Maternal Folic Acid Supplementation Mediates Offspring Health via DNA Methylation

The one-carbon metabolism as an underlying pathway for placental DNA methylation - a systematic review

Epigenetic modifications, including DNA methylation, are proposed mechanisms explaining the impact of parental exposures to foetal development and lifelong health. Micronutrients including folate, choline, and vitamin B12 provide methyl groups for the one-carbon metabolism and subsequent DNA methylation processes. Placental DNA methylation changes in response to one-carbon moieties hold potential targets to improve obstetrical care. We conducted a systematic review on the associations between one-carbon metabolism and human placental DNA methylation. We included 22 studies. Findings from clinical studies with minimal ErasmusAGE quality score 5/10 (n = 15) and in vitro studies (n = 3) are summarized for different one-carbon moieties. Next, results are discussed per study approach: (1) global DNA methylation (n = 9), (2) genome-wide analyses (n = 4), and (3) gene specific (n = 14). Generally, one-carbon moieties were not associated with global methylation, although conflicting outcomes were reported specifically for choline. Using genome-wide approaches, few differentially methylated sites associated with S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), or dietary patterns. Most studies taking a gene-specific approach indicated site-specific relationships depending on studied moiety and genomic region, specifically in genes involved in growth and development including LEP, NR3C1, CRH, and PlGF; however, overlap between studies was low. Therefore, we recommend to further investigate the impact of an optimized one-carbon metabolism on DNA methylation and lifelong health.

DNA methylation and its potential roles in common oral diseases

Oral diseases are among the most common diseases worldwide and are associated with systemic illnesses, and the rising occurrence of oral diseases significantly impacts the quality of life for many individuals. It is crucial to detect and treat these conditions early to prevent them from advancing. DNA methylation is a fundamental epigenetic process that contributes to a variety of diseases including various oral diseases. Taking advantage of its reversibility, DNA methylation becomes a viable therapeutic target by regulating various cellular processes. Understanding the potential role of this DNA alteration in oral diseases can provide significant advances and more opportunities for diagnosis and therapy. This article will review the biology of DNA methylation, and then mainly discuss the key findings on DNA methylation in oral cancer, periodontitis, endodontic disease, oral mucosal disease, and clefts of the lip and/or palate in the background of studies on global DNA methylation and gene-specific DNA methylation.

The Gut Microbial Regulation of Epigenetic Modification from a Metabolic Perspective

Obesity is a global health challenge that has received increasing attention in contemporary research. The gut microbiota has been implicated in the development of obesity, primarily through its involvement in regulating various host metabolic processes. Recent research suggests that epigenetic modifications may serve as crucial pathways through which the gut microbiota and its metabolites contribute to the pathogenesis of obesity and other metabolic disorders. Hence, understanding the interplay between gut microbiota and epigenetic mechanisms is crucial for elucidating the impact of obesity on the host. This review primarily focuses on the understanding of the relationship between the gut microbiota and its metabolites with epigenetic mechanisms in several obesity-related pathogenic mechanisms, including energy dysregulation, metabolic inflammation, and maternal inheritance. These findings could serve as novel therapeutic targets for probiotics, prebiotics, and fecal microbiota transplantation tools in treating metabolic disruptions. It may also aid in developing therapeutic strategies that modulate the gut microbiota, thereby regulating the metabolic characteristics of obesity.

A comprehensive review of the new FIGO classification of ovulatory disorders

BACKGROUND

The World Health Organization (WHO) system for the classification of disorders of ovulation was produced 50 years ago and, by international consensus, has been updated by the International Federation of Gynecology and Obstetrics (FIGO).

OBJECTIVE AND RATIONALE

This review outlines in detail each component of the FIGO HyPO-P (hypothalamic, pituitary, ovarian, PCOS) classification with a concise description of each cause, and thereby provides a systematic method for diagnosis and management.

SEARCH METHODS

We searched the published articles in the PubMed database in the English-language literature until October 2022, containing the keywords ovulatory disorders; ovulatory dysfunction; anovulation, and each subheading in the FIGO HyPO-P classification. We did not include abstracts or conference proceedings because the data are usually difficult to assess.

OUTCOMES

We present the most comprehensive review of all disorders of ovulation, published systematically according to the logical FIGO classification.

WIDER IMPLICATIONS

Improving the diagnosis of an individual's ovulatory dysfunction will significantly impact clinical practice by enabling healthcare practitioners to make a precise diagnosis and plan appropriate management.

Root Curvature in Non-Syndromic Oral Clefts: A Case-Control Study in a Brazilian Population

OBJECTIVE

This study assesses the degree of root curvature in patients with non-syndromic cleft lip and/or palate (NSCL/P).

DESIGN

Retrospective. Case-control study.

SETTING

Root curvature was assessed in lower premolars and molars in 800 panoramic radiographs: 400 from patients with cleft and 400 from healthy control individuals. Root curvature was classified according to its angulation, as well as its apical, medial, or coronal localization.

RESULTS

The frequency of mild curvature in the NSCL/P group compared to the control group was higher in premolars especially in the left second premolar in cleft palate (OR: 6.91; 95% CI: 3.23-14.77; P < .0001). The frequency of moderate curvature in molars was significantly higher in the cleft group, with the highest risk in the right first molar in the cleft lip group (OR: 2.74; 95% CI: 1.67-4.52; P < .0001). Inclination was more frequently observed in the apical third of the root in the group with cleft, whereas for the control group, the curvature was more frequent in the medial third. In patients with cleft, the OR of curvature in the apical third was significant in premolars (left lower second premolar: Cleft lip, OR: 1.91; 95% CI: 1.04-3.52; P = .03; right lower second premolar: Cleft lip, OR: 1.91, 95% CI: 1.04-3.50; P = .03, cleft lip and palate, OR: 1.75; 95% CI: 1.12-2.73; P = .01).

CONCLUSION

The results of the current study indicate differences in root curvature in patients with non-syndromic cleft lip and/or palate, which should be considered during the dental treatment planning of patients.

Perspectives on folate with special reference to epigenetics and neural tube defects

Folate is a micronutrient essential for DNA synthesis, cell division, fetal growth and development. Folate deficiency leads to genomic instability. Inadequate intake of folate during conception may lead to neural tube defects (NTDs) in the offspring. Folate influences the DNA methylation, histone methylation and homocysteine mediated gene methylation. DNA methylation influences the expression of microRNAs (miRNAs). Folate deficiency may be associated with miRNAs misregulation leading to NTDs. Mitochondrial epigenetics and folate metabolism has proved to be involved in embryogenesis and neural tube development. Folate related genetic variants also cause the occurrence of NTDs. Unmetabolized excessive folate may affect health adversely. Hence estimation of folate levels in the blood plays an important role in high-risk cases.

Maternal folic acid supplementation does not impact skeletal muscle function and metabolism in male and female CD-1 mouse offspring

Folic acid fortification of all white flour, enriched pasta, and cornmeal products became mandatory in Canada to reduce risk of neural tube defects at birth. Furthermore, Health Canada and the Society of Obstetricians and Gynaecologists of Canada recommend women take daily prenatal folic acid supplements in addition to folic acid fortified foods during pregnancy. However, the influence of maternal folic acid supplementation on offspring development, specifically the highly abundant and metabolically active skeletal muscle, is currently unknown. Thus, the purpose of this study was to determine the effect of supplemental folic acid (four times higher than normal dietary consumption), in utero and throughout suckling on muscle size, function, and metabolism in male and female CD-1 mouse offspring. The major findings were that maternal exposure to supplemental folic acid (i) had no impact on postpartum growth rates or muscle mass in female and male offspring, (ii) had no impact on skeletal muscle contractile kinetics in females and male offspring, and (iii) increased maximal phosphofructokinase activity in extensor digitorum longus of female and male offspring. These findings suggest that exposure to folic acid supplementation in utero and throughout suckling at levels four times higher than recommended had minimal effect on skeletal muscle size, function, and metabolism regardless of sex. Future research is needed explore the underlying biological pathways and mechanisms affected by folic acid supplementation during pregnancy and lactation on offspring skeletal muscle tissue, specifically in humans.

