Project description:Prenatal stress is one of the risk factors for the development of mental disorders in offspring, but its underlying mechanism remains elusive. To perform epigenomic profiling of prenatal stress effects on fetal brains, ATAC-seq and RNA-seq were used to explore the changes of chromatin accessibility and gene expression on embryonic brains at E15.5 of offspring from pregnant mice, which were exposed to chronic mild unpredictable stress between E5.5 to E14.5.
Project description:Organoids derived from human pluripotent stem cells recapitulate the early three-dimensional organization of human brain, but whether they establish the epigenomic and transcriptional programs essential for brain development is unknown. We compared epigenomic and gene regulatory features in cerebral organoids and human fetal brain, using genome-wide, base resolution DNA methylome and transcriptome sequencing. Transcriptomic dynamics in organoids faithfully modeled gene expression trajectories in early-to-mid human fetal brains. We found that early non-CG methylation accumulation at super-enhancers in both fetal brain and organoids marks forthcoming transcriptional repression in the fully developed brain. 74% of 35,627 demethylated regions identified during organoid differentiation overlapped with fetal brain regulatory elements. Interestingly, pericentromeric repeats showed widespread demethylation in multiple types of in vitro human neural differentiation models but not in fetal brain. Our study reveals that organoids recapitulate many epigenomic features of mid-fetal human brain and also identified novel non-CG methylation signatures of brain development.
Project description:Maternal exposure to stress during pregnancy is associated with an increased risk of psychiatric disorders in the offspring in later life. The mechanisms through which the effects of maternal stress are transmitted to the fetus are unclear, however the placenta, as the interface between mother and fetus, is likely to play a key role. Using a rat model, we investigated a role for placental oxidative stress in conveying the effects of maternal social stress to the fetus and the potential for treatment using a nanoparticle-bound antioxidant to prevent adverse outcomes in the offspring. Maternal psychosocial stress increased circulating corticosterone in the mother, but not in the fetuses. Maternal stress also induced oxidative stress in the placenta, but not in the fetal brain. Blocking oxidative stress using an antioxidant prevented the prenatal stress-induced anxiety phenotype in the male offspring, and prevented sex-specific neurobiological changes, specifically a reduction in dendrite lengths in the hippocampus, as well as reductions in the number of parvalbumin-positive neurons and GABA receptor subunits in the hippocampus and basolateral amygdala of the male offspring. Importantly, many of these effects were mimicked in neuronal cultures by application of placental-conditioned medium or fetal plasma from stressed pregnancies, indicating molecules released from the placenta may mediate the effects of prenatal stress on the fetal brain. Indeed, both placenta-conditioned medium and fetal plasma contained differentially abundant microRNAs following maternal stress, and their predicted targets were enriched for genes relevant to nervous system development and psychiatric disorders. The results highlight placental oxidative stress as a key mediator in transmitting the maternal social stress effects on the offspring's brain and behaviour, and offer a potential intervention to prevent stress-induced fetal programming of affective disorders.
Project description:Prenatal adversity or stress can have long-term consequences on developmental trajec-tories and health outcomes. Although the biological mechanisms underlying these effects are poorly understood, epigenetic modifications, such as DNA methylation, have the potential to link early-life environments to alterations in physiological systems, with long-term functional impli-cations. We investigated the consequences of two prenatal insults, prenatal alcohol exposure (PAE) and food-related stress, on DNA methylation profiles of the rat brain during early devel-opment. As these insults can have sex-specific effects on biological outcomes, we analyzed epige-nome-wide DNA methylation patterns in prefrontal cortex, a key brain region involved in cogni-tion, executive function, and behavior, of both males and females. We found sex-dependent and sex-concordant influences of these insults on epigenetic patterns. These alterations occurred in genes and pathways related to brain development and immune function, suggesting that PAE and food-related stress may reprogram neurobiological/physiological systems partly through central epigenetic changes, and may do so in a sex-dependent manner. Such epigenetic changes may re-flect the sex-specific effects of prenatal insults on long-term functional and health outcomes and may have important implications for understanding possible mechanisms underlying fetal alco-hol spectrum disorder and other neurodevelopmental disorders.
