Gene expression in the intestine of newborn piglets after hypoxia-reoxygenation.

BACKGROUND: In preterm infants, intestinal hypoxia may partly contribute to the pathophysiology of necrotizing enterocolitis through changes in gene expression. Splanchnic hypoxia can be detected with monitoring of regional splanchnic oxygen saturation (rsSO2). Using a piglet model of asphyxia, we aimed to correlate changes in rsSO2 to gene expression. METHODS: Forty-two newborn piglets were randomized to control or intervention groups. Intervention groups were subjected to hypoxia until they were acidotic and hypotensive. Next, they were reoxygenated for 30 min according to randomization, i.e., 21% O2, 100% O2, or 100% O2 for 3 min followed by 21% O2, and observed for 9 h. We continuously measured rsSO2 and calculated mean rsSO2 and variability of rsSO2 (rsCoVar = SD/mean). Samples of terminal ileum were analyzed for mRNA expression of selected genes related to inflammation, erythropoiesis, fatty acid metabolism, and apoptosis. RESULTS: The expression of selected genes was not significantly different between control and intervention groups. No associations between mean rsSO2 and gene expression were observed. However, lower rsCoVar was associated with the upregulation of apoptotic genes and the downregulation of inflammatory genes (P < 0.05). CONCLUSION: Our study suggests that hypoxia and reoxygenation cause reduced vascular adaptability, which seems to be associated with the upregulation of apoptosis and downregulation of inflammation. IMPACT: Our results provide important insight into the (patho)physiological significance of changes in the variability of rsSO2. Our findings may advance future research and clinical practice regarding resuscitation strategies of preterm infants.

Growth-Restricted Fetuses and Offspring Reveal Adverse Sex-Specific Metabolic Responses in Preeclamptic Mice Expressing Human sFLT1.

Fetal adaptations to harmful intrauterine environments due to pregnancy disorders such as preeclampsia (PE) can negatively program the offspring's metabolism, resulting in long-term metabolic changes. PE is characterized by increased circulating levels of sFLT1, placental dysfunction and fetal growth restriction (FGR). Here we examine the consequences of systemic human sFLT1 overexpression in transgenic PE/FGR mice on the offspring's metabolic phenotype. Histological and molecular analyses of fetal and offspring livers as well as examinations of offspring serum hormones were performed. At 18.5 dpc, sFLT1 overexpression resulted in growth-restricted fetuses with a reduced liver weight, combined with reduced hepatic glycogen storage and histological signs of hemorrhages and hepatocyte apoptosis. This was further associated with altered gene expression of the molecules involved in fatty acid and glucose/glycogen metabolism. In most analyzed features males were more affected than females. The postnatal follow-up revealed an increased weight gain of male PE offspring, and increased serum levels of Insulin and Leptin. This was associated with changes in hepatic gene expression regulating fatty acid and glucose metabolism in male PE offspring. To conclude, our results indicate that sFLT1-related PE/FGR in mice leads to altered fetal liver development, which might result in an adverse metabolic pre-programming of the offspring, specifically targeting males. This could be linked to the known sex differences seen in PE pregnancies in human.

LPS versus Poly I:C model: comparison of long-term effects of bacterial and viral maternal immune activation on the offspring.

A prominent health issue nowadays is the COVID-19 pandemic, which poses acute risks to human health. However, the long-term health consequences are largely unknown and cannot be neglected. An especially vulnerable period for infection is pregnancy, when infections could have long-term health effect on the child. Evidence suggests that maternal immune activation (MIA) induced by either bacteria or viruses presents various effects on the offspring, leading to adverse phenotypes in many organ systems. This review compares the mechanisms of bacterial and viral MIA and the possible long-term outcomes for the offspring by summarizing the outcome in animal LPS and Poly I:C models. Both models are activated immune responses mediated by Toll-like receptors. The outcomes for MIA offspring include neurodevelopment, immune response, circulation, metabolism, and reproduction. Some of these changes continue to exist until later life. Besides different doses and batches of LPS and Poly I:C, the injection day, administration route, and also different animal species influence the outcomes. Here, we specifically aim to support colleagues when choosing their animal models for future studies.

Prenatal smoke effect on mouse offspring Igf1 promoter methylation from fetal stage to adulthood is organ and sex specific.

