O-linked β-N-acetylglucosamine (O-GlcNAc) acts as a glucose sensor to epigenetically regulate the insulin gene in pancreatic beta cells
ABSTRACT: We compare global gene expression changes in the Min6 cell line in response to altered glucose flux and pharmacological manipulation of the O-GlcNAc postranslational protein modification. Min6 cells were treated for 1hr in the following conditions: Low glucose (LG), high glucose (HG) and LG+GlcNAcstatin (LG+GNS). After treatment, total RNA was extracted and used for sequencing.
Project description:An X-chromosome exome sequencing analysis identified a mutation in O-GlcNAc transferase (OGT) (pL254F) in a family with X-linked intellectual disability (XLID). Affected patient lymohoblastoids exhibit decreased steady state OGT levels owing to an unstable protein compared to the unaffected, related male controls. Suprisingly, global O-GlcNAc levels remained remained unaltered. This prompted us to check the both protein and mRNA levels of the other cycling enzyme, O-GlcNAcase (OGA) which was also lowered. This implies that a compensation mechanism exists, however imperfect, owing to the disease state of the individuals. We performed glabal transcriptome analysis to assess any other changes in message between patients and controls. Our study highlights small differences in the global transcriptome of patient lymhoblastoids that have the L254F mutation in O-GlcNAc transferase when compared to familial controls using Illumina sequencing of total RNA
Project description:Distinct shaping of the upper versus lower facial skeleton is essential for function of the vertebrate jaw and middle ear, yet the cellular mechanisms by which this occurs have remained unclear. Here, we show that Endothelin1 (Edn1) signaling accelerates mesenchymal condensation and subsequent cartilage formation in the lower face through antagonism of Jagged-Notch signaling and Prrx1 transcription factors. A genomic analysis of facial skeletal precursors in mutants and overexpression embryos reveals that Jagged-Notch signaling represses genes that are strongly induced as pharyngeal arch neural crest-derived cells begin skeletal differentiation. In wild types, initial Jagged-Notch repression dorsally ensures that barx1+ condensations and cartilage differentiation occur first in ventral-intermediate zones of the pharyngeal arches. Reduced Jagged-Notch signaling results in an expansion of pre-cartilage condensations in the upper face, with loss of barx1 partially restoring dorsal cartilage shapes in jag1b mutants. Further, by studying new mutants for zebrafish prrx1a and prrx1b, we find that Prrx1 genes function in parallel to Jagged-Notch signaling to restrict the formation of dorsal barx1+ pre-cartilage condensations. Consistently, combined losses of jag1b and prrx1a/b robustly rescue ventral barx1+ condensations and lower facial cartilage development in edn1 mutants. Together, our work suggests that Edn1 works through parallel inhibition of Jagged-Notch and Prrx1 pathways to promote an earlier and more extensive establishment of cartilage condensations in the lower face. We performed RNAseq on FACS-sorted neural crest-derived pharyngeal arch cells (fli1a:GFP; sox10:DsRed double positive) from wild-type embryos at 3 different stages (20, 28, and 36 hours post fertilization) and embryos with altered levels of Edn1 and Notch signaling (edn1 mutants and hsp70I:Gal4; UAS:Edn1 transgenics; jag1b mutants, dibenzazepine-treated embryos, and hsp70I:Gal4; UAS:NICD transgenics. We also sequenced RNA from heat-shocked UAS:Edn1+ and hsp70I:Gal4+ transgenics and jag1b+/+ controls.
