Perinatal bisphenol A exposure promotes dose-dependent alterations of the mouse methylome
ABSTRACT: Environmental factors during perinatal development influence developmental plasticity and disease susceptibility via alterations to the epigenome. Developmental exposure to the endocrine active compound, bisphenol A (BPA), has previously been associated with altered methylation at candidate gene loci. Here, we undertake the first genome-wide characterization of DNA methylation profiles in the liver of murine offspring perinatally exposed to multiple doses of BPA through the maternal diet. Using a tiered focusing approach, our strategy proceeds from unbiased broad DNA methylation analysis using methylation-based next generation sequencing technology to in-depth quantitative site-specific CpG methylation determination using the Sequenom EpiTYPER MassARRAY platform to profile liver DNA methylation patterns in offspring maternally exposed to BPA during gestation and lactation to doses ranging from 0 BPA/kg (Ctr), 50 µg BPA/kg (UG), or 50 mg BPA/kg (MG) diet (N=4 per group). Genome-wide analyses indicate non-monotonic effects of DNA methylation patterns following perinatal exposure to BPA, corroborating previous studies using multiple doses of BPA with non-monotonic outcomes. We observed enrichment of regions of altered methylation (RAMs) within CpG island (CGI) shores, but little evidence of RAM enrichment in CGIs. An analysis of promoter regions identified several hundred novel BPA-associated methylation events, and methylation alterations in the Myh7b and Slc22a12 gene promoters were validated. Using the Comparative Toxicogenomics Database, a number of candidate genes that have previously been associated with BPA-related gene expression changes were identified, and gene set enrichment testing identified epigenetically dysregulated pathways involved in metabolism and stimulus response. In this study, non-monotonic dose dependent alterations in DNA methylation among BPA-exposed mouse liver samples and their relevant pathways were identified and validated. The comprehensive methylome map presented here provides candidate loci underlying the role of early BPA exposure and later in life health and disease status. For this study, liver DNA from a subset of a/a wild-type animals was analyzed for full methylome characteristics: 1) standard diet (Ctr, n = 4 offspring; 2 male and 2 female); 2) 50 µg BPA/kg diet (UG, n = 4 offspring; 2 male and 2 female); 3) 50 mg BPA/kg diet (MG, n = 4 offspring; 1 male and 3 female).
Project description:Maternal obesity can program metabolic syndrome in offspring but the mechanisms are not well characterized. Moreover, the consequences of maternal overnutrition in the absence of frank obesity remain poorly understood. This study aimed to determine the effects of maternal consumption of a high fat-sucrose diet on the skeletal muscle metabolic and transcriptional profiles of adult offspring. Female Sprague Dawley rats were fed either a diet rich in saturated fat and sucrose (HFD, 23.5% fat, 20% sucrose wt/wt) or a standard chow diet (NFD, 7% fat, 10% sucrose w/w) for the 3 weeks prior to mating and throughout pregnancy and lactation. Although maternal weights were not different between groups at conception or weaning, HFD dams were ~22% heavier than chow fed dams from mid-pregnancy until 4 days post-partum. Adult male offspring of HFD dams were not heavier than controls but demonstrated features of insulin resistance including elevated plasma insulin concentration (+40%, P<0.05). Next Generation mRNA Sequencing was used to identify differentially expressed genes in the soleus muscle of offspring, and Gene Set Enrichment Analysis (GSEA) to detect coordinated changes that are characteristic of a biological function. GSEA identified 15 pathways enriched for up-regulated genes, including cytokine signaling (P<0.005), starch and sucrose metabolism (P<0.017), and inflammatory response (P<0.024). A further 8 pathways were significantly enriched for down-regulated genes including oxidative phosphorylation (P<0.004) and electron transport (P<0.022). Western blots confirmed a ~60% reduction in the phosphorylation of the insulin signaling protein Akt (P<0.05) and ~70% reduction in mitochondrial complexes II (P<0.05) and V expression (P<0.05). On a normal diet, offspring of HFD dams developed an insulin resistant phenotype, with transcriptional evidence of muscle cytokine activation, inflammation and mitochondrial dysfunction. These data indicate that maternal overnutrition, even in the absence of pre-pregnancy obesity can promote metabolic dysregulation and predispose offspring to type 2 diabetes. Messenger RNA profile of skeletal muscle of male offspring from female Sprague Dawley rats fed either a diet rich in saturated fat and sucrose (HFD, 23.5% fat, 20% sucrose wt/wt) or a standard chow diet (NFD, 7% fat, 10% sucrose w/w) for the 3 weeks prior to mating and throughout pregnancy and lactation. There were 5 HFD samples compared to 6 NFD control samples.
