Project description:Maternal over- and undernutrition in pregnancy plays a critical role in fetal brain development and function. The effects of different maternal diet compositions on intrauterine programming of the fetal brain in the absence of maternal obesity or maternal undernutrition is a lesser-explored area. The goal of this study was to investigate the impact of two different maternal diets on fetal brain gene expression signatures, fetal/neonatal growth, and neonatal behavior in a mouse model. Female C57Bl/6J mice were fed one of two commercially-available chow diets (pelleted vs. powdered) with differing micronutrient and carbohydrate compositions throughout pregnancy and lactation. The powdered chow diet was richer in carbohydrates and lower in micronutrients than the pelleted chow diet, among other differences. On embryonic day 15.5, embryos were weighed and measured. Fetal brains were snap frozen. RNA was extracted from fetal forebrains for five fetuses per diet group and hybridized to whole genome expression microarrays. Functional analyses identified significant upregulation of canonical pathways and upstream regulators involved in cell cycle regulation, synaptic plasticity, and sensory nervous system development in the fetal brain, and significant downregulation of pathways related to cell and embryo death. Pathways related to DNA damage response, humoral and cell-mediated immune response, carbohydrate and lipid metabolism, small molecule biosynthesis, and amino acid metabolism were also dysregulated. Maternal dietary content is an important variable for researchers evaluating fetal brain development and offspring behavior to consider. Selection of a chow diet matched for micronutrients is crucial to avoid unexpected or undesired effects on offspring brain development and behavior.
Project description:Numerous studies have established a link between maternal diet and the physiological and metabolic phenotypes of the offspring. In previous studies in sheep, we demonstrated that different maternal diets had altered the transcriptome of fetal tissues. However, the mechanisms underlying those transcriptomic changes are poorly understood. DNA methylation is an epigenetic mark regulating transcription and is largely influenced by dietary components of the one-carbon cycle, a generator of the methyl group donor. Therefore, in the present study, we hypothesized that different maternal diets during pregnancy will alter the DNA methylation and gene expression patterns in fetal tissues. Pregnant ewes were randomly divided into two groups each of which received a hay or corn diet from mid-gestation (day 67±5) until necropsy (day 131 ± 1). The diets were formulated to meet the nutritional needs of ewes during pregnancy. On the day of necropsy, longissimus dorsi (LD) muscle tissues were collected from the fetuses and then used for DNA methylation analysis and gene expression profiling.
Project description:Increasing trends of obesity in childbearing women with a concurrent gestational diabetes are often associated with adverse fetal metabolic cues. Not only the carbohydrates but also fats are considered to contribute additional dietary fuels to the fetal hearts. To examine the hitherto unknown epigenetic mechanisms on the offspring’s cardiometabolic health due to maternal high-fat (HF) diet (40% kcal) or streptozotocin (STZ)-induced diabetic pregnancy, or both, we carried out an epigenetic characterization of neonatal heart tissue using chromatin immunoprecipitation (ChIP) sequening and a previously validated rat model. Chromatin landscape of offspring’s heart tissue revealed differential peaks distribution on various promoter regions mapped to the rat genome due to histone (H3) modifications by acetylation (H3Ac) or trimethylations of lysine 4 and 27 (H3K4me3 and H3K27me3, respectively). Ongoing evaluations include gene ontology and disease ontology analyses. Together, it is expected that the findings will show that maternal HF-diet with or without gestational diabetes changes the cardiac histone signature in rat offspring, potentially leading to development of novel disease prevention strategies.
Project description:Objective Recent evidence indicates that the adult hematopoietic system is susceptible to diet-induced lineage skewing. It is not known whether the developing hematopoietic system is subject to metabolic programming via in utero high fat diet (HFD) exposure, an established mechanism of adult disease in several organ systems. We previously reported substantial losses in offspring liver size with prenatal HFD. As the liver is the main hematopoietic organ in the fetus, we asked whether the developmental expansion of the hematopoietic stem and progenitor cell (HSPC) pool is compromised by prenatal HFD and/or maternal obesity. Methods We used quantitative assays, progenitor colony formation, flow cytometry, transplantation, and gene expression assays with a series of dietary manipulations to test the effects of gestational high fat diet and maternal obesity on the day 14.5 fetal liver hematopoietic system. Results Maternal obesity, particularly when paired with gestational HFD, restricts physiological expansion of fetal HSPCs while promoting the opposing cell fate of differentiation. Importantly, these effects are only partially ameliorated by gestational dietary adjustments for obese dams. Competitive transplantation reveals compromised repopulation and myeloid-biased differentiation of HFD-programmed HSPCs to be a niche-dependent defect, apparent in HFD-conditioned male recipients. Fetal HSPC deficiencies coincide with perturbations in genes regulating metabolism, immune and inflammatory processes, and stress response, along with downregulation of genes critical for hematopoietic stem cell self-renewal and activation of pathways regulating cell migration. Conclusions Our data reveal a previously unrecognized susceptibility to nutritional and metabolic developmental programming in the fetal HSPC compartment, which is a partially reversible and microenvironment-dependent defect perturbing stem and progenitor cell expansion and hematopoietic lineage commitment. Examination of differentially expressed genes between gestational day 15 (+/- 0.5 days) C57BL/6 mouse fetal livers from diet-induced (60% fat diet) obese or control female mice.
