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 SamplesPurpose: We isolated Drosophila midgut cells : Delta+ intestinal stem cells (ISCs), Su(H)+enteroblasts (EBs), Esg+ cells (ISC+EB), Myo1A+Enterocytes (ECs), Pros+Enteroendocrine cells (EEs) and How+Visceral muscle cells (VM) from whole midguts to identify stem cell specific genes and study cell type specificities of midgut cells. We also isolated all the cell types from the 5 major regions (R1-R5) of the Drosophila midgut to study differences in cells in different regions. Methods: 3-7 day old female flies were dissected. Flies with GFP/YFP marking different cell types (using the GAL4-UAS system) were used to separate cells of the midgut.The midguts were dissociated with Elastase and FACS sorted using FACS AriaIII. RNA was extracted, amplified and sequenced. Whole midgut samples were sequenced on Illumina GAIIX and regional cell populations were sequenced on HiSeq2000. Methods:Raw fastqc reads were mapped to the Drosophila genome (Drosophila_melanogaster.BDGP5.70.dna.toplevel.fa) using Tophat 2.0.9 at default (using boost_1_54_0, bowtie2-2.1.0, samtools-0.1.19). Methods: For differential expression analysis, DESeq (p-value adjustment 0.05 by method Benjamini-Hochberg) was used. The reads were normalized also to Reads per kilobase of transcript per million mapped reads (RPKM). Results: More than 50% of the genome is expressed in the adult midgut (FlyAtlas- Chintapalli et al., 2007), of these genes about 50% (2457) were differentially expressed (DE) between all 4 cell types (ISCs, EBs, ECs and EEs) atleast 2 folds with 95% confidence Results: 159 genes that were specifically enriched in ISCs, 509 genes were specifically repressed in ISCs Conclusions: Our study represents the first detailed analysis of Drosophila intestinal cell transcriptomes, with biologic replicates, generated by RNA-seq technology.Our data facilitates comparative investigations of expression profiles of cells and reveals novel stem cell genes. Further region specific profiling adds precision to the analysis of variances in the midgut regions. We identify transcriptional regulators and regional transcription factors which modulate the midgut physiology. The dataset will be a great resource for hypothesis generation, tool building and fine tuned studies on the Drosophila midgut. Overall design: mRNA profiles of Drosophila intestinal cells from whole midguts and midgut regions were generated by Deep Sequencing. Whole midgut profiles were generated in triplicates (Illumina GAIIx, 72 bp read length) and regional cell type profiles were genrated in duplicates (HiSeq 2000, 50bp read length).
Regional Cell-Specific Transcriptome Mapping Reveals Regulatory Complexity in the Adult Drosophila Midgut.
Sex, Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Retinoic acid-induced pancreatic stellate cell quiescence reduces paracrine Wnt-β-catenin signaling to slow tumor progression.
No sample metadata fields
View SamplesWe evaluated the change in expression of genes after treatment of stellate cells with retinoic acid to understand how the stellate cells can de-differentiate and effect their physiological behaviour in pathological conditions. We then tested the changes in the gene expression in 2D and 3D culture conditions for pancreatic stellate cells and in a pancreatic cancer model.
Retinoic acid-induced pancreatic stellate cell quiescence reduces paracrine Wnt-β-catenin signaling to slow tumor progression.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Genomic occupancy of Runx2 with global expression profiling identifies a novel dimension to control of osteoblastogenesis.
Specimen part
View SamplesWe evaluated the change in expression of genes after treatment of stellate cells with retinoic acid to understand how the stellate cells can de-differentiate and effect their physiological behaviour in pathological conditions. We then tested the changes in the gene expression in 2D and 3D culture conditions for pancreatic stellate cells and in a pancreatic cancer model.
Retinoic acid-induced pancreatic stellate cell quiescence reduces paracrine Wnt-β-catenin signaling to slow tumor progression.
No sample metadata fields
View SamplesOsteogenesis is a highly regulated developmental process and continues during the turnover and repair of mature bone. Runx2, the master regulator of osteoblastogenesis, directs a transcription program essential for bone formation through both genetic and epigenetic mechanisms. While individual Runx2 gene targets have been identified, further insights into the broad spectrum of Runx2 functions required for osteogenesis are needed. By performing genome-wide characterization of Runx2 binding at the three major stages of osteoblast differentiation: proliferation, matrix deposition and mineralization, we identified Runx2-dependent regulatory networks driving bone formation. Using chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-Seq) over the course of these stages, we discovered close to 80,000 significantly enriched regions of Runx2 binding throughout the mouse genome. These binding events exhibited distinct patterns during osteogenesis, and were associated with proximal promoters as well as a large percentage of Runx2 occupancy in non-promoter regions: upstream, introns, exons, transcription termination site (TTS) regions, and intergenic regions. These peaks were partitioned into clusters that are associated with genes in complex biological processes that support bone formation. Using Affymetrix expression profiling of differentiating osteoblasts depleted of Runx2, we identified novel Runx2 targets including Ezh2, a critical epigenetic regulator; Crabp2, a retinoic acid signaling component; Adamts4 and Tnfrsf19, two remodelers of extracellular matrix. We demonstrated by luciferase assays that these novel biological targets are regulated by Runx2 occupancy at non-promoter regions. Our data establish that Runx2 interactions with chromatin across the genome reveal novel genes, pathways and transcriptional mechanisms that contribute to the regulation of osteoblastogenesis.
Genomic occupancy of Runx2 with global expression profiling identifies a novel dimension to control of osteoblastogenesis.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identifying Nuclear Matrix-Attached DNA Across the Genome.
Specimen part, Cell line
View SamplesExperimental approaches to define the relationship between gene expression and nuclear matrix attachment regions (MARs) have given contrasting and method-specific results. We have developed a next generation sequencing strategy to identify MARs across the human genome (MAR-Seq). The method is based on crosslinking chromatin to its nuclear matrix attachment sites to minimize changes during biochemical processing. We used this method to compare nuclear matrix organization in MCF-10A mammary epithelial-like cells and MDA-MB-231 breast cancer cells and evaluated the results in the context of global gene expression (array analysis) and positional enrichment of gene-regulatory histone modifications (ChIP-Seq). In the normal-like cells, nuclear matrixattached DNA was enriched in expressed genes, while in the breast cancer cells, it was enriched in non-expressed genes. In both cell lines, the chromatin modifications that mark transcriptional activation or repression were appropriately associated with gene expression. Using this new MAR-Seq approach, we provide the first genome-wide characterization of nuclear matrix attachment in mammalian cells and reveal that the nuclear matrixassociated genome is highly cell-context dependent.
Identifying Nuclear Matrix-Attached DNA Across the Genome.
Specimen part, Cell line
View SamplesAnalysis of lineage depleted human cord blood cells sequentially transduced with retro- (BCR-ABL1) and lentiviral (Ik6) vectors and the corresponding controls. Results provide important informations on the collaboration of BCR-ABL1 and Ik6 in human hematopoietic cells.
Dominant-negative Ikaros cooperates with BCR-ABL1 to induce human acute myeloid leukemia in xenografts.
Specimen part
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