The cellular origin and molecular progression towards aggressive cancers such as acute myeloid leukemia (AML) remain elusive. Clinically, Myelodysplastic syndromes (MDS) and related myeloproliferative neoplasias (MPN) disorders1-5 are believed to present as a precursor stage to lethal AML development. Despite the identification of cytogenetic abnormalities and increased activation of signaling in human MDS/MPN, specific pathways that either sustain or initiate disease progression and evolve into self-sustaining leukemic-initiating cells (L-ICs)13 have not been elucidated. Here we demonstrate that tissue specific loss of glycogen synthase kinase-3 (GSK3 beta) initiates the emergence of stable Pre-leukemic-ICs (PLIC) in vivo. In contrast to deletion or transgenic perturbation of pathways associated with AML eg. -catenin/Wnt, serial transplantation of PL-IC produced abnormal hematological disease that phenotypically and molecularly resembles human MDS/MPN. PL-ICs were exclusively generated from GSK3 beta deficient hematopoietic stem cells (HSCs), indicating that disease initiation events collaborate with existing HSC self-renewal machinery. In the absence of GSK3 beta, subsequent deletion of GSK3 beta caused rapid induction of L-ICs that give rise to lethal AML. As these processes were solely driven by dose-dependent deficiencies in GSK3 beta levels, our results suggest that perturbation of this pathway can sufficiently drive and recapitulate a step-wise progression of disease from HSCs to MDS/MPN and subsequent AML. Our study provides a molecular and cellular foundation to understand AML evolution from pre-leukemic precursors. We suggest that defining the molecular states of pre-neoplastic disease will allow patient stratification at early stages of MDS/MPN onset and aid in the development of therapeutic targeting of causal pathways responsible for the earliest stages of leukemic initiation events.
GSK3 Deficiencies in Hematopoietic Stem Cells Initiate Pre-neoplastic State that Is Predictive of Clinical Outcomes of Human Acute Leukemia.
Sex, Specimen part
View SamplesThe two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in misregulated expression of imprinted genes and hypomethylation of corresponding imprinted loci. Treatment of wild-type ESCs with small molecule inhibitors of Gsk-3 phenocopies the DNA hypomethylation of imprinted loci observed in Gsk-3 null ESCs. We provide evidence that DNA hypomethylation in Gsk-3 null ESCs is due to a reduction in the levels of the de novo DNA methyltransferase, Dnmt3a2.
Phosphatidylinositol 3-kinase (PI3K) signaling via glycogen synthase kinase-3 (Gsk-3) regulates DNA methylation of imprinted loci.
Specimen part
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 Samples