetic modifications, oxidative stress, inflammation and neovascularization. These factors influence each other and jointly promote the development of DR. DNA methylation is the most studied epigenetic modification, which has been a key role in the regulation of gene expression and the occurrence and development of DR. Thus, this review investigates the relationship between DNA methylation and other complex pathological processes in the development of DR. From the perspective of DNA methylation, this review provides basic insights into potential biomarkers for diagnosis, preventable risk factors, and novel targets for treatment.

Conclusion

DNA methylation plays an indispensable role in DR and may serve as a prospective biomarker of this blinding disease in its relatively early stages. In combination with inhibitors of DNA methyltransferases can be a potential approach to delay or even prevent patients from getting advanced stages of DR.

Vascular endothelial growth factor and its receptors regulation in gestational diabetes mellitus and eclampsia

Background

An imbalance in the expression of vascular endothelial growth factor (VEGF) and its receptor (VEGF-R) during pregnancy plays an important role in the pathogenesis of gestational diabetes mellitus (GDM) and eclampsia. VEGF and its receptors change during the regulation of blood vessels as a result of risk factors such as familial genetics. These modifications include loss of original balance of serological indicators, upregulation or downregulation of growth factor indicators, and changes in the placenta, kidney, liver and other organs to varying degrees of damage. This has an impact on both the pregnant woman's and the fetus's health.

Main body

This paper summarizes the mechanisms of unbalanced VEGF and receptor expression based on data from relevant literature on GDM and eclampsia. An Imbalance in VEGF and its binding receptor is often associated with the occurrence of multiple pregnancy disorders. In recent years, researchers have focused on the potential role of VEGF and its receptors in the development of GDM and eclampsia.

Conclusion

This paper summarizes the different VEGF subtypes and their binding receptors, as well as mechanisms that cause GDM and eclampsia, in order to provide valuable data to inform monitoring, diagnosis, and prognosis.

Attenuation of placental pyruvate kinase M2 promotes oxidative imbalance and enhances inflammatory- apoptosis cross talk in rats with hyperhomocysteinemia associated pregnancy loss.. [DOI: 10.21203/rs.3.rs-1997950/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

10-15% of clinically recognized pregnancies end in miscarriage. Hyperhomocysteinemia in pregnant women has been associated with deep venous thrombosis, recurrent miscarriage, preeclampsia to name a few. Impaired placental function due to overt oxidative stress is one of the key mechanisms in development of pregnancy loss. Paucity of pathway–based microarray approach in embryonic–endometrial communication warrants elucidation of distinct profile of miRNAs in hyperhomocysteinemia-associated pregnancy loss (HAPL). Hyperhomocysteinemia was induced at a dose of 100mg/kg body-weight/day for D1-D18 of pregnancy. Placental histology by haematoxylin-eosin staining documented thrombus with reduced area of spongiotropoblasts in chorionic plate vessel. Placental mRNA was subjected to microarray analysis followed by pathway-analysis using Ingenuity Pathway Analysis (IPA). Genes involved in reproductive physiology, inflammatory pathways, immune responses, homocysteine metabolism, glucose metabolism, and oxidative stress were differentially expressed in HAPL. 21 pathways documented by IPA, were skewed to 10 by recursive feature elimination highlighting possible deregulation/s. Expression/s was re-confirmed by quantitative real- time PCR (qRT-PCR), western blot and flow cytometric analysis (FACS). Nine priori molecules (PKM2, AKT, PI3K, NF-κB, COX-2, sflt-1, HIF-1α, bax, caspase 9) were specifically modulated in HAPL as demonstrated by protein and mRNA expression. A parallel increase in insulin signaling (PI3K+,AKT+), inflammation (COX2+,NF-κB+), hypoxia (sflt-1+,HIF-1α+), apoptosis (bax+,caspase9+) with concomitant decrease in pyruvate kinase M2 in hyperhomocysteinemic placental cells by FACS with CD56, a marker for pregnancy loss was documented. The findings provide evidence that an oxidative stress-mediated placental damage perhaps represents the pathogenesis of HAPL, which may explore pathway-based therapeutic options for recurrent miscarriage.10–15% of clinically recognized pregnancies end in miscarriage. Hyperhomocysteinemia in pregnant women has been associated with deep venous thrombosis, recurrent miscarriage, preeclampsia to name a few. Impaired placental function due to overt oxidative stress is one of the key mechanisms in development of pregnancy loss. Paucity of pathway–based microarray approach in embryonic–endometrial communication warrants elucidation of distinct profile of miRNAs in hyperhomocysteinemia-associated pregnancy loss (HAPL). Hyperhomocysteinemia was induced at a dose of 100mg/kg body-weight/day for D1-D18 of pregnancy. Placental histology by haematoxylin-eosin staining documented thrombus with reduced area of spongiotropoblasts in chorionic plate vessel. Placental mRNA was subjected to microarray analysis followed by pathway-analysis using Ingenuity Pathway Analysis (IPA). Genes involved in reproductive physiology, inflammatory pathways, immune responses, homocysteine metabolism, glucose metabolism, and oxidative stress were differentially expressed in HAPL. 21 pathways documented by IPA, were skewed to 10 by recursive feature elimination highlighting possible deregulation/s. Expression/s was re-confirmed by quantitative real- time PCR (qRT-PCR), western blot and flow cytometric analysis (FACS). Nine priori molecules (PKM2, AKT, PI3K, NF-κB, COX-2, sflt-1, HIF-1α, bax, caspase 9) were specifically modulated in HAPL as demonstrated by protein and mRNA expression. A parallel increase in insulin signaling (PI3K+,AKT+), inflammation (COX2+,NF-κB+), hypoxia (sflt-1+,HIF-1α+), apoptosis (bax+,caspase9+) with concomitant decrease in pyruvate kinase M2 in hyperhomocysteinemic placental cells by FACS with CD56, a marker for pregnancy loss was documented. The findings provide evidence that an oxidative stress-mediated placental damage perhaps represents the pathogenesis of HAPL, which may explore pathway-based therapeutic options for recurrent miscarriage.

Integrative analysis of circulating microRNAs and the placental transcriptome in recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is a major type of pathological pregnancy that still lacks reliable early diagnosis and effective treatment. The placenta is critical to fetal development and pregnancy success because it participates in critical processes such as early embryo implantation, vascular remodeling, and immunological tolerance. RPL is associated with abnormalities in the biological behavior of placental villous trophoblasts, resulting in aberrant placental function. MicroRNAs (miRNAs) are increasingly being recognized as essential regulators of placental development, as well as potential biomarkers. In this study, plasma miRNAs and placental messenger RNAs (mRNAs) from RPL patients and normal pregnant (NP) controls were sequenced and analyzed. Compared to those in NP controls, 108 circulating miRNAs and 1199 placental mRNAs were differentially expressed in RPL samples. A total of 140 overlapping genes (overlapping between plasma miRNA target genes and actual placental disorder genes) were identified, and functional enrichment analysis showed that these genes were mainly related to cell proliferation, angiogenesis, and cell migration. The regulatory network among miRNAs, overlapping genes, and downstream biological processes was analyzed by protein–protein interactions and Cytoscape. Moreover, enriched mRNAs, which were predictive targets of the differentially expressed plasma miRNAs miR-766-5p, miR-1285-3p, and miR-520a-3p, were accordingly altered in the placenta. These results suggest that circulating miRNAs may be involved in the pathogenesis of RPL and are potential noninvasive biomarkers for RPL.

Fetal hyperhomocysteinemia is associated with placental inflammation and early breakdown of maternal-fetal tolerance in Pre-term birth

PROBLEM

Hyperhomocysteinemia (hypHcy) due to impaired folate metabolism is shown to be a risk factor for preterm birth (PTB) and low birth weight (LBW) in mothers. However, the relationship of fetal hypHcy with adverse pregnancy outcomes is under-represented. The present study aims to investigate the association of fetal hypHcy with oxidative stress and placental inflammation that can contribute to an early breakdown of maternal-fetal tolerance in pre-term birth (PTB).

