scholarly journals Zinc Finger Protein 521 Regulates Early Hematopoiesis through Cell-Extrinsic Mechanisms in the Bone Marrow Microenvironment

2018 ◽  
Vol 38 (17) ◽  
Author(s):  
Courtney J. Fleenor ◽  
Tessa Arends ◽  
Hong Lei ◽  
Josefine Åhsberg ◽  
Kazuki Okuyama ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Cell Types ◽  
Bone Marrow Microenvironment ◽  
Cancer Therapies ◽  
Hematopoietic Stem ◽  
Finger Protein ◽  
Stem And Progenitor Cells

ABSTRACTZinc finger protein 521 (ZFP521), a DNA-binding protein containing 30 Krüppel-like zinc fingers, has been implicated in the differentiation of multiple cell types, including hematopoietic stem and progenitor cells (HSPC) and B lymphocytes. Here, we report a novel role for ZFP521 in regulating the earliest stages of hematopoiesis and lymphoid cell development via a cell-extrinsic mechanism. Mice with inactivatedZfp521genes (Zfp521−/−) possess reduced frequencies and numbers of hematopoietic stem and progenitor cells, common lymphoid progenitors, and B and T cell precursors. Notably, ZFP521 deficiency changes bone marrow microenvironment cytokine levels and gene expression within resident HSPC, consistent with a skewing of hematopoiesis away from lymphopoiesis. These results advance our understanding of ZFP521's role in normal hematopoiesis, justifying further research to assess its potential as a target for cancer therapies.

ALL Cells Mobilized by AMD3100 Are More Proliferative, and Remain In the Circulation Longer Than Normal HSC, Enhancing the Action of Vincristine

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2137-2137 ◽  
Author(s):  
Linda J. Bendall ◽  
Robert Welschinger ◽  
Florian Liedtke ◽  
Carole Ford ◽  
Aileen Dela Pena ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Peripheral Blood ◽  
Bone Marrow Microenvironment ◽  
Hematopoietic Progenitors ◽  
Cxcr4 Antagonist ◽  
Hematopoietic Stem ◽  
Stem And Progenitor Cells ◽  
Cell Mobilization ◽  
Cycle Dependent

Abstract Abstract 2137 The chemokine CXCL12, and its receptor CXCR4, play an essential role in homing and engraftment of normal hematopoietic cells in the bone marrow, with the CXCR4 antagonist AMD3100 inducing the rapid mobilization of hematopoietic stem and progenitor cells into the blood in mice and humans. We have previously demonstrated that AMD3100 similarly induces the mobilization of acute lymphoblastic leukemia (ALL) cells into the peripheral blood. The bone marrow microenvironment is thought to provide a protective niche for ALL cells, contributing to chemo-resistance. As a result, compounds that disrupt leukemic cell interactions with the bone marrow microenvironment are of interest as chemo-sensitizing agents. However, the mobilization of normal hematopoietic stem and progenitor cells may also increase bone marrow toxicity. To better evaluate how such mobilizing agents affect normal hematopoietic progenitors and ALL cells, the temporal response of ALL cells to the CXCR4 antagonist AMD3100 was compared to that of normal hematopoietic progenitor cells using a NOD/SCID xenograft model of ALL and BALB/c mice respectively. ALL cells from all 7 pre-B ALL xenografts were mobilized into the peripheral blood by AMD3100. Mobilization was apparent 1 hour and maximal 3 hours after drug administration, similar to that observed for normal hematopoietic progenitors. However, ALL cells remained in the circulation for longer than normal hematopoietic progenitors. The number of ALL cells in the circulation remained significantly elevated in 6 of 7 xenografts examined, 6 hours post AMD3100 administration, a time point by which circulating normal hematopoietic progenitor levels had returned to baseline. No correlation between the expression of the chemokine receptor CXCR4 or the adhesion molecules VLA-4, VLA-5 or CD44, and the extent or duration of ALL cell mobilization was detected. In contrast, the overall motility of the ALL cells in chemotaxis assays was predictive of the extent of ALL cell mobilization. This was not due to CXCL12-specific chemotaxis because the association was lost when correction for background motility was undertaken. In addition, AMD3100 increased the proportion of actively cells ALL cells in the peripheral blood. This did not appear to be due to selective mobilization of cycling cells but reflected the more proliferative nature of bone marrow as compared to peripheral blood ALL cells. This is in contrast to the selective mobilization of quiescent normal hematopoietic stem and progenitor cells by AMD3100. Consistent with these findings, the addition of AMD3100 to the cell cycle dependent drug vincristine, increased the efficacy of this agent in NOD/SCID mice engrafted with ALL. Overall, this suggests that ALL cells will be more sensitive to effects of agents that disrupt interactions with the bone marrow microenvironment than normal progenitors, and that combining agents that disrupt ALL retention in the bone marrow may increase the therapeutic effect of cell cycle dependent chemotherapeutic agents. Disclosures: Bendall: Genzyme: Honoraria.

