Xenotransplantation of immunodeficient mice with mobilized human blood CD34+ cells provides an in vivo model for human megakaryocytopoiesis and platelet production

Blood ◽  
2001 ◽  
Vol 97 (6) ◽  
pp. 1635-1643 ◽  
Author(s):  
Lia E. Perez ◽  
Henry M. Rinder ◽  
Chao Wang ◽  
Jayne B. Tracey ◽  
Noel Maun ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Ex Vivo ◽  
Human Platelets ◽  
Scid Mice ◽  
In Vivo Model ◽  
Specific Flow ◽  
Platelet Production

The study of megakaryocytopoiesis has been based largely on in vitro assays. We characterize an in vivo model of megakaryocyte and platelet development in which human peripheral blood stem cells (PBSCs) differentiate along megakaryocytic as well as myeloid/lymphoid lineages in sublethally irradiated nonobese diabetic/severe combined immunodeficient (NOD-SCID) mice. Human hematopoiesis preferentially occurs in the bone marrow of the murine recipients, and engraftment is independent of exogenous cytokines. Human colony-forming units–megakaryocyte (CFU-MK) develop predominantly in the bone marrow, and their presence correlates with the overall degree of human cell engraftment. Using a sensitive and specific flow cytometric assay, human platelets are detected in the peripheral blood from weeks 1 to 8 after transplantation. The number of circulating human platelets peaks at week 3 with a mean of 20 × 109/L. These human platelets are functional as assessed by CD62P expression in response to thrombin stimulation in vitro. Exogenous cytokines have a detrimental effect on CFU-MK production after 2 weeks, and animals treated with these cytokines have no circulating platelets 8 weeks after transplantation. Although cytokine stimulation of human PBSCs ex vivo led to a significant increase in CFU-MK, CD34+/41+, and CD41+ cells, these ex vivo expanded cells provided only delayed and transient platelet production in vivo, and no CFU-MK developed in vivo after transplantation. In conclusion, xenogeneic transplantation of human PBSCs into NOD/SCID mice provides an excellent in vivo model to study human megakaryocytopoiesis and platelet production.

High-Vorticity with Periodic Flow Enhances in Vitro Biogenesis of Healthy Platelets from iPSC-Derived-Megakaryocytes

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2181-2181
Author(s):  
Yukitaka Ito ◽  
Sou Nakamura ◽  
Tomohiro Shigemori ◽  
Naoshi Sugimoto ◽  
Yoshikazu Kato ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Steady State ◽  
Ex Vivo ◽  
Annexin V ◽  
Poor Quality ◽  
Flow Chamber ◽  
Physical Parameters ◽  
Platelet Production