Epigenetic Genome Modifications during Pregnancy: The Impact of Essential Nutritional Supplements on DNA Methylation

Pregnancy is an extremely stressful period in a pregnant woman's life. Currently, women's awareness of the proper course of pregnancy and its possible complications is constantly growing. Therefore, a significant percentage of women increasingly reach for various dietary supplements during gestation. Some of the most popular substances included in multi-ingredient supplements are folic acid and choline. Those substances are associated with positive effects on fetal intrauterine development and fewer possible pregnancy-associated complications. Recently, more and more attention has been paid to the impacts of specific environmental factors, such as diet, stress, physical activity, etc., on epigenetic modifications, understood as changes occurring in gene expression without the direct alteration of DNA sequences. Substances such as folic acid and choline may participate in epigenetic modifications by acting via a one-carbon cycle, leading to the methyl-group donor formation. Those nutrients may indirectly impact genome phenotype by influencing the process of DNA methylation. This review article presents the current state of knowledge on the use of folic acid and choline supplementation during pregnancy, taking into account their impacts on the maternal-fetal unit and possible pregnancy outcomes, and determining possible mechanisms of action, with particular emphasis on their possible impacts on epigenetic modifications.

Emerging Functional Connections Between Metabolism and Epigenetic Remodeling in Neural Differentiation

Stem cells possess extraordinary capacities for self-renewal and differentiation, making them highly valuable in regenerative medicine. Among these, neural stem cells (NSCs) play a fundamental role in neural development and repair processes. NSC characteristics and fate are intricately regulated by the microenvironment and intracellular signaling. Interestingly, metabolism plays a pivotal role in orchestrating the epigenome dynamics during neural differentiation, facilitating the transition from undifferentiated NSC to specialized neuronal and glial cell types. This intricate interplay between metabolism and the epigenome is essential for precisely regulating gene expression patterns and ensuring proper neural development. This review highlights the mechanisms behind metabolic regulation of NSC fate and their connections with epigenetic regulation to shape transcriptional programs of stemness and neural differentiation. A comprehensive understanding of these molecular gears appears fundamental for translational applications in regenerative medicine and personalized therapies for neurological conditions.

Molecular nutrition in life course perspective: Pinpointing metabolic pathways to target during periconception

Lifecourse nutrition encompasses nourishment from early development into parenthood. From preconception and pregnancy to childhood, late adolescence, and reproductive years, life course nutrition explores links between dietary exposures and health outcomes in current and future generations from a public health perspective, usually addressing lifestyle behaviours, reproductive well-being and maternal-child health strategies. However, nutritional factors that play a role in conceiving and sustaining new life might also require a molecular perspective and recognition of critical interactions between specific nutrients and relevant biochemical pathways. The present perspective summarises evidence about the links between diet during periconception and next-generation health and outlines the main metabolic networks involved in nutritional biology of this sensitive time frame.

Uncovering the Hidden Dangers and Molecular Mechanisms of Excess Folate: A Narrative Review

This review delves into the intricate relationship between excess folate (vitamin B9) intake, especially its synthetic form, namely, folic acid, and its implications on health and disease. While folate plays a pivotal role in the one-carbon cycle, which is essential for DNA synthesis, repair, and methylation, concerns arise about its excessive intake. The literature underscores potential deleterious effects, such as an increased risk of carcinogenesis; disruption in DNA methylation; and impacts on embryogenesis, pregnancy outcomes, neurodevelopment, and disease risk. Notably, these consequences stretch beyond the immediate effects, potentially influencing future generations through epigenetic reprogramming. The molecular mechanisms underlying these effects were examined, including altered one-carbon metabolism, the accumulation of unmetabolized folic acid, vitamin-B12-dependent mechanisms, altered methylation patterns, and interactions with critical receptors and signaling pathways. Furthermore, differences in the effects and mechanisms mediated by folic acid compared with natural folate are highlighted. Given the widespread folic acid supplementation, it is imperative to further research its optimal intake levels and the molecular pathways impacted by its excessive intake, ensuring the health and well-being of the global population.

Associations of MTHFR Polymorphisms and Cytosine Modifications with Early-Gestational Diabetes Mellitus in Chinese Pregnant Women

Early-Gestational Diabetes Mellitus (Early-GDM) is a complex condition that may cause complications in infants of affected mothers. The aim of this case-control study was to analyze the effects of genetic-epigenetic interaction on Early-GDM and fetal development with respect to cytosine modifications (i.e., 5mC, 5-methylcytosines; and 5hmC, 5-hydroxymethylcytosines) and single nucleotide polymorphisms (SNPs) of MTHFR, a key gene involving cytosine modifications. Peripheral blood samples were collected from 92 women in their first or second trimester of pregnancy (Early-GDM, n = 14; Controls, n = 78). Global DNA 5mC and 5hmC were quantified by HPLC-MS/MS, and MTHFR SNPs (rs1801133 C > T and rs1801131 A > C) were determined by TaqMan-qPCR. Association analysis suggested that MTHFR rs1801133 TT genotype was a risk factor of Early-GDM (OR [odds ratio] = 4.00; 95% CI [confidence interval]: 1.24, 12.86; p = 0.02). The C allele of rs1801131 appeared to be a protective factor for the 2-h OGTT (oral glucose tolerance test) (OR = -0.79; 95% CI: -1.48, -0.10; p = 0.03). Patients with Early-GDM had higher global 5mC and lower global 5hmC. The reduction of global 5hmC and the TT genotype of rs1801133 were associated with higher level of the 1st-FBG (fasting blood glucose in the first trimester) (p < 0.05). Additionally, global 5mC showed a positive correlation with birth weight, body length and head circumference of newborns, while global 5hmC showed a negative correlation with birth weight. The current study implicated MTHFR SNPs and cytosine modifications in the development of Early-GDM and potential complications in their newborns.

Myelomeningocele: the evolution of care over the last 50 years

PURPOSE

Myelomeningocele (MMC) is one of the representative anomalies in the field of pediatric neurosurgery. During the 50 years of ISPN history, MMC had a tremendous changes in its incidence, clinical management and outcome with advanced understanding of its pathogenesis. We reviewed the changes in MMC during the period.

METHODS

We reviewed the literature review and collected our experiences.

RESULTS

During the 50 years, major changes happened in many aspects of MMC including incidence, pathoembryogenesis, folate deficiency, prevention, prenatal diagnosis, mode of delivery, treatment policy with ethical considerations, clinical treatment including fetal surgery, latex allergy, retethering, management outcome, multidisciplinary team approach, and socioeconomic and family issues.

CONCLUSIONS

There was a great advance in the management and research of MMC during the 50 years. It is a monumental achievement of pediatric neurosurgeons and colleagues of the related fields.