Prenatal smoke exposure (PSE) is associated with reduced birth weight, impaired fetal development, and increased risk for diseases later in life. Changes in DNA methylation may be involved, as multiple large-scale epigenome-wide association studies showed that PSE is robustly associated with DNA methylation changes in blood among offspring in early life. Insulin-like growth factor-1 (IGF1) is important in growth, differentiation, and repair processes after injury. However, no studies investigated the organ-specific persistence of PSE-induced methylation change of Igf1 into adulthood. Based on our previous studies on the PSE effect on Igf1 promoter methylation in fetal and neonatal mouse offspring, we now have extended our studies to adulthood. Our data show that basal Igf1 promoter methylation generally increased in the lung but decreased in the liver (except for 2 persistent CpG sites in both organs) across three different developmental stages. PSE changed Igf1 promoter methylation in all three developmental stages, which was organ and sex specific. The PSE effect was less pronounced in adult offspring compared with the fetal and neonatal stages. In addition, the PSE effect in the adult stage was more pronounced in the lung compared with the liver. For most CpG sites, an inverse correlation was found for promoter methylation and mRNA expression when the data of all three stages were combined. This was more prominent in the liver. Our findings provide additional evidence for sex- and organ-dependent prenatal programming, which supports the developmental origins of health and disease (DOHaD) hypothesis.

Early-onset preeclampsia, plasma microRNAs, and endothelial cell function.

BACKGROUND: Preeclampsia is a hypertensive pregnancy disorder in which generalized systemic inflammation and maternal endothelial dysfunction are involved in the pathophysiology. MiRNAs are small noncoding RNAs responsible for post-transcriptional regulation of gene expression and involved in many physiological processes. They mainly downregulate translation of their target genes. OBJECTIVE: We aimed to compare the plasma miRNA concentrations in preeclampsia, healthy pregnant women, and nonpregnant women. Furthermore, we aimed to evaluate the effect of 3 highly increased plasma miRNAs in preeclampsia on endothelial cell function in vitro. STUDY DESIGN: We compared 3391 (precursor) miRNA concentrations in plasma samples from early-onset preeclamptic women, gestational age-matched healthy pregnant women, and nonpregnant women using miRNA 3.1. arrays (Affymetrix) and validated our findings by real-time quantitative polymerase chain reaction. Subsequently, endothelial cells (human umbilical vein endothelial cells) were transfected with microRNA mimics (we choose the 3 miRNAs with the greatest fold change and lowest false-discovery rate in preeclampsia vs healthy pregnancy). After transfection, functional assays were performed to evaluate whether overexpression of the microRNAs in endothelial cells affected endothelial cell function in vitro. Functional assays were the wound-healing assay (which measures cell migration and proliferation), the proliferation assay, and the tube-formation assay (which assesses formation of endothelial cell tubes during the angiogenic process). To determine whether the miRNAs are able to decrease gene expression of certain genes, RNA was isolated from transfected endothelial cells and gene expression (by measuring RNA expression) was evaluated by gene expression microarray (Genechip Human Gene 2.1 ST arrays; Life Technologies). For the microarray, we used pooled samples, but the differently expressed genes in the microarray were validated by real-time quantitative polymerase chain reaction in individual samples. RESULTS: No significant differences (fold change <-1.2 or >1.2 with a false-discovery rate <0.05) were found in miRNA plasma concentrations between healthy pregnant and nonpregnant women. The plasma concentrations of 26 (precursor) miRNAs were different between preeclampsia and healthy pregnancy. The 3 miRNAs that were increased with the greatest fold change and lowest false-discovery rate in preeclampsia vs healthy pregnancy were miR-574-5p, miR-1972, and miR-4793-3p. Transfection of endothelial cells with these miRNAs in showed that miR-574-5p decreased (P<.05) the wound-healing capacity (ie, decreased endothelial cell migration and/or proliferation) and tended (P<.1) to decrease proliferation, miR-1972 decreased tube formation (P<.05), and also tended (P<.1) to decrease proliferation, and miR-4793-3p tended (P<.1) to decrease both the wound-healing capacity and tube formation in vitro. Gene expression analysis of transfected endothelial cells revealed that miR-574-5p tended (P<.1) to decrease the expression of the proliferation marker MKI67. CONCLUSION: We conclude that in the early-onset preeclampsia group in our study different concentrations of plasma miRNAs are present as compared with healthy pregnancy. Our results suggest that miR-574-5p and miR-1972 decrease the proliferation (probably via decreasing MKI67) and/or migration as well as the tube-formation capacity of endothelial cells. Therefore, these miRNAs may be antiangiogenic factors affecting endothelial cells in preeclampsia.