Project description:Objective: Procyanidins are polyphenolic bioactive compounds that exert beneficial effects against obesity and its related diseases. The aim of this study was to evaluate whether the supplementation with low doses of a grape seed procyanidin extract (GSPE) to dams during pre and postnatal periods has biological effects on their offspring at youth. Design: The metabolic imprinting effect of GSPE was evaluated in 30 days-old male offspring of four groups of rats that were fed either a standard diet (STD) or a high-fat diet (HFD) and supplemented with either GSPE at 25 mg per kg of body weight/day or vehicle during pregnancy and lactation. Results: A significant increase in the adiposity index and in the weight of all the white adipose tissue depots studied (retroperitoneal –RWAT-, mesenteric –MWAT-, epididymal –EWAT- and inguinal –IWAT-) was observed in offspring of dams fed with a HFD and treated with GSPE (HFT group), compared to the offspring of dams fed with the same diet and that do not received procyanidins (HF group). HFT animals also showed a higher number of cells in the EWAT, a sharply decrease of the circulating levels of monocyte chemoattractant protein-1 (MCP-1) as well as a moderate, but significant, decrease of plasma glycerol levels. The transcriptomic analysis performed in the EWAT showed 238 genes differentially expressed between HF and HFT animals, covering an entire range of processes related with the immune function and the inflammatory response (the metabolic pathway mainly reflected in the EWAT), adipose tissue remodeling and function, lipid and glucose homeostasis and metabolism of methyl groups. Conclusion: GSPE treatment to dams fed a HFD during pregnancy and lactation increases adiposity, decreases the circulating levels of MCP-1 and modulates the expression of key genes involved in the adipose tissue metabolism of their offspring. The microarray study was performed with the EWAT RNA samples of rats from the HF and the HFT groups (n=8 animals each).
Project description:Background: Consumption of high fat diets has negative impacts on health and well-being, some of which may be epigenetically regulated. Selenium and folate are two compounds which influence epigenetic mechanisms. We investigated the hypothesis that post-weaning supplementation with adequate levels of selenium and folate in mouse offspring fed a high fat, low selenium and folate diet during gestation and lactation will lead to epigenetic changes of potential importance for long-term health. Female offspring of mothers fed the experimental diet were either maintained on this diet (HF-low-low), or weaned onto a high-fat diet with sufficient levels of selenium and folate (HF-low-suf), for 8 weeks. Gene and protein expression, DNA methylation, and histone modifications were measured in colon and liver of female offspring. Results: Adequate levels of selenium and folate post-weaning affected gene expression in colon and liver of offspring, including decreasing Slc2a4 gene expression. Protein expression was only altered in the liver. There was no effect of adequate levels of selenium and folate on global histone modifications in the liver. Global liver DNA methylation was decreased in mice switched to adequate levels of selenium and folate, but there was no effect on methylation of specific CpG sites within the Slc2a4 gene in liver. Conclusions: Post-weaning supplementation with adequate levels of selenium and folate in female offspring of mice fed high-fat diets during gestation and lactation can alter global DNA methylation in liver. This may be one mechanism by which the negative effects of a poor diet during early life can be ameliorated. Further research is required to establish what role epigenetic changes play in mediating observed changes in gene and protein expression, and the relevance of these changes to health. Female wild type C57BL/6 mice (Animal Resource Centre, Western Australia) were fed a High Fat diet containing low levels of selenium and folate (HF-Low) for 7 days prior to mating with male C57BL/6 mice (Ruakura Small Animal Facility, Hamilton, New Zealand). Mothers were maintained on the HF-Low diet throughout gestation and lactation. Offspring of these female mice were randomly assigned to one of two different dietary treatments: either the same diet as the mothers (HF-Low), or a High Fat diet containing adequate selenium and folate (HF-Suf). At 12 weeks of age, mice were euthanized and colon and liver samples taken for microarray, proteomics, and DNA methylation analyses. Genomic DNA, total RNA and protein from whole colon and liver tissue was extracted using an AllPrep® DNA/RNA/Protein mini kit (Qiagen, Cat number 80004). Colon and liver RNA from six female offspring on the HF-Low diet was compared with colon and liver RNA from six female offspring on the HF-Suf diet. All individual RNA samples were hybridized against a common reference RNA on separate arrays. The reference RNA was prepared by pooling in equimolar proportions RNA extracted from the intestine and liver of twelve female C57BL/6 mice, these being all of the mice from which samples were derived for microarray analysis in the current study.