The Disease-Related Bone Marrow Microenvironment Alters Hematopoietic Stem and Progenitor Function in Multiple Myeloma Patients

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2898-2898
Author(s):  
Ingmar Bruns ◽  
Ron-Patrick Cadeddu ◽  
Ines Brückmann ◽  
Sebastian Buest ◽  
Julia Fröbel ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Progenitor Cells ◽  
Bone Marrow Microenvironment ◽  
Tgf Beta ◽  
Hematopoietic Stem ◽  
Healthy Donors ◽  
Stem And Progenitor Cells ◽  
Related Bone Marrow

Abstract Abstract 2898 Multiple myeloma (MM) patients often suffer from hematopoietic impairment already at the time of diagnosis with anemia as the prevailing symptom. Given the overt affection of the bone marrow in MM patients by the invasion of malignant plasma cells, we hypothesized that hematopoietic insufficiency in these patients may originate from a functional impairment of hematopoietic stem and progenitor cells. Quantitative analysis of BM CD34+ HSPC cell subsets from MM patients and age-matched healthy donors showed a significant decline of all HSPC subsets including hematopoietic stem cells, common myeloid and lymphoid progenitors, granulocyte-macrophage progenitors and megakaryocyte-erythrocyte progenitors in MM patients. The greatest diminution was observed in megakaryocyte-erythrocyte progenitors (MEP) which were 4.9-fold reduced in comparison to healthy donors. Transcriptional analyses of CD34+ HSPC subsets revealed a significant deregulation of signaling pathways that was particularly striking for TGF beta signaling and suggested increased activation of this signaling pathway. Immunhistochemical staining of phosphorylated smad2, the downstream mediator of TGF receptor I kinase activation, in bone marrow sections and immunoblotting of purified CD34+ HSPC of MM patients confirmed the overactivation of TGF beta signaling. On a functional level, we observed significantly reduced long-term self-renewal and clonogenic growth, particularly of the erythroid precursors BFU-E and CFU-E, in CD34+ HSPC of MM patients which could be restored by inhibition of TGF beta signaling. Proliferation and cell cycle analyses revealed a significantly decreased proliferation activity in CD34+ HSPC and, particularly, MEP. Again, this was reversible after inhibition of TGF beta signaling. In addition, the transcriptional analyses showed disturbance of pathways involved in the adhesion and migration of HSPC and the gene encoding for the principal hyaluronan receptor CD44 throughout the HSPC subsets. This was corroborated by immunofluorescence imaging of CD44 on HSPC subsets showing a marked downregulation in the patients' cells. In line, the adhesion of CD34+ HSPC subsets to hyaluronan and their migration towards SDF-1 was significantly inhibited. Subsequent xenotransplantation of CD34+ HSPC from MM patients and healthy donors into myeloma-free recipients revealed even increased long-term engraftment of CD34+ HSPC obtained from MM patients and normal differentiation capacities suggesting that the observed functional alterations in fact depend on the MM-related bone marrow microenvironment. Our data show that hematopoietic impairment in patients with multiple myeloma originates, at least in part, from functional alterations of hematopoietic stem and progenitor cells. These alterations seem to depend on the disease-related changes of the bone marrow microenvironment. Currently, experiments are underway to elucidate in more detail the role of the microenvironment and the responsible structures for the impairment of HSPC in MM patients. These data will be presented. Disclosures: Kobbe: Celgene: Consultancy, Research Funding; Ortho Biotec: Consultancy.