Postnatal Smoke Exposure Further Increases the Hepatic Nicotine Metabolism in Prenatally Smoke Exposed Male Offspring and Is Linked with Aberrant Cyp2a5 Methylation.

Prenatal smoke exposure (PreSE) is a risk factor for nicotine dependence, which is further enhanced by postnatal smoke exposure (PostSE). One susceptibility gene to nicotine dependence is Cytochrome P450 (CYP) 2A6, an enzyme responsible for the conversion of nicotine to cotinine in the liver. Higher CYP2A6 activity is associated with nicotine dependence and could be regulated through DNA methylation. In this study we investigated whether PostSE further impaired PreSE-induced effects on nicotine metabolism, along with Cyp2a5, orthologue of CYP2A6, mRNA expression and DNA methylation. Using a mouse model where prenatally smoke-exposed adult offspring were exposed to cigarette smoke for 3 months, enzyme activity, mRNA levels, and promoter methylation of hepatic Cyp2a5 were evaluated. We found that in male offspring, PostSE increased PreSE-induced cotinine levels and Cyp2a5 mRNA expression. In addition, both PostSE and PreSE changed Cyp2a5 DNA methylation in male groups. PreSE however decreased cotinine levels whereas it had no effect on Cyp2a5 mRNA expression or methylation. These adverse outcomes of PreSE and PostSE were most prominent in males. When considered in the context of the human health aspects, the combined effect of prenatal and adolescent smoke exposure could lead to an accelerated risk for nicotine dependence later in life.

Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance.

Postnatal overfeeding increases the risk of chronic diseases later in life, including obesity, insulin resistance, hepatic steatosis, and type 2 diabetes. Epigenetic mechanisms might underlie the long-lasting effects associated with early nutrition. Here we aimed to explore the molecular pathways involved in early development of insulin resistance and hepatic steatosis, and we examined the potential contribution of DNA methylation and histone modifications to long-term programming of metabolic disease. We used a well-characterized mouse model of neonatal overfeeding and early adiposity by litter size reduction. Neonatal overfeeding led to hepatic insulin resistance very early in life that persisted throughout adulthood despite normalizing food intake. Up-regulation of monoacylglycerol O-acyltransferase ( Mogat) 1 conceivably mediates hepatic steatosis and insulin resistance through increasing intracellular diacylglycerol content. Early and sustained deregulation of Mogat1 was associated with a combination of histone modifications that might favor Mogat1 expression. In sum, postnatal overfeeding causes extremely rapid derangements of hepatic insulin sensitivity that remain relatively stable until adulthood. Epigenetic mechanisms, particularly histone modifications, could contribute to such long-lasting effects. Our data suggest that targeting hepatic monoacylglycerol acyltransferase activity during early life might provide a novel strategy to improve hepatic insulin sensitivity and prevent late-onset insulin resistance and fatty liver disease.-Ramon-Krauel, M., Pentinat, T., Bloks, V. W., Cebrià, J., Ribo, S., Pérez-Wienese, R., Vilà, M., Palacios-Marin, I., Fernández-Pérez, A., Vallejo, M., Téllez, N., Rodríguez, M. À., Yanes, O., Lerin, C., Díaz, R., Plosch, T., Tietge, U. J. F., Jimenez-Chillaron, J. C. Epigenetic programming at the Mogat1 locus may link neonatal overnutrition with long-term hepatic steatosis and insulin resistance.

Inhibiting Cholesterol Absorption During Lactation Programs Future Intestinal Absorption of Cholesterol in Adult Mice.