METHODS

Cord blood and placenta tissue were collected from PTB and term infant group. Levels of homocysteine, folic acid, vitamin B12 and oxidative stress markers (MDA, T-AOC, 8-OHdG) were measured in cord blood serum using ELISA and respective standard assay kits. Relative expression of candidate genes (TNF-α, IL-6, IL1-β, VEGF-A, MMP2 and MMP9) was also checked using RT-PCR and immunoblotting/immunohistochemistry.

RESULTS

PTB infants showed significantly higher levels of homocysteine (p = 0.02) and lower levels of vitamin B12 (p = 0.005) as compared to term infants. We also found that PTB infants with hypHcy had lower T-AOC (p = 0.003) and higher MDA (p = 0.04) levels as compared to term infants with normal homocysteine levels. The mRNA and protein levels of TNF-α, VEGF-A, MMP2 and MMP9 were significantly higher in hypHcy PTB infants.

CONCLUSION

Our results show that fetal hypHcy is associated with oxidative stress and an increase in inflammatory markers in the placenta. Thus, in conclusion, our study demonstrates that fetal hypHcy during pregnancy is a potential risk factor that may initiate an early breakdown of uterine quiescence due to activation of inflammatory processes leading to PTB. This article is protected by copyright. All rights reserved.

Analyses of selected tumour-associated factors expression in normotensive and preeclamptic placenta

INTRODUCTION

Human placenta is often considered a controlled-tumour because of shared properties such as invasion and angiogenesis. We assessed the status of a few selected tumour-associated factors (TAFs) in late onset pre-eclamptic (PE) and normotensive (NT) placentae, to understand their involvement in trophoblast invasion. These molecules include aldehyde dehydrogenase (ALDH3A1), aurora kinases (AURK-A/C), platelet derived growth factor receptor-α (PDGFRα), jagged-1 (JAG1) and twist related protein-1 (TWIST1).

METHODS

The expression of TAF was compared in 13 NT and 11 PE (late onset) placentae using immunoblotting/immunohistochemistry. We then used a novel spheroidal cell model developed from transformed human first trimester trophoblast cell lines HTR8/SVneo and TEV-1 to determine the expression and localization of these six factors during invasion. We also compared the expression of these TAFs during migration and invasion.

RESULTS

Our results suggest that expressions of ALDH3A1, AURK-A, PDGFRα, and TWIST1 are significantly upregulated in PE placentae (p < 0.05) when compared to NT placentae, whereas AURK-C and JAG1 are down-regulated (p < 0.05). The protein expression pattern of all the six factors were found to be similar in spheroids in comparison to their parental counterparts. The invasive potential of the spheroids was also enhanced when compared with the parental cells.

DISCUSSION

Collectively, data from our present study suggests that these TAFs are involved in placental invasion and their altered expressions may be regarded as a compensatory mechanism against reduced invasion.

Differential expression of Hsa-miR-517a/b in placental tissue may contribute to the pathogenesis of preeclampsia

Objective:

Preeclampsia (PE) is a pregnancy hypertensive disorder that affects both maternal and fetal health. Many studies have investigated possible mechanisms in the pathogenesis of PE although the role of the placenta is undeniable. Evaluation of placental-specific microRNAs may provide additional data about the pathogenic mechanism of PE. This study compared the expression levels of Hsa-miR-517a/b in placental tissues obtained from PE patients and healthy controls.

Material and Methods:

One hundred tissues were obtained from fetal and maternal sides of the placenta of PE patients and healthy controls. Expression analysis was performed using quantitative real-time polymerase chain reaction.

Results:

Hsa-miR-517a/b level was significantly decreased in PE compared to controls (expression ratio: 0.40; p=0.007). Down-regulation of Hsa-miR-517a/b was also detected in fetal-side placental samples when compared to maternal-side in PE (expression ratio: 0.33; p=0.04). Furthermore, decreased expression of Hsa-miR-517a/b was detected in fetal-side tissue from PE cases compared to fetal-side samples from healthy pregnancies (expression ratio: 0.36; p=0.03). In maternal-side placental samples the expression level did not differ between PE and healthy pregnancies (p=0.1).

Conclusion:

These results demonstrate a differential expression of Hsa-miR-517a/b within placentas in pregnancies affected by PE and between placentas from PE and healthy pregnancies. Further studies are required to investigate a possible role for Hsa-miR-517a/b in the pathogenesis of PE.

Altered neurodevelopmental DNA methylation status after fetal growth restriction with brain-sparing

It is under debate how preferential perfusion of the brain (brain-sparing) in fetal growth restriction (FGR) relates to long-term neurodevelopmental outcome. Epigenetic modification of neurotrophic genes by altered fetal oxygenation may be involved. To explore this theory, we performed a follow-up study of 21 FGR children, in whom we prospectively measured the prenatal cerebroplacental ratio (CPR) with Doppler sonography. At 4 years of age, we tested their neurodevelopmental outcome using the Wechsler Preschool and Primary Scale of Intelligence, the Child Behavior Checklist, and the Behavior Rating Inventory of Executive Function. In addition, we collected their buccal DNA to determine the methylation status at predefined genetic regions within the genes hypoxia-inducible factor-1 alpha (HIF1A), vascular endothelial growth factor A (VEGFA), erythropoietin (EPO), EPO-receptor (EPOR), brain-derived neurotrophic factor (BDNF), and neurotrophic tyrosine kinase, receptor, type 2 (NTRK2) by pyrosequencing. We found that FGR children with fetal brain-sparing (CPR <1, n = 8) demonstrated a trend (0.05 < p < 0.1) toward hypermethylation of HIF1A and VEGFA at their hypoxia-response element (HRE) compared with FGR children without fetal brain-sparing. Moreover, in cases with fetal brain-sparing, we observed statistically significant hypermethylation at a binding site for cyclic adenosine monophophate response element binding protein (CREB) of BDNF promoter exon 4 and hypomethylation at an HRE located within the NTRK2 promoter (both p <0.05). Hypermethylation of VEGFA was associated with a poorer Performance Intelligence Quotient, while hypermethylation of BDNF was associated with better inhibitory self-control (both p <0.05). These results led us to formulate the hypothesis that early oxygen-dependent epigenetic alterations due to hemodynamic alterations in FGR may be associated with altered neurodevelopmental outcome in later life. We recommend further studies to test this hypothesis.

Vegfa promoter gene hypermethylation at HIF1α binding site is an early contributor to CKD progression after renal ischemia

Chronic hypoxia is a major contributor to Chronic Kidney Disease (CKD) after Acute Kidney Injury (AKI). However, the temporal relation between the acute insult and maladaptive renal response to hypoxia remains unclear. In this study, we analyzed the time-course of renal hemodynamics, oxidative stress, inflammation, and fibrosis, as well as epigenetic modifications, with focus on HIF1α/VEGF signaling, in the AKI to CKD transition. Sham-operated, right nephrectomy (UNx), and UNx plus renal ischemia (IR + UNx) groups of rats were included and studied at 1, 2, 3, or 4 months. The IR + UNx group developed CKD characterized by progressive proteinuria, renal dysfunction, tubular proliferation, and fibrosis. At first month post-ischemia, there was a twofold significant increase in oxidative stress and reduction in global DNA methylation that was maintained throughout the study. Hif1α and Vegfa expression were depressed in the first and second-months post-ischemia, and then Hif1α but not Vegfa expression was recovered. Interestingly, hypermethylation of the Vegfa promoter gene at the HIF1α binding site was found, since early stages of the CKD progression. Our findings suggest that renal hypoperfusion, inefficient hypoxic response, increased oxidative stress, DNA hypomethylation, and, Vegfa promoter gene hypermethylation at HIF1α binding site, are early determinants of AKI-to-CKD transition.