Spatial Analysis of Hematopoietic Stem and Progenitor Cells in the Bone Marrow

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3570-3570
Author(s):  
Cesar Nombela-Arrieta ◽  
Brendan Harley ◽  
Elena Levantini ◽  
John E Mahoney ◽  
Gregory Pivarnik ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Laser Scanning ◽  
Imaging Techniques ◽  
Cell Types ◽  
Specific Cell ◽  
Hematopoietic Stem ◽  
Lineage Differentiation ◽  
Stem And Progenitor Cells ◽  
Laser Scanning Cytometry

Abstract Sustained production of all mature blood cell types relies on the continuous proliferation and differentiation of a rare population of self-renewing, multipotent hematopoietic stem cells (HSCs). HSC maintenance and lineage differentiation are strictly regulated by distinct microenvironments, termed niches, defined by cellular components, soluble regulators, and by the extracellular matrix. Definitive identification of the location as well as cellular and extracellular characteristics of HSC niches in the bone marrow (BM) has not been completed due to limitations of conventional imaging techniques. We have employed a novel imaging technology, Laser Scanning Cytometry (LSC) to define the localization of hematopoietic stem and progenitor cells (HSPCs) within different regions of the BM. LSC allows imaging and objective quantitative analysis of the anatomical position(s), number, and frequency of specific cell populations within the native tissue microenvironment. Analysis of whole femoral longitudinal sections of Bmi-GFP mice, in which GFP is expressed at its highest levels in HSPCs, revealed that within the bone diaphysis, HSPCs (Bmi-GFPhi c-kit+) cells were highly enriched in endosteal regions (within 100nm away from inner bone surface) compared to the central medullary region. Importantly, our data show that HSPCs are found at highest frequencies in the metaphysis of long bones, suggesting that these areas, which display characteristic morphological features, are functionally distinct from the diaphyseal region and a preferential location for HSPC-specific niches. We are currently employing LSC to identify HSPC niche cellular constituents by quantifying the relative frequency at which these cells are found in association with previously proposed niche-components such as osteoblasts, BM endothelial sinusoidal cells and CXCL12-abundant reticular cells. A detailed understanding of niche-derived signals regulating unique properties of HSCs will certainly prove relevant in human HSPC transplantation and cell therapy.

ZNF521 Is a Zinc Finger Protein That Prevents Differentiation Of Human MLL-AF9-Positive Myeloid Leukemic Cells

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1255-1255
Author(s):  
Giulia Morello ◽  
Sanja Aveic ◽  
Sonia Minuzzo ◽  
Barbara Michielotto ◽  
Silvia Bresolin ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Differentiation ◽  
Zinc Finger ◽  
Zinc Finger Protein ◽  
Leukemic Cells ◽  
Flow Cytometry Analysis ◽  
Hematopoietic Stem ◽  
Qrt Pcr ◽  
Finger Protein

Abstract Introduction MLL- rearranged acute myeloid leukemia (AML) remains a type of leukemia difficult to treat, for which alternative and more adequate treatment options are still urgently needed. The zinc finger protein 521 (ZNF521/EHZF) is a protein with multiple zinc finger domains that plays an essential role in the homeostasis of the hematopoietic stem/progenitor cell compartment. ZNF521 mRNA is highly expressed in hematopoietic stem and progenitor cells and its levels rapidly decrease during cell differentiation. Gene expression studies demonstrated that ZNF521 transcripts are abundantly expressed in MLL-rearranged AML. However, the functional significance of this up-regulation in AML with MLLrearrangements remains largely unknown. Methods and results Quantitative RT-PCR analysis (qRT-PCR) confirmed that ZNF521 expression was significantly up regulated in a cohort of MLL-rearranged pediatric AML patients (n=80) compared with other AML subtypes (n=30) together with healthy bone marrow samples (n=7, p<0.0001), and AML cell lines with MLL fusion (THP-1, NOMO-1, ML2). To investigate the role of ZNF521, we performed shRNA-mediated knockdown of ZNF521 in MLL-rearranged AML cell lines THP-1 and NOMO-1, in which a reduced transcript levels of 60-70% resulted in a severe reduction of proliferation and largely abolished colony formation in methylcellulose, where residual colonies were also smaller than control. Next, flow-cytometry analysis showed that observed proliferation reduction was associated with a block of cell cycle in G1 phase (shRNA/control vs shRNA/ZNF521 G1=45.4% vs G1=60.4%, n=3, p<0.05) and a late cell death induction (Annexin/PI positive cells: shRNA/control 21.4±0.5% vs shRNA/ZNF521 30.1±0.3% 3 weeks, n=3, p<0.0001). Subsequently, morphology analysis of May-Grunwald-Giemsa stained cytospins identified a large number of monocytic cells differentiating into macrophages. This observation was further validated by flow-cytometry analysis that confirmed the increased levels of CD11b and CD14 antigens as sign of monocytic differentiation, indicating a tendency of ZNF521 when over-expressed to prevent cell differentiation. Then, we treated THP-1 cells with ATRA to induce differentiation and demonstrated by qRT-PCR a significant reduction of ZNF521 mRNA expression, supporting its role in blocking differentiation in MLL-rearranged leukemic cells. Hence, to validate the specificity of these effects in vivo, we transplanted leukemic bone marrow cells from different MLL-AF9 AML pediatric patients (n=4) into immunodeficient mice. All mice developed AML by 7 to 9 weeks after transplantation. Then, the ex vivo cells were transduced with ZNF521 shRNA and showed morphology changes similar to those observed in vitro, with typical features of maturation. Conclusions Collectively, these results demonstrate that ZNF521 plays an important role in MLL-AF9-induced AML leukemia wherein it maintains a block of differentiation. Thus, our findings make ZNF521 a novel attractive target for therapeutic intervention in MLL-rearranged AML. However, further studies on the function of ZNF521 in MLL-rearranged AML and on the possibility to block it are required. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Bone Angiogenesis and Vascular Niche Remodeling in Stress, Aging, and Diseases