In nematodes, the intestine senses and integrates early life dietary cues that lead to lifelong epigenetic adaptations to a perceived nutritional environment-it is not clear whether this process occurs in mammals. We aimed to establish a mouse model of reduced dietary cholesterol availability from maternal milk and investigate the consequences of decreased milk cholesterol availability, early in life, on the metabolism of cholesterol in adult mice. We blocked intestinal absorption of cholesterol in milk fed to newborn mice by supplementing the food of dams (for 3 weeks between birth and weaning) with ezetimibe, which is secreted into milk. Ezetimibe interacts with the intestinal cholesterol absorption transporter NPC1l1 to block cholesterol uptake into enterocytes. Characterization of these offspring at 24 weeks of age showed a 27% decrease in cholesterol absorption (P < .001) and reduced levels of Npc1l1 messenger RNA and protein, but not other cholesterol transporters, in the proximal small intestine. We observed increased histone H3K9me3 methylation at positions -423 to -607 of the proximal Npc1l1 promoter in small intestine tissues from 24-week-old offspring fed ezetimibe during lactation, compared with controls. These findings show that the early postnatal mammalian intestine functions as an environmental sensor of nutritional conditions, responding to conditions such as low cholesterol levels by epigenetic modifications of genes. Further studies are needed to determine how decreased sterol absorption for a defined period might activate epigenetic regulators; the findings of our study might have implications for human infant nutrition and understanding and preventing cardiometabolic disease.

Placental insufficiency contributes to fatty acid metabolism alterations in aged female mouse offspring.

Intrauterine growth restriction (IUGR) is an accepted risk factor for metabolic disorders in later life, including obesity and type 2 diabetes. The level of metabolic dysregulation can vary between subjects and is dependent on the severity and the type of IUGR insult. Classical IUGR animal models involve nutritional deprivation of the mother or uterine artery ligation. The latter aims to mimic a placental insufficiency, which is the most frequent cause of IUGR. In this study, we investigated whether IUGR attributable to placental insufficiency impacts the glucose and lipid homeostasis at advanced age. Placental insufficiency was achieved by deletion of the transcription factor AP-2y ( Tfap2c), which serves as one of the major trophoblast differentiation regulators. TdelT-IUGR mice were obtained by crossing mice with a floxed Tfap2c allele and mice with Cre recombinase under the control of the Tpbpa promoter. In advanced adulthood (9-12 mo), female and male IUGR mice are respectively 20% and 12% leaner compared with controls. At this age, IUGR mice have unaffected glucose clearance and lipid parameters (cholesterol, triglycerides, and phospholipids) in the liver. However, female IUGR mice have increased plasma free fatty acids (+87%) compared with controls. This is accompanied by increased mRNA levels of fatty acid synthase and endoplasmic reticulum stress markers in white adipose tissue. Taken together, our results suggest that IUGR by placental insufficiency may lead to higher lipogenesis in female mice in advanced adulthood, at least indicated by greater Fasn expression. This effect was sex specific for the aged IUGR females.

Early micronutrient supplementation protects against early stress-induced cognitive impairments.

Early-life stress (ES) impairs cognition later in life. Because ES prevention is problematic, intervention is needed, yet the mechanisms that underlie ES remain largely unknown. So far, the role of early nutrition in brain programming has been largely ignored. Here, we demonstrate that essential 1-carbon metabolism-associated micronutrients (1-CMAMs; i.e., methionine and B vitamins) early in life are crucial in programming later cognition by ES. ES was induced in male C57Bl/6 mice from postnatal d (P)2-9. 1-CMAM levels were measured centrally and peripherally by using liquid chromatography-mass spectroscopy. Next, we supplemented the maternal diet with 1-CMAM only during the ES period and studied cognitive, neuroendocrine, neurogenic, transcriptional, and epigenetic changes in adult offspring. We demonstrate that ES specifically reduces methionine in offspring plasma and brain. Of note, dietary 1-CMAM enrichment during P2-9 restored methionine levels and rescued ES-induced adult cognitive impairments. Beneficial effects of this early dietary enrichment were associated with prevention of the ES-induced rise in corticosterone and adrenal gland hypertrophy did not involve changes in maternal care, hippocampal volume, neurogenesis, or global/Nr3c1-specific DNA methylation. In summary, nutrition is important in brain programming by ES. A short, early supplementation with essential micronutrients can already prevent lasting effects of ES. This concept opens new avenues for nutritional intervention.-Naninck, E. F. G., Oosterink, J. E., Yam, K.-Y., de Vries, L. P., Schierbeek, H., van Goudoever, J. B., Verkaik-Schakel, R.-N., Plantinga, J. A., Plosch, T., Lucassen, P. J., Korosi, A. Early micronutrient supplementation protects against early stress-induced cognitive impairments.

