ASXL1 Mutations Promote Myeloid Transformation Through Loss of PRC2-Mediated Gene Repression
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE38861 | GEO | 2012/08/21
SECONDARY ACCESSION(S): PRJNA169078
REPOSITORIES: GEO
Similar Datasets
Project description:Recurrent somatic ASXL1 mutations occur in patients with myelodysplasia (MDS), myeloproliferative neoplasms (MPN), and acute myeloid leukemia (AML), and are associated with adverse outcome. Despite the genetic and clinical data implicating ASXL1 mutations in myeloid malignancies, the mechanisms of transformation by ASXL1 mutations are not understood. Here we identify that ASXL1 mutations result in loss of PRC2-mediated histone H3 lysine 27 (H3K27) tri-methylation. Through integration of microarray data with genome-wide histone modification ChIP-Seq data we identify targets of ASXL1 repression including the posterior HOXA cluster that is known to contribute to myeloid transformation. We demonstrate that ASXL1 associates with the Polycomb repressive complex 2 (PRC2), and that loss of ASXL1 in vivo collaborates with NRASG12D to promote myeloid leukemogenesis. To assess the genome-wide effects of ASXL1 loss on chromatin state we performed chromatin immunoprecipitation followed by next generation sequencing (CHIP-seq) for histone modifications known to be associated with PcG (histone H3 lysine 27 trimethylation (H3K27me3)) or TxG activity (histone H3 lysine 4 trimethylation (H3K4me3)) in UKE1 cells expressing empty vector (EV) or 2 independent validated shRNAs for ASXL1. This Series represents the ChIP-Seq data (not the microarray data referenced in the summary above). The related micorarray data are available in GEO as GSE38692.
2012-08-21 | E-GEOD-38861 | biostudies-arrayexpress
Project description:Recurrent mutations in ASXL1 are found in various hematological malignancies and are associated with poor prognosis. In particular, ASXL1 mutations are frequently found in patients with hematological malignancies associated with myelodysplasia including myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia. Although loss-of-function ASXL1 mutations promote myeloid transformation, a large subset of ASXL1 mutations is thought to result in stable truncation of ASXL1. Here we demonstrate that C-terminal truncating ASXL1 mutations (ASXL1-MT) inhibit myeloid differentiation and induce MDS-like disease in mice, displaying all the features of human MDS including multi-lineage myelodysplasia, pancytopenia and occasional progression to overt leukemia. Concerning the molecular mechanisms, ASXL1-MT derepressed expression of Hoxa9 and miR-125a through inhibiting PRC2-mediated methylation of H3K27. miR-125a targeted expression of a surface receptor Clec5a, which was found to supports for myeloid differentiation. In addition, HOXA9 expression was high in MDS patients with ASXL1 mutations while Clec5a expression was generally low in MDS patients. Thus, ASXL1-MT induced MDS-like disease in mice via derepression of Hoxa9 and miR-125a, and Clec5a downregulation. Our data provide evidence for a novel axis of MDS pathogenesis (ASXL1 mutations-upregulation of HoxA9 and miR-125a-downregulation of Clec5a) and implicate both ASXL1 mutants and miR-125a as therapeutic targets in MDS.
2013-07-31 | GSE49118 | GEO
Project description:Recurrent mutations in ASXL1 are found in various hematological malignancies and are associated with poor prognosis. In particular, ASXL1 mutations are frequently found in patients with hematological malignancies associated with myelodysplasia including myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia. Although loss-of-function ASXL1 mutations promote myeloid transformation, a large subset of ASXL1 mutations is thought to result in stable truncation of ASXL1. Here we demonstrate that C-terminal truncating ASXL1 mutations (ASXL1-MT) inhibit myeloid differentiation and induce MDS-like disease in mice, displaying all the features of human MDS including multi-lineage myelodysplasia, pancytopenia and occasional progression to overt leukemia. Concerning the molecular mechanisms, ASXL1-MT derepressed expression of Hoxa9 and miR-125a through inhibiting PRC2-mediated methylation of H3K27. miR-125a targeted expression of a surface receptor Clec5a, which was found to supports for myeloid differentiation. In addition, HOXA9 expression was high in MDS patients with ASXL1 mutations while Clec5a expression was generally low in MDS patients. Thus, ASXL1-MT induced MDS-like disease in mice via derepression of Hoxa9 and miR-125a, and Clec5a downregulation. Our data provide evidence for a novel axis of MDS pathogenesis (ASXL1 mutations-upregulation of HoxA9 and miR-125a-downregulation of Clec5a) and implicate both ASXL1 mutants and miR-125a as therapeutic targets in MDS.
