scholarly journals Seven Cases of JAK2 Mutation Negative Chronic Polycythemia Patients with Elevated IGF-1R

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 5389-5389
Author(s):  
Guanfang Shi ◽  
Rewais Morcus ◽  
Maksim Liaukovich ◽  
Ching Wong ◽  
Vladimir Gotlieb ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Flow Cytometry ◽  
Polycythemia Vera ◽  
Mononuclear Cells ◽  
Jak2 V617f ◽  
Driver Mutations ◽  
Erythroid Progenitors ◽  
Jak2 Mutation ◽  
Minor Criteria

We previously reported that assaying blood MNC (Mononuclear cells) IGF-1 levels by Flow cytometry, will be helpful in differentiating Polycythemia vera (PV) from secondarypolycythemia (1). Patients with chronic polycythemia who are negative for JAK2 V617F or exon 12 mutation and who lack the typical bone marrow findings of polycythemia vera will remain a diagnostic enigma. We collected 7 cases of patients who had persistent chronic erythrocytosis ranging from 1-15 years with negative driver mutations, lacking the typical PV bone marrow findings and absence of secondary causes such as smoking or malignancies. Blood mononuclear cells (MNC ) were collected as well as blood DNA extracted for 237 genes including EPO-R, PHD2, VHL or HIF-1-alpha (Familial erythrocytosis genes)with Next generation sequence, performed by Genoptyx lab (Carisbad, CA) and assayed for IGF-1R by flow cytometry as described previously (1). The results are shown in Table 1. Conclusion. All these 7 patients with elevated IGF-1R who had no evidence of familial erythrocytosis gene mutation nor had any secondary cause for erythrocytosis, likely carried the diagnosis of PV. It was shown that EEC formation in PV is due to IGF-1 hypersensitivity (2), andsecondary polycythemia do not show significantly elevated IGF -1R (1). Hence the elevated IGF-1R in these 7 patients strongly suggests the diagnosis of PV, re-affirming our proposal that simple procedures to assay blood MNC cells for IGF-1R by flow cytometry will be helpful in the diagnosis of PV and to be added as one of the minor criteria in the diagnosis of PV. References 1. Wang JC, et al . Quantification of IGF-1 Receptor May Be Useful in Diagnosing Polycythemia Vera-Suggestion to Be Added to Be One of the Minor Criterion.PLoS One. 2016 Nov 3;11(11):e0165299. doi: 10.1371/journal.pone.0165299. 2. Correa PN, Eskinazi, D and Axelrad AA .Circulating Erythroid Progenitors in Polycythemia Vera Are Hypersensitive to Insulin-like Growth Factor-l In Vitro: Studies in an Improved Serum-Free Medium Blood, Vol83, No 1 (January l), 1994: pp 99-1 Disclosures Wang: Incyt: Research Funding.

Pure Heterozygous and Mixed JAK2 V617F Genotypes Result in Distinct Mechanisms of Erythrocytosis in Polycythemia Vera.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 662-662
Author(s):  
Sabrina Dupont ◽  
Aline Masse ◽  
Chloe James ◽  
Nicole Casadevall ◽  
William Vainchenker ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Progenitor Cells ◽  
Mononuclear Cells ◽  
Fold Increase ◽  
Jak2 V617f ◽  
Molecular Event ◽  
Erythroid Progenitors ◽  
Low Frequencies