Placental-Specific Overexpression of sFlt-1 Alters Trophoblast Differentiation and Nutrient Transporter Expression in an IUGR Mouse Model.

Since it is known that placental overexpression of the human anti-angiogenic molecule sFlt-1, the main candidate in the progression of preeclampsia, lead to intrauterine growth restriction (IUGR) in mice by lentiviral transduction of mouse blastocysts, we hypothesize that sFlt-1 influence placental morphology and physiology resulting in fetal IUGR. We therefore examined the effect of sFlt-1 on placental morphology and physiology at embryonic day 18.5 with histologic and morphometric analyses, transcript analyses, immunoblotting, and methylation studies. Interestingly, placental overexpression of sFlt-1 leads to IUGR in the fetus and results in lower placental weights. Moreover, we observed altered trophoblast differentiation with reduced expression of IGF2, resulting in a smaller placenta, a smaller labyrinth, and the loss of glycogen cells in the junctional zone. Changes in IGF2 are accompanied by small changes in its DNA methylation, whereas overall DNA methylation is unaffected. In addition, the expression of placental nutrient transporters, such as the glucose diffusion channel Cx26, is decreased. In contrast, the expression of the fatty acid transporter CD36 and the cholesterol transporter ABCA1 is significantly increased. In conclusion, placental sFlt-1 overexpression resulted in a reduction in the differentiation of the spongiotrophoblast into glycogen cells. These findings of a reduced exchange area of the labyrinth and glycogen stores, as well as decreased expression of glucose transporter, could contribute to the intrauterine growth restriction phenotype. All of these factors change the intrauterine availability of nutrients. Thus, we speculate that the alterations triggered by increased anti-angiogenesis strongly affect fetal outcome and programming. J. Cell. Biochem. 118: 1316-1329, 2017. © 2016 Wiley Periodicals, Inc.

Cholesterol metabolism in rabbit blastocysts under maternal diabetes.

In the rabbit reproductive model, maternal experimentally induced insulin-dependent diabetes mellitus (expIDD) leads to accumulation of lipid droplets in blastocysts. Cholesterol metabolism is a likely candidate to explain such metabolic changes. Therefore, in the present study we analysed maternal and embryonic cholesterol concentrations and expression of related genes in vivo (diabetic model) and in vitro (embryo culture in hyperglycaemic medium). In pregnant expIDD rabbits, the serum composition of lipoprotein subfractions was changed, with a decrease in high-density lipoprotein cholesterol and an increase in very low-density lipoprotein cholesterol; in uterine fluid, total cholesterol concentrations were elevated. Expression of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), very low-density lipoprotein receptor (VLDLR), sterol regulatory element binding transcription factor 2 (SREBF2), insulin-induced gene-1 (INSIG1) and cholesterol 7α-hydroxylase (CYP7A1) mRNA was decreased in the liver and low-density lipoprotein receptor (LDLR) mRNA expression was decreased in the adipose tissue of diabetic rabbits. In embryos from diabetic rabbits, the mean (±s.e.m.) ratio of cholesterol concentrations in trophoblasts to embryoblasts was changed from 1.27±2.34 (control) to 0.88±3.85 (expIDD). Rabbit blastocysts expressed HMGCR, LDLR, VLDLR, SREBF2 and INSIG1 but not CYP7A1, without any impairment of expression as a result of maternal diabetes. In vitro hyperglycaemia decreased embryonic HMGCR and SREBF2 transcription in rabbit blastocysts. The findings of the present study show that a diabetic pregnancy leads to distinct changes in maternal cholesterol metabolism with a minor effect on embryo cholesterol metabolism.

The peroxisome proliferator-activated receptors under epigenetic control in placental metabolism and fetal development.

