Rescue of the lethal scl−/− phenotype by the human SCL locus

Blood ◽  
2002 ◽  
Vol 99 (11) ◽  
pp. 3931-3938 ◽  
Author(s):  
Angus M. Sinclair ◽  
Anthony J. Bench ◽  
Adrian J. C. Bloor ◽  
Juan Li ◽  
Berthold Göttgens ◽  
...  
Keyword(s):  
Yeast Artificial Chromosome ◽  
Fetal Liver ◽  
Critical Role ◽  
Artificial Chromosome ◽  
Regulatory Elements ◽  
Yolk Sac ◽  
Loss Of Function ◽  
Hematopoietic Stem ◽  
Helix Loop Helix

The stem cell leukemia (SCL) gene encodes a basic helix-loop-helix transcription factor with a critical role in the development of both blood and endothelium. Loss-of-function studies have shown that SCL is essential for the formation of hematopoietic stem cells, for subsequent erythroid development and for yolk sac angiogenesis. SCL exhibits a highly conserved pattern of expression from mammals to teleost fish. Several murine SCLenhancers have been identified, each of which directs reporter gene expression in vivo to a subdomain of the normal SCL expression pattern. However, regulatory elements necessary for SCL expression in erythroid cells remain to be identified and the size of the chromosomal domain needed to support appropriate SCL transcription is unknown. Here we demonstrate that a 130-kilobase (kb) yeast artificial chromosome (YAC) containing the human SCL locus completely rescued the embryonic lethal phenotype ofscl−/− mice. Rescued YAC+scl−/− mice were born in appropriate Mendelian ratios, were healthy and fertile, and exhibited no detectable abnormality of yolk sac, fetal liver, or adult hematopoiesis. The human SCL protein can therefore substitute for its murine homologue. In addition, our results demonstrate that the human SCL YAC contains the chromosomal domain necessary to direct expression to the erythroid lineage and to all other tissues in which SCL performs a nonredundant essential function.

scholarly journals Extracellular vesicles of stromal origin target and support hematopoietic stem and progenitor cells

2017 ◽  
Vol 216 (7) ◽  
pp. 2217-2230 ◽  
Author(s):  
Gregoire Stik ◽  
Simon Crequit ◽  
Laurence Petit ◽  
Jennifer Durant ◽  
Pierre Charbord ◽  
...  
Keyword(s):  
Gene Expression ◽  
Progenitor Cells ◽  
Extracellular Vesicles ◽  
Ex Vivo ◽  
Fetal Liver ◽  
Critical Role ◽  
Molecular Signature ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells

Extracellular vesicles (EVs) have been recently reported as crucial mediators in cell-to-cell communication in development and disease. In this study, we investigate whether mesenchymal stromal cells that constitute a supportive microenvironment for hematopoietic stem and progenitor cells (HSPCs) released EVs that could affect the gene expression and function of HSPCs. By taking advantage of two fetal liver–derived stromal lines with widely differing abilities to maintain HSPCs ex vivo, we demonstrate that stromal EVs play a critical role in the regulation of HSPCs. Both supportive and nonsupportive stromal lines secreted EVs, but only those delivered by the supportive line were taken up by HSPCs ex vivo and in vivo. These EVs harbored a specific molecular signature, modulated the gene expression in HSPCs after uptake, and maintained the survival and clonogenic potential of HSPCs, presumably by preventing apoptosis. In conclusion, our study reveals that EVs are an important component of the HSPC niche, which may have major applications in regenerative medicine.

scholarly journals The transcriptional program controlled by the stem cell leukemia gene Scl/Tal1 during early embryonic hematopoietic development

Blood ◽  
2009 ◽  
Vol 113 (22) ◽  
pp. 5456-5465 ◽  
Author(s):  
Nicola K. Wilson ◽  
Diego Miranda-Saavedra ◽  
Sarah Kinston ◽  
Nicolas Bonadies ◽  
Samuel D. Foster ◽  
...  
Keyword(s):  
Stem Cell ◽  
Regulatory Networks ◽  
Transcriptional Control ◽  
Target Genes ◽  
Fetal Liver ◽  
Bioinformatic Analysis ◽  
Regulatory Elements ◽  
Hematopoietic Stem ◽  
A Genome

