Preimplantation or gestation/lactation high-fat diet alters adult offspring metabolism and neurogenesis.

Poor maternal nutrition during pregnancy is known to impair fetal development. Moreover, the preimplantation period is vulnerable to adverse programming of disease. Here, we investigated the effect of a mouse maternal high-fat diet in healthy non-obese dams during preimplantation or throughout pregnancy and lactation on metabolism-related parameters and hippocampal neurogenesis in adult offspring. Female mice were fed from conception either a normal fat diet (normal fat diet group) or high-fat diet throughout gestation and lactation (high-fat diet group), or high-fat diet only during preimplantation (embryonic high-fat diet group, high-fat diet up to E3.5, normal fat diet thereafter). Maternal high-fat diet caused changes in the offspring, including increased systolic blood pressure, diurnal activity, respiratory quotient, and energy expenditure in high-fat diet females, and increased systolic blood pressure and respiratory quotient but decreased energy expenditure in high-fat diet males. High-fat diet males had a higher density of newborn neurons and a lower density of mature neurons in the dentate gyrus, indicating that exposure to a maternal high-fat diet may regulate adult neurogenesis. A maternal high-fat diet also increased the density of astrocytes and microglia in the hippocampus of high-fat diet males and females. Generally, a graded response (normal fat diet < embryonic high-fat < high-fat diet) was observed, with only 3 days of high-fat diet exposure altering offspring energy metabolism and hippocampal cell density. Thus, early maternal exposure to a fatty diet, well before neural differentiation begins and independently of maternal obesity, is sufficient to perturb offspring energy metabolism and brain physiology with lifetime consequences.

Epigenetics in the Uterine Environment: How Maternal Diet and ART May Influence the Epigenome in the Offspring with Long-Term Health Consequences.

The societal burden of non-communicable disease is closely linked with environmental exposures and lifestyle behaviours, including the adherence to a poor maternal diet from the earliest preimplantation period of the life course onwards. Epigenetic variations caused by a compromised maternal nutritional status can affect embryonic development. This review summarises the main epigenetic modifications in mammals, especially DNA methylation, histone modifications, and ncRNA. These epigenetic changes can compromise the health of the offspring later in life. We discuss different types of nutritional stressors in human and animal models, such as maternal undernutrition, seasonal diets, low-protein diet, high-fat diet, and synthetic folic acid supplement use, and how these nutritional exposures epigenetically affect target genes and their outcomes. In addition, we review the concept of thrifty genes during the preimplantation period, and some examples that relate to epigenetic change and diet. Finally, we discuss different examples of maternal diets, their effect on outcomes, and their relationship with assisted reproductive technology (ART), including their implications on epigenetic modifications.

FOXD1 mutations are related to repeated implantation failure, intra-uterine growth restriction and preeclampsia.

BACKGROUND: Human reproductive disorders consist of frequently occurring dysfunctions including a broad range of phenotypes affecting fertility and women's health during pregnancy. Several female-related diseases have been associated with hypofertility/infertility phenotypes, such as recurrent pregnancy loss (RPL). Other occurring diseases may be life-threatening for the mother and foetus, such as preeclampsia (PE) and intra-uterine growth restriction (IUGR). FOXD1 was defined as a major molecule involved in embryo implantation in mice and humans by regulating endometrial/placental genes. FOXD1 mutations in human species have been functionally linked to RPL's origin. METHODS: FOXD1 gene mutation screening, in 158 patients affected by PE, IUGR, RPL and repeated implantation failure (RIF), by direct sequencing and bioinformatics analysis. Plasmid constructs including FOXD1 mutations were used to perform in vitro gene reporter assays. RESULTS: Nine non-synonymous sequence variants were identified. Functional experiments revealed that p.His267Tyr and p.Arg57del led to disturbances of promoter transcriptional activity (C3 and PlGF genes). The FOXD1 p.Ala356Gly and p.Ile364Met deleterious mutations (previously found in RPL patients) have been identified in the present work in women suffering PE and IUGR. CONCLUSIONS: Our results argue in favour of FOXD1 mutations' central role in RPL, RIF, IUGR and PE pathogenesis via C3 and PlGF regulation and they describe, for the first time, a functional link between FOXD1 and implantation/placental diseases. FOXD1 could therefore be used in clinical environments as a molecular biomarker for these diseases in the near future.

Study of five novel non-synonymous polymorphisms in human brain-expressed genes in a Colombian sample.

BACKGROUND: Non-synonymous single nucleotide polymorphisms (nsSNPs) in brain-expressed genes represent interesting candidates for genetic research in neuropsychiatric disorders. PURPOSE: To study novel nsSNPs in brain-expressed genes in a sample of Colombian subjects. METHODS: We applied an approach based on in silico mining of available genomic data to identify and select novel nsSNPs in brain-expressed genes. We developed novel genotyping assays, based in allele-specific PCR methods, for these nsSNPs and genotyped them in 171 Colombian subjects. RESULTS: Five common nsSNPs (rs6855837; p.Leu395Ile, rs2305160; p.Thr394Ala, rs10503929; p.Met289Thr, rs2270641; p.Thr4Pro and rs3822659; p.Ser735Ala) were studied, located in the CLOCK, NPAS2, NRG1, SLC18A1 and WWC1 genes. We reported allele and genotype frequencies in a sample of South American healthy subjects. There is previous experimental evidence, arising from genome-wide expression and association studies, for the involvement of these genes in several neuropsychiatric disorders and endophenotypes, such as schizophrenia, mood disorders or memory performance. CONCLUSIONS: Frequencies for these nsSNPSs in the Colombian samples varied in comparison to different HapMap populations. Future study of these nsSNPs in brain-expressed genes, a synaptogenomics approach, will be important for a better understanding of neuropsychiatric diseases and endophenotypes in different populations.

