RNA editing is a mutational mechanism that specifically alters the nucleotide content in sets of transcripts while leaving their cognate genomic blueprint intact. Editing has been detected from bulk RNA-seq data in thousands of distinct transcripts, but apparent editing rates can vary widely (from under 1% to almost 100%). These observed editing rates could result from approximately equal rates of editing within each individual cell in the bulk sample, or alternatively, editing estimates from a population of cells could reflect an average of distinct, biologically significant editing signatures that vary substantially between individual cells in the population. To distinguish between these two possibilities we have constructed a hierarchical Bayesian model which quantifies the variance of editing rates at specific sites using RNA-seq data from both single cells and a cognate bulk sample consisting of ~ 106 cells. The model was applied to data from murine bone-marrow derived macrophages and dendritic cells, and predicted high variance for specific edited sites in both cell types tested. We then 1 validated these predictions using targeted amplification of specific editable transcripts from individual macrophages. Our data demonstrate substantial variance in editing signatures between single cells, supporting the notion that RNA editing generates diversity within cellular populations. Such editing-mediated RNA-level sequence diversity could contribute to the functional heterogeneity apparent in cells of the innate immune system. Overall design: 26 samples were subjected to RNA-seq: 24 single WT macrophages, and 2 bulk samples (Apobec1 WT and KO macrophages), consisting of 500,000-1 million cells each.
RNA editing generates cellular subsets with diverse sequence within populations.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
ZFP36L2 is required for self-renewal of early burst-forming unit erythroid progenitors.
Specimen part
View SamplesEarly erythroid progenitors were isolated from mouse E14.5 fetal liver. After cell lysing, control IgG or RBP specific antibody were incubated with cell lysis. Immunoprecipitation followed by microarray experiments were carried out to identify transcripts that are immunoprecipitated by either control IgG or RBP specific antibody.
ZFP36L2 is required for self-renewal of early burst-forming unit erythroid progenitors.
Specimen part
View SamplesThe Notch signalling pathway plays fundamental roles in diverse developmental processes in metazoans, where it is important in driving cell fate and directing differentiation of various cell types. However, we still have limited knowledge about the role of Notch in early preimplantation stages of mammalian development, or how it interacts with other signalling pathways active at these stages such as Hippo. By using genetic and pharmacological tools in vivo, together with image analysis of single embryos and pluripotent cell culture, we have found that Notch is active from the 4-cell stage. Transcriptomic analysis in single morula identified novel Notch targets, such as early naïve pluripotency markers or transcriptional repressors such as TLE4. Our results reveal a previously undescribed role for Notch in driving transitions during the gradual loss of potency that takes place in the early mouse embryo prior to the first lineage decisions. Overall design: Transcriptomic analysis comparing single Rbpj mutant and control mouse morulae. RNA was isolated from individual E2.5 embryos from two litters. 3 mutant and 3 control embryos were used for analysis.
Transitions in cell potency during early mouse development are driven by Notch.
Specimen part, Subject
View SamplesWe have generated “reprogrammable” transgenic mice that ubiquitously express the four Yamanaka factors in an inducible manner. Transitory induction of the transgene results in multiple teratomas emerging from a variety of organs, thus indicating that full reprogramming into iPSCs can occur in vivo. By performing bone marrow transplant experiments, we demonstrate that both hematopoietic cells, as well as non-hematopoietic cells can be reprogrammed in vivo. Remarkably, reprogrammable mice also present circulating iPSCs in the bloodstream (in vivo-iPSCs) with all the expected properties of bona fide iPSCs. Moreover, in contrast to in vitro-iPSCs or embryonic stem cells (ESCs), in vivo-iPSCs have an increased capacity to undergo trophectoderm lineage differentiation, which suggests that in vivo-iPSCs are more plastic or primitive than in vitro-generated iPSCs or ESCs. Overall design: 6 clones of in vivo-generated iPSCs, 5 indendent clones of in vitro-generated iPSCs, and 3 clones of established ESCs
Reprogramming in vivo produces teratomas and iPS cells with totipotency features.
Specimen part, Cell line, Subject
View SamplesOrganophosphorus compounds may induce neurotoxicity through mechanisms other than the cholinergic pathway, which need to be unraveled by a comprehensive and systematic approach such as genome-wide gene expression analysis.
Toxicogenomic studies of human neural cells following exposure to organophosphorus chemical warfare nerve agent VX.
Specimen part
View SamplesTranscriptome analysis by RNAseq of leukemia model promoted by MLL-Af4 or MLL-AF9 fusion proteins. We find each fusion protein promotes a specific gene signature correlating to those identified in patients Overall design: Human CD34+ hematopoietic stem and progenitor cells were transduced with retrovirus expressing MLL-Af4 or MLL-AF9. Transduced cells were transplanted into immunodeficient mice to induce lymphoid leukemia or placed in myeloid in vitro culture. CD19+ lymphoid leukemia cells (3 AF9, 6 Af4), control health CD19+CD34+ proB cells (n=3) and 4 pairs of Af4 and AF9 CD33+CD19- myeloid culture cells were collected for RNA-seq
Instructive Role of MLL-Fusion Proteins Revealed by a Model of t(4;11) Pro-B Acute Lymphoblastic Leukemia.
