Project description:The maternal microbiota plays an important role in shaping and priming infant immunity, although the cellular and molecular mechanisms underlying these effects remain obscure. Here we report that prenatal antibiotic exposure caused significant elevation of group 2 innate lymphoid cells (ILC2s) in neonatal lungs, in both cell numbers and functionality. Downregulation of type 1 interferon signaling in ILC2s caused by diminished production of microbiota-derived metabolite butyrate represents the underlying mechanism. Mice lacking butyrate receptor GPR41 (GPR41-/-) or type 1 interferon receptor (Ifnar1-/-) recapitulated the phenotype of neonatal ILC2s upon maternal antibiotic exposure. Furthermore, prenatal antibiotic exposure induced persistent epigenetic changes in ILC2s and had a long-lasting deteriorative effect on allergic airway inflammation in adulthood. Prenatal supplementation with butyrate ameliorated airway inflammation in adult offspring born to antibiotic-exposed dams. These observations demonstrate an essential role for the maternal microbiota in the control of type 2 innate immunity at the neonatal stage, which provides a therapeutic window for treating asthma in early life.
Project description:Neutrophilic airway inflammation is highly prevalent in racehorses in training, with the term mild to moderate equine asthma (MMEA) being applied to the majority of such cases. The current study is largely derived from the strong association between MMEA in racehorses and their entry into a race training program; this has led to our primary aim of measuring the effect of race training on pulmonary immune cell function. The objectives of this study are to characterise the effect of training on the local pulmonary immune system and quantify the magnitude of effect by defining the gene expression of tracheal wash (TW) derived cells from Thoroughbred racehorses prior to (T0) and following commencement of race training (T1). This study demonstrated TW samples to represent a rich source of airway cells and RNA to study airway immunity in the horse and highlighted the benefits of advanced-omic methodological approach to studying the dynamics of equine airway immunity. Intense training induced quantifiable alterations in both gene expression of airway derived cells consistent with deregulation of airway immunity and haemopoietic abnormalities. Respectively, these findings likely reflect the known associations between race training and both airway inflammation and bleeding, in particular offering further insight into the potential mechanisms which underpin training associated airway inflammation.
Project description:We examined how prenatal inflammation shapes tissue function and immunity in the lung by reprogramming tissue-resident immune cells from early development. Maternal, but not fetal, type I interferon-mediated inflammation provoked expansion and hyperactivation of group 2 innate lymphoid cells (ILC2s) seeding the developing lung. Hyperactivated ILC2s produced increased IL-5 and IL-13, were associated with acute Th2 bias, decreased Tregs, and persistent lung eosinophilia into adulthood. ILC2 hyperactivation was recapitulated by adoptive transfer of a fetal liver precursor following prenatal inflammation, indicative of developmental programming at the fetal progenitor level. Reprogrammed ILC2 hyperactivation and subsequent lung immune remodeling, including persistent eosinophilia, was associated with worsened histopathology and increased airway dysfunction equivalent to papain exposure, indicating increased asthma susceptibility in offspring. Our data elucidate a potential mechanism by which early-life inflammation results in increased asthma susceptibility, driven by hyperactivated ILC2s that drive persistent changes to lung immunity during perinatal development.
Project description:Background The timing and mechanisms of asthma inception remain imprecisely defined. Although epigenetic mechanisms likely contribute to asthma pathogenesis, little is known about their role in asthma inception. Objective To assess whether the trajectory to asthma begins already at birth and epigenetic mechanisms, specifically DNA methylation, contribute to asthma inception. Methods We used a combination of methyl binding protein-dependent DNA capture and microarrays to survey DNA methylation in cord blood mononuclear cells (CBMC) from 36 children (18 non-asthmatic, 18 asthmatic by age 9) from the Infant Immune Study (IIS), an unselected birth cohort closely monitored for asthma for a decade. SMAD3 methylation in IIS (n=60) and in two replication cohorts (The Manchester Asthma and Allergy Study, n=30, and the Childhood Origins of ASThma Study, n=28) was analyzed by bisulfite sequencing or Illumina 450K arrays. CBMC-derived IL-1b was measured by ELISA. Results Neonatal immune cells harbored 589 differentially methylated regions (DMRs) that distinguished IIS children who did and did not develop asthma by age 9. In all three cohorts, methylation in SMAD3, the most connected hub within the network of asthma-associated DMRs, was selectively increased in asthmatic children of asthmatic mothers and was associated with childhood asthma risk. Moreover, SMAD3 methylation in IIS neonates with maternal asthma was strongly and positively associated with neonatal production of IL-1b, an innate inflammatory mediator. Conclusions The trajectory to childhood asthma begins at birth and involves epigenetic modifications in immunoregulatory and pro-inflammatory pathways. Maternal asthma influences epigenetic mechanisms that contribute to the inception of this trajectory.
