Whole transcriptome analysis of reaggregated embryoid bodies treated with IWR-1
ABSTRACT: We identified distict mesodermal sub-populations based on Endoglin (Eng) and Flk1 expression in Brachyury (Bry) positive cells. By using whole-transcriptome analysis, we further characterized these populations and how they changed when Wnt pathway is inhibited Reaggregates mRNA profiles of unsorted, Flk1+ Eng+, and Flk1- Eng+ samples were generated by deep sequencing, in triplicate , using Ilumina.
Project description:We have developed a protocol to generate cardiopharyngeal mesoderm (CPM) in vitro by Mesp1 induction in ES cells. The goal of this study is to compare the transcriptome of CPM-derived cardiac and skeletal myogenic progenitors to identify novel lineage-specific markers. mRNA profiles of CPM-derived D6 (early) and D12 (late), cardiac (BMP) and skeletal myogenic (control) progenitors were generated
Project description:Much remains unknown about the signals that induce early mesoderm to initiate hematopoietic differentiation. Here we show that endoglin (Eng), a receptor for the TGFβ superfamily, identifies all cells with hematopoietic fate in the early embryo. These arise in an Eng+Flk1+ mesodermal precursor population at E7.5, a cell fraction also endowed with endothelial potential. In Eng knockout embryos, hematopoietic colony activity and numbers of CD71+Ter119+ erythroid progenitors were severely reduced. This coincided with severely reduced expression of embryonic globin and key BMP target genes including the hematopoietic regulators Scl, Gata1, Gata2 and Msx-1. To interrogate molecular pathways active in the earliest hematopoietic progenitors, we applied transcriptional profiling to sorted cells from E7.5 embryos. Eng+Flk-1+ progenitors co-expressed TGFβ and BMP receptors and target genes. Furthermore, Eng+Flk-1+ cells presented high levels of phospho-SMAD1/5, indicating active TGFβ and/or BMP signaling. Remarkably, under hematopoietic serum-free culture conditions, hematopoietic outgrowth of endoglin-expressing cells was dependent on TGFβ superfamily ligands: BMP4, BMP2, or TGF-β1. These data demonstrate that the E+F+ fraction at E7.5 represents mesodermal cells competent to respond to TGFb1, BMP4, or BMP2, shaping their hematopoietic development, and that endoglin is a critical regulator in this process by modulating TGF/BMP signaling. E7.5 pooled embryos (25 litters; 300 embryos approximately) were dissected and 3,000 cells were sorted in triplicate for Eng-Flk1-, Eng-Flk1+, Eng+Flk1+, and Eng+Flk1- fractions. Microarray results were analyzed with GeneSpring GX software.
Project description:Mutations within genes encoding spliceosomal proteins are the most common class of mutations in patients with myelodysplastic syndromes, yet it is currently not well understood how these mutations impact hematopoiesis or RNA splicing. Here we report that mutations affecting the splicing factor SRSF2 alter its normal RNA recognition activity, resulting in impaired hematopoietic differentiation and myelodysplasia. Commonly occurring SRSF2 mutations impaired wildtype SRSF2’s normal RNA-binding avidity and preference for specific exonic splicing enhancer RNA motifs. Integration of murine and human transcriptome data identified recurrent mis-splicing of key transcriptional regulators in the presence of mutant SRSF2, including promotion of a highly conserved “poison” exon of EZH2 that results in nonsense-mediated decay and contributes to impaired hematopoiesis. These data provide a mechanistic basis for the enrichment of specific mutations in spliceosomal proteins in myelodysplasia, and suggest that altered RNA recognition activity is a novel mechanism of leukemogenesis. mRNA profiles of murine model and K562 cells expressing SRSF2 WT, mutants and knockdown of SRSF2 in TF-1 cells generated by deep sequencing.
Project description:Different combinations of Endoglin tissue specific enhancers define hemangioblast and hemogenic endothelium cell fractions Overall design: We generated a series of embryonic stem cell lines, each targeted with reporter constructs driven by tissue specific promoter/enhancer combinations of Endoglin (ENG). The Eng promoter (P) when combined with the -8/+7/+9kb enhancers targeted cells in FLK1 mesoderm that were enriched for blast colony forming potential, whereas the P/-8kb enhancer targeted TIE2+/c-KIT+/CD41- HE cells that were enriched for hematopoietic potential. These cell fractions were isolated and their transcriptomes profiled by RNA-seq.