The basic helix-loop-helix transcription factor Scl/Tal1 controls the development and subsequent differentiation of hematopoietic stem cells (HSCs). However, because few Scl target genes have been validated to date, the underlying mechanisms have remained largely unknown. In this study, we have used ChIP-Seq technology (coupling chromatin immunoprecipitation with deep sequencing) to generate a genome-wide catalog of Scl-binding events in a stem/progenitor cell line, followed by validation using primary fetal liver cells and comprehensive transgenic mouse assays. Transgenic analysis provided in vivo validation of multiple new direct Scl target genes and allowed us to reconstruct an in vivo validated network consisting of 17 factors and their respective regulatory elements. By coupling ChIP-Seq in model cell lines with in vivo transgenic validation and sophisticated bioinformatic analysis, we have identified a widely applicable strategy for the reconstruction of stem cell regulatory networks in which biologic material is otherwise limiting. Moreover, in addition to revealing multiple previously unrecognized links to known HSC regulators, as well as novel links to genes not previously implicated in HSC function, comprehensive transgenic analysis of regulatory elements provided substantial new insights into the transcriptional control of several important hematopoietic regulators, including Cbfa2t3h/Eto2, Cebpe, Nfe2, Zfpm1/Fog1, Erg, Mafk, Gfi1b, and Myb.

A Critical Role for the Retinoblastoma Tumor Suppressor Gene in Hematopoietic Stem Cells.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2548-2548
Author(s):  
Hartmut Geiger ◽  
Marie-Dominique Filippi ◽  
Theodosia A. Kalfa ◽  
Deidre Daria
Keyword(s):  
Cell Cycle ◽  
Tumor Suppressor ◽  
Cell Function ◽  
Fetal Liver ◽  
Critical Role ◽  
Lymphoid Cells ◽  
Hematopoietic Stem ◽  
Retinoblastoma Tumor Suppressor ◽  
Retinoblastoma Tumor

Abstract The retinoblastoma tumor suppressor protein (RB) plays important roles in the control of the cell cycle, DNA-damage checkpoint, differentiation and apoptosis. It is estimated that RB is dysfunctional/inactivated in up to 40% of human leukemias. Positive as well as inhibitory signals are integrated into the phosphorylation of the RB protein to regulate the G1 to S-phase progression of the cell cycle. Despite the importance of RB in leukemia, the consequences of loss of RB on hematopoietic stem and progenitor cell (HSPC) function in vivo are still not clear and have been controversially discussed. Using Cre-enzyme expression driven by the hematopoietic specific Vav1-promotor, we generated mice that are constitutively deficient in RB (hemRb−/− animals) in HSPCs. HemRb−/− mice showed anemia with an increased number of reticulocytes in PB, consistent with a published role of RB in erythroid differentiation. In addition, the frequency of Mac-1 positive cells in BM was increased to 67% compared to 47% in control animals, whereas the frequency of B220 positive B-lymphoid cells was almost 10-fold reduced, without affecting the T-lymphoid compartment. HemRb−/− mice possessed a 3-fold enlarged spleen with a 5-fold increased number of colony-forming cells (CFCs) and severe extramedullary hematopoiesis, a phenotype also reported for animals transplanted with Rb−/− fetal liver cells. BM of hemRb−/− mice showed an almost 3-fold reduction of HSC frequency, measured by the cobblestone-area forming cell assay (CAFC) assay, but not a decrease in the number of HSCs determined by cell surface staining and flow cytometry. Upon transplantation into NOD/SCID animals or upon competitive transplantation into C57BL/6. CD45.1 animals, HSPCs from hemRb−/− mice contributed 4 to 6-fold less to hematopoiesis. HSPCs from hemRb−/− animals were neither impaired in their ability to home to the BM, nor did they show increased apoptosis. Finally, we detected a significant 4-fold decrease in stem cell function/numbers upon stress caused by 5-FU treatment in hemRB−/− mice compared to control animals. We conclude that upon transplantation/stress, HSPCs from hemRb−/− animals are impaired in their self-renewal function. HemRb−/− animals also showed a 2-fold increase in the frequency of CFCs in peripheral blood. As we detected no increased leukemia incidence in the hemRb−/− animals (now up to 1 year of age), loss of the tumor suppressor RB in hematopoietic cells might be regarded as necessary, but not sufficient for causing early onset leukemia. In summary, loss of RB results in context/localization dependent phenotypes in the hematopoietic hierarchy, influencing stem and progenitor cells in function, localization and differentiation ability.

scholarly journals Interactions Between c-kit and Stem Cell Factor Are Not Required for B-Cell Development In Vivo

