A Master Cistromic Circuit Governing Hepatic Fibrogenesis
Ontology highlight
ABSTRACT:
ORGANISM(S): Rattus norvegicus
SUBMITTER: Ruth Yu
PROVIDER: E-GEOD-41580 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
Publications
A vitamin D receptor/SMAD genomic circuit gates hepatic fibrotic response.
Ding Ning N Yu Ruth T RT Subramaniam Nanthakumar N Sherman Mara H MH Wilson Caroline C Rao Renuka R Leblanc Mathias M Coulter Sally S He Mingxiao M Scott Christopher C Lau Sue L SL Atkins Annette R AR Barish Grant D GD Gunton Jenny E JE Liddle Christopher C Downes Michael M Evans Ronald M RM
Cell 20130401 3
Liver fibrosis is a reversible wound-healing response involving TGFβ1/SMAD activation of hepatic stellate cells (HSCs). It results from excessive deposition of extracellular matrix components and can lead to impairment of liver function. Here, we show that vitamin D receptor (VDR) ligands inhibit HSC activation by TGFβ1 and abrogate liver fibrosis, whereas Vdr knockout mice spontaneously develop hepatic fibrosis. Mechanistically, we show that TGFβ1 signaling causes a redistribution of genome-wid ...[more]
Similar Datasets
Project description:Liver fibrosis is a reversible wound-healing response to liver injury and hepatic stellate cells (HSCs) are central cellular players that mediate hepatic fibrogenesis. However, the molecular mechanisms that govern this process remain unclear. Here, we reveal a novel cistromic circuit in HSCs comprising the vitamin D receptor (VDR) and SMAD transcription factors that restrains the intensity of hepatic fibrogenesis. Ligand-activated VDR suppresses TGFβ1-induced pro-fibrotic gene expression in HSCs. Administration of a vitamin D analogue, calcipotriol, diminishes the fibrotic response in a mouse model of liver fibrosis, while VDR knockout mice spontaneous develop extensive hepatic fibrosis by age 6 months. Using ChIP-Seq, we find that the anti-fibrotic properties of VDR are due to crosstalk with SMAD, mediated by their co-occupancy of DNA-binding sites on pro-fibrotic genes. Specifically, SMAD binding potentiates local chromatin accessibility to enhance VDR recruitment at the same cis-regulatory elements, which reciprocally antagonizes the interaction between SMAD3 and chromatin and limits the assembly of transcriptional activation complexes at fibrotic genes, a process that is enhanced by the presence of VDR agonists. These results not only establish this coordinated VDR/SMAD cistromic circuit as a master regulator of hepatic fibrogenesis, but also support VDR as a potential drug target to ameliorate liver fibrosis. Identification of VDR, SMAD3 and H3 binding sites in human stellate LX2 cells that were pre-treated with calcipotriol (100nM) for 16 hrs (where calcipotriol treatment is indicated) followed by incubation of calcipotriol (100nM) or TGFβ1 (1ng/ml) for another 4 hours (where indicated).
2013-04-29 | E-GEOD-38103 | biostudies-arrayexpress
Project description:Here, we investigate the role of enhancers in myofibroblasts, a cell type that dominates the pathogenesis and progression of tissue fibrosis. We reveal that bromodomain and extra-terminal family members (BETs), an important group of epigenetic readers, are critical for super-enhancer-mediated pro-fibrotic gene expression in hepatic stellate cells (HSCs, lipid-containing liver-specific pericytes), upon activation during liver fibrogenesis give rise to myofibroblasts2-4. We observe significantly enriched localization of BETs to hundreds of super-enhancers associated with genes involved in multiple pro-fibrotic pathways. This unique loading pattern consequentially serves as a molecular mechanism by which BETs modulate pro-fibrotic gene expression in myofibroblasts. Strikingly, suppression of BET-enhancer interaction using small-molecule inhibitors such as JQ1 dramatically blocks activation of HSCs into myofibroblasts and significantly compromises the proliferation of activated HSCs. Identification of BRD2, BRD3, BRD4, PolII, PolIIs2p and PolIIs5p binding sites in human stellate LX2 cells that were treated with DMSO (0.1%) or JQ1 (500nM) for 16 hrs.
