Project description:DNA methylation profiles from saliva collected from 89 mothers and 179 adolescent children who received or did not receive perinatal folic acid supplementation Periconceptional folic acid supplementation and DNA methylation patterns in adolescents
Project description:Folate, a water-soluble vitamin, is a key source of one-carbon groups for DNA methylation, but studies of the DNA methylation response to supplemental folic acid yield inconsistent results. The aim of this study was to determine if DNA methylation patterns in the dominant white blood cell type, neutrophils, would respond differently than whole blood in response to chronic folic acid supplementation. Saliva and blood methylation was clearly distinguishable though there was positive correlation overall. There was little correlation in CpG sites within relevant candidate genes. Correlated CpG sites were more likely to occur in areas of low CpG density (i.e. CpG shores and open seas). There was more variability in CpG sites from saliva than blood, which may reflect its heterogeneity. Thus, this study provides a framework for using DNA methylation from saliva and suggests that DNA methylation of saliva may offer distinct opportunities for epidemiological and longitudinal studies of psychiatric traits. DNA methylation was assessed in whole blood and CD16+ neutrophils from obese and normal weight adult women undergoing 8 weeks of folate supplementation. Blood was collected in EDTA vacuum tubes, and CD16+ nutrophils were isolated by positive selection with Dynabeads. DNA was extracted using the DNeasy Kit (Qiagen). DNA methylation was interrogated for each sample using the HumanMethylation450 BeadChip (Illumina).
Project description:Folic acid supplements prior to and during gestation are recommended and necessary to prevent neural tube defects in developing embryos. But there are also studies suggesting possible adverse effects of high-dose folic acid supplementation. Here, we address whether maternal dietary folic acid supplementation at 40 mg/kg chow (FD), restricted to a period prior to conception, affects gene expression in the offspring generation.
Project description:STUDY QUESTION: Could clinically-relevant moderate and/or high dose maternal folic acid supplementation prevent aberrant developmental and epigenetic outcomes associated with assisted reproductive technologies (ART)? SUMMARY ANSWER: Our results demonstrate dose-dependent and sex-specific effects of folic acid supplementation in ART and provide evidence that moderate dose supplements may be optimal for both sexes. WHAT IS KNOWN ALREADY: Children conceived using ART are at an increased risk for growth and genomic imprinting disorders, often associated with DNA methylation defects. Folic acid supplementation is recommended during pregnancy to prevent adverse offspring outcomes; however, the effects of folic acid supplementation in ART remain unclear. STUDY DESIGN, SIZE, DURATION: Outbred female mice were fed 3 folic-acid supplemented diets, control (rodent daily recommended intake or DRI; CD), moderate (4-fold DRI; 4FASD) or high (10-fold DRI; 10FASD) dose, for six weeks prior to ART and throughout gestation. Mouse ART involved a combination of superovulation, in vitro fertilization, embryo culture and embryo transfer. PARTICIPANTS/MATERIALS, SETTING, METHODS: Upon collection of midgestation embryos and placentas (n=74-99 embryos/group), all embryos were assessed for developmental delay and gross morphological abnormalities. Embryos and placentas were also examined at the epigenetic level. We assessed methylation at four imprinted genes (Snrpn, Kcnq1ot1, Peg1, and H19) in matched midgestation embryos and placentas (n=31-32/group) using bisulfite pyrosequencing. In addition, we examined genome-wide DNA methylation patterns in midgestation placentas (n=6 normal placentas per sex/group) and embryos (n=6 normal female embryos/group; n=3 delayed female embryos/group) using reduced representation bisulfite sequencing. MAIN RESULTS AND THE ROLE OF CHANCE: Moderate, but not high dose supplementation, was associated with a decrease in the proportion of developmentally delayed embryos. Although moderate dose folic acid supplementation reduced DNA methylation variance at certain imprinted genes in embryonic and placental tissues, high dose supplementation exacerbated the negative effects of ART at imprinted loci. Furthermore, folic acid supplements resolved female-biased aberrant imprinted gene methylation. Supplementation was more effective at correcting ART-induced genome-wide methylation defects in male versus female placentas; however, folic acid supplementation also led to additional methylation perturbations which were far more pronounced in males. LIMITATIONS, REASONS FOR CAUTION: Although the combination of mouse ARTs utilized in this study consisted of techniques commonly used in human fertility clinics, there may be species differences. Therefore, human studies, designed to determine the optimal levels of folic acid supplementation for ART pregnancies, and taking into account fetal sex, are warranted. WIDER IMPLICATIONS OF THE FINDINGS: Taken together, our findings support moderation in the dose of folic acid supplements taken during ART.
Project description:To prove our hypothesis that excess folic acid supplementation is responsible for widespread gene expression changes during gestational development that may be responsible for abnormal behaviors later on in the life, we have used whole genome microarray expression profiling in lymphoblstoid cells as a proof of concept. Human lymphoblastoid cells in culture were supplemented with folic acid, and four days later gene expression changes were measured. Expression of three genes (FMR1, GPR37L1 and TSSK3) from this data was confirmed by Western blot analyses. Dysregulation of other genes (ARHGAP6, EF1A1, MEST, SMAD3) was confirmed by qRT-PCR. Lymphoid cells at confluence were grown with or without folic acid for four days. Total mRNA was prepared and labeled with cyanine-3 (Cy3), followed by hybridization. RNA samples from three independent experiments were pooled.
Project description:The iTRAQ analysis combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed to separate differentially expressed placental proteins from 4 pregnant women with ICP and 4 healthy pregnant women.
Project description:Dietary folate is a major source of methyl groups required for DNA methylation, an epigenetic modification that is actively maintained and remodelled during spermatogenesis. While high dose folic acid supplementation (up to ten times the daily recommended dose) has been shown to improve sperm parameters in infertile men, the effects of supplementation on the sperm epigenome are unknown. To assess the impact of six months of high dose folic acid supplementation on the sperm epigenome, we studied 30 men with idiopathic infertility. Blood folate concentrations increased significantly after supplementation with no significant improvements in sperm parameters. Methylation levels of the differentially methylated regions of several imprinted loci (H19, DLK1/GTL2, MEST, SNRPN, PLAGL1, KCNQ1OT1) were normal both before and after supplementation. Reduced representation bisulfite sequencing (RRBS) revealed a significant global loss of methylation across different regions of the sperm genome. The most marked loss of DNA methylation was found in sperm from patients homozygous for the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism, a common polymorphism in a key enzyme required for folate metabolism. RRBS analysis also showed that most of the differentially methylated tiles were located in DNA repeats, low CpG density and intergenic regions. Ingenuity Pathway Analysis revealed that methylation of promoter regions was altered in several genes involved in cancer and neurobehavioral disorders including CBFA2T3, PTPN6, COL18A1, ALDH2, UBE4B, ERBB2, GABRB3, CNTNAP4 and NIPA1. Our data reveal alterations of the human sperm epigenome associated with high dose folic acid supplementation, effects that were exacerbated by a common polymorphism in MTHFR. Reduced representation bisulfite sequencing of 28 human sperm samples before and after 6 month of high dose folic acid supplementation.