2020 ◽  
Vol 8 ◽  
Author(s):  
Sina Stucker ◽  
Junyu Chen ◽  
Fiona E. Watt ◽  
Anjali P. Kusumbe
Keyword(s):  
Bone Marrow ◽  
Progenitor Cells ◽  
Cell Types ◽  
Stress Factors ◽  
Hematopoietic Stem ◽  
Perivascular Cell ◽  
Vascular Niche ◽  
Bm Niche ◽  
Highly Sensitive ◽  
Stem And Progenitor Cells

The bone marrow (BM) vascular niche microenvironments harbor stem and progenitor cells of various lineages. Bone angiogenesis is distinct and involves tissue-specific signals. The nurturing vascular niches in the BM are complex and heterogenous consisting of distinct vascular and perivascular cell types that provide crucial signals for the maintenance of stem and progenitor cells. Growing evidence suggests that the BM niche is highly sensitive to stress. Aging, inflammation and other stress factors induce changes in BM niche cells and their crosstalk with tissue cells leading to perturbed hematopoiesis, bone angiogenesis and bone formation. Defining vascular niche remodeling under stress conditions will improve our understanding of the BM vascular niche and its role in homeostasis and disease. Therefore, this review provides an overview of the current understanding of the BM vascular niches for hematopoietic stem cells and their malfunction during aging, bone loss diseases, arthritis and metastasis.

scholarly journals A Meta-Analytic Single-Cell Atlas of Mouse Bone Marrow Hematopoietic Development

2021 ◽  
Author(s):  
Benjamin D Harris ◽  
John Lee ◽  
Jesse Gillis
Keyword(s):  
Bone Marrow ◽  
Single Cell ◽  
Progenitor Cells ◽  
Cell Types ◽  
Marker Genes ◽  
Mouse Bone Marrow ◽  
Clear Understanding ◽  
Hematopoietic Stem ◽  
Hematopoietic Development ◽  
Stem And Progenitor Cells

The clinical importance of the hematopoietic system makes it one of the most heavily studied lineages in all of biology. A clear understanding of the cell types and functional programs during hematopoietic development is central to research in aging, cancer, and infectious diseases. Known cell types are traditionally identified by the expression of proteins on the surface of the cells. Stem and progenitor cells defined based on these markers are assigned functions based on their lineage potential. The rapid growth of single cell RNA sequencing technologies (scRNAseq) provides a new modality for evaluating the cellular and functional landscape of hematopoietic stem and progenitor cells. The popularity of this technology among hematopoiesis researchers enables us to conduct a robust meta-analysis of mouse bone marrow scRNAseq data. Using over 300,000 cells across 12 datasets, we evaluate the classification and function of cell types based on discrete clustering, in silico FACS sorting, and a continuous trajectory. We identify replicable signatures that define cell types based on genes and known cellular functions. Additionally, we evaluate the conservation of signatures associated with erythroid and monocyte lineage development across species using co-expression networks. The co-expression networks predict the effectiveness of the signature at identifying erythroid and monocyte cells in zebrafish and human scRNAseq data. Together, this analysis provides a robust reference, particularly marker genes and functional annotations, for future experiments in hematopoietic development.

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