Abstract The JAK2 V617F mutation is present in most patients with polycythemia vera (PV) and half with essential thrombocythemia (ET). Using real-time quantitative PCR, we analyzed the levels of JAK2 V617F in granulocytes and/or bone marrow mononuclear cells from 159 PV and 149 ET patients. High JAK2 V617F levels were correlated with higher leukocyte, granulocyte, hemoglobin values and higher endogenous erythroid colony formation. Thus, the phenotype of PV and ET may be closely linked to the JAK2 V617F level, which may reflect the clonal genotypic pattern of hematopoietic progenitor cells. It is thought that the occurrence of the mitotic recombination, which generates homozygous JAK2 V671F clones, is a key molecular event for the onset of PV. In this work, we aimed to study the consequences of the clonal JAK2 V617F genotype on the amplification properties and erythropoietin (EPO) hypersensitivity of PV (n=14) and ET (n=6) progenitors. Analysis of clonal genotypic patterns shows that ET patients harbor a mix of heterozygous and normal progenitors. Interestingly, we distinguish pure heterozygous PV profiles (3/14 patients) with no homozygous progenitors from homozygous PV profiles (11/14 patients) with normal, heterozygous and homozygous progenitors. Similar low frequencies of mutated immature progenitors, comprising long-term culture-initiating cells and lympho-myeloid progenitors, are found in ET and PV. In contrast, PV patients with pure heterozygous PV profiles have striking higher proportions (>90%) of mutated committed progenitors than other PV and ET patients. This result suggests a selective amplification of heterozygous cells in the early phases of hematopoiesis. Furthermore, by using increasing concentrations of EPO, homozygous mutated erythroid progenitors are demonstrated to be more sensitive to EPO than heterozygous ones, a majority of the former (69,5%) being EPO independent. Moreover, we demonstrate a two to three fold increase in in vitro amplification of ET and PV progenitor cells when compared to normal ones in serum free liquid culture containing IL3, Stem Cell Factor, Dexamethasone and 1 IU/mL EPO. In addition, the quantification of the mutated allele in immature CD34+CD38- cells, in CD34+CD38+ committed progenitor cells, in mature erythroblasts (GPA+) and in granulocytes shows a marked in vivo selective advantage of mutated cells in late stages of hematopoiesis. These results suggest that in PV, erythrocytosis results from two distinct mechanisms: a terminal erythroid amplification advantage triggered by homozygosity or a two-step process including the upstream amplification of heterozygous cells that may involve additional molecular event(s).

Will Imitanib Be Useful for Patients with Polycythemia Vera?.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2601-2601 ◽  
Author(s):  
Amos S. Gaikwad ◽  
Srdan Verstovsek ◽  
Ko-Tung Chang ◽  
Donghoon Yoon ◽  
William Vainchenker ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Glucose Uptake ◽  
Polycythemia Vera ◽  
Tyrosine Kinases ◽  
Kinase Activity ◽  
Jak2 V617f ◽  
Erythroid Progenitors ◽  
Jak2 Mutation

Abstract Polycythemia vera (PV) is an acquired myeloproliferative, clonal stem cell disorder characterized by cytokine hypersensitivity. Several groups reported a clonal mutation in the pseudo kinase domain of the Janus kinase 2 (Jak2) protein, substituting phenylalanine at position 617 with valine (V617F) that causes constitutive activation of the JAK/STAT pathway in PV patients. Chronic myelogenous leukemia is another myeloproliferative disorder associated with aberrant tyrosine kinase (bcr-abl) that arises from t(9:22) translocation. Constitutive bcr-abl tyrosine kinase activity suppresses apoptosis leading to survival and proliferation of cells at low cytokine concentrations. Imitanib has been developed to inhibit the bcr-abl kinase activity and has had impressive therapeutic efficacy. However, imitanib also inhibits other tyrosine kinases. Clinical benefits of imitanib in PV have been reported. Mouse FDCP cells over-expressing either the wild-type Jak2 (JAK/W) or two cell lines with the V617F mutation (V617F), one with cytokine hypersensitivity and the other cytokine independent, were created. We examined the effect of imitanib by MTT proliferation assay and propidium iodide staining analysis. No appreciable changes in the proliferation and DNA content were observed in all three cell-lines after imitanib treatment at ~1μM (the concentration effective for the bcr-abl expressing cells and achievable in vivo in imitanib treated patients). However, after 72h of exposure, the cells expressing JAK2 V617F mutant showed 50% inhibition of growth at ~6μM imitanib with no significant effect on the growth of cells expressing JAK/W. To further understand the mechanism of growth inhibition of V617F cells by imitanib, we examined the metabolism of these cells since the constitutively active tyrosine kinases has been demonstrated to change the glucose metabolism. Imitanib treatment (5μM) for 72h caused about 30% decrease in the glucose uptake in V617F cells with only a marginal (~5%) decrease in glucose uptake was observed in the JAK/W cells. We then examined the effect of imitanib on in vitro expanded native human erythroid progenitors (CD71 and CD235a positive cells) from three normal and four PV individuals who expressed variable proportion of mutant JAK2 V617F alleles. In this small study, between 18–30% decrease in the proliferation of the cells from PV patients was seen with 1–2μM of imitanib compared to 8% seen with normal erythroid progenitors; however, the in vitro expansion was accompanied by a decrease of proportion of cells with JAK2 mutation (see abstract Prchal et. Al. at this meeting). Further, in ongoing clinical studies, one of 5 tested PV patients who showed an excellent clinical response to imitanib therapy had decrease of V617F mutation from 58 to 19% in circulating granulocytes. We conclude that high concentration of imitanib is required to achieve the cytotoxic effects in reporter cells transfected with JAK2 mutation that are not readily achievable in vivo; however, lower doses (but still significantly higher than those needed for bcr-abl expressing cells) are effective in native PV progenitors. These data do not exclude possible useful therapeutic effect of imitanib in PV either alone or in combination with other drugs. Amos Gaikwad, Ph.D. and Srdan Verstovsek, M.D. contributed equally to this study.