Effect of Low Dietary Folate on Mouse Spermatogenesis and Spindle Assembly Checkpoint Dysfunction May Contribute to Folate Deficiency-Induced Chromosomal Instability in Cultured Mouse Spermatogonia

Folate, as the initial substrate in one-carbon metabolism, is involved in the synthesis of important substances such as DNA, RNA, and protein. Folate deficiency (FD) is associated with male subfertility and impaired spermatogenesis, yet the underlying mechanisms are poorly understood. In the present study, we established an animal model of FD to investigate the effect of FD on spermatogenesis. GC-1 spermatogonia were used as a model to investigate the effect of FD on proliferation, viability, and chromosomal instability (CIN). Furthermore, we explored the expression of core genes and proteins of spindle assembly checkpoint (SAC), a signaling cascade ensuring accurate chromosome segregation and preventing CIN during mitosis. Cells were maintained in medium containing 0, 20, 200, or 2000 nM folate for 14 days. CIN was measured by using a cytokinesis-blocked micronucleus cytome assay. We found that sperm counts decreased significantly (p < 0.001) and the rate of sperm with defects in the head increased significantly (p < 0.05) in FD diet mice. We also found, relative to the folate-sufficient conditions (2000 nM), cells cultured with 0, 20, or 200 nM folate exhibited delayed growth and increased apoptosis in an inverse dose-dependent manner. FD (0, 20, or 200 nM) significantly induced CIN (p < 0.001, p < 0.001, and p < 0.05, respectively). Moreover, FD significantly and inverse dose dependently increased the mRNA and protein expression of several key SAC-related genes. The results indicate that FD impairs SAC activity, which contributes to mitotic aberrations and CIN. These findings establish a novel association between FD and SAC dysfunction. Thus, FD-impaired spermatogenesis may be partly due to genomic instability and proliferation inhibition of spermatogonia.

Effects of folic acid and folic acid plus zinc supplements on the sperm characteristics and pregnancy outcomes of infertile men: A systematic review and meta-analysis

Background

Folic acid and zinc supplements have been used to treat male infertility, but their efficacy is still debated.

Objective

To systematically evaluate the effects of folic acid and folic acid plus zinc supplements on sperm characteristics and pregnancy outcomes of infertile men.

Methods

An online systematic search was performed using PubMed, Cochrane Library, and EMBASE databases from inception to August 1, 2022. The goal was to identify randomized controlled trials (RCTs) that used folic acid or folic acid plus zinc to improve sperm characteristics of infertile men. Data were extracted by two investigators who independently screened the literature and assessed for quality according to the criteria. The meta-analysis was performed using RevMan 5.4 software.

Results

A total of 8 RCT studies involving 2168 patients were included. The results showed that compared with the controls, folic acid significantly increased sperm motility (MD, 3.63; 95% CI, -1.22 to 6.05; P = 0.003), but did not affect the sperm concentration (MD, 2.53; 95% CI, -1.68 to 6.73; P = 0.24) and sperm morphology (MD, -0.02; 95% CI, -0.29 to 0.24; P = 0.86) in infertile men. Folic acid plus zinc did not affect sperm concentration (MD, 1.87; 95% CI, -1.39 to 5.13; P = 0.26), motility (MD, 1.67; 95% CI, -1.29 to 4.63; P = 0.27), and morphology (MD, -0.05; 95% CI, -0.27 to 0.18; P = 0.69) in infertile men. Secondary results showed that compared with a placebo, folic acid alone had a higher rate of pregnancy in transferred embryos (35.6% vs. 20.4%, P = 0.082), but the difference was not significant. Folic acid plus zinc did not affect pregnancy outcomes.

Conclusions

Based on the meta-analysis, no significant improvements in sperm characteristics with folic acid plus zinc supplements were seen. However, folic acid alone has demonstrated the potential to improve sperm motility and in vitro fertilization-intracytoplasmic sperm injection (IVF-ICSI) outcomes. This indicates that folic acid supplements alone may be a viable treatment option for male infertility.

Does maternal genetic liability to folate deficiency influence the risk of antiseizure medication-associated language impairment and autistic traits in children of women with epilepsy?

BACKGROUND

Prenatal exposure to antiseizure medication (ASM) may lead to low plasma folate concentrations and is associated with impaired neurodevelopment.

OBJECTIVE

To examine whether maternal genetic liability to folate deficiency interacts with ASM-associated risk of language impairment and autistic traits in children of women with epilepsy.

METHODS

We included children of women with and without epilepsy and with available genetic data enrolled in the Norwegian Mother, Father, and Child Cohort Study (MoBa). Information on ASM use, folic acid supplement use and dose, dietary folate intake, child autistic traits, and child language impairment was obtained from parent-reported questionnaires. Using logistic regression, we examined the interaction between prenatal ASM exposure and maternal genetic liability to folate deficiency expressed as polygenic risk score (PRS) of low folate concentrations or maternal rs1801133 genotype (CC or CT/TT) on risk of language impairment or autistic traits.

RESULTS

We included 96 children of women with ASM-treated epilepsy, 131 children of women with ASM-untreated epilepsy, and 37,249 children of women without epilepsy. The PRS of low folate concentrations or the maternal rs1801133 genotype did not interact with the ASM-associated risk of language impairment or autistic traits in ASM-exposed children of women with epilepsy compared to ASM-unexposed children aged 1.5-8 years. ASM-exposed children had increased risk of adverse neurodevelopment regardless of maternal rs1801133 genotype (adjusted odds ratio (aOR) for language impairment age 8 years was 2.88 (95% confidence interval (CI) 1.00-8.26) if CC and aOR 2.88 (CI 1.10-7.53) if CT/TT genotypes). In children of women without epilepsy aged 3 years, those with maternal rs1801133 CT/TT compared to CC genotype had increased risk of language impairment (aOR 1.18, CI 1.05-1.34).

CONCLUSIONS

In this cohort of pregnant women reporting widespread use of folic acid supplements, maternal genetic liability to folate deficiency did not significantly influence the ASM-associated risk of impaired neurodevelopment.

Effects of folic acid supplementation in pregnant mice on glucose metabolism disorders in male offspring induced by lipopolysaccharide exposure during pregnancy

The DOHaD theory suggests that adverse environmental factors in early life may lead to the development of metabolic diseases including diabetes and hypertension in adult offspring through epigenetic mechanisms such as DNA methylation. Folic acid (FA) is an important methyl donor in vivo and participates in DNA replication and methylation. The preliminary experimental results of our group demonstrated that lipopolysaccharide (LPS, 50 µg/kg/d) exposure during pregnancy could lead to glucose metabolism disorders in male offspring, but not female offspring; however, the effect of folic acid supplementation on glucose metabolism disorders in male offspring induced by LPS exposure remains unclear. Therefore, in this study, pregnant mice were exposed to LPS on gestational day (GD) 15-17 and were given three doses of FA supplementation (2 mg/kg, 5 mg/kg, or 40 mg/kg) from mating to lactation to explore its effect on glucose metabolism in male offspring and the potential mechanism. This study confirmed that FA supplementation of 5 mg/kg in pregnant mice improved glucose metabolism in LPS-exposed offspring during pregnancy by regulating gene expression.

The impact of epigenetic landscape on ovarian cells in infertile older women undergoing IVF procedures

The constant decline in fertility and older reproductive age is the major cause of low clinical pregnancy rates in industrialised countries. Epigenetic mechanisms impact on proper embryonic development in women undergoing in vitro fertilisation (IVF) protocols. Here, we describe the main epigenetic modifications that may influence female reproduction and could affect IVF success.

