Background & Aims. Glycine N-methyltransferase (GNMT) is an essential regulator of the total transmethylation flux in the mammalian liver. Distinct DNA methylation patterns are characteristic of liver development, hepatic de-differentiation and liver disease progression, processes in which the levels of GNMT decrease dramatically by mechanisms still poorly understood. Interestingly, putative binding sites for the microRNA miRNA-873-5p were identified in the 3´UTR of GNMT suggesting a potential role for miRNA-873-5p in GNMT regulation. Results. We have identified that the hepatic expression of miRNA-873-5p was increased in a cohort of cirrhotic and liver cancer patients associated with a down-regulation of GNMT levels. Moreover, during liver development, hepatic de-differentiation and fibrosis, the elevation of miRNA-873-5p coincided with the reduction of GNMT expression, indicating that miRNA-873-5p specifically targets the expression of GNMT. Under these circumstances, inhibition of miRNA-873-5p induced GNMT levels and decreased global CpG methylation and transmethylation flux. Indeed, reestablishment of GNMT expression by miRNA-873-5p inhibition reduced hepatocyte de-differentiation, and abolished completely the mortality produced after bile duct ligation as a result of decreased proinflamatory and profibrogenic markers. miRNA-873-5p knockdown-mediated antifibrotic effect was significantly blunted if its effect on GNMT was blocked. Conclusion. Taken together, our studies highlight the role of miRNA-873-5p as a key regulator of GNMT expression, paving the way for new therapeutical approaches in liver de-differentiation and fibrosis. Overall design: Genome-wide changes in gene Expression in mouse livers from BDL treated or not with anti-miR-873 were generated by RNAseq.
MiR-873-5p acts as an epigenetic regulator in early stages of liver fibrosis and cirrhosis.
Age, Cell line, Treatment, Subject
View SamplesBackground and aims: Cholangiocarcinoma (CCA) is a heterogeneous group of malignancies with features of biliary tract differentiation. Incidence is increasing worldwide and these cancers collectively represent the second most common primary liver tumour. CCAs are characterized by genetic and epigenetic alterations that determine their pathogenesis. Hypermethylation of the SOX17 promoter was recently reported in human CCA tumours. SOX17 seems to be a key transcription factor for biliary embryogenesis. Here, we evaluated the role of SOX17 in cholangiocyte differentiation and in cholangiocarcinogenesis. Methods: SOX17 expression and function was evaluated during the differentiation of human induced pluripotent stem cells (iPSC) into cholangiocytes, in the dedifferentiation of normal human cholangiocytes (NHC) and in cholangiocarcinogenesis. Lentiviruses overexpressing or knocking-down SOX17 (Lent-SOX17 and Lent-shRNA-SOX17, respectively) were used. Gene expression arrays were performed. Results: SOX17 expression is highly induced in the later stages of cholangiocyte differentiation from iPSC, and mediates the acquisition of the biliary markers cytokeratin (CK) 7 and 19, as well as fibronectin. In addition, SOX17 becomes progressively downregulated in NHC over serial cell passages in vitro and this event is associated with cellular senescence; however, experimental SOX17 knocking-down in differentiated NHC decreased the expression of both CK7 and 19 without affecting cellular senescence. SOX17 expression is reduced in CCA cells compared to NHC, as well as in human CCA tissue compared to human gallbladder tissue or NHC. In a murine xenograft model, overexpression of SOX17 in CCA cells decreased their tumorigenic capacity related to increased oxidative stress and apoptosis. Interestingly, overexpression of SOX17 in NHC did not affect their survival. Moreover, SOX17 overexpression inhibited the Wnt/-catenin-dependent proliferation in CCA cells and was associated with upregulation of biliary epithelial markers and restoration of the primary cilium length. Both Wnt3a and TGF1 decreased SOX17 expression in NHC in a DNMT1-dependent manner. Inhibition of DNMT1 in CCA cells with siRNAs or pharmacological drugs upregulated SOX17 expression. Conclusion: SOX17 regulates the cholangiocyte phenotype and becomes epigenetically downregulated in CCA. SOX17 acts as a tumour suppressor in CCA, and restoration of its expression may have important therapeutic value.
SOX17 regulates cholangiocyte differentiation and acts as a tumor suppressor in cholangiocarcinoma.