Abstract Each transfusion requires 200-300 billion platelets in patients with thrombocytopenia. To continuously supply such a huge number of platelets by ex vivo generation, two distinct steps, megakaryopoiesis and platelet shedding, must be both considered. For the former, one approach is to increase the number of source cell, megakaryocytes. For example, the immortalized megakaryocyte cell line (imMKCL) system uses self-renewing megakaryocyte (MK) cell lines derived from induced pluripotent stem cells (iPSCs) (Nakamura et al., Cell Stem Cell, 2014). For the latter, there have been an idea of bioreactors whereby shedding of platelets from proplatelets could be promoted by flow-dependent shear force within the bone marrow in vivo (Junt et al., Science, 2007; Zhang et al., J Exp Med, 2012). Based upon this idea, we constructed a flow chamber type bioreactor recapitulating in vivo blood flow shear rate. However, this bioreactor failed to efficiently yield platelets, and moreover, the produced platelets had poor quality as indicated by high Annexin V levels (Exp Hematol, 2011 and unpublished result). Recently, we demonstrated two different kinetics of platelet biogenesis from bone marrow MKs, whereby either thrombopoietin (TPO) mostly regulates steady-state shedding of platelets from proplatelets, or interleukin-a (IL-1a) triggers inflammation-dependent rupture of MK cytoplasm contributing to a quick increase of platelet count at higher rate (Nishimura et al., J Cell Biol, 2015). However, the rupture type platelets revealed shorter half-life with relatively higher Annexin V levels. Therefore, to gain insights from platelet biogenesis in vivo, we focused on biophysical analysis of steady-state platelet biogenesis via proplatelets in bone marrow. Our observations strongly indicated that the presence of 'vorticity' defined by vortex turbulence in addition to shear-dependent 'stress' and 'strain' correlates with the efficient shedding of competent platelets. From this new finding, we developed an alternative bioreactor system, which enabled generation of 100 billion platelets from imMKCL in a 16L-scale liquid culture condition without any adherent machinery using two 10L-bioreactors. Furthermore, platelets generated via new bioreactors showed low Annexin V levels (<10-15%) and shortened bleeding time post transfusion into NOG mice and rabbits with thrombocytopenia, comparable to human blood product platelets. Regarding the platelet production using WAVE bag system (GE healthcare, UK), the system is already clinically available for cord blood cell expansion in most countries, but lacks adequate levels of vorticity and shear strain/stress. Accordingly, the produced platelets had high Annexin V levels (i.e., 50-65%) as well as diminished yield efficiency (P<0.001). In conclusion, our study has uncovered the novel biophysical aspect of platelet biogenesis. The application of the new set of physical parameters in constructing large sized bioreactors shall facilitate the industrialization of platelet production. Disclosures Eto: Megakaryon Co. Ltd.: Research Funding.

Cell Cycle-Related Changes in Repopulating Capacity of Human Mobilized Peripheral Blood CD34+ Cells in Non-Obese Diabetic/Severe Combined Immune-Deficient Mice

Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2641-2649 ◽  
Author(s):  
André Gothot ◽  
Johannes C.M. van der Loo ◽  
D. Wade Clapp ◽  
Edward F. Srour
Keyword(s):  
Cell Cycle ◽  
Incubation Period ◽  
Peripheral Blood ◽  
Cell Cycle Progression ◽  
Ex Vivo ◽  
Scid Mice ◽  
Cd34 Cells ◽  
Mobilized Peripheral Blood

Abstract Most primitive hematopoietic progenitor cells reside in vivo within the G0/G1 phase of the cell cycle. By simultaneous DNA/RNA staining it is possible to distinguish G0 and G1 states and to isolate cells in defined phases of the cell cycle. We report here the use of cell cycle fractionation to separate human mobilized peripheral blood (MPB) CD34+ cells capable of repopulating the bone marrow (BM) of non-obese diabetic/severe combined immune-deficient (NOD/SCID) mice. In freshly isolated MPB, repopulating cells were predominant within the G0 phase, because transplantation of CD34+cells residing in G0 (G0CD34+) resulted on average in a 16.6- ± 3.2-fold higher BM chimerism than infusion of equal numbers of CD34+ cells isolated in G1. We then investigated the effect of ex vivo cell cycle progression, in the absence of cell division, on engraftment capacity. Freshly isolated G0CD34+ cells were activated by interleukin-3 (IL-3), stem cell factor (SCF), and flt3-ligand (FL) for a 36-hour incubation period during which a fraction of cells progressed from G0 into G1 but did not complete a cell cycle. The repopulating capacity of stimulated cells was markedly diminished compared with that of unmanipulated G0CD34+ cells. Cells that remained in G0 during the 36-hour incubation period and those that traversed into G1 were sorted and assayed separately in NOD/SCID recipients. The repopulating ability of cells remaining in G0 was insignificantly reduced compared with that of unstimulated G0CD34+ cells. On the contrary, CD34+ cells traversing from G0 into G1 were largely depleted of repopulating capacity. Similar results were obtained when G0CD34+ cells were activated by the combination of thrombopoietin-SCF-FL. These studies provide direct evidence of the quiescent nature of cells capable of repopulating the BM of NOD/SCID mice. Furthermore, these data also demonstrate that G0-G1 progression in vitro is associated with a decrease in engraftment capacity. © 1998 by The American Society of Hematology.

