scholarly journals spib is required for primitive myeloid development in Xenopus

Blood ◽  
2008 ◽  
Vol 112 (6) ◽  
pp. 2287-2296 ◽  
Author(s):  
Ricardo M. B. Costa ◽  
Ximena Soto ◽  
Yaoyao Chen ◽  
Aaron M. Zorn ◽  
Enrique Amaya
Keyword(s):  
Blood Cells ◽  
Myeloid Cells ◽  
Time Lapse ◽  
Morpholino Knockdown ◽  
Myeloid Development ◽  
Blood Formation ◽  
Ets Transcription Factor ◽  
Antisense Morpholino ◽  
Definitive Hematopoiesis ◽  
Genetic Hierarchy

Abstract Vertebrate blood formation occurs in 2 spatially and temporally distinct waves, so-called primitive and definitive hematopoiesis. Although definitive hematopoiesis has been extensively studied, the development of primitive myeloid blood has received far less attention. In Xenopus, primitive myeloid cells originate in the anterior ventral blood islands, the equivalent of the mammalian yolk sac, and migrate out to colonize the embryo. Using fluorescence time-lapse video microscopy, we recorded the migratory behavior of primitive myeloid cells from their birth. We show that these cells are the first blood cells to differentiate in the embryo and that they are efficiently recruited to embryonic wounds, well before the establishment of a functional vasculature. Furthermore, we isolated spib, an ETS transcription factor, specifically expressed in primitive myeloid precursors. Using spib antisense morpholino knockdown experiments, we show that spib is required for myeloid specification, and, in its absence, primitive myeloid cells retain hemangioblast-like characteristics and fail to migrate. Thus, we conclude that spib sits at the top of the known genetic hierarchy that leads to the specification of primitive myeloid cells in amphibians.

scholarly journals The pancreas anatomy conditions the origin and properties of resident macrophages

2015 ◽  
Vol 212 (10) ◽  
pp. 1497-1512 ◽  
Author(s):  
Boris Calderon ◽  
Javier A. Carrero ◽  
Stephen T. Ferris ◽  
Dorothy K. Sojka ◽  
Lindsay Moore ◽  
...  
Keyword(s):  
Steady State ◽  
Blood Cells ◽  
Myeloid Cells ◽  
Alternative Activation ◽  
Macrophage Phenotype ◽  
Phenotypic Properties ◽  
Complete Replacement ◽  
Activation Profile ◽  
Anatomical Localization ◽  
Definitive Hematopoiesis

We examine the features, origin, turnover, and gene expression of pancreatic macrophages under steady state. The data distinguish macrophages within distinct intrapancreatic microenvironments and suggest how macrophage phenotype is imprinted by the local milieu. Macrophages in islets of Langerhans and in the interacinar stroma are distinct in origin and phenotypic properties. In islets, macrophages are the only myeloid cells: they derive from definitive hematopoiesis, exchange to a minimum with blood cells, have a low level of self-replication, and depend on CSF-1. They express Il1b and Tnfa transcripts, indicating classical activation, M1, under steady state. The interacinar stroma contains two macrophage subsets. One is derived from primitive hematopoiesis, with no interchange by blood cells and alternative, M2, activation profile, whereas the second is derived from definitive hematopoiesis and exchanges with circulating myeloid cells but also shows an alternative activation profile. Complete replacement of islet and stromal macrophages by donor stem cells occurred after lethal irradiation with identical profiles as observed under steady state. The extraordinary plasticity of macrophages within the pancreatic organ and the distinct features imprinted by their anatomical localization sets the base for examining these cells in pathological conditions.

Development of Multi-Lineage Hematopoiesis in Two Novel Zebrafish runx1 mutants

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2373-2373
Author(s):  
Erica Bresciani ◽  
Blake Carrington ◽  
Erika Mijin Kwon ◽  
Marypat Jones ◽  
Stephen Wincovitch ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hematopoietic Stem Cells ◽  
Blood Cells ◽  
Conflicts Of Interest ◽  
Time Lapse ◽  
Loss Of Function ◽  
Transcription Activator ◽  
Zebrafish Model ◽  
Hematopoietic Stem ◽  
Definitive Hematopoiesis