The placental metabolism can adapt to the environment throughout pregnancy to both the demands of the fetus and the signals from the mother. Such adaption processes include epigenetic mechanisms, which alter gene expression and may influence the offspring's health. These mechanisms are linked to the diversity of prenatal environmental exposures, including maternal under- or overnutrition or gestational diabetes. The peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that contribute to the developmental plasticity of the placenta by regulating lipid and glucose metabolism pathways, including lipogenesis, steroidogenesis, glucose transporters, and placental signaling pathways, thus representing a link between energy metabolism and reproduction. Among the PPAR isoforms, PPARγ appears to be the main modulator of mammalian placentation. Certain fatty acids and lipid-derived moieties are the natural activating PPAR ligands. By controlling the amounts of maternal nutrients that go across to the fetus, the PPARs play an important regulatory role in placenta metabolism, thereby adapting to the maternal nutritional status. As demonstrated in animal studies, maternal nutrition during gestation can exert long-term influences on the PPAR methylation pattern in offspring organs. This review underlines the current state of knowledge on the relationship between environmental factors and the epigenetic regulation of the PPARs in placenta metabolism and offspring development.

Parental vitamin D deficiency during pregnancy is associated with increased blood pressure in offspring via Panx1 hypermethylation.

Vitamin D deficiency is one of the most common nutritional deficiencies worldwide. Maternal vitamin D deficiency is associated with increased susceptibility to hypertension in offspring, but the reasons for this remain unknown. The aim of this study was to determine if parental vitamin D deficiency leads to altered DNA methylation in offspring that may relate to hypertension. Male and female Sprague-Dawley rats were fed a standard or vitamin D-depleted diet. After 10 wk, nonsibling rats were mated. The conceived pups received standard chow. We observed an increased systolic and diastolic blood pressure in the offspring from depleted parents (F1-depl). Genome-wide methylation analyses in offspring identified hypermethylation of the promoter region of the Pannexin-1 (Panx1) gene in F1-depl rats. Panx1 encodes a hemichannel known to be involved in endothelial-dependent relaxation, and we demonstrated that in F1-depl rats the increase in blood pressure was associated with impaired endothelial relaxation of the large vessels, suggesting an underlying biological mechanism of increased blood pressure in children from parents with vitamin deficiency. Parental vitamin D deficiency is associated with epigenetic changes and increased blood pressure levels in offspring.

Preeclampsia As Modulator of Offspring Health.

A balanced intrauterine homeostasis during pregnancy is crucial for optimal growth and development of the fetus. The intrauterine environment is extremely vulnerable to multisystem pregnancy disorders such as preeclampsia, which can be triggered by various pathophysiological factors, such as angiogenic imbalance, immune responses, and inflammation. The fetus adapts to these conditions by a mechanism known as developmental programming that can lead to increased risk of chronic noncommunicable diseases in later life. This is shown in a substantial number of epidemiological studies that associate preeclampsia with increased onset of cardiovascular and metabolic diseases in the later life of the offspring. Furthermore, animal models based predominantly on one of the pathophysiological mechanism of preeclampsia, for example, angiogenic imbalance, immune response, or inflammation, do address the susceptibility of the preeclamptic offspring to increased maternal blood pressure and disrupted metabolic homeostasis. Accordingly, we extensively reviewed the latest research on the role of preeclampsia on the offspring's metabolism and cardiovascular phenotype. We conclude that future research on the pathophysiological changes during preeclampsia and methods to intervene in the harsh intrauterine environment will be essential for effective therapies.

DNA Methylation and Expression Patterns of Selected Genes in First-Trimester Placental Tissue from Pregnancies with Small-for-Gestational-Age Infants at Birth.

Variations in DNA methylation levels in the placenta are thought to influence gene expression and are associated with complications of pregnancy, like fetal growth restriction (FGR). The most important cause for FGR is placental dysfunction. Here, we examined whether changes in DNA methylation, followed by gene expression changes, are mechanistically involved in the etiology of FGR. In this retrospective case-control study, we examined the association between small-for-gestational-age (SGA) children and both DNA methylation and gene expression levels of the genes WNT2, IGF2/H19, SERPINA3, HERVWE1, and PPARG in first-trimester placental tissue. We also examined the repetitive element LINE-1. These candidate genes have been reported in the literature to be associated with SGA. We used first-trimester placental tissue from chorionic villus biopsies. A total of 35 SGA children (with a birth weight below the 10th percentile) were matched to 70 controls based on their gestational age. DNA methylation levels were analyzed by pyrosequencing and mRNA levels were analyzed by real-time PCR. None of the average DNA methylation levels, measured for each gene, showed a significant difference between SGA placental tissue compared to control tissue. However, hypermethylation of WNT2 was detected on two CpG positions in SGA. This was not associated with changes in gene expression. Apart from two CpG positions of the WNT2 gene, in early placenta samples, no evident changes in DNA methylation or expression were found. This indicates that the already reported changes in term placenta are not present in the early placenta, and therefore must arise after the first trimester.