In Vitro Expansion of Polycythemia Vera Progenitors Favors Expansion of Erythroid Precursors without JAK2 V617F Mutation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3506-3506 ◽  
Author(s):  
Josef T. Prchal ◽  
Ko-Tung Chang ◽  
Jaroslav Jelinek ◽  
Yongli Guan ◽  
Amos Gaikwad ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Polycythemia Vera ◽  
Peripheral Blood ◽  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Erythroid Progenitors ◽  
Erythroid Precursors ◽  
In Vitro Expansion ◽  
V617f Mutation

Abstract A single acquired point mutation of JAK2 1849G>T (V617F), a tyrosine kinase with a key role in signal transduction from growth factor receptors, is found in 70%–97% of patients with polycythemia vera (PV). In the studies of tyrosine kinase inhibitors on JAK2 1849G>T (see Gaikwad et all abstract at this meeting) we decided to study the possible therapeutic effect of these agents using native in vitro expanded cells from peripheral blood. To our surprise, the in vitro expansion of PV progenitors preferentially augmented cells without JAK2 1849G>T mutation. We used a 3 step procedure to amplify erythroid precursors in different stages of differentiation from the peripheral blood of 5 PV patients previously found to be homozygous or heterozygous for the JAK2 1849G>T mutation. In the first step (days 1–7), 106/ml MNCs were cultured in the presence of Flt-3 (50 ng/ml), Tpo (100 ng/ml), and SCF (100 ng/ml). In the second step (days 8–14), the cells obtained on day 7 were re-suspended at 106/ml in the same medium with SCF (50 ng/ml), IGF-1 (50 ng/ml), and 3 units/ml Epo. In the third step, the cells collected on day 14 were re-suspended at 106/ml and cultured for two more days in the presence of the same cytokine mixture as in the step 2 but without SCF. The cultures were incubated at 37oC in 5% CO2/95% air atmosphere and the medium renewed every three days to ensure good cell proliferation. The expanded cells were stained with phycoerythrin-conjugated anti-CD235A (glycophorin) and fluorescein isothiocyanate-conjugated anti-human-CD71 (transferrin receptor) monoclonal antibodies and analyzed by flow cytometry. The cells were divided by their differential expression of these antigens into 5 subgroups ranging from primitive erythroid progenitors (BFU-Es and CFU-Es) to polychromatophilic and orthochromatophilic erythroblasts; over 70% of harvested cells were early and late basophilic erythroblasts. The proportion of JAK2 1849G>T mutation in clonal PV granulocytes (GNC) before in vitro expansion and in expanded erythroid precursors was quantitated by pyrosequencing (Jelinek, Blood in press) and is depicted in the Table. These data indicate that in vitro expansion of PV progenitors favors expansion of erythroid precursors without JAK2 V617F mutation. Since three PV samples were from females with clonal granulocytes, erythrocytes, and platelets, experiments were underway to determine if the in vitro expanded erythroid cells were clonal PV cells without JAK2 V617F mutation, or derived from polyclonal rare circulating normal hematopoietic progenitors. The Proportion of JAK2 T Allele Patients GNC T Allele (%) Expanded Cells T Allele (%) PV1 (Female) 81 10 PV2 (Male) 77 28 PV3 (Male) 44 42 PV4 (Female) 78 19 PV5 (Female) 78 28