Specimen part, Treatment
View SamplesEndogenous retroviruses (ERVs) have provided an evolutionary advantage in the diversification of transcript regulation and are thought to be involved in the establishment of extraembryonic tissues during development. However, silencing of these elements remains critical for the maintenance of genome stability. Here, we define a new chromatin state that is uniquely characterized by the combination of the histone variant H3.3 and H3K9me3, two chromatin ‘marks’ that have previously been considered to belong to fundamentally opposing chromatin states. H3.3/H3K9me3 heterochromatin is fundamentally distinct from ‘canonical’ H3K9me3 heterochromatin that has been under study for decades and this unique functional interplay of a histone variant and a repressive histone mark is crucial for silencing ERVs in ESCs. Our study solidifies the emerging notion that H3.3 is not a histone variant associated exclusively with “active” chromatin and further suggests that its incorporation at unique heterochromatic regions may be central to its function during development and the maintenance of genome stability. Overall design: RNA-seq analysis of three embryonic stem cell lines WT, H3.3 KO1, and H3.3 KO2)
Histone H3.3 is required for endogenous retroviral element silencing in embryonic stem cells.
No sample metadata fields
View SamplesAcute myeloid leukemia (AML) continues to have the lowest survival rates of all leukemias. Therefore, new therapeutic strategies are urgently needed to improve clinical outcomes for AML patients. Here, we report a novel role for Wilms’ tumor 1-associated protein (WTAP) in pathogenesis of AML. We have performed RNA-Seq in K562 cells with knockdown of WTAP to ascertain which genes it regulates. Overall design: We have 2 replicates of total RNA for K562 cells and 2 replicates with WTAP knocked down
WTAP is a novel oncogenic protein in acute myeloid leukemia.
Subject
View SamplesH3.3 phosphorylation promotes high levels of histone acetylation in mouse embryonic stem cells, which are central to the initiation of new transcription during lineage specification. Overall design: RNA-Seq analysis in mouse embryonic stem cells (Control, H3.3KO, HIRAKO, ATRXKO, DAXXKO) and embryoid bodies at Day 4 of differentiation (Control and H3.3KO).
Phosphorylation of histone H3.3 at serine 31 promotes p300 activity and enhancer acetylation.
Specimen part, Cell line, Subject
View SamplesPurpose: Recurrent ASXL1 mutations are frequently observed in all spectrums of myeloid malignancies and published data suggests that ASXL1 mutations may be involved in leukemic transformation as a tumor suppressor. Yet the molecular mechanisms of cell desitiny regulated by ASXL1 are to be further delineated. Methods: mRNA profiles of wild-type (WT) and CRISPR/Cas9 induced ASXL1 mutated U937 cell lines were generated by next generation sequencing, using Illumina HiSeq2500. Sequence reads were trimmed to remove possible adapter sequences and nucleotides with poor quality at the ends. Remaining sequence reads were then aligned to the human reference genome (hg19) using Tophat2. Gene read counts were measured using FeatureCounts and FPKM values were calculated with cufflinks. edgeR was used to identify differentially expressed genes between conditions, and topGO was used for annotation (Alexa, Rahnenfuhrer, and Lengauer, 2006). Sample comparison for differential gene expression was as follows: WTblk and WT1 versus MT2, MT3, MT4, and MT5. Gene enrichment set analysis (GSEA) was conducted with KEGG, Biocarta, and Reactome pathway datasets (Subramanian et al., 2005). Results: ASXL1-mutated cells displayed impaired differentiation capacity. RNA-seq was used to compare transcriptomes of ASXL1-mutated and WT U937 cells. Transcriptom analysis revealed that ASXL1 mutations decreased the expression of genes essential to myeloid differentiation, including CYBB and CLEC5A genes, which manifested in ASXL1-MT U937 cells as perturbed potential of differentiation compared with WT cells. Also, gene set enrichment analysis revealed that ASXL1 mutations masively affected gene sets relating to cell death and survival. Conclusion: By introduction of mutations into genome using the CRISPR/Cas9 system, we established ASXL1-mutated U937 cell lines. Our results indicated that ASXL1 mutations perturbed monocytic/phagocyte differentiation, which is a hallmark of myeloid malignancies, by down regulating genes essential to myeloid differentiation, including CYBB and CLEC5A, also massively affected multiple gene sets involving in cell survival. Overall design: mRNA profiles of wild type (WT) and ASXL1 mutated U937 cell lines were generated by deep sequencing using Illumina HiSeq2500
CRISPR/Cas9-mediated ASXL1 mutations in U937 cells disrupt myeloid differentiation.