Blood ◽  
1997 ◽  
Vol 89 (2) ◽  
pp. 518-525 ◽  
Author(s):  
Shunichi Takeda ◽  
Takeyuki Shimizu ◽  
Hans-Reimer Rodewald
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Fetal Liver ◽  
Critical Role ◽  
Cell Development ◽  
B Cell Development ◽  
Wild Type ◽  
Hematopoietic Stem

Abstract The receptor-type tyrosine kinase, c-kit is expressed in hematopoietic stem cells (HSC), myeloid, and lymphoid precursors. In c-kit ligand-deficient mice, absolute numbers of HSC are mildly reduced suggesting that c-kit is not essential for HSC development. However, c-kit− HSC cannot form spleen colonies or reconstitute hematopoietic functions in lethally irradiated recipient mice. Based on in in vitro experiments, a critical role of c-kit in B-cell development was suggested. Here we have investigated the B-cell development of c-kitnull mutant (W/W ) mice in vivo. Furthermore, day 13 fetal liver cells from wild type or W/W mice were transferred into immunodeficient RAG-2−/− mice. Surprisingly, transferred c-kit− cells gave rise to all stages of immature B cells in the bone marrow and subsequently to mature conventional B2, as well as B1, type B cells in the recipients to the same extent as transferred wild type cells. Hence, in contrast to important roles of c-kit in the expansion of HSC and the generation of erythroid and myeloid lineages and T-cell precursors, c-kit− HSC can colonize the recipient bone marrow and differentiate into B cells in the absence of c-kit.

scholarly journals The role of apoptosis in the development of AGM hematopoietic stem cells revealed by Bcl-2 overexpression

Blood ◽  
2004 ◽  
Vol 103 (11) ◽  
pp. 4084-4092 ◽  
Author(s):  
Claudia Orelio ◽  
Kirsty N. Harvey ◽  
Colin Miles ◽  
Robert A. J. Oostendorp ◽  
Karin van der Horn ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Fetal Liver ◽  
Regulatory Elements ◽  
Hematopoietic Stem ◽  
Hematopoietic System ◽  
Transcriptional Regulatory Elements ◽  
Tissue Region

Abstract Apoptosis is an essential process in embryonic tissue remodeling and adult tissue homeostasis. Within the adult hematopoietic system, it allows for tight regulation of hematopoietic cell subsets. Previously, it was shown that B-cell leukemia 2 (Bcl-2) overexpression in the adult increases the viability and activity of hematopoietic cells under normal and/or stressful conditions. However, a role for apoptosis in the embryonic hematopoietic system has not yet been established. Since the first hematopoietic stem cells (HSCs) are generated within the aortagonad-mesonephros (AGM; an actively remodeling tissue) region beginning at embryonic day 10.5, we examined this tissue for expression of apoptosis-related genes and ongoing apoptosis. Here, we show expression of several proapoptotic and antiapoptotic genes in the AGM. We also generated transgenic mice overexpressing Bcl-2 under the control of the transcriptional regulatory elements of the HSC marker stem cell antigen-1 (Sca-1), to test for the role of cell survival in the regulation of AGM HSCs. We provide evidence for increased numbers and viability of Sca-1+ cells in the AGM and subdissected midgestation aortas, the site where HSCs are localized. Most important, our in vivo transplantation data show that Bcl-2 overexpression increases AGM and fetal liver HSC activity, strongly suggesting that apoptosis plays a role in HSC development.

Distinct Roles of Integrins α6 and α4 in Fetal Liver Hematopoietic Stem and Progenitor Cell Homing.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 353-353
Author(s):  
Hong Qian ◽  
Elisabeth Georges-Labouesse ◽  
Alexander Nyström ◽  
Anna Domogatskaya ◽  
Karl Tryggvason ◽  
...  
Keyword(s):  
Fetal Liver ◽  
Critical Role ◽  
Liver Cells ◽  
Hematopoietic Stem ◽  
Knockout Mouse Model ◽  
Genetic Ablation ◽  
Integrin Α4 ◽  
Fetal Liver Cells