Epigenetic Mechanisms Involved in the Effects of Maternal Hyperhomocysteinemia on the Functional State of Placenta and Nervous System Plasticity in the Offspring

According to modern view, susceptibility to diseases, specifically to cognitive and neuropsychiatric disorders, can form during embryonic development. Adverse factors affecting mother during the pregnancy increase the risk of developing pathologies. Despite the association between elevated maternal blood homocysteine (Hcy) and fetal brain impairments, as well as cognitive deficits in the offspring, the role of brain plasticity in the development of these pathologies remains poorly studied. Here, we review the data on the negative impact of hyperhomocysteinemia (HHcy) on the neural plasticity, in particular, its possible influence on the offspring brain plasticity through epigenetic mechanisms, such as changes in intracellular methylation potential, activity of DNA methyltransferases, DNA methylation, histone modifications, and microRNA expression in brain cells. Since placenta plays a key role in the transport of nutrients and transmission of signals from mother to fetus, its dysfunction due to aberrant epigenetic regulation can affect the development of fetal CNS. The review also presents the data on the impact of maternal HHcy on the epigenetic regulation in the placenta. The data presented in the review are not only interesting from purely scientific point of view, but can help in understanding the role of HHcy and epigenetic mechanisms in the pathogenesis of diseases, such as pregnancy pathologies resulting in the delayed development of fetal brain, cognitive impairments in the offspring during childhood, and neuropsychiatric and neurodegenerative disorders later in life, as well as in the search for approaches for their prevention using neuroprotectors.

Abnormal methylation caused by folic acid deficiency in neural tube defects

Neural tube closure disorders, including anencephaly, spina bifida, and encephalocele, cause neural tube defects (NTDs). This congenital disability remained not only a major contributor to the prevalence of stillbirths and neonatal deaths but also a significant cause of lifelong physical disability in surviving infants. NTDs are complex diseases caused by multiple etiologies, levels, and mechanisms. Currently, the pathogenesis of NTDs is considered to be associated with both genetic and environmental factors. Here, we aimed to review the research progress on the etiology and mechanism of NTDs induced by methylation modification caused by folic acid deficiency. Folic acid supplementation in the diet is reported to be beneficial in preventing NTDs. Methylation modification is one of the most important epigenetic modifications crucial for brain neurodevelopment. Disturbances in folic acid metabolism and decreased S-adenosylmethionine levels lead to reduced methyl donors and methylation modification disorders. In this review, we summarized the relationship between NTDs, folic acid metabolism, and related methylation of DNA, imprinted genes, cytoskeletal protein, histone, RNA, and non-coding RNA, so as to clarify the role of folic acid and methylation in NTDs and to better understand the various pathogenesis mechanisms of NTDs and the effective prevention.

As3MT-mediated SAM consumption, which inhibits the methylation of histones and LINE1, is involved in arsenic-induced male reproductive damage

Studies have demonstrated that arsenic (As) induces male reproductive injury, however, the mechanism remains unknown. The high levels of arsenic (3) methyltransferase (As3MT) promote As-induced male reproductive toxicity. For As-exposed mice, the germ cells in seminiferous tubules and sperm quality were reduced. Exposure to As caused lower S-adenosylmethionine (SAM) and 5-methylcytosine (5 mC) levels, histone and DNA hypomethylation, upregulation of long interspersed element class 1 (LINE1, or L1), defective repair of double-strand breaks (DSBs), and the arrest of meiosis, resulting in apoptosis of germ cells and lower litter size. For GC-2spd (GC-2) cells, As induced apoptosis, which was prevented by adding SAM or by reducing the expression of As3MT. The levels of LINE1, affected by SAM content, were involved in As-induced apoptosis. Furthermore, folic acid (FA) and vitamin B12 (VB₁₂) supplements restored SAM, 5 mC, and LINE1 levels and blocked impairment of spermatogenesis and testes and lower litter size. Exposed to As, mice with As3MT knockdown showed less impairment of spermatogenesis and testes and greater litter size compared to As-exposed wild-type (WT) mice. Thus, the high As3MT levels induced by As consume SAM and block histone and LINE1 DNA methylation, elevating LINE1 expression and evoking impairment of spermatogenesis, which causes male reproductive damage. Overall, we have found a mechanism for As-induced male reproductive damage, which provides biological insights into the alleviation of reproductive injury induced by environmental factors.

Alterations in DNA Methylation in Orofacial Clefts

Orofacial clefts are among the most common craniofacial anomalies with multifactorial etiologies, including genetics and environments. DNA methylation, one of the most acknowledged mechanisms of epigenetics, is involved in the development of orofacial clefts. DNA methylation has been examined in patients with non-syndromic cleft lip with cleft palate (nsCL/P) from multiple specimens, including blood, saliva, lip, and palate, as well as experimental studies in mice. The results can be reported in two different trends: hypomethylation and hypermethylation. Both hypomethylation and hypermethylation can potentially increase the risk of nsCL/P depending on the types of specimens and the specific regions on each gene and chromosome. This is the most up-to-date review, intending to summarize evidence of the alterations of DNA methylation in association with the occurrence of orofacial clefts. To make things straightforward to understand, we have systematically categorized the data into four main groups: human blood, human tissues, animal models, and the factors associated with DNA methylation. With this review, we are moving closer to the core of DNA methylation associated with nsCL/P development; we hope this is the initial step to find a genetic tool for early detection and prevention of the occurrence of nsCL/P.

Profiling the Influence of Gene Variants Related to Folate-Mediated One-Carbon Metabolism on the Outcome of In Vitro Fertilization (IVF) with Donor Oocytes in Recipients Receiving Folic Acid Fortification

Nutritional status and gene polymorphisms of one-carbon metabolism confer a well-known interaction that in pregnant women may affect embryo viability and the health of the newborn. Folate metabolism directly impacts nucleotide synthesis and methylation, which is of increasing interest in the reproductive medicine field. Studies assessing the genetic influence of folate metabolism on IVF treatments have currently been performed in women using their own oocytes. Most of these patients seeking to have a child or undergoing IVF treatments are advised to preventively intake folate supplies that restore known metabolic imbalances, but the treatments could lead to the promotion of specific enzymes in specific women, depending on their genetic variance. In the present study, we assess the influence of candidate gene variants related to folate metabolism, such as Serine Hydroxymethyltransferase 1 SHMT1 (rs1979276 and rs1979277), Betaine-Homocysteine S-Methyltransferase BHMT (rs3733890), Methionine synthase reductase MTRR (rs1801394), Methylenetetrahydrofolate reductase MTHFR (rs1801131 and rs1801133), methionine synthase MTR (rs12749581), ATP Binding Cassette Subfamily B Member 1 ABCB1 (rs1045642) and folate receptor alpha FOLR1 (rs2071010) on the success of IVF treatment performed in women being recipients of donated oocytes. The implication of such gene variants seems to have no direct impact on pregnancy consecution after IVF; however, several gene variants could influence pregnancy loss events or pregnancy maintenance, as consequence of folic acid fortification.

Association between the Use of Folic Acid Supplements during Pregnancy and Children's Cognitive Function at 7-9 Years of Age in the INMA Cohort Study

This study investigated the association between maternal low (<400 μg/day) or high (≥1000 μg/day) folic acid supplements (FAs) use during pregnancy and the attentional function and working memory in boys and girls at age 7-9. A longitudinal analysis based on 1609 mother-child pairs from the Spanish Infancia y Medio Ambiente Project was carried out. Multivariable regression analyses revealed that, compared to the recommended FAs use, a low FAs use during the second period of pregnancy was associated with a lower alertness in all children (β = 18.70 ms; 95% CI: 7.51; 29.89) and in girls (β = 30.01 ms; 95% CI: 12.96; 47.01), and with a lower N-back Task performance in boys (d' number 2-back (β = -0.25; 95% CI: -0.49; 0.01)). A high FAs use throughout the two periods of pregnancy was associated with a better N-back Task performance only in girls (d' number 2-back (β = 0.28; 95% CI: 0.01; 0.56) and d' number 3-back (β = 0.32; 95% CI: 0.08; 0.56)). The maternal use of FAs beyond the periconceptional period may affect children's attentional function and working memory at age 7-9 differently for boys and girls.