Project description:Though obesity is a global epidemic, the physiological mechanisms involved are little understood. Recent advances reveal that susceptibility to obesity can be programmed by maternal and neonatal nutrition. Specifically, a maternal low protein diet during pregnancy causes decreased intrauterine growth, rapid postnatal catch-up growth and increased risk for diet-induced obesity. Given that the synthesis of the neurotransmitter 5-hydroxytryptamine (5-HT) is nutritionally regulated and 5-HT is a trophic factor, we hypothesized that maternal diet influences fetal 5-HT exposure, which then influences central appetite network development and the subsequent efficacy of 5-HT to control energy balance in later life. Consistent with our hypothesis, pregnant low protein fed rat mothers exhibited elevated serum 5-HT, which was also evident in the placenta and fetal brains at E16.5. This increase was associated with reduced hypothalamic expression of 5-HT2CR - the primary 5-HT receptor influencing appetite. As expected, reduced 5-HT2CR expression was associated with impaired sensitivity to 5-HT-mediated appetite suppression. 5-HT primarily achieves effects on appetite via 5-HT2CR stimulation of pro-opiomelanocortin (POMC) peptides within the arcuate nucleus of the hypothalamus (ARC). We reveal that 5-HT2ARs are also anatomically positioned to influence the activity of ARC POMC and that 5-HT2AR mRNA is increased in the hypothalamus of in utero growth restricted offspring that underwent rapid postnatal catch-up growth. Furthermore, these animals are more sensitive to 5-HT2AR agonist-induced appetite suppression. These findings may not only reveal a 5-HT-mediated mechanism underlying programming of obesity susceptibility but also provide a promising means to correct it, via a 5-HT2AR agonist treatment. The study was carried out using male Wistar rats (Rattus norvegicus). On postnatal day 3, two experimental groups of offspring were established: controls (offspring of control dams) and recuperated (offspring of dams fed a low-protein diet (8% protein, w/v), but nursed by control dams. The animals were fed with standard chow until 3 months of age where the brains were collected for transcriptomic profiling
Project description:Adult female Wistar rats (about 220g) obtained from a breeding colony were mated and fed either a protein sufficient (PS) or protein restricted (PR) diet (n = 6 per dietary group) during F0 pregnancy which provided an increase in energy of approximately 25% compared to the diet fed to the breeding colony (2018S). During lactation dams were fed AIN93G and litters were standardisied to 8 offspring within 24 hours of birth with a bias towards females. Offpsring were weaned onto AIN93M at postnatal day 28 and F1 and F2 females were mated on postnatal day 70 (n = 6 per F0 dietary group). F1 and F2 dams were fed the PS diet during pregnancy and AIN93G during lactation. Offspring were weaned onto AIN93M. On postnatal day 70 unmated female offspring were fasted for 12 hours then sacrificed for hepatic transcritpome analysis by microarray. Expression of 1,684 genes differed by at least 2 fold between adult female F1 offspring of F0 dams from both dietary groups. 1680 genes were altered in F2 offspring and 2,065 genes altered in F3 offspring. Expression of 113 genes was altered in all three generations. Of these, 47% showed directionally opposite differences between generations. Gene ontology analysis revealed clear differences in the pathways altered in each generation. F1 and F2 offspring of F0 dams fed a PR diet showed impaired fasting glucose homeostasis. Hepatic phosphoenolpyruvate carboxykinase (PEPCK) expression was elevated in F1 and F2 offspring from F0 PR dams, but decreased in F3, compared to PS offspring