Abstract During development and after transplantation, intravenously injected hematopoietic stem and progenitor cells (HSPCs) selectively transmigrate through the sinusoidal walls into the bone marrow (BM) niches to engraft and reconstitute hematopoiesis. The rate of reconstitution following transplantation varies depending on the source of hematopoietic stem cells (HSCs) (To, et al 1992). However, the molecular pathways that control the homing of HSCs, in particular, of fetal HSCs are still not well understood. In the present study we studied the contribution of α6 and α4 integrins in homing of fetal liver HSPCs into adult BM by using function-blocking antibodies and an integrin α6 knockout mouse model. We found an ubiquitous expression of both integrin α6 and α4 receptors on fetal liver Lin−Sca-1+c-kit+ (LSK) HSPCs. Genetic ablation of integrin α6 resulted in reduced homing of fetal liver progenitors (HPCs) to BM of lethally irradiated adult recipients. In agreement with this, the integrin α6 antibody inhibited homing of fetal liver HPCs into BM and spleen. The role of integrin a6 in homing and engraftment of fetal liver HSCs was studied by a competitive repopulation assay by using integrin α6−/− or α6+/+ fetal liver cells. Absence of α6 integrin in fetal liver cells did not cause any engraftment defect or mobilization hypersensitivity as compared to wild-type cells. In agreement with this, anti-integrin α6 antibody did not either inhibit BM homing of short-term or long-term HSCs. In contrast, homing of fetal liver HSCs and HPCs to BM was virtually abrogated after treatment with integrin α4 antibody. Our results show that the α6 integrin receptors are functional during homing of fetal liver HPCs, but not multilineage repopulating HSC in vivo. Furthermore, we show the critical role of integrin α4 receptor for homing of both fetal liver HPCs and multilineage repopulating HSCs to BM, indicating distinct developmentally regulated functions for integrin α6 and α4 receptors during fetal hematopoiesis

scholarly journals A Ftz-F1-Containing Yeast Artificial Chromosome Recapitulates Expression of Steroidogenic Factor 1 in Vivo

2005 ◽  
Vol 19 (10) ◽  
pp. 2549-2563 ◽  
Author(s):  
Tatiana Karpova ◽  
Jeremy Presley ◽  
Rengasamy R. Manimaran ◽  
Serge P. Scherrer ◽  
Lovella Tejada ◽  
...  
Keyword(s):  
Biological Activity ◽  
Nuclear Receptor ◽  
Yeast Artificial Chromosome ◽  
Artificial Chromosome ◽  
Regulatory Elements ◽  
Orphan Nuclear Receptor ◽  
Hormone Production ◽  
Specific Expression ◽  
Steroidogenic Factor 1

Abstract Steroidogenic factor 1 (SF-1/Nr5a1) is an orphan nuclear receptor encoded by the Ftz-F1 gene and is required for gonad and adrenal development and regulation of hormone production within the reproductive and adrenal axes. To extend our understanding of Ftz-F1 and its role in SF-1 expression, we identified and characterized a yeast artificial chromosome (YAC) containing Ftz-F1. Within this YAC, Ftz-F1 is centrally located and flanked by genes encoding a second orphan nuclear receptor, germ cell nuclear factor, and proteasome (prosome, macropain) subunit β type 7. Three lines of transgenic mice carrying the YAC were generated and in two lines (lines 7 and 14), RT-PCR and ribonuclease protection analysis showed that expression of transgenic SF-1 mimicked that of endogenous SF-1, both spatially and quantitatively. In the third line (line 15), pituitary and hypothalamic expression were absent. Comparison of the integrated transgenes revealed that line 15 was truncated at the end of intron 4 and revealed a region within the locus that is responsible for SF-1 expression in the pituitary and hypothalamus. The line 14 transgene was introduced into a mouse strain lacking functional SF-1. Examination of SF-1-deficient, transgene-positive mice revealed that the YAC was able to rescue adrenal and gonad development, which normally arrests in the SF-1-null embryos and showed that the 153-kb transgene integrated in line 14 is sufficient to properly direct SF-1 expression and support its biological activity. Thus, the study defines a region of Ftz-F1 that contains the requisite set of regulatory elements to direct SF-1 cell-specific expression and all temporal and quantitative changes need for its biological activity.

scholarly journals The role of the PZP domain of AF10 in acute leukemia driven by AF10 translocations

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Brianna J. Klein ◽  
Anagha Deshpande ◽  
Khan L. Cox ◽  
Fan Xuan ◽  
Mohamad Zandian ◽  
...  
Keyword(s):  
Critical Role ◽  
Cellular Transformation ◽  
Acute Leukemias ◽  
Hematopoietic Stem ◽  
Nucleosome Core ◽  
Stem And Progenitor Cells ◽  
Transforming Activity

