Transcriptome analysis of adult hematopoietic stem cells (HSC) and their progeny has informed our understanding of blood differentiation and leukemogenesis, but a similarly transformative analysis of the embryonic origins of hematopoiesis is lacking. To address this issue, we acquired gene expression profiles of developing HSC purified from over 2500 dissected murine embryos and adult mice, and applied a network biology-based analysis to reconstruct the gene regulatory networks of sequential stages of HSC development. We found that embryonic hematopoietic elements clustered into three distinct transcriptional states characteristic of the definitive yolk sac, HSCs emerging from hemogenic endothelium, and definitive HSCs. We functionally validated several candidate transcriptional regulators of HSC ontogeny by morpholino-mediated knock-down in zebrafish embryos, confirming changes in the expression of HSC markers runx1 and c-myb in the aorta-gonads-mesonephros (AGM), the site of definitive HSC specification. Moreover, we found that HSCs derived from differentiating embryonic stem cells in vitro (ESC-HSC) most closely resemble definitive HSC, yet lack a signature indicative of specification by Notch signaling, which likely accounts for their deficient lymphoid development. Our analysis and accompanying web resource will accelerate the characterization of regulators of HSC ontogeny, facilitate efforts to direct hematopoietic differentiation and cell fate conversion, and serve as a model to study the origins of other adult stem cells.
The transcriptional landscape of hematopoietic stem cell ontogeny.
Specimen part
View SamplesHaematopoietic stem and progenitor cell (HSPC) transplant is a widely used treatment for life-threatening conditions including leukemia; however, the molecular mechanisms regulating HSPC engraftment of the recipient niche remain incompletely understood. Here, we developed a competitive HSPC transplant method in adult zebrafish, using in vivo imaging as a non-invasive readout. We used this system to conduct a chemical screen and identified epoxyeicosatrienoic acids (EET) as a family of lipids that enhance HSPC engraftment. EETs’ pro-haematopoietic effects are conserved in the developing zebrafish, where this molecule promotes HSPC specification through activating a unique AP-1/runx1 transcription program autonomous to the haemogenic endothelium. This effect requires the activation of PI3K pathway, specifically PI3Kg. In adult HSPCs, EETs induce transcriptional programs including AP-1 activation, modulating multiple cellular processes, such as migration, to promote engraftment. Finally, we demonstrated that the EET effects on enhancing HSPC homing and engraftment are conserved in mammals. Our study established a novel method to explore the molecular mechanisms of HSPC engraftment, and discovered a previously unrecognized, evolutionarily conserved pathway regulating multiple haematopoietic generation and regeneration processes. EETs may have clinical application in marrow or cord blood transplantation. Overall design: To analyze the effect of 11,12-EET on gene expression of human blood cells, we treated human CD34+ cells (positively selected from cord blood) and the human leukemic cell line U937 with 5uM 11,12-EET for 2 hrs. Control treatment was done with DMSO.
Epoxyeicosatrienoic acids enhance embryonic haematopoiesis and adult marrow engraftment.
No sample metadata fields
View SamplesAlthough Hematopoietic Stem Cell Transplantation (HSCT) routinely treats hematologic disease, many patients experience adverse outcomes. Understanding the molecular regulation of HSC engraftment is paramount to improving HSCT regimens. Here, we executed a large-scale transplant-based functional screen for novel regulators of HSC repopulation.. Of >50 gene candidates tested, 18 were required for in vivo hematopoietic repopulation and two were detrimental to repopulation, as their loss enhanced this activity. Each Hit was validated in a second screen. Eleven Hits have never before been implicated in HSC biology. We further show that one novel Hit, Foxa3, is required for optimal engraftment as Foxa3-/- bone marrow is defective in both primary and secondary hematopoietic reconstitution. We also present evidence that Foxa3 is a novel pioneer factor in HSC. Each gene identified in our screen is a window into the cellular mechanisms that control hematopoietic reconstitution. Thus, this work represents a resource to the community to better understand these processes
Functional screen identifies regulators of murine hematopoietic stem cell repopulation.
Specimen part
View SamplesTo obtain a comprehensive view of genes contributing to long-term memory we performed mRNA sequencing from single Drosophila heads following behavioral training that produces long-lasting memory. Overall design: Drosophila trained with an appetitive conditioning paradigm using Sucrose were collected prior to starvation, training, and 1 or 4 hours post-training, 5 to 6 replicates each, for RNA-Seq analysis of the fly heads with an Illumina HiSeq 2000.