The Gut Microbiota and their Metabolites: Potential Implications for the Host Epigenome.

The gut microbiota represents a metabolically active biomass of up to 2 kg in adult humans. Microbiota-derived molecules significantly contribute to the host metabolism. Large amounts of bacterial metabolites are taken up by the host and are subsequently utilized by the human body. For instance, short chain fatty acids produced by the gut microbiota are a major energy source of humans.It is widely accepted that microbiota-derived metabolites are used as fuel for beta-oxidation (short chain fatty acids) and participate in many metabolic processes (vitamins, such as folic acid). Apart from these direct metabolic effects, it also becomes more and more evident that these metabolites can interact with the mammalian epigenetic machinery. By interacting with histones and DNA they may be able to manipulate the host's chromatin state and functionality and hence its physiology and health.In this chapter, we summarize the current knowledge on possible interactions of different bacterial metabolites with the mammalian epigenetic machinery, mostly based on in vitro data. We discuss the putative impact on chromatin marks, for example histone modifications and DNA methylation. Subsequently, we speculate about possible beneficial and adverse consequences for the epigenome, the physiology and health of the host, as well as plausible future applications of this knowledge for in vivo translation to support personal health.

The role of mesenchymal stem cells in early programming of adipose tissue in the offspring of women with obesity.

Maternal obesity is a well-known risk factor for developing premature obesity, metabolic syndrome, cardiovascular disease and type 2 diabetes in the progeny. The development of white adipose tissue is a dynamic process that starts during prenatal life: fat depots laid down in utero are associated with the proportion of fat in children later on. How early this programming takes place is still unknown. However, recent evidence shows that mesenchymal stem cells (MSC), the embryonic adipocyte precursor cells, show signatures of the early setting of an adipogenic committed phenotype when exposed to maternal obesity. This review aims to present current findings on the cellular adaptations of MSCs from the offspring of women with obesity and how the metabolic environment of MSCs could affect the early commitment towards adipocytes. In conclusion, maternal obesity can induce early programming of fetal adipose tissue by conditioning MSCs. These cells have higher expression of adipogenic markers, altered insulin signalling and mitochondrial performance, compared to MSCs of neonates from lean pregnancies. Fetal MSCs imprinting by maternal obesity could help explain the increased risk of childhood obesity and development of further noncommunicable diseases.

Sex-Specific Transcriptomic Changes in the Villous Tissue of Placentas of Pregnant Women Using a Selective Serotonin Reuptake Inhibitor.

About 5% of pregnant women are treated with selective serotonin reuptake inhibitor (SSRI) antidepressants to treat their depression. SSRIs influence serotonin levels, a key factor in neural embryonic development, and their use during pregnancy has been associated with adverse effects on the developing embryo. However, the role of the placenta in transmitting these negative effects is not well understood. In this study, we aim to elucidate how disturbances in the maternal serotonergic system affect the villous tissue of the placenta by assessing whole transcriptomes in the placentas of women with healthy pregnancies and women with depression and treated with the SSRI fluoxetine during pregnancy. Twelve placentas of the Biology, Affect, Stress, Imaging and Cognition in Pregnancy and the Puerperium (BASIC) project were selected for RNA sequencing to examine differentially expressed genes: six male infants and six female infants, equally distributed over women treated with SSRI and without SSRI treatment. Our results show that more genes in the placenta of male infants show changed expression associated with fluoxetine treatment than in placentas of female infants, stressing the importance of sex-specific analyses. In addition, we identified genes related to extracellular matrix organization to be significantly enriched in placentas of male infants born to women treated with fluoxetine. It remains to be established whether the differentially expressed genes that we found to be associated with SSRI treatment are the result of the SSRI treatment itself, the underlying depression, or a combination of the two.