2015-12-11 | E-GEOD-58680 | biostudies-arrayexpress
Project description:RUNX2 is a transcription factor that is first expressed in early osteoblast-lineage cells and represents a primary determinant of osteoblastogenesis. While numerous target genes are regulated by RUNX2, little is known of sites on the genome occupied by RUNX2 or of the gene networks that are controlled by these sites. To explore this, we conducted a genome-wide analysis of the RUNX2 cistrome in both pre-osteoblastic MC3T3-E1 cells (POB) and their mature osteoblast progeny (OB), characterized the two cistromes and assessed their relationship to changes in gene expression. We found that although RUNX2 was widely bound to the genome in POB cells, this binding profile was reduced upon differentiation to OBs. Numerous sites were lost upon differentiation, new sites were also gained; many sites remained common to both cell states. Additional features were identified as well including location relative to potential target genes, abundance with respect to single genes, the frequent presence of a consensus TGTGGT RUNX2 binding motif, co-occupancy by C/EBPβ and the presence of a typical epigenetic histone enhancer signature. This signature was changed quantitatively following differentiation. While RUNX2 binding sites were associated extensively with adjacent genes, the distal nature of the majority of these sites prevented assessment of whether they represented direct targets of RUNX2 action. Changes in gene expression, however, revealed an abundance of genes that contained RUNX2 binding sites and were regulated in concert. These studies establish a basis for further analysis of the role of RUNX2 activity and its function during osteoblast lineage maturation. RNA was isolated and applied to gene expression microarrays in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells. The samples were completed in biological triplicate.
2014-04-24 | E-GEOD-41954 | biostudies-arrayexpress
Project description:The biological effects of 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) on osteoblast differentiation and function differ significantly depending upon the cellular state of maturation. To explore this phenomenon mechanistically, we examined the impact of 1,25(OH)2D3 on the transcriptomes of both pre-osteoblastic (POBs) and differentiated osteoblastic (OBs) MC3T3-E1 cells, and assessed localization of the vitamin D receptor (VDR) at sites of action on a genome-scale using ChIP-seq analysis. We observed that the 1,25(OH)2D3-induced transcriptomes of POBs and OBs were quantitatively and qualitatively different, supporting not only the altered biology observed but the potential for a change in VDR interaction at the genome as well. This idea was confirmed through discovery that VDR cistromes in POBs and OBs were also strikingly different. Depletion of VDR binding sites in OBs, due in part to reduced VDR expression, was the likely cause of the loss of VDR-target gene interaction. Continued novel regulation by 1,25(OH)2D3, however, suggested that factors in addition to the VDR might also be involved. Accordingly, we show that transcriptomic modifications are also accompanied by changes in genome binding of the master osteoblast regulator RUNX2 and the chromatin remodeler C/EBPβ. Importantly, genome occupancy was also highlighted by the presence of epigenetic enhancer signatures which were selectively changed in response to both differentiation and 1,25(OH)2D3. The impact of VDR, RUNX2, and C/EBPβ on osteoblast differentiation is exemplified by their actions at the Runx2 and Sp7 gene loci. We conclude that each of these mechanisms may contribute to the diverse actions of 1,25(OH)2D3 on differentiating osteoblasts. RNA was isolated and applied to gene expression microarrays in undifferentiated MC3T3-E1 cells as well as post 15 day osteogenic differentiation MC3T3-E1 cells, which were treated for 24 hours with 10-7M 1,25(OH)2D3. For the vehicle matched samples, please refer to study GSE41955. The samples were completed in biological triplicate.
