Project description:Acute myeloid leukemia (AML) and acute T-lymphoblastic leukemia (T-ALL) maintain the undifferentiated phenotype and proliferative capacity of their respective cells of origin, hematopoietic stem/progenitor cells and immature thymocytes. The mechanisms that maintain these progenitor-like characteristics are poorly understood. We report that the transcription factor Zfx is required for the development and propagation of experimental AML caused by MLL-AF9 fusion, and of T-ALL caused by Notch1 activation. In both leukemia types, Zfx activated progenitor-associated gene expression programs and prevented differentiation. Key Zfx target genes included mitochondrial enzymes Ptpmt1 and Idh2, whose overexpression partially rescued the propagation of Zfx-deficient AML. These studies identify a common mechanism that controls the cell-of-origin characteristics of acute leukemias derived from disparate lineages and transformation mechanisms. Bone marrow progenitors (c-Kit +) from Zfx wt/y CreER mice and Zfx fl/y CreER mice were harvested after tamoxifen administration to induce Cre. The Zfx wt and Zfx ko progenitors were infected with Myc expressing and control retrovirus with GFP selectable marker and cultured for 48 hours in cytokine supplemented media. The GFP + myeloid progenitors were sorted and cultured for another 4 days prior to RNA extraction.
Project description:Collombet2016 - Lymphoid and myeloid cell
specification and transdifferentiation
This model is described in the article:
Logical modeling of lymphoid
and myeloid cell specification and transdifferentiation
Samuel Collombet, Chris van Oevelen,
Jose Luis Sardina Ortega, Wassim Abou-Jaoudé, Bruno Di
Stefano, Morgane Thomas-Chollier, Thomas Graf, and Denis
Thieffry
Proceedings of the National Academy of
Sciences of the United States of America
Abstract:
Blood cells are derived from a common set of hematopoietic
stem cells, which differentiate into more specific progenitors
of the myeloid and lymphoid lineages, ultimately leading to
differentiated cells. This developmental process is controlled
by a complex regulatory network involving cytokines and their
receptors, transcription factors, and chromatin remodelers.
Using public data and data from our own molecular genetic
experiments (quantitative PCR, Western blot, EMSA) or
genome-wide assays (RNA-sequencing, ChIP-sequencing), we have
assembled a comprehensive regulatory network encompassing the
main transcription factors and signaling components involved in
myeloid and lymphoid development. Focusing on B-cell and
macrophage development, we defined a qualitative dynamical
model recapitulating cytokine-induced differentiation of common
progenitors, the effect of various reported gene knockdowns,
and the reprogramming of pre-B cells into macrophages induced
by the ectopic expression of specific transcription factors.
The resulting network model can be used as a template for the
integration of new hematopoietic differentiation and
transdifferentiation data to foster our understanding of
lymphoid/myeloid cell-fate decisions.
This model is hosted on
BioModels Database
and identified by:
MODEL1610240000.
To cite BioModels Database, please use:
BioModels Database:
An enhanced, curated and annotated resource for published
quantitative kinetic models.
To the extent possible under law, all copyright and related or
neighbouring rights to this encoded model have been dedicated to
the public domain worldwide. Please refer to
CC0
Public Domain Dedication for more information.
Project description:Acute myeloid leukemia (AML) and acute T-lymphoblastic leukemia (T-ALL) maintain the undifferentiated phenotype and proliferative capacity of their respective cells of origin, hematopoietic stem/progenitor cells and immature thymocytes. The mechanisms that maintain these progenitor-like characteristics are poorly understood. We report that the transcription factor Zfx is required for the development and propagation of experimental AML caused by MLL-AF9 fusion, and of T-ALL caused by Notch1 activation. In both leukemia types, Zfx activated progenitor-associated gene expression programs and prevented differentiation. Key Zfx target genes included mitochondrial enzymes Ptpmt1 and Idh2, whose overexpression partially rescued the propagation of Zfx-deficient AML. These studies identify a common mechanism that controls the cell-of-origin characteristics of acute leukemias derived from disparate lineages and transformation mechanisms. Independent primary Notch induced T-ALL cell lines were created by retroviral transduction of Notch-IC into hematopoietic progenitors carrying the tamoxifen inducible Cre-ER transgene and the Zfx conditional (Zfx fl/y) allele (lines 14843, 14844, 14846). T-ALL cells generated from each line were isolated from moribund mice and transplanted into sublethally irradiated secondary recipients. Ten days after transplant when T-ALL cells had appeared in the blood of the secondary recipients, they were treated by gavage with either Vehicle or Tamoxifen (5 mg /day for three days) to induce Zfx deletion in leukemia cells. 48 hours after the final Tamoxifen treatment, the mice were sacrificed and T-ALL cells were recovered by FACS for microarray studies.