Cell Cycle-Related Changes in Repopulating Capacity of Human Mobilized Peripheral Blood CD34+ Cells in Non-Obese Diabetic/Severe Combined Immune-Deficient Mice

Blood ◽  
1998 ◽  
Vol 92 (8) ◽  
pp. 2641-2649 ◽  
Author(s):  
André Gothot ◽  
Johannes C.M. van der Loo ◽  
D. Wade Clapp ◽  
Edward F. Srour
Keyword(s):  
Cell Cycle ◽  
Incubation Period ◽  
Peripheral Blood ◽  
Cell Cycle Progression ◽  
Ex Vivo ◽  
Scid Mice ◽  
Cd34 Cells ◽  
Mobilized Peripheral Blood

Most primitive hematopoietic progenitor cells reside in vivo within the G0/G1 phase of the cell cycle. By simultaneous DNA/RNA staining it is possible to distinguish G0 and G1 states and to isolate cells in defined phases of the cell cycle. We report here the use of cell cycle fractionation to separate human mobilized peripheral blood (MPB) CD34+ cells capable of repopulating the bone marrow (BM) of non-obese diabetic/severe combined immune-deficient (NOD/SCID) mice. In freshly isolated MPB, repopulating cells were predominant within the G0 phase, because transplantation of CD34+cells residing in G0 (G0CD34+) resulted on average in a 16.6- ± 3.2-fold higher BM chimerism than infusion of equal numbers of CD34+ cells isolated in G1. We then investigated the effect of ex vivo cell cycle progression, in the absence of cell division, on engraftment capacity. Freshly isolated G0CD34+ cells were activated by interleukin-3 (IL-3), stem cell factor (SCF), and flt3-ligand (FL) for a 36-hour incubation period during which a fraction of cells progressed from G0 into G1 but did not complete a cell cycle. The repopulating capacity of stimulated cells was markedly diminished compared with that of unmanipulated G0CD34+ cells. Cells that remained in G0 during the 36-hour incubation period and those that traversed into G1 were sorted and assayed separately in NOD/SCID recipients. The repopulating ability of cells remaining in G0 was insignificantly reduced compared with that of unstimulated G0CD34+ cells. On the contrary, CD34+ cells traversing from G0 into G1 were largely depleted of repopulating capacity. Similar results were obtained when G0CD34+ cells were activated by the combination of thrombopoietin-SCF-FL. These studies provide direct evidence of the quiescent nature of cells capable of repopulating the BM of NOD/SCID mice. Furthermore, these data also demonstrate that G0-G1 progression in vitro is associated with a decrease in engraftment capacity. © 1998 by The American Society of Hematology.

scholarly journals A Novel DNA Methyltransferase Inhibitor Is Effective in an In Vivo Model of Myelodysplastic Syndrome

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 1804-1804
Author(s):  
Ghanwa Khawaja ◽  
Yang Jo Chung ◽  
Eunsil Park ◽  
Micheal Difilippantonio ◽  
James H. Doroshow ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Peripheral Blood ◽  
Dna Methyltransferase ◽  
Hematopoietic Cells ◽  
Survival Advantage ◽  
In Vivo Model ◽  
Cell Surface Antigens ◽  
Hematopoietic Stem

