Acute myeloid leukemia requires Hhex to enable PRC2-mediated epigenetic repression of Cdkn2a (ChIP-Seq)
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE74017 | GEO | 2016/10/18
SECONDARY ACCESSION(S): PRJNA298747
REPOSITORIES: GEO
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Project description:Unlike clustered HOX genes, the role of non-clustered homeobox gene family members in hematopoiesis and leukemogenesis has not been extensively studied. Here we find that the Hematopoietically-expressed Homeobox gene, Hhex, is overexpressed in acute myeloid leukemia (AML) and is essential for the initiation and propagation of MLL-ENL induced AML, but dispensable for normal myelopoiesis, indicating a specific requirement for Hhex for leukemic growth. Loss of Hhex leads to upregulated expression of the tumor suppressors p16INK4a and p19ARF, which are required for growth arrest and myeloid differentiation following Hhex deletion. Mechanistically, we show that Hhex binds to the Cdkn2a locus and is required for H3K27Me3-mediated repression of this locus. Thus, Hhex is a novel therapeutic target that is specifically required for AML stem cells to repress tumor suppressor pathways and enable continued self-renewal.
2016-10-18 | GSE74018 | GEO
Project description:The Hematopoietically-expressed homeobox (Hhex) transcription factor is overexpressed in human myeloid leukemias. Conditional knockout models of murine acute myeloid leukemia (AML) indicate that Hhex maintains leukemia stem cell self-renewal by enabling Polycomb-mediated epigenetic repression of the Cdkn2a tumor suppressor locus, encoding p16Ink4a and p19Arf. However, whether Hhex overexpression also affects hematopoietic differentiation is unknown. To study this, we retrovirally overexpressed Hhex in hematopoietic progenitors. This enabled serial replating of myeloid progenitors, leading to the rapid establishment of IL-3-dependent promyelocytic cell lines. Use of a Hhex-ERT2 fusion protein demonstrated that continuous nuclear Hhex is required for transformation, and structure function analysis demonstrated a requirement of the DNA binding and N-terminal repressive domains of Hhex for promyelocytic transformation. This included the N-terminal Pml interaction domain, although deletion of Pml failed to prevent Hhex-induced promyelocyte transformation, implying other critical partners. Furthermore, deletion of p16Ink4a or p19Arf did not promote promyelocyte transformation, indicating that repression of distinct Hhex target genes is required for this process. Indeed, transcriptome analysis showed that Hhex overexpression resulted in repression of several myeloid developmental genes. To test potential for Hhex overexpression to contribute to leukemic transformation, Hhex-transformed promyelocyte lines were rendered growth factor-independent using a constitutively active IL-3 receptor common b subunit (bcV449E). The resultant cell lines resulted in a rapid promyelocytic leukemia in vivo. Thus Hhex overexpression can contribute to myeloid leukemia via multiple mechanisms including differentiation blockade and enabling epigenetic repression of the Cdkn2a locus.
2018-01-30 | GSE109793 | GEO
Project description:The Hematopoietically-expressed homeobox transcription factor (Hhex) is important for the maturation of definitive hematopoietic progenitors and B-cells during development. We have recently shown that in adult hematopoiesis, Hhex is dispensable for maintenance of hematopoietic stem cells (HSCs) and myeloid lineages but essential for the commitment of Common Lymphoid Progenitors (CLPs) to lymphoid lineages. However, whether Hhex plays a role in HSC self-renewal and myeloid expansion during hematopoietic stress is unknown. Here we show that during serial bone marrow transplantation, Hhex-deleted HSCs are progressively lost, revealing an intrinsic defect in HSC self-renewal. Moreover, Hhex-deleted mice show markedly impaired hematopoietic recovery following myeloablation. In vitro, Hhex-null blast colonies were incapable of replating, implying a specific requirement for Hhex in immature hematopoietic progenitors. Transcriptome analysis of Hhex-null Lin-Sca+Kit+ (LSK) cells showed that Hhex deletion leads to the deregulation of Polycomb Repressive Complex 2 (PRC2) target genes, including an upregulation of Cdkn2a locus, encoding the cell cycle repressors p16Ink4a and p19Arf. Indeed, loss of Cdkn2a restored Hhex-null blast colony replating in vitro, as well as hematopoietic reconstitution following myeloablation in vivo. Thus, HSCs require Hhex to repress Cdkn2a to enable continued self-renewal and response to hematopoietic stress.