Pregnancy, delivery, and neonatal outcomes among women with irritable bowel syndrome (IBS) an evaluation of over 9 million deliveries

OBJECTIVE

Evaluate the associations between irritable bowel syndrome (IBS) and pregnancy, delivery, and neonatal outcomes, using a population database cohort.

METHODS

We conducted a retrospective analysis utilizing the Health Care Cost and Utilization Project-Nationwide Inpatient Sample database over 11 years from 2004 to 2014. A delivery cohort was created using ICD-9 codes. ICD-9 code 564.1 was used to extract the cases of IBS. Pregnant women with IBS (study group) were compared to pregnant women without IBS (control). A multivariate logistic regression model was used to adjust for statistically significant variables (p value <.05).

RESULTS

There were a total of 9,096,788 deliveries during the study period. Of those, 8962 pregnant women were found to have IBS. The prevalence of IBS increased from 47.96 to 172.68 per 100,000 women during the study period. Compared to the control group, women with IBS were more likely to be Caucasian, older, have higher incomes and private insurance plans (p < .0001, in all cases). In addition, they were more likely to be obese, smokers, hypertensive, IVF pregnancies, have multiple gestations, thyroid disorders, chronic interstitial cystitis, fibromyalgia and have psychiatric disorders (p < .0001 in all cases). Women with IBS were more likely to experience pregnancy-induced hypertension (aOR 1.11, 95% CI 1.02-1.21), preeclampsia (aOR 1.23, 95% CI 1.09-1.38), deep venous thrombosis (aOR 2.26, 95% CI 1.12-4.57), and gestational diabetes (aOR 1.1, 95% CI 1.002-1.22) compared to the non-IBS group. Congenital anomalies were encountered in 1.7% of the IBS group compared to 0.4% in the control group (aOR 2.57, 95% CI 2.13-3.09).

CONCLUSION

When controlling for confounding effects, IBS is associated with an increased risk for preeclampsia, DVT and increased risk for congenital malformation.

Angiogenic markers predict kidney injury and obstetric complications in women with preeclampsia and pregnancy-related acute kidney injury

Pregnancy-related acute kidney injury (PRAKI) particularly on top of preeclampsia (PE) represents a major cause of maternal and fetal morbidity and mortality. Reliable diagnostic tools are needed to further evaluate the diagnosis and prognosis of PRAKI. Our objective was to study the diagnostic and prognostic value of angiogenic markers (e.g., stromal cell-derived factor 1 (SDF-1), vascular endothelial growth factor (VEGF), alarmins as uric acid) in women with PE and PRAKI. This prospective study included three groups; PRAKI, PE patients, and healthy controls that were compared regarding serum levels of the studied markers correlated to renal, maternal, and fetal outcomes. SDF-1, VEGF, and uric acid levels were significantly different between the three included groups and predicted PRAKI diagnosis. Patients with hemolysis, elevated liver enzymes, and low platelet (HELLP) syndrome exhibited the highest titers of SDF-1 and VEGF. A positive correlation was found between SDF-1 and renal recovery. Conclusively, serum assays of SDF-1, VEGF, and uric acid may add a diagnostic value in PRAKI and PE.

Placental growth factor and Fms related tyrosine kinase-1 are hypomethylated in preeclampsia placentae

Aim: This study aims to examine the DNA methylation (DNAm) and expression patterns of genes associated with placental angiogenesis in preeclampsia. Materials & methods: DNAm and expression were examined in normotensive (n = 100) and preeclampsia (n = 100) women using pyrosequencing and quantitative real-time PCR respectively. Results: Hypomethylation at several CpGs was observed in PlGF and FLT-1 in women with preeclampsia compared to normotensive controls. PlGF expression was lower in women with preeclampsia while FLT-1 expression was comparable. DNAm at various CpGs was negatively correlated with expression in both the genes and were associated with maternal blood pressure and birth outcomes. Conclusion: DNAm and expression of angiogenic factors in placentae are differentially regulated in preeclampsia and influence birth outcomes.

Role of maternal nutrition and oxidative stress in placental telomere attrition in women with preeclampsia

Background:Maternal nutrition influences the growth and development of the fetus and influences pregnancy outcome. We have earlier demonstrated altered maternal nutrition and increased oxidative stress in women with preeclampsia. Oxidative stress is known to be associated with reduced telomere length and short telomere aggregates. Increased telomere attrition leads to increased cellular senescence and tissue ageing. Methods:The present review focuses on the role of maternal nutrition and oxidative stress in telomere attrition in preeclampsia. Results and Conclusion:Future studies need to examine the association between maternal nutritional status in early pregnancy, oxidative stress and telomere attrition in preeclampsia.

DNA Methylation of TLR4, VEGFA, and DEFA5 Is Associated With Necrotizing Enterocolitis in Preterm Infants

Background: Epigenetic changes, such as DNA methylation, may contribute to an increased susceptibility for developing necrotizing enterocolitis (NEC) in preterm infants. We assessed DNA methylation in five NEC-associated genes, selected from literature: EPO, VEGFA, ENOS, DEFA5, and TLR4 in infants with NEC and controls. Methods: Observational cohort study including 24 preterm infants who developed NEC (≥Bell Stage IIA) and 45 matched controls. DNA was isolated from stool samples and methylation measured using pyrosequencing. We investigated differences in methylation prior to NEC compared with controls. Next, in NEC infants, we investigated methylation patterns long before, a short time before NEC onset, and after NEC. Results: Prior to NEC, only TLR4 CpG 2 methylation was increased in NEC infants (median = 75.4%, IQR = 71.3-83.8%) versus controls (median = 69.0%, IQR = 64.5-77.4%, p = 0.025). In NEC infants, VEGFA CpG 3 methylation was 0.8% long before NEC, increasing to 1.8% a short time before NEC and 2.0% after NEC (p = 0.011; p = 0.021, respectively). A similar pattern was found in DEFA5 CpG 1, which increased from 75.4 to 81.4% and remained 85.3% (p = 0.027; p = 0.019, respectively). These changes were not present for EPO, ENOS, and TLR4. Conclusion: Epigenetic changes of TLR4, VEGFA, and DEFA5 are present in NEC infants and can differ in relation to the time of NEC onset. Differences in DNA methylation of TLR4, VEGFA, and DEFA5 may influence gene expression and increase the risk for developing NEC. This study also demonstrates the use of human DNA extraction from stool samples as a novel non-invasive method for exploring the bowel of preterm infants and which can also be used for necrotizing enterocolitis patients.

Prenatal vitamin D supplementation reduces blood pressure and improves placental angiogenesis in an animal model of preeclampsia

BACKGROUND

Preeclampsia (PE), a pregnancy complication, is characterized by abnormal placental angiogenesis. The current study examines the effect of vitamin D deficiency/supplementation on pregnancy outcome and placental angiogenesis using an animal model of PE.

METHODS

Pregnant Wistar rats were divided into four groups: Control; PE; Vitamin D deficient with PE (VDD-PE) and Vitamin D supplemented with PE (VDS-PE). PE was induced by administering l-nitroarginine methyl ester (l-NAME) at the dose of 50 mg per kg body weight per day from day 14 to day 19 gestation in all the 4 groups. During the pre-pregnancy and pregnancy period, the rats from the Control and PE groups were fed a control diet, the VDD-PE group received a vitamin D deficient diet and the VDS-PE group received a vitamin D supplemented diet. Dams were sacrificed at d20 of gestation.