Abstract The myelodysplastic syndromes (MDS) are a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, peripheral blood cytopenias, dysplasia and a propensity for transformation to acute myeloid leukemia (AML). MDS is frequently associated with epigenetic gene silencing via methylation of cytosine residues in gene regulatory regions, and DNA methyl-transferase 1 (DNMT1) inhibitors, such as 5'azacytidine and 5-aza-2'-deoxycytidine (decitabine, DAC), are two of the three agents that are FDA approved for treatment of MDS. Although these drugs are not curative, they induce hematological improvement or improved survival in a significant fraction of MDS patients. Two novel, thiol-substituted 2'-deoxycytidine (dCyd) analogs designated T-dCyd (4'-thio-2'-deoxycytidine) and Aza-T-dCyd (5-aza-4'-thio-2'-deoxycytidine) were synthesized and shown to be potent DNMT1 inhibitors in vitro. We evaluated these drugs in vivo using the NUP98-HOXD13 (NHD13) mouse model for MDS. To mimic human MDS hematopoiesis, in which a portion of the hematopoietic output is provided by the MDS clone, and a portion provided by normal, non-MDS cells, we transplanted wild-type (WT) mice with a mixture of WT murine hematopoietic cells and NHD13 (MDS) hematopoietic cells. This bone marrow transplant (BMT) produces chimaeric recipients with bone marrow comprised of hematopoietic cells derived from both the MDS clone as well as normal hematopoietic precursors. WT and MDS cells in the mice can be distinguished by differential CD45 alleles (CD45.1 and CD45.2, respectively), which enables analysis and purification of the MDS and WT cells; this feat is not easily achieved with human MDS patient samples, which lack cell surface antigens specific for the MDS clone. At 8 weeks post-transplant; engraftment of MDS cells was documented by the presence of CD45.2+ cells in the peripheral blood, and the starting CBCs showed signs consistent with MDS including peripheral blood cytopenia and macrocytosis. Mice were randomly assigned to one of the three groups. 1) PBS, 2) T-dCyd, 3) Aza-T-dCyd. T-Cyd was dosed at 4 mg/kg/d intraperitoneally (IP) on weekdays for 2 weeks (10 doses), followed by three weeks rest; this constituted one cycle of therapy. Aza-T-dCyd was administered on the same schedule at 4 mg/kg/d IP. Flow cytometry and CBC were assessed on day 21 of each cycle, and treatment continued for up to one year, or until mice were humanely euthanized due to tachypnea, lethargy, or other signs of AML. Between four and six mice were treated per group, and the entire experiment was repeated three times and results pooled for T-dCyd, once for Aza-T-dCyd. The T-dCyd treated chimaeric mice showed significantly enhanced overall survival associated with hematological improvement including hemoglobin concentration, platelet and absolute neutrophil count compared to PBS treated mice (median survival 45.4 vs 28 weeks, p=0.0187). In addition to a survival advantage, AML onset was significantly delayed in the T-dCyd treated mice (median time to AML transformation 35 weeks for PBS vs unreached for T-dCyd, p=0.0111), although there was no significant change in MDS (CD45.2) engraftment between the T-dCyd and PBS treated mice. For Aza-T-dCyd group, we did not detect a survival benefit nor hematologic improvement, although we suspect this may have been secondary to unexpected toxicity at the selected dose. In sum, these results demonstrate the utility of chimaeric WT/MDS mice as a pre-clinical model for human MDS, and show that treatment with T-dCyd, a new DNMT1 inhibitor, leads to a survival advantage, hematologic improvement, and delayed transformation to AML. Disclosures Aplan: NIH Office of Technolgy Transfer: Employment, Patents & Royalties: NUP98-HOXD13 mice.

CD123 (IL-3 Receptor α Chain) Neutralization by a Monoclonal Antibody Selectively Eliminates Human Acute Myeloid Leukemic Stem Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 161-161 ◽  
Author(s):  
Richard B. Lock ◽  
Liqing Jin ◽  
Erwin M. Lee ◽  
Hayley S. Ramshaw ◽  
Sam Busfield ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Ex Vivo ◽  
Treated Group ◽  
Scid Mice ◽  
High Expression ◽  
Post Inoculation ◽  
Α Chain ◽  
Acute Myeloid