2014-06-02 | E-GEOD-51514 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-04-24 | E-GEOD-41955 | biostudies-arrayexpress
Project description:This SuperSeries is composed of the SubSeries listed below. Refer to individual Series
2014-06-02 | E-GEOD-51515 | biostudies-arrayexpress
Project description:Heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 plays a pivotal role in vitamin D receptor (VDR) signaling by acting as a vitamin D response element (VDRE)-binding protein (VDRE-BP). Transcriptional regulation by active 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) involves occupancy of VDRE by VDRE-BP or 1,25(OH)2D3 bound-VDR. This relationship is disrupted by over-expression of VDRE-BP and can cause a form of human hereditary vitamin D-resistant rickets (HVDRR). DNA array analyses using B-cells from an HVDRR patient and matched control defined a sub-cluster of genes where 1,25(OH)2D3-regulated transcription was abrogated by over-expression of VDRE-BP. Amongst these, the DNA-damage-inducible transcript 4 (DDIT4), an inhibitor of mammalian target of rapamycin (mTOR) signaling, was also induced by 1,25(OH)2D3 in human osteoblasts. Chromatin immunoprecipitation using 1,25(OH)2D3-treated osteoblasts confirmed that liganded VDR and VDRE-BP compete for binding to the proximal promoter of the DDIT4 gene in a similar fashion to other known 1,25(OH)2D3-target genes. Treatment of osteoblasts with 1,25(OH)2D3 induced DDIT4 expression and suppressed phosphorylated S6K1T389 protein (a downstream target of mTOR). The functional importance of this for 1,25(OH)2D3 responses in osteoblasts was underlined by the fact that siRNA knockdown of DDIT4 expression suppressed antiproliferative and cell growth responses to 1,25(OH)2D3. These data confirm that VDRE-BP is required for normal 1,25(OH)2D3-mediated transcription and cell function in osteoblasts. Conversely over-expression of VDRE-BP exerts a dominant-negative effect on transcription of 1,25(OH)2D3-target genes. Characterization of VDRE-BP action in 1,25(OH)2D3-treated osteoblasts highlights an entirely novel role for vitamin D as a regulator of mTOR – a known ‘master regulator’ of cell function. We performed gene expression microarray analysis in HVDRR EBV-transformed B-cells and control cells in the presence or absence of vitamin D.
2010-11-19 | E-GEOD-22523 | biostudies-arrayexpress
Project description:The negative feedback mechanism is essential to maintain effective immunity and tissue homeostasis. 1,25-dihydroxyvitamin D (1,25(OH)2D3) modulates innate immune response, but the mechanism remains poorly understood. Here we report that vitamin D receptor (VDR) signaling attenuates Toll-like receptor-mediated inflammation by enhancing the negative feedback inhibition. VDR inactivation leads to a hyperinflammatory response in mice and macrophage cultures when challenged with lipopolysaccharide (LPS) due to miR-155 overproduction that excessively suppresses SOCS1, a key regulator that enhances the negative feedback loop. Deletion of miR-155 attenuates vitamin D suppression of LPS-induced inflammation, confirming that 1,25(OH)2D3 stimulates SOCS1 by down-regulating miR-155. 1,25(OH)2D3 down-regulates bic transcription by inhibiting NF-kappaB activation, which is mediated by a kappaB cis-DNA element located within the first intron of the bic gene. Together these data identify a novel regulatory mechanism for vitamin D to control innate immunity. MicroRNA arrays. Total RNAs were extracted from RAW264.7 cells (mouse macrophage line) treated with LPS (100ng/ml) in the presence or absence of 1,25(OH)2D3 (20 nM) overnight. MicroRNA profiling was performed using the miRCURY LNA microRNA Arrays (Exiqon, Vedvaek,Denmark) according to the manufacture'¹s standard protocols. The arrays were scanned with the GenePix 4000B scanner using the manufacturer's recommended settings. The raw data was extracted using GenePix Pro and imported into GeneSpring GX10 for analyses.
2013-01-05 | E-GEOD-43300 | biostudies-arrayexpress
Project description:Vitamin D deficiency is associated with high risk of colon cancer and a variety of other diseases. The active vitamin D metabolite 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) regulates gene transcription via its nuclear receptor (VDR), and posttranscriptional regulatory mechanisms of gene expression have also been proposed. We have identified microRNA-22 (miR-22) and several other miRNA species as 1,25(OH)2D3 targets in human colon cancer cells. Remarkably, miR-22 is induced by 1,25(OH)2D3 in a time-, dose-, and VDR-dependent manner. In SW480-ADH and HCT116 cells, miR-22 loss-of-function by transfection of a miR-22 inhibitor (anti-miR-22) suppresses the effect of 1,25(OH)2D3. Additionally, miR-22 inhibition increases cell migration per se and decreases the antimigratory effect of 1,25(OH)2D3 in both cell types. In silico analysis shows a significant overlap between genes suppressed by 1,25(OH)2D3 and miR-22 putative target genes. Consistently, miR-22 inhibition abrogates the reduction by 1,25(OH)2D3–mediated suppression of NELL2, OGN, HNRPH1, and NFAT5 genes. In 39 out of 50 (78%) human colon cancer patients, miR-22 expression was found lower in the tumor than in the matched normal tissue and correlated directly with that of VDR. Our results indicate that miR-22 is induced by 1,25(OH)2D3 in human colon cancer cells and it may contribute to its antitumor action against this neoplasia. We have analysed a human colon cancer cell line, SW480-ADH, treated with 1,25(OH)2D3 or isopropanol (vehicle) at three different time points (24, 48 and 96 hours). Each experiment was replicated 2 times by dye swap.