Abnormal transcriptome-wide DNA demethylation induced by folate deficiency causes neural tube defects

Neural tube defect (NTDs) is one of the most common and serious fetal and neonatal birth defects. Neural tube closure (NTC) is an exquisitely coordinated process and this procedure is influenced by both genetic and environmental factor. Folic acid (FA) supplementation is an effective for prevention of a proportion of NTDs, however, the mechanism remains unclear. In this study, our data demonstrated genome-wide enrichment of 5-hydroxymethylcytosine (5hmC) modification on active transcriptional start sites (TSS) and decreased 5-methylcytosine (5mC) binding to TSS under folate deficiency in mESCs (mouse embryonic stem cells). Furthermore, folate deficiency promoted 5hmC enrichment enhancer histone 3 lysine 27 acetylation (H3K27ac) binding to Shh pathway genes in mESCs. Upregulation of Shh target genes was observed in mouse brain tissue under low levels of maternal serum folate, along with increased expression of 5-methylcytosine dioxygenase Tet1 levels. Taken together, we found that folate deficiency promoted DNA demethylation and enriched 5hmC through recruitment of H3K27ac to activate the Shh signaling pathway. These results suggest that the 5hmC modification increases concomitantly with a positive correlation to Shh gene expression in folate deficiency-induced mouse NTDs.

Integrative network analysis revealed the molecular function of folic acid on immunological enhancement in a sheep model

We previously observed the beneficial role of folic acid supplemented from maternal or offspring diet on lamb growth performance and immunity. Twenty-four Hu lambs from four groups (mother received folic acid or not, offspring received folic acid or not) were used in the current study, which was conducted consecutively to elucidate the molecular regulatory mechanisms of folic acid in lambs by analyzing blood metabolome, liver transcriptome, and muscle transcriptome. Serum metabolomics analysis showed that L-homocitrulline, hyodeoxycholic acid, 9-Hpode, palmitaldehyde, N-oleoyl glycine, hexadecanedioic acid, xylose, 1,7-dimethylxanthine, nicotinamide, acetyl-N-formyl-5-methoxykynurenamine, N6-succinyl adenosine, 11-cis-retinol, 18-hydroxycorticosterone, and 2-acetylfuran were down-regulated and methylisobutyrate was up-regulated by the feeding of folic acid from maternal and/or offspring diets. Meanwhile, folic acid increased the abundances of S100A12 and IRF6 but decreased TMEM25 in the liver. In the muscle, RBBP9, CALCR, PPP1R3D, UCP3, FBXL4, CMBL, and MTFR2 were up-regulated, CYP26B1 and MYH9 were down-regulated by the feeding of folic acid. The pathways of bile secretion, biosynthesis of unsaturated fatty acids, linoleic acid metabolism, and herpes simplex virus 1 infection were changed by folic acid in blood, liver, or muscle. Further integrated analysis revealed potential interactions among the liver, blood, and muscle, and the circulating metabolites, hub gene, and pathways, which might be the predominant acting targets of folic acid in animals. These findings provide fundamental information on the beneficial function of folic acid no matter from maternal or offspring, in regulating animal lipid metabolism and immune enhancement, providing a theoretical basis for the use of folic acid from the view of animal health care.

Early Life Stage Folic Acid Deficiency Delays the Neurobehavioral Development and Cognitive Function of Rat Offspring by Hindering De Novo Telomere Synthesis

Early life stage folate status may influence neurodevelopment in offspring. The developmental origin of health and disease highlights the importance of the period of the first 1000 days (from conception to 2 years) of life. This study aimed to evaluate the effect of early life stage folic acid deficiency on de novo telomere synthesis, neurobehavioral development, and the cognitive function of offspring rats. The rats were divided into three diet treatment groups: folate-deficient, folate-normal, and folate-supplemented. They were fed the corresponding diet from 5 weeks of age to the end of the lactation period. After weaning, the offspring rats were still fed with the corresponding diet for up to 100 days. Neurobehavioral tests, folic acid and homocysteine (Hcy) levels, relative telomere length in brain tissue, and uracil incorporation in telomere in offspring were measured at different time points. The results showed that folic acid deficiency decreased the level of folic acid, increased the level of Hcy of brain tissue in offspring, increased the wrong incorporation of uracil into telomeres, and hindered de novo telomere synthesis. However, folic acid supplementation increased the level of folic acid, reduced the level of Hcy of brain tissue in offspring, reduced the wrong incorporation of uracil into telomeres, and protected de novo telomere synthesis of offspring, which was beneficial to the development of early sensory-motor function, spatial learning, and memory in adolescence and adulthood. In conclusion, early life stage folic acid deficiency had long-term inhibiting effects on neurodevelopment and cognitive function in offspring.

Folic Acid Levels During Pregnancy Regulate Trophoblast Invasive Behavior and the Possible Development of Preeclampsia

Background

One of the unique features of placentation is its similarity to tumorigenesis yet being very well regulated. It allows rapid proliferation, migration, and invasion of mononuclear trophoblast cells into the maternal uterus and remodeling the maternal vasculature. This pseudomalignant nature of trophoblastic cells is strictly regulated and its importance becomes evident in abnormal pregnancies that are characterized by aberrant trophoblast proliferation/invasion like preeclampsia. In addition to this, the importance of folic acid supplementation during pregnancy is well documented. We aimed to analyze the molecular and epigenetic regulation of the pseudomalignant nature of placentation via folic acid levels.

Methods

Placental tissue samples were collected from different pregnancies in three different gestational stages. We estimated the impact of folic acid levels on global methylation, LINE1 methylation, and expression of DNMTs in all three gestational stages in pregnant women and preeclampsia pregnancies. We also analyzed the effect of folic acid supplementation on trophoblastic invasion using placental derived cells viz, JEG-3 and HTR-8/SVneo cell line and verified the molecular and epigenetic mechanisms involved in this regulation.

Results

Development of preeclampsia was observed to be associated with lower folate levels in placental tissue, higher global methylation level, and higher expression of DNMT1and DNMT3A. Folic acid supplementation was found to increase the invasive potential of placental trophoblasts by almost two folds which were associated with the decreased expression of tumor suppressor genes and tissue inhibitors of matrix metalloproteinases; and increased expression of oncogenes, telomerase gene, and matrix metalloproteinases. These folic acid-mediated changes were observed to be regulated by CpG methylation in the case of many genes. Folic acid supplementation was also observed to significantly decrease global methylation in placental trophoblasts related to decreasing expression of DNMT1 and DNMT3A.

Conclusion

Lower folic acid levels are associated with preeclampsia development and folic acid supplementation regulates the invasive potential of placental trophoblasts as mediated by various epigenetic changes in the placenta suggesting the protective effect of folic acid against preeclampsia.