AbstractChromosomal translocations of the AF10 (or MLLT10) gene are frequently found in acute leukemias. Here, we show that the PZP domain of AF10 (AF10PZP), which is consistently impaired or deleted in leukemogenic AF10 translocations, plays a critical role in blocking malignant transformation. Incorporation of functional AF10PZP into the leukemogenic CALM-AF10 fusion prevents the transforming activity of the fusion in bone marrow-derived hematopoietic stem and progenitor cells in vitro and in vivo and abrogates CALM-AF10-mediated leukemogenesis in vivo. Crystallographic, biochemical and mutagenesis studies reveal that AF10PZP binds to the nucleosome core particle through multivalent contacts with the histone H3 tail and DNA and associates with chromatin in cells, colocalizing with active methylation marks and discriminating against the repressive H3K27me3 mark. AF10PZP promotes nuclear localization of CALM-AF10 and is required for association with chromatin. Our data indicate that the disruption of AF10PZP function in the CALM-AF10 fusion directly leads to transformation, whereas the inclusion of AF10PZP downregulates Hoxa genes and reverses cellular transformation. Our findings highlight the molecular mechanism by which AF10 targets chromatin and suggest a model for the AF10PZP-dependent CALM-AF10-mediated leukemogenesis.

scholarly journals ZMYND11-MBTD1 induces leukemogenesis through hijacking NuA4/TIP60 acetyltransferase complex and a PWWP-mediated chromatin association mechanism

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jie Li ◽  
Phillip M. Galbo ◽  
Weida Gong ◽  
Aaron J. Storey ◽  
Yi-Hsuan Tsai ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Fusion Gene ◽  
Ex Vivo ◽  
Chromosomal Translocation ◽  
Regulatory Elements ◽  
Hematopoietic Stem ◽  
Its Gene ◽  
Human Acute Myeloid Leukemia ◽  
Bromodomain Proteins

AbstractRecurring chromosomal translocation t(10;17)(p15;q21) present in a subset of human acute myeloid leukemia (AML) patients creates an aberrant fusion gene termed ZMYND11-MBTD1 (ZM); however, its function remains undetermined. Here, we show that ZM confers primary murine hematopoietic stem/progenitor cells indefinite self-renewal capability ex vivo and causes AML in vivo. Genomics profilings reveal that ZM directly binds to and maintains high expression of pro-leukemic genes including Hoxa, Meis1, Myb, Myc and Sox4. Mechanistically, ZM recruits the NuA4/Tip60 histone acetyltransferase complex to cis-regulatory elements, sustaining an active chromatin state enriched in histone acetylation and devoid of repressive histone marks. Systematic mutagenesis of ZM demonstrates essential requirements of Tip60 interaction and an H3K36me3-binding PWWP (Pro-Trp-Trp-Pro) domain for oncogenesis. Inhibitor of histone acetylation-‘reading’ bromodomain proteins, which act downstream of ZM, is efficacious in treating ZM-induced AML. Collectively, this study demonstrates AML-causing effects of ZM, examines its gene-regulatory roles, and reports an attractive mechanism-guided therapeutic strategy.

scholarly journals First blood: the endothelial origins of hematopoietic progenitors

Angiogenesis ◽  
2021 ◽  
Author(s):  
Giovanni Canu ◽  
Christiana Ruhrberg
Keyword(s):  
Stem Cells ◽  
Molecular Mechanisms ◽  
Vascular Endothelial Cells ◽  
Fetal Liver ◽  
Cell Types ◽  
Yolk Sac ◽  
Vascular Endothelial ◽  
Hematopoietic Stem ◽  
Close Proximity ◽  
Clinical Interest

AbstractHematopoiesis in vertebrate embryos occurs in temporally and spatially overlapping waves in close proximity to blood vascular endothelial cells. Initially, yolk sac hematopoiesis produces primitive erythrocytes, megakaryocytes, and macrophages. Thereafter, sequential waves of definitive hematopoiesis arise from yolk sac and intraembryonic hemogenic endothelia through an endothelial-to-hematopoietic transition (EHT). During EHT, the endothelial and hematopoietic transcriptional programs are tightly co-regulated to orchestrate a shift in cell identity. In the yolk sac, EHT generates erythro-myeloid progenitors, which upon migration to the liver differentiate into fetal blood cells, including erythrocytes and tissue-resident macrophages. In the dorsal aorta, EHT produces hematopoietic stem cells, which engraft the fetal liver and then the bone marrow to sustain adult hematopoiesis. Recent studies have defined the relationship between the developing vascular and hematopoietic systems in animal models, including molecular mechanisms that drive the hemato-endothelial transcription program for EHT. Moreover, human pluripotent stem cells have enabled modeling of fetal human hematopoiesis and have begun to generate cell types of clinical interest for regenerative medicine.

Sign in / Sign up

Export Citation Format

Share Document