Abstract Development of effective therapies against acute myeloid leukemia (AML) will likely require elimination of the leukemic stem cell (LSC), which maintains the AML hierarchy. Based on high expression of the IL-3 receptor α chain (CD123) on AML-LSC, we tested a neutralizing antibody against CD123 (7G3) for its in vitro and in vivo effects on AML cells. By flow cytometric analysis, high expression of CD123 on CD34+/38− AML-LSC was confirmed. In vitro, 7G3 inhibited IL-3-induced proliferation in 31/34 primary AML specimens tested. Moreover, exposure of primary AML cells to 7G3 in vitro caused inhibition of IL-3-induced tyrosine phosphorylation and downstream signaling of the IL-3 receptor βc chain in a concentration-dependent fashion. Ex vivo treatment of primary AML cells with 7G3 (10 μg/ml, 2 h) profoundly reduced leukemic engraftment of human CD45+ (huCD45+) cells in non-obese diabetic/severe-combined immunodeficient (NOD/SCID) mice in 9/10 evaluable samples (mean ± SEM, 89.7 ±1.9% inhibition relative to IgG2a control, P=0.013), establishing that the AML-LSC was targeted. The overall survival of engrafted mice was significantly improved (median survival of control IgG2a-treated group 11.5 weeks versus 24 weeks for the 7G3-treated group, n = 10 per group, P=0.019). Moreover, ex vivo 7G3 treatment reduced the short-term homing efficiency of AML cells to the bone marrow by 65% compared with IgG2a control-treated cells, measured at 24 h post inoculation. In contrast, ex vivo exposure to 7G3 had minor, if any, effects on the engraftment of normal bone marrow cells (23.5 ±8.9% inhibition relative to IgG2a control, n=5). Direct delivery of 7G3-treated AML cells into the bone marrow by intra-femoral injection did not completely restore engraftment, suggesting a specific biological role of 7G3 in inhibiting homing, lodgement and proliferation of AML-LSC. Despite some sample to sample heterogeneity, thrice-weekly administration of 7G3 to NOD/SCID mice with pre-established AML consistently reduced AML dissemination to peripheral blood, spleen and liver, and reduced infiltration of a single AML sample in the bone marrow. 7G3 treatment was also associated with down-regulation of CD123 expression on AML cells in vivo. AML cells harvested from 7G3-treated mice were unable to repopulate secondary recipient mice, with engraftment reduced to 5.7 ±4.1% (n=7) huCD45+ cells in the femoral bone marrow compared with 26.8 ±6.6% in IgG2a-treated controls (n=9, P=0.024), indicating that CD123 neutralization targeted AML-LSC self-renewal ability, specifically reducing the proportion of AML-LSC. These results suggest that blocking CD123 inhibits homing, lodgement and proliferation of AML-LSC in the bone marrow microenvironment and prevents subsequent organ infiltration, and support additional investigations into 7G3 and its potential as a novel therapy for AML.

scholarly journals A clinically relevant SCID-hu in vivo model of human multiple myeloma

Blood ◽  
2005 ◽  
Vol 106 (2) ◽  
pp. 713-716 ◽  
Author(s):  
Pierfrancesco Tassone ◽  
Paola Neri ◽  
Daniel R. Carrasco ◽  
Renate Burger ◽  
Victor S. Goldmacher ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Fluorescent Protein ◽  
Severe Combined Immunodeficiency ◽  
Scid Mice ◽  
In Vivo Model ◽  
Fetal Bone ◽  
Experimental Drugs

Abstract We developed a novel in vivo multiple myeloma (MM) model by engrafting the interleukin 6 (IL-6)-dependent human MM cell line INA-6 into severe combined immunodeficiency (SCID) mice previously given implants of a human fetal bone chip (SCID-hu mice). INA-6 cells require either exogenous human IL-6 (huIL-6) or bone marrow stromal cells (BMSCs) to proliferate in vitro. In this model, we monitored the in vivo growth of INA-6 cells stably transduced with a green fluorescent protein (GFP) gene (INA-6GFP+ cells). INA-6 MM cells engrafted in SCID-hu mice but not in SCID mice that had not been given implants of human fetal bone. The level of soluble human IL-6 receptor (shuIL-6R) in murine serum and fluorescence imaging of host animals were sensitive indicators of tumor growth. Dexamethasone as well as experimental drugs, such as Atiprimod and B-B4-DM1, were used to confirm the utility of the model for evaluation of anti-MM agents. We report that this model is highly reproducible and allows for evaluation of investigational drugs targeting IL-6-dependent MM cells in the human bone marrow (huBM) milieu. (Blood. 2005;106:713-716)

scholarly journals Primitive Human Hematopoietic Cells Are Enriched in Cord Blood Compared With Adult Bone Marrow or Mobilized Peripheral Blood as Measured by the Quantitative In Vivo SCID-Repopulating Cell Assay