RESULTS

l-NAME administration increased systolic as well as diastolic blood pressure in both PE and VDD-PE groups as compared to the control (p < 0.01). Vitamin D supplementation was beneficial in reducing the blood pressure. Vitamin D deficiency also lowered the placental protein levels of pro-angiogenic proteins VEGF and Flt-1 (p < 0.05 and p < 0.01, respectively), while the levels of these proteins in the VDS-PE group were similar to those in the control group. Vitamin D status did not influence the levels of PlGF and Hif1α.

CONCLUSION

A low dose vitamin D supplementation given from pre-pregnancy and throughout pregnancy was beneficial in reducing the blood pressure and normalizing the placental levels of VEGF and Flt-1. This has implications for reducing the severity of preeclampsia.

Epigenome-wide DNA methylation profiling of preeclamptic placenta according to severe features

Background

Preeclampsia (PE) is an obstetric disorder with significant morbidities for both the mother and fetus possibly caused by a failure of the placental trophoblast invasion. However, its pathophysiology largely remains unclear. Here, we performed DNA methylation profiling to determine whether differential patterns of DNA methylation correlate with PE and severe features of PE.

Materials and methods

We extracted DNA from placental tissues of 13 normal, five PE, and eight PE pregnant women with severe features. Genome-wide DNA methylation analysis was performed using the Illumina HumanMethylation 850K BeadChip. New functional annotations of differentially methylated CpGs (DMCs) in PE were predicted using bioinformatics tools.

Results

Significant differences were evident for 398 DMCs, including 243 DMCs in PE and 155 DMCs in PE with severe features, compared with normal placental tissues. Of these, 12 hypermethylated DMCs and three hypomethylated DMCs were observed in both PE groups, thus were independent from severe features. Three hundred seventy-nine DMCs were identified by the presence or absence of severe features. Two hundred genes containing these DMCs were associated with developmental processes and cell morphogenesis. These genes were significantly associated with various PE complications such as disease susceptibility, viral infections, immune system diseases, endocrine disturbance, seizures, hematologic diseases, and thyroid diseases.

Conclusions

This is the first study to investigate the genome-scale DNA methylation profiles of PE placentas according to severe features. The epigenetic variation in the placentas probably resulted in altered developmental processes and immune dysregulation, contributing to PE. This study provides basic information to refine the clinical and pathological mechanisms of the severe features in placenta-mediated PE.

Systematic review supports the role of DNA methylation in the pathophysiology of preeclampsia: a call for analytical and methodological standardization

BACKGROUND

Studies have recently examined the role of epigenetic mechanisms in preeclampsia pathophysiology. One commonly examined epigenetic process is DNA methylation. This heritable epigenetic marker is involved in many important cellular functions. The aim of this study was to establish the association between DNA methylation and preeclampsia and to critically appraise the roles of major study characteristics that can significantly impact the association between DNA methylation and preeclampsia.

MAIN BODY

A systematic review was performed by searching PubMed, Web of Science, and EMBASE for original research articles published over time, until May 31, 2019 in English. Eligible studies compared DNA methylation levels in pregnant women with vs. without preeclampsia. Ninety articles were included. Epigenome-wide studies identified hundreds of differentially methylated places/regions in preeclamptic patients. Hypomethylation was the predominant finding in studies analyzing placental tissue (14/19), while hypermethylation was detected in three studies that analyzed maternal white blood cells (3/3). In candidate gene studies, methylation alterations for a number of genes were found to be associated with preeclampsia. A greater number of differentially methylated genes was found when analyzing more severe preeclampsia (70/82), compared to studies analyzing less severe preeclampsia vs. controls (13/27). A high degree of heterogeneity existed among the studies in terms of methodological study characteristics including design (study design, definition of preeclampsia, control group, sample size, confounders), implementation (biological sample, DNA methylation method, purification of DNA extraction, and validation of methylation), analysis (analytical method, batch effect, genotyping, and gene expression), and data presentation (methylation quantification measure, measure of variability, reporting). Based on the results of this review, we provide recommendations for study design and analytical approach for further studies.

CONCLUSIONS

The findings from this review support the role of DNA methylation in the pathophysiology of preeclampsia. Establishing field-wide methodological and analytical standards may increase value and reduce waste, allowing researchers to gain additional insights into the role of DNA methylation in the pathophysiology of preeclampsia.

Region-specific changes in the mRNA and protein expression of LCPUFA biosynthesis enzymes and transporters in the placentae of women with preeclampsia

The biosynthesis and transport of long chain polyunsaturated fatty acids (LCPUFA) require the activity of fatty acid desaturase (FADS) enzymes, fatty acid transport proteins (FATP) and fatty acid binding proteins (FABP). In a previous study we have demonstrated region-specific changes in the LCPUFA levels in preeclampsia (PE) as compared to the normotensive control (NC) placentae.

AIM

To understand the region-specific changes in the mRNA levels and protein expression of biosynthesis enzymes and transporters of LCPUFA in PE and NC placentae.

METHODS

In this cross-sectional study, 20 NC women and 44 women with PE (23 term (TPE) and 21 preterm PE (PTPE)) were recruited. The samples were collected from four regions of the placentae considering cord insertion as the center (CM, central maternal/basal; CF, central fetal/chorionic; PM, peripheral maternal/basal and PF, peripheral fetal/chorionic). The mRNA levels were estimated using qRT-PCR. Statistical analysis was done using both post hoc least significant difference (LSD) test and Benjamini Hochberg correction in the analysis of covariance. Preliminarily, localization and expression of proteins were studied by immunohistochemistry (n = 3/group).

RESULTS

The mRNA levels of FADS1, FADS2 and FATP1 were lower in the central regions (CM and CF) of the PE placentae (both TPE and PTPE) as compared to NC. These differences in the mRNA levels were observed by the LSD test and were not significant after the Benjamini Hochberg correction. Preliminary findings of IHC indicate that the protein expression of FADS1 and FATP4 was higher in the basal regions (CM and PM) of the PE placentae as compared to NC. FADS1, FADS2 and FATP4 proteins were localized in the syncytiotrophoblasts, cytotrophoblasts, mesenchymal cells, endothelial cells of the fetal capillaries and extravillous trophoblasts of the placenta.

CONCLUSION

FADS enzymes are detected in the placentae of Indian women. In PE placentae, there are region-specific alterations in the mRNA and protein levels of LCPUFA biosynthesis enzymes (FADS1 and FADS2) and transporters (FATP1, FATP4 and FABP3) as compared to term NC. These changes were more pronounced toward the basal side and region around the cord insertion.

Differential placental methylation in preeclampsia, preterm and term pregnancies

INTRODUCTION

Preeclampsia (PE) is one of the leading causes of maternal mortality and morbidity worldwide. Recently, the role of epigenetic modifications in preeclampsia has been a focus of research. This study was to identified genes or pathways that may be associated with PE, and discuss whether the changes in the methylation level of these genes is related to the pathogenesis of PE.

METHODS

The methylation levels of placental tissues between PE (n = 4), preterm birth (PB, n = 4) and term birth (TB, n = 4) were detected by Illumina Infinium HumanMethylation850 K BeadChip. Pyrosequencing and qRT-PCR were used to validated the methylation and expression levels of the genes with the most significant differences.

RESULTS

The global methylation levels of placenta tissues in PE and PB were both higher compared to TB. After eliminated the effect of gestational age, there were 808 gene probes differentially methylated in PE compared to PB. We found 137 genes with 130 genes hypermethylated and 7 genes hypomethylated. CMIP, BLCAP and MICA genes were with the most significant differential methylation. The expression level of CMIP and BLCAP were both negatively correlated to the methylation levels, while the expression level of MICA was not related to its methylation levels.

CONCLUSION

The methylation levels in placenta tissues were associated with gestational ages. We indicated the expression levels of the significantly methylated genes were negatively correlated with the methylation levels, further functional researches were still needed to find out whether they are associated with the onset of preeclampsia.