Abstract Long term hematopoietic stem cells are essential for the life-long maintenance of the hematopoietic system of an organism. The transcription factor RUNX1 is required for the emergence of definitive hematopoietic stem cells (HSCs) from the hemogenic endothelium during the embryo development. Runx1 knockout mouse embryos lack all definitive blood lineages and cannot survive past embryonic day 13. However, we previously showed that zebrafish homozygous for an ENU-induced nonsense mutation in runx1 (runx1W84X/W84X) were able to recover from a larval "bloodless" phase and develop to fertile adults with multi-lineage hematopoiesis, suggesting the formation of runx1-independent adult HSCs. However, our finding was based on a single zebrafish model, which requires verification in additional, independent models. In order to further investigate if a RUNX1-independent pathway exists for the formation of adult HSCs, we generated two new runx1 mutants, a deletion of 8 bp (runx1del8/del8) and a deletion of 25 bp (runx1del25/del25) within exon 4 of runx1, respectively, using the Transcription activator-like effector nucleases (TALENs) technology. These mutations cause frameshifts and premature terminations within the runt-homology domain,, resulting in loss of function of runx1 (runx1-/-). Both runx1del8/del8 and runx1del25/del25 mutant embryos had normal primitive hematopoiesis but failed to develop definitive hematopoiesis. Time-lapse recordings with confocal microscopy revealed that, indeed, there was no emergence of HSCs from the ventral wall of dorsal aorta in the runx1-/- embryos. The runx1-/- larvae gradually lost circulating primitive blood cells and became bloodless between 8 and 14 days post fertilization (dpf). However they gradually regained circulating blood cells between 15 and 20 dpf. Eventually, about 40% of runx1del8/del8 and runx1del25/del25 mutants developed to fertile adults with circulating blood cells of multi-lineages. Taken together, our data is consistent with the previously described runx1W84X/W84X phenotype and supports the possibility of a runx1-independent mechanism for HSC formation and definitive hematopoiesis. Disclosures No relevant conflicts of interest to declare.

scholarly journals Mouse Emi2 is required to enter meiosis II by reestablishing cyclin B1 during interkinesis

2006 ◽  
Vol 174 (6) ◽  
pp. 791-801 ◽  
Author(s):  
Suzanne Madgwick ◽  
David V. Hansen ◽  
Mark Levasseur ◽  
Peter K. Jackson ◽  
Keith T. Jones
Keyword(s):  
Fluorescent Protein ◽  
Polar Body ◽  
Cyclin B1 ◽  
Anaphase Promoting Complex ◽  
Morpholino Knockdown ◽  
Short Time ◽  
Mitotic Inhibitor ◽  
Antisense Morpholino ◽  
Meiosis I

During interkinesis, a metaphase II (MetII) spindle is built immediately after the completion of meiosis I. Oocytes then remain MetII arrested until fertilization. In mouse, we find that early mitotic inhibitor 2 (Emi2), which is an anaphase-promoting complex inhibitor, is involved in both the establishment and the maintenance of MetII arrest. In MetII oocytes, Emi2 needs to be degraded for oocytes to exit meiosis, and such degradation, as visualized by fluorescent protein tagging, occurred tens of minutes ahead of cyclin B1. Emi2 antisense morpholino knockdown during oocyte maturation did not affect polar body (PB) extrusion. However, in interkinesis the central spindle microtubules from meiosis I persisted for a short time, and a MetII spindle failed to assemble. The chromatin in the oocyte quickly decondensed and a nucleus formed. All of these effects were caused by the essential role of Emi2 in stabilizing cyclin B1 after the first PB extrusion because in Emi2 knockdown oocytes a MetII spindle was recovered by Emi2 rescue or by expression of nondegradable cyclin B1 after meiosis I.

scholarly journals Differential Effects of RASA3 Mutations on Hematopoiesis are Profoundly Influenced by Genetic Background and Molecular Variant

2020 ◽  
Author(s):  
Raymond F. Robledo ◽  
Steven L. Ciciotte ◽  
Joel H. Graber ◽  
Yue Zhao ◽  
Amy J. Lambert ◽  
...  
Keyword(s):  
Progenitor Cells ◽  
Blood Cells ◽  
Genetic Background ◽  
White Blood Cells ◽  
Independent Effect ◽  
Mouse Strains ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells ◽  
Blood Formation ◽  
Molecular Variant

