Rare heterozygous coding variants in the triggering receptor expressed in myeloid cells 2 (TREM2) gene, conferring increased risk of developing late-onset Alzheimer''s disease, have been identified. We examined the transcriptional consequences of the loss of Trem2 in mouse brain to better understand its role in disease using differential expression and coexpression network analysis of Trem2 knockout and wild-type mice. We generated RNA-Seq data from cortex and hippocampus sampled at 4 and 8 months. Using brain cell-type markers and ontology enrichment, we found subnetworks with cell type and/or functional identity. We primarily discovered changes in an endothelial gene-enriched subnetwork at 4 months, including a shift toward a more central role for the amyloid precursor protein gene, coupled with widespread disruption of other cell-type subnetworks, including a subnetwork with neuronal identity. We reveal an unexpected potential role of Trem2 in the homeostasis of endothelial cells that goes beyond its known functions as a microglial receptor and signaling hub, suggesting an underlying link between immune response and vascular disease in dementia. Methods: We performed differential expression and co-expression network analysis on a RNA-Seq profiled Trem2 knockout (KO) mouse using two brain areas sampled at 4- and 8-months to obtain a systems level view of the effects of the absence of Trem2. Results: The absence of Trem2 has a stronger effect at an earlier age with the number of differential expressed (DE) genes being 17-fold greater at 4 months than at 8 months in cortex. By integrating DE genes and network analysis, we discovered gene clusters associated with the disruption of blood vessel formation at 4 months of age and protein targeting primarily affecting the hippocampus at 8 months. Further integration of cell type and ontology information revealed a large disruption of a gene module enriched for endothelial cell markers coinciding with the module enriched for neuron cell markers having weaker connections to modules with oligodendrocyte and astrocyte identities. The module with neuronal identity has decreased expression only in the KO where it has closer association with a new module enriched for phagocytic functions. Conclusions: Combining gene co-expression and differential expression analysis on a newly generated RNA-Seq profiled Trem2 KO mouse demonstrate that the absence of Trem2 produces a disruption which mainly affects endothelialon related processes at 4 months of age. It results in a ripple effect that disrupts the cross-talk of other cell types at 8 months, including reduced expression of a gene module enriched in neuron related functions and a shift towards a more central role for App. This study reveals an unexpected role of Trem2 in the homeostasis of endothelial cells that goes beyond its known functions as a microglial receptor and signaling hub suggesting new paths for investigation at the intersection between Trem2, Alzheimer's disease and vascular dementia. Overall design: Hippocampus and cortex were selected because they represent tissues affected in AD at early and late stages, respectively (Matarin 2015, Mastrangelo 2008). Brain tissue samples were obtained from male Trem2 knockout (KO) and wild type (WT) control mice at two time points: 4 months and 8 months. These time points span the onset and late disease stages in well established AD mouse models (Matarin 2015). RNA-Seq was used to profile the transcriptomes for each sample. Two technical replicates were obtained for each sample.
Loss of Trem2 in microglia leads to widespread disruption of cell coexpression networks in mouse brain.
Sex, Specimen part, Subject
View SamplesWe profiled global gene expression for two separate lines of mouse embryonic fibroblasts and find that deletion of PKM2 and expression of PKM1 does not alter global gene expression profiles.
Pyruvate kinase isoform expression alters nucleotide synthesis to impact cell proliferation.
No sample metadata fields
View SamplesTumors engender an environment dominated by M2 differentiated tumor macrophages that support tumor invasion, metastases and escape from immune control. In this study, we demonstrate that following radiation therapy of tumors in mice there is an influx of tumor macrophages that polarize towards wound repair and immune suppression.
Expression of NF-κB p50 in tumor stroma limits the control of tumors by radiation therapy.
Specimen part, Treatment, Time
View SamplesTo gain insight into the molecular underpinnings of the post-mating response that depend on the germline, we independently assess the contribution of the female germline and the male germline on gene expression changes in head tissues of females using RNA-seq. Overall design: mRNA profiles of head tissues in virgin and mated (1 and 3 days post-mating) females that either have or are lacking a germline and females mated to males that either have or are lacking a germline. Samples were generated in triplicate and sequenced on an Illumina Genome Analyzer IIx.
The <i>Drosophila</i> Post-mating Response: Gene Expression and Behavioral Changes Reveal Perdurance and Variation in Cross-Tissue Interactions.