Project description:During development histone modifying enzymes are required for cell identity and lineage commitment, however little is known about the regulatory origins of the epigenome during embryonic development. Here we generate a comprehensive set of embryonic epigenome reference maps, which we use to determine the extent to which maternal factors shape chromatin state in Xenopus embryos. Using α-amanitin to inhibit zygotic transcription, we find that the majority of H3K4me3 and H3K27me3-enriched regions form a maternally defined epigenetic regulatory space with an underlying logic of hypomethylated islands. This maternal regulatory space extends to a substantial proportion of neurula stage-activated promoters. In contrast, p300-recruitment to distal regulatory regions requires embryonic transcription at most loci. The results show that H3K4me3 and H3K27me3 are part of a regulatory space that exerts an extended maternal control well into post-gastrulation development, and highlight the combinatorial action of maternal and zygotic factors through proximal and distal regulatory sequences. We have performed ChIP-sequencing of eight histone modifications, RNA polymerase II (RNAPII) and the enhancer protein p300 at five stages of development: blastula (st. 9), gastrula (st. 10.5, 12.5), neurula (st. 16) and tailbud (st. 30). These experiments allow identification of enhancers (H3K4me1, p300), promoters (H3K4me3, H3K9ac), transcribed regions (H3K36me3, RNAPII) and repressed and heterochromatic domains (H3K27me3, H3K9me2, H3K9me3, H4K20me3). In addition we generated pre-MBT (st. 8) maps for three histone modifications (H3K4me3, H3K9ac, H3K27me3) and single-base resolution DNA methylome maps using whole genome bisulfite sequencing of blastula and gastrula (st. 9 and 10.5) embryos. To determine the maternal and zygotic contributions to chromatin state, we used alpha-amanitin to block embryonic transcription. Fertilised eggs were injected with 2.3 nl of 2.67 ng/ul alpha-amanitin and developed until the control embryos reached mid-gastrulation. Alpha-amanitin and control embryos were used for RNA-seq and ChIP-seq of RNAPII, H3K4me3, H3K27me3 and p300. For all ChIP-seq samples of the epigenome reference maps and RNAPII ChIP-seq samples of the α-amanitin experiments three biological replicates of different chromatin isolations of 45 embryos were pooled. Two biological replicates for H3K4me3 (α-amanitin injected: resp. 90 and 56 embryo equivalents (eeq); control: resp. 45 and 67 eeq), H3K27me3 (α-amanitin injected: resp. 90 and 180 eeq; control: resp. 45 and 202 eeq) and p300 (α-amanitin injected: resp. 112 and 56 eeq; control: resp. 112 and 67 eeq) ChIP-seq samples of the α-amanitin experiments were generated. For RNA-seq samples of the α-amanitin experiments RNA from 5 embryos from one biological replicate was isolated and depleted of ribosomal RNA
Project description:Phoenix dactylifera seedlings were exposed to heat, drought and combined heat & drought conditions in growth chambers. Leaf samples were collected for total RNA isolation (RNAseq, Illumina HiSeq 1000), and water soluble metabolites. The RNAseq of four biological replicates (two individuals per replicate) were compared against the control condition. Transcriptomics data suggests the combine heat and drought resembled heat response, whereas drought resembled more to control. The hallmarks of heat stress were visible in the transcriptomics data, such as protein misfolding, response to hydrogen peroxide and cell wall modification, as well as ABA signaling in the case of drought. Since the plants were exposed to the stress for several days before harvesting, the early signs of heat stress such as calcium and NO signaling were not detected anymore. In addition, data suggest a significant enrichment of circadian rhythm motifs in the differentially expressed genes in heat and combined heat and drought stresses, suggesting new stress avoidance strategies.
Project description:Pancreatic islet endocrine cell and endothelial cell (EC) interactions mediated by vascular endothelial growth factor-A (VEGF-A) signaling are important for islet endocrine cell differentiation and the formation of highly vascularized islets. To dissect how VEGF-A signaling modulates intra-islet vasculature and innervation, islet microenvironment, and β cell mass, we transiently increased VEGF-A production by β cells. VEGF-A induction dramatically increased the number of intra-islet ECs but led to β cell loss. After withdrawal of the VEGF-A stimulus, β cell mass, function, and islet structure normalized as a result of a robust, but transient, burst in proliferation of pre-existing β cells. Bone marrow-derived macrophages (MΦs) recruited to the site of β cell injury were crucial for the β cell proliferation, which was independent of pancreatic location and circulating factors such as glucose. Identification of the signals responsible for the proliferation of adult, terminally differentiated β cells will improve strategies aimed at β cell regeneration and expansion. Examination of RNA profiles from isolated whole islets from RIP-rtTA; TetO-VEGF-A mice with no doxycycline (Dox) treatment (3 samples) and after 1 week of Dox (3 sample); and islet-derived macrophages (3 samples) and endothelial cells (3 samples) isolated from dispersed purified islets from RIP-rtTA; TetO-VEGF-A mice after 1 week Dox treatment by fluorescence-activated cell sorting using antibodies against CD11b and CD31, respectively.
Project description:Although technological advances now allow increased tumor profiling, a detailed understanding of the mechanisms leading to the development of different cancers remains elusive. Our approach towards understanding the molecular events that lead to cancer is to characterize changes in transcriptional regulatory networks between normal and tumor tissue. Because enhancer activity is thought to be critical in regulating cell fate decisions, we have focused our studies on distal regulatory elements and transcription factors that bind to these elements. Using DNA methylation data, we identified more than 25,000 enhancers that are differentially activated in breast, prostate, and kidney tumor tissues, as compared to normal tissues. We then developed an analytical approach called TENET (Tracing Enhancer Networks using Epigenetic Traits) that correlates DNA methylation levels at enhancers with gene expression to identify more than 800,000 genome-wide links from enhancers to genes and from genes to enhancers. We found more than 1,200 transcription factors to be involved in these tumor-specific enhancer networks. We further characterized several transcription factors linked to a large number of enhancers in each tumor type, including GATA3 in non-basal breast tumors, HOXC6 and DLX1 in prostate tumors, and ZNF395 in kidney tumors. We showed that HOXC6 and DLX1 are associated with different clusters of prostate tumor-specific enhancers and confer distinct transcriptomic changes upon knockdown in C42B prostate cancer cells. We also discovered de novo motifs enriched in enhancers linked to ZNF395 in kidney tumors. Our studies characterized tumor-specific enhancers and revealed key transcription factors involved in enhancer networks for specific tumor types and subgroups. Our findings, which include a large set of identified enhancers and transcription factors linked to those enhancers in breast, prostate, and kidney cancers, will facilitate understanding of enhancer networks and mechanisms leading to the development of these cancers. Examination of FAIRE and ChIP assays in prostate and breast epithelial cells. RNA-seq assays in C42B, prostate cancer cell line after knocking down of TFs (HOXC6, DLX1).