Antimicrobial peptides modulate long-term memory.
Specimen part, Subject
View SamplesGenome-wide profiling establishes that human cytomegalovirus (HCMV) exerts an extensive, unforeseen level of specific control over which cellular mRNAs are recruited to or excluded from polyribosomes.
Global reprogramming of the cellular translational landscape facilitates cytomegalovirus replication.
Specimen part, Disease, Treatment
View SamplesThe capability to detect target organ toxicity as well as to determine the molecular mechanisms underlying such toxicity by employing surrogate biospecimens that can be obtained by a non-invasive or minimally invasive procedure has significant advantage in occupational toxicology. Pulmonary toxicity and global gene expression profile in the lungs, peripheral blood and bronchoalveolar lavage (BAL) cells were determined in rats at 44-weeks following pulmonary exposure to crystalline silica (15 mg/m3, 6-hours/day, 5 days). A significant elevation in lactate dehydrogenase activity and albumin content observed in the BAL fluid suggested the induction of pulmonary toxicity in the silica exposed rats. Similarly, the observation of histological alterations, mainly type II pneumocyte hyperplasia and fibrosis, in the lungs further confirmed silica-induced pulmonary toxicity in the rats. A significant increase in the number of neutrophils and elevated monocyte chemotactic protein 1 level in the BAL fluids suggested silica-induced pulmonary inflammation in the rats. Determination of global gene expression profile in the lungs, BAL cells, and peripheral blood of the silica exposed rats identified 144, 236, and 51 significantly differentially expressed genes (SDEGs), respectively, compared with the corresponding control samples. Bioinformatics analysis of the SDEGs demonstrated a remarkable similarity in the biological functions, molecular networks and canonical pathways that were significantly affected by silica exposure in the lungs, BAL cells and blood of the rats. Induction of inflammation was identified, based on the bioinformatics analysis of the significantly differentially expressed genes in the lungs, blood and BAL cells, as the major molecular mechanism underlying the silica-induced pulmonary toxicity. The findings of our study demonstrated the potential application of global gene expression profiling of peripheral blood and BAL cells as a valuable minimally invasive approach to study silica-induced pulmonary toxicity in rats.
Molecular mechanisms of pulmonary response progression in crystalline silica exposed rats.
Sex, Specimen part, Time
View SamplesMicroarray-based expression profiling of BRCA2 knockout and isogenic wild type HCT116 human colorectal cancer cells
Up-regulation of the interferon-related genes in BRCA2 knockout epithelial cells.
Cell line
View SamplesC2C12 myoblasts were infected with a retrovirus expressing Pax7d or with an empty virus (puro) as a control. All of the samples originated from the same common pool of parental C2C12. This pool was split into six streams. A single prep of Pax7d-puro virus was split into three volumes and used to infect three of the streams. A single prep of puro-alone virus was similarly split in three and used to infect the remaining three streams. From the point of the infection forward each stream was maintained distinct from the others. Cells were infected and grown simultaneously under identical conditions.
Pax7 activates myogenic genes by recruitment of a histone methyltransferase complex.
No sample metadata fields
View SamplesMurine gliomblastoma tumor progenitor cells TPCs with high and low EGFRvIII activity, pEGFR-Hi and pEGFR-Lo, showed differences in proliferation, differentiation, and invasion. Zs-Green-expressing
GBM heterogeneity as a function of variable epidermal growth factor receptor variant III activity.
Specimen part
View SamplesWe compared the gene expression of A549 cells following 24 and 48 hours of treatment with a no-observed-effect level dose of cisplatin. The objective of the study is to identify genes that are differentially expressed in response to sub-lethal doses of cisplatin. This study helps identify not only treatment responses but also changes in gene expression that may confer cytoprotective mechanisms that allow these cells to survive treatment and to develop treatment resistance.
Combined Use of Gene Expression Modeling and siRNA Screening Identifies Genes and Pathways Which Enhance the Activity of Cisplatin When Added at No Effect Levels to Non-Small Cell Lung Cancer Cells In Vitro.
Cell line, Treatment, Time
View Samples