AbstractStudies of the severely pancytopenic scat mouse model first demonstrated the crucial role of RASA3, a dual RAS and RAP GTPase activating protein (GAP), in hematopoiesis. RASA3 is required for survival in utero; germline deletion is lethal at E12.5-13.5 due to severe hemorrhage and decreased fetal liver erythropoiesis. Conditional deletion in hematopoietic stem and progenitor cells (HSPCs) using Vav-Cre recapitulates the null phenotype demonstrating that RASA3 is required at the stem and progenitor level to maintain blood vessel development and integrity and effective blood production. In adults, bone marrow blood cell production and spleen stress erythropoiesis are suppressed significantly upon induction of RASA3 deficiency, leading to pancytopenia and death within two weeks. Notably, RASA3 missense mutations in mouse models scat (G125V) and hlb381 (H794L) show dramatically different hematopoietic consequences specific to both genetic background and molecular variant. Global transcriptomic studies in scat suggest potential targets to ameliorate disease progression.Author SummaryHematopoiesis is the process by which blood cells are formed. The individual must have a normal complement of red blood cells to prevent anemia, platelets to control bleeding, and white blood cells to maintain immune functions. All blood cells are derived from hematopoietic stem cells that differentiate into progenitor cells that then develop into mature circulating cells. We studied several mouse strains carrying different mutations in RASA3. We show that RASA3 is required at the earliest stages of blood formation, the stem and progenitor cells, and that the complement of genes other than RASA3, or the genetic background of the mutant strain, profoundly alters the overall effect on blood formation. Further, the molecular nature of the mutation in RASA3 also has a profound and independent effect on overall blood formation. One strain, designated scat, suffers cyclic anemia characterized by severe anemic crisis episodes interspersed with remissions where the anemia significantly improves. Comparison of scat crisis and remission hematopoietic stem and progenitor cells reveals striking differences in gene expression. Analyses of these expression differences provide clues to processes that potentially drive improvement of anemia in scat and provide new avenues to pursue in future studies to identify novel therapeutics for anemia.

Gfi-1 Represses PU.1 Activity To Promote Granulocyte over Macrophage Differentiation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2722-2722
Author(s):  
Richard E. Dahl ◽  
Sangeeta R. Iyer ◽  
Dorothy D. Cuylear ◽  
M. Celeste Simon
Keyword(s):  
Transcriptional Activity ◽  
Target Genes ◽  
Myeloid Cells ◽  
Hematopoietic Progenitor Cell ◽  
Macrophage Differentiation ◽  
Myeloid Development ◽  
Immature Myeloid Cells ◽  
Primary Bone ◽  
Primary Bone Marrow

Abstract Mice lacking the zinc finger transcriptional repressor protein Gfi-1 are neutropenic. These mice generate abnormal immature myeloid cells exhibiting characteristics of both macrophages and granulocytes. Interestingly these immature Gfi-1−/− myeloid cells overexpress target genes of the PU.1 transcription factor: M-CSF receptor (M-CSFR) and PU.1 itself. Because of this we sought to determine if Gfi-1 modulates the transcriptional activity of PU.1. Here we demonstrate that Gfi-1 physically associates with PU.1 and represses PU.1- dependent transcription from the M-CSFR promoter. This interaction is functionally relevant as Gfi-1 blocks PU.1- dependent macrophage differentiation, but not granulocyte differentiation of a multipotential hematopoietic progenitor cell line. Additionally infection of primary bone marrow progenitors with a Gfi-1 retrovirus promotes granulocyte differentiation at the expense of macrophage differentiation. In contrast, a Gfi-1 mutant lacking repressor activity strongly promotes macrophage differentiation of hematopoietic progenitors. In transient transfections this Gfi-1 mutant not only blocks Gfi-1 repression of PU.1 transcriptional activity but C/EBP alpha mediated repression as well. From this data we hypothesize that Gfi-1 along with other transcriptional regulators target PU.1 for repression in the granulocyte-macrophage progenitor (GMP) in order to direct granulocyte differentiation. If true decreasing the concentration of PU.1 may decrease the need for Gfi-1 in directing granulocyte development. We are currently testing this in vivo by examining myeloid development in PU.1+/−Gfi-1−/− mice.

