Microglial transcriptome of Maternal Immune Activation model at different developmental Stages and after microglia repopulation
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ABSTRACT: To determine the transcriptomic changes underlying the MIA microglia phenotype and their reversal by PLX, we performed RNA-sequencing of magnetic CD11B beads-isolated microglia from the whole brain in Saline and MIA male and female offspring at E17, P7, P20, and P60, as well as from MG-REP male and female offspring at P60. Microglial transcriptome reveals novel MIA and repopulation modules and overlap of MIA microglial genes with ASD gene network. 14,225 microglial genes from RNA-seq data revealed distinct transcriptional signatures of immature microglia (IM module, 4681 transcripts, enriched in E17 and P7 Saline), MIA immature microglia (MIA-IM module, 2816 transcripts, enriched in E17 and P7 MIA), Juvenile microglia (JM module, 2318 transcripts, enriched in P20 Saline and MIA), Adult microglia (AM module, 3276 transcripts, enriched in P60 Saline + CTRL, P60 MIA + CTRL and P60 MIA + MG-REP), and repopulated adult microglia (REP-AM module, 1,134 transcripts, enriched in P60 Saline + MG-REP)
Project description:We generated single-cell RNAseq profiles of microglia and brain myeloid cells (1922 total; 1816 cells passed quality control) from different developmental stages (E14.5, P7 and P60) to study their heterogeneity. Cells were isolated from either the whole developing brain (for the E14.5 stage) or six separate regions (for P7 and P60 stages): Cortex (CTX), Cerebellum (CB), Hippocampus (HIP), Striatum (STR), Olfactory bulb (OB), Choroid plexus (CP). Single cells were FACS index sorted followed by Smart-seq2 library preparation and Illumina Nextseq (sequence depth > 1 million per cell). All 1816 cells were grouped into 15 clusters using Seurat package (Macosko, Basu, Satija et al. Cell. 2015), and manually annotated based on gene expression signatures and meta data. We found that the majority of adult microglia expressing homeostatic genes are remarkably similar in transcriptomes, regardless of brain region. By contrast, postnatal microglia represent a more heterogeneous population. We discovered a proliferative region-associated microglia (PAM) subset, mainly found in developing white matter, that share a characteristic gene signature with degenerative disease-associated microglia (DAM). Such PAM have amoeboid morphology, are metabolically active, and phagocytose newly formed oligodendrocytes. This scRNA-seq atlas will be a valuable resource for dissecting innate immune functions in health and disease.
Project description:In order to further understand how microglia-derived LAG3 regulates microglia homeostasis and affects the morphogenesis of astrocytes, RNA-seq was used to analyze the transcriptome changes of microglia isolated from Lag3 conditional knockout mice and littermate-born wild-type mice in P7 period. About 7000 transcripts showed the differential expression between the microglia of the corpus callosum of Lag3fl/fl and Lag3cKO-Cx3 mice, with a fold change ≥2, and a p value < 0.05. Geneontology analysis of downregulated genes were enriched in terms related to actin recombination, ciliary recombination and others, while upregulated genes are enriched in inflammatory response and other terms. These results reflected the role of microglia Lag3 in microglia development.
Project description:Dexamethasone (1ug/g, Dex) or vehicle (saline) injected into postnatal days 0-7 (P0 to P7) of C57BL6J mouse pups every day. Whole organ were harvested at P7.
Project description:Efferent inhibition of cochlear outer hair cells is mediated by nicotinic cholinergic receptors containing alpha9 (a9) and alpha10 subunits. Mice lacking a9 nicotinic subunits fail to exhibit classic olivocochlear responses and are characterized by abnormal synaptic morphology at the base of outer hair cells. To detail molecular changes induced upon the loss of a9 subunit, we sampled cochlear RNA from wild type and a9 null mice at postnatal (P) days spanning periods of synapse formation and maturation (P3, P7, P13 and P60). Our findings point to a delay in cochlear maturation starting at the onset of hearing (P13), as well as an up-regulation of various GABA receptor subunits in adult mice lacking the a9 nicotinic subunit. Cochleae were removed at postnatal ages P3, P7, P13 and P60. Cochlear tissues from 3-5 mice were pooled per replicate; biological triplicates were performed for each age and genotype.
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.
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.
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.