Project description:RATIONALE: In a mouse model of maternal transmission of asthma risk (J. Immunol 170:1683, 2003), baby mice of asthmatic (As), but not normal (Nrm), mothers show increased susceptibility to allergy. We previously showed that adoptive transfer to normal baby mice of dendritic cells (DCs) harvested from asthma-susceptible but allergen-naïve neonates reproduces the increased susceptibility to asthma. Hence, the maternal effect is mediated by altered neonatal DCs, which skew immune responses towards a pro-allergic Th2 phenotype. To identify potential molecular mechanisms, we performed epigenomic profiling of isolated neonatal DCs. METHODS: BALB/c mice were sensitized by 2 i.p. injections of ovalbumin (OVA) in alum and repeatedly challenged with OVA aerosols (As) prior to mating with normal males. Purified splenic CD11c+ DCs of 14-day old allergen-naïve offspring from these As and control Nrm mothers were isolated using magnetic beads. Methylation profiles of genomic DNA were obtained using Switchgear epigenomic chip arrays. After normalization and background correction analysis using significance analysis for microarrays (SAM) and ANOVA was performed. RESULTS: We identified 300 to 6000 (depending on stringency) chromosomal regions with significantly different methylation status, (2 â 10 fold). Clustering methods and pathway analysis identified several interrelated gene groups that merit further study. CONCLUSION: Maternal asthma causes multiple significant epigenetic changes in neonatal dendritic cells. Keywords: Dendritic cells, genomic DNA, DNA methylation, allergy, asthma The analysis includes 9 samples of genomic DNA from isolated splenic CD11c+ dendritic cells (>95% pure) per group. The two groups are neonates born to mothers with induced allergy to ovalbumin, and normal control neonates. All neonates are genetically and environmentally identical, and allergen-naive.
Project description:RATIONALE: In a mouse model of maternal transmission of asthma risk (J. Immunol 170:1683, 2003), baby mice of asthmatic (As), but not normal (Nrm), mothers show increased susceptibility to allergy. We previously showed that adoptive transfer to normal baby mice of dendritic cells (DCs) harvested from asthma-susceptible but allergen-naïve neonates reproduces the increased susceptibility to asthma. Hence, the maternal effect is mediated by altered neonatal DCs, which skew immune responses towards a pro-allergic Th2 phenotype. To identify potential molecular mechanisms, we performed epigenomic profiling of isolated neonatal DCs. METHODS: BALB/c mice were sensitized by 2 i.p. injections of ovalbumin (OVA) in alum and repeatedly challenged with OVA aerosols (As) prior to mating with normal males. Purified splenic CD11c+ DCs of 14-day old allergen-naïve offspring from these As and control Nrm mothers were isolated using magnetic beads. Methylation profiles of genomic DNA were obtained using Switchgear epigenomic chip arrays. After normalization and background correction analysis using significance analysis for microarrays (SAM) and ANOVA was performed. RESULTS: We identified 300 to 6000 (depending on stringency) chromosomal regions with significantly different methylation status, (2 – 10 fold). Clustering methods and pathway analysis identified several interrelated gene groups that merit further study. CONCLUSION: Maternal asthma causes multiple significant epigenetic changes in neonatal dendritic cells. Keywords: Dendritic cells, genomic DNA, DNA methylation, allergy, asthma
Project description:Introduction: Prenatal and postnatal cigarette smoke exposure enhances the risk of developing asthma. Despite this as well as other smoking related risks, 11% of women still smoke during pregnancy. We hypothesized that cigarette smoke exposure during prenatal development generates long lasting differential methylation altering transcriptional activity that correlates with disease. Methods: In a house dust mite (HDM) model of allergic airway disease, we measured airway hyperresponsiveness (AHR) and airway inflammation between mice exposed prenatally to cigarette smoke (CS) or filtered air (FA). DNA methylation and gene expression were then measured in lung tissue. Results: We demonstrate that HDM-treated CS mice develop a more severe allergic airway disease compared to HDM-treated FA mice including increased AHR and airway inflammation. While DNA methylation changes between the two HDM-treated groups failed to reach genome-wide significance, 99 DMRs had an uncorrected p-value < 0.001. 