Specimen part, Cell line, Subject
View SamplesMature oocyte cytoplasm can reprogram somatic cell nuclei to the pluripotent state through a series of sequential events including protein exchange between the donor nucleus and ooplasm, chromatin remodeling, and pluripotency gene reactivation. Maternal factors that are responsible for this reprogramming process remain largely unidentified. Here, we demonstrate that knockdown of histone variant H3.3 in mouse oocytes results in compromised reprogramming and down-regulation of key pluripotency genes; and this compromised reprogramming both for developmental potentials and transcription of pluripotency genes can be rescued by injecting exogenous H3.3 mRNA, but not H3.2 mRNA into oocytes in somatic cell nuclear transfer (SCNT) embryos. We show that maternal H3.3, and not H3.3 in the donor nucleus, is essential for successful reprogramming of somatic cell nucleus into the pluripotent state. Furthermore, H3.3 is involved in this reprogramming process by remodeling the donor nuclear chromatin through replacement of donor nucleus-derived H3 with de novo synthesized maternal H3.3 protein. Our study shows that H3.3 is a crucial maternal factor for oocyte reprogramming and provides a practical model to directly dissect the oocyte for its reprogramming capacity. Overall design: Transcriptome sequencing of 4-cell NT embryos, Luciferase 4-cell SCNT embryos, 4-cell NT embryos_H3.3KD, 4-cell NT embryos_H3.3KD+H3.3mRNA, H3.3 KD + H3.2 mRNA SCNT embryos
Histone variant H3.3 is an essential maternal factor for oocyte reprogramming.
No sample metadata fields
View Samplesto investigate the RA regulated genes in 2 dpp thy1+ gonocytes
Expression of stimulated by retinoic acid gene 8 (Stra8) and maturation of murine gonocytes and spermatogonia induced by retinoic acid in vitro.
No sample metadata fields
View SamplesPurpose: DNA methyltransferase 3A (DNMT3A) mediates de novo DNA methylation. Mutations in DNMT3A are associated with hematological malignancies, most frequently acute myeloid leukemia. DNMT3A mutations are hypothesized to establish a pre-leukemic state, rendering cells vulnerable to secondary oncogenic mutations and malignant transformation. However, the mechanisms by which DNMT3A mutations contribute to leukemogenesis are not well-defined. Methods: mRNA profiles of wild-type (WT) and DNMT3A mutated k562 cell lines were generated by deep sequencing, using Illumina HiSeq2500. Sequence reads were trimmed to remove possible adapter sequences and nucleotides with poor quality at the ends. Remaining sequence reads were then aligned to the human reference genome (hg19) using Tophat2. Gene read counts were measured using FeatureCounts and FPKM values were calculated with cufflinks. edgeR was used to identify differentially expressed genes between conditions, and topGO was used for annotation (Alexa, Rahnenfuhrer, and Lengauer, 2006). Sample comparison for differential gene expression was as follows: WTblk and WT1 versus MT2, MT3, MT4, and MT5. Gene enrichment set analysis (GSEA) was conducted with KEGG, Biocarta, and Reactome pathway datasets (Subramanian et al., 2005). Results: DNMT3A-mutated cells displayed impaired differentiation capacity. RNA-seq was used to compare transcriptomes of DNMT3A-mutated and WT cells; DNMT3A ablation resulted in downregulation of genes involved in spliceosome function, causing dysfunction of RNA splicing. Unexpectedly, we observed DNMT3A-mutated cells to exhibit marked genomic instability and an impaired DNA damage response compared to WT. Conclusions: CRISPR/Cas9-mediated DNMT3A-mutated K562 cells may be used to model effects of DNMT3A mutations in human cells. Our findings implicate aberrant splicing and induction of genomic instability as potential mechanisms by which DNMT3A mutations might predispose to malignancy. Overall design: mRNA profiles of wild type (WT) and DNMT3A mutated K562 cell lines were generated by deep sequencing using Illumina HiSeq2500
Abnormal RNA splicing and genomic instability after induction of DNMT3A mutations by CRISPR/Cas9 gene editing.
Specimen part, Cell line, Subject
View SamplesPolycomb repressive complex 2 (PRC2) regulates gene expression during lineage specification through trimethylation of lysine 27 on histone H3 (H3K27me3). In Drosophila, polycomb binding sites are dynamic chromatin regions coupled to incorporation of the histone variant H3.3. Here we show in mouse embryonic stem cells (ESCs) that H3.3 is required for proper establishment of H3K27me3 at the promoters of developmentally regulated genes. These promoters show reduced dynamics as determined by deposition of de novo synthesized histones, associated with reduced PRC2 occupancy. H3.3-depleted ESCs show upregulation of extraembryonic trophectoderm, as well as misregulation of other developmental genes upon differentiation. Our data demonstrate the importance of H3.3 incorporation in ESCs and suggest that changes in chromatin dynamics in its absence lead to misregulation of gene expression during differentiation. Moreover, our findings lend support to the emerging notion that H3.3 has multiple functions in distinct genomic locations that are not always correlated with an “active” chromatin state. Overall design: RNA-seq analysis of three embryonic stem cell lines (control, H3.3 KD1, and H3.3 KD2)
Hira-dependent histone H3.3 deposition facilitates PRC2 recruitment at developmental loci in ES cells.
Specimen part, Cell line, Subject
View Samples