2017-05-22 | GSE86209 | GEO
Project description:Background & Aims: Perturbations in pancreatic ductal bicarbonate secretion often result in chronic pancreatitis. Although the physiological mechanism of ductal secretion is known, its transcriptional control is not well characterized. Here, we investigate the role of the transcription factor Hematopoietically-expressed homeobox protein (Hhex) in pancreatic secretion and pancreatitis. Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histological and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells (PDCs) were isolated to discover differentially expressed transcripts upon acute Hhex ablation. Results: Hhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia did not result from perturbations in primary cilia, but was consistent with the effects of primary ductal hypertension. RNA-seq analysis of Hhex-ablated PDCs indicated the G-protein coupled receptor Natriuretic peptide receptor 3, implicated in paracrine signaling, was upregulated 4.70-fold. Conclusions: Although Hhex is dispensable for adult pancreatic function, ablation of Hhex in pancreatic progenitors results in profound pancreatitis that is consistent with primary ductal hypertension. Our data highlight the critical role of paracrine signaling in maintaining ductal homeostasis, especially in early life, and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis. Pancreatic primary ductal cells (PDCs) were isolated from uninduced adult HhexL/L;Sox9CreERT2 (n=2) and littermate control HhexL/L (n=2) mice. PDCs were treated with 500nM 4-hydroxytamoxifen in vitro for 4 days, and then RNA was collected for transcriptome analysis.
2015-11-20 | E-GEOD-63526 | biostudies-arrayexpress
Project description:Memory B cells (MBCs) are essential for long-lived humoral immunity. However, the transcription factors (TFs) involved in MBC differentiation are poorly defined. Here, by single cell RNAseq analysis, we identified a population of germinal center (GC) B cells in the process of differentiating into MBCs. Using an inducible Crispr/Cas9 screening approach we identified the hematopoietically-expressed homeobox gene Hhex as a transcription factor regulating MBC differentiation. The co-repressor Tle3 was also identified in the screen and was found to interact with Hhex to promote MBC development. Bcl6 directly repressed Hhex in GC B cells. Reciprocally, Hhex-deficient MBCs exhibited derepressed Bcl6 and reduced expression of Bcl6-repressed Bcl2. Overexpression of Bcl2 was able to rescue MBC differentiation in Hhex-deficient cells. We also identified Ski as an Hhex-induced transcription factor involved in MBC differentiation. These findings establish an important role for Hhex-Tle3 in regulating the transcriptional circuitry governing MBC differentiation.
2020-06-29 | GSE148805 | GEO
Project description:Hhex encodes a homeobox transcriptional regulator that plays a key role in embryonic development and hematopoiesis. Hhex is highly expressed in NK cells and germline deletion of Hhex results in significant defects in lymphoid development, including NK cells. However, whether Hhex is intrinsically required throughout NK cell development or for NK cell function remains unknown. To investigate this, we generated mice that specifically lack Hhex in NK cells. Hhex was intrinsically required for NK cell homeostasis, while NK cell differentiation, IL-15 responsiveness and cytotoxic function were largely normal in the absence of Hhex. Unexpectedly, increased IL-15 availability failed to rescue Hhex-deficient NK cell homeostasis, suggesting that Hhex regulates developmental pathways extrinsic to those dependent on IL-15. Gene expression and functional genetic approaches revealed that Hhex promoted NK cell survival by repressing BIM expression, a key apoptotic mediator in NK cells. This study identifies Hhex as a novel transcription factor essential for NK cell biology.