2013-07-31 | GSE49117 | GEO
Project description:Recurrent mutations in ASXL1 are found in various hematological malignancies and are associated with poor prognosis. In particular, ASXL1 mutations are frequently found in patients with hematological malignancies associated with myelodysplasia including myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia. Although loss-of-function ASXL1 mutations promote myeloid transformation, a large subset of ASXL1 mutations is thought to result in stable truncation of ASXL1. Here we demonstrate that C-terminal truncating ASXL1 mutations (ASXL1-MT) inhibit myeloid differentiation and induce MDS-like disease in mice, displaying all the features of human MDS including multi-lineage myelodysplasia, pancytopenia and occasional progression to overt leukemia. Concerning the molecular mechanisms, ASXL1-MT derepressed expression of Hoxa9 and miR-125a through inhibiting PRC2-mediated methylation of H3K27. miR-125a targeted expression of a surface receptor Clec5a, which was found to supports for myeloid differentiation. In addition, HOXA9 expression was high in MDS patients with ASXL1 mutations while Clec5a expression was generally low in MDS patients. Thus, ASXL1-MT induced MDS-like disease in mice via derepression of Hoxa9 and miR-125a, and Clec5a downregulation. Our data provide evidence for a novel axis of MDS pathogenesis (ASXL1 mutations-upregulation of HoxA9 and miR-125a-downregulation of Clec5a) and implicate both ASXL1 mutants and miR-125a as therapeutic targets in MDS. BM cells derived from mock-transplanted mice and ASXL1-MT transplanted mice were incubated with biotinylated antibodies for CD3e, B220, and TER-119, followed by incubation with streptavidin Micro Beads (Miltenyi Biotec). The marker-negative fraction was separated with LS Columns (Miltenyi Biotec). Using the sorted-BM cells, we compared the expression proliles between 3 sorted-BM cells with mock and 3 sorted-BM cells with ASXL1-MT. Total RNA was extracted by Trizol reagent (Invitrogen) according to the manufacturer’s protocol. Double-stranded cDNA was synthesized from 5 μg of total RNA with oligo (dT)24 T7 primer, amplified with T7 RNA polymerase up to approximately 50 μg of cRNA, and hybridized to Affymetrix Mouse Expression array 430A, which contains 45000 probe sets for 39000 transcripts and variants from over 34000 well-characterized mouse genes (Affymetrix). After washing and staining, the arrays were scanned on the GeneChip system confocal scanner (Affymetrix). The intensity for each feature of the array was captured with Affymetrix Microarray Suite (MAS) Version 5.0 software. Gene set enrichment analysis was performed by using Gene Ontology gene sets from the Molecular Signatures Database (http://www.broad.mit.edu/gsea/msigdb/).
2013-07-31 | E-GEOD-49118 | biostudies-arrayexpress
Project description:Recurrent mutations in ASXL1 are found in various hematological malignancies and are associated with poor prognosis. In particular, ASXL1 mutations are frequently found in patients with hematological malignancies associated with myelodysplasia including myelodysplastic syndromes (MDS), and chronic myelomonocytic leukemia. Although loss-of-function ASXL1 mutations promote myeloid transformation, a large subset of ASXL1 mutations is thought to result in stable truncation of ASXL1. Here we demonstrate that C-terminal truncating ASXL1 mutations (ASXL1-MT) inhibit myeloid differentiation and induce MDS-like disease in mice, displaying all the features of human MDS including multi-lineage myelodysplasia, pancytopenia and occasional progression to overt leukemia. Concerning the molecular mechanisms, ASXL1-MT derepressed expression of Hoxa9 and miR-125a through inhibiting PRC2-mediated methylation of H3K27. miR-125a targeted expression of a surface receptor Clec5a, which was found to supports for myeloid differentiation. In addition, HOXA9 expression was high in MDS patients with ASXL1 mutations while Clec5a expression was generally low in MDS patients. Thus, ASXL1-MT induced MDS-like disease in mice via derepression of Hoxa9 and miR-125a, and Clec5a downregulation. Our data provide evidence for a novel axis of MDS pathogenesis (ASXL1 mutations-upregulation of HoxA9 and miR-125a-downregulation of Clec5a) and implicate both ASXL1 mutants and miR-125a as therapeutic targets in MDS. Using 32Dcl3 cells transduced with pMYs-IG (mock) and pMYs-FLAG-ASXL1-MT-IG, we compared the expression profiles of 32Dcl3 cells with mock or ASXL1-MT under G-CSF stimulation at 4 time points, including 0hr (IL-3), 2hr, 6hr and 24hrs. Total RNA was extracted by Trizol reagent (Invitrogen) according to the manufacturer’s protocol. Double-stranded cDNA was synthesized from 5 μg of total RNA with oligo (dT)24 T7 primer, amplified with T7 RNA polymerase up to approximately 50 μg of cRNA, and hybridized to Affymetrix Mouse Expression array 430A, which contains 45000 probe sets for 39000 transcripts and variants from over 34000 well-characterized mouse genes (Affymetrix). After washing and staining, the arrays were scanned on the GeneChip system confocal scanner (Affymetrix). The intensity for each feature of the array was captured with Affymetrix Microarray Suite (MAS) Version 5.0 software. Gene set enrichment analysis was performed by using Gene Ontology gene sets from the Molecular Signatures Database (http://www.broad.mit.edu/gsea/msigdb/)
2013-07-31 | E-GEOD-49117 | biostudies-arrayexpress
Project description:Additional Sex Combs Like 1 (ASXL1) is frequently mutated in myeloid malignancies and clonal hematopoiesis of indeterminate potential (CHIP). Although loss of ASXL1 promotes hematopoietic transformation, there is growing evidence that ASXL1 mutations might confer an alteration of function. Here we identify that physiological expression of a C-terminal truncated Asxl1 mutant in vivo using conditional knock-in (KI) results in myeloid skewing, age-dependent anemia, thrombocytosis, and morphologic dysplasia. Although expression of mutant Asxl1 altered the functions of hematopoietic stem cells (HSCs), it maintained their survival in competitive transplantation assays and increased susceptibility to leukemic transformation by co-occurring RUNX1 mutation or viral insertional mutagenesis. KI mice displayed substantial reductions in H3K4me3 and H2AK119Ub without significant reductions in H3K27me3, distinct from the effects of Asxl1 loss. ChIP-seq analysis demonstrated opposing effects of wildtype and mutant Asxl1 on H3K4me3. These findings reveal that ASXL1 mutations confer HSCs with an altered epigenome and increase susceptibility for leukemic transformation, presenting a novel model for CHIP.