The effects of placental long noncoding RNA H19 polymorphisms and promoter methylation on H19 expression in association with preeclampsia susceptibility

The effect of DNA methylation on gene expression triggered it as a susceptibility factor in various diseases including preeclampsia (PE). The pathogenesis of PE is closely associated with the methylation status and genetic variants of relevant genes. Therefore, the aim of the study was to investigate the possible impacts of the placental DNA methylation and rs3741219, rs217727, and rs2107425 polymorphisms of the H19 gene on the PE susceptibility as well as the its mRNA expression. Moreover, eight haplotypes of three loci in the H19 gene were analyzed. In this case-control study, the placentas of 107 preeclamptic and 113 non-preeclamptic women were collected after delivery. The methylation status was assessed by methylation-specific polymerase chain reaction (PCR). The H19 polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism or amplification refractory mutation system-polymerase chain reaction methods. The quantitative real time PCR was used for mRNA expression assay. The placental H19 rs3741219 and rs2107425 polymorphisms were not associated with PE. However, H19 rs217727CT and TT genotypes might be associated with a 9.2- and 17.7-fold increased risk of PE, respectively. The T_rs3741219 C_rs217727 C_rs2107425 and T_rs3741219 C_rs217727 T_rs2107425 haplotypes were significantly lower, whereas the T_rs3741219 T_rs217727 C_rs2107425 and C_rs3741219 T_rs217727 C_rs2107425 haplotypes were significantly higher in PE women. Promoter but not upstream region hypermethylation of H19 gene could be led to decreased risk of PE (MM vs. UM + UU). No significant difference was observed in the placental mRNA expression between two groups. The H19 expression was significantly higher in women with unmethylated (UU), compared to methylated promoter (MM). The H19 expression was 17- and 15-fold higher in H19-rs2107425 CC and CT genotypes in PE women. In conclusion, the H19 rs2107425 polymorphism was associated with a higher risk of PE and increased H19 mRNA expression. The promoter hypermethylation of H19 gene was associated with a lower risk of PE and decreased H19 mRNA expression.

Effect of maternal omega-3 fatty acids and vitamin E supplementation on placental apoptotic markers in rat model of early and late onset preeclampsia

AIM

Disturbed placentation results in pregnancy complications like preeclampsia. Placental development is influenced by apoptosis during trophoblast differentiation and proliferation. Increased oxidative stress upregulates placental apoptosis. We have earlier reported increased oxidative stress, lower omega-3 fatty acids and vitamin E levels in women with preeclampsia. Current study examines effect of maternal omega-3 fatty acids and vitamin E supplementation on apoptotic markers across gestation in a rat model of preeclampsia.

MAIN METHODS

Pregnant Wistar rats were randomly assigned to control; early onset preeclampsia (EOP); late onset preeclampsia (LOP); early onset preeclampsia + omega-3 fatty acid + vitamin E supplementation (EOP + O + E) and late onset preeclampsia + omega-3 fatty acid + vitamin E supplementation (LOP + O + E) groups. Animals (Control, EOP, EOP + O + E) were sacrificed at d14 and d20 of gestation while animals (LOP, LOP + O + E) were sacrificed at d20 to collect blood and placentae. Protein and mRNA levels of apoptotic markers were analyzed by ELISA and RT-PCR respectively.

KEY FINDINGS

Protein levels of proapoptotic markers like Bcl-2 associated X-protein (BAX) (p < 0.05), caspase-8 and 3 (p < 0.01 for both) and malondialdehyde (p < 0.01) were higher only in the EOP group as compared to control. However, the antiapoptotic marker, B cell lymphoma 2 (Bcl-2) protein levels were lower in both the subtypes of preeclampsia (p < 0.01 for both).

SIGNIFICANCE

Our findings suggest that supplementation was beneficial in reducing the caspase-8 and 3 in early onset preeclampsia but did not normalize BAX and Bcl-2 levels. This has implications for reducing placental apoptosis in preeclampsia.

Analysis of polymorphisms, promoter methylation, and mRNA expression profile of maternal and placental P53 and P21 genes in preeclamptic and normotensive pregnant women

Background

Preeclampsia (PE), as a multisystem disorder, is associated with maternal hypertension and proteinuria. Apoptosis seems to be involved in the pathophysiology of PE, although its precise pathogenic mechanisms are not well established. In this study, we aimed to identify the association between maternal TP53-rs1042522, P21-rs1801270, and P21-rs1059234 polymorphisms and PE. In addition, we examined the effects of promoter methylation and TP53 and P21 polymorphisms on placental mRNA expression in PE women.

Methods

The blood of 226 PE women and 228 normotensive pregnant women was examined in this study. In addition, the placentas were genotyped in 109 PE and 112 control women. The methylation status was assessed by a methylation-specific PCR assay, while mRNA expression was examined via Quantitative Real Time PCR.

Results

The maternal and placental P21-rs1801270 CA genotype had a significant association with the reduced risk of PE. In the dominant, recessive, and allelic models, maternal/placental P21-rs1059234 polymorphism had no statistically significant association with the risk of PE. On the other hand, the reduced risk of PE was associated with maternal, but not placental TP53-rs1042522 polymorphism in the dominant and recessive models. The maternal and placental P21-rs1801270 polymorphism was associated with PE risk. The maternal P21 T_rs1059234C_rs1801270 haplotype was associated with 3.4-fold increase in PE risk, However the maternal P21 T_rs1059234A_{rs 1801270} haplotype and placental C_rs1059234CA _rs1801270 haplotype led to 0.5 and 0.4-fold decrease in PE risk, respectively. PE women showed 5.6 times higher levels of placental mRNA expression of TP53 gene, although it was not associated with rs1042522 polymorphism. The relative placental mRNA expression of P21 gene was 0.2 in PE women. It was also 2.4 times higher in individuals with rs1801270CA genotype than those with AA genotype. The hyper-methylation of P21 and TP53 genes in the promoter region was associated with a 3.4-fold and 3-fold increase in PE risk, respectively. However, no association was found between P21 and TP53 mRNA expression and promoter methylation.

Conclusion

In conclusion, P21-rs1801270 and TP53-rs1042522 polymorphisms were involved in reduced risk of PE. P21-rs1801270 was associated with decreased P21 mRNA expression. The hyper-methylation of P21 and TP53 genes in the promoter region was associated with a higher PE risk.

Systematic large-scale meta-analysis identifies miRNA-429/200a/b and miRNA-141/200c clusters as biomarkers for necrotizing enterocolitis in newborn

Necrotizing enterocolitis (NEC) is a critical neonatal disease with a high mortality. The possibility that miRNAs may play an important role in NEC has raised great attention. Hence, the present study identified biomarkers that affected NEC in newborn progression through miRNA and gene expression profile analysis. miRNA chip GSE68054 and gene chip GSE46619 of NEC in newborn were analyzed to screen out differentially expressed miRNA and differentially expressed genes (DEGs). Next, target genes of differentially expressed miRNA were predicted, and differentially expressed miRNA-DEG regulatory network was constructed to select key miRNAs. After gene ontology and kyoto encyclopedia of genes and genomes enrichment analysis on target genes of key miRNAs, the target genes enriched in pathways were extracted to establish differentially expressed miRNA-DEG-disease gene network for gene interaction analysis. Targetting relationship between miRNAs and target genes was verified. A total of 15 miRNAs were differentially expressed in NEC in newborn, amongst which miR-429/200a/b and miR-141/200c clusters were poorly expressed and might play a significant role in NEC in newborn. Besides, target genes of miR-429/200a/b and miR-141/200c clusters were enriched in 11 signaling pathways. Vascular endothelial growth factor (VEGFA), E-selectin (SELE), kinase insert domain receptor (KDR), fms-related tyrosine kinase 1 (FLT1), and hepatocyte growth factor (HGF) were highly expressed in NEC in newborn, which were negatively regulated by miR-429/200a/b and miR-141/200c clusters and shared close association with disease genes. miR-429/200a/b and miR-141/200c clusters are poorly expressed while their target genes (VEGFA, SELE, KDR, FLT1, and HGF) are highly expressed in NEC in newborn, which might be identified as important biomarkers for this disease.