No sample metadata fields
View SamplesLung cancer is the leading cause of cancer related mortality worldwide, with non-small cell lung cancer (NSCLC) as the most prevalent form. Despite advances in treatment options including minimally invasive surgery, CT-guided radiation, novel chemotherapeutic regimens, and targeted therapeutics, prognosis remains dismal. Therefore, further molecular analysis of NSCLC is necessary to identify novel molecular targets that impact prognosis and the design of new-targeted therapies. In recent years, tumor “activated/reprogrammed” stromal cells that promote carcinogenesis have emerged as potential therapeutic targets. However, the contribution of stromal cells to NSCLC is poorly understood. Here, we show increased numbers of bone marrow (BM)-derived hematopoietic cells in the tumor parenchyma of NSCLC patients compared with matched adjacent non-neoplastic lung tissue. By sorting specific cellular fractions from lung cancer patients, we compared the transcriptomes of intratumoral myeloid compartments within the tumor bed with their counterparts within adjacent non-neoplastic tissue from NSCLC patients. The RNA sequencing of specific myeloid compartments (immature monocytic myeloid cells and polymorphonuclear neutrophils) identified differentially regulated genes and mRNA isoforms, which were inconspicuous in whole tumor analysis. Genes encoding secreted factors, including osteopontin (OPN), chemokine (C-C motif) ligand 7 (CCL7) and thrombospondin 1 (TSP1) were identified, which enhanced tumorigenic properties of lung cancer cells indicative of their potential as targets for therapy. This study demonstrates that analysis of homogeneous stromal populations isolated directly from fresh clinical specimens can detect important stromal genes of therapeutic value. Overall design: We sorted pure populations of the immature monocytic myeloid cells (IMMCs), neutrophils (Neu), and epithelial cells (Epi) from tumors and adjacent lung tissues of stage I-III lung adenocarcinoma patients. RNA samples (totally 17 samples) were sequenced: from tumor IMMC (n=3), Neu (n=2), Epi (n=2); from adjacent lung IMMC (n=3), Neu (n=4), Epi (n=3).
Identification of Reprogrammed Myeloid Cell Transcriptomes in NSCLC.
No sample metadata fields
View SamplesIschemic cardiopathy is the leading cause of death in the world, for which efficient regenerative therapy is not currently available. In mammals, after a myocardial infarction episode, the damaged myocardium is replaced by scar tissue featuring collagen deposition and tissue remodelling with negligible cardiomyocyte proliferation. Zebrafish, in contrast, display an extensive regenerative capacity as they are able to restore completely lost cardiac tissue after partial ventricular amputation. Due to the lack of genetic lineage tracing evidence, it is not yet clear if new cardiomyocytes arise from existing contractile cells or from an uncharacterised set of progenitors cells. Nonetheless, several genes and molecules have been shown to participate in this process, some of them being cardiomyocyte mitogens in vitro. Though questions as what are the early signals that drive the regenerative response and what is the relative role of each cardiac cell in this process still need to be answered, the zebrafish is emerging as a very valuable tool to understand heart regeneration and devise strategies that may be of potential value to treat human cardiac disease. Here, we performed a genome-wide transcriptome profile analysis focusing on the early time points of zebrafish heart regeneration and compared our results with those of previously published data. Our analyses confirmed the differential expression of several transcripts, and identified additional genes the expression of which is differentially regulated during zebrafish heart regeneration. We validated the microarray data by conventional and/or quantitative RT-PCR. For a subset of these genes, their expression pattern was analyzed by in situ hybridization and shown to be upregulated in the regenerating area of the heart. The specific role of these new transcripts during zebrafish heart regeneration was further investigated ex vivo using primary cultures of zebrafish cardiomyocytes and/or epicardial cells. Our results offer new insights into the biology of heart regeneration in the zebrafish and, together with future experiments in mammals, may be of potential interest for clinical applications.
Transcriptomics approach to investigate zebrafish heart regeneration.
Specimen part, Time
View SamplesInhibition of miR-33 results in increased cholesterol efflux and HDL-cholesterol levels in mice. In this study we examined the effect of miR-33 inhibition in a mouse model of atherosclerosis and observed significant reduction in atherosclerotic plaque size. At the end of the study, gene expression in macrophages from the atherosclerotic plaques was assessed.
Antagonism of miR-33 in mice promotes reverse cholesterol transport and regression of atherosclerosis.
Sex, Specimen part
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