Epigenetics of pregnancy: looking beyond the DNA code

Epigenetics is the branch of genetics that studies the different mechanisms that influence gene expression without direct modification of the DNA sequence. An ever-increasing amount of evidence suggests that such regulatory processes may play a pivotal role both in the initiation of pregnancy and in the later processes of embryonic and fetal development, thus determining long-term effects even in adult life. In this narrative review, we summarize the current knowledge on the role of epigenetics in pregnancy, from its most studied and well-known mechanisms to the new frontiers of epigenetic regulation, such as the role of ncRNAs and the effects of the gestational environment on fetal brain development. Epigenetic mechanisms in pregnancy are a dynamic phenomenon that responds both to maternal-fetal and environmental factors, which can influence and modify the embryo-fetal development during the various gestational phases. Therefore, we also recapitulate the effects of the most notable environmental factors that can affect pregnancy and prenatal development, such as maternal nutrition, stress hormones, microbiome, and teratogens, focusing on their ability to cause epigenetic modifications in the gestational environment and ultimately in the fetus. Despite the promising advancements in the knowledge of epigenetics in pregnancy, more experience and data on this topic are still needed. A better understanding of epigenetic regulation in pregnancy could in fact prove valuable towards a better management of both physiological pregnancies and assisted reproduction treatments, other than allowing to better comprehend the origin of multifactorial pathological conditions such as neurodevelopmental disorders.

Impact of In Utero Folate Exposure on DNA Methylation and Its Potential Relevance for Later-Life Health-Evidence from Mouse Models Translated to Human Cohorts

SCOPE

Persistent DNA methylation changes may mediate effects of early-life exposures on later-life health. Human lifespan is challenging for prospective studies, therefore data from longitudinal studies are limited. Projecting data from mouse models of early-life exposure to human studies offers a tool to address this challenge.

METHODS AND RESULTS

C57BL/6J mice were fed low/normal folate diets before and during pregnancy and lactation. Genome-wide promoter methylation was measured in male offspring livers at 17.5 days gestation and 28 weeks. Eight promoters were concurrently hypermethylated by folate depletion in fetuses and adults (>1.10 fold-change; p < 0.05). Processes/pathways potentially influenced by global changes, and function of these eight genes, suggest neurocognitive effects. Human observational and randomized controlled trial data were interrogated for translation. Methylation at birth was inversely associated with maternal plasma folate in six genes (-1.15% to -0.16% per nmol L^-1 ; p < 0.05), while maternal folic acid supplementation was associated with differential methylation of four genes in adulthood. Three CpGs were persistently hypermethylated with lower maternal folate (p = 0.04).

CONCLUSION

Some persistent folate-induced methylation changes in mice are mirrored in humans. This demonstrates utility of mouse data in identifying human loci for interrogation as biomarkers of later-life health.

Correlation among maternal risk factors, gene methylation and disease severity in females with autism spectrum disorder

Aim: To detect early-life environmental factors leading to DNA methylation changes of autism spectrum disorder (ASD)-related genes in young ASD females and reveal epigenetic biomarkers of disease severity. Materials & methods: We investigated blood methylation levels of MECP2, OXTR, BDNF, RELN, BCL2, EN2 and HTR1A genes in 42 ASD females. Results: Maternal gestational weight gain correlated with BDNF methylation levels (Bonferroni-corrected p = 0.034), and lack of folic acid supplementation at periconception resulted in higher disease severity in the ASD children (Bonferroni-corrected p = 0.048). RELN methylation levels were inversely correlated with disease severity (Bonferroni corrected p = 0.042). Conclusion: The present study revealed gene-environment interactions and potential epigenetic biomarkers of disease severity in ASD females.

Managing folate deficiency implies filling the gap between laboratory and clinical assessment

The characterization of folate status in subjects at risk of deficiency and with altered vitamin homeostasis is crucial to endorse preventive intervention health policies, especially in developed countries. Several physiological changes (i.e. pregnancy), clinical situations and diseases have been associated to increased requirement, impaired intake and absorption of folate. However clinical practice guidelines (CPG) endorse folic acid supplementation generally discarding the use of its determination in serum to assess the risk of deficiency and/or its concentration at baseline. Poor confidence on the diagnostic accuracy of serum folate assays still persists in the current CPGs although recent standardization efforts have greatly improved inter-method variability and precision. In this review we critically appraise the methodological issues concerning laboratory folate determination and the evidence on the potential adverse effects of folic acid exposure. The final aim is to build a sound background to promote serum folate-based cost-effective health care policies by optimizing folic acid supplementation in subjects at risk of deficiency and with altered folate homeostasis. Our first result was to adjust in relation to current serum folate assays the thresholds reported by CPGs as index of folate status, defined on the association with metabolic and hematologic indicators. We identify a statistically significant difference between the estimated thresholds and accordingly show that the assessment of folate status actually changes in relation to the assay employed. The use of the method-dependent thresholds here reported may pragmatically endorse the stewardship of folic acid supplementation in clinical practice and increase the cost-effectiveness of health care policies.

Efficacy of 4.0 mg versus 0.4 mg Folic Acid Supplementation on the Reproductive Outcomes: A Randomized Controlled Trial

Folic acid (FA) supplementation prevents neural tube defects (NTDs), but the effects on other reproductive outcomes are unclear. While common recommendation is 0.4 mg/day in addition to regular nutrition, the most appropriate dose of FA is still under debate. We investigated the effects of a higher dose of periconception FA on reducing adverse reproductive outcomes. In this multicenter double-blind randomized controlled trial (RCT), 1060 women (aged 18-44 years and planning a pregnancy) were randomly assigned to receive 4.0 mg or 0.4 mg of FA daily. The primary outcome was the occurrence of congenital malformations (CMs). A composite outcome including one or more adverse pregnancy outcomes was also evaluated. A total of 431 women had a natural conception within 1 year. The primary outcome occurred in 8/227 (3.5%) women receiving 4.0 mg FA and 9/204 (4.4%) women receiving 0.4 mg FA (RR 0.80; 95%CI 0.31 to 2.03). The composite outcome occurred in 43/227 (18.9%) women receiving 4.0 mg FA and 75/204 (36.8%) women receiving 0.4 mg FA (RR 0.51; 95%CI 0.40 to 0.68). FA 4.0 mg supplementation was not associated with different occurrence of CMs, compared to FA 0.4 mg supplementation. However, FA 4.0 mg supplementation was associated with lower occurrence of other adverse pregnancy outcomes.

Maternal folic acid and multivitamin supplementation: International clinical evidence with considerations for the prevention of folate-sensitive birth defects

More evidence is available for maternal intake, absorption, distribution, tissue specific concentrations, and pregnancy outcomes with folic acid (fortification/supplementation) during preconception - first trimester. This Quality Improvement prevention review used expert guidelines/opinions, systematic reviews, randomized control trials/controlled clinical trials, and observational case control/case series studies, published in English, from 1990 to August 2021. Optimization for an oral maternal folic acid supplementation is difficult because it relies on folic acid dose, type of folate supplement, bio-availability of the folate from foods, timing of supplementation initiation, maternal metabolism/genetic factors, and many other factors. There is continued use of high dose pre-food fortification 'RCT evidenced-based' folic acid supplementation for NTD recurrence pregnancy prevention. Innovation requires preconception and pregnancy use of 'carbon one nutrient' supplements (folic acid, vitamin B12, B6, choline), using the appropriate evidence, need to be considered. The consideration and adoption of directed personalized approaches for maternal complex risk could use serum folate testing for supplementation dosing choice. Routine daily folic acid dosing for low-risk women should consider a multivitamin with 0.4 mg of folic acid starting 3 months prior to conception until completion of breastfeeding. Routine folic acid dosing or preconception measurement of maternal serum folate (after 4-6 weeks of folate supplementation) could be considered for maternal complex risk group with genetic/medical/surgical co-morbidities. These new approaches for folic acid oral supplementation are required to optimize benefit (decreasing folate sensitive congenital anomalies; childhood morbidity) and minimizing potential maternal and childhood risk.