Differential placental DNA methylation of VEGFA and LEP in small-for-gestational age fetuses with an abnormal cerebroplacental ratio

Background

In Fetal Growth Restriction ‘fetal programming’ may take place via DNA methylation, which has implications for short-term and long-term health outcomes. Small-for-gestational age fetuses are considered fetal growth restricted, characterized by brain-sparing when fetal Doppler hemodynamics are abnormal, expressed as a cerebroplacental ratio (CPR) <1. We aimed to determine whether brain-sparing is associated with altered DNA methylation of selected genes.

Methods

We compared DNA methylation of six genes in 41 small-for-gestational age placentas with a normal or abnormal CPR. We selected EPO, HIF1A, VEGFA, LEP, PHLDA2, and DHCR24 for their role in angiogenesis, immunomodulation, and placental and fetal growth. DNA methylation was analyzed by pyrosequencing.

Results

Growth restricted fetuses with an abnormal CPR showed hypermethylation of the VEGFA gene at one CpG (VEGFA-309, p = .001) and an overall hypomethylation of the LEP gene, being significant at two CpGs (LEP-123, p = .049; LEP-51, p = .020). No differences in methylation were observed for the other genes.

Conclusions

VEGFA and LEP genes are differentially methylated in placentas of small-for-gestational age fetuses with brain-sparing. Hypermethylation of VEGFA-309 in abnormal CPR-placentas could indicate successful compensatory mechanisms. Methylation of LEP-51 is known to suppress LEP expression. Hypomethylation in small-for-gestational age placentas with abnormal CPR may result in hyperleptinemia and predispose to leptin-resistance later in life.

Association between Vascular Endothelial Growth Factor Gene Polymorphisms and Pre-Eclampsia Susceptibility: An Updated Meta-Analysis

Objectives: The aim of this study was to assess the genetic association between vascular endothelial growth factor (VEGF) gene polymorphisms and the risk of pre-eclampsia (PE).Methods: A systematic literature search of several databases (PubMed, Embase, and the China National Knowledge Infrastructure (CNKI)) was conducted for case-control trials comparing VEGF polymorphisms (+936C/T, -634G/C, -2578C/A, and -1154G/A) with the risk of PE. Meta-analysis was performed using the Stata 12.0 software.Results: Twenty-three case-control studies on a total of 2597 PE patients and 3075 controls were included in our meta-analysis. The +936C/T polymorphism was observed to be associated with the risk of PE in the overall population (T vs. C: odds ratios (OR) = 1.434, 95% confidence interval (CI) = 1.120-1.836, P = .004). However, the -634G/C, -2578C/A, and -1154G/A polymorphisms showed no association with the risk of PE. A subgroup analysis based on ethnicity found that the +936C/T polymorphism was associated with the risk of PE in both Europeans and Asians. Furthermore, the -634G/C polymorphism was found to be associated with the risk of PE in Europeans (C vs. G: OR = 1.428, 95% CI = 1.141-1.778, P = .002). The polymorphisms at other loci were not associated with the risk of PE.Conclusion: This meta-analysis suggests that VEGF +936C/T polymorphism, rather than -634G/C, -2578C/A, or -1154G/A polymorphisms, is associated with the risk of PE in the overall study population. However, the -634G/C polymorphism may be associated with the risk of developing PE in Europeans.

KDR (VEGFR2) Genetic Variants and Serum Levels in Patients with Rheumatoid Arthritis

We investigated kinase insert domain-containing receptor (KDR) polymorphisms and protein levels in relation to susceptibility to and severity of Rheumatoid Arthritis (RA). 641 RA patients and 340 controls (HC) were examined for the rs1870377 KDR variant by the polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method and for rs2305948 and rs2071559 KDR single nucleotide polymorphisms (SNPs) by TaqMan SNP genotyping assay. KDR serum levels were determined by enzyme-linked immunosorbent assay (ELISA). The rs1870377 KDR variant has shown association with RA under the codominant (p = 0.02, OR = 1.76, 95% CI = 1.09–2.85) and recessive models (p = 0.019, OR = 1.53, 95% CI = 1.07–2.20). KDR rs2305948 was associated with RA under the dominant model (p = 0.005, OR = 1.38, 95% CI = 1.10–1.73). Under the codominant model, the frequency of the rs2071559 TC and GG genotypes were lower in RA patients than in controls (p < 0.001, OR = 0.51, 95% CI = 0.37–0.69, and p = 0.002, OR = 0.57, 95% CI = 0.39–0.81). KDR rs2071559 T and rs2305948 A alleles were associated with RA (p = 0.001, OR = 0.60, 95% CI = 0.45–0.81 and p = 0.008, OR = 1.71, CI = 1.15–2.54). KDR rs2305948SNP was associated with Disease Activity Score (DAS)-28 score (p < 0.001), Visual Analog Scale (VAS) score (p < 0.001), number of swollen joints (p < 0.001), mean value of CRP (p < 0.001). A higher KDR serum level was found in RA patients than in HC (8018 pg/mL versus 7381 pg/mL, p = 0.002). Present results shed light on the role of KDR genetic variants in the severity of RA.

Role of vitamin D in influencing angiogenesis in preeclampsia

Objective: Vitamin D plays a key role during pregnancy and is involved in implantation and maintenance of pregnancy. Its deficiency is associated with pregnancy complications like preeclampsia, characterized by abnormal angiogenesis.Method: The current article summarises studies examining the role of vitamin D in pregnancy, with special emphasis on preeclampsia.Results and conclusion: An imbalance in pro- and anti-angiogenic factors is reported in women with preeclampsia. Cell culture studies have demonstrated that vitamin D can influence the process of angiogenesis. However, the role of maternal vitamin D in influencing placental angiogenesis in preeclampsia is unclear and needs to be explored.

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.

Differential global and MTHFR gene specific methylation patterns in preeclampsia and recurrent miscarriages: A case-control study from North India

AIM

The purpose of the present study is to evaluate and understand the association of global and MTHFR gene specific methylation in preeclampsia and recurrent miscarriages in light of MTHFR C677T polymorphism.

METHODS

The subjects comprised of recurrent miscarriage cases, their gestation matched controls, preeclampsia cases and matched controls. A set of women at full term were also recruited. Fasting blood sample (~5 ml) was drawn from all the participants followed by DNA extraction, global DNA methylation and MTHFR gene specific methylation. MTHFR C677T polymorphism was analysed by PCR followed by RFLP.

RESULTS HIGHER

Global DNA methylation at maternal front (p = 0.04) and hypomethylation of MTHFR gene at fetal front (p = 0.001) might be a characteristic of preeclampsia. Recurrent miscarriage cases were having significantly (p = 0.002) hyper MTHFR gene specific methylation as compared to controls. Women carrying CT genotype were found to be having significantly (p = 0.001) higher global DNA methylation in PE cases and MTHFR gene specific methylation (p = 0.005) in RM cases. Intergenerational analysis revealed similar patterns of global DNA methylation and MTHFR gene specific methylation among both PE and RM cases at maternal and fetal fronts.

CONCLUSION

The study highlights the importance of global DNA methylation in Preeclampsia and MTHFR gene specific methylation in recurrent miscarriages. MTHFR C677T gene polymorphism in association with global and gene specific methylation seem to play a pivotal role in PE and RM respectively.