2018-02-28 | GSE111067 | GEO
Project description:Oncogenic NRAS mutations are frequently identified in human myeloid leukemias. In mice, expression of endogenous oncogenic Nras (NrasG12D/+) in hematopoietic cells leads to expansion of myeloid progenitors, increased long-term reconstitution of bone marrow cells, and a chronic myeloproliferative neoplasm (MPN). However, acute expression of NrasG12D/+ in a pure C57BL/6 background does not induce hyperactivated GM-CSF signaling or increased proliferation in myeloid progenitors. It is thus unclear how NrasG12D/+ signaling promotes leukemogenesis. Here we show that hematopoietic stem cells (HSCs) expressing NrasG12D/+ serve as MPN initiating cells. They undergo moderate hyperproliferation with increased self-renewal. The aberrant NrasG12D/+ HSC function is associated with hyperactivation of ERK1/2 in HSCs. Conversely, downregulation of MEK/ERK by pharmacological and genetic approaches attenuates the cycling of NrasG12D/+ HSCs and prevents the expansion of NrasG12D/+ HSCs and myeloid progenitors. Our data delineate critical mechanisms of oncogenic Nras signaling in HSC function and leukemogenesis. three NrasG12D/G12D HSCs samples, three NrasG12D/+ HSCs samples, two Nras+/+ HSCs control samples.
2013-05-29 | E-GEOD-46948 | biostudies-arrayexpress
Project description:ASXL1 is the obligate regulatory subunit of a deubiquitinase complex whose catalytic subunit is BAP1. Heterozygous mutations of ASXL1 that result in premature truncations are frequent in myeloid leukemias and Bohring-Opitz syndrome. Here, we demonstrate that truncated ASXL1 proteins confer enhanced activity on the ASXL1-BAP1 complex. Stable expression of truncated, hyperactive ASXL1-BAP1 complexes in a hematopoietic precursor cell line resulted in global erasure of H2AK119Ub, striking depletion of H3K27me3, selective upregulation of a subset of genes whose promoters bore both H2AK119Ub and H3K4me3, and spontaneous differentiation to the mast cell lineage. These outcomes required the catalytic activity of BAP1, indicating these events were downstream consequences of H2AK119Ub erasure. In bone marrow precursors, truncated ASXL1-BAP1 expression cooperated with TET2 loss-of-function to increase differentiation to the myeloid lineage in vivo. We propose that pathological ASXL1 mutations confer gain-of-function on the ASXL-BAP1 complex. ChIP-Seq for H2AK119Ub, H3K4me3, H3K27me3 on EML cells. RNA-Seq on EML cells expressing ASXL1(1-479)+BAP1 and control.
2015-03-11 | E-GEOD-65555 | biostudies-arrayexpress
Project description:Purpose: 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.
2018-03-14 | GSE98104 | GEO
Project description:ASXL1 gene is one of the most frequently mutated genes in malignant myeloid diseases. In patients, ASXL1 mutations are usually heterozygous frameshift or non-sense mutations leading to C-terminal truncation. Here, we generated an endogenous C-terminal truncated Asxl1 mutant in zebrafish which is more comparable to human malignant leukemia patients. Our data showed that at embryonic stage, neutrophil differentiation was explicitly blocked in our mutant. To understand the basis for the impairment of neutrophil differentiation in zebrafish asxl1 mutants, we performed RNA-seq of asxl1 mutants at 3dpf and their littermate controls. Similar with the phenotype we observed, the expression of neutrophil markers were all included in down-regulated genes. Nonetheless, the expression of myeloid progenitor marker and macrophage marker were not impaired in asxl1 mutants. We also found inflammatory cytokine and matrix metalloproteinases were upregulated after mutated asxl1. It suggests that neutrophil deficiency may stimulate the expression of some inflammatory cytokines and enhances the inflammatory responds. Therefore, transcriptome analysis mainly represented the disruption of neutrophil development.
2021-08-04 | GSE142214 | GEO