Neurodevelopmental effects of maternal folic acid supplementation: a systematic review and meta-analysis

Folic acid, a water-soluble vitamin B nutrient, plays an important role not only in maintaining a healthy pregnancy but also in offspring brain development and function, however, it remains unclear whether maternal folic acid (FA) supplementation associated with the risk of different postnatal neurodevelopmental outcomes. Here, we performed a systematic review and meta-analysis on the impact of maternal FA supplementation on a wide range of postnatal neurodevelopmental outcomes which include intellectual development, risk of autistic traits, ADHD, behavior, language, and psychomotor problems, using studies extracted from the following databases, including MEDLINE, Web of Science, Cochrane Library, Scopus, EMBASE, and PsychInfo. Thirty-two cohort studies and seven case-control studies were included in this meta-analysis. In the present study, we found that prenatal FA supplementation had a positive impact on offspring's neurodevelopmental outcomes, including improved intellectual development and reduced risk of autism traits, ADHD, behavioral, and language problems. We also found that FA over-supplementation was not associated with an improvement in offspring's brain development, and may have a negative impact on offspring's neurodevelopmental outcomes. This study proved the first panoramic review on the relationship of FA supplementation with offspring's neurodevelopment. Further studies focusing on different dosages and periods of FA supplementation are needed.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1993781 .

Association of maternal pre-pregnancy dietary intake with adverse maternal and neonatal outcomes: A systematic review and meta-analysis of prospective studies

This study aimed to summarize the evidence regarding the effects of dietary intake before conception on pregnancy outcomes by performing a systematic review and meta-analysis of prospective studies. Electronic databases were searched from inception up to August 2021. Overall, 65 studies involving 831 798 participants were included and 38 studies were quantitatively pooled. With regard to maternal outcomes, pre-pregnancy intake of fried food, fast food, red and processed meat, heme iron and a low-carbohydrate dietary pattern was positively associated with the risk of gestational diabetes mellitus (GDM) (all P < 0.05). However, a high dietary fiber intake and folic acid supplementation were negatively associated with GDM risk (both P < 0.05). With regard to neonatal outcomes, maternal caffeine intake before pregnancy significantly increased the risk of spontaneous abortion, while folic acid supplementation had protective effects on total adverse neonatal outcomes, preterm birth, and small-for-gestational age (SGA, all P < 0.05). However, no significant associations were found between adverse pregnancy outcomes (i.e., GDM and SGA) and the pre-pregnancy dietary intake of sugar-sweetened beverages, potato, fish, and carbohydrates and the Healthy Eating Index. Our study suggests that maintaining a healthy diet before conception has significant beneficial effects on pregnancy outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1989658.

Choline acts during preimplantation development of the bovine embryo to program postnatal growth and alter muscle DNA methylation

The preimplantation period of embryonic development can be a key window for programming of postnatal development because extensive epigenetic remodeling occurs during this time. It was hypothesized that modification of one-carbon metabolism of the bovine embryo by addition of the methyl-donor choline to culture medium would change postnatal phenotype through epigenetic modification. Embryos produced in vitro were cultured with 1.8 mM choline chloride or control medium. Blastocysts were transferred into females and pregnancy outcomes and postnatal phenotype of the resultant calves determined. Exposure of embryos to choline increased gestation length and calf birth weight. Calves derived from choline-treated embryos were also heavier at weaning and had increased ratio of body weight to hip height than control calves. Choline altered muscle DNA methylation of calves 4 months after birth. A total of 670 of the 8149 CpG examined were differentially methylated, with the predominant effect of choline being hypomethylation. Among the genes associated with differentially methylated CpG were ribosomal RNAs and genes in AMPK, mTOR, integrin, and BEX2 canonical pathways and cellular functions involved in growth and proliferation. Results demonstrate that provision of the methyl-donor choline to the preimplantation embryo can alter its developmental program to increase gestation length, birth weight, and weaning weight and cause postnatal changes in muscle DNA methylation including those associated with genes related to anabolic processes and cellular growth. The importance of the nutritional status of the embryo with respect to one-carbon metabolism for ensuring health and well-being after birth is emphasized by these observations.

Prenatal Stress in Maternal Hyperhomocysteinemia: Impairments in the Fetal Nervous System Development and Placental Function

The article presents current views on maternal hyperhomocysteinemia (HHcy) as an important factor causing prenatal stress and impaired nervous system development in fetuses and newborns in early ontogenesis, as well as complications in adulthood. Experimental data demonstrate that prenatal HHcy (PHHcy) affects the morphological maturation of the brain and activity of its neurotransmitter systems. Cognitive deficit observed in the offspring subjected to PHHcy in experimental studies can presumably cause the predisposition to various neurodegenerative diseases, as the role of maternal HHcy in the pathogenesis such diseases has been proven in clinical studies. The review also discusses molecular mechanisms of the HHcy neurotoxic action on the nervous system development in the prenatal and early postnatal periods, which include oxidative stress, apoptosis activation, changes in the DNA methylation patterns and microRNA levels, altered expression and processing of neurotrophins, and neuroinflammation induced by an increased production of pro-inflammatory cytokines. Special attention is given to the maternal HHcy impact on the placenta function and its possible contribution to the brain function impairments in the offspring. Published data suggest that some effects of PHHcy on the developing fetal brain can be due to the disturbances in the transport functions of the placenta resulting in an insufficient supply of nutrients necessary for the proper formation and functioning of brain structures.

The epigenetic and morphogenetic effects of molecular oxygen and its derived reactive species in development

The development of multicellular organisms involves the unpacking of a complex genetic program. Extensive characterization of discrete developmental steps has revealed the genetic program is controlled by an epigenetic state. Shifting the epigenome is a group of epigenetic enzymes that modify DNA and proteins to regulate cell type specific gene expression. While the role of these modifications in development has been established, the input(s) responsible for electing changes in the epigenetic state remains unknown. Development is also associated with dynamic changes in cellular metabolism, redox, free radical production, and oxygen availability. It has previously been postulated that these changes are causal in development by affecting gene expression. This suggests that oxygen is a morphogenic compound that impacts the removal of epigenetic marks. Likewise, metabolism and reactive oxygen species influence redox signaling through iron and glutathione to limit the availability of key epigenetic cofactors such as α-ketoglutarate, ascorbate, NAD⁺ and S-adenosylmethionine. Given the close relationship between these cofactors and epigenetic marks it seems likely that the two are linked. Here we describe how changing these inputs might affect the epigenetic state during development to drive gene expression. Combined, these cofactors and reactive oxygen species constitute the epigenetic landscape guiding cells along differing developmental paths.

Effects of non-inherited ancestral genotypes on offspring phenotypes

It is well established that environmental exposures can modify the profile of heritable factors in an individual's germ cells, ultimately affecting the inheritance of phenotypes in descendants. Similar to exposures, an ancestor's genotype can also affect the inheritance of phenotypes across generations, sometimes in offspring who do not inherit the genetic aberration. This can occur via a variety of prenatal, in utero, or postnatal mechanisms. In this review, we discuss the evidence for this process in mammals, with a focus on examples that are potentially mediated through the germline, while also considering alternate routes of inheritance. Non-inherited ancestral genotypes may influence descendant's disease risk to a much greater extent than currently appreciated, and focused evaluation of this phenomenon may reveal novel mechanisms of inheritance.