Project description:Fanconi anemia (FA) is a disorder of genomic instability characterized by progressive bone marrow failure (BMF), developmental abnormalities and an increased susceptibility to cancer. Although various consequences in hematopoietic stem/progenitor cells have been attributed to FA-BMF, the quest to identify the initial pathological event is still ongoing. To address this issue, we established induced pluripotent stem cells (iPSCs) from fibroblasts of six FA patients with FANCA mutations. An improved reprogramming method yielded iPSC-like colonies from all patients, and iPSC clones were propagated from two patients. Quantitative evaluation of the differentiation ability demonstrated that the differentiation propensity toward the hematopoietic and endothelial lineages is already defective in early hemoangiogenic progenitors. The expression levels of critical transcription factors were significantly downregulated in these progenitors. These data indicate that the hematopoietic consequences in FA patients originate from the early hematopoietic stage, and highlight the potential usefulness of iPSC technology for elucidating the pathogenesis of FA-BMF. The investigation of the RNA-seq analysis of iPSC-derived HAPCs.
Project description:Regulatory T cells (Tregs) play crucial role in maintenance of peripheral tolerance. Numerous clinical trials confirmed safety and efficacy of Treg treatment of for deleterious immune responses. However, Tregs lose their characteristic phenotype and suppressive potential during expansion ex vivo. In our experiment we demonstrate that mild hypothermia of 33C induces robust proliferation of human Tregs, preserves expression of FoxP3, CD25 and Helios, and prevents TSDR methylation during culture in vitro. Tregs expanded at 33C showed stronger immunosuppressive potential and anti-inflammatory phenotype. We show that a simple change in temperature can preserve Treg stability, function and accelerate their proliferation in vitro.
Project description:Cell cycle quiescence is a critical feature contributing to haematopoietic stem cell (HSC) maintenance. Although various candidate stromal cells have been identified as potential HSC niches, the spatial localization of quiescent HSC in the bone marrow (BM) remains unclear. Here, using a novel approach that combines whole-mount confocal immunofluorescence imaging technique and computational modelling to analyse significant tridimensional associations among vascular structures, stromal cells and HSCs, we show that quiescent HSCs associate specifically with small arterioles that are preferentially found in endosteal BM. These arterioles are ensheathed exclusively by rare Nestin-GFP-peri/NG2+ pericytes, distinct from sinusoid-associated Nestin-GFP-retic/LepR+ cells. The present RNA-seq study sought to obtain a comprehensive understanding of the differences between the two distinct HSC cellular niches. mRNA profiles of sorted Nestin-GFP-peri and -GFP-retic bone marrow stromal cells were generated from pooled mice in triplicate by Illumina HiSeq 2000 sequencing.
Project description:Systems biology is an approach to comprehensively study complex interactions within a biological system. Most published systems vaccinology studies have utilized whole blood or peripheral blood mononuclear cells (PBMC) to monitor the immune response after vaccination. Because human blood is comprised of multiple hematopoietic cell types, the potential for masking responses of under-represented cell populations is increased when analyzing whole blood or PBMC. To investigate the contribution of individual cell types to the immune response after vaccination, we established a rapid and efficient method to purify human T and B cells, natural killer (NK) cells, myeloid dendritic cells (mDC), monocytes, and neutrophils from fresh venous blood. Purified cells were fractionated and processed in a single day. RNA-Seq and quantitative shotgun proteomics were performed to determine expression profiles for each cell type prior to and after inactivated seasonal influenza vaccination. Our results show that transcriptomic and proteomic profiles generated from purified immune cells differ significantly from PBMC. Differential expression analysis for each immune cell type also shows unique transcriptomic and proteomic expression profiles as well as changing biological networks at early time points after vaccination. This cell type-specific information provides a more comprehensive approach to monitor vaccine responses. PBMC and six purified cell types from two vaccinated donors were isolated prior to (d0) and at days 1, 3, and 7 post-TIV vaccination for RNA-seq analysis