Project description:Background: Epidemiological studies suggest an association between maternal obesity and adverse neurodevelopmental outcomes in offspring. Objective: To compare the global proteomic portrait in the cerebral cortex between mice born to mothers on a high-fat or control diet who themselves were fed a high-fat or control diet. Methods: Male mice born to dams fed a control (C) or high fat (H) diet four weeks before conception and during gestation and lactation were assigned to either C or H diet at weaning. Mice (n=24) were sacrificed at 19-weeks and their cerebral cortices were pooled into 8 samples and analysed using an iTRAQ based 2D LC-MS methodology. Results: A total of 6,695 proteins were identified and fully quantified (q<0.01). Approximately 10% of these proteins demonstrated a minimum of one Standard Deviation of regulation across all biological replicates in at least one of the experimental groups (CH, HC, HH) relative to the control (CC). Principal component analysis and hierarchical clustering analysis showed that mice clustered based on the diet of the mother and not their current diet. In silico bioinformatics analysis revealed that maternal high-fat diet was significantly associated with response to hypoxia/oxidative stress and apoptosis in the cerebral cortex of the adult offspring. Conclusion: Maternal high-fat diet was associated with distinct endophenotypic changes of the adult mouse cerebral cortex independent of the diet of the offspring. The identified modulated proteins could represent novel therapeutic targets for the prevention of neuropathological features resulting from maternal obesity.
Project description:Maternal diet is associated with the development of metabolism-related and other non-communicable diseases in offspring. Underlying mechanisms, functional profiles, and molecular markers are only starting to be revealed. Here, we explored the physiological and molecular impact of maternal Western-style diet on the liver of male and female offspring. C57BL/6 dams were exposed to either a low fat/low cholesterol diet (LFD) or a Western-style high fat/high cholesterol diet (WSD) for six weeks before mating, as well as during gestation and lactation. Dams and offspring were sacrificed at postnatal day 14, and body, liver, and blood parameters were assessed. The impact of maternal WSD on the pups' liver gene expression was characterised by whole-transcriptome microarray analysis. Exclusively male offspring had significantly higher body weight upon maternal WSD. In offspring of both sexes of WSD dams, liver and blood parameters, as well as hepatic gene expression profiles were changed. In total, 686 and 604 genes were differentially expressed in liver (p≤0.01) of males and females, respectively. Only 10% of these significantly changed genes overlapped in both sexes. In males, in particular alterations of gene expression with respect to developmental functions and processes were observed, such as Wnt/beta-catenin signalling. In females, mainly genes important for lipid metabolism, including cholesterol synthesis, were changed. We conclude that maternal WSD affects physiological parameters and induces substantial changes in the molecular profile of the liver in two-week-old pups. Remarkably, the observed biological responses of the offspring reveal pronounced sex-specificity. C57BL/6 dams were exposed to either a low fat/low cholesterol diet (LFD) or a Western-style high fat/high cholesterol diet (WSD) as six weeks pre-treatment before mating, as well as during gestation and lactation. Offspring were sacrificed at postnatal week two, livers were removed and RNA samples were subjected to gene expression profiling.