Highly Sensitive Electrochemical Biosensor Using Folic Acid-Modified Reduced Graphene Oxide for the Detection of Cancer Biomarker

The detection of cancer biomarkers in the early stages could prevent cancer-related deaths significantly. Nanomaterials combined with biomolecules are extensively used in drug delivery, imaging, and sensing applications by targeting the overexpressed cancer proteins such as folate receptors (FRs) to control the disease by providing earlier treatments. In this investigation, biocompatible reduced graphene oxide (rGO) nanosheets combined with folic acid (FA)-a vitamin with high bioaffinity to FRs-is utilized to develop an electrochemical sensor for cancer detection. To mimic the cancer cell environment, FR-β protein is used to evaluate the response of the rGO-FA sensor. The formation of the rGO-FA nanocomposite was confirmed through various characterization techniques. A glassy carbon (GC) electrode was then modified with the obtained rGO-FA and analyzed via differential pulse voltammetry (DPV) for its specific detection towards FRs. Using the DPV technique, the rGO-FA-modified electrode exhibited a limit of detection (LOD) of 1.69 pM, determined in a linear concentration range from 6 to 100 pM. This excellent electrochemical performance towards FRs detection could provide a significant contribution towards future cancer diagnosis. Moreover, the rGO-FA sensing platform also showed excellent specificity and reliability when tested against similar interfering biomolecules. This rGO-FA sensor offers a great promise to the future medical industry through its highly sensitive detection towards FRs in a fast, reliable, and economical way.

New gene targets in the study of hypogonadotropic hypogonadism

The incidence of congenital hypogonadotropic hypogonadism (HH) is approximately 1-10 in 100,000 live births. Known syndromes, such as Kallman syndrome, caused by a mutation in the KAL-1 gene, and other genes listed in the Online Mendelian Inheritance in Man database, account for 2/3 of the cases. The rest of these cases where there is no known genetic cause for HH are termed idiopathic. In this editorial, I describe each of the articles in the Special Issue on Hypogonadotropic Hypogonadism, with a focus on new genes that might be included in future screens of idiopathic patients.

Glutathione Protects the Developing Heart from Defects and Global DNA Hypomethylation Induced by Prenatal Alcohol Exposure

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is caused by prenatal alcohol exposure (PAE), the intake of ethanol (C₂ H₅ OH) during pregnancy. Features of FASD cover a range of structural and functional defects including congenital heart defects (CHDs). Folic acid and choline, contributors of methyl groups to one-carbon metabolism (OCM), prevent CHDs in humans. Using our avian model of FASD, we have previously reported that betaine, another methyl donor downstream of choline, prevents CHDs. The CHD preventions are substantial but incomplete. Ethanol causes oxidative stress as well as depleting methyl groups for OCM to support DNA methylation and other epigenetic alterations. To identify more compounds that can safely and effectively prevent CHDs and other effects of PAE, we tested glutathione (GSH), a compound that regulates OCM and is known as a "master antioxidant."

METHODS/RESULTS

Quail embryos injected with a single dose of ethanol at gastrulation exhibited congenital defects including CHDs similar to those identified in FASD individuals. GSH injected simultaneously with ethanol not only prevented CHDs, but also improved survival and prevented other PAE-induced defects. Assays of hearts at 8 days (HH stage 34) of quail development, when the heart normally has developed 4-chambers, showed that this single dose of PAE reduced global DNA methylation. GSH supplementation concurrent with PAE normalized global DNA methylation levels. The same assays performed on quail hearts at 3 days (HH stage 19-20) of development, showed no difference in global DNA methylation between controls, ethanol-treated, GSH alone, and GSH plus ethanol-treated cohorts.

CONCLUSIONS

GSH supplementation shows promise to inhibit effects of PAE by improving survival, reducing the incidence of morphological defects including CHDs, and preventing global hypomethylation of DNA in heart tissues.

Epigenetics of Hepatic Insulin Resistance

Insulin resistance (IR) is largely recognized as a unifying feature that underlies metabolic dysfunction. Both lifestyle and genetic factors contribute to IR. Work from recent years has demonstrated that the epigenome may constitute an interface where different signals may converge to promote IR gene expression programs. Here, we review the current knowledge of the role of epigenetics in hepatic IR, focusing on the roles of DNA methylation and histone post-translational modifications. We discuss the broad epigenetic changes observed in the insulin resistant liver and its associated pathophysiological states and leverage on the wealth of 'omics' studies performed to discuss efforts in pinpointing specific loci that are disrupted by these changes. We envision that future studies, with increased genomic resolution and larger cohorts, will further the identification of biomarkers of early onset hepatic IR and assist the development of targeted interventions. Furthermore, there is growing evidence to suggest that persistent epigenetic marks may be acquired over prolonged exposure to disease or deleterious exposures, highlighting the need for preventative medicine and long-term lifestyle adjustments to avoid irreversible or long-term alterations in gene expression.

Maternal Methyl-Donor Micronutrient Supplementation During Pregnancy Promotes Skeletal Muscle Differentiation and Maturity in Newborn and Weaning Pigs

Adequate maternal methyl-donor micronutrient (MET) intake is an important determinant of the organ development and metabolic renovation of offspring. The mechanism involved in skeletal myogenesis and the effect of MET supplementation during pregnancy on the maternal body remain unclear. Thus, this study aimed to investigate the potential effect of methyl donor micronutrients (MET) on skeletal muscle development and metabolism in offspring using pig models. Forty-three Duroc × Erhualian gilts were assigned to two dietary groups during gestation: control diet (CON) and CON diet supplemented with MET (folic acid, methionine, choline, vitamin B6, and vitamin B12). The results showed that maternal MET exposure during pregnancy significantly increased the concentrations of protein, triiodothyronine (T3), and thyroxine (T4) in colostrum and methyl metabolites, including S-adenosylmethionine (SAM), S-adenosyl-L-homocysteine (SAH), 5-methyl-tetrahydrofolate (5-MTHF), and betaine, in the maternal and offspring umbilical vein serum. A similar pattern was demonstrated in the body weight gain and myofiber diameters in offspring. In addition, maternal MET supplementation significantly increased the concentration of offspring serum insulin-like growth factor 1 (IGF-1), T3, and T4; upregulated the mRNA expression of IGF-1 and IGF-1 receptor (IGF-1r) and the phosphorylation level of protein kinases in offspring longissimus dorsi muscle; and upregulated the expression of myogenic genes and fast myosin heavy chain (fast MyHC) in offspring skeletal muscle. Supplementing sows with higher levels of MET during gestation may promote skeletal muscle differentiation and maturity and improve the skeletal muscle mass of the piglets.

Nutrients, Mitochondrial Function, and Perinatal Health

Mitochondria are active independent organelles that not only meet the cellular energy requirement but also regulate central cellular activities. Mitochondria can play a critical role in physiological adaptations during pregnancy. Differences in mitochondrial function have been found between healthy and complicated pregnancies. Pregnancy signifies increased nutritional requirements to support fetal growth and the metabolism of maternal and fetal tissues. Nutrient availability regulates mitochondrial metabolism, where excessive macronutrient supply could lead to oxidative stress and contribute to mitochondrial dysfunction, while micronutrients are essential elements for optimal mitochondrial processes, as cofactors in energy metabolism and/or as antioxidants. Inadequate macronutrient and micronutrient consumption can result in adverse pregnancy outcomes, possibly through mitochondrial dysfunction, by impairing energy supply, one-carbon metabolism, biosynthetic pathways, and the availability of metabolic co-factors which modulate the epigenetic processes capable of establishing significant short- and long-term effects on infant health. Here, we review the importance of macronutrients and micronutrients on mitochondrial function and its influence on maternal and infant health.