A novel cost-effective assay based on real-time PCR for COMT Val158Met genotyping.

A functional polymorphism in the catechol-O-methyltransferase (COMT) gene (Val158Met) has been associated with a large number of human diseases and endophenotypes. The aim of this study was to develop a novel cost-effective assay to genotype this polymorphism. The novel assay was based on the combination of allele-specific PCR and high-resolution melting in a qPCR platform. Melt-curve analysis allowed a clear differentiation of the three genotypes. This novel assay could be implemented in the study of a large number of diseases and endophenotypes related to COMT dysfunction and could be extended for the analysis of other functional polymorphisms.

Common functional polymorphisms in SLC6A4 and COMT genes are associated with circadian phenotypes in a South American sample.

The molecular study of circadian rhythms in humans could be an excellent approach to understand the relation between genes and behavior. It is possible that variations in genes involved in neurotransmission and/or synaptic plasticity, such as catechol-O-methyltransferase (COMT) and serotonin transporter (SLC6A4) could be of particular interest in understanding human circadian phenotypes. The aim of this study is to analyze the possible and novel associations of the functional polymorphisms in COMT and SLC6A4 genes (Val158Met and 5-HTTLPR) and circadian phenotypes in healthy Colombian subjects. 191 university students were genotyped for two functional polymorphisms in COMT and SLC6A4 genes (rs4680 and rs4795541). We applied two scales to measure phenotypic patterns of human circadian rhythms: Composite Scale of Morningness (CSM) and Epworth Sleepiness Scale (ESS). We found a significant association between 5-HTTLPR polymorphism and morning preference score (CSM) (p = 0.027) using an overdominant genotypic model and association of COMT Val158Met with daytime sleepiness (ESS scores) (p = 0.038) in a genotypic recessive model. These results were supported by differences in genotype frequencies between circadian typologies for SLC6A4 gene (p = 0.007) and categories of diurnal sleepiness for COMT gene (p = 0.032). Our results suggest, for the first time, a significant relationship between functional SLC6A4 and COMT polymorphisms with specific human circadian phenotypes: morning preference and diurnal sleepiness. These results need to be replicated in other populations. Further study of functional polymorphisms in other synaptic genes could be of relevance for the identification of novel candidate genes for circadian phenotypes, and related endophenotypes of neuropsychiatric importance, in healthy humans.

A functional polymorphism in the promoter region of MAOA gene is associated with daytime sleepiness in healthy subjects.

Excessive daytime sleepiness (EDS) is one of the main causes of car and industrial accidents and it is associated with increased morbidity and alterations in quality of life. Prevalence of EDS in the general population around the world ranges from 6.2 to 32.4%, with a heritability of 38-40%. However, few studies have explored the role of candidate genes in EDS. Monoamine oxidase A (MAOA) gene has an important role in the regulation of neurotransmitter levels and a large number of human behaviors. We hypothesized that a functional VNTR in the promoter region of the MAOA gene might be associated with daytime sleepiness in healthy individuals. The Epworth sleepiness scale (ESS) was applied to 210 Colombian healthy subjects (university students), which were genotyped for MAOA-uVNTR. MAOA-uVNTR showed a significant association with ESS scores (p = 0.01): 3/3 genotype carriers had the lowest scores. These results were supported by differences in MAOA-uVNTR frequencies between diurnal somnolence categories (p = 0.03). Our finding provides evidence for the first time that MAOA-uVNTR has a significant association with EDS in healthy subjects. Finally, these data suggest that functional variations in MAOA gene could have a role in other phenotypes of neuropsychiatric relevance.

A novel association of two non-synonymous polymorphisms in PER2 and PER3 genes with specific diurnal preference subscales.

The circadian system is responsible for the generation and maintenance of physiological and behavioral rhythms in mammals and allows synchronization with the environment. Different polymorphisms in clock genes have been studied in healthy humans, providing inconsistent results in different populations. In this study, we evaluated the possibility that two non-synonymous polymorphisms in PER2 (p.Gly1244Glu, rs934945) and PER3 (p.Met1028Thr, rs2640909) genes might be associated with diurnal preference in healthy Colombian subjects. A total of 209 Colombian university students were genotyped for two functional polymorphisms in PER2 and PER3 genes (rs934945 and rs2640909). We applied the composite scale of morningness (CSM) to measure phenotypic patterns of human diurnal preference. Additionally, we extracted from the CSM three subscale scores ("morningness", "activity planning" and "morning alertness"). We used a false discovery rate approach (q values) for correction of multiple testing. PER2 (rs934945) showed a significant association with two CSM subscale scores: "activity planning" and "morning alertness". For PER3 (rs2640909), we observed an association with the "morningness" CSM subscale scores. We found a significant association between novel and functional polymorphisms in PER2 and PER3 genes with specific CSM subscales for diurnal preference. We showed for the first time the association of rs934945 with "morning alertness" and rs2640909 with "morningness". We suggest that these results should be replicated in order to confirm the association in other populations. Finally, the study of additional novel functional polymorphisms in other clock genes could be of relevance for a deep understanding of circadian phenotypes and neuropsychiatric disorders.