Project description:Whole-exome sequencing studies have identified common mutations affecting genes encoding components of the RNA splicing machinery in hematological malignancies. Here, we sought to determine how mutations affecting the 3' splice site recognition factor U2AF1 altered its normal role in RNA splicing. We find that U2AF1 mutations influence the similarity of splicing programs in leukemias, but do not give rise to widespread splicing failure. U2AF1 mutations cause differential splicing of hundreds of genes, affecting biological pathways implicated in myeloid disease such as DNA methylation (DNMT3B), X chromosome inactivation (H2AFY), the DNA damage response (ATR, FANCA), and apoptosis (CASP8). We show that U2AF1 mutations alter the preferred 3' splice site motif in vivo, in cell culture, and in vitro. Mutations affecting the first and second zinc fingers give rise to different alterations in splice site preference and largely distinct downstream splicing programs. These allele-specific effects are consistent with a computationally predicted model of U2AF1 in complex with RNA. Our findings suggest that U2AF1 mutations contribute to pathogenesis by causing quantitative changes in splicing that affect diverse cellular pathways, and give insight into the normal function of U2AF1’s zinc finger domains. mRNA profiles of K562 cells expressing U2AF1 WT, mutants and knockdown of U2AF1 generated by deep sequencing.
Project description:Aging of immune organs, termed as immunosenescence, is suspected to promote systemic inflammation and age-associated disease. The cause of immunosenescence and how it promotes disease, however, has remained unexplored. We report that the Drosophila fat body, a major immune organ, undergoes immunosenescence and mounts strong systemic inflammation that leads to de-regulation of immune deficiency (IMD) signaling in the midgut of old animals. Inflamed old fat bodies secrete circulating peptidoglycan recognition proteins that repress IMD activity in the midgut, thereby promoting gut hyperplasia. Further, fat body immunosenecence is caused by ageassociated lamin-B reduction specifically in fat body cells, which then contributes to heterochromatin loss and de-repression of genes involved in immune responses. As lamin-associated heterochromatin domains are enriched for genes involved in immune response in both Drosophila and mammalian cells, our findings may provide insights into the cause and consequence of immunosenescence during aging. 17 samples from the fat body, the midgut, or the whole gut with different ages or RNAi treatment. 6 of the samples were wildtype young control. For each experiment, we had two or three biological replicates.
Project description:We found that mouse ES cell-derived Flk1+ cells could be subdivided into three population by the expression of PDGFRa and CAR (Flk1+PDGFRa-CAR-, Flk1+PDGFRa-CAR+, and Flk1+PDGFRa+CAR+). Therefore, global gene expression analysis was perfomed by microarray to characterize these mesodermal subsets. RNA isolated from five separate experiments was pooled and used for comparison
Project description:This study uses Whole Transcriptome Shotgun Sequencing (RNA-Seq) data to interrogate the developmental dynamics of the C57BL/6 mouse liver transcriptome. We analyze gene expression patterns in the developing mouse liver over 12 distinct time points from late embryonic stage (2 days before birth) to maturity (60 days after birth). Biological functions deemed significant at different developmental stages are identified and their leverage is mapped over time. Upstream regulators modulating these gene expression patterns are determined and their regulatory networks are described along with putative transcriptional modules associated with gene regulation. Several genes that were alternatively spliced over time were identified. Previously uncharacterized isoforms were found for several genes. We analyze gene expression patterns in the developing mouse liver over 12 distinct time points from late embryonic stage (2 days before birth) to maturity (60 days after birth). Three replicates per time point.
Project description:ES cells differentiated in the presence of the Wnt inhibitor DKK1 fail to express the transcription factor Snail and undergo EMT or mesoderm differentiation. We generated an ES cell line, A2.snail, that induced Snail expression upon addition of doxycycline addition. Microarrays were used to gain a global picture of Flk1- and Flk1+ cells generated one day after Snail was expressed during Wnt inhibition. A2.snail ES cells, which express Snail upon addition of doxycycline, were differentiated as embryoid bodies in differentiation media and DKK1. Snail-induced cultures uniquely develop a select population of Flk1+ cells. Total RNA was harvested from sorted control (no doxycycline) Flk1- cells and sorted Snail-induced (doxycycline at day 2) Flk1- and Flk1+ cells at day 3 of differentiation.
Project description:Snai1 is a master factor of epithelial to mesenchymal transitioin (EMT), however, its role in embryonic stem cell (ESC) differentiation and lineage commitment remains undefined. We used microarrays to compare the global programme of gene expression between control and Snai1 knockout Flk1+ and Flk1- cells sorted from 4 day EBs. Control and Snai1 knockout ESCs were cultured as embryoid bodies in spotaneous differentiation media, 4 days EBs were dissociated and sorted by anti-Flk1 antibody to separated Flk1+ and Flk1- cells, total RNA were collected for Affymetrix microarrays