Fetal brain response to maternal inflammation requires microglia [Developing_Microglia]
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ABSTRACT: In utero infection and maternal inflammation can adversely impact fetal brain development. Maternal systemic illness, even in the absence of direct fetal central nervous system infection, is associated with an increased risk of autism and schizophrenia in affected offspring. The cell types mediating the response of the fetal brain to maternal inflammation are largely unknown, hindering the development of therapies to prevent and treat adverse neuropsychiatric outcomes. Here, we show that microglia are enriched for expression of receptors for relevant pathogens and cytokines throughout embryonic development.
Project description:In utero infection and maternal inflammation can adversely impact fetal brain development. Maternal systemic illness, even in the absence of direct fetal central nervous system infection, is associated with an increased risk of autism and schizophrenia in affected offspring. The cell types mediating the response of the fetal brain to maternal inflammation are largely unknown, hindering the development of therapies to prevent and treat adverse neuropsychiatric outcomes. Here, we show that microglia are enriched for expression of receptors for relevant pathogens and cytokines throughout embryonic development.
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 dietary protein deficiency and nematode infection during early pregnancy have negative impacts on both maternal placental gene expression and fetal growth in the mouse. Here we used next-generation RNA sequencing to test our hypothesis that maternal protein deficiency and/or nematode infection also alter the expression of genes in the developing fetal brain. Outbred pregnant CD1 mice were used in a 2x2 design with two levels of dietary protein (24% and 6%) and two levels of infection (repeated sham and Heligmosomoides bakeri beginning at gestation day 5). Pregnant dams were euthanized on gestation day 18 to harvest the whole fetal brain. Four fetal brains from each treatment group were analyzed using RNA Hi-seq sequencing and the differential expression of genes was determined by edgeR package using NetworkAnalyst. In response to maternal H. bakeri infection, 96 genes (88 up-regulated and 8 down-regulated) were differentially expressed in the fetal brain. Differentially expressed genes were involved in metabolic processes, developmental processes and immune system according to the PANTHER classification system. Among the important biological functions identified, several upregulated genes have known neurological functions including neurodevelopment (Gdf15, Ing4), neural differentiation (miRNA let-7), synaptic plasticity (via suppression of NF-κβ), neuro-inflammation (S100A8, S100A9) and glucose metabolism (Tnnt1, Atf3). However, in response to maternal protein deficiency, brain specific serine protease (Prss22) was the only upregulated gene and only one gene (Dynlt1a dynein light chain) responded to the interaction of maternal nematode infection and PD. In conclusion, maternal exposure to GI nematode infection from day 5 to 18 of pregnancy may influence developmental programming of the fetal brain.
Project description:Maternal immune activation is a risk factor for the development of schizophrenia and autism. Infections during pregnancy activate the mother's immune system and alter the fetal environment with sub-sequence effects of CNS function and behavior in the offspring, but the cellular and molecular links between infection-induced altered fetal development and risk for neuropsychiatric disorders are unknown. We investigated the immunological, molecular, and behavioral effects of MIA in the offspring of pregnant Sprague-Dawley rats given an intraperitoneal (0.25 mg/kg) injection of lipopolysaccharide (LPS) on embryonic day 15. LPS significantly elevated pro-inflammatory cytokines in maternal serum, amniotic fluid, and fetal brain at 4 h, and levels decreased but remained elevated at 24 h. Offspring born to LPS-dams exhibited reduced social and exploration behaviors as juveniles and young adults. Whole genome microarray analysis of the fetal brain at 4 h post maternal LPS was performed to elucidate possible molecular mechanisms by which MIA effects the fetal brain. We observed dysregulation of 3,285 genes in restricted functional categories, with increased mRNA expression of cellular stress and cell death genes and reduced expression of developmentally-regulated and brain-specific genes, specifically those that regulate neuronal migration of GABAergic interneurons. 19 Fetal Rat Brain Samples: 10 (-) LPS, 9 (+) LPS.
Project description:To investigate the effects of maternal adiposity and leptin on fetal brain development, fetal hippocampal brain tissue was collected at 0.9 term for bulk RNA Seq analysis
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.