Blood ◽  
1997 ◽  
Vol 89 (11) ◽  
pp. 3919-3924 ◽  
Author(s):  
Jean C.Y. Wang ◽  
Monica Doedens ◽  
John E. Dick
Keyword(s):  
Bone Marrow ◽  
Cord Blood ◽  
Peripheral Blood ◽  
Hematopoietic Cells ◽  
Allogeneic Transplantation ◽  
Functional Assay ◽  
Hematopoietic Stem ◽  
Mobilized Peripheral Blood

Abstract We have previously reported the development of in vivo functional assays for primitive human hematopoietic cells based on their ability to repopulate the bone marrow (BM) of severe combined immunodeficient (SCID) and nonobese diabetic/SCID (NOD/SCID) mice following intravenous transplantation. Accumulated data from gene marking and cell purification experiments indicate that the engrafting cells (defined as SCID-repopulating cells or SRC) are biologically distinct from and more primitive than most cells that can be assayed in vitro. Here we demonstrate through limiting dilution analysis that the NOD/SCID xenotransplant model provides a quantitative assay for SRC. Using this assay, the frequency of SRC in cord blood (CB) was found to be 1 in 9.3 × 105 cells. This was significantly higher than the frequency of 1 SRC in 3.0 × 106 adult BM cells or 1 in 6.0 × 106 mobilized peripheral blood (PB) cells from normal donors. Mice transplanted with limiting numbers of SRC were engrafted with both lymphoid and multilineage myeloid human cells. This functional assay is currently the only available method for quantitative analysis of human hematopoietic cells with repopulating capacity. Both CB and mobilized PB are increasingly being used as alternative sources of hematopoietic stem cells in allogeneic transplantation. Thus, the findings reported here will have important clinical as well as biologic implications.

scholarly journals Novel Caprine Adeno-Associated Virus (AAV) Capsid (AAV-Go.1) Is Closely Related to the Primate AAV-5 and Has Unique Tropism and Neutralization Properties

2005 ◽  
Vol 79 (24) ◽  
pp. 15238-15245 ◽  
Author(s):  
Alejandra E. Arbetman ◽  
Michael Lochrie ◽  
Shangzhen Zhou ◽  
Jennifer Wellman ◽  
Ciaran Scallan ◽  
...  
Keyword(s):  
Protein Expression ◽  
Neutralization Assay ◽  
Biological Properties ◽  
Scid Mice ◽  
Factor Ix ◽  
In Vivo Model ◽  
Adeno Associated Virus ◽  
Human Factor Ix

ABSTRACT Preexisting humoral immunity to adeno-associated virus (AAV) vectors may limit their clinical utility in gene delivery. We describe a novel caprine AAV (AAV-Go.1) capsid with unique biological properties. AAV-Go.1 capsid was cloned from goat-derived adenovirus preparations. Surprisingly, AAV-Go.1 capsid was 94% identical to the human AAV-5, with differences predicted to be largely on the surface and on or under the spike-like protrusions. In an in vitro neutralization assay using human immunoglobulin G (IgG) (intravenous immune globulin [IVIG]), AAV-Go.1 had higher resistance than AAV-5 (100-fold) and resistance similar to that of AAV-4 or AAV-8. In an in vivo model, SCID mice were pretreated with IVIG to generate normal human IgG plasma levels prior to the administration of AAV human factor IX vectors. Protein expression after intramuscular administration of AAV-Go.1 was unaffected in IVIG-pretreated mice, while it was reduced 5- and 10-fold after administration of AAV-1 and AAV-8, respectively. In contrast, protein expression after intravenous administration of AAV-Go.1 was reduced 7.1-fold, similar to the 3.8-fold reduction observed after AAV-8administration in IVIG-pretreated mice, and protein expression was essentially extinguished after AAV-2 administration in mice pretreated with much less IVIG (15-fold). AAV-Go.1 vectors also demonstrated a marked tropism for lung when administered intravenously in SCID mice. The pulmonary tropism and high neutralization resistance to human preexisting antibodies suggest novel therapeutic uses for AAV-Go.1 vectors, including targeting diseases such as cystic fibrosis. Nonprimate sources of AAVs may be useful to identify additional capsids with distinct tropisms and high resistance to neutralization by human preexisting antibodies.