Membrane-Bound Human Stem Cell Factor Promotes Differentiation of Human Granulocytes and Mast Cells In Vivo,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3419-3419
Author(s):  
Shinsuke Takagi ◽  
Yoriko Saito ◽  
Atsushi Hijikata ◽  
Satoshi Tanaka ◽  
Takashi Watanabe ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Mast Cells ◽  
Stem Cell Factor ◽  
Myeloid Cells ◽  
Human Stem Cell ◽  
Myeloid Development ◽  
Membrane Bound ◽  
Human Stem Cell Factor

Abstract Abstract 3419 Recently, advances in xenograft models for human hemamtopoietic stem cells (HSCs), or the humanized mice, have begun to allow investigators to examine the differentiation of human hematopoietic and immune cells in vivo. However, lymphoid-skewed human hematopoietic development in the mouse bone marrow is one of the remaining limitations in the humanized mouse models. The inefficient human myeloid development could at least partly be attributed to the mouse microenvironment not fully supporting differentiation and maturation of human myeloid lineage. To overcome this problem, we focused on the role of membrane-bound human stem cell factor in supporting the maintenance of human HSCs and inducing the development of human myeloid cells and created human stem cell factor transgenic NOD/SCID/IL2rgKO (hSCF Tg NSG) mice. Transplantation of 5000–50000 cord blood-derived Lin-CD34+CD38- cells resulted in significantly higher engraftment of human CD45+ leukocytes at 3–6 months post-transplantation in the bone marrow, spleen, and peripheral blood of hSCF Tg NSG recipients compared with those of non-transgenic NSG recipients. The enhanced human CD45+ engraftment was most prominent in the bone marrow (hSCF Tg recipients: 98.0 +/− 1.3%, n= 15, non-Tg NSG controls: 75.3 +/− 7.3%, n=7). In the bone marrow, the frequency of human CD33+ myeloid cells within the total human CD45+ population was significantly higher in the hSCF Tg NSG recipients than in the non-Tg NSG recipients and constituted the majority of human hematopoietic cells (hSCF Tg recipients: 54.6 +/− 4.5%, n=15 and non-Tg NSG controls: 29.3 +/− 4.0%, n=7). Flow cytometric analysis demonstrated that the majority of engrafted human myeloid cells in the hSCF Tg recipient bone marrow were side-scatter high, HLA-DR negative granulocytes. Reflecting the effect of human SCF on the development of human mast cells, human c-Kit+CD203c+ mast cells were identified in the bone marrow, spleen, and gastrointestinal tracts of the hSCF Tg NSG recipients. Altogether, the in vivo humanized mouse model demonstrates the essential role of membrane-bound SCF in human myeloid development. The hSCF Tg NSG humanized mice may facilitate the in vivo investigation of human HSCs, myeloid progenitors and mature myeloid lineage. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Heterogeneous timing of asexual cycles in Plasmodium falciparum quantified by extended time-lapse microscopy

2018 ◽  
Author(s):  
Heungwon Park ◽  
Shuqiang Huang ◽  
Katelyn A. Walzer ◽  
Lingchong You ◽  
Jen-Tsan Ashley Chi ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Single Cells ◽  
Time Lapse ◽  
Bimodal Distribution ◽  
Host Cells ◽  
Cycle Period ◽  
Human Red Blood Cells ◽  
Asexual Cycle

ABSTRACTMalarial fever arises from the synchronous bursting of human red blood cells by the Plasmodium parasite. The released parasites re-infect neighboring red blood cells and undergo another asexual cycle of differentiation and proliferation for 48 hours, before again bursting synchronously. The synchrony of bursting is lost during in vitro culturing of the parasite outside the human body, presumably because the asexual cycle is no longer entrained by host-specific circadian cues. Therefore, most in vitro malaria studies have relied on the artificial synchronization of the parasite population. However, much remains unknown about the degree of timing heterogeneity of asexual cycles and how artificial synchronization may affect this timing. Here, we combined time-lapse fluorescence microscopy and long-term culturing to follow single cells and directly measure the heterogeneous timing of in vitro asexual cycles. We first demonstrate that unsynchronized laboratory cultures are not fully asynchronous and the parasites exhibit a bimodal distribution in their first burst times. We then show that synchronized and unsynchronized cultures had similar asexual cycle periods, which indicates that artificial synchronization does not fundamentally perturb asexual cycle dynamics. Last, we demonstrate that sibling parasites descended from the same schizont exhibited significant variation in asexual cycle period, although smaller than the variation between non-siblings. The additional variance between non-siblings likely arises from the variable environments and/or developmental programs experienced in different host cells.