Project description:Studies have indicated that altered maternal micronutrients and vitamins influence the development and susceptibility of newborns to chronic diseases. Among these, folic acid (FA) plays a key role in the synthesis and repair of DNA, along with maintenance of epigenetic DNA methylation. Deficiency of FA has been associated with the pathogenesis of neural tube defects. Since FA can modulate DNA methylation and affect gene expression, we investigated the effect of gestational FA supplementation on the expression of genes in the offspring brain. Our results suggest that a maternal ten-fold increase in FA supplementation alters the expression and dysregulates a number of genes in the offspring brain, including many involved in development. While a number of genes that were dysregulated were common to both male and female pups, there were sex differences in gene expression changes. C57BL/6J female mice were separated into two groups of ten mice and supplemented with a custom diet. One week prior to mating the low-dose group of female mice were fed a custom AIN-93G amino acid–based diet (Research Diet, Inc. New-Brunswick, NJ), with FA at 0.4 mg/kg, while the high-dose group received FA at 4 mg/kg diet. Tissues from the cerebral hemisphere of three independent pups of same gender were pooled together. A total of three microarray gene expression studies have been performed (0.4mg/kg or 4mg/kg both male and female) and the mean was used for comparison.
Project description:C57BL/6J mice were from The Jackson Laboratory (Maine, USA) and were housed/caged and fed a standard chow diet until 6 weeks of age whereupon they were placed in one of 4 different dietary regimens for a period of 3 weeks prior to mating. Mice were housed under pathogen-free conditions of 21± 1°C, 40 to 60% humidity, and a 12 h-12 h light/dark cycle. The 4 diet regimens used in this study were:  ad lib Standard Chow (Control diet) with ad lib drinking water.  Ad lib Standard Chow, with ad lib drinking water containing 0.64 mg/ml (97 mg/Kg body weight) monosodium glutamate (MSG diet).  Ad lib Test Diet Purina 5001 with 20% 55-HFCS (5B4K, Purina, USA), and ad lib drinking water (HFCS diet).  Ad lib Purina 5001 with 20% 55-HFCS, and ad lib drinking water containing 0.64 mg/ml (97 mg/K body weight) monosodium glutamate (HFCS+MSG diet). See Table 1 for diet composition. Following mating, the 4 groups of dams were maintained on their respective diets throughout the gestation and nursing period. Male offspring used in these experiments were weighed, then weaned onto the same diets and maintained in this regimen until they reached either 16 or 32 weeks of age. Total RNA was prepared from the liver and visceral white adipose tissue (WAT) taken from 16-week-old mice in the 4 different diet groups using Qiagen RNeasy Kit (Qiagen USA) according to the manufacturers instructions and stored at -80 o C.<br>
Project description:Background & Aims: The influences of the maternal diet during gestation has been suggested to be involved in the development of different aspects of the metabolic syndrome. In our mouse model we characterised the role of maternal western diet in the development of non-alcoholic fatty liver disease (NAFLD) in the offspring. Methods: Female mice were fed either a western (W) or low-fat control (L) semi-synthetic diet before and during gestation and lactation. At weaning, male offspring were assigned either the W or the L diet, generating four experimental groups: WW, WL, LW and LL offspring. Biochemical, histological and epigenetic indicators were investigated at 29 weeks of age. Results: Male offspring exposed to prenatal western style diet and to a post-weaning W diet (WW) showed hepatomegaly combined with increased hepatic cholesterol and triglycerides accumulation, compared to LW offspring. This was associated with up-regulation of de novo lipid synthesis and dysregulation of beta oxidation and lipid storage. Elevated hepatic transaminases and increased expression of Tnfa, Cd11, Mcp1 and Tgfb underpin the severity of liver injury. Histological analysis supported the presence of steatohepatitis in the WW offspring. In addition alterations in DNA methylation in key metabolic genes (Ppara, Insig, Fasn) were detected. Conclusion: Maternal dietary fat intake during critical developmental phases programs susceptibility to liver disease in mouse offspring. This was mediated by shifts in lipid metabolism and inflammatory response. Long lasting epigenetic changes may underlie this dysregulation 4 groups of 6 male mouse were analysed , 1 experimental and 1 biological outlier was excluded , so n=6,5,5,6 in the 4 groups (LL,LW,WL,WW)