scholarly journals Transcription factor Gfi-1 induced by G-CSF is a negative regulator of CXCR4 in myeloid cells

Blood ◽  
2007 ◽  
Vol 110 (7) ◽  
pp. 2276-2285 ◽  
Author(s):  
Maria De La Luz Sierra ◽  
Paola Gasperini ◽  
Peter J. McCormick ◽  
Jinfang Zhu ◽  
Giovanna Tosato
Keyword(s):  
Bone Marrow ◽  
Dna Sequences ◽  
Peripheral Blood ◽  
Cell Function ◽  
Myeloid Cell ◽  
Cxcr4 Expression ◽  
Negative Regulator ◽  
Hematopoietic Stem

The mechanisms underlying granulocyte-colony stimulating factor (G-CSF)–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood remain elusive. We provide evidence that the transcriptional repressor growth factor independence-1 (Gfi-1) is involved in G-CSF–induced mobilization of granulocytic lineage cells from the bone marrow to the peripheral blood. We show that in vitro and in vivo G-CSF promotes expression of Gfi-1 and down-regulates expression of CXCR4, a chemokine receptor essential for the retention of hematopoietic stem cells and granulocytic cells in the bone marrow. Gfi-1 binds to DNA sequences upstream of the CXCR4 gene and represses CXCR4 expression in myeloid lineage cells. As a consequence, myeloid cell responses to the CXCR4 unique ligand SDF-1 are reduced. Thus, Gfi-1 not only regulates hematopoietic stem cell function and myeloid cell development but also probably promotes the release of granulocytic lineage cells from the bone marrow to the peripheral blood by reducing CXCR4 expression and function.

scholarly journals A novel BCMA/CD3 bispecific T-cell engager for the treatment of multiple myeloma induces selective lysis in vitro and in vivo

Leukemia ◽  
2016 ◽  
Vol 31 (8) ◽  
pp. 1743-1751 ◽  
Author(s):  
S Hipp ◽  
Y-T Tai ◽  
D Blanset ◽  
P Deegen ◽  
J Wahl ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
T Cell ◽  
Plasma Cells ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Selective Lysis ◽  
Bispecific T Cell Engager

Abstract B-cell maturation antigen (BCMA) is a highly plasma cell-selective protein that is expressed on malignant plasma cells of multiple myeloma (MM) patients and therefore is an ideal target for T-cell redirecting therapies. We developed a bispecific T-cell engager (BiTE) targeting BCMA and CD3ɛ (BI 836909) and studied its therapeutic impacts on MM. BI 836909 induced selective lysis of BCMA-positive MM cells, activation of T cells, release of cytokines and T-cell proliferation; whereas BCMA-negative cells were not affected. Activity of BI 836909 was not influenced by the presence of bone marrow stromal cells, soluble BCMA or a proliferation-inducing ligand (APRIL). In ex vivo assays, BI 836909 induced potent autologous MM cell lysis in both, newly diagnosed and relapsed/refractory patient samples. In mouse xenograft studies, BI 836909 induced tumor cell depletion in a subcutaneous NCI-H929 xenograft model and prolonged survival in an orthotopic L-363 xenograft model. In a cynomolgus monkey study, administration of BI 836909 led to depletion of BCMA-positive plasma cells in the bone marrow. Taken together, these results show that BI 836909 is a highly potent and efficacious approach to selectively deplete BCMA-positive MM cells and represents a novel immunotherapeutic for the treatment of MM.

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