Dysregulated Expression of miRNAs in Polycythemia Vera Erythroid Progenitors.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3613-3613
Author(s):  
Hana Bruchova ◽  
Amos S. Gaikwad ◽  
Joshua Mendell ◽  
Josef T. Prchal
Keyword(s):  
Gene Expression ◽  
Polycythemia Vera ◽  
Jak2 V617f ◽  
Prediction Algorithm ◽  
Erythroid Cell ◽  
Molecular Defect ◽  
Erythroid Progenitors ◽  
Hematopoietic Stem ◽  
Homogeneous Population

Abstract Polycythemia vera (PV), the most common myeloproliferative disorder, arises due to somatic mutation(s) of a single hematopoietic stem cell leading to clonal hematopoiesis. A somatic JAK2 V617F point mutation is found in over 80% of PV patients; however, it is not clear if the JAK2 V617F is the disease initiating mutation, sincethere are PV JAK2 V617F negative patients who have monoclonal hematopoiesis and erythropoietin independent erythropoiesis;in individual PV families, there are PV subjects with and without the JAK2 V617F mutation; andanalysis of clonal PV populations reveals the presence of <50 and >50% mutated JAK2 cells (Nussenzweig’ abstract this mtg), suggesting a mixed population of cells with regard to JAK2 status.In order to search for possible PV contributing molecular defect(s), we studied microRNAs (miRNAs) in a homogeneous population of in vitro expanded erythroid progenitors. MiRNAs are non-coding, small RNAs that regulate gene expression at the posttranscriptional level by direct mRNA cleavage, by translational repression, or by mRNA decay mediated by deadenylation. MiRNAs play an important regulatory role in various biological processes including human hematopoiesis. In vitro expanded erythroid progenitors were obtained from peripheral blood mononuclear cells of 5 PV patients (JAK2 V617F heterozygotes) and from 2 healthy donor controls. The cells were cultured in an erythroid-expansion medium for 21 days resulting in 70–80% homogenous erythroid cell population of identical differentiation stage. Gene expression profiling of miRNAs (Thomson, Nature Methods, 1:1, 2004) was performed using a custom microarray (Combimatrix) with 326 miRNA probes. Data were normalized by the global median method. The miRNAs with expression ratios greater than 1.5 or less than 0.5 were considered to be abnormal. Comparative analyses of controls versus PV samples revealed up-regulated expression of miR-let7c/f, miR-16, miR-451, miR-21, miR-27a, miR-26b and miR-320 and down-regulation of miR-150, miR-339 and miR-346 in PV. In addition, miR-27a, miR-26b and miR-320 were expressed only in PV. The putative targets of these miRNAs were predicted by TargetScan prediction algorithm. Up-regulated miR-let-7, miR-16 and miR-26b may modulate cyclin D2, which has an important role in G1/S transition and can be a target in the JAK2/STAT5 pathway (Walz, JBC, 281:18177, 2006). One of the putative targets of up-regulated miR-27a is EDRF1 (erythroid terminal differentiation related factor1), a positive regulator of erythroid differentiation. The BCL-6 gene is predicted to be the target of miR-339 and miR-346, and its activation blocks cellular differentiation. MiR-16 is known to be down-regulated in CLL, where it targets anti-apoptotic BCL-2; in contrast, we show that miR-16 is up-regulated in PV erythroid cells. We identified differentially expressed miRNAs in PV which target genes involved in the JAK/STAT pathway or genes that are modulated by JAK2 downstream molecules. This study indicates that miRNA dysregulation may play an important role in erythropoietic differentiation and proliferation in PV. Expression analyses of these miRNAs in a larger set of PV samples, using quantitative Real-Time-PCR, are in progress. Further, earlier erythroid and pluripotent hematopoietic progenitors are also being analyzed.