Project description:Both the fetus and the mother who are involved in maternal anti-fetal rejection during pregnancy show distinct alterations in the peripheral blood transcriptome Total RNA isolated from umbilical cord blood and maternal blood was compared between cases without (Normal) and with maternal anti-fetal rejection (FIRS2) using whole genome DASL assay.
Project description:“Dysbiosis" of the maternal gut microbiome, in response to environmental challenges such as infection, altered diet and stress during pregnancy, has been increasingly associated with abnormalities in offspring brain function and behavior. However, whether the maternal gut microbiome regulates neurodevelopment in the absence of environmental challenge remains unclear. In addition, whether the maternal microbiome exerts such influences during critical periods of embryonic brain development is poorly understood. Here we investigate how depletion, and selective reconstitution, of the maternal gut microbiome influences fetal neurodevelopment in mice. Embryos from antibiotic-treated and germ-free dams exhibit widespread transcriptomic alterations in the fetal brain relative to conventionally-colonized controls, with reduced expression of several genes involved in axonogenesis. In addition, embryos from microbiome-depleted mothers exhibit deficient thalamocortical axons and impaired thalamic axon outgrowth in response to cell-extrinsic guidance cues and growth factors. Consistent with the importance of fetal thalamocortical axonogenesis for shaping neural circuits for sensory processing, restricted depletion of the maternal microbiome from pre-conception through mid-gestation yields offspring that exhibit tactile hyposensitivity in select sensorimotor behavioral tasks. Gnotobiotic colonization of antibiotic-treated dams with a limited consortium of spore-forming bacteria indigenous to the gut microbiome prevents abnormalities in fetal brain gene expression, fetal thalamocortical axonogenesis and adult tactile sensory behavior associated with maternal microbiome depletion. Metabolomic profiling reveals that the maternal microbiota regulates levels of numerous small molecules in the maternal serum as well as the brains of fetal offspring. Select microbiota-dependent metabolites – trimethylamine N-oxide, 5-aminovalerate, imidazole propionate, and hippurate – sufficiently promote axon outgrowth from fetal thalamic explants. Moreover, maternal supplementation with the metabolites during early gestation abrogates deficiencies in fetal thalamocortical axons and prevents abnormalities in tactile sensory behavior in offspring from microbiome-depleted dams. Altogether, these findings reveal that the maternal gut microbiome promotes fetal thalamocortical axonogenesis and select tactile sensory behaviors in mice, likely by signaling of microbially modulated metabolites to neurons in the developing brain.
Project description:Maternal immune activation is associated with adverse offspring neurodevelopmental outcomes, many mediated by in utero microglial programming. As microglia remain inaccessible throughout development, identification of noninvasive biomarkers reflecting fetal brain microglial programming could permit screening and intervention. We used lineage tracing to demonstrate the shared ontogeny between fetal brain macrophages (microglia) and fetal placental macrophages (Hofbauer cells) in a mouse model of maternal diet-induced obesity, and single-cell RNA-seq to demonstrate shared transcriptional programs. Comparison with human datasets demonstrated conservation of placental resident macrophage signatures between mice and humans. Single-cell RNA-seq identified common alterations in fetal microglial and Hofbauer cell gene expression induced by maternal obesity, as well as sex differences in these alterations. We propose that Hofbauer cells, which are easily accessible at birth, provide novel insights into fetal brain microglial programs, and may facilitate the early identification of offspring vulnerable to neurodevelopmental disorders in the setting of maternal exposures.
Project description:Activation of the maternal immune system during pregnancy can fetal development, which can lead to postnatal susceptibility to a wide range of diseases, including cardiovascular, metabolic and psychiatric disorders. During maternal immune activation (MIA), the maternal body must balance its ressources between mounting an immune response and investing resources into continued metabolism and growth : both essential for survival of the fetus and a successful pregnancy. How the placenta responds to MIA over time and how it can protect the fetus is not well understood, and neither are the fetal consequences of MIA. Here, we characterised the response to an induced acute inflammation in maternal lungs over time across maternal and fetal organs, using a combination of omics-methods, imaging and integrative computational analysis. We found that the placenta, unlike other maternal organs, did not react by inducing a typical inflammatory response, but instead initially induced genes associated to strengthen tissue integrity and simultaneously reduced growth to prevent exposure to potential infections. Afterwards, a return to homeostasis was observed, with heightened biosynthesis and expression of endoplasmic reticulum (ER) stress genes. This mechanism likely protects the fetus from inflammation, as we observed no immune response in the fetal liver transcriptome. Instead, we observed metabolic adaptations in the fetus, including a release of docosahexaenoic acid (DHA) Notably, DHA has a crucial function for fetal brain development , and levels of triglyceride and phosphatidylcholine lipids that are necessary for transportation of DHA to the brain were also increased. This metabolic response is likely a combination of the placental MIA response and temporary maternal fasting, caused by MIA-induced fever and lack of nutrient intake. Our study shows, for the first time, the temporal and systemic response to MIA in lungs across maternal and fetal organs.
Project description:Maternal immune cells (called 'Maternal microchimeric cells' (short: MMc)) seed fetal brain tissue during pregnancy. We used single cell RNA sequencing (scRNA-seq) to characterize the diversity of MMc in the fetal brain.
Project description:Both the fetus and the mother who are involved in maternal anti-fetal rejection during pregnancy show distinct alterations in the peripheral blood transcriptome