Project description:Stem cells (SC) exhibit a unique capacity for self-renewal in an undifferentiated state. It is unclear whether the self-renewal of pluripotent embryonic SC (ESC) and of tissue-specific adult SC such as hematopoietic SC (HSC) is controlled by common mechanisms. The deletion of transcription factor Zfx impaired the self-renewal but not the differentiation capacity of murine ESC; conversely, Zfx overexpression facilitated ESC self-renewal by opposing differentiation. Furthermore, Zfx deletion abolished the maintenance of adult bone marrow HSC, but did not affect erythromyeloid progenitors or fetal HSC. In both ESC and HSC, Zfx activated a common set of direct target genes. In addition, the loss of Zfx resulted in the induction of immediate-early and/or stress-inducible genes in both SC types but not in their differentiated progeny. These studies identify the first shared transcriptional regulator of ESC and HSC, suggesting a common molecular basis of self-renewal in embryonic and adult SC. Keywords: Global gene expression data analysis in Zfx-deficient murine ESC and HSC
Project description:The development, homeostasis and function of B lymphocytes involve multiple rounds of B cell receptor (BCR)-controlled proliferation and prolonged maintenance. We analyzed the role of transcription factor Zfx, a recently identified regulator of stem cell maintenance, in B cell development and homeostasis. Conditional Zfx deletion in the bone marrow blocked B cell development at the pre-BCR selection checkpoint. Zfx deficiency in peripheral B cells caused impaired generation of the B-1 cell lineage, accelerated B cell turnover, depletion of mature recirculating cells, and delayed T-dependent antibody responses. Zfx-deficient B cells showed normal proximal BCR signaling, but impaired BCR-induced proliferation and survival. This was accompanied by aberrantly enhanced and prolonged integrated stress response, and delayed induction of Cyclin D2 and Bcl-xL proteins. Thus, Zfx restrains the stress response and couples antigen receptor signaling to B cell expansion and maintenance during development and peripheral homeostasis. Keywords: Expression profiling by array
Project description:The ZFX transcriptional activator binds to CpG island promoters, with a major peak at ~200-250bp downstream from transcription start sites. Because ZFX binds within the transcribed region, we investigated whether it regulates transcriptional elongation. We used GRO-seq to show that loss or reduction of ZFX increased the pause ratio at ZFX-regulated promoters. To further investigate the mechanisms by which ZFX regulates transcription, we determined regions of the protein needed for transactivation and for recruitment to the chromatin. Interestingly, although ZFX has 13 grouped zinc fingers, deletion of the first 11 fingers produces a protein that can still bind to chromatin and activate transcription. We next used TurboID-MS to detect ZFX-interacting proteins, identifying ZNF593, proteins that interact with the N-terminal transactivation domain (e.g. histone modifying proteins), and proteins that interact with ZFX when it is bound to the chromatin (e.g. TAFs and other histone modifying proteins). Our studies support a model in which ZFX enhances elongation at target promoters by recruiting H4 acetylation complexes and reducing pausing.
Project description:Ubiquitination is a post-translational mechanism of control of diverse cellular processes. We focus here on the ubiquitin ligase Fbw7, a recently identified hematopoietic tumor suppressor that can target for degradation several important oncogenes including Notch1, c-Myc and cyclin E. We have generated conditional Fbw7 knock-out animals and inactivated the gene in hematopoietic stem cells (HSC) and their differentiated progeny. Deletion of Fbw7 specifically and rapidly affects the HSC compartment in a cell-autonomous manner. Fbw7-/- HSCs show defective maintenance of quiescence, leading to impaired self-renewal and a severe loss of competitive repopulating capacity. Furthermore, Fbw7-/- HSC are unable to colonize the thymus leading to a profound depletion of T cell progenitors. Deletion of Fbw7 in bone marrow stem cells and progenitors leads to the stabilization of c-Myc, a transcription factor previously implicated in HSC self-renewal. On the other hand, neither Notch1 nor cyclin E are stabilized in the bone marrow of Fbw7 deficient mice. Genome-wide transcriptome studies of Fbw7-/- HSC and hematopoietic progenitors indicate that Fbw7 controls, through the regulation of HSC cell cycle entry, the global transcriptional âsignatureâ that is associated with the quiescent, self-renewing HSC phenotype. Transcriptional consequences of inactivating Fbw7 in LKS cells. Experiment Overall Design: Four samples were analyzed: wild-type (WT) control and Fbw7-deficient (FBW7) Lin-ckit+Sca1+ (LSK) cells, as well as Lin-ckit+Sca1- myeloid progenitor (MP) cells, which served as a control for LSK-enriched/specific genes. Total bone marrow cells were pooled from three WT and three FBW7 mice before sorting LSK and MP populations.