scholarly journals Redundant mechanisms driven independently by RUNX1 and GATA2 for hematopoietic development

2021 ◽  
Author(s):  
Erica Bresciani ◽  
Blake Carrington ◽  
Kai Yu ◽  
Erika Kim ◽  
Tao Zhen ◽  
...  
Keyword(s):  
Blood Cells ◽  
Mouse Embryos ◽  
Null Mouse ◽  
Compensatory Mechanism ◽  
Hematopoietic Stem ◽  
Hematopoietic Development ◽  
Genetic Inactivation ◽  
Signature Genes ◽  
Single Cell Rna Sequencing ◽  
Definitive Hematopoiesis

RUNX1 is essential for the generation of hematopoietic stem cells (HSCs). Runx1 null mouse embryos lack definitive hematopoiesis and die in mid-gestation. However, even though zebrafish embryos with a runx1 W84X mutation have defects in early definitive hematopoiesis, some runx1W84X/W84X embryos can develop to fertile adults with blood cells of multi-lineages, raising the possibility that HSCs can emerge without RUNX1. Here, using three new zebrafish runx1-/- lines we uncovered the compensatory mechanism for runx1-independent hematopoiesis. We show that, in the absence of a functional runx1, a cd41-GFP+ population of hematopoietic precursors still emerge from the hemogenic endothelium and can colonize the hematopoietic tissues of the mutant embryos. Single-cell RNA sequencing of the cd41-GFP+ cells identified a set of runx1-/--specific signature genes during hematopoiesis. Significantly, gata2b, which normally acts upstream of runx1 for the generation of HSCs, was increased in the cd41-GFP+ cells in runx1- /- embryos. Interestingly, genetic inactivation of both gata2b and its paralog, gata2a, did not affect hematopoiesis. However, knocking out runx1 and any three of the four alleles of gata2a and gata2b abolished definitive hematopoiesis. Gata2 expression was also upregulated in hematopoietic cells in Runx1-/- mice, suggesting the compensatory mechanism is conserved. Our findings indicate that RUNX1 and GATA2 serve redundant roles for HSC production, acting as safeguard for each other.

scholarly journals GABP Cooperates With c-Myb and C/EBP to Activate the Neutrophil Elastase Promoter

Blood ◽  
1997 ◽  
Vol 89 (12) ◽  
pp. 4546-4554 ◽  
Author(s):  
Issarang Nuchprayoon ◽  
Carl P. Simkevich ◽  
Menglin Luo ◽  
Alan D. Friedman ◽  
Alan G. Rosmarin
Keyword(s):  
Transcription Factor ◽  
Neutrophil Elastase ◽  
Binding Sites ◽  
Myeloid Cells ◽  
Myeloid Differentiation ◽  
Related Protein ◽  
3T3 Cells ◽  
Ets Transcription Factor ◽  
Nih 3T3 ◽  
Transcription Factor Complex

Abstract Neutrophil elastase (NE) is a serine protease that is transcriptionally regulated during early myeloid differentiation. The murine NE (mNE) promoter contains functionally important c-Myb, C/EBP, and ets binding sites. Deletion of the ets site reduced promoter activity by 90%. Although the ets transcription factor, PU.1, bound to this ets site, it only modestly activated the mNE promoter. Here, we show that a second transcription factor from myeloid cells — GABP — binds to the mNE ets site but strongly activates the mNE promoter. GABP is a heteromeric transcription factor complex that consists of GABPα, an ets factor, and GABPβ, a Notch-related protein. GABPα bound to the mNE ets site and, in turn, recruited GABPβ to form a transcriptionally active complex. GABPα and PU.1 competed with each other for binding to the mNE ets site. GABP increased the activity of the mNE promoter sevenfold in U937 myeloid cells. GABP cooperated with c-Myb and C/EBPα to activate the mNE promoter more than 85-fold in otherwise nonpermissive, nonhematopoietic NIH 3T3 cells. Thus, GABP binds to the crucial mNE promoter ets site and powerfully activates its expression alone and in cooperation with the transcription factors c-Myb and C/EBP.

Sign in / Sign up

Export Citation Format

Share Document