2020-11-12 | GSE140284 | GEO
Project description:Background & Aims: Perturbations in pancreatic ductal bicarbonate secretion often result in chronic pancreatitis. Although the physiological mechanism of ductal secretion is known, its transcriptional control is not well characterized. Here, we investigate the role of the transcription factor Hematopoietically-expressed homeobox protein (Hhex) in pancreatic secretion and pancreatitis. Methods: We derived mice with pancreas-specific, Cre-mediated Hhex gene ablation to determine the requirement of Hhex in the pancreatic duct in early life and in adult stages. Histological and immunostaining analyses were used to detect the presence of pathology. Pancreatic primary ductal cells (PDCs) were isolated to discover differentially expressed transcripts upon acute Hhex ablation. Results: Hhex protein was detected throughout the embryonic and adult ductal trees. Ablation of Hhex in pancreatic progenitors resulted in postnatal ductal ectasia associated with acinar-to-ductal metaplasia, a progressive phenotype that ultimately resulted in chronic pancreatitis. Hhex ablation in adult mice, however, did not cause any detectable pathology. Ductal ectasia did not result from perturbations in primary cilia, but was consistent with the effects of primary ductal hypertension. RNA-seq analysis of Hhex-ablated PDCs indicated the G-protein coupled receptor Natriuretic peptide receptor 3, implicated in paracrine signaling, was upregulated 4.70-fold. Conclusions: Although Hhex is dispensable for adult pancreatic function, ablation of Hhex in pancreatic progenitors results in profound pancreatitis that is consistent with primary ductal hypertension. Our data highlight the critical role of paracrine signaling in maintaining ductal homeostasis, especially in early life, and support ductal hypersecretion as a novel etiology of pediatric chronic pancreatitis.
2015-11-20 | GSE63526 | GEO
Project description:Hhex encodes a homeobox transcriptional regulator important for embryonic development and hematopoiesis. Hhex is highly expressed in NK cells and its germline deletion results in significant defects in lymphoid development, including NK cells. To determine if Hhex is intrinsically required throughout NK cell development or for NK cell function, we generated mice that specifically lack Hhex in NK cells. NK cell numbers was dramatically reduced, while NK cell differentiation, IL-15 response and function at the cellular level remained largely normal in the absence of Hhex. Increased IL-15 availability failed to fully reverse NK lymphopenia following conditional Hhex deletion, suggesting that Hhex regulates developmental pathways extrinsic to those dependent on IL-15. Gene expression and functional genetic approaches revealed that Hhex regulates NK cell survival by repressing expression of the key apoptotic mediator, BIM. These data implicates Hhex as a novel transcription factor essential for NK cell homeostasis and immunity.
2020-08-11 | GSE155957 | GEO
Project description:Recently, we have reported a hematopoietic NKL-code which describes normal expression patterns of NKL homeobox genes in early hematopoiesis and lymphopoiesis including T-cell, B-cell and NK-cell development. This code allows the identification of deregulated NKL homeobox genes in lymphoid malignancies. Here, we report normal activities of NKL homeobox genes in myelopoiesis, thus, extending the NKL-code for the hematopoietic system. Analysis of public expression profiling data for developing and mature granulocytes, mast cells, monocytes, macrophages, megakaryocytes and erythrocytes revealed seven active myeloid NKL homeobox genes including DLX2, HHEX, HLX, HMX1, NANOG, NKX3-1 and VENTX. Furthermore, we analyzed public expression profiling data of 251 acute myeloid leukemia (AML) patients identifying 18 deregulated genes. These results indicated that NKL homeobox genes are frequently deregulated in this myeloid malignancy. For detailed analysis we focused on NKL homeobox gene NANOG which acts as stem cell factor and was accordingly expressed just in hematopoietic stem/progenitor cells. We detected aberrant NANOG expression in a small subset of AML patients and in AML cell line NOMO-1 which served as model to investigate upstream and downstream factors of this gene. Karyotyping and genomic profiling excluded rearrangements of the NANOG locus at 12p13. Analysis of NOMO-1 cells treated for NANOG knockdown, expression profiling analyses of HL-60 cells lentivirally transfected for NANOG overexpression, and of public AML patient data revealed regulators and target genes of NANOG. NKL homeobox genes HHEX and MSX1 and the NOTCH-pathway were located upstream of NANOG and HHEX, HLX, VENTX, MYB, CDK6, MAML2 and MIR17HG represented target genes of NANOG in the myeloid context. In conclusion, we described a myeloid NKL-code and several deregulated NKL homeobox genes in AML. We identified for NKL homeobox gene NANOG deregulating factors and downstream activities in AML. These data indicate a common oncogenic role of NKL homeobox genes in myeloid malignancies.
2020-05-31 | GSE131113 | GEO
Project description:We have cloned and characterized a fusion gene NUP98/HHEX1 resulting from t(7;10) from a patient with acute myeloid leukemia (AML). As NUP98/HHEX acts as an aberrant transcriptional activator, putative targets were searched upon transient expression of the fusion in primary murine bone marrow cells. Keywords: Comparative analysis of NUP98/HHEX, NUP98/HOX vs. MIG (empty virus) in primary bone marrow cells
2008-04-01 | GSE10909 | GEO