Erythropoiesis in Polycythemia Vera Is Hyper-Proliferative and Has Accelerated Differentiation during In Vitro Erythroid Expansion and Is Associated with Higher Expressions of cMYB and EPOR at Early Erythroid Progenitors

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1549-1549
Author(s):  
Hana Bruchova ◽  
Donghoon Yoon ◽  
Archana Agarwal ◽  
Eva Otahalova ◽  
Hyojin Kim ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Mononuclear Cells ◽  
Early Stage ◽  
Severe Disease ◽  
Erythroid Differentiation ◽  
Erythroid Progenitors ◽  
Peripheral Blood Mononuclear ◽  
Healthy Donors ◽  
Differentiation Stage

Abstract Erythroid differentiation is a dynamic process leading to the production of mature red blood cells. Even small variations in this process may result in severe disease phenotype. To study this process, we used a three-phase erythroid expansion system to expand homogeneous erythroid progenitors (EPs) from peripheral blood mononuclear cells (PB-MNCs) (Bruchova H. et al, 2007, Exp. Hematology, in press). We then characterized the expanded EPs from polycythemia vera (PV) patients and healthy donors at various points of maturation comparing cell proliferation and differentiation stage. EPs from PV patients outgrew controls up to day 14 (∼12 fold for PV and ∼4 fold for control compared to day 1). Differentiation was analyzed using both FACS analysis (with CD71/CD235a staining) and morphological evaluation (Wright-Giemsa staining), and demonstrated a more rapid differentiation of PV EPs when compared to controls up to day 14. We then evaluated apoptosis/cell cycle analysis by propidium iodide staining. Although PV EPs contained larger S phase population (45%) than controls (34%) at day 11, the apoptosis proportion of PV EPs was increased ∼2 fold to control from day 14. To understand the molecular mechanism of these differences between PV and controls, we analyzed the gene expression of several known regulators in erythropoiesis - BCL2, EPOR, cMYB, p27. Two transcripts (EPOR and cMYB) showed unique profiles on PV EPs. The EPOR transcript increased earlier in PV; i.e. from day 7 until day 21 and reached a plateau at day 11, compared to day 9 until day 19 and plateau at day 14 in controls. In addition, PV EPs contained higher levels of EPOR transcripts than control on most of timepoints. Interestingly, cMYB, which is known to augment early progenitor proliferation, was highly expressed from day 7 in PV, through day 11. Control EPs also expressed cMYB from day 9 through day 11; however, cMYB levels from any stages of control EPs were markedly lower than PV EPs at day 7. In this study, we demonstrate that PV erythropoiesis has unique features of hyperproliferation and an accelerated differentiation. These features are associated with earlier and higher expressions of cMYB and EPOR at the early stage of erythropoiesis.

LY2784544, a Novel JAK2 Inhibitor, Decreases In Vitro Growth of Hematopoietic Human Progenitors From JAK2 V617F Positive Polycythemia Vera Patients

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 5054-5054 ◽  
Author(s):  
Lourdes Florensa ◽  
Beatriz Bellosillo ◽  
Leonor Arenillas ◽  
Liandong Ma ◽  
Richard Walgren ◽  
...  
Keyword(s):  
Polycythemia Vera ◽  
Peripheral Blood ◽  
Mononuclear Cells ◽  
Jak2 V617f ◽  
Jak2 V617f Mutation ◽  
Dependent Manner ◽  
In Vitro Growth ◽  
Vitro Assay ◽  
V617f Mutation