Sex, Age, Subject
View SamplesBlood-stage malaria initiates both innate and adaptive immune responses, inclusive a strong activation of the mononuclear phagocyte network. Here we show that Plasmodium infection results in a transient loss of embryonically established tissue-resident macrophages in spleen, liver and lungs, much before the peak of parasitemia. During acute blood-stage malaria, fate mapping analysis revealed that inflammatory monocytes contribute to the repopulation of the emptied niches of splenic red pulp macrophages and hepatic Kupffer cells, while lung alveolar macrophages refill their niche mainly through self-renewal. Interestingly, the local microenvironment of spleen and liver can “imprint” the molecular characteristics of fetal-derived macrophages in new immigrants from bone marrow including almost identical gene expression profiles and turnover kinetics. Overall design: Mice were infected with parasitized P. yoelii erythrocytes. Organ samples were collected in triplicates from uninfected mice and from mice infected 35 days before and after parasite clearance.
Organ-Specific Fate, Recruitment, and Refilling Dynamics of Tissue-Resident Macrophages during Blood-Stage Malaria.
Specimen part, Subject
View SamplesWe used gene expression microarrays to identify genes whose expression was influenced differently by TNFa in Fancc-deficient mice compared to wild type (WT) mice. To identify genes whose expression was directly or indirectly influenced by Fancc, we looked in particular for genes either suppressed or induced by TNF in WT cells that were not affected by TNF in Fancc-deficient cells.
FANCL ubiquitinates β-catenin and enhances its nuclear function.
Specimen part
View SamplesThe inflammatory gene response requires activation of the protein kinase TAK1, but it is currently unknown how TAK1-derived signals coordinate transcriptional programs in the genome. We determined the genome-wide binding of the TAK1-controlled NF-?B subunit p65 in relation to active enhancers and promoters of transcribed genes by ChIP-seq experiments. Out of 35,000 active enhancer regions, 410 H3K4me1-positive enhancers show interleukin (IL)-1-induced H3K27ac and p65 binding. Inhibition of TAK1, IKK2 or depletion of p65 blocked inducible enhancer activation and gene expression. As exemplified by the CXC chemokine cluster located on chromosome 4, the TAK1-p65 pathway also regulates the recruitment kinetics of the histone acetyltransferase CBP, of NF-?B p50 and of AP-1 transcription factors to both, promoters and enhancers. This study provides a high resolution view of epigenetic changes occurring during the IL-1 response and allows the first genome-wide identification of a novel class of inducible p65 NF-?B-dependent enhancers in epithelial cells. Overall design: RNA-seq of KB cells either untreated or treated with IL-1 alpha
The Activation of IL-1-Induced Enhancers Depends on TAK1 Kinase Activity and NF-κB p65.
No sample metadata fields
View SamplesFollowing exposure to vaccines, antigen-specific CD8+ T-cell responses develop as long-term memory pools. Novel vaccine strategies based on adenoviral vectors, e.g. those developed for HCV, are able to induce and sustain substantial CD8+ T-cell populations. How such populations evolve following vaccination remains to be defined at a transcriptional level. We addressed the transcriptional regulation of divergent CD8+ T-cell memory pools induced by an adenoviral vector encoding a model antigen (beta-galactosidase). We observe transcriptional profiles that mimic those following infection with persistent pathogens, murine and human cytomegalovirus (CMV). Key transcriptional hallmarks include up-regulation of homing receptors, and anti-apoptotic pathways, driven by conserved networks of transcription factors, including T-bet (TBX21). In humans, a novel adenovirus vaccine induced similar CMV-like phenotypes and underlying transcription factor regulation. These data clarify the core features of CD8+ T-cell memory following vaccination with adenovirus vectors and indicate a conserved pathway for memory development shared with persistent herpesviruses.
Adenoviral Vector Vaccination Induces a Conserved Program of CD8(+) T Cell Memory Differentiation in Mouse and Man.
Specimen part
View SamplesInduced pluripotent stem cell (iPSC)-derived cortical neurons present a powerful new model of neurological disease. Previous work has established that differentiation protocols produce cortical neurons but little has been done to characterise these at cellular resolution. In particular, it is unclear to what extent in vitro two-dimensional, relatively disordered culture conditions recapitulate the development of in vivo cortical layer identity. Single cell multiplex RT-qPCR was used to interrogate the expression of genes previously implicated in cortical layer or phenotypic identity in individual cells. Unexpectedly, 22.7% of neurons analysed frequently co-expressed canonical fetal deep and upper cortical layer markers, and this co-expression was also present at the level of translated protein. By comparing our results to available single cell RNA-seq data from human fetal and adult brain, we observed that this co-expression of layer markers was also seen in primary tissue. These results suggest that establishing neuronal layer identity in iPSC-derived or primary cortical neurons using canonical marker genes transcripts is unlikely to be informative. Overall design: Single cell RNA-seq of 16 iPSC-derived cortical neurons. This dataset was used for normalization purposes for GSE67835.
Assessing similarity to primary tissue and cortical layer identity in induced pluripotent stem cell-derived cortical neurons through single-cell transcriptomics.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of cDC1- and cDC2-committed DC progenitors reveals early lineage priming at the common DC progenitor stage in the bone marrow.
Sex
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