Acute Hypoxia and Chronic Ischemia Induce Differential Total Changes in Placental Epigenetic Modifications

Preeclampsia is a common obstetrical complication, hallmarked by new-onset hypertension. Believed to result from placental insufficiency and chronic placental ischemia, the symptoms of preeclampsia are caused by release of pathogenic factors from the placenta itself, although the mechanisms of their regulation are in many cases unknown. One potential mechanism is through changes in placental epigenetic chromatin modifications, particularly histone acetylation and DNA methylation. Here, we determined the effects of chronic ischemia on global epigenetic modifications in the rodent placenta in vivo and acute hypoxia in BeWo placental trophoblast cells in vitro. Placental insufficiency via uterine artery restriction increased maternal blood pressure and fetal demise while decreasing placental and fetal mass. Global placental histone H3 acetylation levels were significantly decreased at H3 K9, K14, K18, K27, and K56. Interestingly, when BeWo-immortalized placental trophoblast cells were cultured in oxygen concentrations mimicking healthy and ischemic placentas, there was a significant increase in acetylated at K9, K18, K27, and K56. This was associated with a small but significant decrease in placental acetyl-CoA, suggesting depletion in the source of acetyl group donors. Finally, while global methylation of cytosine from placental DNA was low in both groups of animals (<1%), there was ∼50% increase in 5-mC in response to chronic ischemia. This suggests acute hypoxia and chronic ischemia induce differential global changes in histone acetylation in the placenta and that chronically altered metabolic profiles could affect histone acetylation in the placenta, thereby regulating production of pathogenic factors from the placenta during preeclampsia.

Supplementing punicalagin reduces oxidative stress markers and restores angiogenic balance in a rat model of pregnancy-induced hypertension

Pre-eclampsia (PE) is a pregnancy disorder that is characterised by severe hypertension and increased risks of foetal and maternal mortality. The aetiology of PE not completely understood; however, maternal nutrition and oxidative stress play important roles in the development of hypertension. The treatment options for PE are currently limited to anti-hypertensive drugs. Punicalagin, a polyphenol present in pomegranate juice, has a range of bioactive properties. The effects of supplementation with punicalagin on angiogenesis and oxidative stress in pregnant rats with induced hypertension were investigated. The pregnant rats were randomly divided into five experimental groups (n=12 per group). Hypertension was induced using an oral dose of NG-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg/day) on days 14-19 of pregnancy. Punicalagin (25, 50 or 100 mg/kg) was given orally on days 14-21 of pregnancy. Punicalagin treatment at the tested doses significantly reduced diastolic, systolic, and mean arterial blood pressure in L-NAME treated rats from day 14. Punicalagin also restored angiogenic balance by increasing the expression of vascular endothelial growth factor and downregulating vascular endothelial growth factor receptor-1/fms-like tyrosine kinase-1. Punicalagin, significantly increased the placental nitric oxide levels as compared to PE group. The increased levels of oxidative stress in rats with PE were markedly decreased by treatment with punicalagin. Punicalagin at the tested doses markedly (p<0.05) enhanced the placental antioxidant capacity in L-NAME-treated rats. The raised catalase activity observed following L-NAME induction was significantly (p<0.05) and restored to normal activity levels in punicalagin treatment. Further, 100 mg dose of punicalagin exhibited higher protective effects as compared to lower doses of 25 and 50 mg. This study shows that supplementation with punicalagin decreased blood pressure and oxidative stress and restored angiogenic balance in pregnant rats with induced PE.

Maternal one carbon metabolism through increased oxidative stress and disturbed angiogenesis can influence placental apoptosis in preeclampsia

Adequate maternal nutrition is critical for a healthy pregnancy outcome and poor maternal nutrition is known to be associated with pregnancy complications like preeclampsia. We have earlier demonstrated that there is an imbalance in the levels of micronutrients (folate and vitamin B₁₂) along with low levels of long chain polyunsaturated fatty acids (LCPUFA) and high homocysteine levels in women with preeclampsia. Homocysteine is known to be involved in the formation of free radicals leading to increased oxidative stress. Higher oxidative stress has been shown to be associated with increased apoptotic markers in the placenta. Preeclampsia is of placental origin and is associated with increased oxidative stress, disturbed angiogenesis and placental apoptosis. The process of angiogenesis is important for placental and fetal development and various angiogenic growth factors inhibit apoptosis by inactivation of proapoptotic proteins through a series of cellular signalling pathways. We propose that an altered one carbon cycle resulting in increased oxidative stress and impaired angiogenesis will contribute to increased placental apoptosis leading to preeclampsia. Understanding the association of one carbon cycle components and the possible mechanisms through which they regulate apoptosis will provide clues for reducing risk of pregnancy complications.

Epigenetic regulation of placental gene expression in transcriptional subtypes of preeclampsia

Background

Preeclampsia (PE) is a heterogeneous, hypertensive disorder of pregnancy, with no robust biomarkers or effective treatments. We hypothesized that this heterogeneity is due to the existence of multiple subtypes of PE and, in support of this hypothesis, we recently identified five clusters of placentas within a large gene expression microarray dataset (N = 330), of which four (clusters 1, 2, 3, and 5) contained a substantial number of PE samples. However, while transcriptional analysis of placentas can subtype patients, we propose that the addition of epigenetic information could discern gene regulatory mechanisms behind the distinct PE pathologies, as well as identify clinically useful potential biomarkers.

Results

We subjected 48 of our samples from transcriptional clusters 1, 2, 3, and 5 to Infinium HumanMethylation450 arrays. Samples belonging to transcriptional clusters 1–3 still showed visible relationships to each other by methylation, but cluster 5, with known chromosomal abnormalities, no longer formed a cohesive group. Within transcriptional clusters 2 and 3, controlling for fetal sex and gestational age in the identification of differentially methylated sites, compared to the healthier cluster 1, dramatically reduced the number of significant sites, but increased the percentage that demonstrated a strong linear correlation with gene expression (from 5% and 2% to 9% and 8%, respectively). Locations exhibiting a positive relationship between methylation and gene expression were most frequently found in CpG open sea enhancer regions within the gene body, while those with a significant negative correlation were often annotated to the promoter in a CpG shore region. Integrated transcriptome and epigenome analysis revealed modifications in TGF-beta signaling, cell adhesion, oxidative phosphorylation, and metabolism pathways in cluster 2 placentas, and aberrations in antigen presentation, allograft rejection, and cytokine-cytokine receptor interaction in cluster 3 samples.

Conclusions

Overall, we have established DNA methylation alterations underlying a portion of the transcriptional development of “canonical” PE in cluster 2 and “immunological” PE in cluster 3. However, a significant number of the observed methylation changes were not associated with corresponding changes in gene expression, and vice versa, indicating that alternate methods of gene regulation will need to be explored to fully comprehend these PE subtypes.

Electronic supplementary material

The online version of this article (10.1186/s13148-018-0463-6) contains supplementary material, which is available to authorized users.

Mining DNA methylation alterations towards a classification of placental pathologies

Placental health is a key component to a successful pregnancy. Placental insufficiency (PI), inadequate nutrient delivery to the fetus, is associated with preeclampsia (PE), a maternal hypertensive disorder, and intrauterine growth restriction (IUGR), pathologically poor fetal growth. PI is more common in early-onset PE (EOPE) than late-onset PE (LOPE). However, the relationship between these disorders remains unclear. While DNA methylation (DNAm) alterations have been identified in PE and IUGR, these entities can overlap and few studies have analysed them separately. This study aims to utilize DNAm profiling to better understand the underlying placental variation associated with PE and IUGR. Placental samples from a discovery (43 controls, 22 EOPE, 18 LOPE, 11 IUGR) and validation cohort (15 controls, 22 EOPE, 11 LOPE) were evaluated using the Illumina HumanMethylation450 array. To account for gestational age (GA) effects, EOPE samples were compared with pre-term births of varying etiologies (GA <37 weeks). LOPE and IUGR were compared with term controls (GA >37 weeks). While 1703 sites were differentially methylated (DM) (FDR < 0.05, Δβ > 0.1) in EOPE, few changes were associated with LOPE (N = 5), or IUGR (N = 0). Of the 1703 EOPE sites, 599 validated in the second cohort. Using these 599 sites, both cohorts clustered into three distinct groups. Interestingly, LOPE samples diagnosed between 34 and 36 weeks with co-occurring IUGR clustered with the EOPE. DNAm profiling may provide an independent tool to refine clinical/pathological diagnoses into subgroups with more uniform pathology. Despite large changes observed in EOPE, there were challenges in reproducing genome-wide DNAm hits that are discussed.