Project description:Prenatal maternal stress (PNMS) determines lifetime mental and physical health. Here, we show in rats that PNMS has consequences for placental function and fetal brain development across four generations (F0-F3). Using a systems biology approach, comprehensive DNA methylation (DNAm), miRNA, and mRNA profiling revealed a moderate impact of PNMS in the F1 generation, but drastic changes in F2 and F3 generations, suggesting compounding effects of PNMS with each successive generation. Both maternal and placental miRNA gene targets included de novo DNA methyltransferases, indicating robust PNMS-induced disruption in the complex epigenetic regulatory network between miRNAs and DNAm. Transgenerational programming mainly involved genes and biological pathways associated with neurological and psychiatric diseases which were linked to maternal-fetal crosstalk facilitated by the placenta. The highly correlated placenta-brain profiles support the use of placenta as a noninvasive biomarker resource to predict pathological changes in the neonatal brain. The transgenerational persistence of critical DNAm, miRNA and mRNA signatures may explain familial non-genetic disease risks.
Project description:Prenatal maternal stress (PNMS) determines lifetime mental and physical health. Here, we show in rats that PNMS has consequences for placental function and fetal brain development across four generations (F0-F3). Using a systems biology approach, comprehensive DNA methylation (DNAm), miRNA, and mRNA profiling revealed a moderate impact of PNMS in the F1 generation, but drastic changes in F2 and F3 generations, suggesting compounding effects of PNMS with each successive generation. Both maternal and placental miRNA gene targets included de novo DNA methyltransferases, indicating robust PNMS-induced disruption in the complex epigenetic regulatory network between miRNAs and DNAm. Transgenerational programming mainly involved genes and biological pathways associated with neurological and psychiatric diseases which were linked to maternal-fetal crosstalk facilitated by the placenta. The highly correlated placenta-brain profiles support the use of placenta as a noninvasive biomarker resource to predict pathological changes in the neonatal brain. The transgenerational persistence of critical DNAm, miRNA and mRNA signatures may explain familial non-genetic disease risks.
Project description:Epigenetic dysregulation is a universal feature of cancer that results in altered patterns of gene expression that drive malignancy. Brain tumors exhibit subtype-specific epigenetic alterations, however the molecular mechanisms responsible for these diverse epigenetic states remain unclear. Here we show that the developmental transcription factor Sox9 differentially regulates epigenomic states in high-grade glioma (HGG) and ependymoma (EPN). These contrasting roles for Sox9 correspond with protein interactions with histone deacetylating complexes in HGG, and association with the Rela oncofusion in EPN. Together, our studies demonstrate how epigenomic states are differentially regulated in distinct subtypes of brain tumors, while revealing divergent roles for Sox9 in HGG and EPN tumorigenesis.
Project description:Intergenerational stress increases lifetime susceptibility to depression and other psychiatric disorders. Whether intergenerational stress transmission is a consequence of in-utero neurodevelopmental disruptions or early-life mother-infant interaction is largely unknown, due to the complexity, superposition, and inseparability between the prenatal and postnatal mechanisms. Here we show that prenatal stress, through exposing pregnant mice to predator scent, induces depressive-like behavior and social deficits. Cross-fostering experiments indicate divergent and convergent mechanisms of both in utero and early-life parenting environments and support a two-hit model of stress transmission. According to this model, prenatal stress (first-hit) primes brain metabolome and transcriptome (metabotranscriptome), and increases vulnerability to the second-hit in early life, triggered by poor caregiving by the traumatized mothers. Metabolomics, transcriptomic and bioinformatics analyses reveal mechanisms that involve stress- and hypoxia- response metabolic pathways in the brains of the newborn mice, likely through the production of the epigenetic modifiers 2-Hydroxyglutaric acid and succinic acid. These responses produce long-lasting alterations in mitochondrial-energy metabolism, and epigenetic processes pertaining to DNA and chromatin modifications. We demonstrate that an early pharmacological intervention – correction of the mitochondria metabolism, and epigenetic modifications with acetyl-L-carnitine (ALCAR) supplementation - produces long-lasting protection against the behavioral deficits associated with intergenerational transmission of traumatic stress.
Project description:DNA methylation profiling of CD34 positive cells derived from cord blood at birth following prenatal stress The groups consist of 8 individuals with low levels of prenatal stress (control) and 10 individuals with high levels of prenatal stress (stress)