Abstract Abstract 5054 Introduction: The discovery of JAK2 V617F mutation in patients with myeloproliferative disorders (MPD) has opened new perspectives for the development of targeted therapies. We have studied the efficacy of a novel molecule LY2784544 with JAK2 inhibitory activity in the in vitro growth of myeloid progenitors from JAK2 V617F-positive polycythemia vera (PV) patients. Objectives: To investigate the efficacy of LY2784544 in the inhibition of endogenous(e)BFU-E and CFU-GM growth in PV patients. Methods: In vitro cultures in semisolid media were performed from peripheral blood mononuclear cells (PBMC) of 6 PV patients who had never received cytoreductive treatment (4 patients with homozygous JAK2 V617F and 2 patients with heterozygous JAK2 V617F). PBMC were suspended in methylcellulose (Methocult. StemCell, Vancouver, Canada) without the addition of EPO and containing 0–30.0 μM LY2784544 drug. Concurrent plates containing EPO were plated as control cultures. The medium was distributed in multidishes and they were incubated at 37° with 5% CO2 and 95% humidity. Hemoglobinized colonies and granulomonocytic colonies were counted on day 14 by standard criteria (BFU-E defined by an aggregate of >50 hemoglobinized cells or three or more erythroid subcolonies and CFU-GM was defined by an aggregate of >50 cells). Each in vitro assay was performed in duplicate. DNA was obtained from peripheral blood granulocytes from each patient to quantify the JAK2 V617F allele burden at the time of culture assay. Results: LY2784544, at concentrations ranging from 0.03–30.0 μM, inhibited growth of unselected peripheral blood eBFU-E and CFU-GM from PV patients carrying the JAK2 V617F mutation in a dose-dependent manner, although without achieving complete inhibition of all colonies (fig.1). Conclusions: In vitro studies show that LY2784544 decreases the eBFU-E and CFU-GM growth in therapy-naive JAK2 V617F positive PV patients. Our data suggest that LY2784544 may be a candidate for the treatment of MPD carrying the JAK2 V617F mutation. Disclosures: Ma: Eli Lilly and Company: Employment. Walgren:Eli Lilly and Company: Employment.

Mutation Of The Divalent Metal Transporter (Dmt1) Gene Results In Inefficient Induction Of The Erythroid Transcriptional Program Due To Latter Onset Of GATA-1 and Epor Expression

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 2197-2197
Author(s):  
Nikola Curik ◽  
Pavel Burda ◽  
Tomas Zikmund ◽  
Filipp Savvulidi ◽  
Monika Horvathova ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bone Marrow ◽  
Flow Cytometry ◽  
Iron Uptake ◽  
Stage Iv ◽  
Erythroid Progenitors ◽  
Ineffective Erythropoiesis ◽  
Divalent Metal Transporter ◽  
Epor Expression