Promoter Methylation Status of WNT2 in Placenta from Patients with Preeclampsia

Background

Preeclampsia is a serious multisystem disorder of human gestation, affecting up to 10% of pregnant women worldwide, and results in maternal morbidity and mortality. The aim of this study was to determine the gene expression pattern and methylation status of the promoter of the WNT2 gene in placentas from patients with preeclampsia and to evaluate the potential role of the WNT2 pathway in the pathogenesis of preeclampsia.

Material/Methods

Real-time quantitative polymerase chain reaction (PT-PCR) was used to determine the WNT2 gene expression level. Western blot analysis was used to identify alterations in wnt2 protein expression.

Results

The mRNA and protein expression levels of the WNT2 gene were reduced in placentas from patients with preeclampsia when compared with placentas from healthy women. The average methylation level of the promoter of the WNT2 gene was elevated in the placentas from patients with preeclampsia compared with the controls placentas from healthy women.

Conclusions

The findings of this study have shown that molecular mechanisms, including aberrant activation of the WNT2 gene signaling pathway, may be involved in the pathogenesis of preeclampsia. Promoter hypermethylation and reduced expression of the WNT2 gene requires further study to determine a potential role in the diagnosis and treatment of preeclampsia.

DNA methylation-mediated silencing of FLT1 in parthenogenetic porcine placentas

Studies show that perturbed expression of vascular endothelial growth factor (VEGF) family genes is related to abnormal development of parthenogenetic (PA) placenta. In this study, the methylation status of VEGF family genes were compared between PA and normal placentas using bisulfite sequencing PCR (BSP). Results showed no significant difference in the methylation of VEGF-A differentially methylated region (DMR), placental growth factor (PIGF) DMR, and kinase insert domain receptor (KDR) DMR, whereas FMS-like tyrosine kinase 1 (FLT1) DMR was hypermethylated in PA placentas. These results suggested that abnormal methylation of FLT1 DMR might trigger the developmental failure of porcine PA placentas.

Potential role of the methylation of VEGF gene promoter in response to hypoxia in oxygen-induced retinopathy: beneficial effect of the absence of AQP4

Hypoxia‐dependent accumulation of vascular endothelial growth factor (VEGF) plays a major role in retinal diseases characterized by neovessel formation. In this study, we investigated whether the glial water channel Aquaporin‐4 (AQP4) is involved in the hypoxia‐dependent VEGF upregulation in the retina of a mouse model of oxygen‐induced retinopathy (OIR). The expression levels of VEGF, the hypoxia‐inducible factor‐1α (HIF‐1α) and the inducible form of nitric oxide synthase (iNOS), the production of nitric oxide (NO), the methylation status of the HIF‐1 binding site (HBS) in the VEGF gene promoter, the binding of HIF‐1α to the HBS, the retinal vascularization and function have been determined in the retina of wild‐type (WT) and AQP4 knock out (KO) mice under hypoxic (OIR) or normoxic conditions. In response to 5 days of hypoxia, WT mice were characterized by (i) AQP4 upregulation, (ii) increased levels of VEGF, HIF‐1α, iNOS and NO, (iii) pathological angiogenesis as determined by engorged retinal tufts and (iv) dysfunctional electroretinogram (ERG). AQP4 deletion prevents VEGF, iNOS and NO upregulation in response to hypoxia thus leading to reduced retinal damage although in the presence of high levels of HIF‐1α. In AQP4 KO mice, HBS demethylation in response to the beginning of hypoxia is lower than in WT mice reducing the binding of HIF‐1α to the VEGF gene promoter. We conclude that in the absence of AQP4, an impaired HBS demethylation prevents HIF‐1 binding to the VEGF gene promoter and the relative VEGF transactivation, reducing the VEGF‐induced retinal damage in response to hypoxia.

Consensus strategy in genes prioritization and combined bioinformatics analysis for preeclampsia pathogenesis

BACKGROUND

Preeclampsia is a multifactorial disease with unknown pathogenesis. Even when recent studies explored this disease using several bioinformatics tools, the main objective was not directed to pathogenesis. Additionally, consensus prioritization was proved to be highly efficient in the recognition of genes-disease association. However, not information is available about the consensus ability to early recognize genes directly involved in pathogenesis. Therefore our aim in this study is to apply several theoretical approaches to explore preeclampsia; specifically those genes directly involved in the pathogenesis.

METHODS

We firstly evaluated the consensus between 12 prioritization strategies to early recognize pathogenic genes related to preeclampsia. A communality analysis in the protein-protein interaction network of previously selected genes was done including further enrichment analysis. The enrichment analysis includes metabolic pathways as well as gene ontology. Microarray data was also collected and used in order to confirm our results or as a strategy to weight the previously enriched pathways.

RESULTS

The consensus prioritized gene list was rationally filtered to 476 genes using several criteria. The communality analysis showed an enrichment of communities connected with VEGF-signaling pathway. This pathway is also enriched considering the microarray data. Our result point to VEGF, FLT1 and KDR as relevant pathogenic genes, as well as those connected with NO metabolism.

CONCLUSION

Our results revealed that consensus strategy improve the detection and initial enrichment of pathogenic genes, at least in preeclampsia condition. Moreover the combination of the first percent of the prioritized genes with protein-protein interaction network followed by communality analysis reduces the gene space. This approach actually identifies well known genes related with pathogenesis. However, genes like HSP90, PAK2, CD247 and others included in the first 1% of the prioritized list need to be further explored in preeclampsia pathogenesis through experimental approaches.

VEGF and VEGFR1 levels in different regions of the normal and preeclampsia placentae

Altered placental angiogenesis is implicated in the pathophysiology of preeclampsia. We have earlier reported placental regional differences in oxidative stress markers and neurotrophins. Oxidative stress and neurotrophins are reported to regulate angiogenesis. This study aims to examine protein and mRNA levels of vascular endothelial growth factor (VEGF) and VEGF receptor 1 (VEGFR1) in four regions [central maternal (CM), central fetal (CF), peripheral maternal (PM), and peripheral fetal (PF)] of the placenta in normotensive control (NC) women (n = 51) and women with preeclampsia (PE) (n = 43) [18 delivered at term (T-PE) and 25 delivered preterm (PT-PE)]. In all groups, CF region reported highest VEGF protein levels compared to all other regions. VEGF mRNA level was higher in CF region as compared to CM region in PE group (p < 0.05). VEGF levels were lower in all regions of PE, T-PE, and PT-PE groups (p < 0.05) as compared to their respective regions in NC group. VEGFR1 levels were lower in CF (p < 0.05) and PF (p < 0.01) regions as compared to CM region only in control. However, VEGFR1 levels were higher in CF (p < 0.05) and PF (p < 0.01) regions of PT-PE group as compared to control. VEGFR1 mRNA level was higher in PM region of PE group and T-PE group (p < 0.05 for both) as compared to control. VEGF levels in the PF region were positively associated with birth weight and placental weight. This study describes placental regional changes in angiogenic factors particularly highlighting increased VEGF in CF region possibly in response to hypoxic conditions prevailing in placenta.