6 of these 99 DMRs were selected for validation, based on the immune function of adjacent genes, and only 2 of the 6 DMRs confirmed the bisulfite sequencing data. Additionally, genes near these 6 DMRs (Lif, Il27ra, Tle4, Ptk7, Nfatc2, and Runx3) are differentially expressed between HDM-treated CS mice and HDM-treated FA mice. Conclusions: Our findings confirm that prenatal exposure to cigarette smoke is sufficient to modify allergic airway disease, however, it is unlikely that specific methylation changes account for the exposure-response relationship. These findings highlight the important role in utero cigarette smoke exposure plays in the development of allergic airway disease. Lung DNA methylation profiles of mice exposed in utero to cigarette smoke (CS) then treated with house dust mite (HDM, n = 8) or saline (n = 6), or exposed in utero to filtered air (FA) then treated with HDM (n = 9) or saline (n = 6)
Project description:Mild to moderate equine asthma is prevalent in young racehorses, particularly early in their training period. Although the precise aetiopathogenesis remains undetermined, it is possible that the susceptibility of this population might partly reflect an exercise-associated immune derangement at the level of the airway. We performed a genome-wide basal gene expression scan on alveolar macrophages (AMs) isolated from Standardbred racehorses prior to and after commencement of competition race training with a view to identifying any exercise-associated gene expression modulation consistent with functional alterations which might reflect training-associated immunological derangement.
Project description:Recent studies suggested that microglia, the primary brain immune cells, can affect circuit connectivity and neuronal function. Microglia infiltrate the neuroepithelium early in embryonic development and are maintained in the brain throughout adulthood. Several maternal environmental factors, such as aberrant microbiome, immune activation, and poor nutrition, can influence prenatal brain development. Nevertheless, it is unknown how changes in the prenatal environment instruct the developmental trajectory of infiltrating microglia, which in turn affect brain development and function. Here we show that after maternal immune activation (MIA) microglia from the offspring have a long-lived decrease in immune reactivity (blunting) across the developmental trajectory. The blunted immune response was concomitant with changes in the chromatin accessibility and reduced transcription factor occupancy of the open chromatin. Single cell RNA sequencing revealed that MIA does not induce a distinct subpopulation but rather decreases the contribution to inflammatory microglia states. Prenatal replacement of MIA microglia with physiological infiltration of naïve microglia ameliorated the immune blunting and restored a decrease in presynaptic vesicle release probability onto dopamine receptor type-two medium spiny neurons, indicating that aberrantly formed microglia due to an adverse prenatal environment impacts the long-term microglia reactivity and proper striatal circuit development.
Project description:Recent studies suggested that microglia, the primary brain immune cells, can affect circuit connectivity and neuronal function. Microglia infiltrate the neuroepithelium early in embryonic development and are maintained in the brain throughout adulthood. Several maternal environmental factors, such as aberrant microbiome, immune activation, and poor nutrition, can influence prenatal brain development. Nevertheless, it is unknown how changes in the prenatal environment instruct the developmental trajectory of infiltrating microglia, which in turn affect brain development and function. Here we show that after maternal immune activation (MIA) microglia from the offspring have a long-lived decrease in immune reactivity (blunting) across the developmental trajectory. The blunted immune response was concomitant with changes in the chromatin accessibility and reduced transcription factor occupancy of the open chromatin. Single-cell RNA sequencing revealed that MIA does not induce a distinct subpopulation but rather decreases the contribution to inflammatory microglia states. Prenatal replacement of MIA microglia with physiological infiltration of naïve microglia ameliorated the immune blunting and restored a decrease in presynaptic vesicle release probability onto dopamine receptor type-two medium spiny neurons, indicating that aberrantly formed microglia due to an adverse prenatal environment impacts the long-term microglia reactivity and proper striatal circuit development.