2011-12-20 | E-GEOD-34564 | biostudies-arrayexpress
Project description:Vitamin D may have anti-tumorigenic actions by influencing the gene expression profile of target tissues, which possess vitamin D receptors. We used a more physiological in vitro model, represented by short-term culture of breast cancer tissue slices, to study the transcriptional effects of a near physiological concentration of calcitriol. Methods. Breast cancer fragments were sliced and maintained in culture for 24 hours in the presence or absence (control) of calcitriol 0.5nM or 100nM (called physiological or supra-physiological concentrations). Five and 16 samples were included in a test or validation group and gene expression was analyzed by microarray (using SAM paired analysis) or qPCR, respectively. Results. Nine genes were regulated by calcitriol 0.5nM including CYP24A1, DPP4, EFTUD1 (FDR£0.01), which were up-modulated. However, using a less stringent FDR value (0.25) 61 genes were differentially expressed. Among the down-regulated transcripts were members of the MHC class II complex (HLA-DPA1, HLA-DQA1, HLA-DQA2, HLA-DQB1, HLA-DRA, HLA-DRB1, HLA-DRB3) and IgG binding (FCGR2A, FCGR2B, FCGR2C). There was an enrichment of genes presenting transcription factor binding sites for vitamin D, among the up-regulated genes and for interferon regulatory factor IRF1, among the down-regulated genes. Analyzing calcitriol supra-physiological effects, a more impressive transcriptional modulation was identified and 136 and 60 genes (FDR 0.1) were more and less expressed in treated samples. Up-regulated genes were involved in vitamin metabolic process, regulation of leukocyte-mediated immunity and positive regulation of alpha-beta T cell activation. Many of the induced genes were already reported as vitamin D responsive genes, including CD14, which was also up-regulated in another set of 16 samples. Genes modulated by both calcitriol concentrations were CYP24A1, DPP4, CA2 (these three in both sets of samples), EFTUD1, TKTL1, KCNK3. Conclusion. Small increments in calcitriol concentration, within the physiological range, for a relatively short period of time may exert transcriptional effects in breast cancer samples. Further studies employing physiological concentrations of vitamin D for longer periods of time may help to elucidate the hormone effects in breast cancer treatment and prevention. Breast cancer fragments were sliced and maintained in culture for 24 hours in the presence or absence (control) of calcitriol 0.5nM or 100nM (called physiological or supra-physiological concentrations). Five samples were included and were categorized according to treatment in three groups: control (A), 1,25(OH)2D3 0.5nM (B) and 1,25(OH)2D3 100nM (C).Total RNA was isolated using RNeasy kit and than was carried out according to microarray Affymetrix protocol. Data was then assessed with GeneSpring X software for background correction, normalization and summarization of raw data (CEL files) using the Robust Multi-Array Average (RMA). Five samples were included in a test and gene expression was analyzed by microarray (using SAM paired analysis). To establish a differential gene expression profile between vitamin D treated and untreated samples, SAM two class paired, provided on MEV (MultiExperiment Viewer – Boston, MA, USA) was used. Unsupervised hierarchical clustering based on Euclidean distance and average linkage was used to verify association patterns. The reliability of the clustering was assessed by the Bootstrap technique using MEV (MultiExperiment Viewer – Boston, MA, USA). Samples (16) were included in a validation group and was analyzed by qPCR.
2011-02-11 | E-GEOD-27220 | biostudies-arrayexpress