Project description:The mechanisms controlling genome methylation during human embryogenesis remain largely unknown. Here we provide evidence that maternal age at pregnancy permanently alters the epigenetic profile of offspring. We measured DNA methylation in blood at over 450,000 CpGs across the epigenome in 890 newborns.
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.
Project description:Rates of oxytocin use to induce or augment labor are increasing in the United States with little understanding of the impact on offspring development. Using a prairie vole animal model, we have shown that oxytocin administered to mothers can reach offspring brains with long lasting impacts on the development of social behaviors. Here, we examine the epigenetic and transcriptomic consequences of oxytocin exposure during birth in juvenile male offspring. First, we show that male offspring exposed to oxytocin at birth have increased epigenetic age compared to the saline exposed group. We also find 900 differentially methylated CpG sites (annotated to 589 genes), with 2 CpG sites (2 genes) remaining significant after correction for multiple comparisons. Differentially methylated CpG sites are involved in regulation of gene expression and neurodevelopment. Using RNA-sequencing we find 217 nominally differentially expressed genes (p<0.05) in nucleus accumbens, a brain region involved in reward circuitry and social behavior, including 6 genes that remain significantly differentially expressed after corrections for multiple comparisons. Finally, we show that maternal oxytocin administration leads to widespread alternative splicing in the nucleus accumbens. These results indicate that oxytocin exposure during birth has long lasting epigenetic consequences in the brain and warrant further investigation of how oxytocin administration impacts development and behavior throughout the lifespan.
Project description:Rates of oxytocin use to induce or augment labor are increasing in the United States with little understanding of the impact on offspring development. Using a prairie vole animal model, we have shown that oxytocin administered to mothers can reach offspring brains with long lasting impacts on the development of social behaviors. Here, we examine the epigenetic and transcriptomic consequences of oxytocin exposure during birth in juvenile male offspring. First, we show that male offspring exposed to oxytocin at birth have increased epigenetic age compared to the saline exposed group. We also find 900 differentially methylated CpG sites (annotated to 589 genes), with 2 CpG sites (2 genes) remaining significant after correction for multiple comparisons. Differentially methylated CpG sites are involved in regulation of gene expression and neurodevelopment. Using RNA-sequencing we find 217 nominally differentially expressed genes (p<0.05) in nucleus accumbens, a brain region involved in reward circuitry and social behavior, including 6 genes that remain significantly differentially expressed after corrections for multiple comparisons. Finally, we show that maternal oxytocin administration leads to widespread alternative splicing in the nucleus accumbens. These results indicate that oxytocin exposure during birth has long lasting epigenetic consequences in the brain and warrant further investigation of how oxytocin administration impacts development and behavior throughout the lifespan.
Project description:It is known that both maternal and paternal health/disease can influence the early development and later metabolic homeostasis of the offspring. We investigated whether maternal exercise during gestation alone could protect the offspring from the adverse effects of either maternal or paternal obesity induced by high-fat diet (HFD). To understand the underlying mechanisms we performed transcriptomics, whole-genome DNA methylation and targeted DNA methylation analysis at the metabolic master regulator, peroxisome proliferator-activated receptor g coactivator-1a (Pgc-1a) promoter in the adult offspring skeletal muscle. Both maternal and paternal HFD resulted in impaired glucose tolerance in the offspring at 9 months of age. Maternal exercise during gestation completely mitigated this metabolic impairment induced by either maternal or paternal HFD. Adult offspring exposed to either maternal or paternal HFD without exercise during gestation had skeletal muscle transcriptional profiles enriched in genes regulating inflammation and immune responses, whereas maternal exercise resulted in a transcriptional profile that was more similar to control offspring from normal chow fed parents. Changes in promoter and CpG DNA methylation were detected between the groups but did not explain the transcriptional changes. Maternal HFD increased methylation of the Pgc-1α promoter at CpG -260, which was prevented by maternal exercise. Paternal HFD did not affect the methylation of the Pgc-1α promoter. These findings demonstrate the negative consequences of maternal and paternal obesity for the offspring’s metabolic outcomes later in life and the clear benefits of maternal exercise during gestation. The mechanisms involve transcriptional regulation of skeletal muscle likely through multiple types of epigenetic modifications.
Project description:It is known that both maternal and paternal health/disease can influence the early development and later metabolic homeostasis of the offspring. We investigated whether maternal exercise during gestation alone could protect the offspring from the adverse effects of either maternal or paternal obesity induced by high-fat diet (HFD). To understand the underlying mechanisms we performed transcriptomics, whole-genome DNA methylation and targeted DNA methylation analysis at the metabolic master regulator, peroxisome proliferator-activated receptor g coactivator-1a (Pgc-1a) promoter in the adult offspring skeletal muscle. Both maternal and paternal HFD resulted in impaired glucose tolerance in the offspring at 9 months of age. Maternal exercise during gestation completely mitigated this metabolic impairment induced by either maternal or paternal HFD. Adult offspring exposed to either maternal or paternal HFD without exercise during gestation had skeletal muscle transcriptional profiles enriched in genes regulating inflammation and immune responses, whereas maternal exercise resulted in a transcriptional profile that was more similar to control offspring from normal chow fed parents. Changes in promoter and CpG DNA methylation were detected between the groups but did not explain the transcriptional changes. Maternal HFD increased methylation of the Pgc-1α promoter at CpG -260, which was prevented by maternal exercise. Paternal HFD did not affect the methylation of the Pgc-1α promoter. These findings demonstrate the negative consequences of maternal and paternal obesity for the offspring’s metabolic outcomes later in life and the clear benefits of maternal exercise during gestation. The mechanisms involve transcriptional regulation of skeletal muscle likely through multiple types of epigenetic modifications.
Project description:As the evolution of miRNA genes has been found to be one of the important factors in formation of the modern type of man, we performed a comparative analysis of the evolution of miRNA genes in two archaic hominines, Homo sapiens neanderthalensis and Homo sapiens denisova, and elucidated the expression of their target mRNAs in bain.A comparative analysis of the genomes of primates, including species in the genus Homo, identified a group of miRNA genes having fixed substitutions with important implications for the evolution of Homo sapiens neanderthalensis and Homo sapiens denisova. The mRNAs targeted by miRNAs with mutations specific for Homo sapiens denisova exhibited enhanced expression during postnatal brain development in modern humans. By contrast, the expression of mRNAs targeted by miRNAs bearing variations specific for Homo sapiens neanderthalensis was shown to be enhanced in prenatal brain development.Our results highlight the importance of changes in miRNA gene sequences in the course of Homo sapiens denisova and Homo sapiens neanderthalensis evolution. The genetic alterations of miRNAs regulating the spatiotemporal expression of multiple genes in the prenatal and postnatal brain may contribute to the progressive evolution of brain function, which is consistent with the observations of fine technical and typological properties of tools and decorative items reported from archaeological Denisovan sites. The data also suggest that differential spatial-temporal regulation of gene products promoted by the subspecies-specific mutations in the miRNA genes might have occurred in the brains of Homo sapiens denisova and Homo sapiens neanderthalensis, potentially contributing to the cultural differences between these two archaic hominines.