Abstract Introduction Divalent metal transporter 1 (DMT1; SLC11A2) encodes trans-membrane protein variants that execute either non-heme iron absorption through apical duodenal membrane of enterocytes or transferrin-bound iron uptake through endosomal membrane of erythroid (and other) cells. Since 2005 several DMT1 mutations affecting accurate protein folding and localization were identified in patients with defective iron uptake leading to microcytic anemia, abnormal growth of erythroid progenitors in vitro, and iron overload in the liver. We have previously demonstrated that defective growth of DMT-1-mutatnt BFU-Es in vitro and anemia associated with ineffective erythropoiesis in vivo can be improved with high-dose erythropoietin (EPO) supplementation (Horvathova et al., 2012). Data from Dmt1-mutant mk/mk mice (Gunshin et al., 2005) suggested that the anemic phenotype is a result of ineffective erythropoiesis within bone marrow and spleen. Hypothesis DMT1-mutant erythropoiesis inhibits EPO receptor (EPOR) signaling whose end-point target as well as upstream activator is the key transcription factor GATA-1. This results in defective erythroid development characterized by impaired survival capacity of erythroid progenitors, increased apoptosis of erythroblasts, and dysregulation of erythroid gene expression leading to ineffective erythropoiesis. Materials Bone marrow cells of murine mk/mk mice were sorted using flow cytometry to obtain differentiating erythroid fractions based on antigens Cd71 and Ter119 (Sokolovsky et al., 2001) which were then subjected to gene expression analysis. Results Firstly, four consecutive fractions (proerythroblasts and early basophilic erythroblasts - stage I, late basophilic erythroblasts – stage II, chromathophillic and orthochromathophillic erythroblasts – stage III, and late chromathophillic erythroblasts and reticulocytes – stage IV) were isolated from mk/mk mice and control littermates. Flow cytometry showed enrichment in stages I and II and depletion in stage IV in the mk/mk bone marrow when compared to wild type controls, consistent with our previous data. In the spleen the major cellular enrichment was seen in stage III accompanied by cell depletion in stage IV. Gene expression of GATA-1 was markedly decreased at the onset (in stages I and II) of erythropoiesis while it was increased in terminal stage IV. The expression pattern of the GATA-1 target gene Epor was similar to that of GATA-1 expression, while expression of b-maj globin was significantly reduced indicating developmental delay of the erythroid Dmt1-mutant compartment (compared to wild type). Whereas GATA-1 and Epor expression is low in early erythropoiesis, a compensatory increase in their expression at later stages is not capable to efficiently upregulate b-maj globin. These data together with flow cytometry analysis identify a developmental blockade of erythropoiesis between stages II(III) and IV. To better understand whether Dmt1 levels regulate GATA-1 and Epor expression we used murine erythroleukemia (MEL) cells containing conditional (estrogen-regulated) transgene encoding GATA-1 fused with estrogen receptor ligand-binding domain (GER). MEL cells are cytologically characterized as proerythroblasts and early basophilic erythroblasts, stage I. Firstly, we established that GATA-1 upregulates Epor expression and directly binds to the Epor gene using RT-PCR, Immunoblotting, and chromatin immunoprecipitation (ChIP) in activated GER cells. Using ChIP-sequencing analysis of GATA-1 (and a panel of histone modifications) the GATA-1 enrichment was clearly identified at three distinct Epor regions in murine erythroblasts and differentiating MEL cells. Next, we downregulated Dmt1 using siRNA and observed that GATA-1-mediated upregulation of Epor in activated GER cells became inhibited. In addition, the knockdown of Dmt1 also inhibited steady state levels of GATA-1 in MEL cells by 25%. Conclusions Ineffective erythropoiesis in Dmt1-mutant mice is blocked at stages II (III) and display deregulation of the Epor signaling cascade involving GATA-1 and its targets. Our data thus interconnect iron uptake and the Epor/GATA-1 pathways and suggest their roles during erythroid pathogenesis upon DMT1 mutations. Grants: P305/11/1745, P301/12/P380, P305/12/1033, UNCE 204021, PRVOUK-P24/LF1/3, SVV-2012-264507, GAUK 251135 82210 Disclosures: No relevant conflicts of interest to declare.

scholarly journals Effect of stem cell factor on in vitro erythropoiesis in patients with bone marrow failure syndromes

Blood ◽  
1992 ◽  
Vol 80 (12) ◽  
pp. 3000-3008
Author(s):  
BP Alter ◽  
ME Knobloch ◽  
L He ◽  
AP Gillio ◽  
RJ O'Reilly ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stem Cell Factor ◽  
Mononuclear Cells ◽  
Bone Marrow Failure ◽  
Dyskeratosis Congenita ◽  
Normal Numbers ◽  
Erythroid Progenitors ◽  
Bone Marrow Failure Syndromes

Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.

scholarly journals Effect of stem cell factor on in vitro erythropoiesis in patients with bone marrow failure syndromes

Blood ◽  
1992 ◽  
Vol 80 (12) ◽  
pp. 3000-3008 ◽  
Author(s):  
BP Alter ◽  
ME Knobloch ◽  
L He ◽  
AP Gillio ◽  
RJ O'Reilly ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Stem Cell ◽  
Stem Cell Factor ◽  
Mononuclear Cells ◽  
Bone Marrow Failure ◽  
Dyskeratosis Congenita ◽  
Normal Numbers ◽  
Erythroid Progenitors ◽  
Bone Marrow Failure Syndromes

Abstract Stem cell factor (SCF) enhances normal hematopoiesis. We examined its effect in vitro on bone marrow and blood progenitors from patients with inherited bone marrow failure syndromes, including 17 patients each with Diamond-Blackfan anemia (DBA) and Fanconi's anemia (FA), 3 with dyskeratosis congenita (DC), and 1 each with amegakaryocytic thrombocytopenia (amega) and transient erythroblastopenia of childhood (TEC). Mononuclear cells were cultured with erythropoietin (Ep) alone or combined with SCF or other factors. SCF increased the growth of erythroid progenitors in cultures from 50% of normal controls, 90% of DBA, 70% of FA, 30% of DC, and the amega and TEC patients; normal numbers were reached in 25% of DBA studies. Improved in vitro erythropoiesis with SCF in all types of inherited marrow failure syndromes does not suggest a common defect involving kit or SCF, but implies that SCF may be helpful in the treatment of hematopoietic defects of varied etiologies.

Isolation of Human Bone Marrow Mesenchymal Stem Cells by a Novel Monoclonal Antibody, ZUC3.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2562-2562
Author(s):  
Xiaoyu Lai ◽  
He Huang ◽  
Li Huang ◽  
Fenfang Zeng
Keyword(s):  
Stem Cells ◽  
Monoclonal Antibody ◽  
Bone Marrow ◽  
Flow Cytometry ◽  
Cell Sorting ◽  
Mononuclear Cells ◽  
Human Mscs ◽  
Bone Marrow Mononuclear Cells ◽  
Multiple Differentiation

Abstract Objective: Due to absence of a single definitive marker of mesenchymal stem cells (MSCs) and low incidence in human bone marrow, the primary culture of MSCs, conventionally isolated with its characteristic of adherent, were considered to be heterogeneous containing of several subpopulations, which had currently limited our understanding of their biology and therapeutic applications. In our previous study, a novel murine monoclonal antibody (McAb) ZUC3 was produced by hybridoma technology, which was specifically reactive with human MSCs, while showed negative cross-reactivity when screened against a variety of human tissues. Now, ZUC3 antigen positive MSCs population would be further identified by magnetic-activated cell sorting (MACS). Methods: Bone marrow were taken from the iliac crest of normal healthy adult volunteers, and mononuclear cells were separated by density gradient centrifugation, then separated into positively- and negatively-labelled fractions with McAb ZUC3 by immunomagnetic activated cell sorting. The purity of positive cells was analyzed by flow cytometry, then ZUC3 antigen positive and negative cells were plated respectively in human MSCs medium consisting of 10% FBS, LG-DMEM. Characteristics of ZUC3 antigen positive cells phenotype was analyzed by flow cytometry, and proliferation and multiple differentiation potential of the cells was observed in vitro. Results: Flow cytometric analysis showed that ZUC3 antigen expression by cultured MSCs and mononuclear cells derived from bone marrow were 91.31±2.92%, 0.96±0.28% respectively, and western blotting showed the molecular mass of antigen was about 33KD. The purity of the recovered fractions for ZUC3 by MACS was 76.82±6.32%. The positive cells have adhered to culture flask in vitro, and the quantity of adhered cells that had fibroblast-like morphology increased and proliferated during primary expansion period, while the negative cells were observed as round shape cells without any proliferation. It was demonstrated that ZUC3 antigen positive cells continued growth with spindle-shape, extending beyond 30 population doublings in long-term culture. Analyzed by flow cytometry, the culture-expanded positive cells were uniformly positive for CD29, CD44, CD105, CD106, and lack typical hematopoietic antigens such as CD14, CD34, CD45, HLA-DR, which demonstrated that ZUC3 postive cells sorted from bone marrow mononuclear cells by McAb were MSCs. With proper medium, the ZUC3 antigen positive cells could be successfully induced to differentiate into adipocytes, osteoblasts, and neuro-like cells which were positive of neuron markers such as nestin, NSE and NF-M. Conclusion: ZUC3 McAb was a specific surface marker against human MSCs for cell sorting. The ZUC3 antigen positive cells separated from bone marrow mononuclear cells had potential capacity of high proliferation and multiple differentiation.

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